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Hock MT, Teitgen AE, McCabe KJ, Hirakis SP, Huber GA, Regnier M, Amaro RE, McCammon JA, McCulloch AD. Multiscale computational modeling of the effects of 2'-deoxy-ATP on cardiac muscle calcium handling. JOURNAL OF APPLIED PHYSICS 2023; 134:074905. [PMID: 37601331 PMCID: PMC10435275 DOI: 10.1063/5.0157935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/27/2023] [Indexed: 08/22/2023]
Abstract
2'-Deoxy-ATP (dATP), a naturally occurring near analog of ATP, is a well-documented myosin activator that has been shown to increase contractile force, improve pump function, and enhance lusitropy in the heart. Calcium transients in cardiomyocytes with elevated levels of dATP show faster calcium decay compared with cardiomyocytes with basal levels of dATP, but the mechanisms behind this are unknown. Here, we design and utilize a multiscale computational modeling framework to test the hypothesis that dATP acts on the sarcoendoplasmic reticulum calcium-ATPase (SERCA) pump to accelerate calcium re-uptake into the sarcoplasmic reticulum during cardiac relaxation. Gaussian accelerated molecular dynamics simulations of human cardiac SERCA2A in the E1 apo, ATP-bound and dATP-bound states showed that dATP forms more stable contacts in the nucleotide binding pocket of SERCA and leads to increased closure of cytosolic domains. These structural changes ultimately lead to changes in calcium binding, which we assessed using Brownian dynamics simulations. We found that dATP increases calcium association rate constants to SERCA and that dATP binds to apo SERCA more rapidly than ATP. Using a compartmental ordinary differential equation model of human cardiomyocyte excitation-contraction coupling, we found that these increased association rate constants contributed to the accelerated rates of calcium transient decay observed experimentally. This study provides clear mechanistic evidence of enhancements in cardiac SERCA2A pump function due to interactions with dATP.
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Affiliation(s)
- Marcus T. Hock
- Department of Bioengineering, University of California San Diego, La Jolla, California 92093, USA
| | - Abigail E. Teitgen
- Department of Bioengineering, University of California San Diego, La Jolla, California 92093, USA
| | - Kimberly J. McCabe
- Department of Computational Physiology, Simula Resesarch Laboratory, Oslo 0164, Norway
| | - Sophia P. Hirakis
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Gary A. Huber
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington 98109, USA
| | - Rommie E. Amaro
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
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2
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Mhatre KN, Mathieu J, Martinson A, Flint G, Blakley LP, Tabesh A, Reinecke H, Yang X, Guan X, Murali E, Klaiman JM, Odom GL, Brown MB, Tian R, Hauschka SD, Raftery D, Moussavi-Harami F, Regnier M, Murry CE. Cell based dATP delivery as a therapy for chronic heart failure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.24.538108. [PMID: 37162854 PMCID: PMC10168250 DOI: 10.1101/2023.04.24.538108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Transplanted human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) improve ventricular performance when delivered acutely post-myocardial infarction but are ineffective in chronic myocardial infarction/heart failure. 2'-deoxy-ATP (dATP) activates cardiac myosin and potently increases contractility. Here we engineered hPSC-CMs to overexpress ribonucleotide reductase, the enzyme controlling dATP production. In vivo, dATP-producing CMs formed new myocardium that transferred dATP to host cardiomyocytes via gap junctions, increasing their dATP levels. Strikingly, when transplanted into chronically infarcted hearts, dATP-producing grafts increased left ventricular function, whereas heart failure worsened with wild-type grafts or vehicle injections. dATP-donor cells recipients had greater voluntary exercise, improved cardiac metabolism, reduced pulmonary congestion and pathological cardiac hypertrophy, and improved survival. This combination of remuscularization plus enhanced host contractility offers a novel approach to treating the chronically failing heart.
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Affiliation(s)
- Ketaki N Mhatre
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Department of Bioengineering, University of Washington; Seattle, WA 98195, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
| | - Julie Mathieu
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Department of Comparative Medicine, University of Washington; Seattle, WA 98195, USA
| | - Amy Martinson
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
| | - Galina Flint
- Department of Bioengineering, University of Washington; Seattle, WA 98195, USA
- Center for Translational Muscle Research, University of Washington; Seattle, WA 98109, USA
| | - Leslie P Blakley
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
| | - Arash Tabesh
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
| | - Hans Reinecke
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
| | - Xiulan Yang
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
| | - Xuan Guan
- Department of Bioengineering, University of Washington; Seattle, WA 98195, USA
| | - Eesha Murali
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Department of Bioengineering, University of Washington; Seattle, WA 98195, USA
| | - Jordan M Klaiman
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
| | - Guy L Odom
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Center for Translational Muscle Research, University of Washington; Seattle, WA 98109, USA
- Department of Neurology, University of Washington; Seattle, WA 98195, USA
| | - Mary Beth Brown
- Center for Translational Muscle Research, University of Washington; Seattle, WA 98109, USA
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Washington; Seattle, WA 98195, USA
| | - Rong Tian
- Center for Translational Muscle Research, University of Washington; Seattle, WA 98109, USA
- Department of Anesthesiology and Pain Medicine, University of Washington; Seattle, WA 98195, USA
- The Mitochondria and Metabolism Center (MMC), University of Washington; Seattle, WA 98109, USA
| | - Stephen D Hauschka
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Center for Translational Muscle Research, University of Washington; Seattle, WA 98109, USA
- Department of Biochemistry, University of Washington; Seattle, WA 98195, USA
| | - Daniel Raftery
- Department of Anesthesiology and Pain Medicine, University of Washington; Seattle, WA 98195, USA
