1
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Okabe Y, Murakoshi N, Kurebayashi N, Inoue H, Ito Y, Murayama T, Miyoshi C, Funato H, Ishii K, Xu D, Tajiri K, Qin R, Aonuma K, Murakata Y, Song Z, Wakana S, Yokoyama U, Sakurai T, Aonuma K, Ieda M, Yanagisawa M. An inherited life-threatening arrhythmia model established by screening randomly mutagenized mice. Proc Natl Acad Sci U S A 2024; 121:e2218204121. [PMID: 38621141 PMCID: PMC11047072 DOI: 10.1073/pnas.2218204121] [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: 10/27/2022] [Accepted: 02/27/2024] [Indexed: 04/17/2024] Open
Abstract
Inherited arrhythmia syndromes (IASs) can cause life-threatening arrhythmias and are responsible for a significant proportion of sudden cardiac deaths (SCDs). Despite progress in the development of devices to prevent SCDs, the precise molecular mechanisms that induce detrimental arrhythmias remain to be fully investigated, and more effective therapies are desirable. In the present study, we screened a large-scale randomly mutagenized mouse library by electrocardiography to establish a disease model of IASs and consequently found one pedigree that exhibited spontaneous ventricular arrhythmias (VAs) followed by SCD within 1 y after birth. Genetic analysis successfully revealed a missense mutation (p.I4093V) of the ryanodine receptor 2 gene to be a cause of the arrhythmia. We found an age-related increase in arrhythmia frequency accompanied by cardiomegaly and decreased ventricular contractility in the Ryr2I4093V/+ mice. Ca2+ signaling analysis and a ryanodine binding assay indicated that the mutant ryanodine receptor 2 had a gain-of-function phenotype and enhanced Ca2+ sensitivity. Using this model, we detected the significant suppression of VA following flecainide or dantrolene treatment. Collectively, we established an inherited life-threatening arrhythmia mouse model from an electrocardiogram-based screen of randomly mutagenized mice. The present IAS model may prove feasible for use in investigating the mechanisms of SCD and assessing therapies.
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Affiliation(s)
- Yuta Okabe
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Nobuyuki Murakoshi
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Nagomi Kurebayashi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo113-8421, Japan
| | - Hana Inoue
- Department of Physiology, Tokyo Medical University, Tokyo160-8402, Japan
| | - Yoko Ito
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo113-8421, Japan
| | - Chika Miyoshi
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Hiromasa Funato
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Koichiro Ishii
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo113-8421, Japan
| | - Dongzhu Xu
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Kazuko Tajiri
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Rujie Qin
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Kazuhiro Aonuma
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Yoshiko Murakata
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Zonghu Song
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Shigeharu Wakana
- Technology and Development Team for Mouse Phenotype Analysis, RIKEN BioResource Center, Tsukuba305-0074, Japan
- Department of Animal Experimentation, Foundation for Biomedical Research and Innovation at Kobe, Kobe650-0047, Japan
| | - Utako Yokoyama
- Department of Physiology, Tokyo Medical University, Tokyo160-8402, Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo113-8421, Japan
| | - Kazutaka Aonuma
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba305-8575, Japan
| | - Masaki Ieda
- Department of Cardiology, Keio University School of Medicine, Tokyo160-8582, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba305-8575, Japan
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2
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Zhang X, Wang BZ, Kim M, Nash TR, Liu B, Rao J, Lock R, Tamargo M, Soni RK, Belov J, Li E, Vunjak-Novakovic G, Fine B. STK25 inhibits PKA signaling by phosphorylating PRKAR1A. Cell Rep 2022; 40:111203. [PMID: 35977512 PMCID: PMC9446420 DOI: 10.1016/j.celrep.2022.111203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/10/2022] [Accepted: 07/21/2022] [Indexed: 11/26/2022] Open
Abstract
In the heart, protein kinase A (PKA) is critical for activating calcium handling and sarcomeric proteins in response to beta-adrenergic stimulation leading to increased myocardial contractility and performance. The catalytic activity of PKA is tightly regulated by regulatory subunits that inhibit the catalytic subunit until released by cAMP binding. Phosphorylation of type II regulatory subunits promotes PKA activation; however, the role of phosphorylation in type I regulatory subunits remain uncertain. Here, we utilize human induced pluripotent stem cell cardiomyocytes (iPSC-CMs) to identify STK25 as a kinase of the type Iα regulatory subunit PRKAR1A. Phosphorylation of PRKAR1A leads to inhibition of PKA kinase activity and increased binding to the catalytic subunit in the presence of cAMP. Stk25 knockout in mice diminishes Prkar1a phosphorylation, increases Pka activity, and augments contractile response to beta-adrenergic stimulation. Together, these data support STK25 as a negative regulator of PKA signaling through phosphorylation of PRKAR1A.
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Affiliation(s)
- Xiaokan Zhang
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Bryan Z Wang
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Michael Kim
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Trevor R Nash
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Bohao Liu
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Jenny Rao
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Roberta Lock
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Manuel Tamargo
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Rajesh Kumar Soni
- Proteomics and Macromolecular Crystallography Shared Resource, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
| | - John Belov
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Eric Li
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Gordana Vunjak-Novakovic
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Barry Fine
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY 10032, USA.
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3
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Nusier M, Shah AK, Dhalla NS. Structure-Function Relationships and Modifications of Cardiac Sarcoplasmic Reticulum Ca2+-Transport. Physiol Res 2022; 70:S443-S470. [DOI: 10.33549/physiolres.934805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Sarcoplasmic reticulum (SR) is a specialized tubular network, which not only maintains the intracellular concentration of Ca2+ at a low level but is also known to release and accumulate Ca2+ for the occurrence of cardiac contraction and relaxation, respectively. This subcellular organelle is composed of several phospholipids and different Ca2+-cycling, Ca2+-binding and regulatory proteins, which work in a coordinated manner to determine its function in cardiomyocytes. Some of the major proteins in the cardiac SR membrane include Ca2+-pump ATPase (SERCA2), Ca2+-release protein (ryanodine receptor), calsequestrin (Ca2+-binding protein) and phospholamban (regulatory protein). The phosphorylation of SR Ca2+-cycling proteins by protein kinase A or Ca2+-calmodulin kinase (directly or indirectly) has been demonstrated to augment SR Ca2+-release and Ca2+-uptake activities and promote cardiac contraction and relaxation functions. The activation of phospholipases and proteases as well as changes in different gene expressions under different pathological conditions have been shown to alter the SR composition and produce Ca2+-handling abnormalities in cardiomyocytes for the development of cardiac dysfunction. The post-translational modifications of SR Ca2+ cycling proteins by processes such as oxidation, nitrosylation, glycosylation, lipidation, acetylation, sumoylation, and O GlcNacylation have also been reported to affect the SR Ca2+ release and uptake activities as well as cardiac contractile activity. The SR function in the heart is also influenced in association with changes in cardiac performance by several hormones including thyroid hormones and adiponectin as well as by exercise-training. On the basis of such observations, it is suggested that both Ca2+-cycling and regulatory proteins in the SR membranes are intimately involved in determining the status of cardiac function and are thus excellent targets for drug development for the treatment of heart disease.
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Affiliation(s)
| | | | - NS Dhalla
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen, Research Centre, 351 Tache Avenue, Winnipeg, MB, R2H 2A6 Canada.
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4
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Abstract
Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.
