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Zechini L, Camilleri-Brennan J, Walsh J, Beaven R, Moran O, Hartley PS, Diaz M, Denholm B. Piezo buffers mechanical stress via modulation of intracellular Ca 2+ handling in the Drosophila heart. Front Physiol 2022; 13:1003999. [PMID: 36187790 PMCID: PMC9515499 DOI: 10.3389/fphys.2022.1003999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
Throughout its lifetime the heart is buffeted continuously by dynamic mechanical forces resulting from contraction of the heart muscle itself and fluctuations in haemodynamic load and pressure. These forces are in flux on a beat-by-beat basis, resulting from changes in posture, physical activity or emotional state, and over longer timescales due to altered physiology (e.g. pregnancy) or as a consequence of ageing or disease (e.g. hypertension). It has been known for over a century of the heart's ability to sense differences in haemodynamic load and adjust contractile force accordingly (Frank, Z. biology, 1895, 32, 370-447; Anrep, J. Physiol., 1912, 45 (5), 307-317; Patterson and Starling, J. Physiol., 1914, 48 (5), 357-79; Starling, The law of the heart (Linacre Lecture, given at Cambridge, 1915), 1918). These adaptive behaviours are important for cardiovascular homeostasis, but the mechanism(s) underpinning them are incompletely understood. Here we present evidence that the mechanically-activated ion channel, Piezo, is an important component of the Drosophila heart's ability to adapt to mechanical force. We find Piezo is a sarcoplasmic reticulum (SR)-resident channel and is part of a mechanism that regulates Ca2+ handling in cardiomyocytes in response to mechanical stress. Our data support a simple model in which Drosophila Piezo transduces mechanical force such as stretch into a Ca2+ signal, originating from the SR, that modulates cardiomyocyte contraction. We show that Piezo mutant hearts fail to buffer mechanical stress, have altered Ca2+ handling, become prone to arrhythmias and undergo pathological remodelling.
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Affiliation(s)
- Luigi Zechini
- Deanery of Biomedical Sciences, Edinburgh Medical School, Edinburgh University, Edinburgh, United Kingtom
- Centre for Inflammation Research, Deanery of Clinical Sciences, Edinburgh Medical School, Edinburgh, United Kingtom
| | - Julian Camilleri-Brennan
- Deanery of Biomedical Sciences, Edinburgh Medical School, Edinburgh University, Edinburgh, United Kingtom
| | - Jonathan Walsh
- Deanery of Biomedical Sciences, Edinburgh Medical School, Edinburgh University, Edinburgh, United Kingtom
| | - Robin Beaven
- Deanery of Biomedical Sciences, Edinburgh Medical School, Edinburgh University, Edinburgh, United Kingtom
| | - Oscar Moran
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche- CNR, Genoa, Italy
| | - Paul S. Hartley
- Department of Life and Environmental Science, Faculty of Science and Technology, Bournemouth University, Poole, United Kingtom
| | - Mary Diaz
- Deanery of Biomedical Sciences, Edinburgh Medical School, Edinburgh University, Edinburgh, United Kingtom
| | - Barry Denholm
- Deanery of Biomedical Sciences, Edinburgh Medical School, Edinburgh University, Edinburgh, United Kingtom
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2
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Schiemann R, Buhr A, Cordes E, Walter S, Heinisch JJ, Ferrero P, Milting H, Paululat A, Meyer H. Neprilysins regulate muscle contraction and heart function via cleavage of SERCA-inhibitory micropeptides. Nat Commun 2022; 13:4420. [PMID: 35906206 PMCID: PMC9338278 DOI: 10.1038/s41467-022-31974-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 07/06/2022] [Indexed: 12/26/2022] Open
Abstract
Muscle contraction depends on strictly controlled Ca2+ transients within myocytes. A major player maintaining these transients is the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase, SERCA. Activity of SERCA is regulated by binding of micropeptides and impaired expression or function of these peptides results in cardiomyopathy. To date, it is not known how homeostasis or turnover of the micropeptides is regulated. Herein, we find that the Drosophila endopeptidase Neprilysin 4 hydrolyzes SERCA-inhibitory Sarcolamban peptides in membranes of the sarcoplasmic reticulum, thereby ensuring proper regulation of SERCA. Cleavage is necessary and sufficient to maintain homeostasis and function of the micropeptides. Analyses on human Neprilysin, sarcolipin, and ventricular cardiomyocytes indicates that the regulatory mechanism is evolutionarily conserved. By identifying a neprilysin as essential regulator of SERCA activity and Ca2+ homeostasis in cardiomyocytes, these data contribute to a more comprehensive understanding of the complex mechanisms that control muscle contraction and heart function in health and disease.
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Affiliation(s)
- Ronja Schiemann
- Department of Zoology & Developmental Biology, Osnabrück University, 49076, Osnabrück, Germany
| | - Annika Buhr
- Department of Zoology & Developmental Biology, Osnabrück University, 49076, Osnabrück, Germany
| | - Eva Cordes
- Department of Zoology & Developmental Biology, Osnabrück University, 49076, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück - CellNanOs, 49076, Osnabrück, Germany
| | - Jürgen J Heinisch
- Center of Cellular Nanoanalytics Osnabrück - CellNanOs, 49076, Osnabrück, Germany.,Department of Genetics, Osnabrück University, 49076, Osnabrück, Germany
| | - Paola Ferrero
- Center for Cardiovascular Research - CONICET/National University of La Plata, 1900, La Plata, Argentina
| | - Hendrik Milting
- Heart & Diabetes Center NRW, University of Bochum, Erich & Hanna Klessmann-Institute for Cardiovascular Research and Development, 32545, Bad Oeynhausen, Germany
| | - Achim Paululat
- Department of Zoology & Developmental Biology, Osnabrück University, 49076, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück - CellNanOs, 49076, Osnabrück, Germany
| | - Heiko Meyer
- Department of Zoology & Developmental Biology, Osnabrück University, 49076, Osnabrück, Germany. .,Center of Cellular Nanoanalytics Osnabrück - CellNanOs, 49076, Osnabrück, Germany.
