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Hamaguchi S, Agata N, Seki M, Namekata I, Tanaka H. Developmental Changes in the Excitation-Contraction Mechanisms of the Ventricular Myocardium and Their Sympathetic Regulation in Small Experimental Animals. J Cardiovasc Dev Dis 2024; 11:267. [PMID: 39330325 PMCID: PMC11432613 DOI: 10.3390/jcdd11090267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 08/02/2024] [Accepted: 08/11/2024] [Indexed: 09/28/2024] Open
Abstract
The developmental changes in the excitation-contraction mechanisms of the ventricular myocardium of small animals (guinea pig, rat, mouse) and their sympathetic regulation will be summarized. The action potential duration monotonically decreases during pre- and postnatal development in the rat and mouse, while in the guinea pig it decreases during the fetal stage but turns into an increase just before birth. Such changes can be attributed to changes in the repolarizing potassium currents. The T-tubule and the sarcoplasmic reticulum are scarcely present in the fetal cardiomyocyte, but increase during postnatal development. This causes a developmental shift in the Ca2+ handling from a sarcolemma-dependent mechanism to a sarcoplasmic reticulum-dependent mechanism. The sensitivity for beta-adrenoceptor-mediated positive inotropy decreases during early postnatal development, which parallels the increase in sympathetic nerve innervation. The alpha-adrenoceptor-mediated inotropy in the mouse changes from positive in the neonate to negative in the adult. This can be explained by the change in the excitation-contraction mechanism mentioned above. The shortening of the action potential duration enhances trans-sarcolemmal Ca2+ extrusion by the Na+-Ca2+ exchanger. The sarcoplasmic reticulum-dependent mechanism of contraction in the adult allows Na+-Ca2+ exchanger activity to cause negative inotropy, a mechanism not observed in neonatal myocardium. Such developmental studies would provide clues towards a more comprehensive understanding of cardiac function.
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Affiliation(s)
| | | | | | | | - Hikaru Tanaka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi 274-8510, Japan; (S.H.); (N.A.); (M.S.); (I.N.)
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2
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Maniezzi C, Eskandr M, Florindi C, Ferrandi M, Barassi P, Sacco E, Pasquale V, Maione AS, Pompilio G, Teixeira VON, de Boer RA, Silljé HHW, Lodola F, Zaza A. Early consequences of the phospholamban mutation PLN-R14del +/- in a transgenic mouse model. Acta Physiol (Oxf) 2024; 240:e14082. [PMID: 38214033 DOI: 10.1111/apha.14082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 12/11/2023] [Accepted: 01/01/2024] [Indexed: 01/13/2024]
Abstract
AIMS The heterozygous phospholamban (PLN) mutation R14del (PLN R14del+/- ) is associated with a severe arrhythmogenic cardiomyopathy (ACM) developing in the adult. "Superinhibition" of SERCA2a by PLN R14del is widely assumed to underlie the pathogenesis, but alternative mechanisms such abnormal energy metabolism have also been reported. This work aims to (1) to evaluate Ca2+ dynamics and energy metabolism in a transgenic (TG) mouse model of the mutation prior to cardiomyopathy development; (2) to test whether they are causally connected. METHODS Ca2+ dynamics, energy metabolism parameters, reporters of mitochondrial integrity, energy, and redox homeostasis were measured in ventricular myocytes of 8-12 weeks-old, phenotypically silent, TG mice. Mutation effects were compared to pharmacological PLN antagonism and analyzed during modulation of sarcoplasmic reticulum (SR) and cytosolic Ca2+ compartments. Transcripts and proteins of relevant signaling pathways were evaluated. RESULTS The mutation was characterized by hyperdynamic Ca2+ handling, compatible with a loss of SERCA2a inhibition by PLN. All components of energy metabolism were depressed; myocyte energy charge was preserved under quiescence but reduced during stimulation. Cytosolic Ca2+ buffering or SERCA2a blockade reduced O2 consumption with larger effect in the mutant. Signaling changes suggest cellular adaptation to perturbed Ca2+ dynamics and response to stress. CONCLUSIONS (1) PLN R14del+/- loses its ability to inhibit SERCA2a, which argues against SERCA2a superinhibition as a pathogenetic mechanism; (2) depressed energy metabolism, its enhanced dependency on Ca2+ and activation of signaling responses point to an early involvement of metabolic stress in the pathogenesis of this ACM model.
