miR-29b-3p promotes the recovery of alkali-burned cornea by targeting Ddx3x.

Abstract

Corneal alkali burns often cause vision impairment by triggering excessive inflammation and fibrosis, which compromise corneal transparency. Given miR-29b-3p's anti-inflammatory and anti-fibrotic properties, this study evaluated its therapeutic potential in corneal alkali injury. A murine corneal alkali burn model was established, and differentially expressed proteins were analyzed using liquid chromatography-mass spectrometry (LC-MS) at 24 h and 1-week post-injury. The results showed corneas exhibited both continuous and phase-specific pathway alterations during different stages of alkali burn recovery. We overexpressed miR-29b-3p in primary mouse bone marrow mesenchymal stem cells and isolated miR-29b-3p-enriched exosomes for delivery. Treatment with miR-29b-3p significantly accelerated corneal epithelial repair, reduced edema, and improved histological outcomes compared to controls. Bioinformatic analysis identified Ddx3x, Vcl, Col1a1, and Col6a2 as key candidate targets of miR-29b-3p. Among these, Ddx3x exhibited significant downregulation upon miR-29b-3p treatment in both murine corneas and human corneal epithelial cells (HCE). A dual-luciferase assay confirmed direct binding of miR-29b-3p to the 3'UTR of Ddx3x, suppressing its expression. Gene set enrichment analysis (GSEA) revealed that Ddx3x upregulates biosynthetic and secretory pathways while suppressing myofibril assembly. These findings identify miR-29b-3p as a promising therapeutic agent for corneal alkali burns, with Ddx3x as a critical downstream target. This study provides novel mechanistic insights into corneal alkali burn and proposes potential target for clinical intervention.