Project description:Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy primarily of the right ventricle characterized through fibrofatty replacement of cardiomyocytes. The genetic etiology in ARVC patients is most commonly caused by dominant inheritance and high genetic heterogeneity. Though histological examinations of ARVC affected human myocardium reveals fibrolipomatous replacement, the molecular mechanisms leading to loss of cardiomyocytes are largely unknown. We therefore analyzed the transcriptomes of 6 ARVC specimen derived from heart transplantation candidates and compared our findings to 6 non-failing donor hearts (NF) which could not be transplanted for technical reasons. In addition, we compared our findings to 7 hearts from patients with idiopathic dilated cardiomyopathy. From each heart left (LV) and right ventricular (RV) myocardial samples were analyzed by Affymetrix HG-U133 Plus 2.0 arrays, adding up to six sample groups. Unsupervised cluster analyses of the six sample groups revealed a clear separation of NF and cardiomyopathy samples. However, in contrast to the other samples, unsupervised cluster analyses revealed no distinct expression pattern in LV and RV samples from ARVC-hearts. We further identified differentially expressed transcripts using t-tests and found transcripts separating diseased and NF ventricular myocardium. Of note, in failing myocardium only about 15-16% of the genes are commonly regulated compared to NF samples. In addition both cardiomyopathies are clearly distinct on the transcriptome level. Comparison of the expression patterns between the failing RV and LV using a paired t-test revealed a lack of major differences between LV and RV gene expression in ARVC hearts. Microarrays were used to elucidate the differences between non-failing control hearts and those, suffering from arrhythmogenic right ventricular cardiomyopathy (ARVC).
Project description:Arrhythmogenic cardiomyopathy is an inherited entity characterized by irregular cell-cell adhesion, cardiomyocyte death, fibro-fatty replacement of ventricular myocytes, leading to malignant ventricular arrythmias, contractile dysfunction and sudden cardiac death. Pathogenic variants in genes that encode desmosome are the predominant cause of arrhythmogenic cardiomyopathy. Moreover, signalling pathways such as Wnt/ß-catenin and transforming growth factor-β have been involved in the disease progression. However, still little is known about the molecular pathophysiological mechanisms that underlie arrhythmogenic cardiomyopathy pathogenesis. We used mRNA and small RNA sequencing to analyse the transcriptome of health and arrhythmogenic cardiomyopathy autopsied human hearts. Our results showed 697 differentially expressed genes, and eight differentially expressed miRNAs. Functional enrichment revealed mitochondrial respiratory-related pathways, impaired response to oxidative stress, apoptotic signalling pathway, inflammatory response-related and extracellular matrix response pathways. Furthermore, analysis of miRNA-mRNA interactome identified eleven negatively correlated miRNA-target pairs for arrhythmogenic cardiomyopathy. Our finding revealed novel arrhythmogenic cardiomyopathy-related miRNAs with important regulatory function in disease pathogenesis highlighting their value as potential key targets for therapeutic approaches.
Project description:Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy primarily of the right ventricle characterized through fibrofatty replacement of cardiomyocytes. The genetic etiology in ARVC patients is most commonly caused by dominant inheritance and high genetic heterogeneity. Though histological examinations of ARVC affected human myocardium reveals fibrolipomatous replacement, the molecular mechanisms leading to loss of cardiomyocytes are largely unknown. We therefore analyzed the transcriptomes of 6 ARVC specimen derived from heart transplantation candidates and compared our findings to 6 non-failing donor hearts (NF) which could not be transplanted for technical reasons. In addition, we compared our findings to 7 hearts from patients with idiopathic dilated cardiomyopathy. From each heart left (LV) and right ventricular (RV) myocardial samples were analyzed by Affymetrix HG-U133 Plus 2.0 arrays, adding up to six sample groups. Unsupervised cluster analyses of the six sample groups revealed a clear separation of NF and cardiomyopathy samples. However, in contrast to the other samples, unsupervised cluster analyses revealed no distinct expression pattern in LV and RV samples from ARVC-hearts. We further identified differentially expressed transcripts using t-tests and found transcripts separating diseased and NF ventricular myocardium. Of note, in failing myocardium only about 15-16% of the genes are commonly regulated compared to NF samples. In addition both cardiomyopathies are clearly distinct on the transcriptome level. Comparison of the expression patterns between the failing RV and LV using a paired t-test revealed a lack of major differences between LV and RV gene expression in ARVC hearts.
