Identifying Circ-RNF216 as a Regulator of Renal Tubular Epithelial Cell Proliferation Via the TGF-Β1/Smad3-Mediated Pathway in Chronic Kidney Disease.

BACKGROUND/AIMS: Emerging evidence suggests that circular RNAs (circRNAs) play a crucial role in kidney disease regulation. However, their functional significance in chronic kidney disease (CKD) remains poorly understood.

METHODS

In this study, circRNAs were identified by RNA sequencing in two CKD mouse models, including unilateral ureteral obstruction (UUO) and anti-glomerular basement membrane (anti-GBM) glomerulonephritis. RNase-R treatment and Sanger sequencing were used to confirm circular structure. Circ-RNF216-shRNA was used to establish stable knockdown mTEC cell lines. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect circ-RNF216 expression. In situ hybridization was used to assess the expression and localization of circ-RNF216 in kidney. Transwell assays were performed to assess cell migration. RNA sequencing was performed to characterize mRNA expression profiles and identify pathways affected by circ-RNF216 knockdown in mTECs.

RESULTS

We identified 1,589 circRNAs in two CKD mouse models. Circ-RNF216 expression was up-regulated in UUO models. Functional analyses revealed that circ-RNF216 regulates renal fibrosis through modulation of the TGF-β1/Smad3 pathway. Knocking down circ-RNF216 in mouse tubular epithelial cells led to significant suppression of migratory capacity and fibrosis. RNA sequencing showed that circ-RNF216 knockdown altered mRNA expression, with differentially expressed genes mainly enriched in the transforming growth factor-β receptor superfamily signaling pathway.

CONCLUSION

Our findings highlight circ-RNF216 as a novel regulatory factor in CKD-related renal fibrosis, broadening our understanding of circRNA involvement in kidney disease pathogenesis and suggesting circ-RNF216 as a potential therapeutic target for preserving renal function.