| Background and Objectives:Intimal hyperplasia(IH)is a structural change after vascular injury,and it is also a common pathological feature of restenosis after vascular reconstruction and atherosclerosis(AS).Vascular smooth muscle cells(VSMCs),as the main component of the vascular,play an important role in the process of IH.When vascular is injured,the VSMCs change from the contractile phenotype in the physiological state to the synthetic phenotype in the pathological state.With the increase of their proliferation,migration and secretion ability,the excessive proliferation and migration VSMCs and the secreted extracellular matrix accumulate in the vascular lumen and eventually form the neointima.Transfer RNA(tRNA)derived small RNA(tsRNA)is a new type of non-coding RNA(ncRNA)produced by the cleavage of tRNA under specific conditions.Recent studies have confirmed that tsRNA has the function of regulating gene expression and is involved in many diseases such as tumor,cardiovascular disease,immunity,infection and so on.However,the functional regulation and mechanism of tsRNA on VSMCs during IH are still unclear.Therefore,this study aims to explore whether tsRNA can participate in the development of IH by regulating VSMCs function and its mechanism.Research methods:Platelet-derived growth factor-BB(PDGF-BB)was used to induce the transformation of human aortic smooth muscle cells(HASMCs)from contractile to synthetic phenotype.The expression profiles of tsRNA in HASMCs with two different phenotypes were analyzed by tsRNA sequencing,and the significantly differentially expressed tsRNA were screened out and verified by qPCR.tiRNA-Gly-GCC was selected as the research target.qPCR was used to verify the expression trend of tiRNA-Gly-GCC in vascular tissues and plasma of AS patients and healthy controls,as well as in the rat carotid balloon injury model.Overexpression/knockdown of tiRNA-Gly-GCC in vitro was used to detect the changes in proliferation,migration,and phenotypic switching of HASMCs.Bioinformatics analysis was used to predict the target of tiRNA-Gly-GCC,and the interaction sites were verified by dual luciferase reporter gene.The target gene CBX3 was overexpressed by adenovirus for rescue experiments.To observe the effect of tiRNA-Gly-GCC knockdown on IH in a rat carotid balloon injury model and its mechanism.Results:Western blot results showed that the phenotypic transformation of HASMCs was successfully induced in vitro.The results of tsRNA sequencing showed that the expression profile of tsRNA was differentially expressed in HASMCs of the two phenotypes.QPCR experiments showed that tiRNA-Gly-GCC was significantly up-regulated and abundantly expressed in synthetic HASMCs.Further studies confirmed that tiRNA-Gly-GCC was upregulated in vascular tissues and plasma of AS patients and in injured carotid arteries of rats.CCK-8,EdU,western blot,cell scratch and transwell experiments showed that overexpression of tiRNA-Gly-GCC could promote the proliferation and migration and dedifferentiation of HASMCs.Knockdown of tiRNA-Gly-GCC could inhibit the proliferation,migration and reverse the synthetic phenotype of HASMCs.tiRNA-GlyGCC mainly regulates HASMCs function by targeting CBX3.Knockdown of tiRNA-GlyGCC in balloon-injured carotid arteries of rats can reverse the synthetic phenotype of VSMCs through CXB3 and finally inhibit IH.Conclusions:1.tiRNA-Gly-GCC is up-regulated in synthetic HASMCs,vascular tissues and plasma from AS patients,and balloon-injured carotid arteries in rats.2.tiRNA-Gly-GCC can promote the proliferation,migration and dedifferentiation of HASMCs.3.Knockdown of tiRNA-Gly-GCC inhibits the proliferation,migration and reverses the synthetic phenotype of HASMCs.4.CBX3 is the target of tiRNA-Gly-GCC in regulating the phenotypic transformation of HASMCs.5.Knockdown of tiRNA-Gly-GCC in vivo can reverse the synthetic phenotype of VSMCs by up-regulating CBX3,and finally inhibit the degree of IH after carotid balloon injury in rats. |
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