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Glutathione and immune function
Abstract
The immune system works best if the lymphoid cells have a delicately balanced intermediate level of glutathione. Even moderate changes in the intracellular glutathione level have profound effects on lymphocyte functions. Certain functions, such as the DNA synthetic response, are exquisitely sensitive to reactive oxygen intermediates and, therefore, are favoured by high levels of the antioxidant glutathione. Certain signal pathways, in contrast, are enhanced by oxidative conditions and favoured by low intracellular glutathione levels. The available evidence suggests that the lymphocytes from healthy human subjects have, on average, an optimal glutathione level. There is no indication that immunological functions such as resistance to infection or the response to vaccination may be enhanced in healthy human subjects by administration of glutathione or its precursor amino acid cysteine. However, immunological functions in diseases that are associated with a cysteine and glutathione deficiency may be significantly enhanced and potentially restored by cysteine supplementation. This factor has been studied most extensively in the case of human immunodeficiency virus (HIV)-infected patients who were found to experience, on average, a massive loss of S equivalent to a net loss of approximately 4 g cysteine/d. Two randomized placebo-controlled trials have shown that treatment of HIV-infected patients with N-acetyl-cysteine caused in both cases a significant increase in all immunological functions under test, including an almost complete restoration of natural killer cell activity. It remains to be tested whether cysteine supplementation may be useful also in other diseases and conditions that are associated with a low mean plasma cystine level and impaired immunological functions.
... Glutathione is fundamental to sustain an adequate function of the immune system, particularly affecting the lymphocyte activity since low GSH levels inhibit T-cell proliferation and immune response (Dröge and Breitkreutz, 2000;Ghezzi, 2011;Moro-García et al., 2018;Kelly and Pearce, 2020;Khanfar and Al Qaroot, 2020;Shyer et al., 2020). GSH depletion is strongly associated with impaired immune function and with disease development including viral diseases, cancer, cardiovascular diseases, arthritis and diabetes (Sinha et al., 2018;Sharifi-Rad et al., 2020;Silvagno et al., 2020;Fraternale et al., 2021;Matuz-Mares et al., 2021). ...
... GSH is essential for immunomodulation of both innate and adaptive immune system functions, including T-lymphocyte proliferation, polymorphonuclear neutrophil phagocytosis, and dendritic cell functions, and is also important for fine-tuning the innate immune response to infection and for the first step of adaptive immunity involving antigen-presenting cell (macrophages, dendritic cells)related antigen presentation (Morris et al., 2013;Diotallevi et al., 2017). GSH works to modulate the behavior of many immune cells, augmenting both, innate immunity (and trained innate immunity or innate immune memory; Netea et al., 2020;Chumakov et al., 2021;Ferreira et al., 2021;Gong et al., 2021;Brueggeman et al., 2022), severely affected by SARS-CoV-2 viral infection (Polonikov, 2020;Rodrigues et al., 2020;Forcados et al., 2021;Kozlov et al., 2021;Bellanti et al., 2022;Paludan and Mogensen, 2022), and adaptive immunity (Dröge et al., 1991;Dröge and Breitkreutz, 2000;Dröge, 2002c;Ghezzi, 2011;Morris et al., 2013;Fraternale et al., 2017), as well as conferring protection against oxidative stress caused by microbial, parasitic and viral infections such as SARS-CoV-2 that causes COVID-19 disease (Morris et al., 2013;Diotallevi et al., 2017;Derouiche, 2020;Polonikov, 2020;Silvagno et al., 2020;Suhail et al., 2020;Forcados et al., 2021;Pérez de la Lastra et al., 2021;Bellanti et al., 2022;Kumar P. et al., 2022). Persistent and uncontrolled oxidative stress and exacerbating NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome activation during severe COVID-19 disease (Lage et al., 2022), induce production of pro-inflammatory cytokines, such as IL-1β and IL-18, that can be explained because of sharply decreased macrophage GSH intracellular levels associated with increased GSH efflux (Zhang T. et al., 2021). ...
... GSH is capable of scavenging ROS through Nrf2-mediated heme oxygenase-1 induction and enhancing M1-like macrophage polarization regulation, showing that GSH may be a useful strategy to increase the human defense system (Mittal et al., 2014;Kwon et al., 2019;Funes et al., 2020). Strategies to enhance intracellular GSH levels such as supplementation of additional sources of cysteine (Deneke and Fanburg, 1989;Dröge et al., 1991;Lands et al., 1999;Dröge and Breitkreutz, 2000;Ghezzi et al., 2019;Gould and Pazdro, 2019;Minich and Brown, 2019;Castejon et al., 2021), oral and intravenous GSH (Cazzola et al., 2021), and sublingual and/or oral liposomal GSH administration (Schmitt et al., 2015;Campolo et al., 2017;Sinha et al., 2018;Guloyan et al., 2020; will also help to improve the immunological functions. The GSH and NAC digestive degradation occurring during oral treatments lead to consider GSH and NAC nebulization as a viable alternative to manage early stages of COVID-19 disease (Santos Duarte Lana et al., 2021). ...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 19 (COVID-19) has numerous risk factors leading to severe disease with high mortality rate. Oxidative stress with excessive production of reactive oxygen species (ROS) that lower glutathione (GSH) levels seems to be a common pathway associated with the high COVID-19 mortality. GSH is a unique small but powerful molecule paramount for life. It sustains adequate redox cell signaling since a physiologic level of oxidative stress is fundamental for controlling life processes via redox signaling, but excessive oxidation causes cell and tissue damage. The water-soluble GSH tripeptide (γ-L-glutamyl-L-cysteinyl-glycine) is present in the cytoplasm of all cells. GSH is at 1–10 mM concentrations in all mammalian tissues (highest concentration in liver) as the most abundant non-protein thiol that protects against excessive oxidative stress. Oxidative stress also activates the Kelch-like ECH-associated protein 1 (Keap1)-Nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) redox regulator pathway, releasing Nrf2 to regulate the expression of genes that control antioxidant, inflammatory and immune system responses, facilitating GSH activity. GSH exists in the thiol-reduced and disulfide-oxidized (GSSG) forms. Reduced GSH is the prevailing form accounting for >98% of total GSH. The concentrations of GSH and GSSG and their molar ratio are indicators of the functionality of the cell and its alteration is related to various human pathological processes including COVID-19. Oxidative stress plays a prominent role in SARS-CoV-2 infection following recognition of the viral S-protein by angiotensin converting enzyme-2 receptor and pattern recognition receptors like toll-like receptors 2 and 4, and activation of transcription factors like nuclear factor kappa B, that subsequently activate nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) expression succeeded by ROS production. GSH depletion may have a fundamental role in COVID-19 pathophysiology, host immune response and disease severity and mortality. Therapies enhancing GSH could become a cornerstone to reduce severity and fatal outcomes of COVID-19 disease and increasing GSH levels may prevent and subdue the disease. The life value of GSH makes for a paramount research field in biology and medicine and may be key against SARS-CoV-2 infection and COVID-19 disease.
... Evidencia en inmunización. La evidencia disponible sugiere que los linfocitos de sujetos humanos sanos mantienen, en promedio, una concentración óptima de glutatión y un balance estrecho de sus cantidades (29). Los cambios en el glutatión intracelular afectarían las funciones de los linfocitos. ...
... Los cambios en el glutatión intracelular afectarían las funciones de los linfocitos. Sin embargo, no hay hallazgos directos de que la respuesta de las células linfoides a la vacunación se potencie mediante la administración de glutatión o su precursor de cisteína en sujetos sanos (29). Las funciones inmunológicas en enfermedades que están asociadas con una deficiencia de cisteína y glutatión, en teoría, mejorarían y potencialmente se restaurarían mediante la suplementación con cisteína. ...
... Las funciones inmunológicas en enfermedades que están asociadas con una deficiencia de cisteína y glutatión, en teoría, mejorarían y potencialmente se restaurarían mediante la suplementación con cisteína. Esto se ha estudiado más extensamente en el caso de pacientes con VIH y pérdida masiva de cisteína (29,30). Dos ensayos aleatorizados controlados con placebo reportaron que el tratamiento con la NAC de pacientes con VIH se asoció con un aumento significativo de las funciones inmunológicas, incluida una restauración casi completa de la actividad de las células natural killer (NK). ...
Introducción: La N-acetilcisteína (NAC) es uno de los medicamentos que se ha propuesto en el manejo de pacientes con covid-19. Este fármaco cuenta con más de cincuenta años de uso en profilaxis y terapia de varias condiciones clínicas. Objetivo: Revisar la literatura que recoja la evidencia disponible sobre el uso de NAC como adyuvante en inmunización y tratamiento de covid-19, así como sobre su uso en infecciones causadas por otros virus ARN. Métodos: Se revisó Medline y la base de datos de estudios clínicos Clinical Tril con los términos clave n-acetyl cysteine, covid-19 y vaccination. Se examinaron las referencias de los artículos incluidos para obtener evidencia adicional relevante. Resultados: Se encontraron 151 referencias, de las cuales fueron incluidas 42. Estas incluyeron evidencia sobre los planteamientos teóricos, resultados de estudios clínicos y experimentación básica que describen la utilización de NAC en tratamiento, prevención de covid-19, así como sobre los mecanismos de acción, uso, eficacia y seguridad en esta y otras infecciones causadas por virus ARN. Conclusiones: La administración de NAC podría mejorar ciertos desenlaces clínicos en covid-19. Se requieren ensayos clínicos adicionales que investiguen su efectividad en pacientes con covid-19 o durante la vacunación.
... The glutathione cycle is one of the main intracellular mechanisms to preserve an adequate intracellular redox state [11,60]. In fact, GSH is the major antioxidant involving in cell-signaling regulation, whereas GSSG is highly toxic to cells [60]. ...
... The glutathione cycle is one of the main intracellular mechanisms to preserve an adequate intracellular redox state [11,60]. In fact, GSH is the major antioxidant involving in cell-signaling regulation, whereas GSSG is highly toxic to cells [60]. Therefore, an optimal GSSG/GSH balance is essential for the preservation of oxidative damage and the maintenance of immune functions [11,60]. ...
... In fact, GSH is the major antioxidant involving in cell-signaling regulation, whereas GSSG is highly toxic to cells [60]. Therefore, an optimal GSSG/GSH balance is essential for the preservation of oxidative damage and the maintenance of immune functions [11,60]. In our study, NDD-CKD patients showed in PMNs and MNs lower GSH content, together with higher GSSG and GSSG/GSH ratios, compared with controls. ...
Oxidative stress plays a key role in the pathophysiology of chronic kidney disease (CKD). Most studies have investigated peripheral redox state focus on plasma, but not in different immune cells. Our study analyzed several redox state markers in plasma and isolated peripheral polymorphonuclear (PMNs) and mononuclear (MNs) leukocytes from advanced-CKD patients, also evaluating differences of hemodialysis (HD) and peritoneal dialysis (PD) procedures. Antioxidant (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH)) and oxidant parameters (xanthine oxidase (XO), oxidized glutathione (GSSG), malondialdehyde (MDA)) were assessed in plasma, PMNs and MNs from non-dialysis-dependent-CKD (NDD-CKD), HD and PD patients and healthy controls. Increased oxidative stress and damage were observed in plasma, PMNs and MNs from NDD-CKD, HD and PD patients (increased XO, GSSG and MDA; decreased SOD, CAT, GPX and GSH; altered GSSG/GSH balance). Several oxidative alterations were more exacerbated in PMNs, whereas others were only observed in MNs. Dialysis procedures had a positive effect on preserving the GSSG/GSH balance in PMNs. Interestingly, PD patients showed greater oxidative stress than HD patients, especially in MNs. The assessment of redox state parameters in PMNs and MNs could have potential use as biomarkers of the CKD progression.
... Because certain activities, such as the DNA synthesis response, are extremely sensitive to reactive oxygen intermediates, high amounts of the antioxidant glutathione are beneficial. Conversely, oxidative circumstances and low intracellular glutathione levels encourage certain signal pathways [6]. In general glutathione has many functions [5,7]. ...
... Many human disorders have been linked to low glutathione levels, according to extensive study in numerous fields, such as emphysema, asthma, allergy disorders, medication toxicity, metabolic disorders, cancer, chemotherapy, and human immunodeficiency virus-acquired immune deficiency syndrome are only a few of the conditions and causes. [6,7] There is little research on the role of glutathione supplementation in these disorders, the majority of the research has focused on autism and cystic fibrosis. [9,10] The degree of inconstancy in a person's ability to provide glutathione, which is mostly owing to hereditary changeability in chemical components involved in its formation and recovery, is a factor influencing glutathione renown, glutathione stransferase and gamma-glutamyltransferase are two enzymes that convert glutathione to glutamate and have received a lot of attention in the logical writing and internal clinical medicinal drug, one of those catalysts requires complement cofactors [11]. ...
Abstract
Glutathione is a thiol-tripeptide with a low molecular weight that is important
for maintaining intracellular redox balance. Its antimelanogenic qualities have led to
its promotion as a skin-lightening agent, in addition to its exceptional antioxidant
properties. In some ethnic groups, it is commonly utilized for this purpose. There is,
however, a discrepancy between the evidence supporting its efficacy and safety. The
marketing gimmick surrounding its depigmenting properties could be a pharma�cosmeceutical company's marketing ploy. This article examines the different
characteristics of glutathione, including its metabolism, mechanism of action, and
scientific evidence to assess its usefulness as a systemic skin-lightening agent.
Glutathione, in its reduced form, is found within cells and plays a crucial part in a
variety of physiological functions. The direct and indirect suppression of the
tyrosinase enzyme, as well as the switch from eumelanin to phaeomelanin production,
are responsible for its skin-lightening effects. It can be taken orally, parent rally, or
topically. Although intravenous glutathione injections are widely used, there is little
proof that they are effective. Indeed, the Philippines' Food and Drug Administration
has issued a public warning denouncing intravenous glutathione's usage for off-label
applications such as skin whitening due to its negative consequences. There are now
three randomized controlled trials that support topical and oral glutathione's skin�lightening impact and good safety profile. However, important questions such as
treatment duration, skin-lightening impact lifetime, and maintenance regimens remain
unsolved. To establish the importance of this chemical in hyperpigmentation and skin
lightening diseases, more randomized, double-blind, placebo-controlled trials with
bigger sample sizes, long-term follow-up, and well-defined efficacy outcomes are
needed.
... As summarized in Table 1, decreased levels of antioxidants have been reported in both acute COVID-19 and ME/CFS. Foremost among these small molecules is glutathione, which helps modulate immune activation (76,77). Glutathione also enhances vitamin D metabolism (78) and vitamin D, in turn, reciprocally increases glutathione and decreases oxidative stress and levels of inflammatory cytokines and chemokines (79). ...
... Glutathione plays a particularly important role in enabling and modulating the immune response (76). It is vital for proliferation of T lymphocytes; T cell activation, in turn, generates glutathione, which counters ROS levels and mediates a metabolic shift toward aerobic glycolysis and glutaminolysis (113) Other connections between inflammation and redox imbalance exist as well. ...
Although most patients recover from acute COVID-19, some experience postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection (PASC). One subgroup of PASC is a syndrome called “long COVID-19,” reminiscent of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). ME/CFS is a debilitating condition, often triggered by viral and bacterial infections, leading to years-long debilitating symptoms including profound fatigue, postexertional malaise, unrefreshing sleep, cognitive deficits, and orthostatic intolerance. Some are skeptical that either ME/CFS or long COVID-19 involves underlying biological abnormalities. However, in this review, we summarize the evidence that people with acute COVID-19 and with ME/CFS have biological abnormalities including redox imbalance, systemic inflammation and neuroinflammation, an impaired ability to generate adenosine triphosphate, and a general hypometabolic state. These phenomena have not yet been well studied in people with long COVID-19, and each of them has been reported in other diseases as well, particularly neurological diseases. We also examine the bidirectional relationship between redox imbalance, inflammation, energy metabolic deficits, and a hypometabolic state. We speculate as to what may be causing these abnormalities. Thus, understanding the molecular underpinnings of both PASC and ME/CFS may lead to the development of novel therapeutics.
