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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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2
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Ma W, McMillen TS, Childers MC, Gong H, Regnier M, Irving T. Structural OFF/ON transitions of myosin in relaxed porcine myocardium predict calcium-activated force. Proc Natl Acad Sci U S A 2023; 120:e2207615120. [PMID: 36696446 DOI: 10.1073/pnas.2207615120] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Contraction in striated muscle is initiated by calcium binding to troponin complexes, but it is now understood that dynamic transition of myosin between resting, ordered OFF states on thick filaments and active, disordered ON states that can bind to thin filaments is critical in regulating muscle contractility. These structural OFF to ON transitions of myosin are widely assumed to correspond to transitions from the biochemically defined, energy-sparing, super-relaxed (SRX) state to the higher ATPase disordered-relaxed (DRX) state. Here we examined the effect of 2'-deoxy-ATP (dATP), a naturally occurring energy substrate for myosin, on the structural OFF to ON transitions of myosin motors in porcine cardiac muscle thick filaments. Small-angle X-ray diffraction revealed that titrating dATP in relaxation solutions progressively moves the myosin heads from ordered OFF states on the thick filament backbone to disordered ON states closer to thin filaments. Importantly, we found that the structural OFF to ON transitions are not equivalent to the biochemically defined SRX to DRX transitions and that the dATP-induced structural OFF to ON transitions of myosin motors in relaxed muscle are strongly correlated with submaximal force augmentation by dATP. These results indicate that structural OFF to ON transitions of myosin in relaxed muscle can predict the level of force attained in calcium-activated cardiac muscle. Computational modeling and stiffness measurements suggest a final step in the OFF to ON transition may involve a subset of DRX myosins that form weakly bound cross-bridges prior to becoming active force-producing cross-bridges.
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3
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Liebenberg LJP, Passmore JAS, Osman F, Jewanraj J, Mtshali A, Garcia-Lerma JG, Heneine W, Holder A, Archary D, Ngcapu S, Sivro A, Mansoor LE, Abdool Karim Q, Abdool Karim SS, McKinnon LR. Genital Immune Cell Activation and Tenofovir Gel Efficacy: A Case-Control Study. Clin Infect Dis 2022; 75:1088-1091. [PMID: 35142337 PMCID: PMC9989354 DOI: 10.1093/cid/ciac115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Indexed: 11/14/2022] Open
Abstract
Genital inflammation (GI) undermines topical human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) efficacy through unknown mechanisms. Here, associations between activated endocervical CD4 + T-cell numbers and higher deoxyadenosine triphosphate (dATP) concentrations suggest that competition for intracellular metabolites within HIV target cells may reduce the efficacy of antiretroviral-based PrEP in women with GI.
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Affiliation(s)
- Lenine J P Liebenberg
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Jo Ann S Passmore
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa.,National Health Laboratory Service, Cape Town, South Africa
| | - Farzana Osman
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Janine Jewanraj
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Andile Mtshali
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - J Gerardo Garcia-Lerma
- Division of HIV/AIDS Prevention, National Center for HIV/ AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Walid Heneine
- Division of HIV/AIDS Prevention, National Center for HIV/ AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Angela Holder
- Division of HIV/AIDS Prevention, National Center for HIV/ AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Derseree Archary
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Sinaye Ngcapu
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Aida Sivro
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa.,Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Leila E Mansoor
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa
| | - Quarraisha Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,Department of Epidemiology, Columbia University, New York, New York, USA
| | - Salim S Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,Department of Epidemiology, Columbia University, New York, New York, USA
| | - Lyle R McKinnon
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.,Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada
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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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5
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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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6
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Teichman SL, Thomson KS, Regnier M. Cardiac Myosin Activation with Gene Therapy Produces Sustained Inotropic Effects and May Treat Heart Failure with Reduced Ejection Fraction. Handb Exp Pharmacol 2017; 243:447-464. [PMID: 27590227 DOI: 10.1007/164_2016_31] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic inotropic therapy is effective for the treatment of heart failure with reduced ejection fraction, but has been limited by adverse long-term safety profiles, development of tolerance, and the need for chronic parenteral administration. A safe and convenient therapeutic agent that produces sustained inotropic effects could improve symptoms, functional capacity, and quality of life. Small amounts of 2-deoxy-adenosine triphosphate (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin crossbridge cycling with greater force generation during each contraction. This paper describes the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy to deliver and upregulate ribonucleotide reductase (R1R2), the enzyme responsible for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with a benign safety profile. Further animal studies are appropriate with the goal of testing this agent in patients with heart failure.
