title: TRAIL regulates collagen production through HSF1-dependent Hsp47 expression in activated hepatic stellate cells.
abstract: Hsp47 is a collagen-specific molecular chaperone, whose activity has been implicated in liver fibrosis. In this study, we showed that TRAIL treatment inhibited Hsp47 expression in dose- and time-dependent manners, subsequently leading to the decrease of collagen production in activated human hepatic stellate LX-2 cells. Overexpression of Hsp47 in LX-2 cells acquired resistance for TRAIL-induced collagen reduction and conversely, siRNA suppression of Hsp47 enhanced the decrease of collagen production due to TRAIL treatment. Moreover, we found that Hsp47 expression was under the transcriptional control of heat shock factor (HSF) 1 which is highly located on nucleus in activated human hepatic stellate LX-2 cells. Treatment of LX-2 cells with TRAIL decreased the active trimer formation of HSF1, increased the dephosphorylation of HSF1 (Ser(230)), and enhanced the translocation of HSF1 into cytosol. The accumulated HSF1 in cytosol led to downregulation of Hsp47 expression, resulting in the reduction of collagen production. Consistently, HSF1 silencing by siRNA prevented Hsp47 induction and subsequent collagen production, whereas overexpression of HSF1 restored the expression level of Hsp47 as well as collagen production in response to TRAIL treatment in LX-2 cells. Taken together, our data suggested that TRAIL induced HSF1 inactivation, consequently leading to the suppression of Hsp47-dependent collagen production in activated human hepatic stellate cells. Therefore, this study suggests that TRAIL may be an effective strategy for antifibrotic therapy in liver fibrosis.
authors.affiliation: Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do 363-951, Korea.
authors.forename: Soo-Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Hee-Young
authors.initials: HY
authors.lastname: Sohn
authors.forename: Sang Ick
authors.initials: SI
authors.lastname: Park
mesh_terms: D002460:Cell Line; D003094:Collagen / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015536:Down-Regulation; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D050958:HSP47 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000076249:Heat Shock Transcription Factors; D055166:Hepatic Stellate Cells / Q000378:metabolism*; D006801:Humans; D008103:Liver Cirrhosis / Q000188:drug therapy / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology* / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D050958:HSP47 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; D034741:RNA, Small Interfering; C494660:SERPINH1 protein, human; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014157:Transcription Factors; D003094:Collagen