... It is crucial in enhancing the immunity via protecting immune cells through antioxidant mechanism and also it is essential for both innate and adaptive immunity. [87] According to Kuppner et al. [88] 2003, glutathione is important for T-lymphocytes proliferation, phagocytic activity of neutrophils in addition to the function of dendritic cell. Glutathione was used in trial for treating COVID-19 in USA. ...
Coronavirus is a family of RNA viruses that come from the genus beta coronavirus, this virus is distributed in many species like, birds, humans and other mammals. Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus. In most infected people with COVID-19 virus, the symptoms will appear as mild to moderate respiratory, symptoms and most of them can recover without needing specific treatment. On the other hand, older people and those with fundamental medical, problems such as, cardiovascular disease, diabetes, chronic respiratory disease and cancer are more likely to develop a serious illness and require special care and treatment.
... Glutathione depletion has been implicated in worsening the pathology of disease via mechanisms related to oxidative stress and inflammation [91,94]. Several risk factors for worsened COVID-19 illness are also positive risk factors for having lower endogenous glutathione concentrations, such as being a male (due to testosterone and estrogens effects on glutathione [95], 65 years of age or older, having a chronic disease, being a smoker, and having a diet low in fruits and vegetables [94,96]. Glutathione may also have anti-viral properties such as protecting host cells via its antioxidant capabilities, boosting immune cell function, and inhibiting viral replication [94]. ...
... For example, kynurenine, the metabolite of tryptophan metabolism involving IDO1, could mediate inflammatory responses, oxidative stress, and immune suppression in addition to causing endothelial dysfunction [61][62][63]. Similarly, glutathione, as an antioxidant and signaling molecule, could modulate natural killer (NK) cell and T cell responses [64][65][66][67][68][69][70]. Other metabolites upregulated in this group, such as glycerophosphate, glucose-6-phosphate, pyruvate, and malate, are involved in energy metabolism [71][72][73][74]. ...
Freund’s adjuvants have been used in vaccine and autoimmune settings, and their effects can be overlapping or unique to each. While both incomplete Freund’s adjuvants (IFA) and complete Freund’s adjuvants (CFA) influence antibody and T cell responses, the robust T helper 1 cytokines induced by the mycobacterial components make CFA the powerful immunostimulating adjuvant. In these studies, the adjuvant effects are investigated in a select population of cells, and the changes, if any, with the metabolic alterations in the systemic compartment are unclear. We investigated whether the effects of IFA and CFA can be influenced by the metabolic shifts in mice immunized with saline, IFA, or CFA using Mycobacterium tuberculosis var. bovis Bacillus Calmette–Guérin (BCG) as a positive control. After seven days of immunization, we analyzed the serum metabolite profiles using liquid chromatography coupled with high-resolution mass spectrometry and multivariate statistical analysis to identify metabolic features between the groups. The data revealed that, in the scores space, the CFA and BCG groups were more closely aligned compared to the saline group, while the IFA group displayed an intermediate profile. Furthermore, comparisons between the CFA and BCG groups showed more significant perturbations in lipid and amino acid metabolism, particularly involving glycerophospholipids, cysteine, and aromatic amino acids. In contrast, comparisons between the BCG and IFA groups indicated a more pronounced disruption in central energy metabolism pathways, such as the citric acid cycle and pyruvate metabolism. Together, the data suggest that the serum metabolite profiles in response to IFA and CFA might play a role in modulating the immune responses.
... Netgi nedideli viduląstelinio glutationo lygio pokyčiai turi poveikį limfocitų funkcijoms. Tam tikros funkcijos, pvz., DNR sintetinis atsakas, yra ypač jautrios reaktyviesiems deguonies tarpiniams produktams, todėl jas skatina didelis antioksidanto glutationo kiekis [11]. ...
Glutationas, dažnai vadinamas pagrindiniu natūraliu organizmo antioksidantu, padeda palaikyti ląstelių sveikatą ir kovoti su oksidaciniu stresu. Šis mažos molekulinės masės tripeptidas, sudarytas iš amino rūgščių – glutamato, cisteino ir glicino – labai svarbus detoksikacijos procesams, imuninės sistemos veiklai ir apsaugai nuo oksidacinės pažaidos. Atsižvelgiant į jo reikšmę, labai svarbu palaikyti pakankamą glutationo kiekį organime, siekiant užtikrinti bendrą sveikatą ir užkirsti kelią ligoms.
... The effective operation of our immune system depends on maintaining a finely tuned intermediate level of GSH within lymphoid cells. Even slight changes in intracellular GSH levels can adversely affect the functions of lymphocytes [52]. Cellular GSH depletion often results from the downregulation of expression or reduction of the specific activities of the first biosynthetic enzyme, glutamate-cysteine ligase [53]. ...
Durian (Durio zibethinus L.), a tropical fruit celebrated in Southeast Asia for its distinct flavor, is the focus of this comprehensive review. The fruit’s pulp is rich in high-value bioactive compounds, including gamma-glutamylcysteine, a precursor to the essential antioxidant glutathione. With durian cultivation gaining prominence in Southeast Asia due to its economic potential through cultivar enhancement, an in-depth examination of durian-related research becomes crucial. This review explores the health benefits of durian, analyzing the nutritional compositions and bioactive compounds present in the pulp, peel, and seed. It also underscores durian-based food products and the potential for valorizing durian waste. This review encapsulates the significant advancements made in omics-based research, aimed at deciphering the molecular complexities of durian fruit post-harvest ripening and the metabolic shifts impacting its sensory attributes. It is the first to summarize studies across genome, transcriptome, and metabolome levels. Future research should prioritize the development of molecular markers to accelerate the breeding of elite cultivars with preferred traits. It also proposes the exploration of durian waste valorization, including underexplored parts like flowers and leaves for their bioactive compounds, to promote a sustainable bioeconomy. Finally, it suggests the development of innovative durian products catering to the tastes of health-conscious consumers.
... Besides its involvement in the detoxification process, GSH also plays a vital role in lymphocyte function. Depleting GSH content was associated with impaired immune response and increased risk of malignancy [45] . ...
Exposure to arsenic from drinking water poses a significant threat to public health worldwide. Clerodendrum volubile and Vernonia amygdalina are potent natural sources of antioxidants to mitigate the toxic effect of arsenic. This study evaluated the effects of flavonoid fractions from C. volubile and V. amygdalina (FICV and FIVA) on the thiol cycling pathways and ion regulation of male albino rats exposed to sub-acute arsenic. Thirty male rats were randomly divided into six treatment groups. Control animals (distilled water), arsenic (40 ppm arsenic), arsenic + FICV (100 mg/ kg), arsenic + FIVA (100 mg/kg), arsenic + FICV and FIVA (50 mg/kg each) and arsenic + Vitamin C (100 mg/kg). The treatment commenced four weeks after exposure to arsenic in drinking water and continued for a further four weeks. The liver and kidneys of the rats were excised following an overnight fast. Arsenic had caused significant (p<0.05) reductions in the total protein levels and metallothionein levels, reduced glutathione levels in the liver and kidneys, and decreased glutathione-S-transferase enzymatic activity. Additionally, essential elements (magnesium, zinc, copper and calcium) were significantly reduced (p<0.05) in the arsenic-exposed rats. Study results showed that the reductions were reversed after treatment with FICV and FIVA. This study concludes that flavonoid fractions from C. volubile and V. amygdalina possess potent therapeutic actions against arsenic-induced oxidative stress and toxicity in male albino rats.
... Decreased level of GSH is linked somewhere with a depressed immune response [81,79] [90]. Nordberg et al. (1975) [91] reported the kidney also as a target organ for Generally, antioxidants reduce Cd absorption in the small intestine, and most of the ingested Cd is released along with fecal material resulting in a minimum reach of Cd to different tissues [92]. ...
Silver nanoprisms and their nanoconjugates can be used for different medical purposes
... Cysteine, a sulfur-containing amino acid, participates in the synthesis of glutathione within cells, thereby influencing the cellular redox state. Variations in cysteine supply can potentially impact the antioxidant capacity and immune activity of immune cells (Droge and Breitkreutz 2000). ...
Apart from cancer, metabolic reprogramming is also prevalent in other diseases, such as bacterial infections. Bacterial infections can affect a variety of cells, tissues, organs, and bodies, leading to a series of clinical diseases. Common Pathogenic bacteria include Helicobacter pylori, Salmonella enterica, Mycobacterium tuberculosis, Staphylococcus aureus, and so on. Amino acids are important and essential nutrients in bacterial physiology and support not only their proliferation but also their evasion of host immune defenses. Many pathogenic bacteria or opportunistic pathogens infect the host and lead to significant changes in metabolites, especially the proteinogenic amino acids, to inhibit the host’s immune mechanism to achieve its immune evasion and pathogenicity. Here, we review the regulation of host metabolism, while host cells are infected by some common pathogenic bacteria, and discuss how amino acids of metabolic reprogramming affect bacterial infections, revealing the potential adjunctive application of amino acids alongside antibiotics.
... It involves the invasion of the brain by circulating immune cells. Due to blood-brain barrier (BBB) failure and microglial activation, such immune cell infiltrations happen throughout the development of many diseases 14,15 . ...
Endotoxin Lipopolysaccharide (LPS) induces an innate immune response and activates sickness behavior. During neuroinflammation, the activated microglial cells change its morphology and release various chemicals that could be harmful such as nitric oxide (NO), reactive oxygen species (ROS) and enzymes for proteolysis. Through the buildup of free radicals and ROS, these neuroinflammations can also result in oxidative stress. This ROS reacts with cellular macromolecules, triggering a cascade that results in membrane porosity caused by membrane lipid peroxidation (LPO), which is measured by the quantity of malondialdehyde (MDA). On LPS challenge, the complex behaviour that decreased common activities and explorations, is noticed and with rising anxiety, cognitive impairment and decreased social activities. It also decreased closed arm time, although closed arm entries were higher which may be related to the increased locomotion. It raised open arm time and open arm entries, suggesting of reduced anxiety and also increased exploratory behaviour. AChE and nNOS were increased in the forebrain part. Reduction in brainstem and MDA activity decreased on both forebrain and brain stem. MDA in the liver increased by LPS challenge indicating upregulated hepatic tissue damage and oxidative stress. As a result of LPS-induced lipid peroxidation and oxidative stress, brain Glutathione (GSH), a substrate for cytosolic Glutathione peroxidase, increased in the forebrain and decreased in the brainstem. Decreased scavenging of ROS was indicated by the LPS-induced decrease in liver GSH levels.
... Glutathione possesses a wide range of effects on the immune system, either activating or suppressing the immune response to control inflammation. In particular, reduced glutathione is required for the control of innate and adaptive immunological processes such as T-lymphocyte proliferation, the phagocytic activity of polymorphonuclear neutrophils, and dendritic cell functions, as well as antigen presentation by antigen-presenting cells [80][81][82]. Changes in glutathione concentrations may be critical in many autoimmune disease disorders, in-cluding psoriasis [83]. In particular, glutathione may suppress the immune reaction in mice with allergic contact dermatitis [84], inhibit the production of inflammatory cytokines, and maintain the adequate production of interferon-gamma by dendritic cells [80]. ...
The aim of this pilot study was to investigate whether single nucleotide polymorphisms (SNP) in the gene encoding the catalytic subunit of glutamate cysteine ligase (GCLC) are associated with the risk and clinical features of psoriasis. A total of 944 unrelated individuals, including 474 patients with a diagnosis of psoriasis and 470 healthy controls, were recruited for the study. Six common SNPs in the GCLC gene were genotyped using the MassArray-4 system. Polymorphisms rs648595 (OR = 0.56, 95% CI 0.35–0.90; Pperm = 0.017) and rs2397147 (OR = 0.54, 95% CI 0.30–0.98; Pperm = 0.05) were associated with susceptibility to psoriasis in males. In the male group, diplotype rs2397147-C/C × rs17883901-G/G was associated with a decreased risk of psoriasis (FDR-adjusted p = 0.014), whereas diplotype rs6933870-G/G × rs17883901-G/G (FDR-adjusted p = 0.045) showed an association with an increased disease risk in females. The joint effects of SNPs with tobacco smoking (rs648595 and rs17883901) and alcohol abuse (rs648595 and rs542914) on psoriasis risk were observed (Pperm ≤ 0.05). We also found multiple sex-independent associations between GCLC gene polymorphisms and various clinical features such as earlier disease onset, the psoriatic triad, and specific localizations of skin lesions. The present study is the first to show that polymorphisms of the GCLC gene are significantly associated with the risk of psoriasis and related to its clinical features.
... Glutathione has been shown to have a wide range of effects on the immune system, either activating or suppressing the immune response to control inflammation. In particular, reduced glutathione is required for the control of innate and adaptive immunological processes such as T-lymphocyte proliferation, phagocytic activity of polymorphonuclear neutrophils, and dendritic cell functions, as well as antigen presentation by antigen-presenting cells [80,81,82]. Changes in glutathione concentrations may be critical in many autoimmune disease disorders, including psoriasis, that are commonly induced, detrimented, and perpetuated by inflammatory or immune responses mediated by ROS [83]. ...
The aim of this pilot study was to investigate whether single nucleotide polymorphisms (SNP) in the gene encoding the catalytic subunit of glutamate cysteine ligase (GCLC) are associated with the risk and clinical features of psoriasis. A total of 944 unrelated individuals, including 474 patients with a diagnosis of psoriasis and 470 healthy controls, were recruited for the study. Six common SNPs in the GCLC gene were genotyped using the MassArray-4 system. Polymorphisms rs648595 (OR=0.56 95%CI 0.35-0.90, Pperm=0.017) and rs2397147 (OR=0.54 95%CI 0.30-0.98, Pperm=0.05) were associated with susceptibility to psoriasis in males. In the male group, diplotype rs2397147-C/C×rs17883901-G/G was associated with decreased risk of psoriasis (FDR-adjusted P=0.014), whereas diplotype rs6933870-G/G×rs17883901-G/G (FDR-adjusted P=0.045) showed association with increased disease risk in females. Joint effects of SNPs with tobacco smoking (rs648595 and rs17883901) and alcohol abuse (rs648595 and rs542914) on the risk of psoriasis were observed (Pperm≤0.05). Furthermore, we found multiple sex-independent associations between GCLC gene polymorphisms and various clinical features such as earlier disease onset, the psoriatic triad, and specific localizations of skin lesions. The present study is the first to show that polymorphisms of the GCLC gene are significantly associated with the risk of psoriasis and related to its clinical features.
... In light of this mechanism, it is possible that some of the pathologies of viral infection may simply be "collateral damage" consequent to this primary goal of enhancing viral replication. Given their multiple roles in antioxidant defense, maintenance of redox homeostasis, and immune cell functioning [58][59][60][61], it is obvious that if these two essential biological reducing agents (TXNRD1 and GSH) are disrupted, the resulting increased oxidative stress and pro-inflammatory conditions, with pathological consequences, are to be expected. ...
Associations between dietary selenium status and the clinical outcome of many viral infections, including SARS-CoV-2, are well established. Multiple independent studies have documented a significant inverse correlation between selenium status and the incidence and mortality of COVID-19. At the molecular level, SARS-CoV-2 infection has been shown to decrease the expression of certain selenoproteins, both in vitro and in COVID-19 patients. Using computational methods, our group previously identified a set of six host proteins that contain potential SARS-CoV-2 main protease (Mpro) cleavage sites. Here we show experimentally that Mpro can cleave four of the six predicted target sites, including those from three selenoproteins: thioredoxin reductase 1 (TXNRD1), selenoprotein F, and selenoprotein P, as well as the rate-limiting enzyme in glutathione synthesis, glutamate-cysteine ligase catalytic subunit (GCLC). Cleavage was assessed by incubating recombinant SARS-CoV-2 Mpro with synthetic peptides spanning the proposed cleavage sites, and analyzing the products via UPLC-MS. Furthermore, upon incubation of a recombinant Sec498Ser mutant of the full TXNRD1 protein with SARS-CoV-2 Mpro, the predicted cleavage was observed, destroying the TXNRD1 C-terminal redox center. Mechanistically, proteolytic knockdown of both TXNRD1 and GCLC is consistent with a viral strategy to inhibit DNA synthesis, conserving the pool of ribonucleotides for increased virion production. Viral infectivity could also be enhanced by GCLC knockdown, given the ability of glutathione to disrupt the structure of the viral spike protein via disulfide bond reduction. These findings shed new light on the importance of dietary factors like selenium and glutathione in COVID-19 prevention and treatment.
