1
|
Franzini-Armstrong C. An updated view of the structural basis for dihydropyridine receptors-ryanodine receptors direct molecular interaction in skeletal muscle. Eur J Transl Myol 2024; 34:12476. [PMID: 38516838 PMCID: PMC11017163 DOI: 10.4081/ejtm.2024.12476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 03/23/2024] Open
Abstract
This presentation reviews images of electron micrographs from various skeletal muscles identifying a consistent association of diydropyridine receptors (DHPR) tetrads with alternate ryanodine receptors. Imaging of the junctional gap in triads from various sources provide direct evidence for the association of four diydropyridine receptors (DHPRs), clustered into tetrads, with alternate ryanodine receptors (RyRs). It is not clear whether firing of all four components of a tetrad is necessary to fully activate the opening of the RyR channel.
Collapse
Affiliation(s)
- Clara Franzini-Armstrong
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA.
| |
Collapse
|
2
|
Scardigli M, Pásek M, Santini L, Palandri C, Conti E, Crocini C, Campione M, Loew LM, de Vries AAF, Pijnappels DA, Pavone FS, Poggesi C, Cerbai E, Coppini R, Kohl P, Ferrantini C, Sacconi L. Optogenetic confirmation of transverse-tubular membrane excitability in intact cardiac myocytes. J Physiol 2024; 602:791-808. [PMID: 38348881 DOI: 10.1113/jp285202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 01/17/2024] [Indexed: 03/09/2024] Open
Abstract
T-tubules (TT) form a complex network of sarcolemmal membrane invaginations, essential for well-co-ordinated excitation-contraction coupling (ECC) and thus homogeneous mechanical activation of cardiomyocytes. ECC is initiated by rapid depolarization of the sarcolemmal membrane. Whether TT membrane depolarization is active (local generation of action potentials; AP) or passive (following depolarization of the outer cell surface sarcolemma; SS) has not been experimentally validated in cardiomyocytes. Based on the assessment of ion flux pathways needed for AP generation, we hypothesize that TT are excitable. We therefore explored TT excitability experimentally, using an all-optical approach to stimulate and record trans-membrane potential changes in TT that were structurally disconnected, and hence electrically insulated, from the SS membrane by transient osmotic shock. Our results establish that cardiomyocyte TT can generate AP. These AP show electrical features that differ substantially from those observed in SS, consistent with differences in the density of ion channels and transporters in the two different membrane domains. We propose that TT-generated AP represent a safety mechanism for TT AP propagation and ECC, which may be particularly relevant in pathophysiological settings where morpho-functional changes reduce the electrical connectivity between SS and TT membranes. KEY POINTS: Cardiomyocytes are characterized by a complex network of membrane invaginations (the T-tubular system) that propagate action potentials to the core of the cell, causing uniform excitation-contraction coupling across the cell. In the present study, we investigated whether the T-tubular system is able to generate action potentials autonomously, rather than following depolarization of the outer cell surface sarcolemma. For this purpose, we developed a fully optical platform to probe and manipulate the electrical dynamics of subcellular membrane domains. Our findings demonstrate that T-tubules are intrinsically excitable, revealing distinct characteristics of self-generated T-tubular action potentials. This active electrical capability would protect cells from voltage drops potentially occurring within the T-tubular network.
Collapse
Affiliation(s)
- Marina Scardigli
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Michal Pásek
- Institute of Thermomechanics, Czech Academy of Science, Prague, Czech Republic
- Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Lorenzo Santini
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Chiara Palandri
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Emilia Conti
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
- Neuroscience Institute, National Research Council, Pisa, Italy
| | - Claudia Crocini
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Max Rubner Center for Cardiovascular Metabolic Renal Research (MRC), Deutsches Herzzentrum der Charité (DHZC), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Marina Campione
- Institute of Neuroscience (IN-CNR) and Department of Biomedical Science, University of Padua, Padua, Italy
| | - Leslie M Loew
- Center for Cell Analysis and Modeling, University of Connecticut, Farmington, CT, USA
| | - Antoine A F de Vries
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Daniël A Pijnappels
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Francesco S Pavone
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Elisabetta Cerbai
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
| | - Raffaele Coppini
- Department of Neurology, Psychology, Drug Sciences and Child Health, University of Florence, Florence, Italy
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy - LENS, Sesto Fiorentino, Italy
- Institute for Experimental Cardiovascular Medicine, University Heart Center and Medical Faculty, University of Freiburg, Freiburg, Germany
- Institute of Clinical Physiology, National Research Council (IFC-CNR), Florence, Italy
| |
Collapse
|
3
|
Emerson JI, Ariel P, Shi W, Conlon FL. Sex Differences in Mouse Cardiac Electrophysiology Revealed by Simultaneous Imaging of Excitation-Contraction Coupling. J Cardiovasc Dev Dis 2023; 10:479. [PMID: 38132647 PMCID: PMC10743987 DOI: 10.3390/jcdd10120479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Males and females differ in the basic anatomy and physiology of the heart. Sex differences are evident in cardiac repolarization in humans; women have longer corrected QT and JT intervals. However, the molecular mechanisms that lead to these differences are incompletely understood. Here, we present that, like in humans, sex differences in QT and JT intervals exist in mouse models; female mice had longer corrected QT and JT intervals compared with age-matched males. To further understand the molecular underpinning of these sex differences, we developed a novel technology using fluorescent confocal microscopy that allows the simultaneous visualization of action potential, Ca2+ transients, and contractions in isolated cardiomyocytes at a high temporal resolution. From this approach, we uncovered that females at baseline have increased action potential duration, decreased Ca2+ release and reuptake rates, and decreased contraction and relaxation velocities compared with males. Additionally, males had a shorter overall time from action potential onset to peak contraction. In aggregate, our studies uncovered male and female differences in excitation-contraction coupling that account for differences observed in the EKG. Overall, a better understanding of sex differences in electrophysiology is essential for equitably treating cardiac disease.
Collapse
Affiliation(s)
- James I. Emerson
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Pablo Ariel
- Microscopy Services Laboratory, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Wei Shi
- Department of Biology and Genetics, McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Frank L. Conlon
- Department of Biology and Genetics, McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| |
Collapse
|
4
|
Lu S, Liang Y, Yang S, Fu M, Shan X, Zhang C, Chen H, Zhao P, Lu R. Stachydrine Hydrochloride Regulates the NOX2-ROS-Signaling Axis in Pressure-Overload-Induced Heart Failure. Int J Mol Sci 2023; 24:14369. [PMID: 37762672 PMCID: PMC10531983 DOI: 10.3390/ijms241814369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/15/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
Our previous studies revealed the protection of stachydrine hydrochloride (STA) against cardiopathological remodeling. One of the underlying mechanisms involves the calcium/calmodulin-dependent protein kinase Ⅱ (CaMKII). However, the way STA influences CaMKII needs to be further investigated. The nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2)-coupled reactive oxygen species (ROS) overproduction putatively induces the oxidative activation of CaMKII, resulting in the occurrence of pathological cardiac remodeling and dysfunction in experimental models of mice. Thus, in this study, we assessed the role of the NOX2-ROS signal axis in STA cardioprotection. The transverse aortic constriction (TAC)-induced heart failure model of mice, the phenylephrine-induced hypertrophic model of neonatal rat primary cardiomyocytes, and the H2O2-induced oxidative stress models of adult mouse primary cardiomyocytes and H9c2 cells were employed. The echocardiography and histological staining were applied to assess the cardiac effect of STA (6 mg/kg/d or 12 mg/kg/d), which was given by gavage. NOX2, ROS, and excitation-contraction (EC) coupling were detected by Western blotting, immunofluorescence, and calcium transient-contraction synchronous recordings. ROS and ROS-dependent cardiac fibrosis were alleviated in STA-treated TAC mice, demonstrating improved left ventricular ejection fraction and hypertrophy. In the heart failure model of mice and the hypertrophic model of cardiomyocytes, STA depressed NOX2 protein expression and activation, as shown by inhibited translocation of its phosphorylation, p67phox and p47phox, from the cytoplasm to the cell membrane. Furthermore, in cardiomyocytes under oxidative stress, STA suppressed NOX2-related cytosolic Ca2+ overload, enhanced cell contractility, and decreased Ca2+-dependent regulatory protein expression, including CaMKⅡ and Ryanodine receptor calcium release channels. Cardioprotection of STA against pressure overload-induced pathological cardiac remodeling correlates with the NOX2-coupled ROS signaling cascade.
