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Simonides W, Tijsma A, Boelen A, Jongejan R, de Rijke Y, Peeters R, Dentice M, Salvatore D, Muller A. Divergent Thyroid Hormone Levels in Plasma and Left Ventricle of the Heart in Compensated and Decompensated Cardiac Hypertrophy Induced by Chronic Adrenergic Stimulation in Mice. Metabolites 2023; 13:metabo13020308. [PMID: 36837927 PMCID: PMC9960204 DOI: 10.3390/metabo13020308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/05/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Chronic hemodynamic overload of the heart induces ventricular hypertrophy that may be either compensatory or progress to decompensation and heart failure. The gradual impairment of ventricular function is, at least in part, the result of a reduction of cardiac thyroid-hormone (TH) action. Here, we examined the proposed roles of increased cardiac expression of the TH-inactivating enzyme deiodinase type 3 (D3) and reduced plasma TH levels in diminishing cardiac TH levels. Using minipumps, mice were infused for one and two weeks with isoproterenol (ISO) alone or in combination with phenylephrine (PE). Remodeling of the heart induced by these adrenergic agonists was assessed by echocardiography. Left ventricular (LV) tissue and plasma TH levels (T4 and T3) were determined using liquid chromatography-tandem mass spectrometry. LV D3 activity was determined by conversion of radiolabeled substrate and quantification following HPLC. The results show that ISO induced compensated LV hypertrophy with maintained cardiac output. Plasma levels of T4 and T3 remained normal, but LV hormone levels were reduced by approximately 30% after two weeks, while LV D3 activity was not significantly increased. ISO + PE induced decompensated LV hypertrophy with diminished cardiac output. Plasma levels of T4 and T3 were substantially reduced after one and two weeks, together with a more than 50% reduction of hormone levels in the LV. D3 activity was increased after one week and returned to control levels after two weeks. These data show for the first time that relative to controls, decompensated LV hypertrophy with diminished cardiac output is associated with a greater reduction of cardiac TH levels than compensated hypertrophy with maintained cardiac output. LV D3 activity is unlikely to account for these reductions after two weeks in either condition. Whereas the mechanism of the mild reduction in compensated hypertrophy is unclear, changes in systemic TH homeostasis appear to determine the marked drop in LV TH levels and associated impairment of ventricular function in decompensated hypertrophy.
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Affiliation(s)
- Warner Simonides
- Department of Physiology, Amsterdam UMC, Vrije Universiteit, De Boelelaan 1118, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, 1081 HZ Amsterdam, The Netherlands
- Correspondence: (W.S.); (A.M.)
| | - Alice Tijsma
- Department of Physiology, Amsterdam UMC, Vrije Universiteit, De Boelelaan 1118, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, 1081 HZ Amsterdam, The Netherlands
| | - Anita Boelen
- Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Rutchanna Jongejan
- Department of Clinical Chemistry, Erasmus MC University Medical Center, Dr. Molewaterplein 40, 3000 CA Rotterdam, The Netherlands
| | - Yolanda de Rijke
- Department of Clinical Chemistry, Erasmus MC University Medical Center, Dr. Molewaterplein 40, 3000 CA Rotterdam, The Netherlands
| | - Robin Peeters
- Department of Internal Medicine, Erasmus MC University Medical Center, Dr. Molewaterplein 40, 3000 CA Rotterdam, The Netherlands
| | - Monica Dentice
- Department of Clinical Medicine and Surgery, University of Naples “Federico II”, Via Pansini 5, 80131 Naples, Italy
| | - Domenico Salvatore
- Department of Public Health, University of Naples “Federico II”, Via Pansini 5, 80131 Naples, Italy
| | - Alice Muller
- Department of Physiology, Amsterdam UMC, Vrije Universiteit, De Boelelaan 1118, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, 1081 HZ Amsterdam, The Netherlands
- Correspondence: (W.S.); (A.M.)
