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Hepatic stellate cells express functional CXCR4: Role in stromal cell–derived factor‐1α–mediated stellate cell activation
Author(s) -
Hong Feng,
Tuyama Ana,
Lee Ting Fang,
Loke Johnny,
Agarwal Ritu,
Cheng Xin,
Garg Anita,
Fiel M. Isabel,
Schwartz Myron,
Walewski Jose,
Branch Andrea,
Schecter Alison D.,
Bansal Meena B.
Publication year - 2009
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.22890
Subject(s) - hepatic stellate cell , microbiology and biotechnology , stromal cell , cxc chemokine receptors , biology , protein kinase b , stromal cell derived factor 1 , signal transduction , cancer research , chemokine receptor , receptor , cxcr4 , chemokine , endocrinology , biochemistry
Abstract Chemokine interactions with their receptors have been implicated in hepatic stellate cell (HSC) activation. The hepatic expression of CXCR4 messenger RNA is increased in hepatitis C cirrhotic livers and plasma levels of its endogenous ligand, stromal cell–derived factor‐1α (SDF‐1α), correlate with increased fibrosis in these patients. The expression of CXCR4 by HSCs has not been reported. We therefore examined whether HSCs express CXCR4 in vivo and in vitro and explored whether SDF‐1α/CXCR4 receptor engagement promotes HSC activation, fibrogenesis, and proliferation. The hepatic protein expression of both CXCR4 and SDF‐1α is increased in hepatitis C cirrhotic livers and immunoflourescent and immunohistochemical staining confirms that HSCs express CXCR4 in vivo. Immortalized human stellate cells as well as primary human HSCs express CXCR4, and cell surface receptor expression increases with progressive culture‐induced activation. Treatment of stellate cells with recombinant SDF‐1α increases expression of α‐smooth muscle actin and collagen I and stimulates a dose‐dependent increase in HSC proliferation. Inhibitor studies suggest that SDF‐1α/CXCR4‐dependent extracellular signal‐regulated kinase 1/2 and Akt phosphorylation mediate effects on collagen I expression and stellate cell proliferation. Conclusion: HSCs express CXCR4 receptor in vivo and in vitro. CXCR4 receptor activation by SDF‐1α is profibrogenic through its effects on HSC activation, fibrogenesis, and proliferation. Extracellular signal‐regulated kinase 1/2 and phosphoinositide 3‐kinase pathways mediate SDF‐1α–induced effects on HSC expression of collagen I and proliferation. The availability of small molecule inhibitors of CXCR4 make this receptor an appealing target for antifibrotic approaches. (H EPATOLOGY 2009.)