Article

Activation of murine macrophages by G1-4A, a polysaccharide from Tinospora cordifolia , in TLR4/MyD88 dependent manner

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Abstract

Macrophages are centrally placed in the innate immune system and their activation is crucial to the generation of appropriate immune response in the event of any pathogenic invasion, tumorigenesis or other human diseases. Many plant derived polysaccharides are known to activate macrophages. In the present study, effects of G1-4A, a polysaccharide derived from Tinospora cordifolia, on the activation of macrophages were investigated. Our data demonstrated the up regulation of expression of TNF-α, IL-β, IL-6, IL-12, IL-10 and IFN-γ in RAW 264.7 cell line and peritoneal macrophages after G-14A treatment. Nitric oxide levels were also enhanced along with up-regulation of NOS2 expression in murine macrophages post G1-4A treatment. Further, G1-4A treatment up-regulated the surface expression of MHC-II and CD-86 in macrophages. Using siRNA against TLR4, MyD88 and anti-TLR4 blocking antibodies, we established that G1-4A activated macrophages by classical pathway in TLR4-MyD88 dependent manner. Additionally, G1-4A treatment activated p38, ERK and JNK MAPKs in macrophages. Using pharmaceutical inhibitors of above MAPKs we concluded that G1-4A activates the macrophages by activation of p38, ERK and JNK MAPKs in RAW264.7 macrophages. Thus our data suggests the activation of macrophages by classical pathway after treatment of G1-4A.

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... G1-4A a polysaccharide of Tinospora cordifolia effectively activated macrophages via TLR4-MyD88 dependent pathway and plays an important role in innate immunity (Gupta et al., 2017). ...
... One of the studies depicted that silver nano-particles of Piper longum fruit extract has potential antibacterial activity and cytotoxicity activity against MCF-7 (breast cancer cell lines) cell lines (Reddy, Vali, Rani, & Rani, 2014) while Tinospora cordifolia has promising antiviral, immunomodulatory, and thrombolytic properties (Alrumaihi et al., 2019;Gupta et al., 2017;Mary et al., 2003;Velazquez et al., 2009). ...
... Ocimum tenuiflorum can affect the neutrophil and lymphocyte population (Mukherjee et al., 2005), whereas Psoralea corylifolia induced the NK-cell activity and antibodies-dependent cytotoxicity in cancer cells (Latha et al., 2000). Tinospora cordifolia activated the innate immune response via TLR4-MY88 axis (Gupta et al., 2017) and ameliorated cyclophosphamide-induced immunosuppression in rats (Alrumaihi et al., 2019). Viscum album regulated immune indices in radioactive exposed children (Chernyshov et al., 2000) while Withania somnifera has a beneficial role in humoral immunity (Davis & Kuttan, 2000). ...
Article
Traditional Indian medical practices (Ayurveda, Siddha, Unani, and homeopathy) are a vast reservoir of knowledge about medicinal plants. The promising pharmacological properties of these plants have paved the way for developing therapy against novel Coronavirus (CoV) infection. The current review will summarize published works of literature on the effects of traditional Indian medicinal plants against acute respiratory infection (COVID‐19, SARS, Influenza, and Respiratory syncytial virus infection) and registered clinical trials of traditional Indian herbal medicines in COVID‐19. The current study aims to comprehensively evaluate the data of traditional Indian medicinal plants to warrant their use in COVID‐19 management. PubMed, Embase, and Cochrane databases were searched along with different clinical trial databases. A total of 22 relevant traditional Indian medicinal plants (35 relevant studies) were included in the current study having potential antiviral properties against virus‐induced respiratory illness along with promising immunomodulatory and thrombolytic properties. Further, 36 randomized and nonrandomized registered clinical trials were also included that were aimed at evaluating the efficacy of herbal plants or their formulations in COVID‐19 management. The antiviral, immunomodulatory, and thrombolytic activities of the traditional Indian medicinal plants laid down a strong rationale for their use in developing therapies against SARS‐CoV‐2 infection. The study identified some important potential traditional Indian medicinal herbs such as Ocimum tenuiflorum, Tinospora cordifolia, Achyranthes bidentata, Cinnamomum cassia, Cydonia oblonga, Embelin ribes, Justicia adhatoda, Momordica charantia, Withania somnifera, Zingiber officinale, Camphor, and Kabusura kudineer, which could be used in therapeutic strategies against SARS‐CoV‐2 infection.
... Purified polysaccharide G1-4A, isolated from the T. cordifolia has exhibited B-Cell mitogenic activity and protected BALB/c mice from LPS induced endotoxic shock in earlier studies [28]. Previously, we have reported the intracellular clearance of MTB by G1-4A treatment through the modulation of host responses such as activation of macrophages in TLR4-MyD88 dependent manner [21,29]. G1-4A is an arabinogalactan polysaccharide which is isolated from polysaccharide rich aqueous extract of the stem of T. cordifolia following gel chromatography. ...
... Pathogenassociated molecular patterns (PAMPs) mediated activation of infected macrophages is known to overcome the immune perturbation caused by MTB and results into phagosome lysosome fusion, cytokine secretion and production of reactive oxygen and nitrogen intermediates (ROI and RNI) leading to impaired replication of MTB inside macrophages [33]. In earlier study from our lab we reported that G1-4A, a plant based polysaccharide inhibits the survival of MTB in macrophages through classical activation in TLR4-MyD88 dependent manner and in BALB/c mice through the induction of Th1 immune response [21,29]. ...
... PRE treatment up regulated the expression of MHC-II and CD-86 in macrophages either infected or uninfected, which suggests that PRE treatment enhances the Ag processing and presentation ability of infected macrophages. Nitric oxide production by macrophages in response to an exogenous signal is a hallmark of classically activated macrophages (M1 phenotype) which contributes significantly in the antimicrobial response of these cells [29,36]. We observed enhanced expression of NOS2 protein after PRE treatment with subsequent rise in NO levels in supernatants of macrophages. ...
... The results indicated significant up-regulation of these cytokine genes in PBMCs isolated from supplemented birds, compared with the control. These results are in accordance with the study where polysaccharide (G1-4A arabinogalactan polysaccharide) derived from T. cordifolia was found to stimulate murine macrophages leading to up-regulation of IL-2, IFN-γ, IL-4, and IL-1β in vitro [40]. Therefore, these results are indicative of the immunomodulatory potential of this herb in chickens, through alteration of the expressions of immune response cytokines. ...
... It has been found that G1-4A, an arabinogalactan polysaccharide from the stem of T. cordifolia, responsible for its immunomodulatory potential, acts by activating the B cells polyclonally, via an increase in CD69 expression in lymphocytes. TLR4 on B lymphocytes and macrophages acts as a receptor for G1-4A polysaccharide, activating these immune cells via TLR4/MyD88 dependent manner [40,43]. Similarly, G1-4A leads to enhanced antigen presentation from dendritic cells, and further activation of cytotoxic T cells [44]. ...
Article
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Infectious bursal disease (IBD), caused by infectious bursal disease virus (IBDV), is characterized by severe immunosuppression in young chicks of 3 to 6 week age group. Although vaccines are available to prevent IBD, outbreaks of disease are still noticed in the field among vaccinated flocks. Further, the birds surviving IBD become susceptible to secondary infections caused by various viral and bacterial agents. This study assessed the immunoprophylactic potential of Cytosine-guanosinedeoxynucleotide (CpG) oligodeoxynucleotides (ODN) and Tinospora cordifolia stem aqueous extract in the specific pathogen free (SPF) chicks, experimentally infected with very virulent IBDV (vvIBDV). Both of these agents (CpG ODN and herbal extract) showed significant increase in the IFN-γ, IL-2, IL-4, and IL-1 levels in the peripheral blood mononuclear cells (PBMCs) (p < 0.05) of chickens in the treatment groups following IBD infection.Further we found significant reduction in mortality rate in vvIBDV infected chicks treated with either, or in combination, compared with the birds of control group. Additionally, the adjuvant or immune enhancing potential of these two immunomodulatory agents with the commercially available IBDV vaccine was determined in chicks. The augmentation of vaccine response in terms of an enhanced antibody titer after vaccination, along with either or a combination of the two agents was noticed. The findings provide a way forward to counter the menace of IBDV in the poultry sector through use of these herbal or synthetic immunomodulatory supplements.
... It established that G1-4A as a TLR4 agonist is having the potential to cause M1-activation of macrophages like Interferon gamma (IFN-γ) and lipopolysaccharide (LPS). 28 In the human subject also, it is considered as an immune stimulator by increasing the killing capacities of neutrophils and phagocytosis activities. 29 Different extracts of Tinospora cordifolia also exhibit immunemodulatory activity by splenocyte proliferation. ...
