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Gandhi S, Sweeney HL, Hart CC, Han R, Perry CGR. Cardiomyopathy in Duchenne Muscular Dystrophy and the Potential for Mitochondrial Therapeutics to Improve Treatment Response. Cells 2024; 13:1168. [PMID: 39056750 PMCID: PMC11274633 DOI: 10.3390/cells13141168] [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: 01/27/2024] [Revised: 07/05/2024] [Accepted: 07/06/2024] [Indexed: 07/28/2024] Open
Abstract
Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease caused by mutations to the dystrophin gene, resulting in deficiency of dystrophin protein, loss of myofiber integrity in skeletal and cardiac muscle, and eventual cell death and replacement with fibrotic tissue. Pathologic cardiac manifestations occur in nearly every DMD patient, with the development of cardiomyopathy-the leading cause of death-inevitable by adulthood. As early cardiac abnormalities are difficult to detect, timely diagnosis and appropriate treatment modalities remain a challenge. There is no cure for DMD; treatment is aimed at delaying disease progression and alleviating symptoms. A comprehensive understanding of the pathophysiological mechanisms is crucial to the development of targeted treatments. While established hypotheses of underlying mechanisms include sarcolemmal weakening, upregulation of pro-inflammatory cytokines, and perturbed ion homeostasis, mitochondrial dysfunction is thought to be a potential key contributor. Several experimental compounds targeting the skeletal muscle pathology of DMD are in development, but the effects of such agents on cardiac function remain unclear. The synergistic integration of small molecule- and gene-target-based drugs with metabolic-, immune-, or ion balance-enhancing compounds into a combinatorial therapy offers potential for treating dystrophin deficiency-induced cardiomyopathy, making it crucial to understand the underlying mechanisms driving the disorder.
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Affiliation(s)
- Shivam Gandhi
- School of Kinesiology and Health Science, Muscle Health Research Centre, York University, Toronto, ON M3J 1P3, Canada
| | - H. Lee Sweeney
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA; (H.L.S.); (C.C.H.)
- Myology Institute, University of Florida, Gainesville, FL 32610, USA
| | - Cora C. Hart
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA; (H.L.S.); (C.C.H.)
- Myology Institute, University of Florida, Gainesville, FL 32610, USA
| | - Renzhi Han
- Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Christopher G. R. Perry
- School of Kinesiology and Health Science, Muscle Health Research Centre, York University, Toronto, ON M3J 1P3, Canada
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2
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Tubert C, Zampese E, Pancani T, Tkatch T, Surmeier DJ. Feed-forward metabotropic signaling by Cav1 Ca 2+ channels supports pacemaking in pedunculopontine cholinergic neurons. Neurobiol Dis 2023; 188:106328. [PMID: 37852390 PMCID: PMC10792542 DOI: 10.1016/j.nbd.2023.106328] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/14/2023] [Accepted: 10/15/2023] [Indexed: 10/20/2023] Open
Abstract
Like a handful of other neuronal types in the brain, cholinergic neurons (CNs) in the pedunculopontine nucleus (PPN) are lost during Parkinson's disease (PD). Why this is the case is unknown. One neuronal trait implicated in PD selective neuronal vulnerability is the engagement of feed-forward stimulation of mitochondrial oxidative phosphorylation (OXPHOS) to meet high bioenergetic demand, leading to sustained oxidant stress and ultimately degeneration. The extent to which this trait is shared by PPN CNs is unresolved. To address this question, a combination of molecular and physiological approaches were used. These studies revealed that PPN CNs are autonomous pacemakers with modest spike-associated cytosolic Ca2+ transients. These Ca2+ transients were partly attributable to the opening of high-threshold Cav1.2 Ca2+ channels, but not Cav1.3 channels. Cav1.2 channel signaling through endoplasmic reticulum ryanodine receptors stimulated mitochondrial OXPHOS to help maintain cytosolic adenosine triphosphate (ATP) levels necessary for pacemaking. Inhibition of Cav1.2 channels led to the recruitment of ATP-sensitive K+ channels and the slowing of pacemaking. A 'side-effect' of Cav1.2 channel-mediated stimulation of mitochondria was increased oxidant stress. Thus, PPN CNs have a distinctive physiological phenotype that shares some, but not all, of the features of other neurons that are selectively vulnerable in PD.
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Affiliation(s)
- C Tubert
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Universidad de Buenos Aires - CONICET. Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Facultad de Medicina, Departamento de Ciencias Fisiológicas, Grupo de Neurociencia de Sistemas, Buenos Aires, Argentina
| | - E Zampese
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - T Pancani
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Max Planck Florida Institute for Neuroscience, 1 Max Planck Way, Jupiter, FL 33458, USA
| | - T Tkatch
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - D J Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA.
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3
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Tubert C, Zampese E, Pancani T, Tkatch T, Surmeier DJ. Feed-forward metabotropic signaling by Cav1 Ca 2+ channels supports pacemaking in pedunculopontine cholinergic neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.05.552108. [PMID: 37609299 PMCID: PMC10441306 DOI: 10.1101/2023.08.05.552108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Like a handful of other neuronal types in the brain, cholinergic neurons (CNs) in the pedunculopontine nucleus (PPN) are lost in the course of Parkinson's disease (PD). Why this is the case is unknown. One neuronal trait implicated in PD selective neuronal vulnerability is the engagement of feed-forward stimulation of mitochondrial oxidative phosphorylation (OXPHOS) to meet high bioenergetic demand, leading to sustained oxidant stress and ultimately degeneration. The extent to which this trait is shared by PPN CNs is unresolved. To address this question, a combination of molecular and physiological approaches were used. These studies revealed that PPN CNs are autonomous pacemakers with modest spike-associated cytosolic Ca 2+ transients. These Ca 2+ transients were attributable in part to the opening of high-threshold Cav1.2 Ca 2+ channels, but not Cav1.3 channels. Nevertheless, Cav1.2 channel signaling through endoplasmic reticulum ryanodine receptors stimulated mitochondrial OXPHOS to help maintain cytosolic adenosine triphosphate (ATP) levels necessary for pacemaking. Inhibition of Cav1.2 channels led to recruitment of ATP-sensitive K + channels and slowing of pacemaking. Cav1.2 channel-mediated stimulation of mitochondria increased oxidant stress. Thus, PPN CNs have a distinctive physiological phenotype that shares some, but not all, of the features of other neurons that are selectively vulnerable in PD.
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4
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A maladaptive feedback mechanism between the extracellular matrix and cytoskeleton contributes to hypertrophic cardiomyopathy pathophysiology. Commun Biol 2023; 6:4. [PMID: 36596888 PMCID: PMC9810744 DOI: 10.1038/s42003-022-04278-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 11/17/2022] [Indexed: 01/04/2023] Open
Abstract
Hypertrophic cardiomyopathy is an inherited disorder due to mutations in contractile proteins that results in a stiff, hypercontractile myocardium. To understand the role of cardiac stiffness in disease progression, here we create an in vitro model of hypertrophic cardiomyopathy utilizing hydrogel technology. Culturing wild-type cardiac myocytes on hydrogels with a Young's Moduli (stiffness) mimicking hypertrophic cardiomyopathy myocardium is sufficient to induce a hypermetabolic mitochondrial state versus myocytes plated on hydrogels simulating healthy myocardium. Significantly, these data mirror that of myocytes isolated from a murine model of human hypertrophic cardiomyopathy (cTnI-G203S). Conversely, cTnI-G203S myocyte mitochondrial function is completely restored when plated on hydrogels mimicking healthy myocardium. We identify a mechanosensing feedback mechanism between the extracellular matrix and cytoskeletal network that regulates mitochondrial function under healthy conditions, but participates in the progression of hypertrophic cardiomyopathy pathophysiology resulting from sarcomeric gene mutations. Importantly, we pinpoint key 'linker' sites in this schema that may represent potential therapeutic targets.
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5
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Hool LC. Elucidating the role of the L-type calcium channel in excitability and energetics in the heart: The ISHR 2020 Research Achievement Award Lecture. J Mol Cell Cardiol 2022; 172:100-108. [PMID: 36041287 DOI: 10.1016/j.yjmcc.2022.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/31/2022] [Accepted: 08/08/2022] [Indexed: 12/14/2022]
Abstract
Cardiovascular disease continues to be the leading health burden worldwide and with the rising rates in obesity and type II diabetes and ongoing effects of long COVID, it is anticipated that the burden of cardiovascular morbidity and mortality will increase. Calcium is essential to cardiac excitation and contraction. The main route for Ca2+ influx is the L-type Ca2+ channel (Cav1.2) and embryos that are homozygous null for the Cav1.2 gene are lethal at day 14 postcoitum. Acute changes in Ca2+ influx through the channel contribute to arrhythmia and sudden death, and chronic increases in intracellular Ca2+ contribute to pathological hypertrophy and heart failure. We use a multidisciplinary approach to study the regulation of the channel from the molecular level through to in vivo CRISPR mutant animal models. Here we describe some examples of our work from over 2 decades studying the role of the channel under physiological and pathological conditions. Our single channel analysis of purified human Cav1.2 protein in proteoliposomes has contributed to understanding direct molecular regulation of the channel including identifying the critical serine involved in the "fight or flight" response. Using the same approach we identified the cysteine responsible for altered function during oxidative stress. Chronic activation of the L-type Ca2+ channel during oxidative stress occurs as a result of persistent glutathionylation of the channel that contributes to the development of hypertrophy. We describe for the first time that activation of the channel alters mitochondrial function (and energetics) on a beat-to-beat basis via movement of cytoskeletal proteins. In translational studies we have used this response to "report" mitochondrial function in models of cardiomyopathy and to test efficacy of novel therapies to prevent cardiomyopathy.
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Affiliation(s)
- Livia C Hool
- School of Human Sciences, University of Western Australia, Crawley, WA, Australia; Victor Chang Cardiac Research Institute, Sydney, NSW, Australia.
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Lozhkin A, Vendrov AE, Ramos-Mondragón R, Canugovi C, Stevenson MD, Herron TJ, Hummel SL, Figueroa CA, Bowles DE, Isom LL, Runge MS, Madamanchi NR. Mitochondrial oxidative stress contributes to diastolic dysfunction through impaired mitochondrial dynamics. Redox Biol 2022; 57:102474. [PMID: 36183542 PMCID: PMC9530618 DOI: 10.1016/j.redox.2022.102474] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/11/2022] [Indexed: 11/25/2022] Open
Abstract
Diastolic dysfunction (DD) underlies heart failure with preserved ejection fraction (HFpEF), a clinical syndrome associated with aging that is becoming more prevalent. Despite extensive clinical studies, no effective treatment exists for HFpEF. Recent findings suggest that oxidative stress contributes to the pathophysiology of DD, but molecular mechanisms underpinning redox-sensitive cardiac remodeling in DD remain obscure. Using transgenic mice with mitochondria-targeted NOX4 overexpression (Nox4TG618) as a model, we demonstrate that NOX4-dependent mitochondrial oxidative stress induces DD in mice as measured by increased E/E', isovolumic relaxation time, Tau Glantz and reduced dP/dtmin while EF is preserved. In Nox4TG618 mice, fragmentation of cardiomyocyte mitochondria, increased DRP1 phosphorylation, decreased expression of MFN2, and a higher percentage of apoptotic cells in the myocardium are associated with lower ATP-driven and maximal mitochondrial oxygen consumption rates, a decrease in respiratory reserve, and a decrease in citrate synthase and Complex I activities. Transgenic mice have an increased concentration of TGFβ and osteopontin in LV lysates, as well as MCP-1 in plasma, which correlates with a higher percentage of LV myocardial periostin- and ACTA2-positive cells compared with wild-type mice. Accordingly, the levels of ECM as measured by Picrosirius Red staining as well as interstitial deposition of collagen I are elevated in the myocardium of Nox4TG618 mice. The LV tissue of Nox4TG618 mice also exhibited increased ICaL current, calpain 2 expression, and altered/disrupted Z-disc structure. As it pertains to human pathology, similar changes were found in samples of LV from patients with DD. Finally, treatment with GKT137831, a specific NOX1 and NOX4 inhibitor, or overexpression of mCAT attenuated myocardial fibrosis and prevented DD in the Nox4TG618 mice. Together, our results indicate that mitochondrial oxidative stress contributes to DD by causing mitochondrial dysfunction, impaired mitochondrial dynamics, increased synthesis of pro-inflammatory and pro-fibrotic cytokines, activation of fibroblasts, and the accumulation of extracellular matrix, which leads to interstitial fibrosis and passive stiffness of the myocardium. Further, mitochondrial oxidative stress increases cardiomyocyte Ca2+ influx, which worsens CM relaxation and raises the LV filling pressure in conjunction with structural proteolytic damage.
