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Hantz ER, Tikunova SB, Belevych N, Davis JP, Reiser PJ, Lindert S. Targeting Troponin C with Small Molecules Containing Diphenyl Moieties: Calcium Sensitivity Effects on Striated Muscles and Structure-Activity Relationship. J Chem Inf Model 2023; 63:3462-3473. [PMID: 37204863 PMCID: PMC10496875 DOI: 10.1021/acs.jcim.3c00196] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Despite large investments from academia and industry, heart failure, which results from a disruption of the contractile apparatus, remains a leading cause of death. Cardiac muscle contraction is a calcium-dependent mechanism, which is regulated by the troponin protein complex (cTn) and specifically by the N-terminal domain of its calcium-binding subunit (cNTnC). There is an increasing need for the development of small molecules that increase calcium sensitivity without altering the systolic calcium concentration, thereby strengthening the cardiac function. Here, we examined the effect of our previously identified calcium-sensitizing small molecule, ChemBridge compound 7930079, in the context of several homologous muscle systems. The effect of this molecule on force generation in isolated cardiac trabeculae and slow skeletal muscle fibers was measured. Furthermore, we explored the use of Gaussian accelerated molecular dynamics in sampling highly predictive receptor conformations based on NMR-derived starting structures. Additionally, we took a rational computational approach for lead optimization based on lipophilic diphenyl moieties. This integrated structural-biochemical-physiological approach led to the identification of three novel low-affinity binders, which had similar binding affinities to the known positive inotrope trifluoperazine. The most potent identified calcium sensitizer was compound 16 with an apparent affinity of 117 ± 17 μM.
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Affiliation(s)
- Eric R. Hantz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210
| | - Svetlana B. Tikunova
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210
| | - Natalya Belevych
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH 43210
| | - Jonathan P. Davis
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210
| | - Peter J. Reiser
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH 43210
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210
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2
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Hantz ER, Tikunova SB, Belevych N, Davis JP, Reiser PJ, Lindert S. Targeting Troponin C with Small Molecules Containing Diphenyl Moieties: Calcium Sensitivity Effects on Striated Muscle and Structure Activity Relationship. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.06.527323. [PMID: 36798160 PMCID: PMC9934531 DOI: 10.1101/2023.02.06.527323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Despite large investments from academia and industry, heart failure, which results from a disruption of the contractile apparatus, remains a leading cause of death. Cardiac muscle contraction is a calcium-dependent mechanism, which is regulated by the troponin protein complex (cTn) and specifically by the N-terminal domain of its calcium binding subunit (cNTnC). There is an increasing need for the development of small molecules that increase calcium sensitivity without altering systolic calcium concentration, thereby strengthening cardiac function. Here, we examined the effect of our previously identified calcium sensitizing small molecule, ChemBridge compound 7930079, in the context of several homologous muscle systems. The effect of this molecule on force generation in isolated cardiac trabeculae and slow skeletal muscle fibers was measured. Furthermore, we explored the use of Gaussian accelerated molecular dynamics in sampling highly predictive receptor conformations based on NMR derived starting structures. Additionally, we took a rational computational approach for lead optimization based on lipophilic diphenyl moieties. This led to the identification of three novel low affinity binders, which had similar binding affinities to known positive inotrope trifluoperazine. The most potent identified calcium sensitizer was compound 16 with an apparent affinity of 117 ± 17 μM .
