title: The endocannabinoid 2-arachidonoyl glycerol induces death of hepatic stellate cells via mitochondrial reactive oxygen species.
abstract: The endocannabinoid system is an important regulator of hepatic fibrogenesis. In this study, we determined the effects of 2-arachidonoyl glycerol (2-AG) on hepatic stellate cells (HSCs), the main fibrogenic cell type in the liver. Culture-activated HSCs were highly susceptible to 2-AG-induced cell death with >50% cell death at 10 microM after 18 h of treatment. 2-AG-induced HSC death showed typical features of apoptosis such as PARP- and caspase 3-cleavage and depended on reactive oxygen species (ROS) formation. Confocal microscopy revealed mitochondria as primary site of ROS production and demonstrated mitochondrial depolarization and increased mitochondrial permeability after 2-AG treatment. 2-AG-induced cell death was independent of cannabinoid receptors but required the presence of membrane cholesterol. Primary hepatocytes were resistant to 2-AG-induced ROS induction and cell death but became susceptible after GSH depletion suggesting antioxidant defenses as a critical determinant of 2-AG sensitivity. Hepatic levels of 2-AG were significantly elevated in two models of experimental fibrogenesis and reached concentrations that are sufficient to induce death in HSCs. These findings suggest that 2-AG may act as an antifibrogenic mediator in the liver by inducing cell death in activated HSCs but not hepatocytes.
authors: Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, New York, USA.
authors: Sören V
authors: SV
authors: Siegmund
authors: Ting
authors: T
authors: Qian
authors: Samuele
authors: S
authors: de Minicis
authors: Judith
authors: J
authors: Harvey-White
authors: George
authors: G
authors: Kunos
authors: K Y
authors: KY
authors: Vinod
authors: Basalingappa
authors: B
authors: Hungund
authors: Robert F
authors: RF
authors: Schwabe
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001095:Arachidonic Acids / Q000494:pharmacology*; D015153:Blotting, Western; D063385:Cannabinoid Receptor Modulators / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D063388:Endocannabinoids; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005355:Fibrosis; D005989:Glycerides / Q000494:pharmacology*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000293:injuries / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D043884:Receptor, Cannabinoid, CB1 / Q000235:genetics / Q000502:physiology; D043885:Receptor, Cannabinoid, CB2 / Q000235:genetics / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D005989:Glycerides; D017382:Reactive Oxygen Species; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; C094503:glyceryl 2-arachidonate; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases