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Publications (146)
Herpes simplex virus type 1 (HSV-1) is a widespread contagious pathogen, mostly causing mild symptoms on the mucosal entry side. However, systemic distribution, in particular upon reactivation of the virus in immunocompromised patients, may trigger an innate immune response and induce damage of organs. In these conditions, HSV-1 may infect vascular...
Tumors are a highly heterogeneous mass of tissue showing distinct therapy responses. In particular, the therapeutic outcome of tumor hyperthermia treatments has been inconsistent, presumably due to tumor versus endothelial cell cross-talks related to the treatment temperature and the tumor tissue environment. Here, we investigated the impact of the...
Vascular aging is based on the development of endothelial dysfunction, which is thought to be promoted by senescent cells accumulating in aged tissues and is possibly affected by their environment via inflammatory mediators and oxidative stress. Senescence appears to be closely interlinked with changes in cell metabolism. Here, we describe an upreg...
Aims
Septic cardiomyopathy is a severe complication of sepsis and septic shock. This study aimed to evaluate the role of thrombomodulin and its lectin-like domain (LLD-TM) in the development of septic cardiomyopathy and the link between LLD-TM, HMGB-1, and toll-like receptors 2/4 (TLR 2/4) to intracellular mechanisms resulting in reduced cardiac fu...
The AMP-activated protein kinase (AMPK) αβγ heterotrimer is a primary cellular energy sensor and central regulator of energy homeostasis. Activating skeletal muscle AMPK with small molecule drugs improves glucose uptake and provides opportunity for new strategies to treat type 2 diabetes and insulin resistance, with recent genetic and pharmacologic...
Posttranslational mechanisms play a key role in modifying the abundance and function of cellular proteins. Among these, modification by advanced glycation end products has been shown to accumulate during aging and age-associated diseases but specific protein targets and functional consequences remain largely unexplored. Here, we devise a proteomic...
Influenza virus (IV) infections are considered to cause severe diseases of the respiratory tract. Beyond mild symptoms, the infection can lead to respiratory distress syndrome and multiple organ failure. Occurrence of resistant seasonal and pandemic strains against the currently licensed antiviral medications points to the urgent need for new and a...
Microglia, the innate immune cells of the CNS, exhibit long-term response changes indicative of innate immune memory (IIM). Our previous studies revealed IIM patterns of microglia with opposing immune phenotypes: trained immunity after a low dose and immune tolerance after a high dose challenge with pathogen-associated molecular patterns (PAMP). Co...
Infections with severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2) can be asymptomatic, but they can also be accompanied by a variety of symptoms that result in mild to severe coronavirus disease-19 (COVID-19) and are sometimes associated with systemic symptoms. Although the viral infection originates in the respiratory system, it is uncl...
Background & Aims
Retention of bile acids in the blood is a hallmark of liver failure. Recent studies have shown that elevated serum bile acid levels correlate with bacterial infection and an increased mortality. However, the mechanisms by which circulating bile acids influence patient outcomes are still elusive.
Methods
Serum bile acid profiles i...
The prognosis of late-stage epithelial ovarian cancer (EOC) patients is affected by chemotherapy response and the malignant potential of the tumor cells. In earlier work, we identified hypermethylation of the runt-related transcription factor 3 gene (RUNX3) as a prognostic biomarker and contrary functions of transcript variants (TV1 and TV2) in A27...
Posttranslational mechanisms play a key role in modifying the abundance and function of cellular proteins. Among these, modification by advanced glycation end products (AGEs) has been shown to accumulate during aging and age-associated diseases but specific protein targets and functional consequences remain largely unexplored. Here, we devised a pr...
Activation of AMP-activated protein kinase (AMPK) in endothelial cells by vascular endothelial growth factor (VEGF) via the Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2) represents a pro-angiogenic pathway, whose regulation and function is incompletely understood. This study investigates whether the VEGF/AMPK pathway is regulated by cA...
Infections with SARS-CoV-2 lead to mild to severe coronavirus disease-19 (COVID-19) with systemic symptoms. Although the viral infection originates in the respiratory system, it is unclear how the virus can overcome the alveolar barrier, which is observed in severe COVID-19 disease courses.
