GSE126204
Nitro-fatty acids protect against steatosis and fibrosis during development of nonalcoholic fatty liver disease in mice
Lack of non-invasive diagnostic tools and effective therapies constitute two of the major hurdles for a bona fide treatment against non-alcoholic steatohepatitis (NASH) progression and/or regression of nonalcoholic fatty liver disease (NAFLD). Nitro-oleic acid (OA-NO2) has been proven effective in multiple experimental models of inflammation and fibrosis. Thus, the potential benefit of in vivo administration of OA-NO2 to treat advanced NAFLD was studied in a model of long-term NASH diet-induced liver damage. Non-invasive imaging (e.g. photoacustic-ultrasound (PA-US)) was pursued to establish advanced experimental NASH in mice in which both steatosis and fibrosis were diagnosed prior experimental OA-NO2 therapy. CLAMS and NMR-based analysis demonstrates that OA-NO2 improves body composition and energy metabolism and inhibits hepatic triglyceride accumulation. PA-US imaging revealed a robust inhibition of liver steatosis and fibrosis by OA-NO2. RNA-sequencing analysis uncovered inflammation and fibrosis as major pathways suppressed by OA-NO2 administration, as well as regulation of lipogenesis and lipolysis pathways, with a robust inhibition of SREBP1-dependent lipogenic gene expression by OA-NO2. Global liver transcriptome in response to OA-NO2 was confirmed in vivo and in isolated hepatocytes. These results were further supported by histological analysis and quantification of lipid accumulation, lobular inflammation (F4/80 staining) and fibrosis (collagen deposition, aSMA staining) as well as established parameters of liver damage (ALT). In vitro studies indicate that OA-NO2 inhibits TG biosynthesis and accumulation in hepatocytes and inhibits fibrogenesis in human stellate cells. Taken together, OA-NO2 improve steatohepatitis and fibrosis and may constitute an effective therapeutic approach against advanced NAFLD that warrants further clinical evaluation. Overall design: C57BL/6J mice were fed standard chow diet (CD) or NASH-diet rich in saturated fat, trans-fat, fructose and cholesterol (40% of calories from fat, Research Diets D17010103) for 24 weeks. All mice were maintained on a 12-hour light/dark cycle and had ad libitum access to food and water. Mice were subjected to subcutaneous implantation of osmotic minipumps for delivery of polyethylenglycol (PEG), PEG-solvated oleic acid (OA),  or PEG-solvated OA-NO2 at an infusion rate of 5 mg/kg/day.