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Kurzlechner LM, Kishnani S, Chowdhury S, Atkins SL, Moya-Mendez ME, Parker LE, Rosamilia MB, Tadros HJ, Pace LA, Patel V, Chahal CAA, Landstrom AP. DiscoVari: A Web-Based Precision Medicine Tool for Predicting Variant Pathogenicity in Cardiomyopathy- and Channelopathy-Associated Genes. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2023; 16:317-327. [PMID: 37409478 PMCID: PMC10527712 DOI: 10.1161/circgen.122.003911] [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] [Received: 08/17/2022] [Accepted: 05/30/2023] [Indexed: 07/07/2023]
Abstract
BACKGROUND With genetic testing advancements, the burden of incidentally identified cardiac disease-associated gene variants is rising. These variants may carry a risk of sudden cardiac death, highlighting the need for accurate diagnostic interpretation. We sought to identify pathogenic hotspots in sudden cardiac death-associated genes using amino acid-level signal-to-noise (S:N) analysis and develop a web-based precision medicine tool, DiscoVari, to improve variant evaluation. METHODS The minor allele frequency of putatively pathogenic variants was derived from cohort-based cardiomyopathy and channelopathy studies in the literature. We normalized disease-associated minor allele frequencies to rare variants in an ostensibly healthy population (Genome Aggregation Database) to calculate amino acid-level S:N. Amino acids with S:N above the gene-specific threshold were defined as hotspots. DiscoVari was built using JavaScript ES6 and using open-source JavaScript library ReactJS, web development framework Next.js, and JavaScript runtime NodeJS. We validated the ability of DiscoVari to identify pathogenic variants using variants from ClinVar and individuals clinically evaluated at the Duke University Hospitals with cardiac genetic testing. RESULTS We developed DiscoVari as an internet-based tool for S:N-based variant hotspots. Upon validation, a higher proportion of ClinVar likely pathogenic/pathogenic variants localized to DiscoVari hotspots (43.1%) than likely benign/benign variants (17.8%; P<0.0001). Further, 75.3% of ClinVar variants reclassified to likely pathogenic/pathogenic were in hotspots, compared with 41.3% of those reclassified as variants of uncertain significance (P<0.0001) and 23.4% of those reclassified as likely benign/benign (P<0.0001). Of the clinical cohort variants, 73.1% of likely pathogenic/pathogenic were in hotspots, compared with 0.0% of likely benign/benign (P<0.01). CONCLUSIONS DiscoVari reliably identifies disease-susceptible amino acid residues to evaluate variants by searching amino acid-specific S:N ratios.
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Affiliation(s)
| | - Sujata Kishnani
- Dept of Pediatrics, Division of Pediatric Cardiology, Durham, NC
| | - Shawon Chowdhury
- Dept of Pediatrics, Division of Pediatric Cardiology, Durham, NC
| | - Sage L. Atkins
- Dept of Pediatrics, Division of Pediatric Cardiology, Durham, NC
| | | | - Lauren E. Parker
- Dept of Pediatrics, Division of Pediatric Cardiology, Durham, NC
| | | | - Hanna J. Tadros
- Dept of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Houston, TX
| | - Leslie A. Pace
- Dept of Pediatrics, Division of Pediatric Cardiology, Durham, NC
| | - Viraj Patel
- North West Thames Regional Genetics Service, St Mark’s Hospital, London, United Kingdom
| | - C. Anwar A. Chahal
- Center for Inherited Cardiovascular Diseases, WellSpan Health, Lancaster, PA
- Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom
- Cardiac Electrophysiology, Cardiovascular Division, Hospital of the Univ of Pennsylvania, Philadelphia, PA
- Dept of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | - Andrew P. Landstrom
- Dept of Pediatrics, Division of Pediatric Cardiology, Durham, NC
- Dept of Cell Biology, Duke Univ School of Medicine, Durham, NC
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Kucher AN, Valiakhmetov NR, Salakhov RR, Golubenko MV, Pavlyukova EN, Nazarenko MS. Phenotype variation of hypertrophic cardiomyopathy in carriers of the p.Arg870His pathogenic variant in the MYH7 gene. BULLETIN OF SIBERIAN MEDICINE 2022. [DOI: 10.20538/1682-0363-2022-3-205-216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The review analyzes variability of clinical manifestations of p.Arg870His in the MYH7 gene, which is repeatedly registered in patients with hypertrophic cardiomyopathy (HCM). The analysis involves the data from scientific publications obtained as a search result in the PubMed, СlinVar, and eLibrary.ru databases, as well as authors’ own results. A wide range of phenotypic manifestations have been revealed in carriers of p.Arg870His, from the asymptomatic to severe course, rapid progression, and early death. The review considers possible factors that modify the effect of the pathogenic variant (i.e. dosage of the pathogenic variant, the presence of other unfavorable genetic variants, etc.). The importance of accumulating information on the clinical features of HCM in the carriers of specific gene variants is emphasized in order to clarify their pathogenicity and to identify factors modifying the clinical outcome, which is important for the choice of the treatment strategy for HCM.
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Affiliation(s)
- A. N. Kucher
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences
| | - N. R. Valiakhmetov
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences
| | - R. R. Salakhov
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences; Siberian State Medical University
| | - M. V. Golubenko
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences
| | - E. N. Pavlyukova
- Cardiology Research Institute, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences
| | - M. S. Nazarenko
- Research Institute of Medical Genetics, Tomsk National Research Medical Center (NRMC), Russian Academy of Sciences; Siberian State Medical University
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Osten J, Mohebbi M, Uta P, Matinmehr F, Wang T, Kraft T, Amrute-Nayak M, Scholz T. Myosin essential light chain 1sa decelerates actin and thin filament gliding on β-myosin molecules. J Gen Physiol 2022; 154:213440. [PMID: 36053243 PMCID: PMC9441736 DOI: 10.1085/jgp.202213149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 08/05/2022] [Indexed: 11/20/2022] Open
Abstract
The β-myosin heavy chain expressed in ventricular myocardium and the myosin heavy chain (MyHC) in slow-twitch skeletal Musculus soleus (M. soleus) type-I fibers are both encoded by MYH7. Thus, these myosin molecules are deemed equivalent. However, some reports suggested variations in the light chain composition between M. soleus and ventricular myosin, which could influence functional parameters, such as maximum velocity of shortening. To test for functional differences of the actin gliding velocity on immobilized myosin molecules, we made use of in vitro motility assays. We found that ventricular myosin moved actin filaments with ∼0.9 µm/s significantly faster than M. soleus myosin (0.3 µm/s). Filaments prepared from isolated actin are not the native interaction partner of myosin and are believed to slow down movement. Yet, using native thin filaments purified from M. soleus or ventricular tissue, the gliding velocity of M. soleus and ventricular myosin remained significantly different. When comparing the light chain composition of ventricular and M. soleus β-myosin, a difference became evident. M. soleus myosin contains not only the "ventricular" essential light chain (ELC) MLC1sb/v, but also an additional longer and more positively charged MLC1sa. Moreover, we revealed that on a single muscle fiber level, a higher relative content of MLC1sa was associated with significantly slower actin gliding. We conclude that the ELC MLC1sa decelerates gliding velocity presumably by a decreased dissociation rate from actin associated with a higher actin affinity compared to MLC1sb/v. Such ELC/actin interactions might also be relevant in vivo as differences between M. soleus and ventricular myosin persisted when native thin filaments were used.
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Affiliation(s)
- Jennifer Osten
- Molecular and Cellular Physiology, Hannover Medical School, Hannover, Germany
| | - Maral Mohebbi
- Molecular and Cellular Physiology, Hannover Medical School, Hannover, Germany
| | - Petra Uta
- Molecular and Cellular Physiology, Hannover Medical School, Hannover, Germany
| | - Faramarz Matinmehr
- Molecular and Cellular Physiology, Hannover Medical School, Hannover, Germany
| | - Tianbang Wang
- Molecular and Cellular Physiology, Hannover Medical School, Hannover, Germany
| | - Theresia Kraft
- Molecular and Cellular Physiology, Hannover Medical School, Hannover, Germany
| | - Mamta Amrute-Nayak
- Molecular and Cellular Physiology, Hannover Medical School, Hannover, Germany
| | - Tim Scholz
- Molecular and Cellular Physiology, Hannover Medical School, Hannover, Germany,Correspondence to Tim Scholz:
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4
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Kurzlechner LM, Jones EG, Berkman AM, Tadros HJ, Rosenfeld JA, Yang Y, Tunuguntla H, Allen HD, Kim JJ, Landstrom AP. Signal-to-Noise Analysis Can Inform the Likelihood That Incidentally Identified Variants in Sarcomeric Genes Are Associated with Pediatric Cardiomyopathy. J Pers Med 2022; 12:733. [PMID: 35629155 PMCID: PMC9145017 DOI: 10.3390/jpm12050733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/06/2022] [Accepted: 04/20/2022] [Indexed: 02/01/2023] Open
Abstract
Background: Hypertrophic cardiomyopathy (HCM) is the most common heritable cardiomyopathy and can predispose individuals to sudden death. Most pediatric HCM patients host a known pathogenic variant in a sarcomeric gene. With the increase in exome sequencing (ES) in clinical settings, incidental variants in HCM-associated genes are being identified more frequently. Diagnostic interpretation of incidental variants is crucial to enhance clinical patient management. We sought to use amino acid-level signal-to-noise (S:N) analysis to establish pathogenic hotspots in sarcomeric HCM-associated genes as well as to refine the 2015 American College of Medical Genetics (ACMG) criteria to predict incidental variant pathogenicity. Methods and Results: Incidental variants in HCM genes (MYBPC3, MYH7, MYL2, MYL3, ACTC1, TPM1, TNNT2, TNNI3, and TNNC1) were obtained from a clinical ES referral database (Baylor Genetics) and compared to rare population variants (gnomAD) and variants from HCM literature cohort studies. A subset of the ES cohort was clinically evaluated at Texas Children’s Hospital. We compared the frequency of ES and HCM variants at specific amino acid locations in coding regions to rare variants (MAF < 0.0001) in gnomAD. S:N ratios were calculated at the gene- and amino acid-level to identify pathogenic hotspots. ES cohort variants were re-classified using ACMG criteria with S:N analysis as a correlate for PM1 criteria, which reduced the burden of variants of uncertain significance. In the clinical validation cohort, the majority of probands with cardiomyopathy or family history hosted likely pathogenic or pathogenic variants. Conclusions: Incidental variants in HCM-associated genes were common among clinical ES referrals, although the majority were not disease-associated. Leveraging amino acid-level S:N as a clinical tool may improve the diagnostic discriminatory ability of ACMG criteria by identifying pathogenic hotspots.
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Affiliation(s)
- Leonie M. Kurzlechner
- Division of Pediatric Cardiology, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA; (L.M.K.); (A.M.B.)
| | - Edward G. Jones
- Section of Pediatric Cardiology, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (E.G.J.); (H.J.T.); (H.T.); (H.D.A.); (J.J.K.)
| | - Amy M. Berkman
- Division of Pediatric Cardiology, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA; (L.M.K.); (A.M.B.)
| | - Hanna J. Tadros
- Section of Pediatric Cardiology, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (E.G.J.); (H.J.T.); (H.T.); (H.D.A.); (J.J.K.)
- Department of Pediatrics, University of Florida, Gainesville, FL 32611, USA
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor Genetics Laboratories, Baylor College of Medicine, Houston, TX 77030, USA; (J.A.R.); (Y.Y.)
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor Genetics Laboratories, Baylor College of Medicine, Houston, TX 77030, USA; (J.A.R.); (Y.Y.)
| | - Hari Tunuguntla
- Section of Pediatric Cardiology, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (E.G.J.); (H.J.T.); (H.T.); (H.D.A.); (J.J.K.)
| | - Hugh D. Allen
- Section of Pediatric Cardiology, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (E.G.J.); (H.J.T.); (H.T.); (H.D.A.); (J.J.K.)
| | - Jeffrey J. Kim
- Section of Pediatric Cardiology, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; (E.G.J.); (H.J.T.); (H.T.); (H.D.A.); (J.J.K.)
| | - Andrew P. Landstrom
- Division of Pediatric Cardiology, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA; (L.M.K.); (A.M.B.)
