A Titin Missense Variant Causes Atrial Fibrillation
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE312917 | GEO | 2025/12/08
REPOSITORIES: GEO
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Project description:A Titin Missense Variant Causes Atrial Fibrillation
| PRJNA1377605 | ENA
Project description:Protein truncating mutations in the titin gene are associated with increased risk of atrial fibrillation (AF). However, little is known regarding the underlying pathophysiology. We identified a heterozygous titin truncating variant in a patient with unexplained early-onset AF using whole exome sequencing. We used atrial and ventricular patient induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs), CRISPR/Cas9 genetic correction, and engineered heart tissue (EHT) constructs to evaluate the impact of the titin truncating variant on electrophysiology, sarcomere structure, contractility, and gene expression.
2025-11-25 | GSE234141 | GEO
Project description:Atrial fibrillation (AF), the most common cardiac rhythm disorder, is a major cause of cardiovascular morbidity and mortality. AF is characterized by the rapid and irregular activation of the atrium with diverse abnormalities, including electrical, structural, metabolic, neurohormonal, or molecular alterations.3 Although the pathophysiology of AF is complex, it has traditionally been treated with antiarrhythmic drugs that control the rhythm by altering cardiac electrical properties, principally by modulating ion channel function. However, treatments of AF with antiarrhythmic drugs have mostly failed to control the heart rhythm, because the electrical characteristics of atrial cardiomyocytes are eventually altered or remodeled during the course of AF. The aims of this study were to characterize the global changes in miRNA expression in human atrial appendages and to identify the target ion channel(s) responsible for electrical remodeling in AF. In this study, we performed a comprehensive analysis of miRNA microarrays, using a strict selection for human samples.
2017-04-25 | GSE68475 | GEO
Project description:Background: Horses are one of the few animals that spontaneously develop atrial fibrillation (AF), making them a powerful model for studying AF mechanisms and treatment effects. Despite the initial effectiveness of treatment in both horses and humans, AF-induced atrial remodelling compromises long-term success. Observational studies have suggested that metformin reduces the risk of AF, but its effects on progressive AF-induced atrial remodelling have not yet been evaluated in a high-fidelity large animal model. Methods: Here, we employed a longitudinal horse model of tachypacing-induced self-sustained AF to characterize the electrical, molecular, and metabolic atrial changes over four months of disease, with and without metformin treatment. Electrophysiological and multi-omic approaches were combined with histology, echocardiography, biochemical and mitochondrial analyses to evaluate disease progression and treatment response. Results: The horse model replicated critical aspects of AF-induced atrial remodelling observed in humans, including electrical and structural changes. Despite upregulation of metabolic genes and proteins in AF, no significant ultrastructural mitochondrial changes were detected. Metformin-treated horses were less susceptible to AF and sustained a less complex AF substrate in the right atrium after four months of disease. These effects were associated with increased activity of the metabolic regulator, AMP-activated kinase (AMPK) , changes in metabolic pathways and modulation of ion-channel gene expression. Metformin did not appear to alter left atrial substrate remodelling. Conclusion: Metformin treatment conferred electrical protection in both the early and later stages of AF in a translationally relevant preclinical model. These findings support metformin as a lead molecul ar for AF-prevention, warranting further mechanistic and clinical studies.
2025-12-03 | PXD059963 | Pride
Project description:Electrical and structural remodeling processes are contributors to the self-perpetuating nature of atrial fibrillation (AF). However, their correlation has not been clarified. In this study, human atrial tissues from the patients with rheumatic mitral valve disease in either sinus rhythm or persistent AF were analyzed using a combined transcriptomic and proteomic approach. An up-regulation in chloride intracellular channel (CLIC) 1, 4, 5 and a rise in type IV collagen were revealed. Combined with the results from immunohistochemistry and electron microscope analysis, the distribution of type IV collagen and effects of fibrosis on myocyte membrane indicated the possible interaction between CLIC and type IV collagen, confirmed by protein structure prediction and co-immunoprecipitation. These results indicate that CLICs play an important role in the development of atrial fibrillation and that CLICs and structural type IV collagen may interact on each other to promote the development of AF in rheumatic mitral valve disease.
