Association between gene variants and the recurrence of atrial fibrillation: An updated meta-analysis

Association between ZFHX3 and PRRX1 Polymorphisms and Atrial Fibrillation Susceptibility from Meta-Analysis

Background

Atrial fibrillation (AF) is a common, sustained cardiac arrhythmia. Recent studies have reported an association between ZFHX3/PRRX1 polymorphisms and AF. In this study, a meta-analysis was conducted to confirm these associations. Objective and Methods. The PubMed, Embase, and Wanfang databases were searched, covering all publications before July 20, 2020.

Results

Overall, seven articles including 3,674 cases and 8,990 healthy controls for ZFHX3 rs2106261 and 1045 cases and 1407 controls for PRRX1 rs3903239 were included. The odds ratio (OR) (95% confidence interval (CI)) was used to assess the associations. Publication bias was calculated using Egger's and Begg's tests. We found that the ZFHX3 rs2106261 polymorphism increased AF risk in Asians (for example, allelic contrast: OR [95% CI]: 1.39 [1.31–1.47], P < 0.001). Similarly, strong associations were detected through stratified analysis using source of control and genotype methods (for example, allelic contrast: OR [95% CI]: 1.51 [1.38–1.64], P < 0.001 for HB; OR [95% CI]: 1.31 [1.21–1.41], P < 0.001 for PB; OR [95% CI]: 1.55 [1.33–1.80], P < 0.001 for TaqMan; and OR [95% CI]: 1.31 [1.21–1.41], P < 0.001 for high-resolution melt). In contrast, an inverse relationship was observed between the PRRX1 rs3903239 polymorphism and AF risk (C-allele vs. T-allele: OR [95% CI]: 0.83 [0.77–0.99], P=0.036; CT vs. TT: OR [95% CI]: 0.79 [0.67–0.94], P=0.006). No obvious evidence of publication bias was observed.

Conclusions

In summary, our study suggests that the ZFHX3 rs2106261 and PRRX1 rs3903239 polymorphisms are associated with AF risk, and larger case-controls must be carried out to confirm the abovementioned conclusions.

Zfhx3 Transcription Factor Represses the Expression of SCN5A Gene and Decreases Sodium Current Density (INa)

The ZFHX3 and SCN5A genes encode the zinc finger homeobox 3 (Zfhx3) transcription factor (TF) and the human cardiac Na⁺ channel (Nav1.5), respectively. The effects of Zfhx3 on the expression of the Nav1.5 channel, and in cardiac excitability, are currently unknown. Additionally, we identified three Zfhx3 variants in probands diagnosed with familial atrial fibrillation (p.M1260T) and Brugada Syndrome (p.V949I and p.Q2564R). Here, we analyzed the effects of native (WT) and mutated Zfhx3 on Na⁺ current (I_Na) recorded in HL-1 cardiomyocytes. ZFHX3 mRNA can be detected in human atrial and ventricular samples. In HL-1 cardiomyocytes, transfection of Zfhx3 strongly reduced peak I_Na density, while the silencing of endogenous expression augmented it (from −65.9 ± 8.9 to −104.6 ± 10.8 pA/pF; n ≥ 8, p < 0.05). Zfhx3 significantly reduced the transcriptional activity of human SCN5A, PITX2, TBX5, and NKX25 minimal promoters. Consequently, the mRNA and/or protein expression levels of Nav1.5 and Tbx5 were diminished (n ≥ 6, p < 0.05). Zfhx3 also increased the expression of Nedd4-2 ubiquitin-protein ligase, enhancing Nav1.5 proteasomal degradation. p.V949I, p.M1260T, and p.Q2564R Zfhx3 produced similar effects on I_Na density and time- and voltage-dependent properties in WT. WT Zfhx3 inhibits I_Na as a result of a direct repressor effect on the SCN5A promoter, the modulation of Tbx5 increasing on the I_Na, and the increased expression of Nedd4-2. We propose that this TF participates in the control of cardiac excitability in human adult cardiac tissue.

Screening and functional analysis of differentially expressed lncRNAs in rapid atrial pacing dog atrial tissue

PURPOSE

Atrial fibrillation (AF) is one of the most commonly sustained arrhythmias in clinical practice. Long non-coding RNAs (lncRNAs) are gene regulatory elements involved in the development of several diseases. We aimed to explore the expression characteristics of lncRNAs associated with AF.

METHODS

We randomly assigned 12 adult healthy mongrel dogs into a control group and an atrial pacing group. Atrial pacing stimulation was performed at a high frequency of 500 beats per min for 14 consecutive days in the atrial pacing group. HE and Masson staining were used to detect rapid atrial pacing induced atrial fibrosis. Total RNA extraction was performed on dog atrial tissues and was used for high-throughput sequencing of lncRNAs.

RESULTS

A total of 10,310 lncRNAs were detected, and 33 differentially expressed lncRNAs were screened. Among them, 19 lncRNAs were upregulated in the atrial pacing group, and 14 lncRNAs were downregulated. Gene Ontology (GO) classification, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and interaction networks showed that AF-related lncRNAs participate in the regulation of AF in diverse biological processes, cellular components, molecular functions, signaling pathways, and complex interactions with miRNAs and mRNAs. Five differentially expressed lncRNAs were selected for RT-PCR validation, and the verification results were consistent with the results of lncRNA sequencing.

CONCLUSIONS

In summary, our study enhances our understanding of the biological functions of AF-related lncRNAs by screening and analyzing differentially expressed lncRNAs, and the results help to enrich the theoretical basis for the treatment of atrial fibrillation.