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
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Rani DS, Vijaya Kumar A, Nallari P, Sampathkumar K, Dhandapany PS, Narasimhan C, Rathinavel A, Thangaraj K. Novel Mutations in β-MYH7 Gene in Indian Patients With Dilated Cardiomyopathy. CJC Open 2022; 4:1-11. [PMID: 35072022 PMCID: PMC8767027 DOI: 10.1016/j.cjco.2021.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 07/30/2021] [Indexed: 11/29/2022] Open
Abstract
Background Methods Results Conclusions
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Affiliation(s)
- Deepa Selvi Rani
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
- Corresponding authors: Drs Deepa Selvi Rani and Kumarasamy Thangaraj, CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India. Tel.: +91-40-27192637.
| | - Archana Vijaya Kumar
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
- Department of Pathology and Immunology, University of Geneva Hospital, Geneva, Switzerland
| | | | - Katakam Sampathkumar
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | | | - Andiappan Rathinavel
- Department of Cardio-Thoracic Surgery, Government Rajaji Hospital, Madurai, India
| | - Kumarasamy Thangaraj
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Hyderabad, India
- Department of Biotechnology-Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
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6
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Myofibre Hyper-Contractility in Horses Expressing the Myosin Heavy Chain Myopathy Mutation, MYH1E321G. Cells 2021; 10:cells10123428. [PMID: 34943936 PMCID: PMC8699922 DOI: 10.3390/cells10123428] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 11/17/2022] Open
Abstract
Myosinopathies are defined as a group of muscle disorders characterized by mutations in genes encoding myosin heavy chains. Their exact molecular and cellular mechanisms remain unclear. In the present study, we have focused our attention on a MYH1-related E321G amino acid substitution within the head region of the type IIx skeletal myosin heavy chain, associated with clinical signs of atrophy, inflammation and/or profound rhabdomyolysis, known as equine myosin heavy chain myopathy. We performed Mant-ATP chase experiments together with force measurements on isolated IIx myofibres from control horses (MYH1E321G−/−) and Quarter Horses homozygous (MYH1E321G+/+) or heterozygous (MYH1E321G+/−) for the E321G mutation. The single residue replacement did not affect the relaxed conformations of myosin molecules. Nevertheless, it significantly increased its active behaviour as proven by the higher maximal force production and Ca2+ sensitivity for MYH1E321G+/+ in comparison with MYH1E321G+/− and MYH1E321G−/− horses. Altogether, these findings indicate that, in the presence of the E321G mutation, a molecular and cellular hyper-contractile phenotype occurs which could contribute to the development of the myosin heavy chain myopathy.
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7
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Vander Roest AS, Liu C, Morck MM, Kooiker KB, Jung G, Song D, Dawood A, Jhingran A, Pardon G, Ranjbarvaziri S, Fajardo G, Zhao M, Campbell KS, Pruitt BL, Spudich JA, Ruppel KM, Bernstein D. Hypertrophic cardiomyopathy β-cardiac myosin mutation (P710R) leads to hypercontractility by disrupting super relaxed state. Proc Natl Acad Sci U S A 2021. [PMID: 34117120 DOI: 10.1073/pnas.2025030118/suppl_file/pnas.2025030118.sm02.avi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited form of heart disease, associated with over 1,000 mutations, many in β-cardiac myosin (MYH7). Molecular studies of myosin with different HCM mutations have revealed a diversity of effects on ATPase and load-sensitive rate of detachment from actin. It has been difficult to predict how such diverse molecular effects combine to influence forces at the cellular level and further influence cellular phenotypes. This study focused on the P710R mutation that dramatically decreased in vitro motility velocity and actin-activated ATPase, in contrast to other MYH7 mutations. Optical trap measurements of single myosin molecules revealed that this mutation reduced the step size of the myosin motor and the load sensitivity of the actin detachment rate. Conversely, this mutation destabilized the super relaxed state in longer, two-headed myosin constructs, freeing more heads to generate force. Micropatterned human induced pluripotent derived stem cell (hiPSC)-cardiomyocytes CRISPR-edited with the P710R mutation produced significantly increased force (measured by traction force microscopy) compared with isogenic control cells. The P710R mutation also caused cardiomyocyte hypertrophy and cytoskeletal remodeling as measured by immunostaining and electron microscopy. Cellular hypertrophy was prevented in the P710R cells by inhibition of ERK or Akt. Finally, we used a computational model that integrated the measured molecular changes to predict the measured traction forces. These results confirm a key role for regulation of the super relaxed state in driving hypercontractility in HCM with the P710R mutation and demonstrate the value of a multiscale approach in revealing key mechanisms of disease.
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Affiliation(s)
- Alison Schroer Vander Roest
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Chao Liu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Makenna M Morck
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kristina Bezold Kooiker
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- School of Medicine, University of Washington, Seattle, WA 98109
| | - Gwanghyun Jung
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Dan Song
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Aminah Dawood
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Arnav Jhingran
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
| | - Gaspard Pardon
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Sara Ranjbarvaziri
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Giovanni Fajardo
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Mingming Zhao
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, KY 40536
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY 40536
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Mechanical and Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106
| | - James A Spudich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kathleen M Ruppel
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Bernstein
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304;
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
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8
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Vander Roest AS, Liu C, Morck MM, Kooiker KB, Jung G, Song D, Dawood A, Jhingran A, Pardon G, Ranjbarvaziri S, Fajardo G, Zhao M, Campbell KS, Pruitt BL, Spudich JA, Ruppel KM, Bernstein D. Hypertrophic cardiomyopathy β-cardiac myosin mutation (P710R) leads to hypercontractility by disrupting super relaxed state. Proc Natl Acad Sci U S A 2021; 118:e2025030118. [PMID: 34117120 PMCID: PMC8214707 DOI: 10.1073/pnas.2025030118] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited form of heart disease, associated with over 1,000 mutations, many in β-cardiac myosin (MYH7). Molecular studies of myosin with different HCM mutations have revealed a diversity of effects on ATPase and load-sensitive rate of detachment from actin. It has been difficult to predict how such diverse molecular effects combine to influence forces at the cellular level and further influence cellular phenotypes. This study focused on the P710R mutation that dramatically decreased in vitro motility velocity and actin-activated ATPase, in contrast to other MYH7 mutations. Optical trap measurements of single myosin molecules revealed that this mutation reduced the step size of the myosin motor and the load sensitivity of the actin detachment rate. Conversely, this mutation destabilized the super relaxed state in longer, two-headed myosin constructs, freeing more heads to generate force. Micropatterned human induced pluripotent derived stem cell (hiPSC)-cardiomyocytes CRISPR-edited with the P710R mutation produced significantly increased force (measured by traction force microscopy) compared with isogenic control cells. The P710R mutation also caused cardiomyocyte hypertrophy and cytoskeletal remodeling as measured by immunostaining and electron microscopy. Cellular hypertrophy was prevented in the P710R cells by inhibition of ERK or Akt. Finally, we used a computational model that integrated the measured molecular changes to predict the measured traction forces. These results confirm a key role for regulation of the super relaxed state in driving hypercontractility in HCM with the P710R mutation and demonstrate the value of a multiscale approach in revealing key mechanisms of disease.
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Affiliation(s)
- Alison Schroer Vander Roest
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Chao Liu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Makenna M Morck
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kristina Bezold Kooiker
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- School of Medicine, University of Washington, Seattle, WA 98109
| | - Gwanghyun Jung
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Dan Song
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Aminah Dawood
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Arnav Jhingran
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
| | - Gaspard Pardon
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Sara Ranjbarvaziri
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Giovanni Fajardo
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Mingming Zhao
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, KY 40536
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY 40536
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Mechanical and Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106
| | - James A Spudich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kathleen M Ruppel
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Bernstein
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304;
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
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Wu S, Li H, Wang L, Mak N, Wu X, Ge R, Sun F, Cheng CY. Motor Proteins and Spermatogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1288:131-159. [PMID: 34453735 DOI: 10.1007/978-3-030-77779-1_7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Unlike the intermediate filament- and septin-based cytoskeletons which are apolar structures, the microtubule (MT) and actin cytoskeletons are polarized structures in mammalian cells and tissues including the testis, most notable in Sertoli cells. In the testis, these cytoskeletons that stretch across the epithelium of seminiferous tubules and lay perpendicular to the basement membrane of tunica propria serve as tracks for corresponding motor proteins to support cellular cargo transport. These cargoes include residual bodies, phagosomes, endocytic vesicles and most notably developing spermatocytes and haploid spermatids which lack the ultrastructures of motile cells (e.g., lamellipodia, filopodia). As such, these developing germ cells require the corresponding motor proteins to facilitate their transport across the seminiferous epithelium during the epithelial cycle of spermatogenesis. Due to the polarized natures of these cytoskeletons with distinctive plus (+) and minus (-) end, directional cargo transport can take place based on the use of corresponding actin- or MT-based motor proteins. These include the MT-based minus (-) end directed motor proteins: dyneins, and the plus (+) end directed motor proteins: kinesins, as well as the actin-based motor proteins: myosins, many of which are plus (+) end directed but a few are also minus (-) end directed motor proteins. Recent studies have shown that these motor proteins are essential to support spermatogenesis. In this review, we briefly summarize and evaluate these recent findings so that this information will serve as a helpful guide for future studies and for planning functional experiments to better understand their role mechanistically in supporting spermatogenesis.
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Affiliation(s)
- Siwen Wu
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Zhejiang, China.,The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY, USA
| | - Huitao Li
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Zhejiang, China.,The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY, USA
| | - Lingling Wang
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Zhejiang, China.,The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY, USA.,Institute of Reproductive Medicine, Nantong University School of Medicine, Nantong, Jiangsu, China
| | - Nathan Mak
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY, USA
| | - Xiaolong Wu
- Institute of Reproductive Medicine, Nantong University School of Medicine, Nantong, Jiangsu, China
| | - Renshan Ge
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Zhejiang, China
| | - Fei Sun
- Sir Run Run Shaw Hospital (SRRSH), Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - C Yan Cheng
- Sir Run Run Shaw Hospital (SRRSH), Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
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10
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Fujino N, Hayashi K, Sakata K, Tada H, Nakanishi C, Tsuda T, Nomura A, Yoshida S, Sakamoto Y, Kato T, Furusho H, Kawashiri M, Takamura M. Transient swallowing-induced atrial tachycardia in a patient with genotyped hypertrophic cardiomyopathy. Clin Case Rep 2020; 8:1809-1813. [PMID: 32983501 PMCID: PMC7495763 DOI: 10.1002/ccr3.3015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/07/2020] [Accepted: 05/15/2020] [Indexed: 11/11/2022] Open
Abstract
Most cases of swallowing-induced atrial tachycardia require radiofrequency catheter ablation for a permanent cure; however, the arrhythmia subsided after temporary prescription of verapamil in a patient with genotyped hypertrophic cardiomyopathy.
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Affiliation(s)
- Noboru Fujino
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Kenshi Hayashi
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Kenji Sakata
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Hayato Tada
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Chiaki Nakanishi
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Toyonobu Tsuda
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Akihiro Nomura
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Shohei Yoshida
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | | | - Takeshi Kato
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Hiroshi Furusho
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Masa‐aki Kawashiri
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
| | - Masayuki Takamura
- Department of Cardiovascular MedicineKanazawa University Graduate School of Medical SciencesKanazawaJapan
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11
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Hirono K, Hata Y, Miyao N, Okabe M, Takarada S, Nakaoka H, Ibuki K, Ozawa S, Yoshimura N, Nishida N, Ichida F. Left Ventricular Noncompaction and Congenital Heart Disease Increases the Risk of Congestive Heart Failure. J Clin Med 2020; 9:jcm9030785. [PMID: 32183154 PMCID: PMC7141335 DOI: 10.3390/jcm9030785] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 02/28/2020] [Accepted: 03/09/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Left ventricular noncompaction (LVNC) is a hereditary cardiomyopathy that is associated with high morbidity and mortality rates. Recently, LVNC was classified into several phenotypes including congenital heart disease (CHD). However, although LVNC and CHD are frequently observed, the role and clinical significance of genetics in these cardiomyopathies has not been fully evaluated. Therefore, we aimed to evaluate the impact on the perioperative outcomes of children with concomitant LVNC and CHD using next-generation sequencing (NGS). METHODS From May 2000 to August 2018, 53 Japanese probands with LVNC (25 males and 28 females) were enrolled and we screened 182 cardiomyopathy-associated genes in these patients using NGS. RESULTS The age at diagnosis of the enrolled patients ranged from 0 to 14 years (median: 0.3 months). A total of 23 patients (43.4%) were diagnosed with heart failure, 14 with heart murmur (26.4%), and 6 with cyanosis (11.3%). During the observation period, 31 patients (58.5%) experienced heart failure and 13 (24.5%) developed arrhythmias such as ventricular tachycardia, supraventricular tachycardia, and atrioventricular block. Moreover, 29 patients (54.7%) had ventricular septal defects (VSDs), 17 (32.1%) had atrial septal defects, 10 had patent ductus arteriosus (PDA), and 7 (13.2%) had Ebstein's anomaly and double outlet right ventricle. Among the included patients, 30 underwent surgery, 19 underwent biventricular repair, and 2 underwent pulmonary artery banding, bilateral pulmonary artery banding, and PDA ligation. Overall, 30 genetic variants were identified in 28 patients with LVNC and CHD. Eight variants were detected in MYH7 and two in TPM1. Echocardiography showed lower ejection fractions and more thickened trabeculations in the left ventricle in patients with LVNC and CHD than in age-matched patients with VSDs. During follow-up, 4 patients died and the condition of 8 worsened postoperatively. The multivariable proportional hazards model showed that heart failure, LV ejection fraction of < 24%, LV end-diastolic diameter z-score of > 8.56, and noncompacted-to-compacted ratio of the left ventricular apex of > 8.33 at the last visit were risk factors for survival. CONCLUSIONS LVNC and CHD are frequently associated with genetic abnormalities. Knowledge of the association between CHD and LVNC is important for the awareness of clinical implications during the preoperative and postoperative periods to identify the populations who are at an increased risk of additional morbidity.
