51
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Role of protons in calcium signaling. Biochem J 2021; 478:895-910. [PMID: 33635336 DOI: 10.1042/bcj20200971] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 02/03/2023]
Abstract
Thirty-six years after the publication of the important article by Busa and Nuccitelli on the variability of intracellular pH (pHi) and the interdependence of pHi and intracellular Ca2+ concentration ([Ca2+]i), little research has been carried out on pHi and calcium signaling. Moreover, the results appear to be contradictory. Some authors claim that the increase in [Ca2+]i is due to a reduction in pHi, others that it is caused by an increase in pHi. The reasons for these conflicting results have not yet been discussed and clarified in an exhaustive manner. The idea that variations in pHi are insignificant, because cellular buffers quickly stabilize the pHi, may be a limiting and fundamentally wrong concept. In fact, it has been shown that protons can move and react in the cell before they are neutralized. Variations in pHi have a remarkable impact on [Ca2+]i and hence on some of the basic biochemical mechanisms of calcium signaling. This paper focuses on the possible triggering role of protons during their short cellular cycle and it suggests a new hypothesis for an IP3 proton dependent mechanism of action.
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52
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Yamazawa T, Ogawa H, Murayama T, Yamaguchi M, Oyamada H, Suzuki J, Kurebayashi N, Kanemaru K, Oguchi K, Sakurai T, Iino M. Insights into channel modulation mechanism of RYR1 mutants using Ca2+ imaging and molecular dynamics. J Gen Physiol 2021; 152:132759. [PMID: 31841587 PMCID: PMC7034096 DOI: 10.1085/jgp.201812235] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 07/31/2019] [Accepted: 11/05/2019] [Indexed: 12/01/2022] Open
Abstract
Molecular bases of pathogenic enhancement of Ca2+ release channel activities in RYR1 carrying disease-associated mutations at the N-terminal region were studied. Functional studies and MD simulation revealed that the interactions between domains have a strong correlation with channel activity. Type 1 ryanodine receptor (RYR1) is a Ca2+ release channel in the sarcoplasmic reticulum in skeletal muscle and plays an important role in excitation–contraction coupling. Mutations in the RYR1 gene cause severe muscle diseases such as malignant hyperthermia (MH), which is a disorder of CICR via RYR1. Thus far, >300 mutations in RYR1 have been reported in patients with MH. However, owing to a lack of comprehensive analysis of the structure–function relationship of mutant RYR1, the mechanism remains largely unknown. Here, we combined functional studies and molecular dynamics (MD) simulations of RYR1 bearing disease-associated mutations at the N-terminal region. When expressed in HEK293 cells, the mutant RYR1 caused abnormalities in Ca2+ homeostasis. MD simulations of WT and mutant RYR1s were performed using crystal structure of the N-terminal domain (NTD) monomer, consisting of A, B, and C domains. We found that the mutations located around the interdomain region differentially affected hydrogen bonds/salt bridges. Particularly, mutations at R402, which increase the open probability of the channel, cause clockwise rotation of BC domains with respect to the A domain by alteration of the interdomain interactions. Similar results were also obtained with artificial mutations that mimic alteration of the interactions. Our results reveal the importance of interdomain interactions within the NTD in the regulation of the RYR1 channel and provide insights into the mechanism of MH caused by the mutations at the NTD.
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Affiliation(s)
- Toshiko Yamazawa
- Department of Molecular Physiology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Haruo Ogawa
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Takashi Murayama
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Maki Yamaguchi
- Department of Molecular Physiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Hideto Oyamada
- Department of Pharmacology, School of Medicine, Showa University, Tokyo, Japan
| | - Junji Suzuki
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Physiology, University of California, San Francisco, San Francisco, CA
| | - Nagomi Kurebayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Kazunori Kanemaru
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, Japan
| | - Katsuji Oguchi
- Department of Pharmacology, School of Medicine, Showa University, Tokyo, Japan
| | - Takashi Sakurai
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Masamitsu Iino
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, Japan
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53
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Woo JS, Jeong SY, Park JH, Choi JH, Lee EH. Calsequestrin: a well-known but curious protein in skeletal muscle. Exp Mol Med 2020; 52:1908-1925. [PMID: 33288873 PMCID: PMC8080761 DOI: 10.1038/s12276-020-00535-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 12/23/2022] Open
Abstract
Calsequestrin (CASQ) was discovered in rabbit skeletal muscle tissues in 1971 and has been considered simply a passive Ca2+-buffering protein in the sarcoplasmic reticulum (SR) that provides Ca2+ ions for various Ca2+ signals. For the past three decades, physiologists, biochemists, and structural biologists have examined the roles of the skeletal muscle type of CASQ (CASQ1) in skeletal muscle and revealed that CASQ1 has various important functions as (1) a major Ca2+-buffering protein to maintain the SR with a suitable amount of Ca2+ at each moment, (2) a dynamic Ca2+ sensor in the SR that regulates Ca2+ release from the SR to the cytosol, (3) a structural regulator for the proper formation of terminal cisternae, (4) a reverse-directional regulator of extracellular Ca2+ entries, and (5) a cause of human skeletal muscle diseases. This review is focused on understanding these functions of CASQ1 in the physiological or pathophysiological status of skeletal muscle.
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Affiliation(s)
- Jin Seok Woo
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, 10833, USA
| | - Seung Yeon Jeong
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, 06591, Korea
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, 06591, Korea
| | - Ji Hee Park
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, 06591, Korea
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, 06591, Korea
| | - Jun Hee Choi
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, 06591, Korea
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, 06591, Korea
| | - Eun Hui Lee
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul, 06591, Korea.
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, 06591, Korea.
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54
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Pizarro G, Olivera JF. The dynamics of Ca 2+ within the sarcoplasmic reticulum of frog skeletal muscle. A simulation study. J Theor Biol 2020; 504:110371. [PMID: 32533961 DOI: 10.1016/j.jtbi.2020.110371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 06/08/2020] [Accepted: 06/08/2020] [Indexed: 10/24/2022]
Abstract
In skeletal muscle, Ca2+ release from the sarcoplasmic reticulum (SR) triggers contraction. In this study we develop a two compartment model to account for the Ca2+ dynamics in frog skeletal muscle fibers. The two compartments in the model correspond to the SR and the cytoplasm, where the myofibrils are placed. We use a detailed model for the several Ca2+ binding proteins in the cytoplasm in line with previous models. As a new feature, Ca2+ binding sites within the SR, attributed to calsequestrin, are modeled based on experimentally obtained properties. The intra SR Ca2+ buffer shows cooperativity, well represented by a Hill equation with parameters that depend on the initial [Ca2+] in the SR ([Ca2+]SR). The number of total sites as well as the [Ca2+]SR of half saturation are reduced as the resting [Ca2+]SR is reduced, on the other hand the Hill number is not changed. The buffer power remained roughly constant. The release process is activated by a voltage dependent mechanism that increases the Ca2+ permeability of the SR. We use the permeability time course and amplitude experimentally obtained during a voltage clamp pulse to drive the simulations. This model successfully reproduces the SR and cytoplasmic transients observed. Additionally, we simulate [Ca2+] SR transients in the case of high concentration of extrinsic Ca2+ buffers added to the cytoplasm to explore what properties of the permeability are necessary to account for the experimentally observed [Ca2+]SR transients. The main novelty of the model, the intra SR Ca2+ buffer, is crucial for reproducing the experimental observations and it would be of use in future theoretical studies of excitation contraction coupling in skeletal muscle.
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Affiliation(s)
- Gonzalo Pizarro
- Departamento de Biofísica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay. Gral. Flores 2125, Montevideo, CP11800, Uruguay.
| | - J Fernando Olivera
- Departamento de Biofísica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay. Gral. Flores 2125, Montevideo, CP11800, Uruguay.
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55
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Carrasquel-Ursulaez W, Reeves RD, Dehghany M, Jones C, Schomaker JM, Chanda B. Re-evaluation of the mechanism of cytotoxicity of dialkylated lariat ether compounds. RSC Adv 2020; 10:40391-40394. [PMID: 33732448 PMCID: PMC7963367 DOI: 10.1039/d0ra08494h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The cytotoxicity of dialkylated lariat ethers has been previously attributed to their ionophoric properties. Herein, we provide evidence that these effects are due to loss of membrane integrity rather than ion transport, a finding with important implications for the future design of synthetic ionophores. The cytotoxicity of dialkylated lariat ethers has been previously attributed to their ionophoric properties.![]()
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Affiliation(s)
| | - Ryan D Reeves
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Mahzad Dehghany
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Corey Jones
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
| | | | - Baron Chanda
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri 63110, USA
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56
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Evans AM. On a Magical Mystery Tour with 8-Bromo-Cyclic ADP-Ribose: From All-or-None Block to Nanojunctions and the Cell-Wide Web. Molecules 2020; 25:E4768. [PMID: 33081414 PMCID: PMC7587525 DOI: 10.3390/molecules25204768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/08/2020] [Indexed: 11/16/2022] Open
Abstract
A plethora of cellular functions are controlled by calcium signals, that are greatly coordinated by calcium release from intracellular stores, the principal component of which is the sarco/endooplasmic reticulum (S/ER). In 1997 it was generally accepted that activation of various G protein-coupled receptors facilitated inositol-1,4,5-trisphosphate (IP3) production, activation of IP3 receptors and thus calcium release from S/ER. Adding to this, it was evident that S/ER resident ryanodine receptors (RyRs) could support two opposing cellular functions by delivering either highly localised calcium signals, such as calcium sparks, or by carrying propagating, global calcium waves. Coincidentally, it was reported that RyRs in mammalian cardiac myocytes might be regulated by a novel calcium mobilising messenger, cyclic adenosine diphosphate-ribose (cADPR), that had recently been discovered by HC Lee in sea urchin eggs. A reputedly selective and competitive cADPR antagonist, 8-bromo-cADPR, had been developed and was made available to us. We used 8-bromo-cADPR to further explore our observation that S/ER calcium release via RyRs could mediate two opposing functions, namely pulmonary artery dilation and constriction, in a manner seemingly independent of IP3Rs or calcium influx pathways. Importantly, the work of others had shown that, unlike skeletal and cardiac muscles, smooth muscles might express all three RyR subtypes. If this were the case in our experimental system and cADPR played a role, then 8-bromo-cADPR would surely block one of the opposing RyR-dependent functions identified, or the other, but certainly not both. The latter seemingly implausible scenario was confirmed. How could this be, do cells hold multiple, segregated SR stores that incorporate different RyR subtypes in receipt of spatially segregated signals carried by cADPR? The pharmacological profile of 8-bromo-cADPR action supported not only this, but also indicated that intracellular calcium signals were delivered across intracellular junctions formed by the S/ER. Not just one, at least two. This article retraces the steps along this journey, from the curious pharmacological profile of 8-bromo-cADPR to the discovery of the cell-wide web, a diverse network of cytoplasmic nanocourses demarcated by S/ER nanojunctions, which direct site-specific calcium flux and may thus coordinate the full panoply of cellular processes.