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Affiliation(s)
- Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States; Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), Neuroscience, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
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5
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Stempien A, Josvai M, de Lange WJ, Hernandez JJ, Notbohm J, Kamp TJ, Valdivia HH, Eckhardt LL, Maginot KR, Ralphe JC, Crone WC. Identifying Features of Cardiac Disease Phenotypes Based on Mechanical Function in a Catecholaminergic Polymorphic Ventricular Tachycardia Model. Front Bioeng Biotechnol 2022; 10:873531. [PMID: 35620470 PMCID: PMC9127198 DOI: 10.3389/fbioe.2022.873531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 04/12/2022] [Indexed: 11/23/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is characterized by an arrhythmogenic mechanism involving disruption of calcium handling. This genetic disease can lead to sudden death in children and young adults during physical or emotional stress. Prior CPVT studies have focused on calcium handling, but mechanical functionality has rarely been investigated in vitro. In this research we combine stem cell-derived cardiomyocytes from a CPVT patient (RyR2-H2464D mutation) and a healthy familial control with an engineered culture platform to evaluate mechanical function of cardiomyocytes. Substrates with Young's modulus ranging from 10 to 50 kPa were used in conjunction with microcontact printing of ECM proteins into defined patterns for subsequent attachment. Digital Image Correlation (DIC) was used to evaluate collections of contracting cells. The amplitude of contractile strain was utilized as a quantitative indicator of functionality and disease severity. We found statistically significant differences: the maximum contractile strain was consistently higher in patient samples compared to control samples on all substrate stiffnesses. Additionally, the patient cell line had a statistically significantly slower intrinsic contraction rate than the control, which agrees with prior literature. Differences in mechanical strain have not been previously reported, and hypercontractility is not a known characteristic of CPVT. However, functional changes can occur as the disease progresses, thus this observation may not represent behavior observed in adolescent and adult patients. These results add to the limited studies of mechanical function of CPVT CMs reported in literature and identify functional differences that should be further explored.
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Affiliation(s)
- A Stempien
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.,Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, United States
| | - M Josvai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.,Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, United States
| | - W J de Lange
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - J J Hernandez
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - J Notbohm
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - T J Kamp
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin-Madison, Madison, WI, United States.,Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, United States.,Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - H H Valdivia
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - L L Eckhardt
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin-Madison, Madison, WI, United States.,Cellular and Molecular Arrhythmia Research Program, Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States
| | - K R Maginot
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - J C Ralphe
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - W C Crone
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.,Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, United States.,Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI, United States
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6
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Savarese M, Välipakka S, Johari M, Hackman P, Udd B. Is Gene-Size an Issue for the Diagnosis of Skeletal Muscle Disorders? J Neuromuscul Dis 2021; 7:203-216. [PMID: 32176652 PMCID: PMC7369045 DOI: 10.3233/jnd-190459] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Human genes have a variable length. Those having a coding sequence of extraordinary length and a high number of exons were almost impossible to sequence using the traditional Sanger-based gene-by-gene approach. High-throughput sequencing has partly overcome the size-related technical issues, enabling a straightforward, rapid and relatively inexpensive analysis of large genes. Several large genes (e.g. TTN, NEB, RYR1, DMD) are recognized as disease-causing in patients with skeletal muscle diseases. However, because of their sheer size, the clinical interpretation of variants in these genes is probably the most challenging aspect of the high-throughput genetic investigation in the field of skeletal muscle diseases. The main aim of this review is to discuss the technical and interpretative issues related to the diagnostic investigation of large genes and to reflect upon the current state of the art and the future advancements in the field.
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Affiliation(s)
- Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Salla Välipakka
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Mridul Johari
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Peter Hackman
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical Genetics, Medicum, University of Helsinki, Helsinki, Finland.,Neuromuscular Research Center, Tampere University and University Hospital, Tampere, Finland.,Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
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7
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Chami M, Checler F. Alterations of the Endoplasmic Reticulum (ER) Calcium Signaling Molecular Components in Alzheimer's Disease. Cells 2020; 9:cells9122577. [PMID: 33271984 PMCID: PMC7760721 DOI: 10.3390/cells9122577] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/18/2020] [Accepted: 11/30/2020] [Indexed: 02/07/2023] Open
Abstract
Sustained imbalance in intracellular calcium (Ca2+) entry and clearance alters cellular integrity, ultimately leading to cellular homeostasis disequilibrium and cell death. Alzheimer’s disease (AD) is the most common cause of dementia. Beside the major pathological features associated with AD-linked toxic amyloid beta (Aβ) and hyperphosphorylated tau (p-tau), several studies suggested the contribution of altered Ca2+ handling in AD development. These studies documented physical or functional interactions of Aβ with several Ca2+ handling proteins located either at the plasma membrane or in intracellular organelles including the endoplasmic reticulum (ER), considered the major intracellular Ca2+ pool. In this review, we describe the cellular components of ER Ca2+ dysregulations likely responsible for AD. These include alterations of the inositol 1,4,5-trisphosphate receptors’ (IP3Rs) and ryanodine receptors’ (RyRs) expression and function, dysfunction of the sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) activity and upregulation of its truncated isoform (S1T), as well as presenilin (PS1, PS2)-mediated ER Ca2+ leak/ER Ca2+ release potentiation. Finally, we highlight the functional consequences of alterations of these ER Ca2+ components in AD pathology and unravel the potential benefit of targeting ER Ca2+ homeostasis as a tool to alleviate AD pathogenesis.
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Affiliation(s)
- Mounia Chami
- Correspondence: ; Tel.: +33-4939-53457; Fax: +33-4939-53408
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8
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Marques F, Thapliyal S, Javer A, Shrestha P, Brown AEX, Glauser DA. Tissue-specific isoforms of the single C. elegans Ryanodine receptor gene unc-68 control specific functions. PLoS Genet 2020; 16:e1009102. [PMID: 33104696 PMCID: PMC7644089 DOI: 10.1371/journal.pgen.1009102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 11/05/2020] [Accepted: 09/08/2020] [Indexed: 11/18/2022] Open
Abstract
Ryanodine receptors (RyR) are essential regulators of cellular calcium homeostasis and signaling. Vertebrate genomes contain multiple RyR gene isoforms, expressed in different tissues and executing different functions. In contrast, invertebrate genomes contain a single RyR-encoding gene and it has long been proposed that different transcripts generated by alternative splicing may diversify their functions. Here, we analyze the expression and function of alternative exons in the C. elegans RyR gene unc-68. We show that specific isoform subsets are created via alternative promoters and via alternative splicing in unc-68 Divergent Region 2 (DR2), which actually corresponds to a region of high sequence variability across vertebrate isoforms. The expression of specific unc-68 alternative exons is enriched in different tissues, such as in body wall muscle, neurons and pharyngeal muscle. In order to infer the function of specific alternative promoters and alternative exons of unc-68, we selectively deleted them by CRISPR/Cas9 genome editing. We evaluated pharyngeal function, as well as locomotor function in swimming and crawling with high-content computer-assisted postural and behavioral analysis. Our data provide a comprehensive map of the pleiotropic impact of isoform-specific mutations and highlight that tissue-specific unc-68 isoforms fulfill distinct functions. As a whole, our work clarifies how the C. elegans single RyR gene unc-68 can fulfill multiple tasks through tissue-specific isoforms, and provide a solid foundation to further develop C. elegans as a model to study RyR channel functions and malfunctions.