Collapse
Affiliation(s)
- Shuang Lu
- School of Traditional Chinese Medicine, SHUTCM, Shanghai 201203, China; (S.L.); (Y.L.); (S.Y.); (M.F.); (H.C.)
| | - Yueyang Liang
- School of Traditional Chinese Medicine, SHUTCM, Shanghai 201203, China; (S.L.); (Y.L.); (S.Y.); (M.F.); (H.C.)
| | - Songru Yang
- School of Traditional Chinese Medicine, SHUTCM, Shanghai 201203, China; (S.L.); (Y.L.); (S.Y.); (M.F.); (H.C.)
| | - Mengwei Fu
- School of Traditional Chinese Medicine, SHUTCM, Shanghai 201203, China; (S.L.); (Y.L.); (S.Y.); (M.F.); (H.C.)
| | - Xiaoli Shan
- Public Experiment Platform, School of Traditional Chinese Medicine, SHUTCM, Shanghai 201203, China;
| | - Chen Zhang
- Department of Pathology, School of Intergrative Medicine, SHUTCM, Shanghai 201203, China;
| | - Huihua Chen
- School of Traditional Chinese Medicine, SHUTCM, Shanghai 201203, China; (S.L.); (Y.L.); (S.Y.); (M.F.); (H.C.)
| | - Pei Zhao
- Public Experiment Platform, School of Traditional Chinese Medicine, SHUTCM, Shanghai 201203, China;
| | - Rong Lu
- School of Traditional Chinese Medicine, SHUTCM, Shanghai 201203, China; (S.L.); (Y.L.); (S.Y.); (M.F.); (H.C.)
| |
Collapse
|
5
|
Tokuda N, Watanabe D, Naito A, Yamauchi N, Ashida Y, Cheng AJ, Yamada T. Intrinsic contractile dysfunction due to impaired sarcoplasmic reticulum Ca 2+ release in compensatory hypertrophied muscle fibers following synergist ablation. Am J Physiol Cell Physiol 2023; 325:C599-C612. [PMID: 37486068 DOI: 10.1152/ajpcell.00127.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/12/2023] [Accepted: 07/12/2023] [Indexed: 07/25/2023]
Abstract
Synergist ablation (SA) is an experimental procedure for the induction of hypertrophy. However, SA causes a decrease in specific force (i.e., force per cross-sectional area), likely due to excessive muscle use. Here, we investigated the mechanisms behind the SA-induced intrinsic contractile dysfunction, especially focusing on the excitation-contraction (EC) coupling. Male Wistar rats had unilateral surgical ablation of gastrocnemius and soleus muscles to induce compensatory hypertrophy in the plantaris muscles. Two weeks after SA, plantaris muscle was dissected from each animal and used for later analyses. SA significantly increased the mean fiber cross-sectional area (+18%). On the other hand, the ratio of depolarization-induced force to the maximum Ca2+-activated specific force, an indicator of sarcoplasmic reticulum (SR) Ca2+ release, was markedly reduced in mechanically skinned fibers from the SA group (-51%). These functional defects were accompanied by an extensive fragmentation of the SR Ca2+ release channel, the ryanodine receptor 1 (RyR1), and a decrease in the amount of other triad proteins (i.e., DHPR, STAC3, and junctophilin1). SA treatment also caused activation of calpain-1 and increased the amount of NADPH oxidase 2, endoplasmic reticulum (ER) stress proteins (i.e., Grp78, Grp94, PDI, and Ero1), and lipid peroxidation [i.e., 4-hydroxynonenal (4-HNE)] in SA-treated muscles. Our findings show that SA causes skeletal muscle weakness due to impaired EC coupling. This is likely to be induced by Ca2+-dependent degradation of triad proteins, which may result from Ca2+ leak from fragmented RyR1 triggered by increased oxidative stress.NEW & NOTEWORTHY Synergist ablation (SA) has widely been used to understand the mechanisms behind skeletal muscle hypertrophy. However, compensatory hypertrophied muscles display intrinsic contractile dysfunction, i.e., a hallmark of overuse. Here, we demonstrate that SA-induced compensatory hypertrophy is accompanied by muscle weakness due to impaired sarcoplasmic reticulum Ca2+ release. This dysfunction may be caused by the degradation of triad proteins due to the reciprocal amplification of reactive oxygen species and Ca2+ signaling at the junctional space microdomain.
Collapse
Affiliation(s)
- Nao Tokuda
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Daiki Watanabe
- Graduate School of Sport and Health Sciences, Osaka University of Health and Sport Sciences, Osaka, Japan
| | - Azuma Naito
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Nao Yamauchi
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Yuki Ashida
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
- The Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Arthur J Cheng
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada
| | - Takashi Yamada
- Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| |
Collapse
|
6
|
Laasmaa M, Branovets J, Stolova J, Shen X, Rätsepso T, Balodis MJ, Grahv C, Hendrikson E, Louch WE, Birkedal R, Vendelin M. Cardiomyocytes from female compared to male mice have larger ryanodine receptor clusters and higher calcium spark frequency. J Physiol 2023; 601:4033-4052. [PMID: 37561554 DOI: 10.1113/jp284515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 07/07/2023] [Indexed: 08/11/2023] Open
Abstract
Sex differences in cardiac physiology are receiving increased attention as it has become clear that men and women have different aetiologies of cardiac disease and require different treatments. There are experimental data suggesting that male cardiomyocytes exhibit larger Ca2+ transients due to larger Ca2+ sparks and a higher excitation-contraction coupling gain; in addition, they exhibit a larger response to adrenergic stimulation with isoprenaline (ISO). Here, we studied whether there are sex differences relating to structural organization of the transverse tubular network and ryanodine receptors (RyRs). Surprisingly, we found that female cardiomyocytes exhibited a higher spark frequency in a range of spark magnitudes. While overall RyR expression and phosphorylation were the same, female cardiomyocytes had larger but fewer RyR clusters. The density of transverse t-tubules was the same, but male cardiomyocytes had more longitudinal t-tubules. The Ca2+ transients were similar in male and female cardiomyocytes under control conditions and in the presence of ISO. The synchrony of the Ca2+ transients was similar between sexes as well. Overall, our data suggest subtle sex differences in the Ca2+ influx and efflux pathways and their response to ISO, but these differences are balanced, resulting in similar Ca2+ transients in field-stimulated male and female cardiomyocytes. The higher spark frequency in female cardiomyocytes is related to the organization of RyRs into larger, but fewer clusters. KEY POINTS: During a heartbeat, the force of contraction depends on the amplitude of the calcium transient, which in turn depends on the amount of calcium released as calcium sparks through ryanodine receptors in the sarcoplasmic reticulum. Previous studies suggest that cardiomyocytes from male compared to female mice exhibit larger calcium sparks, larger sarcoplasmic reticulum calcium release and greater response to adrenergic stimulation triggering a fight-or-flight response. In contrast, we show that cardiomyocytes from female mice have a higher spark frequency during adrenergic stimulation and similar spark morphology. The higher spark frequency is related to the organization of ryanodine receptors into fewer, but larger clusters in female compared to male mouse cardiomyocytes. Despite subtle sex differences in cardiomyocyte structure and calcium fluxes, the differences are balanced, leading to similar calcium transients in cardiomyocytes from male and female mice.
Collapse
Affiliation(s)
- Martin Laasmaa
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
- Institute for Experimental Medical Research, University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Jelena Branovets
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Jekaterina Stolova
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Xin Shen
- Institute for Experimental Medical Research, University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Triinu Rätsepso
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Mihkel Jaan Balodis
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Cärolin Grahv
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Eliise Hendrikson
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - William Edward Louch
- Institute for Experimental Medical Research, University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Rikke Birkedal
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Marko Vendelin
- Laboratory of Systems Biology, Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| |
Collapse
|
7
|
Szedlak P, Steele D, Hopkins P. Cardiac muscle physiology. BJA Educ 2023; 23:350-357. [PMID: 37600215 PMCID: PMC10435365 DOI: 10.1016/j.bjae.2023.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2023] [Indexed: 08/22/2023] Open
Affiliation(s)
- P. Szedlak
- Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | | | - P.M. Hopkins
- Leeds Teaching Hospitals NHS Trust, Leeds, UK
- University of Leeds, Leeds, UK
| |
Collapse
|
8
|
Salameh S, Ogueri V, Posnack NG. Adapting to a new environment: postnatal maturation of the human cardiomyocyte. J Physiol 2023; 601:2593-2619. [PMID: 37031380 PMCID: PMC10775138 DOI: 10.1113/jp283792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/16/2023] [Indexed: 04/10/2023] Open
Abstract
The postnatal mammalian heart undergoes remarkable developmental changes, which are stimulated by the transition from the intrauterine to extrauterine environment. With birth, increased oxygen levels promote metabolic, structural and biophysical maturation of cardiomyocytes, resulting in mature muscle with increased efficiency, contractility and electrical conduction. In this Topical Review article, we highlight key studies that inform our current understanding of human cardiomyocyte maturation. Collectively, these studies suggest that human atrial and ventricular myocytes evolve quickly within the first year but might not reach a fully mature adult phenotype until nearly the first decade of life. However, it is important to note that fetal, neonatal and paediatric cardiac physiology studies are hindered by a number of limitations, including the scarcity of human tissue, small sample size and a heavy reliance on diseased tissue samples, often without age-matched healthy controls. Future developmental studies are warranted to expand our understanding of normal cardiac physiology/pathophysiology and inform age-appropriate treatment strategies for cardiac disease.
Collapse
Affiliation(s)
- Shatha Salameh
- Department of Pharmacology & Physiology, George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC, USA
| | - Vanessa Ogueri
- Children’s National Heart Institute, Children’s National Hospital, Washington, DC, USA
| | - Nikki Gillum Posnack
- Department of Pharmacology & Physiology, George Washington University, Washington, DC, USA
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC, USA
- Children’s National Heart Institute, Children’s National Hospital, Washington, DC, USA
- Department of Pediatrics, George Washington University, Washington, DC, USA
| |
Collapse
|
9
|
Kanaporis G, Martinez‐Hernandez E, Blatter LA. Calcium- and voltage-driven atrial alternans: Insight from [Ca] i and V m asynchrony. Physiol Rep 2023; 11:e15703. [PMID: 37226365 PMCID: PMC10209431 DOI: 10.14814/phy2.15703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 04/21/2023] [Accepted: 04/23/2023] [Indexed: 05/26/2023] Open
Abstract
Cardiac alternans is defined as beat-to-beat alternations in contraction strength, action potential duration (APD), and Ca transient (CaT) amplitude. Cardiac excitation-contraction coupling relies on the activity of two bidirectionally coupled excitable systems, membrane voltage (Vm ) and Ca release. Alternans has been classified as Vm - or Ca-driven, depending whether a disturbance of Vm or [Ca]i regulation drives the alternans. We determined the primary driver of pacing induced alternans in rabbit atrial myocytes, using combined patch clamp and fluorescence [Ca]i and Vm measurements. APD and CaT alternans are typically synchronized; however, uncoupling between APD and CaT regulation can lead to CaT alternans in the absence of APD alternans, and APD alternans can fail to precipitate CaT alternans, suggesting a considerable degree of independence of CaT and APD alternans. Using alternans AP voltage clamp protocols with extra APs showed that most frequently the pre-existing CaT alternans pattern prevailed after the extra-beat, indicating that alternans is Ca-driven. In electrically coupled cell pairs, dyssynchrony of APD and CaT alternans points to autonomous regulation of CaT alternans. Thus, with three novel experimental protocols, we collected evidence for Ca-driven alternans; however, the intimately intertwined regulation of Vm and [Ca]i precludes entirely independent development of CaT and APD alternans.
