1
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Functional Characterization of the MYO6 Variant p.E60Q in Non-Syndromic Hearing Loss Patients. Int J Mol Sci 2022; 23:ijms23063369. [PMID: 35328790 PMCID: PMC8949016 DOI: 10.3390/ijms23063369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/04/2022] [Accepted: 03/10/2022] [Indexed: 11/24/2022] Open
Abstract
Hereditary hearing loss (HHL) is a common genetic disorder accounting for at least 60% of pre-lingual deafness in children, of which 70% is inherited in an autosomal recessive pattern. The long tradition of consanguinity among the Qatari population has increased the prevalence of HHL, which negatively impacts the quality of life. Here, we functionally validated the pathogenicity of the c.178G>C, p.E60Q mutation in the MYO6 gene, which was detected previously in a Qatari HHL family, using cellular and animal models. In vitro analysis was conducted in HeLa cells transiently transfected with plasmids carrying MYO6WT or MYO6p.E60Q, and a zebrafish model was generated to characterize the in vivo phenotype. Cells transfected with MYO6WT showed higher expression of MYO6 in the plasma membrane and increased ATPase activity. Modeling the human MYO6 variants in zebrafish resulted in severe otic defects. At 72 h post-injection, MYO6p.E60Q embryos demonstrated alterations in the sizes of the saccule and utricle. Additionally, zebrafish with MYO6p.E60Q displayed super-coiled and bent hair bundles in otic hair cells when compared to control and MYO6WT embryos. In conclusion, our cellular and animal models add support to the in silico prediction that the p.E60Q missense variant is pathogenic and damaging to the protein. Since the c.178G>C MYO6 variant has a 0.5% allele frequency in the Qatari population, about 400 times higher than in other populations, it could contribute to explaining the high prevalence of hearing impairment in Qatar.
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2
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Suay-Corredera C, Alegre-Cebollada J. The mechanics of the heart: zooming in on hypertrophic cardiomyopathy and cMyBP-C. FEBS Lett 2022; 596:703-746. [PMID: 35224729 DOI: 10.1002/1873-3468.14301] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 11/10/2022]
Abstract
Hypertrophic cardiomyopathy (HCM), a disease characterized by cardiac muscle hypertrophy and hypercontractility, is the most frequently inherited disorder of the heart. HCM is mainly caused by variants in genes encoding proteins of the sarcomere, the basic contractile unit of cardiomyocytes. The most frequently mutated among them is MYBPC3, which encodes cardiac myosin-binding protein C (cMyBP-C), a key regulator of sarcomere contraction. In this review, we summarize clinical and genetic aspects of HCM and provide updated information on the function of the healthy and HCM sarcomere, as well as on emerging therapeutic options targeting sarcomere mechanical activity. Building on what is known about cMyBP-C activity, we examine different pathogenicity drivers by which MYBPC3 variants can cause disease, focussing on protein haploinsufficiency as a common pathomechanism also in nontruncating variants. Finally, we discuss recent evidence correlating altered cMyBP-C mechanical properties with HCM development.
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3
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Clinical, Genetic and Functional Characterization of a Novel AVPR2 Missense Mutation in a Woman with X-Linked Recessive Nephrogenic Diabetes Insipidus. J Pers Med 2022; 12:jpm12010118. [PMID: 35055433 PMCID: PMC8779739 DOI: 10.3390/jpm12010118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/27/2021] [Accepted: 01/05/2022] [Indexed: 11/28/2022] Open
Abstract
Nephrogenic diabetes insipidus (NDI) is a rare disorder characterized by renal unresponsiveness to the hormone vasopressin, leading to excretion of large volumes of diluted urine. Mutations in the arginine vasopressin receptor-2 (AVPR2) gene cause congenital NDI and have an X-linked recessive inheritance. The disorder affects almost exclusively male family members, but female carriers occasionally present partial phenotypes due to skewed inactivation of the X-chromosome. Here, we report a rare case of a woman affected with X-linked recessive NDI, presenting an average urinary output of 12 L/day. Clinical and biochemical studies showed incomplete responses to water deprivation and vasopressin stimulation tests. Genetic analyses revealed a novel heterozygous missense mutation (c.493G > C, p.Ala165Pro) in the AVPR2 gene. Using a combination of in-silico protein modeling with human cellular models and molecular phenotyping, we provide functional evidence for phenotypic effects. The mutation destabilizes the helical structure of the AVPR2 transmembrane domains and disrupts its plasma membrane localization and downstream intracellular signaling pathways upon activation with its agonist vasopressin. These defects lead to deficient aquaporin 2 (AQP2) membrane translocation, explaining the inability to concentrate urine in this patient.