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3
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Santalla M, García A, Mattiazzi A, Valverde CA, Schiemann R, Paululat A, Hernández G, Meyer H, Ferrero P. Interplay between SERCA, 4E-BP, and eIF4E in the Drosophila heart. PLoS One 2022; 17:e0267156. [PMID: 35588119 PMCID: PMC9119464 DOI: 10.1371/journal.pone.0267156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 04/03/2022] [Indexed: 11/19/2022] Open
Abstract
Appropriate cardiac performance depends on a tightly controlled handling of Ca2+ in a broad range of species, from invertebrates to mammals. The role of the Ca2+ ATPase, SERCA, in Ca2+ handling is pivotal, and its activity is regulated, inter alia, by interacting with distinct proteins. Herein, we give evidence that 4E binding protein (4E-BP) is a novel regulator of SERCA activity in Drosophila melanogaster during cardiac function. Flies over-expressing 4E-BP showed improved cardiac performance in young individuals associated with incremented SERCA activity. Moreover, we demonstrate that SERCA interacts with translation initiation factors eIF4E-1, eIF4E-2 and eIF4E-4 in a yeast two-hybrid assay. The specific identification of eIF4E-4 in cardiac tissue leads us to propose that the interaction of elF4E-4 with SERCA may be the basis of the cardiac effects observed in 4E-BP over-expressing flies associated with incremented SERCA activity.
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Affiliation(s)
- Manuela Santalla
- Departamento de Ciencias Básicas y Experimentales, UNNOBA, Pergamino, Buenos Aires, Argentina
- Centro de Investigaciones Cardiovasculares ‘Dr. Horacio E. Cingolani’, CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Alejandra García
- Translation and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), Mexico City, Mexico
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares ‘Dr. Horacio E. Cingolani’, CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Carlos A. Valverde
- Centro de Investigaciones Cardiovasculares ‘Dr. Horacio E. Cingolani’, CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Ronja Schiemann
- Department of Zoology & Developmental Biology, Osnabrück University, Osnabrück, Germany
| | - Achim Paululat
- Department of Zoology & Developmental Biology, Osnabrück University, Osnabrück, Germany
| | - Greco Hernández
- Translation and Cancer Laboratory, Unit of Biomedical Research on Cancer, National Institute of Cancer (Instituto Nacional de Cancerología, INCan), Mexico City, Mexico
| | - Heiko Meyer
- Department of Zoology & Developmental Biology, Osnabrück University, Osnabrück, Germany
- * E-mail: (PF); (HM)
| | - Paola Ferrero
- Departamento de Ciencias Básicas y Experimentales, UNNOBA, Pergamino, Buenos Aires, Argentina
- Centro de Investigaciones Cardiovasculares ‘Dr. Horacio E. Cingolani’, CONICET-UNLP, La Plata, Buenos Aires, Argentina
- * E-mail: (PF); (HM)
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4
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Rodríguez M, Pagola L, Norry FM, Ferrero P. Cardiac performance in heat-stressed flies of heat-susceptible and heat-resistant Drosophila melanogaster. JOURNAL OF INSECT PHYSIOLOGY 2021; 133:104268. [PMID: 34171365 DOI: 10.1016/j.jinsphys.2021.104268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/24/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
Thermotolerance is a complex trait that can greatly differ between heat-susceptible (HS) and heat-adapted populations of small insects including Drosophila, with short-term effects after a sub-lethal level of heat stress on many physiological functions. Cardiac performance could accordingly be more robust in heat-resistant (HR) than in HS individuals under heat stress. Here, we tested heart performance under heat-stress effects in two recombinant inbred lines (RIL) of Drosophila melanogaster that dramatically differ in heat knockdown resistance. Heart rate did not strongly differ between heat-susceptible and heat-tolerant flies after a sub-lethal heat stress. Instead, heat-susceptible flies showed a much higher arrhythmia incidence, a longer duration of each heartbeat, and a larger amount of bradycardia than heat-tolerant flies. The highly conserved cardiac proteins SERCA, RyR and NCX that participate in the excitation/contraction coupling, did not differ in activity level between HR and HS flies. Available information for both RIL suggests that heart performance under heat stress may be linked, at least partially, to candidate genes of previously identified quantitative trait loci (QTL) for thermotolerance. This study indicates that HR flies can be genetically more robust in their heart performance than HS flies under even sub-lethal levels of heat stress.
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Affiliation(s)
- Maia Rodríguez
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Pergamino 2700, Buenos Aires, Argentina
| | - Lucía Pagola
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Buenos Aires, Argentina
| | - Fabian M Norry
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, C-1428-EHA Buenos Aires, Argentina; Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA) - CONICET, Universidad de Buenos Aires, C-1428-EHA Buenos Aires, Argentina.
| | - Paola Ferrero
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Pergamino 2700, Buenos Aires, Argentina; Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Buenos Aires, Argentina.
