Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

15-Hydroxyeicosatetraenoic acid [15-(S)-HETE], a major arachidonic acid metabolite produced from the 15-lipoxygenase pathway, has been characterized as an antiinflammatory cellular mediator since it can inhibit the in vivo and in vitro formation of the proinflammatory leukotrienes via the 5-lipoxygenase pathway in various cells. 15-HETE has been confirmed to inhibit the 5-lipoxygenase in rat basophilic leukemia cell (RBL-1) homogenates with an I50 = 7.7 microM. The I50 of the 12-HETE isomer was 6 microM whereas prostaglandin F2 alpha was ineffective. In order to examine the mechanistic basis underlying the inhibitory action of 15-HETE, association assays of [3H]-15-HETE with RBL-1 subcellular fractions were carried out. The presence of the zwitterionic detergent CHAPS enhanced specific [3H]-15-HETE binding in the membrane fractions three-fold and specific 15-HETE binding was distributed among the nuclear (32%)-, granule (19%)-, plasma membrane (35%)-, and cytosol (14%)-enriched fractions. Studies using combined granule and plasma membrane enriched-, CHAPS treated-fractions showed that [3H]-15-HETE binding was time-dependent, specific and reversible, sensitive to pertussis toxin treatment, and indicated a single class of binding sites with a Kd = 460 +/- 160 nM and Bmax = 5.0 +/- 1.1 nM. Competition experiments showed that the order of 15-HETE or analogs in inhibiting the binding of [3H]-15-HETE was: 15(S)-HETE > or = 12-(S)-HETE = 5-(S)-HETE > 15-(R)-HETE > arachidonic acid. Prostaglandin F2 alpha and lipoxin B4 were ineffective as competitors. The similar profiles of the binding assays and inhibition of the 5-lipoxygenase suggest that 15-HETE binding sites may mediate this inhibitory action of 15-HETE.
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PMID:Characterization of specific subcellular 15-hydroxyeicosatetraenoic acid (15-HETE) binding sites on rat basophilic leukemia cells. 778 91

Dual-laser flow cytometry, based on the properties of the DNA-binding dyes Hoechst 33342 and propidium iodide, was used, with light and electron microscopy and DNA fragmentation studies, to define the influence of lipoxygenase-derived eicosanoids on apoptosis of human polymorphonuclear neutrophils (PMN) in vitro. Apoptosis was characterized by progression through an early apoptotic phase characterized by condensation of chromatin and coalescence of nuclear lobes, to a late apoptotic phase characterized by nuclear degradation and evanescence, and secondary necrosis. Prolonged exposure of PMN to leukotriene B4 (LTB4) afforded dose-dependent inhibition of constitutive PMN apoptosis (percentage of normal and apoptotic PMN, respectively, after aging for 18 h: vehicle, 30.5 +/- 2.7% and 61.8 +/- 3.2%; LTB4 10(-7) M, 57.6 +/- 1.2% and 37.6 +/- 1.0%) and apoptosis triggered by the classic peptide chemoattractant FMLP. In contrast, apoptosis was not affected by the LTB4 precursor 5(S)-hydroxyeicosatetraenoic acid (HETE), the omega-oxidation LTB4 metabolites 20-hydroxy-LTB4 and 20-carboxy-LTB4, the cysteinyl leukotriene LTC4, the 15-lipoxygenase product 15(S)-HETE, or the lipoxygenase interaction product lipoxin A4. The anti-apoptotic effect of LTB4 was mimicked by 20,20,20-trifluoro-LTB4, LTB4-dimethylamide, and 14,15-dehydro-LTB4, and was blunted by pertussis toxin and genistein, inhibitors of G alpha i GTP-binding proteins and tyrosine kinases, respectively, but not by staurosporine, 15(S)-HETE, or lipoxin A4. This unique pharmacologic profile suggested that LTB4 attenuated apoptosis through activation of cell surface receptors and signaling events distinct from those involved with PMN trafficking, degranulation, and respiratory bursts.
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PMID:Sequential morphologic events during apoptosis of human neutrophils. Modulation by lipoxygenase-derived eicosanoids. 881 21