To elucidate the viral effects on the barrier integrity an...
Pneumonia is the leading cause of hospitalization worldwide. Besides viruses, bacterial co-infections dramatically exacerbate infection. In general, surfactant protein-A (SP-A) represents a first line of immune defense. In this study, we analyzed whether influenza A virus (IAV) and/or Staphylococcus aureus (S. aureus) infections affect SP-A express...
The breakdown of the endothelial cell (EC) barrier contributes significantly to sepsis mortality. Sphingosine 1-phosphate (S1P) is one of the most effective EC barrier-stabilizing signaling molecules. Stabilization is mainly transduced via the S1P receptor type 1 (S1PR1). Here, we demonstrate that S1P was autonomously produced by ECs. S1P secretion...
AMP-activated protein kinase (AMPK) is activated by vascular endothelial growth factor (VEGF) in endothelial cells and it is significantly involved in VEGF-induced angiogenesis. This study investigates whether the VEGF/AMPK pathway regulates autophagy in endothelial cells and whether this is linked to its pro-angiogenic role. We show that VEGF lead...
Pneumonia is one of the most common infectious diseases worldwide. The influenza virus (IV) can cause severe epidemics, which results in significant morbidity and mortality. Beyond the virulence of the virus itself, epidemiological data suggest that bacterial co-infections are the major cause of increased mortality. In this context, Staphylococcus...
Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor family playing pivotal roles in regulating glucose and lipid metabolism as well as inflammation. While characterizing potential PPARγ ligand activity of natural compounds in macrophages we investigated their influence on the expression of adipophilin (pe...
Infections with the herpes simplex virus type 1 (HSV-1) are common and widespread. Most infections remain undetected but severe forms may develop in newborns and in immunocompromised patients. Moreover, HSV-1 might be involved in the pathogenesis of atherosclerosis, which may include viral infection of the endothelium. Antiviral therapy is efficien...
Background:
Diabetes mellitus is an important cardiovascular risk factor characterized by elevated plasma glucose levels. High glucose (HG) negatively influences endothelial cell (EC) function, which is characterized by the inability of ECs to respond to vascular endothelial growth factor (VEGF-A) stimulation. We aimed to identify potential strate...
Sepsis-induced myocardial depression (SIMD) is an early and frequent consequence of the infection-induced systemic inflammatory response syndrome. In homiotherms, variations in ambient temperature (Ta) outside the thermoneutral zone induce thermoregulatory responses mainly driven by a gradually increased sympathetic activity, which may affect disea...
Glucan derived from cell walls of Candida albicans is a potent immune modulator. It has been shown to induce trained immunity in monocytes via epigenetic and metabolic reprogramming and to protect from lethal sepsis if applied prior to infection. Since β-glucan-trained monocytes have not been classified within the system of mononuclear phagocytes w...
Glucan derived from cell walls of Candida albicans is a potent immune modulator. It has been shown to induce trained immunity in monocytes via epigenetic and metabolic reprogramming and to protect from lethal sepsis if applied prior to infection. Since β-glucan-trained monocytes have not been classified within the system of mononuclear phagocytes w...
Glucan derived from cell walls of Candida albicans is a potent immune modulator. It has been shown to induce trained immunity in monocytes via epigenetic and metabolic reprogramming and to protect from lethal sepsis if applied prior to infection. Since β-glucan-trained monocytes have not been classified within the system of mononuclear phagocytes w...
Microglia, the key innate immune cells in the brain, have been reported to drive brain aging and neurodegenerative disorders; however, few studies have analyzed microglial senescence and the impact of aging on the properties of microglia. In the present study, we characterized senescence- and aging-associated phenotypes of murine brain microglia us...
The human cytomegalovirus (HCMV) is a common pathogen, which causes severe or even deadly diseases in immunocompromised patients. In addition, congenital HCMV infection represents a major health concern affecting especially the lung tissue of the susceptible individuals. Antivirals are a useful strategy to treat HCMV-caused diseases. However, all a...
The role of AMPK in angiogenesis can be studied using in vitro and in vivo assays. The endothelial spheroid assay is a robust three-dimensional in vitro test, which allows investigation of tubular morphogenesis by integrating cell-cell as well as cell-matrix interactions. The Matrigel plug assay validates the process of angiogenesis in vivo and all...