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Affiliation(s)
- Eric R. Hantz
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210
| | - Svetlana B. Tikunova
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210
| | - Natalya Belevych
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH 43210
| | - Jonathan P. Davis
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210
| | - Peter J. Reiser
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH 43210
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210,Correspondence to: Department of Chemistry and Biochemistry, Ohio State University, 2114 Newman & Wolfrom Laboratory, 100 W. 18th Avenue, Columbus, OH 43210, 614-292-8284 (office), 614-292-1685 (fax),
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3
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Hantz ER, Lindert S. Computational Exploration and Characterization of Potential Calcium Sensitizing Mutations in Cardiac Troponin C. J Chem Inf Model 2022; 62:6201-6208. [PMID: 36383927 PMCID: PMC10497304 DOI: 10.1021/acs.jcim.2c01132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Calcium-dependent heart muscle contraction is regulated by the cardiac troponin protein complex (cTn) and specifically by the N-terminal domain of its calcium binding subunit (cNTnC). cNTnC contains one calcium binding site (site II), and altered calcium binding in this site has been studied for decades. It has been previously shown that cNTnC mutants, which increase calcium sensitization may have therapeutic benefits, such as restoring cardiac muscle contractility and functionality post-myocardial infarction events. Here, we computationally characterized eight mutations for their potential effects on calcium binding affinity in site II of cNTnC. We utilized two distinct methods to estimate calcium binding: adaptive steered molecular dynamics (ASMD) and thermodynamic integration (TI). We observed a sensitizing trend for all mutations based on the employed ASMD methodology. The TI results showed excellent agreement with experimentally known calcium binding affinities in wild-type cNTnC. Based on the TI results, five mutants were predicted to increase calcium sensitivity in site II. This study presents an interesting comparison of the two computational methods, which have both been shown to be valuable tools in characterizing the impacts of calcium sensitivity in mutant cNTnC systems.
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Affiliation(s)
- Eric R. Hantz
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, 43210
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, 43210
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4
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Cai F, Kampourakis T, Cockburn KT, Sykes BD. Drugging the Sarcomere, a Delicate Balance: Position of N-Terminal Charge of the Inhibitor W7. ACS Chem Biol 2022; 17:1495-1504. [PMID: 35649123 DOI: 10.1021/acschembio.2c00126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
W7 is a sarcomere inhibitor that decreases the calcium sensitivity of force development in cardiac muscle. W7 binds to the interface of the regulatory domain of cardiac troponin C (cNTnC) and the switch region of troponin I (cTnI), decreasing the binding of cTnI to cNTnC, presumably by electrostatic repulsion between the -NH3+ group of W7 and basic amino acids in cTnI. W7 analogs with a -CO2- tail are inactive. To evaluate the importance of the location of the charged -NH3+, we used a series of compounds W4, W6, W8, and W9, which have three less, one less, one more, and two more methylene groups in the tail region than W7. W6, W8, and W9 all bind tighter to cNTnC-cTnI chimera (cChimera) than W7, while W4 binds weaker. W4 and, strikingly, W6 have no effect on calcium sensitivity of force generation, while W8 and W9 decrease calcium sensitivity, but less than W7. The structures of the cChimera-W6 and cChimera-W8 complexes reveal that W6 and W8 bind to the same hydrophobic cleft as W7, with the aliphatic tail taking a similar route to the surface. NMR relaxation data show that internal flexibility in the tail of W7 is very limited. Alignment of the cChimera-W7 structure with the recent cryoEM structures of the cardiac sarcomere in the diastolic and systolic states reveals the critical location of the amino group. Small molecule induced structural changes can therefore affect the tightly balanced equilibrium between tethered components required for rapid contraction.
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Affiliation(s)
- Fangze Cai
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
| | - Thomas Kampourakis
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom
| | - Kieran T Cockburn
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
| | - Brian D Sykes
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
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5
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Coldren WH, Tikunova SB, Davis JP, Lindert S. Discovery of Novel Small-Molecule Calcium Sensitizers for Cardiac Troponin C: A Combined Virtual and Experimental Screening Approach. J Chem Inf Model 2020; 60:3648-3661. [PMID: 32633957 DOI: 10.1021/acs.jcim.0c00452] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Heart failure is a leading cause of death throughout the world and is triggered by a disruption of the cardiac contractile machinery. This machinery is regulated in a calcium-dependent manner by the protein complex troponin. Calcium binds to the N-terminal domain of cardiac troponin C (cNTnC) setting into motion the cascade of events leading to muscle contraction. Because of the severity and prevalence of heart failure, there is a strong need to develop small-molecule therapeutics designed to increase the calcium sensitivity of cardiac troponin in order to treat this devastating condition. Molecules that are able to stabilize an open configuration of cNTnC and additionally facilitate the binding of the cardiac troponin I (cTnI) switch peptide have the potential to enable increased calcium sensitization and strengthened cardiac function. Here, we employed a high throughput virtual screening methodology built upon the ability of computational docking to reproduce known experimental results and to accurately recognize cNTnC conformations conducive to small molecule binding using a receiver operator characteristic curve analysis. This approach combined with concurrent stopped-flow kinetic experimental verification led to the identification of a number of sensitizers, which slowed the calcium off-rate. An initial hit, compound 4, was identified with medium affinity (84 ± 30 μM). Through refinement, a calcium sensitizing agent, compound 5, with an apparent affinity of 1.45 ± 0.09 μM was discovered. This molecule is one of the highest affinity calcium sensitizers known to date.
