The Study Of Biological Roles And Mechanism Of Circ-TMEM165 In Endothelial Cells

Objective: Atherosclerosis is a chronic inflammatory vascular disease,and endothelial injury is one of the main initiation factors in the development of atherosclerosis.When endothelial dysfunction occured,it will cause leakage of the endothelial layer,resulted in a large amount of lipid infiltration,as well as macrophage infiltration.Therefore,maintaining the integrity of endothelial cells is the first barrier to protect vascular function.Circular RNA is a class of non-coding RNA molecules that do not have a 5’-cap and a 3’-poly(A)and form a closed circular structure with covalent bonds.Most of the circular RNAs are composed of exonic sequences,which are conserved in different species,with tissue and expression specificity at different developmental stages.Because the circular RNA is insensitive to nucleic acids,it is more stable than linear RNA,which makes the circular RNA have obvious advantages in the development and application of new clinical diagnostic markers.The study reported circ-TMEM165 was highly expressed in endothelial cells,and we speculate that it may have a potential association with endothelial function and atherosclerosis.Methods: In this study,we first collected atherosclerotic clinical tissue plaques and blood samples and detected circ-TMEM165 expression;subsequently,human umbilical vein endothelial cells were pathologically induced to detect circ-TMEM165 expression changes by qPCR;cell proliferation and migration were detected by circ-TMEM165 silencing and overexpression,respectively;CCK8 、 EdU and transwell and flow cytometry experiments were performed to evaluate cellular proliferation,invasion and apoptosis.The adhesion and inflammatory response of endothelial cells were verified by monocyte adhesion test and inflammatory factor test.Downstream targets of circ-TMEM165 were investigated by bioinformatics analysis,RNA immunoprecipitation and pull down assay.Finally,we constructed high-fat-induced atherosclerosis model and carotid balloon injury rats’ model,and treated with circ-TMEM165 nanocapsules to detect the role and mechanism of circ-TMEM165.Results: The results showed that the expression of circ-TMEM165 in atherosclerotic mouse model and carotid balloon injury rat model was significantly down-regulated.FISH assay found that circ-TMEM165 was localized in the nucleus and cytoplasm,while circ-TMEM165 could significantly inhibit the proliferation and migration of HUVECs and promote their apoptosis.Conclusion: Further studies have also exhibited that circ-TMEM165 potentially regulated its function in endothelial cells by mediating miRNA expression,thus inhibiting the occurrence and development of atherosclerosis.The above results suggested that circ-TMEM165 could be a potential clinical diagnostic marker and therapeutic target for atherosclerosis.This study provides a new direction for the treatment of atherosclerotic disease.