Expression Profiles of Circular RNA in Aortic Vascular Tissues of Spontaneously Hypertensive Rats.

Background: Circular RNAs (circRNAs), as a kind of endogenous non-coding RNA, have been implicated in ischemic heart diseases and vascular diseases. Based on theirs high stability with a closed loop structure, circRNAs function as a sponge and bind specific miRNAs to exert inhibitory effects in heart and vasculature, thereby regulating their target gene and protein expression, via competitive endogenous RNA (ceRNA) mechanism. However, the exact roles and underlying mechanisms of circRNAs in hypertension and related cardiovascular diseases remain largely unknown. Methods and Results: High-throughput RNA sequencing (RNA-seq) was used to analyze the differentially expressed (DE) circRNAs in aortic vascular tissues of spontaneously hypertensive rats (SHR). Compared with the Wistar-Kyoto (WKY) rats, there were marked increases in the levels of systolic blood pressure, diastolic blood pressure and mean blood pressure in SHR under awake conditions via the tail-cuff methodology. Totally, compared with WKY rats, 485 DE circRNAs were found in aortic vascular tissues of SHR with 279 up-regulated circRNAs and 206 down-regulated circRNAs. Furthermore, circRNA-target microRNAs (miRNAs) and the target messenger RNAs (mRNAs) of miRNAs were predicted by the miRanda and Targetscan softwares, respectively. Additionally, real-time RT-PCR analysis verified that downregulation of rno_circRNA_0009197, and upregulation of rno_circRNA_0005818, rno_circRNA_0005304, rno_circRNA_0005506, and rno_circRNA_0009301 were observed in aorta of SHR when compared with that of WKY rats. Then, the potential ceRNA regulatory mechanism was constructed via integrating 5 validated circRNAs, 31 predicted miRNAs, and 266 target mRNAs. More importantly, three hub genes (NOTCH1, FOXO3, and STAT3) were recognized according to PPI network and three promising circRNA-miRNA-mRNA regulatory axes were found in hypertensive rat aorta, including rno_circRNA_0005818/miR-615/NOTCH1, rno_circRNA_0009197/ miR-509-5p/FOXO3, and rno_circRNA_0005818/miR-10b-5p/STAT3, respectively. Conclusions: Our results demonstrated for the first time that circRNAs are expressed aberrantly in aortic vascular tissues of hypertensive rats and may serve as a sponge linking with relevant miRNAs participating in pathogenesis of hypertension and related ischemic heart diseases via the circRNA-miRNA-mRNA ceRNAnetwork mechanism.

Liu Y ，Dong Y ，Dong Z ，Song J ，Zhang Z ，Liang L ，Liu X ，Sun L ，Li X ，Zhang M ，Chen Y ，Miao R ，Zhong J ... -  《Frontiers in Cardiovascular Medicine》

Construction of endogenous RNA regulatory network for colorectal cancer based on bioinformatics.

Li Y ，Yuan F ，Lin Z ，Pan Y ... -  《-》

Construction of the circRNA-miRNA-mRNA Regulatory Network of an Abdominal Aortic Aneurysm to Explore Its Potential Pathogenesis.

Abdominal aortic aneurysm (AAA) is a progressive cardiovascular disease, which is a permanent and localized dilatation of the abdominal aorta with potentially fatal consequence of aortic rupture. Dysregulation of circRNAs is correlated with the development of various pathological events in cardiovascular diseases. However, the function of circRNAs in abdominal aortic aneurysm (AAA) is unknown and remains to be explored. This study is aimed at determining the regulatory mechanisms of circRNAs in AAAs. This study was aimed at exploring the underlying molecular mechanisms of abdominal aortic aneurysms based on the competing endogenous RNA (ceRNA) regulatory hypothesis of circRNA, miRNA, and mRNA. The expression profiles of circRNAs (GSE144431), miRNAs (GSE62179), and mRNAs (GSE7084, GSE57691, and GSE47472) in human tissue sample from the aneurysm group and normal group were obtained from the Gene Expression Omnibus database, respectively. The circRNA-miRNA-mRNA network was constructed by using Cytoscape 3.7.2 software; then, the protein-protein interaction (PPI) network was constructed by using the STRING database, and the hub genes were identified by using the cytoHubba plug-in. The circRNA-miRNA-hub gene regulatory subnetwork was formed to understand the regulatory axis of hub genes in AAAs. The present study identified 40 differentially expressed circRNAs (DECs) in the GSE144431, 90 differentially expressed miRNAs (DEmiRs) in the GSE62179, and 168 differentially expressed mRNAs (DEGs) with the same direction regulation (130 downregulated and 38 upregulated) in the GSE7084, GSE57691, and GSE47472 datasets identified regarding AAAs. The miRNA response elements (MREs) of three DECs were then predicted. Four overlapping miRNAs were obtained by intersecting the predicted miRNA and DEmiRs. Then, 17 overlapping mRNAs were obtained by intersecting the predicted target mRNAs of 4 miRNAs with 168 DEGs. Furthermore, the circRNA-miRNA-mRNA network was constructed through 3 circRNAs, 4 miRNAs, and 17 mRNAs, and three hub genes (SOD2, CCR7, and PGRMC1) were identified. Simultaneously, functional enrichment and pathway analysis were performed within genes in the circRNA-miRNA-mRNA network. Three of them (SOD2, CCR7, and PGRMC1) were suggested to be crucial based on functional enrichment, protein-protein interaction, and ceRNA network analysis. Furthermore, the expression of SOD2 and CCR7 may be regulated by hsa_circ_0011449/hsa_circ_0081968/hsa-let-7f-5p; the expression of PGRMC1 may be regulated by hsa_circ_0011449/hsa_circ_0081968-hsa-let-7f-5p/hsa-let-7e-5p. In conclusion, the ceRNA interaction axis we identified may be an important target for the treatment of abdominal aortic aneurysms. This study provided further understanding of the potential pathogenesis from the perspective of the circRNA-related competitive endogenous RNA network in AAAs.

