The inhibition effects of insulin on BMP2-induced muscle heterotopic ossification.

Bone morphogenetic proteins (BMPs) play an important role in regulating osteoblastic differentiation and bone formation. But the diffuse of BMPs into muscle tissues around bone injury sites often leads to heterotopic ossification, which has been regarded as one of major side-effects of BMP implementation in bone defect patients. It raises great demands for exploring effective methods that preventing BMP-induced heterotopic ossification while not interrupting the osteoinductive activity of BMPs for in situ bone defect repair. Here we found insulin, a positive regulator for bone regeneration, inhibited BMP2-induced muscle heterotopic ossification by suppressing the expression of bone transcription factor Osterix. By analyzing downstream molecules of insulin pathway, we found AKT/mTOR/GSK3 signaling was responsible for the inhibition of insulin on BMP2-induced ossification, and GSK3 inhibitor SB216763 attenuated BMP2-induced muscle heterotopic ossification. The data might shed light on developing effective clinical therapy for inhibiting muscle heterotopic ossification when BMPs were used bone defect repair.