PGC-1α MRNA Isoform-specific Response To Exercise And Cold

Abstract

Cold exposure in conjunction with aerobic exercise has been shown to increase the gene expression of PGC-1α, the master regulator of mitochondrial biogenesis. PGC-1α can be expressed as multiple different isoforms due to alternative splicing mechanisms, including the truncated NT-PGC-1α isoform. These isoforms have differing structures and functions but relatively little about the specificity and response is known. PURPOSE: Determine the difference of PGC-1α isoform expression following an acute bout of cycling in cold and room temperature conditions. METHODS: 8 male participants cycled for 1 hour at 65% Wmax at -2°C and 20 °C. A muscle biopsy was taken from the vastus lateralis before, 3 h post, and 6 h post exercise. qRT-PCR was used to analyze gene expression of total PGC-1α and NT-PGC-1α expression. RESULTS: Gene expression of both total PGC-1α and NT-PGC-1α increased due to the exercise intervention at both 3 h and 6 h time points (p<0.05), with mRNA expression peaking at 3 h (p<0.05). At 3 h total PGC-1α was higher in the cold (13.2 ± 6.3 fold increase) compared to room temperature (7.4 ± 2.0 fold increase, p = 0.03). NT-PGC-1α was also higher in cold (20.8 ± 12.5 fold increase) compared to room temperature at 3 h (10.7 ± 3.7 fold increase, p=0.029). Total PGC-1α and NT-PGC-1α were similar in cold and room temperature at 6 h (p>0.05). CONCLUSION: Exercise and cold exposure induced alterations in gene expression for total-PGC-1α and its truncated isoform, NT-PGC-1α. It appears that NT-PGC-1α contributes to the reported alterations in the cold-induced PGC-1α exercise response.