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2
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Helman TJ, Headrick JP, Vider J, Peart JN, Stapelberg NJC. Sex-specific behavioral, neurobiological, and cardiovascular responses to chronic social stress in mice. J Neurosci Res 2022; 100:2004-2027. [PMID: 36059192 DOI: 10.1002/jnr.25115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 07/19/2022] [Accepted: 07/22/2022] [Indexed: 02/06/2023]
Abstract
Psychosocial stress promotes and links mood and cardiovascular disorders in a sex-specific manner. However, findings in animal models are equivocal, in some cases opposing human dimorphisms. We examined central nervous system (CNS), behavioral, endocrine, cardiac, and hepatic outcomes in male or female C57Bl/6 mice subjected to chronic social stress (56 days of social isolation, with intermittent social confrontation encounters twice daily throughout the final 20 days). Females exhibited distinct physiological and behavioral changes, including relative weight loss, and increases in coronary resistance, hepatic inflammation, and thigmotaxic behavior in the open field. Males evidence reductions in coronary resistance and cardiac ischemic tolerance, with increased circulating and hippocampal monoamine levels and emerging anhedonia. Shared CNS gene responses include reduced hippocampal Maoa and increased Htr1b expression, while unique responses include repression of hypothalamic Ntrk1 and upregulation of cortical Nrf2 and Htr1b in females; and repression of hippocampal Drd1 and hypothalamic Gabra1 and Oprm in males. Declining cardiac stress resistance in males was associated with repression of cardiac leptin levels and metabolic, mitochondrial biogenesis, and anti-inflammatory gene expression. These integrated data reveal distinct biological responses to social stress in males and females, and collectively evidence greater biological disruption or allostatic load in females (consistent with propensities to stress-related mood and cardiovascular disorders in humans). Distinct stress biology, and molecular to organ responses, emphasize the importance of sex-specific mechanisms and potential approaches to stress-dependent disease.
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Affiliation(s)
- Tessa J Helman
- School of Pharmacy and Medical Sciences, Griffith University, Southport, Queensland, Australia
| | - John P Headrick
- School of Pharmacy and Medical Sciences, Griffith University, Southport, Queensland, Australia
| | - Jelena Vider
- School of Pharmacy and Medical Sciences, Griffith University, Southport, Queensland, Australia
| | - Jason N Peart
- School of Pharmacy and Medical Sciences, Griffith University, Southport, Queensland, Australia
| | - Nicolas J C Stapelberg
- Faculty of Health Sciences and Medicine, Bond University, Robina, Queensland, Australia.,Gold Coast Hospital and Health Service, Southport, Queensland, Australia
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3
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Chronic isoprenaline/phenylephrine vs. exclusive isoprenaline stimulation in mice: critical contribution of alpha 1-adrenoceptors to early cardiac stress responses. Basic Res Cardiol 2022; 117:15. [PMID: 35286475 PMCID: PMC8921177 DOI: 10.1007/s00395-022-00920-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 02/04/2022] [Accepted: 02/07/2022] [Indexed: 01/31/2023]
Abstract
Hyperactivity of the sympathetic nervous system is a major driver of cardiac remodeling, exerting its effects through both α-, and β-adrenoceptors (α-, β-ARs). As the relative contribution of subtype α1-AR to cardiac stress responses remains poorly investigated, we subjected mice to either subcutaneous perfusion with the β-AR agonist isoprenaline (ISO, 30 mg/kg × day) or to a combination of ISO and the stable α1-AR agonist phenylephrine (ISO/PE, 30 mg/kg × day each). Telemetry analysis revealed similar hemodynamic responses under both ISO and ISO/PE treatment i.e., permanently increased heart rates and only transient decreases in mean blood pressure during the first 24 h. Echocardiography and single cell analysis after 1 week of exposure showed that ISO/PE-, but not ISO-treated animals established α1-AR-mediated inotropic responsiveness to acute adrenergic stimulation. Morphologically, additional PE perfusion limited concentric cardiomyocyte growth and enhanced cardiac collagen deposition during 7 days of treatment. Time-course analysis demonstrated a diverging development in transcriptional patterns at day 4 of treatment i.e., increased expression of selected marker genes Xirp2, Nppa, Tgfb1, Col1a1, Postn under chronic ISO/PE treatment which was either less pronounced or absent in the ISO group. Transcriptome analyses at day 4 via RNA sequencing demonstrated that additional PE treatment caused a marked upregulation of genes allocated to extracellular matrix and fiber organization along with a more pronounced downregulation of genes involved in metabolic processes, muscle adaptation and cardiac electrophysiology. Consistently, transcriptome changes under ISO/PE challenge more effectively recapitulated early transcriptional alterations in pressure overload-induced experimental heart failure and in human hypertrophic cardiomyopathy.