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Affiliation(s)
- Andrey Lozhkin
- 1150 West Medical Center Drive, 7200 Medical Science Research Building III, Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, 48019, USA
| | - Aleksandr E Vendrov
- 1150 West Medical Center Drive, 7200 Medical Science Research Building III, Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, 48019, USA
| | - R Ramos-Mondragón
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Chandrika Canugovi
- 1150 West Medical Center Drive, 7200 Medical Science Research Building III, Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, 48019, USA
| | - Mark D Stevenson
- 1150 West Medical Center Drive, 7200 Medical Science Research Building III, Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, 48019, USA
| | - Todd J Herron
- Frankel Cardiovascular Regeneration Core Laboratory, Ann Arbor, MI, 48109, USA
| | - Scott L Hummel
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, 48109, USA; Ann Arbor Veterans Affairs Health System, Ann Arbor, MI, USA
| | - C Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Dawn E Bowles
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA; Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Marschall S Runge
- 1150 West Medical Center Drive, 7200 Medical Science Research Building III, Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, 48019, USA
| | - Nageswara R Madamanchi
- 1150 West Medical Center Drive, 7200 Medical Science Research Building III, Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, 48019, USA.
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Zampese E, Wokosin DL, Gonzalez-Rodriguez P, Guzman JN, Tkatch T, Kondapalli J, Surmeier WC, D’Alessandro KB, De Stefani D, Rizzuto R, Iino M, Molkentin JD, Chandel NS, Schumacker PT, Surmeier DJ. Ca 2+ channels couple spiking to mitochondrial metabolism in substantia nigra dopaminergic neurons. SCIENCE ADVANCES 2022; 8:eabp8701. [PMID: 36179023 PMCID: PMC9524841 DOI: 10.1126/sciadv.abp8701] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/12/2022] [Indexed: 05/08/2023]
Abstract
How do neurons match generation of adenosine triphosphate by mitochondria to the bioenergetic demands of regenerative activity? Although the subject of speculation, this coupling is still poorly understood, particularly in neurons that are tonically active. To help fill this gap, pacemaking substantia nigra dopaminergic neurons were studied using a combination of optical, electrophysiological, and molecular approaches. In these neurons, spike-activated calcium (Ca2+) entry through Cav1 channels triggered Ca2+ release from the endoplasmic reticulum, which stimulated mitochondrial oxidative phosphorylation through two complementary Ca2+-dependent mechanisms: one mediated by the mitochondrial uniporter and another by the malate-aspartate shuttle. Disrupting either mechanism impaired the ability of dopaminergic neurons to sustain spike activity. While this feedforward control helps dopaminergic neurons meet the bioenergetic demands associated with sustained spiking, it is also responsible for their elevated oxidant stress and possibly to their decline with aging and disease.
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Affiliation(s)
- Enrico Zampese
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - David L. Wokosin
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Patricia Gonzalez-Rodriguez
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Jaime N. Guzman
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Tatiana Tkatch
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Jyothisri Kondapalli
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - William C. Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Karis B. D’Alessandro
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Masamitsu Iino
- Department of Physiology, Nihon University School of Medicine, 30-1, Oyaguchi Kami-cho, Itabashi-ku, Tokyo 173-8610, Japan
| | - Jeffery D. Molkentin
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Navdeep S. Chandel
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Paul T. Schumacker
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - D. James Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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8
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Henderson MX, Henrich MT, Geibl FF, Oertel WH, Brundin P, Surmeier DJ. The roles of connectivity and neuronal phenotype in determining the pattern of α-synuclein pathology in Parkinson's disease. Neurobiol Dis 2022; 168:105687. [PMID: 35283326 PMCID: PMC9610381 DOI: 10.1016/j.nbd.2022.105687] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/31/2022] [Accepted: 03/07/2022] [Indexed: 12/15/2022] Open
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder, and motor dysfunction has been attributed to loss of dopaminergic neurons. However, motor dysfunction is only one of many symptoms experienced by patients. A neuropathological hallmark of PD is intraneuronal protein aggregates called Lewy pathology (LP). Neuropathological staging studies have shown that dopaminergic neurons are only one of the many cell types prone to manifest LP. Progressive appearance of LP in multiple brain regions, as well as peripheral nerves, has led to the popular hypothesis that LP and misfolded forms of one of its major components - α-synuclein (aSYN) - can spread through synaptically connected circuits. However, not all brain regions or neurons within connected circuits develop LP, suggesting that cell autonomous factors modulate the development of pathology. Here, we review studies about how LP develops and progressively engages additional brain regions. We focus on how connectivity constrains progression and discuss cell autonomous factors that drive pathology development. We propose a mixed model of cell autonomous factors and trans-synaptic spread as mediators of pathology progression and put forward this model as a framework for future experiments exploring PD pathophysiology.
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Affiliation(s)
- Michael X Henderson
- Parkinson's Disease Center, Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, United States of America.
| | - Martin T Henrich
- Department of Neurology, Philipps-University Marburg, Marburg 35043, Germany; Department of Psychiatry and Psychotherapy, Philipps-University Marburg, Marburg 35043, Germany; Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Fanni F Geibl
- Department of Neurology, Philipps-University Marburg, Marburg 35043, Germany; Department of Psychiatry and Psychotherapy, Philipps-University Marburg, Marburg 35043, Germany; Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Wolfgang H Oertel
- Department of Neurology, Philipps-University Marburg, Marburg 35043, Germany
| | - Patrik Brundin
- Parkinson's Disease Center, Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, United States of America
| | - D James Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
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Mitochondrial Ca 2+ Homeostasis: Emerging Roles and Clinical Significance in Cardiac Remodeling. Int J Mol Sci 2022; 23:ijms23063025. [PMID: 35328444 PMCID: PMC8954803 DOI: 10.3390/ijms23063025] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 01/27/2023] Open
Abstract
Mitochondria are the sites of oxidative metabolism in eukaryotes where the metabolites of sugars, fats, and amino acids are oxidized to harvest energy. Notably, mitochondria store Ca2+ and work in synergy with organelles such as the endoplasmic reticulum and extracellular matrix to control the dynamic balance of Ca2+ concentration in cells. Mitochondria are the vital organelles in heart tissue. Mitochondrial Ca2+ homeostasis is particularly important for maintaining the physiological and pathological mechanisms of the heart. Mitochondrial Ca2+ homeostasis plays a key role in the regulation of cardiac energy metabolism, mechanisms of death, oxygen free radical production, and autophagy. The imbalance of mitochondrial Ca2+ balance is closely associated with cardiac remodeling. The mitochondrial Ca2+ uniporter (mtCU) protein complex is responsible for the uptake and release of mitochondrial Ca2+ and regulation of Ca2+ homeostasis in mitochondria and consequently, in cells. This review summarizes the mechanisms of mitochondrial Ca2+ homeostasis in physiological and pathological cardiac remodeling and the regulatory effects of the mitochondrial calcium regulatory complex on cardiac energy metabolism, cell death, and autophagy, and also provides the theoretical basis for mitochondrial Ca2+ as a novel target for the treatment of cardiovascular diseases.
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10
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Fernandez Rico C, Konate K, Josse E, Nargeot J, Barrère-Lemaire S, Boisguérin P. Therapeutic Peptides to Treat Myocardial Ischemia-Reperfusion Injury. Front Cardiovasc Med 2022; 9:792885. [PMID: 35252383 PMCID: PMC8891520 DOI: 10.3389/fcvm.2022.792885] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 01/07/2022] [Indexed: 12/13/2022] Open
Abstract
Cardiovascular diseases (CVD) including acute myocardial infarction (AMI) rank first in worldwide mortality and according to the World Health Organization (WHO), they will stay at this rank until 2030. Prompt revascularization of the occluded artery to reperfuse the myocardium is the only recommended treatment (by angioplasty or thrombolysis) to decrease infarct size (IS). However, despite beneficial effects on ischemic lesions, reperfusion leads to ischemia-reperfusion (IR) injury related mainly to apoptosis. Improvement of revascularization techniques and patient care has decreased myocardial infarction (MI) mortality however heart failure (HF) morbidity is increasing, contributing to the cost-intense worldwide HF epidemic. Currently, there is no treatment for reperfusion injury despite promising results in animal models. There is now an obvious need to develop new cardioprotective strategies to decrease morbidity/mortality of CVD, which is increasing due to the aging of the population and the rising prevalence rates of diabetes and obesity. In this review, we will summarize the different therapeutic peptides developed or used focused on the treatment of myocardial IR injury (MIRI). Therapeutic peptides will be presented depending on their interacting mechanisms (apoptosis, necroptosis, and inflammation) reported as playing an important role in reperfusion injury following myocardial ischemia. The search and development of therapeutic peptides have become very active, with increasing numbers of candidates entering clinical trials. Their optimization and their potential application in the treatment of patients with AMI will be discussed.
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Affiliation(s)
- Carlota Fernandez Rico
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- Laboratory of Excellence Ion Channel Science and Therapeutics, Valbonne, France
| | - Karidia Konate
- PHYMEDEXP, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Emilie Josse
- PHYMEDEXP, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Joël Nargeot
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- Laboratory of Excellence Ion Channel Science and Therapeutics, Valbonne, France
| | - Stéphanie Barrère-Lemaire
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
- Laboratory of Excellence Ion Channel Science and Therapeutics, Valbonne, France
| | - Prisca Boisguérin
- PHYMEDEXP, Université de Montpellier, CNRS, INSERM, Montpellier, France
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11
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Wu AJ, Tong BCK, Huang AS, Li M, Cheung KH. Mitochondrial Calcium Signaling as a Therapeutic Target for Alzheimer's Disease. Curr Alzheimer Res 2021; 17:329-343. [PMID: 31820698 DOI: 10.2174/1567205016666191210091302] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 10/17/2019] [Accepted: 12/09/2019] [Indexed: 11/22/2022]
Abstract
Mitochondria absorb calcium (Ca2+) at the expense of the electrochemical gradient generated during respiration. The influx of Ca2+ into the mitochondrial matrix helps maintain metabolic function and results in increased cytosolic Ca2+ during intracellular Ca2+ signaling. Mitochondrial Ca2+ homeostasis is tightly regulated by proteins located in the inner and outer mitochondrial membranes and by the cross-talk with endoplasmic reticulum Ca2+ signals. Increasing evidence indicates that mitochondrial Ca2+ overload is a pathological phenotype associated with Alzheimer's Disease (AD). As intracellular Ca2+ dysregulation can be observed before the appearance of typical pathological hallmarks of AD, it is believed that mitochondrial Ca2+ overload may also play an important role in AD etiology. The high mitochondrial Ca2+ uptake can easily compromise neuronal functions and exacerbate AD progression by impairing mitochondrial respiration, increasing reactive oxygen species formation and inducing apoptosis. Additionally, mitochondrial Ca2+ overload can damage mitochondrial recycling via mitophagy. This review will discuss the molecular players involved in mitochondrial Ca2+ dysregulation and the pharmacotherapies that target this dysregulation. As most of the current AD therapeutics are based on amyloidopathy, tauopathy, and the cholinergic hypothesis, they achieve only symptomatic relief. Thus, determining how to reestablish mitochondrial Ca2+ homeostasis may aid in the development of novel AD therapeutic interventions.
