Navegando por Palavras-chave "platelet-activating factor"

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    Human neutrophil migration in vitro induced by secretory phospholipases A(2): a role for cell surface glycosaminoglycans
    (Elsevier B.V., 2002-01-01) Gambero, A.; Landucci, ECT; Toyama, M. H.; Marangoni, S.; Giglio, JR; Nader, H. B.; Dietrich, C. P.; De Nucci, G.; Antunes, E.; Universidade Estadual de Campinas (UNICAMP); Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    The purpose of this study was to examine the ability of type I- (porcine pancreas and Naja mocambique mocambique venom), type II- (bothropstoxin-I, bothropstoxin-II, and piratoxin-I). and type III- (Apis mellifera venom) secretory phospholipases A(2) (sPLA(2)s) to induce human neutrophil chemotaxis, and the role of the cell surface proteoglycans, leukotriene B-4 (LTB4), and platelet-activating factor (PAF). in mediating this migration. the neutrophil chemotaxis assays were performed by using a 48-well microchemotaxis chamber. Piratoxin-I, bothropstoxin-I. N. m. mocambique venom PLA(2) (10-1000 mug/mL each), bothropstoxin-II (30-1000 mug/mL), porcine pancreas PLA(2) (0.3-30 mug/mL), and A. mellifera venom PLA(2) (30-300 mug/mL) caused concentration-dependent neutrophil chemotaxis. Heparin (10-300 U/mL) concentration-dependently inhibited the neutrophil migration induced by piratoxin-I, bothropstoxin-II, and N. in. mocambique and A. mellifera venom PLA(2)s (100 mug/mL each), but failed to affect the migration induced by porcine pancreas PLA(2). Heparan sulfate (300 and 1000 mug/mL) inhibited neutrophil migration induced by piratoxin-I, whereas dermatan sulfate and chondroitin sulfate (30-1000 mug/mL each) had no effect. Heparitinase I and heparinase (300 mU/mL each) inhibited by 41.5 and 47%. respectively, piratoxin-l-induced chemotaxis, whereas heparitinase 11 and chondroitinase AC failed to affect the chemotaxis. the PAF receptor antagonist WEB 2086 (3-[4-(2-chlorophenyl)-9-methyl-6H-thienol-[3,2-f] [1,2,4]-triazolo-[4.3-a] [1,4]-diazepine-2-yl]-1-(4-morpholynil)-1-propionate) (0.1-10 muM) and the LTB4 synthesis inhibitor AA-861 [2-(12-hydroxydodeca-5,10-diynyl)-3,5,6-trimethyl-1,4-benzoquinone] (0.1-10 muM) significantly inhibited the piratoxin-I-induced chemotaxis. Piratoxin-I (30-300 mug/mL) caused a concentration-dependent release of LTB4 Our results suggest that neutrophil migration in response to sPLA(2)s is independent of PLA activity, and involves an interaction of sPLA(2)s with cell surface heparin/heparan binding sites triggering the release of LTB4 and PAF. (C) 2002 Elsevier Science Inc. All rights reserved.
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    A Possible role for Platelet-Activating Factor receptor in Amyotrophic Lateral sclerosis treatment
    (Frontiers Media Sa, 2018) Briones, Marcelo R. S. [UNIFESP]; Snyder, Amanda M.; Ferreira, Renata C. [UNIFESP]; Neely, Elizabeth B.; Connor, James R.; Broach, James R.
    Amyotrophic lateral sclerosis (ALS) is the third most prevalent neurodegenerative disease affecting upper and lower motor neurons. An important pathway that may lead to motor neuron degeneration is neuroinflammation. Cerebrospinal Fluids of ALS patients have increased levels of the inflammatory cytokine IL-18. Because IL-18 is produced by dendritic cells stimulated by the platelet-activating factor (PAF), a major neuroinflammatory mediator, it is expected that PAF is involved in ALS. Here we show pilot experimental data on amplification of PAF receptor (PAFR) mRNA by RT-PCR. PAFR is overexpressed, as compared to age matched controls, in the spinal cords of transgenic ALS SOD1-G93A mice, suggesting PAF mediation. Although anti-inflammatory drugs have been tested for ALS before, no clinical trial has been conducted using PAFR specific inhibitors. Therefore, we hypothesize that administration of PAFR inhibitors, such as Ginkgolide B, PCA 4248 and WEB 2086, have potential to function as a novel therapy for ALS, particularly in SOD1 familial ALS forms. Because currently there are only two approved drugs with modest effectiveness for ALS therapy, a search for novel drugs and targets is essential.