Senescence is thought to contribute to endothelial dysfunction, which ultimately leads to development of cardiovascular disease. The current project characterizes proteasomal protein degradation in endothelial cells undergoing replicative or stress-induced senescence in vitro or chronological ageing in vivo.
Our results demonstrate that human endot...
Background:
Activation of AMP-activated protein kinase (AMPK) in endothelial cells regulates energy homeostasis, stress protection and angiogenesis, but the underlying mechanisms are incompletely understood. We identified glutamine:fructose-6-phosphate amidotransferase 1 (GFAT1) as an AMPK substrate. GFAT1 is the rate-limiting enzyme in the hexosam...
Tularemia is a highly contagious infectious zoonosis caused by the bacterial agent Francisella tularensis. The aim of this study was to investigate the presence of antibodies to Francisella tularensis in febrile patients in northeastern Kenya. During 2014-2015, 730 patients were screened for anti-Francisella tularensis antibodies using a combinatio...
Activation of AMP-activated protein kinase (AMPK) in endothelial cells regulates energy homeostasis, stress protection and angiogenesis, but the underlying mechanisms are incompletely understood. Using a label-free phosphoproteomic analysis, we identified glutamine:fructose-6-phosphate amidotransferase 1 (GFAT1) as an AMPK substrate. GFAT1 is the r...
Several bacteria are adapted to colonize and live together with multicellular organisms. There are some pathogenic bacteria that are even able to invade eukaryotic cells for different purposes, usually to escape the immune response or antibiotic treatment, but also to take advantage of growth in the nutrient rich host cell environment. Intracellula...
During 2014–2015, patients in northeastern Kenya were assessed for brucellosis and characteristics that might help clinicians identify brucellosis. Among 146 confirmed brucellosis patients, 29 (20%) had negative serologic tests. No clinical feature was a good indicator of infection, which was associated with animal contact and drinking raw milk.
During 2014–2015, patients in northeastern Kenya were assessed for brucellosis and characteristics that might help clinicians identify brucellosis. Among 146 confirmed brucellosis patients, 29 (20%) had negative serologic tests. No clinical feature was a good indicator of infection, which was associated with animal contact and drinking raw milk. ©...
Primers and probes for Brucella genus and species-specific quantitative PCR on specimens from brucellosis patients, Wajir and Garissa hospitals, northeastern Kenya, 2014–2015. Characteristics of brucellosis patients. Sensitivity and specificity of clinical diagnosis compared with laboratory-confirmed diagnosis of brucellosis.
Hypertrophic growth is a response of the heart to increased mechanical load or physiological stress. Thereby, cardiomyocytes grow in length and/or width to maintain cardiac pump function. Major signaling pathways involved in cardiomyocyte growth and remodeling have been identified during recent years including calcineurin–NFAT and PI3K–Akt signalin...
Background & aims:
Molecular adaptations in human nonalcoholic fatty liver disease (NAFLD) are incompletely understood. This study investigated main gene categories related to hepatic de novo lipogenesis (DNL) and lipid oxidation capacity.
Methods:
Liver specimens of 48 subjects were histologically classified according to steatosis severity. In...
Background
Brucellosis is a debilitating zoonotic disease affecting humans and animals. A comprehensive, evidence-based assessment of literature and officially available data on animal and human brucellosis for Kenya are missing. The aim of the current review is to provide frequency estimates of brucellosis in humans, animals and risk factors for h...
Background:
Q fever in Kenya is poorly reported and its surveillance is highly neglected. Standard empiric treatment for febrile patients admitted to hospitals is antimalarials or penicillin-based antibiotics, which have no activity against Coxiella burnetii. This study aimed to assess the seroprevalence and the predisposing risk factors for Q fev...
Background
Q fever is a neglected zoonosis caused by the bacterium Coxiella burnetii. The knowledge of the epidemiology of Q fever in Kenya is limited with no attention to control and prevention programs. The purpose of this review is to understand the situation of Q fever in human and animal populations in Kenya in the past 60 years, and help iden...
