Pharmacological Modulation of Calcium Homeostasis in Familial Dilated Cardiomyopathy: An In Vitro Analysis From an RBM20 Patient-Derived iPSC Model.
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ABSTRACT:
SUBMITTER: Wyles SP
PROVIDER: S-EPMC4902766 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND:Whole exome sequencing is a powerful technique for Mendelian disease gene discovery. However, variant prioritization remains a challenge. We applied whole exome sequencing to identify the causal variant in a large family with familial dilated cardiomyopathy of unknown pathogenesis. METHODS AND RESULTS:A large family with autosomal dominant, familial dilated cardiomyopathy was identified. Exome capture and sequencing were performed in 3 remotely related, affected subjects predicted to share <0.1% of their genomes by descent. Shared variants were filtered for rarity, evolutionary conservation, and predicted functional significance, and remaining variants were filtered against 71 locally generated exomes. Variants were also prioritized using the Variant Annotation Analysis and Search Tool. Final candidates were validated by Sanger sequencing and tested for segregation. There were 664 shared heterozygous nonsense, missense, or splice site variants, of which 26 were rare (minor allele frequency ?0.001 or not reported) in 2 public databases. Filtering against internal exomes reduced the number of candidates to 2, and of these, a single variant (c.1907 G>A) in RBM20, segregated with disease status and was absent in unaffected internal reference exomes. Bioinformatic prioritization with Variant Annotation Analysis and Search Tool supported this result. CONCLUSIONS:Whole exome sequencing of remotely related dilated cardiomyopathy subjects from a large, multiplex family, followed by systematic filtering, identified a causal RBM20 mutation without the need for linkage analysis.
| S-EPMC3895490 | biostudies-literature
Project description:Dilated cardiomyopathy (DCM) is a leading cause of heart failure. In families with autosomal-dominant DCM, heterozygous missense mutations were identified in RNA-binding motif protein 20 (RBM20), a spliceosome protein induced during early cardiogenesis. Dermal fibroblasts from two unrelated patients harboring an RBM20 R636S missense mutation were reprogrammed to human induced pluripotent stem cells (hiPSCs) and differentiated to beating cardiomyocytes (CMs). Stage-specific transcriptome profiling identified differentially expressed genes ranging from angiogenesis regulator to embryonic heart transcription factor as initial molecular aberrations. Furthermore, gene expression analysis for RBM20-dependent splice variants affected sarcomeric (TTN and LDB3) and calcium (Ca(2+)) handling (CAMK2D and CACNA1C) genes. Indeed, RBM20 hiPSC-CMs exhibited increased sarcomeric length (RBM20: 1.747 ± 0.238 µm versus control: 1.404 ± 0.194 µm; P < 0.0001) and decreased sarcomeric width (RBM20: 0.791 ± 0.609 µm versus control: 0.943 ± 0.166 µm; P < 0.0001). Additionally, CMs showed defective Ca(2+) handling machinery with prolonged Ca(2+) levels in the cytoplasm as measured by greater area under the curve (RBM20: 814.718 ± 94.343 AU versus control: 206.941 ± 22.417 AU; P < 0.05) and higher Ca(2+) spike amplitude (RBM20: 35.281 ± 4.060 AU versus control:18.484 ± 1.518 AU; P < 0.05). ?-adrenergic stress induced with 10 µm norepinephrine demonstrated increased susceptibility to sarcomeric disorganization (RBM20: 86 ± 10.5% versus control: 40 ± 7%; P < 0.001). This study features the first hiPSC model of RBM20 familial DCM. By monitoring human cardiac disease according to stage-specific cardiogenesis, this study demonstrates RBM20 familial DCM is a developmental disorder initiated by molecular defects that pattern maladaptive cellular mechanisms of pathological cardiac remodeling. Indeed, hiPSC-CMs recapitulate RBM20 familial DCM phenotype in a dish and establish a tool to dissect disease-relevant defects in RBM20 splicing as a global regulator of heart function.
