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Wait SJ, Expòsit M, Lin S, Rappleye M, Lee JD, Colby SA, Torp L, Asencio A, Smith A, Regnier M, Moussavi-Harami F, Baker D, Kim CK, Berndt A. Machine learning-guided engineering of genetically encoded fluorescent calcium indicators. Nat Comput Sci 2024; 4:224-236. [PMID: 38532137 DOI: 10.1038/s43588-024-00611-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 02/15/2024] [Indexed: 03/28/2024]
Abstract
Here we used machine learning to engineer genetically encoded fluorescent indicators, protein-based sensors critical for real-time monitoring of biological activity. We used machine learning to predict the outcomes of sensor mutagenesis by analyzing established libraries that link sensor sequences to functions. Using the GCaMP calcium indicator as a scaffold, we developed an ensemble of three regression models trained on experimentally derived GCaMP mutation libraries. The trained ensemble performed an in silico functional screen on 1,423 novel, uncharacterized GCaMP variants. As a result, we identified the ensemble-derived GCaMP (eGCaMP) variants, eGCaMP and eGCaMP+, which achieve both faster kinetics and larger ∆F/F0 responses upon stimulation than previously published fast variants. Furthermore, we identified a combinatorial mutation with extraordinary dynamic range, eGCaMP2+, which outperforms the tested sixth-, seventh- and eighth-generation GCaMPs. These findings demonstrate the value of machine learning as a tool to facilitate the efficient engineering of proteins for desired biophysical characteristics.
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Affiliation(s)
- Sarah J Wait
- Molecular Engineering and Sciences Institute, University of Washington, Seattle, WA, USA
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Marc Expòsit
- Molecular Engineering and Sciences Institute, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Sophia Lin
- Center for Neuroscience, University of California, Davis, Davis, CA, USA
- Department of Neurology, University of California, Davis, Davis, CA, USA
| | - Michael Rappleye
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland
| | - Justin Daho Lee
- Molecular Engineering and Sciences Institute, University of Washington, Seattle, WA, USA
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Samuel A Colby
- Molecular Engineering and Sciences Institute, University of Washington, Seattle, WA, USA
| | - Lily Torp
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Anthony Asencio
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Annette Smith
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Michael Regnier
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Farid Moussavi-Harami
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - David Baker
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Christina K Kim
- Center for Neuroscience, University of California, Davis, Davis, CA, USA
- Department of Neurology, University of California, Davis, Davis, CA, USA
| | - Andre Berndt
- Molecular Engineering and Sciences Institute, University of Washington, Seattle, WA, USA.
- Institute of Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
- Center for Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA.
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Mohran S, Kooiker K, Mahoney-Schaefer M, Mandrycky C, Kao K, Tu AY, Freeman J, Moussavi-Harami F, Geeves M, Regnier M. The biochemically defined super relaxed state of myosin-A paradox. J Biol Chem 2024; 300:105565. [PMID: 38103642 PMCID: PMC10819765 DOI: 10.1016/j.jbc.2023.105565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/06/2023] [Accepted: 12/06/2023] [Indexed: 12/19/2023] Open
Abstract
The biochemical SRX (super-relaxed) state of myosin has been defined as a low ATPase activity state. This state can conserve energy when the myosin is not recruited for muscle contraction. The SRX state has been correlated with a structurally defined ordered (versus disordered) state of muscle thick filaments. The two states may be linked via a common interacting head motif (IHM) where the two heads of heavy meromyosin (HMM), or myosin, fold back onto each other and form additional contacts with S2 and the thick filament. Experimental observations of the SRX, IHM, and the ordered form of thick filaments, however, do not always agree, and result in a series of unresolved paradoxes. To address these paradoxes, we have reexamined the biochemical measurements of the SRX state for porcine cardiac HMM. In our hands, the commonly employed mantATP displacement assay was unable to quantify the population of the SRX state with all data fitting very well by a single exponential. We further show that mavacamten inhibits the basal ATPases of both porcine ventricle HMM and S1 (Ki, 0.32 and 1.76 μM respectively) while dATP activates HMM cooperatively without any evidence of an SRX state. A combination of our experimental observations and theories suggests that the displacement of mantATP in purified proteins is not a reliable assay to quantify the SRX population. This means that while the structurally defined IHM and ordered thick filaments clearly exist, great care must be employed when using the mantATP displacement assay.
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Affiliation(s)
- Saffie Mohran
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Center for Translational Muscle Research, University of Washington, Seattle, Washington, USA
| | - Kristina Kooiker
- Center for Translational Muscle Research, University of Washington, Seattle, Washington, USA; Division of Cardiology, University of Washington, Seattle, Washington, USA
| | | | - Christian Mandrycky
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Center for Translational Muscle Research, University of Washington, Seattle, Washington, USA
| | - Kerry Kao
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - An-Yue Tu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Center for Translational Muscle Research, University of Washington, Seattle, Washington, USA
| | - Jeremy Freeman
- Division of Cardiology, University of Washington, Seattle, Washington, USA
| | - Farid Moussavi-Harami
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Center for Translational Muscle Research, University of Washington, Seattle, Washington, USA; Division of Cardiology, University of Washington, Seattle, Washington, USA
| | - Michael Geeves
- School of Biosciences, University of Kent, Canterbury, UK.
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Center for Translational Muscle Research, University of Washington, Seattle, Washington, USA.
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Flint G, Kooiker K, Moussavi-Harami F. Echocardiography to Assess Cardiac Structure and Function in Genetic Cardiomyopathies. Methods Mol Biol 2024; 2735:1-15. [PMID: 38038840 DOI: 10.1007/978-1-0716-3527-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Rodents are the most common experimental models used in cardiovascular research including studies of genetic cardiomyopathies. Genetic cardiomyopathies are characterized by changes in cardiac structure and function. Echocardiography allows for relatively inexpensive, non-invasive, reliable, and reproducible assessment of these changes. However, the fast heart and small size present unique challenges for investigators. To ensure accuracy and reproducibility of these measurements, investigators need to be familiar with standard practices in the field, normal values, and potential pitfalls. The goal of this chapter is to describe steps needed for reliable acquisition and analysis of echocardiography in rodent models. Additionally, we discuss some common pitfalls and challenges.
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Affiliation(s)
- Galina Flint
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Translational Muscle Research, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Kristina Kooiker
- Center for Translational Muscle Research, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - Farid Moussavi-Harami
- Center for Translational Muscle Research, University of Washington, Seattle, WA, USA.
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.
- Division of Cardiology, University of Washington, Seattle, WA, USA.
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA.
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Kooiker KB, Mohran S, Turner KL, Ma W, Martinson A, Flint G, Qi L, Gao C, Zheng Y, McMillen TS, Mandrycky C, Mahoney-Schaefer M, Freeman JC, Costales Arenas EG, Tu AY, Irving TC, Geeves MA, Tanner BC, Regnier M, Davis J, Moussavi-Harami F. Danicamtiv Increases Myosin Recruitment and Alters Cross-Bridge Cycling in Cardiac Muscle. Circ Res 2023; 133:430-443. [PMID: 37470183 PMCID: PMC10434831 DOI: 10.1161/circresaha.123.322629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND Modulating myosin function is a novel therapeutic approach in patients with cardiomyopathy. Danicamtiv is a novel myosin activator with promising preclinical data that is currently in clinical trials. While it is known that danicamtiv increases force and cardiomyocyte contractility without affecting calcium levels, detailed mechanistic studies regarding its mode of action are lacking. METHODS Permeabilized porcine cardiac tissue and myofibrils were used for X-ray diffraction and mechanical measurements. A mouse model of genetic dilated cardiomyopathy was used to evaluate the ability of danicamtiv to correct the contractile deficit. RESULTS Danicamtiv increased force and calcium sensitivity via increasing the number of myosins in the ON state and slowing cross-bridge turnover. Our detailed analysis showed that inhibition of ADP release results in decreased cross-bridge turnover with cross bridges staying attached longer and prolonging myofibril relaxation. Danicamtiv corrected decreased calcium sensitivity in demembranated tissue, abnormal twitch magnitude and kinetics in intact cardiac tissue, and reduced ejection fraction in the whole organ. CONCLUSIONS As demonstrated by the detailed studies of Danicamtiv, increasing myosin recruitment and altering cross-bridge cycling are 2 mechanisms to increase force and calcium sensitivity in cardiac muscle. Myosin activators such as Danicamtiv can treat the causative hypocontractile phenotype in genetic dilated cardiomyopathy.