2018-11-22 | PXD006911 | Pride
Project description:Background: Atrial fibrillation (AF) is commonly associated with diastolic dysfunction. Both conditions involve overactivation of inflammatory signaling and cardiac fibroblasts (FBs). While the activation of the NLRP3-inflammasome in cardiomyocytes is known to cause atrial electrical remodeling and arrhythmogenicity, the role of FB NLRP3-inflammasome in heart disease is unknown. Objectives: We aimed to elucidate the contribution of FB-specific NLRP3-inflammasome activation to cardiac function and arrhythmogenesis. Methods: Human atrial FBs were isolated from atrial biopsies of AF and sinus rhythm patients. We established an FB-specific knockin (FB-KI) mouse model with FB-restricted expression of constitutively active NLRP3. Cardiac function and AF susceptibility were assessed through echocardiography, tissue Doppler, programmed electrical stimulation, and optical mapping. Results: NLRP3 and IL1B were upregulated in atrial FBs of patients with persistent AF. FB-KI mice exhibited enlarged left atria, enhanced AF-susceptibility, and heart failure with diastolic dysfunction. FBs from FB-KI mice were more transdifferentiated, migratory, and proliferative than those from control. FB-KI mice showed increased fibrous content in both atria and ventricles, atrial gap junction remodeling, and reduced atrial conduction velocity. Single-nuclei RNA-seq analysis revealed prominent transcript remodeling of metabolic pathways across multiple cell types, enhanced extracellular matrix signaling, and altered intercellular communications. Knockdown of Nlrp3 in FBs via adeno-associated virus type-dj/8 mediated transfer of shRNA reduced AF-susceptibility and prevented cardiomyopathy in FB-KI mice. Conclusions: FB-restricted activation of the NLRP3-inflammasome promotes cardiac fibrosis and AF-susceptibility. This study identifies the FB NLRP3-inflammasome activation as a key mechanism governing the concomitant AF and heart failure with diastolic dysfunction.
2025-05-09 | GSE218250 | GEO
Project description:Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia treatable with antiarrhythmic drugs, but patient responses are highly variable. Human induced pluripotent stem cell-derived atrial cardiomyocytes (iPSC-aCMs) are useful for discovering precision therapeutics, but current platforms yield an immature cellular phenotype and are not easily scalable for high-throughput screening. Here, we report that primary adult atrial, but not ventricular, fibroblasts induced greater functional iPSC-aCM maturation, partly through connexin-40 and ephrin-B1 signaling. We developed a protein patterning process within industry-standard multiwell plates to engineer patterned co-culture (PC) of iPSC-aCMs and atrial fibroblasts that significantly enhanced iPSC-aCM structural, electrical, contractile, and metabolic maturation for 6+ weeks versus conventional mono-/co-cultures. PC displayed greater sensitivity for detecting drug efficacy than monocultures, and enabled the modeling and pharmacological or gene editing treatment of an AF-like electrophysiological phenotype due to a sodium channel mutation. In conclusion, PC is useful to elucidate heterotypic cell signaling in the atria, drug screening, and to model AF.
2024-01-19 | GSE239317 | GEO
Project description:Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia treatable with antiarrhythmic drugs, but patient responses are highly variable. Human induced pluripotent stem cell-derived atrial cardiomyocytes (iPSC-aCMs) are useful for discovering precision therapeutics, but current platforms yield an immature cellular phenotype and are not easily scalable for high-throughput screening. Here, we report that primary adult atrial, but not ventricular, fibroblasts induced greater functional iPSC-aCM maturation, partly through connexin-40 and ephrin-B1 signaling. We developed a protein patterning process within industry-standard multiwell plates to engineer patterned co-culture (PC) of iPSC-aCMs and atrial fibroblasts that significantly enhanced iPSC-aCM structural, electrical, contractile, and metabolic maturation for 6+ weeks versus conventional mono-/co-cultures. PC displayed greater sensitivity for detecting drug efficacy than monocultures, and enabled the modeling and pharmacological or gene editing treatment of an AF-like electrophysiological phenotype due to a sodium channel mutation. In conclusion, PC is useful to elucidate heterotypic cell signaling in the atria, drug screening, and to model AF.