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Affiliation(s)
- Filipe Marques
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Saurabh Thapliyal
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Avelino Javer
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Priyanka Shrestha
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - André E. X. Brown
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Imperial College London, London, United Kingdom
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9
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Rutkowsky JM, Knotts TA, Allen PD, Pessah IN, Ramsey JJ. Sex-specific alterations in whole body energetics and voluntary activity in heterozygous R163C malignant hyperthermia-susceptible mice. FASEB J 2020; 34:8721-8733. [PMID: 32367593 PMCID: PMC7383697 DOI: 10.1096/fj.202000403] [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] [Received: 02/26/2020] [Accepted: 04/20/2020] [Indexed: 11/20/2022]
Abstract
Malignant hyperthermia (MH) is characterized by induction of skeletal muscle hyperthermia in response to a dysregulated increase in myoplasmic calcium. Although altered energetics play a central role in MH, MH‐susceptible humans and mouse models are often described as having no phenotype until exposure to a triggering agent. The purpose of this study was to determine the influence of the R163C ryanodine receptor 1 mutation, a common MH mutation in humans, on energy expenditure, and voluntary wheel running in mice. Energy expenditure was measured by indirect respiration calorimetry in wild‐type (WT) and heterozygous R163C (HET) mice over a range of ambient temperatures. Energy expenditure adjusted for body weight or lean mass was increased (P < .05) in male, but not female, HET mice housed at 22°C or when housed at 28°C with a running wheel. In female mice, voluntary wheel running was decreased (P < .05) in the HET vs WT animals when analyzed across ambient temperatures. The thermoneutral zone was also widened in both male and female HET mice. The results of the study show that the R163C mutations alters energetics even at temperatures that do not typically induce MH.
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Affiliation(s)
- Jennifer M Rutkowsky
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Trina A Knotts
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Paul D Allen
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Jon J Ramsey
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
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10
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Fusto A, Moyle LA, Gilbert PM, Pegoraro E. Cored in the act: the use of models to understand core myopathies. Dis Model Mech 2019; 12:dmm041368. [PMID: 31874912 PMCID: PMC6955215 DOI: 10.1242/dmm.041368] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The core myopathies are a group of congenital myopathies with variable clinical expression - ranging from early-onset skeletal-muscle weakness to later-onset disease of variable severity - that are identified by characteristic 'core-like' lesions in myofibers and the presence of hypothonia and slowly or rather non-progressive muscle weakness. The genetic causes are diverse; central core disease is most often caused by mutations in ryanodine receptor 1 (RYR1), whereas multi-minicore disease is linked to pathogenic variants of several genes, including selenoprotein N (SELENON), RYR1 and titin (TTN). Understanding the mechanisms that drive core development and muscle weakness remains challenging due to the diversity of the excitation-contraction coupling (ECC) proteins involved and the differential effects of mutations across proteins. Because of this, the use of representative models expressing a mature ECC apparatus is crucial. Animal models have facilitated the identification of disease progression mechanisms for some mutations and have provided evidence to help explain genotype-phenotype correlations. However, many unanswered questions remain about the common and divergent pathological mechanisms that drive disease progression, and these mechanisms need to be understood in order to identify therapeutic targets. Several new transgenic animals have been described recently, expanding the spectrum of core myopathy models, including mice with patient-specific mutations. Furthermore, recent developments in 3D tissue engineering are expected to enable the study of core myopathy disease progression and the effects of potential therapeutic interventions in the context of human cells. In this Review, we summarize the current landscape of core myopathy models, and assess the hurdles and opportunities of future modeling strategies.
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Affiliation(s)
- Aurora Fusto
- Department of Neuroscience, University of Padua, Padua 35128, Italy
| | - Louise A Moyle
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada
- Institute of Biomaterials and Biochemical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Penney M Gilbert
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada
- Institute of Biomaterials and Biochemical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S3G5, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S1A8, Canada
| | - Elena Pegoraro
- Department of Neuroscience, University of Padua, Padua 35128, Italy
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11
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Jiang J, Tang M, Huang Z, Chen L. Junctophilins emerge as novel therapeutic targets. J Cell Physiol 2019; 234:16933-16943. [DOI: 10.1002/jcp.28405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/25/2019] [Accepted: 01/30/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Jinyong Jiang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Mingzhu Tang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Zhen Huang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drugs Study University of South China Hengyang China
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12
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Degovics D, Hartmann P, Németh IB, Árva-Nagy N, Kaszonyi E, Szél E, Strifler G, Bende B, Krenács L, Kemény L, Erős G. A novel target for the promotion of dermal wound healing: Ryanodine receptors. Toxicol Appl Pharmacol 2019; 366:17-24. [PMID: 30684528 DOI: 10.1016/j.taap.2019.01.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/11/2019] [Accepted: 01/23/2019] [Indexed: 10/27/2022]
Abstract
Ryanodine receptors have an important role in the regulation of intracellular calcium levels in the nervous system and muscle. It has been described that ryanodine receptors influence keratinocyte differentiation and barrier homeostasis. Our goal was to examine the role of ryanodine receptors in the healing of full-thickness dermal wounds by means of in vitro and in vivo methods. The effect of ryanodine receptors on wound healing, microcirculation and inflammation was assessed in an in vivo mouse wound healing model, using skin fold chambers in the dorsal region, and in HaCaT cell scratch wound assay in vitro. SKH-1 mice were subjected to sterile saline (n = 36) or ryanodine receptor agonist 4-chloro-m-cresol (0.5 mM) (n = 42) or ryanodine receptor antagonist dantrolene (100 μM) (n = 42). Application of ryanodine receptor agonist 4-chloro-m-cresol did not influence the studied parameters significantly, whereas ryanodine receptor antagonist dantrolene accelerated the wound closure. Inhibition of the calcium channel also increased the vessel diameters in the wound edges during the process of healing and increased the blood flow in the capillaries at all times of measurement. Furthermore, application of dantrolene decreased xanthine-oxidoreductase activity during the inflammatory phase of wound healing. Inhibition of ryanodine receptor-mediated effects positively influence wound healing. Thus, dantrolene may be of therapeutic potential in the treatment of wounds.
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Affiliation(s)
- Döníz Degovics
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary.
| | - Petra Hartmann
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - István Balázs Németh
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Noémi Árva-Nagy
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Enikő Kaszonyi
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Edit Szél
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Gerda Strifler
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Balázs Bende
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - László Krenács
- Laboratory of Tumour Pathology and Molecular Diagnostics, Szeged, Hungary
| | - Lajos Kemény
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary; MTA-SZTE Dermatological Research Group, Szeged, Hungary
| | - Gábor Erős
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
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13
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Yang L, Katchman A, Kushner J, Kushnir A, Zakharov SI, Chen BX, Shuja Z, Subramanyam P, Liu G, Papa A, Roybal D, Pitt GS, Colecraft HM, Marx SO. Cardiac CaV1.2 channels require β subunits for β-adrenergic-mediated modulation but not trafficking. J Clin Invest 2019; 129:647-658. [PMID: 30422117 DOI: 10.1172/jci123878] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/06/2018] [Indexed: 01/01/2023] Open
Abstract
Ca2+ channel β-subunit interactions with pore-forming α-subunits are long-thought to be obligatory for channel trafficking to the cell surface and for tuning of basal biophysical properties in many tissues. Unexpectedly, we demonstrate that transgenic expression of mutant α1C subunits lacking capacity to bind CaVβ can traffic to the sarcolemma in adult cardiomyocytes in vivo and sustain normal excitation-contraction coupling. However, these β-less Ca2+ channels cannot be stimulated by β-adrenergic pathway agonists, and thus adrenergic augmentation of contractility is markedly impaired in isolated cardiomyocytes and in hearts. Similarly, viral-mediated expression of a β-subunit-sequestering peptide sharply curtailed β-adrenergic stimulation of WT Ca2+ channels, identifying an approach to specifically modulate β-adrenergic regulation of cardiac contractility. Our data demonstrate that β subunits are required for β-adrenergic regulation of CaV1.2 channels and positive inotropy in the heart, but are dispensable for CaV1.2 trafficking to the adult cardiomyocyte cell surface, and for basal function and excitation-contraction coupling.
