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NADPH Oxidase Activation (nadph + oxidase_activation)
Selected AbstractsButterfat fatty acids differentially regulate growth and differentiation in Jurkat T-cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2005Paolo Bergamo Abstract Synthetic Conjugated Linoleic Acid mixture (CLA; c9,t11; t10,c12-18:2) has been previously shown to inhibit growth, and enhance apoptosis and IL-2 mRNA synthesis in human lymphoblastic Jurkat T-cells. In this study, two different butterfat types were evaluated and compared for their effects on Jurkat cell viability, oxidative stress, pro-apoptotic activity, and cytokine synthesis: the conventionally produced butterfat (CBF), and organic butterfat (OBF) containing significantly higher amounts of c9,t11 (Rumenic Acid, RA), trans-vaccenic acid (VA; t11-18:1), ,-linolenic acid (ALA), and lower levels of linoleic acid (LA). Results from cell treatment with both butterfat mixtures showed comparable oxidative stress (superoxide production, intracellular GSH depletion,and lipid peroxides yield), NADPH oxidase activation, cytotoxicity (LDH release), and IL-2 transcript level, whereas the effects of enhanced growth-inhibitory and pro-apoptotic activities were associated with OBF treatment. To then investigate each butterfat-induced effect caused by RA, VA, LA, and ALA, cells were exposed to synthetic FA concentrations similar to those from the different butterfats. Higher oxidative stress (superoxide production, intracellular GSH depletion) was induced by ,-linolenic (ALA) and linoleic (LA) incubation (P,<,0.01) and superoxide production was suppressed by specific PKC, inhibitor (Gö 6976) and linked to increased toxicity and IL-2 synthesis inhibition. By contrast, cell treatment with RA increased apoptosis and IL-2 synthesis. These results suggest that a supply of ALA and LA is responsible for BF-induced oxidative stress via PKC,-NADPH oxidase pathway, and that enhanced antiproliferative effects in OBF treated cells is essentially determined by RA-induced pro-apoptotic activity. © 2005 Wiley-Liss, Inc. [source] Neuroprotective effects of hydrogen sulfide on Parkinson's disease rat modelsAGING CELL, Issue 2 2010Li-Fang Hu Summary Parkinson's disease (PD) is a neurodegenerative disorder characterized by a progressive loss of dopaminergic neurons in the substantia nigra (SN). The present study was designed to examine the therapeutic effect of hydrogen sulfide (H2S, a novel biological gas) on PD. The endogenous H2S level was markedly reduced in the SN in a 6-hydroxydopamine (6-OHDA)-induced PD rat model. Systemic administration of NaHS (an H2S donor) dramatically reversed the progression of movement dysfunction, loss of tyrosine-hydroxylase positive neurons in the SN and the elevated malondialdehyde level in injured striatum in the 6-OHDA-induced PD model. H2S specifically inhibited 6-OHDA evoked NADPH oxidase activation and oxygen consumption. Similarly, administration of NaHS also prevented the development of PD induced by rotenone. NaHS treatment inhibited microglial activation in the SN and accumulation of pro-inflammatory factors (e.g. TNF-, and nitric oxide) in the striatum via NF-,B pathway. Moreover, significantly less neurotoxicity was found in neurons treated with the conditioned medium from microglia incubated with both NaHS and rotenone compared to that with rotenone only, suggesting that the therapeutic effect of NaHS was, at least partially, secondary to its suppression of microglial activation. In summary, we demonstrate for the first time that H2S may serve as a neuroprotectant to treat and prevent neurotoxin-induced neurodegeneration via multiple mechanisms including anti-oxidative stress, anti-inflammation and metabolic inhibition and therefore has potential therapeutic value for treatment of PD. [source] Effects of lysophospholipids on the generation of reactive oxygen species by fMLP- and PMA-stimulated human neutrophilsLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 3 2002Julia Müller Abstract In this study, the effects of exogenous lysophospholipids,lysophosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine and lysophosphatidylserine,on the kinetics of reactive oxygen species (ROS) production by human neutrophils are described. The ROS production by human neutrophils was monitored by luminol-amplified chemiluminescence after cell stimulation with the chemotactic tripeptide, fMLP, or with the phorbol ester, PMA. The interaction of lysophospholipids with the membrane of human neutrophils was additionally tested by mass spectrometry. Lysophosphatidylcholine showed the most pronounced effect on the chemiluminescence pattern, as well as the intensity of the fMLP and PMA-stimulated