Adel Hammoutene1, Louise Biquard2, Juliette Lasselin3, Marouane Kheloufi3, Marion Tanguy1, Anne-Clémence Vion3, Jules Mérian3, Nathalie Colnot4, Xavier Loyer3, Alain Tedgui3, Patrice Codogno5, Sophie Lotersztajn2, Valérie Paradis6, Chantal M Boulanger3, Pierre-Emmanuel Rautou7. 1. Université de Paris, PARCC, INSERM, F-75015, Paris, France; Université de Paris, Centre de recherche sur l'inflammation, Inserm, U1149, CNRS, ERL8252, F-75018, Paris, France. 2. Université de Paris, Centre de recherche sur l'inflammation, Inserm, U1149, CNRS, ERL8252, F-75018, Paris, France. 3. Université de Paris, PARCC, INSERM, F-75015, Paris, France. 4. Service d'Anatomie Pathologique, Hôpital Beaujon, Assistance Publique-Hôpitaux de Paris, Clichy, France. 5. Université de Paris, INEM, INSERM, F-75014, Paris, France; CNRS UMR-8253, 75014, Paris, France. 6. Université de Paris, Centre de recherche sur l'inflammation, Inserm, U1149, CNRS, ERL8252, F-75018, Paris, France; Service d'Anatomie Pathologique, Hôpital Beaujon, Assistance Publique-Hôpitaux de Paris, Clichy, France. 7. Université de Paris, PARCC, INSERM, F-75015, Paris, France; Université de Paris, Centre de recherche sur l'inflammation, Inserm, U1149, CNRS, ERL8252, F-75018, Paris, France; Service d'Hépatologie, DHU Unity, DMU Digest, Hôpital Beaujon, AP-HP, Clichy, France; Centre de Référence des Maladies Vasculaires du Foie, French Network for Rare Liver Diseases (FILFOIE), European Reference Network on Hepatological Diseases (ERN RARE-LIVER). Electronic address: pierre-emmanuel.rautou@inserm.fr.
Abstract
BACKGROUND & AIMS: Previous studies demonstrated that autophagy is protective in hepatocytes and macrophages, but detrimental in hepatic stellate cells in chronic liver diseases. The role of autophagy in liver sinusoidal endothelial cells (LSECs) in non-alcoholic steatohepatitis (NASH) is unknown. Our aim was to analyze the potential implication of autophagy in LSECs in NASH and liver fibrosis. METHODS: We analyzed autophagy in LSECs from patients using transmission electron microscopy. We determined the consequences of a deficiency in autophagy: (a) on LSEC phenotype, using primary LSECs and an LSEC line; (b) on early stages of NASH and on advanced stages of liver fibrosis, using transgenic mice deficient in autophagy specifically in endothelial cells and fed a high-fat diet or chronically treated with carbon tetrachloride, respectively. RESULTS: Patients with NASH had half as many LSECs containing autophagic vacuoles as patients without liver histological abnormalities, or with simple steatosis. LSECs from mice deficient in endothelial autophagy displayed an upregulation of genes implicated in inflammatory pathways. In the LSEC line, deficiency in autophagy enhanced inflammation (Ccl2, Ccl5, Il6 and VCAM-1 expression), features of endothelial-to-mesenchymal transition (α-Sma, Tgfb1, Col1a2 expression) and apoptosis (cleaved caspase-3). In mice fed a high-fat diet, deficiency in endothelial autophagy induced liver expression of inflammatory markers (Ccl2, Ccl5, Cd68, Vcam-1), liver cell apoptosis (cleaved caspase-3) and perisinusoidal fibrosis. Mice deficient in endothelial autophagy treated with carbon tetrachloride also developed more perisinusoidal fibrosis. CONCLUSIONS: A defect in autophagy in LSECs occurs in patients with NASH. Deficiency in endothelial autophagy promotes the development of liver inflammation, features of endothelial-to-mesenchymal transition, apoptosis and liver fibrosis in the early stages of NASH, but also favors more advanced stages of liver fibrosis. LAY SUMMARY: Autophagy is a physiological process controlling endothelial homeostasis in vascular beds outside the liver. This study demonstrates that autophagy is defective in the liver endothelial cells of patients with non-alcoholic steatohepatitis. This defect promotes liver inflammation and fibrosis at early stages of non-alcoholic steatohepatitis, but also at advanced stages of chronic liver disease.
