Intrinsic muscle stem cell dysfunction underlies functional deficits in models of type 1 diabetes.

Muscle function and regeneration are impaired in type 1 diabetes, but whether this arises directly from muscle stem cell (MuSC) dysfunction has not been addressed. Here, we utilized three-dimensional MuSC cultures (micromuscles) to demonstrate that hyperglycemia drives deficits in muscle stem cell function, leading to impaired force production in differentiated myotubes. The functional capacity of skeletal muscle was shown to decline after repeated bouts of injury in mouse models of type 1 diabetes, and this was replicated in micromuscles derived from MuSCs isolated from diabetic mice, indicating MuSC dysfunction was linked to poor muscle regeneration and function. The loss of force producing capacity was associated with impaired myotube hypertrophy in vitro and in vivo after injury. Furthermore, poor muscle regeneration was exacerbated by a loss of MuSC number due to aberrant activation, even in the absence of injury. Deficits in MuSC function and number could be rescued by early treatment with the glucose-lowering drug dapagliflozin, indicating that MuSC defects were driven by exposure to a hyperglycemic environment. The findings reveal that MuSC dysfunction contributes to muscle functional deficits in models of type 1 diabetes.