... Reduced glutathione portrays a higher affinity for different NMs, and it further reduces available GSH. Decreased glutathione is linked with a lowered immune function [154,156]. Increased levels of GSH in the cadmium-exposed group (G2) might be linked with an elevated immune response. The alteration in the level of MTs referred to metals-induced toxicity in animal tissues. ...
Biomolecules-based surface modifications of nanomaterials may yield effective and biocompatible nanoconjugates. This study was designed to evaluate gold nanoconjugates (AuNCs) for their altered antioxidant potential. Gold nanoparticles (AuNPs) and their conjugates gave SPR peaks in the ranges of 512–525 nm, with red or blueshift for different conjugates. Cys-AuNCs demonstrated enhanced (p < 0.05) and Gly-AuNCs (p > 0.05) displayed reduced DPPH activity. Gly-AuNCs and Tyr-AuNCs displayed enhanced ferric-reducing power and hydrogen peroxide scavenging activity, respectively. Cadmium-intoxicated mice were exposed to gold nanomaterials, and the level of various endogenous parameters, i.e., CAT, GST, SOD, GSH, and MTs, was evaluated. GSH and MTs in liver tissues of the cadmium-exposed group (G2) were elevated (p < 0.05), while other groups showed nonsignificance deviations than the control group. It is concluded that these nanoconjugates might provide effective nanomaterials for biomedical applications. However, more detailed studies for their safety profiling are needed before their practical applications.
... Moreover, it may be suggested that the natural antioxidants in CM play an important role in mitochondrial bioenergetics. The ability of CM to improve GSH production can also be traced to its high content of polyphenols which enhance the uptake of L-cysteine (the limiting substrate for GSH synthesis) (Dröge and Breitkreutz, 2000;Maher et al., 2008). ...
Context: Parkinson's disease (PD) is a multisystem neurodegenerative disorder associated with oxidative stress and disrupted mitochondrial function. It is characterized by motor and non-motor symptoms due to multi-factors. Coconut (Cocos nucifera) milk contains a complex mixture of highly nutritional constituents such as carbohydrates, vitamins, and minerals which have remarkable health benefits. Lauric acid (LA) which makes up 54.5% of the total nutrient composition of coconut milk (CM) possesses strong antioxidant properties. Objectives: This study evaluated the effect of CM on PD-associated motor and non-motor deficits in alpha-synuclein (α-syn) transgenic Drosophila melanogaster (D. melanogaster). Methods: W 1118 strain (control) and α-syn transgenic (PD strain) of D. melanogaster aged between 1 to 3 days were randomized into various groups. The control flies were fed on untreated diets, while the PD flies were orally exposed to varying concentrations (0, 5, 10, and 15% v/v) of the coconut milk diet for 14 days. Subsequently, longevity, behavioral, fecundity, and biochemical analyses were conducted across the groups. Results: The results showed that CM significantly increased longevity, climbing ability, egg count, and the rate of emergence (P< 0.05). In addition, MDA and NO levels as well as AChE activity were significantly decreased, while GSH levels alongside SOD and CAT activities were increased (P< 0.05) in the CM-treated PD flies in a concentration-dependent manner. Conclusions: CM ameliorated PD-associated deficits in D. melanogaster by prolonging lifespan, and improving locomotor function, fecundity, and redox status.
... En este sentido, son varios los reportes en la literatura que relacionan las alteraciones de la homeostasis del GSH con la aparición y progresión de estados inflamatorios y autoinmunes. (4,5) Revista Cubana de Hematología, Inmunología y Hemoterapia. 2022;38(2):e1602 4 Esta obra está bajo una licencia https://creativecom m ons.org/licenses/b y -nc/4.0/deed.es_E ...
Introducción:
Las alteraciones en el estado redox celular se han descrito como factores causales en diversas enfermedades. La depleción del glutatión reducido se ha asociado fundamentalmente a enfermedades neurodegenerativas, pulmonares, hepáticas, cardiovasculares e inmunológicas.
Objetivo:
Determinar las concentraciones de glutatión reducido y el estado redox celular en pacientes pediátricos con inmunodeficiencias.
Métodos:
Se estudiaron 21 pacientes con inmunodeficiencias procedentes de la consulta de Inmunogenética, en edades comprendidas entre 1 y 8 años, de ambos sexos, y 8 niños en el mismo rango de edad de los pacientes, como grupo control, con estudios de inmunidad humoral y celular normales. Los pacientes con diagnóstico de inmunodeficiencia se dividieron para su estudio en 2 grupos según el componente afectado de la respuesta inmune: humoral y celular. Fueron determinadas las concentraciones intraeritrocitarias de glutatión reducido y oxidado, mediante un método de HPLC-UV. Para evaluar el estado redox celular se calculó la relación entre las formas reducidas y oxidadas del glutatión (GSH/GSSG).
Resultados:
Las concentraciones de glutatión reducido y el estado redox celular se encontraron disminuidos en ambos grupos de pacientes en relación con los niños sin inmunodeficiencia (p=0,031 y p=0,03; respectivamente). El glutatión oxidado no mostró diferencias entre los grupos.
Conclusiones:
En los pacientes con inmunodeficiencia se evidenció la afectación del estado redox celular como consecuencia de la disminución del glutatión reducido. Este primer acercamiento ofreció las potencialidades del empleo de estos biomarcadores en la evaluación integral de pacientes con inmunodeficiencia.
... Glutathione level was increased using the other treatments, mainly when rats were fed turmeric supplement which gave the highest glutathione content in both the liver and kidneys. In addition, turmeric supplements had critical Immunological functions including prohibiting the disorders connected with the reduction of glutathione levels [50]. Despite feeding a meal containing cysteine and methionine supplements, either individually or in combination, as in groups (2, 3 and 4), the group fed a meal containing spirulina, which the protein may reach about 65 to 70% records higher glutathione. ...
Background: Oxidative stress occurs due to decreased glutathione inside the body. Some supplements may promote and stimulate glutathione production in the liver. This article aims to investigate the impact of different supplements on enhancing glutathione synthesis in rats’ livers. For this purpose 42 rats (male albino) were separated into 7 groups, each including 6 animals with average weights ranging between 150 and 160 g. Group 1 (control) and different groups consumed a basal diet for 8 weeks, whereas group 2 received 500 mg/kg bw of L-cysteine daily. Group 3 received 250 mg/kg bw of methionine, while group 4 got 250 mg/kg of L cysteine plus 125 mg/kg of methionine daily. Spirulina (20 mg/kg bw), turmeric (500 mg/kg bw), and dried garlic (500 mg/kg bw), respectively, were given to groups 5, 6, and 7. Results: Utilizing the various dietary supplements decreased levels of liver function enzymes, bilirubin, urea, creatinine, and malondialdehyde while enhancing levels antioxidant enzymes of liver, and increased glutathione of kidneys and liver. However, cysteine alone at 500 mg/kg bw decreased glutathione formation in the liver and kidneys. Compared to the amino acid supplements (group 2, 3, 4) used, spirulina, turmeric, and dried garlic had a significant impact on reducing liver function enzymes, bilirubin, uric acid, creatinine, urea, and malondialdehyde and increasing antioxidant enzymes, and glutathione while turmeric supplement showed the best influence. Using dietary supplements did not result in any pathological modifications in the liver tissues, but there were some unsatisfactory minor alterations. However, group 2 showed considerable pathological developments in the liver tissues. Conclusion: According to the findings, using the suggested dietary supplement except for cysteine alone can promote and encourage glutathione synthesis in different organs, especially the liver, hence alleviating the effects of oxidative stress associated with several illnesses.
... Glutathione is the most abundant non-protein thiol compound in all living organisms [1]. Because of its important physiological functions including its ability to act as an antioxidant, a detoxifier of xenobiotics, and an immune booster [2][3][4][5][6][7][8], glutathione has been widely used in the medical, food and cosmetic industries [9,10]. Therefore, the demand for glutathione has increased in recent years. ...
Background
Glutathione is a valuable tri-peptide that is industrially produced by fermentation using the yeast Saccharomyces cerevisiae , and is widely used in the pharmaceutical, food, and cosmetic industries. It has been reported that addition of l -serine ( l -Ser) is effective at increasing the intracellular glutathione content because l -Ser is the common precursor of l -cysteine ( l -Cys) and glycine (Gly) which are substrates for glutathione biosynthesis. Therefore, we tried to enhance the l -Ser biosynthetic pathway in S . cerevisiae for improved glutathione production.
Results
The volumetric glutathione production of recombinant strains individually overexpressing SER2 , SER1 , SER3 , and SER33 involved in l -Ser biosynthesis at 48 h cultivation was increased 1.3, 1.4, 1.9, and 1.9-fold, respectively, compared with that of the host GCI strain, which overexpresses genes involved in glutathione biosynthesis. We further examined simultaneous overexpression of SHM2 and/or CYS4 genes involved in Gly and l -Cys biosynthesis, respectively, using recombinant GCI strain overexpressing SER3 and SER33 as hosts. As a result, GCI overexpressing SER3 , SHM2 , and CYS4 showed the highest volumetric glutathione production (64.0 ± 4.9 mg/L) at 48 h cultivation, and this value is about 2.5-fold higher than that of the control strain.
Conclusions
This study first revealed that engineering of l -Ser and Gly biosynthetic pathway are useful strategies for fermentative glutathione production by S. cerevisiase .
... In healthy cells and tissue, more than 90% of the total glutathione pool is in the reduced form and less than 10% exists in the disulfide form [7]. A shift in the ratio of these two forms can be an indication of cellular oxidative stress, when glutathione changes from the reduced form (GSH) to the oxidized form (GSSG) [8]. Recently, many studies have shown that alteration in glutathione concentration in human fluids directly leads to several pathological diseases such as diabetes, Parkinson's disease, macular degeneration, HIV disease, and numerous types of cancers [9][10][11]. For these reasons, the use of sensitive detection methods for monitoring glutathione levels in physiological systems is highly demanded. ...
Oxidation of the reduced form of glutathione based on the 1:1 copper(Cu⁺²)-glutathione(GSH) complexes was found to occur at a decreased overpotential at a glassy carbon electrode modified with highly ordered mesoporous silica thin films (MSTFs) by means of the electrochemically assisted self-assembly (EASA) process. Adsorption of complexes can be performed on the electrode by taking advantage of the anionic nature of the silica walls of the MSTF which provide an excellent fixation site for accumulation of the Cu⁺²-GSH complex. The current response of voltammetric glutathione sensor is monitored at low oxidation potential of − 0.10 V versus standard mercury/mercurous sulfate reference electrode which makes the proposed sensor applicable to minimize interference from easily oxidizable species in the analysis of biological fluids. The proposed method represents a sensitive voltammetric sensor with a good linear detection range of 1.0–35.0 µM, which is in the range of GSH concentration in physiological fluids reported in literature with a suitable limit of detection of 0.08 µM. The proposed sensor offers several advantages such as being rapid and cost-effective, having good reproducibility, simple operation, and nontoxicity for glutathione detection.
... Glutathione also plays a critical role in immune system function and has been demonstrated to possess antioxidant and detoxifying activities by binding to drugs or toxins through sulfhydryl (Dröge and Breitkreutz 2000, Wu et al. 2004, Forman et al. 2009). Glutathionerelated indicators, such as glutathione-S-transferase and total glutathione, are considered as biomarkers correlated with critical insect physiological functions; furthermore, glutathione-related indicators reportedly participate in chlorantraniliprole resistance. ...
Parasitic Trichogramma chilonis Ishii, an egg parasitoid of Grapholita molesta, is a critical agent for biological control of insect pests in crop plants. However, the efficiency of T. chilonis is influenced by its resistance to the common pesticide chlorantraniliprole. To elucidate the chlorantraniliprole detoxification mechanism, differentially expressed genes (DEGs) related to chlorantraniliprole resistance were studied at different developmental stages of the wasp. Individuals of T. chilonis were grouped and treated with chlorantraniliprole at different developmental stages. Untreated wasps were used as controls. Transcriptomic analysis identified the DEGs associated with chlorantraniliprole resistance and detoxification in T. chilonis. A total of 1,483 DEGs were associated with chlorantraniliprole resistance at all developmental stages. DEGs that correlated with chlorantraniliprole sensitivity of T. chilonis at different developmental stages were distinct and had various functions. The newly identified DEGs are involved in cytochrome P450- and glutathione metabolism-related pathways, which were predicted to contribute to chlorantraniliprole detoxification. Chlorantraniliprole detoxification by T. chilonis was associated with cytochrome P450- and glutathione-related pathways. Our findings may be useful for balancing chemical and biological control practices aimed to optimize agricultural production.
... Glutathione (GSH), is the most potent antioxidant or detoxifier in cells, is responsible for maintaining redox status, as well as many cellular processes, including gene expression, DNA and protein synthesis, cell proliferation and apoptosis, and immune response [39,40]. RNAseq of bone marrow neutrophils revealed an increase in expression of enzymes involved in glutathione metabolism/synthesis in neutrophils treated with C42B CM, compared to LNCaP media (Fig. 3E). ...
Bone metastatic prostate cancer (BM-PCa) remains one of the most difficult cancers to treat due to the complex interactions of cancer and stromal cells. We previously showed that bone marrow neutrophils elicit an anti-tumor immune response against BM-PCa. Further, we demonstrated that BM-PCa induces neutrophil oxidative burst, which has previously been identified to promote primary tumor growth of other cancers, and a goal of this study was to define the importance of neutrophil oxidative burst in BM-PCa. To do this, we first examined the impact of depletion of reactive oxygen species (ROS), via systemic deletion of the main source of ROS in phagocytes, NADPH oxidase (Nox)2, which we found to suppress prostate tumor growth in bone. Further, using pharmacologic ROS inhibitors and Nox2-null neutrophils, we found that ROS depletion specifically suppresses growth of androgen-insensitive prostate cancer cells. Upon closer examination using bulk RNA sequencing analysis, we identified that metastatic prostate cancer induces neutrophil transcriptomic changes that activates pathways associated with response to oxidative stress. In tandem, prostate cancer cells resist neutrophil anti-tumor response via extracellular (i.e., regulation of neutrophils) and intracellular alterations of glutathione synthesis, the most potent cellular antioxidant. These findings demonstrate that BM-PCa thrive under oxidative stress conditions and such that regulation of ROS and glutathione programming could be leveraged for targeting of BM-PCa progression.
... By enhancing all lines of host defense that include soluble and cellular components of innate immunity, cellular components of both innate and adaptive immunity and soluble and cellular components of the adaptive immune system will certainly help humans defeat this pandemic killer (2). Considering the impact that cytokine storm and oxidative stress have during SARS-CoV-2 infection toward development of a severe disease, the concomitant administration of both nuclear factor erythroid 2 p45-related factor 2 (Nrf2) activators such as sulforaphane and glutathione (GSH) synthesis precursors such as N-acetyl cysteine, cysteine, and cystine can increase (a) nuclear Nrf2 translocation and antioxidant response element transcription and (b) synthesis of GSH, the most powerful antioxidant of the body, respectively (11)(12)(13), facilitating prevention against oxidative stress, inflammation, and cell and tissue damage in SARS-CoV-2 infection and COVID-19 disease. Replenishing the nutritional status of the host by (a) increasing vital amino acids such as cysteine and/or (b) providing GSH itself, through liposomal administration (14) to enhance GSH levels, and (c) supplementing selenium to improve selenium deficiency and facilitate selenoprotein (GSH peroxidases, thioredoxin reductases) expression (15) can inhibit oxidative stress, modulating inflammation and endothelial dysfunction. ...
... It is a ubiquitous molecule and provides defence against free radicals, hydroperoxides and other harmful oxidants. However, its production declines with age, and is often given orally or administered intravenously [24][25][26] , which causes its increased plasma concentration. Our studies show that incubation of α2M with GSH (20-100 µM) results in loss of functional status of this antiproteinase. ...
