MULTIPLE SCN5A ENHANCERS MODULATE CARDIAC GENE EXPRESSION AND QT INTERVAL VARIATION
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ABSTRACT:
PROVIDER: PRJNA431786 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR6514810_1.fastq.gz | Fastqsanger.gz | |||
| SRR6514810_2.fastq.gz | Fastqsanger.gz | |||
| SRR6514811_1.fastq.gz | Fastqsanger.gz | |||
| SRR6514811_2.fastq.gz | Fastqsanger.gz | |||
| SRR6514812_1.fastq.gz | Fastqsanger.gz |
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Project description:Genome-wide association studies (GWAS) have suggested that sequence variation in cis-regulatory elements (CREs) modulate common disease risk and trait variation. However, identification of the majority of these causal variants and their mechanism of action have remained significant challenges. We used reporter assays for all common variants at the QT interval associated SCN5A GWAS locus with the goal of identifying causal variants for the association. A target region of ~500kb containing SCN5A was defined based on recombination hotspots (rate>10cM/Mb; estimated from HapMap) flanking the 5 independent QT interval GWAS hits. Within this region, all common variants (minor allele frequency >5%), from the 1000 Genomes European ancestry populations, in moderate linkage disequilibrium (LD; r2>0.3) with any of the 5 sentinel hits, were selected for analyses. Of a total 121 variants selected, 112 variants in 104 amplicons passed primer design (amplicon size 256-617bp; median 397bp), with both alleles of 106 variants successfully cloned along with flanking sequences into 98 amplicons upstream of a minimal promoter-driven firefly luciferase gene in pGL4.23. Cardiomyocyte cells, AC16 (human) and HL1 (mouse), were transfected with test constructs and Renilla luciferase vector (for transfection normalization) in triplicate; luciferase assays were performed 24h later. All cloning and reporter assays were performed in 96- and 24-well plates. In reporter assays across the two cell lines, compared to empty vector, 37 amplicons showed enhancer activity (z-score>99 %tile), with a concordance rate of ~70%. Of these 37 enhancer CREs, 9 overlapped open chromatin regions (DNase-seq peaks) observed in adult human heart tissue, largest among all human tissues evaluated by the RoadMap Epigenomics project. Of these 37 enhancer CREs, 12 showed allelic difference in reporter activity (P<0.05), thus identifying at least one enhancer CRE variant in high-to-moderate LD with each of the 5 sentinel hits. Using GTEx heart left ventricle (n=190) gene expression data, we showed correlation between SCN5A expression and the number of QT interval prolonging alleles across the 5 index SNPs. We are currently assessing the binding of cardiac nuclear factors at the 12 enhancer CRE variants by gel-shift assays and the effect of CRISPR-Cas9 mediated CRE deletion on SCN5A expression in AC16 and HL1 cells, an analyses helped by evaluation of AC16 and HL1 cells by RNA-seq, ATAC-seq and karyotyping. Thus, independent of the publicly available epigenomic data, which are of limited cell-type relevance, an unbiased in vitro reporter screen for CREs overlapping all common variants associated with QT interval at the SCN5A GWAS locus identified 12 common cis-regulatory variants that map to cardiac open chromatin regions and correlate with SCN5A cardiac expression.
2019-04-22 | GSE109716 | GEO
Project description:Our goal is to identify high-confidence candidate genes associated with sub-threshold QT interval loci. We predicted enhancer-promoter targets using two different methods.
2014-10-10 | GSE53567 | GEO
Project description:Prolonged electrocardiographic indices reflecting myocardial impulse conduction and repolarization are risk factors for sudden cardiac death and drug-induced arrhythmia. The PR-interval, QRS-duration and QT-interval are heritable traits influenced by multiple genetic and environmental factors. The genetic underpinnings of these traits are still largely unknown. In this study, we leveraged the variability in cardiac gene expression and the variation in PR-, QRS- and QT-intervals among F2 mice harboring the cardiac sodium ion-channel mutation Scn5a-1798insD/+ derived from the 129P2-Scn5a1798insD/+ and FVB/NJ-Scn5a1798insD/+ cross, to isolate novel genes and biological pathways impacting on cardiac conduction and repolarization. Cardiac left-ventricle total RNA from 120 F2-(129P2xFVBN/J)-Scn5a-1798insD/+ mice at 12 to 14 weeks old.
2012-12-01 | E-GEOD-27236 | biostudies-arrayexpress
Project description:Our goal is to identify high-confidence candidate genes associated with sub-threshold QT interval loci. We predicted enhancer-promoter targets using two different methods. 1) We used the correlation in activity between enhancers and transcribed genes across 59 human cell lines and tissues to identify significantly correlated enhancer-promoter pairs that represent potential regulatory interactions. 2) We used chromosome conformation capture followed by high-throughput sequencing (4C-seq) to probe physical enhancer-promoter interactions.
2014-10-10 | E-GEOD-53567 | biostudies-arrayexpress
Project description:Prolonged electrocardiographic indices reflecting myocardial impulse conduction and repolarization are risk factors for sudden cardiac death and drug-induced arrhythmia. The PR-interval, QRS-duration and QT-interval are heritable traits influenced by multiple genetic and environmental factors. The genetic underpinnings of these traits are still largely unknown. In this study, we leveraged the variability in cardiac gene expression and the variation in PR-, QRS- and QT-intervals among F2 mice harboring the cardiac sodium ion-channel mutation Scn5a-1798insD/+ derived from the 129P2-Scn5a1798insD/+ and FVB/NJ-Scn5a1798insD/+ cross, to isolate novel genes and biological pathways impacting on cardiac conduction and repolarization.