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Affiliation(s)
- Lin Yang
- Division of Cardiology, Department of Medicine, Columbia University
| | | | - Jared Kushner
- Division of Cardiology, Department of Medicine, Columbia University
| | | | | | - Bi-Xing Chen
- Division of Cardiology, Department of Medicine, Columbia University
| | - Zunaira Shuja
- Department of Physiology and Cellular Biophysics, and
| | | | - Guoxia Liu
- Division of Cardiology, Department of Medicine, Columbia University
| | - Arianne Papa
- Department of Physiology and Cellular Biophysics, and
| | - Daniel Roybal
- Department of Pharmacology, Vagelos College of Physicians and Surgeons, New York, New York, USA
| | - Geoffrey S Pitt
- Cardiovascular Research Institute, Weill Cornell Medical College, New York, New York, USA
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, and.,Department of Pharmacology, Vagelos College of Physicians and Surgeons, New York, New York, USA
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, Columbia University.,Department of Pharmacology, Vagelos College of Physicians and Surgeons, New York, New York, USA
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14
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Abstract
Ryanodine receptor type 1-related myopathies (RYR1-RM) are the most common class of congenital myopathies. Historically, RYR1-RM classification and diagnosis have been guided by histopathologic findings on muscle biopsy. Main histological subtypes of RYR1-RM include central core disease, multiminicore disease, core-rod myopathy, centronuclear myopathy, and congenital fiber-type disproportion. A range of RYR1-RM clinical phenotypes has also emerged more recently and includes King Denborough syndrome, RYR1 rhabdomyolysis-myalgia syndrome, atypical periodic paralysis, congenital neuromuscular disease with uniform type 1 fibers, and late-onset axial myopathy. This expansion of the RYR1-RM disease spectrum is due, in part, to implementation of next-generation sequencing methods, which include the entire RYR1 coding sequence rather than being restricted to hotspot regions. These methods enhance diagnostic capabilities, especially given historic limitations of histopathologic and clinical overlap across RYR1-RM. Both dominant and recessive modes of inheritance have been documented, with the latter typically associated with a more severe clinical phenotype. As with all congenital myopathies, no FDA-approved treatments exist to date. Here, we review histopathologic, clinical, imaging, and genetic diagnostic features of the main RYR1-RM subtypes. We also discuss the current state of treatments and focus on disease-modulating (nongenetic) therapeutic strategies under development for RYR1-RM. Finally, perspectives for future approaches to treatment development are broached.
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Affiliation(s)
- Tokunbor A Lawal
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Joshua J Todd
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Katherine G Meilleur
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA.
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15
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Kushnir A, Wajsberg B, Marks AR. Ryanodine receptor dysfunction in human disorders. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1687-1697. [PMID: 30040966 DOI: 10.1016/j.bbamcr.2018.07.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/13/2018] [Accepted: 07/14/2018] [Indexed: 01/07/2023]
Abstract
Regulation of intracellular calcium (Ca2+) is critical in all cell types. The ryanodine receptor (RyR), an intracellular Ca2+ release channel located on the sarco/endoplasmic reticulum (SR/ER), releases Ca2+ from intracellular stores to activate critical functions including muscle contraction and neurotransmitter release. Dysfunctional RyR-mediated Ca2+ handling has been implicated in the pathogenesis of inherited and non-inherited conditions including heart failure, cardiac arrhythmias, skeletal myopathies, diabetes, and neurodegenerative diseases. Here we have reviewed the evidence linking human disorders to RyR dysfunction and describe novel approaches to RyR-targeted therapeutics.
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Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Department of Medicine, Division of Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Benjamin Wajsberg
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA.
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16
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Intracellular Calcium Mobilization Is Required for Sonic Hedgehog Signaling. Dev Cell 2018; 45:512-525.e5. [PMID: 29754802 DOI: 10.1016/j.devcel.2018.04.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 02/28/2018] [Accepted: 04/11/2018] [Indexed: 01/09/2023]
Abstract
Graded Shh signaling across fields of precursor cells coordinates patterns of gene expression, differentiation, and morphogenetic behavior as precursors form complex structures, such as the nervous system, the limbs, and craniofacial skeleton. Here we discover that intracellular calcium mobilization, a process tightly controlled and readily modulated, regulates the level of Shh-dependent gene expression in responding cells and affects the development of all Shh-dependent cell types in the zebrafish embryo. Reduced expression or modified activity of ryanodine receptor (RyR) intracellular calcium release channels shifted the allocation of Shh-dependent cell fates in the somitic muscle and neural tube. Mosaic analysis revealed that RyR-mediated calcium mobilization is required specifically in Shh ligand-receiving cells. This work reveals that RyR channels participate in intercellular signal transduction events. As modulation of RyR activity modifies tissue patterning, we hypothesize that alterations in intracellular calcium mobilization contribute to both birth defects and evolutionary modifications of morphology.
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17
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Singh RM, Waqar T, Howarth FC, Adeghate E, Bidasee K, Singh J. Hyperglycemia-induced cardiac contractile dysfunction in the diabetic heart. Heart Fail Rev 2017; 23:37-54. [DOI: 10.1007/s10741-017-9663-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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18
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Glucagon-like Peptide-1 (GLP-1) and neurotransmitters signaling in epilepsy: An insight review. Neuropharmacology 2017; 136:271-279. [PMID: 29129776 DOI: 10.1016/j.neuropharm.2017.11.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 12/16/2022]
Abstract
Epilepsy is one of the most prevalent neurological disorder affecting more than 50 million people worldwide. Numerous studies have suggested that an imbalance in glutamatergic (excitatory) and GABAergic (inhibitory) neurotransmitter system is one of the dominating pathophysiological mechanisms underlying the occurrence and progression of seizures. Further, this alteration in GABAergic and glutamatergic system disrupts the delicate balance of other neurotransmitters system in the brain. Emerging strides have documented the protective role of GLP-1 signaling on altered neurotransmitters signaling in Epilepsy and associated co-morbidities. GLP-1 is neuropeptide and synthesized by preproglucagon (PPG) neurons in the brain. GLP-1 receptors are widely distributed throughout the brain including hippocampus (CA3 and CA1 region) and implicated in various neurological disorders like Epilepsy. A complete understanding of alteration in neurotransmitters signaling will provide essential insight into the basic pathogenic mechanisms of epilepsy and may uncover novel targets for future drug therapies. Presently, treatment of epilepsy is palliative in nature, providing only symptomatic relief to patients. The apparent or traditional approach of treating epileptic subjects with anti-epileptic drugs is associated with variety of adverse effects. Therefore, alternative approaches that can restore altered neurotransmitter signaling are being tried and adopted. Present review is an attempt to highlight the emerging protective role of GLP-1 signaling on altered neurotransmitters signaling in epilepsy. Authors have made significant efforts to discuss effect of various GLP-1 analogs on various neurotransmitters system and associated molecular and cellular pathways as a potential drug target for the management of epilepsy and associated co-morbidities. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'
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19
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Ryanodine receptors contribute to the induction of ischemic tolerance. Brain Res Bull 2016; 122:45-53. [DOI: 10.1016/j.brainresbull.2016.02.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 12/14/2015] [Accepted: 02/24/2016] [Indexed: 11/21/2022]
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20
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Segal M, Korkotian E. Roles of Calcium Stores and Store-Operated Channels in Plasticity of Dendritic Spines. Neuroscientist 2015; 22:477-85. [PMID: 26511041 DOI: 10.1177/1073858415613277] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Calcium stores in the endoplasmic reticulum play important roles in a variety of mammalian cellular functions. However, the multitude of calcium-handling machineries in neurons, including voltage- and ligand-gated channels, calcium-binding proteins, pumps, and transporters, as well as the rapid mobility of calcium ions among different cellular compartments hampered the singling out of calcium stores as a pivotal player in synaptic plasticity. Despite these methodological obstacles, novel molecular and imaging tools afforded a rapid progress in deciphering the role of specific calcium stores in neuronal functions. In the present review, we will address several key issues related to the involvement of ryanodine receptors and the calcium entry channel Orai1 in dendritic spine development and plasticity as well as their derailing in neurodegenerative diseases.
