KLF3 aggravates renal fibrosis in chronic kidney disease through transcriptional activation of DDAH2

Renal fibrosis is recognized as a critical pathway leading to end-stage renal disease in nearly all cases of chronic kidney disease (CKD). Analysis of the gene expression omnibus (GEO) database revealed that the transcription factor Krüppel-like factor 3 (KLF3) was elevated in kidney tissues of CKD patients, however, its specific role in CKD-associated renal fibrosis is yet to be deciphered. This study aimed to investigate the function of KLF3 on unilateral ureteral obstruction (UUO) mice and transforming growth factor-β1 (TGF-β1)-stimulated HK2 cells. Our data demonstrated that KLF3 was remarkably upregulated in the renal cortex of UUO mice and TGF-β1-treated HK-2 cells. We further confirmed that the upregulation of KLF3 was associated with its N6-methyladenosine (m6A) methylation modification. Knockdown of METTL14 reduced m6A methylation level of KLF3 and inhibited its mRNA stability. In vivo results suggested that KLF3 knockdown alleviated the pathological changes in renal tissues triggered by UUO. Additionally, KLF3 silencing mitigated renal fibrosis both in vivo and in vitro , as accompanied by decreased expression of Collagen I, Vimentin, α-SMA and Fibronectin. Mechanistically, KLF3 transcription activated dimethylarginine dimethylaminohydroxylase 2 (DDAH2) and upregulated its expression. Rescue experiments substantiated that DDAH2 overexpression eliminated the effect of KLF3 knockdown on renal fibrosis. Collectively, our findings suggest that inhibition of KLF3 may serve as a potential strategy to prevent CKD-associated renal fibrosis.