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Affiliation(s)
- Claudia Maniezzi
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Marem Eskandr
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Chiara Florindi
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Mara Ferrandi
- Windtree Therapeutics Inc., Warrington, Pennsylvania, USA
| | - Paolo Barassi
- Windtree Therapeutics Inc., Warrington, Pennsylvania, USA
| | - Elena Sacco
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Valentina Pasquale
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Angela S Maione
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino IRCCS, Milan, Italy
| | - Giulio Pompilio
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino IRCCS, Milan, Italy
- Department of Biomedical, Surgical and Dentist Sciences, University of Milano, Milan, Italy
| | | | - Rudolf A de Boer
- Department of Cardiology, Erasmus University Medical Center, University of Rotterdam, Rotterdam, Netherlands
| | - Herman H W Silljé
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Francesco Lodola
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Antonio Zaza
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
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Arici M, Hsu SC, Ferrandi M, Barassi P, Ronchi C, Torre E, Luraghi A, Chang GJ, Ferrari P, Bianchi G, Peri F, Zaza A, Rocchetti M. Selective SERCA2a activator as a candidate for chronic heart failure therapy. J Transl Med 2024; 22:77. [PMID: 38243248 PMCID: PMC10797746 DOI: 10.1186/s12967-024-04874-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/08/2024] [Indexed: 01/21/2024] Open
Abstract
BACKGROUND The sarcoplasmic reticulum (SR) Ca2+ ATPase (SERCA2a) depression substantially contributes to diastolic dysfunction in heart failure (HF), suggesting that SERCA2a stimulation may be a mechanism-based HF therapy. Istaroxime is a drug endowed with both a SERCA2a stimulatory activity and a Na+/K+ pump inhibitory activity for acute HF treatment. Its main metabolite PST3093 shows a more favorable therapeutic profile as compared to the parent drug, but it is still unsuitable for chronic usage. Novel PST3093 derivatives have been recently developed for oral (chronic) HF treatment; compound 8 was selected among them and here characterized. METHODS Effects of compound 8 were evaluated in a context of SERCA2a depression, by using streptozotocin-treated rats, a well-known model of diastolic dysfunction. The impact of SERCA2a stimulation by compound 8 was assessed at the cellular level ad in vivo, following i.v. infusion (acute effects) or oral administration (chronic effects). RESULTS As expected from SERCA2a stimulation, compound 8 induced SR Ca2+ compartmentalization in STZ myocytes. In-vivo echocardiographic analysis during i.v. infusion and after repeated oral administration of compound 8, detected a significant improvement of diastolic function. Moreover, compound 8 did not affect electrical activity of healthy guinea-pig myocytes, in line with the absence of off-target effects. Finally, compound 8 was well tolerated in mice with no evidence of acute toxicity. CONCLUSIONS The pharmacological evaluation of compound 8 indicates that it may be a safe and selective drug for a mechanism-based treatment of chronic HF by restoring SERCA2a activity.
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Affiliation(s)
- Martina Arici
- Department of Biotechnology and Biosciences, Università Degli Studi di Milano-Bicocca, P.Za Della Scienza 2, 20126, Milan, Italy
| | - Shih-Che Hsu
- CVie Therapeutics Limited, Taipei, 11047, Taiwan
| | - Mara Ferrandi
- Windtree Therapeutics Inc, Warrington, PA, 18976, USA
| | - Paolo Barassi
- Windtree Therapeutics Inc, Warrington, PA, 18976, USA
| | - Carlotta Ronchi
- Department of Biotechnology and Biosciences, Università Degli Studi di Milano-Bicocca, P.Za Della Scienza 2, 20126, Milan, Italy
| | - Eleonora Torre
- Department of Biotechnology and Biosciences, Università Degli Studi di Milano-Bicocca, P.Za Della Scienza 2, 20126, Milan, Italy
| | - Andrea Luraghi
- Department of Biotechnology and Biosciences, Università Degli Studi di Milano-Bicocca, P.Za Della Scienza 2, 20126, Milan, Italy
| | | | | | - Giuseppe Bianchi
- Windtree Therapeutics Inc, Warrington, PA, 18976, USA
- Università Vita-Salute San Raffaele, 20132, Milan, Italy
| | - Francesco Peri
- Department of Biotechnology and Biosciences, Università Degli Studi di Milano-Bicocca, P.Za Della Scienza 2, 20126, Milan, Italy
| | - Antonio Zaza
- Department of Biotechnology and Biosciences, Università Degli Studi di Milano-Bicocca, P.Za Della Scienza 2, 20126, Milan, Italy.
