MitoNEET Deficiency Alleviates Experimental Alcoholic Steatohepatitis in Mice by Stimulating Endocrine Adiponectin-Fgf15 Axis

Abstract

MitoNEET (mNT) (CDGSH iron-sulfur domain-containing protein 1 or CISD1) is an outer mitochondrial membrane protein that donates 2Fe-2S clusters to apo-acceptor proteins. In the present study, using a global mNT knock-out (mNTKO) mouse model, we investigated the in vivo functional role of mNT in the development of alcoholic steatohepatitis. Experimental alcoholic steatohepatitis was achieved by pair feeding wild-type (WT) and mNTKO mice with Lieber-DeCarli ethanol-containing diets for 4 weeks. Strikingly, chronically ethanol-fed mNTKO mice were completely resistant to ethanol-induced steatohepatitis as revealed by dramatically reduced hepatic triglycerides, decreased hepatic cholesterol level, diminished liver inflammatory response, and normalized serum ALT levels. Mechanistic studies demonstrated that ethanol administration to mNTKO mice induced two pivotal endocrine hormones, namely, adipose-derived adiponectin and gut-derived fibroblast growth factor 15 (Fgf15). The elevation in circulating levels of adiponectin and Fgf15 led to normalized hepatic and serum levels of bile acids, limited hepatic accumulation of toxic bile, attenuated inflammation, and amelioration of liver injury in the ethanol-fed mNTKO mice. Other potential mechanisms such as reduced oxidative stress, activated Sirt1 signaling, and diminished NF-κB activity also contribute to hepatic improvement in the ethanol-fed mNTKO mice. In conclusion, the present study identified adiponectin and Fgf15 as pivotal adipose-gut-liver metabolic coordinators in mediating the protective action of mNT deficiency against development of alcoholic steatohepatitis in mice. Our findings may help to establish mNT as a novel therapeutic target and pharmacological inhibition of mNT may be beneficial for the prevention and treatment of human alcoholic steatohepatitis.