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Grants
- 01/A/S/07453 Biotechnology and Biological Sciences Research Council
- WT046374 , WT056423, WT070772, WT074434, WT081195AIA, WT212923, WT093147 Wellcome Trust
- PG/10/95/28657 British Heart Foundation
- FS/03/033/15432, FS/05/050, PG/05/128/19884, RG/12/14/29885, PG/10/95/28657 British Heart Foundation
- RG/12/14/29885 British Heart Foundation
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Affiliation(s)
- A Mark Evans
- Centre for Discovery Brain Sciences and Cardiovascular Science, Edinburgh Medical School, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
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57
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Electrophysiological insights into the relationship between calcium dynamics and cardiomyocyte beating function in chronic hemodialysis treatment. J Artif Organs 2020; 24:58-64. [PMID: 32910365 DOI: 10.1007/s10047-020-01207-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 08/24/2020] [Indexed: 10/23/2022]
Abstract
For patients in which the Ca2+ concentration of dialysis fluid is lower than that in plasma, chronic hemodialysis treatment often leads to cardiac beating dysfunction. By applying these conditions to an electrophysiological mathematical model, we evaluated the impact of body fluid Ca2+ dynamics during treatment on cardiomyocyte beating and, moreover, explored measures that may prevent cardiomyocyte beating dysfunction. First, Ca2+ concentrations in both plasma and interstitial fluid were decreased with treatment time, which induced both a slight decline in beating rhythm on a sinoatrial nodal cell and a wane in contraction force on a ventricular cell. These simulated results were in agreement with clinical observations. Next, a relationship between the intracellular Ca2+ concentration and ion current dynamics of ion transporters were examined to elucidate the mechanism underlying cardiomyocyte beating dysfunction. The inward current of the Na/Ca exchanger (NCX) increased with a decrease in Ca2+ concentration in interstitial fluid and induced a reduction in intracellular Ca2+ concentration during treatment. Furthermore, the decline in intracellular Ca2+ concentration reduced the contraction force. These findings implied that ion transport through the NCX is a dominant factor that induces cardiomyocyte beating dysfunction during hemodialysis. Finally, the replenishment of Ca2+ or application of an NCX inhibitor during treatment suppressed the decrease in intracellular Ca2+ concentration and contributed to the stabilization of cardiomyocyte beating function. In summary, the clinical implementation of hepatically cleared NCX inhibitor may be a suitable approach to improving the quality of life for patients on chronic hemodialysis.
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58
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Zhai X, Sterea AM, El Hiani Y. Lessons from the Endoplasmic Reticulum Ca 2+ Transporters-A Cancer Connection. Cells 2020; 9:E1536. [PMID: 32599788 PMCID: PMC7349521 DOI: 10.3390/cells9061536] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 02/06/2023] Open
Abstract
Ca2+ is an integral mediator of intracellular signaling, impacting almost every aspect of cellular life. The Ca2+-conducting transporters located on the endoplasmic reticulum (ER) membrane shoulder the responsibility of constructing the global Ca2+ signaling landscape. These transporters gate the ER Ca2+ release and uptake, sculpt signaling duration and intensity, and compose the Ca2+ signaling rhythm to accommodate a plethora of biological activities. In this review, we explore the mechanisms of activation and functional regulation of ER Ca2+ transporters in the establishment of Ca2+ homeostasis. We also contextualize the aberrant alterations of these transporters in carcinogenesis, presenting Ca2+-based therapeutic interventions as a means to tackle malignancies.
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Affiliation(s)
- Xingjian Zhai
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada;
| | | | - Yassine El Hiani
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada;
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59
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Wang Q, Michalak M. Calsequestrin. Structure, function, and evolution. Cell Calcium 2020; 90:102242. [PMID: 32574906 DOI: 10.1016/j.ceca.2020.102242] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/05/2020] [Accepted: 06/06/2020] [Indexed: 12/25/2022]
Abstract
Calsequestrin is the major Ca2+ binding protein in the sarcoplasmic reticulum (SR), serves as the main Ca2+ storage and buffering protein and is an important regulator of Ca2+ release channels in both skeletal and cardiac muscle. It is anchored at the junctional SR membrane through interactions with membrane proteins and undergoes reversible polymerization with increasing Ca2+ concentration. Calsequestrin provides high local Ca2+ at the junctional SR and communicates changes in luminal Ca2+ concentration to Ca2+ release channels, thus it is an essential component of excitation-contraction coupling. Recent studies reveal new insights on calsequestrin trafficking, Ca2+ binding, protein evolution, protein-protein interactions, stress responses and the molecular basis of related human muscle disease, including catecholaminergic polymorphic ventricular tachycardia (CPVT). Here we provide a comprehensive overview of calsequestrin, with recent advances in structure, diverse functions, phylogenetic analysis, and its role in muscle physiology, stress responses and human pathology.
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Affiliation(s)
- Qian Wang
- Department of Biochemistry, University of Alberta, Edmonton, AB, T6H 2S7, Canada
| | - Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, AB, T6H 2S7, Canada.
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60
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Functional analysis of newly identified RYR1 variants in patients susceptible to malignant hyperthermia. J Anesth 2020; 34:658-665. [PMID: 32535660 DOI: 10.1007/s00540-020-02803-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 05/23/2020] [Indexed: 12/19/2022]
Abstract
PURPOSE This study aimed to evaluate whether the three ryanodine receptor type 1 (RYR1) variants (p.Ser2345Thr, p.Ser2345Arg, and p.Lys3367Arg) which we identified in Japanese malignant hyperthermia (MH) patients with a clinical grading scale rank of 6 were causative for MH. METHODS We prepared human embryonic kidney (HEK)-293 cells transfected with wild-type RYR1 or one of the RYR1 variants, along with myotubes cultured from muscle pieces. Calcium kinetics were examined by calculating the 340/380-nm ratio under various caffeine and 4-chloro-m-cresol (4CmC) concentrations with the ratiometric dye Fura-2 AM. Half-maximal effective concentration (EC50) values were calculated from dose-response curves. Statistical analysis was based on one-way analysis of variance with a Dunnett's multiple comparison test, using a P value < 0.05 as evidence of statistical significance. RESULTS In functional analysis using HEK-293 cells, we found significant reductions in the EC50 of p.Ser2345Thr and p.Ser2345Arg in comparison with wild-type RYR1 (P < 0.001), while the EC50 of p.Lys3367Arg was not significantly different (P = 0.062 for caffeine and P > 0.999 for 4CmC). On the other hand, functional analysis using myotubes showed significant differences in the EC50 values for all variants (P < 0.001 for all comparisons). CONCLUSIONS p.Ser2345Thr and p.Ser2345Arg appear capable of causing a calcium metabolism disorder that leads to the onset of MH, and p.Ser2345Arg can be considered as a diagnostic mutation, because it meets the European Malignant Hyperthermia Group criteria. However, patients with p.Lys3367Arg might have mutations in genes other than RYR1 that are capable of causing MH.
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Ishii S, Oyama K, Shintani SA, Kobirumaki-Shimozawa F, Ishiwata S, Fukuda N. Thermal Activation of Thin Filaments in Striated Muscle. Front Physiol 2020; 11:278. [PMID: 32372968 PMCID: PMC7179743 DOI: 10.3389/fphys.2020.00278] [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: 01/16/2020] [Accepted: 03/12/2020] [Indexed: 01/02/2023] Open
Abstract
In skeletal and cardiac muscles, contraction is triggered by an increase in the intracellular Ca2+ concentration. During Ca2+ transients, Ca2+-binding to troponin C shifts the "on-off" equilibrium of the thin filament state toward the "on" sate, promoting actomyosin interaction. Likewise, recent studies have revealed that the thin filament state is under the influence of temperature; viz., an increase in temperature increases active force production. In this short review, we discuss the effects of temperature on the contractile performance of mammalian striated muscle at/around body temperature, focusing especially on the temperature-dependent shift of the "on-off" equilibrium of the thin filament state.
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Affiliation(s)
- Shuya Ishii
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
- Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, Gunma, Japan
| | - Kotaro Oyama
- Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, Gunma, Japan
- PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Seine A. Shintani
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Japan
| | | | - Shin’ichi Ishiwata
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| | - Norio Fukuda
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
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Carbon Monoxide, a Retrograde Messenger Generated in Postsynaptic Mushroom Body Neurons, Evokes Noncanonical Dopamine Release. J Neurosci 2020; 40:3533-3548. [PMID: 32253360 DOI: 10.1523/jneurosci.2378-19.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/12/2020] [Accepted: 03/19/2020] [Indexed: 02/06/2023] Open
Abstract
Dopaminergic neurons innervate extensive areas of the brain and release dopamine (DA) onto a wide range of target neurons. However, DA release is also precisely regulated. In Drosophila melanogaster brain explant preparations, DA is released specifically onto α3/α'3 compartments of mushroom body (MB) neurons that have been coincidentally activated by cholinergic and glutamatergic inputs. The mechanism for this precise release has been unclear. Here we found that coincidentally activated MB neurons generate carbon monoxide (CO), which functions as a retrograde signal evoking local DA release from presynaptic terminals. CO production depends on activity of heme oxygenase in postsynaptic MB neurons, and CO-evoked DA release requires Ca2+ efflux through ryanodine receptors in DA terminals. CO is only produced in MB areas receiving coincident activation, and removal of CO using scavengers blocks DA release. We propose that DA neurons use two distinct modes of transmission to produce global and local DA signaling.SIGNIFICANCE STATEMENT Dopamine (DA) is needed for various higher brain functions, including memory formation. However, DA neurons form extensive synaptic connections, while memory formation requires highly specific and localized DA release. Here we identify a mechanism through which DA release from presynaptic terminals is controlled by postsynaptic activity. Postsynaptic neurons activated by cholinergic and glutamatergic inputs generate carbon monoxide, which acts as a retrograde messenger inducing presynaptic DA release. Released DA is required for memory-associated plasticity. Our work identifies a novel mechanism that restricts DA release to the specific postsynaptic sites that require DA during memory formation.
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63
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Lake JA, Abasht B. Glucolipotoxicity: A Proposed Etiology for Wooden Breast and Related Myopathies in Commercial Broiler Chickens. Front Physiol 2020; 11:169. [PMID: 32231585 PMCID: PMC7083144 DOI: 10.3389/fphys.2020.00169] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 02/13/2020] [Indexed: 01/10/2023] Open
Abstract
Wooden breast is one of several myopathies of fast-growing commercial broilers that has emerged as a consequence of intensive selection practices in the poultry breeding industry. Despite the substantial economic burden presented to broiler producers worldwide by wooden breast and related muscle disorders such as white striping, the genetic and etiological underpinnings of these diseases are still poorly understood. Here we propose a new hypothesis on the primary causes of wooden breast that implicates dysregulation of lipid and glucose metabolism. Our hypothesis addresses recent findings that have suggested etiologic similarities between wooden breast and type 2 diabetes despite their phenotypic disparities. Unlike in mammals, dysregulation of lipid and glucose metabolism is not accompanied by an increase in plasma glucose levels but generates a unique skeletal muscle phenotype, i.e., wooden breast, in chickens. We hypothesize that these phenotypic disparities result from a major difference in skeletal muscle glucose transport between birds and mammals, and that the wooden breast phenotype most closely resembles complications of diabetes in smooth and cardiac muscle of mammals. Additional basic research on wooden breast and related muscle disorders in commercial broiler chickens is necessary and can be informative for poultry breeding and production as well as for human health and disease. To inform future studies, this paper reviews the current biological knowledge of wooden breast, outlines the major steps in its proposed pathogenesis, and examines how selection for production traits may have contributed to its prevalence.