| S-EPMC4706113 | biostudies-literature
Project description:Dilated cardiomyopathy (DCM) is a heart muscle disease characterized by ventricular dilatation and impaired systolic function. Patients with DCM suffer from heart failure, arrhythmia, and are at risk of premature death. DCM has a prevalence of one case out of 2500 individuals with an incidence of 7/100,000/year (but may be under diagnosed). In many cases the disease is inherited and is termed familial DCM (FDC). FDC may account for 20-48% of DCM. FDC is principally caused by genetic mutations in FDC genes that encode for cytoskeletal and sarcomeric proteins in the cardiac myocyte. Family history analysis is an important tool for identifying families affected by FDC. Standard criteria for evaluating FDC families have been published and the use of such criteria is increasing. Clinical genetic testing has been developed for some FDC genes and will be increasingly utilized for evaluating FDC families. Through the use of family screening by pedigree analysis and/or genetic testing, it is possible to identify patients at earlier, or even presymptomatic stages of their disease. This presents an opportunity to invoke lifestyle changes and to provide pharmacological therapy earlier in the course of disease. Genetic counseling is used to identify additional asymptomatic family members who are at risk of developing symptoms, allowing for regular screening of these individuals. The management of FDC focuses on limiting the progression of heart failure and controlling arrhythmia, and is based on currently accepted treatment guidelines for DCM. It includes general measures (salt and fluid restriction, treatment of hypertension, limitation of alcohol intake, control of body weight, moderate exercise) and pharmacotherapy. Cardiac resynchronization, implantable cardioverter defibrillators and left ventricular assist devices have progressively expanding usage. Patients with severe heart failure, severe reduction of the functional capacity and depressed left ventricular ejection fraction have a low survival rate and may require heart transplant.
| S-EPMC1559590 | biostudies-literature
Project description:The genetic basis of most of dilated cardiomyopathy (DCM) cases remains unknown. A recent study indicated that mutations in a highly localized five amino acid hotspot in exon 9 of RBM20, a gene encoding a ribonucleic acid-binding protein, caused aggressive DCM. We undertook this study to confi rm and extend the nature of RBM20 mutations in another DCM cohort. Clinical cardiovascular data, family histories, and blood samples were collected from patients with idiopathic DCM. DNA from 312 DCM probands was sequenced for nucleotide alterations in exons 6 through 9 of RBM20, and additional family members as possible. We found six unique RBM20 rare variants in six unrelated probands (1.9%). Four mutations, two of which were novel (R634W and R636C) and two previously identified (R634Q and R636H), were identified in a five amino acid hotspot in exon 6. Two other novel variants (V535I in exon 6 and R716Q in exon 9) were outside of this hotspot. Age of onset and severity of heart failure were variable, as were arrhythmias and conduction system defects, but many subjects suffered severe heart failure resulting in early death or cardiac transplantation. This article concludes that DCM in patients with RBM20 mutations is associated with advanced disease.
| S-EPMC2898174 | biostudies-literature
Project description:BACKGROUND:Dilated cardiomyopathy (DCM) is a leading cause of heart failure and death. The etiology of DCM is genetically heterogeneous. OBJECTIVES:We sought to define the prevalence of mutations in the RNA splicing protein RBM20 in a large cohort with DCM and to determine whether genetic variation in RBM20 is associated with clinical outcomes. METHODS:Subjects included in the Genetic Risk Assessment of Defibrillator Events (GRADE) study were aged at least 18 years, had an ejection fraction of ?30%, and an implantable cardioverter-defibrillator (ICD). The coding region and splice junctions of RBM20 were screened in subjects with DCM; 2 common polymorphisms in RBM20, rs942077 and rs35141404, were genotyped in all GRADE subjects. RESULTS:A total of 1465 subjects were enrolled in the GRADE study, and 283 with DCM were screened for RBM20 mutations. The mean age of subjects with DCM was 58 ± 13 years, 64% were males, and the mean follow-up time was 24.2 ± 17.1 months after ICD placement. RBM20 mutations were identified in 8 subjects with DCM (2.8%). Mutation carriers had a similar survival, transplantation rate, and frequency of ICD therapy compared with nonmutation carriers. Three of 8 subjects with RBM20 mutations (37.5%) had atrial fibrillation (AF), whereas 19 subjects without mutations (7.4%) had AF (P = .02). Among all GRADE subjects, rs35141404 was associated with AF (minor allele odds ratio = 0.62; 95% confidence interval = 0.44-0.86; P = .006). In the subset of GRADE subjects with DCM, rs35141404 was associated with AF (minor allele odds ratio = 0.58; P = .047). CONCLUSIONS:Mutations in RBM20 were observed in approximately 3% of subjects with DCM. There were no differences in survival, transplantation rate, and frequency of ICD therapy in mutation carriers.
| S-EPMC3516872 | biostudies-literature
Project description:Dilated cardiomyopathy (DCM) is a primary cause of heart failure, life-threatening arrhythmias, and cardiac death. Pathogenic mutations have been identified at the loci of more than 50 genes in approximately 50% of DCM cases, while the etiologies of the remainder have yet to be determined. In this study, we applied whole exome sequencing in combination with segregation analysis to one pedigree with familial DCM, and identified a read-through mutation (c.2459?A?>?C; p.*820Sext*19) in the myosin light chain kinase 3 gene (MYLK3). We then conducted MYLK3 gene screening of 15 DCM patients (7 familial and 8 sporadic) who were negative for mutation screening of the previously-reported cardiomyopathy-causing genes, and identified another case with a MYLK3 frameshift mutation (c.1879_1885del; p.L627fs*41). In vitro experiments and immunohistochemistry suggested that the MYLK3 mutations identified in this study result in markedly reduced levels of protein expression and myosin light chain 2 phosphorylation. This is the first report that MYLK3 mutations can cause DCM in humans. The clinical phenotypes of DCM patients were consistent with MYLK3 loss-of-function mouse and zebrafish models in which cardiac enlargement and heart failure are observed. Our findings highlight an essential role for cardiac myosin light chain kinase in the human heart.
