title: Mechanisms of Hypoxic Up-Regulation of Versican Gene Expression in Macrophages.
abstract: Hypoxia is a hallmark of many pathological tissues. Macrophages accumulate in hypoxic sites and up-regulate a range of hypoxia-inducible genes. The matrix proteoglycan versican has been identified as one such gene, but the mechanisms responsible for hypoxic induction are not fully characterised. Here we investigate the up-regulation of versican by hypoxia in primary human monocyte-derived macrophages (HMDM), and, intriguingly, show that versican mRNA is up-regulated much more highly (>600 fold) by long term hypoxia (5 days) than by 1 day of hypoxia (48 fold). We report that versican mRNA decay rates are not affected by hypoxia, demonstrating that hypoxic induction of versican mRNA is mediated by increased transcription. Deletion analysis of the promoter identified two regions required for high level promoter activity of luciferase reporter constructs in human macrophages. The hypoxia-inducible transcription factor HIF-1 has previously been implicated as a key potential regulator of versican expression in hypoxia, however our data suggest that HIF-1 up-regulation is unlikely to be principally responsible for the high levels of induction observed in HMDM. Treatment of HMDM with two distinct specific inhibitors of Phosphoinositide 3-kinase (PI3K), LY290042 and wortmannin, significantly reduced induction of versican mRNA by hypoxia and provides evidence of a role for PI3K in hypoxic up-regulation of versican expression.
authors.affiliation: Department of Biology, School of Basic Science, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Fattah
authors.initials: F
authors.lastname: Sotoodehnejadnematalahi
authors.affiliation: Clinical & Experimental Sciences, University of Southampton Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Staples
authors.affiliation: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom.
authors.forename: Elvina
authors.initials: E
authors.lastname: Chrysanthou
authors.affiliation: Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom.
authors.forename: Helen
authors.initials: H
authors.lastname: Pearson
authors.affiliation: EvA Study Center, Asklepios Fachkliniken and Helmholtz-Zentrum Muenchen, Gauting, Germany.
authors.forename: Loems
authors.initials: L
authors.lastname: Ziegler-Heitbrock
authors.affiliation: Dental School, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Bernard
authors.initials: B
authors.lastname: Burke
mesh_terms: D001483:Base Sequence; D015687:Cell Hypoxia / Q000235:genetics; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D015151:Immunoblotting; D008156:Luciferases / Q000378:metabolism; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D020871:RNA Stability / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015854:Up-Regulation / Q000235:genetics*; D053675:Versicans / Q000235:genetics* / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D051176:beta Catenin; D053675:Versicans; D008156:Luciferases; D019869:Phosphatidylinositol 3-Kinases