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4
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Da'as SI, Yalcin HC, Nasrallah GK, Mohamed IA, Nomikos M, Yacoub MH, Fakhro KA. Functional characterization of human myosin-binding protein C3 variants associated with hypertrophic cardiomyopathy reveals exon-specific cardiac phenotypes in zebrafish model. J Cell Physiol 2020; 235:7870-7888. [PMID: 31943169 DOI: 10.1002/jcp.29441] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 12/20/2019] [Indexed: 12/27/2022]
Abstract
Myosin-binding protein C 3 (MYBPC3) variants are the most common cause of hypertrophic cardiomyopathy (HCM). HCM is a complex cardiac disorder due to its significant genetic and clinical heterogeneity. MYBPC3 variants genotype-phenotype associations remain poorly understood. We investigated the impact of two novel human MYBPC3 splice-site variants: V1: c.654+2_654+4dupTGG targeting exon 5 using morpholino MOe5i5; and V2: c.772+1G>A targeting exon 6 using MOe6i6; located within C1 domain of cMyBP-C protein, known to be critical in regulating sarcomere structure and contractility. Zebrafish MOe5i5 and MOe6i6 morphants recapitulated typical characteristics of human HCM with cardiac phenotypes of varying severity, including reduced cardiomyocyte count, thickened ventricular myocardial wall, a drastic reduction in heart rate, stroke volume, and cardiac output. Analysis of all cardiac morphological and functional parameters demonstrated that V2 cardiac phenotype was more severe than V1. Coinjection with synthetic human MYBPC3 messenger RNA (mRNA) partially rescued disparate cardiac phenotypes in each zebrafish morphant. While human MYBPC3 mRNA partially restored the decreased heart rate in V1 morphants and displayed increased percentages of ejection fraction, fractional shortening, and area change, it failed to revert the V1 ventricular myocardial thickness. These results suggest a possible V1 impact on cardiac contractility. In contrast, attempts to rescue V2 morphants only restored the ventricular myocardial wall hypertrophy phenotype but had no significant effect on impaired heart rate, suggesting a potential V2 impact on the cardiac structure. Our study provides evidence of an association between MYBPC3 exon-specific cardiac phenotypes in the zebrafish model providing important insights into how these genetic variants contribute to HCM disease.
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Affiliation(s)
- Sahar I Da'as
- Department of Human Genetics, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.,Sidra Medicine, Doha, Qatar
| | | | - Gheyath K Nasrallah
- Biomedical Research Center, Qatar University, Doha, Qatar.,Department of Biomedical Science, College of Health Sciences, Qatar University, Doha, Qatar
| | - Iman A Mohamed
- Center of Excellence for Stem Cells and Regenerative Medicine, Zewail City of Science and Technology, Egypt
| | - Michail Nomikos
- College of Medicine, Member of QU Health, Qatar University, Doha, Qatar
| | - Magdi H Yacoub
- Faculty of Medicine, Imperial College, National Heart & Lung Institute, UK
| | - Khalid A Fakhro
- Department of Human Genetics, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.,Sidra Medicine, Doha, Qatar.,Department of Genetic Medicine, Weill Cornell Medical College, Doha, Qatar
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5
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Aboelkassem Y, Powers JD, McCabe KJ, McCulloch AD. Multiscale Models of Cardiac Muscle Biophysics and Tissue Remodeling in Hypertrophic Cardiomyopathies. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2019; 11:35-44. [PMID: 31886450 DOI: 10.1016/j.cobme.2019.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Myocardial hypertrophy is the result of sustained perturbations to the mechanical and/or neurohormonal homeostasis of cardiac cells and is driven by integrated, multiscale biophysical and biochemical processes that are currently not well defined. In this brief review, we highlight recent computational and experimental models of cardiac hypertrophy that span mechanisms from the molecular level to the tissue level. Specifically, we focus on: (i) molecular-level models of the structural dynamics of sarcomere proteins in hypertrophic hearts, (ii) cellular-level models of excitation-contraction coupling and mechanosensitive signaling in disease-state myocytes, and (iii) organ-level models of myocardial growth kinematics and predictors thereof. Finally, we discuss how spanning these scales and combining multiple experimental/computational models will provide new information about the processes governing hypertrophy and potential methods to prevent or reverse them.