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Affiliation(s)
- Kristina B. Kooiker
- Division of Cardiology, Medicine (K.B.K., M.M.-S., J.C.F., E.G.C.A., F.M.-H.), University of Washington
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Center for Cardiovascular Biology (K.B.K., A.M., M.R., J.D., F.M.-H.), University of Washington
- Institute for Stem Cell & Regenerative Medicine (K.B.K., S.M., A.M., T.S.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
| | - Saffie Mohran
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Institute for Stem Cell & Regenerative Medicine (K.B.K., S.M., A.M., T.S.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Department of Bioengineering (S.M., A.M., G.F., C.M., A.-Y.T., M.R., J.D.), University of Washington
| | - Kyrah L. Turner
- School of Molecular Biosciences, Washington State University (K.L.T.)
| | - Weikang Ma
- Department of Biology, Illinois Institute of Technology, Chicago (W.M., L.Q., T.C.I.)
| | - Amy Martinson
- Center for Cardiovascular Biology (K.B.K., A.M., M.R., J.D., F.M.-H.), University of Washington
- Department of Laboratory Medicine and Pathology (A.M., J.D., F.M.-H.), University of Washington
- Institute for Stem Cell & Regenerative Medicine (K.B.K., S.M., A.M., T.S.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Department of Bioengineering (S.M., A.M., G.F., C.M., A.-Y.T., M.R., J.D.), University of Washington
| | - Galina Flint
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Department of Bioengineering (S.M., A.M., G.F., C.M., A.-Y.T., M.R., J.D.), University of Washington
| | - Lin Qi
- Department of Biology, Illinois Institute of Technology, Chicago (W.M., L.Q., T.C.I.)
| | - Chengqian Gao
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China (C.G., Y.Z.)
| | - Yahan Zheng
- College of Basic Medical Sciences, Dalian Medical University, Liaoning, China (C.G., Y.Z.)
| | - Timothy S. McMillen
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Institute for Stem Cell & Regenerative Medicine (K.B.K., S.M., A.M., T.S.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Department of Anesthesiology and Pain Medicine (T.S.M.), University of Washington
| | - Christian Mandrycky
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Department of Bioengineering (S.M., A.M., G.F., C.M., A.-Y.T., M.R., J.D.), University of Washington
| | - Max Mahoney-Schaefer
- Division of Cardiology, Medicine (K.B.K., M.M.-S., J.C.F., E.G.C.A., F.M.-H.), University of Washington
| | - Jeremy C. Freeman
- Division of Cardiology, Medicine (K.B.K., M.M.-S., J.C.F., E.G.C.A., F.M.-H.), University of Washington
| | | | - An-Yu Tu
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Institute for Stem Cell & Regenerative Medicine (K.B.K., S.M., A.M., T.S.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Department of Bioengineering (S.M., A.M., G.F., C.M., A.-Y.T., M.R., J.D.), University of Washington
| | - Thomas C. Irving
- Department of Biology, Illinois Institute of Technology, Chicago (W.M., L.Q., T.C.I.)
| | - Michael A. Geeves
- School of Biosciences, Division of Natural Sciences, University of Kent, Canterbury, United Kingdom (M.A.G.)
| | - Bertrand C.W. Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University (B.C.W.T.)
| | - Michael Regnier
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Center for Cardiovascular Biology (K.B.K., A.M., M.R., J.D., F.M.-H.), University of Washington
- Institute for Stem Cell & Regenerative Medicine (K.B.K., S.M., A.M., T.S.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Department of Bioengineering (S.M., A.M., G.F., C.M., A.-Y.T., M.R., J.D.), University of Washington
| | - Jennifer Davis
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Center for Cardiovascular Biology (K.B.K., A.M., M.R., J.D., F.M.-H.), University of Washington
- Department of Laboratory Medicine and Pathology (A.M., J.D., F.M.-H.), University of Washington
- Institute for Stem Cell & Regenerative Medicine (K.B.K., S.M., A.M., T.S.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Department of Bioengineering (S.M., A.M., G.F., C.M., A.-Y.T., M.R., J.D.), University of Washington
| | - Farid Moussavi-Harami
- Division of Cardiology, Medicine (K.B.K., M.M.-S., J.C.F., E.G.C.A., F.M.-H.), University of Washington
- Center of Translational Muscle Research (K.B.K., S.M., G.F., T.S.M., C.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
- Center for Cardiovascular Biology (K.B.K., A.M., M.R., J.D., F.M.-H.), University of Washington
- Department of Laboratory Medicine and Pathology (A.M., J.D., F.M.-H.), University of Washington
- Institute for Stem Cell & Regenerative Medicine (K.B.K., S.M., A.M., T.S.M., A.-Y.T., M.R., J.D., F.M.-H.), University of Washington
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Chakraborty AD, Kooiker K, Kobak KA, Cheng Y, Lee CF, Razumova M, Granzier H H, Regnier M, Rabinovitch PS, Moussavi-Harami F, Chiao YA. Late-life Rapamycin Treatment Enhances Cardiomyocyte Relaxation Kinetics and Reduces Myocardial Stiffness. bioRxiv 2023:2023.06.12.544619. [PMID: 37398078 PMCID: PMC10312630 DOI: 10.1101/2023.06.12.544619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Diastolic dysfunction is a key feature of the aging heart. We have shown that late-life treatment with mTOR inhibitor, rapamycin, reverses age-related diastolic dysfunction in mice but the molecular mechanisms of the reversal remain unclear. To dissect the mechanisms by which rapamycin improves diastolic function in old mice, we examined the effects of rapamycin treatment at the levels of single cardiomyocyte, myofibril and multicellular cardiac muscle. Compared to young cardiomyocytes, isolated cardiomyocytes from old control mice exhibited prolonged time to 90% relaxation (RT 90 ) and time to 90% Ca 2+ transient decay (DT 90 ), indicating slower relaxation kinetics and calcium reuptake with age. Late-life rapamycin treatment for 10 weeks completely normalized RT 90 and partially normalized DT 90 , suggesting improved Ca 2+ handling contributes partially to the rapamycin-induced improved cardiomyocyte relaxation. In addition, rapamycin treatment in old mice enhanced the kinetics of sarcomere shortening and Ca 2+ transient increase in old control cardiomyocytes. Myofibrils from old rapamycin-treated mice displayed increased rate of the fast, exponential decay phase of relaxation compared to old controls. The improved myofibrillar kinetics were accompanied by an increase in MyBP-C phosphorylation at S282 following rapamycin treatment. We also showed that late-life rapamycin treatment normalized the age-related increase in passive stiffness of demembranated cardiac trabeculae through a mechanism independent of titin isoform shift. In summary, our results showed that rapamycin treatment normalizes the age-related impairments in cardiomyocyte relaxation, which works conjointly with reduced myocardial stiffness to reverse age-related diastolic dysfunction.
