MULTIPLE SCN5A ENHANCERS MODULATE CARDIAC GENE EXPRESSION AND QT INTERVAL VARIATION
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PROVIDER: PRJNA431786 | ENA |
REPOSITORIES: ENA
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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: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: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: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: Not available
| S-EPMC6561183 | biostudies-literature
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:Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used to examine in vitro the effect of mutations in the cardiac sodium channel gene SCN5A, associated with cardiac arrhythmias. Postnatally SCN5A undergoes a fetal-to-adult isoform switch, but hiPSC-CMs in conventional 2-dimensional cultures are fetal-like. This impedes evaluation of mutations in the adult isoform. Here, we derived hiPSC-CMs from a patient carrying compound mutations in the adult SCN5A exon 6B and in exon 4 and generated isogenic corrected lines. In hiPSC-CM 2-dimensional culture, exon 6B mutation did not affect single-cell electrophysiology because of its limited expression. CRISPR/Cas9-mediated excision of the fetal exon 6A with did not promote adult SCN5A expression, rather it impaired the splicing. By maturing hiPSC-CMs in three-dimensional tri-cell type cardiac microtissues, SCN5A underwent isoform switch and revealed the functional effect of exon 6B mutation. Upregulation of the splicing factor MBNL1 in hiPSC-CMs either by culture in microtissues or by overexpression was sufficient to promote exon 6B inclusion. Our results support the ability to study developmentally regulated cardiac genes and postnatal cardiac arrhythmias using hiPSC cardiac cells.
2023-05-03 | GSE180290 | GEO
Project description:Conduction slowing of the electric impulse that drives the heartbeat may evoke lethal cardiac arrhythmias. Mutations in SCN5A, which encodes the pore-forming cardiac sodium channel alpha subunit, are associated with familial arrhythmia syndromes based on conduction slowing. However, disease severity among mutation carriers is highly variable. We hypothesized that genetic modifiers underlie the variability in conduction slowing and disease severity. With the aim of identifying such modifiers, we studied the Scn5a(1798insD/+) mutation in 2 distinct mouse strains, FVB/N and 129P2. In 129P2 mice, the mutation resulted in more severe conduction slowing particularly in the right ventricle (RV) compared to FVB/N. Pan-genomic mRNA expression profiling in the 2 mouse strains uncovered a drastic reduction in mRNA encoding the sodium channel auxiliary subunit beta4 (Scn4b) in 129P2 mice compared to FVB/N. This corresponded to low to undetectable beta4 protein levels in 129P2 ventricular tissue, whereas abundant beta4 protein was detected in FVB/N. Sodium current measurements in isolated myocytes from the 2 mouse strains indicated that sodium channel activation in myocytes from 129P2 mice occurred at more positive potentials compared to FVB/N. Using computer simulations, this difference in activation kinetics was predicted to explain the observed differences in conduction disease severity between the 2 strains. In conclusion, genetically determined differences in sodium current characteristics on the myocyte level modulate disease severity in cardiac sodium channelopathies. In particular, the sodium channel subunit beta4 (SCN4B) may constitute a potential genetic modifier of conduction and cardiac sodium channel disease.
2010-01-12 | GSE19741 | GEO
Project description:BACKGROUND: Brugada syndrome (BrS) is an inherited arrhythmia syndrome caused by loss-of-function variants in the cardiac sodium channel gene SCN5A (sodium voltage-gated channel alpha subunit 5) in ≈20% of subjects. We identified a family with 4 individuals diagnosed with BrS harboring the rare G145R missense variant in the cardiac transcription factor TBX5 (T-box transcription factor 5) and no SCN5A variant. METHODS: We generated induced pluripotent stem cells (iPSCs) from 2 members of a family carrying TBX5-G145R and diagnosed with Brugada syndrome. After differentiation to iPSC-derived cardiomyocytes (iPSC-CMs), electrophysiologic characteristics were assessed by voltage- and current-clamp experiments (n=9 to 21 cells per group) and transcriptional differences by RNA sequencing (n=3 samples per group), and compared with iPSC-CMs in which G145R was corrected by CRISPR/Cas9 approaches. The role of platelet-derived growth factor (PDGF)/phosphoinositide 3-kinase (PI3K) pathway was elucidated by small molecule perturbation. The rate-corrected QT (QTc) interval association with serum PDGF was tested in the Framingham Heart Study cohort (n=1893 individuals). RESULTS: TBX5-G145R reduced transcriptional activity and caused multiple electrophysiologic abnormalities, including decreased peak and enhanced “late” cardiac sodium current (INa), which were entirely corrected by editing G145R to wildtype. Transcriptional profiling and functional assays in genome-unedited and -edited iPSC-CMs showed direct SCN5A downregulation caused decreased peak INa, and that reduced PDGF receptor (PDGFRA [platelet-derived growth factor receptor α]) expression and blunted signal transduction to PI3K was implicated in enhanced late INa. Tbx5 regulation of the PDGF axis and increased arrhythmia risk with disruption of PDGF sigaling were both conserved in murine model systems. PDGF receptor blockade markedly prolonged normal iPSC-CM action potentials and plasma levels of PDGF in the Framingham Heart Study were inversely correlated with the QTc interval (P
2022-12-31 | GSE221945 | GEO
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.
2020-05-09 | GSE150134 | GEO