title: Novel lipid mediator aspirin-triggered lipoxin A4 induces heme oxygenase-1 in endothelial cells.
abstract: Lipoxins (LX) and aspirin-triggered LX (ATL) are eicosanoids generated during inflammation via transcellular biosynthetic routes that elicit distinct anti-inflammatory and proresolution bioactions, including inhibition of leukocyte-mediated injury, stimulation of macrophage clearance of apoptotic neutrophils, repression of proinflammatory cytokine production, and inhibition of cell proliferation and migration. Recently, it was reported that aspirin induces heme oxygenase-1 (HO-1) expression on endothelial cells (EC) in a COX-independent manner, what confers protection against prooxidant insults. However, the underlying mechanisms remain unclear. In this study, we investigated whether an aspirin-triggered lipoxin A(4) stable analog, 15-epi-16-(para-fluoro)-phenoxy-lipoxin A(4) (ATL-1) was able to induce endothelial HO-1. Western blot analysis showed that ATL-1 increased HO-1 protein expression associated with increased mRNA levels on EC in a time- and concentration-dependent fashion. This phenomenon appears to be mediated by the activation of the G protein-coupled LXA(4) receptor because pertussis toxin and Boc-2, a receptor antagonist, significantly inhibited ATL-1-induced HO-1 expression. We demonstrate that treatment of EC with ATL-1 inhibited VCAM and E-selectin expression induced by TNF-alpha or IL-1beta. This inhibitory effect of the analog is modulated by HO-1 because it was blocked by SnPPIX, a competitive inhibitor that blocks HO-1 activity. Our results establish that ATL-1 induces HO-1 in human EC, revealing an undescribed mechanism for the anti-inflammatory activity of these lipid mediators.
authors.affiliation: Departmento de Farmacologia e Psicobiologia, Universidade do Estado do Rio de Janeiro, Brazil.
authors.forename: V
authors.initials: V
authors.lastname: Nascimento-Silva
authors.forename: M A
authors.initials: MA
authors.lastname: Arruda
authors.forename: C
authors.initials: C
authors.lastname: Barja-Fidalgo
authors.forename: C G
authors.initials: CG
authors.lastname: Villela
authors.forename: I M
authors.initials: IM
authors.lastname: Fierro
mesh_terms: D000210:Acute-Phase Reaction / Q000188:drug therapy / Q000378:metabolism; D001241:Aspirin / Q000494:pharmacology*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D019040:E-Selectin / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000276:immunology; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006801:Humans; D044045:Lipoxins / Q000378:metabolism / Q000494:pharmacology*; D008565:Membrane Proteins; D009842:Oligopeptides / Q000494:pharmacology; D037342:Pertussis Toxin / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014471:Umbilical Veins / Q000166:cytology; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
chemical_list: C447621:16-(4-fluorophenoxy)lipoxin A4; D016861:Cyclooxygenase Inhibitors; D019040:E-Selectin; D044045:Lipoxins; D008565:Membrane Proteins; D009842:Oligopeptides; D012333:RNA, Messenger; D019010:Vascular Cell Adhesion Molecule-1; C040527:lipoxin A4; C033373:butyloxycarbonyl-phenylalanyl-leucyl-phenylalanyl-leucyl-phenylalanine; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D037342:Pertussis Toxin; D001241:Aspirin