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Asencio A, Malingen S, Kooiker KB, Powers JD, Davis J, Daniel T, Moussavi-Harami F. Machine learning meets Monte Carlo methods for models of muscle's molecular machinery to classify mutations. J Gen Physiol 2023; 155:e202213291. [PMID: 37000171 PMCID: PMC10067704 DOI: 10.1085/jgp.202213291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/14/2023] [Accepted: 03/14/2023] [Indexed: 04/01/2023] Open
Abstract
The timing and magnitude of force generation by a muscle depend on complex interactions in a compliant, contractile filament lattice. Perturbations in these interactions can result in cardiac muscle diseases. In this study, we address the fundamental challenge of connecting the temporal features of cardiac twitches to underlying rate constants and their perturbations associated with genetic cardiomyopathies. Current state-of-the-art metrics for characterizing the mechanical consequence of cardiac muscle disease do not utilize information embedded in the complete time course of twitch force. We pair dimension reduction techniques and machine learning methods to classify underlying perturbations that shape the timing of twitch force. To do this, we created a large twitch dataset using a spatially explicit Monte Carlo model of muscle contraction. Uniquely, we modified the rate constants of this model in line with mouse models of cardiac muscle disease and varied mutation penetrance. Ultimately, the results of this study show that machine learning models combined with biologically informed dimension reduction techniques can yield excellent classification accuracy of underlying muscle perturbations.
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Affiliation(s)
- Anthony Asencio
- Department of Biology, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Division of Cardiology, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
| | - Sage Malingen
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
| | - Kristina B. Kooiker
- Division of Cardiology, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
| | - Joseph D. Powers
- Department of Bioengineering, University of California, San Diego, San Diego, CA, USA
| | - Jennifer Davis
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
- Department of Laboratory Medicine Pathology, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
| | - Thomas Daniel
- Department of Biology, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
| | - Farid Moussavi-Harami
- Division of Cardiology, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
- Department of Laboratory Medicine Pathology, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
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7
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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 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] [What about the content of this article? (0)] [Affiliation(s)] [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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8
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Kooiker KB, Mohran S, Ma W, Flint GV, Kao KY, Qi L, McMillen T, Neys S, Mandrycky C, Irving TC, Geeves MA, Regnier M, Moussavi-Harami F. Elucidating the mechanism of Danicamtiv on force, kinetics, and myosin structure and function. Biophys J 2023; 122:453a. [PMID: 36784328 DOI: 10.1016/j.bpj.2022.11.2439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
| | - Saffie Mohran
- Bioengineering, University of Washington, Seattle, WA, USA
| | - Weikang Ma
- Biology, Illinois Institute of Technology, Chicago, IL, USA
| | - Galina V Flint
- Bioengineering, University of Washington, Seattle, WA, USA
| | - Kerry Y Kao
- Bioengineering, University of Washington, Seattle, WA, USA
| | - Lin Qi
- Biology, Illinois Institute of Technology, Chicago, IL, USA
| | | | | | | | | | - Michael A Geeves
- School of Biosciences, University of Kent, Canterbury, United Kingdom
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9
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Kooiker KB, Mohran S, Mahoney-Schaefer M, Freeman J, Geeves MA, Regnier M, Moussavi-Harami F. The effect of small molecule myosin modulators on ATP turnover in pig cardiac HMM using stopped flow spectroscopy. Biophys J 2023; 122:121a-122a. [PMID: 36782537 DOI: 10.1016/j.bpj.2022.11.827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
| | - Saffie Mohran
- Bioengineering, University of Washington, Seattle, WA, USA
| | | | | | - Michael A Geeves
- School of Biosciences, University of Kent, Canterbury, United Kingdom
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10
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Kooiker KB, Mohran S, Turner KL, Ma W, Flint G, Qi L, Gao C, Zheng Y, McMillen TS, Mandrycky C, Martinson A, Mahoney-Schaefer M, Freeman JC, Costales Arenas EG, Tu AY, Irving TC, Geeves MA, Tanner BCW, Regnier M, Davis J, Moussavi-Harami F. Danicamtiv increases myosin recruitment and alters the chemomechanical cross bridge cycle in cardiac muscle. bioRxiv 2023:2023.01.31.526380. [PMID: 36778318 PMCID: PMC9915609 DOI: 10.1101/2023.01.31.526380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Modulating myosin function is a novel therapeutic approach in patients with cardiomyopathy. Detailed mechanism of action of these agents can help predict potential unwanted affects and identify patient populations that can benefit most from them. Danicamtiv is a novel myosin activator with promising preclinical data that is currently in clinical trials. While it is known danicamtiv increases force and cardiomyocyte contractility without affecting calcium levels, detailed mechanistic studies regarding its mode of action are lacking. Using porcine cardiac tissue and myofibrils we demonstrate that Danicamtiv increases force and calcium sensitivity via increasing the number of myosin in the "on" state and slowing cross bridge turnover. Our detailed analysis shows that inhibition of ADP release results in decreased cross bridge turnover with cross bridges staying on longer and prolonging myofibril relaxation. Using a mouse model of genetic dilated cardiomyopathy, we demonstrated that Danicamtiv corrected calcium sensitivity in demembranated and abnormal twitch magnitude and kinetics in intact cardiac tissue. Significance Statement Directly augmenting sarcomere function has potential to overcome limitations of currently used inotropic agents to improve cardiac contractility. Myosin modulation is a novel mechanism for increased contraction in cardiomyopathies. Danicamtiv is a myosin activator that is currently under investigation for use in cardiomyopathy patients. Our study is the first detailed mechanism of how Danicamtiv increases force and alters kinetics of cardiac activation and relaxation. This new understanding of the mechanism of action of Danicamtiv can be used to help identify patients that could benefit most from this treatment.
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11
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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12
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Bretherton RC, Reichardt IM, Zabrecky KA, Goldstein AJ, Bailey LR, Bugg D, McMillen TS, Kooiker KB, Flint GV, Martinson A, Gunaje J, Koser F, Plaster E, Linke WA, Regnier M, Moussavi-Harami F, Sniadecki NJ, DeForest CA, Davis J. Correcting dilated cardiomyopathy with fibroblast-targeted p38 deficiency. bioRxiv 2023:2023.01.23.523684. [PMID: 36747691 PMCID: PMC9900749 DOI: 10.1101/2023.01.23.523684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Inherited mutations in contractile and structural genes, which decrease cardiomyocyte tension generation, are principal drivers of dilated cardiomyopathy (DCM)- the leading cause of heart failure 1,2 . Progress towards developing precision therapeutics for and defining the underlying determinants of DCM has been cardiomyocyte centric with negligible attention directed towards fibroblasts despite their role in regulating the best predictor of DCM severity, cardiac fibrosis 3,4 . Given that failure to reverse fibrosis is a major limitation of both standard of care and first in class precision therapeutics for DCM, this study examined whether cardiac fibroblast-mediated regulation of the heart's material properties is essential for the DCM phenotype. Here we report in a mouse model of inherited DCM that prior to the onset of fibrosis and dilated myocardial remodeling both the myocardium and extracellular matrix (ECM) stiffen from switches in titin isoform expression, enhanced collagen fiber alignment, and expansion of the cardiac fibroblast population, which we blocked by genetically suppressing p38α in cardiac fibroblasts. This fibroblast-targeted intervention unexpectedly improved the primary cardiomyocyte defect in contractile function and reversed ECM and dilated myocardial remodeling. Together these findings challenge the long-standing paradigm that ECM remodeling is a secondary complication to inherited defects in cardiomyocyte contractile function and instead demonstrate cardiac fibroblasts are essential contributors to the DCM phenotype, thus suggesting DCM-specific therapeutics will require fibroblast-specific strategies.
