RBM15 Promotes High Glucose-Induced Lens Epithelial Cell Injury by Inducing PRNP N6-Methyladenine Modification During Diabetic Cataract.

Purpose: Diabetic cataract (DC) is a major cause of blindness worldwide. Prion protein (PRNP) was proved to be up-regulated and hypomethylated in DC samples. Here, we investigated whether PRNP was involved in DC progression in N6-methyladenosine (m6A)-dependent manner, and its potential mechanisms.

Methods: Levels of genes and proteins were assayed using qRT-PCR and western blotting. Cell proliferation and apoptosis were determined using Cell Counting Kit-8 assay, 5-thynyl-2'-deoxyuridine (EdU) assay, and flow cytometry, respectively. Oxidative stress was analyzed by measuring the production of glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), and malondialdehyde (MDA). The m6A modification was determined by RNA immunoprecipitation (Me-RIP) assay. The interaction between RBM15 (RNA binding motif protein 15) and PRNP was probed using RIP assay.

Results: PRNP was highly expressed in DC patients and HG-induced HLECs. Functionally, PRNP deficiency reversed HG-induced apoptosis and oxidative stress in HLECs. Mechanistically, RBM15 induced PRNP m6A modification and directly bound to PRNP. Knockdown of RBM15 abolished HG-induced apoptotic and oxidative injury in HLECs, while these effects were rescued after PRNP overexpression.

Conclusion: RBM15 silencing suppressed HG-induced lens epithelial cell injury by regulating PRNP in an m6A-mediated manner, hinting a novel therapeutic strategy for DC patients.