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Affiliation(s)
- Aston J Wu
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - Benjamin C-K Tong
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - Alexis S Huang
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - Min Li
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
| | - King-Ho Cheung
- School of Chinese Medicine, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China.,Mr. and Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Kowloon, Hong Kong, China
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12
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Pickel S, Cruz-Garcia Y, Bandleon S, Barkovits K, Heindl C, Völker K, Abeßer M, Pfeiffer K, Schaaf A, Marcus K, Eder-Negrin P, Kuhn M, Miranda-Laferte E. The β 2-Subunit of Voltage-Gated Calcium Channels Regulates Cardiomyocyte Hypertrophy. Front Cardiovasc Med 2021; 8:704657. [PMID: 34307509 PMCID: PMC8292724 DOI: 10.3389/fcvm.2021.704657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/09/2021] [Indexed: 12/16/2022] Open
Abstract
L-type voltage-gated calcium channels (LTCCs) regulate crucial physiological processes in the heart. They are composed of the Cavα1 pore-forming subunit and the accessory subunits Cavβ, Cavα2δ, and Cavγ. Cavβ is a cytosolic protein that regulates channel trafficking and activity, but it also exerts other LTCC-independent functions. Cardiac hypertrophy, a relevant risk factor for the development of congestive heart failure, depends on the activation of calcium-dependent pro-hypertrophic signaling cascades. Here, by using shRNA-mediated Cavβ silencing, we demonstrate that Cavβ2 downregulation enhances α1-adrenergic receptor agonist-induced cardiomyocyte hypertrophy. We report that a pool of Cavβ2 is targeted to the nucleus in cardiomyocytes and that the expression of this nuclear fraction decreases during in vitro and in vivo induction of cardiac hypertrophy. Moreover, the overexpression of nucleus-targeted Cavβ2 in cardiomyocytes inhibits in vitro-induced hypertrophy. Quantitative proteomic analyses showed that Cavβ2 knockdown leads to changes in the expression of diverse myocyte proteins, including reduction of calpastatin, an endogenous inhibitor of the calcium-dependent protease calpain. Accordingly, Cavβ2-downregulated cardiomyocytes had a 2-fold increase in calpain activity as compared to control cells. Furthermore, inhibition of calpain activity in Cavβ2-downregulated cells abolished the enhanced α1-adrenergic receptor agonist-induced hypertrophy observed in these cells. Our findings indicate that in cardiomyocytes, a nuclear pool of Cavβ2 participates in cellular functions that are independent of LTCC activity. They also indicate that a downregulation of nuclear Cavβ2 during cardiomyocyte hypertrophy promotes the activation of calpain-dependent hypertrophic pathways.
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Affiliation(s)
- Simone Pickel
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | | | - Sandra Bandleon
- Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Katalin Barkovits
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,Medical Proteome Analysis, Center for Proteindiagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany
| | - Cornelia Heindl
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Katharina Völker
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Marco Abeßer
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Kathy Pfeiffer
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,Medical Proteome Analysis, Center for Proteindiagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany
| | - Alice Schaaf
- Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Katrin Marcus
- Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany.,Medical Proteome Analysis, Center for Proteindiagnostics (PRODI), Ruhr-University Bochum, Bochum, Germany
| | - Petra Eder-Negrin
- Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Michaela Kuhn
- Institute of Physiology, University of Würzburg, Würzburg, Germany.,Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Erick Miranda-Laferte
- Institute of Physiology, University of Würzburg, Würzburg, Germany.,Institut für Biologische Informationsprozesse, Molekular- und Zellphysiologie (IBI-1), Forschungszentrum Jülich, Jülich, Germany
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13
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Ramaccini D, Montoya-Uribe V, Aan FJ, Modesti L, Potes Y, Wieckowski MR, Krga I, Glibetić M, Pinton P, Giorgi C, Matter ML. Mitochondrial Function and Dysfunction in Dilated Cardiomyopathy. Front Cell Dev Biol 2021; 8:624216. [PMID: 33511136 PMCID: PMC7835522 DOI: 10.3389/fcell.2020.624216] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/16/2020] [Indexed: 12/14/2022] Open
Abstract
Cardiac tissue requires a persistent production of energy in order to exert its pumping function. Therefore, the maintenance of this function relies on mitochondria that represent the “powerhouse” of all cardiac activities. Mitochondria being one of the key players for the proper functioning of the mammalian heart suggests continual regulation and organization. Mitochondria adapt to cellular energy demands via fusion-fission events and, as a proof-reading ability, undergo mitophagy in cases of abnormalities. Ca2+ fluxes play a pivotal role in regulating all mitochondrial functions, including ATP production, metabolism, oxidative stress balance and apoptosis. Communication between mitochondria and others organelles, especially the sarcoplasmic reticulum is required for optimal function. Consequently, abnormal mitochondrial activity results in decreased energy production leading to pathological conditions. In this review, we will describe how mitochondrial function or dysfunction impacts cardiac activities and the development of dilated cardiomyopathy.
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Affiliation(s)
- Daniela Ramaccini
- University of Hawaii Cancer Center, Honolulu, HI, United States.,Department of Medical Sciences, University of Ferrara, Ferrara, Italy.,Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy
| | | | - Femke J Aan
- University of Hawaii Cancer Center, Honolulu, HI, United States
| | - Lorenzo Modesti
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy.,Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy
| | - Yaiza Potes
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Irena Krga
- Center of Research Excellence in Nutrition and Metabolism, Institute for Medical Research, University of Belgrade, Belgrade, Serbia
| | - Marija Glibetić
- Center of Research Excellence in Nutrition and Metabolism, Institute for Medical Research, University of Belgrade, Belgrade, Serbia
| | - Paolo Pinton
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy.,Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy.,Maria Cecilia Hospital, GVM Care & Research, Cotignola, Italy
| | - Carlotta Giorgi
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy.,Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy
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14
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Mechanisms Underlying the Cardioprotection of YangXinDingJi Capsule against Myocardial Ischemia in Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:8539148. [PMID: 33281916 PMCID: PMC7685838 DOI: 10.1155/2020/8539148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/26/2020] [Accepted: 10/20/2020] [Indexed: 11/18/2022]
Abstract
Background YangXinDingJi (YXDJ) capsule is one of traditional Chinese medicines (TCMs) derived from Zhigancao decoction, which is usually used for the treatment of cardiovascular disease in China. Aim of the Study. Cardiovascular events are one of the leading causes of death worldwide. Myocardial ischemia (MI) severely reduces myocyte longevity and function. The YangXinDingJi (YXDJ) capsule has been used in the treatment of clinical cardiac disease in China. Nevertheless, the underlying cellular mechanisms for the benefits to heart function resulting from the use of this capsule are still unclear. The aim of this study was to evaluate the protective effects of the YXDJ on isoprenaline-induced MI in rats and to clarify its underlying myocardial protective mechanisms based on L-type calcium channels and myocardial contractility. Materials and Methods Rats were randomly divided into five groups with ten rats in each group: (1) control; (2) ISO-induced model; (3) high-dose YXDJ (2.8 g/kg/day intraperitoneally for five days), (4) low-dose YXDJ (1.4 g/kg/day for five days); and (5) verapamil (n = 10 in each group). Isoproterenol (ISO) was injected subcutaneously for two consecutive days to induce the rat model of MI. Heart and biochemical parameters were obtained. The patch-clamp technique was used to observe the regulatory effects of YXDJ on the L-type calcium current (ICa-L) in isolated cardiomyocytes. An IonOptix MyoCam detection system was used to observe the contractility of YXDJ on isolated cardiomyocytes. Results YXDJ caused a significant improvement in pathological heart morphology and alleviated oxidative stress and inflammatory responses. Exposure to YXDJ caused a decrease in blockade of ICa-L in a concentration-dependent manner. Conclusions The results indicate that YXDJ significantly inhibited inflammatory cytokine expressions, oxidative stress, and L-type Ca2+ channels, and decreased contractility in isolated rat cardiomyocytes. These findings may be relevant to the cardioprotective efficacy of YXDJ.
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15
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Wang F, Meng TG, Li J, Hou Y, Luo SM, Schatten H, Sun QY, Ou XH. Mitochondrial Ca 2 + Is Related to Mitochondrial Activity and Dynamic Events in Mouse Oocytes. Front Cell Dev Biol 2020; 8:585932. [PMID: 33195238 PMCID: PMC7652752 DOI: 10.3389/fcell.2020.585932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/22/2020] [Indexed: 11/23/2022] Open
Abstract
Mitochondrial energy insufficiency is strongly associated with oocyte activation disorders. Ca2+, especially that in the mitochondrial matrix, plays a pivotal role in mitochondrial energy supplementation, but the underlying mechanisms are still only poorly understood. An encoded mitochondrial matrix Ca2+ probe (Mt-GCaMP6s) was introduced to observe mitochondrial Ca2+ ([Ca2+]m) dynamic changes during oocyte maturation and activation. We found that active mitochondria surrounding the nucleus showed a higher [Ca2+]m than those distributed in the cortex during oocyte maturation. During oocyte partheno-activation, the patterns of Ca2+ dynamic changes were synchronous in the cytoplasm and mitochondria. Such higher concentration of mitochondrial matrix Ca2+ was closely related to the distribution of mitochondrial calcium uptake (MICU) protein. We further showed that higher [Ca2+]m mitochondria around the chromosomes in oocytes might have a potential role in stimulating mitochondrial energy for calmodulin-responsive oocyte spindle formation, while synchronizing Ca2+ functions in the cytoplasm and nuclear area are important for oocyte activation.
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Affiliation(s)
- Feng Wang
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Tie-Gang Meng
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Jian Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Yi Hou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Shi-Ming Luo
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, United States
| | - Qing-Yuan Sun
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xiang-Hong Ou
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
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16
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Zampese E, Surmeier DJ. Calcium, Bioenergetics, and Parkinson's Disease. Cells 2020; 9:cells9092045. [PMID: 32911641 PMCID: PMC7564460 DOI: 10.3390/cells9092045] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
Degeneration of substantia nigra (SN) dopaminergic (DAergic) neurons is responsible for the core motor deficits of Parkinson’s disease (PD). These neurons are autonomous pacemakers that have large cytosolic Ca2+ oscillations that have been linked to basal mitochondrial oxidant stress and turnover. This review explores the origin of Ca2+ oscillations and their role in the control of mitochondrial respiration, bioenergetics, and mitochondrial oxidant stress.
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17
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Solomon T, Filipovska A, Hool L, Viola H. Preventative therapeutic approaches for hypertrophic cardiomyopathy. J Physiol 2020; 599:3495-3512. [PMID: 32822065 PMCID: PMC8359240 DOI: 10.1113/jp279410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/06/2020] [Indexed: 11/08/2022] Open
Abstract
Sarcomeric gene mutations are associated with the development of hypertrophic cardiomyopathy (HCM). Current drug therapeutics for HCM patients are effective in relieving symptoms, but do not prevent or reverse disease progression. Moreover, due to heterogeneity in the clinical manifestations of the disease, patients experience variable outcomes in response to therapeutics. Mechanistically, alterations in calcium handling, sarcomeric disorganization, energy metabolism and contractility participate in HCM disease progression. While some similarities exist, each mutation appears to lead to mutation‐specific pathophysiology. Furthermore, these alterations may precede or proceed development of the pathology. This review assesses the efficacy of HCM therapeutics from studies performed in animal models of HCM and human clinical trials. Evidence suggests that a preventative rather than corrective therapeutic approach may be more efficacious in the treatment of HCM. In addition, a clear understanding of mutation‐specific mechanisms may assist in informing the most effective therapeutic mode of action.