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13
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Asencio A, Malingen S, Regnier M, Daniel TL, Moussavi-Harami F. Predicting underlying pathology in simulated cardiac muscle twitches. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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14
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Mhatre KN, Moussavi-Harami F, Mathieu J, Hauschka SD, Murry CE, Regnier M. DeoxyATP producing hiPSC derived cardiomyocyte to restore cardiac function in heart failure. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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15
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Asencio A, Regnier M, Daniel TL, Moussavi-Harami F. Simulating Cardiac Muscle Mutations in a Compliant Lattice with Commonly Used Assays. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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16
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Ma W, Childers M, Murray J, Moussavi-Harami F, Gong H, Weiss R, Daggett V, Irving T, Regnier M. Myosin dynamics during relaxation in mouse soleus muscle and modulation by 2'-deoxy-ATP. J Physiol 2020; 598:5165-5182. [PMID: 32818298 PMCID: PMC7719615 DOI: 10.1113/jp280402] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/13/2020] [Indexed: 01/29/2023] Open
Abstract
KEY POINTS Skeletal muscle relaxation has been primarily studied by assessing the kinetics of force decay. Little is known about the resultant dynamics of structural changes in myosin heads during relaxation. The naturally occurring nucleotide 2-deoxy-ATP (dATP) is a myosin activator that enhances cross-bridge binding and kinetics. X-ray diffraction data indicate that with elevated dATP, myosin heads were extended closer to actin in relaxed muscle and myosin heads return to an ordered, resting state after contraction more quickly. Molecular dynamics simulations of post-powerstroke myosin suggest that dATP induces structural changes in myosin heads that increase the surface area of the actin-binding regions promoting myosin interaction with actin, which could explain the observed delays in the onset of relaxation. This study of the dATP-induced changes in myosin may be instructive for determining the structural changes desired for other potential myosin-targeted molecular compounds to treat muscle diseases. ABSTRACT Here we used time-resolved small-angle X-ray diffraction coupled with force measurements to study the structural changes in FVB mouse skeletal muscle sarcomeres during relaxation after tetanus contraction. To estimate the rate of myosin deactivation, we followed the rate of the intensity recovery of the first-order myosin layer line (MLL1) and restoration of the resting spacing of the third and sixth order of meridional reflection (SM3 and SM6 ) following tetanic contraction. A transgenic mouse model with elevated skeletal muscle 2-deoxy-ATP (dATP) was used to study how myosin activators may affect soleus muscle relaxation. X-ray diffraction evidence indicates that with elevated dATP, myosin heads were extended closer to actin in resting muscle. Following contraction, there is a slight but significant delay in the decay of force relative to WT muscle while the return of myosin heads to an ordered resting state was initially slower, then became more rapid than in WT muscle. Molecular dynamics simulations of post-powerstroke myosin suggest that dATP induces structural changes in myosin that increase the surface area of the actin-binding regions, promoting myosin interaction with actin. With dATP, myosin heads may remain in an activated state near the thin filaments following relaxation, accounting for the delay in force decay and the initial delay in recovery of resting head configuration, and this could facilitate subsequent contractions.
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Affiliation(s)
- Weikang Ma
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago IL
| | - Matthew Childers
- Department of Bioengineering, University of Washington, Seattle WA
| | - Jason Murray
- Department of Bioengineering, University of Washington, Seattle WA
| | | | - Henry Gong
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago IL
| | - Robert Weiss
- Department of Biomedical Sciences, Cornell University, Ithaca NY
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle WA
| | - Thomas Irving
- BioCAT, Department of Biological Sciences, Illinois Institute of Technology, Chicago IL
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle WA
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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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Kooiker KB, Berisha D, Martinson A, Tudor J, Freeman J, Branley C, Moussavi-Harami F. Ribonucleotide Reductase is Essential in Adult Cardiomyocytes. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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19
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Kooiker KB, Gan QF, Yu M, Cheng Y, Sa N, Zhong M, McMillen T, Moussavi-Harami F, Regnier M. Two Small Molecule Inhibitors of Myosin Decrease Force and Increase Rates of Relaxation in Demembranated Rat Left Ventricular Tissue. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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20
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Branley CE, Moussavi-Harami F, Kooiker KB, Regnier M, Tardiff JC, Tudor J, Freeman J. Two Myofilament-Based Approaches to Prevent Genetic Dilated Cardiomyopathy. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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21
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Robeson KZ, Moussavi-Harami F, Davis J, Regnier M. Abstract 911: New Promoters to Improve the Efficiency of Cardiac Gene Therapies Using 2 Deoxy-ATP. Circ Res 2019. [DOI: 10.1161/res.125.suppl_1.911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Traditional inotropes work by altering intracellular calcium levels but have many off-target effects. Myosin activators have shown promise for treating the increasing number of heart failure patients today, with one drug in phase three clinical trials. These drugs work by increasing the affinity of myosin for actin. Our lab has demonstrated that the small molecule 2 deoxy-ATP (dATP) can improve both myosin binding to and myosin release from actin. We have also demonstrated the efficacy of a cardiac targeted gene therapy to improve heart function via increasing intracellular dATP levels. This was done by overexpressing ribonucleotide reductase (RNR)—the rate-limiting enzyme in de novo dNTP synthesis. This cardiac therapy, using the cardiac troponin T (cTnT) promoter, was effective in a mouse model but provided variable results in a large animal model due to delivery challenges. Therefore, we are now investigating alternative promoters to deliver dATP to cardiomyocytes and/or other striated muscles. Here we present our investigation of the CK8 promoter for striated muscle specific delivery of RNR. We report that the CK8 promoter was able to produce a greater than fourfold increase in mouse ventricular tissue dATP levels above that seen with the cTnT promoter (2.0 to 8.4 pmol/mg; P<0.01). RNR was also delivered to skeletal muscle with a twofold increase in gastrocnemius dATP levels (0.62 to 1.31 pmol/mg; P<0.01). We have also been investigating cardiac fibroblasts as a route to deliver dATP to cardiomyocytes. We have shown that
in vitro
fibroblasts can transmit dATP to coupled cardiomyocytes through gap junctions, indicating that overexpressing RNR in cardiac fibroblasts could increase dATP levels in both cell types. Previous research has shown that proliferating fibroblasts have increased levels of dATP, and preliminary results in our lab show that differentiated myofibroblasts have decreased levels of dATP. We therefore hypothesize that increased dATP in cardiac fibroblasts will not only improve contraction in coupled cardiomyocytes but may also inhibit fibroblast transdifferentiation into collagen producing myofibroblasts.
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Chiao YA, Kooiker K, Cheng Y, Powers J, Razumova M, Granzier H, Regnier M, Rabinovitch P, Moussavi-Harami F. Abstract 903: Rapamycin Treatment Reduces Myocardial Stiffness and Promotes Cardiomyocyte Relaxation to Restore Diastolic Function in Old Murine Hearts. Circ Res 2019. [DOI: 10.1161/res.125.suppl_1.903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aging is associated with a decline in diastolic function and is a strong risk factor for heart failure with preserved ejection fraction (HFpEF), which has no effective treatment. We previously showed that late-life rapamycin treatment can reverse age-related cardiac dysfunction in mice. However, the mechanisms of the reversal of diastolic dysfunction have not been established. The objective of this study is to determine the mechanisms by which rapamycin reverses age-related diastolic dysfunction.
To study the effects of rapamycin on myocardial stiffness, we assessed the passive length-tension relationship of demembranated trabecular muscle from young, old control and old rapamycin-treated mice. We observed a substantial increase in the slope of the length-tension curve with aging, indicating an age-related increase in myocardial stiffness. The age-related increase in myocardial stiffness was significantly reduced by rapamycin treatment, by a mechanism independent of titin isoform shift. We measured the force-calcium relationship of the demembranated trabeculae and revealed an age-related increase in Ca
2+
sensitivity, as indicated by a left-shift of the force-pCa curve, which was partially restored after rapamycin treatment (pCa50: 5.59±0.04 for young controls; 5.76±0.04 for old controls; and 5.65±0.04 for old rapamycin-treated group). To investigate the changes at myofibril level, we assessed kinetic properties of control and rapamycin-treated myofibrils following maximal (pCa 4.0) and submaximal (pCa 5.6) Ca
2+
activation. Myofibrils from rapamycin-treated mice displayed increased rate of the fast phase of relaxation (kREL, fast) compared to old control at both maximal and submaximal Ca
2+
levels, potentially due to reduced myofibril Ca
2+
sensitivity. Studies have detected age-related reductions in expression and activity of SERCA2, which is responsible for SR calcium reuptake during diastole. In this study, we showed that rapamycin increased SERCA2 expression, which may improve cardiomyocyte relaxation.
