Resistance exercise, skeletal muscle FOXO3A, and 85-year-old women

This investigation examined Akt-FOXO3A signaling in young women (YW) and old women (OW) before and after 12 weeks of high-intensity resistance training. Muscle biopsies were taken from the vastus lateralis before and immediately after resistance exercise (RE) in the untrained and trained states. In response to RE in YW and OW, phospho Akt Thr308 increased in untrained and trained states, with no change on Ser473 site. FOXO3A-Ser253 site was dephosphorylated in untrained state among YW and OW, and nuclear phospho-FOXO3A increased mainly in YW in trained state. In the basal state, OW displayed lower cytosolic phospho-FOXO3A before training, higher total nuclear FOXO3A, and a trend for higher nuclear-to-cytosolic FOXO3A ratio versus YW after 12 weeks. Basal level MuRF-1 and myostatin mRNA decreased in YW, while OW increased myostatin mRNA after 12-weeks. These data suggest that FOXO3A signaling and FOXO3A-related target gene expression are altered in OW and may partially explain the attenuated training adaptations previously reported in these octogenarian women.