Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Attenuate Persistent Corneal Epithelial Injury by Promoting Retinal Neural-Like Cell Proliferation and Hindering Their Differentiation

Objective: Persistent corneal epithelial defect (PED) is still a challenge to human which is difficultly cured, normally requiring long-term follow-up. Herein, this study aimed at exploring the potential role of bone marrow mesenchymal stem derived exosomes (BMSC-exos) in persistent corneal epithelial injury and its underlying mechanism. Methods: After characterization of BMSC-exos, RGC-5 cell viability was determined by MTT assay and BMSCs surface markers were analyzed by flow cytometry. Additionally, RT-qPCR and Western blot analysis measured miR-150-5p, Brn3, Islet-1, and PCNA expression. Double luciferase assays were conducted to evaluate the targeting relationship between LncRNA-MIAT and miR-150-5p. Results: Presented in ellipsoidal or cup shape, BMSC-exos were positive to BMSCs-specific markers CD29 and CD90, and cell surface markers CD9 and CD63 could be detected on exosomes. Importantly, treatment with BMSC-exos significantly promoted the proliferation of retinal ganglion cells (RGCs) and hindered cell differentiation. Interestingly, down-regulating lncRNA MIAT exerted the same effect as BMSC-exos, increasing cell viability, and decreasing the expression of differentiation-related proteins Brn3 and ISL1. Bioinformatics software predicted miR-150-5P as specific target genes of lncRNA MIAT, and the relative luciferase activity of miR-150-5P+MIAT-WT co-transfection group was lower. Conclusions: BMSC-exos improve PED when targeting and regulating miR-150-5p expression through lncRNA MIAT to up-regulate the expression of PCNA in RGC-5 cells, and down-regulate the expression of Brn3 and ISL1.