... Hematological and serum chemistry parameters were within the normal limits and there were no treatment related gross or histopathological findings14,15,16 Some pilot studies conducted on efficacy and safety evaluation ofAshwagandha showed normal hepatic functions and renal functions when given for 7 weeks.17 A study on healthy volunteers (12 Male &6Female, age: 18-30 years, and BMI:[19][20][21][22][23][24][25][26][27][28][29][30] had shown normal organ function tests before and after the intervention. After baseline investigations, they received WS capsules (Rx) (aqueous extract, 8:1) daily in two divided doses with increase in daily dosage every 10 days for 30 days (750 mg/day ×10 days, 1000 mg/day × 10 days, 1250 mg/day × 10 days). ...
Book
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This booklet covers easily available medicinal plant products that have been used in Ayurvedic system of medicine for various indications and have useful properties in respiratory infections and have been also shown to have antiviral, anti-inflammatory, immunomodulatory ands other properties which can be beneficial in such infections.
... Specifically, the activated TLR4 can promote the phosphorylation of interleukin-1 receptor-related kinase (IRAK-1) to activate TRAF6 (61). Further, the MAKPs family (including JNK, ERK, and p38) is activated to produce phosphorylation and promote the secretion of downstream related immune cytokines (62). In this study, SLNP could promote TLR4 expression, upregulated the mRNA expression of TRAF6, IRF3, JNK, ERK and p38, the protein expression of TRAF6, IRF3, p-JNK, p-ERK, and p-p38, which was proved by the study of JCH-1, a purified polysaccharide isolated from Isaria cicadae Miquel. ...
Article
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Background Sparassis latifolia ( S. latifolia ) is a precious edible fungus with multiple biological activities. To date, no study has been investigated the underlying molecular mechanism of immunoregulation caused by the neutral polysaccharide of S. latifolia. Materials and methods To investigate immunomodulatory mechanism of S. latifolia neutral polysaccharide (SLNP), SLNP was obtained from S. latifolia and its structure, immune receptors and regulation mechanism were studied. Results S. latifolia neutral polysaccharide consisted of arabinose, galactose, glucose, xylose, and mannose with a molar ratio of 6:12:63:10:5. SLNP was a pyran polysaccharide with a relative molecular weight of 3.2 × 10 ⁵ Da. SLNP promoted the proliferation of RAW264.7, which further induced the secretions of nitric oxide, TNF-α, IL-6, and IFN-β, and upregulated the immune receptor TLR4 expression. Moreover, SLNP increased remarkably the levels of TRAF6, IRF3, JNK, ERK, p38, and p38 mRNA and protein mediated by TLR4. Conclusion S. latifolia neutral polysaccharide regulated the immune function of RAW264.7 through MyD88-dependent and -independent signaling pathways mediated by TLR4 receptor, which suggests that SLNP is a new immunomodulator.
... Elevated expression levels of IFNs and MCP-1 were detected, but the levels of IFNs were much lower than that of IL-1β ( Figure 2). Our result was in agreement with other ndings that IFNs were less abundantly produced by the stimulated macrophages, compared to IL-1β or TNF-α [44][45][46]. However, the degree of increasing in the expression level of IFNs was obviously higher than that of IL-1β in PM patients [47][48][49]. ...
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Backgrounds: This study was designed to investigate the role of the nucleotide-binding-domain (NBD)-and leucine-rich repeat (LRR)-containing (NLR) family, pyrin-domain-containing 3 (NLRP3) inflammasome in the pathogenesis of polymyositis (PM). Results: We found that the percentage of CD68+ cells, and the expression levels of NLRP3, caspase-1 and interleukin-1 beta (IL-1β) in the muscle tissue were elevated in 27 PM patients. LPS/ATP treatment in the Raw 264.7 macrophages resulted in activation of NLRP3 inflammasome and secretion of IL-1β as well as interferons (IFNs) and monocyte chemotactic protein-1 (MCP-1). Meanwhile, LPS/ATP challenged activation of NLRP3 inflammasome induced overexpression of major histocompatibility complex class I (MHC-I), a key molecular to develop to PM, in the co-cultured C2C12 cells. Genetic knockdown of NLRP3 inflammasome using siRNA or pharmacological inhibition of NLRP3 inflammasome using MCC950 effectively suppressed MHC-I overexpression in the co-cultured C2C12 cells. Certain levels of IL-1β rather than IFNs showed the effect of up-regulating MHC-I expression in C2C12 cells. IL-1β blockade using neutralizing IL-1β monoclonal antibody or siRNA of IL-1β suppressed MHC-I overexpression. In vivo, NLRP3 inflammasome inhibition using MCC950 reduced the expression of NLRP3, IL-1β and MHC-I in the muscle tissue of PM modal rats. Also, it attenuated the intensity of muscle inflammation as well as the CRP, CK, and LDH levels in the serum. Conclusions: Collectively, these results suggested that NLRP3/caspase-1/IL-1β axis may play an important role in the development of PM. Inhibition of NLRP3 activation may hold promise in the treatment of PM.
... Similarly, the effect of G1-4A on macrophage RAW264.7 is related to TLR4. An experiment showed that macrophage activity could be decreased after blocking TLR4 activity using siRNA and antibodies, which suggests that G1-4A activates macrophages via a TLR4-MyD88dependent pathway (22,68). ...
Article
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Polysaccharides are among the most important members of the biopolymer family. They are natural macromolecules composed of monosaccharides. To date, more than 300 kinds of natural polysaccharide compounds have been identified. They are present in plants, animals, and microorganisms, and they engage in a variety of physiological functions. In the 1950s, due to the discovery of their immunoregulatory and anti-tumor activities, polysaccharides became a popular topic of research in pharmacology, especially in immunopharmacology. Plants are an important source of natural polysaccharides. Pharmacological and clinical studies have shown that plant polysaccharides have many functions, such as immune regulation, anti-tumor activity, anti-inflammatory activity, anti-viral functions, anti-radiation functions, and a hypoglycaemic effect. The immunomodulatory effects of plant polysaccharides have received much attention. Polysaccharides with these effects are also referred to as biological response modifiers (BRMs), and research on them is one of the most active areas of polysaccharide research. Thus, we summarize immunomodulatory effects of botanical polysaccharides isolated from different species of plants on the macrophage. The primary effect of botanical polysaccharides is to enhance and/or activate macrophage immune responses, including increasing reactive oxygen species (ROS) production, and enhancing secretion of cytokines and chemokines. Therefore, it is believed that botanical polysaccharides have significant therapeutic potential, and represent a new method for discovery and development of novel immunomodulatory medicine.
... Receptors on surface of macrophages, e.g. Toll-like receptors (TLRs) and complement receptor type 3 (CR3), may interact with polysaccharides [17], stimulating macrophages to release nitric oxide (NO) and cytokines to kill pathogens [18]. Consequently, exogenous antioxidants and phagocytosis ability of macrophages may have vital roles in anti-viral defenses. ...
Article
Rhizome of the fern Dryopteris crassirhizoma Nakai is used as an antiviral drug in China. The objectivewas to characterize physicochemical properties, structural features and antioxidant and immunological activities of D. crassirhizoma polysaccharides. An acidic polysaccharide fraction (DCP-3) was obtained from Dryopteris crassirhizoma Nakai by purification with DEAE-52 and Sephadex G-100. DCP-3was a novel triple-helical polysaccharide with an average MW of 273.2 kDa. This fraction was mainly composed of galactose (36.65%), xylose (34.75%), arabinose (17.07%) and mannose (9.22%). DCP-3 had strong activity for scavenging DPPH radical (IC50: 2.04 mg/mL), hydroxyl radical (IC50: 1.70 mg/mL), and superoxide anions (IC50: 4.20 mg/mL) and also was capable of reducing ferric ions. In addition, nitric oxide productionwas enhanced in RAW264.7 macrophages stimulated by DCP-3. Based on these bioactivities, we inferred that DCP-3 was a functional component of D. crassirhizoma and may confer antivirus activity, with potential applications in functional food and drug industries.
... At the cellular level, many polysaccharides can activate macrophages to increase immune molecules, including nitric oxide (NO) and other proinflammatory cytokines. [89][90][91] At the genetic level, some polysaccharides are able to increase messenger RNA (mRNA) expression of inducible nitric oxide synthase (iNOS) and other cytokines. 31,92,93 At the protein level, the use of western blot analysis reveals that several natural polysaccharides can induce the activation of signal proteins, such as p38, extracellular signal-regulated kinase (ERK), JNK, p65 and p50. ...