| | - Marcella Rocchetti
- Department of Biotechnology and Biosciences, Università Degli Studi di Milano-Bicocca, P.Za Della Scienza 2, 20126, Milan, Italy.
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Fairuz S, Ang CW, Mraiche F, Goh JK. Current Targets and Future Directions of Positive Inotropes for Heart Failure. Curr Med Chem 2024; 31:6971-6991. [PMID: 37909442 DOI: 10.2174/0109298673262360231018193823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/23/2023] [Accepted: 09/11/2023] [Indexed: 11/03/2023]
Abstract
While a congestive heart failure patient will ultimately need an assist device or even a replacement heart as the disease progresses, not every patient is qualified for such advanced therapy. Such patients awaiting better circulatory support benefit from positive inotropes in the meantime as palliative care. These agents are often prescribed in patients with acute decompensated heart failure, with reduced left ventricular ejection fraction and symptoms of organ dysfunction. Although positive inotropes, for example, digoxin, dobutamine, milrinone, levosimendan, etc., are successfully marketed and in use, a lot of their adverse effects, like arrhythmias, hypotension, and even sudden cardiac death, are rather encouraging further research on the development of novel positive inotropes. This review has investigated the molecular mechanisms of some of these adverse effects in terms of the proteins they target, followed by research on newer targets. Studies from 2013-2023 that have reported new small molecules with positive inotropic effects have been revisited in order to determine the progress made so far in drug discovery.
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Affiliation(s)
- Shadreen Fairuz
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia
| | - Chee Wei Ang
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia
| | - Fatima Mraiche
- Department of Pharmacology, University of Alberta, 116 St & 85 Ave, Edmonton, ABT6G 2R3, Canada
| | - Joo Kheng Goh
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia
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Newbury D, Frishman W. Istaroxime: A Novel Therapeutic Agent for Acute Heart Failure. Cardiol Rev 2023:00045415-990000000-00145. [PMID: 37811998 DOI: 10.1097/crd.0000000000000598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Acute decompensated heart failure (ADHF) is a multifactorial process that is associated with high morbidity and mortality. Treatment with inotropes can rapidly improve hemodynamic status; however, their use has been associated with increased mortality and incidence of arrhythmias. Istaroxime is a first-in-class intravenous agent currently undergoing clinical trials for acute heart failure. It has the unique mechanism of action of both Na+/K+ ATPase inhibition and sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a stimulation. Notably, its action on sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a improves calcium handling, which is known to be abnormal in heart failure. Clinical trials have shown that istaroxime has beneficial hemodynamic effects; in particular, its ability to increase systolic blood pressure without causing significant increases in heart rate or clinically significant arrhythmias differentiates it from inotropes currently utilized for ADHF treatment, such as milrinone. While initial studies are encouraging, additional trials are needed to assess outcomes and to compare their performance to standard inotropes in patients hospitalized with ADHF. This article will review the relevant preclinical and clinical trials for istaroxime, as well as the relevant pharmacology.