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Affiliation(s)
- William H Coldren
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210, United States
| | - Svetlana B Tikunova
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, Ohio State University, Columbus, Ohio 43210, United States
| | - Jonathan P Davis
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, Ohio State University, Columbus, Ohio 43210, United States
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210, United States
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6
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Bowman JD, Coldren WH, Lindert S. Mechanism of Cardiac Troponin C Calcium Sensitivity Modulation by Small Molecules Illuminated by Umbrella Sampling Simulations. J Chem Inf Model 2019; 59:2964-2972. [PMID: 31141358 DOI: 10.1021/acs.jcim.9b00256] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cardiac troponin C (cTnC) binds intracellular calcium and subsequently cardiac troponin I (cTnI), initiating cardiac muscle contraction. Due to its role in contraction, cTnC has been a therapeutic target in the search for small molecules to treat conditions that interfere with normal muscle contraction like the heritable cardiomyopathies. Structural studies have shown the binding location of small molecules such as bepridil, dfbp-o, 3-methyldiphenylamine (DPA), and W7 to be a hydrophobic pocket in the regulatory domain of cTnC (cNTnC) but have not shown the influence of these small molecules on the energetics of opening this domain. Here we describe an application of an umbrella sampling method used to elucidate the impact these calcium sensitivity modulators have on the free energy of cNTnC hydrophobic patch opening. We found that all these molecules lowered the free energy of opening in the absence of the cTnI, with bepridil facilitating the least endergonic transformation. In the presence of cTnI, however, we saw a stabilization of the open configuration due to DPA and dfbp-o binding, and a destabilization of the open configuration imparted by bepridil and W7. Predicted poor binding molecule NSC34337 left the hydrophobic patch in under 3 ns in conventional MD simulations suggesting that only hydrophobic patch binders stabilized the open conformation. In conclusion, this study presents a novel approach to study the impact of small molecules on hydrophobic patch opening through umbrella sampling, and it proposes mechanisms for calcium sensitivity modulation.
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Affiliation(s)
- Jacob D Bowman
- Department of Chemistry and Biochemistry , Ohio State University , 2114 Newman & Wolfrom Laboratory, 100 West 18th Avenue , Columbus , Ohio 43210 , United States
| | - William H Coldren
- Department of Chemistry and Biochemistry , Ohio State University , 2114 Newman & Wolfrom Laboratory, 100 West 18th Avenue , Columbus , Ohio 43210 , United States
| | - Steffen Lindert
- Department of Chemistry and Biochemistry , Ohio State University , 2114 Newman & Wolfrom Laboratory, 100 West 18th Avenue , Columbus , Ohio 43210 , United States
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7
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Lu H, Chen I, Shimoda LA, Park Y, Zhang C, Tran L, Zhang H, Semenza GL. Chemotherapy-Induced Ca 2+ Release Stimulates Breast Cancer Stem Cell Enrichment. Cell Rep 2017; 18:1946-1957. [PMID: 28228260 DOI: 10.1016/j.celrep.2017.02.001] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/29/2016] [Accepted: 01/30/2017] [Indexed: 12/16/2022] Open
Abstract
Breast cancer stem cells (BCSCs) play a critical role in tumor recurrence and metastasis. Exposure of breast cancer cells to chemotherapy leads to an enrichment of BCSCs. Here, we find that chemotherapy induces the expression of glutathione S-transferase omega 1 (GSTO1), which is dependent on hypoxia-inducible factor 1 (HIF-1) and HIF-2. Knockdown of GSTO1 expression abrogates carboplatin-induced BCSC enrichment, decreases tumor initiation and metastatic capacity, and delays tumor recurrence after chemotherapy. GSTO1 interacts with the ryanodine receptor RYR1 and promotes calcium release from the endoplasmic reticulum. Increased cytosolic calcium levels activate PYK2 → SRC → STAT3 signaling, leading to increased expression of pluripotency factors and BCSC enrichment. HIF inhibition blocks chemotherapy-induced GSTO1 expression and BCSC enrichment. Combining HIF inhibitors with chemotherapy may improve clinical outcome in breast cancer.