- The Mitochondria and Metabolism Center (MMC), University of Washington; Seattle, WA 98109, USA
- Northwest Metabolomics Research Center, University of Washington; Seattle, WA 98109, USA
| | - Farid Moussavi-Harami
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
- Center for Translational Muscle Research, University of Washington; Seattle, WA 98109, USA
- Division of Cardiology, University of Washington; Seattle, WA 98195, USA
| | - Michael Regnier
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Department of Bioengineering, University of Washington; Seattle, WA 98195, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Center for Translational Muscle Research, University of Washington; Seattle, WA 98109, USA
- Department of Physiology and Biophysics, University of Washington; Seattle, WA 98195, USA
| | - Charles E Murry
- Institute for Stem Cell and Regenerative Medicine, University of Washington; Seattle, WA 98109, USA
- Department of Bioengineering, University of Washington; Seattle, WA 98195, USA
- Center for Cardiovascular Biology, University of Washington; Seattle, WA 98109, USA
- Department of Laboratory Medicine & Pathology, University of Washington; Seattle, WA 98195, USA
- Center for Translational Muscle Research, University of Washington; Seattle, WA 98109, USA
- Division of Cardiology, University of Washington; Seattle, WA 98195, USA
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3
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Mhatre KN, Murray JD, Flint G, McMillen TS, Weber G, Shakeri M, Tu AY, Steczina S, Weiss R, Marcinek DJ, Murry CE, Raftery D, Tian R, Moussavi-Harami F, Regnier M. dATP elevation induces myocardial metabolic remodeling to support improved cardiac function. J Mol Cell Cardiol 2023; 175:1-12. [PMID: 36470336 PMCID: PMC9974746 DOI: 10.1016/j.yjmcc.2022.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/16/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Hallmark features of systolic heart failure are reduced contractility and impaired metabolic flexibility of the myocardium. Cardiomyocytes (CMs) with elevated deoxy ATP (dATP) via overexpression of ribonucleotide reductase (RNR) enzyme robustly improve contractility. However, the effect of dATP elevation on cardiac metabolism is unknown. Here, we developed proteolysis-resistant versions of RNR and demonstrate that elevation of dATP/ATP to ∼1% in CMs in a transgenic mouse (TgRRB) resulted in robust improvement of cardiac function. Pharmacological approaches showed that CMs with elevated dATP have greater basal respiratory rates by shifting myosin states to more active forms, independent of its isoform, in relaxed CMs. Targeted metabolomic profiling revealed a significant reprogramming towards oxidative phosphorylation in TgRRB-CMs. Higher cristae density and activity in the mitochondria of TgRRB-CMs improved respiratory capacity. Our results revealed a critical property of dATP to modulate myosin states to enhance contractility and induce metabolic flexibility to support improved function in CMs.
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Affiliation(s)
- Ketaki N Mhatre
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Jason D Murray
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Department of Physiology and Biophysics, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Galina Flint
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Timothy S McMillen
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA
| | - Gerhard Weber
- Division of Cardiology, University of Washington, Seattle, WA 98109, USA
| | - Majid Shakeri
- Division of Cardiology, University of Washington, Seattle, WA 98109, USA
| | - An-Yue Tu
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Sonette Steczina
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Robert Weiss
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
| | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, WA, USA
| | - Charles E Murry
- Division of Cardiology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Daniel Raftery
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109, USA; The Mitochondria and Metabolism Center (MMC), University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA
| | - Rong Tian
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109, USA; The Mitochondria and Metabolism Center (MMC), University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA
| | - Farid Moussavi-Harami
- Division of Cardiology, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA.
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Department of Physiology and Biophysics, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA.
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4
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Barrick SK, Greenberg MJ. Cardiac myosin contraction and mechanotransduction in health and disease. J Biol Chem 2021; 297:101297. [PMID: 34634306 PMCID: PMC8559575 DOI: 10.1016/j.jbc.2021.101297] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/17/2022] Open
Abstract
Cardiac myosin is the molecular motor that powers heart contraction by converting chemical energy from ATP hydrolysis into mechanical force. The power output of the heart is tightly regulated to meet the physiological needs of the body. Recent multiscale studies spanning from molecules to tissues have revealed complex regulatory mechanisms that fine-tune cardiac contraction, in which myosin not only generates power output but also plays an active role in its regulation. Thus, myosin is both shaped by and actively involved in shaping its mechanical environment. Moreover, these studies have shown that cardiac myosin-generated tension affects physiological processes beyond muscle contraction. Here, we review these novel regulatory mechanisms, as well as the roles that myosin-based force generation and mechanotransduction play in development and disease. We describe how key intra- and intermolecular interactions contribute to the regulation of myosin-based contractility and the role of mechanical forces in tuning myosin function. We also discuss the emergence of cardiac myosin as a drug target for diseases including heart failure, leading to the discovery of therapeutics that directly tune myosin contractility. Finally, we highlight some of the outstanding questions that must be addressed to better understand myosin's functions and regulation, and we discuss prospects for translating these discoveries into precision medicine therapeutics targeting contractility and mechanotransduction.
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Affiliation(s)
- Samantha K Barrick
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael J Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA.