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Affiliation(s)
- Keiichi Hirono
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
- Correspondence: ; Tel.: +81-76-434-7313; Fax: +81-76-434-5029
| | - Yukiko Hata
- Legal Medicine, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (Y.H.); (N.N.)
| | - Nariaki Miyao
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Mako Okabe
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Shinya Takarada
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Hideyuki Nakaoka
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Keijiro Ibuki
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Sayaka Ozawa
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Naoki Yoshimura
- First Department of Surgery, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan;
| | - Naoki Nishida
- Legal Medicine, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (Y.H.); (N.N.)
| | - Fukiko Ichida
- Department of Pediatrics, International University of Health and Welfare, Tokyo 107-0052, Japan;
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12
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Abstract
BACKGROUND Hypertrophic cardiomyopathy is an autosomal dominant hereditary disease characterised by left ventricular asymmetry hypertrophy. However, our knowledge of the genetic background in hypertrophic cardiomyopathy cases is limited. Here, we aimed to evaluate pathogenic gene mutations in a family with high-risk hypertrophic cardiomyopathy and analyse the genotype/phenotype relationships in this family. METHODS The proband, her parents, and her niece underwent whole-exome sequencing, and the genotypes of family members were identified using Sanger sequencing. mRNA expression was detected using reverse transcription sequencing. Structural impairments were predicted by homologous modelling. A family survey was conducted for patients with positive results to obtain information on general clinical symptoms, electrocardiography, ambulatory electrocardiography, echocardiography, and 3.0T cardiac magnetic resonance findings. Regular follow-up was performed for up to 6 months. RESULTS Five family members, including the proband, carried a cleavage site mutation in the MYBPC3 gene (c.2737+1 (IVS26) G>T), causing exon 26 of the MYBPC3 gene transcript to be skipped and leading to truncation of cardiac myosin-binding protein C. Family survey showed that the earliest onset age was 13 years old, and three people had died suddenly at less than 40 years old. Three pathogenic gene carriers were diagnosed with hypertrophic cardiomyopathy, and all showed severe ventricular septal hypertrophy. CONCLUSION The c.2737+1 (IVS26) G>T mutation in the MYBPC3 gene led to exon 26 skipping, thereby affecting the structure and function of cardiac myosin-binding protein C and leading to severe ventricular hypertrophy and sudden death.
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13
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Neural/Bayes network predictor for inheritable cardiac disease pathogenicity and phenotype. J Mol Cell Cardiol 2018; 119:19-27. [PMID: 29654880 DOI: 10.1016/j.yjmcc.2018.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 04/03/2018] [Accepted: 04/09/2018] [Indexed: 11/23/2022]
Abstract
The cardiac muscle sarcomere contains multiple proteins contributing to contraction energy transduction and its regulation during a heartbeat. Inheritable heart disease mutants affect most of them but none more frequently than the ventricular myosin motor and cardiac myosin binding protein c (mybpc3). These co-localizing proteins have mybpc3 playing a regulatory role to the energy transducing motor. Residue substitution and functional domain assignment of each mutation in the protein sequence decides, under the direction of a sensible disease model, phenotype and pathogenicity. The unknown model mechanism is decided here using a method combing neural and Bayes networks. Missense single nucleotide polymorphisms (SNPs) are clues for the disease mechanism summarized in an extensive database collecting mutant sequence location and residue substitution as independent variables that imply the dependent disease phenotype and pathogenicity characteristics in 4 dimensional data points (4ddps). The SNP database contains entries with the majority having one or both dependent data entries unfulfilled. A neural network relating causes (mutant residue location and substitution) and effects (phenotype and pathogenicity) is trained, validated, and optimized using fulfilled 4ddps. It then predicts unfulfilled 4ddps providing the implicit disease model. A discrete Bayes network interprets fulfilled and predicted 4ddps with conditional probabilities for phenotype and pathogenicity given mutation location and residue substitution thus relating the neural network implicit model to explicit features of the motor and mybpc3 sequence and structural domains. Neural/Bayes network forecasting automates disease mechanism modeling by leveraging the world wide human missense SNP database that is in place and expanding.
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14
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Zigova M, Bernasovska J, Boronova I, Mydlarova Blascakova M, Kmec J. Finding the candidate sequence variants for diagnosis of hypertrophic cardiomyopathy in East Slovak patients. J Clin Lab Anal 2018; 32. [DOI: 10.1002/jcla.22303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 07/02/2017] [Indexed: 11/07/2022] Open
Affiliation(s)
- Michaela Zigova
- Department of Biology; Faculty of Humanities and Natural Sciences; University of Presov; Presov Slovakia
| | - Jarmila Bernasovska
- Department of Biology; Faculty of Humanities and Natural Sciences; University of Presov; Presov Slovakia
| | - Iveta Boronova
- Department of Biology; Faculty of Humanities and Natural Sciences; University of Presov; Presov Slovakia
| | - Marta Mydlarova Blascakova
- Department of Biology; Faculty of Humanities and Natural Sciences; University of Presov; Presov Slovakia
| | - Jan Kmec
- Department of Urgent Health Care; Faculty of Health Care; University of Presov; Presov Slovakia
- Cardiocentre; Faculty Hospital of J.A. Reiman; Presov Slovakia
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15
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Alamo L, Ware JS, Pinto A, Gillilan RE, Seidman JG, Seidman CE, Padrón R. Effects of myosin variants on interacting-heads motif explain distinct hypertrophic and dilated cardiomyopathy phenotypes. eLife 2017; 6:e24634. [PMID: 28606303 PMCID: PMC5469618 DOI: 10.7554/elife.24634] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 05/05/2017] [Indexed: 12/12/2022] Open
Abstract
Cardiac β-myosin variants cause hypertrophic (HCM) or dilated (DCM) cardiomyopathy by disrupting sarcomere contraction and relaxation. The locations of variants on isolated myosin head structures predict contractility effects but not the prominent relaxation and energetic deficits that characterize HCM. During relaxation, pairs of myosins form interacting-heads motif (IHM) structures that with other sarcomere proteins establish an energy-saving, super-relaxed (SRX) state. Using a human β-cardiac myosin IHM quasi-atomic model, we defined interactions sites between adjacent myosin heads and associated protein partners, and then analyzed rare variants from 6112 HCM and 1315 DCM patients and 33,370 ExAC controls. HCM variants, 72% that changed electrostatic charges, disproportionately altered IHM interaction residues (expected 23%; HCM 54%, p=2.6×10-19; DCM 26%, p=0.66; controls 20%, p=0.23). HCM variant locations predict impaired IHM formation and stability, and attenuation of the SRX state - accounting for altered contractility, reduced diastolic relaxation, and increased energy consumption, that fully characterizes HCM pathogenesis.
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Affiliation(s)
- Lorenzo Alamo
- Centro de Biología Estructural, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - James S Ware
- National Heart and Lung Institute and MRC London Institute for Medical Sciences, Imperial College London, London, United Kingdom
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust and Imperial College London, London, United Kingdom
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Antonio Pinto
- Centro de Biología Estructural, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Richard E Gillilan
- Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source, Ithaca, United States
| | | | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, United States
- Cardiovascular Division, Brigham and Women’s Hospital and Howard Hughes Medical Institute, Boston, United States
| | - Raúl Padrón
- Centro de Biología Estructural, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
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16
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Silva CT, Zorkoltseva IV, Amin N, Demirkan A, van Leeuwen EM, Kors JA, van den Berg M, Stricker BH, Uitterlinden AG, Kirichenko AV, Witteman JCM, Willemsen R, Oostra BA, Axenovich TI, van Duijn CM, Isaacs A. A Combined Linkage and Exome Sequencing Analysis for Electrocardiogram Parameters in the Erasmus Rucphen Family Study. Front Genet 2016; 7:190. [PMID: 27877193 PMCID: PMC5099142 DOI: 10.3389/fgene.2016.00190] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 10/11/2016] [Indexed: 12/30/2022] Open
Abstract
Electrocardiogram (ECG) measurements play a key role in the diagnosis and prediction of cardiac arrhythmias and sudden cardiac death. ECG parameters, such as the PR, QRS, and QT intervals, are known to be heritable and genome-wide association studies of these phenotypes have been successful in identifying common variants; however, a large proportion of the genetic variability of these traits remains to be elucidated. The aim of this study was to discover loci potentially harboring rare variants utilizing variance component linkage analysis in 1547 individuals from a large family-based study, the Erasmus Rucphen Family Study (ERF). Linked regions were further explored using exome sequencing. Five suggestive linkage peaks were identified: two for QT interval (1q24, LOD = 2.63; 2q34, LOD = 2.05), one for QRS interval (1p35, LOD = 2.52) and two for PR interval (9p22, LOD = 2.20; 14q11, LOD = 2.29). Fine-mapping using exome sequence data identified a C > G missense variant (c.713C > G, p.Ser238Cys) in the FCRL2 gene associated with QT (rs74608430; P = 2.8 × 10-4, minor allele frequency = 0.019). Heritability analysis demonstrated that the SNP explained 2.42% of the trait’s genetic variability in ERF (P = 0.02). Pathway analysis suggested that the gene is involved in cytosolic Ca2+ levels (P = 3.3 × 10-3) and AMPK stimulated fatty acid oxidation in muscle (P = 4.1 × 10-3). Look-ups in bioinformatics resources showed that expression of FCRL2 is associated with ARHGAP24 and SETBP1 expression. This finding was not replicated in the Rotterdam study. Combining the bioinformatics information with the association and linkage analyses, FCRL2 emerges as a strong candidate gene for QT interval.