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5
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Santalla M, Pagola L, Gómez I, Balcazar D, Valverde CA, Ferrero P. Smoking flies: testing the effect of tobacco cigarettes on heart function of Drosophila melanogaster. Biol Open 2021; 10:bio.055004. [PMID: 33431431 PMCID: PMC7903996 DOI: 10.1242/bio.055004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Studies about the relationship between substances consumed by humans and their impact on health, in animal models, have been a challenge due to differences between species in the animal kingdom. However, the homology of certain genes has allowed extrapolation of certain knowledge obtained in animals. Drosophila melanogaster, studied for decades, has been widely used as model for human diseases as well as to study responses associated with the consumption of several substances. In the present work we explore the impact of tobacco consumption on a model of 'smoking flies'. Throughout these experiments, we aim to provide information about the effects of tobacco consumption on cardiac physiology. We assessed intracellular calcium handling, a phenomenon underlying cardiac contraction and relaxation. Flies chronically exposed to tobacco smoke exhibited an increased heart rate and alterations in the dynamics of the transient increase of intracellular calcium in myocardial cells. These effects were also evident under acute exposure to nicotine of the heart, in a semi-intact preparation. Moreover, the alpha 1 and 7 subunits of the nicotinic receptors are involved in the heart response to tobacco and nicotine under chronic (in the intact fly) as well as acute exposure (in the semi-intact preparation). The present data elucidate the implication of the intracellular cardiac pathways affected by nicotine on the heart tissue. Based on the probed genetic and physiological similarity between the fly and human heart, cardiac effects exerted by tobacco smoke in Drosophila advances our understanding of the impact of it in the human heart. Additionally, it may also provide information on how nicotine-like substances, e.g. neonicotinoids used as insecticides, affect cardiac function.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Manuela Santalla
- Departamento de Ciencias Básicas y Experimentales, UNNOBA, Monteagudo 2772, Pergamino B2700, Argentina.,Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', CONICET, Facultad de Ciencias Médicas, Av 60 & 120. UNLP, La Plata B1900, Argentina
| | - Lucía Pagola
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', CONICET, Facultad de Ciencias Médicas, Av 60 & 120. UNLP, La Plata B1900, Argentina
| | - Ivana Gómez
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', CONICET, Facultad de Ciencias Médicas, Av 60 & 120. UNLP, La Plata B1900, Argentina
| | - Darío Balcazar
- Centro de Estudios Parasitológicos y de Vectores, UNLP-CONICET, Bv 120s/n, La Plata B1900, Argentina
| | - Carlos A Valverde
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', CONICET, Facultad de Ciencias Médicas, Av 60 & 120. UNLP, La Plata B1900, Argentina
| | - Paola Ferrero
- Departamento de Ciencias Básicas y Experimentales, UNNOBA, Monteagudo 2772, Pergamino B2700, Argentina .,Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', CONICET, Facultad de Ciencias Médicas, Av 60 & 120. UNLP, La Plata B1900, Argentina
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6
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Petersen CE, Wolf MJ, Smyth JT. Suppression of store-operated calcium entry causes dilated cardiomyopathy of the Drosophila heart. Biol Open 2020; 9:bio049999. [PMID: 32086252 PMCID: PMC7075072 DOI: 10.1242/bio.049999] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 02/07/2020] [Indexed: 11/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is an essential Ca2+ signaling mechanism present in most animal cells. SOCE refers to Ca2+ influx that is activated by depletion of sarco/endoplasmic reticulum (S/ER) Ca2+ stores. The main components of SOCE are STIM and Orai. STIM proteins function as S/ER Ca2+ sensors, and upon S/ER Ca2+ depletion STIM rearranges to S/ER-plasma membrane junctions and activates Orai Ca2+ influx channels. Studies have implicated SOCE in cardiac hypertrophy pathogenesis, but SOCE's role in normal heart physiology remains poorly understood. We therefore analyzed heart-specific SOCE function in Drosophila, a powerful animal model of cardiac physiology. We show that heart-specific suppression of Stim and Orai in larvae and adults resulted in reduced contractility consistent with dilated cardiomyopathy. Myofibers were also highly disorganized in Stim and Orai RNAi hearts, reflecting possible decompensation or upregulated stress signaling. Furthermore, we show that reduced heart function due to SOCE suppression adversely affected animal viability, as heart specific Stim and Orai RNAi animals exhibited significant delays in post-embryonic development and adults died earlier than controls. Collectively, our results demonstrate that SOCE is essential for physiological heart function, and establish Drosophila as an important model for understanding the role of SOCE in cardiac pathophysiology.
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Affiliation(s)
- Courtney E Petersen
- Graduate Program in Molecular and Cellular Biology, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Matthew J Wolf
- Division of Cardiovascular Medicine, Department of Medicine, The University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Jeremy T Smyth
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
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7
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Mackrill JJ, Shiels HA. Evolution of Excitation-Contraction Coupling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:281-320. [DOI: 10.1007/978-3-030-12457-1_12] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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8
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Gómez IM, Rodríguez MA, Santalla M, Kassis G, Colman Lerner JE, Aranda JO, Sedán D, Andrinolo D, Valverde CA, Ferrero P. Inhalation of marijuana affects Drosophila heart function. Biol Open 2019; 8:bio.044081. [PMID: 31324618 PMCID: PMC6737967 DOI: 10.1242/bio.044081] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We investigated the effect of inhalation of vaporized marijuana on cardiac function in Drosophila melanogaster, a suitable genetic model for studying human diseases. Adult flies were exposed to marijuana for variable time periods and the effects on cardiac function were studied. Short treatment protocol incremented heart-rate variability. Contractility was augmented only under prolonged exposure to cannabis and it was associated with incremented calcium transient within cardiomyocytes. Neither the activity of the major proteins responsible for calcium handling nor the calcium load of the sarcoplasmic reticulum were affected by the cannabis treatment. The observed changes manifested in the cardiomyocytes even in the absence of the canonical cannabinoid receptors described in mammals. Our results are the first evidence of the in vivo impact of phytocannabinoids in D. melanogaster. By providing a simple and affordable platform prior to mammalian models, this characterization of cardiac function under marijuana exposure opens new paths for conducting genetic screenings using vaporized compounds.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Ivana M Gómez
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Argentina
| | - Maia A Rodríguez
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Argentina
| | - Manuela Santalla
