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Gregorich ZR, Yanghai Z, Kamp TJ, Granzier H, Guo W. Mechanisms of RBM20 Cardiomyopathy: Insights From Model Systems. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2024; 17:e004355. [PMID: 38288598 PMCID: PMC10923161 DOI: 10.1161/circgen.123.004355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2024]
Abstract
RBM20 (RNA-binding motif protein 20) is a vertebrate- and muscle-specific RNA-binding protein that belongs to the serine-arginine-rich family of splicing factors. The RBM20 gene was first identified as a dilated cardiomyopathy-linked gene over a decade ago. Early studies in Rbm20 knockout rodents implicated disrupted splicing of RBM20 target genes as a causative mechanism. Clinical studies show that pathogenic variants in RBM20 are linked to aggressive dilated cardiomyopathy with early onset heart failure and high mortality. Subsequent studies employing pathogenic variant knock-in animal models revealed that variants in a specific portion of the arginine-serine-rich domain in RBM20 not only disrupt splicing but also hinder nucleocytoplasmic transport and lead to the formation of RBM20 biomolecular condensates in the sarcoplasm. Conversely, mice harboring a disease-associated variant in the RRM (RNA recognition motif) do not show evidence of adverse remodeling or exhibit sudden death despite disrupted splicing of RBM20 target genes. Thus, whether disrupted splicing, biomolecular condensates, or both contribute to dilated cardiomyopathy is under debate. Beyond this, additional questions remain, such as whether there is sexual dimorphism in the presentation of RBM20 cardiomyopathy. What are the clinical features of RBM20 cardiomyopathy and why do some individuals develop more severe disease than others? In this review, we summarize the reported observations and discuss potential mechanisms of RBM20 cardiomyopathy derived from studies employing in vivo animal models and in vitro human-induced pluripotent stem cell-derived cardiomyocytes. Potential therapeutic strategies to treat RBM20 cardiomyopathy are also discussed.
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Affiliation(s)
- Zachery R. Gregorich
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
| | - Zhang Yanghai
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
| | - Timothy J. Kamp
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
- Cardiovascular Research Center, University of Wisconsin-Madison, Madison, WI
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ
| | - Wei Guo
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI
- Cardiovascular Research Center, University of Wisconsin-Madison, Madison, WI
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Wang C, Zhang Y, Methawasin M, Braz CU, Gao-Hu J, Yang B, Strom J, Gohlke J, Hacker T, Khatib H, Granzier H, Guo W. RBM20 S639G mutation is a high genetic risk factor for premature death through RNA-protein condensates. J Mol Cell Cardiol 2022; 165:115-129. [PMID: 35041844 PMCID: PMC8940686 DOI: 10.1016/j.yjmcc.2022.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/03/2022] [Accepted: 01/09/2022] [Indexed: 12/13/2022]
Abstract
Dilated cardiomyopathy (DCM) is a heritable and genetically heterogenous disease often idiopathic and a leading cause of heart failure with high morbidity and mortality. DCM caused by RNA binding motif protein 20 (RBM20) mutations is diverse and needs a more complete mechanistic understanding. RBM20 mutation S637G (S639G in mice) is linked to severe DCM and early death in human patients. In this study, we generated a RBM20 S639G mutation knock-in (KI) mouse model to validate the function of S639G mutation and examine the underlying mechanisms. KI mice exhibited severe DCM and premature death with a ~ 50% mortality in two months old homozygous (HM) mice. KI mice had enlarged atria and increased ANP and BNP biomarkers. The S639G mutation promoted RBM20 trafficking and ribonucleoprotein (RNP) granules in the sarcoplasm. RNA Seq data revealed differentially expressed and spliced genes were associated with arrhythmia, cardiomyopathy, and sudden death. KI mice also showed a reduction of diastolic stiffness and impaired contractility at both the left ventricular (LV) chamber and cardiomyocyte levels. Our results indicate that the RBM20 S639G mutation leads to RNP granules causing severe heart failure and early death and this finding strengthens the novel concept that RBM20 cardiomyopathy is a RNP granule disease.
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Affiliation(s)
- Chunyan Wang
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Yanghai Zhang
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Mei Methawasin
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Camila Urbano Braz
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Jeffrey Gao-Hu
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Betty Yang
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Joshua Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Jochen Gohlke
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Timothy Hacker
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Hasan Khatib
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Wei Guo
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI 53706, USA.