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Affiliation(s)
- Claudia T Silva
- Genetic Epidemiology Unit, Department of Epidemiology, Erasmus University Medical CenterRotterdam, Netherlands; Doctoral Program in Biomedical Sciences, Universidad del RosarioBogotá, Colombia; GENIUROS Group, Genetics and Genomics Research Center CIGGUR, School of Medicine and Health Sciences, Universidad del RosarioBogotá, Colombia
| | - Irina V Zorkoltseva
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences Novosibirsk, Russia
| | - Najaf Amin
- Genetic Epidemiology Unit, Department of Epidemiology, Erasmus University Medical Center Rotterdam, Netherlands
| | - Ayşe Demirkan
- Genetic Epidemiology Unit, Department of Epidemiology, Erasmus University Medical CenterRotterdam, Netherlands; Department of Human Genetics, Leiden University Medical CenterLeiden, Netherlands
| | - Elisabeth M van Leeuwen
- Genetic Epidemiology Unit, Department of Epidemiology, Erasmus University Medical Center Rotterdam, Netherlands
| | - Jan A Kors
- Department of Medical Informatics, Erasmus University Medical Center Rotterdam, Netherlands
| | - Marten van den Berg
- Department of Medical Informatics, Erasmus University Medical Center Rotterdam, Netherlands
| | - Bruno H Stricker
- Department of Epidemiology, Erasmus University Medical CenterRotterdam, Netherlands; Department of Internal Medicine, Erasmus University Medical CenterRotterdam, Netherlands; Inspectorate of Health CareThe Hague, Netherlands
| | - André G Uitterlinden
- Department of Internal Medicine, Erasmus University Medical Center Rotterdam, Netherlands
| | - Anatoly V Kirichenko
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences Novosibirsk, Russia
| | | | - Rob Willemsen
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Netherlands
| | - Ben A Oostra
- Genetic Epidemiology Unit, Department of Epidemiology, Erasmus University Medical CenterRotterdam, Netherlands; Center for Medical Systems BiologyLeiden, Netherlands
| | - Tatiana I Axenovich
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences Novosibirsk, Russia
| | - Cornelia M van Duijn
- Genetic Epidemiology Unit, Department of Epidemiology, Erasmus University Medical CenterRotterdam, Netherlands; Center for Medical Systems BiologyLeiden, Netherlands
| | - Aaron Isaacs
- Genetic Epidemiology Unit, Department of Epidemiology, Erasmus University Medical CenterRotterdam, Netherlands; Center for Medical Systems BiologyLeiden, Netherlands
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17
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Fiorillo C, Astrea G, Savarese M, Cassandrini D, Brisca G, Trucco F, Pedemonte M, Trovato R, Ruggiero L, Vercelli L, D'Amico A, Tasca G, Pane M, Fanin M, Bello L, Broda P, Musumeci O, Rodolico C, Messina S, Vita GL, Sframeli M, Gibertini S, Morandi L, Mora M, Maggi L, Petrucci A, Massa R, Grandis M, Toscano A, Pegoraro E, Mercuri E, Bertini E, Mongini T, Santoro L, Nigro V, Minetti C, Santorelli FM, Bruno C. MYH7-related myopathies: clinical, histopathological and imaging findings in a cohort of Italian patients. Orphanet J Rare Dis 2016; 11:91. [PMID: 27387980 PMCID: PMC4936326 DOI: 10.1186/s13023-016-0476-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/22/2016] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Myosin heavy chain 7 (MYH7)-related myopathies are emerging as an important group of muscle diseases of childhood and adulthood, with variable clinical and histopathological expression depending on the type and location of the mutation. Mutations in the head and neck domains are a well-established cause of hypertrophic cardiomyopathy whereas mutation in the distal regions have been associated with a range of skeletal myopathies with or without cardiac involvement, including Laing distal myopathy and Myosin storage myopathy. Recently the spectrum of clinical phenotypes associated with mutations in MYH7 has increased, blurring this scheme and adding further phenotypes to the list. A broader disease spectrum could lead to misdiagnosis of different congenital myopathies, neurogenic atrophy and other neuromuscular conditions. RESULTS As a result of a multicenter Italian study we collected clinical, histopathological and imaging data from a population of 21 cases from 15 families, carrying reported or novel mutations in MYH7. Patients displayed a variable phenotype including atypical pictures, as dropped head and bent spine, which cannot be classified in previously described groups. Half of the patients showed congenital or early infantile weakness with predominant distal weakness. Conversely, patients with later onset present prevalent proximal weakness. Seven patients were also affected by cardiomyopathy mostly in the form of non-compacted left ventricle. Muscle biopsy was consistent with minicores myopathy in numerous cases. Muscle MRI was meaningful in delineating a shared pattern of selective involvement of tibialis anterior muscles, with relative sparing of quadriceps. CONCLUSION This work adds to the genotype-phenotype correlation of MYH7-relatedmyopathies confirming the complexity of the disorder.
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Affiliation(s)
- C Fiorillo
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy. .,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy.
| | - G Astrea
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - M Savarese
- Telethon Institute of Genetics and Medicine, Naples, Italy
| | - D Cassandrini
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - G Brisca
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy.,Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto Giannina Gaslini, Genoa, Italy
| | - F Trucco
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - M Pedemonte
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - R Trovato
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - L Ruggiero
- Department of Neurosciences and Reproductive and Odontostomatologic Sciences, University Federico II, Naples, Italy
| | - L Vercelli
- Department of Neurosciences "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - A D'Amico
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - G Tasca
- Don Carlo Gnocchi ONLUS Foundation, Rome, Italy
| | - M Pane
- Department of Paediatric Neurology, Catholic University, Rome, Italy
| | - M Fanin
- Department of Neurosciences, University of Padua, Padua, Italy
| | - L Bello
- Department of Neurosciences, University of Padua, Padua, Italy
| | - P Broda
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - O Musumeci
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - C Rodolico
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - S Messina
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - G L Vita
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - M Sframeli
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - S Gibertini
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - L Morandi
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - M Mora
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - L Maggi
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - A Petrucci
- Center for Neuromuscular and Neurological Rare Diseases, S. Camillo-Forlanini Hospital, Rome, Italy
| | - R Massa
- Department of Systems Medicine (Neurology), University of Tor Vergata, Rome, Italy
| | - M Grandis
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy
| | - A Toscano
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - E Pegoraro
- Department of Neurosciences, University of Padua, Padua, Italy
| | - E Mercuri
- Department of Paediatric Neurology, Catholic University, Rome, Italy
| | - E Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - T Mongini
- Department of Neurosciences "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - L Santoro
- Department of Neurosciences and Reproductive and Odontostomatologic Sciences, University Federico II, Naples, Italy
| | - V Nigro
- Telethon Institute of Genetics and Medicine, Naples, Italy
| | - C Minetti
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy
| | - F M Santorelli
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - C Bruno
- Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto Giannina Gaslini, Genoa, Italy
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18
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Multidimensional structure-function relationships in human β-cardiac myosin from population-scale genetic variation. Proc Natl Acad Sci U S A 2016; 113:6701-6. [PMID: 27247418 DOI: 10.1073/pnas.1606950113] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myosin motors are the fundamental force-generating elements of muscle contraction. Variation in the human β-cardiac myosin heavy chain gene (MYH7) can lead to hypertrophic cardiomyopathy (HCM), a heritable disease characterized by cardiac hypertrophy, heart failure, and sudden cardiac death. How specific myosin variants alter motor function or clinical expression of disease remains incompletely understood. Here, we combine structural models of myosin from multiple stages of its chemomechanical cycle, exome sequencing data from two population cohorts of 60,706 and 42,930 individuals, and genetic and phenotypic data from 2,913 patients with HCM to identify regions of disease enrichment within β-cardiac myosin. We first developed computational models of the human β-cardiac myosin protein before and after the myosin power stroke. Then, using a spatial scan statistic modified to analyze genetic variation in protein 3D space, we found significant enrichment of disease-associated variants in the converter, a kinetic domain that transduces force from the catalytic domain to the lever arm to accomplish the power stroke. Focusing our analysis on surface-exposed residues, we identified a larger region significantly enriched for disease-associated variants that contains both the converter domain and residues on a single flat surface on the myosin head described as the myosin mesa. Notably, patients with HCM with variants in the enriched regions have earlier disease onset than patients who have HCM with variants elsewhere. Our study provides a model for integrating protein structure, large-scale genetic sequencing, and detailed phenotypic data to reveal insight into time-shifted protein structures and genetic disease.
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Hill TW, Jackson-Hayes L, Wang X, Hoge BL. A mutation in the converter subdomain of Aspergillus nidulans MyoB blocks constriction of the actomyosin ring in cytokinesis. Fungal Genet Biol 2015; 75:72-83. [PMID: 25645080 DOI: 10.1016/j.fgb.2015.01.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 01/11/2015] [Accepted: 01/22/2015] [Indexed: 12/17/2022]
Abstract
We have identified a mutant allele of the Aspergillus nidulans homologue of myosin II (myoB; AN4706), which prevents normal septum formation. This is the first reported myosin II mutation in a filamentous fungus. Strains expressing the myoB(G843D) allele produce mainly aberrant septa at 30 °C and are completely aseptate at temperatures above 37 °C. Conidium formation is greatly reduced at 30 °C and progressively impaired with increasing temperature. Sequencing of the myoB(G843D) allele identified a point mutation predicted to result in a glycine-to-aspartate amino acid substitution at residue 843 in the myosin II converter domain. This residue is conserved in all fungal, plant, and animal myosin sequences that we have examined. The mutation does not prevent localization of the myoB(G843D) gene product to contractile rings, but it does block ring constriction. MyoB(G843D) rings at sites of abortive septation disassemble after an extended period and dissipate into the cytoplasm. During contractile ring formation, both wild type and mutant MyoB::GFP colocalize with actin--an association that begins at the pre-ring "string" stage. Down-regulation of wild-type myoB expression under control of the alcA promoter blocks septation but does not prevent actin from aggregating at putative septation sites--the actin rings, however, do not fully coalesce. Both septation and targeting of MyoB are blocked by disruption of filamentous actin using latrunculin B. We propose a model in which myosin assembly at septation sites depends upon the presence of F-actin, but assembly of the actin component of contractile rings depends upon normal levels of myosin only for the final stages of ring compaction.
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Affiliation(s)
- Terry W Hill
- Department of Biology, Rhodes College, Memphis, TN 38112, USA.
| | | | - Xiao Wang
- Department of Biology, Rhodes College, Memphis, TN 38112, USA
| | - Brianna L Hoge
- Department of Biology, Rhodes College, Memphis, TN 38112, USA
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20
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Guo Q, Xu Y, Wang X, Guo Y, Xu R, Sun K, Chen S. Exome sequencing identifies a novel MYH7 p.G407C mutation responsible for familial hypertrophic cardiomyopathy. DNA Cell Biol 2014; 33:699-704. [PMID: 24963656 DOI: 10.1089/dna.2014.2483] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM), characterized by myocardial hypertrophy, is the most common cause of sudden cardiac arrest in young individuals. More than 270 mutations have been found to be responsible for familial HCM to date; mutations in MYH7, which encodes the β-myosin heavy chain (β-MHC) and MYBPC3, which encodes the myosin binding protein C, are seen most often. This study aimed to screen a pathogenic mutation causing HCM in a large family and assess its possible impact on the function of the specific protein. Exome sequencing was applied in the proband for searching a novel mutation; segments bearing the specific mutation were analyzed by polymerase chain reaction and direct sequencing. A novel p.G407C mutation in the β-MHC gene (MYH7) was identified to be responsible for familial HCM in this family. The mutation may cause damage to the second structure of the protein despite the fact that patients bearing the mutation may have a relatively benign prognosis in this family. The clinical details of the p.G407C mutation are described for the first time in this study. Our report shows a good genotype-phenotype consistency and makes it possible for genetic counseling in this family.
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Affiliation(s)
- Qianqian Guo
- 1 Department of Pediatric Cardiovascular, Xinhua Hospital Affiliated to Medical School of Shanghai Jiaotong University , Shanghai, People's Republic of China
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21
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Witjas-Paalberends ER, Ferrara C, Scellini B, Piroddi N, Montag J, Tesi C, Stienen GJM, Michels M, Ho CY, Kraft T, Poggesi C, van der Velden J. Faster cross-bridge detachment and increased tension cost in human hypertrophic cardiomyopathy with the R403Q MYH7 mutation. J Physiol 2014; 592:3257-72. [PMID: 24928957 DOI: 10.1113/jphysiol.2014.274571] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The first mutation associated with hypertrophic cardiomyopathy (HCM) is the R403Q mutation in the gene encoding β-myosin heavy chain (β-MyHC). R403Q locates in the globular head of myosin (S1), responsible for interaction with actin, and thus motor function of myosin. Increased cross-bridge relaxation kinetics caused by the R403Q mutation might underlie increased energetic cost of tension generation; however, direct evidence is absent. Here we studied to what extent cross-bridge kinetics and energetics are related in single cardiac myofibrils and multicellular cardiac muscle strips of three HCM patients with the R403Q mutation and nine sarcomere mutation-negative HCM patients (HCMsmn). Expression of R403Q was on average 41 ± 4% of total MYH7 mRNA. Cross-bridge slow relaxation kinetics in single R403Q myofibrils was significantly higher (P < 0.0001) than in HCMsmn myofibrils (0.47 ± 0.02 and 0.30 ± 0.02 s(-1), respectively). Moreover, compared to HCMsmn, tension cost was significantly higher in the muscle strips of the three R403Q patients (2.93 ± 0.25 and 1.78 ± 0.10 μmol l(-1) s(-1) kN(-1) m(-2), respectively) which showed a positive linear correlation with relaxation kinetics in the corresponding myofibril preparations. This correlation suggests that faster cross-bridge relaxation kinetics results in an increase in energetic cost of tension generation in human HCM with the R403Q mutation compared to HCMsmn. Therefore, increased tension cost might contribute to HCM disease in patients carrying the R403Q mutation.
