Figure 7.

Induction of autophagy by MTORC1 inactivation suppresses MCD diet-induced hepatic steatosis, inflammation, and fibrosis in txnip-KO livers. WT and txnip-KO mice were fed an MCD diet for 4 w, with rapamycin (5 mg/kg/d) applied during the final week (n = 5–7 per group). (A) Western blot analysis of p-RPS6KB1, RPS6KB1, and nuclear TFEB. (B) Immunoblotting of MAP1LC3B and SQSTM1. (C) Hepatic expression of FAO-related genes. (D) H&E and Oil Red O staining. Scale bar: 50 μm. Ten fields (final magnification, × 400) were randomly selected for each sample, and the positive area in each image was measured. (E) Hepatic TG levels. (F) Immunohistochemical detection of ADGRE1 (arrow). Scale bar: 50 μm. Ten fields (final magnification, × 400) were randomly selected for each sample, and positive cells in each image were counted. (G) Sirius red staining. Ten fields (final magnification, × 400) were randomly selected for each sample, and the positive area in each image was measured. Scale bar: 50 μm. (H) A proposed model of TXNIP-mediated autophagy and FAO in NASH pathogenesis. In NASH, an elevated FFA flux upregulates TXNIP expression in hepatocytes. TXNIP promotes PRKAA phosphorylation, MTORC1 inactivation, and TFEB nuclear translocation, leading to autophagy induction and FAO. This could contribute to MCD diet-induced steatosis, inflammation, and fibrosis. Values represent means ± SEM. *P < 0.05, **P < 0.01 versus WT; ^#P < 0.05, ^##P < 0.01 versus the same genotype control