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Affiliation(s)
- Juniper A. Lake
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, United States
| | - Behnam Abasht
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, United States
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64
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Margiotta JF, Howard MJ. Cryptochromes Mediate Intrinsic Photomechanical Transduction in Avian Iris and Somatic Striated Muscle. Front Physiol 2020; 11:128. [PMID: 32153427 PMCID: PMC7047837 DOI: 10.3389/fphys.2020.00128] [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: 12/06/2019] [Accepted: 02/06/2020] [Indexed: 01/12/2023] Open
Abstract
Irises isolated from the eyes of diverse species constrict when exposed to light. Depending on species this intrinsic photomechanical transduction response (PMTR) requires either melanopsin or cryptochrome (CRY) photopigment proteins, generated by their respective association with retinoid or flavin adenine dinucleotide (FAD) chromophores. Although developmentally relevant circadian rhythms are also synchronized and reset by these same proteins, the cell type, mechanism, and specificity of photomechanical transduction (PMT) and its relationship to circadian processes remain poorly understood. Here we show that PMTRs consistent with CRY activation by 430 nm blue light occur in developing chicken iris striated muscle, identify relevant mechanisms, and demonstrate that similar PMTRs occur in striated iris and pectoral muscle fibers, prevented in both cases by knocking down CRY gene transcript levels. Supporting CRY activation, iris PMTRs were reduced by inhibiting flavin reductase, but unaffected by melanopsin antagonism. The largest iris PMTRs paralleled the developmental predominance of striated over smooth muscle fibers, and shared their requirement for extracellular Ca2+ influx and release of intracellular Ca2+. Photo-stimulation of identified striated myotubes maintained in dissociated culture revealed the cellular and molecular bases of PMT. Myotubes in iris cell cultures responded to 435 nm light with increased intracellular Ca2+ and contractions, mimicking iris PMTRs and their spectral sensitivity. Interestingly PMTRs featuring contractions and requiring extracellular Ca2+ influx and release of intracellular Ca2+ were also displayed by striated myotubes derived from pectoral muscle. Consistent with these findings, cytosolic CRY1 and CRY2 proteins were detected in both iris and pectoral myotubes, and knocking down myotube CRY1/CRY2 gene transcript levels specifically blocked PMTRs in both cases. Thus CRY-mediated PMT is not unique to iris, but instead reflects a more general feature of developing striated muscle fibers. Because CRYs are core timing components of circadian clocks and CRY2 is critical for circadian regulation of myogenic differentiation CRY-mediated PMT may interact with cell autonomous clocks to influence the progression of striated muscle development.
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Affiliation(s)
- Joseph F Margiotta
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Marthe J Howard
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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65
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Kawano H, Mitchell SB, Koh JY, Goodman KM, Harata NC. Calcium-induced calcium release in noradrenergic neurons of the locus coeruleus. Brain Res 2020; 1729:146627. [PMID: 31883849 DOI: 10.1016/j.brainres.2019.146627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/19/2019] [Accepted: 12/24/2019] [Indexed: 12/11/2022]
Abstract
The locus coeruleus (LC) is a nucleus within the brainstem that consists of norepinephrine-releasing neurons. It is involved in broad processes including cognitive and emotional functions. Understanding the mechanisms that control the excitability of LC neurons is important because they innervate widespread brain regions. One of the key regulators is cytosolic calcium concentration ([Ca2+]c), the increases in which can be amplified by calcium-induced calcium release (CICR) from intracellular calcium stores. Although the electrical activities of LC neurons are regulated by changes in [Ca2+]c, the extent of CICR involvement in this regulation has remained unclear. Here we show that CICR hyperpolarizes acutely dissociated LC neurons of the rat and demonstrate the underlying pathway. When CICR was activated by extracellular application of 10 mM caffeine, LC neurons were hyperpolarized in the current-clamp mode of patch-clamp recording, and the majority of neurons showed an outward current in the voltage-clamp mode. This outward current was accompanied by increased membrane conductance, and its reversal potential was close to the K+ equilibrium potential, indicating that it is mediated by opening of K+ channels. The outward current was generated in the absence of extracellular calcium and was blocked when the calcium stores were inhibited by applying ryanodine. Pharmacological blockers indicated that it was mediated by Ca2+-activated K+ channels of the non-small conductance type. The application of caffeine increased [Ca2+]c, as visualized by fluorescence microscopy. These findings show CICR suppresses LC neuronal activity, and indicate its dynamic role in modulating the LC-mediated noradrenergic tone in the brain.
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Affiliation(s)
- Hiroyuki Kawano
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Sara B Mitchell
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Jin-Young Koh
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology-Head and Neck Surgery, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Biomedical Engineering, University of Iowa College of Engineering, Iowa City, IA, USA
| | - Kirsty M Goodman
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Biology & Biochemistry, University of Bath, Bath, UK
| | - N Charles Harata
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
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66
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Rotenberg MY, Elbaz B, Nair V, Schaumann EN, Yamamoto N, Sarma N, Matino L, Santoro F, Tian B. Silicon Nanowires for Intracellular Optical Interrogation with Subcellular Resolution. NANO LETTERS 2020; 20:1226-1232. [PMID: 31904975 PMCID: PMC7513588 DOI: 10.1021/acs.nanolett.9b04624] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Current techniques for intracellular electrical interrogation are limited by substrate-bound devices, technically demanding methods, or insufficient spatial resolution. In this work, we use freestanding silicon nanowires to achieve photoelectric stimulation in myofibroblasts with subcellular resolution. We demonstrate that myofibroblasts spontaneously internalize silicon nanowires and subsequently remain viable and capable of mitosis. We then show that stimulation of silicon nanowires at separate intracellular locations results in local calcium fluxes in subcellular regions. Moreover, nanowire-myofibroblast hybrids electrically couple with cardiomyocytes in coculture, and photostimulation of the nanowires increases the spontaneous activation rate in coupled cardiomyocytes. Finally, we demonstrate that this methodology can be extended to the interrogation of signaling in neuron-glia interactions using nanowire-containing oligodendrocytes.
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Affiliation(s)
| | | | | | | | | | | | - Laura Matino
- Tissue Electronics, Center for Advanced Biomaterials for Healthcare , Istituto Italiano di Tecnologia , 80125 Naples , Italy
- Department of Chemical Materials and Industrial Production Engineering , University of Naples Federico II , 80125 Naples , Italy
| | - Francesca Santoro
- Tissue Electronics, Center for Advanced Biomaterials for Healthcare , Istituto Italiano di Tecnologia , 80125 Naples , Italy
- Department of Chemical Materials and Industrial Production Engineering , University of Naples Federico II , 80125 Naples , Italy
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67
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Ogawa H, Kurebayashi N, Yamazawa T, Murayama T. Regulatory mechanisms of ryanodine receptor/Ca 2+ release channel revealed by recent advancements in structural studies. J Muscle Res Cell Motil 2020; 42:291-304. [PMID: 32040690 PMCID: PMC8332584 DOI: 10.1007/s10974-020-09575-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/05/2020] [Indexed: 02/07/2023]
Abstract
Ryanodine receptors (RyRs) are huge homotetrameric Ca2+ release channels localized to the sarcoplasmic reticulum. RyRs are responsible for the release of Ca2+ from the SR during excitation–contraction coupling in striated muscle cells. Recent revolutionary advancements in cryo-electron microscopy have provided a number of near-atomic structures of RyRs, which have enabled us to better understand the architecture of RyRs. Thus, we are now in a new era understanding the gating, regulatory and disease-causing mechanisms of RyRs. Here we review recent advances in the elucidation of the structures of RyRs, especially RyR1 in skeletal muscle, and their mechanisms of regulation by small molecules, associated proteins and disease-causing mutations.
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Affiliation(s)
- Haruo Ogawa
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan.
| | - Nagomi Kurebayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, 113-8421, Japan
| | - Toshiko Yamazawa
- Department of Molecular Physiology, The Jikei University School of Medicine, Tokyo, 105-8461, Japan
| | - Takashi Murayama
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, 113-8421, Japan
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68
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Arow M, Waldman M, Yadin D, Nudelman V, Shainberg A, Abraham NG, Freimark D, Kornowski R, Aravot D, Hochhauser E, Arad M. Sodium-glucose cotransporter 2 inhibitor Dapagliflozin attenuates diabetic cardiomyopathy. Cardiovasc Diabetol 2020; 19:7. [PMID: 31924211 PMCID: PMC6953156 DOI: 10.1186/s12933-019-0980-4] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 12/24/2019] [Indexed: 02/07/2023] Open
Abstract
Background Diabetes mellitus type 2 (DM2) is a risk factor for developing heart failure but there is no specific therapy for diabetic heart disease. Sodium glucose transporter 2 inhibitors (SGLT2I) are recently developed diabetic drugs that primarily work on the kidney. Clinical data describing the cardiovascular benefits of SGLT2Is highlight the potential therapeutic benefit of these drugs in the prevention of cardiovascular events and heart failure. However, the underlying mechanism of protection remains unclear. We investigated the effect of Dapagliflozin—SGLT2I, on diabetic cardiomyopathy in a mouse model of DM2. Methods Cardiomyopathy was induced in diabetic mice (db/db) by subcutaneous infusion of angiotensin II (ATII) for 30 days using an osmotic pump. Dapagliflozin (1.5 mg/kg/day) was administered concomitantly in drinking water. Male homozygous, 12–14 weeks old WT or db/db mice (n = 4–8/group), were used for the experiments. Isolated cardiomyocytes were exposed to glucose (17.5–33 mM) and treated with Dapagliflozin in vitro. Intracellular calcium transients were measured using a fluorescent indicator indo-1. Results Angiotensin II infusion induced cardiomyopathy in db/db mice, manifested by cardiac hypertrophy, myocardial fibrosis and inflammation (TNFα, TLR4). Dapagliflozin decreased blood glucose (874 ± 111 to 556 ± 57 mg/dl, p < 0.05). In addition it attenuated fibrosis and inflammation and increased the left ventricular fractional shortening in ATII treated db/db mice. In isolated cardiomyocytes Dapagliflozin decreased intracellular calcium transients, inflammation and ROS production. Finally, voltage-dependent L-type calcium channel (CACNA1C), the sodium–calcium exchanger (NCX) and the sodium–hydrogen exchanger 1 (NHE) membrane transporters expression was reduced following Dapagliflozin treatment. Conclusion Dapagliflozin was cardioprotective in ATII-stressed diabetic mice. It reduced oxygen radicals, as well the activity of membrane channels related to calcium transport. The cardioprotective effect manifested by decreased fibrosis, reduced inflammation and improved systolic function. The clinical implication of our results suggest a novel pharmacologic approach for the treatment of diabetic cardiomyopathy through modulation of ion homeostasis.
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Affiliation(s)
- M Arow
- Cardiac Research Laboratory, Felsenstein Medical Research Institute Petah-Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Leviev Heart Center, Sheba Medical Center, Tel Hashomer and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - M Waldman
- Cardiac Research Laboratory, Felsenstein Medical Research Institute Petah-Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Leviev Heart Center, Sheba Medical Center, Tel Hashomer and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - D Yadin
- Cardiac Research Laboratory, Felsenstein Medical Research Institute Petah-Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Leviev Heart Center, Sheba Medical Center, Tel Hashomer and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - V Nudelman
- Cardiac Research Laboratory, Felsenstein Medical Research Institute Petah-Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - N G Abraham
- Pharmacology Department, New York Medical College, Valhalla, NY, 10595, USA
| | - D Freimark
- Leviev Heart Center, Sheba Medical Center, Tel Hashomer and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - R Kornowski
- Cardiac Research Laboratory, Felsenstein Medical Research Institute Petah-Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - D Aravot
- Cardiac Research Laboratory, Felsenstein Medical Research Institute Petah-Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - E Hochhauser
- Cardiac Research Laboratory, Felsenstein Medical Research Institute Petah-Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - M Arad
- Leviev Heart Center, Sheba Medical Center, Tel Hashomer and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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69
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Murayama T, Kurebayashi N. Assays for Modulators of Ryanodine Receptor (RyR)/Ca
2+
Release Channel Activity for Drug Discovery for Skeletal Muscle and Heart Diseases. ACTA ACUST UNITED AC 2019; 87:e71. [DOI: 10.1002/cpph.71] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Takashi Murayama
- Department of PharmacologyJuntendo University School of Medicine Tokyo Japan
| | - Nagomi Kurebayashi
- Department of PharmacologyJuntendo University School of Medicine Tokyo Japan
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70
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Yamaguchi N. Molecular Insights into Calcium Dependent Regulation of Ryanodine Receptor Calcium Release Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1131:321-336. [DOI: 10.1007/978-3-030-12457-1_13] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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71
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Yin S, Liu J, Kang Y, Lin Y, Li D, Shao L. Interactions of nanomaterials with ion channels and related mechanisms. Br J Pharmacol 2019; 176:3754-3774. [PMID: 31290152 DOI: 10.1111/bph.14792] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 06/10/2019] [Accepted: 07/01/2019] [Indexed: 12/15/2022] Open
Abstract
The pharmacological potential of nanotechnology, especially in drug delivery and bioengineering, has developed rapidly in recent decades. Ion channels, which are easily targeted by external agents, such as nanomaterials (NMs) and synthetic drugs, due to their unique structures, have attracted increasing attention in the fields of nanotechnology and pharmacology for the treatment of ion channel-related diseases. NMs have significant effects on ion channels, and these effects are manifested in many ways, including changes in ion currents, kinetic characteristics and channel distribution. Subsequently, intracellular ion homeostasis, signalling pathways, and intracellular ion stores are affected, leading to the initiation of a range of biological processes. However, the effect of the interactions of NMs with ion channels is an interesting topic that remains obscure. In this review, we have summarized the recent research progress on the direct and indirect interactions between NMs and ion channels and discussed the related molecular mechanisms, which are crucial to the further development of ion channel-related nanotechnological applications.
