1
|
Purhonen J, Banerjee R, McDonald AE, Fellman V, Kallijärvi J. A sensitive assay for dNTPs based on long synthetic oligonucleotides, EvaGreen dye and inhibitor-resistant high-fidelity DNA polymerase. Nucleic Acids Res 2020; 48:e87. [PMID: 32573728 PMCID: PMC7470940 DOI: 10.1093/nar/gkaa516] [Citation(s) in RCA: 283] [Impact Index Per Article: 70.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 12/15/2022] Open
Abstract
Deoxyribonucleoside triphosphates (dNTPs) are vital for the biosynthesis and repair of DNA. Their cellular concentration peaks during the S phase of the cell cycle. In non-proliferating cells, dNTP concentrations are low, making their reliable quantification from tissue samples of heterogeneous cellular composition challenging. Partly because of this, the current knowledge related to the regulation of and disturbances in cellular dNTP concentrations derive mostly from cell culture experiments with little corroboration at the tissue or organismal level. Here, we fill the methodological gap by presenting a simple non-radioactive microplate assay for the quantification of dNTPs with a minimum requirement of 4-12 mg of biopsy material. In contrast to published assays, this assay is based on long synthetic single-stranded DNA templates (50-200 nucleotides), an inhibitor-resistant high-fidelity DNA polymerase, and the double-stranded-DNA-binding EvaGreen dye. The assay quantified reliably less than 50 fmol of each of the four dNTPs and discriminated well against ribonucleotides. Additionally, thermostable RNAse HII-mediated nicking of the reaction products and a subsequent shift in their melting temperature allowed near-complete elimination of the interfering ribonucleotide signal, if present. Importantly, the assay allowed measurement of minute dNTP concentrations in mouse liver, heart and skeletal muscle.
Collapse
Affiliation(s)
- Janne Purhonen
- Folkhälsan Research Center, Helsinki, Finland.,Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
| | - Rishi Banerjee
- Folkhälsan Research Center, Helsinki, Finland.,Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
| | | | - Vineta Fellman
- Folkhälsan Research Center, Helsinki, Finland.,Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland.,Department of Clinical Sciences, Lund, Pediatrics, Lund University, Sweden.,Children's Hospital, Helsinki University Hospital, Finland
| | - Jukka Kallijärvi
- Folkhälsan Research Center, Helsinki, Finland.,Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
| |
Collapse
|
2
|
Teichman SL, Thomson KS, Regnier M. Cardiac Myosin Activation with Gene Therapy Produces Sustained Inotropic Effects and May Treat Heart Failure with Reduced Ejection Fraction. Handb Exp Pharmacol 2017; 243:447-464. [PMID: 27590227 DOI: 10.1007/164_2016_31] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic inotropic therapy is effective for the treatment of heart failure with reduced ejection fraction, but has been limited by adverse long-term safety profiles, development of tolerance, and the need for chronic parenteral administration. A safe and convenient therapeutic agent that produces sustained inotropic effects could improve symptoms, functional capacity, and quality of life. Small amounts of 2-deoxy-adenosine triphosphate (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin crossbridge cycling with greater force generation during each contraction. This paper describes the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy to deliver and upregulate ribonucleotide reductase (R1R2), the enzyme responsible for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with a benign safety profile. Further animal studies are appropriate with the goal of testing this agent in patients with heart failure.
Collapse
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
| |
Collapse
|
3
|
Translation of Cardiac Myosin Activation with 2-deoxy-ATP to Treat Heart Failure via an Experimental Ribonucleotide Reductase-Based Gene Therapy. JACC Basic Transl Sci 2016; 1:666-679. [PMID: 28553667 PMCID: PMC5444879 DOI: 10.1016/j.jacbts.2016.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Despite recent advances, chronic heart failure remains a significant and growing unmet medical need, reaching epidemic proportions carrying substantial morbidity, mortality, and costs. A safe and convenient therapeutic agent that produces sustained inotropic effects could ameliorate symptoms and improve functional capacity and quality of life. The authors discovered that small amounts of 2-deoxy-ATP (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin cross-bridge cycling with greater force generation during each contraction. They describe the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy that up-regulates ribonucleotide reductase, the rate-limiting enzyme for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with no toxicity or safety concerns identified to date. Further animal studies are being conducted with the goal of testing this agent in patients with heart failure.