In summary, our results suggest that rapamycin normalizes age-related increases in myocardial stiffness and Ca
2+
sensitivity and improves myofibril relaxation kinetics, therefore, improving diastolic function.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Powers JD, Flint G, Tardiff J, Regnier M, Moussavi-Harami F, Davis J. Predicting and Preventing Myocardial Remodeling in a Murine Model of Dilated Cardiomyopathy. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.1436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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26
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Kooiker KB, Powers JD, Tardiff J, Regnier M, Davis J, Moussavi-Harami F. Engineered Thin Filament Mutation to Increase Calcium Sensitivity of Force in Tropomyosin Mutation of Dilated Cardiomyopathy. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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27
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Moussavi-Harami F, Razumova MV, Klaiman JM, Cheng Y, Tardiff JC, Regnier M. Abstract 439: Elevating 2-deoxy Adenosine Triphosphate Improves Contraction in a Mouse Model of Genetic Dilated Cardiomyopathy. Circ Res 2018. [DOI: 10.1161/res.123.suppl_1.439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Several studies have identified reduced tension and Ca
2+
sensitivity as key regulators that precipitate dilated cardiomyopathy (DCM). We are developing a novel therapy to increase tension using adeno-associated viral (AAV) vectors that increase intracellular 2 deoxy-ATP (dATP) via overexpression of the enzyme ribonucleotide reductase (RNR). We have reported that dATP substitution for ATP increases the magnitude and rate of contraction and that RNR overexpression increases intracellular dATP and enhances cardiac function.
Here we use a multiscale approach to test the effect of dATP in a genetic model of dilated cardiomyopathy (DCM) with a missense mutation (D230N) in alpha-tropomyosin (Tm). Using recombinant proteins in the
in vitro
motility assay, we found that filament velocity was lower with D230N compared to WT Tm (2.03±0.04 vs. 2.44±0.04 μm/s). This deficit was corrected when dATP was substituted for ATP (2.90±0.04 μm/s). Next, we used transgenic D230N mice that show progressive ventricular dilation and systolic dysfunction. Intact and demembranated trabeculae from these mice have decreased tension and calcium sensitivity of force, and loss of length-dependent activation (LDA) compared to WT mice. Substitution of dATP for ATP, increased Ca
2+
sensitivity in D230N Tm myocardium (pCa
50
=5.48±0.02 vs. 5.57±0.02) and restored LDA. Complete replacement of ATP with dATP resulted in an ~70% increase in force at submaximal [Ca
2+
] and force at submaximal Ca
2+
was significantly increased by replacement of only 5% of the nucleotide pool with dATP. For isolated myofibrils from D230N Tm and WT mice, tension at submaximal Ca
2+
(pCa=5.6) was lower in D230N mice compared to WT mice (51±4 vs. 75±8 mN/mm
2
) and this deficit was improved with dATP (68±5 mN/mm
2
). Similarly, the rate of activation in D230N myofibrils was slower than in WT mice (2.1±0.2 vs.3.3±0.2 s
-1
) and partially corrected with dATP (2.7±0.2 s
-1
). These results demonstrate that enhanced cross bridge binding, via increasing dATP, can recover lost contractile function in a thin filament mutation model of DCM. In ongoing studies, we are testing the ability of elevated dATP, via AAV- RNR, to protect against reduced systolic function and progressive ventricular dilation in 2-3 week old D230N mice
.
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Abstract
Heart failure with preserved ejection fraction (HFpEF) accounts for half of all heart failure in the USA, increases in prevalence with aging, and has no effective therapies. Intriguingly, the pathophysiology of HFpEF has many commonalities with the aged cardiovascular system including reductions in diastolic compliance, chronotropic defects, increased resistance in the peripheral vasculature, and poor energy substrate utilization. Decreased exercise capacity is a cardinal symptom of HFpEF. However, its severity is often out of proportion to changes in cardiac output. This observation has led to studies of muscle function in HFpEF revealing structural, biomechanical, and metabolic changes. These data, while incomplete, support a hypothesis that similar to aging, HFPEF is a systemic process. Understanding the mechanisms leading to exercise intolerance in this condition may lead to strategies to improve morbidity in both HFpEF and aging.
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Affiliation(s)
- Stephen D Farris
- Department of Medicine, Division of Cardiology, University of Washington School of Medicine, Seattle, WA, USA
| | - Farid Moussavi-Harami
- Department of Medicine, Division of Cardiology, University of Washington School of Medicine, Seattle, WA, USA
| | - April Stempien-Otero
- Department of Medicine, Division of Cardiology, University of Washington School of Medicine, Seattle, WA, USA.
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Powers JD, Moussavi-Harami F, Tardiff JC, Davis J, Regnier M. Engineered Thin Filament Mutations to Study the Sarcomere Length Dependence of Cardiac Muscle Contractility. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.1769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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30
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Murray J, Odom G, Olafsson S, Hauschka S, Chamberlain J, Moussavi-Harami F, Regnier M. AAV-Mediated Delivery of Ribonucleotide Reductase and Microdystrophin Rescues Function in Dystrophic Mice. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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31
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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32
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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33
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Powers JD, Moussavi-Harami F, Razumova M, Tardiff J, Regnier M. Abstract 226: Elucidating the Mechanism of Reduced Length-dependent Activation Due to a Dilated Cardiomyopathy-associated Mutation in Tropomyosin. Circ Res 2017. [DOI: 10.1161/res.121.suppl_1.226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
At the subcellular level, the Frank-Starling law of the heart is described by an increase in calcium sensitivity and force with increased sarcomere length (SL). We examine how this relationship is affected by a dilated cardiomyopathy-associated mutation in tropomyosin (D230N, denoted Tm
D230N
) by measuring contractility of intact and permeabilized cardiac muscle preparations at short (2.0 μm) and long (2.3 μm) SL. Transgenic mouse hearts containing the Tm
D230N
mutation have significantly dilated hearts and reduced cardiac output by ~6 months of age. Intact trabeculae were electrically stimulated and paced at 1 Hz with oxygenated solution (30°C) circulating through the experimental chamber, and permeabilized preparations were bathed in solutions (15°C) of progressively increased [Ca
2+
] for measures of steady-state force. For intact muscle we found that the Tm
D230N
mutation results in significantly reduced twitch forces at SL 2.0 and 2.3 μm relative to wild-type (WT). Also, WT trabeculae displayed a significant increase in twitch force upon increase in SL (as expected) but Tm
D230N
trabeculae did not, demonstrating a loss of SL dependence of contraction. In permeabilized preparations, maximal activation (pCa 4.5) of both WT and Tm
D230N
preparations exhibited significant SL-dependent increases in force. However, at submaximal Ca
2+
(pCa 5.8), where the heart operates, WT preparations had significant increases in force with increasing length (comparing SL 2.0 to 2.3 μm), while this length-dependence of force augmentation in Tm
D230N
was absent. The increase in pCa
50
(pCa that produces half-maximal force) going from SL 2.0 to 2.3 μm was significantly less for Tm
D230N
preparations compared to WT, owing to a significantly smaller increase in pCa
50
at SL 2.3 μm (the pCa
50
at SL 2.0 μm was not significantly different between WT and Tm
D230N
). These results suggest that the Tm
D230N
mutation limits an increase in the Ca
2+
sensitivity of contraction as the muscle lengthens by damping thin filament activation. To further examine length-dependent effects of the Tm
D230N
mutation, future experiments will test conditions that augment cross-bridge binding/inhibition, and other models of dilated cardiomyopathy that inhibit thin filament activation. Funding: HL111197
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Moussavi-Harami F, Razumova MV, Klaiman JM, Bugg D, Regnier M, Davis J. Abstract 69: Cardiac Fibrosis Induced by Mkk6-p38 Activation Alters Myocardial Stiffness and Myofilament Function. Circ Res 2017. [DOI: 10.1161/res.121.suppl_1.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Heart failure with preserved ejection fraction (HFpEF) accounts for at least half of the patients with heart failure, but to date there are no proven therapies for these patients. Cardiac fibrosis and increased collagen content plays an important role in the pathophysiology of HFpEF. Studies in human HFpEF patients have indicated increased cardiac fibrosis, myocardial stiffness and myofilament calcium sensitivity. However, it is unclear how and if cardiac fibrosis directly alters myofilament function. In this study we used a new model of cardiac fibrosis genetically induced by the constitutive activation of MKK6-p38 (MKK6-Tg) signaling specifically in resident cardiac fibroblasts to determine the effect of fibrosis on myofilament stiffness and function. The MKK6-Tg mice develop interstitial and perivascular fibrosis in the heart accompanied with severe diastolic dysfunction, although systolic function remains normal. We measured the passive stiffness and isometric contractile properties of demembranated papillary muscle preparations. Our results show an increase in passive stiffness in demembranated papillary muscles from MKK6-Tg mice compared to NTG littermates when stretched to 24% from sarcomere length of 2.0 μM. Passive tension at SL=2.3 was significantly increased in MKK6-Tg mice (28±4 vs. 13±3 mN/mm
2
, P<0.05) compared to NTG mice, which was ascribed to changes in Titin isoform as well as extracellular matrix composition. The MKK6-Tg mice also show an increase in Ca
2+
sensitivity (pCa
50
=5.72±0.05 vs. 5.56±0.02, P<0.05). This was associated with an increased rate of force redevelopment in MKK6-Tg mice compared to NTG littermates (k
TR
=35±8 vs. 22±3 s
-1
). Towards understanding the mechanism of these myofilament changes we performed phosphate affinity electrophoresis and saw decreased phosphorylation of both Troponin I and Troponin T in MKK6-Tg hearts. There was no change in troponin I phosphorylation level at Ser23/24, indicating role of none-PKA mediated phosphorylation in mechanical changes seen in this model.