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Affiliation(s)
- Menahem Segal
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel
| | - Eduard Korkotian
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel
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21
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Walweel K, Laver DR. Mechanisms of SR calcium release in healthy and failing human hearts. Biophys Rev 2015; 7:33-41. [PMID: 28509976 PMCID: PMC5425750 DOI: 10.1007/s12551-014-0152-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 11/25/2014] [Indexed: 01/08/2023] Open
Abstract
Normal heart contraction and rhythm relies on the proper flow of calcium ions (Ca2+) into cardiac cells and between their intracellular organelles, and any disruption can lead to arrhythmia and sudden cardiac death. Electrical excitation of the surface membrane activates voltage-dependent L-type Ca2+ channels to open and allow Ca2+ to enter the cytoplasm. The subsequent increase in cytoplasmic Ca2+ concentration activates calcium release channels (RyR2) located at specialised Ca2+ release sites in the sarcoplasmic reticulum (SR), which serves as an intracellular Ca2+ store. Animal models have provided valuable insights into how intracellular Ca2+ transport mechanisms are altered in human heart failure. The aim of this review is to examine how Ca2+ release sites are remodelled in heart failure and how this affects intracellular Ca2+ transport with an emphasis on Ca2+ release mechanisms in the SR. Current knowledge on how heart failure alters the regulation of RyR2 by Ca2+ and Mg2+ and how these mechanisms control the activity of RyR2 in the confines of the Ca2+ release sites is reviewed.
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Affiliation(s)
- K Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| | - D R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia.
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22
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Abstract
The triad is a skeletal muscle substructure responsible for the regulation of excitation-contraction coupling. It is formed by the close apposition of the T-tubule and the terminal sarcoplasmic reticulum. A rapidly growing list of skeletal myopathies, here referred to as triadopathies, are caused by gene mutations in components of the triad. These disorders, at their root, are caused by defects in excitation contraction coupling and intracellular calcium homeostasis. Secondary abnormalities in triad structure and/or function are also reported in several muscle diseases, most notably certain muscular dystrophies. This review highlights the current understanding of both primary and secondary triadopathies, and identifies important concepts yet to be fully addressed in the field. The emphasis of the review is both on the pathogenesis of triadopathies and their potential treatment.
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Affiliation(s)
- James J Dowling
- Division of Neurology and Genetics and Genome Biology Program, Hospital for Sick Children, Toronto, ON, Canada,
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23
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Dobrev D, Wehrens XHT. Role of RyR2 phosphorylation in heart failure and arrhythmias: Controversies around ryanodine receptor phosphorylation in cardiac disease. Circ Res 2014; 114:1311-9; discussion 1319. [PMID: 24723656 DOI: 10.1161/circresaha.114.300568] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cardiac ryanodine receptor type 2 plays a key role in excitation-contraction coupling. The ryanodine receptor type 2 channel protein is modulated by various post-translational modifications, including phosphorylation by protein kinase A and Ca(2+)/calmodulin protein kinase II. Despite extensive research in this area, the functional effects of ryanodine receptor type 2 phosphorylation remain disputed. In particular, the potential involvement of increased ryanodine receptor type 2 phosphorylation in the pathogenesis of heart failure and arrhythmias remains a controversial area, which is discussed in this review article.
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Affiliation(s)
- Dobromir Dobrev
- From the Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany (D.D.); and Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, and Medicine-Cardiology, Baylor College of Medicine, Houston, TX (X.H.T.W.)
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24
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Cassar M, Issa AR, Riemensperger T, Petitgas C, Rival T, Coulom H, Iché-Torres M, Han KA, Birman S. A dopamine receptor contributes to paraquat-induced neurotoxicity in Drosophila. Hum Mol Genet 2014; 24:197-212. [PMID: 25158689 DOI: 10.1093/hmg/ddu430] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Long-term exposure to environmental oxidative stressors, like the herbicide paraquat (PQ), has been linked to the development of Parkinson's disease (PD), the most frequent neurodegenerative movement disorder. Paraquat is thus frequently used in the fruit fly Drosophila melanogaster and other animal models to study PD and the degeneration of dopaminergic neurons (DNs) that characterizes this disease. Here, we show that a D1-like dopamine (DA) receptor, DAMB, actively contributes to the fast central nervous system (CNS) failure induced by PQ in the fly. First, we found that a long-term increase in neuronal DA synthesis reduced DAMB expression and protected against PQ neurotoxicity. Secondly, a striking age-related decrease in PQ resistance in young adult flies correlated with an augmentation of DAMB expression. This aging-associated increase in oxidative stress vulnerability was not observed in a DAMB-deficient mutant. Thirdly, targeted inactivation of this receptor in glutamatergic neurons (GNs) markedly enhanced the survival of Drosophila exposed to either PQ or neurotoxic levels of DA, whereas, conversely, DAMB overexpression in these cells made the flies more vulnerable to both compounds. Fourthly, a mutation in the Drosophila ryanodine receptor (RyR), which inhibits activity-induced increase in cytosolic Ca(2+), also strongly enhanced PQ resistance. Finally, we found that DAMB overexpression in specific neuronal populations arrested development of the fly and that in vivo stimulation of either DNs or GNs increased PQ susceptibility. This suggests a model for DA receptor-mediated potentiation of PQ-induced neurotoxicity. Further studies of DAMB signaling in Drosophila could have implications for better understanding DA-related neurodegenerative disorders in humans.
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Affiliation(s)
- Marlène Cassar
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France
| | - Abdul-Raouf Issa
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France
| | - Thomas Riemensperger
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France
| | - Céline Petitgas
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France
| | - Thomas Rival
- Genetics and Physiopathology of Neurotransmission, Developmental Biology Institute of Marseille-Luminy, CNRS, Université de la Méditerranée, 13009 Marseille, France and
| | - Hélène Coulom
- Genetics and Physiopathology of Neurotransmission, Developmental Biology Institute of Marseille-Luminy, CNRS, Université de la Méditerranée, 13009 Marseille, France and
| | - Magali Iché-Torres
- Genetics and Physiopathology of Neurotransmission, Developmental Biology Institute of Marseille-Luminy, CNRS, Université de la Méditerranée, 13009 Marseille, France and
| | - Kyung-An Han
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
| | - Serge Birman
- Genes Circuits Rhythms and Neuropathologies, Brain Plasticity Unit, CNRS, PSL Research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France Genetics and Physiopathology of Neurotransmission, Developmental Biology Institute of Marseille-Luminy, CNRS, Université de la Méditerranée, 13009 Marseille, France and
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25
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Baumann CW, Rogers RG, Gahlot N, Ingalls CP. Eccentric contractions disrupt FKBP12 content in mouse skeletal muscle. Physiol Rep 2014; 2:2/7/e12081. [PMID: 25347864 PMCID: PMC4187567 DOI: 10.14814/phy2.12081] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Strength deficits associated with eccentric contraction‐induced muscle injury stem, in part, from impaired voltage‐gated sarcoplasmic reticulum (SR) Ca2+ release. FKBP12 is a 12‐kD immunophilin known to bind to the SR Ca2+ release channel (ryanodine receptor, RyR1) and plays an important role in excitation‐contraction coupling. To assess the effects of eccentric contractions on FKBP12 content, we measured anterior crural muscle (tibialis anterior [TA], extensor digitorum longus [EDL], extensor hallucis longus muscles) strength and FKBP12 content in pellet and supernatant fractions after centrifugation via immunoblotting from mice before and after a single bout of either 150 eccentric or concentric contractions. There were no changes in peak isometric torque or FKBP12 content in TA muscles after concentric contractions. However, FKBP12 content was reduced in the pelleted fraction immediately after eccentric contractions, and increased in the soluble protein fraction 3 day after injury induction. FKBP12 content was correlated (P = 0.025; R2= 0.38) to strength deficits immediately after injury induction. In summary, eccentric contraction‐induced muscle injury is associated with significant alterations in FKBP12 content after injury, and is correlated with changes in peak isometric torque. Eccentric contraction‐induced muscle injury is associated with immediate and prolonged strength deficits that stem in part from impaired sarcoplasmic reticulum (SR) calcium release. The content of FKBP12, a 12‐kD immunophilin known to bind to the SR calcium release channel and influence SR calcium release, is reduced in mouse skeletal muscle immediately after injury induction and is significantly associated with strength deficits.