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Argentina.,Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Pergamino 2700, Argentina
| | | | - Jorge E Colman Lerner
- Centro de Investigación y Desarrollo en Ciencias Aplicadas Facultad de Ciencias Exactas, CCT La Plata-UNLP-CICPBA, La Plata 1900, Argentina
| | - J Oswaldo Aranda
- Programa Ambiental de Extensión Universitaria. Facultad de Ciencias Exactas-UNLP, La Plata 1900, Argentina
| | - Daniela Sedán
- Centro de Investigaciones del medio Ambiente Facultad de Ciencias Exactas, CCT La Plata-UNLP, La Plata 1900, Argentina
| | - Dario Andrinolo
- Centro de Investigaciones del medio Ambiente Facultad de Ciencias Exactas, CCT La Plata-UNLP, La Plata 1900, Argentina
| | - Carlos A Valverde
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Argentina
| | - Paola Ferrero
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Argentina .,Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Pergamino 2700, Argentina
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9
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Sources of Ca 2+ for contraction of the heart tube of Tenebrio molitor (Coleoptera: Tenebrionidae). J Comp Physiol B 2018; 188:929-937. [PMID: 30218147 DOI: 10.1007/s00360-018-1183-0] [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: 07/13/2018] [Accepted: 09/06/2018] [Indexed: 10/28/2022]
Abstract
Insect and vertebrate hearts share the ability to generate spontaneously their rhythmic electrical activity, which triggers the fluid-propelling mechanical activity. Although insects have been used as models in studies on the impact of genetic alterations on cardiac function, there is surprisingly little information on the generation of the inotropic activity in their hearts. The main goal of this study was to investigate the sources of Ca2+ for contraction in Tenebrio molitor hearts perfused in situ, in which inotropic activity was assessed by the systolic variation of the cardiac luminal diameter. Increasing the pacing rate from 1.0 to 2.5 Hz depressed contraction amplitude and accelerated relaxation. To avoid inotropic interference of variations in spontaneous rate, which have been shown to occur in insect heart during maneuvers that affect Ca2+ cycling, experiments were performed under electrical pacing at near-physiological rates. Raising the extracellular Ca2+ concentration from 0.5 to 8 mM increased contraction amplitude in a manner sensitive to L-type Ca2+ channel blockade by D600. Inotropic depression was observed after treatment with caffeine or thapsigargin, which impair Ca2+ accumulation by the sarcoplasmic reticulum (SR). D600, but not inhibition of the sarcolemmal Na+/Ca2+ exchanger by KB-R7943, further depressed inotropic activity in thapsigargin-treated hearts. From these results, it is possible to conclude that in T. molitor heart, as in vertebrates: (a) inotropic and lusitropic activities are modulated by the heart rate; and (b) Ca2+ availability for contraction depends on both Ca2+ influx via L-type channels and Ca2+ release from the SR.
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10
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Balcazar D, Regge V, Santalla M, Meyer H, Paululat A, Mattiazzi A, Ferrero P. SERCA is critical to control the Bowditch effect in the heart. Sci Rep 2018; 8:12447. [PMID: 30127403 PMCID: PMC6102201 DOI: 10.1038/s41598-018-30638-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/16/2018] [Indexed: 11/08/2022] Open
Abstract
The Bowditch effect or staircase phenomenon is the increment or reduction of contractile force when heart rate increases, defined as either a positive or negative staircase. The healthy and failing human heart both show positive or negative staircase, respectively, but the causes of these distinct cardiac responses are unclear. Different experimental approaches indicate that while the level of Ca2+ in the sarcoplasmic reticulum is critical, the molecular mechanisms are unclear. Here, we demonstrate that Drosophila melanogaster shows a negative staircase which is associated to a slight but significant frequency-dependent acceleration of relaxation (FDAR) at the highest stimulation frequencies tested. We further showed that the type of staircase is oppositely modified by two distinct SERCA mutations. The dominant conditional mutation SERCAA617T induced positive staircase and arrhythmia, while SERCAE442K accentuated the negative staircase of wild type. At the stimulation frequencies tested, no significant FDAR could be appreciated in mutant flies. The present results provide evidence that two individual mutations directly modify the type of staircase occurring within the heart and suggest an important role of SERCA in regulating the Bowditch effect.
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Affiliation(s)
- Darío Balcazar
- Centro de Investigaciones Cardiovasculares - CONICET/Universidad Nacional de la Plata, La Plata, Argentina
| | - Victoria Regge
- Centro de Investigaciones Cardiovasculares - CONICET/Universidad Nacional de la Plata and Departamento de Ciencias Básicas y Experimentales -UNNOBA, La Plata, Argentina
| | - Manuela Santalla
- Centro de Investigaciones Cardiovasculares - CONICET/Universidad Nacional de la Plata and Departamento de Ciencias Básicas y Experimentales -UNNOBA, La Plata, Argentina
| | - Heiko Meyer
- University of Osnabrück, Biology, Department of Zoology and Developmental Biology, Barbarastraße 11, 49076, Osnabrück, Germany
| | - Achim Paululat
- University of Osnabrück, Biology, Department of Zoology and Developmental Biology, Barbarastraße 11, 49076, Osnabrück, Germany
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares - CONICET/Universidad Nacional de la Plata, La Plata, Argentina
| | - Paola Ferrero
- Centro de Investigaciones Cardiovasculares - CONICET/Universidad Nacional de la Plata and Departamento de Ciencias Básicas y Experimentales -UNNOBA, La Plata, Argentina.
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11
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Abstract
Heart failure places an enormous burden on health and economic systems worldwide. It is a complex disease that is profoundly influenced by both genetic and environmental factors. Neither the molecular mechanisms underlying heart failure nor effective prevention strategies are fully understood. Fortunately, relevant aspects of human heart failure can be experimentally studied in tractable model animals, including the fruit fly, Drosophila, allowing the in vivo application of powerful and sophisticated molecular genetic and physiological approaches. Heart failure in Drosophila, as in humans, can be classified into dilated cardiomyopathies and hypertrophic cardiomyopathies. Critically, many genes and cellular pathways directing heart development and function are evolutionarily conserved from Drosophila to humans. Studies of molecular mechanisms linking aging with heart failure have revealed that genes involved in aging-associated energy homeostasis and oxidative stress resistance influence cardiac dysfunction through perturbation of IGF and TOR pathways. Importantly, ion channel proteins, cytoskeletal proteins, and integrins implicated in aging of the mammalian heart have been shown to play significant roles in heart failure. A number of genes previously described having roles in development of the Drosophila heart, such as genes involved in Wnt signaling pathways, have recently been shown to play important roles in the adult fly heart. Moreover, the fly model presents opportunities for innovative studies that cannot currently be pursued in the mammalian heart because of technical limitations. In this review, we discuss progress in our understanding of genes, proteins, and molecular mechanisms that affect the Drosophila adult heart and heart failure.