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5
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Prakoso D, Tate M, Blasio M, Ritchie R. Adeno-associated viral (AAV) vector-mediated therapeutics for diabetic cardiomyopathy - current and future perspectives. Clin Sci (Lond) 2021; 135:1369-1387. [PMID: 34076247 PMCID: PMC8187922 DOI: 10.1042/cs20210052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 02/06/2023]
Abstract
Diabetes increases the prevalence of heart failure by 6-8-fold, independent of other comorbidities such as hypertension and coronary artery disease, a phenomenon termed diabetic cardiomyopathy. Several key signalling pathways have been identified that drive the pathological changes associated with diabetes-induced heart failure. This has led to the development of multiple pharmacological agents that are currently available for clinical use. While fairly effective at delaying disease progression, these treatments do not reverse the cardiac damage associated with diabetes. One potential alternative avenue for targeting diabetes-induced heart failure is the use of adeno-associated viral vector (AAV) gene therapy, which has shown great versatility in a multitude of disease settings. AAV gene therapy has the potential to target specific cells or tissues, has a low host immune response and has the possibility to represent a lifelong cure, not possible with current conventional pharmacotherapies. In this review, we will assess the therapeutic potential of AAV gene therapy as a treatment for diabetic cardiomyopathy.
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Affiliation(s)
- Darnel Prakoso
- Departments of Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Parkville Campus, Australia
| | - Mitchel Tate
- Departments of Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Parkville Campus, Australia
- Diabetes, Monash University, Clayton, Victoria 3800, Australia
| | - Miles J. De Blasio
- Departments of Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Parkville Campus, Australia
- Pharmacology, Monash University, Clayton, Victoria 3800, Australia
| | - Rebecca H. Ritchie
- Departments of Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Parkville Campus, Australia
- Diabetes, Monash University, Clayton, Victoria 3800, Australia
- Pharmacology, Monash University, Clayton, Victoria 3800, Australia
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6
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Carraro U, Yablonka-Reuveni Z. Translational research on Myology and Mobility Medicine: 2021 semi-virtual PDM3 from Thermae of Euganean Hills, May 26 - 29, 2021. Eur J Transl Myol 2021; 31:9743. [PMID: 33733717 PMCID: PMC8056169 DOI: 10.4081/ejtm.2021.9743] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/17/2021] [Indexed: 02/08/2023] Open
Abstract
On 19-21 November 2020, the meeting of the 30 years of the Padova Muscle Days was virtually held while the SARS-CoV-2 epidemic was hitting the world after a seemingly quiet summer. During the 2020-2021 winter, the epidemic is still active, despite the start of vaccinations. The organizers hope to hold the 2021 Padua Days on Myology and Mobility Medicine in a semi-virtual form (2021 S-V PDM3) from May 26 to May 29 at the Thermae of Euganean Hills, Padova, Italy. Here the program and the Collection of Abstracts are presented. Despite numerous world problems, the number of submitted/selected presentations (lectures and oral presentations) has increased, prompting the organizers to extend the program to four dense days.
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Affiliation(s)
- Ugo Carraro
- Department of Biomedical Sciences of the University of Padova, Italy; CIR-Myo - Myology Centre, University of Padova, Italy; A-C Mioni-Carraro Foundation for Translational Myology, Padova.
| | - Zipora Yablonka-Reuveni
- Department of Biological Structure, University of Washington School of Medicine, Seattle, WA.
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7
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Modulation of post-powerstroke dynamics in myosin II by 2'-deoxy-ADP. Arch Biochem Biophys 2020; 699:108733. [PMID: 33388313 DOI: 10.1016/j.abb.2020.108733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/25/2020] [Accepted: 12/18/2020] [Indexed: 01/10/2023]
Abstract
Muscle myosins are molecular motors that hydrolyze ATP and generate force through coordinated interactions with actin filaments, known as cross-bridge cycling. During the cross-bridge cycle, functional sites in myosin 'sense' changes in interactions with actin filaments and the nucleotide binding region, resulting in allosteric transmission of information throughout the structure. We investigated whether the dynamics of the post-powerstroke state of the cross-bridge cycle are modulated in a nucleotide-dependent fashion. We compared molecular dynamics simulations of the myosin II motor domain (M) from Dictyostelium discoideum in the presence of ADP (M.ADP) versus 2'-deoxy-ADP bound myosin (M.dADP). We found that dADP was more flexible than ADP and the two nucleotides interacted with myosin in different ways. Replacement of ADP with dADP in the post-powerstroke state also altered the conformation of the actin binding region in myosin heads. Our results provide atomic level insights into allosteric communication networks in myosin that provide insight into the nucleotide-dependent dynamics of the cross-bridge cycle.
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8
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Powers JD, Kooiker KB, Mason AB, Teitgen AE, Flint GV, Tardiff JC, Schwartz SD, McCulloch AD, Regnier M, Davis J, Moussavi-Harami F. Modulating the tension-time integral of the cardiac twitch prevents dilated cardiomyopathy in murine hearts. JCI Insight 2020; 5:142446. [PMID: 32931484 PMCID: PMC7605524 DOI: 10.1172/jci.insight.142446] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/09/2020] [Indexed: 12/13/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is often associated with sarcomere protein mutations that confer reduced myofilament tension–generating capacity. We demonstrated that cardiac twitch tension-time integrals can be targeted and tuned to prevent DCM remodeling in hearts with contractile dysfunction. We employed a transgenic murine model of DCM caused by the D230N-tropomyosin (Tm) mutation and designed a sarcomere-based intervention specifically targeting the twitch tension-time integral of D230N-Tm hearts using multiscale computational models of intramolecular and intermolecular interactions in the thin filament and cell-level contractile simulations. Our models predicted that increasing the calcium sensitivity of thin filament activation using the cardiac troponin C (cTnC) variant L48Q can sufficiently augment twitch tension-time integrals of D230N-Tm hearts. Indeed, cardiac muscle isolated from double-transgenic hearts expressing D230N-Tm and L48Q cTnC had increased calcium sensitivity of tension development and increased twitch tension-time integrals compared with preparations from hearts with D230N-Tm alone. Longitudinal echocardiographic measurements revealed that DTG hearts retained normal cardiac morphology and function, whereas D230N-Tm hearts developed progressive DCM. We present a computational and experimental framework for targeting molecular mechanisms governing the twitch tension of cardiomyopathic hearts to counteract putative mechanical drivers of adverse remodeling and open possibilities for tension-based treatments of genetic cardiomyopathies. Tuning the molecular mechanisms that govern the twitch tension of cardiomyopathic hearts counteracts mechanical drivers of adverse remodeling.
