Integrated Analysis of tRNA-Derived Small RNAs in Proliferative Human Aortic Smooth Muscle Cells

Abstract

Background Abnormal proliferation of vascular smooth muscle cells (VSMCs) contributes to vascular remodeling diseases. Recently, it has been discovered that tRNA-derived small RNAs (tsRNAs), a new type of non-coding RNAs, are related to the proliferation and migration of VSMCs. tsRNAs regulate target gene expression through miRNA-like function. This study aims to explore the potential of tsRNAs in human aortic smooth muscle cell (HASMC) proliferation. Methods High-throughput sequencing was performed to analyze the tsRNA expression profile of proliferative and quiescent HASMCs. Quantitative real-time PCR (qRT-PCR) was performed to validate sequence results and subcellular distribution of AS-tDR-001370, AS-tDR-000067, AS-tDR-009512, and AS-tDR-000076. Based on microRNA-like functions of tsRNAs, we predicted target promoters, mRNAs, and circular RNAs (circRNAs), constructed tsRNA-promoter, tsRNA-mRNA, and circRNA-tsRNA interaction networks. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to reveal the function of target genes. Western blot and EdU incorporation assays were utilized to detect the effect of tsRNAs on HASMC proliferation. Results Compared with quiescent HASMCs, 887 up-regulated and 951 down-regulated tsRNAs in proliferative HASMCs were identified (fold change > 2 or < -2, p‑value < 0.05). AS-tDR-001370, AS-tDR-000067, AS-tDR-009512, and AS-tDR-000076 were up-regulated in proliferative HASMCs and were mainly located in the nucleus. Bioinformatics analysis suggested that they involve a variety of terms and pathways related to VSMC proliferation. Knockdown of AS-tDR-000067 promoted the expression of target gene p53 and inhibited HASMC proliferation. Knockdown of AS-tDR-000076 promoted the expression of target gene mitofusin 2 (MFN2) and inhibited HASMC proliferation. Conclusion During HASMC proliferation, the expression levels of many tsRNAs are altered. AS-tDR-000067 and AS-tDR-000076 may become a new therapeutic target for vascular remodeling diseases.