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Affiliation(s)
- Shasha Zhu
- The Center for Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China
| | - Zhe Han
- Center for Cancer and Immunology Research, Children's National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010, USA
| | - Yan Luo
- The Center for Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China
| | - Yulin Chen
- The Center for Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China
| | - Qun Zeng
- The Center for Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China
| | - Xiushan Wu
- The Center for Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China.
| | - Wuzhou Yuan
- The Center for Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China.
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Mönck H, Toppe D, Michael E, Sigrist S, Richter V, Hilpert D, Raccuglia D, Efetova M, Schwärzel M. A new method to characterize function of the Drosophila heart by means of optical flow. J Exp Biol 2017; 220:4644-4653. [DOI: 10.1242/jeb.164343] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/09/2017] [Indexed: 01/05/2023]
Abstract
ABSTRACT
The minuteness of Drosophila poses a challenge to quantify performance of its tubular heart and computer-aided analysis of its beating heart has evolved as a resilient compromise between instrumental costs and data robustness. Here, we introduce an optical flow algorithm (OFA) that continuously registers coherent movement within videos of the beating Drosophila heart and uses this information to subscribe the time course of observation with characteristic phases of cardiac contraction or relaxation. We report that the OFA combines high discriminatory power with robustness to characterize the performance of the Drosophila tubular heart using indicators from human cardiology. We provide proof of this concept using the test bed of established cardiac conditions that include the effects of ageing, knockdown of the slow repolarizing potassium channel subunit KCNQ and ras-mediated hypertrophy of the heart tube. Together, this establishes the analysis of coherent movement as a suitable indicator of qualitative changes of the heart's beating characteristics, which improves the usefulness of Drosophila as a model of cardiac diseases.
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Affiliation(s)
- Hauke Mönck
- Freie Universität Berlin, Department of Biology/Neurobiology, Königin-Luise Strasse 28-30, D-14195 Berlin, Germany
| | - David Toppe
- Freie Universität Berlin, Department of Biology/Neurobiology, Königin-Luise Strasse 28-30, D-14195 Berlin, Germany
| | - Eva Michael
- Freie Universität Berlin, Department of Biology/Neurogenetics, Takustrasse 6, D-14195 Berlin, Germany
| | - Stephan Sigrist
- Freie Universität Berlin, Department of Biology/Neurogenetics, Takustrasse 6, D-14195 Berlin, Germany
| | - Vincent Richter
- Freie Universität Berlin, Department of Biology/Neurobiology, Königin-Luise Strasse 28-30, D-14195 Berlin, Germany
| | - Diana Hilpert
- Freie Universität Berlin, Department of Biology/Neurobiology, Königin-Luise Strasse 28-30, D-14195 Berlin, Germany
| | - Davide Raccuglia
- Institute of Neurophysiology, Charité - Universitätsmedizin, 10117 Berlin, Germany
| | - Marina Efetova
- Freie Universität Berlin, Department of Biology/Neurobiology, Königin-Luise Strasse 28-30, D-14195 Berlin, Germany
| | - Martin Schwärzel
- Freie Universität Berlin, Department of Biology/Neurobiology, Königin-Luise Strasse 28-30, D-14195 Berlin, Germany
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Li Y, Asfour H, Bursac N. Age-dependent functional crosstalk between cardiac fibroblasts and cardiomyocytes in a 3D engineered cardiac tissue. Acta Biomater 2017; 55:120-130. [PMID: 28455218 DOI: 10.1016/j.actbio.2017.04.027] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 04/18/2017] [Accepted: 04/24/2017] [Indexed: 10/19/2022]
Abstract
Complex heterocellular interactions between cardiomyocytes and fibroblasts in the heart involve their bidirectional signaling via cell-cell contacts, paracrine factors, and extracellular matrix (ECM). These interactions vary with heart development and pathology leading to changes in cardiac structure and function. Whether cardiac fibroblasts of different ages interact differentially with cardiomyocytes to distinctly impact their function remains unknown. Here, we explored the direct structural and functional effects of fetal and adult cardiac fibroblasts on cardiomyocytes using a tissue-engineered 3D co-culture system. We show that the age of cardiac fibroblasts is a strong determinant of the structure, function, and molecular properties of co-cultured tissues. In particular, in vitro expanded adult, but not fetal, cardiac fibroblasts significantly deteriorated electrical and mechanical function of the co-cultured cardiomyocytes, as evidenced by slower action potential conduction, prolonged action potential duration, weaker contractions, higher tissue stiffness, and reduced calcium transient amplitude. This functional deficit was associated with structural and molecular signatures of pathological remodeling including fibroblast proliferation, interstitial collagen deposition, and upregulation of pro-fibrotic markers. Our studies imply critical roles of the age of supporting cells in engineering functional cardiac tissues and provide a new physiologically relevant in vitro platform to investigate influence of heterocellular interactions on cardiomyocyte function, development, and disease. STATEMENT OF SIGNIFICANCE Previous studies have shown that cardiomyocytes and fibroblasts in the heart interact through direct contacts, paracrine factors, and matrix-mediated crosstalk. However, whether cardiac fibroblasts of different ages distinctly impact cardiomyocyte function remains elusive. We employed a tissue-engineered hydrogel-based co-culture system to study interactions of cardiomyocytes with fetal or adult cardiac fibroblasts. We show that the age of cardiac fibroblasts is a strong determinant of the structure, function, and molecular properties of engineered cardiac tissues and that key features of fibrotic myocardium are replicated by supplementing cardiomyocytes with expanded adult but not fetal fibroblasts. These findings relate to implantation of stem cell-derived cardiomyocytes in adult myocardium and warrant further studies of how age and source of non-myocytes impact cardiac function and maturation.