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Affiliation(s)
- Yasser Aboelkassem
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Joseph D Powers
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Kimberly J McCabe
- Department of Computational Physiology, Simula Research Laboratory, Lysaker, Norway
| | - Andrew D McCulloch
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
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6
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Ismail HM, Krishnamoorthy N, Al-Dewik N, Zayed H, Mohamed NA, Di Giacomo V, Gupta S, Häberle J, Thöny B, Blom HJ, Kruger WD, Ben-Omran T, Nasrallah GK. In silico and in vivo models for Qatari-specific classical homocystinuria as basis for development of novel therapies. Hum Mutat 2019; 40:230-240. [PMID: 30408270 PMCID: PMC6586426 DOI: 10.1002/humu.23682] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 11/05/2018] [Accepted: 11/06/2018] [Indexed: 02/05/2023]
Abstract
Homocystinuria is a rare inborn error of methionine metabolism caused by cystathionine β-synthase (CBS) deficiency. The prevalence of homocystinuria in Qatar is 1:1,800 births, mainly due to a founder Qatari missense mutation, c.1006C>T; p.R336C (p.Arg336Cys). We characterized the structure-function relationship of the p.R336C-mutant protein and investigated the effect of different chemical chaperones to restore p.R336C-CBS activity using three models: in silico, ΔCBS yeast, and CRISPR/Cas9 p.R336C knock-in HEK293T and HepG2 cell lines. Protein modeling suggested that the p.R336C induces severe conformational and structural changes, perhaps influencing CBS activity. Wild-type CBS, but not the p.R336C mutant, was able to restore the yeast growth in ΔCBS-deficient yeast in a complementation assay. The p.R336C knock-in HEK293T and HepG2 cells decreased the level of CBS expression and reduced its structural stability; however, treatment of the p.R336C knock-in HEK293T cells with betaine, a chemical chaperone, restored the stability and tetrameric conformation of CBS, but not its activity. Collectively, these results indicate that the p.R336C mutation has a deleterious effect on CBS structure, stability, and activity, and using the chemical chaperones approach for treatment could be ineffective in restoring p.R336C CBS activity.
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Affiliation(s)
- Hesham M. Ismail
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
- Biomedical Research Center, Qatar University, Doha, Qatar
| | - Navaneethakrishnan Krishnamoorthy
- Systems Biology Department, Sidra Medical and Research Centre, Doha, Qatar
- Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, UK
| | - Nader Al-Dewik
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - Hatem Zayed
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
| | | | - Valeria Di Giacomo
- ZeClinics SL, PRBB (Barcelona Biomedical Research Park), 08003 Barcelona, Spain
| | - Sapna Gupta
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, USA
| | - Johannes Häberle
- University Children’s Hospital and Children’s Research Center, Division of Metabolism, Zurich, Switzerland
| | - Beat Thöny
- University Children’s Hospital and Children’s Research Center, Division of Metabolism, Zurich, Switzerland
| | - Henk J. Blom
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, University Medical Centre Freiburg, Freiburg, Germany
| | - Waren D. Kruger
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, USA
| | - Tawfeg Ben-Omran
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - Gheyath K. Nasrallah
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
- Biomedical Research Center, Qatar University, Doha, Qatar
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7
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Hypertrophic cardiomyopathy-linked variants of cardiac myosin-binding protein C3 display altered molecular properties and actin interaction. Biochem J 2018; 475:3933-3948. [PMID: 30446606 DOI: 10.1042/bcj20180685] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 12/31/2022]
Abstract
The most common inherited cardiac disorder, hypertrophic cardiomyopathy (HCM), is characterized by thickening of heart muscle, for which genetic mutations in cardiac myosin-binding protein C3 (c-MYBPC3) gene, is the leading cause. Notably, patients with HCM display a heterogeneous clinical presentation, onset and prognosis. Thus, delineating the molecular mechanisms that explain how disparate c-MYBPC3 variants lead to HCM is essential for correlating the impact of specific genotypes on clinical severity. Herein, five c-MYBPC3 missense variants clinically associated with HCM were investigated; namely V1 (R177H), V2 (A216T), V3 (E258K), V4 (E441K) and double mutation V5 (V3 + V4), all located within the C1 and C2 domains of MyBP-C, a region known to interact with sarcomeric protein, actin. Injection of the variant complementary RNAs in zebrafish embryos was observed to recapitulate phenotypic aspects of HCM in patients. Interestingly, V3- and V5-cRNA injection produced the most severe zebrafish cardiac phenotype, exhibiting increased diastolic/systolic myocardial thickness and significantly reduced heart rate compared with control zebrafish. Molecular analysis of recombinant C0-C2 protein fragments revealed that c-MYBPC3 variants alter the C0-C2 domain secondary structure, thermodynamic stability and importantly, result in a reduced binding affinity to cardiac actin. V5 (double mutant), displayed the greatest protein instability with concomitant loss of actin-binding function. Our study provides specific mechanistic insight into how c-MYBPC3 pathogenic variants alter both functional and structural characteristics of C0-C2 domains leading to impaired actin interaction and reduced contractility, which may provide a basis for elucidating the disease mechanism in HCM patients with c- MYBPC3 mutations.
