NAT10-Mediated ac4C Modification of IRF7 Promotes Diabetic Nephropathy Progression.

AIM: Diabetic nephropathy (DN) progression involves pyroptosis. Interferon regulatory factor 7 (IRF7) can regulate pyroptosis, but its role in DN is unknown. The RNA modifier N-acetyltransferase 10 (NAT10) catalyses N4-acetylcytidine (ac4C) and is linked to diabetic complications. This study tested whether NAT10-mediated ac4C modification of IRF7 mRNA exacerbates DN by promoting pyroptosis.

METHODS

The NAT10 expression levels in renal tissues from DN mice and in high-glucose (HG)-treated HK-2 cells were assessed by RT-qPCR and western blot. Cell viability, pyroptosis rate, levels of inflammatory cytokines (IL-1β, IL-18) and expression of pyroptosis-related proteins (NLRP3, cleaved caspase-1, GSDMD-N) were evaluated by CCK-8 assay, flow cytometry, ELISA and western blot, respectively. The interaction between NAT10 and IRF7 mRNA was investigated through bioinformatics prediction, RIP, acRIP-qPCR and actinomycin D chase assays. In vivo, an AAV-mediated shRNA targeting NAT10 was delivered to DN mice. Renal function, histopathology, tissue inflammation and protein expression were analysed using biochemical assays, HE staining, ELISA, immunohistochemistry and western blot.

RESULTS

NAT10 was upregulated in DN mice and HG-exposed HK-2 cells. Depletion of NAT10 inhibited HG-induced pyroptosis in HK-2 cells. Notably, NAT10 stabilized IRF7 through ac4C modification. Moreover, knockdown of NAT10 was found to alleviate HG-induced HK-2 cells' pyroptosis and DN in mice by downregulating IRF7 expression.

CONCLUSION

NAT10 upregulation promotes DN progression by enhancing IRF7 mRNA stability through ac4C modification, which provides new therapeutic targets for DN treatment.