Myostatin induces DNA damage in skeletal muscle of streptozotocin-induced type 1 diabetic mice.

One of the features of uncontrolled type 1 diabetes is oxidative stress that induces DNA damage and cell death. Skeletal muscle atrophy is also considerable in type 1 diabetes, however, the signaling mechanisms that induce oxidative stress culminating in muscle atrophy are not fully known. Here, we show that in Streptozotocin-induced diabetic wild type mice, hypo-phosphorylation of Akt, resulted in activation of Foxa2 transcription factor in the muscle. Foxa2 transcriptionally up-regulated Myostatin, contributing to exaggerated oxidative stress leading to DNA damage via p63/REDD1 pathway in skeletal muscle of Streptozotocin-treated wild type mice. In Myostatin(-/-) mice however, Streptozotocin treatment did not reduce Akt phosphorylation despite reduced IRS-1 signaling. Moreover, Foxa2 levels remained unaltered in Myostatin(-/-) mice, while levels of p63/REDD1 were higher compared with wild type mice. Consistent with these results, relatively less DNA damage and muscle atrophy was observed in Myostatin(-/-) muscle in response to Streptozotocin treatment. Taken together, our results for the first time show the role of Foxa2 in Myostatin regulation in skeletal muscle in diabetic mice. Altogether, these results demonstrate the mechanism by which Myostatin contributes to DNA damage in skeletal muscle of the diabetic mice that would lead to myofiber degeneration.