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Affiliation(s)
- Suhan Yin
- Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Biomaterials Research Center, School of Biomedical Engineering, Southern Medical University, Guangzhou, 510515, China
| | - Jia Liu
- Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yiyuan Kang
- Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuqing Lin
- Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Dongjian Li
- Liwan District Stomatology Hospital, Guangzhou, China
| | - Longquan Shao
- Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Biomaterials Research Center, School of Biomedical Engineering, Southern Medical University, Guangzhou, 510515, China
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72
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Fatima M, Brennan-Olsen SL, Duque G. Therapeutic approaches to osteosarcopenia: insights for the clinician. Ther Adv Musculoskelet Dis 2019; 11:1759720X19867009. [PMID: 31431811 PMCID: PMC6686316 DOI: 10.1177/1759720x19867009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 07/06/2019] [Indexed: 12/19/2022] Open
Abstract
Osteopenia/osteoporosis and sarcopenia are both age-related conditions. Given the well-defined bone and muscle interaction, when osteopenia and sarcopenia occur simultaneously, this geriatric syndrome is defined as ‘osteosarcopenia’. Evidence exists about therapeutic interventions common to both bone and muscle, which could thereby be effective in treating osteosarcopenia. In addition, there are roles for common nonpharmacological strategies such as nutritional intervention and physical exercise prescription in the management of this condition. In this review we summarize the evidence on current and upcoming therapeutic approaches to osteosarcopenia.
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Affiliation(s)
- Mizhgan Fatima
- Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Sharon L Brennan-Olsen
- Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, St Albans, VIC, Australia
| | - Gustavo Duque
- Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, 176 Furlong Road, St. Albans, VIC 3021, Australia
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73
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Liu C, Spinozzi S, Chen JY, Fang X, Feng W, Perkins G, Cattaneo P, Guimarães-Camboa N, Dalton ND, Peterson KL, Wu T, Ouyang K, Fu XD, Evans SM, Chen J. Nexilin Is a New Component of Junctional Membrane Complexes Required for Cardiac T-Tubule Formation. Circulation 2019; 140:55-66. [PMID: 30982350 PMCID: PMC6889818 DOI: 10.1161/circulationaha.119.039751] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 04/02/2019] [Indexed: 01/03/2023]
Abstract
BACKGROUND Membrane contact sites are fundamental for transmission and translation of signals in multicellular organisms. The junctional membrane complexes in the cardiac dyads, where transverse (T) tubules are juxtaposed to the sarcoplasmic reticulum, are a prime example. T-tubule uncoupling and remodeling are well-known features of cardiac disease and heart failure. Even subtle alterations in the association between T-tubules and the junctional sarcoplasmic reticulum can cause serious cardiac disorders. NEXN (nexilin) has been identified as an actin-binding protein, and multiple mutations in the NEXN gene are associated with cardiac diseases, but the precise role of NEXN in heart function and disease is still unknown. METHODS Nexn global and cardiomyocyte-specific knockout mice were generated. Comprehensive phenotypic and RNA sequencing and mass spectrometry analyses were performed. Heart tissue samples and isolated single cardiomyocytes were analyzed by electron and confocal microscopy. RESULTS Global and cardiomyocyte-specific loss of Nexn in mice resulted in a rapidly progressive dilated cardiomyopathy. In vivo and in vitro analyses revealed that NEXN interacted with junctional sarcoplasmic reticulum proteins, was essential for optimal calcium transients, and was required for initiation of T-tubule invagination and formation. CONCLUSIONS These results demonstrated that NEXN is a pivotal component of the junctional membrane complex and is required for initiation and formation of T-tubules, thus providing insight into mechanisms underlying cardiomyopathy in patients with mutations in NEXN.
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MESH Headings
- Animals
- Calcium Channels, L-Type/metabolism
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cardiomyopathy, Dilated/pathology
- Cell Membrane/genetics
- Cell Membrane/metabolism
- Cell Membrane/pathology
- Cells, Cultured
- Intercellular Junctions/genetics
- Intercellular Junctions/metabolism
- Intercellular Junctions/pathology
- Mice
- Mice, Knockout
- Mice, Transgenic
- Microfilament Proteins/deficiency
- Microfilament Proteins/genetics
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
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Affiliation(s)
- Canzhao Liu
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Simone Spinozzi
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Jia-Yu Chen
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Xi Fang
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Wei Feng
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Guy Perkins
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, CA 92093, USA
| | - Paola Cattaneo
- National Research Council, Institute of Genetics and Biomedical Research, Milan 20138, Italy
- Humanitas Clinical and Research Center, Rozzano 20089, Italy
| | - Nuno Guimarães-Camboa
- Institute for Cardiovascular Regeneration, Centre of Molecular Medicine, Goethe University Frankfurt, 60590 Frankfurt, Germany
- German Center for Cardiovascular Research DZHK, Berlin 13347, Germany
| | - Nancy D. Dalton
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Kirk L. Peterson
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Tongbin Wu
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Kunfu Ouyang
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Institute of Genomic Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Sylvia M. Evans
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Ju Chen
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
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Aoi W, Hirano N, Lassiter DG, Björnholm M, Chibalin AV, Sakuma K, Tanimura Y, Mizushima K, Takagi T, Naito Y, Zierath JR, Krook A. Secreted protein acidic and rich in cysteine (SPARC) improves glucose tolerance via AMP-activated protein kinase activation. FASEB J 2019; 33:10551-10562. [PMID: 31225998 DOI: 10.1096/fj.201900453r] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
During exercise, skeletal muscles release cytokines, peptides, and metabolites that exert autocrine, paracrine, or endocrine effects on glucose homeostasis. In this study, we investigated the effects of secreted protein acidic and rich in cysteine (SPARC), an exercise-responsive myokine, on glucose metabolism in human and mouse skeletal muscle. SPARC-knockout mice showed impaired systemic metabolism and reduced phosphorylation of AMPK and protein kinase B in skeletal muscle. Treatment of SPARC-knockout mice with recombinant SPARC improved glucose tolerance and concomitantly activated AMPK in skeletal muscle. These effects were dependent on AMPK-γ3 because SPARC treatment enhanced skeletal muscle glucose uptake in wild-type mice but not in AMPK-γ3-knockout mice. SPARC strongly interacted with the voltage-dependent calcium channel, and inhibition of calcium-dependent signaling prevented SPARC-induced AMPK phosphorylation in human and mouse myotubes. Finally, chronic SPARC treatment improved systemic glucose tolerance and AMPK signaling in skeletal muscle of high-fat diet-induced obese mice, highlighting the efficacy of SPARC treatment in the management of metabolic diseases. Thus, our findings suggest that SPARC treatment mimics the effects of exercise on glucose tolerance by enhancing AMPK-dependent glucose uptake in skeletal muscle.-Aoi, W., Hirano, N., Lassiter, D. G., Björnholm, M., Chibalin, A. V., Sakuma, K., Tanimura, Y., Mizushima, K., Takagi, T., Naito, Y., Zierath, J. R., Krook, A. Secreted protein acidic and rich in cysteine (SPARC) improves glucose tolerance via AMP-activated protein kinase activation.
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Affiliation(s)
- Wataru Aoi
- Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Nariyuki Hirano
- Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - David G Lassiter
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Marie Björnholm
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Kunihiro Sakuma
- Institute for Liberal Arts, School of Environment and Society, Tokyo Institute of Technology, Tokyo, Japan
| | - Yuko Tanimura
- Faculty of Human, Aichi-Toho University, Nagoya, Japan
| | - Katsura Mizushima
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomohisa Takagi
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuji Naito
- Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Juleen R Zierath
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Anna Krook
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Grassi F, Fucile S. Calcium influx through muscle nAChR-channels: One route, multiple roles. Neuroscience 2019; 439:117-124. [PMID: 30999028 DOI: 10.1016/j.neuroscience.2019.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/01/2019] [Accepted: 04/04/2019] [Indexed: 01/31/2023]
Abstract
Although Ca2+ influx through muscle nAChR-channels has been described over the past 40 years, its functions remain still poorly understood. In this review we suggest possible roles of Ca2+ entry at all stages of muscle development, summarizing the evidence present in literature. nAChRs are expressed in myoblasts prior to fusion, and can be activated in the absence of an ACh-releasing nerve terminal, with Ca2+ influx likely contributing to regulate cell fusion. Upon establishment of nerve-muscle contact, Ca2+ influx contributes to orchestrate the signaling required for the correct formation of the neuromuscular junction. Finally, in the mature synapse, Ca2+ entry through postsynaptic nAChR-channels - highly Ca2+ permeable, in particular in humans - acts on K+ and Na+ channels to shape endplate excitability. However, when genetic defects cause excessive channel activation, Ca2+ influx becomes toxic and causes endplate myopathy. Throughout the review, we highlight how Ricardo Miledi has contributed to construct this whole body of knowledge, from the initial description of Ca2+ permeability of endplate nAChR channels, to the rationale for the treatment of endplate excitotoxic damage under pathological conditions. This article is part of a Special Issue entitled: SI: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Francesca Grassi
- Department of Physiology and Pharmacology, Sapienza University, piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - Sergio Fucile
- Department of Physiology and Pharmacology, Sapienza University, piazzale Aldo Moro 5, 00185, Rome, Italy; IRCCS Neuromed, Viale dell'Elettronica, 86077, Pozzilli, Italy
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Tang H, Shrager JB. The Signaling Network Resulting in Ventilator-induced Diaphragm Dysfunction. Am J Respir Cell Mol Biol 2019; 59:417-427. [PMID: 29768017 DOI: 10.1165/rcmb.2018-0022tr] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mechanical ventilation (MV) is a life-saving measure for those incapable of adequately ventilating or oxygenating without assistance. Unfortunately, even brief periods of MV result in diaphragm weakness (i.e., ventilator-induced diaphragm dysfunction [VIDD]) that may render it difficult to wean the ventilator. Prolonged MV is associated with cascading complications and is a strong risk factor for death. Thus, prevention of VIDD may have a dramatic impact on mortality rates. Here, we summarize the current understanding of the pathogenic events underlying VIDD. Numerous alterations have been proven important in both human and animal MV diaphragm. These include protein degradation via the ubiquitin proteasome system, autophagy, apoptosis, and calpain activity-all causing diaphragm muscle fiber atrophy, altered energy supply via compromised oxidative phosphorylation and upregulation of glycolysis, and also mitochondrial dysfunction and oxidative stress. Mitochondrial oxidative stress in fact appears to be a central factor in each of these events. Recent studies by our group and others indicate that mitochondrial function is modulated by several signaling molecules, including Smad3, signal transducer and activator of transcription 3, and FoxO. MV rapidly activates Smad3 and signal transducer and activator of transcription 3, which upregulate mitochondrial oxidative stress. Additional roles may be played by angiotensin II and leaky ryanodine receptors causing elevated calcium levels. We present, here, a hypothetical scaffold for understanding the molecular pathogenesis of VIDD, which links together these elements. These pathways harbor several drug targets that could soon move toward testing in clinical trials. We hope that this review will shape a short list of the most promising candidates.