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Affiliation(s)
- Tanya Solomon
- School of Human Sciences, University of Western Australia, Crawley, Western Australia, Australia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia.,ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia.,Centre for Medical Research, University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia.,Telethon Kids Institute, Perth Children's Hospital, Nedlands, Western Australia, Australia.,School of Molecular Sciences, University of Western Australia, Crawley, Western Australia, Australia
| | - Livia Hool
- School of Human Sciences, University of Western Australia, Crawley, Western Australia, Australia.,Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Helena Viola
- School of Human Sciences, University of Western Australia, Crawley, Western Australia, Australia
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18
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Characterization and validation of a preventative therapy for hypertrophic cardiomyopathy in a murine model of the disease. Proc Natl Acad Sci U S A 2020; 117:23113-23124. [PMID: 32859761 PMCID: PMC7502707 DOI: 10.1073/pnas.2002976117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hypertrophic cardiomyopathy affects 1:500 of the general population. Current drug therapy is used to manage symptoms in patients. There is an unmet need for treatments that can prevent the cardiomyopathy. Here we identify biomarkers of hypertrophic cardiomyopathy resulting from causing cardiac troponin I mutation Gly203Ser, and present a safe, nontoxic, preventative approach for the treatment of associated cardiomyopathy. Currently there is an unmet need for treatments that can prevent hypertrophic cardiomyopathy (HCM). Using a murine model we previously identified that HCM causing cardiac troponin I mutation Gly203Ser (cTnI-G203S) is associated with increased mitochondrial metabolic activity, consistent with the human condition. These alterations precede development of the cardiomyopathy. Here we examine the efficacy of in vivo treatment of cTnI-G203S mice with a peptide derived against the α-interaction domain of the cardiac L-type calcium channel (AID-TAT) on restoring mitochondrial metabolic activity, and preventing HCM. cTnI-G203S or age-matched wt mice were treated with active or inactive AID-TAT. Following treatment, targeted metabolomics was utilized to evaluate myocardial substrate metabolism. Cardiac myocyte mitochondrial metabolic activity was assessed as alterations in mitochondrial membrane potential and flavoprotein oxidation. Cardiac morphology and function were examined using echocardiography. Cardiac uptake was assessed using an in vivo multispectral imaging system. We identified alterations in six biochemical intermediates in cTnI-G203S hearts consistent with increased anaplerosis. We also reveal that AID-TAT treatment of precardiomyopathic cTnI-G203S mice, but not mice with established cardiomyopathy, restored cardiac myocyte mitochondrial membrane potential and flavoprotein oxidation, and prevented myocardial hypertrophy. Importantly, AID-TAT was rapidly targeted to the heart, and not retained by the liver or kidneys. Overall, we identify biomarkers of HCM resulting from the cTnI mutation Gly203Ser, and present a safe, preventative therapy for associated cardiomyopathy. Utilizing AID-TAT to modulate cardiac metabolic activity may be beneficial in preventing HCM in “at risk” patients with identified Gly203Ser gene mutations.
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19
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Viola HM, Shah AA, Kretzmann JA, Evans CW, Norret M, Iyer KS, Hool LC. A dendronized polymer variant that facilitates safe delivery of a calcium channel antagonist to the heart. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2020; 29:102264. [PMID: 32659322 DOI: 10.1016/j.nano.2020.102264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/29/2020] [Accepted: 07/02/2020] [Indexed: 11/27/2022]
Abstract
Therapeutic approaches for myocardial ischemia-reperfusion injury (MI) have been ineffective due to limited bioavailability and poor specificity. We have previously shown that a peptide that targets the α-interaction domain of the cardiac L-type calcium channel (AID-peptide) attenuates MI when tethered to transactivator of transcription sequence (TAT) or spherical nanoparticles. However some reservations remain regarding use of these delivery platforms due to the relationship with human immunodeficiency virus, off-target effects and toxicity. Here we investigate the use of linear dendronized polymers (denpols) to deliver AID-peptide as a potential MI therapy using in vitro, ex vivo and in vivo models. Optimized denpol-complexed AID-peptide facilitated in vitro cardiac uptake of AID-peptide, and reduced MI. Maximal in vivo cardiac uptake was achieved within the 2 h therapeutic time window for acute myocardial infarction. Importantly, optimized denpol-complexed AID-peptide was not toxic. This platform may represent an alternative therapeutic approach for the prevention of MI.
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Affiliation(s)
- Helena M Viola
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA, Australia
| | - Ashay A Shah
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA, Australia
| | - Jessica A Kretzmann
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Cameron W Evans
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Marck Norret
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - K Swaminathan Iyer
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Livia C Hool
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA, Australia; Victor Chang Cardiac Research Institute, Sydney, NSW, Australia.
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20
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Wang F, Li A, Li QN, Fan LH, Wang ZB, Meng TG, Hou Y, Schatten H, Sun QY, Ou XH. Effects of mitochondria-associated Ca 2+ transporters suppression on oocyte activation. Cell Biochem Funct 2020; 39:248-257. [PMID: 32643225 DOI: 10.1002/cbf.3571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/05/2020] [Accepted: 06/07/2020] [Indexed: 12/14/2022]
Abstract
Oocyte activation deficiency leads to female infertility. [Ca2+ ]i oscillations are required for mitochondrial energy supplement transition from the resting to the excited state, but the underlying mechanisms are still very little known. Three mitochondrial Ca2+ channels, Mitochondria Calcium Uniporter (MCU), Na+ /Ca2+ Exchanger (NCLX) and Voltage-dependent Ca2+ Channel (VDAC), were deactivated by inhibitors RU360, CGP37157 and Erastin, respectively. Both Erastin and CGP37157 inhibited mitochondrial activity significantly while attenuating [Ca2+ ]i and [Ca2+ ]m oscillations, which caused developmental block of pronuclear formation. Thus, NCLX and VDAC are two mitochondria-associated Ca2+ transporter proteins regulating oocyte activation, which may be used as potential targets to treat female infertility. SIGNIFICANCE OF THE STUDY: NCLX and VDAC are two mitochondria-associated Ca2+ transporter proteins regulating oocyte activation.
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Affiliation(s)
- Feng Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Ang Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qian-Nan Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Li-Hua Fan
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Zhen-Bo Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Tie-Gang Meng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Yi Hou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Qing-Yuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Xiang-Hong Ou
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
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21
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Gonzalez-Rodriguez P, Zampese E, Surmeier DJ. Selective neuronal vulnerability in Parkinson's disease. PROGRESS IN BRAIN RESEARCH 2020; 252:61-89. [PMID: 32247375 DOI: 10.1016/bs.pbr.2020.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease, disabling millions worldwide. Despite the imperative PD poses, at present, there is no cure or means of slowing progression. This gap is attributable to our incomplete understanding of the factors driving pathogenesis. Research over the past several decades suggests that both cell-autonomous and non-cell autonomous processes contribute to the neuronal dysfunction underlying PD symptoms. The thesis of this review is that an intersection of these processes governs the pattern of pathology in PD. Studies of substantia nigra pars compacta (SNc) dopaminergic neurons, whose loss is responsible for the core motor symptoms of PD, suggest that they have a combination of traits-a long, highly branched axon, autonomous activity, and elevated mitochondrial oxidant stress-that predispose them to non-cell autonomous drivers of pathogenesis, like misfolded forms of alpha-synuclein (α-SYN) and inflammation. The literature surrounding these issues will be briefly summarized, and the translational implications of an intersectional hypothesis of PD pathogenesis discussed.
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Affiliation(s)
| | - Enrico Zampese
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.
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22
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Anderson AJ, Jackson TD, Stroud DA, Stojanovski D. Mitochondria-hubs for regulating cellular biochemistry: emerging concepts and networks. Open Biol 2019; 9:190126. [PMID: 31387448 PMCID: PMC6731593 DOI: 10.1098/rsob.190126] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondria are iconic structures in biochemistry and cell biology, traditionally referred to as the powerhouse of the cell due to a central role in energy production. However, modern-day mitochondria are recognized as key players in eukaryotic cell biology and are known to regulate crucial cellular processes, including calcium signalling, cell metabolism and cell death, to name a few. In this review, we will discuss foundational knowledge in mitochondrial biology and provide snapshots of recent advances that showcase how mitochondrial function regulates other cellular responses.
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Affiliation(s)
- Alexander J Anderson
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Thomas D Jackson
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - David A Stroud
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Diana Stojanovski
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia
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23
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Oliveira RB, Petiz LL, Lim R, Lipski J, Gravina FS, Brichta AM, Callister RJ, Leão RN, Helden DF. Crosstalk between mitochondria, calcium channels and actin cytoskeleton modulates noradrenergic activity of locus coeruleus neurons. J Neurochem 2019; 149:471-487. [DOI: 10.1111/jnc.14692] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/22/2019] [Accepted: 02/28/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Ramatis B. Oliveira
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
- Health and Medical Research Group School of Medicine University of the Taquari Valley ‐ Univates Lajeado RS Brazil
- Bairro Universitário Lajeado RS Brazil
| | - Lyvia L. Petiz
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
- Brain Institute Federal University of Rio Grande do Norte Natal Brazil
| | - Rebecca Lim
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
| | - Janusz Lipski
- Faculty of Medical and Health Sciences University of Auckland Auckland New Zealand
| | - Fernanda S. Gravina
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
| | - Alan M. Brichta
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
| | - Robert J. Callister
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
| | - Richardson N. Leão
- Brain Institute Federal University of Rio Grande do Norte Natal Brazil
- The Beijer Laboratory for Gene and Neurosciences Department of Neuroscience Uppsala University Uppsala Sweden
| | - Dirk F. Helden
- School of Biomedical Sciences and Pharmacy University of Newcastle and Hunter Medical Research Institute Callaghan NSW Australia
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Viola HM, Hool LC. Impaired calcium handling and mitochondrial metabolic dysfunction as early markers of hypertrophic cardiomyopathy. Arch Biochem Biophys 2019; 665:166-174. [PMID: 30885674 DOI: 10.1016/j.abb.2019.03.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 02/07/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary myocardial disorder, characterised by myocyte remodeling, disorganisation of sarcomeric proteins, impaired energy metabolism and altered cardiac contractility. Gene mutations encoding cardiac contractile proteins account for 60% of HCM aetiology. Current drug therapy including L-type calcium channel antagonists, are used to manage symptoms in patients with overt HCM, but no treatment exists that can reverse or prevent the cardiomyopathy. Design of effective drug therapy will require a clear understanding of the early pathophysiological mechanisms of the disease. Numerous studies have investigated specific aspects of HCM pathophysiology. This review brings these findings together, in order to develop a holistic understanding of the early pathophysiological mechanisms of the disease. We focus on gene mutations in cardiac myosin binding protein-C, β-cardiac myosin heavy chain, cardiac troponin I, and cardiac troponin T, that comprise the majority of all HCM sarcomeric gene mutations. We find that although some similarities exist, each mutation leads to mutation-specific alterations in calcium handling, myofilament calcium sensitivity and mitochondrial metabolic function. This may contribute to the observed clinical phenotypic variability in sarcomeric-related HCM. An understanding of early mutation-specific mechanisms of the disease may provide useful markers of disease progression, and inform therapeutic design.
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Affiliation(s)
- Helena M Viola
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA, Australia
| | - Livia C Hool
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA, Australia; Victor Chang Cardiac Research Institute, Sydney, NSW, Australia.
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25
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Giorgi C, Marchi S, Pinton P. The machineries, regulation and cellular functions of mitochondrial calcium. Nat Rev Mol Cell Biol 2018; 19:713-730. [PMID: 30143745 DOI: 10.1038/s41580-018-0052-8] [Citation(s) in RCA: 494] [Impact Index Per Article: 82.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Calcium ions (Ca2+) are some of the most versatile signalling molecules, and they have many physiological functions, prominently including muscle contraction, neuronal excitability, cell migration and cell growth. By sequestering and releasing Ca2+, mitochondria serve as important regulators of cellular Ca2+. Mitochondrial Ca2+ also has other important functions, such as regulation of mitochondrial metabolism, ATP production and cell death. In recent years, identification of the molecular machinery regulating mitochondrial Ca2+ accumulation and efflux has expanded the number of (patho)physiological conditions that rely on mitochondrial Ca2+ homeostasis. Thus, expanding the understanding of the mechanisms of mitochondrial Ca2+ regulation and function in different cell types is an important task in biomedical research, which offers the possibility of targeting mitochondrial Ca2+ machinery for the treatment of several disorders.