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14
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Ugur B, Chen K, Bellen HJ. Drosophila tools and assays for the study of human diseases. Dis Model Mech 2016; 9:235-44. [PMID: 26935102 PMCID: PMC4833332 DOI: 10.1242/dmm.023762] [Citation(s) in RCA: 296] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Many of the internal organ systems of Drosophila melanogaster are functionally analogous to those in vertebrates, including humans. Although humans and flies differ greatly in terms of their gross morphological and cellular features, many of the molecular mechanisms that govern development and drive cellular and physiological processes are conserved between both organisms. The morphological differences are deceiving and have led researchers to undervalue the study of invertebrate organs in unraveling pathogenic mechanisms of diseases. In this review and accompanying poster, we highlight the physiological and molecular parallels between fly and human organs that validate the use of Drosophila to study the molecular pathogenesis underlying human diseases. We discuss assays that have been developed in flies to study the function of specific genes in the central nervous system, heart, liver and kidney, and provide examples of the use of these assays to address questions related to human diseases. These assays provide us with simple yet powerful tools to study the pathogenic mechanisms associated with human disease-causing genes. Editors' choice - Drosophila Collection: In this review and accompanying poster, we highlight the physiological and molecular parallels between fly and human organs that validate the use of Drosophila to study the molecular pathogenesis underlying human diseases.
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Affiliation(s)
- Berrak Ugur
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
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15
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Taghli-Lamallem O, Plantié E, Jagla K. Drosophila in the Heart of Understanding Cardiac Diseases: Modeling Channelopathies and Cardiomyopathies in the Fruitfly. J Cardiovasc Dev Dis 2016; 3:jcdd3010007. [PMID: 29367558 PMCID: PMC5715700 DOI: 10.3390/jcdd3010007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 01/23/2016] [Accepted: 02/06/2016] [Indexed: 12/16/2022] Open
Abstract
Cardiovascular diseases and, among them, channelopathies and cardiomyopathies are a major cause of death worldwide. The molecular and genetic defects underlying these cardiac disorders are complex, leading to a large range of structural and functional heart phenotypes. Identification of molecular and functional mechanisms disrupted by mutations causing channelopathies and cardiomyopathies is essential to understanding the link between an altered gene and clinical phenotype. The development of animal models has been proven to be efficient for functional studies in channelopathies and cardiomyopathies. In particular, the Drosophila model has been largely applied for deciphering the molecular and cellular pathways affected in these inherited cardiac disorders and for identifying their genetic modifiers. Here we review the utility and the main contributions of the fruitfly models for the better understanding of channelopathies and cardiomyopathies. We also discuss the investigated pathological mechanisms and the discoveries of evolutionarily conserved pathways which reinforce the value of Drosophila in modeling human cardiac diseases.
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Affiliation(s)
- Ouarda Taghli-Lamallem
- GReD (Genetics, Reproduction and Development laboratory), INSERM U1103, CNRS UMR6293, University of Clermont-Ferrand, 28 place Henri-Dunant, 63000 Clermont-Ferrand, France.
| | - Emilie Plantié
- GReD (Genetics, Reproduction and Development laboratory), INSERM U1103, CNRS UMR6293, University of Clermont-Ferrand, 28 place Henri-Dunant, 63000 Clermont-Ferrand, France.
| | - Krzysztof Jagla
- GReD (Genetics, Reproduction and Development laboratory), INSERM U1103, CNRS UMR6293, University of Clermont-Ferrand, 28 place Henri-Dunant, 63000 Clermont-Ferrand, France.
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16
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Enhanced assessment of contractile dynamics in Drosophila hearts. Biotechniques 2015; 58:77-80. [PMID: 25652030 DOI: 10.2144/000114255] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/21/2014] [Indexed: 11/23/2022] Open
Abstract
The Drosophila heart has gained considerable traction as a model of cardiac development and physiology. Previously we described a semiautomatic optical heartbeat analysis (SOHA) method for quantifying functional parameters from the fly heart that facilitated its use as an organ system and disease model. Here we present an extensively rewritten version of the original SOHA program that takes advantage of additional information contained in high-speed videos of beating hearts. Program updates allow more precise quantification of cardiac contractions, increase the signal-to-noise ratio, and reduce the overall cost and time required to analyze recordings. This new SOHA version permits relatively rapid and highly accurate determination of subphases of contraction and relaxation. Importantly, the improved functionality enables the calculation of novel physiological data, suggesting that the fly model system may also be practical for screening drugs and alleles that modulate cardiac repolarization and force production.
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17
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Santalla M, Valverde CA, Harnichar E, Lacunza E, Aguilar-Fuentes J, Mattiazzi A, Ferrero P. Aging and CaMKII alter intracellular Ca2+ transients and heart rhythm in Drosophila melanogaster. PLoS One 2014; 9:e101871. [PMID: 25003749 PMCID: PMC4087024 DOI: 10.1371/journal.pone.0101871] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 06/12/2014] [Indexed: 11/18/2022] Open
Abstract
Aging is associated to disrupted contractility and rhythmicity, among other cardiovascular alterations. Drosophila melanogaster shows a pattern of aging similar to human beings and recapitulates the arrhythmogenic conditions found in the human heart. Moreover, the kinase CaMKII has been characterized as an important regulator of heart function and an arrhythmogenic molecule that participate in Ca2+ handling. Using a genetically engineered expressed Ca2+ indicator, we report changes in cardiac Ca2+ handling at two different ages. Aging prolonged relaxation, reduced spontaneous heart rate (HR) and increased the occurrence of arrhythmias, ectopic beats and asystoles. Alignment between Drosophila melanogaster and human CaMKII showed a high degree of conservation and indicates that relevant phosphorylation sites in humans are also present in the fruit fly. Inhibition of CaMKII by KN-93 (CaMKII-specific inhibitor), reduced HR without significant changes in other parameters. By contrast, overexpression of CaMKII increased HR and reduced arrhythmias. Moreover, it increased fluorescence amplitude, maximal rate of rise of fluorescence and reduced time to peak fluorescence. These results suggest that CaMKII in Drosophila melanogaster acts directly on heart function and that increasing CaMKII expression levels could be beneficial to improve contractility.