BACKGROUND & AIMS: Previous studies demonstrated that autophagy is protective in hepatocytes and macrophages, but detrimental in hepatic stellate cells in chronic liver diseases. The role of autophagy in liver sinusoidal endothelial cells (LSECs) in non-alcoholic steatohepatitis (NASH) is unknown. Our aim was to analyze the potential implication of autophagy in LSECs in NASH and liver fibrosis. METHODS: We analyzed autophagy in LSECs from patients using transmission electron microscopy. We determined the consequences of a deficiency in autophagy: (a) on LSEC phenotype, using primary LSECs and an LSEC line; (b) on early stages of NASH and on advanced stages of liver fibrosis, using transgenic mice deficient in autophagy specifically in endothelial cells and fed a high-fat diet or chronically treated with carbon tetrachloride, respectively. RESULTS:Patients with NASH had half as many LSECs containing autophagic vacuoles as patients without liver histological abnormalities, or with simple steatosis. LSECs from mice deficient in endothelial autophagy displayed an upregulation of genes implicated in inflammatory pathways. In the LSEC line, deficiency in autophagy enhanced inflammation (Ccl2, Ccl5, Il6 and VCAM-1 expression), features of endothelial-to-mesenchymal transition (α-Sma, Tgfb1, Col1a2 expression) and apoptosis (cleaved caspase-3). In mice fed a high-fat diet, deficiency in endothelial autophagy induced liver expression of inflammatory markers (Ccl2, Ccl5, Cd68, Vcam-1), liver cell apoptosis (cleaved caspase-3) and perisinusoidal fibrosis. Mice deficient in endothelial autophagy treated with carbon tetrachloride also developed more perisinusoidal fibrosis. CONCLUSIONS: A defect in autophagy in LSECs occurs in patients with NASH. Deficiency in endothelial autophagy promotes the development of liver inflammation, features of endothelial-to-mesenchymal transition, apoptosis and liver fibrosis in the early stages of NASH, but also favors more advanced stages of liver fibrosis. LAY SUMMARY: Autophagy is a physiological process controlling endothelial homeostasis in vascular beds outside the liver. This study demonstrates that autophagy is defective in the liver endothelial cells of patients with non-alcoholic steatohepatitis. This defect promotes liver inflammation and fibrosis at early stages of non-alcoholic steatohepatitis, but also at advanced stages of chronic liver disease.
Authors: Markus Ahrens; Ole Ammerpohl; Witigo von Schönfels; Julia Kolarova; Susanne Bens; Timo Itzel; Andreas Teufel; Alexander Herrmann; Mario Brosch; Holger Hinrichsen; Wiebke Erhart; Jan Egberts; Bence Sipos; Stefan Schreiber; Robert Häsler; Felix Stickel; Thomas Becker; Michael Krawczak; Christoph Röcken; Reiner Siebert; Clemens Schafmayer; Jochen Hampe Journal: Cell Metab Date: 2013-08-06 Impact factor: 27.287
Authors: Kunimaro Furuta; Qianqian Guo; Kevin D Pavelko; Jeong-Heon Lee; Keith D Robertson; Yasuhiko Nakao; Jan Melek; Vijay H Shah; Petra Hirsova; Samar H Ibrahim Journal: J Clin Invest Date: 2021-03-15 Impact factor: 14.808
Authors: Daniel J Klionsky; Giulia Petroni; Ravi K Amaravadi; Eric H Baehrecke; Andrea Ballabio; Patricia Boya; José Manuel Bravo-San Pedro; Ken Cadwell; Francesco Cecconi; Augustine M K Choi; Mary E Choi; Charleen T Chu; Patrice Codogno; Maria Isabel Colombo; Ana Maria Cuervo; Vojo Deretic; Ivan Dikic; Zvulun Elazar; Eeva-Liisa Eskelinen; Gian Maria Fimia; David A Gewirtz; Douglas R Green; Malene Hansen; Marja Jäättelä; Terje Johansen; Gábor Juhász; Vassiliki Karantza; Claudine Kraft; Guido Kroemer; Nicholas T Ktistakis; Sharad Kumar; Carlos Lopez-Otin; Kay F Macleod; Frank Madeo; Jennifer Martinez; Alicia Meléndez; Noboru Mizushima; Christian Münz; Josef M Penninger; Rushika M Perera; Mauro Piacentini; Fulvio Reggiori; David C Rubinsztein; Kevin M Ryan; Junichi Sadoshima; Laura Santambrogio; Luca Scorrano; Hans-Uwe Simon; Anna Katharina Simon; Anne Simonsen; Alexandra Stolz; Nektarios Tavernarakis; Sharon A Tooze; Tamotsu Yoshimori; Junying Yuan; Zhenyu Yue; Qing Zhong; Lorenzo Galluzzi; Federico Pietrocola Journal: EMBO J Date: 2021-08-30 Impact factor: 14.012