Eupatilin attenuates bile acid-induced hepatocyte apoptosis.
BACKGROUND
In cases of cholestasis, bile acids induce hepatocyte apoptosis by activating death receptor-mediated apoptotic signaling cascades. Eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) is a pharmacologically active ingredient found in Artemisia asiatica and exhibits cytoprotective effects against experimentally induced gastrointestinal, pancreatic, and hepatic damage. This study was undertaken to examine if eupatilin modulates bile acid-induced hepatocyte apoptosis.


METHODS
Huh-BAT cells, a human hepatocellular carcinoma cell line stably transfected with a bile acid transporter, were used in this study. Apoptosis was quantified using 4',6-diamidino-2-phenylindole dihydrochloride staining, and its signaling cascades were explored by immunoblot analysis. Kinase signaling was evaluated by immunoblotting and by using selective inhibitors. Eupatilin's in vivo effect on bile acid-induced hepatocyte apoptosis was explored in bile duct-ligated rats.


RESULTS
Eupatilin significantly reduced bile acid-mediated hepatocyte apoptosis by attenuating bile acid-induced caspase 8 cleavage. Eupatilin diminished the bile acid-induced activation of mitogen-activated protein kinases, including p38 mitogen-activated protein kinase and c-Jun N-terminal kinase. In particular, the eupatilin-mediated inhibition of bile acid-induced c-Jun N-terminal kinase activation was found to be responsible for attenuating caspase 8 cleavage. Moreover, eupatilin diminished hepatocyte apoptosis in bile duct-ligated rats.


CONCLUSIONS
Eupatilin attenuates bile acid-induced hepatocyte apoptosis by suppressing bile acid-induced kinase activation. Therefore, eupatilin might be therapeutically efficacious in a variety of human liver diseases associated with cholestasis.
Park
Su Cheol
SC
Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, 28 Yungun-dong Chongno-gu, Seoul 110-744, Republic of Korea.
Yoon
Jung-Hwan
JH
Kim
Won
W
Gwak
Geum-Youn
GY
Kim
Kang Mo
KM
Lee
Sung-Hee
SH
Lee
Soo-Mi
SM
Lee
Hyo-Suk
HS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053181:Caspase 8 / Q000378:metabolism; D045744:Cell Line, Tumor; D002779:Cholestasis / Q000188:drug therapy; D003840:Deoxycholic Acid / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology*; D022781:Hepatocytes / Q000187:drug effects*; D006801:Humans; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008297:Male; D008856:Microscopy, Fluorescence; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D005419:Flavonoids; D003840:Deoxycholic Acid; C045325:eupatilin; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D053181:Caspase 8