Amine Majdi1, Lynda Aoudjehane1, Vlad Ratziu2, Tawhidul Islam3, Marta B Afonso4, Filomena Conti5, Taïeb Mestiri1, Marie Lagouge6, Fabienne Foufelle6, Florine Ballenghien1, Tatiana Ledent7, Marthe Moldes1, Axelle Cadoret1, Laura Fouassier1, Jean-Louis Delaunay1, Tounsia Aït-Slimane1, Gilles Courtois8, Bruno Fève9, Olivier Scatton10, Carina Prip-Buus11, Cecília M P Rodrigues4, Chantal Housset12, Jérémie Gautheron13. 1. Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine (CRSA), Paris, France; Institute of Cardiometabolism and Nutrition (ICAN), Paris, France. 2. Institute of Cardiometabolism and Nutrition (ICAN), Paris, France; Assistance Publique-Hôpitaux de Paris (AP-HP), Pitié-Salpêtrière Hospital, Department of Hepatology, Paris, France; Sorbonne Université, Inserm, Centre de Recherche des Cordeliers (CRC), Paris, France. 3. Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal; Université Paris Descartes, Institut Cochin, Inserm, CNRS, Paris, France. 4. Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal. 5. Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine (CRSA), Paris, France; Institute of Cardiometabolism and Nutrition (ICAN), Paris, France; AP-HP, Pitié-Salpêtrière Hospital, Department of Medical Liver Transplantation, Paris, France. 6. Institute of Cardiometabolism and Nutrition (ICAN), Paris, France; Sorbonne Université, Inserm, Centre de Recherche des Cordeliers (CRC), Paris, France. 7. Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine (CRSA), Paris, France. 8. Inserm, CEA, Institut de Biosciences et Biotechnologies (BIG), Grenoble, France. 9. Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine (CRSA), Paris, France; Institute of Cardiometabolism and Nutrition (ICAN), Paris, France; AP-HP, Saint-Antoine Hospital, Department of Endocrinology, Paris, France. 10. Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine (CRSA), Paris, France; AP-HP, Pitié-Salpêtrière Hospital, Department of Hepatobiliary Surgery and Liver Transplantation, Paris, France. 11. Université Paris Descartes, Institut Cochin, Inserm, CNRS, Paris, France. 12. Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine (CRSA), Paris, France; Institute of Cardiometabolism and Nutrition (ICAN), Paris, France; AP-HP, Saint-Antoine Hospital, Department of Hepatology, Paris, France. 13. Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine (CRSA), Paris, France; Institute of Cardiometabolism and Nutrition (ICAN), Paris, France. Electronic address: jeremie.gautheron@inserm.fr.
Abstract
BACKGROUND & AIMS: In non-alcoholic fatty liver disease (NAFLD), hepatocytes can undergo necroptosis: a regulated form of necrotic cell death mediated by the receptor-interacting protein kinase (RIPK) 1. Herein, we assessed the potential for RIPK1 and its downstream effector mixed lineage kinase domain-like protein (MLKL) to act as therapeutic targets and markers of activity in NAFLD. METHODS: C57/BL6J-mice were fed a normal chow diet or a high-fat diet (HFD). The effect of RIPA-56, a highly specific inhibitor of RIPK1, was evaluated in HFD-fed mice and in primary human steatotic hepatocytes. RIPK1 and MLKL concentrations were measured in the serum of patients with NAFLD. RESULTS: When used as either a prophylactic or curative treatment for HFD-fed mice, RIPA-56 caused a downregulation of MLKL and a reduction of liver injury, inflammation and fibrosis, characteristic of non-alcoholic steatohepatitis (NASH), as well as of steatosis. This latter effect was reproduced by treating primary human steatotic hepatocytes with RIPA-56 or necrosulfonamide, a specific inhibitor of human MLKL, and by knockout (KO) of Mlkl in fat-loaded AML-12 mouse hepatocytes. Mlkl-KO led to activation of mitochondrial respiration and an increase in β-oxidation in steatotic hepatocytes. Along with decreased MLKL activation, Ripk3-KO mice exhibited increased activities of the liver mitochondrial respiratory chain complexes in experimental NASH. In patients with NAFLD, serum concentrations of RIPK1 and MLKL increased in correlation with activity. CONCLUSION: The inhibition of RIPK1 improves NASH features in HFD-fed mice and reverses steatosis via an MLKL-dependent mechanism that, at least partly, involves an increase in mitochondrial respiration. RIPK1 and MLKL are potential serum markers of activity and promising therapeutic targets in NAFLD. LAY SUMMARY: There are currently no pharmacological treatment options for non-alcoholic fatty liver disease (NAFLD), which is now the most frequent liver disease. Necroptosis is a regulated process of cell death that can occur in hepatocytes during NAFLD. Herein, we show that RIPK1, a gatekeeper of the necroptosis pathway that is activated in NAFLD, can be inhibited by RIPA-56 to reduce not only liver injury, inflammation and fibrosis, but also steatosis in experimental models. These results highlight the potential of RIPK1 as a therapeutic target in NAFLD.