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4
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Giles J, Fitzsimons DP, Patel JR, Knudtsen C, Neuville Z, Moss RL. cMyBP-C phosphorylation modulates the time-dependent slowing of unloaded shortening in murine skinned myocardium. J Gen Physiol 2021; 153:e202012782. [PMID: 33566084 PMCID: PMC7879488 DOI: 10.1085/jgp.202012782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/14/2021] [Indexed: 11/20/2022] Open
Abstract
In myocardium, phosphorylation of cardiac myosin-binding protein-C (cMyBP-C) is thought to modulate the cooperative activation of the thin filament by binding to myosin and/or actin, thereby regulating the probability of cross-bridge binding to actin. At low levels of Ca2+ activation, unloaded shortening velocity (Vo) in permeabilized cardiac muscle is comprised of an initial high-velocity phase and a subsequent low-velocity phase. The velocities in these phases scale with the level of activation, culminating in a single high-velocity phase (Vmax) at saturating Ca2+. To test the idea that cMyBP-C phosphorylation contributes to the activation dependence of Vo, we measured Vo before and following treatment with protein kinase A (PKA) in skinned trabecula isolated from mice expressing either wild-type cMyBP-C (tWT), nonphosphorylatable cMyBP-C (t3SA), or phosphomimetic cMyBP-C (t3SD). During maximal Ca2+ activation, Vmax was monophasic and not significantly different between the three groups. Although biphasic shortening was observed in all three groups at half-maximal activation under control conditions, the high- and low-velocity phases were faster in the t3SD myocardium compared with values obtained in either tWT or t3SA myocardium. Treatment with PKA significantly accelerated both the high- and low-velocity phases in tWT myocardium but had no effect on Vo in either the t3SD or t3SA myocardium. These results can be explained in terms of a model in which the level of cMyBP-C phosphorylation modulates the extent and rate of cooperative spread of myosin binding to actin.
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Affiliation(s)
- Jasmine Giles
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, and the University of Wisconsin Cardiovascular Research Center, Madison, WI
| | - Daniel P. Fitzsimons
- Department of Animal, Veterinary and Food Sciences, College of Agricultural and Life Sciences, University of Idaho, Moscow, ID
| | - Jitandrakumar R. Patel
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, and the University of Wisconsin Cardiovascular Research Center, Madison, WI
| | - Chloe Knudtsen
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, and the University of Wisconsin Cardiovascular Research Center, Madison, WI
| | - Zander Neuville
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, and the University of Wisconsin Cardiovascular Research Center, Madison, WI
| | - Richard L. Moss
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, and the University of Wisconsin Cardiovascular Research Center, Madison, WI
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5
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Li J, Mamidi R, Doh CY, Holmes JB, Bharambe N, Ramachandran R, Stelzer JE. AAV9 gene transfer of cMyBPC N-terminal domains ameliorates cardiomyopathy in cMyBPC-deficient mice. JCI Insight 2020; 5:130182. [PMID: 32750038 PMCID: PMC7526450 DOI: 10.1172/jci.insight.130182] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/29/2020] [Indexed: 01/05/2023] Open
Abstract
Decreased cardiac myosin-binding protein C (cMyBPC) expression due to inheritable mutations is thought to contribute to the hypertrophic cardiomyopathy (HCM) phenotype, suggesting that increasing cMyBPC content is of therapeutic benefit. In vitro assays show that cMyBPC N-terminal domains (NTDs) contain structural elements necessary and sufficient to modulate actomyosin interactions, but it is unknown if they can regulate in vivo myocardial function. To test whether NTDs can recapitulate the effects of full-length (FL) cMyBPC in rescuing cardiac function in a cMyBPC-null mouse model of HCM, we assessed the efficacy of AAV9 gene transfer of a cMyBPC NTD that contained domains C0C2 and compared its therapeutic potential with AAV9-FL gene replacement. AAV9 vectors were administered systemically at neonatal day 1, when early-onset disease phenotypes begin to manifest. A comprehensive analysis of in vivo and in vitro function was performed following cMyBPC gene transfer. Our results show that a systemic injection of AAV9-C0C2 significantly improved cardiac function (e.g., 52.24 ± 1.69 ejection fraction in the C0C2-treated group compared with 40.07 ± 1.97 in the control cMyBPC–/– group, P < 0.05) and reduced the histopathologic signs of cardiomyopathy. Furthermore, C0C2 significantly slowed and normalized the accelerated cross-bridge kinetics found in cMyBPC–/– control myocardium, as evidenced by a 32.41% decrease in the rate of cross-bridge detachment (krel). Results indicate that C0C2 can rescue biomechanical defects of cMyBPC deficiency and that the NTD may be a target region for therapeutic myofilament kinetic manipulation. Cardiac function improves following AAV9-mediated delivery of the C0C2 domains of cardiac myosin-binding protein C in a mouse model of hypertrophic cardiomyopathy.
