Home About us Contact
|
Home About us Contact | ||
|
|
||
LPS-induced Activation (LPS-induce + activation)
Selected AbstractsMultiple Kv1.5 targeting to membrane surface microdomains,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2008Ramón Martínez-Mármol Surface expression of voltage-dependent K+ channels (Kv) has a pivotal role in leukocyte physiology. Although little is known about the physiological role of lipid rafts, these microdomains concentrate signaling molecules and their ion channel substrates. Kv1.3 associates with Kv1.5 to form functional channels in macrophages. Different isoform stoichiometries lead to distinct heteromeric channels which may be further modulated by targeting the complex to different membrane surface microdomains. Kv1.3 targets to lipid rafts, whereas Kv1.5 localization is under debate. With this in mind, we wanted to study whether heterotetrameric Kv1.5-containing channels target to lipid rafts. While in transfected HEK-293 cells, homo- and heterotetrameric channels targeted to rafts, Kv1.5 did not target to rafts in macrophages. Therefore, Kv1.3/Kv1.5 hybrid channels are mostly concentrated in non-raft microdomains. However, LPS-induced activation, which increases the Kv1.3/Kv1.5 ratio and caveolin, targeted Kv1.5 back to lipid rafts. Moreover, Kv1.5 did not localize to low-buoyancy fractions in L6E9 skeletal myoblasts, which also coexpress both channels, heart membranes or cardiomyocyes. Coexpression of a Cav3DGV -mutant confined Kv1.5 to Cav3DGV -vesicles of HEK cells. Contrarily, coexpression of Kv,2.1 impaired the Kv1.5 targeting to raft microdomains in HEK cells. Our results indicate that Kv1.5 partnership interactions are underlying mechanisms governing channel targeting to lipid rafts. J. Cell. Physiol. 217: 667,673, 2008. © 2008 Wiley-Liss, Inc. [source] Moderate Alcohol Intake in Humans Attenuates Monocyte Inflammatory Responses: Inhibition of Nuclear Regulatory Factor Kappa B and Induction of Interleukin 10ALCOHOLISM, Issue 1 2006Pranoti Mandrekar Background: In contrast to the deleterious effects of chronic excessive alcohol consumption on the liver and cardiovascular system, modest alcohol intake, such as 1 to 2 drinks per day, has benefits on cardiovascular mortality. Little is known about the length of time or the amounts of alcohol consumed that may cause alterations in inflammatory cells such as monocytes that are crucial to atherosclerotic vascular disease. Here, we determine in vivo effects of acute alcohol consumption on inflammatory cytokine production and nuclear regulatory factor ,B (NF- ,B) binding in human monocytes. Methods: Human blood monocytes were isolated by plastic adherence before and after acute alcohol consumption (2 ml vodka/kg body weight). Lipopolysaccharide (LPS)- and superantigen-induced tumor necrosis factor , (TNF ,), interleukin (IL)-1,, and IL-10 production were then determined in monocytes by ELISA. Nuclear regulatory factor- ,B activity of monocytes before and after alcohol consumption was estimated by electromobility shift assay and promoter-driven reporter activity. I,B, was determined by Western blotting in the cytoplasmic extracts. Results: Eighteen hours after moderate alcohol consumption, we found a significant reduction in monocyte production of inflammatory mediators, TNF- , and IL-1,, in response to LPS or staphylococcal enterotoxin B stimulation. Acute alcohol consumption inhibited LPS-induced DNA binding of the p65/p50 NF- ,B in monocytes that regulates the expression of both the TNF- , and the IL-1, genes. Consistent with this, acute alcohol treatment (25 mM) significantly reduced LPS-induced activation of an NF- ,B-driven reporter gene suggesting inhibition of this proinflammatory signaling pathway. Further, LPS-induced I,B, degradation was not affected by acute alcohol consumption indicating an I,B, -independent mechanism, as observed earlier in the in vitro acute alcohol studies. In contrast, monocyte production of the anti-inflammatory cytokine, IL-10, was augmented by acute alcohol intake. Conclusions: Our findings suggest that acute alcohol consumption has dual anti-inflammatory effects that involve augmentation of IL-10 and attenuation of monocyte inflammatory responses involving