MicroRNA-615-5p Regulates Angiogenesis and Tissue Repair by Targeting AKT/eNOS Signaling in Endothelial Cells

Abstract

Objective: In response to tissue injury, the appropriate progression of events in angiogenesis is controlled by a careful balance between pro- and anti-angiogenic factors; dysregulation of these factors may underlie impaired angiogenesis and pathological tissue repair. We aimed to identify and characterize microRNAs that regulate angiogenesis in response to tissue injury. Approach and Results: We show that in response to tissue injury, miR-615-5p is rapidly induced and serves as an anti-angiogenic miRNA by targeting endothelial cell (EC) VEGF-AKT/eNOS signaling in vitro and in vivo. MiR-615-5p expression is increased in wounds of diabetic db/db mice, in plasma of human subjects with acute coronary syndromes, and in plasma and skin of human subjects with diabetes. Ectopic expression of miR-615-5p markedly inhibited EC proliferation, migration, network tube formation in matrigel, and the release of nitric oxide, whereas miR-615-5p neutralization had the opposite effects. Mechanistic studies using transcriptomic profiling, bioinformatics, 3’-UTR reporter and miRNP-IP assays, and siRNA dependency studies demonstrate that miR-615-5p inhibits the VEGF-AKT/eNOS signaling pathway in ECs by targeting IGF2 and RASSF2. Local delivery of miR-615-5p inhibitors, markedly increased angiogenesis, granulation tissue thickness, and wound closure rates in db/db mice, whereas local delivery of miR-615-5p mimics impaired these effects. Finally, modulation of miR-615-5p expression dynamically regulated VEGF-induced AKT signaling and angiogenesis in human skin organoids as a model of tissue injury. Conclusion: These findings establish miR-615-5p as a regulator of VEGF-AKT/eNOS-mediated EC angiogenic responses, and that manipulating miR-615-5p expression could provide a new target for angiogenic therapy in response to tissue injury.