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Affiliation(s)
- Sam L Teichman
- BEAT Biotherapeutics Corp, 1380 112th Ave., NE, Suite 200, Seattle, WA, 98004, USA.
| | | | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA, USA.,Center for Cardiovascular Biology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
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7
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Thomson KS, Odom GL, Murry CE, Mahairas GG, Moussavi-Harami F, Teichman SL, Chen X, Hauschka SD, Chamberlain JS, Regnier M. Translation of Cardiac Myosin Activation with 2-deoxy-ATP to Treat Heart Failure via an Experimental Ribonucleotide Reductase-Based Gene Therapy. JACC Basic Transl Sci 2016; 1:666-79. [PMID: 28553667 DOI: 10.1016/j.jacbts.2016.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Despite recent advances, chronic heart failure remains a significant and growing unmet medical need, reaching epidemic proportions carrying substantial morbidity, mortality, and costs. A safe and convenient therapeutic agent that produces sustained inotropic effects could ameliorate symptoms and improve functional capacity and quality of life. The authors discovered that small amounts of 2-deoxy-ATP (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin cross-bridge cycling with greater force generation during each contraction. They describe the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy that up-regulates ribonucleotide reductase, the rate-limiting enzyme for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with no toxicity or safety concerns identified to date. Further animal studies are being conducted with the goal of testing this agent in patients with heart failure.
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8
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Welbourn S, Strebel K. Low dNTP levels are necessary but may not be sufficient for lentiviral restriction by SAMHD1. Virology 2015; 488:271-7. [PMID: 26655245 DOI: 10.1016/j.virol.2015.11.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 11/19/2015] [Accepted: 11/20/2015] [Indexed: 12/14/2022]
Abstract
SAMHD1 is a cellular dNTPase that restricts lentiviral infection presumably by lowering cellular dNTP levels to below a critical threshold required for reverse transcription; however, lowering cellular dNTP levels may not be the sole mechanism of restriction. In particular, an exonuclease activity of SAMHD1 was reported to contribute to virus restriction. We further investigated the requirements for SAMHD1 restriction activity in both differentiated U937 and cycling HeLa cells. Using hydroxyurea treatment to lower baseline dNTP levels in HeLa cells, we were able to document efficient SAMHD1 restriction without significant further reduction in dNTP levels by SAMHD1. These results argue against a requirement for additional myeloid-specific host factors for SAMHD1 function but further support the notion that SAMHD1 possesses an additional dNTP-independent function contributing to lentiviral restriction. However, our own experiments failed to associate this presumed additional SAMHD1 antiviral activity with a reported nuclease activity.
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Affiliation(s)
- Sarah Welbourn
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, NIH, Building 4, Room 310, 4 Center Drive, MSC 0460, Bethesda, MD 20892-0460, USA
| | - Klaus Strebel
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, NIH, Building 4, Room 310, 4 Center Drive, MSC 0460, Bethesda, MD 20892-0460, USA.
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9
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Lundy SD, Murphy SA, Dupras SK, Dai J, Murry CE, Laflamme MA, Regnier M. Cell-based delivery of dATP via gap junctions enhances cardiac contractility. J Mol Cell Cardiol 2014; 72:350-9. [PMID: 24780238 DOI: 10.1016/j.yjmcc.2014.04.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 04/15/2014] [Accepted: 04/17/2014] [Indexed: 11/18/2022]
Abstract
The transplantation of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is a promising strategy to treat myocardial infarction and reverse heart failure, but to date the contractile benefit in most studies remains modest. We have previously shown that the nucleotide 2-deoxyadenosine triphosphate (dATP) can substitute for ATP as the energy substrate for cardiac myosin, and increasing cellular dATP content by globally overexpressing ribonucleotide reductase (R1R2) can dramatically enhance cardiac contractility. Because dATP is a small molecule, we hypothesized that it would diffuse readily between cells via gap junctions and enhance the contractility of neighboring coupled wild type cells. To test this hypothesis, we performed studies with the goals of (1) validating gap junction-mediated dATP transfer in vitro and (2) investigating the use of R1R2-overexpressing hPSC-CMs in vivo as a novel strategy to increase cardiac function. We first performed intracellular dye transfer studies using dATP conjugated to fluorescein and demonstrated rapid gap junction-mediated transfer between cardiomyocytes. We then cocultured wild type cardiomyocytes with either cardiomyocytes or fibroblasts overexpressing R1R2 and saw more than a twofold increase in the extent and rate of contraction of wild type cardiomyocytes. Finally, we transplanted hPSC-CMs overexpressing R1R2 into healthy uninjured rat hearts and noted an increase in fractional shortening from 41±4% to 53±5% just five days after cell transplantation. These findings demonstrate that dATP is an inotropic factor that spreads between cells via gap junctions. Our data suggest that transplantation of dATP-producing hPSC-CMs could significantly increase the effectiveness of cardiac cell therapy.