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Affiliation(s)
- Manuela Santalla
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de Buenos Aires, Pergamino, Buenos Aires, Argentina
| | - Carlos A. Valverde
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Ezequiel Harnichar
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Ezequiel Lacunza
- Centro de Investigaciones Inmunológicas Básicas y Aplicadas, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata La Plata, Buenos Aires, Argentina
| | - Javier Aguilar-Fuentes
- Universidad Autónoma de Chiapas, Centro Mesoamericano de Estudios en Salud Pública y Desastres, Nodo Tapachula, Laboratorio de Epigenética del Neurodesarrollo y Neurobiología Molecular, Tapachula, Chiapas, México
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Paola Ferrero
- Centro de Investigaciones Cardiovasculares, CONICET-La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de Buenos Aires, Pergamino, Buenos Aires, Argentina
- * E-mail:
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18
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Kooij V, Venkatraman V, Tra J, Kirk JA, Rowell J, Blice-Baum A, Cammarato A, Van Eyk JE. Sizing up models of heart failure: Proteomics from flies to humans. Proteomics Clin Appl 2014; 8:653-64. [PMID: 24723306 PMCID: PMC4282793 DOI: 10.1002/prca.201300123] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/31/2014] [Accepted: 04/03/2014] [Indexed: 12/25/2022]
Abstract
Cardiovascular disease is the leading cause of death in the western world. Heart failure is a heterogeneous and complex syndrome, arising from various etiologies, which result in cellular phenotypes that vary from patient to patient. The ability to utilize genetic manipulation and biochemical experimentation in animal models has made them indispensable in the study of this chronic condition. Similarly, proteomics has been helpful for elucidating complicated cellular and molecular phenotypes and has the potential to identify circulating biomarkers and drug targets for therapeutic intervention. In this review, the use of human samples and animal model systems (pig, dog, rat, mouse, zebrafish, and fruit fly) in cardiac research is discussed. Additionally, the protein sequence homology between these species and the extent of conservation at the level of the phospho-proteome in major kinase signaling cascades involved in heart failure are investigated.
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Affiliation(s)
- Viola Kooij
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
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19
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Viswanathan MC, Kaushik G, Engler AJ, Lehman W, Cammarato A. A Drosophila melanogaster model of diastolic dysfunction and cardiomyopathy based on impaired troponin-T function. Circ Res 2013; 114:e6-17. [PMID: 24221941 DOI: 10.1161/circresaha.114.302028] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RATIONALE Regulation of striated muscle contraction is achieved by Ca2+ -dependent steric modulation of myosin cross-bridge cycling on actin by the thin filament troponin-tropomyosin complex. Alterations in the complex can induce contractile dysregulation and disease. For example, mutations between or near residues 112 to 136 of cardiac troponin-T, the crucial TnT1 (N-terminal domain of troponin-T)-tropomyosin-binding region, cause cardiomyopathy. The Drosophila upheld(101) Glu/Lys amino acid substitution lies C-terminally adjacent to this phylogenetically conserved sequence. OBJECTIVE Using a highly integrative approach, we sought to determine the molecular trigger of upheld(101) myofibrillar degeneration, to evaluate contractile performance in the mutant cardiomyocytes, and to examine the effects of the mutation on the entire Drosophila heart to elucidate regulatory roles for conserved TnT1 regions and provide possible mechanistic insight into cardiac dysfunction. METHODS AND RESULTS Live video imaging of Drosophila cardiac tubes revealed that the troponin-T mutation prolongs systole and restricts diastolic dimensions of the heart, because of increased numbers of actively cycling myosin cross-bridges. Elevated resting myocardial stiffness, consistent with upheld(101) diastolic dysfunction, was confirmed by an atomic force microscopy-based nanoindentation approach. Direct visualization of mutant thin filaments via electron microscopy and 3-dimensional reconstruction resolved destabilized tropomyosin positioning and aberrantly exposed myosin-binding sites under low Ca2+ conditions. CONCLUSIONS As a result of troponin-tropomyosin dysinhibition, upheld(101) hearts exhibited cardiac dysfunction and remodeling comparable to that observed during human restrictive cardiomyopathy. Thus, reversal of charged residues about the conserved tropomyosin-binding region of TnT1 may perturb critical intermolecular associations required for proper steric regulation, which likely elicits myopathy in our Drosophila model.
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Affiliation(s)
- Meera Cozhimuttam Viswanathan
- From the Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (M.C.V., A.C.); Department of Bioengineering, University of California, San Diego, La Jolla, CA (G.K., A.J.E.); and Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA (W.L.)
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20
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Magny EG, Pueyo JI, Pearl FMG, Cespedes MA, Niven JE, Bishop SA, Couso JP. Conserved regulation of cardiac calcium uptake by peptides encoded in small open reading frames. Science 2013; 341:1116-20. [PMID: 23970561 DOI: 10.1126/science.1238802] [Citation(s) in RCA: 257] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Small open reading frames (smORFs) are short DNA sequences that are able to encode small peptides of less than 100 amino acids. Study of these elements has been neglected despite thousands existing in our genomes. We and others previously showed that peptides as short as 11 amino acids are translated and provide essential functions during insect development. Here, we describe two peptides of less than 30 amino acids regulating calcium transport, and hence influencing regular muscle contraction, in the Drosophila heart. These peptides seem conserved for more than 550 million years in a range of species from flies to humans, in which they have been implicated in cardiac pathologies. Such conservation suggests that the mechanisms for heart regulation are ancient and that smORFs may be a fundamental genome component that should be studied systematically.
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Affiliation(s)
- Emile G Magny
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex BN1 9QG, UK
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21
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Circulation Research thematic synopsis: mitochondria. Circ Res 2013; 112:e55-67. [PMID: 23493305 DOI: 10.1161/circresaha.113.301165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Circulation Research
Thematic Synopsis. Circ Res 2012. [DOI: 10.1161/circresaha.112.279091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
During the past 100 years, the fruit fly, Drosophila melanogaster, has provided tremendous insights into genetics and human biology. Drosophila-based research utilizes powerful, genetically tractable approaches to identify new genes and pathways that potentially contribute to human diseases. New resources available in the fly research community have advanced the ability to examine genome-wide effects on cardiac function and facilitate the identification of structural, contractile, and signaling molecules that contribute to cardiomyopathies. This powerful model system continues to provide discoveries of novel genes and signaling pathways that are conserved among species and translatable to human pathophysiology.
