MicroRNA-133b Inhibition Restores EGFR Expression and Accelerates Diabetes-Impaired Wound Healing

Diabetic foot ulcers (DFUs) are caused by impairments in peripheral blood vessel angiogenesis and represent a great clinical challenge. Although various innovative techniques and drugs have been developed for treating DFUs, therapeutic outcomes remain unsatisfactory. Using the GEO database, we obtained transcriptomic microarray data for DFUs and control wounds and detected a significant downregulation of epidermal growth factor receptor (EGFR) in DFUs. We cultured human umbilical vein endothelial cells (HUVECs) and noted downregulated EGFR expression following high-glucose exposure in vitro. Further, we observed decreased HUVEC proliferation and migration and increased apoptosis after shRNA-mediated EGFR silencing in these cells. In mice, EGFR inhibition via focal EGFR-shRNA injection delayed wound healing. Target prediction analysis followed by dual-luciferase reporter assays indicated that microRNA-133b (miR-133b) is a putative upstream regulator of EGFR expression. Increased miR-133b expression was observed in both glucose-treated HUVECs and wounds from diabetes patients, but no such change was observed in controls. miR-133b suppression enhanced the proliferation and angiogenic potential of cultured HUVECs and also accelerated wound healing. Although angiogenesis is not the sole mechanism affected in DFU, these findings suggest that the miR-133b-induced downregulation of EGFR may contribute to delayed wound healing in diabetes. Hence, miR-133b inhibition may be a useful strategy for treating diabetic wounds.