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Affiliation(s)
| | - Claudia Ferrara
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Judith Montag
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Ger J M Stienen
- Department of Physiology, VU University Medical Centre, Amsterdam, The Netherlands Department of Physics and Astronomy, VU University, Amsterdam, The Netherlands
| | - Michelle Michels
- Thorax Centre, Cardiology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Carolyn Y Ho
- Brigham and Women's Hospital, Cardiology, Boston, USA
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Jolanda van der Velden
- Department of Physiology, VU University Medical Centre, Amsterdam, The Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
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22
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Sequeira V, Nijenkamp LLAM, Regan JA, van der Velden J. The physiological role of cardiac cytoskeleton and its alterations in heart failure. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:700-22. [PMID: 23860255 DOI: 10.1016/j.bbamem.2013.07.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/01/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
Cardiac muscle cells are equipped with specialized biochemical machineries for the rapid generation of force and movement central to the work generated by the heart. During each heart beat cardiac muscle cells perceive and experience changes in length and load, which reflect one of the fundamental principles of physiology known as the Frank-Starling law of the heart. Cardiac muscle cells are unique mechanical stretch sensors that allow the heart to increase cardiac output, and adjust it to new physiological and pathological situations. In the present review we discuss the mechano-sensory role of the cytoskeletal proteins with respect to their tight interaction with the sarcolemma and extracellular matrix. The role of contractile thick and thin filament proteins, the elastic protein titin, and their anchorage at the Z-disc and M-band, with associated proteins are reviewed in physiologic and pathologic conditions leading to heart failure. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé
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Affiliation(s)
- Vasco Sequeira
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Louise L A M Nijenkamp
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Jessica A Regan
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; Department of Physiology, Molecular Cardiovascular Research Program, Sarver Heart Center, University of Arizona, Tucson, AZ 85724, USA
| | - Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; ICIN-Netherlands Heart Institute, The Netherlands.
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23
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Lindqvist J, Iwamoto H, Blanco G, Ochala J. The fraction of strongly bound cross-bridges is increased in mice that carry the myopathy-linked myosin heavy chain mutation MYH4L342Q. Dis Model Mech 2013; 6:834-40. [PMID: 23335206 PMCID: PMC3634666 DOI: 10.1242/dmm.011155] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 01/10/2013] [Indexed: 12/23/2022] Open
Abstract
Myosinopathies have emerged as a new group of diseases and are caused by mutations in genes encoding myosin heavy chain (MyHC) isoforms. One major hallmark of these diseases is skeletal muscle weakness or paralysis, but the underlying molecular mechanisms remain unclear. Here, we have undertaken a detailed functional study of muscle fibers from Myh4(arl) mice, which carry a mutation that provokes an L342Q change within the catalytic domain of the type IIb skeletal muscle myosin protein MYH4. Because homozygous animals develop rapid muscle-structure disruption and lower-limb paralysis, they must be killed by postnatal day 13, so all experiments were performed using skeletal muscles from adult heterozygous animals (Myh4(arl)/+). Myh4(arl)/+ mice contain MYH4(L342Q) expressed at 7% of the levels of the wild-type (WT) protein, and are overtly and histologically normal. However, mechanical and X-ray diffraction pattern analyses of single membrane-permeabilized fibers revealed, upon maximal Ca(2+) activation, higher stiffness as well as altered meridional and equatorial reflections in Myh4(arl)/+ mice when compared with age-matched WT animals. Under rigor conditions, by contrast, no difference was observed between Myh4(arl)/+ and WT mice. Altogether, these findings prove that, in adult MYH4(L342Q) heterozygous mice, the transition from weak to strong myosin cross-bridge binding is facilitated, increasing the number of strongly attached myosin heads, thus enhancing force production. These changes are predictably exacerbated in the type IIb fibers of homozygous mice, in which the embryonic myosin isoform is fully replaced by MYH4(L342Q), leading to a hypercontraction, muscle-structure disruption and lower-limb paralysis. Overall, these findings provide important insights into the molecular pathogenesis of skeletal myosinopathies.
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Affiliation(s)
- Johan Lindqvist
- Department of Neuroscience, Uppsala University, Uppsala 751 85, Sweden.
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24
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Sequeira V, Wijnker PJM, Nijenkamp LLAM, Kuster DWD, Najafi A, Witjas-Paalberends ER, Regan JA, Boontje N, Ten Cate FJ, Germans T, Carrier L, Sadayappan S, van Slegtenhorst MA, Zaremba R, Foster DB, Murphy AM, Poggesi C, Dos Remedios C, Stienen GJM, Ho CY, Michels M, van der Velden J. Perturbed length-dependent activation in human hypertrophic cardiomyopathy with missense sarcomeric gene mutations. Circ Res 2013; 112:1491-505. [PMID: 23508784 DOI: 10.1161/circresaha.111.300436] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE High-myofilament Ca(2+) sensitivity has been proposed as a trigger of disease pathogenesis in familial hypertrophic cardiomyopathy (HCM) on the basis of in vitro and transgenic mice studies. However, myofilament Ca(2+) sensitivity depends on protein phosphorylation and muscle length, and at present, data in humans are scarce. OBJECTIVE To investigate whether high myofilament Ca(2+) sensitivity and perturbed length-dependent activation are characteristics for human HCM with mutations in thick and thin filament proteins. METHODS AND RESULTS Cardiac samples from patients with HCM harboring mutations in genes encoding thick (MYH7, MYBPC3) and thin (TNNT2, TNNI3, TPM1) filament proteins were compared with sarcomere mutation-negative HCM and nonfailing donors. Cardiomyocyte force measurements showed higher myofilament Ca(2+) sensitivity in all HCM samples and low phosphorylation of protein kinase A (PKA) targets compared with donors. After exogenous PKA treatment, myofilament Ca(2+) sensitivity was similar (MYBPC3mut, TPM1mut, sarcomere mutation-negative HCM), higher (MYH7mut, TNNT2mut), or even significantly lower (TNNI3mut) compared with donors. Length-dependent activation was significantly smaller in all HCM than in donor samples. PKA treatment increased phosphorylation of PKA-targets in HCM myocardium and normalized length-dependent activation to donor values in sarcomere mutation-negative HCM and HCM with truncating MYBPC3 mutations but not in HCM with missense mutations. Replacement of mutant by wild-type troponin in TNNT2mut and TNNI3mut corrected length-dependent activation to donor values. CONCLUSIONS High-myofilament Ca(2+) sensitivity is a common characteristic of human HCM and partly reflects hypophosphorylation of PKA targets compared with donors. Length-dependent sarcomere activation is perturbed by missense mutations, possibly via posttranslational modifications other than PKA hypophosphorylation or altered protein-protein interactions, and represents a common pathomechanism in HCM.
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Affiliation(s)
- Vasco Sequeira
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, the Netherlands.
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Murgiano L, Tammen I, Harlizius B, Drögemüller C. A de novo germline mutation in MYH7 causes a progressive dominant myopathy in pigs. BMC Genet 2012; 13:99. [PMID: 23153285 PMCID: PMC3542579 DOI: 10.1186/1471-2156-13-99] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 10/25/2012] [Indexed: 11/20/2022] Open
Abstract
Background About 9% of the offspring of a clinically healthy Piétrain boar named ‘Campus’ showed a progressive postural tremor called Campus syndrome (CPS). Extensive backcross experiments suggested a dominant mode of inheritance, and the founder boar was believed to be a gonadal mosaic. A genome-scan mapped the disease-causing mutation to an 8 cM region of porcine chromosome 7 containing the MHY7 gene. Human distal myopathy type 1 (MPD1), a disease partially resembling CPS in pigs, has been associated with mutations in the MYH7 gene. Results The porcine MYH7 gene structure was predicted based on porcine reference genome sequence, porcine mRNA, and in comparison to the human ortholog. The gene structure was highly conserved with the exception of the first exon. Mutation analysis of a contiguous genomic interval of more than 22 kb spanning the complete MYH7 gene revealed an in-frame insertion within exon 30 of MYH7 (c.4320_4321insCCCGCC) which was perfectly associated with the disease phenotype and confirmed the dominant inheritance. The mutation is predicted to insert two amino acids (p.Ala1440_Ala1441insProAla) in a very highly conserved region of the myosin tail. The boar ‘Campus’ was shown to be a germline and somatic mosaic as assessed by the presence of the mutant allele in seven different organs. Conclusion This study illustrates the usefulness of recently established genomic resources in pigs. We have identified a spontaneous mutation in MYH7 as the causative mutation for CPS. This paper describes the first case of a disorder caused by a naturally occurring mutation in the MYH7 gene of a non-human mammalian species. Our study confirms the previous classification as a primary myopathy and provides a defined large animal model for human MPD1. We provide evidence that the CPS mutation occurred during the early development of the boar ‘Campus’. Therefore, this study provides an example of germline mosaicism with an asymptomatic founder.
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Affiliation(s)
- Leonardo Murgiano
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, Bern, 3001, Switzerland
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26
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A novel Myosin essential light chain mutation causes hypertrophic cardiomyopathy with late onset and low expressivity. Biochem Res Int 2012; 2012:685108. [PMID: 22957257 PMCID: PMC3432877 DOI: 10.1155/2012/685108] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 02/07/2012] [Indexed: 02/02/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is caused by mutations in genes encoding sarcomere proteins. Mutations in MYL3, encoding the essential light chain of myosin, are rare and have been associated with sudden death. Both recessive and dominant patterns of inheritance have been suggested. We studied a large family with a 38-year-old asymptomatic HCM-affected male referred because of a murmur. The patient had HCM with left ventricular hypertrophy (max WT 21 mm), a resting left ventricular outflow gradient of 36 mm Hg, and left atrial dilation (54 mm). Genotyping revealed heterozygosity for a novel missense mutation, p.V79I, in MYL3. The mutation was not found in 300 controls, and the patient had no mutations in 10 sarcomere genes. Cascade screening revealed a further nine heterozygote mutation carriers, three of whom had ECG and/or echocardiographic abnormalities but did not fulfil diagnostic criteria for HCM. The penetrance, if we consider this borderline HCM the phenotype of the p.V79I mutation, was 40%, but the mean age of the nonpenetrant mutation carriers is 15, while the mean age of the penetrant mutation carriers is 47. The mutation affects a conserved valine replacing it with a larger isoleucine residue in the region of contact between the light chain and the myosin lever arm. In conclusion, MYL3 mutations can present with low expressivity and late onset.
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Capek P, Vondrasek J, Skvor J, Brdicka R. Hypertrophic cardiomyopathy: from mutation to functional analysis of defective protein. Croat Med J 2012; 52:384-91. [PMID: 21674835 PMCID: PMC3118724 DOI: 10.3325/cmj.2011.52.384] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Aim To analyze the genesis of hypertrophic cardiomyopathy on a large cohort of patients from molecular genetics point of view and perform the functional analysis of the 3D molecular model of defective myosin-7 protein in silico. Methods The study enrolled 153 patients with diagnosed hypertrophic cardiomyopathy from different parts of the Czech Republic. DNA samples were analyzed for mutations in exons 21 and 22 of the MYH7 gene, which have been associated with high mutation clustering. The 3D model of human myosin-7 was built using the x-ray structure of nucleotide-free scallop myosin S1 as the structural template. We performed de novo structure prediction of mutant and wild type peptides spanning the 769-788 amino acids region of the myosin-7 protein. Results The Arg870His and Asp778Val amino acid alterations were found in 2 unrelated patients with a severe form of hypertrophic cardiomyopathy. The Asp778Val variation was chosen for subsequent 3D molecular modeling in silico. The mutation of the Asp by Val not only changes the character of the interaction pattern with other amino acids or ions but Val, being a small hydrophobic amino acid, can also completely change the stability of the region. Conclusion Mutation location in the MYH7 gene and changes in amino acid composition may have a crucial negative impact on the outcome of the disease in patients with hypertrophic cardiomyopathy. In addition, a mutation that changes the charge of the amino acid is more likely to affect protein function than a conservative mutation.