Collapse
Affiliation(s)
- G. Kanaporis
- Department of Physiology & BiophysicsRush University Medical CenterChicagoIllinoisUSA
| | - E. Martinez‐Hernandez
- Department of Physiology & BiophysicsRush University Medical CenterChicagoIllinoisUSA
| | - L. A. Blatter
- Department of Physiology & BiophysicsRush University Medical CenterChicagoIllinoisUSA
| |
Collapse
|
10
|
Kiessling M, Djalinac N, Voglhuber J, Ljubojevic-Holzer S. Nuclear Calcium in Cardiac (Patho)Physiology: Small Compartment, Big Impact. Biomedicines 2023; 11:biomedicines11030960. [PMID: 36979939 PMCID: PMC10046765 DOI: 10.3390/biomedicines11030960] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
The nucleus of a cardiomyocyte has been increasingly recognized as a morphologically distinct and partially independent calcium (Ca2+) signaling microdomain, with its own Ca2+-regulatory mechanisms and important effects on cardiac gene expression. In this review, we (1) provide a comprehensive overview of the current state of research on the dynamics and regulation of nuclear Ca2+ signaling in cardiomyocytes, (2) address the role of nuclear Ca2+ in the development and progression of cardiac pathologies, such as heart failure and atrial fibrillation, and (3) discuss novel aspects of experimental methods to investigate nuclear Ca2+ handling and its downstream effects in the heart. Finally, we highlight current challenges and limitations and recommend future directions for addressing key open questions.
Collapse
Affiliation(s)
- Mara Kiessling
- Department of Cardiology, Medical University of Graz, 8036 Graz, Austria
| | - Nataša Djalinac
- Department of Biology, University of Padua, 35122 Padova, Italy
| | - Julia Voglhuber
- Department of Cardiology, Medical University of Graz, 8036 Graz, Austria
- BioTechMed Graz, 8010 Graz, Austria
| | - Senka Ljubojevic-Holzer
- Department of Cardiology, Medical University of Graz, 8036 Graz, Austria
- BioTechMed Graz, 8010 Graz, Austria
- Gottfried Schatz Research Center, Division of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria
| |
Collapse
|
11
|
Ferro LA, Fernandes SLA, Kalinin AL, Monteiro DA. Effects of exposure to sediment-associated fipronil on cardiac function of Neotropical armored catfish Hypostomus regani. J Environ Sci Health A Tox Hazard Subst Environ Eng 2023; 58:236-245. [PMID: 36803268 DOI: 10.1080/10934529.2023.2182582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Fipronil is widely used as a broad-spectrum insecticide in agriculture, urban environments, and veterinary medicine. Fipronil can enter aquatic ecosystems and spread to sediment and organic matter, representing a risk to non-target species. This study aimed to evaluate the effects of short-term (96 h) exposure to a low and realistic concentration of sediment-associated fipronil (4.2 µg.kg-1 of Regent® 800 WG) on myocardial contractility of armored catfish Hypostomus regain, a benthic fish species. Fipronil exposure induced increased inotropism and acceleration of contractile kinetics, although no alterations in the relative ventricular mass were observed. This better cardiac function was associated with an elevated expression and/or function of the Na+/Ca2+ exchanger and its marked contribution to contraction and relaxation, probably due to a stress-induced adrenergic stimulation. Ventricle strips of exposed fish also exhibited a faster relaxation and a higher cardiac pumping capacity, indicating that armored catfish were able to perform cardiac adjustments to face the exposure. However, a high energetic cost to maintain an increased cardiac performance can make fish more susceptible to other stressors, impairing developmental processes and/or survival. These findings highlight the need for regulations of emerging contaminants, such as fipronil, to ensure adequate protection of the aquatic system.
Collapse
Affiliation(s)
- Lucas Abreu Ferro
- Joint Graduate Program in Physiological Sciences, Federal University of São Carlos (UFSCar), São Paulo State University (UNESP), São Carlos, Araraquara, Brazil
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Suzana Luisa Alves Fernandes
- Joint Graduate Program in Physiological Sciences, Federal University of São Carlos (UFSCar), São Paulo State University (UNESP), São Carlos, Araraquara, Brazil
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Ana Lúcia Kalinin
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Diana Amaral Monteiro
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| |
Collapse
|
12
|
Drouin PJ, Liu T, Lew LA, McGarity-Shipley E, Tschakovsky ME. The 'normal' adjustment of oxygen delivery to small muscle mass exercise is not optimized for muscle contractile function. J Physiol 2023; 601:783-799. [PMID: 36644910 DOI: 10.1113/jp283933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 01/04/2023] [Indexed: 01/17/2023] Open
Abstract
Oxygen delivery is viewed as tightly coupled to demand in exercise below critical power because increasing oxygen delivery does not increase V O 2 ${V_{{O_2}}}$ . However, whether the 'normal' adjustment of oxygen delivery to small muscle mass exercise in the heavy intensity domain is optimal for excitation-contraction coupling is currently unknown. In 20 participants (10 female), a remote skeletal muscle (i.e. tibialis anterior) metaboreflex was (Hyperperfusion condition) or was not (Control condition) activated for 4 min during both force of contraction (experimental model 1) and muscle activation-targeted (experimental model 2) rhythmic forearm handgrip exercise. Analysis was completed on the combined data from both experimental models. After 30 s of remote skeletal muscle metaboreflex activation, mean arterial blood pressure, forearm blood flow and muscle oxygenation were increased and remained increased until metaboreflex discontinuation. While oxygen delivery was elevated, the muscle activation to force of contraction ratio was improved. Upon metaboreflex discontinuation, forearm oxygen delivery and the muscle activation and force of contraction ratio rapidly (within 30 s) returned to control levels. These findings demonstrate that (a) the metaboreflex was effective at increasing forearm muscle oxygen delivery and oxygenation, (b) the muscle activation to force of contraction ratio was improved with increased oxygen delivery, and (c) in the heavy exercise intensity domain, the normal matching of oxygen delivery to metabolic demand is not optimal for muscle excitation-contraction coupling. These results suggest that the nature of vasoregulation in exercising muscle is such that it does not support optimal perfusion for excitation-contraction coupling. KEY POINTS: Oxygen delivery is viewed as tightly coupled to demand in exercise below critical power because increasing oxygen delivery does not increase the rate of oxygen uptake. Whether the 'normal' adjustment of oxygen delivery in small muscle mass exercise below critical power is optimal for excitation-contraction coupling is not known. Here we show in humans that increasing oxygen delivery above 'normal' improves excitation-contraction coupling. These results suggest that, in the heavy exercise intensity domain, the 'normal' matching of oxygen delivery to metabolic demand is not optimal for muscle excitation-contraction coupling. Therefore, the nature of vasoregulation in exercising muscle is such that it does not support optimal perfusion for excitation-contraction coupling.
Collapse
Affiliation(s)
- Patrick J Drouin
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Taylor Liu
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Lindsay A Lew
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Ellen McGarity-Shipley
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Michael E Tschakovsky
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| |
Collapse
|
13
|
Cros C, Douard M, Chaigne S, Pasqualin C, Bru-Mercier G, Recalde A, Pascarel-Auclerc C, Hof T, Haïssaguerre M, Hocini M, Jaïs P, Bernus O, Brette F. Regional Differences in Ca(2+) Signaling and Transverse-Tubules across Left Atrium from Adult Sheep. Int J Mol Sci 2023; 24. [PMID: 36768669 DOI: 10.3390/ijms24032347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/27/2023] Open
Abstract
Cardiac excitation-contraction coupling can be different between regions of the heart. Little is known at the atria level, specifically in different regions of the left atrium. This is important given the role of cardiac myocytes from the pulmonary vein sleeves, which are responsible for ectopic activity during atrial fibrillation. In this study, we present a new method to isolate atrial cardiac myocytes from four different regions of the left atrium of a large animal model, sheep, highly relevant to humans. Using collagenase/protease we obtained calcium-tolerant atrial cardiac myocytes from the epicardium, endocardium, free wall and pulmonary vein regions. Calcium transients were slower (time to peak and time to decay) in free wall and pulmonary vein myocytes compared to the epicardium and endocardium. This is associated with lower t-tubule density. Overall, these results suggest regional differences in calcium transient and t-tubule density across left atria, which may play a major role in the genesis of atrial fibrillation.
