Inhibition Of Tirna-glygcc Ameliorates Neointimal Formation Via Cbx3-mediated Vascular Smooth Muscle Cells Phenotypic Switching

Introduction: Vascular smooth muscle cells (VSMCs) are the main component of blood vessels and synthetic VSMCs play an essential role in vascular diseases. tRNA-derived fragments (tRFs) are a new class of non-coding RNAs involved in a variety of pathological processes, but their biological functions and mechanisms in VSMCs phenotype transition and vascular intimal hyperplasia are unclear. Hypothesis: We assessed the hypothesis that tRFs play important role in VSMCs phenotype transition, regulation of tRFs could ameliorates neointimal formation. Methods: Differential expression profiles of tRFs from different phenotype of VSMCs was acquired using small-RNA sequence. The expression of tiRNA-Gly-GCC was confirmed in VSMCs, vascular tissues and plasma from healthy and atherosclerosis using quantitative real-time PCR and RNA fluorescence in situ hybridization. Gain-and loss- of function were performed using mimics and inhibitors to investigate the role of tiRNA-Gly-GCC in VSMCs phenotypic transition and neointimal formation after vascular injury. Dual-luciferase reporter gene and rescue experiments were performed to demonstrate the relationship between tiRNA-Gly-GCC and CBX3. Results: tiRNA-Gly-GCC is upregulated in synthetic VSMCs, atherosclerotic arteries, plasma and the balloon injured carotid artery of rats. Functionally, the inhibition of tiRNA-Gly-GCC represses VSMCs proliferation, migration, and reversed dedifferentiation, whereas the overexpression of tiRNA-Gly- GCC have contrary effects. Mechanistically, tiRNA-Gly-GCC performs these functions on VSMCs via downregulating the expression of CBX3. Finally, the inhibition of tiRNA-Gly-GCC could ameliorate neointimal formation after vascular injury in vivo . Conclusions: In conclusion, tiRNA-Gly-GCC is a mediator of VSMCs phenotypic switching by targeting CBX3, inhibition of tiRNA-Gly-GCC suppresses neointimal formation.