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Affiliation(s)
- Carlotta Giorgi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Saverio Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy. .,Maria Cecilia Hospital, GVM Care and Research, Cotignola, Ravenna, Italy.
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26
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Viola HM, Johnstone VP, Adams AM, Fletcher S, Hool LC. A Morpholino Oligomer Therapy Regime That Restores Mitochondrial Function and Prevents mdx Cardiomyopathy. JACC Basic Transl Sci 2018; 3:391-402. [PMID: 30062225 PMCID: PMC6059013 DOI: 10.1016/j.jacbts.2018.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 03/15/2018] [Indexed: 02/07/2023]
Abstract
Current clinical trials demonstrate Duchenne muscular dystrophy (DMD) patients receiving phosphorodiamidate morpholino oligomer (PMO) therapy exhibit improved ambulation and stable pulmonary function; however, cardiac abnormalities remain. Utilizing the same PMO chemistry as current clinical trials, we have identified a non-toxic PMO treatment regimen that restores metabolic activity and prevents DMD cardiomyopathy. We propose that a treatment regimen of this nature may have the potential to significantly improve morbidity and mortality from DMD by improving ambulation, stabilizing pulmonary function, and preventing the development of cardiomyopathy.
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Key Words
- DMD, Duchenne muscular dystrophy
- ICa-L, L-type Ca2+ channel
- JC-1, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide
- L-type calcium channels
- PMO, phosphorodiamidate morpholino oligomer
- RT-PCR, reverse transcriptase polymerase chain reaction
- cardiomyopathy
- mdx, murine model of Duchenne muscular dystrophy
- mitochondria
- wt, wild type
- Ψm, mitochondrial membrane potential
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Affiliation(s)
- Helena M. Viola
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Victoria P.A. Johnstone
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Abbie M. Adams
- Centre for Comparative Genomics, Murdoch University, Murdoch, Western Australia, Australia
| | - Susan Fletcher
- Centre for Comparative Genomics, Murdoch University, Murdoch, Western Australia, Australia
- Perron Institute for Neuroscience and Translational Science, and Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Livia C. Hool
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
- Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
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27
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Gonzalez JP, Ramachandran J, Himelman E, Badr MA, Kang C, Nouet J, Fefelova N, Xie LH, Shirokova N, Contreras JE, Fraidenraich D. Normalization of connexin 43 protein levels prevents cellular and functional signs of dystrophic cardiomyopathy in mice. Neuromuscul Disord 2018; 28:361-372. [PMID: 29477453 DOI: 10.1016/j.nmd.2018.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 11/20/2017] [Accepted: 01/25/2018] [Indexed: 11/29/2022]
Abstract
Duchenne muscular dystrophy (DMD) associated cardiomyopathy remains incurable. Connexin 43 (Cx43) is upregulated and remodeled in the hearts of mdx mice, a mouse model of DMD. Hearts from Wild Type, mdx, and mdx:Cx43(+/-) mice were studied before (4-6 months) and after (10-15 months) the onset of cardiomyopathy to assess the impact of decreasing Cx43 levels on cardiac pathology in dystrophic mice. Increased connexin 43 protein levels in mdx hearts were not observed in mdx:Cx43(+/-) hearts. Cx43 remodeling in mdx hearts was attenuated in mdx:Cx43(+/-) hearts. At time-point 4-6 months, isolated cardiomyocytes from mdx hearts displayed enhanced ethidium bromide uptake, augmented intracellular calcium signals and increased production of reactive oxygen species. These pathological features were improved in mdx:Cx43(+/-) cardiomyocytes. Isoproterenol-challenged mdx:Cx43(+/-) mice did not show arrhythmias or acute lethality observed in mdx mice. Likewise, isoproterenol-challenged mdx:Cx43(+/-) isolated hearts were also protected from arrhythmogenesis. At time-point 10-15 months, mdx:Cx43(+/-) mice showed decreased cardiac fibrosis and improved ventricular function, relative to mdx mice. These results suggest that normalization of connexin 43 protein levels in mdx mice reduces overall cardiac pathology.
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Affiliation(s)
- J Patrick Gonzalez
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Jayalakshmi Ramachandran
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Eric Himelman
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Myriam A Badr
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Chifei Kang
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Julie Nouet
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Nadezhda Fefelova
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Natalia Shirokova
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA.
| | - Jorge E Contreras
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA.
| | - Diego Fraidenraich
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA.
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28
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Kurz FT, Aon MA, O'Rourke B, Armoundas AA. Assessing Spatiotemporal and Functional Organization of Mitochondrial Networks. Methods Mol Biol 2018; 1782:383-402. [PMID: 29851013 PMCID: PMC7003721 DOI: 10.1007/978-1-4939-7831-1_23] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
The functional and spatiotemporal organization of mitochondrial redox signaling networks can be studied in detail in cardiac myocytes and neurons by assessing the time-resolved signaling traits of their individual mitochondrial components. Perturbations of the mitochondrial network through oxidative stress can lead to coordinated, cluster-bound behavior in the form of synchronized limit-cycle oscillations of mitochondrial inner membrane potentials. These oscillations are facilitated by both structural coupling through changes in the local redox balance and signaling microdomains and functional coupling that is yet poorly understood. Thus, quantifiable measures of both coupling mechanisms, local dynamic mitochondrial coupling constants and functional clustering coefficients, are likely to offer valuable information on mitochondrial network organization. We provide step-by-step methodologies on how to acquire and assess these measures for inner membrane potential fluorescence fluctuations in laser-scanning two-photon microscope recordings of cardiac myocytes and neurons, that can be applied to other tissues as well.
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MESH Headings
- Animals
- Cluster Analysis
- Fluorescent Dyes/chemistry
- Guinea Pigs
- Image Processing, Computer-Assisted/instrumentation
- Image Processing, Computer-Assisted/methods
- Membrane Potential, Mitochondrial
- Microscopy, Confocal/instrumentation
- Microscopy, Confocal/methods
- Microscopy, Fluorescence/instrumentation
- Microscopy, Fluorescence/methods
- Mitochondria, Heart/metabolism
- Mitochondrial Dynamics
- Models, Biological
- Myocytes, Cardiac/cytology
- Neurons
- Reactive Oxygen Species/metabolism
- Signal Transduction
- Software
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Affiliation(s)
- Felix T Kurz
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
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29
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Johnstone VPA, Viola HM, Hool LC. Dystrophic Cardiomyopathy-Potential Role of Calcium in Pathogenesis, Treatment and Novel Therapies. Genes (Basel) 2017; 8:genes8040108. [PMID: 28338606 PMCID: PMC5406855 DOI: 10.3390/genes8040108] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/16/2017] [Accepted: 03/21/2017] [Indexed: 01/06/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is caused by defects in the DMD gene and results in progressive wasting of skeletal and cardiac muscle due to an absence of functional dystrophin. Cardiomyopathy is prominent in DMD patients, and contributes significantly to mortality. This is particularly true following respiratory interventions that reduce death rate and increase ambulation and consequently cardiac load. Cardiomyopathy shows an increasing prevalence with age and disease progression, and over 95% of patients exhibit dilated cardiomyopathy by the time they reach adulthood. Development of the myopathy is complex, and elevations in intracellular calcium, functional muscle ischemia, and mitochondrial dysfunction characterise the pathophysiology. Current therapies are limited to treating symptoms of the disease and there is therefore an urgent need to treat the underlying genetic defect. Several novel therapies are outlined here, and the unprecedented success of phosphorodiamidate morpholino oligomers (PMOs) in preclinical and clinical studies is overviewed.
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Affiliation(s)
- Victoria P A Johnstone
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
| | - Helena M Viola
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
| | - Livia C Hool
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
- Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia.
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30
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Kurz FT, Aon MA, O'Rourke B, Armoundas AA. Functional Implications of Cardiac Mitochondria Clustering. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:1-24. [PMID: 28551779 PMCID: PMC7003720 DOI: 10.1007/978-3-319-55330-6_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The spatio-temporal organization of mitochondria in cardiac myocytes facilitates myocyte-wide, cluster-bound, mitochondrial inner membrane potential oscillatory depolarizations, commonly triggered by metabolic or oxidative stressors. Local intermitochondrial coupling can be mediated by reactive oxygen species (ROS) that activate inner membrane pores to initiate a ROS-induced-ROS-release process that produces synchronized limit cycle oscillations of mitochondrial clusters within the whole mitochondrial network. The network's dynamic organization, structure and function can be assessed by quantifying dynamic local coupling constants and dynamic functional clustering coefficients, both providing information about the network's response to external stimuli. In addition to its special organization, the mitochondrial network of cardiac myocytes exhibits substrate-sensitive coupling constants and clustering coefficients. The myocyte's ability to form functional clusters of synchronously oscillating mitochondria is sensitive to conditions such as substrate availability (e.g., glucose, pyruvate, β-hydroxybutyrate), antioxidant status, respiratory chain activity, or history of oxidative challenge (e.g., ischemia-reperfusion). This underscores the relevance of quantitative methods to characterize the network's functional status as a way to assess the myocyte's resilience to pathological stressors.
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Affiliation(s)
- Felix T Kurz
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
- Massachusetts General Hospital, Cardiovascular Research Center, Harvard Medical School, Charlestown, MA, USA.
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Antonis A Armoundas
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
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31
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Viola HM, Hool LC. The L-type Ca 2+ channel: A mediator of hypertrophic cardiomyopathy. Channels (Austin) 2016; 11:5-7. [PMID: 27437722 DOI: 10.1080/19336950.2016.1213053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Helena M Viola
- a School of Anatomy, Physiology and Human Biology, The University of Western Australia , Crawley , WA , Australia
| | - Livia C Hool
- a School of Anatomy, Physiology and Human Biology, The University of Western Australia , Crawley , WA , Australia.,b Victor Chang Cardiac Research Institute , Sydney , NSW , Australia
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32
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Sharma A, Nguyen H, Cai L, Lou H. Histone hyperacetylation and exon skipping: a calcium-mediated dynamic regulation in cardiomyocytes. Nucleus 2016; 6:273-8. [PMID: 26325491 DOI: 10.1080/19491034.2015.1081324] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In contrast to cell type-specific pre-mRNA alternative splicing, mechanisms controlling activity-dependent alternative splicing is under-studied and not well understood. In a recent study, we conducted a comprehensive analysis of calcium-mediated mechanism that regulates alternative exon skipping in mouse cardiomyocytes. Our results reveal a strong link between histone hyperacetylation and skipping of cassette exons, and provide support to the kinetic coupling model of the epigenetic regulation of alternative splicing at the chromatin level.