Collapse
|
14
|
Mosqueira M, Brinkmeier H, Jaimovich E. Editorial: Calcium homeostasis in skeletal muscle function, plasticity and disease, Volume II. Front Physiol 2023; 14:1130073. [PMID: 36744029 PMCID: PMC9896099 DOI: 10.3389/fphys.2023.1130073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/09/2023] [Indexed: 01/21/2023] Open
Affiliation(s)
- Matias Mosqueira
- Institute of Physiology and Pathophysiology, Heidelberg University Hospital, Heidelberg, Germany,*Correspondence: Matias Mosqueira,
| | - Heinrich Brinkmeier
- Institute of Pathophysiology University Medicine Greifswald, Greifswald, Germany
| | - Enrique Jaimovich
- Center for Exercise, Metabolism, and Cancer Studies, Faculty of Medicine, University of Chile, Santiago, Chile
| |
Collapse
|
15
|
Kanaporis G, Blatter LA. Activation of small conductance Ca 2+ -activated K + channels suppresses Ca 2+ transient and action potential alternans in ventricular myocytes. J Physiol 2023; 601:51-67. [PMID: 36426548 PMCID: PMC9878619 DOI: 10.1113/jp283870] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022] Open
Abstract
At the cellular level, cardiac alternans is observed as beat-to-beat alternations in contraction strength, action potential (AP) morphology and Ca2+ transient (CaT) amplitude, and is a risk factor for cardiac arrhythmia. The (patho)physiological roles of small conductance Ca2+ -activated K+ (SK) channels in ventricles are poorly understood. We tested the hypothesis that in single rabbit ventricular myocytes pharmacological modulation of SK channels plays a causative role for the development of pacing-induced CaT and AP duration (APD) alternans. SK channel blockers (apamin, UCL1684) had only a minor effect on AP repolarization. However, SK channel activation by NS309 resulted in significant APD shortening, demonstrating that functional SK channels are well expressed in ventricular myocytes. The effects of NS309 were prevented or reversed by apamin and UCL1684, indicating that NS309 acted on SK channels. SK channel activation abolished or reduced the degree of pacing-induced CaT and APD alternans. Inhibition of KV 7.1 (with HMR1556) and KV 11.1 (with E4031) channels was used to mimic conditions of long QT syndromes type-1 and type-2, respectively. Both HMR1556 and E4031 enhanced CaT alternans that was prevented by SK channel activation. In AP voltage-clamped cells the SK channel activator had no effect on CaT alternans, confirming that suppression of CaT alternans was caused by APD shortening. APD shortening contributed to protection from alternans by lowering sarcoplasmic reticulum Ca2+ content and curtailing Ca2+ release. The data suggest that SK activation could be a potential intervention to avert development of alternans with important ramifications for arrhythmia prevention and therapy for patients with long QT syndrome. KEY POINTS: At the cellular level, cardiac alternans is observed as beat-to-beat alternations in contraction strength, action potential (AP) morphology and intracellular Ca2+ release amplitude, and is a risk factor for cardiac arrhythmia. The (patho)physiological roles of small conductance Ca2+ -activated K+ (SK) channels in ventricles are poorly understood. We investigated whether pharmacological modulation of SK channels affects the development of cardiac alternans in normal ventricular cells and in cells with drug-induced long QT syndrome (LQTS). While SK channel blockers have only a minor effect on AP morphology, their activation leads to AP shortening and abolishes or reduces the degree of pacing-induced Ca2+ and AP alternans. AP shortening contributed to protection against alternans by lowering sarcoplasmic reticulum Ca2+ content and curtailing Ca2+ release. The data suggest SK activation as a potential intervention to avert the development of alternans with important ramifications for arrhythmia prevention for patients with LQTS.
Collapse
Affiliation(s)
- Giedrius Kanaporis
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, Illinois, USA
| | - Lothar A Blatter
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, Illinois, USA
| |
Collapse
|
16
|
Holmes M, Hurley ME, Sheard TMD, Benson AP, Jayasinghe I, Colman MA. Increased SERCA2a sub-cellular heterogeneity in right-ventricular heart failure inhibits excitation-contraction coupling and modulates arrhythmogenic dynamics. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210317. [PMID: 36189801 PMCID: PMC9527927 DOI: 10.1098/rstb.2021.0317] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/21/2021] [Indexed: 12/14/2022] Open
Abstract
The intracellular calcium handling system of cardiomyocytes is responsible for controlling excitation-contraction coupling (ECC) and has been linked to pro-arrhythmogenic cellular phenomena in conditions such as heart failure (HF). SERCA2a, responsible for intracellular uptake, is a primary regulator of calcium homeostasis, and remodelling of its function has been proposed as a causal factor underlying cellular and tissue dysfunction in disease. Whereas adaptations to the global (i.e. whole-cell) expression of SERCA2a have been previously investigated in the context of multiple diseases, the role of its spatial profile in the sub-cellular volume has yet to be elucidated. We present an approach to characterize the sub-cellular heterogeneity of SERCA2a and apply this approach to quantify adaptations to the length-scale of heterogeneity (the distance over which expression is correlated) associated with right-ventricular (RV)-HF. These characterizations informed simulations to predict the functional implications of this heterogeneity, and its remodelling in disease, on ECC, the dynamics of calcium-transient alternans and the emergence of spontaneous triggered activity. Image analysis reveals that RV-HF is associated with an increase in length-scale and its inter-cellular variability; simulations predict that this increase in length-scale can reduce ECC and critically modulate the vulnerability to both alternans and triggered activity. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
Collapse
Affiliation(s)
- M. Holmes
- Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - M. E. Hurley
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - T. M. D. Sheard
- School of Biosciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - A. P. Benson
- Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, UK
| | - I. Jayasinghe
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
- School of Biosciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - M. A. Colman
- Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| |
Collapse
|
17
|
Vigh‐Larsen JF, Ørtenblad N, Emil Andersen O, Thorsteinsson H, Kristiansen TH, Bilde S, Mikkelsen MS, Nielsen J, Mohr M, Overgaard K. Fibre type- and localisation-specific muscle glycogen utilisation during repeated high-intensity intermittent exercise. J Physiol 2022; 600:4713-4730. [PMID: 36030498 PMCID: PMC9825866 DOI: 10.1113/jp283225] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/24/2022] [Indexed: 01/11/2023] Open
Abstract
Glycogen particles are situated in key areas of the muscle cell in the vicinity of the main energy-consumption sites and may be utilised heterogeneously dependent on the nature of the metabolic demands. The present study aimed to investigate the time course of fibre type-specific utilisation of muscle glycogen in three distinct subcellular fractions (intermyofibrillar, IMF; intramyofibrillar, Intra; and subsarcolemmal, SS) during repeated high-intensity intermittent exercise. Eighteen moderately to well-trained male participants performed three periods of 10 × 45 s cycling at ∼105% watt max (EX1-EX3) coupled with 5 × 6 s maximal sprints at baseline and after each period. Muscle biopsies were sampled at baseline and after EX1 and EX3. A higher glycogen breakdown rate in type 2 compared to type 1 fibres was found during EX1 for the Intra (-72 vs. -45%) and IMF (-59 vs. -35%) glycogen fractions (P < 0.001) but with no differences for SS glycogen (-52 vs. -40%). In contrast, no fibre type differences were observed during EX2-EX3, where the utilisation of Intra and IMF glycogen in type 2 fibres was reduced, resulting in depletion of all three subcellular fractions to very low levels post-exercise within both fibre types. Importantly, large heterogeneity in single-fibre glycogen utilisation was present with an early depletion of especially Intra glycogen in individual type 2 fibres. In conclusion, there is a clear fibre type- and localisation-specific glycogen utilisation during high-intensity intermittent exercise, which varies with time course of exercise and is characterised by exacerbated pool-specific glycogen depletion at the single-fibre level. KEY POINTS: Muscle glycogen is the major fuel during high-intensity exercise and is stored in distinct subcellular areas of the muscle cell in close vicinity to the main energy consumption sites. In the present study quantitative electron microscopy imaging was used to investigate the utilisation pattern of three distinct subcellular muscle glycogen fractions during repeated high-intensity intermittent exercise. It is shown that the utilisation differs dependent on fibre type, subcellular localisation and time course of exercise and with large single-fibre heterogeneity. These findings expand on our understanding of subcellular muscle glycogen metabolism during exercise and may help us explain how reductions in muscle glycogen can attenuate muscle function even at only moderately lowered whole-muscle glycogen concentrations.
Collapse
Affiliation(s)
- Jeppe F. Vigh‐Larsen
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark
| | - Ole Emil Andersen
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark,Steno Diabetes Center AarhusAarhus University HospitalAarhusDenmark
| | - Hallur Thorsteinsson
- Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark
| | - Thea H. Kristiansen
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| | - Stine Bilde
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| | - Mads S. Mikkelsen
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| | - Joachim Nielsen
- Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark
| | - Magni Mohr
- Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark,Centre of Health ScienceUniversity of the Faroe IslandsTórshavnFaroe Islands
| | - Kristian Overgaard
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| |
Collapse
|
18
|
Lubel E, Grandi-Sgambato B, Barsakcioglu DY, Ibanez J, Tang MX, Farina D. Kinematics of individual muscle units in natural contractions measured in vivo using ultrafast ultrasound. J Neural Eng 2022; 19. [PMID: 36001952 DOI: 10.1088/1741-2552/ac8c6c] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/24/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The study of human neuromechanical control at the motor unit (MU) level has predominantly focussed on electrical activity and force generation, whilst the link between these, i.e., the muscle deformation, has not been widely studied. To address this gap, we analysed the kinematics of muscle units in natural contractions. APPROACH We combined high-density surface electromyography (HDsEMG) and ultrafast ultrasound (US) recordings, at 1000 frames per second, from the tibialis anterior muscle to measure the motion of the muscular tissue caused by individual MU contractions. The MU discharge times were identified online by decomposition of the HDsEMG and provided as biofeedback to 12 subjects who were instructed to keep the MU active at the minimum discharge rate (9.8 ± 4.7 pulses per second; force less than 10% of the maximum). The series of discharge times were used to identify the velocity maps associated with 51 single muscle unit movements with high spatio-temporal precision, by a novel processing method on the concurrently recorded US images. From the individual MU velocity maps, we estimated the region of movement, the duration of the motion, the contraction time, and the excitation-contraction (E-C) coupling delay. MAIN RESULTS Individual muscle unit motions could be reliably identified from the velocity maps in 10 out of 12 subjects. The duration of the motion, total contraction time, and E-C coupling were 17.9 ± 5.3 ms, 56.6 ± 8.4 ms, and 3.8 ± 3.0 ms (n = 390 across 10 participants). The experimental measures also provided the first evidence of muscle unit twisting during voluntary contractions and MU territories with distinct split regions. SIGNIFICANCE The proposed method allows for the study of kinematics of individual MU twitches during natural contractions. The described measurements and characterisations open new avenues for the study of neuromechanics in healthy and pathological conditions.