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8
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Risi C, Belknap B, Forgacs-Lonart E, Harris SP, Schröder GF, White HD, Galkin VE. N-Terminal Domains of Cardiac Myosin Binding Protein C Cooperatively Activate the Thin Filament. Structure 2018; 26:1604-1611.e4. [PMID: 30270174 PMCID: PMC6281772 DOI: 10.1016/j.str.2018.08.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/25/2018] [Accepted: 08/09/2018] [Indexed: 10/28/2022]
Abstract
Muscle contraction relies on interaction between myosin-based thick filaments and actin-based thin filaments. Myosin binding protein C (MyBP-C) is a key regulator of actomyosin interactions. Recent studies established that the N'-terminal domains (NTDs) of MyBP-C can either activate or inhibit thin filaments, but the mechanism of their collective action is poorly understood. Cardiac MyBP-C (cMyBP-C) harbors an extra NTD, which is absent in skeletal isoforms of MyBP-C, and its role in regulation of cardiac contraction is unknown. Here we show that the first two domains of human cMyPB-C (i.e., C0 and C1) cooperate to activate the thin filament. We demonstrate that C1 interacts with tropomyosin via a positively charged loop and that this interaction, stabilized by the C0 domain, is required for thin filament activation by cMyBP-C. Our data reveal a mechanism by which cMyBP-C can modulate cardiac contraction and demonstrate a function of the C0 domain.
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Affiliation(s)
- Cristina Risi
- Department of Physiological Sciences, Eastern Virginia Medical School, 700 West Olney Road, Lewis Hall, Room 3126, Norfolk, VA 23507, USA
| | - Betty Belknap
- Department of Physiological Sciences, Eastern Virginia Medical School, 700 West Olney Road, Lewis Hall, Room 3126, Norfolk, VA 23507, USA
| | - Eva Forgacs-Lonart
- Department of Physiological Sciences, Eastern Virginia Medical School, 700 West Olney Road, Lewis Hall, Room 3126, Norfolk, VA 23507, USA
| | - Samantha P Harris
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Gunnar F Schröder
- Institute of Complex Systems ICS-6, Forschungszentrum Jülich, 52425 Jülich, Germany; Physics Department, Heinrich-Heine Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Howard D White
- Department of Physiological Sciences, Eastern Virginia Medical School, 700 West Olney Road, Lewis Hall, Room 3126, Norfolk, VA 23507, USA
| | - Vitold E Galkin
- Department of Physiological Sciences, Eastern Virginia Medical School, 700 West Olney Road, Lewis Hall, Room 3126, Norfolk, VA 23507, USA.
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9
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Morgan A, Vuckovic D, Krishnamoorthy N, Rubinato E, Ambrosetti U, Castorina P, Franzè A, Vozzi D, La Bianca M, Cappellani S, Di Stazio M, Gasparini P, Girotto G. Next-generation sequencing identified SPATC1L as a possible candidate gene for both early-onset and age-related hearing loss. Eur J Hum Genet 2018; 27:70-79. [PMID: 30177775 PMCID: PMC6303261 DOI: 10.1038/s41431-018-0229-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 06/20/2018] [Accepted: 07/17/2018] [Indexed: 11/09/2022] Open
Abstract
Hereditary hearing loss (HHL) and age-related hearing loss (ARHL) are two major sensory diseases affecting millions of people worldwide. Despite many efforts, additional HHL-genes and ARHL genetic risk factors still need to be identified. To fill this gap a large genomic screening based on next-generation sequencing technologies was performed. Whole exome sequencing in a 3-generation Italian HHL family and targeted re-sequencing in 464 ARHL patients were performed. We detected three variants in SPATC1L: a nonsense allele in an HHL family and a frameshift insertion and a missense variation in two unrelated ARHL patients. In silico molecular modelling of all variants suggested a significant impact on the structural stability of the protein itself, likely leading to deleterious effects and resulting in truncated isoforms. After demonstrating Spatc1l expression in mice inner ear, in vitro functional experiments were performed confirming the results of the molecular modelling studies. Finally, a candidate-gene population-based statistical study in cohorts from Caucasus and Central Asia revealed a statistically significant association of SPATC1L with normal hearing function at low and medium hearing frequencies. Overall, the amount of different genetic data presented here (variants with early-onset and late-onset hearing loss in addition to genetic association with normal hearing function), together with relevant functional evidence, likely suggest a role of SPATC1L in hearing function and loss.