Zhang H ，Bian C ，Tu S ，Yin F ，Guo P ，Zhang J ，Wu Y ，Yin Y ，Guo J ，Han Y ... -  《-》

CircRNA and miRNA expression profiles during remote ischemic postconditioning attenuate brain ischemia/reperfusion injury.

Remote ischemic postconditioning (RIPostC) is a protective procedure for brain damage caused by ischemia/reperfusion (IR), yet the mechanism of this treatment remains to be elucidated. Circular RNAs (circRNAs) are endogenous non-coding RNAs that have recently been recognized to play vital roles in ischemic brain injury. The aim of this study was to explore the role of circRNAs in the protective mechanism of RIPostC and to analyze the circRNA-microRNA (miRNA) regulation network in RIPostC. Nine rats were assigned randomly into three groups (three rats per group): sham, IR, and RIPostC. Their brain tissues were extracted for next-generation RNA sequencing and bioinformatics analysis was performed for two comparisons: sham vs. IR and IR vs. RIPostC. The expression patterns of selected circRNAs and miRNAs were validated by quantitative real-time PCR (qPCR). We detected 82 upregulated and 51 downregulated circRNAs and 137 upregulated and 127 downregulated miRNAs in the IR group compared with the sham group, and 41 upregulated and 100 downregulated circRNAs and 45 upregulated and 64 downregulated miRNAs in the RIPostC group compared with the IR group. The proposed competitive endogenous RNA (ceRNA) network, which included 24 circRNAs, 20 miRNAs, and 145 mRNAs, indicated that the dysregulated circRNAs played important roles in brain IR injury. On the basis of the expression patterns of selected circRNAs, miRNAs, and mRNAs obtained by qPCR, we proposed a circRNA_0002286-miR-124-3p-VLCAD pathway. In PC12 cell, the expression level of miR-124-3p was significantly upregulated when the expression of circRNA_0002286 was repressed and the expression level of VLCAD (very-long chain acyl-CoA dehydrogenase) was significantly downregulated, which suggested that circRNA_0002286 may act as a miRNA sponge for miR-124-3p to regulate the expression of VLCAD. We found that upregulation of circRNA_0002286 attenuated IR injury and was associated with downregulation of miR-124-3p and upregulation of VLCAD. This is the first time that circRNAs have been shown to be closely related to brain IR injury and RIPostC and suggests that targeting the circRNA_0002286-miR-124-3p-VLCAD pathway might attenuate brain IR injury.

Li CY ，Ma W ，Liu KP ，Yang JW ，Wang XB ，Wu Z ，Zhang T ，Wang JW ，Liu W ，Liu J ，Liang Y ，Zhang XK ，Li JJ ，Guo JH ，Li LY ... -  《-》

Analysis and verification of the circRNA regulatory network RNO_CIRCpedia_ 4214/RNO-miR-667-5p/Msr1 axis as a potential ceRNA promoting macrophage M2-like polarization in spinal cord injury.

CircRNAs are involved in the pathogenesis of several central nervous system diseases. However, their functions and mechanisms in spinal cord injury (SCI) are still unclear. Therefore, the purpose of this study was to evaluate circRNA and mRNA expression profiles in the pathological setting of SCI and to predict the potential function of circRNA through bioinformatics. A microarray-based approach was used for the simultaneous measurement of circRNAs and mRNAs, together with qPCR, fluorescence in situ hybridization, western immunoblotting, and dual-luciferase reporter assays to investigate the associated regulatory mechanisms in a rat SCI model. SCI was found to be associated with the differential expression of 414 and 5337 circRNAs and mRNAs, respectively. Pathway enrichment analyses were used to predict the primary function of these circRNAs and mRNAs. GSEA analysis showed that differentially expressed mRNAs were primarily associated with inflammatory immune response activity. Further screening of these inflammation-associated genes was used to construct and analyze a competing endogenous RNA network. RNO_CIRCpedia_4214 was knocked down in vitro, resulting in reduced expression of Msr1, while the expression of RNO-miR-667-5p and Arg1 was increased. Dual-luciferase assays demonstrated that RNO_CIRCpedia_4214 bound to RNO-miR-667-5p. The RNO_CIRCpedia_4214/RNO-miR-667-5p/Msr1 axis may be a potential ceRNA that promotes macrophage M2-like polarization in SCI. Overall, these results highlighted the critical role that circRNAs may play in the pathophysiology of SCI and the discovery of a potential ceRNA mechanism based on novel circRNAs that regulates macrophage polarization, providing new targets for the treatment of SCI.

Cao J ，Pan C ，Zhang J ，Chen Q ，Li T ，He D ，Cheng X ... -  《BMC GENOMICS》