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ABSTRACT:
PROVIDER: PRJNA1218793 | ENA |
REPOSITORIES: ENA
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Project description:Truncating variants in titin can cause dilated cardiomyopathy, however, the role of missense titin variants is less clear. In humans the heterozygous titin A178D variant is associated with dilated cardiomyopathy with left ventricular non-compaction. Using CRISPR-Cas9 mediated homology-directed repair the A178D titin variant was introduced into a mouse model. Homozygous A178D mice showed features of dilated cardiomyopathy. Total RNA was extracted from the left ventricles of WT and homozygous A178D littermate control mice and RNA-sequencing performed. Different patterns of gene expression were identified in wildtype and homozygous A178D left ventricles.
2021-02-26 | GSE154504 | GEO
Project description:Arrhythmogenic cardiomyopathy (ACM) is frequently attributed to desmosomal mutations, such as those in the desmoplakin (DSP) gene. Patients with DSP- cardiomyopathy are predisposed to myocardial degeneration and arrhythmias. Despite advancements, the underlying molecular mechanisms remain incompletely understood, thus limiting therapeutic options. Here, we employed spatial transcriptomics on an explanted heart from a patient with a pathogenic DSP variant. Our transcriptional analysis revealed endothelial PAS domain-containing protein 1 (EPAS1) as a potential regulator of mitochondrial homeostasis in stressed cardiomyocytes. Elevated EPAS1 levels were associated with mitochondrial dysfunction and hypoxic stress in both human-relevant in vitro ACM models and additional explanted hearts with genetic cardiomyopathy. Collectively, cardiomyocytes bearing pathogenic DSP variants exhibit mitochondrial dysfunction, increased apoptosis, and impaired contractility, which are linked to the increased EPAS1 levels. These findings implicate EPAS1 as a key regulator of myocardial degeneration in DSP-cardiomyopathy, which expand to other forms of ACM.
2025-02-15 | GSE289628 | GEO
Project description:Arrhythmogenic cardiomyopathy (ACM) is frequently attributed to desmosomal mutations, such as those in the desmoplakin (DSP) gene. Patients with DSP- cardiomyopathy are predisposed to myocardial degeneration and arrhythmias. Despite advancements, the underlying molecular mechanisms remain incompletely understood, thus limiting therapeutic options. Here, we employed spatial transcriptomics on an explanted heart from a patient with a pathogenic DSP variant. Our transcriptional analysis revealed endothelial PAS domain-containing protein 1 (EPAS1) as a potential regulator of mitochondrial homeostasis in stressed cardiomyocytes. Elevated EPAS1 levels were associated with mitochondrial dysfunction and hypoxic stress in both human-relevant in vitro ACM models and additional explanted hearts with genetic cardiomyopathy. Collectively, cardiomyocytes bearing pathogenic DSP variants exhibit mitochondrial dysfunction, increased apoptosis, and impaired contractility, which are linked to the increased EPAS1 levels. These findings implicate EPAS1 as a key regulator of myocardial degeneration in DSP-cardiomyopathy, which expand to other forms of ACM.
2025-02-15 | GSE289630 | GEO
Project description:Aims: Pathogenic truncating variants in the largest human protein TITIN are a leading cause of dilated cardiomyopathy. Because of the size of the gene encoding TITIN, many missense variations are identified. These are difficult to evaluate in genetic testing, as even individually rare variants are common in aggregate in normal populations. While the majority will be benign, a small subset is pathogenic, but distinction is challenging. Here, we describe the generation of a mouse model to investigate the underlying disease mechanism of a previously reported TITIN A178D missense variant identified in a family with non-compaction and dilated cardiomyopathy. Methods and Results: Heterozygous and homozygous mice carrying the TITIN A178D missense variant were characterised in vivo. Heterozygous mice had no detectable phenotype at any time point observed (up to 1 year). By contrast, homozygous mice developed dilated cardiomyopathy from 3 months. Chronic adrenergic stimulation aggravated the phenotype. Targeted transcript profiling revealed induction of the fetal gene programme and hypertrophic signalling pathways in homozygous mice, and these were confirmed at the protein level. Unsupervised proteomics identified down-regulation of TELETHONIN and FOUR-AND-A-HALF LIM DOMAIN 2, as well as the up-regulation of heat shock proteins and MYELOID LEUKEMIA FACTOR 1. Loss of TELETHONIN from the cardiac Z-disc was accompanied by proteasomal degradation; however, TELETHONIN also accumulated in the cytoplasm. In parallel, a proteo-toxic response was observed in the mice. Conclusions: We have shown that the TITIN A178D missense variant is pathogenic in homozygous mice, resulting in cardiomyopathy. We also provide evidence of the disease mechanism. Because the TITIN A178D variant abolishes binding of TELETHONIN, this leads to its abnormal cytoplasmic accumulation. Subsequent degradation of TELETHONIN by the proteasome results in proteasomal overload, and activation of a proteo-toxic response. The latter appears to be a driving factor for the cardiomyopathy observed in the mouse model.