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Affiliation(s)
- Anna Morgan
- Department of Medical Sciences, University of Trieste, Trieste, Italy.
| | - Dragana Vuckovic
- Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Navaneethakrishnan Krishnamoorthy
- Sidra Medical and Research Center, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, UK
| | - Elisa Rubinato
- Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Umberto Ambrosetti
- UO Audiology, Fondazione IRCCS Ca Granda, Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan, Italy.,Audiology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Pierangela Castorina
- UO Audiology, Fondazione IRCCS Ca Granda, Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan, Italy
| | - Annamaria Franzè
- Ceinge Biotecnologie Avanzate, Naples, Italy; Istituto di Audiologia, Dipartimento di Neuroscienze, Scienze Riproduttive e Odontostomatologiche, Università di Napoli "Federico II", Naples, Italy
| | - Diego Vozzi
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Martina La Bianca
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Stefania Cappellani
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | | | - Paolo Gasparini
- Department of Medical Sciences, University of Trieste, Trieste, Italy.,Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Giorgia Girotto
- Department of Medical Sciences, University of Trieste, Trieste, Italy.,Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
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10
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Alkowari MK, Vozzi D, Bhagat S, Krishnamoorthy N, Morgan A, Hayder Y, Logendra B, Najjar N, Gandin I, Gasparini P, Badii R, Girotto G, Abdulhadi K. Targeted sequencing identifies novel variants involved in autosomal recessive hereditary hearing loss in Qatari families. Mutat Res 2017; 800-802:29-36. [PMID: 28501645 DOI: 10.1016/j.mrfmmm.2017.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/11/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
Hereditary hearing loss is characterized by a very high genetic heterogeneity. In the Qatari population the role of GJB2, the worldwide HHL major player, seems to be quite limited compared to Caucasian populations. In this study we analysed 18 Qatari families affected by non-syndromic hearing loss using a targeted sequencing approach that allowed us to analyse 81 genes simultaneously. Thanks to this approach, 50% of these families (9 out of 18) resulted positive for the presence of likely causative alleles in 6 different genes: CDH23, MYO6, GJB6, OTOF, TMC1 and OTOA. In particular, 4 novel alleles were detected while the remaining ones were already described to be associated to HHL in other ethnic groups. Molecular modelling has been used to further investigate the role of novel alleles identified in CDH23 and TMC1 genes demonstrating their crucial role in Ca2+ binding and therefore possible functional role in proteins. Present study showed that an accurate molecular diagnosis based on next generation sequencing technologies might largely improve molecular diagnostics outcome leading to benefits for both genetic counseling and definition of recurrence risk.
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Affiliation(s)
- Moza K Alkowari
- Division of Experimental Genetics, Sidra Medical and Research Centre, Doha, Qatar
| | - Diego Vozzi
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | | | - Navaneethakrishnan Krishnamoorthy
- Division of Experimental Genetics, Sidra Medical and Research Centre, Doha, Qatar; Heart Science Centre, National Heart and Lung Institute, Imperial College London, United Kingdom
| | - Anna Morgan
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy; Medical Sciences, Chirurgical and Health Department, University of Trieste, Trieste, Italy
| | | | | | | | - Ilaria Gandin
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Paolo Gasparini
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy; Medical Sciences, Chirurgical and Health Department, University of Trieste, Trieste, Italy
| | - Ramin Badii
- Molecular Genetics Laboratory, HMC, Doha, Qatar
| | - Giorgia Girotto
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy; Medical Sciences, Chirurgical and Health Department, University of Trieste, Trieste, Italy.