Article
In recent years, natural polysaccharides have received increasing attention and become one kind of popular dietary nutrients owing to their various biological functions. Similarly, intestinal microbiota is a hot topic because it is closely associated with human health. Firstly, the summary of microbiota includes methods to study intestinal microorganisms, the changes in microbial composition and main factors to affect gut microbiota composition. Besides, the summary of the immune system contains information on T cells, macrophages, innate lymphoid cells and pattern recognition receptors. Meanwhile, the summary of polysaccharides mainly introduces source, extraction and purification methods, and structural determination of polysaccharides. Gut microbiota can affect the immune system through its composition, structural components and metabolites, while immune deficiency gives rise to dysbiosis of intestinal microbes. Natural polysaccharides not only enhance immunity, but also suppress excessive immune responses caused by various stimuli through directly regulating immune cells or/and improving microbial composition. Notably, natural polysaccharides exhibit potential applications in functional foods due to their abilities to suppress inflammation and cancer. Therefore, we present a comprehensive overview on the gut microbiota, immunity and polysaccharides in many aspects.
... Among them, IL-6 level had no difference between each surface, while IL-10 level in Ti-SLA, Ti-NW and Ti-NW-Zn groups were significantly higher than those in the cp-Ti group. IL-6 is recognized to be involved in pro-inflammation regulation, and IL-10 is the anti-inflammatory cytokine associated with the polarization of M2 macrophages and wound healing [46]. These results suggested that the preferences of macrophages in all four surfaces were tended to be the M2 phenotype rather than M1 phenotype, and Ti-SLA, Ti-NW and Ti-NW-Zn surfaces were more preferred to induce the M2 phenotype than the cp-Ti surface. ...
Article
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Titanium (Ti) and its alloys as bio-implants have excellent biocompatibilities and osteogenic properties after modification of chemical composition and topography via various methods. The corrosion resistance of these modified materials is of great importance for changing oral system, while few researches have reported this point. Recently, oxidative corrosion induced by cellular metabolites has been well concerned. In this study, we explored the corrosion behaviors of four common materials (commercially pure Ti, cp-Ti; Sandblasting and acid etching-modified Ti, Ti-SLA; nanowires-modified Ti, Ti-NW; and zinc-containing nanowires-modified Ti, Ti-NW-Zn) with excellent biocompatibilities and osteogenic capacities under the macrophages induced-oxidizing microenvironment. The results showed that the materials immersed into a high oxidizing environment were more vulnerable to corrode. Meanwhile, different surfaces also showed various corrosion susceptibilities under oxidizing condition. Samples embed with zinc element exhibited more excellent corrosion resistance compared with other three surfaces exposure to excessive H2O2. Besides, we found that zinc-decorated Ti surfaces inhibited the adhesion and proliferation of macrophages on its surface and induced the M2 states of macrophages to better healing and tissue reconstruction. Most importantly, zinc-decorated Ti surfaces markedly increased the expressions of antioxidant enzyme relative genes in macrophages. It improved the oxidation microenvironment around the materials and further protected their properties. In summary, our results demonstrated that Ti-NW-Zn surfaces not only provided excellent corrosion resistance properties, but also inhibited the adhesion of macrophages. These aspects were necessary for maintaining osseointegration capacity and enhancing the corrosion resistance of Ti in numerous medical applications, particularly in dentistry.
... The extract was found more active towards KB and SiHa cell lines than pure molecules, which showed specific activity. In addition, a study by Gupta, Rajan and Kulkarni [117] revealed that treatment of G1-4A activates murine macrophages through the classical pathway in TLR4 dependent manner. It also promotes the expression of pro-inflammatory cytokines such as TNF-α, IL-1β, IFN-γ, IL-12 and IL-6 in RAW 264.7 cells. ...
Article
Tinospora cordifolia (Giloy) is a medicinal plant used in folk and Ayurvedic medicines throughout India since ancient time. All the parts of the plant are immensely useful due to the presence of different compounds of pharmaceutical importance belonging to various groups as alkaloids, diterpenoid lactones, glycosides, steroids, sesquiterpenoid, and phenolics. These compounds possess pharmacological properties which makes it anti-diabetic, antipyretic, anti-inflammatory, anti-oxidant, hepatoprotective, and immuno-modulatory. However, due to the increasing population, there is an inadequate supply of drugs. Therefore, this review focuses on the phytochemistry, ethnopharmacology, clinical application and its conservation strategies so that the plant can be conserved for future generations and utilized as an alternative medicine as well as to design various pharmacologically important drugs.
... Thus, the acidic arabinogalactan were capable of modulating both innate and adaptive immune responses. Gupta, Rajan & Kulkarni [67] reported up regulation of expression of TNF-α, IL-β, IL-6, IL-12, IL-10 and IFN-γ in RAW 264.7 cell line and peritoneal macrophages after treatment with the same acidic arabinogalactan. Nitric oxide levels were also enhanced along with up-regulation of NOS2 expression in murine macrophages due to treatment of G1-4A. ...
Article
The emergence of the novel coronavirus, SARS-CoV-2 has pushed forward the world to experience the first pandemic of this century. Any specific drug against this RNA virus is yet to be discovered and presently, the COVID-19 infected patients are being treated symptomatically. During the last few decades, a number of polysaccharides with potential biological activities have been invented from Indian medicinal plants. Many polysaccharides, such as sulfated xylomannan, xylan, pectins, fucoidans, glucans, glucoarabinan, and arabinoxylan from Indian medicinal plants, have been shown to exhibit antiviral and immunomodulating activities. Plant polysaccharides exhibit antiviral activities through interference with the viral life cycle and inhibition of attachment of virus to host cell. Intake of certain immune stimulating plant polysaccharides may also protect from the virus to a certain extent. In process of continuous search for most potent drug, Indian plant polysaccharides may emerge as significant biomaterial to combat COVID-19. This review explores a number of polysaccharides from Indian medicinal plants which showed antiviral and immunomodulating activities. It is aimed to provide an overview about the composition, molecular mass, branching configuration and related bioactivities of polysaccharides which is crucial for their classification as possible drug to induce immune response in viral diseases.
... 16 When they are activated, macrophages can increase the secretion of the immune molecules, including Nitric Oxide (NO) and other pro-inflammatory cytokines, such as Tumour Necrosis Factor-α (TNF-α), interleukin (IL)-1, IL-6, IL-8, IL-12 and Interferon (IFN)-γ. [17][18][19] Especially, NF-κB is recognized as a key regulator of cytokine expression and is closely associated with the generation of ROS and induction of apoptosis in macrophages. 20 Besides secretion the immune molecules, macrophages can exert their immunoregulation effects by devouring foreign pathogens and cell fragments. ...
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PCp-I is a polysaccharide isolated and identified from the Psoralea corylifolia L. by our research group. In this study, the immunomodulatory effects of PCp-I on RAW264.7 cells was evaluated. PCp-I could enhance the level of NO along with up-regulation of iNOS mRNA in RAW264.7 cells. The PCp-I could significantly up-regulate the mRNA expression of TNF- α and IL-6 in RAW264.7 cells, and then the expression of TNF- α, IL-6, ROS and the phagocytic activity were increased. Additionally, PCp-I could significantly up-regulate the phosphorylation level of p65, p38, ERK and JNK proteins, which proved that PCp-I could activate the macrophages by MAPKs and NF- κB signalling pathway and the TLR4 may be one of the receptors of PCp-I regulate the RAW264.7 cells.
... The anti-inflammatory properties of Tinospora cordifolia extract (TCE) is mediated via suppression of proinflammatory cytokines such as IL-1β, IL-6, IL-17 and TNF-α in LPS induced Raw 264.7 macrophages, neuroinflammatory rat model and in arthritis model [87][88][89]. The polysaccharide G1-4A from Tinospora cordifolia shows anti-microbial activity by inhibiting the survival of both drug sensitive as well as multiple drug resistant Mycobacterium tuberculosis (MTB) strains under both in vitro and in vivo conditions through the modulation of the host immune system in a TLR4-dependent manner [89,90]. Thus, these studies suggest that Tinospora cordifolia exhibits anti-viral and anti-inflammatory properties. ...
