Abstract
Recently, a truncated peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) splice variant, PGC-1α4, that originates from the alternative promoter was shown to be induced by resistance exercise and to elicit muscle hypertrophy without coactivation of “classical” PGC-1α targets involved in mitochondrial biogenesis and angiogenesis. In order to test if distinct physiological adaptations are characterized by divergent induction of PGC-1α splice variants, we investigated the expression of truncated and nontruncated PGC-1α splice variants and PGC-1α transcripts originating from the alternative and the proximal promoter, in human skeletal muscle in response to endurance and resistance exercise. Both total PGC-1α and truncated PGC-1α mRNA expression were increased 2 h after endurance (P < 0.01) and resistance exercise (P < 0.01), with greater increases after endurance exercise (P < 0.05). Expression of nontruncated PGC-1α increased significantly in both exercise groups (P < 0.01 for both groups) without any significant differences between the groups. Both endurance and resistance exercise induced truncated as well as nontruncated PGC-1α transcripts from both the alternative and the proximal promoter. Further challenging the hypothesis that induction of distinct PGC-1α splice variants controls exercise adaptation, both nontruncated and truncated PGC-1α transcripts were induced in AICAR-treated human myotubes (P < 0.05). Thus, contrary to our hypothesis, resistance exercise did not specifically induce the truncated forms of PGC-1α. Induction of truncated PGC-1α splice variants does not appear to underlie distinct adaptations to resistance versus endurance exercise. Further studies on the existence of numerous splice variants originating from different promoters are needed.
Highlights
In the last decade, technological advancements have yielded new tools, creating the possibility to identify and characterize regulatory factors controlling muscle plasticity
A truncated peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1a) splice variant, PGC-1a4, that originates from the alternative promoter was shown to be induced by resistance exercise and to elicit muscle hypertrophy without coactivation of “classical” PGC-1a targets involved in mitochondrial biogenesis and angiogenesis
In order to test if distinct physiological adaptations are characterized by divergent induction of PGC-1a splice variants, we investigated the expression of truncated and nontruncated PGC-1a splice variants and PGC-1a transcripts originating from the alternative and the proximal promoter, in human skeletal muscle in response to endurance and resistance exercise
Summary
Technological advancements have yielded new tools (e.g., tissue knockout models, microarray, and bioinformatics), creating the possibility to identify and characterize regulatory factors controlling muscle plasticity. One such emerging factor has been the transcriptional coactivator peroxisome proliferatoractivated receptor gamma coactivator-1 alpha (PGC-1a). Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