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Affiliation(s)
- Alok Sharma
- a Department of Genetics and Genome Sciences ; Case Western Reserve University ; Cleveland , OH USA
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33
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Viola H, Johnstone V, Cserne Szappanos H, Richman T, Tsoutsman T, Filipovska A, Semsarian C, Hool L. The L-type Ca(2+) channel facilitates abnormal metabolic activity in the cTnI-G203S mouse model of hypertrophic cardiomyopathy. J Physiol 2016; 594:4051-70. [PMID: 27062056 DOI: 10.1113/jp271681] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 04/01/2016] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS Genetic mutations in cardiac troponin I (cTnI) are associated with development of hypertrophic cardiomyopathy characterized by myocyte remodelling, disorganization of cytoskeletal proteins and altered energy metabolism. The L-type Ca(2+) channel is the main route for calcium influx and is crucial to cardiac excitation and contraction. The channel also regulates mitochondrial function in the heart by a functional communication between the channel and mitochondria via the cytoskeletal network. We find that L-type Ca(2+) channel kinetics are altered in cTnI-G203S cardiac myocytes and that activation of the channel causes a significantly greater increase in mitochondrial membrane potential and metabolic activity in cTnI-G203S cardiac myocytes. These responses occur as a result of impaired communication between the L-type Ca(2+) channel and cytoskeletal protein F-actin, involving decreased movement of actin-myosin and block of the mitochondrial voltage-dependent anion channel, resulting in a 'hypermetabolic' mitochondrial state. We propose that L-type Ca(2+) channel antagonists, such as diltiazem, might be effective in reducing the cardiomyopathy by normalizing mitochondrial metabolic activity. ABSTRACT Genetic mutations in cardiac troponin I (cTnI) account for 5% of families with hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy is associated with disorganization of cytoskeletal proteins and altered energy metabolism. The L-type Ca(2+) channel (ICa-L ) plays an important role in regulating mitochondrial function. This involves a functional communication between the channel and mitochondria via the cytoskeletal network. We investigate the role of ICa-L in regulating mitochondrial function in 25- to 30-week-old cardiomyopathic mice expressing the human disease-causing mutation Gly203Ser in cTnI (cTnI-G203S). The inactivation rate of ICa-L is significantly faster in cTnI-G203S myocytes [cTnI-G203S: τ1 = 40.68 ± 3.22, n = 10 vs. wild-type (wt): τ1 = 59.05 ± 6.40, n = 6, P < 0.05]. Activation of ICa-L caused a greater increase in mitochondrial membrane potential (Ψm , 29.19 ± 1.85%, n = 15 vs. wt: 18.84 ± 2.01%, n = 10, P < 0.05) and metabolic activity (24.40 ± 6.46%, n = 8 vs. wt: 9.98 ± 1.57%, n = 9, P < 0.05). The responses occurred because of impaired communication between ICa-L and F-actin, involving lack of dynamic movement of actin-myosin and block of the mitochondrial voltage-dependent anion channel. Similar responses were observed in precardiomyopathic mice. ICa-L antagonists nisoldipine and diltiazem decreased Ψm to basal levels. We conclude that the Gly203Ser mutation leads to impaired functional communication between ICa-L and mitochondria, resulting in a 'hypermetabolic' state. This might contribute to development of cTnI-G203S cardiomyopathy because the response is present in young precardiomyopathic mice. ICa-L antagonists might be effective in reducing the cardiomyopathy by altering mitochondrial function.
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Affiliation(s)
- Helena Viola
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia
| | - Victoria Johnstone
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia
| | - Henrietta Cserne Szappanos
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia
| | - Tara Richman
- The Harry Perkins Institute for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Tatiana Tsoutsman
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, NSW, Australia.,Sydney Medical School, University of Sydney, NSW, Australia
| | - Aleksandra Filipovska
- The Harry Perkins Institute for Medical Research, The University of Western Australia, Crawley, WA, Australia
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, NSW, Australia.,Sydney Medical School, University of Sydney, NSW, Australia.,Department of Cardiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Livia Hool
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia.,Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
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Viola HM, Johnstone VPA, Cserne Szappanos H, Richman TR, Tsoutsman T, Filipovska A, Semsarian C, Seidman JG, Seidman CE, Hool LC. The Role of the L-Type Ca 2+ Channel in Altered Metabolic Activity in a Murine Model of Hypertrophic Cardiomyopathy. JACC Basic Transl Sci 2016; 1:61-72. [PMID: 30167506 PMCID: PMC6113168 DOI: 10.1016/j.jacbts.2015.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 12/31/2015] [Indexed: 01/08/2023]
Abstract
Heterozygous mice (αMHC403/+) expressing the human disease-causing mutation Arg403Gln exhibit cardinal features of hypertrophic cardiomyopathy (HCM) including hypertrophy, myocyte disarray, and increased myocardial fibrosis. Treatment of αMHC403/+mice with the L-type calcium channel (ICa-L) antagonist diltiazem has been shown to decrease left ventricular anterior wall thickness, cardiac myocyte hypertrophy, disarray, and fibrosis. However, the role of the ICa-L in the development of HCM is not known. In addition to maintaining cardiac excitation and contraction in myocytes, the ICa-L also regulates mitochondrial function through transmission of movement of ICa-L via cytoskeletal proteins to mitochondrial voltage-dependent anion channel. Here, the authors investigated the role of ICa-L in regulating mitochondrial function in αMHC403/+mice. Whole-cell patch clamp studies showed that ICa-L current inactivation kinetics were significantly increased in αMHC403/+cardiac myocytes, but that current density and channel expression were similar to wild-type cardiac myocytes. Activation of ICa-L caused a significantly greater increase in mitochondrial membrane potential and metabolic activity in αMHC403/+. These increases were attenuated with ICa-L antagonists and following F-actin or β-tubulin depolymerization. The authors observed increased levels of fibroblast growth factor-21 in αMHC403/+mice, and altered mitochondrial DNA copy number consistent with altered mitochondrial activity and the development of cardiomyopathy. These studies suggest that the Arg403Gln mutation leads to altered functional communication between ICa-L and mitochondria that is associated with increased metabolic activity, which may contribute to the development of cardiomyopathy. ICa-L antagonists may be effective in reducing the cardiomyopathy in HCM by altering metabolic activity. Heterozygous mice (αMHC403/+) expressing the human hypertrophic cardiomyopathy (HCM) disease causing mutation Arg403Gln exhibit cardinal features of HCM. This study investigated the role of L-type Ca2+ channel (ICa-L) in regulating mitochondrial function in Arg403Gln (αMHC403/+) mice. Activation of ICa-L in αMHC403/+mice caused a significantly greater increase in mitochondrial membrane potential and metabolic activity when compared to wild-type mice. Increases in mitochondrial membrane potential and metabolic activity were attenuated with ICa-L antagonists and when F-actin or β-tubulin were depolymerized. ICa-L antagonists may be effective in reducing the cardiomyopathy in HCM by altering metabolic activity.
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Affiliation(s)
- Helena M Viola
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Australia
| | - Victoria P A Johnstone
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Australia
| | - Henrietta Cserne Szappanos
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Australia
| | - Tara R Richman
- The Harry Perkins Institute for Medical Research, The University of Western Australia, Crawley, Australia
| | - Tatiana Tsoutsman
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia.,Sydney Medical School, University of Sydney, Australia
| | - Aleksandra Filipovska
- The Harry Perkins Institute for Medical Research, The University of Western Australia, Crawley, Australia
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Sydney, Australia.,Sydney Medical School, University of Sydney, Australia.,Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
| | | | | | - Livia C Hool
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Australia.,Victor Chang Cardiac Research Institute, Sydney, Australia
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35
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Ochi R, Dhagia V, Lakhkar A, Patel D, Wolin MS, Gupte SA. Rotenone-stimulated superoxide release from mitochondrial complex I acutely augments L-type Ca2+ current in A7r5 aortic smooth muscle cells. Am J Physiol Heart Circ Physiol 2016; 310:H1118-28. [PMID: 26873970 DOI: 10.1152/ajpheart.00889.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/07/2016] [Indexed: 11/22/2022]
Abstract
Voltage-gated L-type Ca(2+) current (ICa,L) induces contraction of arterial smooth muscle cells (ASMCs), and ICa,L is increased by H2O2 in ASMCs. Superoxide released from the mitochondrial respiratory chain (MRC) is dismutated to H2O2 We studied whether superoxide per se acutely modulates ICa,L in ASMCs using cultured A7r5 cells derived from rat aorta. Rotenone is a toxin that inhibits complex I of the MRC and increases mitochondrial superoxide release. The superoxide content of mitochondria was estimated using mitochondrial-specific MitoSOX and HPLC methods, and was shown to be increased by a brief exposure to 10 μM rotenone. ICa,L was recorded with 5 mM BAPTA in the pipette solution. Rotenone administration (10 nM to 10 μM) resulted in a greater ICa,L increase in a dose-dependent manner to a maximum of 22.1% at 10 μM for 1 min, which gradually decreased to 9% after 5 min. The rotenone-induced ICa,L increase was associated with a shift in the current-voltage relationship (I-V) to a hyperpolarizing direction. DTT administration resulted in a 17.9% increase in ICa,L without a negative shift in I-V, and rotenone produced an additional increase with a shift. H2O2 (0.3 mM) inhibited ICa,L by 13%, and additional rotenone induced an increase with a negative shift. Sustained treatment with Tempol (4-hydroxy tempo) led to a significant ICa,L increase but it inhibited the rotenone-induced increase. Staurosporine, a broad-spectrum protein kinase inhibitor, partially inhibited ICa,L and completely suppressed the rotenone-induced increase. Superoxide released from mitochondria affected protein kinases and resulted in stronger ICa,L preceding its dismutation to H2O2 The removal of nitric oxide is a likely mechanism for the increase in ICa,L.
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Affiliation(s)
- Rikuo Ochi
- Department of Pharmacology, New York Medical College, Valhalla, New York; and
| | - Vidhi Dhagia
- Department of Pharmacology, New York Medical College, Valhalla, New York; and
| | - Anand Lakhkar
- Department of Pharmacology, New York Medical College, Valhalla, New York; and
| | - Dhara Patel
- Department of Physiology, New York Medical College, Valhalla, New York
| | - Michael S Wolin
- Department of Physiology, New York Medical College, Valhalla, New York
| | - Sachin A Gupte
- Department of Pharmacology, New York Medical College, Valhalla, New York; and
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Viola HM, Hool LC. Role of the cytoskeleton in communication between L-type Ca(2+) channels and mitochondria. Clin Exp Pharmacol Physiol 2015; 40:295-304. [PMID: 23551128 DOI: 10.1111/1440-1681.12072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 02/25/2013] [Accepted: 02/26/2013] [Indexed: 12/15/2022]
Abstract
The L-type Ca(2+) channel is the main route for Ca(2+) entry into cardiac myocytes, which is essential for the maintenance of cardiac excitation and contraction. Alterations in L-type Ca(2+) channel activity and Ca(2+) homeostasis have been implicated in the development of cardiomyopathies. Cardiac excitation and contraction is fuelled by ATP, synthesized predominantly by the mitochondria via the Ca(2+)-dependent process oxidative phosphorylation. Mitochondrial reactive oxygen species (ROS) are by-products of oxidative phosphorylation and are associated with the development of cardiac pathology. The cytoskeleton plays a role in the communication of signals from the plasma membrane to intracellular organelles. There is good evidence that both L-type Ca(2+) channel activity and mitochondrial function can be modulated by changes in the cytoskeletal network. Activation of the L-type Ca(2+) channel can regulate mitochondrial function through cytoskeletal proteins as a result of transmission of movement from the β(2)-subunit of the channel that occurs during activation and inactivation of the channel. An association between cytoskeletal proteins and the mitochondrial voltage-dependent anion channel (VDAC) may play a role in this response. The L-type Ca(2+) channel is the initiator of contraction in cardiac muscle and the VDAC is responsible for regulating mitochondrial ATP/ADP trafficking. This article presents evidence that a functional coupling between L-type Ca(2+) channels and mitochondria may assist in meeting myocardial energy demand on a beat-to-beat basis.
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Affiliation(s)
- Helena M Viola
- Cardiovascular Electrophysiology Laboratory, School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia
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van Westering TLE, Betts CA, Wood MJA. Current understanding of molecular pathology and treatment of cardiomyopathy in duchenne muscular dystrophy. Molecules 2015; 20:8823-55. [PMID: 25988613 PMCID: PMC6272314 DOI: 10.3390/molecules20058823] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 12/27/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a genetic muscle disorder caused by mutations in the Dmd gene resulting in the loss of the protein dystrophin. Patients do not only experience skeletal muscle degeneration, but also develop severe cardiomyopathy by their second decade, one of the main causes of death. The absence of dystrophin in the heart renders cardiomyocytes more sensitive to stretch-induced damage. Moreover, it pathologically alters intracellular calcium (Ca2+) concentration, neuronal nitric oxide synthase (nNOS) localization and mitochondrial function and leads to inflammation and necrosis, all contributing to the development of cardiomyopathy. Current therapies only treat symptoms and therefore the need for targeting the genetic defect is immense. Several preclinical therapies are undergoing development, including utrophin up-regulation, stop codon read-through therapy, viral gene therapy, cell-based therapy and exon skipping. Some of these therapies are undergoing clinical trials, but these have predominantly focused on skeletal muscle correction. However, improving skeletal muscle function without addressing cardiac aspects of the disease may aggravate cardiomyopathy and therefore it is essential that preclinical and clinical focus include improving heart function. This review consolidates what is known regarding molecular pathology of the DMD heart, specifically focusing on intracellular Ca2+, nNOS and mitochondrial dysregulation. It briefly discusses the current treatment options and then elaborates on the preclinical therapeutic approaches currently under development to restore dystrophin thereby improving pathology, with a focus on the heart.