Article
In 2020, a novel strain of coronavirus (COVID-19) has led to a significant morbidity and mortality worldwide. As of the date of this writing, a total of 116 M cases has been diagnosed worldwide leading to 2.5 M deaths. The number of mortalities is directly correlated with the rise of innate immune cells (especially macrophages) in the lungs that secrete inflammatory cytokines (IL-1β and IL-6) leading to the development of "Cytokine Storm Syndrome" (CSS), multi-organ-failure and death. Given that currently the treatment of this condition is rare and release of effective vaccine might be months away, here, we review the plants and their pharmacologically active-compounds as potential phytopharmaceuticals for the virus induced inflammatory response. Experimental validation of the effectiveness of these natural compounds to prevent or reduce the cytokine storm might be beneficial as an adjunct treatment of SARS-CoV-2.
... demonstrated that polysaccharides derived from Tinospora cordifolia induce the secretion of pro-inflammatory cytokines, such as TNF-α, IL-1β, IL-6, IL-12, and IFN-γ, by RAW 264.7. Moreover, NO levels are also enhanced along with the up-regulation of iNOS and surface MHC-II and CD-86 expression in murine Mfs post-treatment with T. cordifolia polysaccharides (Gupta et al., 2017). as basal antibody background reference. ...
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Marine seaweeds are a rich source of sulfated polysaccharides (SPs) with several biological activities, including antitumor effect. Some polysaccharides are also described to activate macrophages (MΦs) to an antitumor M1-like phenotype. Here, we evaluated the capacity of SPs extracts obtained from three seaweed species, Gracilaria cornea (Gc-E), Gracilaria birdiae (Gb-E), and Solieria filiformis (Sf-E), to activate the MΦs antitumor M1 phenotype. The nitric oxide production, MHCII, and CD86 M1 markers were evaluated to screening the bioactive SPs profile on murine MΦs (RAW 264.7 cells). The direct SPs antiproliferative effect was tested on melanoma B16-F10 cells. In another experimental setting, B16-F10 cells were incubated with a conditioned medium obtained from MΦs exposed to SPs. The three SPs tested induced NO release. Sf-E directly inhibited B16-F10 cells proliferation compared with the saline group, but Gc-E and Gb-E failed to inhibit cell proliferation. Notably, a conditioned medium (CM) of MΦs incubated with Gc-E and Sf-E, but not of Gb-E, inhibited the proliferation of B16-F10 cells. Gc-E also induced TNF-α release and increase of M1 markers such as iNOS, MHCII, and CD86. Therefore, Gc-E activates a macrophage M1 phenotype, which in turn releases a factor that inhibits B16-F10 proliferation.
... Thus, the mechanism of action occurs through the binding of polysaccharides to groups of transmembrane type I proteins, known as Toll-like receptors (TLRs). These receptors stimulate signaling pathways in order to activate macrophages [63]. Therefore, macrophages act by damaging pathogens by phagocytosis, triggering the release of antigens responsible for immunological responses [64]. ...
Article
There is a current tendency towards bioactive natural products that can be used in different areas such as food, pharmaceutical, and biomedical. In the last decades, the polysaccharides have attracted an increasing interest because of the potent nontoxic effects, therapeutic properties, and the diversified range of applications. Polysaccharides are complex and heterogeneous macromolecules, constituted of different monosaccharides, and in some cases of glucuronic acid and sulphate groups. Polysaccharides with biological activity can be derived from plants, animals and microorganisms, especially microalgae. Microalgae are considered one of most promising source of these compounds that have already proved to have several important biological properties. In this sense, our objective is to elucidate the use of bioactive polysaccharides from microalgae in biomedical applications, emphasizing the biological activity of these compounds. Furthermore, the microalgal biomass production systems and polysaccharides extraction methods were presented and discussed.
... Elevated expression levels of IFNs and MCP-1 were detected, but the levels of IFNs were much lower than that of IL-1β (Fig. 2). Our result was in agreement with other findings that IFNs were less abundantly produced by the stimulated macrophages, compared to IL-1β or TNF-α [44][45][46]. However, the degree of increasing in the expression level of IFNs was obviously higher than that of IL-1β in PM patients [47][48][49]. ...
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Objective This study was designed to investigate the role of the nucleotide-binding-domain -and leucine-rich repeat -containing (NLR) family, pyrin-domain-containing 3 (NLRP3) inflammasome in the pathogenesis of polymyositis (PM). Methods Immunochemistry was performed to analyze the NLRP3, caspase-1 and interleukin-1 beta (IL-1β) expression in the muscle tissue of PM patients. Rat model of PM and C2C12 cell were used to investigate the potential role of NLRP3 inflammasome in PM. Results The percentage of CD 68+ macrophages, and the expression levels of NLRP3, caspase-1 and IL-1β in the muscle tissue were elevated in 27 PM patients. LPS/ATP treatment resulted in activation of NLRP3 inflammasome and secretion of IL-1β as well as interferons (IFNs) and monocyte chemotactic protein-1 (MCP-1) in the Raw 264.7 macrophages. Meanwhile, LPS/ATP challenged activation of NLRP3 inflammasome induced overexpression of major histocompatibility complex class I (MHC-I), a key molecular of PM in the co-cultured C2C12 cells. The effect was decreased by treatment of NLRP3 inflammasome inhibitor MCC950 or siRNA of NLRP3 inflammasome. These findings suggested certain levels of IL-1β rather than IFNs up-regulated MHC-I expression in C2C12 cells. IL-1β blockade using neutralizing IL-1β monoclonal antibody or siRNA of IL-1β suppressed MHC-I overexpression. In vivo, NLRP3 inflammasome inhibition by MCC950 reduced the expression of NLRP3, IL-1β and MHC-I in the muscle tissue of PM modal rats. Also, it attenuated the intensity of muscle inflammation as well as the CRP, CK, and LDH levels in the serum. Conclusion NLRP3/caspase-1/IL-1β axis may play an important role in the development of PM. Inhibition of NLRP3 activation may hold promise in the treatment of PM.
... Macrophages have gained great interest within the previous decade and currently their role in the stimulation of innate immunity to potentially prevent IDs is getting appreciated (Gupta et al., 2017). Macrophages or mononuclear phagocytes are majorly found in connective tissues and every organ in the body and these cells are also well known as professional phagocytes in which they express a multitude of receptors on their surfaces (Mitchell and Isberg, 2017;Murray and Wynn, 2012). ...
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Macrophages play a vital role in primary immune responses mainly by carrying out phagocytosis that involves the production of nitric oxide (NO). NO is synthesized by inducible nitric oxide synthase (iNOS) to combat aetiological agents that are able to cause infectious diseases (IDs). Asiatic acid (AA) and madecassoside (MA) are two pentacyclic triterpene compounds derived from Centella asiatica (Linn.) Urban that involved in many pharmacological activities of this plant. However, there is still limited study using a normal immune model that resembles a healthy community to test the immunomodulatory effect of these compounds. Thus, this study used unstimulated macrophages as an in vitro normal model to investigate the effect of both compounds on phagocytosis activity. To achieve the aim of this study, the effects of AA and MA, alone and in combination, on the phagocytosis uptake, NO production, and iNOS expression of macrophages after 24 hours of treatment were measured. Briefly, macrophages (J774A.1) were cultured in five groups, namely untreated macrophages, macrophages treated with lipopolysaccharides (LPS) as a positive control, and macrophages treated with AA and MA alone and in combination (AA + MA). The investigation on phagocytosis uptake, NO production, and iNOS expression were conducted by using microscopic analysis on Giemsastained slides, the Griess assay, and Western blot, respectively. The results presented that the combination (AA + MA) treatment enhanced phagocytosis uptake, NO production, and iNOS expression of macrophages when compared to the untreated macrophages as well as macrophages treated with AA and MA, respectively. In conclusion, the combination (AA + MA) treatment is able to stimulate phagocytosis activity of macrophages and this new finding provides initial knowledge for the development of a natural product-based preventive agent against IDs © 2021 Nurul Hikmah Harun et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
... In general, pectin-containing scaffolds are biocompatible [13][14][15][16][17][18]. However, nonspecific adsorption of blood proteins [19], including proteins of the complement system [20][21][22], and stimulation of macrophages to secrete pro-inflammatory cytokines and nitric oxide [23][24][25][26] has been reported with pectin materials. Non-specific protein adsorption, complement activation, and inflammation develop a foreign body response (FBR), which hinders the development of tissue engineering scaffolds due to the failure of integration of the implant with native tissue [27]. ...
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... A variety of Toll-like receptors (TLR) are expressed on the surface of macrophages [5]. TLR4 is an important TLR, which could be activated by a variety of PAMPs [6]. The high expression of TLR4 receptor on macrophages enables macrophages to quickly activate and plays a role in response to pathogen invasion [7]. ...