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Affiliation(s)
- Danielle Newbury
- From the Department of Medicine, New York-Presbyterian/Weill Cornell Medical Center, New York, NY
| | - William Frishman
- Departments of Medicine and Cardiology, New York Medical College/Westchester Medical Center, Valhalla, NY
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Moccia F, Fiorio Pla A, Lim D, Lodola F, Gerbino A. Intracellular Ca 2+ signalling: unexpected new roles for the usual suspect. Front Physiol 2023; 14:1210085. [PMID: 37576340 PMCID: PMC10413985 DOI: 10.3389/fphys.2023.1210085] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/18/2023] [Indexed: 08/15/2023] Open
Abstract
Cytosolic Ca2+ signals are organized in complex spatial and temporal patterns that underlie their unique ability to regulate multiple cellular functions. Changes in intracellular Ca2+ concentration ([Ca2+]i) are finely tuned by the concerted interaction of membrane receptors and ion channels that introduce Ca2+ into the cytosol, Ca2+-dependent sensors and effectors that translate the elevation in [Ca2+]i into a biological output, and Ca2+-clearing mechanisms that return the [Ca2+]i to pre-stimulation levels and prevent cytotoxic Ca2+ overload. The assortment of the Ca2+ handling machinery varies among different cell types to generate intracellular Ca2+ signals that are selectively tailored to subserve specific functions. The advent of novel high-speed, 2D and 3D time-lapse imaging techniques, single-wavelength and genetic Ca2+ indicators, as well as the development of novel genetic engineering tools to manipulate single cells and whole animals, has shed novel light on the regulation of cellular activity by the Ca2+ handling machinery. A symposium organized within the framework of the 72nd Annual Meeting of the Italian Society of Physiology, held in Bari on 14-16th September 2022, has recently addressed many of the unexpected mechanisms whereby intracellular Ca2+ signalling regulates cellular fate in healthy and disease states. Herein, we present a report of this symposium, in which the following emerging topics were discussed: 1) Regulation of water reabsorption in the kidney by lysosomal Ca2+ release through Transient Receptor Potential Mucolipin 1 (TRPML1); 2) Endoplasmic reticulum-to-mitochondria Ca2+ transfer in Alzheimer's disease-related astroglial dysfunction; 3) The non-canonical role of TRP Melastatin 8 (TRPM8) as a Rap1A inhibitor in the definition of some cancer hallmarks; and 4) Non-genetic optical stimulation of Ca2+ signals in the cardiovascular system.
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Affiliation(s)
- Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Pavia, Italy
| | | | - Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale “Amedeo Avogadro”, Novara, Italy
| | - Francesco Lodola
- Department of Biotechnology and Biosciences, University of Milan-Bicocca, Milan, Italy
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Milan, Italy
| | - Andrea Gerbino
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, Bari, Italy
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Kho C. Targeting calcium regulators as therapy for heart failure: focus on the sarcoplasmic reticulum Ca-ATPase pump. Front Cardiovasc Med 2023; 10:1185261. [PMID: 37534277 PMCID: PMC10392702 DOI: 10.3389/fcvm.2023.1185261] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 07/06/2023] [Indexed: 08/04/2023] Open
Abstract
Impaired myocardial Ca2+ cycling is a critical contributor to the development of heart failure (HF), causing changes in the contractile function and structure remodeling of the heart. Within cardiomyocytes, the regulation of sarcoplasmic reticulum (SR) Ca2+ storage and release is largely dependent on Ca2+ handling proteins, such as the SR Ca2+ ATPase (SERCA2a) pump. During the relaxation phase of the cardiac cycle (diastole), SERCA2a plays a critical role in transporting cytosolic Ca2+ back to the SR, which helps to restore both cytosolic Ca2+ levels to their resting state and SR Ca2+ content for the next contraction. However, decreased SERCA2a expression and/or pump activity are key features in HF. As a result, there is a growing interest in developing therapeutic approaches to target SERCA2a. This review provides an overview of the regulatory mechanisms of the SERCA2a pump and explores potential strategies for SERCA2a-targeted therapy, which are being investigated in both preclinical and clinical studies.
