Identification and Integrated Analysis of the miRNA-mRNA Regulatory Network in Lens from an H₂O₂-Induced Zebrafish Cataract Model

Purpose: This study aimed to explore the regulatory mechanisms of age-related cataract (ARC) formation.

Methods: Cataracts in zebrafish were induced by injecting hydrogen peroxide into the fish anterior chamber. The mRNA and miRNA expression profiles of the lens from H₂O₂-injected and PBS-injected zebrafishes were detected by RNA sequencing. The LIMMA package was applied to identify differentially expressed genes (DEGs). Gene Ontology categories were enriched by the R "cluster Profiler" package and Kyoto Encyclopedia of Genes and Genomes pathway enrichment was performed based on hypergeometric distribution using the R "phyper" function. The protein-protein interaction network of DEGs was built via the STRING. Target genes of differentially expressed miRNAs (DEmiRs) were predicted by miRanda. Furthermore, DEGs were selected as DEmiR targets and a DEmiR-DEG regulatory network was constructed via Cytoscape.

Results: In total, 3689 DEGs (such as opn1mw4, LOC103908930, si:dkeyp-1h4.8, crispld1b, cyp1a, and gdpd3a) including 2478 upregulated and 1211 downregulated genes were identified. 177 DEmiRs (such as dre-miR-96-3p, dre-miR-182-5p, dre-miR-9-7-3p, and dre-miR-124-4-5p) including 108 upregulated and 69 downregulated miRNAs were detected. The DEGs are involved in cell death, DNA repair, and cell development-related pathways. A protein-protein interaction network including 79 node genes was constructed to explore the interactions of DEGs. Furthermore, a DEmiR-DEG regulatory network focusing on the DNA repair process was constructed, including 21 hub DEGs and 15 hub DEmiRs.

Conclusions: We identified several DEGs and constructed a miRNA-mRNA regulatory network related to the DNA repair process in a zebrafish cataract model. These genes participate in the oxidative stress response of lens epithelium cells and finally contribute to the formation of zebrafish cataracts. The hub DEGs and hub DEmiRs could be potential therapeutic targets for ARC.