Fig. 3

Gene expression of PNPLA and H3K9ac level of PNPLA3 promoter were regulated by SIRT1 in starved (fasted) HepG2 cells. A and B Relative mRNA of PNPLA3 (A) measured by qPCR and protein level of SIRT1 (B) detected by western blot in a cellular model to simulate fasting/refeeding in mice. C-E HepG2 cells were pretreated with siRNA-Control or si-SIRT1, followed by treatment of fasting and refeeding. Relative mRNA of PNPLA3 (C) was measured by qPCR. The protein level of SIRT1 (D) was detected by western blot. The recruitment of H3K9ac onto the PNPLA3 promoter (E) was detected by ChIP-qPCR using an anti-H3k9Ac antibody. Rabbit IgG was used as a mock antibody for negative control. The recruitment is expressed as fold enrichment over IgG. Biological replicates (N = 3) were performed per group. Quantitative data are presented as the means ± SD (N = 3 independent experiments). Quantitative analysis of gray value on bands of western blot was performed using Image-Pro Plus software. Ctrl: cells incubated in media containing 5.5 mM glucose and 10% fetal bovine serum; Fasted: cells incubated in glucose- and serum-free medium for 12 h; Refed: cells incubated in glucose- and serum- free medium for 12 h and followed by additional 12-h incubation with re-addition of 25 mM glucose. **P < 0.01; ***P < 0.001