BACKGROUND & AIMS: In non-alcoholic fatty liver disease (NAFLD), hepatocytes can undergo necroptosis: a regulated form of necrotic cell death mediated by the receptor-interacting protein kinase (RIPK) 1. Herein, we assessed the potential for RIPK1 and its downstream effector mixed lineage kinase domain-like protein (MLKL) to act as therapeutic targets and markers of activity in NAFLD. METHODS: C57/BL6J-mice were fed a normal chow diet or a high-fat diet (HFD). The effect of RIPA-56, a highly specific inhibitor of RIPK1, was evaluated in HFD-fed mice and in primary human steatotic hepatocytes. RIPK1 and MLKL concentrations were measured in the serum of patients with NAFLD. RESULTS: When used as either a prophylactic or curative treatment for HFD-fed mice, RIPA-56 caused a downregulation of MLKL and a reduction of liver injury, inflammation and fibrosis, characteristic of non-alcoholic steatohepatitis (NASH), as well as of steatosis. This latter effect was reproduced by treating primary human steatotic hepatocytes with RIPA-56 or necrosulfonamide, a specific inhibitor of humanMLKL, and by knockout (KO) of Mlkl in fat-loaded AML-12 mouse hepatocytes. Mlkl-KO led to activation of mitochondrial respiration and an increase in β-oxidation in steatotic hepatocytes. Along with decreased MLKL activation, Ripk3-KO mice exhibited increased activities of the liver mitochondrial respiratory chain complexes in experimental NASH. In patients with NAFLD, serum concentrations of RIPK1 and MLKL increased in correlation with activity. CONCLUSION: The inhibition of RIPK1 improves NASH features in HFD-fed mice and reverses steatosis via an MLKL-dependent mechanism that, at least partly, involves an increase in mitochondrial respiration. RIPK1 and MLKL are potential serum markers of activity and promising therapeutic targets in NAFLD. LAY SUMMARY: There are currently no pharmacological treatment options for non-alcoholic fatty liver disease (NAFLD), which is now the most frequent liver disease. Necroptosis is a regulated process of cell death that can occur in hepatocytes during NAFLD. Herein, we show that RIPK1, a gatekeeper of the necroptosis pathway that is activated in NAFLD, can be inhibited by RIPA-56 to reduce not only liver injury, inflammation and fibrosis, but also steatosis in experimental models. These results highlight the potential of RIPK1 as a therapeutic target in NAFLD.
Authors: Yu Lan; Ping Bai; Yan Liu; Sepideh Afshar; Robin Striar; Anna Kathryn Rattray; Tyler Nicholas Meyer; Amelia G Langan; Alisa M Posner; Shiqian Shen; Rudolph E Tanzi; Can Zhang; Changning Wang Journal: J Med Chem Date: 2021-10-15 Impact factor: 8.039
Authors: Sabira Mohammed; Evan H Nicklas; Nidheesh Thadathil; Ramasamy Selvarani; Gordon H Royce; Michael Kinter; Arlan Richardson; Sathyaseelan S Deepa Journal: Free Radic Biol Med Date: 2021-01-09 Impact factor: 7.376