IFN‐γ enhances the therapeutic efficacy of MSCs‐derived exosome via miR‐126‐3p in diabetic wound healing by targeting SPRED1

Abstract Background and Aims The traditional treatment of diabetic wounds is unsatisfactory. Exosomes isolated from bone marrow mesenchymal stem cells (BMSCs) promote the healing of diabetic wounds. However, whether the exosomes secreted by interferon (IFN)‐γ‐pretreated BMSCs have an enhanced therapeutic effect on diabetic wound healing and the relevant mechanisms remain unclear. Methods In this study, we isolated exosomes from the corresponding supernatants of BMSCs with (IExos) or without IFN‐γ treatment (NExos). Human umbilical vein endothelial cells (HUVECs) were used to investigate the proliferation, migration, and tube formation under different treatments in vitro. Diabetic mice were induced by intraperitoneal administration of streptozotocin, and a circular full‐thickness dermal defect was then made on the back of each mouse, followed by a multisite subcutaneous injection of phosphate buffered saline or exosomes. Hematoxylin–eosin (H&E) staining, Masson's trichrome staining, and histological analysis were performed to assess the speed and quality of wound healing. Results NExos treatment accelerated the healing of diabetic wounds by promoting angiogenesis in vivo and in vitro, and IExos exhibited superior therapeutic efficiency. MicroRNA (miR)‐126‐3p was significantly increased in IExos, and exosomal miR‐126‐3p promoted angiogenesis and diabetic wound healing via its transfer to HUVECs. miR‐126‐3p regulates SPRED1 by directly targeting the 3′‐UTR. Mechanistically, IFN‐γ‐pretreated BMSCs secreted miR‐126‐3p‐enriched exosomes, which enhanced the function of HUVECs and promoted angiogenesis via the SPRED1/Ras/Erk pathway. Conclusion Exosomal miR‐126‐3p secreted from IFN‐γ‐pretreated BMSCs exhibited higher therapeutic efficacy than NExos in diabetic wound healing by promoting angiogenesis via the SPRED1/Ras/Erk axis.