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Affiliation(s)
- Cory W Baumann
- Department of Kinesiology and Health, Muscle Biology Laboratory, Georgia State University, Atlanta, 30302, Georgia
| | - Russell G Rogers
- Department of Kinesiology and Health, Muscle Biology Laboratory, Georgia State University, Atlanta, 30302, Georgia
| | - Nidhi Gahlot
- Department of Kinesiology and Health, Muscle Biology Laboratory, Georgia State University, Atlanta, 30302, Georgia
| | - Christopher P Ingalls
- Department of Kinesiology and Health, Muscle Biology Laboratory, Georgia State University, Atlanta, 30302, Georgia
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26
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Segal M, Korkotian E. Endoplasmic reticulum calcium stores in dendritic spines. Front Neuroanat 2014; 8:64. [PMID: 25071469 PMCID: PMC4089118 DOI: 10.3389/fnana.2014.00064] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 06/23/2014] [Indexed: 12/14/2022] Open
Abstract
Despite decades of research, the role of calcium stores in dendritic spines structure, function and plasticity is still debated. The reasons for this may have to do with the multitude of overlapping calcium handling machineries in the neuron, including stores, voltage and ligand gated channels, pumps and transporters. Also, different cells in the brain are endowed with calcium stores that are activated by different receptor types, and their differential compartmentalization in dendrites, spines and presynaptic terminals complicates their analysis. In the present review we address several key issues, including the role of calcium stores in synaptic plasticity, their role during development, in stress and in neurodegenerative diseases. Apparently, there is increasing evidence for a crucial role of calcium stores, especially of the ryanodine species, in synaptic plasticity and neuronal survival.
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Affiliation(s)
- Menahem Segal
- Department of Neurobiology, The Weizman Institute Rehovot, Israel
| | - Eduard Korkotian
- Department of Neurobiology, The Weizman Institute Rehovot, Israel
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27
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Landstrom AP, Beavers DL, Wehrens XHT. The junctophilin family of proteins: from bench to bedside. Trends Mol Med 2014; 20:353-62. [PMID: 24636942 PMCID: PMC4041816 DOI: 10.1016/j.molmed.2014.02.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 02/10/2014] [Accepted: 02/14/2014] [Indexed: 12/25/2022]
Abstract
Excitable tissues rely on junctional membrane complexes to couple cell surface signals to intracellular channels. The junctophilins have emerged as a family of proteins critical in coordinating the maturation and maintenance of this cellular ultrastructure. Within skeletal and cardiac muscle, junctophilin 1 and junctophilin 2, respectively, couple sarcolemmal and intracellular calcium channels. In neuronal tissue, junctophilin 3 and junctophilin 4 may have an emerging role in coupling membrane neurotransmitter receptors and intracellular calcium channels. These important physiological roles are highlighted by the pathophysiology which results when these proteins are perturbed, and a growing body of literature has associated junctophilins with the pathogenesis of human disease.
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Affiliation(s)
- Andrew P Landstrom
- Department of Pediatrics, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - David L Beavers
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xander H T Wehrens
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Medicine (Cardiology), Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA.
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Niknam Y, Feng W, Cherednichenko G, Dong Y, Joshi SN, Vyas SM, Lehmler HJ, Pessah IN. Structure-activity relationship of selected meta- and para-hydroxylated non-dioxin like polychlorinated biphenyls: from single RyR1 channels to muscle dysfunction. Toxicol Sci 2013; 136:500-13. [PMID: 24014653 DOI: 10.1093/toxsci/kft202] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Non-dioxin like polychlorinated biphenyls (NDL-PCBs) are legacy environmental contaminants with contemporary unintentional sources. NDL-PCBs interact with ryanodine receptors (RyRs), Ca(2+) channels of sarcoplasmic/endoplasmic reticulum (SR/ER) that regulate excitation-contraction coupling (ECC) and Ca(2+)-dependent cell signaling in muscle. Activities of 4 chiral congeners PCB91, 95, 132, and 149 and their respective 4- and 5-hydroxy (-OH) derivatives toward rabbit skeletal muscle ryanodine receptor (RyR1) are investigated using [(3)H]ryanodine binding and SR Ca(2+) flux analyses. Although 5-OH metabolites have comparable activity to their respective parent in both assays, 4-OH derivatives are unable to trigger Ca(2+) release from SR microsomes in the presence of Ca(2+)-ATPase activity. PCB95 and derivatives are investigated using single channel voltage-clamp and primary murine embryonic muscle cells (myotubes). Like PCB95, 5-OH-PCB95 quickly and persistently increases channel open probability (p o > .9) by stabilizing the full-open channel state, whereas 4-OH-PCB95 transiently enhances p o. Ca(2+) imaging of myotubes loaded with Fluo-4 show that acute exposure to PCB95 (5 µM) potentiates ECC and caffeine responses and partially depletes SR Ca(2+) stores. Exposure to 5-OH-PCB95 (5 µM) increases cytoplasmic Ca(2+), leading to rapid ECC failure in 50% of myotubes with the remainder retaining negligible responses. 4-OH-PCB95 neither increases baseline Ca(2+) nor causes ECC failure but depresses ECC and caffeine responses by 50%. With longer (3h) exposure to 300 nM PCB95, 5-OH-PCB95, or 4-OH-PCB95 decreases the number of ECC responsive myotubes by 22%, 81%, and 51% compared with control by depleting SR Ca(2+) and/or uncoupling ECC. NDL-PCBs and their 5-OH and 4-OH metabolites differentially influence RyR1 channel activity and ECC in embryonic skeletal muscle.
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Affiliation(s)
- Yassaman Niknam
- * Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616
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29
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Abstract
BACKGROUND Although in vitro studies have identified numerous possible targets, the molecules that mediate the in vivo effects of volatile anesthetics remain largely unknown. The mammalian ryanodine receptor (Ryr) is a known halothane target, and the authors hypothesized that it has a central role in anesthesia. METHODS Gene function of the Drosophila Ryr (dRyr) was manipulated in the whole body or in specific tissues using a collection of mutants and transgenes, and responses to halothane were measured with a reactive climbing assay. Cellular responses to halothane were studied using Ca imaging and patch clamp electrophysiology. RESULTS Halothane potency strongly correlates with dRyr gene copy number, and missense mutations in regions known to be functionally important in the mammalian Ryrs gene cause dominant hypersensitivity. Tissue-specific manipulation of dRyr shows that expression in neurons and glia, but not muscle, mediates halothane sensitivity. In cultured cells, halothane-induced Ca efflux is strictly dRyr-dependent, suggesting a close interaction between halothane and dRyr. Ca imaging and electrophysiology of Drosophila central neurons reveal halothane-induced Ca flux that is altered in dRyr mutants and correlates with strong hyperpolarization. CONCLUSIONS In Drosophila, neurally expressed dRyr mediates a substantial proportion of the anesthetic effects of halothane in vivo, is potently activated by halothane in vitro, and activates an inhibitory conductance. The authors' results provide support for Ryr as an important mediator of immobilization by volatile anesthetics.
