Dimethyloxaloylglycine-stimulated human bone marrow mesenchymal stem cell-derived exosomes enhance bone regeneration through angiogenesis by targeting the AKT/mTOR pathway

Abstract

Abstract Background Mesenchymal stem cell (MSC)-derived exosomes have been recognized as new candidate agents for treating critical-sized bone defects; they promote angiogenesis and may be an alternative to cell therapy. In this study, we evaluated whether exosomes derived from bone marrow-derived MSCs (BMSCs) preconditioned with a low dose of dimethyloxaloylglycine (DMOG), DMOG-MSC-Exos, exert superior proangiogenic activity in bone regeneration and the underlying mechanisms involved. Methods To investigate the effects of these exosomes, scratch wound healing, cell proliferation, and tube formation assays were performed in human umbilical vein endothelial cells (HUVECs). To test the effects in vivo, a critical-sized calvarial defect rat model was established. Eight weeks after the procedure, histological/histomorphometrical analysis was performed to measure bone regeneration, and micro-computerized tomography was used to measure bone regeneration and neovascularization. Results DMOG-MSC-Exos activated the AKT/mTOR pathway to stimulate angiogenesis in HUVECs. This contributed to bone regeneration and angiogenesis in the critical-sized calvarial defect rat model in vivo. Conclusions Low doses of DMOG trigger exosomes to exert enhanced proangiogenic activity in cell-free therapeutic applications.

Keywords

• Exosome
• Mesenchymal stem cell
• Bone regeneration
• Angiogenesis
• Dimethyloxaloylglycine
• Tissue engineering