Background: Glutathione (GSH) is a principle thiol-containing tripeptide (cysteine, glutamic acid and glycine) antioxidant against free radicals and other harmful oxidants in cellular defence. The alpha-2-macroglobulin (α2M) is large tetrameric zinc-binding glycoprotein which inhibits proteinases regardless of their specificity and catalytic mechanism.
Materials and Methods: The interaction of GSH was analyzed with α2M including the structural and functional alterations in α2M using various biochemical and biophysical methods. UV-visible and fluorescence spectroscopy were used to study the binding of α2M with GSH and Fourier transform infrared (FT-IR) spectroscopy was explored to study the structural change induced in α2M.
Results: The results suggest that exposure of α2M to GSH decreases the antiproteolytic potential as suggested by the amidase assay. The UV-spectroscopic study showed the formation of α2M-GSH complex and fluorescence analysis showed significant quenching in fluorescence intensity of α2M suggesting GSH binding and structural alteration in the protein. FT-IR spectroscopy was explored to study the structural change induced in α2M which suggest that the secondary structure of α2M changes upon complex formation.
Conclusion: Our studies show that interaction of α2M with photoilluminated GSH results in functional and conformational changes of the protein.
Keywords: glutathione, GSH, alpha-2-macroglobulin, photo-illumination, ITC, FTIR
... Glutathione, a crucial antioxidant, is well known to modulate the behavior of many cells including the cells of the immune system, augmenting the innate and the adaptive immunity as well as conferring protection against microbial, viral and parasitic infections [42,43]. Interaction between GSH metabolism and several diseases were also well described [44]. ...
... Role of GSH Reference Enhancement of immune system function Protects against inflammatory pathologies Impaired immunological function caused by cysteine and glutathione deficiency is restored when supplemented with cysteine [7,8] Prevention of oxidative cell damage Serves as an antioxidant [9,10] Prostaglandin synthesis Inhibits prostaglandin synthesis at elevated levels [11] Transport of metals across membranes ...
Glutathione is a remarkably functional molecule with diverse features, which include being an antioxidant, a regulator of DNA synthesis and repair, a protector of thiol groups in proteins, a stabilizer of cell membranes, and a detoxifier of xenobiotics. Glutathione exists in two states—oxidized and reduced. Under normal physiological conditions of cellular homeostasis, glutathione remains primarily in its reduced form. However, many metabolic pathways involve oxidization of glutathione, resulting in an imbalance in cellular homeostasis. Impairment of glutathione function in the brain is linked to loss of neurons during the aging process or as the result of neurological diseases such as Huntington’s disease, Parkinson’s disease, stroke, and Alzheimer’s disease. The exact mechanisms through which glutathione regulates brain metabolism are not well understood. In this review, we will highlight the common signaling cascades that regulate glutathione in neurons and glia, its functions as a neuronal regulator in homeostasis and metabolism, and finally a mechanistic recapitulation of glutathione signaling. Together, these will put glutathione’s role in normal aging and neurological disorders development into perspective.
... Glutathione is considered as an important antioxidant in the immune system for two causes; first, it protects the immune cells of the host through its antioxidant mechanism against different types of reactive oxygen species as in Table 1 [20] , second, it provides the best working of immune system cells like lymphocytes and other cells. [21] It is considered as an essential factor for the proliferation of T-cell, neutrophil phagocytic activity, and dendritic cell function. [22] So, the decreasing of glutathione levels is associated with an increased susceptibility to infection and disease such as G6DP, [23] cystic fibrosis, [24] and influenza infection. ...
The immune system is a complicated system; it is consisted from network of specialized organs, tissues, cells, proteins, and chemicals which it has
the function to protect the host from various types of pathogens such as bacteria, virus, fungi, and parasite in addition to cancer cells. Antioxidants
are defined as agents that can prevent the damage that is caused by free radicals through scavenging of them. They decrease the damage by
neutralizing to the free radicals before they attack any of the cells and can prevent lipids, enzymes, proteins, carbohydrates, and DNA damage.
... Glutathione is considered as an important antioxidant in the immune system for two causes; first, it protects the immune cells of the host through its antioxidant mechanism against different types of reactive oxygen species as in Table 1 [20] , second, it provides the best working of immune system cells like lymphocytes and other cells. [21] It is considered as an essential factor for the proliferation of T-cell, neutrophil phagocytic activity, and dendritic cell function. [22] So, the decreasing of glutathione levels is associated with an increased susceptibility to infection and disease such as G6DP, [23] cystic fibrosis, [24] and influenza infection. ...
The immune system is a complicated system; it is consisted from network of specialized organs, tissues, cells, proteins, and chemicals which it has
the function to protect the host from various types of pathogens such as bacteria, virus, fungi, and parasite in addition to cancer cells. Antioxidants
are defined as agents that can prevent the damage that is caused by free radicals through scavenging of them. They decrease the damage by
neutralizing to the free radicals before they attack any of the cells and can prevent lipids, enzymes, proteins, carbohydrates, and DNA damage
... GSH is a reduced form of GST and has a greater affinity for AgNPs which also causes the deficiency of available GSH. A decrease in glutathione is associated with a decreased level of immune function [62,63]. An increase in GSH level for the cadmium group (G2) might be due to an increase in the immune response. ...
Recent data suggest that there is a continuous need to develop safer and less toxic nanomaterials (NMs). For this, the surface chemistry of commonly used NMs may be modified using several biomolecules/conjugates. The current study has been designed to develop silver nanoconjugates (AgNCs) capped with different amino acids. Characterization of the same was performed using different techniques. During in vitro analysis, l-tyrosine and l-cystine capped AgNCs exhibited antioxidant activity, while l-glycine capped AgNCs showed prooxidant activity. l-cystine and l-tyrosine capped AgNCs also demonstrated good in vivo results. The level of catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), and metallothioneins (MTs) in different organs was evaluated. It is assumed that newly developed nanoconjugates can be utilized as nano-tools for different applications. However, more detailed studies with resolution techniques for safety, the risk associated, and their accuracy are needed for the utilization of these nanoconjugates for specific biomedical uses.Graphical abstract
... The products of amino acid metabolism were the substrates of the citrate cycle, which may also be one of the reasons to accelerate the citrate cycle in the rumen epithelia. Glutathione metabolism plays a key role in the pathogenesis of many diseases, and is related to oxidative stress (Droge and Breitkreutz, 2000;Liang et al., 2019). Thus, appropriate regulation of glutathione metabolism is necessary for host health (Wu et al., 2004). ...
The present study aimed to comparatively characterize the ruminal epithelial protein expression profiles in lambs fed ewe milk or milk plus starter diet using proteome analysis. twenty new-born lambs were randomly divided into a group receiving ewe milk (M, n = 10) and a group receiving milk plus starter diet (M + S, n = 10). From 10-d-old, M group lambs remained with the ewe and suckled ewe milk without receiving the starter diet. The lambs in the M + S group were separated from the ewe and received starter feed. All lambs were slaughtered at 56-d-old. Eight rumen epithelia samples (4 per group) were collected to characterize their protein expression profiles using proteomic technology. Proteome analysis showed that 31 upregulated proteins and 40 downregulated proteins were identified in the rumen epithelium of lambs in response to starter diet supplementation. The results showed that starter feeding regulates a variety of biological processes in the epithelium, especially blood vessel development and extracellular matrix protein expression. Meanwhile, the expression of proteins associated with synthesis and degradation of ketone bodies, butanoate metabolism, and citrate cycle signaling transduction pathway were upregulated in the group with starter diet supplementation, including 3-hydroxy-3-methylglutaryl coenzyme A synthase (HMGCS2, fold change [FC] = 1.93), 3-hydroxybutyrate dehydrogenase 1 (BDH1, FC = 1.91), and isocitrate dehydrogenase 1 (IDH1, FC = 8.12). The metabolic processes associated with ammonia detoxification and antioxidant stress were also affected by starter diet supplementation, with proteins, microsomal glutathione S-transferase 3 (MGST3, FC = 2.37) and IDH1, linked to the biosynthesis of glutamate and glutathione metabolism pathway being upregulated in the group with starter diet supplementation. In addition, starter feeding decreased the expression of Ras-related protein rap-1A (RAP1A, FC = 0.48) enriched in Rap1 signaling pathway, Ras signaling pathway, cyclic adenosine monophosphate (cAMP) signaling pathway, and mitogen-activated protein kinase (MAPK) signaling pathway. In summary, starter feed supplementation changed the expression of proteins related to energy production, ammonia detoxification, antioxidant stress, and signaling pathways related to proliferation and apoptosis, which facilitates the rumen epithelia development in lambs. The results provide new insights into the molecular adaptation of rumen epithelia in response to starter diet supplementation at the protein level in lambs.
... Human plasma or serum contains nearly 250 lM of Cys [5]. Reactive oxygen species (ROS) can damage the victim severely when the Cys level decreases [6]. Detection of both high and low levels of Cys is needed to investigate chronic illness like hemolytic anemia, motor neuron disease, depression, autism, irritable bowel syndrome, myalgic encephalomyelitis and multiple sclerosis. ...
A selective and sensitive detection of L-cysteine (Cys) is an important tool for various biological studies. Here, Au nanoparticles (NPs) were prepared by chemical reduction technique. The probe was developed to detect and quantify Cys in the presence of Cr3+ ions which acts as a cross linker. The citrate capped Au NPs probe was analyzed by UV-visible spectrophotometry, TEM, EDAX, FTIR, DLS, XPS and zetasize. The zeta potential and effective size of Au NPs were -41.22 mV and 12 nm, respectively. The Cys interaction with Au NPs showed drastic colour variation from red to purple and colourless with rapid response time of 1 min. The limit of detection (LOD) of Au NPs probe was as low as 0.012 nM. The TEM image of Au NPs after Cys interaction verified the aggregation that resulted in colour change. The XPS core level scans of Au 4f showed 0.3 eV red shift when Cyswas interacted. The Au NPs sensor is highly selective for Cys with excellent reproducibility. Acidic pH slightly favored Cys detection. Further, the probe was applied to estimate Cys quantity from milk, urine, blood and environmental augmented samples in the presence of other amino acids . The study suggests that the proposed Au NPs could detect Cys with high accuracy from various biological samples.
... GSH concentration in immune cells, in addition to acting as a scavenger of reactive oxygen species (ROS) is of paramount importance for these cells to carry out their proper functions. It has been reported that even transient GSH deprivation affect several functions of immune cells, such as lymphocyte proliferation (Hamilos et al., 1989;Dröge and Breitkreutz, 2000;Rodrigues and Percival, 2019). ...
Chronic obstructive pulmonary disease (COPD) is characterised by inflammatory and oxidative alterations in the
lung and extrapulmonary compartments, through involvement of the immune system. Several leukocyte functions
are health markers and good predictors of longevity, and high pro-inflammatory and oxidative states are
related to more aged profiles. Here, we aimed to investigate the aging rate in terms of immunosenescence in
COPD men with respect to healthy age-matched controls.
Several neutrophil (adherence, chemotaxis, phagocytosis, superoxide anion stimulated production) and
lymphocyte (adherence, chemotaxis, lymphoproliferation, natural killer activity) functions, cytokine concentrations
released in response to lipopolysaccharide (tumor necrosis factor-alpha, interleukin (IL)-6, IL-8, IL-10)
and redox parameters (intracellular glutathione content, basal superoxide anion level) were assessed in circulating
leukocytes of men with moderate and severe stages of COPD, and compared to healthy age-matched
volunteers. The biological age or aging rate in each participant was determined using the values of leukocyte
functions.
The results indicated impairment of immune functions in COPD patients, both in innate and adaptive immunity,
and higher pro-inflammatory and oxidative states in peripheral leukocytes than controls. In general,
these changes were more remarkable at the severe stage of airway obstruction. Importantly, COPD patients were
found to be aging at a faster rate than age-matched healthy counterparts.
... Intracellular concentrations of reduced glutathione are maintained at the highest (millimolar) levels suggesting its vital and multifaceted roles, not solely limited by antioxidant defense [20]. Glutathione possesses a plethora of functions essential for whole-body homeostasis including the detoxification of both xenobiotic and endogenous compounds as well as the maintenance of the mitochondrial redox environment, antiviral defense by fine-tuning the innate immune response to antiviral pathways, the regeneration of vitamins C and E and the regulation of cellular proliferation, apoptosis and protein folding [20,[111][112][113][114][115][116][117]. Glutathione deficiency is well known for increasing oxidative stress, a pathological condition capable of disturbing the redox state in the endoplasmic reticulum and disrupt disulfide bond formation, adaptively activating ER stress and unfolded protein response [118,119]. ...
The present study investigated whether type 2 diabetes (T2D) is associated with polymor-phisms of genes encoding glutathione-metabolizing enzymes such as glutathione synthetase (GSS) and gamma-glutamyl transferase 7 (GGT7). A total of 3198 unrelated Russian subjects including 1572 T2D patients and 1626 healthy subjects were enrolled. Single nucleotide polymorphisms (SNPs) of the GSS and GGT7 genes were genotyped using the MassArray-4 system. We found that the GSS and GGT7 gene polymorphisms alone and in combinations are associated with T2D risk regardless of sex, age, and body mass index, as well as correlated with plasma glutathione, hydrogen peroxide, and fasting blood glucose levels. Polymorphisms of GSS (rs13041792) and GGT7 (rs6119534 and rs11546155) genes were associated with the tissue-specific expression of genes involved in unfolded protein response and the regulation of proteostasis. Transcriptome-wide association analysis has shown that the pancreatic expression of some of these genes such as EDEM2, MYH7B, MAP1LC3A, and CPNE1 is linked to the genetic risk of T2D. A comprehensive analysis of the data allowed proposing a new hypothesis for the etiology of type 2 diabetes that endogenous glutathione deficiency might be a key condition responsible for the impaired folding of proinsulin which triggered an unfolded protein response, ultimately leading to beta-cell apoptosis and disease development.
This study aims to identify the risk factors associated with clinical outcomes and the proteomic changes in organs related to fatal SARS‐CoV‐2 infection within the super‐elderly population. This retrospective analysis included all elderly individuals with COVID‐19 admitted to the Second Medical Center of PLA General Hospital from December 2022 to January 2023. The follow‐up period ended on March 30, 2023. During this time, epidemiological, demographic, laboratory, and outcome data were analyzed descriptively. Proteomic sequencing was performed on super‐elderly patients who died from COVID‐19 at different stages of the disease. A total of 352 elderly COVID‐19 patients, with a mean age of 89.84 ± 8.54 years, were included in this study. During a median follow‐up period of 98 days, 79 patients died. Deceased patients were older and more likely to have cardiovascular and cerebrovascular diseases, with a lower prevalence of lipid‐lowering therapy. The number of deaths in the acute and post‐acute phases were 34 and 45, respectively. Proteomics data suggest that the immune systems of patients who died in the acute phase underwent a more rapid and severe onslaught. Patients in the post‐acute phase showed higher levels of viral genome replication and a more robust immune response. However, the over‐activation of the immune system led to systemic organ dysfunction. Effective management of comorbidities may improve the prognosis of COVID‐19 in super‐elderly patients. The continuous replication of the SARS‐CoV‐2 virus and its subsequent impact on the immune system are critical determinants of survival time in this demographic.
Although the association between certain occupational exposures and the development of autoimmune rheumatic disease was first described over a century ago, this association has only become more widely recognized in the past 10 years because of the use of high-silica-content engineered stone in construction and home renovation. There is now a substantial and growing body of evidence that occupational dust and chemical exposure, be it through mining, stonemasonry, building or other trades, increases the risk of various systemic autoimmune rheumatic diseases (SARDs) including rheumatoid arthritis and systemic sclerosis. Although the pathogenic mechanisms of silica-induced autoimmunity are not fully elucidated, it is thought that alveolar macrophage ingestion of silica and the ensuing phagosomal damage is an initiating event that ultimately leads to production of autoantibodies and immune-mediated tissue injury. The purportedly causal association between occupational exposure to chemicals, such as organic solvents, and an increased risk of SARDs is less frequently recognized compared with silica dust, and its immunopathogenesis is less well understood. An appreciation of the importance of occupational dust and chemical exposures in the development of SARDs has implications for workplace health and safety regulations and offers a unique opportunity to better understand autoimmune disease pathogenesis and implement preventative strategies.
