Exploration Of Pathogenesis Of Degenerative Aortic Valvular Disease Based On Differential Expression Of CircRNAs

Objective:High throughput sequencing was used to identify the differentially expressed circRNAs in degenerative aortic valve and to analyze the possible molecular mechanism of circRNAs in the occurrence and development of degenerative aortic valvular disease.Methods:Aortic valve tissue was obtained from patients undergoing aortic valve replacement or heart transplantation.Some of the aortic valve tissues were retained for pathological classification and the rest were cryopreserved in liquid nitrogen for extraction of tissue RNA.The circRNA expression profiles of normal aortic valve tissue(normal group),fibrous calcified aortic valve tissue(fibrous calcification group)and myxoid aortic valve tissue(myxoid degeneration group)were detected by high throughput sequencing.The changes of circRNA expression between normal group and fibrous calcification group,normal group and mucoid degeneration group were analyzed,and the function enrichment analysis and pathway enrichment analysis of differentially expressed circRNAs were carried out.In addition,miRanda software was used to predict the miRNAs that circRNAs might bind to,and Targetscan database was used to predict the mRNAs interacting with miRNAs in order to explore the possible mechanism of differentially expressed circRNAs.Results:The pathological results showed that 15 aortic valves were sequenced by Illumina Hiseq 2500 next generation sequencing platform,including 6 cases of normal group,5 cases of fibrous calcification group and 4 cases of myxoid degeneration group.Compared with the normal group,243 differentially expressed circRNAs were found in the fibrous calcification group.Of them,196 were up-regulated(80.7%)and 47 were down-regulated(19.3%).In the functional enrichment results of differentially expressed circRNAs,the calcium-activated potassium channel activity was related with cardiac rhythm,and the endocytosis in the pathway enrichment results was related with the origin of valvular opening and closing ability.In the prediction of the most five significantly differential expression circRNAs' target miRNAs,miR-214-3p,miR-150-5p,miR-7-5p,miR-330-5p,miR-506-5p and miR-5003-3p were closely related to the endothelial-mesenchymal transformation.Compared with the normal group,229 of the 272 differentially expressed circRNAs were up-regulated(84.2%)and 43 of them were down-regulated(15.8%)in the myxoid degeneration group.In the functional enrichment and pathway enrichment results of differentially expressed circRNAs,the ubiquitin-mediated proteolysis was closely related to endothelial-mesenchymal transformation.In the prediction of the most five significantly differential expression circRNAs' target miRNAs,miR-542-3p,miR-150-5p,miR-4458 and miR-335-3p were involved in endothelial-mesenchymal transformation.Conclusion:The degenerative aortic valve presented differential circRNA expression.Differentially expressed circRNAs may play an important role in the occurrence and development of degenerative aortic valvular disease,especially in the process of endothelial-mesenchymal transformation.Differentially expressed circRNAs may inhibit the function of miRNAs through competitive inhibition,resulting in degenerative aortic valvular disease.