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Affiliation(s)
- Changwon Kho
- Division of Applied Medicine, School of Korean Medicine, Pusan National University, Yangsan, Republic of Korea
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8
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Roopnarine O, Yuen SL, Thompson AR, Roelike LN, Rebbeck RT, Bidwell PA, Aldrich CC, Cornea RL, Thomas DD. Fluorescence lifetime FRET assay for live-cell high-throughput screening of the cardiac SERCA pump yields multiple classes of small-molecule allosteric modulators. Sci Rep 2023; 13:10673. [PMID: 37393380 PMCID: PMC10314922 DOI: 10.1038/s41598-023-37704-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 06/26/2023] [Indexed: 07/03/2023] Open
Abstract
We have used FRET-based biosensors in live cells, in a robust high-throughput screening (HTS) platform, to identify small-molecules that alter the structure and activity of the cardiac sarco/endoplasmic reticulum calcium ATPase (SERCA2a). Our primary aim is to discover drug-like small-molecule activators that improve SERCA's function for the treatment of heart failure. We have previously demonstrated the use of an intramolecular FRET biosensor, based on human SERCA2a, by screening two different small validation libraries using novel microplate readers that detect the fluorescence lifetime or emission spectrum with high speed, precision, and resolution. Here we report results from FRET-HTS of 50,000 compounds using the same biosensor, with hit compounds functionally evaluated using assays for Ca2+-ATPase activity and Ca2+-transport. We focused on 18 hit compounds, from which we identified eight structurally unique scaffolds and four scaffold classes as SERCA modulators, approximately half of which are activators and half are inhibitors. Five of these compounds were identified as promising SERCA activators, one of which activates Ca2+-transport even more than Ca2+-ATPase activity thus improving SERCA efficiency. While both activators and inhibitors have therapeutic potential, the activators establish the basis for future testing in heart disease models and lead development, toward pharmaceutical therapy for heart failure.
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Affiliation(s)
- Osha Roopnarine
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
| | - Samantha L Yuen
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Andrew R Thompson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Lauren N Roelike
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Robyn T Rebbeck
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Philip A Bidwell
- Department of Medicine, Cardiovascular Division, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
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9
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Roopnarine O, Yuen SL, Thompson AR, Roelike LN, Rebbeck RT, Bidwell PA, Aldrich CC, Cornea RL, Thomas DD. FRET assay for live-cell high-throughput screening of the cardiac SERCA pump yields multiple classes of small-molecule allosteric modulators. RESEARCH SQUARE 2023:rs.3.rs-2596384. [PMID: 36909610 PMCID: PMC10002828 DOI: 10.21203/rs.3.rs-2596384/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
We have used FRET-based biosensors in live cells, in a robust high-throughput screening (HTS) platform, to identify small-molecules that alter the structure and activity of the cardiac sarco/endoplasmic reticulum calcium ATPase (SERCA2a). Our primary aim is to discover drug-like small-molecule activators that improve SERCA’s function for the treatment of heart failure. We have previously demonstrated the use of an intramolecular FRET biosensor, based on human SERCA2a, by screening a small validation library using novel microplate readers that can detect the fluorescence lifetime or emission spectrum with high speed, precision, and resolution. Here we report results from a 50,000-compound screen using the same biosensor, with hit compounds functionally evaluated using Ca 2+ -ATPase and Ca 2+ -transport assays. We focused on 18 hit compounds, from which we identified eight structurally unique compounds and four compound classes as SERCA modulators, approximately half of which are activators and half are inhibitors. While both activators and inhibitors have therapeutic potential, the activators establish the basis for future testing in heart disease models and lead development, toward pharmaceutical therapy for heart failure.
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10
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Roopnarine O, Yuen SL, Thompson AR, Roelike LN, Rebbeck RT, Bidwell PA, Aldrich CC, Cornea RL, Thomas DD. FRET assay for live-cell high-throughput screening of the cardiac SERCA pump yields multiple classes of small-molecule allosteric modulators. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.22.529557. [PMID: 36865289 PMCID: PMC9980093 DOI: 10.1101/2023.02.22.529557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
We have used FRET-based biosensors in live cells, in a robust high-throughput screening (HTS) platform, to identify small-molecules that alter the structure and activity of the cardiac sarco/endoplasmic reticulum calcium ATPase (SERCA2a). Our primary aim is to discover drug-like small-molecule activators that improve SERCA’s function for the treatment of heart failure. We have previously demonstrated the use of an intramolecular FRET biosensor, based on human SERCA2a, by screening a small validation library using novel microplate readers that can detect the fluorescence lifetime or emission spectrum with high speed, precision, and resolution. Here we report results from a 50,000-compound screen using the same biosensor, with hit compounds functionally evaluated using Ca 2+ -ATPase and Ca 2+ -transport assays. We focused on 18 hit compounds, from which we identified eight structurally unique compounds and four compound classes as SERCA modulators, approximately half of which are activators and half are inhibitors. While both activators and inhibitors have therapeutic potential, the activators establish the basis for future testing in heart disease models and lead development, toward pharmaceutical therapy for heart failure.
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