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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.