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Affiliation(s)
- Haiquan Lu
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ivan Chen
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Larissa A Shimoda
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Youngrok Park
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Chuanzhao Zhang
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Linh Tran
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Huimin Zhang
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gregg L Semenza
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Departments of Pediatrics, Medicine, Oncology, Radiation Oncology, and Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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8
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Aprahamian ML, Tikunova SB, Price MV, Cuesta AF, Davis JP, Lindert S. Successful Identification of Cardiac Troponin Calcium Sensitizers Using a Combination of Virtual Screening and ROC Analysis of Known Troponin C Binders. J Chem Inf Model 2017; 57:3056-3069. [PMID: 29144742 DOI: 10.1021/acs.jcim.7b00536] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Calcium-dependent cardiac muscle contraction is regulated by the protein complex troponin. Calcium binds to the N-terminal domain of troponin C (cNTnC) which initiates the process of contraction. Heart failure is a consequence of a disruption of this process. With the prevalence of this condition, a strong need exists to find novel compounds to increase the calcium sensitivity of cNTnC. Desirable are small chemical molecules that bind to the interface between cTnC and the cTnI switch peptide and exhibit calcium sensitizing properties by possibly stabilizing cTnC in an open conformation. To identify novel drug candidates, we employed a structure-based drug discovery protocol that incorporated the use of a relaxed complex scheme (RCS). In preparation for the virtual screening, cNTnC conformations were identified based on their ability to correctly predict known cNTnC binders using a receiver operating characteristics analysis. Following a virtual screen of the National Cancer Institute's Developmental Therapeutic Program database, a small number of molecules were experimentally tested using stopped-flow kinetics and steady-state fluorescence titrations. We identified two novel compounds, 3-(4-methoxyphenyl)-6,7-chromanediol (NSC600285) and 3-(4-methylphenyl)-7,8-chromanediol (NSC611817), that show increased calcium sensitivity of cTnC in the presence of the regulatory domain of cTnI. The effects of NSC600285 and NSC611817 on the calcium dissociation rate was stronger than that of the known calcium sensitizer bepridil. Thus, we identified a 3-phenylchromane group as a possible key pharmacophore in the sensitization of cardiac muscle contraction. Building on this finding is of interest to researchers working on development of drugs for calcium sensitization.
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Affiliation(s)
- Melanie L Aprahamian
- Department of Chemistry and Biochemistry, Ohio State University , Columbus, Ohio 43210, United States
| | - Svetlana B Tikunova
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, Ohio State University , Columbus, Ohio 43210, United States
| | - Morgan V Price
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, Ohio State University , Columbus, Ohio 43210, United States
| | - Andres F Cuesta
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, Ohio State University , Columbus, Ohio 43210, United States
| | - Jonathan P Davis
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, Ohio State University , Columbus, Ohio 43210, United States
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, Ohio State University , Columbus, Ohio 43210, United States
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9
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Robertson IM, Pineda-Sanabria SE, Yan Z, Kampourakis T, Sun YB, Sykes BD, Irving M. Reversible Covalent Binding to Cardiac Troponin C by the Ca2+-Sensitizer Levosimendan. Biochemistry 2016; 55:6032-6045. [DOI: 10.1021/acs.biochem.6b00758] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ian M. Robertson
- Randall
Division of Cell and Molecular Biophysics and British Heart Foundation
Centre of Research Excellence, King’s College London, New Hunt’s
House, Guy’s Campus, London, SE1 1UL, U.K
- Department
of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Sandra E. Pineda-Sanabria
- Department
of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Ziqian Yan
- Randall
Division of Cell and Molecular Biophysics and British Heart Foundation
Centre of Research Excellence, King’s College London, New Hunt’s
House, Guy’s Campus, London, SE1 1UL, U.K
| | - Thomas Kampourakis
- Randall
Division of Cell and Molecular Biophysics and British Heart Foundation
Centre of Research Excellence, King’s College London, New Hunt’s
House, Guy’s Campus, London, SE1 1UL, U.K
| | - Yin-Biao Sun
- Randall
Division of Cell and Molecular Biophysics and British Heart Foundation
Centre of Research Excellence, King’s College London, New Hunt’s
House, Guy’s Campus, London, SE1 1UL, U.K
