Identification and characterization of circular RNAs in atrial appendage of patients with atrial fibrillation.

Circular RNAs (circRNAs) have emerged as a novel type of non-coding RNA (ncRNA) of interest in gene regulation, especially for its vital function underlying many diseases. Atrial fibrillation is the most common sustained arrythmia. However, the expression spectrum and function of circRNAs in atrial appendage of patients with atrial fibrillation (AF) has seldomly been investigated. Human atrial appendage tissues were acquired during cardiac surgery, which were divided into the AF group and the Sinus rhythm (SR) group. The expression characterization of circRNAs of two groups was revealed by high-throughput sequencing. The dysregulated circRNAs were identified and analyzed by bioinformatics methods, and further validated by realtime PCR. A total 18109 circRNAs in human atrial appendage tissues were targeted. Among them, 147 differentially expressed circRNAs (102 up-regulated and 45 down-regulated) were found between AF group and SR group. Gene ontology (GO) and KEGG pathway analysis indicated that many mRNAs transcribed from the host genes of altered circRNAs were implicated in regulation of sequence-specific DNA binding transcription factor activity, as well as nicotinate and nicotinamide metabolism pathways. Analysis of the association between differently expressed circRNA and miRNA were explored, which revealed an ample interaction. Our study firstly revealed the expression spectrum of circRNAs in both left and right atrial appendage of patients with or without AF. Differentially expressed circRNAs in the atrial appendage were also identified, analyzed and validated. The results of this study may provide novel biomarkers and potential therapeutic targets for AF.

Zhang Y ，Shen H ，Wang P ，Min J ，Yu Y ，Wang Q ，Wang S ，Xi W ，Nguyen QM ，Xiao J ，Wang Z ... -  《-》

Identification of atrial fibrillation-related circular RNAs and constructing the integrative regulatory network of circular RNAs, microRNAs and mRNAs by bioinformatics analysis.

Zhai Z ，Qin T ，Liu F ，Han L ，Zhou H ，Li Q ，Xia Z ，Li J ... -  《-》

Genome-wide profiling reveals atrial fibrillation-related circular RNAs in atrial appendages.

Atrial fibrillation (AF) is an abnormal heart rhythm characterized by rapid and irregular beating of the atria. The non-coding RNAs (ncRNAs) have attracted much attention of AF researchers, as they play a critical role in the transcriptional and post-transcriptional regulation, which could greatly benefit the interpretation of the pathogenesis of AF. However, circRNAs, as a special member of the ncRNAs, and their role in the pathogenesis of AF is less understood. In the present study, we detected a total of 14,215 circRNAs in AF patients and healthy controls. Differential expression analysis of these circRNAs revealed 20 upregulated and 3 downregulated circRNAs, which were differentially expressed in both left and right atrial appendages. The association analysis of the AF-related circRNAs and their parental genes revealed that hsa_circ_0003965 had significantly negative correlation with its parental gene TMEM245 (PCC = -0.51), suggesting that the dysregulation of hsa_circ_0003965 was not regulated by the transcription of its parental gene, but could be associated with glucagon signaling pathway. The competing endogenous RNA (ceRNA) network analysis revealed two upregulated genes, IFNG and GDF7, and one downregulated gene, BMP7, all of which were involved in TGF-beta signaling pathway, which further suggested that these circRNAs, namely hsa_circ_0000075 and hsa_circ_0082096, participated in the AF pathogenesis via TGF-beta signaling pathway. Consistently, TGF-beta signaling pathway was a well-recognized player for its association with atrial fibrosis in AF. In summary, we aimed to discover and provide key circRNAs involved in AF for AF-related researchers, which had the potential to greatly improve our understanding of the underlying mechanism behind circRNAs and AF.

Zhang PP ，Sun J ，Li W 《-》

Identification and characterization of circular RNAs in rapid atrial pacing dog atrial tissue.

Circular RNAs (circRNAs) have emerged as novel molecules of interest in gene regulation as other noncoding RNAs, and participating in the process of many diseases. However, the expression and functions of circRNAs in Rapid atrial pacing (RAP) dog atrial tissue still unknown. 12 canines were randomly assigned to control and pacing group. RAP at 500 beats per minute was maintained 14 days in the pacing group. The expression characterization of circRNAs were revealed by high-throughput sequencing. We totally predicted 15,990 circRNAs in dog atrial tissues. Moreover, we found 146 differentially expressed circRNAs between control and RAP dogs. Five circRNAs were selected for subsequent RT-PCR validation, and four circRNAs confirmed with the high throughput sequencing analysis. GO analysis showed that the differentially expressed circRNAs might involve in the process of "structural constituent of cytoskeleton, ion channel activity". We explored the circRNA-miRNA interaction network, and found extensive interaction among differentially expressed circRNAs and AF related miRNAs and mRNAs. Our work firstly identified the characterization of circRNAs in the dog atrial, and revealed the differentially expressed circRNAs in the RAP dog, this might lay a solid foundation on the function of circRNA in the mechanisms of AF.

Shangguan W ，Liang X ，Shi W ，Liu T ，Wang M ，Li G ... -  《-》

Characterization of circRNA‑associated ceRNA networks in patients with nonvalvular persistent atrial fibrillation.

Zhang Y ，Ke X ，Liu J ，Ma X ，Liu Y ，Liang D ，Wang L ，Guo C ，Luo Y ... -  《-》