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Affiliation(s)
- Joseph D Powers
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, Washington, USA.,Department of Bioengineering, Jacobs School of Engineering, University of California San Diego, La Jolla, California, USA
| | - Kristina B Kooiker
- Division of Cardiology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Allison B Mason
- Department of Chemistry and Biochemistry, College of Science, and
| | - Abigail E Teitgen
- Department of Bioengineering, Jacobs School of Engineering, University of California San Diego, La Jolla, California, USA
| | - Galina V Flint
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, Washington, USA
| | - Jil C Tardiff
- Department of Biomedical Engineering, College of Engineering, University of Arizona, Tucson, Arizona, USA
| | | | - Andrew D McCulloch
- Department of Bioengineering, Jacobs School of Engineering, University of California San Diego, La Jolla, California, USA.,Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Michael Regnier
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, Washington, USA
| | - Jennifer Davis
- Department of Bioengineering, College of Engineering and School of Medicine, University of Washington, Seattle, Washington, USA.,Department of Laboratory Medicine & Pathology, University of Washington, Seattle, Washington, USA
| | - Farid Moussavi-Harami
- Division of Cardiology, School of Medicine, University of Washington, Seattle, Washington, USA
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9
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McCabe KJ, Aboelkassem Y, Teitgen AE, Huber GA, McCammon JA, Regnier M, McCulloch AD. Predicting the effects of dATP on cardiac contraction using multiscale modeling of the sarcomere. Arch Biochem Biophys 2020; 695:108582. [PMID: 32956632 DOI: 10.1016/j.abb.2020.108582] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/30/2020] [Accepted: 09/04/2020] [Indexed: 11/26/2022]
Abstract
2'-deoxy-ATP (dATP) is a naturally occurring small molecule that has shown promise as a therapeutic because it significantly increases cardiac myocyte force development even at low dATP/ATP ratios. To investigate mechanisms by which dATP alters myosin crossbridge dynamics, we used Brownian dynamics simulations to calculate association rates between actin and ADP- or dADP-bound myosin. These rates were then directly incorporated in a mechanistic Monte Carlo Markov Chain model of cooperative sarcomere contraction. A unique combination of increased powerstroke and detachment rates was required to match experimental steady-state and kinetic data for dATP force production in rat cardiac myocytes when the myosin attachment rate in the model was constrained by the results of a Brownian dynamics simulation. Nearest-neighbor cooperativity was seen to contribute to, but not fully explain, the steep relationship between dATP/ATP ratio and steady-state force-development observed at lower dATP concentrations. Dynamic twitch simulations performed using measured calcium transients as inputs showed that the effects of dATP on the crossbridge alone were not sufficient to explain experimentally observed enhancement of relaxation kinetics by dATP treatment. Hence, dATP may also affect calcium handling even at low concentrations. By enabling the effects of dATP on sarcomere mechanics to be predicted, this multi-scale modeling framework may elucidate the molecular mechanisms by which dATP can have therapeutic effects on cardiac contractile dysfunction.
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Affiliation(s)
- Kimberly J McCabe
- Simula Research Laboratory, Department of Computational Physiology, PO Box 134, 1325, Lysaker, Norway.
| | - Yasser Aboelkassem
- San Diego State University, Department of Mechanical Engineering, 5500 Campanile Drive San Diego, CA, 92182, USA
| | - Abigail E Teitgen
- University of California San Diego, Department of Bioengineering, 9500 Gilman Drive MC 0412 La Jolla, CA, 92093, USA
| | - Gary A Huber
- University of California San Diego, Department of Chemistry & Biochemistry, 9500 Gilman Drive, MC 0303 La Jolla, CA, 92093, USA
| | - J Andrew McCammon
- University of California San Diego, Department of Chemistry & Biochemistry, 9500 Gilman Drive, MC 0303 La Jolla, CA, 92093, USA
| | - Michael Regnier
- University of Washington, Department of Bioengineering, Box 355061 Seattle, WA, 98195, USA
| | - Andrew D McCulloch
- University of California San Diego, Department of Bioengineering, 9500 Gilman Drive MC 0412 La Jolla, CA, 92093, USA
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10
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Positional Isomers of a Non-Nucleoside Substrate Differentially Affect Myosin Function. Biophys J 2020; 119:567-580. [PMID: 32652059 DOI: 10.1016/j.bpj.2020.06.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 05/29/2020] [Accepted: 06/17/2020] [Indexed: 11/22/2022] Open
Abstract
Molecular motors have evolved to transduce chemical energy from ATP into mechanical work to drive essential cellular processes, from muscle contraction to vesicular transport. Dysfunction of these motors is a root cause of many pathologies necessitating the need for intrinsic control over molecular motor function. Herein, we demonstrate that positional isomerism can be used as a simple and powerful tool to control the molecular motor of muscle, myosin. Using three isomers of a synthetic non-nucleoside triphosphate, we demonstrate that myosin's force- and motion-generating capacity can be dramatically altered at both the ensemble and single-molecule levels. By correlating our experimental results with computation, we show that each isomer exerts intrinsic control by affecting distinct steps in myosin's mechanochemical cycle. Our studies demonstrate that subtle variations in the structure of an abiotic energy source can be used to control the force and motility of myosin without altering myosin's structure.
