Adaptation of Resistance Training is impaired in muscle-specific PGC-1α overexpressing mice

Abstract

Resistance training (RT) is important for skeletal muscle health. However, compared with RT implemented alone, concurrent training can attenuate RT adaptations. We verify the effects of RT on muscle-enriched or hypertrophy-related miRNAs, mammalian target of rapamycin complex 1 (mTORC1) anabolic signaling proteins, and oxidative metabolism-related proteins in mice with different endurance muscle Phenotype. In the present study, we found that muscle-specific overexpression of PGC-1alpha attenuated RT adaptations and resulted in different expression of miR-222-3p and miR-206-3p after RT. The expression level of miR-206-3p and miR-222-3p in Wt+ mice (wild-type trained mice) was significantly higher than that in Tg+ mice (MCK-PGC-1α transgenic trained mice). This suggested that discordant miR-222-3p and miR-206-3p expression levels after RT may play a role in the mechanism contributing to the interference effects. With regard to protein expression,there was no difference in mTORC1 between the genotypes. Furthermore, the levels of parameters for oxidative metabolism were significantly higher in Tg mice than in Wt mice. Our study indicated miR-222-3p and miR-206-3pas novel molecules that could provide a new research direction into the mechanisms underlying the concurrent training effect.