Overexpression of PGC-1α Increases Fatty Acid Oxidative Capacity of Human Skeletal Muscle Cells
Figure 6
Deoxyglucose transport (a), glycogen synthesis (b) and mRNA expression (c) of GLUT1, GLUT4 and PDK4 in human myotubes infected with either empty vector or PGC-1α. (a): Cultured myotubes infected with either empty vector or PGC-1α were incubated with 1 mL/well of serum-free DMEM ± cytochalasin B 10 μM for 60 min, followed by a 15 min exposure to 2-deoxy-D-[3H]glucose (1 μCi/mL) with or without cytochalasin B, and with or without insulin, as described in Section 2. Values are normalized to the levels of uptake in control cells infected with empty vector and presented as means ± SEM of 4 experiments, representing 3 different donors, with 3 replicates each. *Statistically significant compared to basal uptake in control cells infected with empty vector () (b): Myotubes infected with either empty vector or PGC-1α were incubated for 2 h in serum-free DMEM (± insulin), and then exposed to D-[14C(U)]glucose ± insulin. After 60 min, the cells were washed three times with ice-cold PBS and lysed with 1 M NaOH. Synthesised glycogen was measured as described in Section 2. Values are presented as means ± SEM of 2 experiments, each representing one donor, with 3 replicates each. (c): mRNA expression of GLUT1, GLUT4 and PDK4. mRNA was isolated from cultured myotubes infected with either empty control vector or PGC-1α eight days after the onset of differentiation. Expression was assessed by RT-PCR, and values are presented as means ± SEM of 3 experiments, each representing one donor, with 3 replicates each, normalized to the levels of housekeeping gene 36B4. A fold change ≥2 or ≤0.5 was considered an increase or decrease in expression level, respectively.