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11
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Kolwicz SC, Hall JK, Moussavi-Harami F, Chen X, Hauschka SD, Chamberlain JS, Regnier M, Odom GL. Gene Therapy Rescues Cardiac Dysfunction in Duchenne Muscular Dystrophy Mice by Elevating Cardiomyocyte Deoxy-Adenosine Triphosphate. JACC Basic Transl Sci 2019; 4:778-791. [PMID: 31998848 PMCID: PMC6978556 DOI: 10.1016/j.jacbts.2019.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/20/2019] [Accepted: 06/20/2019] [Indexed: 01/13/2023]
Abstract
Mutations in the gene encoding for dystrophin leads to structural and functional deterioration of cardiomyocytes and is a hallmark of cardiomyopathy in Duchenne muscular dystrophy (DMD) patients. Administration of recombinant adeno-associated viral vectors delivering microdystrophin or ribonucleotide reductase (RNR), under muscle-specific regulatory control, rescues both baseline and high workload-challenged hearts in an aged, DMD mouse model. However, only RNR treatments improved both systolic and diastolic function under those conditions. Cardiac-specific recombinant adeno-associated viral treatment of RNR holds therapeutic promise for improvement of cardiomyopathy in DMD patients.
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Key Words
- CK8, miniaturized murine creatine kinase regulatory cassette
- CMV, cytomegalovirus
- DMD, Duchenne muscular dystrophy
- RNR, ribonucleotide reductase
- cTnT, cardiac troponin T
- cardiomyopathy
- dADP, deoxy-adenosine diphosphate
- dATP, deoxy-adenosine triphosphate
- diastolic dysfunction
- dystrophin
- mdx, mouse muscular dystrophy model
- rAAV, recombinant adeno-associated viral vector
- recombinant adeno-associated virus vectors
- ribonucleotide reductase
- μDys, microdystrophin
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Affiliation(s)
- Stephen C. Kolwicz
- Mitochondria and Metabolism Center, University of Washington, Seattle, Washington
| | - John K. Hall
- Department of Neurology, University of Washington, Seattle, Washington
| | - Farid Moussavi-Harami
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington
| | - Xiolan Chen
- Department of Biochemistry, University of Washington, Seattle, Washington
- Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington
| | - Stephen D. Hauschka
- Department of Biochemistry, University of Washington, Seattle, Washington
- Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington
| | - Jeffrey S. Chamberlain
- Department of Neurology, University of Washington, Seattle, Washington
- Department of Biochemistry, University of Washington, Seattle, Washington
- Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington
| | - Michael Regnier
- Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington
- Department of Bioengineering, University of Washington, Seattle, Washington
- Center for Cardiovascular Biology, University of Washington, Seattle, Washington
| | - Guy L. Odom
- Department of Neurology, University of Washington, Seattle, Washington
- Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington
- Center for Cardiovascular Biology, University of Washington, Seattle, Washington
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12
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Powers JD, Yuan CC, McCabe KJ, Murray JD, Childers MC, Flint GV, Moussavi-Harami F, Mohran S, Castillo R, Zuzek C, Ma W, Daggett V, McCulloch AD, Irving TC, Regnier M. Cardiac myosin activation with 2-deoxy-ATP via increased electrostatic interactions with actin. Proc Natl Acad Sci U S A 2019; 116:11502-11507. [PMID: 31110001 PMCID: PMC6561254 DOI: 10.1073/pnas.1905028116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The naturally occurring nucleotide 2-deoxy-adenosine 5'-triphosphate (dATP) can be used by cardiac muscle as an alternative energy substrate for myosin chemomechanical activity. We and others have previously shown that dATP increases contractile force in normal hearts and models of depressed systolic function, but the structural basis of these effects has remained unresolved. In this work, we combine multiple techniques to provide structural and functional information at the angstrom-nanometer and millisecond time scales, demonstrating the ability to make both structural measurements and quantitative kinetic estimates of weak actin-myosin interactions that underpin sarcomere dynamics. Exploiting dATP as a molecular probe, we assess how small changes in myosin structure translate to electrostatic-based changes in sarcomere function to augment contractility in cardiac muscle. Through Brownian dynamics simulation and computational structural analysis, we found that deoxy-hydrolysis products [2-deoxy-adenosine 5'-diphosphate (dADP) and inorganic phosphate (Pi)] bound to prepowerstroke myosin induce an allosteric restructuring of the actin-binding surface on myosin to increase the rate of cross-bridge formation. We then show experimentally that this predicted effect translates into increased electrostatic interactions between actin and cardiac myosin in vitro. Finally, using small-angle X-ray diffraction analysis of sarcomere structure, we demonstrate that the proposed increased electrostatic affinity of myosin for actin causes a disruption of the resting conformation of myosin motors, resulting in their repositioning toward the thin filament before activation. The dATP-mediated structural alterations in myosin reported here may provide insight into an improved criterion for the design or selection of small molecules to be developed as therapeutic agents to treat systolic dysfunction.