Photodynamic therapy (PDT) involves the activation of photosensitizers (PSs) by visible laser light at the target site to catalyze the production of reactive oxygen species, resulting in tumor cell death and blood vessel closure. The efficacy of PDT depends on the PSs, the amount of oxygen, and the intensity of the excitation laser. PSs have been extensively researched, and great efforts have been made to develop an ideal photosensitizer. Chlorin-e6 is an FDA-approved second-generation PSs that has attracted widespread research interest in the medical field, especially with respect to antitumor and anti-inflammatory activity. Chlorin-e6 possesses the advantages of a large absorption coefficient, high strength, low residue in the body, and relatively high safety and thus has promising application prospects. Here we review the use of chlorin-e6 in PDT and discuss the prospects of further development of this technology.
Staying and climbing in high mountains (>2,500 m) involves changes in diet due to poor access to fresh food, lack of appetite, food poisoning, environmental conditions and physiological changes. The purpose of this review is to summarize the current knowledge on the principles of nutrition, hydration and supplementation in high-altitude conditions and to propose practical recommendations/solutions based on scientific literature data. Databases such as Pubmed, Scopus, ScienceDirect and Google Scholar were searched to find studies published from 2000 to 2023 considering articles that were randomized, double-blind, placebo-controlled trials, narrative review articles, systematic reviews and meta-analyses. The manuscript provides recommendations for energy supply, dietary macronutrients and micronutrients, hydration, as well as supplementation recommendations and practical tips for mountaineers. In view of the difficulties of being in high mountains and practicing alpine climbing, as described in the review, it is important to increase athletes' awareness of nutrition and supplementation in order to improve well-being, physical performance and increase the chance of achieving a mountain goal, and to provide the appropriate dietary care necessary to educate mountaineers and personalize recommendations to the needs of the individual.
Radiation-induced lung injury (RILI) is a dose-limiting toxicity for cancer patients receiving thoracic radiotherapy. As such, it is important to characterize metabolic associations with the early and late stages of...
Background:
Allergic diseases affect about 10-30% of the population in low- or middle-income tropical countries. Few studies describe the factors associated with allergic diseases in adult patients undergoing immunotherapy in Latin American countries.
Objective:
This study aimed to determine the factors associated with allergic rhinitis (AR) and AR in comorbidity with asthma (CARAS) in adults treated with immunotherapy in two allergy referral centers in Bogotá (Colombia).
Material and methods:
Observational, cross-sectional study conducted between January 2018 and January 2019. ISAAC-III and sociodemographic questionnaires were applied to determine the factors associated with AR and CARAS in adults treated with immunotherapy who attended the allergy consult at the Fundación Santa Fe de Bogotá and Unimeq-Orl.
Results:
Among 416 adults aged 18-68 years, 71.4% (n = 297) were women. Regarding the sensitization results obtained by skin prick test, the most frequent allergens were house dust mites (64.18%): 49.03% were positive for both Dermatophagoides pteronyssinus and Dermatophagoides farinae, while 28.61% were positive for Blomia tropicalis. Excluding house dust mites, the most frequent allergens were dog hair (31.01%), cat hair (15.1%), grasses (15.9%), and food (15.9%). The main factor associated with exclusive AR was regular acetaminophen use more than four times a year: Prevalence ratio (PR) = 1.77 (95% CI: 1.12-2.25). The main factor associated with CARAS was cesarean delivery PR: 1.44 (95% CI: 1.09-1.78).
Conclusion:
The main factor associated with AR was regular acetaminophen use, while that associated with CARAS was cesarean delivery. The ISAAC-III questionnaire can be a useful low-cost tool to assess the factors associated with allergic diseases in adults in tropical countries.
COVID-19 has become the first modern-day pandemic of historic proportion, affecting >600 million individuals worldwide and causing >6.5 million deaths. While acute infection has had devastating consequences, postacute sequelae of SARS-CoV-2 infection appears to be a pandemic of its own, impacting up to one-third of survivors and often causing symptoms suggestive of cardiovascular phenomena. This review will highlight the suspected pathophysiology of postacute sequelae of SARS-CoV-2, its influence on the cardiovascular system, and potential treatment strategies.
In recent years, there has been a great deal of attention toward the field of free radical chemistry. Free radicals reactive oxygen species and reactive nitrogen species are generated by our body by various endogenous systems, exposure to different physiochemical conditions or pathological states. A balance between free radicals and antioxidants is necessary for proper physiological function. If free radicals overwhelm the body’s ability to regulate them, a condition known as oxidative stress ensues. Free radicals thus adversely alter lipids, proteins, and DNA and trigger a number of human diseases. This study was designed to determine the influence of Glutathione to reduce the pathological changes induced by estrogen. In this study 40 female and male mice are taken at age of 21days with groups of control (10 mouse in each group).The group of experimental animals was treated with estrogen and glutathione diluted with distilled water, as a vehicle, and injected intraperitonially for 12 weeks, once weekly. Each control group was injected with the vehicle of it in the same manner of injection and for the same period.
Background:
Despite the crucial role of educators in encourage students' academic learning, addressing educator stress inside the classroom remains a significant challenge in the educational context. Mindfulness Meditation training (MM) has been recommended as an environmental enrichment strategy in schools to help teachers cope with stress and cultivating a state of awareness in daily life. Although studies have shown that MM can improve immune system dynamics the biological mechanism underlying glutathione metabolism in a healthy human is unclear.
Objective:
The purpose of this study was to determine whether MM training benefits psychological and behavioral response, immunological functions and glutathione metabolism in service healthy female teachers from public schools.
Methods:
We randomly assigned 76 teachers to an 8-week Mindfulness-Based Health Program for Educators (MBHPEduca) or Neuroscience for Education program (Neuro-Educa; active control group). Using the quality of life as our primary outcome, perceived stress, negative affectivity, and resilience as our secondary outcome, and pro-inflammatory cytokines and glutathione levels as our third outcome at baseline and post-intervention that occurred in public schools. Blood samples were collected for the measurement of three proinflammatory markers, including interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-8 (IL-8) and three GSH metabolism, including Cysteine (Cys), Homocysteine (HCys) and GSH were conducted at pre-and post-intervention, with selfreported assessments over time. Treatment effects were analyzed using generalized estimating equations (GEE) with to intention to treat.
Results:
We observed statistically significant improvements to the MBHP-Educa group compared to active control in perceived stress, resilience, positive and negative affect, and quality of life after 8-weeks MM (p < 0.0001). Further, the MBHP-Educa group exhibited lower circulating IL-6 production accompanied by high circulating GSH, and Cys (p < 0.0001). Additional analyses indicated that enhancing quality of life through mindfulness meditation training was mediated by reducing perceived stress and serum levels of IL- 6 and increasing resilience and teachers 'plasma GSH levels.
Conclusions:
The present study is a pilot trial with low-power and provides preliminary evidence that mindfulness meditation training help teachers to cope with stress in the school environment with an impact on the quality of life, immune function, and glutathione metabolism.
The incidence of autoimmunity is growing rapidly worldwide. Many epidemiological studies have found environmental factors, such as toxic chemicals (persistent organic pollutants, toxic metals, solvents, endocrine disruptors), to be a key factor in this rapid progression. Numerous mechanisms have been identified that can cause immune dysregulation and autoimmune reactivity from toxic chemical exposure to subsets of individuals who have genetic susceptibility in immune regulatory genes. In susceptible genotypes, toxic chemicals can induce epigenetic expressions, bind to immune and endocrine receptors throughout the body and promote immune dysregulation, bind to nucleic acids and promote anti-nuclear autoimmunity, deplete antioxidant reserves, promote immune barrier degradation, induce lymphocyte dysregulation, and alter normal antigen-presenting responses. This paper provides a detailed review of the specific immunological pathways involved with exposure to environmental toxins and autoimmunity.
Objective: The research was aimed to determine the effects of glutathione extracts and some biological agents on immune and oxidative stress parameters in male rats induced Immunosuppression used Sandimmune. Methods: Glutathione was extract from spinach leaves and estimated the concentration used a high-performance liquid chromatography (HPLC) and determined the effect of orally dosage at one mg/ml alone or with both Zinc or Vit C or cell concentration of Lactobacillus plantarum (CCLP) on the immunity and biological parameters of male rats induced Immunosuppression used Sandimmune and breeding for 28 days. Results: The results indicated that aqueous spinach extract was contained glutathione at a concentration of 246 µg/g in the case of extraction using aqueous extract. The Immunosuppression induced was significantly (p<0.05) decreased of IgA, IgG and IgM values and became at 1022, 2031 and 121.5 mg/dl respectively compared with the control rats group which at 1564, 3206 and 174.7 mg/dl respectively while the orally dosage from biological parameters was caused in amelioration of immunity parameters to became similar of values with the control rats group. Also the oxidative stress parameters value as GSH, GPx, SOD and catalase enzyme were significantly decreased to 222, 0.17, 375 and 0.31µmol/L respectively and increased in MDA value to 4.6 µmol/L compared with the rats in control group, and the used of glutathione alone or with the biological parameters were done improvement to similar values in control group. Conclusion: It was concluded that oral dosage of glutathione alone or with biological agents was significantly effective in improving immunity and decreasing the oxidative stress values in the laboratory rats that induced immunosuppression. Abdel-Hamid ZD, Thalij KM (2020) The effects of oral dosage of glutathione and some biological agents on immunity and oxidative stress parameters in male rats induced with immunosuppression.
Maintenance of intracellular glutathione (GSH) levels has been implicated in blocking cytokine-stimulated HIV replication in vitro, in both acute and latent infection models. We demonstrate here that subsets of human peripheral blood mononuclear cells differ substantially in mean GSH levels, as measured on a cell-by-cell basis with the fluorescence-activated cell sorter (FACS): B cells have the lowest GSH levels; T cells are intermediate; and monocytes and macrophages have the highest levels. Furthermore, GSH levels subdivide the CD4 and CD8 T cell subsets into two classes each: high- and low-GSH cells, which cannot be distinguished by cell size or by currently known surface markers. Significantly, the high-GSH T cells are selectively depleted early during the HIV infection, and are effectively missing in all ARC and AIDS patients.
HIV-1 proviral DNA contains two binding sites for the transcription factor NF-kappa B. HIV-1-infected individuals have, on average, abnormally high levels of tumour necrosis factor alpha (TNF alpha) and abnormally low plasma cysteine levels. We therefore investigated the effects of cysteine and related thiols on HIV-1 replication and NF-kappa B expression. The experiments in this report show that cysteine or N-acetylcysteine (NAC) raise the intracellular glutathione (GSH) level and inhibit HIV-1 replication in persistently infected Molt-4 and U937 cells. However, inhibition of HIV-1 replication appears not to be directly correlated with GSH levels. Cysteine and NAC also inhibit NF-kappa B activity as determined by electrophoretic mobility shift assays and chloramphenicol acetyl-transferase (CAT) gene expression under control of NF-kappa B binding sites in uninfected cells. This suggests that the cysteine deficiency in HIV-1-infected individuals may cause an over-expression of NF-kappa B-dependent genes and enhance HIV-1 replication. NAC may be considered for the treatment of HIV-1-infected individuals.
Hydrogen peroxide and oxygen radicals are agents commonly produced during inflammatory processes. In this study, we show that micromolar concentrations of H2O2 can induce the expression and replication of HIV-1 in a human T cell line. The effect is mediated by the NF-kappa B transcription factor which is potently and rapidly activated by an H2O2 treatment of cells from its inactive cytoplasmic form. N-acetyl-L-cysteine (NAC), a well characterized antioxidant which counteracts the effects of reactive oxygen intermediates (ROI) in living cells, prevented the activation of NF-kappa B by H2O2. NAC and other thiol compounds also blocked the activation of NF-kappa B by cycloheximide, double-stranded RNA, calcium ionophore, TNF-alpha, active phorbol ester, interleukin-1, lipopolysaccharide and lectin. This suggests that diverse agents thought to activate NF-kappa B by distinct intracellular pathways might all act through a common mechanism involving the synthesis of ROI. ROI appear to serve as messengers mediating directly or indirectly the release of the inhibitory subunit I kappa B from NF-kappa B.
Activation of the CD28 surface receptor provides a major costimulatory signal for T cell activation resulting in enhanced production of interleukin-2 (IL-2) and cell proliferation. In primary T lymphocytes we show that CD28 ligation leads to the rapid intracellular formation of reactive oxygen intermediates (ROIs) which are required for CD28-mediated activation of the NF-kappa B/CD28-responsive complex and IL-2 expression. Delineation of the CD28 signaling cascade was found to involve protein tyrosine kinase activity, followed by the activation of phospholipase A2 and 5-lipoxygenase. Our data suggest that lipoxygenase metabolites activate ROI formation which then induce IL-2 expression via NF-kappa B activation. These findings should be useful for therapeutic strategies and the development of immunosuppressants targeting the CD28 costimulatory pathway.
Plasma concentrations of 21 amino acids were determined for 20 control subjects and 20 subjects infected with human immunodeficiency virus type 1 (HIV). Compared with the control subjects, the HIV-infected group had lower cystine, tryptophan, and methionine (decreased 67%, 52%, and 32%, respectively, P < 0.001 for each) and increased taurine (230%, P < 0.001) and lysine concentrations (30%, P < 0.001). Other amino acid concentrations changed modestly. Amounts of cystine, tryptophan, methionine, taurine, and lysine did not differ significantly between subgroups of HIV-infected subjects with > 200 (n = 6) or < 200 (n = 14) CD4+ lymphocytes per microliter, suggesting that the concentrations decrease soon after infection and change little thereafter. Activation of metabolism of cystine to taurine may explain reciprocal changes in these amino acids and known depletion of cystine and glutathione. The selective changes in amino acid profiles observed during HIV infection differ from those recognized for malnutrition or other pathological processes.
HIV-infected individuals and SIV-infected rhesus macaques have, on the average, decreased plasma cysteine and cystine concentrations and decreased intracellular glutathione levels. We show that the cysteine supply and the intracellular glutathione levels have a strong influence on the T cell system. A study of healthy human subjects revealed that persons with intracellular glutathione levels of 20-30 nmol/mg protein had significantly higher numbers of CD4+ T cells than persons with either lower or higher glutathione levels. Persons who moved during a 4-week observation period from the optimal to the suboptimal range (10-20 nmol/mg) experienced, on the average, a 30% decrease in CD4+ T cell numbers. This decrease was prevented by treatment with N-acetyl-cysteine (NAC). NAC caused this relative increase of CD4+ T cell numbers in spite of decreasing glutathione levels and not by increasing the glutathione level. Our studies suggest that the immune system may be exquisitely sensitive not only against a cysteine and glutathione deficiency but also against an excess of cysteine.
Even a moderate increase in the cellular cysteine supply elevates the intracellular glutathione (GSH) and glutathione disulfide (GSSG) levels and potentiates immunological functions of lymphocytes in vitro. At low GSSG levels, T cells cannot optimally activate the immunologically important transcription factor NF kappa B, whereas high GSSG levels inhibit the DNA binding activity of NF kappa B. The effects of GSSG are antagonized by reduced thioredoxin (TRX). As the protein tyrosine kinase activities p56lck and p59fyn are activated in intact cells by hydrogen peroxide, they are likely targets for GSSG action. These redox-regulated enzymes trigger signal cascades for NF kappa B activation and transduce signals from the T cell antigen receptor, from CD4 and CD8 molecules, and from the IL-2 receptor beta-chain. The effector phase of cytotoxic T cell responses and IL-2-dependent functions are inhibited even by a partial depletion of the intracellular GSH pool. As signal transduction is facilitated by prooxidant conditions, we propose that the well-known immunological consequences of GSH depletion ultimately may be results of the accompanying GSSG deficiency. As HIV-infected patients and SIV-infected rhesus macaques have, on the average, significantly decreased plasma cyst(e)ine and intracellular GSH levels, we also hypothesize that AIDS may be the consequence of a GSSG deficiency as well.