Collapse
Affiliation(s)
- Emma Lubel
- Department of Bioengineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Bruno Grandi-Sgambato
- Department of Bioengineering, Imperial College London, Exhibition road, London, SW7 2AZ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Deren Y Barsakcioglu
- Department of Bioengineering, Imperial College London, Exhibition road, London, SW7 2AZ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Jaime Ibanez
- Bioengineering Group, Imperial College London, Engineering, London, SW7 2AZ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, Department of Bioeng, London, -- Select One --, SW7 2AZ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Dario Farina
- Department of Bioengineering, Imperial College London, Exhibition road, London, SW7 2AZ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| |
Collapse
|
19
|
Vattemi GNA, Rossi D, Galli L, Catallo MR, Pancheri E, Marchetto G, Cisterna B, Malatesta M, Pierantozzi E, Tonin P, Sorrentino V. Ryanodine receptor 1 (RYR1) mutations in two patients with tubular aggregate myopathy. Eur J Neurosci 2022; 56:4214-4223. [PMID: 35666680 PMCID: PMC9539902 DOI: 10.1111/ejn.15728] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 11/30/2022]
Abstract
Two likely causative mutations in the RYR1 gene were identified in two patients with myopathy with tubular aggregates, but no evidence of cores or core‐like pathology on muscle biopsy. These patients were clinically evaluated and underwent routine laboratory investigations, electrophysiologic tests, muscle biopsy and muscle magnetic resonance imaging (MRI). They reported stiffness of the muscles following sustained activity or cold exposure and had serum creatine kinase elevation. The identified RYR1 mutations (p.Thr2206Met or p.Gly2434Arg, in patient 1 and patient 2, respectively) were previously identified in individuals with malignant hyperthermia susceptibility and are reported as causative according to the European Malignant Hyperthermia Group rules. To our knowledge, these data represent the first identification of causative mutations in the RYR1 gene in patients with tubular aggregate myopathy and extend the spectrum of histological alterations caused by mutation in the RYR1 gene.
Collapse
Affiliation(s)
- Gaetano Nicola Alfio Vattemi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Daniela Rossi
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, Siena, Italy.,Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Lucia Galli
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Maria Rosaria Catallo
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, Siena, Italy
| | - Elia Pancheri
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Giulia Marchetto
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Barbara Cisterna
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy
| | - Manuela Malatesta
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, Siena, Italy
| | - Paola Tonin
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, Siena, Italy.,Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| |
Collapse
|
20
|
Pioner JM, Vitale G, Gentile F, Scellini B, Piroddi N, Cerbai E, Olivotto I, Tardiff J, Coppini R, Tesi C, Poggesi C, Ferrantini C. Genotype-Driven Pathogenesis of Atrial Fibrillation in Hypertrophic Cardiomyopathy: The Case of Different TNNT2 Mutations. Front Physiol 2022; 13:864547. [PMID: 35514357 PMCID: PMC9062294 DOI: 10.3389/fphys.2022.864547] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/28/2022] [Indexed: 11/25/2022] Open
Abstract
Atrial dilation and atrial fibrillation (AF) are common in Hypertrophic CardioMyopathy (HCM) patients and associated with a worsening of prognosis. The pathogenesis of atrial myopathy in HCM remains poorly investigated and no specific association with genotype has been identified. By re-analysis of our cohort of thin-filament HCM patients (Coppini et al. 2014) AF was identified in 10% of patients with sporadic mutations in the cardiac Troponin T gene (TNNT2), while AF occurrence was much higher (25-75%) in patients carrying specific "hot-spot" TNNT2 mutations. To determine the molecular basis of arrhythmia occurrence, two HCM mouse models expressing human TNNT2 variants (a "hot-spot" one, R92Q, and a "sporadic" one, E163R) were selected according to the different pathophysiological pathways previously demonstrated in ventricular tissue. Echocardiography studies showed a significant left atrial dilation in both models, but more pronounced in the R92Q. In E163R atrial trabeculae, in line with what previously observed in ventricular preparations, the energy cost of tension generation was markedly increased. However, no changes of twitch amplitude and kinetics were observed, and there was no atrial arrhythmic propensity. R92Q atrial trabeculae, instead, displayed normal ATP consumption but markedly increased myofilament calcium sensitivity, as previously observed in ventricular preparations. This was associated with reduced inotropic reserve and slower kinetics of twitch contractions and, importantly, with an increased occurrence of spontaneous beats and triggered contractions that represent an intrinsic arrhythmogenic mechanism promoting AF. The association of specific TNNT2 mutations with AF occurrence depends on the mutation-driven pathomechanism (i.e., increased atrial myofilament calcium sensitivity rather than increased myofilament tension cost) and may influence the individual response to treatment.
Collapse
Affiliation(s)
| | - Giulia Vitale
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Francesca Gentile
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | | | - Iacopo Olivotto
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Jil Tardiff
- Department of Medicine and Biomedical Engineering, University of Arizona, Tucson, AZ, United States
| | | | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| |
Collapse
|
21
|
Abstract
Each heartbeat is initiated by the action potential, an electrical signal that depolarizes the plasma membrane and activates a cycle of calcium influx via voltage-gated calcium channels, calcium release via ryanodine receptors, and calcium reuptake and efflux via calcium-ATPase pumps and sodium-calcium exchangers. Agonists of the sympathetic nervous system bind to adrenergic receptors in cardiomyocytes, which, via cascading signal transduction pathways and protein kinase A (PKA), increase the heart rate (chronotropy), the strength of myocardial contraction (inotropy), and the rate of myocardial relaxation (lusitropy). These effects correlate with increased intracellular concentration of calcium, which is required for the augmentation of cardiomyocyte contraction. Despite extensive investigations, the molecular mechanisms underlying sympathetic nervous system regulation of calcium influx in cardiomyocytes have remained elusive over the last 40 years. Recent studies have uncovered the mechanisms underlying this fundamental biologic process, namely that PKA phosphorylates a calcium channel inhibitor, Rad, thereby releasing inhibition and increasing calcium influx. Here, we describe an updated model for how signals from adrenergic agonists are transduced to stimulate calcium influx and contractility in the heart.
Collapse
Affiliation(s)
- Arianne Papa
- Department of Physiology and Cellular Biophysics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Jared Kushner
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA;
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA;
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| |
Collapse
|
22
|
Lang D, Medvedev RY, Ratajczyk L, Zheng J, Yuan X, Lim E, Han OY, Valdivia HH, Glukhov AV. Region-specific distribution of transversal-axial tubule system organization underlies heterogeneity of calcium dynamics in the right atrium. Am J Physiol Heart Circ Physiol 2022; 322:H269-H284. [PMID: 34951544 PMCID: PMC8782648 DOI: 10.1152/ajpheart.00381.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The atrial myocardium demonstrates the highly heterogeneous organization of the transversal-axial tubule system (TATS), although its anatomical distribution and region-specific impact on Ca2+ dynamics remain unknown. Here, we developed a novel method for high-resolution confocal imaging of TATS in intact live mouse atrial myocardium and applied a custom-developed MATLAB-based computational algorithm for the automated analysis of TATS integrity. We observed a twofold higher (P < 0.01) TATS density in the right atrial appendage (RAA) than in the intercaval regions (ICR, the anatomical region between the superior vena cava and atrioventricular junction and between the crista terminalis and interatrial septum). Whereas RAA predominantly consisted of well-tubulated myocytes, ICR showed partially tubulated/untubulated cells. Similar TATS distribution was also observed in healthy human atrial myocardium sections. In both mouse atrial preparations and isolated mouse atrial myocytes, we observed a strong anatomical correlation between TATS distribution and Ca2+ transient synchronization and rise-up time. This region-specific difference in Ca2+ transient morphology disappeared after formamide-induced detubulation. ICR myocytes showed a prolonged action potential duration at 80% of repolarization as well as a significantly lower expression of RyR2 and Cav1.2 proteins but similar levels of NCX1 and Cav1.3 compared with RAA tissue. Our findings provide a detailed characterization of the region-specific distribution of TATS in mouse and human atrial myocardium, highlighting the structural foundation for anatomical heterogeneity of Ca2+ dynamics and contractility in the atria. These results could indicate different roles of TATS in Ca2+ signaling at distinct anatomical regions of the atria and provide mechanistic insight into pathological atrial remodeling.NEW & NOTEWORTHY Mouse and human atrial myocardium demonstrate high variability in the organization of the transversal-axial tubule system (TATS), with more organized TATS expressed in the right atrial appendage. TATS distribution governs anatomical heterogeneity of Ca2+ dynamics and thus could contribute to integral atrial contractility, mechanics, and arrhythmogenicity.
