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

Abstract

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.