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Tuberculosis (TB), is one of the deadliest infectious‐diseases of human‐civilization. Approximately one‐third of global‐population is latently‐infected with the TB‐pathogen Mycobacterium tuberculosis (M.tb). The discovery of anti‐TB antibiotics leads to decline in death‐rate of TB. However, the evolution of antibiotic‐resistant, M.tb‐strain, and the resurgence of different immune compromised diseases re‐escalated the death‐rate of TB. WHO has already cautioned about the chances of pandemic‐situation in TB endemic countries unless the discovery of new antitubercular drugs, i.e., the need of the hour. Analysing the pathogenesis of TB it was found that M.tb evades the host by altering the balance of immune‐response and affects either by killing the cells or by creating inflammation. In the pre‐antibiotic era, traditional medicines were only therapeutic measures for different infectious‐diseases including tuberculosis. The ancient‐literatures of India or ample Indian traditional knowledge and ethnomedicinal‐practices are evidence for the treatment of TB using different indigenous plants. However, in the light of modern scientific approach, anti‐TB effects of those plants and their bioactive‐molecules were not established thoroughly. In this review, focus has been given on five bioactive‐molecules of different traditionally used Indian ethnomedicinal plants for treatment of TB or TB‐like symptom. These compounds are also validated with proper identification and their mode of action with modern scientific approaches. The effectiveness of these molecules for sensitive or drug‐resistant TB‐pathogen in clinical or preclinical studies were also evaluated. Thus, our specific aim is to highlight such scientifically validated bioactive compounds having anti‐mycobacterial and immuno‐modulatory activity for future use as medicine or adjunct‐therapeutic molecule for TB management.
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Ethnopharmacological relevance Tinospora cordifolia (Thunb.) Miers (Menispermaceae) is a Mediterranean herb, used in Ayurvedic, Siddha, Unani, and folk medicines. The herb is also used in conventional medicine to treat oxidative stress-related diseases and conditions, including inflammation, pain, diarrhea, asthma, respiratory infections, cancer, diabetes, and gastrointestinal disorders. Aim of the review The taxonomy, botanical classification, geographical distribution, and ethnobotanical uses of T. cordifolia, as well as the phytochemical compounds found in the herb, the toxicology of and pharmacological and clinical studies on the effects of T. cordifolia are all covered in this study. Materials and methods To gather information on T. cordifolia, we used a variety of scientific databases, including Scopus, Google Scholar, PubMed, Science Direct, and Springer Link. The information discussed focuses on biologically active compounds found in T. cordifolia, and common applications and pharmacological activity of the herb, as well as toxicological and clinical studies on its properties. Results The findings of this study reveal a connection between the use of T. cordifolia in conventional medicine and its antioxidant, anti-inflammatory, antihypertensive, antidiabetic, anticancer, immunomodulatory, and other biological effects. The entire plant, stem, leaves, root, and extracts of T. cordifolia have been shown to have a variety of biological activities, including antioxidant, antimicrobial, antiviral, antiparasitic, antidiabetic, anticancer, anti-inflammatory, analgesic and antipyretic, hepatoprotective, and cardioprotective impact. Toxicological testing demonstrated that this plant may have medicinal applications. T. cordifolia contains a variety of biologically active compounds from various chemical classes, including alkaloids, terpenoids, sitosterols, flavonoids, and phenolic acids. Based on the reports researched for this review, we believe that chemicals in T. cordifolia may activate Nrf2, which leads to the overexpression of antioxidant enzymes such as CAT, GPx, GST, and GR, and thereby induces the adaptive response to oxidative stress. T. cordifolia is also able to reduce NF-κB signalling by inhibiting PI3K/Akt, activating AMPK and sirtuins, and downregulating PI3K/Akt. Conclusions Our findings indicate that the pharmacological properties displayed by T. cordifolia back up its conventional uses. Antimicrobial, antiviral, antioxidant, anticancer, anti-inflammatory, antimutagenic, antidiabetic, nephroprotective, gastroprotective, hepatoprotective, and cardioprotective activities were all demonstrated in T. cordifolia stem extracts. To validate pharmacodynamic targets, further research is needed to evaluate the molecular mechanisms of the known compounds against gastrointestinal diseases, inflammatory processes, and microbial infections, as immunostimulants, and in chemotherapy. The T. cordifolia safety profile was confirmed in a toxicological analysis, which prompted pharmacokinetic assessment testing to confirm its bioavailability.
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The natural body’s defence system plays a critical role to keep away the person from infections and minimize the risk of falling sick regularly. The smart way to improve immunity is changing the lifestyle by consuming food that has immunomodulatory activity. Spices/herbs have been used as preservatives as well as traditional medicines since ancient times due to their disease prevention capability. Numerous preclinical and clinical trials over few spans revealed the benefits of spices/herbs and their bioactive compounds in the control and prevention of several complications such as arthritis, respiratory diseases, cancer, cardiovascular disease, glucose impairment, and brain disorders. This chapter deals with the active compounds of spices and herbs and their potential health benefits in the management of the immune system. Overall, extensive research is required to support claims on the immune-boosting effects of foods. KeywordsImmunomodulatorPhytochemicalsBiomoleculesImmunoregulatorAutoimmune diseasesDetoxification
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Chapter
Polysaccharides are present in plants, animals, and microorganisms, and they engage in a variety of physiological functions, including the immune function. The immunomodulatory effects of polysaccharides have received much attention. The primary impact of polysaccharides is to enhance and/or activate macrophage immune responses, including increasing the synthesis of cytokines. The polysaccharides have significant therapeutic potential as immunomodulatory agents.
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Macrophage activation by cytokines or microbial products such as LPS results in the induction and release of several key immune effector molecules including NO and IL-12. These have been shown to play crucial roles in the development of immunity to intracellular pathogens such as Leishmania. The molecular mechanisms underlying the induction of these effector molecules are not fully understood. We now show that the extracellular signal-related kinase (ERK) and p38 mitogen-activated protein (MAP) kinases play differential roles in the regulation of LPS-stimulated inducible NO synthase and IL-12 gene expression. In macrophages, LPS stimulates the simultaneous activation of all three classes of MAP kinases, ERK, c-jun N-terminal kinase, and p38, albeit with differential activation kinetics. However, studies using inhibitors selective for ERK (PD98059) and p38 (SB203580) show that while p38 plays an essential role in the induction of inducible NO synthase, ERK MAP kinases play only a minor role in promoting NO generation. In contrast, while p38 promotes induction of IL-12 (p40) mRNA, ERK activation suppresses LPS-mediated IL-12 transcription. The biological relevance of these regulatory signals is demonstrated by our finding that Leishmania lipophosphoglycans, which promote parasite survival, act by stimulating ERK MAP kinase to inhibit macrophage IL-12 production. Thus, as ERK and p38 MAP kinases differentially regulate the induction of the macrophage effector molecules, inducible NO synthase and IL-12, these kinases are potential targets not only for the development of novel strategies to combat intracellular pathogens but also for therapeutic immunomodulation.
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Macrophage activation determines the outcome of infection by Mycobacterium tuberculosis (Mtb). Interferon-γ (IFN-γ) activates macrophages by driving Janus tyrosine kinase (JAK)/signal transducer and activator of transcription–dependent induction of transcription and PKR-dependent suppression of translation. Microarray-based experiments reported here enlarge this picture. Exposure to IFN-γ and/or Mtb led to altered expression of 25% of the monitored genome in macrophages. The number of genes suppressed by IFN-γ exceeded the number of genes induced, and much of the suppression was transcriptional. Five times as many genes related to immunity and inflammation were induced than suppressed. Mtb mimicked or synergized with IFN-γ more than antagonized its actions. Phagocytosis of nonviable Mtb or polystyrene beads affected many genes, but the transcriptional signature of macrophages infected with viable Mtb was distinct. Studies involving macrophages deficient in inducible nitric oxide synthase and/or phagocyte oxidase revealed that these two antimicrobial enzymes help orchestrate the profound transcriptional remodeling that underlies macrophage activation.
