Raquel Fucho1, Laura Martínez1, Anna Baulies1, Sandra Torres1, Nuria Tarrats1, Anna Fernandez1, Vicente Ribas1, Alma M Astudillo2, Jesús Balsinde2, Pablo Garcia-Rovés3, Montserrat Elena4, Ina Bergheim5, Sophie Lotersztajn6, Christian Trautwein7, Hanna Appelqvist8, Adrienne W Paton9, James C Paton9, Mark J Czaja10, Neil Kaplowitz11, Jose C Fernandez-Checa12, Carmen García-Ruiz13. 1. Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain. 2. Institute of Molecular Biology and Genetics CSIC, Medical School, University of Valladolid and CIBERDEM, Valladolid, Spain. 3. Diabetes and Obesity Laboratory, IDIBAPS-Hospital Clinic de Barcelona, Barcelona, Spain. 4. Biochemical Service, Hospital Clinic de Barcelona, Barcelona, Spain. 5. Department of Nutritional Sciences, Friedrich-Schiller-University, Jena, Germany. 6. Université Paris-Est, UMR-S955, UPEC, Créteil, France. 7. Department of Internal Medicine III, University Hospital, RWTH Aachen, Aachen, Germany. 8. Experimental Pathology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden. 9. Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Australia. 10. Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, United States. 11. Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States. 12. Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain; Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States. Electronic address: checa229@yahoo.com. 13. Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain; Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States. Electronic address: cgrbam@iibb.csic.es.
Abstract
BACKGROUND & AIMS: Acid sphingomyelinase (ASMase) is activated in non-alcoholic steatohepatitis (NASH). However, the contribution of ASMase to NASH is poorly understood and limited to hepatic steatosis and glucose metabolism. Here we examined the role of ASMase in high fat diet (HFD)-induced NASH. METHODS: Autophagy, endoplasmic reticulum (ER) stress and lysosomal membrane permeabilization (LMP) were determined in ASMase(-/-) mice fed a HFD. The impact of pharmacological ASMase inhibition on NASH was analyzed in wild type mice fed a HFD. RESULTS: ASMase deficiency determined resistance to hepatic steatosis mediated by a HFD or methionine-choline deficient diet. ASMase(-/-) mice were resistant to HFD-induced hepatic ER stress, but sensitive to tunicamycin-mediated ER stress, indicating selectivity in the resistance of ASMase(-/-) mice to ER stress and steatosis. Autophagic flux, determined in the presence of rapamycin and/or chloroquine, was lower in primary mouse hepatocytes (PMH) from ASMase(-/-) mice and accompanied by increased p62 levels, suggesting autophagic impairment. Moreover, autophagy suppression by chloroquine and brefeldin A caused ER stress in PMH from ASMase(+/+) mice but not in ASMase(-/-) mice. ASMase(-/-) PMH exhibited increased lysosomal cholesterol loading, decreased LMP and apoptosis resistance induced by O-methyl-serine dodecylamide hydrochloride or palmitic acid, effects that were reversed by decreasing cholesterol levels by oxysterol 25-hydroxycholesterol. In vivo pharmacological ASMase inhibition by amitriptyline, a widely used tricyclic antidepressant, protected wild type mice against HFD-induced hepatic steatosis, fibrosis, and liver damage, effects indicative of early-stage NASH. CONCLUSIONS: These findings underscore a critical role for ASMase in diet-induced NASH and suggest the potential of amitriptyline as a treatment for patients with NASH.
BACKGROUND & AIMS:Acid sphingomyelinase (ASMase) is activated in non-alcoholic steatohepatitis (NASH). However, the contribution of ASMase to NASH is poorly understood and limited to hepatic steatosis and glucose metabolism. Here we examined the role of ASMase in high fat diet (HFD)-induced NASH. METHODS: Autophagy, endoplasmic reticulum (ER) stress and lysosomal membrane permeabilization (LMP) were determined in ASMase(-/-) mice fed a HFD. The impact of pharmacological ASMase inhibition on NASH was analyzed in wild type mice fed a HFD. RESULTS:ASMase deficiency determined resistance to hepatic steatosis mediated by a HFD or methionine-choline deficient diet. ASMase(-/-) mice were resistant to HFD-induced hepatic ER stress, but sensitive to tunicamycin-mediated ER stress, indicating selectivity in the resistance of ASMase(-/-) mice to ER stress and steatosis. Autophagic flux, determined in the presence of rapamycin and/or chloroquine, was lower in primary mouse hepatocytes (PMH) from ASMase(-/-) mice and accompanied by increased p62 levels, suggesting autophagic impairment. Moreover, autophagy suppression by chloroquine and brefeldin A caused ER stress in PMH from ASMase(+/+) mice but not in ASMase(-/-) mice. ASMase(-/-) PMH exhibited increased lysosomal cholesterol loading, decreased LMP and apoptosis resistance induced by O-methyl-serine dodecylamide hydrochloride or palmitic acid, effects that were reversed by decreasing cholesterol levels by oxysterol 25-hydroxycholesterol. In vivo pharmacological ASMase inhibition by amitriptyline, a widely used tricyclic antidepressant, protected wild type mice against HFD-induced hepatic steatosis, fibrosis, and liver damage, effects indicative of early-stage NASH. CONCLUSIONS: These findings underscore a critical role for ASMase in diet-induced NASH and suggest the potential of amitriptyline as a treatment for patients with NASH.
Authors: Francisco Caballero; Anna Fernández; Nuria Matías; Laura Martínez; Raquel Fucho; Montserrat Elena; Joan Caballeria; Albert Morales; José C Fernández-Checa; Carmen García-Ruiz Journal: J Biol Chem Date: 2010-04-15 Impact factor: 5.157
Authors: Raquel Ordoñez; Anna Fernández; Néstor Prieto-Domínguez; Laura Martínez; Carmen García-Ruiz; José C Fernández-Checa; José L Mauriz; Javier González-Gallego Journal: J Pineal Res Date: 2015-06-08 Impact factor: 13.007