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Nabiev SR, Kopylova GV, Shchepkin DV. The Effect of Cardiac Myosin-Binding Protein C on Calcium Regulation of the Actin–Myosin Interaction Depends on Myosin Light Chain Isoforms. Biophysics (Nagoya-shi) 2019. [DOI: 10.1134/s000635091905018x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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7
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Ahern BM, Levitan BM, Veeranki S, Shah M, Ali N, Sebastian A, Su W, Gong MC, Li J, Stelzer JE, Andres DA, Satin J. Myocardial-restricted ablation of the GTPase RAD results in a pro-adaptive heart response in mice. J Biol Chem 2019; 294:10913-10927. [PMID: 31147441 DOI: 10.1074/jbc.ra119.008782] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/16/2019] [Indexed: 12/25/2022] Open
Abstract
Existing therapies to improve heart function target β-adrenergic receptor (β-AR) signaling and Ca2+ handling and often lead to adverse outcomes. This underscores an unmet need for positive inotropes that improve heart function without any adverse effects. The GTPase Ras associated with diabetes (RAD) regulates L-type Ca2+ channel (LTCC) current (ICa,L). Global RAD-knockout mice (gRAD-/-) have elevated Ca2+ handling and increased cardiac hypertrophy, but RAD is expressed also in noncardiac tissues, suggesting the possibility that pathological remodeling is due also to noncardiac effects. Here, we engineered a myocardial-restricted inducible RAD-knockout mouse (RADΔ/Δ). Using an array of methods and techniques, including single-cell electrophysiological and calcium transient recordings, echocardiography, and radiotelemetry monitoring, we found that RAD deficiency results in a sustained increase of inotropy without structural or functional remodeling of the heart. ICa,L was significantly increased, with RAD loss conferring a β-AR-modulated phenotype on basal ICa,L Cardiomyocytes from RADΔ/Δ hearts exhibited enhanced cytosolic Ca2+ handling, increased contractile function, elevated sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2a) expression, and faster lusitropy. These results argue that myocardial RAD ablation promotes a beneficial elevation in Ca2+ dynamics, which would obviate a need for increased β-AR signaling to improve cardiac function.
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Affiliation(s)
| | - Bryana M Levitan
- Department of Physiology,; Gill Heart and Vascular Institute, and
| | - Sudhakar Veeranki
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536 and
| | | | - Nemat Ali
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536 and
| | | | | | | | - Jiayang Li
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Douglas A Andres
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536 and.
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8
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Giles J, Patel JR, Miller A, Iverson E, Fitzsimons D, Moss RL. Recovery of left ventricular function following in vivo reexpression of cardiac myosin binding protein C. J Gen Physiol 2019; 151:77-89. [PMID: 30573635 PMCID: PMC6314388 DOI: 10.1085/jgp.201812238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/27/2018] [Indexed: 01/26/2023] Open
Abstract
The loss of cardiac myosin binding protein C (cMyBP-C) results in left ventricular dilation, cardiac hypertrophy, and impaired ventricular function in both constitutive and conditional cMyBP-C knockout (MYBPC3 null) mice. It remains unclear whether the structural and functional phenotypes expressed in the MYBPC3 null mouse are reversible, which is an important question, since reduced expression of cMyBP-C is an important cause of hypertrophic cardiomyopathy in humans. To investigate this question, we generated a cardiac-specific transgenic mouse model using a Tet-Off inducible system to permit the controlled expression of WT cMyBP-C on the MYBPC3 null background. Functional Tet-Off mice expressing WT cMyBP-C (FT-WT) were generated by crossing tetracycline transactivator mice with responder mice carrying the WT cMyBP-C transgene. Prior to dietary doxycycline administration, cMyBP-C was expressed at normal levels in FT-WT myocardium, which exhibited similar levels of steady-state force and in vivo left ventricular function as WT mice. Introduction of dietary doxycycline for four weeks resulted in a partial knockdown of cMyBP-C expression and commensurate impairment of systolic and diastolic function to levels approaching those observed in MYBPC 3 null mice. Subsequent withdrawal of doxycycline from the diet resulted in the reexpression of cMyBP-C to levels comparable to those observed in WT mice, along with near-complete recovery of in vivo ventricular function. These results show that the cardiac phenotypes associated with MYBPC3 null mice are reversible. Our work also validates the use of the Tet-Off inducible system as a means to study the mechanisms underlying hypertrophic cardiomyopathy.
