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Knockdown of ezrin causes intrahepatic cholestasis by the dysregulation of bile fluidity in the bile duct epithelium in mice
Author(s) -
Hatano Ryo,
Akiyama Kaori,
Tamura Atsushi,
Hosogi Shigekuni,
Marunaka Yoshinori,
Caplan Michael J.,
Ueno Yoshiyuki,
Tsukita Sachiko,
Asano Shinji
Publication year - 2015
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.27565
Subject(s) - ezrin , cholestasis , cystic fibrosis transmembrane conductance regulator , intrahepatic bile ducts , bile duct , progressive familial intrahepatic cholestasis , apical membrane , gene knockdown , radixin , medicine , cholangiocyte , biology , bile acid , endocrinology , pathology , chemistry , epithelium , cystic fibrosis , cytoskeleton , cell , biochemistry , apoptosis , transplantation , liver transplantation
Cholangiopathies share common features, including bile duct proliferation, periportal fibrosis, and intrahepatic cholestasis. Damage of biliary epithelium by autoimunne disorder, virus infection, toxic compounds, and developmental abnormalities causes severe progressive hepatic disorders responsible for high mortality. However, the etiologies of these cholestatic diseases remain unclear because useful models to study the pathogenic mechanisms are not available. In the present study, we have found that ezrin knockdown ( Vil2 kd/kd ) mice develop severe intrahepatic cholestasis characterized by extensive bile duct proliferation, periductular fibrosis, and intrahepatic bile acid accumulation without developmental defects of bile duct morphology and infiltration of inflammatory cells. Ezrin is a membrane cytoskeletal cross‐linker protein, which is known to interact with transporters, scaffold proteins, and actin cytoskeleton at the plasma membrane. We found that the normal apical membrane localizations of several transport proteins including cystic fibrosis transmembrane conductance regulator (CFTR), anion exchanger 2 (AE‐2), aquaporin 1 (AQP1), and Na + /H + exchanger regulatory factor were disturbed in bile ducts of Vil2 kd/kd mice. Stable expression of a dominant negative form of ezrin in immortalized mouse cholangiocytes also led to the reduction of the surface expression of CFTR, AE‐2, and AQP1. Reduced surface expression of these transport proteins was accompanied by reduced functional expression, as evidenced by the fact these cells exhibited decreased CFTR‐mediated Cl − efflux activity. Furthermore, bile flow and biliary HCO 3 − concentration were also significantly reduced in Vil2 kd/kd mice. Conclusion : Dysfunction of ezrin mimics important aspects of the pathological mechanisms responsible for cholangiopathies. The Vil2 kd/kd mouse may be a useful model to exploit in the development and testing of potential therapies for cholangiopathies. (H epatology 2015;61:1660‐1671)