Collapse
|
4
|
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 PMCID: PMC4073675 DOI: 10.1016/j.yjmcc.2014.04.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [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.
Collapse
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.
| |
Collapse
|
5
|
Nuclear tropomyosin and troponin in striated muscle: new roles in a new locale? J Muscle Res Cell Motil 2013; 34:275-84. [DOI: 10.1007/s10974-013-9356-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 07/23/2013] [Indexed: 01/03/2023]
|
6
|
Nowakowski SG, Kolwicz SC, Korte FS, Luo Z, Robinson-Hamm JN, Page JL, Brozovich F, Weiss RS, Tian R, Murry CE, Regnier M. Transgenic overexpression of ribonucleotide reductase improves cardiac performance. Proc Natl Acad Sci U S A 2013; 110:6187-92. [PMID: 23530224 PMCID: PMC3625337 DOI: 10.1073/pnas.1220693110] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We previously demonstrated that cardiac myosin can use 2-deoxy-ATP (dATP) as an energy substrate, that it enhances contraction and relaxation with minimal effect on calcium-handling properties in vitro, and that contractile enhancement occurs with only minor elevation of cellular [dATP]. Here, we report the effect of chronically enhanced dATP concentration on cardiac function using a transgenic mouse that overexpresses the enzyme ribonucleotide reductase (TgRR), which catalyzes the rate-limiting step in de novo deoxyribonucleotide biosynthesis. Hearts from TgRR mice had elevated left ventricular systolic function compared with wild-type (WT) mice, both in vivo and in vitro, without signs of hypertrophy or altered diastolic function. Isolated cardiomyocytes from TgRR mice had enhanced contraction and relaxation, with no change in Ca(2+) transients, suggesting targeted improvement of myofilament function. TgRR hearts had normal ATP and only slightly decreased phosphocreatine levels by (31)P NMR spectroscopy, and they maintained rate responsiveness to dobutamine challenge. These data demonstrate long-term (at least 5-mo) elevation of cardiac [dATP] results in sustained elevation of basal left ventricular performance, with maintained β-adrenergic responsiveness and energetic reserves. Combined with results from previous studies, we conclude that this occurs primarily via enhanced myofilament activation and contraction, with similar or faster ability to relax. The data are sufficiently compelling to consider elevated cardiac [dATP] as a therapeutic option to treat systolic dysfunction.
Collapse
Affiliation(s)
| | - Stephen C. Kolwicz
- Mitochondria and Metabolism Center, University of Washington School of Medicine, Seattle, WA 98195
| | - Frederick Steven Korte
- Department of Bioengineering, University of Washington, Seattle, WA 98195
- Center for Cardiovascular Biology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195
| | - Zhaoxiong Luo
- Department of Bioengineering, University of Washington, Seattle, WA 98195
| | | | - Jennifer L. Page
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853
| | | | - Robert S. Weiss
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853
| | - Rong Tian
- Mitochondria and Metabolism Center, University of Washington School of Medicine, Seattle, WA 98195
| | - Charles E. Murry
- Department of Bioengineering, University of Washington, Seattle, WA 98195
- Center for Cardiovascular Biology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195
- Department of Pathology, University of Washington, Seattle, WA 98195; and
- Department of Medicine/Cardiology, University of Washington, Seattle, WA 98195
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98195
- Center for Cardiovascular Biology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195
| |
Collapse
|
7
|
Baker AJ. Refueling the heart: Using 2-deoxy-ATP to enhance cardiac contractility. J Mol Cell Cardiol 2011; 51:883-4. [PMID: 22001677 DOI: 10.1016/j.yjmcc.2011.09.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 09/29/2011] [Indexed: 11/25/2022]
|
8
|
Upregulation of cardiomyocyte ribonucleotide reductase increases intracellular 2 deoxy-ATP, contractility, and relaxation. J Mol Cell Cardiol 2011; 51:894-901. [PMID: 21925507 PMCID: PMC3208740 DOI: 10.1016/j.yjmcc.2011.08.026] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 08/22/2011] [Accepted: 08/25/2011] [Indexed: 11/22/2022]
Abstract
We have previously demonstrated that substitution of ATP with 2 deoxy-ATP
(dATP) increased the magnitude and rate of force production at all levels of
Ca2+-mediated activation in demembranated cardiac muscle.