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Murray JD, Guan X, Moussavi-Harami F, Olafsson SS, Murry CE, Regnier M. Abstract 369: Engineering Rrm2 to Elevate 2-deoxy-ATP and Improve Cardiomyocyte Function. Circ Res 2017. [DOI: 10.1161/res.121.suppl_1.369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Overexpression of ribonucleotide reductase (RNR) in cardiomyocytes increases the amount of cytosolic 2-deoxy-ATP (dATP), which can be used by myosin and significantly increases contraction of cardiac muscle at all levels of calcium activation. Our group is working to develop enhanced dATP as a therapeutic option for heart failure. We have demonstrated that virally-mediated overexpression of RNR elevates dATP and increases the rate and magnitude of contraction and increases left ventricular contraction in normal hearts as well as rodent models of myocardial infarction and dilated cardiomyopathy. RNR is a heterotetramer containing two subunits, Rrm1 and Rrm2. While cardiomyocyte-specific overexpression of Rrm1 is stable, we have observed high variability in expression levels of the Rrm2 subunit in multiple disease models. We hypothesized that this variability was largely due to protein degradation via the ubiquitin-proteasome complex (UPC). We found that pharmacological inhibition of proteasome activity leads to increased expression of Rrm2 in virally-transduced cardiomyocytes
in vitro.
To confirm the hypothesis that the overexpressed Rrm2 is degraded via UPC-mediated degradation, we engineered mutations in specific ubiquitin-binding degrons of the Rrm2 gene. Transfecting human induced pluripotent stem cell-derived cardiomyocytes resulted in higher levels of Rrm2 than those overexpressing wild-type protein and resulted in higher levels of cytosolic dATP as measured by Liquid chromatography-mass spectrometry. Ongoing and planned experiments will compare the effects of this engineered mutation on Rrm2 overexpression, dATP production, and contractility in cultured cardiomyocytes. Our goal is to develop an improved RNR vector that will be resistant to degradation through the ubiquitin-proteasome pathway and therefore enable more stable and consistent RNR enzyme activity and deoxynucleotide levels of cardiomyocytes transduced
in vivo.
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Powers JD, Moussavi-Harami F, Razumova M, Tardiff J, Regnier M. The Frank-Starling Mechansim is Attenuated by a Dilated Cardiomyopathy-Associated Tropomyosin Mutation. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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37
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Murray JD, Moussavi-Harami F, Regnier M. The Effect of Ribonucleotide Reductase Overexpression on Cardiomyocyte Metabolism. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.2265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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38
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Moussavi-Harami F, Razumova MV, Farris S, Flint GV, Olafsson S, Steczina S, Cheng Cheng Y, Racca AW, Stempien-Otero A, Regnier M. Cardiac Fibrosis Alters Calcium Sensitivity and Myofilament Relaxation. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.1594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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39
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Murray JD, Moussavi-Harami F, Marcinek D, Regnier M. Ribonucleotide Reductase Overexpression does not Alter Cardiomyocyte Mitochondrial Respiration. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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40
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Racca AW, Klaiman JM, Pioner JM, Cheng Y, Beck AE, Moussavi-Harami F, Bamshad MJ, Regnier M. Contractile properties of developing human fetal cardiac muscle. J Physiol 2015; 594:437-52. [PMID: 26460603 DOI: 10.1113/jp271290] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/06/2015] [Indexed: 01/10/2023] Open
Abstract
KEY POINTS The contractile properties of human fetal cardiac muscle have not been previously studied. Small-scale approaches such as isolated myofibril and isolated contractile protein biomechanical assays allow study of activation and relaxation kinetics of human fetal cardiac muscle under well-controlled conditions. We have examined the contractile properties of human fetal cardiac myofibrils and myosin across gestational age 59-134 days. Human fetal cardiac myofibrils have low force and slow kinetics of activation and relaxation that increase during the time period studied, and kinetic changes may result from structural maturation and changes in protein isoform expression. Understanding the time course of human fetal cardiac muscle structure and contractile maturation can provide a framework to study development of contractile dysfunction with disease and evaluate the maturation state of cultured stem cell-derived cardiomyocytes. ABSTRACT Little is known about the contractile properties of human fetal cardiac muscle during development. Understanding these contractile properties, and how they change throughout development, can provide valuable insight into human heart development, and provide a framework to study the early stages of cardiac diseases that develop in utero. We characterized the contractile properties of isolated human fetal cardiac myofibrils across 8-19 weeks of gestation. Mechanical measurements revealed that in early stages of gestation there is low specific force and slow rates of force development and relaxation, with increases in force and the rates of activation and relaxation as gestation progresses. The duration and slope of the initial, slow phase of relaxation, related to myosin detachment and thin filament deactivation rates, decreased with gestation age. F-actin sliding on human fetal cardiac myosin-coated surfaces slowed significantly from 108 to 130 days of gestation. Electron micrographs showed human fetal muscle myofibrils elongate and widen with age, but features such as the M-line and Z-band are apparent even as early as day 52. Protein isoform analysis revealed that β-myosin is predominantly expressed even at the earliest time point studied, but there is a progressive increase in expression of cardiac troponin I (TnI), with a concurrent decrease in slow skeletal TnI. Together, our results suggest that cardiac myofibril force production and kinetics of activation and relaxation change significantly with gestation age and are influenced by the structural maturation of the sarcomere and changes in contractile filament protein isoforms.