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Affiliation(s)
- Joseph D Powers
- Department of Bioengineering, University of Washington, Seattle, WA 98109;
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Chen-Ching Yuan
- Department of Bioengineering, University of Washington, Seattle, WA 98109
| | - Kimberly J McCabe
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Jason D Murray
- Department of Bioengineering, University of Washington, Seattle, WA 98109
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98109
| | | | - Galina V Flint
- Department of Bioengineering, University of Washington, Seattle, WA 98109
| | - Farid Moussavi-Harami
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98109
| | - Saffie Mohran
- Department of Bioengineering, University of Washington, Seattle, WA 98109
| | - Romi Castillo
- Department of Bioengineering, University of Washington, Seattle, WA 98109
| | - Carla Zuzek
- Department of Bioengineering, University of Washington, Seattle, WA 98109
| | - Weikang Ma
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA 98109
| | - Andrew D McCulloch
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Thomas C Irving
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98109;
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98109
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13
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Tamargo J, Caballero R, Delpón E. New drugs in preclinical and early stage clinical development in the treatment of heart failure. Expert Opin Investig Drugs 2018; 28:51-71. [DOI: 10.1080/13543784.2019.1551357] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Juan Tamargo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense, CIBERCV, Madrid,
Spain
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense, CIBERCV, Madrid,
Spain
| | - Eva Delpón
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense, CIBERCV, Madrid,
Spain
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14
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Liu C, Kawana M, Song D, Ruppel KM, Spudich JA. Controlling load-dependent kinetics of β-cardiac myosin at the single-molecule level. Nat Struct Mol Biol 2018; 25:505-514. [PMID: 29867217 PMCID: PMC6092189 DOI: 10.1038/s41594-018-0069-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 04/26/2018] [Indexed: 01/29/2023]
Abstract
Concepts in molecular tension sensing in biology are growing and have their origins in studies of muscle contraction. In the heart muscle, a key parameter of contractility is the detachment rate of myosin from actin, which determines the time that myosin is bound to actin in a force-producing state and, importantly, depends on the load (force) against which myosin works. Here we measure the detachment rate of single molecules of human β-cardiac myosin and its load dependence. We find that both can be modulated by both small-molecule compounds and cardiomyopathy-causing mutations. Furthermore, effects of mutations can be reversed by introducing appropriate compounds. Our results suggest that activating versus inhibitory perturbations of cardiac myosin are discriminated by the aggregate result on duty ratio, average force, and ultimately average power output and suggest that cardiac contractility can be controlled by tuning the load-dependent kinetics of single myosin molecules.
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Affiliation(s)
- Chao Liu
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.
| | - Masataka Kawana
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Dan Song
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA, USA
| | - James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.
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15
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Teichman SL, Thomson KS, Regnier M. Cardiac Myosin Activation with Gene Therapy Produces Sustained Inotropic Effects and May Treat Heart Failure with Reduced Ejection Fraction. Handb Exp Pharmacol 2017; 243:447-464. [PMID: 27590227 DOI: 10.1007/164_2016_31] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic inotropic therapy is effective for the treatment of heart failure with reduced ejection fraction, but has been limited by adverse long-term safety profiles, development of tolerance, and the need for chronic parenteral administration. A safe and convenient therapeutic agent that produces sustained inotropic effects could improve symptoms, functional capacity, and quality of life. Small amounts of 2-deoxy-adenosine triphosphate (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin crossbridge cycling with greater force generation during each contraction. This paper describes the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy to deliver and upregulate ribonucleotide reductase (R1R2), the enzyme responsible for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with a benign safety profile. Further animal studies are appropriate with the goal of testing this agent in patients with heart failure.
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Affiliation(s)
- Sam L Teichman
- BEAT Biotherapeutics Corp, 1380 112th Ave., NE, Suite 200, Seattle, WA, 98004, USA.
| | | | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA, USA.,Center for Cardiovascular Biology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
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16
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Olafsson S, Whittington D, Murray J, Regnier M, Moussavi-Harami F. Fast and sensitive HPLC-MS/MS method for direct quantification of intracellular deoxyribonucleoside triphosphates from tissue and cells. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1068-1069:90-97. [PMID: 29032043 DOI: 10.1016/j.jchromb.2017.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/26/2017] [Accepted: 10/04/2017] [Indexed: 01/31/2023]
Abstract
Deoxyribonucleoside triphosphates (dNTPs) are used in DNA synthesis and repair. Even slight imbalances can have adverse biological effects. This study validates a fast and sensitive HPLC-MS/MS method for direct quantification of intracellular dNTPs from tissue. Equal volumes of methanol and water were used for nucleotide extraction from mouse heart and gastrocnemius muscle and isolated cardiomyocytes followed by centrifugation to remove particulates. The resulting supernatant was analyzed on a porous graphitic carbon chromatography column using an elution gradient of ammonium acetate in water and ammonium hydroxide in acetonitrile with a run time of just 10min. Calibration curves of all dNTPs ranged from 62.5 to 2500fmol injections and demonstrated excellent linearity (r2>0.99). The within day and between day precision, as measured by the coefficient of variation (CV (%)), was <25% for all points, including the lower limit of quantification (LLOQ). The inter-day accuracy was within 12% of expected concentration for the LLOQ and within 7% for all other points on the calibration curve. The intra-day accuracy was within 22% for the LLOQ and within 11% for all points on the curve. Compared to existing methods, this study presents a faster and more sensitive method for dNTP quantification.
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Affiliation(s)
- Sigurast Olafsson
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98109, United States
| | - Dale Whittington
- Department of Medicinal Chemistry, University of Washington, Box 357610 H172, Health Science Building, Seattle, WA 98195-7610, United States
| | - Jason Murray
- Department of Physiology and Biophysics, University of Washington, 1705 NE Pacific Street, HSB Room G424, Box 357290, Seattle, WA 98195-7290, United States
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Box 355061, Seattle, WA 98195-5061, United States
| | - Farid Moussavi-Harami
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98109, United States.
