CircRNA_0079586 and circRNA_RanGAP1 are involved in the pathogenesis of intracranial aneurysms rupture by regulating the expression of MPO

Several circRNAs have been reported to be dysregulated in human endothelial cells through sponging miRNAs. Previous reports demonstrated that MPO not only contributed to the formation and rupture of cerebral aneurysm but was also correlated with the degenerative remodeling predisposition to saccular intracranial aneurysm wall rupture, although its underlying mechanisms remain to be explored. Microarray screening was performed to compare the differential expression of circRNAs in the endothelial cells collected from UIAs and RIAs patients. Luciferase assays were used to explore the regulatory relationship between circRNAs and miRNAs, and between miRNAs and their target genes. Microarray screening analysis found a batch of up-regulated circRNAs in the endothelial cells harvested from RIAs patients, including circRNA-0079586 and circRNA-RanGAP1. Luciferase assays revealed the suppressive role of miR-183-5p/miR-877-3p in the expression of circRNA-0079586/circRNA-RanGAP1/MPO. And the expression of circRNA-0079586 and circRNA-RanGAP1 was respectively suppressed by the overexpression of miR-183-5p and miR-877-3p. And both the transfection of miR-183-5p and miR-877-3p mimics suppressed the relative expression level of MPO mRNA. The expression of circRNA-0079586, circRNA-RanGAP1 and MPO was significantly activated in the endothelial cells collected from RIAs patients when compared with UIAs patients, whereas the expression of miR-183-5p and miR-877-3p was remarkably suppressed in the endothelial cells collected from RIAs patients when compared with UIAs patients. We further altered the expression of circRNA-0079586 and circRNA-RanGAP1 using siRNA and overexpression in HUVECS, and the expression of circRNA-0079586 and circRNA-RanGAP1 was significantly and negatively correlated with the expression of miR-183-5p and miR-877-3p, but positively correlated with the expression of MPO under different conditions. In this study, we established two MPO-modulating signaling pathways of circRNA_0079586/miR-183-5p/MPO and circRNA_RanGAP1/miR-877-3p/MPO. These two signaling pathways are involved in the pathogenesis of intracranial aneurysms rupture.