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Affiliation(s)
- Alice W Racca
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Jordan M Klaiman
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - J Manuel Pioner
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Italy
| | - Yuanhua Cheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Anita E Beck
- Department of Pediatrics, University of Washington, Seattle, WA, USA.,Seattle Children's Hospital, Seattle, WA, USA
| | - Farid Moussavi-Harami
- Division of Cardiology, Department of Internal Medicine, University of Washington, Seattle, WA, USA
| | - Michael J Bamshad
- Department of Pediatrics, University of Washington, Seattle, WA, USA.,Seattle Children's Hospital, Seattle, WA, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA, USA.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.,Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Moussavi-Harami F, Razumova MV, Cheng Y, Odom G, Teichman S, Tardiff J, Hauschka SD, Chamberlain JS, Murry CM, Regnier M. 11. Gene Therapy Mediated Increase in dATP Improves Cardiac Performance in Models of Systolic Heart Failure. Mol Ther 2015. [DOI: 10.1016/s1525-0016(16)33615-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Moussavi-Harami F, Razumova MV, Racca AW, Cheng Y, Stempien-Otero A, Regnier M. 2-Deoxy adenosine triphosphate improves contraction in human end-stage heart failure. J Mol Cell Cardiol 2014; 79:256-63. [PMID: 25498214 DOI: 10.1016/j.yjmcc.2014.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 11/16/2014] [Accepted: 12/02/2014] [Indexed: 01/10/2023]
Abstract
We are developing a novel treatment for heart failure by increasing myocardial 2 deoxy-ATP (dATP). Our studies in rodent models have shown that substitution of dATP for adenosine triphosphate (ATP) as the energy substrate in vitro or elevation of dATP in vivo increases myocardial contraction and that small increases in the native dATP pool of heart muscle are sufficient to improve cardiac function. Here we report, for the first time, the effect of dATP on human adult cardiac muscle contraction. We measured the contractile properties of chemically-demembranated multicellular ventricular wall preparations and isolated myofibrils from human subjects with end-stage heart failure. Isometric force was increased at both saturating and physiologic Ca(2+) concentrations with dATP compared to ATP. This resulted in an increase in the Ca(2+) sensitivity of force (pCa50) by 0.06 pCa units. The rate of force redevelopment (ktr) in demembranated wall muscle was also increased, as was the rate of contractile activation (kACT) in isolated myofibrils, indicating increased cross-bridge binding and cycling compared with ATP in failing human myocardium. These data suggest that dATP could increase dP/dT and end systolic pressure in failing human myocardium. Importantly, even though the magnitude and rate of force development were increased, there was no increase in the time to 50% and 90% myofibril relaxation. These data, along with our previous studies in rodent models, show the promise of elevating myocardial dATP to enhance contraction and restore cardiac pump function. These data also support further pre-clinical evaluation of this new approach for treating heart failure.
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Affiliation(s)
- Farid Moussavi-Harami
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Maria V Razumova
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Alice W Racca
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Yuanhua Cheng
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - April Stempien-Otero
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98195, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA.
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Moussavi-Harami F, Razumova MV, Cheng Y, Racca AW, Stempien-Otero A, Regnier M. Abstract 35: 2-deoxy Adenosine Triphosphate Improves Contraction In Human End-stage Heart Failure. Circ Res 2014. [DOI: 10.1161/res.115.suppl_1.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We are developing a novel approach to treat heart failure that involves adeno-associated virus vectors to elevate intracellular 2 deoxy-ATP (dATP) via increased expression of the enzyme Ribonucleotide Reductase. Our studies in rodents have shown that substitution of dATP for ATP as the energy substrate increases contraction in striated muscle. Here we report for the first time the effect of dATP on human cardiac muscle contraction. We measured the contractile properties of demembranated multicellular ventricular wall preparations and isolated myofibrils from adult human heart tissue obtained from twelve patients undergoing surgery for cardiac transplantation or placement of left ventricular-assist device for end-stage heart failure. Isometric force at saturating calcium concentration was increased by about ten percent from 38.6±3.8 mN/mm2 to 42.8±4.2 mN/mm2 when dATP was substituted for ATP (P<0.001). The effect was even greater at physiologic calcium concentrations with an approximate increase of thirty percent. Isometric force increased from 21.2 ± 6.1 mN/mm2 to 26.4± 6.4 mN/mm2 (p<0.001) at pCa=5.6 and from 22.6 ± 5.9 mN/mm2 to 27.5± 6.3 mN/mm2 (p<0.001) at pCa=5.8 with dATP for ATP substitution. The result was an increase in the Ca2+ sensitivity of force as the [Ca2+] required to elicit half maximum force (pCa50) increased by 0.08 units from 5.68±0.03 to 5.79±0.03 (N=24, P< 0.001). The maximum rate of force redevelopment (ktr) in demembranated wall muscle increased (0.82±0.01 s-1 vs. 0.62±0.01 s-1, P< 0.05), as was the rate of contractile activation in isolated myofibrils (0.80±0.06 s-1 vs. 0.57±0.06 s-1, P<0.01) suggesting dATP may increase dP/dT in failing human myocardium. Importantly, there was no slowing of relaxation, as the time to 50% and 90% myofibril relaxation were unchanged. Purified myosin from failing human myocardium showed enhanced NTPase activity with dATP (0.89±0.17 s-1/head) vs. ATP (0.55±0.20 s-1/head, P<0.05). In conclusion, the data strongly suggest dATP increases cross-bridge cycling, compared with ATP in failing human myocardium and shows promise in restoring cardiac pump function. These data support a novel myofilament approach for treating heart failure that warrants further pre-clinical evaluation.
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Hartman ME, Librande JR, Medvedev IO, Ahmad RN, Moussavi-Harami F, Gupta PP, Chien WM, Chin MT. An optimized and simplified system of mouse embryonic stem cell cardiac differentiation for the assessment of differentiation modifiers. PLoS One 2014; 9:e93033. [PMID: 24667642 PMCID: PMC3965510 DOI: 10.1371/journal.pone.0093033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 02/28/2014] [Indexed: 12/19/2022] Open
Abstract
Generating cardiomyocytes from embryonic stem cells is an important technique for understanding cardiovascular development, the origins of cardiovascular diseases and also for providing potential reagents for cardiac repair. Numerous methods have been published but often are technically challenging, complex, and are not easily adapted to assessment of specific gene contributions to cardiac myocyte differentiation. Here we report the development of an optimized protocol to induce the differentiation of mouse embryonic stem cells to cardiac myocytes that is simplified and easily adapted for genetic studies. Specifically, we made four critical findings that distinguish our protocol: 1) mouse embryonic stem cells cultured in media containing CHIR99021 and PD0325901 to maintain pluripotency will efficiently form embryoid bodies containing precardiac mesoderm when cultured in these factors at a reduced dosage, 2) low serum conditions promote cardiomyocyte differentiation and can be used in place of commercially prepared StemPro nutrient supplement, 3) the Wnt inhibitor Dkk-1 is dispensable for efficient cardiac differentiation and 4) tracking differentiation efficiency may be done with surface expression of PDGFRα alone. In addition, cardiac mesodermal precursors generated by this system can undergo lentiviral infection to manipulate the expression of specific target molecules to assess effects on cardiac myocyte differentiation and maturation. Using this approach, we assessed the effects of CHF1/Hey2 on cardiac myocyte differentiation, using both gain and loss of function. Overexpression of CHF1/Hey2 at the cardiac mesoderm stage had no apparent effect on cardiac differentiation, while knockdown of CHF1/Hey2 resulted in increased expression of atrial natriuretic factor and connexin 43, suggesting an alteration in the phenotype of the cardiomyocytes. In summary we have generated a detailed and simplified protocol for generating cardiomyocytes from mES cells that is optimized for investigating factors that affect cardiac differentiation.
