Figure 6: In vitro functional analysis of NT-PGC-1α-a. (a) NT-PGC-1α promotes oxidative phenotyping myotube fiber and the skeletal muscle mass growth. NT-PGC-1α-a induces the expression of MHC I, MHC II a, Glut4, and IGF-1 mRNA and inhibits the expression of MHC II b, MHC II x, and Myostatin mRNA in differentiated C2C12 cells transfected with plasmid NT-PGC-1α-a/pcDNA3.1. (b) NT-PGC-1α-a increases mitochondrial function through induction of ATP5B, COX5B, and Cyc1 mRNA expression in the same cells and conditions above. Relative gene expression was quantified by real-time PCR and normalized to the expression of cyclophilin with method, compared to control cells transfected with empty vector pcDNA3.1. Values are means ± S.E. ( ). versus ctrl. (c) NT-PGC-1α-a enhances the activity of citrate synthase in C2C12 myotube cells transfected with plasmid NT-PGC-1α-a/pcDNA3.1. The activity is normalized to the total protein content of the sample used in the assay. Normalized data are presented as means ± S.E. versus ctrl. ( , significantly different from control).