Targeting myostatin/activin A protects against skeletal muscle and bone loss during spaceflight.

Among the physiological consequences of extended space flight are loss of skeletal muscle and bone mass. One signaling pathway that plays an important role in maintaining muscle and bone homeostasis is that regulated by the secreted signaling proteins, myostatin and activin A. Here, we used both pharmacological and genetic approaches to investigate the effect of targeting myostatin/activin A signaling in mice that were sent to the International Space Station. We show that inhibition of myostatin/activin A signaling has a significant protective effect against microgravity-induced muscle and bone loss. These findings have implications for therapeutic strategies to combat the concomitant muscle and bone loss occurring in people afflicted with disuse atrophy on Earth as well as in astronauts in space, especially during prolonged missions.