Collapse
Affiliation(s)
- Di Lang
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Roman Y Medvedev
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Lucas Ratajczyk
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Jingjing Zheng
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Xiaoyu Yuan
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Evi Lim
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Owen Y Han
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Hector H Valdivia
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Alexey V Glukhov
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| |
Collapse
|
23
|
Nayak AR, Samsó M. Ca 2+ inactivation of the mammalian ryanodine receptor type 1 in a lipidic environment revealed by cryo-EM. eLife 2022; 11:75568. [PMID: 35257661 PMCID: PMC8947763 DOI: 10.7554/elife.75568] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/28/2022] [Indexed: 01/07/2023] Open
Abstract
Activation of the intracellular Ca2+ channel ryanodine receptor (RyR) triggers a cytosolic Ca2+ surge, while elevated cytosolic Ca2+ inhibits the channel in a negative feedback mechanism. Cryogenic electron microscopy of rabbit RyR1 embedded in nanodiscs under partially inactivating Ca2+ conditions revealed an open and a closed-inactivated conformation. Ca2+ binding to the high-affinity site engages the central and C-terminal domains into a block, which pries the S6 four-helix bundle open. Further rotation of this block pushes S6 toward the central axis, closing (inactivating) the channel. Main characteristics of the Ca2+-inactivated conformation are downward conformation of the cytoplasmic assembly and tightly knit subunit interface contributed by a fully occupied Ca2+ activation site, two inter-subunit resolved lipids, and two salt bridges between the EF hand domain and the S2-S3 loop validated by disease-causing mutations. The structural insight illustrates the prior Ca2+ activation prerequisite for Ca2+ inactivation and provides for a seamless transition from inactivated to closed conformations.
Collapse
Affiliation(s)
- Ashok R Nayak
- Department of Physiology and Biophysics, Virginia Commonwealth UniversityRichmondUnited States
| | - Montserrat Samsó
- Department of Physiology and Biophysics, Virginia Commonwealth UniversityRichmondUnited States
| |
Collapse
|
24
|
Monteiro O, Bhaskar A, Ng AKM, Murdoch CE, Baptista-Hon DT. Computer-based virtual laboratory simulations: LabHEART cardiac physiology practical. Adv Physiol Educ 2021; 45:856-868. [PMID: 34473584 DOI: 10.1152/advan.00094.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Practical demonstration of cardiomyocyte function requires substantial preparation, a source of freshly isolated animal hearts, and specialized equipment. Even where such resources are available, it is not conducive for demonstration to any more than a few students at a time. These approaches are also not consistent with the 3R principle (replacement, reduction, and refinement) of ethical use of animals. We present an implementation of the LabHEART software, developed by Donald Bers and Jose Puglisi, for medical students. Prior to the activity, students had lectures covering the physiological and pharmacological aspects of cardiac excitation-contraction (EC) coupling. We used this problem-based activity to help students consolidate their knowledge and to allow a hands-on approach to explore the key features of EC coupling. Students simulate and measure action potentials, intracellular calcium changes, and cardiomyocyte contraction. They also apply drugs that target ion channels (e.g., nifedipine or tetrodotoxin) or sympathetic input (using isoproterenol) and explore changes to EC coupling. Furthermore, by modifying the biophysical parameters of key ion channels involved in the electrical activity of the heart, students also explore the effect of channelopathies such as long QT syndromes. We describe approaches to implement this activity in a flipped classroom format, with recorded lecture materials provided ahead of the practical to facilitate active learning. We also describe our experiences implementing this activity online. The content and difficulty of the activity can be altered to suit individual courses and is also amenable to promote peer-driven learning.
Collapse
Affiliation(s)
- Olivia Monteiro
- Department of Biomedical Sciences, Faculty of Medicine, Macau University of Science and Technology, Taipa, Macau S.A.R., China
| | - Anand Bhaskar
- Department of Biomedical Sciences, Faculty of Medicine, Macau University of Science and Technology, Taipa, Macau S.A.R., China
| | - Anna K M Ng
- Department of Biomedical Sciences, Faculty of Medicine, Macau University of Science and Technology, Taipa, Macau S.A.R., China
| | - Colin E Murdoch
- Systems Medicine, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Daniel T Baptista-Hon
- Department of Biomedical Sciences, Faculty of Medicine, Macau University of Science and Technology, Taipa, Macau S.A.R., China
- Systems Medicine, School of Medicine, University of Dundee, Dundee, United Kingdom
| |
Collapse
|
25
|
Bertero E, Nickel A, Kohlhaas M, Hohl M, Sequeira V, Brune C, Schwemmlein J, Abeßer M, Schuh K, Kutschka I, Carlein C, Münker K, Atighetchi S, Müller A, Kazakov A, Kappl R, von der Malsburg K, van der Laan M, Schiuma AF, Böhm M, Laufs U, Hoth M, Rehling P, Kuhn M, Dudek J, von der Malsburg A, Prates Roma L, Maack C. Loss of Mitochondrial Ca 2+ Uniporter Limits Inotropic Reserve and Provides Trigger and Substrate for Arrhythmias in Barth Syndrome Cardiomyopathy. Circulation 2021; 144:1694-1713. [PMID: 34648376 DOI: 10.1161/circulationaha.121.053755] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Barth syndrome (BTHS) is caused by mutations of the gene encoding tafazzin, which catalyzes maturation of mitochondrial cardiolipin and often manifests with systolic dysfunction during early infancy. Beyond the first months of life, BTHS cardiomyopathy typically transitions to a phenotype of diastolic dysfunction with preserved ejection fraction, blunted contractile reserve during exercise, and arrhythmic vulnerability. Previous studies traced BTHS cardiomyopathy to mitochondrial formation of reactive oxygen species (ROS). Because mitochondrial function and ROS formation are regulated by excitation-contraction coupling, integrated analysis of mechano-energetic coupling is required to delineate the pathomechanisms of BTHS cardiomyopathy. METHODS We analyzed cardiac function and structure in a mouse model with global knockdown of tafazzin (Taz-KD) compared with wild-type littermates. Respiratory chain assembly and function, ROS emission, and Ca2+ uptake were determined in isolated mitochondria. Excitation-contraction coupling was integrated with mitochondrial redox state, ROS, and Ca2+ uptake in isolated, unloaded or preloaded cardiac myocytes, and cardiac hemodynamics analyzed in vivo. RESULTS Taz-KD mice develop heart failure with preserved ejection fraction (>50%) and age-dependent progression of diastolic dysfunction in the absence of fibrosis. Increased myofilament Ca2+ affinity and slowed cross-bridge cycling caused diastolic dysfunction, in part, compensated by accelerated diastolic Ca2+ decay through preactivated sarcoplasmic reticulum Ca2+-ATPase. Taz deficiency provoked heart-specific loss of mitochondrial Ca2+ uniporter protein that prevented Ca2+-induced activation of the Krebs cycle during β-adrenergic stimulation, oxidizing pyridine nucleotides and triggering arrhythmias in cardiac myocytes. In vivo, Taz-KD mice displayed prolonged QRS duration as a substrate for arrhythmias, and a lack of inotropic response to β-adrenergic stimulation. Cellular arrhythmias and QRS prolongation, but not the defective inotropic reserve, were restored by inhibiting Ca2+ export through the mitochondrial Na+/Ca2+ exchanger. All alterations occurred in the absence of excess mitochondrial ROS in vitro or in vivo. CONCLUSIONS Downregulation of mitochondrial Ca2+ uniporter, increased myofilament Ca2+ affinity, and preactivated sarcoplasmic reticulum Ca2+-ATPase provoke mechano-energetic uncoupling that explains diastolic dysfunction and the lack of inotropic reserve in BTHS cardiomyopathy. Furthermore, defective mitochondrial Ca2+ uptake provides a trigger and a substrate for ventricular arrhythmias. These insights can guide the ongoing search for a cure of this orphaned disease.
Collapse
Affiliation(s)
- Edoardo Bertero
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Now with Department of Internal Medicine and Specialties (Di.M.I.), University of Genoa, Italy (E.B.)
| | - Alexander Nickel
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Michael Kohlhaas
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Mathias Hohl
- Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Vasco Sequeira
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Carolin Brune
- Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Julia Schwemmlein
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Marco Abeßer
- Institute of Physiology, University of Würzburg, Germany (M.A., K.S., M. Kuhn)
| | - Kai Schuh
- Institute of Physiology, University of Würzburg, Germany (M.A., K.S., M. Kuhn)
| | - Ilona Kutschka
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Christopher Carlein
- Department for Biophysics, ZHMB, CIPMM (C.C., R.K., M. Hoth, L.P.R.), Saarland University, Homburg/Saar, Germany
| | - Kai Münker
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Sarah Atighetchi
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Andreas Müller
- Clinic for Radiology (A.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Andrey Kazakov
- Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Reinhard Kappl
- Department for Biophysics, ZHMB, CIPMM (C.C., R.K., M. Hoth, L.P.R.), Saarland University, Homburg/Saar, Germany
| | - Karina von der Malsburg
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Faculty of Medicine (K.v.d.M., M.v.d.L., A.v.d.M.), Saarland University, Homburg/Saar, Germany
| | - Martin van der Laan
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Faculty of Medicine (K.v.d.M., M.v.d.L., A.v.d.M.), Saarland University, Homburg/Saar, Germany
| | - Anna-Florentine Schiuma
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Michael Böhm
- Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Ulrich Laufs
- Now with Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Germany (U.L.)
| | - Markus Hoth
- Department for Biophysics, ZHMB, CIPMM (C.C., R.K., M. Hoth, L.P.R.), Saarland University, Homburg/Saar, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, Georg-August University, Göttingen, Germany (P.R., J.D.).,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (P.R.).,Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany (P.R.)
| | - Michaela Kuhn
- Institute of Physiology, University of Würzburg, Germany (M.A., K.S., M. Kuhn)
| | - Jan Dudek
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Department of Cellular Biochemistry, Georg-August University, Göttingen, Germany (P.R., J.D.)
| | - Alexander von der Malsburg
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Faculty of Medicine (K.v.d.M., M.v.d.L., A.v.d.M.), Saarland University, Homburg/Saar, Germany
| | - Leticia Prates Roma
- Department for Biophysics, ZHMB, CIPMM (C.C., R.K., M. Hoth, L.P.R.), Saarland University, Homburg/Saar, Germany
| | - Christoph Maack
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany.,Department for Internal Medicine 1, University Clinic Würzburg, Germany (C.M.)
