PIKE-A mediates TNF-α–induced mitochondrial respiratory change. A: A representative tracing of OCR measured in the control (Ad-Ctr), Ad-PIKE-A, or Ad-shPIKE C2C12 myotubes. The times of oligomycin, carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), and antimycin A plus rotenone injections are indicated by arrows (n = 4). B: Basal and maximal mitochondrial respirations of adenovirus-infected C2C12 myotubes (48 h) after 24-h 10 ng/mL TNF stimulation (*P < 0.05; **P < 0.01; ***P < 0.001, one-way ANOVA; n = 4–6). C: Mitochondrial DNA content in the adenovirus-infected C2C12 myotubes after PBS or TNF-α (10 ng/mL, 24 h) stimulation using real-time PCR methods (n = 3). Results were normalized with the amount of actin gene in each sample. D: Maximal mitochondrial respiration of adenovirus-infected C2C12 myotubes (48 h) after stimulation by various combinations of TNF-α (10 ng/mL, 24 h) and AMPK activator A769662 (100 μmol/L) (*P < 0.05, one-way ANOVA; n = 3).