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Affiliation(s)
- Scott D Lundy
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA
| | - Sean A Murphy
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Sarah K Dupras
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98195, USA
| | - Jin Dai
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Charles E Murry
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98195, USA; Department of Pathology, University of Washington, Seattle, WA 98195, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98195, USA
| | - Michael A Laflamme
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98195, USA; Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98195, USA.
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10
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Ahn YK, Tripathi S, Kim JH, Cho YI, Lee HE, Kim DS, Woo JG, Cho MC. Transcriptome analysis of Capsicum annuum varieties Mandarin and Blackcluster: assembly, annotation and molecular marker discovery. Gene 2014; 533:494-9. [PMID: 24125952 DOI: 10.1016/j.gene.2013.09.095] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 09/26/2013] [Indexed: 11/22/2022]
Abstract
Next generation sequencing technologies have proven to be a rapid and cost-effective means to assemble and characterize gene content and identify molecular markers in various organisms. Pepper (Capsicum annuum L., Solanaceae) is a major staple vegetable crop, which is economically important and has worldwide distribution. High-throughput transcriptome profiling of two pepper cultivars, Mandarin and Blackcluster, using 454 GS-FLX pyrosequencing yielded 279,221 and 316,357 sequenced reads with a total 120.44 and 142.54Mb of sequence data (average read length of 431 and 450 nucleotides). These reads resulted from 17,525 and 16,341 'isogroups' and were assembled into 19,388 and 18,057 isotigs, and 22,217 and 13,153 singletons for both the cultivars, respectively. Assembled sequences were annotated functionally based on homology to genes in multiple public databases. Detailed sequence variant analysis identified a total of 9701 and 12,741 potential SNPs which eventually resulted in 1025 and 1059 genotype specific SNPs, for both the varieties, respectively, after examining SNP frequency distribution for each mapped unigenes. These markers for pepper will be highly valuable for marker-assisted breeding and other genetic studies.
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11
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Haas M, Ben-Moshe I, Fischer B, Reiser G. Sp-2-propylthio-ATP-α-B and Sp-2-propylthio-ATP-α-B,β-γ-dichloromethylene are novel potent and specific agonists of the human P2Y₁₁ receptor. Biochem Pharmacol 2013; 86:645-55. [PMID: 23810430 DOI: 10.1016/j.bcp.2013.06.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 06/13/2013] [Accepted: 06/14/2013] [Indexed: 11/28/2022]
Abstract
The human P2Y₁₁ nucleotide receptor mRNA was found in virtually all human tissues, and the receptor serves many physiological roles, such as immune response regulation. The Ala-87-Thr-P2Y₁₁ receptor single nucleotide polymorphism was linked to increased risk for acute myocardial infarction. To facilitate the development of new therapeutic applications involving cells expressing several P2 receptor subtypes, the availability of specific and potent agonists is mandatory. Here, we synthesized a series of novel adenine nucleotide derivatives, based upon the potent P2Y₁₁ receptor agonists AR-C67085. Features of the novel nucleotide derivatives are a propylthio substitution at C2-adenine and a Pα-borano or Pα-thio substitution of non-bridging oxygen atom. The latter substitutions introduce a chiral center at the α-phosphate. Sp-isomers of Pα-borano- and Rp-isomers of Pα-thio-substituted nucleotides are preferred by the P2Y₁₁ receptor. As recently reported by us, diastereoselectivity of the P2Y₁₁ receptor is opposite to that of the P2Y₁ receptor. Therefore, we exploit this characteristic to increase nucleotide selectivity. At the P2Y₁₁ receptor, the Sp-isomers of 2-propylthio-ATP-α-B (2B) and 2-propylthio-ATP-α-B,β-γ-dichloromethylene (4B) were the most potent of the novel nucleotide series, with EC₅₀ values of 0.03 μM for both, being ca. 80-fold more potent than 2-propylthio-ATP and ATP (EC₅₀ = 2.6 μM). We conclude that the borano-substitution at the α-phosphate of 2-propylthio-ATP enhances nucleotide potency at the P2Y₁₁ receptor. The combination with a Pβ-Pγ-dichloromethylene group in 4B results in a nucleotide, which shows higher selectivity for the P2Y₁₁ receptor over the P2Y₁₁ receptor than 2B making it the most promising of the novel P2Y₁₁ receptor agonists.
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Affiliation(s)
- Michael Haas
- Institute for Neurobiochemistry, Faculty of Medicine, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
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