[PDF][PDF] Myofiber androgen receptor increases muscle strength mediated by a skeletal muscle splicing variant of Mylk4

I Sakakibara, Y Yanagihara, K Himori, T Yamada… - Iscience, 2021 - cell.com
I Sakakibara, Y Yanagihara, K Himori, T Yamada, H Sakai, Y Sawada, H Takahashi, N Saeki…
Iscience, 2021cell.com
Androgens have a robust effect on skeletal muscles to increase muscle mass and strength.
The molecular mechanism of androgen/androgen receptor (AR) action on muscle strength is
still not well known, especially for the regulation of sarcomeric genes. In this study, we
generated androgen-induced hypertrophic model mice, myofiber-specific androgen receptor
knockout (cARKO) mice supplemented with dihydrotestosterone (DHT). DHT treatment
increased grip strength in control mice but not in cARKO mice. Transcriptome analysis by …
Summary
Androgens have a robust effect on skeletal muscles to increase muscle mass and strength. The molecular mechanism of androgen/androgen receptor (AR) action on muscle strength is still not well known, especially for the regulation of sarcomeric genes. In this study, we generated androgen-induced hypertrophic model mice, myofiber-specific androgen receptor knockout (cARKO) mice supplemented with dihydrotestosterone (DHT). DHT treatment increased grip strength in control mice but not in cARKO mice. Transcriptome analysis by RNA-seq, using skeletal muscles obtained from control and cARKO mice treated with or without DHT, identified a fast-type muscle-specific novel splicing variant of Myosin light-chain kinase 4 (Mylk4) as a target of AR in skeletal muscles. Mylk4 knockout mice exhibited decreased maximum isometric torque of plantar flexion and passive stiffness of myofibers due to reduced phosphorylation of Myomesin 1 protein. This study suggests that androgen-induced skeletal muscle strength is mediated with Mylk4 and Myomesin 1 axis.
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