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Affiliation(s)
- Tirsa L E van Westering
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK
| | - Corinne A Betts
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK.
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK.
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Hardy N, Viola HM, Johnstone VPA, Clemons TD, Cserne Szappanos H, Singh R, Smith NM, Iyer KS, Hool LC. Nanoparticle-mediated dual delivery of an antioxidant and a peptide against the L-Type Ca2+ channel enables simultaneous reduction of cardiac ischemia-reperfusion injury. ACS NANO 2015; 9:279-289. [PMID: 25493575 DOI: 10.1021/nn5061404] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Increased reactive oxygen species (ROS) production and elevated intracellular Ca(2+) following cardiac ischemia-reperfusion injury are key mediators of cell death and the development of cardiac hypertrophy. The L-type Ca(2+) channel is the main route for calcium influx in cardiac myocytes. Activation of the L-type Ca(2+) channel leads to a further increase in mitochondrial ROS production and metabolism. We have previously shown that the application of a peptide derived against the alpha-interacting domain of the L-type Ca(2+) channel (AID) decreases myocardial injury post reperfusion. Herein, we examine the efficacy of simultaneous delivery of the AID peptide in combination with the potent antioxidants curcumin or resveratrol using multifunctional poly(glycidyl methacrylate) (PGMA) nanoparticles. We highlight that drug loading and dissolution are important parameters that have to be taken into account when designing novel combinatorial therapies following cardiac ischemia-reperfusion injury. In the case of resveratrol low loading capacity and fast release rates hinder its applicability as an effective candidate for simultaneous therapy. However, in the case of curcumin, high loading capacity and sustained release rates enable its effective simultaneous delivery in combination with the AID peptide. Simultaneous delivery of the AID peptide with curcumin allowed for effective attenuation of the L-type Ca(2+) channel-activated increases in superoxide (assessed as changes in DHE fluorescence; Empty NP = 53.1 ± 7.6%; NP-C-AID = 7.32 ± 3.57%) and mitochondrial membrane potential (assessed as changes in JC-1 fluorescence; Empty NP = 19.8 ± 2.8%; NP-C-AID=13.05 ± 1.78%). We demonstrate in isolated rat hearts exposed to ischemia followed by reperfusion, that curcumin and the AID peptide in combination effectively reduce muscle damage, decrease oxidative stress and superoxide production in cardiac myocytes.
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Affiliation(s)
- Naviin Hardy
- School of Anatomy, Physiology and Human Biology, The University of Western Australia , Crawley, Western Australia 6009, Australia
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Sharma A, Nguyen H, Geng C, Hinman MN, Luo G, Lou H. Calcium-mediated histone modifications regulate alternative splicing in cardiomyocytes. Proc Natl Acad Sci U S A 2014; 111:E4920-8. [PMID: 25368158 PMCID: PMC4246288 DOI: 10.1073/pnas.1408964111] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In cardiomyocytes, calcium is known to control gene expression at the level of transcription, whereas its role in regulating alternative splicing has not been explored. Here we report that, in mouse primary or embryonic stem cell-derived cardiomyocytes, increased calcium levels induce robust and reversible skipping of several alternative exons from endogenously expressed genes. Interestingly, we demonstrate a calcium-mediated splicing regulatory mechanism that depends on changes of histone modifications. Specifically, the regulation occurs through changes in calcium-responsive kinase activities that lead to alterations in histone modifications and subsequent changes in the transcriptional elongation rate and exon skipping. We demonstrate that increased intracellular calcium levels lead to histone hyperacetylation along the body of the genes containing calcium-responsive alternative exons by disrupting the histone deacetylase-to-histone acetyltransferase balance in the nucleus. Consequently, the RNA polymerase II elongation rate increases significantly on those genes, resulting in skipping of the alternative exons. These studies reveal a mechanism by which calcium-level changes in cardiomyocytes impact on the output of gene expression through altering alternative pre-mRNA splicing patterns.
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Affiliation(s)
| | | | - Cuiyu Geng
- Department of Genetics and Genome Sciences
| | | | - Guangbin Luo
- Department of Genetics and Genome Sciences, Case Comprehensive Cancer Center, and
| | - Hua Lou
- Department of Genetics and Genome Sciences, Case Comprehensive Cancer Center, and Center for RNA Molecular Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106
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Johnstone VPA, Hool LC. Glutathionylation of the L-type Ca2+ channel in oxidative stress-induced pathology of the heart. Int J Mol Sci 2014; 15:19203-25. [PMID: 25340983 PMCID: PMC4227269 DOI: 10.3390/ijms151019203] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 09/29/2014] [Accepted: 10/02/2014] [Indexed: 01/11/2023] Open
Abstract
There is mounting evidence to suggest that protein glutathionylation is a key process contributing to the development of pathology. Glutathionylation occurs as a result of posttranslational modification of a protein and involves the addition of a glutathione moiety at cysteine residues. Such modification can occur on a number of proteins, and exerts a variety of functional consequences. The L-type Ca2+ channel has been identified as a glutathionylation target that participates in the development of cardiac pathology. Ca2+ influx via the L-type Ca2+ channel increases production of mitochondrial reactive oxygen species (ROS) in cardiomyocytes during periods of oxidative stress. This induces a persistent increase in channel open probability, and the resulting constitutive increase in Ca2+ influx amplifies the cross-talk between the mitochondria and the channel. Novel strategies utilising targeted peptide delivery to uncouple mitochondrial ROS and Ca2+ flux via the L-type Ca2+ channel following ischemia-reperfusion have delivered promising results, and have proven capable of restoring appropriate mitochondrial function in myocytes and in vivo.
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Affiliation(s)
- Victoria P A Johnstone
- School of Anatomy, Physiology and Human Biology, the University of Western Australia, Crawley 6009, WA, Australia.
| | - Livia C Hool
- School of Anatomy, Physiology and Human Biology, the University of Western Australia, Crawley 6009, WA, Australia.
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Kurz FT, Aon MA, O'Rourke B, Armoundas AA. Cardiac mitochondria exhibit dynamic functional clustering. Front Physiol 2014; 5:329. [PMID: 25228884 PMCID: PMC4151091 DOI: 10.3389/fphys.2014.00329] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 08/08/2014] [Indexed: 11/21/2022] Open
Abstract
Multi-oscillatory behavior of mitochondrial inner membrane potential ΔΨm in self-organized cardiac mitochondrial networks can be triggered by metabolic or oxidative stress. Spatio-temporal analyses of cardiac mitochondrial networks have shown that mitochondria are heterogeneously organized in synchronously oscillating clusters in which the mean cluster frequency and size are inversely correlated, thus suggesting a modulation of cluster frequency through local inter-mitochondrial coupling. In this study, we propose a method to examine the mitochondrial network's topology through quantification of its dynamic local clustering coefficients. Individual mitochondrial ΔΨm oscillation signals were identified for each cardiac myocyte and cross-correlated with all network mitochondria using previously described methods (Kurz et al., 2010a). Time-varying inter-mitochondrial connectivity, defined for mitochondria in the whole network whose signals are at least 90% correlated at any given time point, allowed considering functional local clustering coefficients. It is shown that mitochondrial clustering in isolated cardiac myocytes changes dynamically and is significantly higher than for random mitochondrial networks that are constructed using the Erdös–Rényi model based on the same sets of vertices. The network's time-averaged clustering coefficient for cardiac myocytes was found to be 0.500 ± 0.051 (N = 9) vs. 0.061 ± 0.020 for random networks, respectively. Our results demonstrate that cardiac mitochondria constitute a network with dynamically connected constituents whose topological organization is prone to clustering. Cluster partitioning in networks of coupled oscillators has been observed in scale-free and chaotic systems and is therefore in good agreement with previous models of cardiac mitochondrial networks.
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Affiliation(s)
- Felix T Kurz
- Department of Neuroradiology, Heidelberg University Hospital Heidelberg, Germany ; Cardiovascular Research Center, Harvard Medical School, Massachusetts General Hospital Charlestown, MA, USA
| | - Miguel A Aon
- Division of Cardiology, Department of Medicine, Johns Hopkins University Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University Baltimore, MD, USA
| | - Antonis A Armoundas
- Cardiovascular Research Center, Harvard Medical School, Massachusetts General Hospital Charlestown, MA, USA
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Impaired functional communication between the L-type calcium channel and mitochondria contributes to metabolic inhibition in the mdx heart. Proc Natl Acad Sci U S A 2014; 111:E2905-14. [PMID: 24969422 DOI: 10.1073/pnas.1402544111] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Duchenne muscular dystrophy is a fatal X-linked disease characterized by the absence of dystrophin. Approximately 20% of boys will die of dilated cardiomyopathy that is associated with cytoskeletal protein disarray, contractile dysfunction, and reduced energy production. However, the mechanisms for altered energy metabolism are not yet fully clarified. Calcium influx through the L-type Ca(2+) channel is critical for maintaining cardiac excitation and contraction. The L-type Ca(2+) channel also regulates mitochondrial function and metabolic activity via transmission of movement of the auxiliary beta subunit through intermediate filament proteins. Here, we find that activation of the L-type Ca(2+) channel is unable to induce increases in mitochondrial membrane potential and metabolic activity in intact cardiac myocytes from the murine model of Duchenne muscular dystrophy (mdx) despite robust increases recorded in wt myocytes. Treatment of mdx mice with morpholino oligomers to induce exon skipping of dystrophin exon 23 (that results in functional dystrophin accumulation) or application of a peptide that resulted in block of voltage-dependent anion channel (VDAC) "rescued" mitochondrial membrane potential and metabolic activity in mdx myocytes. The mitochondrial VDAC coimmunoprecipitated with the L-type Ca(2+) channel. We conclude that the absence of dystrophin in the mdx ventricular myocyte leads to impaired functional communication between the L-type Ca(2+) channel and mitochondrial VDAC. This appears to contribute to metabolic inhibition. These findings provide new mechanistic and functional insight into cardiomyopathy associated with Duchenne muscular dystrophy.
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43
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Viola HM, Jordan MC, Roos KP, Hool LC. Decreased myocardial injury and improved contractility after administration of a peptide derived against the alpha-interacting domain of the L-type calcium channel. J Am Heart Assoc 2014; 3:e000961. [PMID: 24958783 PMCID: PMC4309103 DOI: 10.1161/jaha.114.000961] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background Myocardial infarction remains the leading cause of morbidity and mortality associated with coronary artery disease. The L‐type calcium channel (ICa‐L) is critical to excitation and contraction. Activation of the channel also alters mitochondrial function. Here, we investigated whether application of a alpha‐interacting domain/transactivator of transcription (AID‐TAT) peptide, which immobilizes the auxiliary β2 subunit of the channel and decreases metabolic demand, could alter mitochondrial function and myocardial injury. Methods and Results Treatment with AID‐TAT peptide decreased ischemia‐reperfusion injury in guinea‐pig hearts ex vivo (n=11) and in rats in vivo (n=9) assessed with uptake of nitroblue tetrazolium, release of creatine kinase, and lactate dehydrogenase. Contractility (assessed with catheterization of the left ventricle) was improved after application of AID‐TAT peptide in hearts ex vivo (n=6) and in vivo (n=8) up to 12 weeks before sacrifice. In search of the mechanism for the effect, we found that intracellular calcium ([Ca2+]i, Fura‐2), superoxide production (dihydroethidium fluorescence), mitochondrial membrane potential (Ψm, JC‐1 fluorescence), reduced nicotinamide adenine dinucleotide production, and flavoprotein oxidation (autofluorescence) are decreased after application of AID‐TAT peptide. Conclusions Application of AID‐TAT peptide significantly decreased infarct size and supported contractility up to 12 weeks postcoronary artery occlusion as a result of a decrease in metabolic demand during reperfusion.