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It has been shown recently that different genotypes of Mycobacterium tuberculosis induce distinct immune responses in the host, as reflected by variations in cytokine and iNOS expression. Because these molecules are probably regulated by multiple factors in vivo this complex phenomenon was partially analysed by assessing cytokine and iNOS expression by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) in an in vitro model of bone marrow-derived macrophages infected with three different M. tuberculosis genotypes: Canetti, H37 Rv and Beijing. Although the three genotypes induced production of iNOS and the different cytokines tested at 24 h post-infection, macrophages infected with the Beijing isolate expressed the highest levels of mRNA for iNOS, interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha, IL-12 cytokines and lower levels of IL-10 compared with cells infected with other genotypes. This expression pattern has been associated with infection control, but during infection in vivo with the Beijing genotype it is lost upon progression to chronic phase. The failure to control infection is likely to be influenced by cytokines produced by other cell types and bacterial molecules expressed during the course of disease. Results presented in this work show that each genotype has the ability to induce different levels of cytokine expression that could be related to its pathogenesis during infection.
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Botanical polysaccharides exhibit a number of beneficial therapeutic properties, and it is thought that the mechanisms involved in these effects are due to the modulation of innate immunity and, more specifically, macrophage function. In this review, we summarize our current state of understanding of the macrophage modulatory effects of botanical polysaccharides isolated from a wide array of different species of flora, including higher plants, mushrooms, lichens and algae. Overall, the primary effect of botanical polysaccharides is to enhance and/or activate macrophage immune responses, leading to immunomodulation, anti-tumor activity, wound-healing and other therapeutic effects. Furthermore, botanical and microbial polysaccharides bind to common surface receptors and induce similar immunomodulatory responses in macrophages, suggesting that evolutionarily conserved polysaccharide structural features are shared between these organisms. Thus, the evaluation of botanical polysaccharides provides a unique opportunity for the discovery of novel therapeutic agents and adjuvants that exhibit beneficial immunomodulatory properties.
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Comprehensive analysis of the gene expression profiles associated with human monocyte-to-macrophage differentiation and polarization toward M1 or M2 phenotypes led to the following main results: 1) M-CSF-driven monocyte-to-macrophage differentiation is associated with activation of cell cycle genes, substantiating the underestimated proliferation potential of monocytes. 2) M-CSF leads to expression of a substantial part of the M2 transcriptome, suggesting that under homeostatic conditions a default shift toward M2 occurs. 3) Modulation of genes involved in metabolic activities is a prominent feature of macrophage differentiation and polarization. 4) Lipid metabolism is a main category of modulated transcripts, with expected up-regulation of cyclo-oxygenase 2 in M1 cells and unexpected cyclo-oxygenase 1 up-regulation in M2 cells. 5) Each step is characterized by a different repertoire of G protein-coupled receptors, with five nucleotide receptors as novel M2-associated genes. 6) The chemokinome of polarized macrophages is profoundly diverse and new differentially expressed chemokines are reported. Thus, transcriptome profiling reveals novel molecules and signatures associated with human monocyte-to-macrophage differentiation and polarized activation which may represent candidate targets in pathophysiology.
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Dendritic cells (DC) play a central role in the development of an adaptive immune response against tumour. In addition to its role in antigen presentation, DC also possesses cytotoxic activity against tumour cells. We have earlier shown phenotypic and functional maturation of bone marrow derived dendritic cells (BMDC) by G1-4A, an arabinogalactan derived from Tinospora cordifolia. In this study, we have investigated the killer phenotype of BMDC matured in the presence of G1-4A, [mBMDC (G1-4A)] on tumour cells. We have observed several fold increase in killing of tumour cells by mBMDC (G1-4A). The tumouricidal activity was not specific to syngeneic tumour cells but could kill xenogenic tumours also. Nitric oxide released by mBMDC (G1-4A) generates peroxynitrite in tumour cells and is responsible for killing of target cells. This killing was completely abrogated by inducible nitric oxide synthase (iNOS) inhibitor 1400W and NADPH oxidase inhibitor apocyanin. The killed target cells are phagocytosed by BMDC which further activate syngeneic cytotoxic T cells. These results thus show that G1-4A treated mBMDC acquire killer phenotype along with maturation which plays an important role in activation of cytotoxic T cells.
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Pro-inflammatory macrophages are involved in vascular inflammation and serve as the major effector cells in the pathophysiology of atherosclerosis. Phosphatidylcholine (PC) is a major phospholipid moiety affixed to oxidized low-density lipoprotein (oxLDL) and thought to play important roles in the development of atherosclerosis. In this study we described that a bioactive lipid derivative, lysophosphatidylcholine (lysoPC), generated from hydrolysis of the PC moiety of oxidized LDL, promoted and stabilized a strong M1 phenotype in macrophage polarization. Another derivative, 9-hydroxyoctadecadienoic Acid (9-HODE), did not show the similar biological function. Blockade of G protein coupled receptor, G2A, which mediates the signal transduction of lysoPC, diminished the effects of lysoPC on the macrophage polarization toward M1 phenotype. The results provide insights into the new mechanism on how oxidized LDL participates in tissue inflammation in atherosclerosis.
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Chlamydia are intracellular bacteria which infect many vertebrates, including humans. They cause a myriad of severe diseases, ranging from asymptomatic infection to pneumonia, blindness or infertility. IFN-γ plays an important role in defense against acute infection and in the establishment of persistence. Chlamydia have evolved mechanisms to escape IFN-γ functions. IFN-γ-mediated effector mechanisms may involve effects on the metabolism of tryptophan or iron, on the inducible NO synthase (iNOS), on the secretion of chemokines and adhesion molecules or on the regulation of T-cell activities. IFN-γ is secreted by the innate and the adaptive arms of the immune system. Within the former, Chlamydia-infected macrophages express IFN-γ that in turn mediates resistance to infection. IFN-α/β are pivotal for both IFN-γ- and iNOS-mediated resistance to chlamydial infection in macrophages.
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Polarized activation of cells of the monocyte-macrophage lineage into M1 and M2 cells is an operationally useful, simplified descriptor of the functional plasticity of these cells. Ghassabeh and colleagues now put to the test the actual in vivo validity and significance of the M1/M2 paradigm.
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Mononuclear phagocytes play a fundamental role in the tissue homeostasis and innate defenses against viruses and other microbial pathogens. In addition, they are likely involved in several steps of cancer development. Circulating monocytes and tissue macrophages are target cells of viral infections, including human cytomegalovirus, human herpes virus 8, and the HIV, and alterations of their functional and phenotypic properties are likely involved in many tissue-degenerative diseases, including atherosclerosis and cancer. Different tissue microenvironments as well as their pathological alterations can profoundly affect the polarization state of macrophages toward the extreme phenotypes conventionally termed M1 and M2. Thus, targeting disease-associated macrophages is considered a potential approach particularly in the context of cancer-associated tumor-associated macrophages, supporting malignant cell growth and progression toward a metastatic phenotype. Of note is the fact that tumor-associated macrophages isolated from established tumors display phenotypic and functional features similar to those of in vitro-derived M2-polarized cells. Concerning HIV-1 infection, viral eradication strategies in the context of combination antiretroviral therapy should also consider the possibility to deplete, at least transiently, certain mononuclear phagocytes subsets, although the possibility of distinguishing those that are either infected or pathogenically altered remains a goal of future research. In the present review, we will focus on the recent literature concerning the role of human macrophage polarization in viral infections and cancer.
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We report, herein, an attempt to determine whether an IL-10-induced immunological state affects the response of macrophages against Salmonella Typhimurium (ST). Pretreatment with mrIL-10 induced the intracellular invasion of ST into macrophages in a dose-dependent manner. It also activated AKT phosphorylation, cyclin D1, Bcl-X(L), and COX-2 upon ST infection, which may correlate with Salmonella's survival within the macrophages. However, I-κB phosphorylation was shown to be inhibited, along with the expression of TNF-α and MIP-2α mRNA. Therefore, IL-10 not only suppresses the bactericidal response of macrophages against ST, but also ultimately causes infected macrophages to function as hosts for ST replication.
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Plasticity is a hallmark of cells of the myelomonocytic lineage. In response to innate recognition or signals from lymphocyte subsets, mononuclear phagocytes undergo adaptive responses. Shaping of monocyte-macrophage function is an essential component of resistance to pathogens, tissue damage and repair. The orchestration of myelomonocytic cell function is a key element that links inflammation and cancer and provides a paradigm for macrophage plasticity and function. A better understanding of the molecular basis of myelomonocytic cell plasticity will open new vistas in immunopathology and therapeutic intervention.
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The concept of an alternative pathway of macrophage activation has stimulated interest in its definition, mechanism, and functional significance in homeostasis and disease. We assess recent research in this field, argue for a restricted definition, and explore pathways by which the T helper 2 (Th2) cell cytokines interleukin-4 (IL-4) and IL-13 mediate their effects on macrophage cell biology, their biosynthesis, and responses to a normal and pathological microenvironment. The stage is now set to gain deeper insights into the role of alternatively activated macrophages in immunobiology.