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Marx SO, Marks AR. Dysfunctional ryanodine receptors in the heart: new insights into complex cardiovascular diseases. J Mol Cell Cardiol 2013; 58:225-31. [PMID: 23507255 DOI: 10.1016/j.yjmcc.2013.03.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/26/2013] [Accepted: 03/02/2013] [Indexed: 01/07/2023]
Abstract
Calcium dependent signaling is highly regulated in cardiomyocytes and determines the force of cardiac muscle contraction. The cardiac ryanodine receptors (RyR2) play important roles in health and disease. Modulation of RyR2 by phosphorylation is required for sympathetic regulation of cardiac function. Abnormal regulation of RyR2 contributes to heart failure, and atrial and ventricular arrhythmias. RyR2 channels are oxidized, nitrosylated, and hyperphosphorylated by protein kinase A (PKA) in heart failure, resulting in "leaky" channels. These leaky RyR2 channels contribute to depletion of calcium from the sarcoplasmic reticulum, resulting in defective cardiac excitation-contraction coupling. In this review, we discuss both the importance of PKA and calcium/calmodulin-dependent kinase II (CaMKII) regulation of RyR2 in health, and how altered phosphorylation, nitrosylation and oxidation of RyR2 channels lead to cardiac disease. Correcting these defects using either genetic manipulation (knock-in) in mice, or specific and novel small molecules ameliorates the RyR2 dysfunction, reducing the progression to heart failure and the incidence of arrhythmias.
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Affiliation(s)
- Steven O Marx
- Division of Cardiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
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31
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Marks AR. Calcium cycling proteins and heart failure: mechanisms and therapeutics. J Clin Invest 2013; 123:46-52. [PMID: 23281409 DOI: 10.1172/jci62834] [Citation(s) in RCA: 270] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ca2+-dependent signaling is highly regulated in cardiomyocytes and determines the force of cardiac muscle contraction. Ca2+ cycling refers to the release and reuptake of intracellular Ca2+ that drives muscle contraction and relaxation. In failing hearts, Ca2+ cycling is profoundly altered, resulting in impaired contractility and fatal cardiac arrhythmias. The key defects in Ca2+ cycling occur at the level of the sarcoplasmic reticulum (SR), a Ca2+ storage organelle in muscle. Defects in the regulation of Ca2+ cycling proteins including the ryanodine receptor 2, cardiac (RyR2)/Ca2+ release channel macromolecular complexes and the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a)/phospholamban complex contribute to heart failure. RyR2s are oxidized, nitrosylated, and PKA hyperphosphorylated, resulting in "leaky" channels in failing hearts. These leaky RyR2s contribute to depletion of Ca2+ from the SR, and the leaking Ca2+ depolarizes cardiomyocytes and triggers fatal arrhythmias. SERCA2a is downregulated and phospholamban is hypophosphorylated in failing hearts, resulting in impaired SR Ca2+ reuptake that conspires with leaky RyR2 to deplete SR Ca2+. Two new therapeutic strategies for heart failure (HF) are now being tested in clinical trials: (a) fixing the leak in RyR2 channels with a novel class of Ca2+-release channel stabilizers called Rycals and (b) increasing expression of SERCA2a to improve SR Ca2+ reuptake with viral-mediated gene therapy. There are many potential opportunities for additional mechanism-based therapeutics involving the machinery that regulates Ca2+ cycling in the heart.
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Affiliation(s)
- Andrew R Marks
- Department of Physiology and Cellular Biophysics and The Clyde and Helen Wu Center for Molecular Cardiology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.
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32
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Kushnir A, Marks AR. Ryanodine receptor patents. Recent Pat Biotechnol 2012; 6:157-166. [PMID: 23092431 PMCID: PMC3690504 DOI: 10.2174/1872208311206030157] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 07/30/2012] [Accepted: 08/04/2012] [Indexed: 06/01/2023]
Abstract
Research over the past two decades has implicated dysfunction of the ryanodine receptor (RyR), a Ca(2+) release channel on the sarcoplasmic reticulum (SR) required for excitation-contraction (EC) coupling, in the pathogenesis of cardiac and skeletal myopathies. These discoveries have led to the development of novel drugs, screening tools, and research methods. The patents associated with these advances tell the story of the initial discovery of RyRs as a target for plant alkaloids, to their central role in cardiac and skeletal muscle excitation-contraction coupling, and ongoing clinical trials with a novel class of drugs called RycalsTM that inhibit pathological intracellular Ca(2+) leak. Additionally, these patents highlight questions, controversies, and future directions of the RyR field.
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Affiliation(s)
- Alexander Kushnir
- Department of Medicine, Jacobi Medical Center, Albert Einstein College of Medicine, 1400 Pelham Parkway South, New York, NY 10461
| | - Andrew R. Marks
- Clyde and Helen Wu Center for Molecular Cardiology, Departments of Physiology and Cellular Biophysics, and Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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33
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Novel ryanodine receptor 2 mutation associated with a severe phenotype of catecholaminergic polymorphic ventricular tachycardia. J Pediatr 2012; 161:362-4. [PMID: 22608700 DOI: 10.1016/j.jpeds.2012.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 02/22/2012] [Accepted: 04/12/2012] [Indexed: 11/23/2022]
Abstract
An adolescent girl with a history of anxiety associated seizure-like episodes was ultimately diagnosed with catecholaminergic polymorphic ventricular tachycardia. She tested positive for a novel mutation of the ryanodine receptor. The report underscores how genetic arrhythmia syndromes may be mistaken for neurologic disorders.
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34
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Zissimopoulos S, Seifan S, Maxwell C, Williams AJ, Lai FA. Disparities in the association of the ryanodine receptor and the FK506-binding proteins in mammalian heart. J Cell Sci 2012; 125:1759-69. [PMID: 22328519 DOI: 10.1242/jcs.098012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The FK506-binding proteins (FKBP12 and FKBP12.6; also known as FKBP1A and FKBP1B, respectively) are accessory subunits of the ryanodine receptor (RyR) Ca(2+) release channel. Aberrant RyR2-FKBP12.6 interactions have been proposed to be the underlying cause of channel dysfunction in acquired and inherited cardiac disease. However, the stoichiometry of the RyR2 association with FKBP12 or FKBP12.6 in mammalian heart is currently unknown. Here, we describe detailed quantitative analysis of cardiac stoichiometry between RyR2 and FKBP12 or FKBP12.6 using immunoblotting and [(3)H]ryanodine-binding assays, revealing striking disparities between four mammalian species. In mouse and pig heart, RyR2 is found complexed with both FKBP12 and FKBP12.6, although the former is the most abundant isoform. In rat heart, RyR2 is predominantly associated with FKBP12.6, whereas in rabbit it is associated with FKBP12 only. Co-immunoprecipitation experiments demonstrate RyR2-specific interaction with both FKBP isoforms in native cardiac tissue. Assuming four FKBP-binding sites per RyR2 tetramer, only a small proportion of available sites are occupied by endogenous FKBP12.6. FKBP interactions with RyR2 are very strong and resistant to drug (FK506, rapamycin and cyclic ADPribose) and redox (H(2)O(2) and diamide) treatment. By contrast, the RyR1-FKBP12 association in skeletal muscle is readily disrupted under oxidative conditions. This is the first study to directly assess association of endogenous FKBP12 and FKBP12.6 with RyR2 in native cardiac tissue. Our results challenge the widespread perception that RyR2 associates exclusively with FKBP12.6 to near saturation, with important implications for the role of the FK506-binding proteins in RyR2 pathophysiology and cardiac disease.