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Abstract
PURPOSE OF REVIEW This review aims to give an update on recent findings related to the cardiac splicing factor RNA-binding motif protein 20 (RBM20) and RBM20 cardiomyopathy, a form of dilated cardiomyopathy caused by mutations in RBM20. RECENT FINDINGS While most research on RBM20 splicing targets has focused on titin (TTN), multiple studies over the last years have shown that other splicing targets of RBM20 including Ca2+/calmodulin-dependent kinase IIδ (CAMK2D) might be critically involved in the development of RBM20 cardiomyopathy. In this regard, loss of RBM20 causes an abnormal intracellular calcium handling, which may relate to the arrhythmogenic presentation of RBM20 cardiomyopathy. In addition, RBM20 presents clinically in a highly gender-specific manner, with male patients suffering from an earlier disease onset and a more severe disease progression. Further research on RBM20, and treatment of RBM20 cardiomyopathy, will need to consider both the multitude and relative contribution of the different splicing targets and related pathways, as well as gender differences.
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Spracklen TF, Chakafana G, Schwartz PJ, Kotta MC, Shaboodien G, Ntusi NAB, Sliwa K. Genetics of Peripartum Cardiomyopathy: Current Knowledge, Future Directions and Clinical Implications. Genes (Basel) 2021; 12:genes12010103. [PMID: 33467574 PMCID: PMC7830587 DOI: 10.3390/genes12010103] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 02/07/2023] Open
Abstract
Peripartum cardiomyopathy (PPCM) is a condition in which heart failure and systolic dysfunction occur late in pregnancy or within months following delivery. Over the last decade, genetic advances in heritable cardiomyopathy have provided new insights into the role of genetics in PPCM. In this review, we summarise current knowledge of the genetics of PPCM and potential avenues for further research, including the role of molecular chaperone mutations in PPCM. Evidence supporting a genetic basis for PPCM has emanated from observations of familial disease, overlap with familial dilated cardiomyopathy, and sequencing studies of PPCM cohorts. Approximately 20% of PPCM patients screened for cardiomyopathy genes have an identified pathogenic mutation, with TTN truncations most commonly implicated. As a stress-associated condition, PPCM may be modulated by molecular chaperones such as heat shock proteins (Hsps). Recent studies have led to the identification of Hsp mutations in a PPCM model, suggesting that variation in these stress-response genes may contribute to PPCM pathogenesis. Although some Hsp genes have been implicated in dilated cardiomyopathy, their roles in PPCM remain to be determined. Additional areas of future investigation may include the delineation of genotype-phenotype correlations and the screening of newly-identified cardiomyopathy genes for their roles in PPCM. Nevertheless, these findings suggest that the construction of a family history may be advised in the management of PPCM and that genetic testing should be considered. A better understanding of the genetics of PPCM holds the potential to improve treatment, prognosis, and family management.
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Affiliation(s)
- Timothy F. Spracklen
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Graham Chakafana
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Peter J. Schwartz
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, 20135 Milan, Italy;
| | - Maria-Christina Kotta
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, 20135 Milan, Italy;
| | - Gasnat Shaboodien
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Ntobeko A. B. Ntusi
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- Cape Universities Body Imaging Centre, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Karen Sliwa
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- Correspondence:
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Upadhyay SK, Mackereth CD. Structural basis of UCUU RNA motif recognition by splicing factor RBM20. Nucleic Acids Res 2020; 48:4538-4550. [PMID: 32187365 PMCID: PMC7192616 DOI: 10.1093/nar/gkaa168] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/28/2020] [Accepted: 03/07/2020] [Indexed: 12/16/2022] Open
Abstract
The vertebrate splicing factor RBM20 (RNA binding motif protein 20) regulates protein isoforms important for heart development and function, with mutations in the gene linked to cardiomyopathy. Previous studies have identified the four nucleotide RNA motif UCUU as a common element in pre-mRNA targeted by RBM20. Here, we have determined the structure of the RNA Recognition Motif (RRM) domain from mouse RBM20 bound to RNA containing a UCUU sequence. The atomic details show that the RRM domain spans a larger region than initially proposed in order to interact with the complete UCUU motif, with a well-folded C-terminal helix encoded by exon 8 critical for high affinity binding. This helix only forms upon binding RNA with the final uracil, and removing the helix reduces affinity as well as specificity. We therefore find that RBM20 uses a coupled folding-binding mechanism by the C-terminal helix to specifically recognize the UCUU RNA motif.
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Affiliation(s)
| | - Cameron D Mackereth
- Univ. Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607 Pessac Cedex, France.,Inserm U1212, CNRS UMR5320, ARNA Laboratory, 146 rue Léo Saignat, 33076 Bordeaux Cedex, France
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