Background:
Nonalcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) are frequent comorbidities in perioperative patients. However, the predictive role of the hepatokine fetuin A was not evaluated in this collective.
Objective:
To study fetuin A as predictor of NAFLD/NASH in preoperative patients.
Methods:
58 subjects were included....
The mammalian target of rapamycin complex 1 (mTORC1) is known to be a central cellular nutrient sensor and master regulator of protein metabolism, and therefore indispensable for normal embryonic development. We showed previously in a diabetic pregnancy that embryonic mTORC1 phosphorylation is increased in case of maternal hyperglycaemia and hypoin...
Sepsis-induced myocardial depression (SIMD), an early and frequent event of infection-induced systemic inflammatory response syndrome (SIRS), is characterized by reduced contractility irrespective of enhanced adrenergic stimulation. Phosphoinositide-3 kinase γ (PI3Kγ) is known to prevent β-adrenergic overstimulation via its scaffold function by act...
The administration of drugs to inhibit metabolic pathways not only reduces the risk of obesity-induced diseases in humans but may also hamper the replication of different viral pathogens. In order to investigate the value of the US Food and Drug Administration-approved anti-obesity drug orlistat in view of its anti-viral activity against different...
Staphylococcus aureus is one of the most frequent human pathogens that can also act as facultative intracellular pathogen causing infections that are extremely difficult to treat. Only little is known about the pathogen's intracellular adaptation strategies to escape the host's response. Here, we present an advanced Raman-based imaging approach pro...
Natural hemozoin, nHZ, is avidly phagocytosed in vivo and in vitro by human monocytes. The persistence of the undigested beta-hematin core of nHZ in the phagocyte lysosome for long periods of time modifies several cellular immune functions. Here we show that nHZ phagocytosis by human primary monocytes severely impaired their chemotactic motility to...
After successful invasion of susceptible hosts, systemic distribution of coxsackievirus B3 (CVB3) most likely requires interactions with the endothelial system. Thereby, infection of endothelial cells occurs directly or viruses and/or virus-infected leukocytes migrate through the endothelial barrier. Many of these processes have not been studied so...
Adipose tissue derived factors link non-alcoholic fatty liver disease (NAFLD) with obesity, which was also reported for circulating chemerin. Otherwise, hepatic chemerin and CMKLR1 mRNA expression have not yet been studied in an extensively characterized patient collective.
Cross-sectional and experimental study.
Liver was harvested from n = 47 sub...
Allgemeine Substanzbeschreibung Vorkommen und Verwendung hinsichtlich Lebensmittel und -gruppen Verbreitung in Lebensmitteln und analytischer Nachweis Kinetik und innere Exposition Wirkungen Bewertung des Gefährdungspotenzials Grenzwerte, Richtlinien, Empfehlungen, Vorsorgemaßnahmen Zusammenfassung Literatur
The study was aimed at determining the vascular expression of oncofetal fibronectin (oncfFn) and tenascin-C (oncfTn-C) isoforms in renal cell carcinoma (RCC) and its metastases which are well-known targets for antibody-based pharmacodelivery. Furthermore, the influence of tumour cells on endothelial mRNA expression of these molecules was investigat...
Ascorbic acid (AA) increases cardiomyogenesis of embryonic stem (ES) cells. Herein we show that treatment of mouse ES cells with AA enhanced cardiac differentiation accompanied by an upregulation of the NADPH oxidase isoforms NOX2 and NOX4, phosphorylation of endothelial nitric oxide synthase (eNOS), and cyclic GMP (cGMP) formation, indicating that...
Adipose tissue-derived mesenchymal stem cells (ASCs) are a promising stem cell source for cell transplantation. We demonstrate that undifferentiated ASCs display robust oscillations of intracellular calcium [Ca(2+) ](i) which may be associated with stem cell maintenance since oscillations were absent in endothelial cell differentiation medium suppl...
Microorganisms such as Chlamydia pneumoniae have been shown to infect vascular cells and are believed to contribute to vascular inflammation and atherosclerotic plaque development. Plasma levels of oxidized low density lipoprotein (oxLDL) have received considerable attention as potential predictors of prognosis in atherosclerotic diseases. Lectin-l...
