Abstract 13182: Inhibition of Microrna-466 and Microrna-200 Accelerates Wound Healing by Decreasing Endothelial Cell Permeability

Abstract

Introduction: Endothelial cell (EC) permeability is essential to vascular homeostasis in diabetes. MicroRNAs (miRs) are critical gene regulators whose roles in the EC permeability have yet to be elucidated. It remains unclear whether miR-200 and miR-466 regulate EC permeability. We hypothesized that the inhibition of miR-466 and miR-200 can restore vascular integrity and accelerate wound healing via targeting Claudin-5. Methods and Results: Human dermal microvascular ECs from healthy subjects and type 2 diabetic patients at passages 5-7 were cultured in vitro. The EC permeability was significantly increased by high glucose (25mM)or silencing Claudin-5 as measured by FITC-Dextran Transwell assay (n = 5, p<0.05). Claudin-5 protein levels were significantly reduced in diabetic ECs and healthy ECs exposed to high glucose. The reduction of Claudin-5 protein was restored by the inhibition of miR-466 (Western Blot, n = 5, p<0.05), though both miR-200 and miR-466 are directly bound with the 3’ UTR of Claudin-5 mRNA (luciferase 3’UTR reporter assay). Furthermore, silencing Claudin-5 diminished the protection of miR-200/miR-466 inhibition on EC permeability damaged by high glucose (n = 5, p<0.05). In the in vivo study, the topical application of miR-200 and miR-466 inhibitors showed enhanced efficacy in accelerating the closure of a 7-mm full-thickness excisional wound in a type 2 diabetic (db/db) mouse model, with concomitant robust wound capillary formation (CD31 immunochemistry), compared with the topical application of miR-200 inhibitor alone (n = 5, p<0.05). Claudin-5 levels were increased in the wounds receiving miR-466 inhibitor alone or both miR-200 and miR-466 inhibitors (n = 5, p<0.05). Conclusions: Our study demonstrated the potentially effective approach of miR-200/miR-466 cocktail inhibition to restore vascular integrity and tissue repair in hyperglycemia. This may provide a novel therapeutic strategy targeting miRs for the treatment of wound healing in diabetes.