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Affiliation(s)
- Huibin Tang
- Stanford University School of Medicine, Division of Thoracic Surgery, Department of Cardiothoracic Surgery, Stanford, California; and Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
| | - Joseph B Shrager
- Stanford University School of Medicine, Division of Thoracic Surgery, Department of Cardiothoracic Surgery, Stanford, California; and Veterans Affairs Palo Alto Healthcare System, Palo Alto, California
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77
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Reyes-Corral M, Sørensen NM, Thrasivoulou C, Dasgupta P, Ashmore JF, Ahmed A. Differential Free Intracellular Calcium Release by Class II Antiarrhythmics in Cancer Cell Lines. J Pharmacol Exp Ther 2019; 369:152-162. [PMID: 30655298 DOI: 10.1124/jpet.118.254375] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 01/02/2019] [Indexed: 12/31/2022] Open
Abstract
Class II antiarrhythmics or β-blockers are antisympathetic nervous system agents that act by blocking β-adrenoceptors. Despite their common clinical use, little is known about the effects of β-blockers on free intracellular calcium (Ca2+ i), an important cytosolic second messenger and a key regulator of cell function. We investigated the role of four chemical analogs, commonly prescribed β-blockers (atenolol, metoprolol, propranolol, and sotalol), on Ca2+ i release and whole-cell currents in mammalian cancer cells (PC3 prostate cancer and MCF7 breast cancer cell lines). We discovered that only propranolol activated free Ca2+ i release with distinct kinetics, whereas atenolol, metoprolol, and sotalol did not. The propranolol-induced Ca2+ i release was significantly inhibited by the chelation of extracellular calcium with ethylene glycol tetraacetic acid (EGTA) and by dantrolene, an inhibitor of the endoplasmic reticulum (ER) ryanodine receptor channels, and it was completely abolished by 2-aminoethoxydiphenyl borate, an inhibitor of the ER inositol-1,4,5-trisphosphate (IP3) receptor channels. Exhaustion of ER stores with 4-chloro-m-cresol, a ryanodine receptor activator, or thapsigargin, a sarco/ER Ca2+ ATPase inhibitor, precluded the propranolol-induced Ca2+ i release. Finally, preincubation of cells with sotalol or timolol, nonselective blockers of β-adrenoceptors, also reduced the Ca2+ i release activated by propranolol. Our results show that different β-blockers have differential effects on whole-cell currents and free Ca2+ i release and that propranolol activates store-operated Ca2+ i release via a mechanism that involves calcium-induced calcium release and putative downstream transducers such as IP3 The differential action of class II antiarrhythmics on Ca2+ i release may have implications on the pharmacology of these drugs.
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Affiliation(s)
- Marta Reyes-Corral
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Naja M Sørensen
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Christopher Thrasivoulou
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Prokar Dasgupta
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Jonathan F Ashmore
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
| | - Aamir Ahmed
- Centre for Stem Cells and Regenerative Medicine (M.R.-C., A.A.) and MRC Centre for Transplantation (P.D.), King's College London, London, United Kingdom; Sophion Bioscience A/S, Ballerup, Denmark (N.M.S.); and Departments of Cell and Developmental Biology (C.T.) and Neuroscience, Physiology and Pharmacology, and The Ear Institute (J.F.A.), University College London, London, United Kingdom
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78
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Laha S, Giri PP, Saha A, Gupta PP, De A. Life-threatening Episodes of Malignant Hyperthermia Following Halothane Anesthesia in Three Children: A Case Series and Review of Literature. Indian J Crit Care Med 2019; 23:47-50. [PMID: 31065209 PMCID: PMC6481263 DOI: 10.5005/jp-journals-10071-23112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Malignant hyperthermia (MH) is an inherited, pharmacogenetic disorder of the skeletal muscle, characterized by dangerous hypermetabolic state after anesthesia with succinylcholine and/ or volatile halogenated anesthetic agents, clinically manifested as hyperpyrexia and related complications like tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, rigid muscles, rhabdomyolysis and disseminated intravascular coagulation (DIC). Here we present a series of three cases of MH, admitted in our hospital in a span of 8 months for three different operative procedures to be done under general anesthesia (cleft lip repair, Duhamel's operation for Hirschsprung's disease and surgical repair of development dysplasia of hip), who developed probable hyperthermia owing to Halothane being used as an anesthetic agent. How to cite this article Laha S, Giri PP, Saha A, Gupta PP, De A. Life-threatening Episodes of Malignant Hyperthermia Following Halothane Anesthesia in Three Children: A Case Series and Review of Literature. Indian Journal of Critical Care Medicine, January 2019;23(1):47-50.
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Affiliation(s)
- Somrita Laha
- Department of Pediatric Intensive Care, Institute of Child Health, Kolkata, West Bengal, India
| | - Prabhas P Giri
- Department of Pediatric Intensive Care, Institute of Child Health, Kolkata, West Bengal, India
| | - Agnisekhar Saha
- Department of Pediatric Intensive Care, Institute of Child Health, Kolkata, West Bengal, India
| | - Partha P Gupta
- Department of Pediatric Surgery, Institute of Child Health, Kolkata, West Bengal, India
| | - Anisha De
- Department of Anaesthesia, Institute of Child Health, Kolkata, West Bengal, India
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79
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Eshima H, Tamura Y, Kakehi S, Nakamura K, Kurebayashi N, Murayama T, Kakigi R, Sakurai T, Kawamori R, Watada H. Dysfunction of muscle contraction with impaired intracellular Ca 2+ handling in skeletal muscle and the effect of exercise training in male db/db mice. J Appl Physiol (1985) 2018; 126:170-182. [PMID: 30433865 DOI: 10.1152/japplphysiol.00048.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Type 2 diabetes is characterized by reduced contractile force production and increased fatigability of skeletal muscle. While the maintenance of Ca2+ homeostasis during muscle contraction is a requisite for optimal contractile function, the mechanisms underlying muscle contractile dysfunction in type 2 diabetes are unclear. Here, we investigated skeletal muscle contractile force and Ca2+ flux during contraction and pharmacological stimulation in type 2 diabetic model mice ( db/db mice). Furthermore, we investigated the effect of treadmill exercise training on muscle contractile function. In male db/db mice, muscle contractile force and peak Ca2+ levels were both lower during tetanic stimulation of the fast-twitch muscles, while Ca2+ accumulation was higher after stimulation compared with control mice. While 6 wk of exercise training did not improve glucose tolerance, exercise did improve muscle contractile dysfunction, peak Ca2+ levels, and Ca2+ accumulation following stimulation in male db/db mice. These data suggest that dysfunctional Ca2+ flux may contribute to skeletal muscle contractile dysfunction in type 2 diabetes and that exercise training may be a promising therapeutic approach for dysfunctional skeletal muscle contraction. NEW & NOTEWORTHY The purpose of this study was to examine muscle contractile function and Ca2+ regulation as well as the effect of exercise training in skeletal muscle in obese diabetic mice ( db/db). We observed impairment of muscle contractile force and Ca2+ regulation in a male type 2 diabetic animal model. These dysfunctions in muscle were improved by 6 wk of exercise training.
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Affiliation(s)
- Hiroaki Eshima
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan.,The Japan Society for the Promotion of Science , Tokyo , Japan
| | - Yoshifumi Tamura
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Saori Kakehi
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Kyoko Nakamura
- Department of Physiology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Nagomi Kurebayashi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Ryo Kakigi
- Department of Physiology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Ryuzo Kawamori
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Sportology Center, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Center for Therapeutic Innovations in Diabetes, Juntendo University Graduate School of Medicine , Tokyo , Japan.,Center for Molecular Diabetology, Juntendo University Graduate School of Medicine , Tokyo , Japan
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80
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Xu L, Chirasani VR, Carter JS, Pasek DA, Dokholyan NV, Yamaguchi N, Meissner G. Ca 2+-mediated activation of the skeletal-muscle ryanodine receptor ion channel. J Biol Chem 2018; 293:19501-19509. [PMID: 30341173 DOI: 10.1074/jbc.ra118.004453] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/14/2018] [Indexed: 02/05/2023] Open
Abstract
Cryo-electron micrograph studies recently have identified a Ca2+-binding site in the 2,200-kDa ryanodine receptor ion channel (RyR1) in skeletal muscle. To clarify the role of this site in regulating RyR1 activity, here we applied mutational, electrophysiological, and computational methods. Three amino acid residues that interact directly with Ca2+ were replaced, and these RyR1 variants were expressed in HEK293 cells. Single-site RyR1-E3893Q, -E3893V, -E3967Q, -E3967V, and -T5001A variants and double-site RyR1-E3893Q/E3967Q and -E3893V/E3967V variants displayed cellular Ca2+ release in response to caffeine, which indicated that they retained functionality as caffeine-sensitive, Ca2+-conducting channels in the HEK293 cell system. Using [3H]ryanodine binding and single-channel measurements of membrane isolates, we found that single- and double-site RyR1-E3893 and -E3967 variants are not activated by Ca2+ We also noted that RyR1-E3893Q/E3967Q and -E3893V/E3967V variants maintain caffeine- and ATP-induced activation and that RyR1-E3893Q/E3967Q is inhibited by Mg2+ and elevated Ca2+ RyR1-T5001A exhibited decreased Ca2+ sensitivity compared with WT-RyR1 in single-channel measurements. Computational methods suggested that electrostatic interactions between Ca2+ and negatively charged glutamate residues have a critical role in transducing the functional effects of Ca2+ on RyR1. We conclude that the removal of negative charges in the recently identified RyR1 Ca2+-binding site impairs RyR1 activation by physiological Ca2+ concentrations and results in loss of binding to Ca2+ or reduced Ca2+ affinity of the binding site.