inhibition of NF- ,B. These mechanisms may contribute to the beneficial effects of moderate alcohol use on atherosclerosis. [source] 6-Shogaol suppressed lipopolysaccharide-induced up-expression of iNOS and COX-2 in murine macrophagesMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 12 2008Min-Hsiung Pan Abstract Ginger, the rhizome of Zingiber officinale, is a traditional medicine with carminative effect, antinausea, anti-inflammatory, and anticarcinogenic properties. In this study, we investigated the inhibitory effects of 6-shogaol and a related compound, 6-gingerol, on the induction of nitric oxide synthase (NOS) and cyclooxygenase-2 (COX-2) in murine RAW 264.7 cells activated with LPS. Western blotting and reverse transcription-PCR analyses demonstrated that 6-shogaol significantly blocked protein and mRNA expression of inducible NOS (iNOS) and COX-2 in LPS-induced macrophages. The in vivo anti-inflammatory activity was evaluated by a topical 12- O -tetradecanoylphorbol 13-acetate (TPA) application to mouse skin. When applied topically onto the shaven backs of mice prior to TPA, 6-shogaol markedly inhibited the expression of iNOS and COX-2 proteins. Treatment with 6-shogaol resulted in the reduction of LPS-induced nuclear translocation of nuclear factor-,B (NF,B) subunit and the dependent transcriptional activity of NF,B by blocking phosphorylation of inhibitor ,B (I,B), and p65 and subsequent degradation of I,B,. Transient transfection experiments using NF,B reporter constructs indicated that 6-shogaol inhibits the transcriptional activity of NF,B in LPS-stimulated mouse macrophages. We found that 6-shogaol also inhibited LPS-induced activation of PI3K/Akt and extracellular signal-regulated kinase 1/2, but not p38 mitogen-activated protein kinase (MAPK). Taken together, these results show that 6-shogaol downregulates inflammatory iNOS and COX-2 gene expression in macrophages by inhibiting the activation of NF,B by interfering with the activation PI3K/Akt/I,B kinases IKK and MAPK. [source] Exacerbating mechanisms mediated by LPS-induced activation of coagulation system in IgA nephropathy model mouse HIGANEPHROLOGY, Issue 2006MAKIKO SHIMOSAWA [source] Inhibition of LPS-induced chemokine production in human lung endothelial cells by lipid conjugates anchored to the membraneBRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2002G Ch Beck In acute respiratory distress syndrome (ARDS) induced by endotoxins, a high production of inflammatory mediators by microvascular lung endothelial cells (LMVEC) can be observed. Activation of cells by endotoxins may result in elevated secretion of phospholipase A2 (sPLA2) which is thought to contribute to tissue damage. The present study was undertaken to investigate the role of sPLA2 in chemokine production in human lung microvascular endothelial cells (LMVEC) stimulated with the endotoxins lipopolysaccharide (LPS) and lipoteichoic acid (LTA). In particular, we investigated the effects of sPLA2 inhibitors, specifically, the extracellular PLA2 inhibitors (ExPLIs), composed of N-derivatized phosphatidyl-ethanolamine linked to polymeric carriers, and LY311727, a specific inhibitor of non-pancreatic sPLA2. ExPLIs markedly inhibited LPS and LTA induced production and mRNA expression of the neutrophile attracting chemokines IL-8, Gro-, and ENA-78, as well as of the adhesion molecules ICAM-1 and E-selectin. Concomitantly, ExPLIs inhibited the LPS-induced activation of NF-,B by LPS but not its activation by TNF-, or IL-1. Endotoxin mediated chemokine production in LMVEC seems not to involve PLA2 activity, since LPS stimulation was not associated with activation of intracellular or secreted PLA2. It therefore seems that the inhibitory effect of the ExPLIs was not due to their PLA2 inhibiting capacity. This was supported by the finding that the LPS-induced chemokine production was not affected by the selective sPLA2 inhibitor LY311727. It is proposed that the ExPLIs may be considered a prototype of potent suppressors of specific endotoxin-induced inflammatory responses, with potential implications for the therapy of subsequent severe inflammation. British Journal of Pharmacology (2002) 135, 1665,1674; doi:10.1038/sj.bjp.0704618 [source] | |||||||||||||