The transcription factors NF-kappa B and AP-1 have been implicated in the inducible expression of a variety of genes involved in responses to oxidative stress and cellular defense mechanisms. Here, we report that thioredoxin, an important cellular protein oxidoreductase with antioxidant activity, exerts different effects on the activation of NF-kappa B and AP-1. Transient expression or exogenous application of thioredoxin resulted in a dose-dependent inhibition of NF-kappa B activity, as demonstrated in gel shift and transactivation experiments. AP-1-dependent transactivation, in contrast was strongly enhanced by thioredoxin. A similar increase of AP-1 activity was also observed with other, structurally unrelated antioxidants such as pyrrolidine dithiocarbamate and butylated hydroxyanisole, indicating that the thioredoxin-induced increase of AP-1 activation was indeed based on an antioxidant effect. Moreover, the stimulatory effect on AP-1 activity was found to involve de novo transcription of the c-jun and c-fos components but to be independent of protein kinase C activation. These results suggest that thioredoxin plays an important role in the regulation of transcriptional processes and oppositely affects NF-kappa B and AP-1 activation.
We show that AP-1 is an antioxidant-responsive transcription factor. DNA binding and transactivation by AP-1 were induced in HeLa cells upon treatment with the antioxidants pyrrolidine dithiocarbamate (PDTC) and N-acetyl-L-cysteine (NAC), and upon transient expression of the antioxidative enzyme thioredoxin. While PDTC and NAC enhanced DNA binding and transactivation of AP-1 in response to phorbol ester, the oxidant H2O2 suppressed phorbol ester activation of the factor. H2O2 on its own was only a weak inducer of AP-1. Activation of AP-1 by PDTC was dependent on protein synthesis and involved transcriptional induction of c-jun and c-fos genes. Transcriptional activation of c-fos by PDTC was conferred by the serum response element, suggesting that serum response factor and associated proteins function as primary antioxidant-responsive transcription factors. In the same cell line, the oxidative stress-responsive transcription factor NF-kappa B behaved in a manner strikingly opposite to AP-1. DNA binding and transactivation by NF-kappa B were strongly activated by H2O2, while the antioxidants alone were ineffective. H2O2 potentiated the activation of NF-kappa B by phorbol ester, while PDTC and NAC suppressed PMA activation of the factor. PDTC did not influence protein kinase C (PKC) activity and PKC activation by PMA, indicating that the antioxidant acted downstream of and independently from PKC.
In a double-blind placebo-controlled trial, human immunodeficiency virus (HIV)-seropositive patients with a CD4 lymphocyte cell count of more than 200 x 10(6) . l-1 were randomised to receive either 800 mg N-acetylcysteine (NAC) or placebo for 4 months. Before treatment low plasma cysteine levels, high free radical activity in neutrophils in the presence of autologous plasma-measured by the nitroblue tetrazolium (NBT) test- and increased tumor necrosis factor (TNF)-alpha levels were found in the HIV positive patients.
After treatment the low plasma cysteine level in the NAC group increased to normal, and the decline of the CD4+ lymphocyte count before the study start, was less steep in the NAC group than in the placebo group after treatment. There was also a reduction in TNF-alpha level. However, NAC had no effect on the radical production by neutrophils, and although it did not increase the CD4+ cell count, it may have decreased the decline in CD4+ cells.
Further controlled trials with NAC are needed to determine whether it has a beneficial effect in the treatment of asymptomatic HIV-infected individuals.
Patients with skeletal muscle catabolism (cachexia) fail to conserve the skeletal muscle protein and release large amounts of nitrogen as urea. Previous studies suggest that the threshold for the conversion of amino acids into other forms of chemical energy and the concomitant production of urea are regulated by the plasma cystine level and hepatic cysteine catabolism. Studies of plasma amino acid exchange rates in the lower extremities now show that healthy young subjects regulate their plasma cystine level in a process that may be described as controlled constructive catabolism. The term controlled describes the fact that the release of cystine and other amino acids from the peripheral tissue is negatively correlated with (certain) plasma amino acid levels. The term constructive describes the fact that the release of cystine is correlated with an increase of the plasma cystine level. The regulation of the plasma cystine level is disturbed in conditions with progressive skeletal muscle catabolism including cancer, HIV infection, and old age. These conditions show also a low plasma glutamine:cystine ratio indicative of an impaired hepatic cystine catabolism. In HIV+ patients and SIV-infected macaques, a decrease of the plasma cystine level was found to coincide with the decrease of CD4+ T cells.
Growing evidence has indicated that cellular reduction/oxidation (redox) status regulates various aspects of cellular function. Oxidative stress can elicit positive responses such as cellular proliferation or activation, as well as negative responses such as growth inhibition or cell death. Cellular redox status is maintained by intracellular redox-regulating molecules, including thioredoxin (TRX). TRX is a small multifunctional protein that has a redox-active disulfide/dithiol within the conserved active site sequence: Cys-Gly-Pro-Cys. Adult T cell leukemia-derived factor (ADF), which we originally defined as an IL-2 receptor alpha-chain/Tac inducer produced by human T cell lymphotrophic virus-I (HTLV-I)-transformed T cells, has been identified as human TRX. TRX/ADF is a stress-inducible protein secreted from cells. TRX/ADF has both intracellular and extracellular functions as one of the key regulators of signaling in the cellular responses against various stresses. Extracellularly, TRX/ADF shows a cytoprotective activity against oxidative stress-induced apoptosis and a growth-promoting effect as an autocrine growth factor. Intracellularly, TRX/ADF is involved in the regulation of protein-protein or protein-nucleic acid interactions through the reduction/oxidation of protein cysteine residues. For example, TRX/ADF translocates from the cytosol into the nucleus by a variety of cellular stresses, to regulate the expression of various genes through the redox factor-1 (Ref-1)/APEX. Further studies to clarify the regulatory roles of TRX/ADF and its target molecules may elucidate the intracellular signaling pathways in the responses against various stresses. The concept of "redox regulation" is emerging as an understanding of the novel mechanisms in the pathogenesis of several disorders, including viral infections, immunodeficiency, malignant transformation, and degenerative disease.
Initial investigations demonstrated a deficiency of glutathione (GSH) in the epithelial lining fluid (ELF) of HIV-seropositive patients. In a recent study, our laboratory was unable to document such a deficiency. The current study was performed in an attempt to reconcile those disparate findings.
To determine if ELF GSH decreases over time in asymptomatic HIV-seropositive subjects.
Prospective, longitudinal study.
Major university medical center.
Thirty-three asymptomatic HIV-seropositive volunteers.
None.
BAL was performed on 33 asymptomatic HIV-seropositive subjects at baseline, 6 months later, and 12 months later. The volume of ELF and the concentration of GSH and oxidized GSH were determined. The concentration of total GSH in ELF was 689.0+/-100.4 microM. This significantly decreased when measured 6 and 12 months later (355.9+/-41.7 microM, and 397.9+/-52.7 microM, respectively, p=0.01, compared with baseline, both comparisons). Significant decreases were also noted in the HIV-seropositive subjects who smoked cigarettes (baseline--762.6+/-142.4 microM; 6 months--373.7+/-45.9 microM; 12 months--459.3+/-73.8 microM, p<0.03, for baseline vs 6 months, and baseline vs 12 months). In nonsmoking HIV-seropositive subjects, there was a decrease in ELF GSH over time, but it did not reach statistical significance (baseline--589.1+/-138.2 microM; 6 months--335.3+/-74.1 microM; 12 months--345.8+/-74.0 microM, p>0.1, all comparisons). The percentage of total GSH in the oxidized form was similar at all three time points (baseline--3.8+/-0.5%; 6 months--3.1+/-0.5%; 12 months--3.9+/-0.9%, p>0.1, all comparisons).
The current study demonstrates that the GSH level in ELF is significantly decreased in HIV-seropositive subjects 6 and 12 months after the initial determination.
We show that AP-1 is an antioxidant-responsive transcription factor. DNA binding and transactivation by AP-1 were induced in HeLa cells upon treatment with the antioxidants pyrrolidine dithiocarbamate (PDTC) and N-acetyl-L-cysteine (NAC), and upon transient expression of the antioxidative enzyme thioredoxin. While PDTC and NAC enhanced DNA binding and transactivation of AP-1 in response to phorbol ester, the oxidant H2O2 suppressed phorbol ester activation of the factor. H2O2 on its own was only a weak inducer of AP-1. Activation of AP-1 by PDTC was dependent on protein synthesis and involved transcriptional induction of c-jun and c-fos genes. Transcriptional activation of c-fos by PDTC was conferred by the serum response element, suggesting that serum response factor and associated proteins function as primary antioxidant-responsive transcription factors. In the same cell line, the oxidative stress-responsive transcription factor NF-kappa B behaved in a manner strikingly opposite to AP-1. DNA binding and transactivation by NF-kappa B were strongly activated by H2O2, while the antioxidants alone were ineffective. H2O2 potentiated the activation of NF-kappa B by phorbol ester, while PDTC and NAC suppressed PMA activation of the factor. PDTC did not influence protein kinase C (PKC) activity and PKC activation by PMA, indicating that the antioxidant acted downstream of and independently from PKC.
Activation of the CD28 surface receptor provides a major costimulatory signal for T cell activation resulting in enhanced production of interleukin‐2 (IL‐2) and cell proliferation. In primary T lymphocytes we show that CD28 ligation leads to the rapid intracellular formation of reactive oxygen intermediates (ROIs) which are required for CD28‐mediated activation of the NF‐kappa B/CD28‐responsive complex and IL‐2 expression. Delineation of the CD28 signaling cascade was found to involve protein tyrosine kinase activity, followed by the activation of phospholipase A2 and 5‐lipoxygenase. Our data suggest that lipoxygenase metabolites activate ROI formation which then induce IL‐2 expression via NF‐kappa B activation. These findings should be useful for therapeutic strategies and the development of immunosuppressants targeting the CD28 costimulatory pathway.
In studies on fatty livers due to amino acid imbalances, it was found that addition of 0.3% of methionine and threonine to a protein free diet significantly reduced the loss of body weight and urinary nitrogen excretion of young adult female rats. Addition of methionine alone or of a combination of methionine and an essential amino acid other than threonine had a little effect in reducing urinary nitrogen excretion. Supplemented amount and the ratio of methionine and threonine was also investigated and the nitrogen sparing action of methionine and threonine was observed in fairly wide range of the supplemented amount and the ratio of the two amino acids. Effect of supplementation of methionine and threonine on some amino acid catabolizing enzymes in the livers of rats was also investigated.
Purified CD4+ and CD8+ T cells, prepared from seven aged rhesus monkeys (>20 years), were 40-97% suppressed in their mitogenic responses to Con A or anti-CD3 (with PMA) when compared to T cell responses from four young control animals. The suppressed mitogenic responses were paralleled by diminished synthesis of interleukin-2 (IL-2). The CD4+ and CD8+ T cells from a given aged animal were suppressed approximately the same degree. Addition of NAC (5 mM) enhanced the aged T cell proliferative response and IL-2 production from 4-15 fold; the more strongly suppressed cells generally were more responsive to NAC Control T cell responses were modestly enhanced from 1.5-3 fold. Since the cysteine of NAC readily incorporates into glutathione, the observation that NAC restores aged T cell responses suggests that glutathioneassociated metabolism, an important component for T cell mitogenesis, may be altered in aged rhesus T cells. Supported by NIH grants 1-S06RR08239 and 1G12RR03050.
The nitrogen sparing action of methionine and arginine supplementations to a protein-free diet were studied with colostomized adult cocks.Body weight loss of the cocks fed a protein-free diet was alleviated with methionine or arginine supplementation, but neither effect was significant. Faecal nitrogen showed comparable values and urinary nitrogen of the cocks fed the methionine supplemented diet was the lowest of the 3 groups. The nitrogen balance were, in the order of increasing, methionine supplemented, arginine supplemented and protein-free groups.Each of the major urinary nitrogenous compounds of cocks fed the methionine supplemented diet showed lower values than the corresponding values for the cocks fed a protein-free diet. From the result of faecal nitrogen and faecal amino acid analysis, there was no evidence that the re-utilization of endogenous nitrogen of the birds fed a protein-free diet was enhanced by the addition of methionine or arginine.
To establish whether the low cysteine and glutathione levels in HIV-infected patients and SIV-infected rhesus macaques may be consequences of an abnormal cysteine catabolism, we analyzed sulfate and glutathione levels in macaques. Muscle tissue (m. vastus lateralis and m. gastrocnemius) of SIV-infected macaques (n = 25) had higher sulfate and lower glutathione and glutamate levels than that of uninfected controls (n = 9). Hepatic tissue, in contrast, showed decreased sulfate and glutathione disulfide (GSSG) levels, and increased γ-glutamylcysteine synthetase (γ-GCS) activity. These findings suggest drainage of the cysteine pool by increased cysteine catabolism in skeletal muscle tissue, and by increased hepatic glutathione biosynthesis. Cachectic macaques also showed increased urea levels and decreased glutamine/urea ratios in the liver, which are obviously related to the abnormal urea excretion and negative nitrogen balance commonly observed in cachexia. As urea production and net glutamine synthesis in the liver are strongly influenced by proton-generating processes, the abnormal hepatic urea production may be the direct consequence of the cysteine deficiency and the decreased catabolic conversion of cysteine into sulfate and protons in the liver.
To establish whether the low cysteine and glutathione levels in HIV-infected patients and SIV-infected rhesus macaques may be consequences of an abnormal cysteine catabolism, we analyzed sulfate and glutathione levels in macaques. Muscle tissue (m. vastus lateralis and m. gastrocnemius) of SIV-infected macaques (n = 25) had higher sulfate and lower glutathione and glutamate levels than that of uninfected controls (n = 9). Hepatic tissue, in contrast, showed decreased sulfate and glutathione disulfide (GSSG) levels, and increased γ-glutamylcysteine synthetase (γ-GCS) activity. These findings suggest drainage of the cysteine pool by increased cysteine catabolism in skeletal muscle tissue, and by increased hepatic glutathione biosynthesis. Cachectic macaques also showed increased urea levels and decreased glutamine/urea ratios in the liver, which are obviously related to the abnormal urea excretion and negative nitrogen balance commonly observed in cachexia. As urea production and net glutamine synthesis in the liver are strongly influenced by proton-generating processes, the abnormal hepatic urea production may be the direct consequence of the cysteine deficiency and the decreased catabolic conversion of cysteine into sulfate and protons in the liver.
HIV-1 proviral DNA contains two binding sites for the transcription factor NF-x B. HIV-1-infected individuals have, on average, abnormally high levels of tumour necrosis factor [alpha] (TNF[alpha]) and abnormally low plasma cysteine levels. We therefore investigated the effects of cysteine and related thiols on HIV-1 replication and NF-x B expression. The experiments in this report show that cysteine or N-acetylcysteine (NAC) raise the intracellular glutathione (GSH) level and inhibit HIV-1 replication in persistently infected Molt-4 and U937 cells. However, inhibition of HIV-1 replication appears not to be directly correlated with CSH levels. Cysteine and NAC also inhibit NF-x B activity as determined by electrophoretic mobility shift assays and chloramphenicol acetyl-transferase (CAT) gene expression under control of NF-x B binding sites in uninfected cells. This suggests that the cysteine deficiency in HIV-1-infected individuals may cause an over-expression of NF-x B-dependent genes and enhance HIV-1 replication. NAC may be considered for the treatment of HIV-1-infected individuals.
(C) Lippincott-Raven Publishers.
