Inhibition of microRNA‐129‐5p expression ameliorates ultraviolet ray‐induced corneal epithelial cell injury via upregulation of EGFR

Abstract Existing evidence has highlighted the effect of ultraviolet light radiation leading to corneal epithelium impairment. During this study, we aim to investigate the effect of microRNA‐129‐5p (miR‐129‐5p) on the wound healing process of corneal epithelial cells (CECs) induced by ultraviolet rays in mice by targeting epidermal growth factor receptor (EGFR). First, mouse models of ultraviolet ray‐induced CEC injury were established and intrastromally injected with different mimic, inhibitor, and short interfering RNA (siRNA) to detect the effect of miR‐129‐5p on CEC injury. Subsequently, the corneal tissues were obtained to detect the antioxidant ability and EGFR‐positive expression rate. The dual‐luciferase reporter gene assay was used to test whether EGFR could directly target miR‐129‐5p. To further investigate the specific mechanism of miR‐129‐5p and EGFR in CEC injury, CECs were cultured and transfected with miR‐129‐5p mimic, miR‐129‐5p inhibitor, siRNA‐EGFR, and miR‐129‐5p inhibitor + siRNA‐EGFR. miR‐129‐5p has been proven to directly target EGFR. Inhibition of miR‐129‐5p is able to increase the antioxidant capacity, EGFR‐positive rate and the expressions of EGFR, B‐cell lymphoma‐2, zonula occluden‐1, occludin, and keratinocyte growth factor‐2, but decrease the expression of vascular endothelial growth factor, BCL2‐associated X protein, interleukin (IL)‐1β, and IL‐4. Inhibition of miR‐129‐5p arrests cells at the S and G2 phases and decreases apoptosis. Our study provides evidence stating that inhibiting miR‐129‐5p and upregulating EGFR could aid in the repair of mice CEC injury induced by ultraviolet radiation. Therefore, inhibition of miR‐129‐5p might provide a basic theory in the repair of CEC injury caused by ultraviolet rays.