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11
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Mohamed IA, Krishnamoorthy NT, Nasrallah GK, Da'as SI. The Role of Cardiac Myosin Binding Protein C3 in Hypertrophic Cardiomyopathy-Progress and Novel Therapeutic Opportunities. J Cell Physiol 2017; 232:1650-1659. [PMID: 27731493 DOI: 10.1002/jcp.25639] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 10/07/2016] [Indexed: 11/11/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a common autosomal dominant genetic cardiovascular disorder marked by genetic and phenotypic heterogeneity. Mutations in the gene encodes the cardiac myosin-binding protein C, cMYBPC3 is amongst the various sarcomeric genes that are associated with HCM. These mutations produce mutated mRNAs and truncated cMyBP-C proteins. In this review, we will discuss the implications and molecular mechanisms involved in MYBPC3 different mutations. Further, we will highlight the novel targets that can be developed into potential therapeutics for the treatment of HMC. J. Cell. Physiol. 232: 1650-1659, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Iman A Mohamed
- Department of Biomedical Science, Zewail City of Science and Technology, Giza, Egypt
| | - Navaneethakrishnan T Krishnamoorthy
- Division of Experimental Genetics, Sidra Medical and Research Center, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, UK
| | - Gheyath K Nasrallah
- Department of Biomedical Science, College of Health Science, Qatar University, Doha, Qatar.,Biomedical Research Center, Qatar University, Doha, Qatar
| | - Sahar I Da'as
- Division of Experimental Genetics, Sidra Medical and Research Center, Doha, Qatar.,Department of Biomedical and Biological Sciences, Hamad Bin Khalifa University, Doha, Qatar
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12
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Zaki OK, Krishnamoorthy N, El Abd HS, Harche SA, Mattar RA, Al Disi RS, Nofal MY, El Bekay R, Ahmed KA, George Priya Doss C, Zayed H. Two patients with Canavan disease and structural modeling of a novel mutation. Metab Brain Dis 2017; 32:171-177. [PMID: 27531131 DOI: 10.1007/s11011-016-9896-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
Canavan disease (CD) is a rare fatal childhood neurological autosomal recessive genetic disease caused by mutations in the ASPA gene, which lead to catalytic deficiency of the ASPA enzyme, which catalyzes the hydrolysis of N-acetyl-L-aspartate (NAA) into aspartate and acetate. CD occurs frequently among Ashkenazi Jewish population, however it has been reported in many other ethnic groups with significantly lower frequency. Here, we report on two Egyptian patients diagnosed with CD, the first patient harbors five missense mutations (c.427 A > G; p. I143V, c.502C > T; p. R168C, c.530 T > C; p. I177T, c.557 T > C; p. V186D c.548C > T; p. P183L) and a silent mutation (c.693 C > T; p. Y231Y). The second patient was found to be homozygous for two missense mutations (c.427 A > G; p. I143V and c.557 T > A; p. V186D). Furthermore, molecular modeling of the novel mutation p. P183L provides an instructive explanation of the mutational impact on the protein structure that can affect the function of the ASPA. Here, the clinical, radiological, and biochemical profile of the two patients are reviewed in details.
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Affiliation(s)
- Osama K Zaki
- Medical Genetics Unit, Pediatric Department, Faculty of Medicine, Ain Shams University Hospital, Cairo, 11665, Egypt.
| | - Navaneethakrishnan Krishnamoorthy
- Division of Experimental Genetics, Sidra Medical and Research Centre, Qatar Foundation, Doha, Qatar
- Heart Science Centre, National Heart and Lung Institute, Imperial College London, Harefield, UK
| | - Heba S El Abd
- Medical Genetics Unit, Pediatric Department, Faculty of Medicine, Ain Shams University Hospital, Cairo, 11665, Egypt
| | - Soumaya A Harche
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
| | - Reem A Mattar
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
| | - Rana S Al Disi
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
| | - Mariam Y Nofal
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
| | - Rajaa El Bekay
- Laboratory of Biomedical Research, Virgen de la Victoria Clinical University Hospital, 29010, Málaga, Spain
| | - Khalid A Ahmed
- Medical Genetics Unit, Pediatric Department, Faculty of Medicine, Ain Shams University Hospital, Cairo, 11665, Egypt
| | - C George Priya Doss
- Department of Integrative Biology, School of Biosciences and Technology, VIT- University, Vellore, India
| | - Hatem Zayed
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar.