Three bioassays were conducted to determine the limiting order of amino acids for endogenous amino acid utilization in chicks fed a protein-free diet. The studies were conducted during the period 10 to 21 d posthatching. Experiment 1 was a deletion assay in which a protein-free basal diet was supplemented with an amino acid mixture containing methionine, cystine, threonine, arginine, phenylalanine and glutamine. Each amino acid, or methionine + cystine together, was then deleted singly from the amino acid mixture. Supplementing the protein-free basal diet with the amino acid mixture reduced weight loss. Deletion of methionine and cystine from the amino acid mixture increased (P < 0.05) weight loss. Deleting threonine from the amino acid mixture also resulted in weight loss that was intermediate between the amino acid-supplemented diet and the protein-free basal diet, indicating it was second limiting after sulfur amino acids. Experiments 2 and 3 were amino acid addition assays. Additions of methionine or cystine to the protein-free basal diet, either singly or in combination, resulted in lower rates of weight loss and protein depletion. Addition of threonine to the diet supplemented with methionine and cystine further reduced weight loss. These studies indicate that sulfur amino acids are the first-limiting amino acids for utilization of endogenous amino acids. However, our results clearly demonstrate that the primary need is for cystine, and not for methionine per se.
Cocks were fed a protein-free diet supplemented with methionine plus arginine or glutamic acid for 25 days to investigate the effect of these amino acids on fecal and urinary nitrogen excretion. Addition of either methionine plus arginine or glutamic acid did not change the fecal nitrogen excretion. Methionine plus arginine supplementation reduced the urniary nitrogen excretion compared to the protein-free diet, whereas glutamic acid supplementation increased it. The reduced urinary nitrogen excretion resulting from supplementation with methionine plus arginine was mostly accounted for by a reduction in uric acid excretion. In the methionine plus arginine group, free amino acid analysis showed that free glutamine and glutamic acid content significantly decreased in liver while no differences were found in plasma. Since glutamine may play an important role in the formation of uric acid for chickens, the reduced amount of free glutamine and glutamic acid in the liver of cocks fed the diet suplemented with methionine plus arginine might account for the reduced excretion of uric acid, and therefore for the nitrogen sparing action of methionine plus arginine in chickens fed a protein-free diet.
It was previously reported that methionine and threonine supplementation of a protein free diet had a greater nitrogen sparing action than methionine supplementation alone. Investigated in this study were (1) effects of depletion of labile body protein on the nitrogen sparing action of methionine and threonine supplementation of a protein free diet, (2) the effects of graded levels of methionine and threonine on urinary nitrogen excretion, (3) the effect of supplementation of other amino acids to the protein free diet plus methionine and threonine on the urinary excretion of nitrogen and (4) sex differences in the nitrogen sparing action of methionine and threonine supplementation of a protein free diet. After 10 days of feeding a protein free diet to deplete the body labile proteins, nitrogen excretion in urine of female rats was significantly reduced within the first 2 days of feeding a protein free diet supplemented with methionine and threonine. After 7 days of feeding a protein free diet supplemented with methionine and threonine, nitrogen excretion was reduced when even as little as 0.0188% of each amino acid was added. The supplementation of all essential amino acids to the protein free diet did not reduce the urinary excretion of nitrogen further than the supplementation of methionine and threonine, but improved the nitrogen balance slightly. The excretion of urinary nitrogen by female rats fed the protein free diet supplemented with small amounts (0.0188%) of methionine and threonine was significantly reduced after 7 to 14 days of feeding. In males, small amounts of methionine and threonine had no significant effect at either 7 or 14 days.
Markedly decreased plasma cystine and cysteine concentrations have been found in HIV-infected patients at all stages of the disease and in SIV-infected rhesus macaques. The elevated glutamate levels found in the same patients aggravate the cysteine deficiency by inhibiting the membrane transport activity for cystine. The intact immune system appears to require a delicate balance between pro-oxidant and antioxidant conditions, maintained by a limited and well-regulated supply of cysteine. This balance is obviously disturbed in HIV infection and may contribute to the pathogenesis of AIDS.
To determine whether a single oral dose of N-acetylcysteine corrects the deficiency of cysteine and glutathione in plasma and mononuclear cells of HIV-infected patients.
Pharmacokinetic and pharmacodynamic study.
Cysteine and glutathione were measured in plasma and peripheral blood mononuclear cells of patients at different stages of HIV infection before and after a single oral dose of N-acetylcysteine.
At baseline, the plasma concentrations of glutathione and cysteine were significantly lower in HIV-infected patients than in healthy controls. The intracellular concentration of glutathione correlated with the absolute CD4 lymphocyte counts: the concentration of glutathione in mononuclear cells was significantly lower in patients with more advanced immunodeficiency. A single oral dose of N-acetylcysteine increased the concentration of cysteine in plasma and mononuclear cells of HIV-infected patients. Four hours after N-acetylcysteine administration, intracellular glutathione concentrations in the patients were moderately higher than at baseline and at 2 h.
Oral N-acetylcysteine transiently increases the concentrations of cysteine and glutathione in mononuclear cells of patients with HIV infection. A sustained increase in intracellular cysteine may be necessary to normalize intracellular glutathione. This may be accomplished by repeat administration of N-acetylcysteine.
Even moderate variations of the extracellular cysteine concentration were previously shown to affect T cell functions in vitro despite high concentrations of cystine. We therefore analyzed the membrane transport activities of T cells for cysteine and cystine, and the role of low molecular weight thiol in T cell-mediated host responses against a T cell tumor in vivo. A series of T cell clones and tumors including the highly malignant lymphoma L5178Y ESb and its strongly immunogenic variant ESb-D was found to express extremely weak transport activity for cystine but strong transport activity for cysteine. However, not all cells showed the expected requirement for cysteine (or 2-mercaptoethanol (2-ME)) in the culture medium. One group of clones and tumors including the malignant ESb-lymphoma did not respond to changes of extracellular cystine concentrations and was strongly thiol dependent. This group released only little acid soluble thiol (cysteine) if grown in cystine-containing cultures. The other T cell lines, in contrast, were able to maintain high intracellular GSH levels and DNA synthesis activity in cystine-containing culture medium without cystein or 2-ME and released substantial amounts of thiol. This group included the immunogenic ESb-D line. Additional thiol-releasing ESb variants were obtained by culturing large numbers of L5178Y ESb tumor cells in cultures without cysteine or 2-ME. All of these ESb variants showed a significantly decreased tumorigenicity and some of them induced cytotoxic and protective host responses even against the malignant ESb parent tumor. Taken together, our experiments suggest that the host response against a tumor may be limited in certain cases by the failure of the stimulator (i.e., the tumor) cell to deliver sufficient amounts of cysteine to the responding T cells.
To establish whether the high plasma glutamate and low acid-soluble thiol (mainly cysteine) concentrations previously found in patients with HIV-1 infection are a consequence of the infection or a risk factor for its development, a closely related animal model, rhesus and fascicularis macaques infected with simian immunodeficiency virus (SIVmac251), was studied. The 23 infected macaques had significantly lower mean plasma thiol and higher glutamate concentrations than 18 uninfected controls (p less than 0.001). The changes were apparent by 1 week after infection. Thus, abnormal plasma glutamate and thiol concentrations are, at least in this model, a direct and early consequence of the retroviral infection.
The concentration of L-lactate in the blood plasma of higher vertebrates is about 1 mM but can be as high as 30 mM under certain physiological and pathological conditions or in the vicinity of glycolytically active cells including macrophages. Here we report that high but physiologically relevant concentrations of lactate increase the expression of interleukin 2 (IL 2)-specific mRNA and the production of IL 2 activity in cultures of mitogenically stimulated T cells. Lactate supports IL 2 production most effectively if added 0-8 h after T cell stimulation and only in cultures of CD4+ but not of CD8+ T cells. In contrast to the DNA synthesis activity in these cell cultures, IL 2 production is not augmented but rather inhibited by exogenous glutathione (GSH). Lactate causes a reduction of intracellular GSH levels, and lactate-containing cultures require accordingly higher extracellular cysteine concentrations than control cultures to achieve similar intracellular GSH levels. In view of the strong variations of extracellular lactate concentrations in vivo, our experiments suggest that lactate may be part of a previously unknown mechanism by which the metabolic microenvironment modulates gene expression in T cells.
Glutathione (GSH) is known to play an important role in various lymphocyte functions. We now report that different T cell subsets express different requirements for intracellular GSH. Depletion of intracellular GSH by buthionine sulfoximine (BSO), a specific inhibitor of GSH biosynthesis, decreases the proportion of CD8+ cells (i.e., increases the CD4+/CD8+ ratio), and inhibits particularly the generation of large blast-like CD8+ cells and cytotoxic T lymphocyte (CTL) activity. CTL activity is restored by administration of exogenous GSH. Differential effects of GSH depletion were also seen at the level of individual T cell clones. The CD4+ helper T cell clone D10.G4.1.HD was found to express a high rate of interleukin 2 (IL-2) dependent DNA synthesis even after severe depletion of intracellular GSH, whereas other T cell clones including the clone 29 were severely inhibited by BSO. The results of these studies suggest that the decreased intracellular GSH levels of HIV-1 seropositive persons are probably not (directly) responsible for the selective depletion of the CD4+ T cell subset but may be responsible for a cellular dysfunction of the CD8+ subset and for the ultimate failure of the CTL to control the viral infection in these patients.
The stimulation of DNA synthesis in lymphocyte populations was previously shown to depend strongly on the intracellular glutathione (GSH) level. Since T cell growth is known to depend on interleukin 2 (IL-2), the experiments in this report were designed to determine whether intracellular GSH depletion may inhibit IL-2 production or the IL-2 dependent DNA synthesis. Our experiments revealed that IL-2 production and DNA synthesis of mitogenically stimulated splenic T cells have indeed different requirements for GSH. The addition of relatively high concentrations of GSH (5 mM) to cultures of concanavalin A (Con A)-stimulated splenic T cells was found to augment strongly the DNA synthesis but inhibited the production of IL-2. Moderate intracellular GSH levels, however, are apparently not inhibitory for IL-2 production, since intracellular GSH depletion by cysteine starvation or by graded concentrations of DL-buthionine sulfoximine (BSO) had virtually no effect on IL-2-specific mRNA expression and the production of T cell growth factor (TCGF). The DNA synthesis activity, in contrast, was strongly suppressed after GSH depletion with either method. As in cultures of splenic T cells, GSH depletion had no substantial effect on the induction of IL-2 mRNA and TCGF production in several mitogenically stimulated T cell clones. Taken together, our experiments suggest that complex immune response may operate best at intermediate GSH levels that are not too high to inhibit IL-2 production but sufficient to support DNA synthesis.
Macrophages consume cystine and generate approximately equivalent amounts of acid-soluble thiol. Stimulation of macrophages with bacterial lipopolysaccharide (LPS) or tumor necrosis factor (TNF) strongly augments the amount of thiol released into the culture supernatant. Cysteine constitutes most of the acid-soluble thiol. The intracellular glutathione level and the DNA synthesis activity in mitogenically stimulated lymphocytes are strongly increased by either exogenously added cysteine, or (syngeneic) macrophages. This cysteine dependency is observed even in the presence of relatively high extracellular cystine concentration as they occur in the blood plasma. The extracellular cysteine concentration also has a strong influence on the intracellular glutathione concentration, viability, and DNA synthesis of cycling T cell clones. Moreover, the cysteine concentration in the culture medium on Day 3 and Day 4 of a 5-day allogeneic mixed lymphocyte culture (i.e., in the late phase of incubation) has a strong influence on the generation of cytotoxic T cell activity, indicating that regulatory effects of cysteine are not restricted to the early phase of the blastogenic response. The inhibitory effect of cysteine starvation on the DNA synthesis of the T cell clones and on the activation of cytotoxic T lymphocytes can be explained essentially by the depletion of intracellular glutathione, since similar effects are observed after treatment with buthionine sulfoximine (BSO), a specific inhibitor of the glutathione biosynthesis. BSO has practically no influence, however, on the N alpha-benzyloxycarbonyl Ne-t-butyloxycarbonyl-L-lysine-thiobenzyl-ester (BLT)-esterase activity and hemolytic activity of the cell lysates from cytotoxic T cells against sheep red blood cells (perforin activity). Taken together, our experiments indicate that cysteine has a regulatory role in the immune system analogous to the hormone-like lymphokines and cytokines. It is released by macrophages at a variable and regulated rate and regulates immunologically relevant functions of lymphocytes in the vicinity.
To find out whether systemic glutathione deficiency is associated with human immunodeficiency virus (HIV) infection, thus contributing to the immunodeficiency state, glutathione concentrations in venous plasma and lung epithelial lining fluid (ELF) of symptom-free HIV-seropositive and normal individuals were measured. Total and reduced glutathione concentrations in the plasma of the HIV-infected subjects were about 30% of those in the normal individuals. Concentrations of these substances in the ELF of HIV-infected subjects were about 60% of those in the controls. There was no correlation between ELF and plasma concentrations of total or reduced glutathione. Since glutathione enhances immune function, glutathione deficiency may contribute to the progressive immune dysfunction of HIV infection.
Blood plasma samples from HIV-1-infected persons contain elevated glutamate concentrations up to 6-fold the normal level and relatively low concentrations of acid-soluble thiol (i.e. decreased cysteine concentrations). The intracellular glutathione concentration in peripheral blood-mononuclear cells (PBMC) and monocytes from HIV antibody-positive persons are also significantly decreased. Therapy with azidothymidine (AZT) causes a substantial recovery of the plasma thiol levels; but glutamate levels remain significantly elevated and intracellular glutathione levels remain low. Cell culture experiments with approximately physiological amino-acid concentrations revealed that variations of the extracellular cysteine concentration have a strong influence on the intracellular glutathione level and the rate of DNA synthesis [( 3H]thymidine incorporation) in T cell clones and human and murine lymphocyte preparations even in the presence of several-fold higher cystine and methionine concentrations. Cysteine cannot be replaced by a corresponding increase of the extracellular cystine or methionine concentration. These experiments suggest strongly that the low cysteine concentration in the plasma of HIV-infected persons may play a role in the pathogenetic mechanism of the acquired immunodeficiency syndrome.
The acquired immunodeficiency syndrome (AIDS) is accompanied by a metabolic disturbance. Serum samples from persons with antibodies against the AIDS associated human immunodeficiency virus (HIV/LAV/HTLV III) including persons without overt symptoms, patients with lymphadenopathy syndrome (LAS) and patients with AIDS or AIDS-related complex (ARC) contain on the average significantly elevated concentrations of arginine and glutamate. The serum from patients with overt AIDS contains also, on the average, significantly reduced concentrations of methionine and cystine. In vitro experiments revealed that the [3H]thymidine incorporation by mitogenically stimulated murine lymphocytes and cloned T cells is inhibited by an elevation of the extracellular glutamate concentration and augmented by the addition of cysteine. This suggests the possibility that the abnormal concentrations of glutamate and cystine in the blood of HIV-infected persons may contribute to the defect in the lymphoid system.
Activated macrophages are known to release a variety of immunoregulatory substances including the low-molecular-weight substances hydrogen peroxide and lactate. We report here that lactate but not hydrogen peroxide is capable of supporting a substantial production of T-cell growth factor (TCGF) in cultures of accessory cell-depleted splenic T-cell populations after stimulation with concanavalin A. Hydrogen peroxide and its biosynthetic precursor superoxide anion (O2-) mediate, however, a strong augmentation of the TCGF production by accessory cell-depleted T-cell populations in the presence of lactate. Lactate inhibits the incorporation of [3H]thymidine in short-term cultures (18-26 hr) of accessory cell-depleted T cells. This confirms the rule that (optimal) production of T-cell growth factor requires a growth inhibitory signal. Concentrations of hydrogen peroxide which augment TCGF production most effectively (i.e., 1 X 10(-5) M) do not inhibit the incorporation of [3H]thymidine; and higher concentrations (3 X 10(-5)-1 X 10(-4) M) of hydrogen peroxide inhibit both the production of TCGF and the incorporation of [3H]thymidine. In agreement with the augmenting effect of hydrogen peroxide on TCGF production, it was observed that the proliferative response in mixed lymphocyte cultures is suppressed by catalase and augmented by 1 X 10(-5) M H2O2. Proliferative and cytotoxic responses in mixed lymphocyte cultures with an external source of interleukin 2 (IL-2) in contrast, are not augmented by 1 X 10(-5) M H2O2. The relatively high concentration of 1 X 10(-4) M hydrogen peroxide was found to inhibit the proliferative responses in mixed lymphocyte cultures with or without external IL-2 but not the cytotoxic response in the presence of IL-2. This indicates that CTL precursor cells may be relatively resistant against H2O2.