2012-12-01 | GSE27236 | GEO
Project description:The rationale for genome-wide association study (GWAS) results is sequence variation in cis-regulatory elements (CREs) modulating a target gene's expression as the major cause of trait variation. To understand the complete molecular landscape of one of these GWAS loci, we performed in vitro reporter screens in cardiomyocyte cell lines for CREs overlapping nearly all common variants associated with any of five independent QT interval (QTi)-associated GWAS hits at the SCN5A-SCN10A locus. We identified 13 causal CRE variants using allelic reporter activity, cardiomyocyte nuclear extract-based binding assays, overlap with human cardiac tissue DNaseI hypersensitive regions, and predicted impact of sequence variants on DNaseI sensitivity. Our analyses identified at least one high-confidence causal CRE variant for each of the five sentinel hits that could collectively predict SCN5A cardiac gene expression and QTi association. Although all 13 variants could explain SCN5A gene expression, the highest statistical significance was obtained with seven variants (inclusive of the five above). Thus, multiple, causal, mutually associated CRE variants can underlie GWAS signals.
| S-EPMC6561183 | biostudies-literature
Project description:Several empirical and theoretical studies suggest the presence of multiple enhancers per gene that collectively regulate gene expression, and that common sequence variation impacting on the activities of these enhancers is a major source of inter-individual gene expression variability. However, for the vast majority of genes, enhancers and the underlying regulatory variation remains unknown. Even for the genes with well-characterized enhancers, the nature of the combined effects from multiple enhancers and their variants, when known, on gene expression regulation remains unexplored. Here, we have evaluated the combined effects from five SCN5A enhancers and their regulatory variants that are known to collectively correlate with SCN5A cardiac expression and underlie QT interval association in the general population. Using small deletions centered at the regulatory variants in episomal reporter assays in a mouse cardiomyocyte cell line, we demonstrate that the variants and their flanking sequences play critical role in individual enhancer activities, likely being a transcription factor (TF) binding site. By oligonucleotide-based pulldown assays on predicted TFs, we identify the TFs likely driving allele-specific enhancer activities. Using all 32 possible allelic synthetic constructs in reporter assays, representing the five bi-allelic enhancers, we demonstrate combined additive effects on overall enhancer activities. Using transient enhancer assays in zebrafish embryos we demonstrate that four elements act as enhancers in vivo. Together, these studies uncover the TFs driving the enhancer activities of QT interval associated SCN5A regulatory variants, reveal the additive effects from allelic combinations of these regulatory variants, and prove their potential to act as enhancers in vivo.
| S-EPMC11532988 | biostudies-literature
Project description:SCN5A was reported to promote proliferation and invasiveness potential in colorectal cancer, yet the mechanism was not clarified, and little was known about its association with chemosensitivity to 5-fluorouracil. In the current study, elevated SCN5A expression were associated with poor prognosis and metastasis in colorectal cancers, whereas stage II-III patients with up-regulated SCN5A expression were more likely to benefit from 5-fluorouracil-based adjuvant chemotherapy. SCN5A could promote proliferation and invasiveness potential through regulating cell cycle and epithelial-mesenchymal transition in colorectal cancer cells. Furthermore, SCN5A regulated Ras signaling by stabilizing KRas-calmodulin complex through Ca2+ influx. Apart from that, under 5-fluorouracil treatment, SCN5A promoted calmodulin-dependent apoptosis in colorectal cancers.
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Project description:SCN5A coding for sodium channels in the heart and its reduced activity implicated various biological processes including fibrogenesis. However, the mechanistic interplay between loss of SCN5A activity and cardiac fibrosis pertinence remains elusive. In-vitro knockdown of the SCN5A gene activates fibroblasts and increases TGF-β signaling with small-RNA sequencing indicating its impact on miR-452-5P expression in human cardiac fibroblasts (HCF). Mechanistically, miR-452-5p acts as a direct regulator of TGF-β signaling by inhibiting SMAD4 expression, maintaining cellular homeostasis in normal physiological conditions. SCN5A knockdown limits miR-452-5p regulatory function on SMAD4, which further promotes cardiac fibrosis (CF). These results clarify the significant involvement of miR-452-5p in CF development and propose a promising target for potential therapeutic intervention.
2024-06-20 | GSE261598 | GEO
Project description:To date, KCNH2 mutations identified in patients with long QT syndrome type 2 (LQT2) have been extensively studied using heterologous expression systems. While these systems allow for the evaluation of the pathogenicity of specific hERG mutations through the overexpression of mutant channels, they fail to recapitulate the full spectrum of electrophysiological alterations and ion channel remodeling that occur in cardiomyocytes under physiological conditions in LQT. Existing zebrafish and rodent models are also limited in their ability to faithfully model human QT interval abnormalities due to substantial differences in lifespan, size, anatomy, and physiology. For instance, rodents exhibit a much higher heart rate and significantly shorter action potential duration (APD) than humans. Moreover, IKr is the major repolarizing current in human ventricles, whereas its inhibition in rodents has minimal impact on ventricular repolarization, rendering genetic mouse models inadequate for the study of LQT2. Thus, there is a critical need to develop animal models that can more accurately mimic human inherited arrhythmias. To address this gap, we generated a miniature pig model of LQT2, capitalizing on the physiological similarities to humans, as well as advantages in breeding and genome editing compared to non-human primates. To investigate the mechanisms by which KCNH2 mutations lead to LQT, we performed single-nucleus RNA sequencing to compare the transcriptomes of ventricular tissues from KCNH2-mutant pigs and wild-type controls.
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