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17
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Regnier M, Moussavi-Harami F. Gene Therapy for Nonischemic Cardiomyopathy: Moving Forward by Learning From Lessons of the Past. J Am Coll Cardiol 2017; 70:1757-1759. [PMID: 28958333 DOI: 10.1016/j.jacc.2017.08.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 11/15/2022]
Affiliation(s)
- Michael Regnier
- Department of Bioengineering, Center for Cardiovascular Biology and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington.
| | - Farid Moussavi-Harami
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington
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18
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Ishida J, Saitoh M, Doehner W, von Haehling S, Anker M, Anker SD, Springer J. Animal models of cachexia and sarcopenia in chronic illness: Cardiac function, body composition changes and therapeutic results. Int J Cardiol 2017; 238:12-18. [DOI: 10.1016/j.ijcard.2017.03.154] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 03/31/2017] [Accepted: 03/31/2017] [Indexed: 02/07/2023]
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19
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Lopez D, Pan JA, Pollak PM, Clarke S, Kramer CM, Yeager M, Salerno M. Multiparametric CMR imaging of infarct remodeling in a percutaneous reperfused Yucatan mini-pig model. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3693. [PMID: 28164391 PMCID: PMC5488275 DOI: 10.1002/nbm.3693] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 12/02/2016] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
To further understanding of the temporal evolution and pathophysiology of adverse ventricular remodeling over the first 60 days following a myocardial infarction (MI) in both the infarcted and remote myocardium, we performed multi-parametric cardiac magnetic resonance (CMR) imaging in a closed-chest chronic Yucatan mini-pig model of reperfused MI. Ten animals underwent 90 min left anterior descending artery occlusion and reperfusion. Three animals served as controls. Multiparametric CMR (1.5T) was performed at baseline, Day 2, Day 30 and in four animals on Day 60 after MI. Left ventricular (LV) volumes and infarct size were measured. T1 and T2 mapping sequences were performed to measure values in the infarct and remote regions. Remote region collagen fractions were compared between infarcted animals and controls. Procedure success was 80%. The model created large infarcts (28 ± 5% of LV mass on Day 2), which led to significant adverse myocardial remodeling that stabilized beyond 30 days. Native T1 values did not reliably differentiate remote and infarct regions acutely. There was no evidence of remote fibrosis as indicated by partition coefficient and collagen fraction analyses. The infarct T2 values remained elevated up to 60 days after MI. Multiparametric CMR in this model showed significant adverse ventricular remodeling 30 days after MI similar to that seen in humans. In addition, this study demonstrated that remote fibrosis is absent and that infarct T2 signal remains chronically elevated in this model. These findings need to be considered when designing preclinical trials using CMR endpoints.
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Affiliation(s)
- David Lopez
- Departments of Medicine, University of Virginia Health System, Charlottesville, VA, USA
| | - Jonathan A. Pan
- Departments of Medicine, University of Virginia Health System, Charlottesville, VA, USA
- Biomedical Engineering, University of Virginia Health System, Charlottesville, VA, USA
| | - Peter M. Pollak
- Departments of Medicine, University of Virginia Health System, Charlottesville, VA, USA
| | - Samantha Clarke
- Biomedical Engineering, University of Virginia Health System, Charlottesville, VA, USA
| | - Christopher M. Kramer
- Departments of Medicine, University of Virginia Health System, Charlottesville, VA, USA
- Radiology & Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA
| | - Mark Yeager
- Departments of Medicine, University of Virginia Health System, Charlottesville, VA, USA
- Molecular Physiology & Biological Physics, University of Virginia Health System, Charlottesville, VA, USA
| | - Michael Salerno
- Departments of Medicine, University of Virginia Health System, Charlottesville, VA, USA
- Biomedical Engineering, University of Virginia Health System, Charlottesville, VA, USA
- Radiology & Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA
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20
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Nowakowski SG, Regnier M, Daggett V. Molecular mechanisms underlying deoxy-ADP.Pi activation of pre-powerstroke myosin. Protein Sci 2017; 26:749-762. [PMID: 28097776 DOI: 10.1002/pro.3121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 01/19/2023]
Abstract
Myosin activation is a viable approach to treat systolic heart failure. We previously demonstrated that striated muscle myosin is a promiscuous ATPase that can use most nucleoside triphosphates as energy substrates for contraction. When 2-deoxy ATP (dATP) is used, it acts as a myosin activator, enhancing cross-bridge binding and cycling. In vivo, we have demonstrated that elevated dATP levels increase basal cardiac function and rescues function of infarcted rodent and pig hearts. Here we investigate the molecular mechanism underlying this physiological effect. We show with molecular dynamics simulations that the binding of dADP.Pi (dATP hydrolysis products) to myosin alters the structure and dynamics of the nucleotide binding pocket, myosin cleft conformation, and actin binding sites, which collectively yield a myosin conformation that we predict favors weak, electrostatic binding to actin. In vitro motility assays at high ionic strength were conducted to test this prediction and we found that dATP increased motility. These results highlight alterations to myosin that enhance cross-bridge formation and reveal a potential mechanism that may underlie dATP-induced improvements in cardiac function.
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Affiliation(s)
- Sarah G Nowakowski
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195-5013
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195-5013.,Center for Cardiovascular Biology, University of Washington, Seattle, Washington, 98195-5013
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195-5013
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21
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Translation of Cardiac Myosin Activation with 2-deoxy-ATP to Treat Heart Failure via an Experimental Ribonucleotide Reductase-Based Gene Therapy. JACC Basic Transl Sci 2016; 1:666-679. [PMID: 28553667 PMCID: PMC5444879 DOI: 10.1016/j.jacbts.2016.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Despite recent advances, chronic heart failure remains a significant and growing unmet medical need, reaching epidemic proportions carrying substantial morbidity, mortality, and costs. A safe and convenient therapeutic agent that produces sustained inotropic effects could ameliorate symptoms and improve functional capacity and quality of life. The authors discovered that small amounts of 2-deoxy-ATP (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin cross-bridge cycling with greater force generation during each contraction. They describe the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy that up-regulates ribonucleotide reductase, the rate-limiting enzyme for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with no toxicity or safety concerns identified to date. Further animal studies are being conducted with the goal of testing this agent in patients with heart failure.