Cysteine and cystine transport activities of resting and activated mouse spleen lymphocytes were characterized in order to examine the contributions of cysteine and cystine to intracellular glutathione contents. Following stimulation with lipopolysaccharide, the lymphocytes markedly increased their capacity to transport cysteine. The uptake of cysteine was mediated mainly by the ASC system (Na+-dependent neutral amino acid transport system especially reactive with alanine, serine, and cysteine). On the other hand, both the resting and the activated lymphocytes had extremely low cystine transport activities. Because of the instability of cysteine, the culture media usually contained cystine but not cysteine. Therefore, both the resting and the activated lymphocytes rapidly decreased their glutathione contents owing to their poor capacities to take up cystine. The effects of freshly added cysteine on the cellular glutathione contents were examined in the presence of bathocuproinedisulfonate, a nontoxic copper-specific chelator that inhibits autoxidation of cysteine. Cysteine added at 25-400 microM only partially prevented the rapid decrease of the glutathione contents in fresh resting lymphocytes. In the lipopolysaccharide-activated cells, however, cysteine enhanced the cellular glutathione contents in a dose-dependent manner. These results indicate that the enhanced activity of the ASC system increases the level of intracellular glutathione in the presence of cysteine.
The role of glutathione (GSH) in lectin-induced lymphocyte activation can be studied by quantitating lectin-induced nuclear size transformation in the presence of variable degrees of GSH depletion. Buthionine sulfoximine (BSO) inhibits intracellular GSH synthesis by inhibition of the enzyme gamma-glutamyl-cysteine synthetase. By combining endogenous GSH depletion in cell cultures with BSO-induced inhibition of GSH synthesis, lectin-induced lymphocyte activation can be studied at various concentrations of soluble intracellular GSH. With this approach, the percentage of lymphocytes undergoing a nuclear size transformation is minimally affected despite depletion of soluble intracellular GSH to 0.27 nmol/107 cells (PBL), which represents approximately 95% depletion of intracellular GSH. When soluble intracellular GSH is depleted to undetectable levels (less than 0.10 nmol/10(7) cells) there is a 10 to 12% reduction in the number of cell nuclei transformed. However, in all BSO-pretreated cultures the lectin-induced nuclear size transformation is intermediate between resting and blast-transformed lymphocytes, suggesting only partial (or aborted) activation.
The partial activation response observed in BSO-pretreated cultures may be due to mobilization of the protein-bound pool of GSH, which is relatively resistant to depletion by BSO. That the inhibition of full blast transformation is truly due to GSH depletion was proven by experiments in which GSH was repleted exogenously and a full blast transformation was restored.
The results of previous work in our laboratory had shown that the sulfhydryl-reactive agent 2-cyclohexene-1-one (2-CHX) was a potent inhibitor of activation at soluble intracellular GSH concentrations well above 0.27 nmol/107 PBL. In the present study, the dose-dependent inhibition of activation by 2-CHX was confirmed, but it was shown that the degree of inhibition caused by 2-CHX could be at least partially dissociated from the level of intracellular GSH present at the time of lectin addition and that the inhibitory potential of 2-CHX exceeded that of BSO at comparable levels of soluble intracellular GSH. Thus, the inhibitory properties of 2-CHX cannot be accounted for solely on the basis of GSH depletion.
Der Einfluß einer Methionin-Ergänzung zu einer eiweißfreien Ration auf die Stickstoffausscheidung bei Ratten und Schweinen
1. Sechs Gruppen von je 8 männlichen Albino-Ratten im Alter von 3 Monaten und von 260 bis 300 g Körpergewicht (KG) wurden während einer Vorversuchsperiode von 18 Tagen mit Rationen gefüttert, die Weizengluten oder mit Methionin angereichertes Kasein als einzige Eiweißquelle enthielten. Drei Eiweißniveaus wurden angewendet. Die N-Bilanz, bestimmt während der letzten 4 Tage der Vorversuchs-periode, betrug durchschnittlich -22, 98 und 229 mg N/kg KG0,75 entsprechend in den Gruppen mit niedrigem, mittlerem und hohem Eiweißniveau.
2. Jede Gruppe wurde anschließend in 2 Untergruppen eingeteilt, die während der 12 Tage langen Versuchsperiode mit einer eiweißfreien Ration, mit oder ohne Zusatz von 11 mg Methionin pro Tag und Tier, gefüttert wurden. Harn und Faeces wurden von jedem Tier gesondert gesammelt und der Gehalt an Gesamt-, Harnstoff- und Kreatinin-N bestimmt.
3. Die N-Ausscheidung in den Faeces war höher bei Ratten, die mit höheren Eiweißgaben vorgefüttert waren. Sie ging stufenweise zurück und war unabhängig von der Art des vorgefütterten Eiweißes und dem Methionin-Zusatz.
4. Der Methionin-Zusatz hatte keinen Einfluß auf die N-Ausscheidung im Harn von mit niedrigerem Eiweißniveau vorgefütterten Ratten, dagegen beeinflußte er significant die renale Ausscheidung von Gesamt- und Harnstoff-N in Gruppen, die mit mittlerem oder hohem Eiweißniveau vorgefüttert waren. Die Körpergewichtsverluste in diesen Gruppen wurden auch durch Methionin-Zusatz significant herabgesetzt. Daraus ist zu schließen, daß der Methionin-Zusatz zum eiweißfreien Futter die N-Ausscheidung im Harn nur bei Tieren mit nicht erschöpften Reserven von labilem Eiweiß herabsetzt und daß diese Wirkung mit der Resynthese dieser Reserven zusammenhängt.
5. In einem Vorversuch mit 4 bis 5 Monate alten Schweinen (Kastraten), die mit hohen Eiweißgaben gefüttert wurden, setzte auch ein Methionin-Zusatz (4 g täglich für Schweine von 76 kg Gewicht) die N-Ausscheidung im Harn significant herab.
6. Die Ausscheidung von Kreatinin-N bei Ratten war gleichmäßig und unabhängig von der vorgefütterten Futterration. Weder bei Ratten noch bei Schweinen wurde sie durch Methionin-Zusatz beeinflußt und war proportional zum jeweiligen Lebendgewicht (etwa 15 mg N/kg) nicht aber zu seiner Bruchpotenz.
Lymphocytes may be stimulated to undergo transformation into blast cells by a variety of nonspecific chemical agents, or by antiglobulin or antilymphocyte antisera. Antigens act as mitogenic agents on lymphocytes from sensitized animals (1-3).
We have now observed that the action of various mitogens on human and rabbit peripheral lymphoeytes is markedly enhsnced in the presence of the reducing agents, l-cysteine, glutathione, or sulfite.
Rabbit peripheral lymphocytes were isolated, purified on a cotton-wool column and cultured as described previously (4). Human leukocytes were obtained from the blood of normal individuals by allowing the cells to settle in 10% Plasmagel (Laboratoire Roger Bellon, Neuilly, France). The leukocyte-rich layer was removed and the cells were washed several times with 20% decomplemented fetal calf serum in Eagle's minimal essential medium (MEM). Leukocytes were cultured (4) at a concentration of 106 cells/ml. Rabbit lymphoeytes were cultured for 48 hr and human leukocytes for 108 hr; 24 hr before harvest, 5 µCi of 3H-thymidine (6.7 Ci/mM) was added to the rabbit lymphocyte cultures and either 5 µCi or 2 µCi of 3H-thymidine to the human leukocyte cultures. Radioactivity incorporated into DNA was determined as described previously (4).
This review is concerned with current progress in unraveling the biochemical bases of the physiological roles of this important compound. Detailed information is now available about glutathione synthesis and its metabolism by the reactions of the γ-glutamyl cycle, and its function in reductive processes that are essential for the synthesis (and the degradation) of proteins, formation of the deoxyribonucleotide precursors of DNA, regulation of enzymes, and protection of the cell against reactive oxygen compounds and free radicals. In addition, glutathione is a coenzyme for several reactions; it conjugates with foreign compounds (e.g. drugs) and with compounds formed in metabolism (e.g. estrogens, prostaglandins, leukotrienes), and thus participates in their metabolism. An important recent finding is that cellular turnover of glutathione is associated with its transport, in the form of GSH, out of cells. The functions of such GSH transport include formation by membrane-bound γ-glutamyl transpeptidase of γ-glutamyl amino acids, which can be transported into certain cells, and thus serve as one mechanism of amino acid transport. Transported GSH probably also functions in reductive reactions that may involve the cell membrane and the immediate environment of the cell. In the mammal, such transported GSH may enter the blood plasma and be transferred to other cells. Glutathione thus appears to be a storage form and a transport form of cysteine. Much of the new information about glutathione has arisen through studies with selective inhibitors of the enzymes involved in its metabolism. Thus, inhibition in vivo of γ-glutamyltranspeptidase, γ-glutamyl cyclotransferase, 5-oxoprolinase, and glutathione synthesis has been achieved, and the effects observed have contributed importantly to the understanding of glutathione metabolism and function. Studies on the inhibition of γ-glutamyl transpeptidase have elucidated the transport of GSH and the formation and transport of γ-glutamyl amino acids. Inhibition of glutathione synthesis by sulfoximine compounds that inactivate γ-glutamylcysteine synthetase has also contributed to such knowledge, as well as to information about the roles of glutathione in protection against both free radicals and reactive oxygen compounds, and in metabolism. These enzyme inhibitors, and other compounds that increase in vivo glutathione synthesis have opened the way to selective modulation of glutathione metabolism; this has made several new therapeutic approaches possible.
Glutathione, a tripeptide thiol found in virtually all cells, functions in metabolism, transport, and cellular protection.
It participates in the reduction of disulfides and other molecules, and conjugates with compounds of exogenous and endogenous
origin. It protects cells against the destructive effects of reactive oxygen intermediates and free radicals. Modifications
of glutathione metabolism may be achieved by administration of selective enzyme inhibitors, and also by giving compounds that
increase glutathione synthesis. Such effects are useful in chemotherapy and radiation therapy and in protecting cells against
the toxic effects of drugs, other foreign compounds, and oxygen.
"Professional" antigen-presenting cells (APC) such as macrophages or dendritic cells display not only antigens to specific T cell receptors but deliver in addition certain "costimulatory signals." Macrophages also release substantial amounts of cysteine and raise thereby the intracellular glutathione (GSH) levels of activated T cells in their vicinity. We therefore studied the hypothesis that stimulation with "nonprofessional" APC that fail to deliver cysteine may induce a type of immunological unresponsiveness that is caused by GSH deficiency and prevented by administration of exogenous GSH. Our experiments showed that cytotoxic T cell (CTL) responses are indeed strongly suppressed in vivo and in vitro by different types of nonprofessional APC and reconstituted by administration of GSH at the time of immunization if these APC are administered at relatively high doses. At lower doses, however, the same cell types may stimulate CTL responses without exogenous GSH, and the responses may be even inhibited in these cases by GSH. CTL responses were not suppressed by high numbers of professional APC, and GSH had no substantial effect on CTL responses after in vivo immunization with professional APC or a cysteine-releasing tumor variant. However, exogenous GSH reconstituted the otherwise weak CTL response in vitro against splenic adherent cells from athymic (nude) mice. Experiments with cloned T cells (D10.G4.1) finally showed that stimulation with graded concentrations of mitogen causes a dose-dependent decrease of intracellular GSH levels. These effects are expected to play a role in "high zone tolerance," in CTL responses against certain types of tumors, and in pathological conditions with a GSH deficiency.
Oxidative conditions potentiate the activation of the nuclear transcription factor kappa B (NF kappa B) and the activator protein-1 (AP-1) in intact cells, but inhibit their DNA binding activity in vitro. We now show that both the activation of NF kappa B and the inhibition of its DNA binding activity is modulated in intact cells by the physiological oxidant glutathione disulphide (GSSG). NF kappa B activation in human T lineage cells (Molt-4) by 12-O-tetradecanoyl-phorbol 13-acetate was inhibited by dithiothreitol, and this was partly reversed by the glutathione reductase inhibitor 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) or by hydrogen peroxide, indicating that GSSG may be required for NF kappa B activation. These effects of BCNU and hydrogen peroxide were not seen in glutathione-depleted cells. However, NF kappa B and AP-1 activation were potentiated by dithiothreitol if added to cell cultures 1 h after the phorbol ester, indicating that a shift of redox conditions may support optimal oxidative activation with minimal inhibition of DNA binding. The elevation of intracellular GSSG levels by BCNU before stimulation suppressed the chloramphenicol acetyltransferase expression dependent on NF kappa B but increased that dependent on AP-1. This selective suppression of NF kappa B was also demonstrable by electrophoretic mobility shift assays. In vitro, GSSG inhibited the DNA binding activity of NF kappa B more effectively than that of AP-1, while AP-1 was inhibited more effectively by oxidized thioredoxin.
To establish whether the low cysteine and glutathione levels in HIV-infected patients and SIV-infected rhesus macaques may be consequences of an abnormal cysteine catabolism, we analyzed sulfate and glutathione levels in macaques. Muscle tissue (m. vastus lateralis and m. gastrocnemius) of SIV-infected macaques (n = 25) had higher sulfate and lower glutathione and glutamate levels than that of uninfected controls (n =9). Hepatic tissue, in contrast, showed decreased sulfate and glutathione disulfide (GSSG) levels, and increased gamma-glutamylcysteine synthetase (gamma-GCS) activity. These findings suggest drainage of the cysteine pool by increased cysteine catabolism in skeletal muscle tissue, and by increased hepatic glutathione biosynthesis. Cachectic macaques also showed increased urea levels and decreased glutamine/urea ratios in the liver, which are obviously related to the abnormal urea excretion and negative nitrogen balance commonly observed in cachexia. As urea production and net glutamine synthesis in the liver are strongly influenced by proton-generating processes, the abnormal hepatic urea production may be the direct consequence of the cysteine deficiency and the decreased catabolic conversion of cysteine into sulfate and protons in the liver.
Glutathione (GSH), a cysteine-containing tripeptide, is essential for the viability and function of virtually all cells. In vitro studies showing that low GSH levels both promote HIV expression and impair T cell function suggested a link between GSH depletion and HIV disease progression. Clinical studies presented here directly demonstrate that low GSH levels predict poor survival in otherwise indistinguishable HIV-infected subjects. Specifically, we show that GSH deficiency in CD4 T cells from such subjects is associated with markedly decreased survival 2-3 years after baseline data collection (Kaplan-Meier and logistic regression analyses, P < 0.0001 for both analyses). This finding, supported by evidence demonstrating that oral administration of the GSH prodrug N-acetylcysteine replenishes GSH in these subjects and suggesting that N-acetylcysteine administration can improve their survival, establishes GSH deficiency as a key determinant of survival in HIV disease. Further, it argues strongly that the unnecessary or excessive use of acetaminophen, alcohol, or other drugs known to deplete GSH should be avoided by HIV-infected individuals.
The combination of abnormally low plasma cystine and glutamine levels, low natural killer (NK) cell activity, skeletal muscle wasting or muscle fatigue, and increased rates of urea production defines a complex of abnormalities that is tentatively called "low CG syndrome." These symptoms are found in patients with HIV infection, cancer, major injuries, sepsis, Crohn's disease, ulcerative colitis, chronic fatigue syndrome, and to some extent in overtrained athletes. The coincidence of these symptoms in diseases of different etiological origin suggests a causal relationship. The low NK cell activity in most cases is not life-threatening, but may be disastrous in HIV infection because it may compromise the initially stable balance between the immune system and virus, and trigger disease progression. This hypothesis is supported by the coincidence observed between the decrease of CD4+ T cells and a decrease in the plasma cystine level. In addition, recent studies revealed important clues about the role of cysteine and glutathione in the development of skeletal muscle wasting. Evidence suggests that 1) the cystine level is regulated primarily by the normal postabsorptive skeletal muscle protein catabolism, 2) the cystine level itself is a physiological regulator of nitrogen balance and body cell mass, 3) the cyst(e)ine-mediated regulatory circuit is compromised in various catabolic conditions, including old age, and 4) cysteine supplementation may be a useful therapy if combined with disease-specific treatments such as antiviral therapy in HIV infection.