| S-EPMC5727479 | biostudies-literature
Project description:INTRODUCTION:Dilated cardiomyopathy (DCM) is the most common cardiomyopathy and occurs often in families. As an inherited disease, understanding the significance of diagnostic procedures and genetic screening within families is of utmost importance. AREAS COVERED:Genetic studies have shown that in 30-40% of familial DCM (FDC) cases a causative genetic mutation can be identified. Successful genetic analysis is highly dependent on close examination of patient and family history, and clinical guidelines exist recommending genetic testing to aid in the evaluation of family members at risk of developing FDC. Clinical genetic testing offers a resource for families to identify the etiology of their disease, and in some cases may provide clinical prognostic insight. EXPERT OPINION:As an inherited disease, future FCD studies will focus on elucidating the remaining 60-70% of genetic causes in inherited cases and the pathogenic mechanisms leading to the phenotype. Specifically, a focus on regulatory regions, copy number variation, genetic and environmental modifiers and functional confirmatory investigations will be essential.
| S-EPMC4988677 | biostudies-literature
Project description:Mutations in RNA binding motif protein 20 (RBM20) are a common cause of dilated cardiomyopathy (DCM). Many RBM20 mutations cluster within an arginine/serine rich (RS-rich) domain, resulting in mis-localization of RBM20 to ribonucleoprotein granules within the cytoplasm, abnormal splicing of cardiac genes, and cardiomyocyte dysfunction. We used adenine base editing (ABE) and prime editing to correct pathogenic p.R634Q and p.R636S mutations in the RS-rich domain in human isogenic induced pluripotent stem cell-derived cardiomyocytes. We also created humanized Rbm20R636Q mutant mice, which succumbed to severe cardiac dysfunction, heart failure and premature death. Systemic delivery of ABE components by adeno-associated virus in these mice restored cardiac function and extended life span. These findings demonstrate the potential of precise correction of genetic mutations as a promising therapeutic approach for DCM.
2022-08-11 | GSE210783 | GEO
Project description:Mutations in RNA binding motif protein 20 (RBM20) are a common cause of dilated cardiomyopathy (DCM). Many RBM20 mutations cluster within an arginine/serine rich (RS-rich) domain, resulting in mis-localization of RBM20 to ribonucleoprotein granules within the cytoplasm, abnormal splicing of cardiac genes, and cardiomyocyte dysfunction. We used adenine base editing (ABE) and prime editing to correct pathogenic p.R634Q and p.R636S mutations in the RS-rich domain in human isogenic induced pluripotent stem cell-derived cardiomyocytes. We also created humanized Rbm20R636Q mutant mice, which succumbed to severe cardiac dysfunction, heart failure and premature death. Systemic delivery of ABE components by adeno-associated virus in these mice restored cardiac function and extended life span. These findings demonstrate the potential of precise correction of genetic mutations as a promising therapeutic approach for DCM.
2022-08-14 | GSE211005 | GEO
Project description:Human patients carrying genetic mutations in RBM20 develop a clinically aggressive dilated cardiomyopathy (DCM) characterized by early onset heart failure, high mortality, and sudden death, which is recapitulated in animal models. RBM20 has two primary domains, an RNA recognition motif (RRM) that binds RNA and an arginine/serine (RS)-rich domain that mediates spliceosome assembly and nuclear localization. Reported data showed that mutations in the RS domain lead to severe DCM. Loss of the RRM domain in RBM20 has been shown to disrupt the splicing of RBM20 target transcripts but does not lead to DCM. The objectives of the present study were to determine the functional role of the RS domain in DCM and examine the mechanisms. Mice expressing RBM20 lacking the RS domain (Rbm20ΔRS) were generated using CRISPR/Cas9 technology. Male and female Rbm20ΔRS mice developed a DCM-like phenotype characterized by ventricular dilation and impaired systolic function, that is more severe in females. Splicing of RBM20 target genes, including Ttn, was disrupted in both Rbm20ΔRS and Rbm20ΔRRM mice. However, RBM20 was mis-localized to the sarcoplasm only in the hearts of Rbm20ΔRS mice, indicating that mis-localization of RBM20 rather than disrupted splicing is key in DCM pathogenesis.
2023-01-02 | GSE212799 | GEO