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Affiliation(s)
- Jasmine Giles
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
| | - Jitandrakumar R Patel
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
- University of Wisconsin Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
| | - Adam Miller
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
| | - Elizabeth Iverson
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
| | - Daniel Fitzsimons
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
- University of Wisconsin Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
| | - Richard L Moss
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
- University of Wisconsin Cardiovascular Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
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9
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Doh CY, Li J, Mamidi R, Stelzer JE. The HCM-causing Y235S cMyBPC mutation accelerates contractile function by altering C1 domain structure. Biochim Biophys Acta Mol Basis Dis 2019; 1865:661-677. [PMID: 30611859 DOI: 10.1016/j.bbadis.2019.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/18/2018] [Accepted: 01/02/2019] [Indexed: 12/20/2022]
Abstract
Mutations in cardiac myosin binding protein C (cMyBPC) are a major cause of hypertrophic cardiomyopathy (HCM). In particular, a single amino acid substitution of tyrosine to serine at residue 237 in humans (residue 235 in mice) has been linked to HCM with strong disease association. Although cMyBPC truncations, deletions and insertions, and frame shift mutations have been studied, relatively little is known about the functional consequences of missense mutations in cMyBPC. In this study, we characterized the functional and structural effects of the HCM-causing Y235S mutation by performing mechanical experiments and molecular dynamics simulations (MDS). cMyBPC null mouse myocardium was virally transfected with wild-type (WT) or Y235S cMyBPC (KOY235S). We found that Y235S cMyBPC was properly expressed and incorporated into the cardiac sarcomere, suggesting that the mechanism of disease of the Y235S mutation is not haploinsufficiency or poison peptides. Mechanical experiments in detergent-skinned myocardium isolated from KOY235S hearts revealed hypercontractile behavior compared to KOWT hearts, evidenced by accelerated cross-bridge kinetics and increased Ca2+ sensitivity of force generation. In addition, MDS revealed that the Y235S mutation causes alterations in important intramolecular interactions, surface conformations, and electrostatic potential of the C1 domain of cMyBPC. Our combined in vitro and in silico data suggest that the Y235S mutation directly disrupts internal and surface properties of the C1 domain of cMyBPC, which potentially alters its ligand-binding interactions. These molecular changes may underlie the mechanism for hypercontractile cross-bridge behavior, which ultimately results in the development of cardiac hypertrophy and in vivo cardiac dysfunction.
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Affiliation(s)
- Chang Yoon Doh
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Jiayang Li
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
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10
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Mamidi R, Li J, Doh CY, Holmes JB, Stelzer JE. Lost in translation: Interpreting cardiac muscle mechanics data in clinical practice. Arch Biochem Biophys 2018; 662:213-218. [PMID: 30576628 DOI: 10.1016/j.abb.2018.12.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/25/2018] [Accepted: 12/17/2018] [Indexed: 01/10/2023]
Abstract
Current inotropic therapies improve systolic function in heart failure patients but also elicit undesirable side effects such as arrhythmias and increased intracellular Ca2+ transients. In order to maintain myocyte Ca2+ homeostasis, the increased cytosolic Ca2+ needs to be actively transported back to sarcoplasmic reticulum leading to depleted ATP reserves. Thus, an emerging approach is to design sarcomere-based treatments to correct impaired contractility via a direct and allosteric modulation of myosin's intrinsic force-generating behavior -a concept that potentially avoids the "off-target" effects. To achieve this goal, various biophysical approaches are utilized to investigate the mechanistic impact of sarcomeric modulators but information derived from diverse approaches is not fully integrated into therapeutic applications. This is in part due to the lack of information that provides a coherent connecting link between biophysical data to in vivo function. Hence, our ability to clearly discern the drug-mediated impact on whole-heart function is diminished. Reducing this translational barrier can significantly accelerate clinical progress related to sarcomere-based therapies by optimizing drug-dosing and treatment duration protocols based on information obtained from biophysical studies. Therefore, we attempt to link biophysical mechanical measurements obtained in isolated cardiac muscle and in vivo contractile function.