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22
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Cheng Y, Hogarth KA, O'Sullivan ML, Regnier M, Pyle WG. 2-Deoxyadenosine triphosphate restores the contractile function of cardiac myofibril from adult dogs with naturally occurring dilated cardiomyopathy. Am J Physiol Heart Circ Physiol 2016; 310:H80-91. [PMID: 26497964 PMCID: PMC4796460 DOI: 10.1152/ajpheart.00530.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/08/2015] [Indexed: 11/22/2022]
Abstract
Dilated cardiomyopathy (DCM) is a major type of heart failure resulting from loss of systolic function. Naturally occurring canine DCM is a widely accepted experimental paradigm for studying human DCM. 2-Deoxyadenosine triphosphate (dATP) can be used by myosin and is a superior energy substrate over ATP for cross-bridge formation and increased systolic function. The objective of this study was to evaluate the beneficial effect of dATP on contractile function of cardiac myofibrils from dogs with naturally occurring DCM. We measured actomyosin NTPase activity and contraction/relaxation properties of isolated myofibrils from nonfailing (NF) and DCM canine hearts. NTPase assays indicated replacement of ATP with dATP significantly increased myofilament activity in both NF and DCM samples. dATP significantly improved maximal tension of DCM myofibrils to the NF sample level. dATP also restored Ca(2+) sensitivity of tension that was reduced in DCM samples. Similarly, dATP increased the kinetics of contractile activation (kACT), with no impact on the rate of cross-bridge tension redevelopment (kTR). Thus, the activation kinetics (kACT/kTR) that were reduced in DCM samples were restored for dATP to NF sample levels. dATP had little effect on relaxation. The rate of early slow-phase relaxation was slightly reduced with dATP, but its duration was not, nor was the fast-phase relaxation or times to 50 and 90% relaxation. Our findings suggest that myosin utilization of dATP improves cardiac myofibril contractile properties of naturally occurring DCM canine samples, restoring them to NF levels, without compromising relaxation. This suggests elevation of cardiac dATP is a promising approach for the treatment of DCM.
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Affiliation(s)
- Yuanhua Cheng
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Kaley A Hogarth
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and
| | - M Lynne O'Sullivan
- Department of Clinical Studies, University of Guelph, Guelph, Ontario, Canada
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - W Glen Pyle
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and
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23
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Kolwicz SC, Odom GL, Nowakowski SG, Moussavi-Harami F, Chen X, Reinecke H, Hauschka SD, Murry CE, Mahairas GG, Regnier M. AAV6-mediated Cardiac-specific Overexpression of Ribonucleotide Reductase Enhances Myocardial Contractility. Mol Ther 2015; 24:240-250. [PMID: 26388461 DOI: 10.1038/mt.2015.176] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 09/10/2015] [Indexed: 12/13/2022] Open
Abstract
Impaired systolic function, resulting from acute injury or congenital defects, leads to cardiac complications and heart failure. Current therapies slow disease progression but do not rescue cardiac function. We previously reported that elevating the cellular 2 deoxy-ATP (dATP) pool in transgenic mice via increased expression of ribonucleotide reductase (RNR), the enzyme that catalyzes deoxy-nucleotide production, increases myosin-actin interaction and enhances cardiac muscle contractility. For the current studies, we initially injected wild-type mice retro-orbitally with a mixture of adeno-associated virus serotype-6 (rAAV6) containing a miniaturized cardiac-specific regulatory cassette (cTnT(455)) composed of enhancer and promotor portions of the human cardiac troponin T gene (TNNT2) ligated to rat cDNAs encoding either the Rrm1 or Rrm2 subunit. Subsequent studies optimized the system by creating a tandem human RRM1-RRM2 cDNA with a P2A self-cleaving peptide site between the subunits. Both rat and human Rrm1/Rrm2 cDNAs resulted in RNR enzyme overexpression exclusively in the heart and led to a significant elevation of left ventricular (LV) function in normal mice and infarcted rats, measured by echocardiography or isolated heart perfusions, without adverse cardiac remodeling. Our study suggests that increasing RNR levels via rAAV-mediated cardiac-specific expression provide a novel gene therapy approach to potentially enhance cardiac systolic function in animal models and patients with heart failure.
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Affiliation(s)
- Stephen C Kolwicz
- Mitochondria and Metabolism Center, University of Washington, Seattle, Washington, USA
| | - Guy L Odom
- Department of Neurology, University of Washington, Seattle, Washington, USA
| | - Sarah G Nowakowski
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Farid Moussavi-Harami
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Xiaolan Chen
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Hans Reinecke
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Stephen D Hauschka
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Charles E Murry
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, USA; Department of Pathology, University of Washington, Seattle, Washington, USA; Center for Cardiovascular Biology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA
| | | | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Center for Cardiovascular Biology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA.
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24
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Metra M. August 2015 at a glance. Eur J Heart Fail 2015. [DOI: 10.1002/ejhf.329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Marco Metra
- Cardiology, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health; University of Brescia; Brescia Italy
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25
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Psotka MA, Teerlink JR. Cardiac myosin activators: up and coming. Eur J Heart Fail 2015; 17:750-2. [PMID: 26179667 DOI: 10.1002/ejhf.313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/09/2015] [Indexed: 01/10/2023] Open
Affiliation(s)
- Mitchell A Psotka
- School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - John R Teerlink
- School of Medicine, University of California San Francisco, San Francisco, CA, USA.,Section of Cardiology, San Francisco Veterans Affairs Medical Center, San Francisco, CA, USA
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