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Affiliation(s)
- Pavel Capek
- Department of Anthropology and Human Genetics, Charles University, Prague, Czech Republic.
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28
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Tripathi S, Schultz I, Becker E, Montag J, Borchert B, Francino A, Navarro-Lopez F, Perrot A, Özcelik C, Osterziel KJ, McKenna WJ, Brenner B, Kraft T. Unequal allelic expression of wild-type and mutated β-myosin in familial hypertrophic cardiomyopathy. Basic Res Cardiol 2011; 106:1041-55. [PMID: 21769673 PMCID: PMC3228959 DOI: 10.1007/s00395-011-0205-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 06/29/2011] [Accepted: 07/07/2011] [Indexed: 11/29/2022]
Abstract
Familial hypertrophic cardiomyopathy (FHC) is an autosomal dominant disease, which in about 30% of the patients is caused by missense mutations in one allele of the β-myosin heavy chain (β-MHC) gene (MYH7). To address potential molecular mechanisms underlying the family-specific prognosis, we determined the relative expression of mutant versus wild-type MYH7-mRNA. We found a hitherto unknown mutation-dependent unequal expression of mutant to wild-type MYH7-mRNA, which is paralleled by similar unequal expression of β-MHC at the protein level. Relative abundance of mutated versus wild-type MYH7-mRNA was determined by a specific restriction digest approach and by real-time PCR (RT-qPCR). Fourteen samples from M. soleus and myocardium of 12 genotyped and clinically well-characterized FHC patients were analyzed. The fraction of mutated MYH7-mRNA in five patients with mutation R723G averaged to 66 and 68% of total MYH7-mRNA in soleus and myocardium, respectively. For mutations I736T, R719W and V606M, fractions of mutated MYH7-mRNA in M. soleus were 39, 57 and 29%, respectively. For all mutations, unequal abundance was similar at the protein level. Importantly, fractions of mutated transcripts were comparable among siblings, in younger relatives and unrelated carriers of the same mutation. Hence, the extent of unequal expression of mutated versus wild-type transcript and protein is characteristic for each mutation, implying cis-acting regulatory mechanisms. Bioinformatics suggest mRNA stability or splicing effectors to be affected by certain mutations. Intriguingly, we observed a correlation between disease expression and fraction of mutated mRNA and protein. This strongly suggests that mutation-specific allelic imbalance represents a new pathogenic factor for FHC.
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Affiliation(s)
- Snigdha Tripathi
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
| | - Imke Schultz
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
- Present Address: Niederwiesenring 4, 63110 Rodgau, Germany
| | - Edgar Becker
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
| | - Judith Montag
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
| | - Bianca Borchert
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
- Present Address: Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Carl-Neuberg Str. 1, 30625 Hannover, Germany
| | - Antonio Francino
- Hospital Clinic/IDIBAPS, University of Barcelona, 08036 Barcelona, Spain
| | | | - Andreas Perrot
- Charité-Unversitätsmedizin Berlin, Experimental and Clinical Research Center (ECRC) am Max-Delbrück-Centrum für Molekulare Medizin, Kardio-Genetisches Labor, 13125 Berlin, Germany
| | - Cemil Özcelik
- Charité-Unversitätsmedizin Berlin, Experimental and Clinical Research Center (ECRC) am Max-Delbrück-Centrum für Molekulare Medizin, Kardio-Genetisches Labor, 13125 Berlin, Germany
- Charité-Universitätsmedizin Berlin, Kardiologie am Campus Virchow-Klinikum, 13353 Berlin, Germany
| | - Karl-Josef Osterziel
- Charité-Universitätsmedizin Berlin, Kardiologie am Campus Virchow-Klinikum, 13353 Berlin, Germany
- Present Address: Kardiologische Gemeinschaftspraxis, Marienstraße 9, 92224 Amberg, Germany
| | - William J. McKenna
- Institute of Cardiovascular Science, University College London, London, WC1E 6BT United Kingdom
| | - Bernhard Brenner
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover, Germany
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Structural basis for myopathic defects engendered by alterations in the myosin rod. J Mol Biol 2011; 414:477-84. [PMID: 22037585 DOI: 10.1016/j.jmb.2011.10.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Revised: 10/03/2011] [Accepted: 10/12/2011] [Indexed: 12/12/2022]
Abstract
While mutations in the myosin subfragment 1 motor domain can directly disrupt the generation and transmission of force along myofibrils and lead to myopathy, the mechanism whereby mutations in the myosin rod influences mechanical function is less clear. Here, we used a combination of various imaging techniques and molecular dynamics simulations to test the hypothesis that perturbations in the myosin rod can disturb normal sarcomeric uniformity and, like motor domain lesions, would influence force production and propagation. We show that disrupting the rod can alter its nanomechanical properties and, in vivo, can drive asymmetric myofilament and sarcomere formation. Our imaging results indicate that myosin rod mutations likely disturb production and/or propagation of contractile force. This provides a unifying theory where common pathological cascades accompany both myosin motor and specific rod domain mutations. Finally, we suggest that sarcomeric inhomogeneity, caused by asymmetric thick filaments, could be a useful index of myopathic dysfunction.
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Haas J, Katus HA, Meder B. Next-generation sequencing entering the clinical arena. Mol Cell Probes 2011; 25:206-11. [PMID: 21914469 DOI: 10.1016/j.mcp.2011.08.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 08/29/2011] [Accepted: 08/29/2011] [Indexed: 10/17/2022]
Abstract
Over the last decade the genetic etiology of many heritable diseases could be resolved. For heart muscle diseases, so called cardiomyopathies, mutations in more than 40 different genes have been identified. Due to this large genetic heterogeneity and missing of adequate gene-diagnostic tools, most patients are not genetically characterized, which would be important for individualized patient care. Currently, next-generation sequencing technologies are revolutionizing genetic and epigenetic research, since they are capable to produce billions of bases of sequence information in a single experiment. Accordingly, this powerful technology can now also open avenues for genetic diagnostics. The scope of this article is to illustrate technical approaches, clinical applications, and yet unsolved problems of next-generation sequencing entering the clinical arena.
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Affiliation(s)
- Jan Haas
- Department of Internal Medicine III, University of Heidelberg, Im Neuenheimer Feld 350, Heidelberg 69120, Germany
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Exome sequencing identified MYO1E and NEIL1 as candidate genes for human autosomal recessive steroid-resistant nephrotic syndrome. Kidney Int 2011; 80:389-96. [PMID: 21697813 DOI: 10.1038/ki.2011.148] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To identify gene loci associated with steroid-resistant nephrotic syndrome (SRNS), we utilized homozygosity mapping and exome sequencing in a consanguineous pedigree with three affected siblings. High-density genotyping identified three segments of homozygosity spanning 33.6 Mb on chromosomes 5, 10, and 15 containing 296 candidate genes. Exome sequencing identified two homozygous missense variants within the chromosome 15 segment; an A159P substitution in myosin 1E (MYO1E), encoding a podocyte cytoskeletal protein; and an E181K substitution in nei endonuclease VIII-like 1 (NEIL1), encoding a base-excision DNA repair enzyme. Both variants disrupt highly conserved protein sequences and were absent in public databases, 247 healthy controls, and 286 patients with nephrotic syndrome. The MYO1E A159P variant is noteworthy, as it is expected to impair ligand binding and actin interaction in the MYO1E motor domain. The predicted loss of function is consistent with the previous demonstration that Myo1e inactivation produces nephrotic syndrome in mice. Screening 71 additional patients with SRNS, however, did not identify independent NEIL1 or MYO1E mutations, suggesting larger sequencing efforts are needed to uncover which mutation is responsible for the phenotype. Our findings demonstrate the utility of exome sequencing for rapidly identifying candidate genes for human SRNS.
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Meder B, Haas J, Keller A, Heid C, Just S, Borries A, Boisguerin V, Scharfenberger-Schmeer M, Stähler P, Beier M, Weichenhan D, Strom TM, Pfeufer A, Korn B, Katus HA, Rottbauer W. Targeted next-generation sequencing for the molecular genetic diagnostics of cardiomyopathies. ACTA ACUST UNITED AC 2011; 4:110-22. [PMID: 21252143 DOI: 10.1161/circgenetics.110.958322] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Today, mutations in more than 30 different genes have been found to cause inherited cardiomyopathies, some associated with very poor prognosis. However, because of the genetic heterogeneity and limitations in throughput and scalability of current diagnostic tools up until now, it is hardly possible to genetically characterize patients with cardiomyopathy in a fast, comprehensive, and cost-efficient manner. METHODS AND RESULTS We established an array-based subgenomic enrichment followed by next-generation sequencing to detect mutations in patients with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). With this approach, we show that the genomic region of interest can be enriched by a mean factor of 2169 compared with the coverage of the whole genome, resulting in high sequence coverage of selected disease genes and allowing us to define the genetic pathogenesis of cardiomyopathies in a single sequencing run. In 6 patients, we detected disease-causing mutations, 2 microdeletions, and 4 point mutations. Furthermore, we identified several novel nonsynonymous variants, which are predicted to be harmful, and hence, might be potential disease mutations or modifiers for DCM or HCM. CONCLUSIONS The approach presented here allows for the first time a comprehensive genetic screening in patients with hereditary DCM or HCM in a fast and cost-efficient manner.
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Affiliation(s)
- Benjamin Meder
- Department of Internal Medicine III, University of Heidelberg, Heidelberg, Germany
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Homayoun H, Khavandgar S, Hoover JM, Mohsen AW, Vockley J, Lacomis D, Clemens PR. Novel mutation in MYH7 gene associated with distal myopathy and cardiomyopathy. Neuromuscul Disord 2011; 21:219-22. [PMID: 21211974 DOI: 10.1016/j.nmd.2010.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 11/28/2010] [Accepted: 12/07/2010] [Indexed: 01/17/2023]
Abstract
A 25-year-old woman had childhood-onset muscle weakness and dilated cardiomyopathy. She exhibited predominantly distal weakness with early toe walking. Dilated cardiomyopathy required cardiac transplantation at age 15 years. We identified a de-novo, heterozygous, missense mutation, c.2348G>C (p. Arg783Pro), in exon 21 of the MYH7 gene, which encodes slow skeletal muscle fiber/β-cardiac myosin heavy chain protein, that replaces a highly conserved arginine with a proline. This novel mutation that results in the unusual combined cardiac and skeletal muscle phenotype localizes to the essential light chain binding area, a region only previously shown to be mutated in hypertrophic cardiomyopathy.
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Affiliation(s)
- Houman Homayoun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
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Granados-Riveron JT, Ghosh TK, Pope M, Bu'Lock F, Thornborough C, Eason J, Kirk EP, Fatkin D, Feneley MP, Harvey RP, Armour JAL, David Brook J. Alpha-cardiac myosin heavy chain (MYH6) mutations affecting myofibril formation are associated with congenital heart defects. Hum Mol Genet 2010; 19:4007-16. [PMID: 20656787 DOI: 10.1093/hmg/ddq315] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Congenital heart defects (CHD) are collectively the most common form of congenital malformation. Studies of human cases and animal models have revealed that mutations in several genes are responsible for both familial and sporadic forms of CHD. We have previously shown that a mutation in MYH6 can cause an autosomal dominant form of atrial septal defect (ASD), whereas others have identified mutations of the same gene in patients with hypertrophic and dilated cardiomyopathy. In the present study, we report a mutation analysis of MYH6 in patients with a wide spectrum of sporadic CHD. The mutation analysis of MYH6 was performed in DNA samples from 470 cases of isolated CHD using denaturing high-performance liquid chromatography and sequence analysis to detect point mutations and small deletions or insertions, and multiplex amplifiable probe hybridization to detect partial or complete copy number variations. One non-sense mutation, one splicing site mutation and seven non-synonymous coding mutations were identified. Transfection of plasmids encoding mutant and non-mutant green fluorescent protein-MYH6 fusion proteins in mouse myoblasts revealed that the mutations A230P and A1366D significantly disrupt myofibril formation, whereas the H252Q mutation significantly enhances myofibril assembly in comparison with the non-mutant protein. Our data indicate that functional variants of MYH6 are associated with cardiac malformations in addition to ASD and provide a novel potential mechanism. Such phenotypic heterogeneity has been observed in other genes mutated in CHD.