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Affiliation(s)
- Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Jiayang Li
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Chang Yoon Doh
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Joshua B Holmes
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.
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11
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Li J, Gresham KS, Mamidi R, Doh CY, Wan X, Deschenes I, Stelzer JE. Sarcomere-based genetic enhancement of systolic cardiac function in a murine model of dilated cardiomyopathy. Int J Cardiol 2018; 273:168-176. [PMID: 30279005 DOI: 10.1016/j.ijcard.2018.09.073] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/27/2018] [Accepted: 09/20/2018] [Indexed: 01/28/2023]
Abstract
Diminished cardiac contractile function is a characteristic feature of dilated cardiomyopathy (DCM) and many other heart failure (HF) causing etiologies. We tested the hypothesis that targeting the sarcomere to increase cardiac contractility can effectively prevent the DCM phenotype in muscle-LIM protein knockout (MLP-/-) mice. The ablation of cardiac myosin binding protein C (MYBPC3-/-) protected the MLP-/- mice from developing the DCM phenotype. We examined the in vivo cardiac function and morphology of the resultant mouse model lacking both MLP and MYBPC3 (DKO) by echocardiography and pressure-volume catheterization and found a significant reduction in hypertrophy, as evidenced by normalized wall thickness and chamber dimensions, and improved systolic function, as evidenced by enhanced ejection fraction (~26% increase compared MLP-/- mice) and rate of pressure development (DKO 7851.0 ± 504.8 vs. MLP-/- 4496.4 ± 196.8 mmHg/s). To investigate the molecular basis for the improved DKO phenotype we performed mechanical experiments in skinned myocardium isolated from WT and the individual KO mice. Skinned myocardium isolated from DKO mice displayed increased Ca2+ sensitivity of force generation, and significantly accelerated rate of cross-bridge detachment (+63% compared to MLP-/-) and rate of XB recruitment (+58% compared to MLP-/-) at submaximal Ca2+ activations. The in vivo and in vitro functional enhancement of DKO mice demonstrates that enhancing the sarcomeric contractility can be cardioprotective in HF characterized by reduced cardiac output, such as in cases of DCM.
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Affiliation(s)
- Jiayang Li
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Kenneth S Gresham
- Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States of America
| | - Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Chang Yoon Doh
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Xiaoping Wan
- The Heart and Vascular Research Center, Metro Health, Cleveland, OH, United States of America
| | - Isabelle Deschenes
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America; The Heart and Vascular Research Center, Metro Health, Cleveland, OH, United States of America
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America.
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12
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Mamidi R, Li J, Doh CY, Verma S, Stelzer JE. Impact of the Myosin Modulator Mavacamten on Force Generation and Cross-Bridge Behavior in a Murine Model of Hypercontractility. J Am Heart Assoc 2018; 7:e009627. [PMID: 30371160 PMCID: PMC6201428 DOI: 10.1161/jaha.118.009627] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/27/2018] [Indexed: 01/09/2023]
Abstract
Background Recent studies suggest that mavacamten (Myk461), a small myosin-binding molecule, decreases hypercontractility in myocardium expressing hypertrophic cardiomyopathy-causing missense mutations in myosin heavy chain. However, the predominant feature of most mutations in cardiac myosin binding protein-C ( cMyBPC ) that cause hypertrophic cardiomyopathy is reduced total cMyBPC expression, and the impact of Myk461 on cMyBPC -deficient myocardium is currently unknown. Methods and Results We measured the impact of Myk461 on steady-state and dynamic cross-bridge ( XB ) behavior in detergent-skinned mouse wild-type myocardium and myocardium lacking cMyBPC (knockout (KO)). KO myocardium exhibited hypercontractile XB behavior as indicated by significant accelerations in rates of XB detachment (krel) and recruitment (kdf) at submaximal Ca2+ activations. Incubation of KO and wild-type myocardium with Myk461 resulted in a dose-dependent force depression, and this impact was more pronounced at low Ca2+ activations. Interestingly, Myk461-induced force depressions were less pronounced in KO myocardium, especially at low Ca2+ activations, which may be because of increased acto-myosin XB formation and potential disruption of super-relaxed XB s in KO myocardium. Additionally, Myk461 slowed krel in KO myocardium but not in wild-type myocardium, indicating increased XB " on" time. Furthermore, the greater degree of Myk461-induced slowing in kdf and reduction in XB recruitment magnitude in KO myocardium normalized the XB behavior back to wild-type levels. Conclusions This is the first study to demonstrate that Myk461-induced force depressions are modulated by cMyBPC expression levels in the sarcomere, and emphasizes that clinical use of Myk461 may need to be optimized based on the molecular trigger that underlies the hypertrophic cardiomyopathy phenotype.