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Affiliation(s)
- Spyros Zissimopoulos
- Wales Heart Research Institute, Department of Cardiology, Cardiff University School of Medicine, Cardiff, UK.
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35
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Ryanodine Receptors Are Expressed in Epidermal Keratinocytes and Associated with Keratinocyte Differentiation and Epidermal Permeability Barrier Homeostasis. J Invest Dermatol 2012; 132:69-75. [DOI: 10.1038/jid.2011.256] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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36
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nNOS regulation of skeletal muscle fatigue and exercise performance. Biophys Rev 2011; 3:209-217. [PMID: 28510048 DOI: 10.1007/s12551-011-0060-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 10/17/2011] [Indexed: 10/15/2022] Open
Abstract
Neuronal nitric oxide synthases (nNOS) are Ca2+/calmodulin-activated enzymes that synthesize the gaseous messenger nitric oxide (NO). nNOSμ and the recently described nNOSβ, both spliced nNOS isoforms, are important enzymatic sources of NO in skeletal muscle, a tissue long considered to be a paradigmatic system for studying NO-dependent redox signaling. nNOS is indispensable for skeletal muscle integrity and contractile performance, and deregulation of nNOSμ signaling is a common pathogenic feature of many neuromuscular diseases. Recent evidence suggests that both nNOSμ and nNOSβ regulate skeletal muscle size, strength, and fatigue resistance, making them important players in exercise performance. nNOSμ acts as an activity sensor and appears to assist skeletal muscle adaptation to new functional demands, particularly those of endurance exercise. Prolonged inactivity leads to nNOS-mediated muscle atrophy through a FoxO-dependent pathway. nNOS also plays a role in modulating exercise performance in neuromuscular disease. In the mdx mouse model of Duchenne muscular dystrophy, defective nNOS signaling is thought to restrict contractile capacity of working muscle in two ways: loss of sarcolemmal nNOSμ causes excessive ischemic damage while residual cytosolic nNOSμ contributes to hypernitrosylation of the ryanodine receptor, causing pathogenic Ca2+ leak. This defect in Ca2+ handling promotes muscle damage, weakness, and fatigue. This review addresses these recent advances in the understanding of nNOS-dependent redox regulation of skeletal muscle function and exercise performance under physiological and neuromuscular disease conditions.
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37
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Darszon A, Nishigaki T, Beltran C, Treviño CL. Calcium Channels in the Development, Maturation, and Function of Spermatozoa. Physiol Rev 2011; 91:1305-55. [DOI: 10.1152/physrev.00028.2010] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A proper dialogue between spermatozoa and the egg is essential for conception of a new individual in sexually reproducing animals. Ca2+ is crucial in orchestrating this unique event leading to a new life. No wonder that nature has devised different Ca2+-permeable channels and located them at distinct sites in spermatozoa so that they can help fertilize the egg. New tools to study sperm ionic currents, and image intracellular Ca2+ with better spatial and temporal resolution even in swimming spermatozoa, are revealing how sperm ion channels participate in fertilization. This review critically examines the involvement of Ca2+ channels in multiple signaling processes needed for spermatozoa to mature, travel towards the egg, and fertilize it. Remarkably, these tiny specialized cells can express exclusive channels like CatSper for Ca2+ and SLO3 for K+, which are attractive targets for contraception and for the discovery of novel signaling complexes. Learning more about fertilization is a matter of capital importance; societies face growing pressure to counteract rising male infertility rates, provide safe male gamete-based contraceptives, and preserve biodiversity through improved captive breeding and assisted conception initiatives.
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Affiliation(s)
- Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Carmen Beltran
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Claudia L. Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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38
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Marrone AK, Kucherenko MM, Wiek R, Göpfert MC, Shcherbata HR. Hyperthermic seizures and aberrant cellular homeostasis in Drosophila dystrophic muscles. Sci Rep 2011; 1:47. [PMID: 22355566 PMCID: PMC3216534 DOI: 10.1038/srep00047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 07/14/2011] [Indexed: 11/09/2022] Open
Abstract
In humans, mutations in the Dystrophin Glycoprotein Complex (DGC) cause muscular dystrophies (MDs) that are associated with muscle loss, seizures and brain abnormalities leading to early death. Using Drosophila as a model to study MD we have found that loss of Dystrophin (Dys) during development leads to heat-sensitive abnormal muscle contractions that are repressed by mutations in Dys's binding partner, Dystroglycan (Dg). Hyperthermic seizures are independent from dystrophic muscle degeneration and rely on neurotransmission, which suggests involvement of the DGC in muscle-neuron communication. Additionally, reduction of the Ca(2+) regulator, Calmodulin or Ca(2+) channel blockage rescues the seizing phenotype, pointing to Ca(2+) mis-regulation in dystrophic muscles. Also, Dys and Dg mutants have antagonistically abnormal cellular levels of ROS, suggesting that the DGC has a function in regulation of muscle cell homeostasis. These data show that muscles deficient for Dys are predisposed to hypercontraction that may result from abnormal neuromuscular junction signaling.
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Affiliation(s)
- April K Marrone
- Max Planck Gene Expression and Signaling Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
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39
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Combettes L, Dupont G. [Experimental and computational approach of calcium signaling]. Med Sci (Paris) 2011; 27:170-6. [PMID: 21382325 DOI: 10.1051/medsci/2011272170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In many cell types, specific and robust signalling relies on a high level of spatiotemporal organization of Ca(2+) dynamics. In response to external stimulation, Ca(2+) signals ranging from a small increase of a few tens of nanomolar concentrations at the mouth of an inositol 1, 4, 5-trisphosphate receptor to the periodic propagation of waves invading an organ or a tissue, can be observed. Here, we review our combined experimental and computational approach of Ca(2+) dynamics, which has been mainly carried out on liver hepatocytes. We focus in particular on the understanding of the relationship between elementary Ca(2+) increases, Ca(2+) oscillations and intra- or intercellular Ca(2+) waves. The physiological impact of such signalling on liver function is also discussed.
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40
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Kushnir A, Marks AR. The ryanodine receptor in cardiac physiology and disease. ADVANCES IN PHARMACOLOGY 2010; 59:1-30. [PMID: 20933197 DOI: 10.1016/s1054-3589(10)59001-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
According to the American Heart Association it is estimated that the United States will spend close to $39 billion in 2010 to treat over five million Americans suffering from heart failure. Patients with heart failure suffer from dyspnea and decreased exercised tolerance and are at increased risk for fatal ventricular arrhythmias. Food and Drug Administration -approved pharmacologic therapies for heart failure include diuretics, inhibitors of the renin-angiotensin system, and β-adrenergic receptor antagonists. Over the past 20 years advances in the field of ryanodine receptor (RyR2)/calcium release channel research have greatly advanced our understanding of cardiac physiology and the pathogenesis of heart failure and arrhythmias. Here we review the key observations, controversies, and discoveries that have led to the development of novel compounds targeting the RyR2/calcium release channel for treating heart failure and for preventing lethal arrhythmias.
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Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, College of Physicians and Surgeons of Columbia University, New York, NY, USA
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