Development of a novel RNAi therapy:Engineered miR-31 exosomes promoted the healing of diabetic wounds

Rationale:Chronic wounds associated with diabetes exact a heavy burden on individuals and society and do not have a specific treatment.Exosome therapy is an extension of stem cell therapy,and RNA interference(RNAi)-based therapy is a type of advanced precision therapy.Based on the discovery of chronic wound-related genes in diabetes,we combined exosome therapy and RNAi therapy through an engineering approach for the treatment of diabetic chronic wounds.Methods:We combined exosome therapy and RNAi therapy to establish a precision therapy for diabetes-associated wounds via an engineered exosome approach.Results:First,chronic diabetic wounds express low levels of miR-31-5p compared with nondiabetic wounds,and an miR-31-5p mimic was shown to be effective in promoting the proliferation and migration of three wound-related cell types in vitro.Second,bioinformatics analysis,luciferase reporter assays and western blotting suggested that miR-31-5p promoted angiogenesis,fibrogenesis and reepithelization by inhibiting factor-inhibiting HIF-1(HIF1AN,also named FIH)and epithelial membrane protein-1(EMP-1).Third,engineered miR-31 exosomes were generated as a miR-31-5p RNAi therapeutic agent.In vivo,the engineered miR-31 exosomes promoted diabetic wound healing by enhancing angiogenesis,fibrogenesis and reepithelization.Conclusion:Engineered miR-31 exosomes are an ideal disease pathophysiology-initiated RNAi therapeutic agent for diabetic wounds.