Search results for "LIPOPOLYSACCHARIDE"
showing 10 items of 382 documents
Acute exercise activates nuclear factor (NF)-kappaB signaling pathway in rat skeletal muscle.
2004
Two studies were performed to investigate the effects of an acute bout of physical exercise on the nuclear protein kappaB (NF-kappaB) signaling pathway in rat skeletal muscle. In Study 1, a group of rats (n=6) was run on the treadmill at 25 m/min, 5% grade, for 1 h or until exhaustion (Ex), and compared with a second group (n=6) injected with two doses of pyrrolidine dithiocarbamate (PDTC, 100 mg/kg, i.p.) 24 and 1 h prior to the acute exercise bout. Three additional groups of rats (n=6) were injected with either 8 mg/kg (i.p.) of lipopolysaccharide (LPS), 1 mmol/kg (i.p.) t-butylhydroperoxide (tBHP), or saline (C) and killed at resting condition. Ex rats showed higher levels of NF-kappaB b…
Anandamide inhibits IL-12p40 production by acting on the promoter repressor element GA-12: Possible involvement of the COX-2 metabolite prostamide E 2
2007
The eCB [endoCB (cannabinoid)] system is being considered as a novel therapeutic target for immune disorders. Cytokines of the IL-12 (interleukin-12) family have essential functions in cell-mediated immunity. In the present study, we have addressed the mechanisms of action of the eCB AEA (anandamide) on the regulation of IL-12p40 in activated microglia/macrophages. We demonstrated that AEA can inhibit the expression of p35, p19 and p40 subunits, which form the biologically-active cytokines IL-12 and IL-23 in microglia stimulated with LPS (lipopolysaccharide)/IFNγ (interferon γ). Additionally, we have provided evidence that AEA reduces the transcriptional activity of the IL-12p40 gene in LPS…
Dominant negative MORT1/FADD rescues mice from CD95 and TNF-induced liver failure
2002
Derangement of the apoptotic program is considered an important cause of liver disease. It became clear that receptor-mediated apoptosis is of specific interest in this context, and CD95 and CD120a, both members of the tumor necrosis factor (TNF) receptor superfamily, are the most prominent cell death receptors involved. The death signal is induced upon ligand binding by recruitment of caspases via the adapter molecule MORT1/FADD to the receptor and their subsequent activation. To investigate the role of MORT1/FADD in hepatocyte apoptosis, we generated transgenic mice expressing liver-specific dominant negative mutant. Mice looked grossly normal; breeding and liver development were not diff…
Production of interleukin-6, tumor necrosis factor α and interleukin-10 in vitro correlates with the clinical immune defect in chronic hemodialysis p…
1995
Production of interleukin-6, tumor necrosis factor α and interleukin-10 in vitro correlates with the clinical immune defect in chronic hemodialysis patients. In patients with chronic renal failure alterations in monokine production are a common feature. Their clinical relevance has not yet been proven. We show here a correlation between an overproduction of interleukin-(IL)-6 and tumor necrosis factor alpha (TNFα) upon stimulation with LPS by mononuclear cells in vitro and the clinical grade of immunodeficiency found in these patients. Higher levels of IL-6 and TNFα were correlated with an immunocompromized state, that is, non-responsiveness to hepatitis B vaccination, whereas patients with…
Evaluation of soluble CD 14 and neopterin as serum parameters of the inflammatory activity of pulmonary sarcoidosis.
1992
CD14 represents the most specific marker for monocytes/macrophages. It has been demonstrated in vitro that monocytes/macrophages lose this antigen upon activation. Results of studies investigating the expression of membrane-bound CD14 on the surface of monocytes/macrophages in sarcoidosis patients are controversial. To investigate whether the soluble form of CD14 reflects monocyte/macrophage activation in sarcoidosis, serum levels of soluble CD14 were determined concurrently with other serum markers of monocyte/macrophage activation (neopterin, angiotensin-converting enzyme) in 50 consecutive patients with bioptically confirmed sarcoidosis. The patients were allocated to three groups accord…
Cigarette smoke increases Toll-like receptor 4 and modifies lipopolysaccharide-mediated responses in airway epithelial cells.