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G1-4A, a polysaccharide from an Indian medicinal plant Tinospora cordifolia, was recently shown to protect mice against septic shock by modulating the proinflammatory cytokines. G1-4A also activated B cells polyclonally. The present report describes in detail the molecular events associated with G1-4A-induced immunomodulation in vitro and in vivo. G1-4A treatment led to an increase in the CD69 expression in lymphocytes. G1-4A-induced proliferation of B cells was completely inhibited by PI3K inhibitor Ly294002, mTOR inhibitor rapamycin and NF-kappaB inhibitor plumbagin. Akt, ERK and JNK were activated by G1-4A which finally resulted in the activation of IKK, degradation of IkappaB-alpha and translocation of NF-kappaB to the nucleus. Administration of G1-4A to mice led to splenomegaly and an increase in the numbers of T cells, B cells and macrophages. This increase in spleen cellularity was due to in vivo proliferation of lymphocytes and upregulation of anti-apoptotic genes. Anti-TLR4-MD2 complex antibody inhibited G1-4A-induced B cell proliferation and degradation of IkappaB-alpha suggesting that TLR-4 was a receptor for G1-4A on B cells. Activation of RAW 264.7 macrophages by G1-4A was found to be dependent on ERK and NF-kappaB-mediated signals. The phagocytosis index in peritoneal exudate cells (PEC) isolated from G1-4A treated mice was significantly higher as compared to that in PEC from control mice. G1-4A administration also increased the number of CD11b(+) cells in the PEC without an increase in the total number of PEC. Thus the present understanding of the molecular mechanism of action of G1-4A, a novel non-microbial TLR4 agonist, will pave the way for its application as an immunomodulator and adjuvant.
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Macrophages are innate immune cells with well-established roles in the primary response to pathogens, but also in tissue homeostasis, coordination of the adaptive immune response, inflammation, resolution, and repair. These cells recognize danger signals through receptors capable of inducing specialized activation programs. The classically known macrophage activation is induced by IFN-gamma, which triggers a harsh proinflammatory response that is required to kill intracellular pathogens. Macrophages also undergo alternative activation by IL-4 and IL-13, which trigger a different phenotype that is important for the immune response to parasites. Here we review the cellular sources of these cytokines, receptor signaling pathways, and induced markers and gene signatures. We draw attention to discrepancies found between mouse and human models of alternative activation. The evidence for in vivo alternative activation of macrophages is also analyzed, with nematode infection as prototypic disease. Finally, we revisit the concept of macrophage activation in the context of the immune response.
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Tumor necrosis factor-alpha (TNFalpha) and nitric oxide (NO), the product of inducible NO synthase (iNOS), mediate inflammatory and immune responses in the CNS under a variety of neuropathological situations. They are produced mainly by "activated" astrocytes and microglia, the two immune regulatory cells of the CNS. In this study we have examined the regulation of TNFalpha and iNOS gene expression in endotoxin-stimulated primary glial cultures, focusing on the role of mitogen-activated protein (MAP) kinase cascades. The bacterial lipopolysaccharide (LPS) was able to activate extracellular signal-regulated kinase (ERK) and p38 kinase subgroups of MAP kinases in microglia and astrocytes. ERK activation was sensitive to PD98059, the kinase inhibitor that is specific for ERK kinase. The activity of p38 kinase was inhibited by SB203580, a member of the novel class of cytokine suppressive anti-inflammatory drugs (CSAIDs), as revealed by blocked activation of the downstream kinase, MAP kinase-activated protein kinase-2. The treatment of glial cells with either LPS alone (microglia) or a combination of LPS and interferon-gamma (astrocytes) resulted in an induced production of NO and TNFalpha. The two kinase inhibitors, at micromolar concentrations, individually suppressed and, in combination, almost completely blocked glial production of NO and the expression of iNOS and TNFalpha, as determined by Western blot analysis. Reverse transcriptase-PCR analysis showed changes in iNOS mRNA levels that paralleled iNOS protein and NO while indicating a lack of effect of either of the kinase inhibitors on TNFalpha mRNA expression. The results demonstrate key roles for ERK and p38 MAP kinase cascades in the transcriptional and post-transcriptional regulation of iNOS and TNFalpha gene expression in endotoxin-activated glial cells.
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An arabinogalactan of mean M(r) 2.2 x 10(6) has been isolated from the dried stems of Tinospora cordifolia and examined by methylation analysis, partial hydrolysis and carboxyl reduction. Purified polysaccharide showed polyclonal mitogenic activity against B-cells, their proliferation did not require macrophages.
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To study whether there are differences in the immunohistochemical staining of CD8, CD45R0, and CD68 of immune cells in regional lymph node metastases from colorectal cancer that are of potential interest in prognostic prediction. Analysis of archival specimens from 93 patients operated on for colorectal cancer (based on monoclonal antibodies, the ABC technique, and semiquantitative classification). There was a significant difference in survival time between patients with respect to the number of positive immune cells. The cancer-specific 5-year survival rate was 77% for patients with high numbers of CD8+ cells, compared to 33% for those with lower numbers. The corresponding figures for patients with CD45R0+ cells were 66% vs. 33%, and for patients with CD68+ cells 60% vs. 38%. Significant differences remained among the 74 patients without adjuvant radio/chemotherapy regarding CD8 and CD45R0 but not CD68. The presence of CD8+, CD45R0+, and CD68+ immune cells in regional lymph node metastases may serve as predictors of patients survival in colorectal cancer Dukes' stage C.
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Chlamydia are intracellular bacteria which infect many vertebrates, including humans. They cause a myriad of severe diseases, ranging from asymptomatic infection to pneumonia, blindness or infertility. IFN-gamma plays an important role in defense against acute infection and in the establishment of persistence. Chlamydia have evolved mechanisms to escape IFN-gamma functions. IFN-gamma-mediated effector mechanisms may involve effects on the metabolism of tryptophan or iron, on the inducible NO synthase (iNOS), on the secretion of chemokines and adhesion molecules or on the regulation of T-cell activities. IFN-gamma is secreted by the innate and the adaptive arms of the immune system. Within the former, Chlamydia-infected macrophages express IFN-gamma that in turn mediates resistance to infection. IFN-alpha/beta are pivotal for both IFN-gamma- and iNOS-mediated resistance to chlamydial infection in macrophages.
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Two active polysaccharide fractions (SF1 and SF2) purified from dried safflower petals (Carthamus tinctorius L.) stimulated the synthesis of various cytokines by peritoneal macrophages. In a number of cell types, SF1 and SF2 induced a rapid degradation of IkappaB alpha essential for the activation of the transcription factor NF-kappaB. Toll-like receptor 4 (TLR4), but not TLR2, was expressed in all cell lines that responded to SF1 and SF2. Enforced expression of TLR4 and MD-2 rendered responsiveness to SF1 and SF2. Moreover, these safflower polysaccharides failed to induce the production of TNF-alpha and NO by peritoneal macrophages prepared from C3H/HeJ mice that have a point mutation in the Tlr4 gene. Thus, these observations clearly indicate that safflower polysaccharides activate the NF-kappaB signaling pathway via TLR4.
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One of the functions of macrophages is to provide a defense mechanism against tumor cells. In the last decades the mechanism of tumor cell killing by macrophages have been studied extensively. The tumor cytotoxic function of macrophages requires stimulation either with bacterial cell wall products such as lipopolysaccharide (LPS) or muramyldipeptide (MDP) or with cytokines such as interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Activated macrophages secrete several substances that are directly involved in tumor cell killing i.e. tumor necrosis factor (TNF) and nitric oxide (NO). On the other hand, substances are secreted that are able to stimulate tumor cell growth, depending on the stage and the nature of the tumor. Several clinical trials have been performed aiming at the activation of macrophages or dendritic cells, a subpopulation of the macrophages. In this review we will summarize and discuss experimental studies and clinical trials based on the activation of macrophages.
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Invading pathogens are controlled by the innate and adaptive arms of the immune system. Adaptive immunity, which is mediated by B and T lymphocytes, recognises pathogens by rearranged high affinity receptors. However, the establishment of adaptive immunity is often not rapid enough to eradicate microorganisms as it involves cell proliferation, gene activation and protein synthesis. More rapid defense mechanisms are provided by innate immunity, which recognises invading pathogens by germ-line-encoded pattern recognition receptors (PRR). Recent evidence shows that this recognition can mainly be attributed to the family of TOLL-like receptors (TLR). Binding of pathogen-associated molecular patterns (PAMP) to TLR induces the production of reactive oxygen and nitrogen intermediates (ROI and RNI), pro-inflammatory cytokines, and up-regulates expression of co-stimulatory molecules, subsequently initiating the adaptive immunity. In this review, we will summarize the discovery and the critical roles of the TLR family in host defense, briefly allude to signaling mechanisms mediating the response to TLR ligands, and will provide an update on current knowledge regarding the ligand specificity of these receptors and their role in immunity of domestic animals, particularly cattle.
