Project description:Atrial fibrillation (AF) is the most common abnormality of heart rhythm and is a leading cause of heart failure and stroke. This large-scale meta-analysis of genome-wide association studies (GWAS) increased the power to detect single-nucleotide variant (SNV) associations, and we report more than 350 AF-associated genetic loci. At 139 loci we identified candidate genes related to muscle contractility, cardiac muscle development and cell-cell communication. We next assayed chromatin accessibility by ATAC-seq and histone H3 Lysine 4 trimethylation in stem cell derived atrial cardiomyocytes. We observed a marked increase in chromatin accessibility of our sentinel variants and prioritized genes in atrial cardiomyocytes. Finally, we found that a polygenic risk score (PRS) based on our updated effect estimates improved AF risk prediction compared to the CHARGE-AF clinical risk score and a previously reported PRS for AF. The doubling of known AF risk loci will facilitate a greater understanding of the pathways underlying this heart rhythm disorder.
Project description:Atrial fibrillation (AF) is the most common heart arrhythmia disease. The greatest risk of atrial fibrillation is stroke, and stroke caused by valvular heart disease with atrial fibrillation (AF-VHD) is more serious. the development mechanism from VHD to AF-VHD is not yet clear. The research on expression profiles of lncRNA and mRNA is helpful to explore molecular mechanism in patients with valvular heart disease who develop atrial fibrillation.
Project description:<p>The Massachusetts General Hospital (MGH) Atrial Fibrillation Study was initiated in 2001. The study has enrolled serial probands, unaffected and affected family members with atrial fibrillation. At enrollment participants undergo a structured interview to systematically capture their past medical history, AF treatments, and family history. An electrocardiogram is performed; the results of an echocardiogram are obtained; and blood samples are obtained.</p> <p><b>The Massachusetts General Hospital (MGH) Atrial Fibrillation Study is utilized in the following dbGaP substudies.</b> To view genotypes, analysis, other molecular data, and derived variables collected in these substudies, please click on the following substudies below or in the "Substudies" box located on the right hand side of this top-level study page phs001001 Massachusetts General Hospital (MGH) Atrial Fibrillation Study. <ul> <li><a href="./study.cgi?study_id=phs001116">phs001116</a> MGH AF CHARGE-S</li> <li><a href="./study.cgi?study_id=phs001117">phs001117</a> MGH AF Exome Sequencing</li> <li><a href="./study.cgi?study_id=phs001118">phs001118</a> MGH AF Medical Resequencing</li> </ul> </p>
Project description:Atrial fibrillation (AF) is the most common persistent arrhythmia that affect 1–2% of the general population. People with AF display an array of complications cardiogenic stroke and systemic embolism caused by hemodynamic instability and blood hypercoagulability in clinical practice. However, it’s still unclear whether and how ubiquitylated proteins react to AF in the left atrial appendage of patients with AF and valvular heart disease. This theory focuses on the changes of ubiquitylated proteins in atrial fibrillation associated with heart valve disease. We firstly widely analysis the proteins ubiquitination in patients with atrial fibrillation.
Project description:Atrial fibrillation (AF) is currently the most prevalent arrhythmia worldwide.Recent clinical data implicate the additional contribution of non-coding RNAs in the pathogenesis of AFï¼which include microRNAs(miRNAs), endogenous small interfering RNAs, PIWIinteracting RNAs, and lncRNA. Notably, a growing number of lncRNAs have been implicated in disease etiology, although an association with AF has not been reported. In the present study, we conducted an integrated analysis of dysregulated lncRNA and mRNA expression profiles in myocardial sleevesof pulmonary veins between the patients who develop AF and the patients who were in normal sinus rhythm, which was performed using a second generation lncRNA microarrayï¼focusing specifically on the identification and characterization of lncRNAs and mRNA potentially involving in maintaining atrial fibrillation. We conducted an integrated analysis of myocardial sleeves of pulmonary veinsï¼PVsï¼from 12 patients (6 non-AF and 6AF) in our center, of which hypertension, diabetes, smoking and alcohol abuse were excluded, using a second generation lncRNA microarray
Project description:Background: Atrial fibrillation (AF) causes atrial remodeling, and the left atrium (LA) is the favored substrate for maintaining AF. However, it remains unclear if AF remodels both atria differently and contributes to LA arrhythmogenesis and thrombogenesis. Results: AF was associated with differential LA-to-RA gene expression related to specific ion channels and pathways as well as upregulation of thrombogenesis-related genes in the LA appendage. Targeting the molecular mechanisms underlying the LA-to-RA difference and AF-related remodeling in the LA appendage may help provide new therapeutic options in treating AF and preventing thromboembolism in AF. Paired left atrial and right atrial specimens were obtained from 13 patients with persistent AF receiving valvular surgery. The Paired specimens were sent for microarray comparison. Selected results were validated by quantitative real time-PCR (q-PCR) and Western blotting. Ultrastructural changes in the atria were evaluated by immunohistochemistry.