cells, whereas lysophosphatidic acid showed a slight priming effect when fMLP was used for stimulation. In the case of fMLP-stimulated cells, lysophosphatidylcholine inhibited the first phase and enhanced the second phase of chemiluminescence, whereas the chemiluminescence of PMA-stimulated neutrophils was inhibited in a concentration-dependent manner. We conclude that lysophosphatidylcholine is able to interact with protein kinase C-dependent signalling pathways leading to NADPH oxidase activation. Copyright © 2002 John Wiley & Sons, Ltd. [source] Cathelicidin LL-37 induces the generation of reactive oxygen species and release of human ,-defensins from neutrophilsBRITISH JOURNAL OF DERMATOLOGY, Issue 6 2007Y. Zheng Summary Background, Psoriasis is characterized by epidermal infiltration of neutrophils that destroy invading microorganisms via a potent antimicrobial arsenal of oxidants and antimicrobial agents. In contrast to atopic dermatitis, psoriasis exhibits low levels of skin infections due to the presence of antimicrobial agents, including cathelicidin LL-37. LL-37 kills a broad spectrum of microbes, and activates neutrophil chemotaxis. Objective, To determine whether or not LL-37 could regulate additional neutrophil functions such as production of cytokines/chemokines, reactive oxygen species and release of neutrophil antimicrobial peptides. Methods, Human peripheral blood neutrophils were used in this study. The production of interleukin (IL)-8 and release of ,-defensins were analysed by enzyme-linked immunosorbent assay, and real-time polymerase chain reaction (PCR) was used to quantify ,-defensin gene expression. Phosphorylation of mitogen-activated protein kinase (MAPK) was determined by Western blotting. The generation of reactive oxygen species was examined using flow cytometry, and intracellular Ca2+ mobilization was measured using a calcium assay kit. Results, LL-37 enhanced the production of IL-8 under the control of MAPK p38 and extracellular signal regulated kinase (ERK), as evidenced by the inhibitory effects of p38 and ERK1/2 inhibitors on LL-37-mediated IL-8 production. Furthermore, LL-37 induced phosphorylation of p38 and ERK. We also revealed that LL-37 stimulated the generation of reactive oxygen species dose- and time-dependently, most probably via NADPH oxidase activation and intracellular Ca2+ mobilization. Finally, LL-37 induced both mRNA expression and protein release of ,-defensins, known as human neutrophil peptide 1,3. Conclusion, Taken together, we suggest that in addition to its microbicidal properties, LL-37 may contribute to innate immunity by enhancing neutrophil host defence functions at inflammation and/or infection sites. [source] Macrophage Stimulating Protein (MSP) evokes superoxide anion production by human macrophages of different originBRITISH JOURNAL OF PHARMACOLOGY, Issue 6 2001Sandra Brunelleschi Macrophage Stimulating Protein (MSP), a serum factor related to Hepatocyte Growth Factor, was originally discovered to stimulate chemotaxis of murine resident peritoneal macrophages. MSP is the ligand for Ron, a member of the Met subfamily of tyrosine kinase receptors. The effects of MSP on human macrophages and the role played in human pathophysiology have long been elusive. We show here that human recombinant MSP (hrMSP) evokes a dose-dependent superoxide anion production in human alveolar and peritoneal macrophages as well as in monocyte-derived macrophages, but not in circulating human monocytes. Consistently, the mature Ron protein is expressed by the MSP responsive cells but not by the unresponsive monocytes. The respiratory burst evoked by hrMSP is quantitatively higher than the one induced by N-formylmethionyl-leucyl-phenylalanine and similar to phorbol myristate acetate-evoked one. To investigate the mechanisms involved in NADPH oxidase activation, leading to superoxide anion production, different signal transduction inhibitors were used. By using the non selective tyrosine kinase inhibitor genistein, the selective c-Src inhibitor PP1, the tyrosine phosphatase inhibitor sodium orthovanadate, the phosphatidylinositol 3-kinase inhibitor wortmannin, the p38 inhibitor SB203580, the MEK inhibitor PD098059, we demonstrate that hrMSP-evoked superoxide production is mediated by tyrosine kinase activity, requires the activation of Src but not of PI 3-kinase. We also show that MAP kinase and p38 signalling pathways are involved. These results clearly indicate that hrMSP induces the respiratory burst in human macrophages but not in monocytes, suggesting for the MSP/Ron complex a role of activator as well as of possible marker for human mature macrophages. British Journal of Pharmacology (2001) 134, 1285,1295; doi:10.1038/sj.bjp.0704356 [source] | |||||||||||||