| | - Brian D. Sykes
- Department
of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Malcolm Irving
- Randall
Division of Cell and Molecular Biophysics and British Heart Foundation
Centre of Research Excellence, King’s College London, New Hunt’s
House, Guy’s Campus, London, SE1 1UL, U.K
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10
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Marques MDA, de Oliveira GAP. Cardiac Troponin and Tropomyosin: Structural and Cellular Perspectives to Unveil the Hypertrophic Cardiomyopathy Phenotype. Front Physiol 2016; 7:429. [PMID: 27721798 PMCID: PMC5033975 DOI: 10.3389/fphys.2016.00429] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/09/2016] [Indexed: 12/12/2022] Open
Abstract
Inherited myopathies affect both skeletal and cardiac muscle and are commonly associated with genetic dysfunctions, leading to the production of anomalous proteins. In cardiomyopathies, mutations frequently occur in sarcomeric genes, but the cause-effect scenario between genetic alterations and pathological processes remains elusive. Hypertrophic cardiomyopathy (HCM) was the first cardiac disease associated with a genetic background. Since the discovery of the first mutation in the β-myosin heavy chain, more than 1400 new mutations in 11 sarcomeric genes have been reported, awarding HCM the title of the “disease of the sarcomere.” The most common macroscopic phenotypes are left ventricle and interventricular septal thickening, but because the clinical profile of this disease is quite heterogeneous, these phenotypes are not suitable for an accurate diagnosis. The development of genomic approaches for clinical investigation allows for diagnostic progress and understanding at the molecular level. Meanwhile, the lack of accurate in vivo models to better comprehend the cellular events triggered by this pathology has become a challenge. Notwithstanding, the imbalance of Ca2+ concentrations, altered signaling pathways, induction of apoptotic factors, and heart remodeling leading to abnormal anatomy have already been reported. Of note, a misbalance of signaling biomolecules, such as kinases and tumor suppressors (e.g., Akt and p53), seems to participate in apoptotic and fibrotic events. In HCM, structural and cellular information about defective sarcomeric proteins and their altered interactome is emerging but still represents a bottleneck for developing new concepts in basic research and for future therapeutic interventions. This review focuses on the structural and cellular alterations triggered by HCM-causing mutations in troponin and tropomyosin proteins and how structural biology can aid in the discovery of new platforms for therapeutics. We highlight the importance of a better understanding of allosteric communications within these thin-filament proteins to decipher the HCM pathological state.
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Affiliation(s)
- Mayra de A Marques
- Programa de Biologia Estrutural, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Guilherme A P de Oliveira
- Programa de Biologia Estrutural, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
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11
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Baliño P, Ledesma JC, Aragon CMG. Role of CA2+/calmodulin on ethanol neurobehavioral effects. Psychopharmacology (Berl) 2014; 231:4611-21. [PMID: 24853690 DOI: 10.1007/s00213-014-3610-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 04/29/2014] [Indexed: 01/13/2023]
Abstract
RATIONALE The cAMP-dependent protein kinase A (PKA) signaling transduction pathway has been shown to play an important role in the modulation of several ethanol-induced behaviors. Different studies have demonstrated intracellular calcium (Ca(2+))-dependent activation of the PKA cascade after ethanol administration. Thus, the cAMP cascade mediator Ca(2+)-dependent calmodulin (CaM) has been strongly implicated in the central effects of ethanol. OBJECTIVES In this study, we assessed the role of the CaM inhibitor W7 on ethanol-induced stimulation, ethanol intake, and ethanol-induced activation of PKA. METHODS Swiss mice were pretreated with W7 (0-10 mg/kg) 30 min before ethanol (0-3.75 g/kg) administration. Immediately, animals were placed during 20 min in an open-field chamber. Ethanol (10 %, v/v) intake in 2 h was assessed using a limited access paradigm. Experiments with caffeine (0-15 mg/kg), cocaine (0-4 mg/kg), and saccharine (0.1 %, w/v) were designed to compare their results to those obtained with ethanol. Western blot was assayed 45 min after ethanol administration. RESULTS Results showed that pretreatment with W7, reduced selectively in a dose-dependent fashion ethanol-induced locomotor stimulation and ethanol intake. The ethanol-induced activation of PKA was also prevented by W7 administration. CONCLUSIONS These results demonstrate that CaM inhibition resulted in a selective reduction of ethanol-stimulating effects and ethanol intake. The PKA activation induced by ethanol was blocked after the CaM blockade with W7. These results provide further evidence of the key role of cellular Ca(2+)-dependent pathways on the central effects of ethanol.
