ASPP2 deficiency attenuates lipid accumulation through the PPARγ pathway in alcoholic liver injury

The initial stage of alcoholic liver disease (ALD) is hepatic steatosis. Recent studies have highlighted a possible role for Apoptosis-stimulating protein 2 of p53 (ASPP2) in regulating hepatic lipid metabolism in nonalcoholic fatty liver (NAFLD). However, whether ASPP2 regulates alcohol-induced lipid accumulation and its mechanisms remain unclear. To explore that, we establish an alcoholic liver injury model in vivo and in vitro. The clinical specimens were collected from liver tissues of patients with alcoholic liver disease. Lipid metabolism was detected by HE staining, oil red O staining and qPCR; and ASPP2-peroxisome proliferator-activated receptor γ (PPARγ) signaling pathways were detected by western blot and immunohistochemical staining. We found that both ASPP2 and PPARγ expression increased in patients and mouse models with ALD. We also discovered the reduction of ASPP2 significantly inhibited the expression of PPARγ and alleviated alcohol-induced hepatic lipid accumulation and liver injury in vivo and in vitro. Mechanistically, the PPARγ agonist reversed the protective effect of ASPP2 downregulation on hepatic steatosis and liver injury, while the opposite results were observed using PPARγ inhibitor. In conclusion, ASPP2 exacerbates ethanol-induced lipid accumulation and hepatic injury by upregulating the PPARγ signaling pathway, thus promoting the occurrence and development of ALD.