Role of USF1 in activating CYBA transcription and influencing NADPH-ROS-mediated oxidative stress and lipid accumulation in non-alcoholic fatty liver disease

Abstract

Nonalcoholic fatty liver disease (NAFLD) progression is relevant to oxidative stress, while NADPH oxidase can produce ROS. This study explored how the upstream stimulatory factor 1 (USF1) regulates cytochrome b-245 alpha chain (CYBA) expression through the NADPH-ROS pathway and its impact on oxidative stress and lipid accumulation in NAFLD. Bioinformatics analysis identified CYBA as a gene with altered expression in NAFLD. Mouse and cell models of NAFLD were established through high-fat diet (HFD) and palmitic acid (PA) treatment respectively. CYBA and USF1 expression was modulated using RNA interference, and their effects on NAFLD progression were then examined. ChIP and dual-luciferase reporter assays were performed to confirm the transcriptional regulation of CYBA by USF1. Elevated CYBA expression was observed in NAFLD. Reduced NADPH oxidase activity, oxidative stress, lipid accumulation, and inflammation were observed in NAFLD models after knocking down CYBA. USF1 was found to bind to the CYBA promoter and activate its transcription. Similar effects as CYBA knockdown on NAFLD were achieved by knocking down USF1. The protective impacts of USF1 silencing on NAFLD were reversed by overexpressing CYBA. In summary, this study demonstrates that USF1 mediates the transcriptional activation of CYBA, increasing NADPH-ROS-derived oxidative stress and lipid accumulation in NAFLD.