In the current study we hypothesized that cellular [dATP] could
be increased by viral-mediated over expression of the ribonucleotide reductase
(Rrm1 and Rrm2) complex, which would increase contractility of adult rat
cardiomyocytes. Cell length and ratiometric (fura2) Ca2+
fluorescence were monitored by video microscopy. At 0.5 Hz stimulation, the
extent of shortening was increased ~40% and maximal rate of shortening
was increased ~80% in cardiomyocytes overexpressing Rrm1+Rrm2 as
compared to non-transduced cardiomyocytes. The maximal rate of relaxation was
also increased ~150% with Rrm1+Rrm2 over expression, resulting
in decreased time to 50% relaxation over non-transduced cardiomyocytes.
These differences were even more dramatic when compared to cardiomyocytes
expressing GFP-only. Interestingly, Rrm1+Rrm2 over expression had no
effect on minimal or maximal intracellular
[Ca2+] (Fura2 fluorescence), indicating
increased contractility is primarily due to increased myofilament activity
without altering Ca2+ release from the sarcoplasmic
reticulum. Additionally, functional potentiation was maintained with
Rrm1+Rrm2 over expression as stimulation frequency was increased (1 Hz
and 2 Hz). HPLC analysis indicated cellular [dATP] was increased
by approximately 10-fold following transduction, becoming ~1.5% of the
adenine nucleotide pool. Furthermore, 2% dATP was sufficient to
significantly increase crossbridge binding and contractile force during
sub-maximal Ca2+ activation in demembranated cardiac muscle.
These experiments demonstrate the feasibility of directly targeting the
actin-myosin chemomechanical crossbridge cycle to enhance cardiac contractility
and relaxation without affecting minimal or maximal Ca2+.
Collapse
|
9
|
Trastuzumab versus lapatinib: the cardiac side of the story. Cancer Treat Rev 2009; 35:633-8. [PMID: 19640652 DOI: 10.1016/j.ctrv.2009.06.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Revised: 06/15/2009] [Accepted: 06/22/2009] [Indexed: 11/21/2022]
Abstract
HER2 gene plays a pivotal role in the pathogenesis of 20% of breast cancer patients. At the same time, it is one of the main cardiac survival pathways when subjected to bio-mechanical stress including exposure to anthracyclines. With the emergence of the anti-HER2 targeting agents, concerns raised regarding the potential cardiac toxicities of these drugs. In the early clinical trials with trastuzumab, it was evident that it has a significant cardiac toxicity. The incidence of symptomatic heart failure ranged from 4% to 7% with trastuzumab alone, and 27% when administered concurrently with doxorubicin. On the other hand, available data suggest that lapatinib is much less cardiotoxic. The incidence of symptomatic heart failure has been constantly reported to be less than 0.5%. In this review, we discuss the possible theories behind the differences in the cardiac profile of both agents. We emphasize on the role of cardiac bioenergetics and the effects of trastuzumab and lapatinib on ATP production through the different effects they exert on the cardiac mitochondria.
Collapse
|