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Affiliation(s)
- Le Xu
- From the Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260
| | - Venkat R Chirasani
- From the Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260.,the Departments of Pharmacology and Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania 17033-0850
| | - Jordan S Carter
- the Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425, and.,the Cardiac Signaling Center, Clemson University, Charleston, South Carolina 29425
| | - Daniel A Pasek
- From the Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260
| | - Nikolay V Dokholyan
- From the Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260.,the Departments of Pharmacology and Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania 17033-0850
| | - Naohiro Yamaguchi
- the Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425, and.,the Cardiac Signaling Center, Clemson University, Charleston, South Carolina 29425
| | - Gerhard Meissner
- From the Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260,
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81
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Nanoscale remodeling of ryanodine receptor cluster size underlies cerebral microvascular dysfunction in Duchenne muscular dystrophy. Proc Natl Acad Sci U S A 2018; 115:E9745-E9752. [PMID: 30181262 PMCID: PMC6187127 DOI: 10.1073/pnas.1804593115] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a hereditary neuromuscular disease that results from mutations in the gene encoding dystrophin. The effects of the disease on cardiac and skeletal muscle have been intensely investigated, but much less is known about how DMD impacts vascular smooth muscle cells (SMCs). Using superresolution nanoscopy, we demonstrate that clusters of ryanodine receptors (RyR2s) on the sarcoplasmic reticulum (SR) of cerebral artery SMCs from the mdx mouse model of DMD are larger compared with controls. Increased RyR2 cluster size is associated with augmented SR Ca2+ release and Ca2+-activated K+ channel activity, resulting in impaired vasoconstriction of cerebral microvessels. Our findings demonstrate that remodeling of RyR2 clusters at the molecular level results in cerebral microvascular dysfunction during DMD. Duchenne muscular dystrophy (DMD) results from mutations in the gene encoding dystrophin which lead to impaired function of skeletal and cardiac muscle, but little is known about the effects of the disease on vascular smooth muscle cells (SMCs). Here we used the mdx mouse model to study the effects of mutant dystrophin on the regulation of cerebral artery and arteriole SMC contractility, focusing on an important Ca2+-signaling pathway composed of type 2 ryanodine receptors (RyR2s) on the sarcoplasmic reticulum (SR) and large-conductance Ca2+-activated K+ (BK) channels on the plasma membrane. Nanoscale superresolution image analysis revealed that RyR2 and BKα were organized into discrete clusters, and that the mean size of RyR2 clusters that colocalized with BKα was larger in SMCs from mdx mice (∼62 RyR2 monomers) than in controls (∼40 RyR2 monomers). We further found that the frequency and signal mass of spontaneous, transient Ca2+-release events through SR RyR2s (“Ca2+ sparks”) were greater in SMCs from mdx mice. Patch-clamp electrophysiological recordings indicated a corresponding increase in Ca2+-dependent BK channel activity. Using pressure myography, we found that cerebral pial arteries and parenchymal arterioles from mdx mice failed to develop appreciable spontaneous myogenic tone. Inhibition of RyRs with tetracaine and blocking of BK channels with paxilline restored myogenic tone to control levels, demonstrating that enhanced RyR and BK channel activity is responsible for the diminished pressure-induced constriction of arteries and arterioles from mdx mice. We conclude that increased size of RyR2 protein clusters in SMCs from mdx mice increases Ca2+ spark and BK channel activity, resulting in cerebral microvascular dysfunction.
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82
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Yoriki K, Kusuki I, Kokabu T, Matsushima H, Koshiba A, Kitawaki J. Successful Laparoscopic Surgery without Neuromuscular Blockade in a Patient with Malignant Hyperthermia Susceptibility. J Minim Invasive Gynecol 2018; 26:567-570. [PMID: 30142382 DOI: 10.1016/j.jmig.2018.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/06/2018] [Accepted: 08/11/2018] [Indexed: 10/28/2022]
Abstract
Malignant hyperthermia (MH) is a life-threatening clinical syndrome of hypermetabolism involving skeletal muscle. Susceptibility to MH is inherited in an autosomal dominant manner. Its common trigger is exposure to volatile anesthetic agents or depolarizing muscle relaxants. Deep neuromuscular blockade using muscle relaxants can improve the quality of surgical conditions and prevent cardiorespiratory adverse events during laparoscopic surgery. Here we report a case of successful laparoscopic surgery under anesthetic management without neuromuscular blockade in an MH-susceptible patient. A 22-year-old woman with a family history of MH underwent laparoscopic excision of ovarian endometrioma under total intravenous anesthesia and a posterior transversus abdominis plane block. The surgery was completed uneventfully. Our experience suggests that this type of anesthetic management is useful when performing laparoscopic surgery in MH-susceptible patients.
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Affiliation(s)
- Kaori Yoriki
- Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science (all authors)
| | - Izumi Kusuki
- Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science (all authors)..
| | - Tetsuya Kokabu
- Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science (all authors)
| | - Hiroshi Matsushima
- Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science (all authors)
| | - Akemi Koshiba
- Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science (all authors)
| | - Jo Kitawaki
- Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, Graduate School of Medical Science (all authors)
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83
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A study of the mechanisms of excitation–contraction coupling in frog skeletal muscle based on measurements of [Ca2+] transients inside the sarcoplasmic reticulum. J Muscle Res Cell Motil 2018; 39:41-60. [DOI: 10.1007/s10974-018-9497-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/16/2018] [Indexed: 10/28/2022]
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84
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Murayama T, Ogawa H, Kurebayashi N, Ohno S, Horie M, Sakurai T. A tryptophan residue in the caffeine-binding site of the ryanodine receptor regulates Ca 2+ sensitivity. Commun Biol 2018; 1:98. [PMID: 30271978 PMCID: PMC6123685 DOI: 10.1038/s42003-018-0103-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 07/02/2018] [Indexed: 11/11/2022] Open
Abstract
Ryanodine receptors (RyRs) are Ca2+ release channels in the sarcoplasmic reticulum of skeletal and cardiac muscles and are essential for muscle contraction. Mutations in genes encoding RyRs cause various muscle and arrhythmogenic heart diseases. Although RyR channels are activated by Ca2+, the actual mechanism of Ca2+ binding remains largely unknown. Here, we report the molecular basis of Ca2+ binding to RyRs for channel activation and discuss its implications in disease states. RyR1 and RyR2 carrying mutations in putative Ca2+ and caffeine-binding sites were functionally analysed. The results were interpreted with respect to recent near-atomic resolution RyR1 structures in various ligand states. We demonstrate that a tryptophan residue in the caffeine-binding site controls the structure of the Ca2+-binding site to regulate the Ca2+ sensitivity. Our results reveal the initial step of RyR channel activation by Ca2+ and explain the molecular mechanism of Ca2+ sensitization by caffeine and disease-causing mutations. Takashi Murayama et al. report the molecular basis of calcium binding to ryanodine receptors, a process essential for muscle contraction. They find that a tryptophan residue in the caffeine binding site controls the structure of the calcium binding site, affecting calcium sensitivity.
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Affiliation(s)
- Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, 113-8421, Japan.
| | - Haruo Ogawa
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Nagomi Kurebayashi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, 113-8421, Japan
| | - Seiko Ohno
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan.,Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Suita, Osaka, 565-8565, Japan
| | - Minoru Horie
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, 113-8421, Japan
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85
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Singal A, Mattison LM, Soule CL, Iaizzo PA. Effects of Ablation (Radio Frequency, Cryo, Microwave) on Physiologic Properties of the Human Vastus Lateralis. IEEE Trans Biomed Eng 2018; 65:2202-2209. [PMID: 29989956 DOI: 10.1109/tbme.2017.2787041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Ablative treatments can sometimes cause collateral injury to surrounding muscular tissue, with important clinical implications. In this study, we investigated the changes in muscle physiology of the human vastus lateralis when exposed to three different ablation modalities: radiofrequency ablation, cryoablation, and microwave ablation. METHODS We obtained fresh vastus lateralis tissue biopsy specimens from nine patients (age range: 29-73 years) who were undergoing in vitro contracture testing for malignant hyperthermia. Using leftover waste tissue, we prepared 46 muscle bundles that were utilized in tissue baths before and after ablation. RESULTS After ablation with all the three modalities, we noted dose-dependent sustained reductions in peak force (strength of contraction), as well as transient increases in baseline force (resting muscle tension). But, over the subsequent 3-h recovery period, peak force improved and the baseline force consistently recovered to below its preablation levels. CONCLUSION The novel in vitro methodologies we developed to investigate changes in muscle physiology after ablation can be used to study a spectrum of ablation modalities and also to make head-to-head comparisons of different ablation modalities. SIGNIFICANCE As the role of ablative treatments continues to expand, our findings provide unique insights into the resulting changes in muscle physiology. These insights could enhance the safety and efficacy of ablations and help individuals design and develop novel medical devices.
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86
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Agrawal A, Suryakumar G, Rathor R. Role of defective Ca 2+ signaling in skeletal muscle weakness: Pharmacological implications. J Cell Commun Signal 2018; 12:645-659. [PMID: 29982883 DOI: 10.1007/s12079-018-0477-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/27/2018] [Indexed: 01/19/2023] Open
Abstract
The misbehaving attitude of Ca2+ signaling pathways could be the probable reason in many muscular disorders such as myopathies, systemic disorders like hypoxia, sepsis, cachexia, sarcopenia, heart failure, and dystrophy. The present review throws light upon the calcium flux regulating signaling channels like ryanodine receptor complex (RyR1), SERCA (Sarco-endoplasmic Reticulum Calcium ATPase), DHPR (Dihydropyridine Receptor) or Cav1.1 and Na+/Ca2+ exchange pump in detail and how remodelling of these channels contribute towards disturbed calcium homeostasis. Understanding these pathways will further provide an insight for establishing new therapeutic approaches for the prevention and treatment of muscle atrophy under stress conditions, targeting calcium ion channels and associated regulatory proteins.
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Affiliation(s)
- Akanksha Agrawal
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Geetha Suryakumar
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India
| | - Richa Rathor
- DRDO, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054, India.
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87
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Lei W, Ni J, Xia X, Jiang M, Bai G. Searching for synergistic calcium antagonists and novel therapeutic regimens for coronary heart disease therapy from a Traditional Chinese Medicine, Suxiao Jiuxin Pill. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1092:220-227. [PMID: 29908471 DOI: 10.1016/j.jchromb.2018.06.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 12/23/2022]
Abstract
Coronary heart disease is a vital cause of morbidity and mortality worldwide, and calcium channel blockers (CCBs) are important drugs that can be used to treat cardiovascular diseases. Suxiao Jiuxin Pill (SX), a traditional Chinese medicine, is widely used as an emergency drug for coronary heart disease therapy. However, understanding its potential mechanism in intracellular calcium concentration ([Ca2+]i) modulation remains a challenge. To identify the active pharmacological ingredients (APIs) and reveal a novel combination therapy for ameliorating cardiovascular diseases, the ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) combined with a dual-luciferase reporter [Ca2+]i assay system was applied. Ligustrazine, ferulic acid, senkyunolide I, senkyunolide A and ligustilide were identified as potential calcium antagonists in SX, and the combination of ligustrazine and senkyunolide A showed synergetic calcium antagonistic activity. Additionally, the synergetic mechanism was further investigated by live-imaging analysis with the Ca2+ indicator fluo-4/AM by monitoring fluorescence changes. Our results indicated that ligustrazine can block voltage-operated Ca2+ channels (VDCCs) effectively and senkyunolide A can exert an inhibition effect mostly on ryanodine receptors (RYRs) and partly on VDCCs. Finally, an arterial ring assay showed that the combination of ligustrazine and senkyunolide A exerted a better vasodilatation function than using any components alone. In this study, we first revealed that a pair of natural APIs in combination acting on VDCCs and RYRs was more effective on vasodilatation by regulating [Ca2+]i.
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Affiliation(s)
- Wei Lei
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, People's Republic of China
| | - Jianan Ni
- College of Traditional Chinese Medicine, Tianjing University of Traditional Chinese Medicine, Tianjin 300193, People's Republic of China
| | - Xueting Xia
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, People's Republic of China
| | - Min Jiang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, People's Republic of China.
| | - Gang Bai
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, People's Republic of China.
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88
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Allard B. From excitation to intracellular Ca 2+ movements in skeletal muscle: Basic aspects and related clinical disorders. Neuromuscul Disord 2018; 28:394-401. [DOI: 10.1016/j.nmd.2018.03.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/19/2018] [Accepted: 03/05/2018] [Indexed: 01/18/2023]
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89
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Abstract
Ryanodine-sensitive intracellular Ca2+ channels (RyRs) open upon binding Ca2+ at cytosolic-facing sites. This results in concerted, self-reinforcing opening of RyRs clustered in specialized regions on the membranes of Ca2+ storage organelles (endoplasmic reticulum and sarcoplasmic reticulum), a process that produces Ca2+-induced Ca2+ release (CICR). The process is optimized to achieve large but brief and localized increases in cytosolic Ca2+ concentration, a feature now believed to be critical for encoding the multiplicity of signals conveyed by this ion. In this paper, I trace the path of research that led to a consensus on the physiological significance of CICR in skeletal muscle, beginning with its discovery. I focus on the approaches that were developed to quantify the contribution of CICR to the Ca2+ increase that results in contraction, as opposed to the flux activated directly by membrane depolarization (depolarization-induced Ca2+ release [DICR]). Although the emerging consensus is that CICR plays an important role alongside DICR in most taxa, its contribution in most mammalian muscles appears to be limited to embryogenesis. Finally, I survey the relevance of CICR, confirmed or plausible, to pathogenesis as well as the multiple questions about activation of release channels that remain unanswered after 50 years.