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Affiliation(s)
- Matthew J Wolf
- Division of Cardiology, Duke University Medical Center, Durham, NC 27710, USA.
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24
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Houser SR, Margulies KB, Murphy AM, Spinale FG, Francis GS, Prabhu SD, Rockman HA, Kass DA, Molkentin JD, Sussman MA, Koch WJ. Animal models of heart failure: a scientific statement from the American Heart Association. Circ Res 2012; 111:131-50. [PMID: 22595296 DOI: 10.1161/res.0b013e3182582523] [Citation(s) in RCA: 324] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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25
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Abstract
The fruit fly, Drosophila melanogaster, has been used to study genetics, development, and signaling for nearly a century, but only over the past few decades has this tremendous resource been the focus of cardiovascular research. Fly genetics offers sophisticated transgenic systems, molecularly defined genomic deficiencies, genome-wide transgenic RNAi lines, and numerous curated mutants to perform genetic screens. As a genetically tractable model, the fly facilitates gene discovery and can complement mammalian models of disease. The circulatory system in the fly comprises well-defined sets of cardiomyocytes, and methodological advances have permitted accurate characterization of cardiac morphology and function. Thus, fly genetics and genomics offer new approaches for gene discovery of adult cardiac phenotypes to identify evolutionarily conserved molecular signals that drive cardiovascular disease.
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Affiliation(s)
- Matthew J Wolf
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
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26
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Harpaz N, Volk T. A novel method for obtaining semi-thin cross sections of the Drosophila heart and their labeling with multiple antibodies. Methods 2011; 56:63-8. [PMID: 21963658 DOI: 10.1016/j.ymeth.2011.09.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/17/2011] [Accepted: 09/02/2011] [Indexed: 10/17/2022] Open
Abstract
The Drosophila heart has become an exciting model for elucidating the molecular basis for cardiac function in higher organisms. To complement the genetic approaches that have recently identified an array of genes essential for cardiac function, we developed a method to obtain optimal semi-thin cross sections of embryonic, larval, and adult fly hearts in a desired orientation. A procedure for fluorescent labeling of these sections with multiple markers has also been developed, allowing the detection of proteins at high subcellular resolution. Sections obtained by our method reveal changes in cell shape between embryonic heart and aorta cardioblasts and elucidate the morphology of the adult heart. Analysis of the adult heart reveals the precise cardiac tube morphology, differential distribution of the extracellular matrix protein Laminin within the cardiac tube, as well as individual hand-positive, and Held Out Wings (HOW)-positive luminal cells that might represent blood cells. In summary, our method enables visualization of cross sections of the embryonic and adult hearts at high resolution while maintaining the ability to co-label the sections with multiple markers, thereby facilitating the analysis of cardiac tube formation and maintenance at different developmental stages.
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Affiliation(s)
- Nofar Harpaz
- Weizmann Institute of Science, Rehovot 76100, Israel
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27
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Shining light on Drosophila oogenesis: live imaging of egg development. Curr Opin Genet Dev 2011; 21:612-9. [PMID: 21930372 DOI: 10.1016/j.gde.2011.08.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/29/2011] [Accepted: 08/30/2011] [Indexed: 12/31/2022]
Abstract
Drosophila oogenesis is a powerful model for the study of numerous questions in cell and developmental biology. In addition to its longstanding value as a genetically tractable model of organogenesis, recently it has emerged as an excellent system in which to combine genetics and live imaging. Rapidly improving ex vivo culture conditions, new fluorescent biosensors and photo-manipulation tools, and advances in microscopy have allowed direct observation in real time of processes such as stem cell self-renewal, collective cell migration, and polarized mRNA and protein transport. In addition, entirely new phenomena have been discovered, including revolution of the follicle within the basement membrane and oscillating assembly and disassembly of myosin on a polarized actin network, both of which contribute to elongating this tissue. This review focuses on recent advances in live-cell imaging techniques and the biological insights gleaned from live imaging of egg chamber development.
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28
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Bloemink MJ, Melkani GC, Dambacher CM, Bernstein SI, Geeves MA. Two Drosophila myosin transducer mutants with distinct cardiomyopathies have divergent ADP and actin affinities. J Biol Chem 2011; 286:28435-43. [PMID: 21680742 PMCID: PMC3151086 DOI: 10.1074/jbc.m111.258228] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Two Drosophila myosin II point mutations (D45 and Mhc(5)) generate Drosophila cardiac phenotypes that are similar to dilated or restrictive human cardiomyopathies. Our homology models suggest that the mutations (A261T in D45, G200D in Mhc(5)) could stabilize (D45) or destabilize (Mhc(5)) loop 1 of myosin, a region known to influence ADP release. To gain insight into the molecular mechanism that causes the cardiomyopathic phenotypes to develop, we determined whether the kinetic properties of the mutant molecules have been altered. We used myosin subfragment 1 (S1) carrying either of the two mutations (S1(A261T) and S1(G200D)) from the indirect flight muscles of Drosophila. The kinetic data show that the two point mutations have an opposite effect on the enzymatic activity of S1. S1(A261T) is less active (reduced ATPase, higher ADP affinity for S1 and actomyosin subfragment 1 (actin · S1), and reduced ATP-induced dissociation of actin · S1), whereas S1(G200D) shows increased enzymatic activity (enhanced ATPase, reduced ADP affinity for both S1 and actin · S1). The opposite changes in the myosin properties are consistent with the induced cardiac phenotypes for S1(A261T) (dilated) and S1(G200D) (restrictive). Our results provide novel insights into the molecular mechanisms that cause different cardiomyopathy phenotypes for these mutants. In addition, we report that S1(A261T) weakens the affinity of S1 · ADP for actin, whereas S1(G200D) increases it. This may account for the suppression (A261T) or enhancement (G200D) of the skeletal muscle hypercontraction phenotype induced by the troponin I held-up(2) mutation in Drosophila.
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Affiliation(s)
- Marieke J Bloemink
- Department of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, United Kingdom
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