2008
Airway epithelium is emerging as a regulator of innate immune responses to a variety of insults including cigarette smoke. The main goal of this study was to explore the effects of cigarette smoke extracts (CSE) on Toll-like receptor (TLR) expression and activation in a human bronchial epithelial cell line (16-HBE). The CSE increased the expression of TLR4 and the lipopolysaccharide (LPS) binding, the nuclear factor-kappaB (NF-kappaB) activation, the release of interleukin-8 (IL-8) and the chemotactic activity toward neutrophils. It did not induce TLR2 expression or extracellular signal-regulated signal kinase 1/2 (ERK1/2) activation. The LPS increased the expression of TLR4 and induced bot…
The stimulation of arginine transport by TNFα in human endothelial cells depends on NF-κB activation
2004
In human saphenous vein endothelial cells (HSVECs), tumor necrosis factor-alpha (TNFalpha) and bacterial lipopolysaccharide (LPS), but neither interferon gamma (IFNgamma) nor interleukin 1beta (IL-1beta), stimulate arginine transport. The effects of TNFalpha and LPS are due solely to the enhancement of system y+ activity, whereas system y+L is substantially unaffected. TNFalpha causes an increased expression of SLC7A2/CAT-2B gene while SLC7A1/CAT-1 expression is not altered by the cytokine. The suppression of PKC-dependent transduction pathways, obtained with the inhibitor chelerytrhine, the inhibitor peptide of PKCzeta isoform, or chronic exposure to phorbol esters, does not prevent TNFalp…
Involvement of complement pathways in patients with bacterial septicemia.
2007
The complement system is a major humoral portion of the innate immune system, playing a significant role in host defence against microorganisms. The biological importance of this system is underlined by the fact that at least three different pathways for its activation exist, the classical, the MBL and the alternative pathway. To elucidate the involvement of the classical and/or the MBL pathway during bacterial septicemia, 32 patients with gram-positive and 30 patients with gram-negative bacterial infections were investigated. In patients with gram-positive bacteria, a significant consumption of C1q (p=0.005) but not of mannose-binding lectin (MBL) (p=0.2) was found during the acute phase o…
Fine-tuning nucleophosmin in macrophage differentiation and activation
2011
Abstract M-CSF–driven differentiation of peripheral blood monocytes is one of the sources of tissue macrophages. In humans and mice, the differentiation process involves the activation of caspases that cleave a limited number of proteins. One of these proteins is nucleophosmin (NPM1), a multifunctional and ubiquitous protein. Here, we show that caspases activated in monocytes exposed to M-CSF cleave NPM1 at D213 to generate a 30-kDa N-terminal fragment. The protein is further cleaved into a 20-kDa fragment, which involves cathepsin B. NPM1 fragments contribute to the limited motility, migration, and phagocytosis capabilities of resting macrophages. Their activation with lipopolysaccharides …
Alpha-defensins secreted by dysplastic granulocytes inhibit the differentiation of monocytes in chronic myelomonocytic leukemia.
2010
Abstract Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic disorder that occurs in elderly patients. One of the main diagnostic criteria is the accumulation of heterogeneous monocytes in the peripheral blood. We further explored this cellular heterogeneity and observed that part of the leukemic clone in the peripheral blood was made of immature dysplastic granulocytes with a CD14−/CD24+ phenotype. The proteome profile of these cells is dramatically distinct from that of CD14+/CD24− monocytes from CMML patients or healthy donors. More specifically, CD14−/CD24+ CMML cells synthesize and secrete large amounts of alpha-defensin 1-3 (HNP1-3). Recombinant HNPs inhibit macrophage co…