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Krishnamoorthy N, Gajendrarao P, Olivotto I, Yacoub M. Impact of disease-causing mutations on inter-domain interactions in cMyBP-C: a steered molecular dynamics study. J Biomol Struct Dyn 2016; 35:1916-1922. [DOI: 10.1080/07391102.2016.1199329] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Navaneethakrishnan Krishnamoorthy
- Qatar Cardiovascular Research Centre, Qatar Foundation, Doha, Qatar
- Division of Experimental Genetics, Sidra Medical and Research Centre, Doha, Qatar
- Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, UK
| | - Poornima Gajendrarao
- Qatar Cardiovascular Research Centre, Qatar Foundation, Doha, Qatar
- Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, UK
| | - Iacopo Olivotto
- Referral Centre for Myocardial Diseases, Careggi University Hospital, Florence, Italy
| | - Magdi Yacoub
- Qatar Cardiovascular Research Centre, Qatar Foundation, Doha, Qatar
- Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, UK
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14
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Krishnamoorthy N, Zayed H. Structural modeling of p.V31F variant in the aspartoacylase gene. Metab Brain Dis 2016; 31:723-6. [PMID: 26797702 DOI: 10.1007/s11011-016-9796-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 01/18/2016] [Indexed: 10/22/2022]
Abstract
Aspartoacylase (ASPA) is an abundant enzyme in the brain, which catalyzes the conversion of N-acetylaspartate into acetate and aspartate, deficiency in its activity leads to degeneration of the white matter of the brain and is a recognized cause of Canavan disease (CD), which affect children. Although genotype-phenotype correlation have been reported for Canavan disease patients, this relationships is still not straightforward. In this communication, we use molecular modeling to address the structural consequences resulting from the missense variant p.V31F in the ASPA enzyme, which we previously reported in a homozygous form in an Egyptian patient with infantile CD. This modeling suggests that this variant brings significant changes to the catalytic core by introducing structural flexibility through neighbouring key residues. In particular, it provides a molecular explanation for the pathogenic effect of this variant and provides a meaningful genotype-phonotype relationships. The mutational impact appears to have an influence on the function of the protein and initiates molecular event for the mechanism of the disease.
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Affiliation(s)
- Navaneethakrishnan Krishnamoorthy
- Cardiovascular Research Division, Sidra Medical and Research Centre, Qatar Foundation, Doha, Qatar
- Heart Science Centre, National Heart and Lung Institute, Imperial College London, Harefield, UK
| | - Hatem Zayed
- College of Health Sciences, Biomedical Program, Qatar University, Doha, Qatar.
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15
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Roma-Rodrigues C, Fernandes AR. Genetics of hypertrophic cardiomyopathy: advances and pitfalls in molecular diagnosis and therapy. APPLICATION OF CLINICAL GENETICS 2014; 7:195-208. [PMID: 25328416 PMCID: PMC4199654 DOI: 10.2147/tacg.s49126] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary disease of the cardiac muscle that occurs mainly due to mutations (>1,400 variants) in genes encoding for the cardiac sarcomere. HCM, the most common familial form of cardiomyopathy, affecting one in every 500 people in the general population, is typically inherited in an autosomal dominant pattern, and presents variable expressivity and age-related penetrance. Due to the morphological and pathological heterogeneity of the disease, the appearance and progression of symptoms is not straightforward. Most HCM patients are asymptomatic, but up to 25% develop significant symptoms, including chest pain and sudden cardiac death. Sudden cardiac death is a dramatic event, since it occurs without warning and mainly in younger people, including trained athletes. Molecular diagnosis of HCM is of the outmost importance, since it may allow detection of subjects carrying mutations on HCM-associated genes before development of clinical symptoms of HCM. However, due to the genetic heterogeneity of HCM, molecular diagnosis is difficult. Currently, there are mainly four techniques used for molecular diagnosis of HCM, including Sanger sequencing, high resolution melting, mutation detection using DNA arrays, and next-generation sequencing techniques. Application of these methods has proven successful for identification of mutations on HCM-related genes. This review summarizes the features of these technologies, highlighting their strengths and weaknesses. Furthermore, current therapeutics for HCM patients are correlated with clinically observed phenotypes and are based on the alleviation of symptoms. This is mainly due to insufficient knowledge on the mechanisms involved in the onset of HCM. Tissue engineering alongside regenerative medicine coupled with nanotherapeutics may allow fulfillment of those gaps, together with screening of novel therapeutic drugs and target delivery systems.
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Affiliation(s)
- Catarina Roma-Rodrigues
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal
| | - Alexandra R Fernandes
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Campus de Caparica, Caparica, Portugal ; Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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16
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Abstract
Since Wallace Brigden first used the term 'cardiomyopathy' in 1952, this group of diseases has continued to attract the interest of clinicians, researchers, and importantly, patients. The past decade has seen a substantial accumulation of knowledge relating to various cardiomyopathies, which has partially lifted the mystery surrounding this topic.
