Bile acids stimulate cFLIP phosphorylation enhancing TRAIL-mediated apoptosis

Hajime Higuchi, Jung Hwan Yoon, Annette Grambihler, Nathan Werneburg, Steven F. Bronk, Gregory J. Gores

Research output: Contribution to journalArticle

96 Scopus citations

Abstract

Bile acids induce hepatocyte injury by enhancing death receptor-mediated apoptosis. In this study, bile acid effects on TRAIL-mediated apoptosis were examined to gain insight into bile acid potentiation of death receptor signaling. TRAIL-induced apoptosis of HuH-7 cells, stably transfected with a bile acid transporter, was enhanced by bile acids. Caspase 8 and 10 activation, bid cleavage, cytosolic cytochrome c, and caspase 3 activation by TRAIL were all increased by the bile acid glycochenodeoxycholate (GCDCA). GCDCA (100 μM) did not alter expression of TRAIL-R1/DR4, TRAIL-R2/DR5, procaspase 8, cFLIP-L, cFLIP-s, Bax, Bcl-xL, or Bax. However, both caspase 8 and caspase 10 recruitment and processing within the TRAIL death-inducing signaling complex (DISC) were greater in GCDCA-treated cells whereas recruitment of cFLIP long and short was reduced. GCDCA stimulated phosphorylation of both cFLIP isoforms, which was associated with decreased binding to GST-FADD. The protein kinase C antagonist chelerythrine prevented bile acid-stimulated cFLIP-L and -s phosphorylation, restored cFLIP binding to GST-FADD, and attenuated bile acid potentiation of TRAIL-induced apoptosis. These results provide new insights into the mechanisms of bile acid cytotoxicity and the proapoptotic effects of cFLIP phosphorylation in TRAIL signaling.

Original languageEnglish (US)
Pages (from-to)454-461
Number of pages8
JournalJournal of Biological Chemistry
Volume278
Issue number1
DOIs
StatePublished - Jan 3 2003

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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