The truncated splice variants, NT-PGC-1alpha and PGC-1alpha4, increase with both endurance and resistance exercise in human skeletal muscle
2013 (English)In: Physiological Reports, ISSN 2051-817X, Vol. 1, no 6, e00140 Page 1-e00140 Page 9 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2013. Vol. 1, no 6, e00140 Page 1-e00140 Page 9 p.
Medical and Health Sciences
Research subject Medicine/Technology
IdentifiersURN: urn:nbn:se:gih:diva-3181DOI: 10.1002/phy2.140OAI: oai:DiVA.org:gih-3181DiVA: diva2:683315