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Affiliation(s)
- Pablo Baliño
- Área de Psicobiología, Universtitat Jaume I, Avda. Sos Baynat s/n, 12071, Castellón, Spain,
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12
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Robertson IM, Pineda-Sanabria SE, Holmes PC, Sykes BD. Conformation of the critical pH sensitive region of troponin depends upon a single residue in troponin I. Arch Biochem Biophys 2014; 552-553:40-9. [DOI: 10.1016/j.abb.2013.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 11/18/2013] [Accepted: 12/05/2013] [Indexed: 12/20/2022]
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13
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Li AY, Lee J, Borek D, Otwinowski Z, Tibbits GF, Paetzel M. Crystal structure of cardiac troponin C regulatory domain in complex with cadmium and deoxycholic acid reveals novel conformation. J Mol Biol 2011; 413:699-711. [PMID: 21920370 PMCID: PMC4068330 DOI: 10.1016/j.jmb.2011.08.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 08/23/2011] [Accepted: 08/24/2011] [Indexed: 01/07/2023]
Abstract
The amino-terminal regulatory domain of cardiac troponin C (cNTnC) plays an important role as the calcium sensor for the troponin complex. Calcium binding to cNTnC results in conformational changes that trigger a cascade of events that lead to cardiac muscle contraction. The cardiac N-terminal domain of TnC consists of two EF-hand calcium binding motifs, one of which is dysfunctional in binding calcium. Nevertheless, the defunct EF-hand still maintains a role in cNTnC function. For its structural analysis by X-ray crystallography, human cNTnC with the wild-type primary sequence was crystallized under a novel crystallization condition. The crystal structure was solved by the single-wavelength anomalous dispersion method and refined to 2.2 Å resolution. The structure displays several novel features. Firstly, both EF-hand motifs coordinate cadmium ions derived from the crystallization milieu. Secondly, the ion coordination in the defunct EF-hand motif accompanies unusual changes in the protein conformation. Thirdly, deoxycholic acid, also derived from the crystallization milieu, is bound in the central hydrophobic cavity. This is reminiscent of the interactions observed for cardiac calcium sensitizer drugs that bind to the same core region and maintain the "open" conformational state of calcium-bound cNTnC. The cadmium ion coordination in the defunct EF-hand indicates that this vestigial calcium binding site retains the structural and functional elements that allow it to coordinate a cadmium ion. However, it is a result of, or concomitant with, large and unusual structural changes in cNTnC.
