Fig. 3

ATF4 is involved in the reduction of PGC-1α caused by ER stress in myotubes. A mRNA levels and B palmitate oxidation to CO₂ in LHCN-M2 cultured myotubes transfected with pCMV-GFP-C2 (pGFP-C2) or pCMV-ATF4 (pATF4). Data are presented as the mean ± SEM (n = 6 per group). C mRNA and D palmitate oxidation to CO₂ in LHCN-M2 cultured myotubes transfected with control siRNA or ATF4 siRNA. E, F PGC-1α or G, H FGF21 mRNA levels in LHCN-M2 cultured myotubes transfected with control, ATF4 or TRIB3 siRNA and incubated with or without (control) 0.5 mM palmitate or 2 µg/ml of tunicamycin for 16 h. Data are presented as the mean ± SEM (n = 3–6 per group). *p < 0.05, **p < 0.01 and ***p < 0.001 versus control. ^#p < 0.05 and ^##p < 0.01 versus control siRNA