Project description:Objectives: We studied the signal transduction of atrial structural remodelling that contributes to the pathogenesis of atrial fibrillation (AF). Backround: Fibrosis is a hallmark of arrhythmogenic structural remodelling but the underlying molecular mechanisms are incompletely understood. Methods: We performed transcriptional profiling of left atrial myocardium (LA) from patients with AF and sinus rhythm (SR) and applied cultured primary cardiac cells and transgenic mice with overexpression of constitutively active V12Rac1 (RacET) who develop AF at old age to characterize mediators of the signal transduction of atrial remodeling. Results: LA from patients with AF showed a marked upregulation of connective tissue growth factor (CTGF) expression compared SR patients. This was associated with increased fibrosis, NADPH-oxidase-, Rac1- and RhoA activity, upregulation of N-cadherin and connexin 43 (Cx43) expression and increased angiotensin II tissue concentration. In neonatal rat cardiac myocytes and -fibroblasts, a specific small molecule inhibitor of Rac1 or simvastatin completely prevented the angiotensin II induced upregulation of CTGF, Cx43 and N-cadherin expression. Transfection with small-inhibiting CTGF RNA blocked Cx43 and N-cadherin expression. RacET mice showed upregulation of CTGF, Cx43 and N-cadherin protein expression. Inhibition of Rac1 by oral statin treatment prevented these effects, identifying Rac1 as a key regulator of CTGF in vivo. Conclusion: The data identify CTGF as an important mediator of atrial structural remodelling during AF. Angiotensin II activates CTGF via activation of Rac1 and NADPH oxidase, leading to upregulation of Cx43, N-cadherin and interstitial fibrosis and therefore contributing to the signal transduction of atrial structural remodelling. Array design study consists of 5 Atrial Fibrillation patients and matched 5 samples of patients in sinus rhythm (controls).
Project description:Genome-wide association studies (GWAS) have linked hundreds of loci to cardiac diseases. However, in most loci the causal variants and their target genes remain unknown. We developed a combined experimental and analytical approach that integrates single cell epigenomics with GWAS to prioritize risk variants and genes. We profiled accessible chromatin in single cells obtained from human hearts and leveraged the data to study genetics of Atrial Fibrillation (AF), the most common cardiac arrhythmia. Enrichment analysis of AF risk variants using cell-type-resolved open chromatin regions (OCRs) implicated cardiomyocytes as the main mediator of AF risk. We then performed statistical fine-mapping, leveraging the information in OCRs, and identified putative causal variants in 122 AF-associated loci. Taking advantage of the fine-mapping results, our novel statistical procedure for gene discovery prioritized 45 high-confidence risk genes, highlighting transcription factors and signal transduction pathways important for heart development. We further leveraged our single-cell data to study genetics of gene expression. An unexpected finding from earlier studies is that expression QTLs (eQTLs) are often shared across tissues even though most regulatory elements are cell-type specific. We found that this sharing is largely driven by the limited power of eQTL studies using bulk tissues to detect cell-type-specific regulatory variants. This finding points to an important limitation of using eQTLs to interpret GWAS of complex traits. In summary, our analysis provides a comprehensive map of AF risk variants and genes, and a general framework to integrate single-cell genomics with genetic studies of complex traits.