| |
Collapse
|
26
|
Santini L, Coppini R, Cerbai E. Ion Channel Impairment and Myofilament Ca 2+ Sensitization: Two Parallel Mechanisms Underlying Arrhythmogenesis in Hypertrophic Cardiomyopathy. Cells 2021; 10:2789. [PMID: 34685769 DOI: 10.3390/cells10102789] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 11/17/2022] Open
Abstract
Life-threatening ventricular arrhythmias are the main clinical burden in patients with hypertrophic cardiomyopathy (HCM), and frequently occur in young patients with mild structural disease. While massive hypertrophy, fibrosis and microvascular ischemia are the main mechanisms underlying sustained reentry-based ventricular arrhythmias in advanced HCM, cardiomyocyte-based functional arrhythmogenic mechanisms are likely prevalent at earlier stages of the disease. In this review, we will describe studies conducted in human surgical samples from HCM patients, transgenic animal models and human cultured cell lines derived from induced pluripotent stem cells. Current pieces of evidence concur to attribute the increased risk of ventricular arrhythmias in early HCM to different cellular mechanisms. The increase of late sodium current and L-type calcium current is an early observation in HCM, which follows post-translation channel modifications and increases the occurrence of early and delayed afterdepolarizations. Increased myofilament Ca2+ sensitivity, commonly observed in HCM, may promote afterdepolarizations and reentry arrhythmias with direct mechanisms. Decrease of K+-currents due to transcriptional regulation occurs in the advanced disease and contributes to reducing the repolarization-reserve and increasing the early afterdepolarizations (EADs). The presented evidence supports the idea that patients with early-stage HCM should be considered and managed as subjects with an acquired channelopathy rather than with a structural cardiac disease.
Collapse
|
27
|
Clos P, Mater A, Laroche D, Lepers R. Concentric versus eccentric cycling at equal power output or effort perception: Neuromuscular alterations and muscle pain. Scand J Med Sci Sports 2021; 32:45-59. [PMID: 34533875 DOI: 10.1111/sms.14053] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/16/2021] [Accepted: 09/14/2021] [Indexed: 12/24/2022]
Abstract
This study aimed to compare neuromuscular alterations and perceptions of effort and muscle pain induced by concentric and eccentric cycling performed at the same power output or effort perception. Fifteen participants completed three 30-min sessions: one in concentric at 60% peak power output (CON) and two in eccentric, at the same power output (ECCPOWER ) or same perceived effort (ECCEFFORT ). Muscle pain, perception of effort, oxygen uptake as well as rectus femoris and vastus lateralis electromyographic activities were collected when pedaling. The knee extensors maximal voluntary contraction (MVC) torque, the torque evoked by double stimulations at 100 Hz and 10 Hz (Dt100; Dt10), and the voluntary activation level (VAL) were evaluated before and after exercise. Power output was higher in ECCEFFORT than CON (89.1 ± 23.3% peak power). Muscle pain and effort perception were greater in CON than ECCPOWER (p < 0.03) while muscle pain was similar in CON and ECCEFFORT (p > 0.43). MVC torque, Dt100, and VAL dropped in all conditions (p < 0.04). MVC torque (p < 0.001) and the Dt10/ Dt100 ratio declined further in ECCEFFORT (p < 0.001). Eccentric cycling perceived as difficult as concentric cycling caused similar muscle pain but more MVC torque decrease. A given power output induced lower perceptions of pain and effort in eccentric than in concentric yet similar MVC torque decline. While neural impairments were similar in all conditions, eccentric cycling seemed to alter excitation-contraction coupling. Clinicians should thus be cautious when setting eccentric cycling intensity based on effort perception.
Collapse
Affiliation(s)
- Pierre Clos
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Adrien Mater
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Davy Laroche
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Romuald Lepers
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| |
Collapse
|
28
|
Kampfer AJ, Balog EM. Electrical polarity-dependent gating and a unique subconductance of RyR2 induced by S-adenosyl methionine via the ATP binding site. J Biochem 2021; 170:739-752. [PMID: 34523682 DOI: 10.1093/jb/mvab093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 08/30/2021] [Indexed: 11/14/2022] Open
Abstract
S-Adenosyl-l-methionine (SAM) was used to probe the functional effects exerted via the RyR2 adenine nucleotide binding site. Single channel experiments revealed that SAM applied to the cytoplasmic face of RyR2 had complex voltage dependent effects on channel gating and conductance. At positive transmembrane holding potentials, SAM caused a striking reduction in channel openings and a reduced channel conductance. In contrast, at negative potentials SAM promoted a clearly resolved subconductance state. At membrane potentials between -75 and -25 mV the open probability of the subconductance state was independent of voltage. ATP, but not the non-adenosine based RyR activator 4-chloro-m-cresol interfered with the effects of SAM at both negative and positive potentials. This suggests that ATP and SAM interact with a common binding site. Molecular docking showed SAM bound to the adenine nucleotide-binding site and formed a hydrogen bond to Glu4886 in the C-terminal end of the S6 alpha helix. In this configuration SAM may alter the conformation of the RyR2 ion conduction pathway. This work provides novel insight into potential functional outcomes of ligand binding to the RyR adenine nucleotide binding site.
Collapse
Affiliation(s)
- Angela J Kampfer
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Edward M Balog
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
| |
Collapse
|
29
|
Belevych AE, Bogdanov V, Terentyev DA, Gyorke S. Acute Detubulation of Ventricular Myocytes Amplifies the Inhibitory Effect of Cholinergic Agonist on Intracellular Ca 2+ Transients. Front Physiol 2021; 12:725798. [PMID: 34512394 PMCID: PMC8427700 DOI: 10.3389/fphys.2021.725798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/02/2021] [Indexed: 11/29/2022] Open
Abstract
Muscarinic receptors expressed in cardiac myocytes play a critical role in the regulation of heart function by the parasympathetic nervous system. How the structural organization of cardiac myocytes affects the regulation of Ca2+ handling by muscarinic receptors is not well-defined. Using confocal Ca2+ imaging, patch-clamp techniques, and immunocytochemistry, the relationship between t-tubule density and cholinergic regulation of intracellular Ca2+ in normal murine ventricular myocytes and myocytes with acute disruption of the t-tubule system caused by formamide treatment was studied. The inhibitory effect of muscarinic receptor agonist carbachol (CCh, 10 μM) on the amplitude of Ca2+ transients, evoked by field-stimulation in the presence of 100 nM isoproterenol (Iso), a β-adrenergic agonist, was directly proportional to the level of myocyte detubulation. The timing of the maximal rate of fluorescence increase of fluo-4, a Ca2+-sensitive dye, was used to classify image pixels into the regions functionally coupled or uncoupled to the sarcolemmal Ca2+ influx (ICa). CCh decreased the fraction of coupled regions and suppressed Ca2+ propagation from sarcolemma inside the cell. Formamide treatment reduced ICa density and decreased sarcoplasmic reticulum (SR) Ca2+ content. CCh did not change SR Ca2+ content in Iso-stimulated control and formamide-treated myocytes. CCh inhibited peak ICa recorded in the presence of Iso by ∼20% in both the control and detubulated myocytes. Reducing ICa amplitude up to 40% by changing the voltage step levels from 0 to –25 mV decreased Ca2+ transients in formamide-treated but not in control myocytes in the presence of Iso. CCh inhibited CaMKII activity, whereas CaMKII inhibition with KN93 mimicked the effect of CCh on Ca2+ transients in formamide-treated myocytes. It was concluded that the downregulation of t-tubules coupled with the diminished efficiency of excitation–contraction coupling, increases the sensitivity of Ca2+ release and propagation to muscarinic receptor-mediated inhibition of both ICa and CaMKII activity.
Collapse
Affiliation(s)
- Andriy E Belevych
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, United States.,Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Vladimir Bogdanov
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, United States.,Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Dmitry A Terentyev
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, United States.,Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Sandor Gyorke
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, United States.,Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| |
Collapse
|
30
|
Körner A, Mosqueira M, Hecker M, Ullrich ND. Substrate Stiffness Influences Structural and Functional Remodeling in Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Front Physiol 2021; 12:710619. [PMID: 34489730 PMCID: PMC8416903 DOI: 10.3389/fphys.2021.710619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 07/26/2021] [Indexed: 01/01/2023] Open
Abstract
Novel treatment strategies for cardiac tissue regeneration are heading for the use of engineered cardiac tissue made from induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Despite the proven cardiogenic phenotype of these cells, a significant lack of structural and functional properties of mature myocytes prevents safe integration into the diseased heart. To date, maturation processes of cardiomyocytes remain largely unknown but may comprise biophysical cues from the immediate cell environment. Mechanosensing is one critical ability of cells to react to environmental changes. Accordingly, the surrounding substrate stiffness, comprised of extracellular matrix (ECM), cells, and growth surface, critically influences the myocyte's physiology, as known from deleterious remodeling processes in fibrotic hearts. Conversely, the mechanical properties during culture of iPSC-CMs may impact on their structural and functional maturation. Here, we tested the hypothesis that the environmental stiffness influences structural and functional properties of iPSC-CMs and investigated the effect of different substrate stiffnesses on cell contractility, excitation-contraction (EC) coupling, and intercellular coupling. Culture surfaces with defined stiffnesses ranging from rigid glass with 25GPa to PDMS of physiological softness were coated with ECM proteins and seeded with murine iPSC-CMs. Using confocal imaging, cardiac protein expression was assessed. Ca2+ handling and contractile properties were analyzed on different substrate stiffnesses. Intercellular coupling via gap junctions was investigated by fluorescence recovery after photobleaching (FRAP). Our data revealed greater organization of L-type Ca2+ channels and ryanodine receptors and increased EC-coupling gain, demonstrating structural and functional maturation in cells grown on soft surfaces. In addition, increased shortening and altered contraction dynamics revealed increased myofilament Ca2+ sensitivity in phase-plane loops. Moreover, connexin 43 expression was significantly increased in iPSC-CMs grown on soft surfaces leading to improved intercellular coupling. Taken together, our results demonstrate that soft surfaces with stiffnesses in the physiological range improve the expression pattern and interaction of cardiac proteins relevant for EC-coupling. In parallel, soft substrates influence contractile properties and improve intercellular coupling in iPSC-CMs. We conclude that the mechanical stiffness of the cell environment plays an important role in driving iPSC-CMs toward further maturation by inducing adaptive responses.