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Affiliation(s)
- Magdi H Yacoub
- Qatar Cardiovascular Research Center, PO Box 5825, Doha, Qatar
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Pirolli D, Sciandra F, Bozzi M, Giardina B, Brancaccio A, De Rosa MC. Insights from molecular dynamics simulations: structural basis for the V567D mutation-induced instability of zebrafish alpha-dystroglycan and comparison with the murine model. PLoS One 2014; 9:e103866. [PMID: 25078606 PMCID: PMC4117597 DOI: 10.1371/journal.pone.0103866] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/03/2014] [Indexed: 11/19/2022] Open
Abstract
A missense amino acid mutation of valine to aspartic acid in 567 position of alpha-dystroglycan (DG), identified in dag1-mutated zebrafish, results in a reduced transcription and a complete absence of the protein. Lacking experimental structural data for zebrafish DG domains, the detailed mechanism for the observed mutation-induced destabilization of the DG complex and membrane damage, remained unclear. With the aim to contribute to a better clarification of the structure-function relationships featuring the DG complex, three-dimensional structural models of wild-type and mutant (V567D) C-terminal domain of alpha-DG from zebrafish were constructed by a template-based modelling approach. We then ran extensive molecular dynamics (MD) simulations to reveal the structural and dynamic properties of the C-terminal domain and to evaluate the effect of the single mutation on alpha-DG stability. A comparative study has been also carried out on our previously generated model of murine alpha-DG C-terminal domain including the I591D mutation, which is topologically equivalent to the V567D mutation found in zebrafish. Trajectories from MD simulations were analyzed in detail, revealing extensive structural disorder involving multiple beta-strands in the mutated variant of the zebrafish protein whereas local effects have been detected in the murine protein. A biochemical analysis of the murine alpha-DG mutant I591D confirmed a pronounced instability of the protein. Taken together, the computational and biochemical analysis suggest that the V567D/I591D mutation, belonging to the G beta-strand, plays a key role in inducing a destabilization of the alpha-DG C-terminal Ig-like domain that could possibly affect and propagate to the entire DG complex. The structural features herein identified may be of crucial help to understand the molecular basis of primary dystroglycanopathies.
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Affiliation(s)
- Davide Pirolli
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Francesca Sciandra
- Istituto di Chimica del Riconoscimento Molecolare (ICRM) - CNR c/o Università Cattolica del Sacro Cuore, Rome, Italy
| | - Manuela Bozzi
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Bruno Giardina
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Rome, Italy
- Istituto di Chimica del Riconoscimento Molecolare (ICRM) - CNR c/o Università Cattolica del Sacro Cuore, Rome, Italy
| | - Andrea Brancaccio
- Istituto di Chimica del Riconoscimento Molecolare (ICRM) - CNR c/o Università Cattolica del Sacro Cuore, Rome, Italy
| | - Maria Cristina De Rosa
- Istituto di Chimica del Riconoscimento Molecolare (ICRM) - CNR c/o Università Cattolica del Sacro Cuore, Rome, Italy
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18
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Finley NL, Cuperman TI. Cardiac myosin binding protein-C: a structurally dynamic regulator of myocardial contractility. Pflugers Arch 2014; 466:433-8. [PMID: 24469349 DOI: 10.1007/s00424-014-1451-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/10/2014] [Accepted: 01/14/2014] [Indexed: 11/28/2022]
Abstract
Cardiac myosin binding protein-C (cMyBP-C) is a modular protein anchored to the thick filament through interactions mediated by its C-terminal region. The N-terminal region of cMyBPC-C regulates myocardial contractility by modifying actin-myosin association. Phosphorylation of the N-terminal region diminishes cMyBP-C's capacity to regulate actin-myosin function. Despite a substantial body of literature, many issues remain unclear regarding the structural and functional roles of cMyBP-C. While no high-resolution structures of the intact protein exist, crystallographic and nuclear magnetic resonance (NMR) structures of isolated N-terminal domains provide important molecular details regarding cMyBP-C's role in controlling contractility. In this review, we summarize the emerging structural understanding of cMyBP-C with a particular emphasis placed on describing how its dynamic molecular interactions with both thin and thick filament proteins likely contribute to contractile regulation. Furthermore, we discuss the future directions and strategies by which we may improve the mechanistic understanding of its role in modulating cardiac muscle contraction.
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Affiliation(s)
- Natosha L Finley
- The Cell, Molecular, and Structural Biology Program, Department of Microbiology, Miami University, 700 East High Street, 32 Pearson Hall, Oxford, OH, 45056, USA,
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