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Affiliation(s)
- Alison Yueh Li
- Department of Molecular Biology and Biochemistry, Simon Fraser University, South Science Building, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6
- Department of Biomedical Physiology and Kinesiology, Molecular Cardiac Physiology Group, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6
| | - Jaeyong Lee
- Department of Molecular Biology and Biochemistry, Simon Fraser University, South Science Building, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6
| | - Dominika Borek
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Zbyszek Otwinowski
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Glen F. Tibbits
- Department of Molecular Biology and Biochemistry, Simon Fraser University, South Science Building, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6
- Department of Biomedical Physiology and Kinesiology, Molecular Cardiac Physiology Group, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6
- Cardiovascular Sciences, Child and Family Research Institute, 950 West 28 Ave, Vancouver, BC, Canada V5Z 4H4
| | - Mark Paetzel
- Department of Molecular Biology and Biochemistry, Simon Fraser University, South Science Building, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6
- Department of Biomedical Physiology and Kinesiology, Molecular Cardiac Physiology Group, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6
- Address correspondence to: Dr. Mark Paetzel, Simon Fraser University, Department of Molecular Biology and Biochemistry, South Science Building, 8888 University Drive, Burnaby, British Columbia, Canada V5A 1S6, Tel.: 778-782-4230, Fax.: 778-782-5583,
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14
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Robertson IM, Boyko RF, Sykes BD. Visualizing the principal component of ¹H, ¹⁵N-HSQC NMR spectral changes that reflect protein structural or functional properties: application to troponin C. JOURNAL OF BIOMOLECULAR NMR 2011; 51:115-122. [PMID: 21947920 DOI: 10.1007/s10858-011-9546-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 07/13/2011] [Indexed: 05/31/2023]
Abstract
Laboratories often repeatedly determine the structure of a given protein under a variety of conditions, mutations, modifications, or in a number of states. This approach can be cumbersome and tedious. Given then a database of structures, identifiers, and corresponding (1)H,(15)N-HSQC NMR spectra for homologous proteins, we investigated whether structural information could be ascertained for a new homolog solely from its (1)H,(15)N-HSQC NMR spectrum. We addressed this question with two different approaches. First, we used a semi-automated approach with the program, ORBplus. ORBplus looks for patterns in the chemical shifts and correlates these commonalities to the explicit property of interest. ORBplus ranks resonances based on consistency of the magnitude and direction of the chemical shifts within the database, and the chemical shift correlation of the unknown protein with the database. ORBplus visualizes the results by a histogram and a vector diagram, and provides residue specific predictions on structural similarities with the database. The second method we used was partial least squares (PLS), which is a multivariate statistical technique used to correlate response and predictor variables. We investigated the ability of these methods to predict the tertiary structure of the contractile regulatory protein troponin C. Troponin C undergoes a closed-to-open conformational change, which is coupled to its function in muscle. We found that both ORBplus and PLS were able to identify patterns in the (1)H,(15)N-HSQC NMR data from different states of troponin C that correlated to its conformation.
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Affiliation(s)
- Ian M Robertson
- Department of Biochemistry, University of Alberta, Edmonton, AB T5K 2W7, Canada
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15
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Pineda-Sanabria SE, Robertson IM, Sykes BD. Structure of trans-resveratrol in complex with the cardiac regulatory protein troponin C. Biochemistry 2011; 50:1309-20. [PMID: 21226534 DOI: 10.1021/bi101985j] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cardiac troponin, a heterotrimeric protein complex that regulates heart contraction, represents an attractive target for the development of drugs for treating heart disease. Cardiovascular diseases are one of the chief causes of morbidity and mortality worldwide. In France, however, the death rate from heart disease is remarkably low relative to fat consumption. This so-called "French paradox" has been attributed to the high level of consumption of wine in France, and the antioxidant trans-resveratrol is thought to be the primary basis for wine's cardioprotective nature. It has been demonstrated that trans-resveratrol increases the myofilament Ca(2+) sensitivity of guinea pig myocytes [Liew, R., Stagg, M. A., MacLeod, K. T., and Collins, P. (2005) Eur. J. Pharmacol. 519, 1-8]; however, the specific mode of its action is unknown. In this study, the structure of trans-resveratrol free and bound to the calcium-binding protein, troponin C, was determined by nuclear magnetic resonance spectroscopy. The results indicate that trans-resveratrol undergoes a minor conformational change upon binding to the hydrophobic pocket of the C-domain of troponin C. The location occupied by trans-resveratrol coincides with the binding site of troponin I, troponin C's natural binding partner. This has been seen for other troponin C-targeting inotropes and implicates the modulation of the troponin C-troponin I interaction as a possible mechanism of action for trans-resveratrol.
