Nitro-fatty acids protect against steatosis and fibrosis during development of nonalcoholic fatty liver disease in mice

Abstract

Background Nonalcoholic fatty liver disease (NAFLD) and resulting nonalcoholic steatohepatitis (NASH) are reaching global epidemic proportions. Lack of non-invasive diagnostic tools and effective therapies constitute two of the major hurdles for a bona fide treatment and a reversal of NASH progression and/or regression of the disease. Nitro-oleic acid (OA-NO 2 ) has been proven effective in multiple experimental models of inflammation and fibrosis. Thus, the potential benefit of in vivo administration of OA-NO 2 to treat advanced NAFLD was tested herein in a model of long-term NASH diet-induced liver damage. Methods Non-invasive imaging (e.g. photoacustic-ultrasound (PA-US)) was pursued to establish advanced experimental model of NASH in mice in which both steatosis and fibrosis were diagnosed prior experimental therapy with OA-NO 2 . Experimental controls included equimolar amounts of the non-nitrated oleic acid (OA). CLAMS and NMR-based analysis was used for energy metabolism. Findings CLAMS and NMR-based analysis demonstrates that OA-NO 2 improves body composition and energy metabolism and inhibits hepatic triglyceride (TG) accumulation. Photoacoustic-ultrasound imaging revealed a robust inhibition of liver steatosis and fibrosis by OA-NO 2 . RNA-sequencing analysis uncovered inflammation and fibrosis as major pathways suppressed by OA-NO 2 administration, as well as regulation of lipogenesis and lipolysis pathways, with a robust inhibition of SREBP1 proteolytic activation and subsequent lipogenesis gene expression by OA-NO 2 . These results were further supported by histological analysis and quantification of lipid accumulation, lobular inflammation (F4/80 staining) and fibrosis (collagen deposition, αSMA staining) as well as established parameters of liver damage (ALT). In vitro studies indicate that OA-NO 2 inhibits TG biosynthesis and accumulation in hepatocytes and inhibits fibrogenesis in human stellate cells. Interpretation OA-NO 2 improve steatohepatitis and fibrosis and may constitute an effective therapeutic approach against advanced NAFLD that warrants further clinical evaluation.

Effect of Carotenoids from Phaeodactylum tricornutum on Palmitate-Treated HepG2 Cells

“…In accordance with the present study, previous studies using HepG2 cells treated for 24 h with palmitate at 250 µM or 300 µM showed an increase in the expression of enzymes involved in the oxidation and de novo synthesis of fatty acids such as CPT1A and SCD [ 41 , 52 ]. Although our analyses showed no significant change in the mRNA levels of lipogenic genes ( ACACA , DGAT1 , FASN and LXR/NR1H3 ) in our cellular model of NAFLD, the mRNA levels of CPT2 and ACAT1 / SOAT1 were increased in agreement with in vivo studies [ 53 , 54 ].…”

Rodent Models of Nonalcoholic Fatty Liver Disease

“…One publications proved the effect of nitrooleic acid in experimental mice models of NASH. The administration of nitro-oleic acid inhibited hepatic triglyceride accumulation, as well as liver steatosis and fibrosis [131]. Sawada et al [96] observed that administration with clinically equivalent doses of losartan (30 mg/ kg/day) significantly ameliorated hepatic fibrosis and suppressed the activation of hepatic stellate cells in a rat model of NASH induced by CDAA.…”

Nitro-Oleic Acid in Seeds and Differently Developed Seedlings of Brassica napus L.

“…Due to its role in animal signal transduction [17][18][19] NO 2 -OA is the most intensively studied NO 2 -FA with potent anti-inflammatory effects [20]. Studies in animal models pointed out the protective role of NO 2 -OA in cardiovascular, renal, and metabolic diseases [10,21,22], therefore its therapeutic application is promising. Identifying plant-derived dietary sources of NO 2 -FAs, specially the well-studied NO 2 -OA and its beneficial effects, would constitute a suitable way to access to the valuable properties described for these relevant molecules.…”