title: Role of the Jak/STAT pathway in the regulation of interleukin-8 transcription by oxidized phospholipids in vitro and in atherosclerosis in vivo.
abstract: Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (Ox-PAPC) and its component phospholipid, 1-palmitoyl-2-epoxyisoprostane-sn-glycero-3-phosphorylcholine, induce endothelial cells (EC) to synthesize chemotactic factors, such as interleukin 8 (IL-8). Previously, we demonstrated a role for c-Src kinase activation in Ox-PAPC-induced IL-8 transcription. In this study, we have examined the mechanism regulating IL-8 transcription by Ox-PAPC downstream of c-Src. Our findings demonstrate an important role for JAK2 in the regulation of IL-8 transcription by Ox-PAPC. Treatment of human aortic EC with Ox-PAPC and 1-palmitoyl-2-epoxyisoprostane-sn-glycero-3-phosphorylcholine induced a rapid yet sustained activation of JAK2; activation of JAK2 by Ox-PAPC was dependent on c-Src kinase activity. Furthermore, pretreatment with selective JAK2 inhibitors significantly reduced Ox-PAPC-induced IL-8 transcription. In previous studies, we also demonstrated activation of STAT3 by Ox-PAPC. Here we provide evidence that STAT3 activation by Ox-PAPC is dependent on JAK2 activation and that STAT3 activation regulates IL-8 transcription by Ox-PAPC in human EC. Transfection with small interfering RNA against STAT3 significantly reduced Ox-PAPC-induced IL-8 transcription. Using chromatin immunoprecipitation assays, we demonstrated binding of activated STAT3 to the sequence flanking the consensus gamma-interferon activation sequence (GAS) in the IL-8 promoter; site-directed mutagenesis of GAS inhibited IL-8 transcription by Ox-PAPC. Finally, these studies demonstrate a role for STAT3 activation in atherosclerosis in vivo. We found increased staining for activated STAT3 in the inflammatory regions of human atherosclerotic lesions and reduced fatty streak formation in EC-specific STAT3 knock-out mice on the atherogenic diet. Taken together, these data demonstrate an important role for the JAK2/STAT3 pathway in Ox-PAPC-induced IL-8 transcription in vitro and in atherosclerosis in vivo.
authors.affiliation: Division of Cardiology, Department of Medicine, Department of Pathology, Molecular Biology Institute, UCLA, Los Angeles, California 90095, USA.
authors.forename: Nima M
authors.initials: NM
authors.lastname: Gharavi
authors.forename: Jackelyn A
authors.initials: JA
authors.lastname: Alva
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Mouillesseaux
authors.forename: Chi
authors.initials: C
authors.lastname: Lai
authors.forename: Michael
authors.initials: M
authors.lastname: Yeh
authors.forename: Winnie
authors.initials: W
authors.lastname: Yeung
authors.forename: Jaclyn
authors.initials: J
authors.lastname: Johnson
authors.forename: Wan Lam
authors.initials: WL
authors.lastname: Szeto
authors.forename: Longsheng
authors.initials: L
authors.lastname: Hong
authors.forename: Michael
authors.initials: M
authors.lastname: Fishbein
authors.forename: Lai
authors.initials: L
authors.lastname: Wei
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Pfeffer
authors.forename: Judith A
authors.initials: JA
authors.lastname: Berliner
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D050197:Atherosclerosis / Q000378:metabolism*; D002196:Capillaries / Q000166:cytology; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology; D004789:Enzyme Activation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D053614:Janus Kinase 2 / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D010084:Oxidation-Reduction; D010713:Phosphatidylcholines / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology; D010766:Phosphorylation; D010957:Plasmids; D034741:RNA, Small Interfering / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
chemical_list: D016209:Interleukin-8; D010713:Phosphatidylcholines; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494087:Stat3 protein, mouse; D015534:Trans-Activators; C472349:oxidized-L-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine; D053614:Janus Kinase 2