Project description:Several inherited arrhythmias primarily affect the right ventricle, including Brugada syndrome and arrhythmogenic cardiomyopathy, however the molecular basis of this chamber predilection is not well understood. Right and left ventricular cardiomyocytes derive from distinct progenitor populations. Here, we show that Hrt2, a gene associated with Brugada syndrome, is a direct target of Wnt signaling in the right ventricle and Notch signaling in the left ventricle. Perturbations of Wnt and Notch signaling during development and in the adult lead to chamber-specific transcriptional effects on Hrt2 expression associated with distinct binding patterns to Hrt2 enhancers. Differential enhancer binding is present at early developmental stages when the signaling pathways are active and persists into adulthood. Consistent with chamber-specific regulation, mice deficient in Wnt transcriptional activity dysregulate only a small fraction of transcripts in common between ventricles. Wnt target gen es important for cellular electrophysiology are differentially regulated, resulting in perturbed cardiac conduction and cellular electrophysiological parameters only within the right ventricle. Ex vivo and in vivo physiologic stimulation of the right ventricle is sufficient to induce ventricular tachycardia in Wnt transcriptionally inactive hearts, while left ventricular stimulation has no effect. Taken together, these data delineate mechanisms underlying ventricular-specific arrhythmia susceptibility due to embryonic programming.
Project description:Several inherited arrhythmias primarily affect the right ventricle, including Brugada syndrome and arrhythmogenic cardiomyopathy, however the molecular basis of this chamber predilection is not well understood. Right and left ventricular cardiomyocytes derive from distinct progenitor populations. Here, we show that Hrt2, a gene associated with Brugada syndrome, is a direct target of Wnt signaling in the right ventricle and Notch signaling in the left ventricle. Perturbations of Wnt and Notch signaling during development and in the adult lead to chamber-specific transcriptional effects on Hrt2 expression associated with distinct binding patterns to Hrt2 enhancers. Differential enhancer binding is present at early developmental stages when the signaling pathways are active and persists into adulthood. Consistent with chamber-specific regulation, mice deficient in Wnt transcriptional activity dysregulate only a small fraction of transcripts in common between ventricles. Wnt target gen es important for cellular electrophysiology are differentially regulated, resulting in perturbed cardiac conduction and cellular electrophysiological parameters only within the right ventricle. Ex vivo and in vivo physiologic stimulation of the right ventricle is sufficient to induce ventricular tachycardia in Wnt transcriptionally inactive hearts, while left ventricular stimulation has no effect. Taken together, these data delineate mechanisms underlying ventricular-specific arrhythmia susceptibility due to embryonic programming.
Project description:Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is an inherited cardiac disease characterized by fibro-fatty replacement of the myocardium that causes heart failure and sudden cardiac death. The most aggressive subtype of ARVC is ARVC type 5 (ARVC5), caused by a p.S358L mutation in TMEM43. The function and localization of TMEM43 and the mechanism by which the p.S358L mutation causes the disease, are unknown.
Project description:Dilated cardiomyopathy (DCM), a myocardial disorder that can result in progressive heart failure and arrhythmias, is defined by ventricular chamber enlargement and dilatation, and systolic dysfunction. To decipher the basis for the cardiac pathology in titin-mutated patients, we investigated the hypothesis that induced Pluripotent Stem Cell (iPSC)- derived cardiomyocytes (iPSC-CM) generated from patients, recapitulate the disease phenotype.Our findings show that the mutated cardiomyocytes from DCM patients recapitulate abnormalities of the inherited cardiomyopathies.
2019-04-12 | PXD010513 | Pride
Project description:A Rare Case of Arrhythmogenic Right Ventricular Cardiomyopathy Induced by LAMA2 mutation