Gastroenterology

Gastroenterology

Volume 137, Issue 1, July 2009, Pages 297-308.e4
Gastroenterology

Basic—Liver, Pancreas, and Biliary Tract
c-Met Confers Protection Against Chronic Liver Tissue Damage and Fibrosis Progression After Bile Duct Ligation in Mice

https://doi.org/10.1053/j.gastro.2009.01.068Get rights and content

Background & Aims

The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-Met) system is an essential inducer of hepatocyte growth and proliferation. Although a fundamental role for the HGF receptor c-Met has been shown in acute liver regeneration, its cell-specific role in hepatocytes during chronic liver injury and fibrosis progression has not been determined.

Methods

Hepatocyte-specific c-Met knockout mice (c-MetΔhepa) using the Cre-loxP system were studied in a bile duct ligation (BDL) model. Microarray analyses were performed to define HGF/c-Met–dependent gene expression.

Results

Two strategies for c-Met deletion in hepatocytes to generate hepatocyte-specific c-Met knockout mice were tested. Early deletion during embryonic development was lethal, whereas post-natal Cre expression was successful, leading to the generation of viable c-MetΔhepa mice. BDL in these mice resulted in extensive necrosis and lower proliferation rates of hepatocytes. Gene array analysis of c-MetΔhepa mice revealed a significant reduction of anti-apoptotic genes in c-Met–deleted hepatocytes. These findings could be tested functionally because c-MetΔhepa mice showed a stronger apoptotic response after BDL and Jo-2 stimulation. The phenotype was associated with increased expression of proinflammatory cytokines (tumor necrosis factor-α and interleukin-6) and an enhanced recruitment of neutrophils. Activation of these mechanisms triggered a stronger profibrogenic response as evidenced by increased transforming growth factor-β1, α-smooth muscle actin, collagen-1α messenger RNA expression, and enhanced collagen-fiber staining in c-MetΔhepa mice.

Conclusions

Our results show that deletion of c-Met in hepatocytes leads to more liver cell damage and fibrosis in a chronic cholestatic liver injury model because c-Met triggers survival signals important for hepatocyte recovery.

Section snippets

Generation of Hepatocyte-Specific c-Met Knockout Mice

c-MetloxP/loxP animals11 were first crossed with albumin/α-fetoprotein (AFP) promoter/enhancer12 (Alfp-Cre) or albumin promoter–Cre transgenic animals13 (Alb-Cre). The Alfp-Cre animals express Cre-recombinase during embryonal development, whereas Alb-Cre mice start to express Cre 2 weeks after birth.

BDL

Eight- to 10-week-old mice were subjected to BDL as indicated. BDL was performed by tying the common bile duct using a nonabsorbable filament (Ethicon, Boston, MA). For each of the following

Embryonal Hepatocyte-Specific c-Met Deletion Is Lethal

We first aimed to generate hepatocyte-specific c-Met conditional knockout animals. c-MetloxP/loxP animals were crossed with transgenic animals expressing the Cre-recombinase under the control of an Alfp-Cre construct. Our earlier results showed that this construct results in efficient target gene deletion in hepatocytes at day 12 during embryonic development.14 Interestingly, cross-breeding of c-MetloxP/loxP animals with Alfp-Cre(+/−)/c-MetloxP/wt mice did not result in hepatocyte-specific

Discussion

HGF has been cloned because of its essential role during liver regeneration and has been known for a long time to be strongly involved in liver remodeling and regeneration after hepatic injury. In earlier studies the role of HGF has been investigated by either overexpressing HGF or by deleting its receptor c-Met in whole liver.10, 11, 19 However, only few studies have addressed the role of HGF or c-Met in a specific target cell of the liver (eg, hepatocytes).

HGF and its receptor c-Met have been

References (37)

  • A. Vogel et al.

    Sustained phosphorylation of bid is a marker for resistance to Fas-induced apoptosis during chronic liver diseases

    Gastroenterology

    (2006)
  • L.E. Gomez-Quiroz et al.

    Hepatocyte-specific c-Met deletion disrupts redox homeostasis and sensitizes to Fas-mediated apoptosis

    J Biol Chem

    (2008)
  • F.W. Wolf et al.

    B94, a primary response gene inducible by tumor necrosis factor-alpha, is expressed in developing hematopoietic tissues and the sperm acrosome

    J Biol Chem

    (1994)
  • H. Ikeda et al.

    Activated rat stellate cells express c-met and respond to hepatocyte growth factor to enhance transforming growth factor beta1 expression and DNA synthesis

    Biochem Biophys Res Commun

    (1998)
  • S.L. Friedman et al.

    Hepatic lipocytes: the principal collagen-producing cells of normal rat liver

    Proc Natl Acad Sci U S A

    (1985)
  • Z. Shi et al.

    Strain-specific differences in mouse hepatic wound healing are mediated by divergent T helper cytokine responses

    Proc Natl Acad Sci U S A

    (1997)
  • T. Nakamura et al.

    Molecular cloning and expression of human hepatocyte growth factor

    Nature

    (1989)
  • C. Schmidt et al.

    Scatter factor/hepatocyte growth factor is essential for liver development

    Nature

    (1995)
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    Conflict of interest The authors disclose no conflicts.

    Funding This work was supported by the following grants: DFG STR 661/4-1, START 128/06 (to K.S.); SFB 542, C14, SFB/TRR 57, P04 (to C.T.); and the Netherlands Nutrigenomics Consortium (TI Food & Nutrition) (to M.M.). Microarray data: GEO series accession number: GSE13992.

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