Fig. 7: Inhibiting the release of ENDOG represses oleic acid-induced lipid accumulation.

a, b Representative images of costaining of HSP60/ENDOG and subcellular fraction isolation. HepG2 cells were pretreated with 20 μM VBIT-12 (VDAC inhibitor) for 4 h and then treated with 200 μM oleic acid for 24 h. The red puncta in the dotted circle indicate that ENDOG is released from the mitochondria. S, short time exposure; L, long time exposure. c, d Western blot and quantitative results of ER stress-related proteins, FAS/ACC, and AKT-ACLY activation. HepG2 cells were pretreated with 20 μM VBIT-12 (VDAC inhibitor) for 4 h and then treated with 200 μM oleic acid for 24 h. n = 4 biologically independent samples. e–g Measurement of triglycerides, Nile red staining, and the quantitative results of lipid area. HepG2 cells were pretreated with 20 μM VBIT-12 (VDAC inhibitor) for 4 h and then treated with 200 μM oleic acid for 24 h. n = 4 biologically independent samples for triglycerides measurement and 10 for Nile red staining. h Schematic diagram of ENDOG mediated NAFLD under the HFD chow feeding. HFD promotes the release of ENDOG from the mitochondria. Cytoplasm located ENDOG competitively binds with 14-3-3γ, which makes 14-3-3γ disassociate from Rictor and activates the mTORC2-AKT-ACLY axis, resulting in the production of acetyl-CoA. In addition, cytoplasmic ENDOG also translocates into the ER and interacts with Bip, which releases IRE1a and PERK to activate ER stress and ACC/FAS expression. Increased acetyl-CoA and lipid synthesis enzymes (ACC/FAS) enhanced lipid accumulation. Finally, increased triglyceride and ER stress promote the development of HFD-induced NAFLD. Three experiments were repeated independently with similar results in (a, b). Statistical significance was determined by unpaired Student’s t-test (two-tailed) in (d, e, g); error bars are mean ± SD. Source data and exact P value were provided in a Source data file. *P < 0.05; **P < 0.01; ***P < 0.001.