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Affiliation(s)
- Javier T Granados-Riveron
- Institute of Genetics, School of Biology, Queen’s Medical Centre, University of Nottingham, Nottingham, UK
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Targeting of the hair cell proteins cadherin 23, harmonin, myosin XVa, espin, and prestin in an epithelial cell model. J Neurosci 2010; 30:7187-201. [PMID: 20505086 DOI: 10.1523/jneurosci.0852-10.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We have developed an advantageous epithelial cell transfection model for examining the targeting, interactions, and mutations of hair cell proteins. When expressed in LLC-PK1-CL4 epithelial cells (CL4 cells), the outer hair cell protein prestin showed faithful domain-specific targeting to the basolateral plasma membrane. We examined the consequences of mutations affecting prestin activity and assigned a targeting role to the cytoplasmic tail. The stereociliary link protein cadherin 23 (Cdh23) was targeted to the plasma membrane of CL4 cell microvilli, the topological equivalent of stereocilia. In cells coexpressing the Cdh23 cytoplasmic binding protein harmonin, a large fraction of harmonin became colocalized with Cdh23 in microvilli. Using this assay and in vitro protein binding assays, we formulated an alternative model for Cdh23-harmonin binding, in which the primary interaction is between the harmonin N-domain and a 35-residue internal peptide in the Cdh23 cytoplasmic tail. Contrary to a previous model, we found no role for the Cdh23 C-terminal PDZ (PSD-95/Dlg/ZO-1)-binding motif and observed that Cdh23 bound similar levels of harmonin with or without the exon 68 peptide. We also examined two proteins involved in stereocilium elongation. The stereociliary actin-bundling protein espin was targeted to CL4 cell microvilli and caused microvillar elongation, whereas espin with the c.2469delGTCA or c.1988delAGAG human deafness mutation showed defects in microvillar targeting and elongation. The unconventional myosin motor myosin XVa accumulated at the tips of espin-elongated microvilli, by analogy to its location in stereocilia, whereas myosin XVa with the c.4351G>A or c.4669A>G human deafness mutation did not, revealing functional deficits in motor activity.
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Xu Q, Dewey S, Nguyen S, Gomes AV. Malignant and benign mutations in familial cardiomyopathies: Insights into mutations linked to complex cardiovascular phenotypes. J Mol Cell Cardiol 2010; 48:899-909. [DOI: 10.1016/j.yjmcc.2010.03.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 03/01/2010] [Accepted: 03/06/2010] [Indexed: 12/17/2022]
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Kimura A. Molecular basis of hereditary cardiomyopathy: abnormalities in calcium sensitivity, stretch response, stress response and beyond. J Hum Genet 2010; 55:81-90. [PMID: 20075948 DOI: 10.1038/jhg.2009.138] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cardiomyopathy is caused by functional abnormality of cardiac muscle. The functional abnormality involved in its etiology includes both extrinsic and intrinsic factors, and cardiomyopathy caused by the intrinsic factors is called as idiopathic or primary cardiomyopathy. There are several clinical types of primary cardiomyopathy including hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Linkage studies and candidate gene approaches have explored the disease genes for hereditary primary cardiomyopathy. The most notable finding was that mutations in the same disease gene can be found in different clinical types of cardiomyopathy. Functional analyses of disease-related mutations have revealed that characteristic functional alterations are associated with the clinical types, such that increased and decreased Ca(2+) sensitivity due to sarcomere mutations are associated with HCM and DCM, respectively. In addition, our recent studies have suggested that mutations in the Z-disc components found in HCM and DCM may result in increased and decreased stiffness of sarcomere; that is, stiff sarcomere and loose sarcomere, respectively, and hence altered stretch response. More recently, mutations in the components of I region were found in hereditary cardiomyopathy and the functional analyses of the mutations suggested that the altered stress response was associated with cardiomyopathy, further complicating the etiology and pathogenesis. However, elucidation of genetic etiology and functional alterations caused by the mutations shed lights on the new therapeutic approaches to hereditary cardiomyopathy, such that treatment of DCM with a Ca(2+) sensitizer prevented the disease in a mouse model.
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Affiliation(s)
- Akinori Kimura
- Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Japan.
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38
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Purushotham G, Madhumohan K, Anwaruddin M, Nagarajaram HA, Hariram V, Narasimhan C, Bashyam MD. The MYH7 p.R787H mutation causes hypertrophic cardiomyopathy in two unrelated families. Exp Clin Cardiol 2010; 15:e1-e4. [PMID: 20664766 PMCID: PMC2907879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 02/12/2010] [Indexed: 05/29/2023]
Abstract
BACKGROUND Familial hypertrophic cardiomyopathy (FHC) is a Mendelian disorder usually caused by mutations in any one of more than 12 genes, most of which encode sarcomere proteins. The disease exhibits extensive genetic heterogeneity, and it is important to identify mutations that result in adverse symptoms and/or lethality in affected individuals. An analysis of disease-causing mutations has been initiated in the Indian population to determine prevalent mutations. METHODS FHC was detected using echocardiography and by analysis of clinical symptoms and family history. The disease-causing mutation was identified using polymerase chain reaction DNA sequencing. RESULTS The p.R787H mutation was identified in the MYH7 gene in two FHC families. Sequence and structure analysis suggested impaired binding of the mutant protein to the myosin essential light chain. CONCLUSIONS Although the mutation results in variable clinical symptoms in the affected individuals, probably owing to the effect of modifier genes and/or environmental factors, it does not appear to be a lethal mutation.
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Affiliation(s)
| | | | - Mohammad Anwaruddin
- Laboratory of Computational Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD)
| | - HA Nagarajaram
- Laboratory of Computational Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD)
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39
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Ventricular fibrillation in MYH7-related hypertrophic cardiomyopathy before onset of ventricular hypertrophy. Heart Rhythm 2009; 6:1366-9. [DOI: 10.1016/j.hrthm.2009.04.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 04/21/2009] [Indexed: 11/23/2022]
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40
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Ajtai K, Halstead MF, Nyitrai M, Penheiter AR, Zheng Y, Burghardt TP. The myosin C-loop is an allosteric actin contact sensor in actomyosin. Biochemistry 2009; 48:5263-75. [PMID: 19408946 PMCID: PMC2759872 DOI: 10.1021/bi900584q] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Actin and myosin form the molecular motor in muscle. Myosin is the enzyme performing ATP hydrolysis under the allosteric control of actin such that actin binding initiates product release and force generation in the myosin power stroke. Non-equilibrium Monte Carlo molecular dynamics simulation of the power stroke suggested that a structured surface loop on myosin, the C-loop, is the actin contact sensor initiating actin activation of the myosin ATPase. Previous experimental work demonstrated C-loop binds actin and established the forward and reverse allosteric link between the C-loop and the myosin active site. Here, smooth muscle heavy meromyosin C-loop chimeras were constructed with skeletal (sCl) and cardiac (cCl) myosin C-loops substituted for the native sequence. In both cases, actin-activated ATPase inhibition is indicated mainly by the lower V(max). In vitro motility was also inhibited in the chimeras. Motility data were collected as a function of myosin surface density, with unregulated actin, and with skeletal and cardiac isoforms of tropomyosin-bound actin for the wild type, cCl, and sCl. Slow and fast subpopulations of myosin velocities in the wild-type species were discovered and represent geometrically unfavorable and favorable actomyosin interactions, respectively. Unfavorable interactions are detected at all surface densities tested. Favorable interactions are more probable at higher myosin surface densities. Cardiac tropomyosin-bound actin promotes the favorable actomyosin interactions by lowering the inhibiting geometrical constraint barriers with a structural effect on actin. Neither higher surface density nor cardiac tropomyosin-bound actin can accelerate motility velocity in cCl or sCl, suggesting the element initiating maximal myosin activation by actin resides in the C-loop.
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Affiliation(s)
- Katalin Ajtai
- Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Miriam F. Halstead
- Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Miklós Nyitrai
- Department of Biophysics, University of Pécs, Pécs, Hungary
| | - Alan R. Penheiter
- Molecular Medicine Program, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Ye Zheng
- Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Thomas P. Burghardt
- Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
- Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
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41
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Davis J, Westfall MV, Townsend D, Blankinship M, Herron TJ, Guerrero-Serna G, Wang W, Devaney E, Metzger JM. Designing heart performance by gene transfer. Physiol Rev 2008; 88:1567-651. [PMID: 18923190 DOI: 10.1152/physrev.00039.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The birth of molecular cardiology can be traced to the development and implementation of high-fidelity genetic approaches for manipulating the heart. Recombinant viral vector-based technology offers a highly effective approach to genetically engineer cardiac muscle in vitro and in vivo. This review highlights discoveries made in cardiac muscle physiology through the use of targeted viral-mediated genetic modification. Here the history of cardiac gene transfer technology and the strengths and limitations of viral and nonviral vectors for gene delivery are reviewed. A comprehensive account is given of the application of gene transfer technology for studying key cardiac muscle targets including Ca(2+) handling, the sarcomere, the cytoskeleton, and signaling molecules and their posttranslational modifications. The primary objective of this review is to provide a thorough analysis of gene transfer studies for understanding cardiac physiology in health and disease. By comparing results obtained from gene transfer with those obtained from transgenesis and biophysical and biochemical methodologies, this review provides a global view of cardiac structure-function with an eye towards future areas of research. The data presented here serve as a basis for discovery of new therapeutic targets for remediation of acquired and inherited cardiac diseases.
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Affiliation(s)
- Jennifer Davis
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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42
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Herron TJ, Devaney EJ, Metzger JM. Modulation of cardiac performance by motor protein gene transfer. Ann N Y Acad Sci 2008; 1123:96-104. [PMID: 18375581 DOI: 10.1196/annals.1420.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cardiac muscle performance can be determined by factors intrinsic to each cardiac muscle cell, such as protein isoform expression. One protein whose expression plays a major role in determining cardiac performance is myosin. Myosin is the heart's molecular motor which transduces the chemical energy from ATP hydrolysis into the mechanical energy of each heartbeat. Alterations of myosin isoform expression are routinely associated with acquired and inherited cases of cardiomyopathy. For example, human heart failure is consistently associated with increased expression of a slow myosin motor isoform and a concomitant decreased expression of the heart's fast myosin motor isoform. Further, mutations of the cardiac myosin gene are the most common cause of inherited hypertrophic cardiomyopathy. Transgenic animal studies have provided insight into cardiac functional effects caused by myosin isoform gene switching (fast-to-slow myosin or slow-to-fast myosin) or by expression of a disease-related mutant motor. More direct structure-function analysis using acute gene transfer of myosin motors provides evidence that the inotropic state of cardiac muscle can be affected by motor protein isoform shifting independent of intracellular calcium handling. Because most therapies for the diseased heart target intracellular calcium handling, acute gene transfer of cardiac molecular motors to modulate heart performance offers a novel therapeutic strategy for the compromised heart. Although the development of safe vectors for therapeutic myosin gene delivery are in their infancy, studies focused on acute genetic engineering of the heart's molecular motor will provide a foundation for therapeutic vector development and insight into mechanisms that contribute to cardiomyopathy.
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Affiliation(s)
- Todd J Herron
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
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43
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Klaassen S, Probst S, Oechslin E, Gerull B, Krings G, Schuler P, Greutmann M, Hürlimann D, Yegitbasi M, Pons L, Gramlich M, Drenckhahn JD, Heuser A, Berger F, Jenni R, Thierfelder L. Mutations in sarcomere protein genes in left ventricular noncompaction. Circulation 2008; 117:2893-901. [PMID: 18506004 DOI: 10.1161/circulationaha.107.746164] [Citation(s) in RCA: 305] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Left ventricular noncompaction constitutes a primary cardiomyopathy characterized by a severely thickened, 2-layered myocardium, numerous prominent trabeculations, and deep intertrabecular recesses. The genetic basis of this cardiomyopathy is still largely unresolved. We speculated that mutations in sarcomere protein genes known to cause hypertrophic cardiomyopathy and dilated cardiomyopathy may be associated with left ventricular noncompaction. METHODS AND RESULTS Mutational analysis in a cohort of 63 unrelated adult probands with left ventricular noncompaction and no other congenital heart anomalies was performed by denaturing high-performance liquid chromatography analysis and direct DNA sequencing of 6 genes encoding sarcomere proteins. Heterozygous mutations were identified in 11 of 63 samples in genes encoding beta-myosin heavy chain (MYH7), alpha-cardiac actin (ACTC), and cardiac troponin T (TNNT2). Nine distinct mutations, 7 of them in MYH7, 1 in ACTC, and 1 in TNNT2, were found. Clinical evaluations demonstrated familial disease in 6 of 11 probands with sarcomere gene mutations. MYH7 mutations segregated with the disease in 4 autosomal dominant LVNC kindreds. Six of the MYH7 mutations were novel, and 1 encodes a splice-site mutation, a relatively unique finding for MYH7 mutations. Modified residues in beta-myosin heavy chain were located mainly within the ATP binding site. CONCLUSIONS We conclude that left ventricular noncompaction is within the diverse spectrum of cardiac morphologies triggered by sarcomere protein gene defects. Our findings support the hypothesis that there is a shared molecular etiology of different cardiomyopathic phenotypes.
