title: The XBP1 Arm of the Unfolded Protein Response Induces Fibrogenic Activity in Hepatic Stellate Cells Through Autophagy.
abstract: Autophagy and the unfolded protein response (UPR) both promote activation of hepatic stellate cells (HSC), however the link between the two stimuli remains unclear. Here we have explored the role of X-box binding protein 1 (XBP1), one of three UPR effector pathways and sought to establish the interdependence between autophagy and the UPR during HSC activation. XBP1 induction accompanied both culture-based HSC activation and ER stress induced by tunicamycin. Ectopic overexpression of XBP1 induced collagen 1-alpha expression in HSCs, which was inhibited by knockdown of ATG7, a critical autophagy mediator. Genome-wide transcriptomic profiling indicated an upregulation of collagen synthesis pathways, but not of the transforming growth factor (TGF)-b pathway, a canonical fibrogenic driver, suggesting that XBP1 activates a specific subset of fibrogenesis pathways independent of TGF-β1. XBP1 target gene signatures were significantly induced in rodent liver fibrosis models (n = 3-5) and in human samples of non-alcoholic fatty liver disease (NAFLD) (n = 72-135). Thus, XBP1-mediated UPR contributes to fibrogenic HSC activation and is functionally linked to cellular autophagy.
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.
authors.forename: Rosa S
authors.initials: RS
authors.lastname: Kim
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.|Divisions of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kawasaki, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hasegawa
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.|Divisions of Gastroenterology and Hepatology, Geneva University Hospital, Geneva, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Goossens
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.|Research Division, Mitsubishi Tanabe Pharma Corporation, Saitama, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Tsuchida
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.|Institute of Human Development, University of Manchester, United Kingdom.
authors.forename: Varinder
authors.initials: V
authors.lastname: Athwal
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Surgery, Weill Cornell Medical College, New York, US.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Robinson
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Bhattacharya
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.
authors.forename: Hsin-I
authors.initials: HI
authors.lastname: Chou
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.
authors.forename: David Y
authors.initials: DY
authors.lastname: Zhang
authors.affiliation: Division of Surgical Oncology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts, US.
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Fuchs
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.
authors.forename: Youngmin
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.
authors.forename: Yujin
authors.initials: Y
authors.lastname: Hoshida
authors.affiliation: Division of Liver Diseases, Department of Medicine, Liver Cancer Program, Tisch Cancer Institute, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, US.
authors.forename: Scott L
authors.initials: SL
authors.lastname: Friedman
mesh_terms: D000818:Animals; D001343:Autophagy / Q000502:physiology*; D000071193:Autophagy-Related Protein 7 / Q000235:genetics; D002460:Cell Line; D024042:Collagen Type I / Q000096:biosynthesis; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D057809:HEK293 Cells; D055166:Hepatic Stellate Cells / Q000378:metabolism*; D006801:Humans; D008103:Liver Cirrhosis / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D065626:Non-alcoholic Fatty Liver Disease / Q000473:pathology*; D034622:RNA Interference; D034741:RNA, Small Interfering; D014415:Tunicamycin / Q000009:adverse effects; D056811:Unfolded Protein Response / Q000502:physiology*; D000071717:X-Box Binding Protein 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D024042:Collagen Type I; D034741:RNA, Small Interfering; D000071717:X-Box Binding Protein 1; C000605543:XBP1 protein, human; D014415:Tunicamycin; C509349:ATG7 protein, human; D000071193:Autophagy-Related Protein 7