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Affiliation(s)
- Sandra E Pineda-Sanabria
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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16
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Robertson IM, Sun YB, Li MX, Sykes BD. A structural and functional perspective into the mechanism of Ca2+-sensitizers that target the cardiac troponin complex. J Mol Cell Cardiol 2010; 49:1031-41. [PMID: 20801130 DOI: 10.1016/j.yjmcc.2010.08.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 08/17/2010] [Accepted: 08/19/2010] [Indexed: 11/25/2022]
Abstract
The Ca(2+) dependent interaction between troponin I (cTnI) and troponin C (cTnC) triggers contraction in heart muscle. Heart failure is characterized by a decrease in cardiac output, and compounds that increase the sensitivity of cardiac muscle to Ca(2+) have therapeutic potential. The Ca(2+)-sensitizer, levosimendan, targets cTnC; however, detailed understanding of its mechanism has been obscured by its instability. In order to understand how this class of positive inotropes function, we investigated the mode of action of two fluorine containing novel analogs of levosimendan; 2',4'-difluoro(1,1'-biphenyl)-4-yloxy acetic acid (dfbp-o) and 2',4'-difluoro(1,1'-biphenyl)-4-yl acetic acid (dfbp). The affinities of dfbp and dfbp-o for the regulatory domain of cTnC were measured in the absence and presence of cTnI by NMR spectroscopy, and dfbp-o was found to bind more strongly than dfbp. Dfbp-o also increased the affinity of cTnI for cTnC. Dfbp-o increased the Ca(2+)-sensitivity of demembranated cardiac trabeculae in a manner similar to levosimendan. The high resolution NMR solution structure of the cTnC-cTnI-dfbp-o ternary complex showed that dfbp-o bound at the hydrophobic interface formed by cTnC and cTnI making critical interactions with residues such as Arg147 of cTnI. In the absence of cTnI, docking localized dfbp-o to the same position in the hydrophobic groove of cTnC. The structural and functional data reveal that the levosimendan class of Ca(2+)-sensitizers work by binding to the regulatory domain of cTnC and stabilizing the pivotal cTnC-cTnI regulatory unit via a network of hydrophobic and electrostatic interactions, in contrast to the destabilizing effects of antagonists such as W7 at the same interface.
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Affiliation(s)
- Ian M Robertson
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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17
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Oleszczuk M, Robertson IM, Li MX, Sykes BD. Solution structure of the regulatory domain of human cardiac troponin C in complex with the switch region of cardiac troponin I and W7: the basis of W7 as an inhibitor of cardiac muscle contraction. J Mol Cell Cardiol 2010; 48:925-33. [PMID: 20116385 DOI: 10.1016/j.yjmcc.2010.01.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 01/19/2010] [Accepted: 01/20/2010] [Indexed: 10/19/2022]
Abstract
The solution structure of Ca(2+)-bound regulatory domain of cardiac troponin C (cNTnC) in complex with the switch region of troponin I (cTnI(147-163)) and the calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfinamide (W7), has been determined by NMR spectroscopy. The structure reveals that the W7 naphthalene ring interacts with the terminal methyl groups of M47, M60, and M81 as well as aliphatic and aromatic side chains of several other residues in the hydrophobic pocket of cNTnC. The H3 ring proton of W7 also contacts the methyl groups of I148 and M153 of cTnI(147-163). The N-(6-aminohexyl) tail interacts primarily with the methyl groups of V64 and M81, which are located on the C- and D-helices of cNTnC. Compared to the structure of the cNTnC*Ca(2+)*W7 complex (Hoffman, R. M. B. and Sykes, B. D. (2009) Biochemistry 48, 5541-5552), the tail of W7 reorients slightly toward the surface of cNTnC while the ring remains in the hydrophobic pocket. The positively charged -NH(3)(+) group from the tail of W7 repels the positively charged R147 of cTnI(147-163). As a result, the N-terminus of the peptide moves away from cNTnC and the helical content of cTnI(147-163) is diminished, when compared to the structure of cNTnC*Ca(2+)*cTnI(147-163) (Li, M. X., Spyracopoulos, L., and Sykes B. D. (1999) Biochemistry 38, 8289-8298). Thus the ternary structure cNTnC*Ca(2+)*W7*cTnI(147-163) reported in this study offers an explanation for the approximately 13-fold affinity reduction of cTnI(147-163) for cNTnC*Ca(2+) in the presence of W7 and provides a structural basis for the inhibitory effect of W7 in cardiac muscle contraction. This generates molecular insight into structural features that are useful for the design of cTnC-specific Ca(2+)-desensitizing drugs.
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Affiliation(s)
- Marta Oleszczuk
- Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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