tRF-1-ArgTCG-1-1 promotes renal fibrosis by regulating β-catenin

Renal fibrosis (RF) is a crucial pathological factor in the progression of chronic kidney disease (CKD) to end-stage renal failure. The role of noncoding RNAs (ncRNAs) in CKD has been researched recently. tRNA-derived fragments (tRFs) constitute a class of small ncRNAs originating from tRNAs. To date, the function of tRFs in RF remains unexplored.

Human small RNA microarray analysis was performed to identify dysregulated tRFs in urine-derived renal tubular epithelial cells from patients with RF. RT-PCR was used for validation in clinical samples. Hydroxylamine-mediated protein precipitation mass spectrometry (Hypro-MS), parallel reaction monitoring (PRM), and antisense oligonucleotide (ASO)-mediated knockdown were used to investigate the interaction between tRF-1-ArgTCG-1-1 and β-catenin and its functional role in TGF-β1-treated HK-2 cells.

Microarray profiling identified tRF-1-ArgTCG-1-1 as an upregulated tRF in urine-derived renal tubular epithelial cells from patients with RF. RT-PCR further confirmed that tRF-1-ArgTCG-1-1 expression was significantly increased in urine samples from patients with CKD and was associated with impaired renal function and a higher risk of RF. Hypro-MS and PRM analyses demonstrated an interaction between tRF-1-ArgTCG-1-1 and β-catenin. ASO-mediated silencing of tRF-1-ArgTCG-1-1 reduced β-catenin expression in HK-2 cells. Moreover, silencing of tRF-1-ArgTCG-1-1, alone or together with β-catenin, attenuated TGF-β1-induced expression of RF-related markers in vitro.

Overall, these findings suggest that renal tubular epithelial cells tRF-1-ArgTCG-1-1 play a key role in RF and that the tRF-1-ArgTCG-1-1/β-catenin pathway is a potential therapeutic target for CKD and RF.