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Affiliation(s)
- Helena M Viola
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia (H.M.V., L.C.H.)
| | - Maria C Jordan
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (M.C.J., K.P.R.)
| | - Kenneth P Roos
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA (M.C.J., K.P.R.)
| | - Livia C Hool
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia (H.M.V., L.C.H.)
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How does calcium regulate mitochondrial energetics in the heart? - new insights. Heart Lung Circ 2014; 23:602-9. [PMID: 24657282 DOI: 10.1016/j.hlc.2014.02.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 02/17/2014] [Indexed: 02/07/2023]
Abstract
Maintenance of cellular calcium homeostasis is critical to regulating mitochondrial ATP production and cardiac contraction. The ion channel known as the L-type calcium channel is the main route for calcium entry into cardiac myocytes. The channel associates with cytoskeletal proteins that assist with the communication of signals from the plasma membrane to intracellular organelles, including mitochondria. This article explores the roles of calcium and the cytoskeleton in regulation of mitochondrial function in response to alterations in L-type calcium channel activity. Direct activation of the L-type calcium channel results in an increase in intracellular calcium and increased mitochondrial calcium uptake. As a result, mitochondrial NADH production, oxygen consumption and reactive oxygen species production increase. In addition the L-type calcium channel is able to regulate mitochondrial membrane potential via cytoskeletal proteins when conformational changes in the channel occur during activation and inactivation. Since the L-type calcium channel is the initiator of contraction, a functional coupling between the channel and mitochondria via the cytoskeleton may represent a synchronised process by which mitochondrial function is regulated in addition to calcium influx to meet myocardial energy demand on a beat to beat basis.
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45
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Qian T, Lu S, Ma H, Fang J, Zhong W, Wang Y. FRET imaging of calcium signaling in live cells in the microenvironment. Integr Biol (Camb) 2013; 5:431-8. [PMID: 23250282 DOI: 10.1039/c2ib20264f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The microenvironment has been shown to regulate cellular functions including cell growth, differentiation, proliferation, migration, cancer development and metastasis. However, the underlying molecular mechanism remains largely unclear. We have integrated micro-pattern technology and molecular biosensors based on fluorescence resonance energy transfer (FRET) to visualize calcium responses in cells constrained to grow on a micro-patterned surface. Upon ATP stimulation, human umbilical vein endothelial cells (HUVECs) cultured on different surface micro-patterns had a shorter decay time and a reduced peak of a transient intracellular calcium rise compared to control cells without constraints. The decay time is regulated by the plasma membrane and the membrane calcium channels, while the peak by endoplasmic reticulum (ER) calcium release. Further results revealed that voltage operated channels (VOCs), coupling the plasma membrane and ER, can affect both the decay time and the peak of calcium response. The inhibition of VOCs can eliminate the effect of different micro-patterns on calcium signals. When two connected HUVECs were constrained to grow on a micro-pattern, drastically distinct calcium responses upon ATP stimulation can be observed, in contrast to the similar responses of two connected cells cultured without patterns. Interestingly, the inhibition of VOCs also blocked this difference of calcium responses between two connected cells on micro-patterns. These results indicate that a micro-patterned surface can have a profound effect on the calcium responses of HUVECs under ATP stimulation, largely mediated by VOCs. Therefore, our results shed new light on the molecular mechanism by which HUVECs perceive the microenvironment and regulate intracellular calcium signals.
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Affiliation(s)
- Tongcheng Qian
- Department of Bioengineering & Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, IL 61801, USA
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46
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Clemons TD, Viola HM, House MJ, Iyer KS, Hool LC. Examining efficacy of "TAT-less" delivery of a peptide against the L-type calcium channel in cardiac ischemia-reperfusion injury. ACS NANO 2013; 7:2212-2220. [PMID: 23432114 DOI: 10.1021/nn305211f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Increased calcium influx through the L-type Ca(2+) channel or overexpression of the alpha subunit of the channel induces cardiac hypertrophy. Cardiac hypertrophy results from increased oxidative stress and alterations in cell calcium levels following ischemia-reperfusion injury and is an independent risk factor for increased morbidity and mortality. We find that decreasing the movement of the auxiliary beta subunit with a peptide derived against the alpha-interacting domain (AID) of the channel attenuates ischemia-reperfusion injury. We compared the efficacy of delivering the AID peptide using a trans-activator of transcription (TAT) sequence with that of the peptide complexed to multifunctional polymeric nanoparticles. The AID-tethered nanoparticles perfused through the myocardium more diffusely and associated with cardiac myocytes more rapidly than the TAT-labeled peptide but had similar effects on intracellular calcium levels. The AID-complexed nanoparticles resulted in a similar reduction in release of creatine kinase and lactate dehydrogenase after ischemia-reperfusion to the TAT-labeled peptide. Since nanoparticle delivery also holds the potential for dual drug delivery, we conclude that AID-complexed nanoparticles may provide an effective platform for peptide delivery in cardiac ischemia-reperfusion injuries.
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Affiliation(s)
- Tristan D Clemons
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA 6009, Australia
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47
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Viola HM, Davies SMK, Filipovska A, Hool LC. L-type Ca(2+) channel contributes to alterations in mitochondrial calcium handling in the mdx ventricular myocyte. Am J Physiol Heart Circ Physiol 2013; 304:H767-75. [PMID: 23335798 DOI: 10.1152/ajpheart.00700.2012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The L-type Ca(2+) channel is the main route for calcium entry into cardiac myocytes, and it is essential for contraction. Alterations in whole cell L-type Ca(2+) channel current and Ca(2+) homeostasis have been implicated in the development of cardiomyopathies. Cytoskeletal proteins can influence whole cell L-type Ca(2+) current and mitochondrial function. Duchenne muscular dystrophy is a fatal X-linked disease that leads to progressive muscle weakness due to the absence of cytoskeletal protein dystrophin. This includes dilated cardiomyopathy, but the mechanisms are not well understood. We sought to identify the effect of alterations in whole cell L-type Ca(2+) channel current on mitochondrial function in the murine model of Duchenne muscular dystrophy (mdx). Activation of the L-type Ca(2+) channel with the dihydropyridine agonist BayK(-) caused a significantly larger increase in cytosolic Ca(2+) in mdx vs. wild-type (wt) ventricular myocytes. Consistent with elevated cytosolic Ca(2+), resting mitochondrial Ca(2+), NADH, and mitochondrial superoxide were significantly greater in mdx vs. wt myocytes. Activation of the channel with BayK(-) caused a further increase in mitochondrial Ca(2+), NADH, and superoxide in mdx myocytes. The ratios of the increases were similar to the ratios recorded in wt myocytes. In mitochondria isolated from 8-wk-old mdx hearts, respiration and mitochondrial electron transport chain complex activity were similar to mitochondria isolated from wt hearts. We conclude that mitochondria function at a higher level of resting calcium in the intact mdx myocyte and activation of the L-type Ca(2+) channel contributes to alterations in calcium handling by the mitochondria. This perturbation may contribute to the development of cardiomyopathy.
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Affiliation(s)
- Helena M Viola
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia, Australia
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48
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Different subcellular populations of L-type Ca2+ channels exhibit unique regulation and functional roles in cardiomyocytes. J Mol Cell Cardiol 2011; 52:376-87. [PMID: 21888911 DOI: 10.1016/j.yjmcc.2011.08.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 07/11/2011] [Accepted: 08/17/2011] [Indexed: 11/23/2022]
Abstract
Influx of Ca(2+) through L-type Ca(2+) channels (LTCCs) contributes to numerous cellular processes in cardiomyocytes including excitation-contraction (EC) coupling, membrane excitability, and transcriptional regulation. Distinct subpopulations of LTCCs have been identified in cardiac myocytes, including those at dyadic junctions and within different plasma membrane microdomains such as lipid rafts and caveolae. These subpopulations of LTCCs exhibit regionally distinct functional properties and regulation, affording precise spatiotemporal modulation of L-type Ca(2+) current (I(Ca,L)). Different subcellular LTCC populations demonstrate variable rates of Ca(2+)-dependent inactivation and sometimes coupled gating of neighboring channels, which can lead to focal, persistent I(Ca,L). In addition, the assembly of spatially defined macromolecular signaling complexes permits compartmentalized regulation of I(Ca,L) by a variety of neurohormonal pathways. For example, β-adrenergic receptor subtypes signal to different LTCC subpopulations, with β(2)-adrenergic activation leading to enhanced I(Ca,L) through caveolar LTCCs and β(1)-adrenergic stimulation modulating LTCCs outside of caveolae. Disruptions in the normal subcellular targeting of LTCCs and associated signaling proteins may contribute to the pathophysiology of a variety of cardiac diseases including heart failure and certain arrhythmias. Further identifying the characteristic functional properties and array of regulatory molecules associated with specific LTCC subpopulations will provide a mechanistic framework to understand how LTCCs contribute to diverse cellular processes in normal and diseased myocardium. This article is part of a Special Issue entitled "Local Signaling in Myocytes".
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Adeli S, Zarrindast MR, Niknahad H, Sarkar S, Bidgoli SA, Korani M, Ghasemzadeh P, Rezayat SM. Protective effects of a magnesium magnetic isotope (Mg25)-exchanging nanoparticle (25MgPMC16 ) on mitochondrial functional disorders in esmolol-induced cardiac arrest in rats. ACTA ACUST UNITED AC 2011; 32:1-7. [PMID: 21843205 DOI: 10.1111/j.1474-8673.2011.00464.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In cardiac surgery, agents are needed to produce temporary cardiac arrest (cardioplegia). One of these agents is esmolol (ESM) which is a short-acting selective beta-1 adrenergic receptor antagonist and its overdose causes diastolic ventricular arrest. The (25) MgPMC(16) (porphyrin adducts of cyclohexil fullerene-C60) is known as a nanoparticle which has a cardioprotective effect when the heart is subjected to stressful conditions. In this study, we aimed to confirm the deleterious effects of ESM overdose on cardiac mitochondria and identify any protective effects of (25) MgPMC(16) in male Wistar rats. Esmolol 100 mg kg(-1) (LD50 = 71 mg kg(-1) ) was injected intravenously (i.v.) into tail vein to induce cardiac arrest. This dose was obtained from an ESM dose-response curve which induces at least 80% arrest in rats. (25) MgPMC(16) at three different doses (45, 90 and 224 mg kg(-1) ) was injected i.v. as pretreatment, eight hours before ESM injection. (25) MgCl(2) or (24) MgPMC(16) were used as controls. Following cardiac arrest, the heart was removed and the mitochondria extracted. Mitochondrial viability and the adenosine 5'-diphosphate sodium salt hydrate/Adenosine 5'-triphosphate disodium salt hydrate (ADP/ATP) ratio were measured as biomarkers of mitochondrial function. Results indicate that (25) MgPMC(16) caused a significant increase in mitochondrial viability and decrease in ADP/ATP ratio. No significant changes were seen with (24) MgPMC(16) or (25) MgCl(2) . It is concluded that cardiac arrest induced by ESM overdose leads to a significant decrease in mitochondrial viability and their ATP levels, whereas pretreatment by (25) MgPMC(16) can protect mitochondria by increasing ATP level through liberation of Mg into cells and the improvement of hypoxia.
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Affiliation(s)
- S Adeli
- Department of Pharmacology, Shiraz University of Medical Sciences, Tehran, Iran
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Gravina FS, Jobling P, Kerr KP, de Oliveira RB, Parkington HC, van Helden DF. Oxytocin depolarizes mitochondria in isolated myometrial cells. Exp Physiol 2011; 96:949-56. [DOI: 10.1113/expphysiol.2011.058388] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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