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Affiliation(s)
- Eduardo Ríos
- Section of Cellular Signaling, Department of Physiology and Biophysics, Rush University School of Medicine, Chicago, IL
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90
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Singal A, Mattison LM, Soule CL, Ballard JR, Rudie EN, Cressman ENK, Iaizzo PA. Assessment of Ablative Therapies in Swine: Response of Respiratory Diaphragm to Varying Doses. Ann Biomed Eng 2018; 46:947-959. [PMID: 29594687 DOI: 10.1007/s10439-018-2014-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 03/22/2018] [Indexed: 11/29/2022]
Abstract
Ablation is a common procedure for treating patients with cancer, cardiac arrhythmia, and other conditions, yet it can cause collateral injury to the respiratory diaphragm. Collateral injury can alter the diaphragm's properties and/or lead to respiratory dysfunction. Thus, it is important to understand the diaphragm's physiologic and biomechanical properties in response to ablation therapies, in order to better understand ablative modalities, minimize complications, and maximize the safety and efficacy of ablative procedures. In this study, we analyzed physiologic and biomechanical properties of swine respiratory diaphragm muscle bundles when exposed to 5 ablative modalities. To assess physiologic properties, we performed in vitro tissue bath studies and measured changes in peak force and baseline force. To assess biomechanical properties, we performed uniaxial stress tests, measuring force-displacement responses, stress-strain characteristics, and avulsion forces. After treating the muscle bundles with all 5 ablative modalities, we observed dose-dependent sustained reductions in peak force and transient increases in baseline force-but no consistent dose-dependent biomechanical responses. These data provide novel insights into the effects of various ablative modalities on the respiratory diaphragm, insights that could enable improvements in ablative techniques and therapies.
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Affiliation(s)
- Ashish Singal
- Departments of Surgery and Biomedical Engineering, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA.,Institute for Engineering in Medicine, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA
| | - Lars M Mattison
- Departments of Surgery and Biomedical Engineering, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA.,Institute for Engineering in Medicine, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA
| | - Charles L Soule
- Departments of Surgery and Biomedical Engineering, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA
| | - John R Ballard
- Departments of Surgery and Biomedical Engineering, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA
| | - Eric N Rudie
- Departments of Surgery and Biomedical Engineering, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA
| | - Erik N K Cressman
- Departments of Surgery and Biomedical Engineering, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA
| | - Paul A Iaizzo
- Departments of Surgery and Biomedical Engineering, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA. .,Institute for Engineering in Medicine, University of Minnesota, 420 Delaware St. SE, B172 Mayo, MMC 195, Minneapolis, MN, 55455, USA.
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91
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Gaboardi AJ, Kressler J, Snow TK, Balog EM. Aging impairs regulation of ryanodine receptors from extensor digitorum longus but not soleus muscles. Muscle Nerve 2018; 57:1022-1025. [PMID: 29315676 DOI: 10.1002/mus.26063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 01/03/2018] [Accepted: 01/06/2018] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Because impaired excitation-contraction coupling and reduced sarcoplasmic reticulum (SR) Ca2+ release may contribute to the age-associated decline in skeletal muscle strength, we investigated the effect of aging on regulation of the skeletal muscle isoform of the ryanodine receptor (RyR1) by physiological channel ligands. METHODS [3 H]Ryanodine binding to membranes from 8- and 26-month-old Fischer 344 extensor digitorum longus (EDL) and soleus muscles was used to investigate the effects of age on RyR1 modulation by Ca2+ and calmodulin (CaM). RESULTS Aging reduced maximal Ca2+ -stimulated binding to EDL membranes. In 0.3 μM Ca2+ , age reduced binding and CaM increased binding to EDL membranes. In 300 μM Ca2+ , CaM reduced binding, but the age effect was not significant. Aging did not affect Ca2+ or CaM regulation of soleus RyR1. DISCUSSION In aged fast-twitch muscle, impaired RyR1 Ca2+ regulation may contribute to lower SR Ca2+ release and reduced muscle function. Muscle Nerve 57: 1022-1025, 2018.
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Affiliation(s)
- Angela J Gaboardi
- School of Applied Physiology, Georgia Institute of Technology, 281 Ferst Drive, Atlanta, GA, 30332, USA
| | - Jochen Kressler
- Exercise and Nutritional Sciences Department, School of Health and Human Services, San Diego State University, 5500 Campanile Dr., San Diego, CA 92182, USA
| | - Teresa K Snow
- School of Applied Physiology, Georgia Institute of Technology, 281 Ferst Drive, Atlanta, GA, 30332, USA
| | - Edward M Balog
- School of Applied Physiology, Georgia Institute of Technology, 281 Ferst Drive, Atlanta, GA, 30332, USA
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92
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Chakrabarti R, Ji WK, Stan RV, de Juan Sanz J, Ryan TA, Higgs HN. INF2-mediated actin polymerization at the ER stimulates mitochondrial calcium uptake, inner membrane constriction, and division. J Cell Biol 2018; 217:251-268. [PMID: 29142021 PMCID: PMC5748994 DOI: 10.1083/jcb.201709111] [Citation(s) in RCA: 212] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/13/2017] [Accepted: 10/13/2017] [Indexed: 12/29/2022] Open
Abstract
Mitochondrial division requires division of both the inner and outer mitochondrial membranes (IMM and OMM, respectively). Interaction with endoplasmic reticulum (ER) promotes OMM division by recruitment of the dynamin Drp1, but effects on IMM division are not well characterized. We previously showed that actin polymerization through ER-bound inverted formin 2 (INF2) stimulates Drp1 recruitment in mammalian cells. Here, we show that INF2-mediated actin polymerization stimulates a second mitochondrial response independent of Drp1: a rise in mitochondrial matrix calcium through the mitochondrial calcium uniporter. ER stores supply the increased mitochondrial calcium, and the role of actin is to increase ER-mitochondria contact. Myosin IIA is also required for this mitochondrial calcium increase. Elevated mitochondrial calcium in turn activates IMM constriction in a Drp1-independent manner. IMM constriction requires electron transport chain activity. IMM division precedes OMM division. These results demonstrate that actin polymerization independently stimulates the dynamics of both membranes during mitochondrial division: IMM through increased matrix calcium, and OMM through Drp1 recruitment.
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Affiliation(s)
- Rajarshi Chakrabarti
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Wei-Ke Ji
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Radu V Stan
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | | | - Timothy A Ryan
- Department of Biochemistry, Weill Cornell Medical College, New York, NY
| | - Henry N Higgs
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
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93
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Santulli G, Lewis D, des Georges A, Marks AR, Frank J. Ryanodine Receptor Structure and Function in Health and Disease. Subcell Biochem 2018; 87:329-352. [PMID: 29464565 PMCID: PMC5936639 DOI: 10.1007/978-981-10-7757-9_11] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ryanodine receptors (RyRs) are ubiquitous intracellular calcium (Ca2+) release channels required for the function of many organs including heart and skeletal muscle, synaptic transmission in the brain, pancreatic beta cell function, and vascular tone. In disease, defective function of RyRs due either to stress (hyperadrenergic and/or oxidative overload) or genetic mutations can render the channels leaky to Ca2+ and promote defective disease-causing signals as observed in heat failure, muscular dystrophy, diabetes mellitus, and neurodegerative disease. RyRs are massive structures comprising the largest known ion channel-bearing macromolecular complex and exceeding 3 million Daltons in molecular weight. RyRs mediate the rapid release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR) to stimulate cellular functions through Ca2+-dependent processes. Recent advances in single-particle cryogenic electron microscopy (cryo-EM) have enabled the determination of atomic-level structures for RyR for the first time. These structures have illuminated the mechanisms by which these critical ion channels function and interact with regulatory ligands. In the present chapter we discuss the structure, functional elements, gating and activation mechanisms of RyRs in normal and disease states.
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Affiliation(s)
- Gaetano Santulli
- The Wu Center for Molecular Cardiology, Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, USA
- The Wilf Family Cardiovascular Research Institute and the Einstein-Mount Sinai Diabetes Research Center, Department of Medicine, Albert Einstein College of Medicine - Montefiore University Hospital, New York, NY, USA
| | - Daniel Lewis
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Amedee des Georges
- Advanced Science Research Center at the Graduate Center of the City University of New York, New York, NY, USA
- Department of Chemistry & Biochemistry, City College of New York, New York, NY, USA
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Department of Medicine, Columbia University, New York, NY, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
- Department of Biological Sciences, Columbia University, New York, NY, USA.
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94
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Nicolas WJ, Grison MS, Bayer EM. Shaping intercellular channels of plasmodesmata: the structure-to-function missing link. JOURNAL OF EXPERIMENTAL BOTANY 2017; 69:91-103. [PMID: 28992136 DOI: 10.1093/jxb/erx225] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Plasmodesmata (PD) are a hallmark of the plant kingdom and a cornerstone of plant biology and physiology, forming the conduits for the cell-to-cell transfer of proteins, RNA and various metabolites, including hormones. They connect the cytosols and endomembranes of cells, which allows enhanced cell-to-cell communication and synchronization. Because of their unique position as intercellular gateways, they are at the frontline of plant defence and signalling and constitute the battleground for virus replication and spreading. The membranous organization of PD is remarkable, where a tightly furled strand of endoplasmic reticulum comes into close apposition with the plasma membrane, the two connected by spoke-like elements. The role of these structural features is, to date, still not completely understood. Recent data on PD seem to point in an unexpected direction, establishing a close parallel between PD and membrane contact sites and defining plasmodesmal membranes as microdomains. However, the implications of this new viewpoint are not fully understood. Aided by available phylogenetic data, this review attempts to reassess the function of the different elements comprising the PD and the relevance of membrane lipid composition and biophysics in defining specialized microdomains of PD, critical for their function.
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Affiliation(s)
- William J Nicolas
- Laboratoire de Biogénèse Membranaire, UMR 5200 CNRS, University of Bordeaux, France
| | - Magali S Grison
- Laboratoire de Biogénèse Membranaire, UMR 5200 CNRS, University of Bordeaux, France
| | - Emmanuelle M Bayer
- Laboratoire de Biogénèse Membranaire, UMR 5200 CNRS, University of Bordeaux, France
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95
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Hallas T, Eisen B, Shemer Y, Ben Jehuda R, Mekies LN, Naor S, Schick R, Eliyahu S, Reiter I, Vlodavsky E, Katz YS, Õunap K, Lorber A, Rodenburg R, Mandel H, Gherghiceanu M, Binah O. Investigating the cardiac pathology of SCO2-mediated hypertrophic cardiomyopathy using patients induced pluripotent stem cell-derived cardiomyocytes. J Cell Mol Med 2017; 22:913-925. [PMID: 29193756 PMCID: PMC5783844 DOI: 10.1111/jcmm.13392] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/11/2017] [Indexed: 01/13/2023] Open
Abstract
Mutations in SCO2 are among the most common causes of COX deficiency, resulting in reduced mitochondrial oxidative ATP production capacity, often leading to hypertrophic cardiomyopathy (HCM). To date, none of the recent pertaining reports provide deep understanding of the SCO2 disease pathophysiology. To investigate the cardiac pathology of the disease, we were the first to generate induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iPSC-CMs) from SCO2-mutated patients. For iPSC generation, we reprogrammed skin fibroblasts from two SCO2 patients and healthy controls. The first patient was a compound heterozygote to the common E140K mutation, and the second was homozygote for the less common G193S mutation. iPSC were differentiated into cardiomyocytes through embryoid body (EB) formation. To test the hypothesis that the SCO2 mutation is associated with mitochondrial abnormalities, and intracellular Ca2+ -overload resulting in functional derangements and arrhythmias, we investigated in SCO2-mutated iPSC-CMs (compared to control cardiomyocytes): (i) the ultrastructural changes; (ii) the inotropic responsiveness to β-adrenergic stimulation, increased [Ca2+ ]o and angiotensin-II (AT-II); and (iii) the Beat Rate Variability (BRV) characteristics. In support of the hypothesis, we found in the mutated iPSC-CMs major ultrastructural abnormalities and markedly attenuated response to the inotropic interventions and caffeine, as well as delayed afterdepolarizations (DADs) and increased BRV, suggesting impaired SR Ca2+ handling due to attenuated SERCA activity caused by ATP shortage. Our novel results show that iPSC-CMs are useful for investigating the pathophysiological mechanisms underlying the SCO2 mutation syndrome.
