CCR2 promotes hepatic fibrosis in mice# : Hepatology (original) (raw)

Liver Failure/Cirrhosis/Portal Hypertension

Seki, Ekihiro1*†; de Minicis, Samuele1; Inokuchi, Sayaka1; Taura, Kojiro1; Miyai, Katsumi2; van Rooijen, Nico3; Schwabe, Robert F.4; Brenner, David A.1

1 Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA

2 Department of Pathology, University of California, San Diego, School of Medicine, La Jolla, CA

3 Department of Molecular Cell Biology, Vrije Universiteit Medical Center, Amsterdam, Netherlands

4 Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, NY

* Department of Medicine, University of California, San Diego, School of Medicine, 9500 Gilman Drive MC#0702, Leichatag Biomedical Research Building Room #332MM, La Jolla, CA, 92093-0702

Email:[email protected]

Received July 22, 2008; accepted March 2, 2009.

Published online 16 March 2009 in Wiley InterScience (www.interscience.wiley.com).

Grant sponsor: American Liver Foundation; Grant sponsor: Alimenti e Salute grant from the University of Ancona; Grant sponsor: National Institutes of Health; Grant Number: R01GM041804.

# Potential conflict of interest: Nothing to report.

† fax: 858-822-5370

Additional Supporting Information may be found in the online version of this article.

Abstract

Chemokines and chemokine receptors contribute to the migration of hepatic stellate cells (HSCs) and Kupffer cells, two key cell types in fibrogenesis. Here, we investigate the role of CCR2, the receptor for monocyte chemoattractant protein (MCP)-1, MCP-2, and MCP-3, in hepatic fibrosis. Hepatic CCR2, MCP-1, MCP-2, and MCP-3 messenger RNA expression was increased after bile duct ligation (BDL). Both Kupffer cells and HSCs, but not hepatocytes, expressed CCR2. BDL- and CCl4-induced fibrosis was markedly reduced in CCR2−/− mice as assessed through collagen deposition, α-smooth muscle actin expression, and hepatic hydroxyproline content. We generated CCR2 chimeric mice by the combination of clodronate, irradiation, and bone marrow (BM) transplantation allowing full reconstitution of Kupffer cells, but not HSCs, with BM cells. Chimeric mice containing wild-type BM displayed increased macrophage recruitment, whereas chimeric mice containing CCR2−/− BM showed less macrophage recruitment at 5 days after BDL. Although CCR2 expressed in the BM enhanced macrophage recruitment in early phases of injury, CCR2 expression on resident liver cells including HSCs, but not on the BM, was required for fibrogenic responses in chronic fibrosis models. In vitro experiments demonstrated that HSCs deficient in CCR2−/− or its downstream mediator p47phox−/− did not display extracellular signal-regulated kinase and AKT phosphorylation, chemotaxis, or reactive oxygen species production in response to MCP-1, MCP-2, and MCP-3. Conclusion: Our results indicate that CCR2 promotes HSC chemotaxis and the development of hepatic fibrosis. (Hepatology 2009.)