Article
Macrophage heterogeneity used to be a research topic on which the careers of many postdoctoral fellows were misspent. The lack of definitive markers and dubious biochemical assays prevented the unequivocal identification of specific cell subsets. There has now been significant progress in establishing the heterogeneity of activated macrophages. There are at least three distinct populations of macrophages, and each cell type appears to have different biological roles. The interplay among these populations of cells may help to shape not only the magnitude but also the character of the immune response. The manipulation of these cells may lead to new approaches to treat or prevent disease.
Article
Members of the Toll-like receptor (TLR) family recognize conserved microbial structures, such as bacterial lipopolysaccharide and viral double-stranded RNA, and activate signaling pathways that result in immune responses against microbial infections. All TLRs activate MyD88-dependent pathways to induce a core set of stereotyped responses, such as inflammation. However, individual TLRs can also induce immune responses that are tailored to a given microbial infection. Thus, these receptors are involved in both innate and adaptive immune responses. The mechanisms and components of these varied responses are only partly understood. Given the importance of TLRs in host defense, dissection of the pathways they activate has become an important emerging research focus. TLRs and their pathways are numerous; Science's Signal Transduction Knowledge Environment's TLR Connections Map provides an immediate, clear overview of the known components and relations of this complex system.
Article
We investigated the mechanism of the immunomodulatory action of polysaccharide (ASP) isolated from a cell culture of Acanthopanax senticosus. ASP was found to directly increase the proliferation and differentiation of B cells, and the cytokine production of macrophage, but not the proliferation and cytokine production of T cells. Since ASP cannot penetrate the cell membrane due to its large molecular mass, such cellular activation may be caused by the surface binding of ASP to receptors expressed on B cells and macrophages. The possibility that TLRs, which are known to be involved in immune-related responses, may be the receptor(s) of ASP was investigated. The immunomodulating activities of ASP on the B cells and macrophages of C3H/HeJ mice, expressing a defective toll-like receptor (TLR)-4, were decreased versus the corresponding cells from C3H/HeN mice. In addition, the activities of ASP on B cells and macrophages were significantly reduced by treating the cells with antibodies to TLR4 and TLR2 prior to ASP, suggesting that both of them are the possible receptors of ASP. The ligation of TLRs induced by ASP was able to activate mitogen-activated protein kinases (MAPKs), such as Erk1/2, p38 and JNK, and the transcription factor NF-kappaB. Although ASP was shown to activate the TLR signaling cascades in the same manner as lipopolysaccharide (LPS), these two could be differentiated by the finding that polymyxin B (PMB), a specific inhibitor of LPS, did not significantly affect the activities of ASP on B cells and macrophages. Taken together, our results demonstrate that ASP, isolated from a cell culture of A. senticosus, activates B cells and macrophages by interacting with TLRs and leading to the subsequent activation of mitogen-activated protein kinases and NF-kappaB.
Article
Platycodon grandiflorum, a traditional oriental herbal medicine, is known to have immunostimulatory and antitumor effects. PG, a polysaccharide isolated from P. grandiflorum, has been reported to activate macrophages and B cells. Here, we investigated the membrane receptor and intracellular signaling responsible for the activation of macrophages by PG. PG induced the production of nitric oxide (NO) and the mRNA expression of iNOS in RAW 264.7 cells. To investigate the membrane receptor involved in the activation of NO production, we examined the effect of PG on the production of NO in mouse peritoneal macrophages isolated from wild type C3H/HeN and functional Toll-like receptor 4 (TLR4)-deficient C3H/HeJ mice. PG induced NO production by macrophages isolated from C3H/HeN mice, but had no effect on NO production by macrophages isolated from C3H/HeJ mice. Moreover, monoclonal antibodies directed to TLR4 blocked PG-mediated induction of NO production. In addition, LBP and sCD14 was also found to be involved in the activation of NO production by PG. To further investigate, we examined the effect of PG on the activation of DNA binding of NF-kappa B, which is a downstream transcriptional regulator of TLR4. PG caused degradation of I kappa B and activation of DNA binding of NF-kappa B. In addition, TPCK, a specific NF-kappa B inhibitor, abolished PG-mediated induction of DNA binding of NF-kappa B, production of NO and mRNA expression of iNOS, demonstrating the involvement of NF-kappa B in PG-mediated macrophage activation. Taken together, these results suggest that PG-mediated induction of NO production and iNOS mRNA expression in macrophages is mediated, at least in part, by TLR4/NF-kappa B signaling pathway.
Article
Toll-like receptors are of key importance in the recognition of and response to infectious agents by cells of the innate immune system. TLR mRNA expression and TLR-mediated functions were determined in bovine macrophages (MPhi) infected with bovine viral diarrhea virus (BVDV) or stimulated with interferon-gamma (IFN-gamma) in order to see whether they are correlated under these conditions. As parameters quantitative real time RT-PCR (QRT-PCR) for TLR2, TLR3 and TLR4, NO and TNF production were measured. Triggering of bovine MPhi with bona fide TLR2 and TLR4 agonists (lipopolysaccharide, lipoteichoic acid, peptidoglycan, lipopetide) led to NO and TNF production but neither TLR3 nor TLR9 agonists (double-stranded RNA, CpG DNA) showed this effect. The mRNA expression of TLR2, TLR3 and TLR4 was neither influenced by MPhi costimulation with IFN-gamma nor by MPhi preinfection with BVDV nor by the ligands themselves. However, NO production induced by TLR2 or TLR4 agonists was strongly modulated either by IFN-gamma costimulation or BVDV preinfection. Thus costimulation of MPhi with IFN-gamma resulted in an increase of both NO synthesis and TNF expression by cells stimulated simultaneously by TLR2 or TLR4 agonists. Preinfection of bovine MPhi by BVDV resulted in upregulation of TLR2- and TLR4-mediated NO synthesis. Collectively, these data show that TLR-mediated functions may be modulated by viral infection or activation via IFN-gamma of MPhi whereas the mRNA concentrations of relevant TLR members were not significantly influenced. Thus, the amount of TLR2, TLR3 and TLR4 mRNA transcripts is stable at least under the conditions tested. More importantly, modulation of TLR-mediated responses was dissociated from mRNA expression of TLR members.
Article
Heterogeneity and plasticity are hallmarks of cells belonging to the monocyte-macrophage lineage (Gordon, 2003, Mantovani et al., 2002 and Mantovani et al., 2004). Lineage-defined populations of mononuclear phagocytes have not been identified, but short-lived, circulating precursor monocyte subsets characterized by differential expression of the FcγRIII receptor (CD16) and of chemokine receptors (CCR2, CX3CR1, and CCR8), as well as by different functional properties, have been described. Macrophage plasticity is demonstrated by acquisition of distinct morphological and functional properties directed by particular tissues (e.g., the lung alveolar macrophage) and immunological microenvironment.
Article
Macrophages play a significant role in the host defence mechanism. When activated they can produce reactive oxygen species (ROS) as well as related reactive nitrogen species (RNS). ROS are produced via NAD(P)H oxidase which catalyzes superoxide (O2-) formation. It is subsequently converted to hydrogen peroxide (H2O2) by either spontaneous or enzyme-mediated dismutation. Nitric oxide synthase (NOS) catalyzes nitric oxide (NO) formation. Canova (CA) is a Brazilian medication produced with homeopathic techniques, composed of Aconitum, Thuya, Bryonia, Arsenicum, Lachesis in distilled water containing less than 1% ethanol. Previous studies demonstrated that CA is neither toxic nor mutagenic and activates macrophages decreasing the tumor necrosis factor-alpha (TNFalpha) production. In this assay we showed that macrophages triggered with Canova increased NAD(P)H oxidase activity as well as that of iNOS, consequently producing ROS and NO respectively. Cytochrome oxidase and peroxisomes activities were inhibited by NO. As NO and O2- are being produced at the same time, formation of peroxynitrite (ONOO-) may be occurring. A potential explanation is provided on how treatment with Canova may enhance immune functions which could be particularly important in the cytotoxic actions of macrophages. CA can be considered as a new adjuvant therapeutic approach to known therapies.