Ethanol and arachidonic acid increase α2(I) collagen expression in rat hepatic stellate cells overexpressing cytochrome P450 2E1: Role of H2O2 and cyclooxygenase-2

Natalia Nieto, Patricia Greenwel, Scott L. Friedman, Fan Zhang, Andrew J. Dannenberg, Arthur I. Cederbaum

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    113 Scopus citations

    Abstract

    The ability of ethanol and arachidonic acid (AA), as inducers of oxidative stress and key factors in alcoholic liver disease, to up-regulate alpha 2 collagen type I (COL1A2) gene expression was studied in a hepatic stellate cell line overexpressing the ethanol-inducible cytochrome P450 2E1 (CYP2E1) (E5 cells). A time- and dose-dependent induction in COL1A2 mRNA by ethanol or AA was observed that was prevented by diallylsulfide, a CYP2E1 inhibitor. Nuclear run-on experiments showed transcriptional activation of the COL1A2 gene by ethanol and AA. Catalase abrogated the increase in COL1A2 mRNA suggesting an H2O2-dependent mechanism. Cyclooxygenase-2 (COX-2) levels and production of prostaglandin E2 upon addition of AA were elevated in the E5 cells. Incubation with NS-398, a COX-2 inhibitor, blocked the effect of AA, but not of ethanol, on COL1A2 expression suggesting that CYP2E1 activates COX-2 expression, and the oxidation of AA by COX-2 is responsible for the increase in COL1A2. Activity of a reporter construct driven by -378 base pairs of the proximal promoter region of the COL1A2 gene increased in E5 but not control cells and was further increased by ethanol or AA. These experiments link CYP2E1-dependent oxidative stress to induction of COX-2 and the actions of ethanol and AA on activation of collagen gene expression in hepatic stellate cells.

    Original languageEnglish (US)
    Pages (from-to)20136-20145
    Number of pages10
    JournalJournal of Biological Chemistry
    Volume275
    Issue number26
    DOIs
    StatePublished - Jun 30 2000

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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