NSUN3 Aggravates Sepsis-Associated Acute Kidney Injury by Stabilising TIFA mRNA Through m5C

Acute kidney injury (AKI) is a common complication of sepsis and also a risk factor for progression of chronic kidney disease. NOP2/Sun RNA methyltransferase 3 (NSUN3) is involved in the regulation of sepsis progression. However, the mechanism by which NSUN3 regulates sepsis-associated AKI (SA-AKI) remains unclear.

SA-AKI mouse model and lipopolysaccharide (LPS)-induced injury model in HK-2 cells were constructed. Haematoxylin-eosin staining, quantitative polymerase chain reaction (qPCR), western blotting, cell counting kit 8, flow cytometry, 2',7'-dichlorofluorescein diacetate, enzyme-linked immunosorbent assay, methylation RNA immunoprecipitation-qPCR, actinomycin D and TdT-mediated dUTP Nick-End Labelling staining assays were utilised to explore the expression and related mechanism of NSUN3 in the SA-AKI models.

The expression of NSUN3 and tumour necrosis factor receptor-associated factor (TRAF)-interacting protein with forkhead-associated domain (TIFA) was upregulated in mice with SA-AKI and LPS-induced HK-2 cells. Knockdown of NSUN3 inhibited LPS-induced injury in HK-2 cells. Mechanically, NSUN3 increased TIFA mRNA stability and upregulated its expression through m5C modification. Moreover, knockdown of NSUN3 was found to alleviate LPS-induced HK-2 cell injury and SA-AKI in mice by reducing TIFA expression.

NSUN3 aggravates SA-AKI by stabilising TIFA mRNA through m5C, indicating that NSUN3 may be a biomarker for SA-AKI.