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Affiliation(s)
- Ranganath Mamidi
- Department of Physiology and BiophysicsSchool of MedicineCase Western Reserve UniversityClevelandOH
| | - Jiayang Li
- Department of Physiology and BiophysicsSchool of MedicineCase Western Reserve UniversityClevelandOH
| | - Chang Yoon Doh
- Department of Physiology and BiophysicsSchool of MedicineCase Western Reserve UniversityClevelandOH
| | - Sujeet Verma
- Department of Horticulture SciencesIFAS, Gulf Coast Research and Education CenterUniversity of FloridaWimauma
| | - Julian E. Stelzer
- Department of Physiology and BiophysicsSchool of MedicineCase Western Reserve UniversityClevelandOH
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Mamidi R, Li J, Gresham KS, Verma S, Doh CY, Li A, Lal S, Dos Remedios CG, Stelzer JE. Dose-Dependent Effects of the Myosin Activator Omecamtiv Mecarbil on Cross-Bridge Behavior and Force Generation in Failing Human Myocardium. Circ Heart Fail 2017; 10:CIRCHEARTFAILURE.117.004257. [PMID: 29030372 DOI: 10.1161/circheartfailure.117.004257] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 09/12/2017] [Indexed: 01/10/2023]
Abstract
BACKGROUND Omecamtiv mecarbil (OM) enhances systolic function in vivo by directly binding the myosin cross-bridges (XBs) in the sarcomere. However, the mechanistic details governing OM-induced modulation of XB behavior in failing human myocardium are unclear. METHODS AND RESULTS The effects of OM on steady state and dynamic XB behavior were measured in chemically skinned myocardial preparations isolated from human donor and heart failure (HF) left ventricle. HF myocardium exhibited impaired contractile function as evidenced by reduced maximal force, magnitude of XB recruitment (Pdf), and a slowed rate of XB detachment (krel) at submaximal Ca2+ activations. Ca2+ sensitivity of force generation (pCa50) was higher in HF myocardium when compared with donor myocardium, both prior to and after OM incubations. OM incubation (0.5 and 1.0 μmol/L) enhanced force generation at submaximal Ca2+ activations in a dose-dependent manner. Notably, OM induced a slowing in krel with 1.0 μmol/L OM but not with 0.5 μmol/L OM in HF myocardium. Additionally, OM exerted other differential effects on XB behavior in HF myocardium as evidenced by a greater enhancement in Pdf and slowing in the time course of cooperative XB recruitment (Trec), which collectively prolonged achievement of peak force development (Tpk), compared with donor myocardium. CONCLUSIONS Our findings demonstrate that OM augments force generation but also prolongs the time course of XB transitions to force-bearing states in remodeled HF myocardium, which may extend the systolic ejection time in vivo. Optimal OM dosing is critical for eliciting enhanced systolic function without excessive prolongation of systolic ejection time, which may compromise diastolic filling.
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Affiliation(s)
- Ranganath Mamidi
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Jiayang Li
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Kenneth S Gresham
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Sujeet Verma
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Chang Yoon Doh
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Amy Li
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Sean Lal
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Cristobal G Dos Remedios
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.)
| | - Julian E Stelzer
- From the Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH (R.M., J.L., C.Y.D., J.E.S.); Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA (K.S.G); Department of Horticulture Sciences, IFAS, Gulf Coast Research and Education Center, University of Florida, Wimauma (S.V.); Sydney Heart Bank, Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Australia (A.L., S.L., C.G.d.R.).
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