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Affiliation(s)
- Sabine Klaassen
- Max Delbrück Center for Molecular Medicine, Robert Roessle Strasse 10, 13092 Berlin, Germany.
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Noncompaction of the ventricular myocardium is associated with a de novo mutation in the beta-myosin heavy chain gene. PLoS One 2007; 2:e1362. [PMID: 18159245 PMCID: PMC2137931 DOI: 10.1371/journal.pone.0001362] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 12/03/2007] [Indexed: 11/19/2022] Open
Abstract
Noncompaction of the ventricular myocardium (NVM) is the morphological hallmark of a rare familial or sporadic unclassified heart disease of heterogeneous origin. NVM results presumably from a congenital developmental error and has been traced back to single point mutations in various genes. The objective of this study was to determine the underlying genetic defect in a large German family suffering from NVM. Twenty four family members were clinically assessed using advanced imaging techniques. For molecular characterization, a genome-wide linkage analysis was undertaken and the disease locus was mapped to chromosome 14ptel-14q12. Subsequently, two genes of the disease interval, MYH6 and MYH7 (encoding the α- and β-myosin heavy chain, respectively) were sequenced, leading to the identification of a previously unknown de novo missense mutation, c.842G>C, in the gene MYH7. The mutation affects a highly conserved amino acid in the myosin subfragment-1 (R281T). In silico simulations suggest that the mutation R281T prevents the formation of a salt bridge between residues R281 and D325, thereby destabilizing the myosin head. The mutation was exclusively present in morphologically affected family members. A few members of the family displayed NVM in combination with other heart defects, such as dislocation of the tricuspid valve (Ebstein's anomaly, EA) and atrial septal defect (ASD). A high degree of clinical variability was observed, ranging from the absence of symptoms in childhood to cardiac death in the third decade of life. The data presented in this report provide first evidence that a mutation in a sarcomeric protein can cause noncompaction of the ventricular myocardium.
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Ware SM, Quinn ME, Ballard ET, Miller E, Uzark K, Spicer RL. Pediatric restrictive cardiomyopathy associated with a mutation in beta-myosin heavy chain. Clin Genet 2007; 73:165-70. [PMID: 18076673 DOI: 10.1111/j.1399-0004.2007.00939.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Most children do not have a known cause of cardiomyopathy which limits the potential for disease-specific therapies. Of the different phenotypic presentations of cardiomyopathy, the restrictive form carries the poorest prognosis and has the lowest rate of identification of etiology. We present the first description of a beta-myosin heavy chain gene mutation in an infant with restrictive cardiomyopathy requiring cardiac transplantation. As demonstrated by three-dimensional protein structure modeling, the missense mutation is in a highly conserved amino acid at the critical binding region for the essential light chain. This case emphasizes that mutations in sarcomeric proteins, which are known to cause hypertrophic cardiomyopathy in adults, may be associated with the development of restrictive physiology in childhood. Identification of the genetic basis of pediatric cardiomyopathy has important implications for management and genetic counseling.
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Affiliation(s)
- S M Ware
- Department of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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46
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Burghardt TP, Hu JY, Ajtai K. Myosin dynamics on the millisecond time scale. Biophys Chem 2007; 131:15-28. [PMID: 17913331 PMCID: PMC2505346 DOI: 10.1016/j.bpc.2007.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 08/27/2007] [Accepted: 08/27/2007] [Indexed: 11/20/2022]
Abstract
Myosin is a motor protein associating with actin and ATP. It translates along actin filaments against a force by transduction of free energy liberated with ATP hydrolysis. Various myosin crystal structures define time points during ATPase showing the protein undergoes large conformation change during transduction over a cycle with approximately 10 ms periodicity. The protein conformation trajectory between two intermediates in the cycle is surmised by non-equilibrium Monte Carlo simulation utilizing free-energy minimization. The trajectory shows myosin transduction of free energy to mechanical work giving evidence for: (i) a causal relationship between product release and work production in the native isoform that is correctly disrupted in a chemically modified protein, (ii) the molecular basis of ATP-sensitive tryptophan fluorescence enhancement and acrylamide quenching, (iii) an actin-binding site peptide containing the free-energy barrier to ATPase product release defining the rate limiting step and, (iv) a scenario for actin-activation of myosin ATPase.
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Affiliation(s)
- Thomas P Burghardt
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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47
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Investigation of the MYH11 gene in sporadic patients with an isolated persistently patent arterial duct. Cardiol Young 2007; 17:666-72. [PMID: 17956658 DOI: 10.1017/s1047951107001473] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Persistent patency of the arterial duct is one of the most common congenital cardiac malformations. We recently showed that mutations in the MYH11 gene result in a disease combining familial thoracic aortic aneurysm and dissection, along with patency of the arterial duct. It is also known that the smooth muscle myosin heavy chain is involved in the physiological closure of the arterial duct. With this in mind, we investigated whether the MYH11 gene was a susceptibility gene for sporadic occurrence of isolated persistent patency of the arterial duct. We sequenced the entire coding sequence of the MYH11 gene in 60 Caucasian children with persistent patency born after 36 weeks of gestation. The frequencies of rare genetic variants, and single nucleotide polymorphisms, were compared with 192 normal controls. Two possible functional missense mutations were found in two affected individuals. Another rare variant, specifically p.Arg1535Gln, and two coding polymorphisms, namely p.Ala1234Thr and p.Val1289Ala, had allele frequencies similar to those in controls. Haplotype analysis after estimating linkage disequilibrium was carried out using six polymorphisms. Individual genotypes were distributed similarly among cases and controls. Only one of the seven major haplotypes was significantly less frequent among cases, at 0.07, than among controls, when the figure was 0.22 (OR 0.23 [0.08-0.27]). Our findings suggest that the MYH11 gene is involved in only rare instances when persistent patency of the arterial duct occurs in sporadic fashion.
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Anan R, Niimura H, Takenaka T, Hamasaki S, Tei C. Mutations in the genes for sarcomeric proteins in Japanese patients with onset sporadic hypertrophic cardiomyopathy after age 40 years. Am J Cardiol 2007; 99:1750-4. [PMID: 17560888 DOI: 10.1016/j.amjcard.2007.01.066] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Revised: 01/12/2007] [Accepted: 01/12/2007] [Indexed: 10/23/2022]
Abstract
This study was conducted to assess the hypothesis that mutations in the genes for sarcomeric proteins are the molecular cause for older-onset sporadic hypertrophic cardiomyopathy (HC) in Japanese patients. Molecular genetic approaches have demonstrated that familial HC is caused by mutations in genes encoding sarcomeric proteins. Recent studies have shown that sarcomeric gene mutations can also be a molecular cause of older-onset and/or sporadic HC. However, genetic studies to date have examined only a limited number of older Caucasian patients with HC. Clinical evaluations were performed in patients with HC onset after 40 years of age, and the sequence encoding the beta-cardiac myosin heavy chain, cardiac troponin T, cardiac troponin I, cardiac myosin binding protein-C, myosin ventricular regulatory light chain, and myosin ventricular essential light chain genes was analyzed. When a putative mutation was identified, clinical evaluations and genetic studies were subsequently performed on all first-degree relatives. Forty-one patients with sporadic HC onset after 40 years of age (31 men, 10 women; mean age 63+/-10 years at the time of study) were studied. Four novel missense mutations in the cardiac myosin binding protein-C gene (arginine to tryptophan at codon 160, glutamic acid to lysine at codon 334, glycine to arginine at codon 507, and threonine to methionine at codon 1,046) and a previously reported missense mutation in the beta-cardiac myosin heavy chain gene (arginine to histidine at codon 663) were identified in 5 of the 41 patients. No family members carried these mutations or had clinical evidence of HC. In conclusion, mutations in the cardiac myosin binding protein-C are the most common cause of older-onset sporadic HC in Japan.
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Affiliation(s)
- Ryuichiro Anan
- Department of Cardiovascular, Respiratory and Metabolic Medicine, Kagoshima University, Kagoshima, Japan.
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Eddinger TJ, Meer DP. Myosin II isoforms in smooth muscle: heterogeneity and function. Am J Physiol Cell Physiol 2007; 293:C493-508. [PMID: 17475667 DOI: 10.1152/ajpcell.00131.2007] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Both smooth muscle (SM) and nonmuscle class II myosin molecules are expressed in SM tissues comprising hollow organ systems. Individual SM cells may express one or more of multiple myosin II isoforms that differ in myosin heavy chain (MHC) and myosin light chain (MLC) subunits. Although much has been learned, the expression profiles, organization within contractile filaments, localization within cells, and precise roles in various contractile functions of these different myosin molecules are still not well understood. However, data supporting unique physiological roles for certain isoforms continues to build. Isoform differences located in the S1 head region of the MHC can alter actin binding and rates of ATP hydrolysis. Differences located in the MHC tail can alter the formation, stability, and size of the myosin thick filament. In these distinct ways, both head and tail isoform differences can alter force generation and muscle shortening velocities. The MLCs that are associated with the lever arm of the S1 head can affect the flexibility and range of motion of this domain and possibly the motion of the S2 and motor domains. Phosphorylation of MLC(20) has been associated with conformational changes in the S1 and/or S2 fragments regulating enzymatic activity of the entire myosin molecule. A challenge for the future will be delineation of the physiological significance of the heterogeneous expression of these isoforms in developmental, tissue-specific, and species-specific patterns and or the intra- and intercellular heterogeneity of myosin isoform expression in SM cells of a given organ.
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Affiliation(s)
- Thomas J Eddinger
- Biological Sciences, Marquette University, Milwaukee, WI 53233, USA.
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Oldfors A. Hereditary myosin myopathies. Neuromuscul Disord 2007; 17:355-67. [PMID: 17434305 DOI: 10.1016/j.nmd.2007.02.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 02/03/2007] [Accepted: 02/03/2007] [Indexed: 12/11/2022]
Abstract
Hereditary myosin myopathies have emerged as a new group of muscle diseases with highly variable clinical features and onset during fetal development, childhood or adulthood. They are caused by mutations in skeletal muscle myosin heavy chain (MyHC) genes. Mutations have been reported in two of the three MyHC isoforms expressed in adult limb skeletal muscle: type I (slow/beta-cardiac MyHC; MYH7) and type IIa (MYH2). The majority of more than 200 dominant missense mutations in MYH7 are associated with hypertrophic/dilated cardiomyopathy without signs or symptoms of skeletal myopathy. Several mutations in two different parts of the slow/beta-cardiac MyHC rod region are associated with two distinct skeletal myopathies without cardiomyopathy: Laing early onset distal myopathy and myosin storage myopathy (MSM). However, early onset distal myopathy and MSM caused by MYH7 mutations may also occur together with cardiomyopathy. MSM affects proximal or scapuloperoneal muscles whereas Laing distal myopathy primarily affects the dorsiflexor muscles of the toes and ankles. MSM is morphologically characterized by subsarcolemmal accumulation of myosin in type 1 fibers, whereas Laing distal myopathy is associated with variable and unspecific muscle pathology, frequently with hypotrophic type 1 muscle fibers. A myopathy associated with a specific mutation in MYH2 is associated with congenital joint contractures and external ophthalmoplegia. The disease is mild in childhood but may be progressive in adulthood, with proximal muscle weakness affecting ambulation. Mutations in embryonic MyHC (MYH3) and perinatal MyHC (MYH8), which are myosin isoforms expressed during muscle development, are associated with distal arthrogryposis syndromes with no or minor muscle weakness. Clinical findings, muscle morphology and molecular genetics in hereditary myosin myopathies are summarized in this review.
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Affiliation(s)
- Anders Oldfors
- Department of Pathology, Sahlgrenska University Hospital, S-413 45 Göteborg, Sweden.
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