MicroRNA Expression in Retinal Ganglion Cells after Induction of Hypoxic Injury

Purpose: This study investigated the expression of microRNA (miRNA) in a retinal ganglion cell (RGC) line following hypoxic injury, compared with a control group. Hypoxia-induced oxidative stress plays a critical role in the pathogenesis of glaucoma.Methods: A rat RGC cell line was used, and oxidative stress was induced using a hypoxic chamber with 1% O₂. RNA sequencing was performed on RNA samples extracted from RGCs subjected to hypoxic injury and from the control group. To assess the effects of hypoxia on miRNA-related gene expression, quantitative real-time polymerase chain reaction (qPCR) was conducted.Results: A total of 73 mature miRNAs were identified in hypoxia-treated RGC-5 cells (fold change > 2 or < 0.5, p < 0.05). Among these, 20 miRNAs exhibited significant changes compared with the normoxia group. Specifically, 11 miRNAs (miR-122-5p, miR-135a-5p, miR-181d-5p, miR-875, miR-3574, miR-3473, miR-6316, miR-325-3p, miR-206-3p, miR-210-3p, and miR-598-3p) were significantly upregulated, whereas 9 miRNAs (let-7a-1-3p, let-7c-1-3p, let-7c-2-3p, let-7e-3p, let-7f-2-3p, miR-181b-1-3p, miR-339-5p, miR-503-5p, and miR-484) were significantly downregulated. Among the target genes of these differentially-expressed miRNAs, 11 mRNAs associated with apoptosis mechanisms or protein regulation were selected for qPCR analysis. Hypoxia significantly altered the expression of these mRNAs, with six showing upregulation and five showing downregulation (p < 0.05).Conclusions: Hypoxic injury in RGCs induces significant changes in miRNA expression, compared with control RGCs. Furthermore, hypoxia modulates the expression of mRNA in miRNA-related genes, highlighting the potential role of miRNAs in hypoxia-induced cellular responses in glaucoma pathogenesis.