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Affiliation(s)
- Tova Hallas
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Binyamin Eisen
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Yuval Shemer
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Ronen Ben Jehuda
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel.,Department of Biotechnology, Technion, Haifa, Israel
| | - Lucy N Mekies
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Shulamit Naor
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Revital Schick
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Sivan Eliyahu
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Irina Reiter
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Eugene Vlodavsky
- Department of Pathology, Rambam Health Care Campus, Haifa, Israel
| | - Yeshayahu Shai Katz
- Rappaport Faculty of Medicine, Technion, Haifa, Israel.,Department of Anesthesiology, Rambam Health Care Campus, Haifa, Israel
| | - Katrin Õunap
- Department of Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia.,Department of Pediatrics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Avraham Lorber
- Rappaport Faculty of Medicine, Technion, Haifa, Israel.,Department of Pediatric Cardiology, Rambam Health Care Campus, Haifa, Israel
| | - Richard Rodenburg
- Radboud Center for Mitochondrial Disorders, Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hanna Mandel
- Rappaport Faculty of Medicine, Technion, Haifa, Israel.,Metabolic Unit, Department of Pediatrics, Rambam Health Care Campus, Haifa, Israel
| | | | - Ofer Binah
- Department of Physiology, Biophysics and Systems Biology, Technion, Haifa, Israel.,The Rappaport Institute, Technion, Haifa, Israel.,Rappaport Faculty of Medicine, Technion, Haifa, Israel
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96
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Meissner G. The structural basis of ryanodine receptor ion channel function. J Gen Physiol 2017; 149:1065-1089. [PMID: 29122978 PMCID: PMC5715910 DOI: 10.1085/jgp.201711878] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/12/2017] [Indexed: 01/25/2023] Open
Abstract
Large-conductance Ca2+ release channels known as ryanodine receptors (RyRs) mediate the release of Ca2+ from an intracellular membrane compartment, the endo/sarcoplasmic reticulum. There are three mammalian RyR isoforms: RyR1 is present in skeletal muscle; RyR2 is in heart muscle; and RyR3 is expressed at low levels in many tissues including brain, smooth muscle, and slow-twitch skeletal muscle. RyRs form large protein complexes comprising four 560-kD RyR subunits, four ∼12-kD FK506-binding proteins, and various accessory proteins including calmodulin, protein kinases, and protein phosphatases. RyRs share ∼70% sequence identity, with the greatest sequence similarity in the C-terminal region that forms the transmembrane, ion-conducting domain comprising ∼500 amino acids. The remaining ∼4,500 amino acids form the large regulatory cytoplasmic "foot" structure. Experimental evidence for Ca2+, ATP, phosphorylation, and redox-sensitive sites in the cytoplasmic structure have been described. Exogenous effectors include the two Ca2+ releasing agents caffeine and ryanodine. Recent work describing the near atomic structures of mammalian skeletal and cardiac muscle RyRs provides a structural basis for the regulation of the RyRs by their multiple effectors.
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Affiliation(s)
- Gerhard Meissner
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, NC
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97
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Estell EG, Murphy LA, Silverstein AM, Tan AR, Shah RP, Ateshian GA, Hung CT. Fibroblast-like synoviocyte mechanosensitivity to fluid shear is modulated by interleukin-1α. J Biomech 2017; 60:91-99. [PMID: 28716465 PMCID: PMC5788292 DOI: 10.1016/j.jbiomech.2017.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 06/10/2017] [Accepted: 06/13/2017] [Indexed: 11/29/2022]
Abstract
Fibroblast-like synoviocytes (FLS) reside in the synovial membrane of diarthrodial joints and are exposed to a dynamic fluid environment that presents both physical and chemical stimuli. The ability of FLS to sense and respond to these stimuli plays a key role in their normal function, and is implicated in the alterations to function that occur in osteoarthritis (OA). The present work characterizes the response of FLS to fluid flow-induced shear stress via real-time calcium imaging, and tests the hypothesis that this response is modulated by interleukin-1α (IL-1α), a cytokine elevated in OA. FLS demonstrated a robust calcium signaling response to fluid shear that was dose dependent upon stress level and required both external and internal calcium sources. Preconditioning with 10ng/mL IL-1α for 24h heightened this shear stress response by significantly increasing the percent of responding cells and peak magnitude, while significantly decreasing the time for a peak to occur. Intercellular communication via gap junctions was found to account for a portion of the FLS population response in normal conditions, and was significantly increased by IL-1α preconditioning. IL-1α was also found to significantly increase average length and incidence of the primary cilium, an organelle commonly implicated in shear mechanosensing. These findings suggest that the elevated levels of IL-1α found in the OA environment heighten FLS sensitivity to fluid shear by altering both intercellular communication and individual cell sensitivity, which could affect downstream functions and contribute to progression of the disease state.
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Affiliation(s)
- Eben G Estell
- Columbia University, Department of Biomedical Engineering, New York, NY, United States
| | - Lance A Murphy
- Columbia University, Department of Biomedical Engineering, New York, NY, United States
| | - Amy M Silverstein
- Columbia University, Department of Biomedical Engineering, New York, NY, United States
| | - Andrea R Tan
- Columbia University, Department of Biomedical Engineering, New York, NY, United States
| | - Roshan P Shah
- Columbia University, Department of Orthopedic Surgery, New York, NY, United States
| | - Gerard A Ateshian
- Columbia University, Department of Biomedical Engineering, New York, NY, United States
| | - Clark T Hung
- Columbia University, Department of Biomedical Engineering, New York, NY, United States.
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98
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Lukyanenko V, Muriel JM, Bloch RJ. Coupling of excitation to Ca 2+ release is modulated by dysferlin. J Physiol 2017; 595:5191-5207. [PMID: 28568606 DOI: 10.1113/jp274515] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 05/16/2017] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Dysferlin, the protein missing in limb girdle muscular dystrophy 2B and Miyoshi myopathy, concentrates in transverse tubules of skeletal muscle, where it stabilizes voltage-induced Ca2+ transients against loss after osmotic shock injury (OSI). Local expression of dysferlin in dysferlin-null myofibres increases transient amplitude to control levels and protects them from loss after OSI. Inhibitors of ryanodine receptors (RyR1) and L-type Ca2+ channels protect voltage-induced Ca2+ transients from loss; thus both proteins play a role in injury in dysferlin's absence. Effects of Ca2+ -free medium and S107, which inhibits SR Ca2+ leak, suggest the SR as the primary source of Ca2+ responsible for the loss of the Ca2+ transient upon injury. Ca2+ waves were induced by OSI and suppressed by exogenous dysferlin. We conclude that dysferlin prevents injury-induced SR Ca2+ leak. ABSTRACT Dysferlin concentrates in the transverse tubules of skeletal muscle and stabilizes Ca2+ transients when muscle fibres are subjected to osmotic shock injury (OSI). We show here that voltage-induced Ca2+ transients elicited in dysferlin-null A/J myofibres were smaller than control A/WySnJ fibres. Regional expression of Venus-dysferlin chimeras in A/J fibres restored the full amplitude of the Ca2+ transients and protected against OSI. We also show that drugs that target ryanodine receptors (RyR1: dantrolene, tetracaine, S107) and L-type Ca2+ channels (LTCCs: nifedipine, verapamil, diltiazem) prevented the decrease in Ca2+ transients in A/J fibres following OSI. Diltiazem specifically increased transients by ∼20% in uninjured A/J fibres, restoring them to control values. The fact that both RyR1s and LTCCs were involved in OSI-induced damage suggests that damage is mediated by increased Ca2+ leak from the sarcoplasmic reticulum (SR) through the RyR1. Congruent with this, injured A/J fibres produced Ca2+ sparks and Ca2+ waves. S107 (a stabilizer of RyR1-FK506 binding protein coupling that reduces Ca2+ leak) or local expression of Venus-dysferlin prevented OSI-induced Ca2+ waves. Our data suggest that dysferlin modulates SR Ca2+ release in skeletal muscle, and that in its absence OSI causes increased RyR1-mediated Ca2+ leak from the SR into the cytoplasm.
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Affiliation(s)
- Valeriy Lukyanenko
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joaquin M Muriel
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Robert J Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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Contacts between the endoplasmic reticulum and other membranes in neurons. Proc Natl Acad Sci U S A 2017; 114:E4859-E4867. [PMID: 28559323 DOI: 10.1073/pnas.1701078114] [Citation(s) in RCA: 318] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Close appositions between the membrane of the endoplasmic reticulum (ER) and other intracellular membranes have important functions in cell physiology. These include lipid homeostasis, regulation of Ca2+ dynamics, and control of organelle biogenesis and dynamics. Although these membrane contacts have previously been observed in neurons, their distribution and abundance have not been systematically analyzed. Here, we have used focused ion beam-scanning electron microscopy to generate 3D reconstructions of intracellular organelles and their membrane appositions involving the ER (distance ≤30 nm) in different neuronal compartments. ER-plasma membrane (PM) contacts were particularly abundant in cell bodies, with large, flat ER cisternae apposed to the PM, sometimes with a notably narrow lumen (thin ER). Smaller ER-PM contacts occurred throughout dendrites, axons, and in axon terminals. ER contacts with mitochondria were abundant in all compartments, with the ER often forming a network that embraced mitochondria. Small focal contacts were also observed with tubulovesicular structures, likely to be endosomes, and with sparse multivesicular bodies and lysosomes found in our reconstructions. Our study provides an anatomical reference for interpreting information about interorganelle communication in neurons emerging from functional and biochemical studies.
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100
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Chang CL, Chen YJ, Liou J. ER-plasma membrane junctions: Why and how do we study them? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1494-1506. [PMID: 28554772 DOI: 10.1016/j.bbamcr.2017.05.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/09/2017] [Accepted: 05/17/2017] [Indexed: 12/17/2022]
Abstract
Endoplasmic reticulum (ER)-plasma membrane (PM) junctions are membrane microdomains important for communication between the ER and the PM. ER-PM junctions were first reported in muscle cells in 1957, but mostly ignored in non-excitable cells due to their scarcity and lack of functional significance. In 2005, the discovery of stromal interaction molecule 1 (STIM1) mediating a universal Ca2+ feedback mechanism at ER-PM junctions in mammalian cells led to a resurgence of research interests toward ER-PM junctions. In the past decade, several major advancements have been made in this emerging topic in cell biology, including the generation of tools for labeling ER-PM junctions and the unraveling of mechanisms underlying regulation and functions of ER-PM junctions. This review summarizes early studies, recently developed tools, and current advances in the characterization and understanding of ER-PM junctions. This article is part of a Special Issue entitled: Membrane Contact Sites edited by Christian Ungermann and Benoit Kornmann.
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Affiliation(s)
- Chi-Lun Chang
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yu-Ju Chen
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen Liou
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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