2021-03-01 | PXD020390 | Pride
Project description:Loss of the PR domain 16 (PRDM16) genetic locus has been suggested as the needed trigger for the development of left ventricular non-compaction cardiomyopathy (LVNC) and dilated cardiomyopathy (DCM) in patients with 1p36 deletion syndrome. Furthermore, lack of Prdm16 in the murine heart has recently been shown to cause a spectrum of cardiomyopathy phenotypes. In spite of these advances, our understanding of the downstream transcriptional pathways regulated by PRDM16 that lead to these cardiac phenotypes is limited. OBJECTIVE: to unveil the downstream transcriptional pathways involved in the development of cardiomyopathy phenotypes associated with PRDM16 mutations/deletion in human and mice. METHODS AND RESULTS: We hypothesized that PRDM16 acts as an upstream regulator of key transcriptional pathways involved in cardiac maturation. Induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with a PRDM16 variant, cardiac tissue from mice expressing the human variant, mice with cardiac-specific deletion of Prdm16 and in vitro gain and loss of Prdm16 function were employed. Here we show that de novo pathogenic variants in PRDM16 are sufficient to cause LVNC in humans. In contrast, haploinsufficiency or complete deletion of Prdm16 in cardiomyocytes in mice led to pathological hypertrophy and dilated cardiomyopathy respectively. We demonstrated that PRDM16 regulates cardiac maturation through the maintenance of estrogen-related receptors (ERRs) expression. By contrast, PRDM16 acts as a supressor of transforming growth factor beta (TGFB) signaling. CONCLUSIONS: PRDM16 is a novel regulator of cardiac maturation acting upstream of ERRs and their regulators, and a suppressor of fibrotic signaling including TGFB.
2023-12-01 | GSE193877 | GEO
Project description:Loss of the PR domain 16 (PRDM16) genetic locus has been suggested as the needed trigger for the development of left ventricular non-compaction cardiomyopathy (LVNC) and dilated cardiomyopathy (DCM) in patients with 1p36 deletion syndrome. Furthermore, lack of Prdm16 in the murine heart has recently been shown to cause a spectrum of cardiomyopathy phenotypes. In spite of these advances, our understanding of the downstream transcriptional pathways regulated by PRDM16 that lead to these cardiac phenotypes is limited. OBJECTIVE: to unveil the downstream transcriptional pathways involved in the development of cardiomyopathy phenotypes associated with PRDM16 mutations/deletion in human and mice. METHODS AND RESULTS: We hypothesized that PRDM16 acts as an upstream regulator of key transcriptional pathways involved in cardiac maturation. Induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with a PRDM16 variant, cardiac tissue from mice expressing the human variant, mice with cardiac-specific deletion of Prdm16 and in vitro gain and loss of Prdm16 function were employed. Here we show that de novo pathogenic variants in PRDM16 are sufficient to cause LVNC in humans. In contrast, haploinsufficiency or complete deletion of Prdm16 in cardiomyocytes in mice led to pathological hypertrophy and dilated cardiomyopathy respectively. We demonstrated that PRDM16 regulates cardiac maturation through the maintenance of estrogen-related receptors (ERRs) expression. By contrast, PRDM16 acts as a supressor of transforming growth factor beta (TGFB) signaling. CONCLUSIONS: PRDM16 is a novel regulator of cardiac maturation acting upstream of ERRs and their regulators, and a suppressor of fibrotic signaling including TGFB.
2023-12-01 | GSE193873 | GEO
Project description:Truncating variant in MYOF gene is associated with limb-girdle type muscular dystrophy and cardiomyopathy
| PRJNA487792 | ENA
Project description:Pathogenic variants in ACTN2, coding for alpha-actinin 2, are known to be rare causes of Hyper-trophic Cardiomyopathy. However, little is known about the underlying disease mechanisms. Adult heterozygous mice carrying the Actn2 M228T variant were phenotyped by echocardiog-raphy. For homozygous mice, viable E15.5 embryonic hearts were analysed by High Resolution Episcopic Microscopy and wholemount staining, complemented by unbiased proteomics, qPCR and Western blotting. Heterozygous Actn2 M228T mice have no overt phenotype. Only mature males show molecular parameters indicative of cardiomyopathy. By contrast, the variant is em-bryonically lethal in the homozygous setting and E15.5 hearts show multiple morphological ab-normalities. Molecular analyses, including unbiased proteomics, identified quantitative abnormal-ities in sarcomeric parameters, cell cycle defects and mitochondrial dysfunction. The mutant al-pha-actinin protein is found to be destabilised, associated with increased activity of the ubiqui-tin-proteosomal system. This missense variant in alpha-actinin renders the protein less stable. In response, the ubiquitin-proteosomal system is activated; a mechanism which has been implicated in cardiomyopathies previously. In parallel, lack of functional alpha-actinin is thought to cause energetic defects through mitochondrial dysfunction. This seems, together with cell cycle defects, the likely cause of death of the embryos. The defects also have wide-ranging morphological con-sequences.
2023-05-10 | PXD039226 | Pride
Project description:Circulating ceRNAs associated with hypertrophic cardiomyopathy
| PRJNA625111 | ENA