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Affiliation(s)
- Matthew E. Hartman
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Jason R. Librande
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Ivan O. Medvedev
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Rabiah N. Ahmad
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Farid Moussavi-Harami
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Pritha P. Gupta
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Wei-Ming Chien
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Michael T. Chin
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Liu Y, Korte FS, Moussavi-Harami F, Yu M, Razumova M, Regnier M, Chin MT. Transcription factor CHF1/Hey2 regulates EC coupling and heart failure in mice through regulation of FKBP12.6. Am J Physiol Heart Circ Physiol 2012; 302:H1860-70. [PMID: 22408025 DOI: 10.1152/ajpheart.00702.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heart failure is a leading cause of morbidity and mortality in Western society. The cardiovascular transcription factor CHF1/Hey2 has been linked to experimental heart failure in mice, but the mechanisms by which it regulates myocardial function remain incompletely understood. The objective of this study was to determine how CHF1/Hey2 affects development of heart failure through examination of contractility in a myocardial knockout mouse model. We generated myocardial-specific knockout mice. At baseline, cardiac function was normal, but, after aortic banding, the conditional knockout mice demonstrated a greater increase in ventricular weight-to-body weight ratio compared with control mice (5.526 vs. 4.664 mg/g) and a significantly decreased ejection fraction (47.8 vs. 72.0% control). Isolated cardiac myocytes from these mice showed decreased calcium transients and fractional shortening after electrical stimulation. To determine the molecular basis for these alterations in excitation-contraction coupling, we first measured total sarcoplasmic reticulum calcium stores and calcium-dependent force generation in isolated muscle fibers, which were normal, suggesting a defect in calcium cycling. Analysis of gene expression demonstrated normal expression of most genes known to be involved in myocardial calcium cycling, with the exception of the ryanodine receptor binding protein FKBP12.6, which was expressed at increased levels in the conditional knockout hearts. Treatment of the isolated knockout myocytes with FK506, which inhibits the association of FKBP12.6 with the ryanodine receptor, restored contractile function. These findings demonstrate that conditional deletion of CHF1/Hey2 in the myocardium leads to abnormalities in calcium handling mediated by FKBP12.6 that predispose to pressure overload-induced heart failure.
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Affiliation(s)
- Yonggang Liu
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington 98109, USA
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Wu L, Chien WM, Hartman ME, Moussavi-Harami F, Liu Y, Chin MT. Regulation of MMP10 expression by the transcription factor CHF1/Hey2 is mediated by multiple E boxes. Biochem Biophys Res Commun 2011; 415:662-8. [PMID: 22079635 DOI: 10.1016/j.bbrc.2011.10.132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 10/28/2011] [Indexed: 10/15/2022]
Abstract
The cardiovascular restricted bHLH transcription factor CHF1/Hey2 has been reported to play an important role in regulation of vascular smooth muscle phenotype and gene expression, but the downstream target genes that mediate these effects have not been completely elucidated. We have previously found that loss of CHF1/Hey2 in vascular smooth muscle cells leads to dysregulated expression of the matrix metalloproteinase gene MMP10 after treatment with PDGF. Here we report that loss or knockdown of CHF1/Hey2 in vascular smooth muscle cells leads to increased expression and activity of MMP10 at baseline, suggesting a direct effect of CHF1/Hey2 on MMP10 promoter regulation. To test this hypothesis, we assessed the effects of CHF1/Hey2 on a 2.5 kb MMP10 promoter region upstream of the transcriptional start site. We found that this region contains multiple elements including 12 E-boxes that mediate constitutive activity and repression by CHF1/Hey2 in 293T cells and A7r5 smooth muscle cells. Surprisingly, mutation of these E-boxes not only abolished CHF1/Hey2 repression, but also diminished constitutive expression. In addition, we observed that some of these mutations unmasked an activator function for CHF1/Hey2, which has not been previously described. These findings support the hypothesis that CHF1/Hey2 is an important regulator of MMP10 expression.
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Affiliation(s)
- Ling Wu
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98109, United States
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Moussavi-Harami F, Mollano A, Martin JA, Ayoob A, Domann FE, Gitelis S, Buckwalter JA. Intrinsic radiation resistance in human chondrosarcoma cells. Biochem Biophys Res Commun 2006; 346:379-85. [PMID: 16765318 DOI: 10.1016/j.bbrc.2006.05.158] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Accepted: 05/03/2006] [Indexed: 10/24/2022]
Abstract
Human chondrosarcomas rarely respond to radiation treatment, limiting the options for eradication of these tumors. The basis of radiation resistance in chondrosarcomas remains obscure. In normal cells radiation induces DNA damage that leads to growth arrest or death. However, cells that lack cell cycle control mechanisms needed for these responses show intrinsic radiation resistance. In previous work, we identified immortalized human chondrosarcoma cell lines that lacked p16(ink4a), one of the major tumor suppressor proteins that regulate the cell cycle. We hypothesized that the absence of p16(ink4a) contributes to the intrinsic radiation resistance of chondrosarcomas and that restoring p16(ink4a) expression would increase their radiation sensitivity. To test this we determined the effects of ectopic p16(ink4a) expression on chondrosarcoma cell resistance to low-dose gamma-irradiation (1-5 Gy). p16(ink4a) expression significantly increased radiation sensitivity in clonogenic assays. Apoptosis did not increase significantly with radiation and was unaffected by p16(ink4a) transduction of chondrosarcoma cells, indicating that mitotic catastrophe, rather than programmed cell death, was the predominant radiation effect. These results support the hypothesis that p16(ink4a) plays a role in the radiation resistance of chondrosarcoma cell lines and suggests that restoring p16 expression will improve the radiation sensitivity of human chondrosarcomas.
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Affiliation(s)
- Farid Moussavi-Harami
- Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, 52242, USA
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Martin JA, Klingelhutz AJ, Moussavi-Harami F, Buckwalter JA. Effects of Oxidative Damage and Telomerase Activity on Human Articular Cartilage Chondrocyte Senescence. J Gerontol A Biol Sci Med Sci 2004; 59:324-37. [PMID: 15071075 DOI: 10.1093/gerona/59.4.b324] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Senescence compromises the ability of chondrocytes to maintain and repair articular cartilage. We hypothesized that oxidative stress and telomere loss contribute to chondrocyte senescence. To test this hypothesis, we compared the growth of human articular cartilage chondrocytes incubated in 5% O2 and 21% O2. Cells grown in 5% O2 reached 60 population doublings (PD) before senescing, but growth in 21% O2 induced DNA damage and premature senescence at less than 40 PD. Human telomerase reverse transcriptase (hTERT)-transduction failed to prevent chondrocyte senescence in 21% O2, but allowed 1 of 3 chondrocyte strains to exceed 90 PD in 5% O2. These results show that oxidative stress causes premature chondrocyte senescence. They may help explain the increased risk of osteoarthritis with age and after joint trauma and inflammation, and suggest that minimizing oxidative damage will help produce optimal results for chondrocyte transplantation.
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Affiliation(s)
- James A Martin
- Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa City, IA 52242, USA
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Moussavi-Harami F, Duwayri Y, Martin JA, Moussavi-Harami F, Buckwalter JA. Oxygen effects on senescence in chondrocytes and mesenchymal stem cells: consequences for tissue engineering. Iowa Orthop J 2004; 24:15-20. [PMID: 15296200 PMCID: PMC1888421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Primary isolates of chondrocytes and mesenchymal stem cells are often insufficient for cell-based autologous grafting procedures, necessitating in vitro expansion of cell populations. However, the potential for expansion is limited by cellular senescence, a form of irreversible cell cycle arrest regulated by intrinsic and extrinsic factors. Intrinsic mechanisms common to most somatic cells enforce senescence at the so-called "Hayflick limit" of 60 population doublings. Termed "replicative senescence", this mechanism prevents cellular immortalization and suppresses oncogenesis. Although it is possible to overcome the Hayflick limit by genetically modifying cells, such manipulations are regarded as prohibitively dangerous in the context of tissue engineering. On the other hand, senescence associated with extrinsic factors, often called "stress-induced" senescence, can be avoided simply by modifying culture conditions. Because stress-induced senescence is "premature" in the sense that it can halt growth well before the Hayflick limit is reached, growth potential can be significantly enhanced by minimizing culture related stress. Standard culture techniques were originally developed to optimize the growth of fibroblasts but these conditions are inherently stressful to many other cell types. In particular, the 21% oxygen levels used in standard incubators, though well tolerated by fibroblasts, appear to induce oxidative stress in other cells. We reasoned that chondrocytes and MSCs, which are adapted to relatively low oxygen levels in vivo, might be sensitive to this form of stress. To test this hypothesis we compared the growth of MSC and chondrocyte strains in 21% and 5% oxygen. We found that incubation in 21% oxygen significantly attenuated growth and was associated with increased oxidant production. These findings indicated that sub-optimal standard culture conditions sharply limited the expansion of MSC and chondrocyte populations and suggest that cultures for grafting purposes should be maintained in a low-oxygen environment.
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