2024-01-19 | GSE239321 | GEO
Project description:Atrial fibrillation (AF) is a progressive arrhythmia for which current therapy is inadequate. During AF, rapid stimulation causes atrial remodeling that promotes further AF. The cellular signals that trigger this process remain poorly understood, however, and elucidation of these factors would likely identify new therapeutic targets. We have previously shown that immortalized mouse atrial (HL-1) myocytes subjected to 24 hr of rapid stimulation in culture undergo remodeling similar to that seen in animal models of atrial tachycardia (AT) and human AF. This preparation is devoid of confounding in vivo variables that can modulate gene expression (e.g., hemodynamics). Therefore, we investigated the transcriptional profile associated with early atrial cell remodeling. RNA was harvested from HL-1 cells cultured for 24 hr in the absence and presence of rapid stimulation and subjected to microarray analysis. Data were normalized using Robust Multichip Analysis (RMA), and genes exhibiting significant differential expression were identified using the Significance Analysis of Microarrays (SAM) method. Using this approach, 919 genes were identified that were significantly altered with rapid stimulation (763 up-regulated and 156 down-regulated). For many individual transcripts, changes typical of AF/AT were observed, with marked up-regulation of genes encoding BNP and ANP precursors, heat shock proteins, and MAP kinases, while novel signaling pathways and molecules were also identified. Both stress and survival response were evident, as well as up-regulation of multiple transcription factors. Genes were also functionally classified based on cellular component, biologic process, and molecular function using the Gene Ontology database to permit direct comparison of our data with other gene sets regulated in human AF and experimental AT. For broad categories of genes grouped by functional classification, there was striking conservation between rapidly stimulated HL-1 cells and AF/AT. Results were confirmed using real-time quantitative RT-PCR on 13 genes selected by physiological relevance in AF/AT and regulation in the microarray analysis (up, down, and nonregulated). Rapidly-stimulated atrial myocytes provide a complementary experimental paradigm to explore the initial cellular signals in AT remodeling to identify novel targets in the treatment of AF. Experiment Overall Design: HL-1 cell expression profile in vitro with and without rapid electric stimulation
2008-10-26 | E-GEOD-10598 | biostudies-arrayexpress
Project description:Background Atrial fibrosis plays a critical role in the development of atrial fibrillation (AF). Exosome is a promising cell-free therapeutic approach for the treatment of AF. The purpose of this study was to explore the mechanisms underlying exosomes derived from atrial myocytes regulated atrial remodeling and ask whether their manipulation allows for therapeutic modulation of fibrosis potential abnormalities during AF. Methods We isolated exosomes from atrial myocytes and patients serum, microRNA (miRNA) sequencing analyzed the exosomal miRNAs in atrial myocytes-exosomes and patients serum-exosomes. mRNA sequencing and bioinformatics analysis corroborate the key gene as direct targets of miR-210-3p. Results The miRNAs sequencing analysis identified that miR-210-3p expression significantly increased in exosomes of tachypacing atrial myocytes and serum of AF patients. In vitro, the analysis showed that miR-210-3p inhibitor reversed tachypacing-induced proliferation and collagen synthesis in atrial fibroblasts. Accordingly, KO miR-210-3p could reduce the incidence of AF and ameliorate atrial fibrosis induced by Ang Ⅱ. The mRNA sequencing analysis and Dual-Luciferase reporter assay proved that glycerol-3-phosphate dehydrogenase 1-like (GPD1L) is the potential target gene of miR-210-3p. The functional analysis suggests that GPD1L regulated atrial fibrosis via PI3K/AKT signaling pathway. Besides, silencing GPD1L in atrial fibroblasts induced cells proliferation and these effects could be reversed by PI3K inhibitor (LY294002). Conclusion We demonstrate that atrial myocytes-derived exosomal miR-210-3p promoted the proliferation and collagen synthesis via inhibiting GPD1L in atrial fibroblasts. Preventing pathological crosstalk between atrial myocytes and fibroblasts may be as a novel target to improve atrial fibrosis in AF.
2022-08-17 | GSE210894 | GEO