| 19443073 |
Lafdil F, Chobert MN, Deveaux V, Zafrani ES, Mavier P, Nakano T, Laperche Y, Brouillet A: Growth arrest-specific protein 6 deficiency impairs liver tissue repair after acute toxic hepatitis in mice. J Hepatol. 2009 Jul;51(1):55-66. Epub 2009 Apr 22.
BACKGROUND/AIMS: Resident macrophages and myofibroblasts derived from hepatic stellate cells play a key role in liver wound healing. We previously reported that these sinusoidal cells secrete the growth arrest-specific protein 6 (Gas6) and express Axl, one of its receptors. Here we address the role of Gas6 in the healing process during acute liver injury. METHODS: Toxic hepatitis was induced by a single carbon tetrachloride injection in Gas6 deficient (Gas6 (-/-)) mice and liver recovery was compared with wild-type animals. RESULTS: Gas6 deficiency did not cause any change in CCl (4)-induced liver damage. At 72 h, an efficient tissue repair was observed in wild-type animals whereas in Gas6 (-/-) mice, we noticed a defective wound healing accounted by reduced Kupffer cell activation revealed by a decrease in the induction of CD14, TNF-alpha, IL6 and MCP-1. Gas6-deficiency, by limiting cytokine/chemokine release, prevents hepatocyte proliferation, recruitment of circulating monocytes and accumulation of myofibroblasts in healing areas. We also report a direct chemotactic effect of Gas6 on circulating monocytes which might explain defective macrophage infiltration in liver necrotic areas of Gas6 (-/-) mice. Interestingly in Gas6 (-/-) mice, we observed a high and constitutive expression of Axl and an induction of the suppressor of cytokine signaling SOCS1 after CCl (4) treatment. CONCLUSIONS: The lower level of cytokines/chemokines in Gas6 (-/-) mice after CCl (4) injury, is the consequence of an inhibitory signal arising from Axl receptor overexpression, leading to delayed liver repair in deficient mice. |
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