Collapse
Affiliation(s)
- Arlene Körner
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg-Mannheim, Heidelberg, Germany
| | - Matias Mosqueira
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Markus Hecker
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg-Mannheim, Heidelberg, Germany
| | - Nina D Ullrich
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg-Mannheim, Heidelberg, Germany
| |
Collapse
|
31
|
Leermakers PA, Skov M, Riisager A, Nielsen OB, Pedersen TH. Alterations in fast-twitch muscle membrane conductance regulation do not explain decreased muscle function of SOD1 G93A rats. Muscle Nerve 2021; 64:755-764. [PMID: 34486134 DOI: 10.1002/mus.27413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 08/29/2021] [Accepted: 08/31/2021] [Indexed: 11/06/2022]
Abstract
INTRODUCTION/AIMS Both neuromuscular junction (NMJ) dysfunction and altered electrophysiological properties of muscle fibers have been reported in amyotrophic lateral sclerosis (ALS) patients. ALS-related preclinical studies typically use rodent SOD1G93A overexpression models, but translation to the human disease has been challenged. The present work explored NMJ function and cellular electrophysiological properties of muscles fibers in SOD1G93A overexpression rats. METHODS Longitudinal studies of compound muscle action potentials (CMAPs) were performed in SOD1G93A rats. Cellular studies were performed to evaluate electrophysiological properties of muscle fibers, including the resting membrane conductance (Gm ) and its regulation during prolonged action potential (AP) firing. RESULTS SOD1G93A rats showed a substantial loss of gastrocnemius CMAP amplitude (35.8 mV, P < .001) and a minor increase in CMAP decrement (8.5%, P = .002) at 25 weeks. In addition, SOD1G93A EDL muscle fibers showed a lower baseline Gm (wild-type, 1325 μS/cm2 ; SOD1G93A , 1137 μS/cm2 ; P < .001) and minor alterations in Gm regulation during repeated firing of APs as compared with wild-type rats. DISCUSSION The current data suggest that loss of CMAP amplitude is largely explained by defects in either lower motor neuron or skeletal muscle with only minor indications of a role for neuromuscular transmission defects in SOD1G93A rats. Electrophysiological properties of muscle fibers were not markedly affected, and an elevated Gm , as has been reported in motor neuron disease (MND) patients, was not replicated in SOD1G93A muscles. Collectively, the neuromuscular pathology of SOD1G93A rats appears to differ from that of ALS/MND patients with respect to neuromuscular transmission defects and electrophysiological properties of muscle fibers.
Collapse
Affiliation(s)
| | - Martin Skov
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Anders Riisager
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ole B Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | |
Collapse
|
32
|
Singlár Z, Szentesi P, Fodor J, Angyal Á, Csernoch L, Sztretye M. Assessing the Potential of Nutraceuticals as Geroprotectors on Muscle Performance and Cognition in Aging Mice. Antioxidants (Basel) 2021; 10:1415. [PMID: 34573047 DOI: 10.3390/antiox10091415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/26/2021] [Accepted: 08/31/2021] [Indexed: 11/17/2022] Open
Abstract
Aging and frailty are associated with a decline in muscle force generation, which is a direct consequence of reduced muscle quantity and quality. Among the leading contributors to aging is the generation of reactive oxygen species, the byproducts of terminal oxidation. Their negative effects can be moderated via antioxidant supplementation. Krill oil and astaxanthin (AX) are nutraceuticals with a variety of health promoting, geroprotective, anti-inflammatory, anti-diabetic and anti-fatigue effects. In this work, we examined the functional effects of these two nutraceutical agents supplemented via pelleted chow in aging mice by examining in vivo and in vitro skeletal muscle function, along with aspects of intracellular and mitochondrial calcium homeostasis, as well as cognition and spatial memory. AX diet regimen limited weight gain compared to the control group; however, this phenomenon was not accompanied by muscle tissue mass decline. On the other hand, both AX and krill oil supplementation increased force production without altering calcium homeostasis during excitation-contraction coupling mechanism or mitochondrial calcium uptake processes. We also provide evidence of improved spatial memory and learning ability in aging mice because of krill oil supplementation. Taken together, our data favors the application of antioxidant nutraceuticals as geroprotectors to improve cognition and healthy aging by virtue of improved skeletal muscle force production.
Collapse
|
33
|
Melville Z, Kim K, Clarke OB, Marks AR. High-resolution structure of the membrane-embedded skeletal muscle ryanodine receptor. Structure 2021; 30:172-180.e3. [PMID: 34469755 DOI: 10.1016/j.str.2021.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/23/2021] [Accepted: 08/10/2021] [Indexed: 12/17/2022]
Abstract
The type 1 ryanodine receptor (RyR)/calcium release channel on the sarcoplasmic reticulum (SR) is required for skeletal muscle excitation-contraction coupling and is the largest known ion channel, composed of four 565-kDa protomers. Cryogenic electron microscopy (cryo-EM) studies of the RyR have primarily used detergent to solubilize the channel; in the present study, we have used cryo-EM to solve high-resolution structures of the channel in liposomes using a gel-filtration approach with on-column detergent removal to form liposomes and incorporate the channel simultaneously. This allowed us to resolve the structure of the channel in the primed and open states at 3.4 and 4.0 Å, respectively, with a single dataset. This method offers validation for detergent-based structures of the RyR and offers a starting point for utilizing a chemical gradient mimicking the SR, where Ca2+ concentrations are millimolar in the lumen and nanomolar in the cytosol.
Collapse
Affiliation(s)
- Zephan Melville
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians & Surgeons, New York, NY, USA
| | - Kookjoo Kim
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians & Surgeons, New York, NY, USA
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians & Surgeons, New York, NY, USA; Department of Anesthesiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians & Surgeons, New York, NY, USA; Clyde & Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians & Surgeons, New York, NY, USA.
| |
Collapse
|
34
|
Watanabe D, Ikegami R, Kano Y. Predominant cause of faster force recovery in females than males after intense eccentric contractions in mouse fast-twitch muscle. J Physiol 2021; 599:4337-4356. [PMID: 34368970 DOI: 10.1113/jp281927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/06/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We investigated the mechanisms underlying faster force recovery from eccentric contractions (ECCs) in female than in male mice, focusing on mitochondrial responses. At 3 days after repeated ECCs (REC3), female mice showed faster recovery from ECC-induced force depression than male mice. At REC3, the mitochondria in females displayed superior responses to those in males: (i) mitochondrial Ca2+ uniporter content of muscles at REC3 was higher than that of rested muscles in females, and (ii) mitochondrial volume density in females was higher than that in males at REC3. Ovariectomized (OVX) female mice showed lower mitochondrial responses at REC3, similar to those observed in male mice, but oestrogen replacement nullified such lower responses in OVX. We concluded that: (i) superior mitochondrial responses after ECCs, at least in part, cause faster force recovery from ECCs in females than in males, and (ii) oestrogen contributes to such superior responses in the mitochondria in females. ABSTRACT The purpose of this study was to investigate the mechanisms underlying sex differences in force recovery after eccentric contractions (ECCs). The left limbs of female and male mice were exposed to repeated ECCs (five sets of 50 contractions) elicited in vivo in the plantar flexor muscles. Isometric torques were measured before, immediately and at 3 days after ECCs (REC3), and gastrocnemius muscles obtained at REC3 were used for biochemical and morphological analyses. At REC3, a greater torque depression at 40 Hz was observed in males than females. Additionally, the following differences were observed at REC3: (i) in males but not females, triad structure was distorted, (ii) mitochondrial Ca2+ uniporter (MCU) content was increased in females but not in males, and (iii) mitochondrial volume density at REC3 was lower in males than in females. To examine the contribution of oestrogen to torque recovery, female mice were assigned to sham-operated (Sham), ovariectomized (OVX) and OVX treated with 17β-oestradiol (OVX + E2) groups. At REC3, (i) greater torque depression at 40 Hz was observed in the OVX group than in the Sham and OVX + E2 groups, (ii) MCU content was increased in the Sham and OVX + E2 groups but not the OVX group, and (iii) mitochondrial volume density at REC3 was lower in the OVX group than the Sham and OVX + E2 groups. These results suggest that faster force recovery in females than in males is, at least partly, ascribable to superior mitochondrial responses, and oestrogen supplementation, in part, enhances such responses.
Collapse
Affiliation(s)
- Daiki Watanabe
- Graduate School of Humanity and Social Sciences, Hiroshima University, Hiroshima, Japan
| | - Ryo Ikegami
- Department of Physical Therapy, Niigata University of Health and Welfare, Niigata, Japan
| | - Yutaka Kano
- Department of Engineering Sciences, Center for Neuroscience and Biomedical Engineering (CNBE), University of Electro-Communications, Tokyo, Japan
| |
Collapse
|
35
|
Genchev GZ, Kobayashi M, Kobayashi T, Lu H. Molecular dynamics provides new insights into the mechanism of calcium signal transduction and interdomain interactions in cardiac troponin. FEBS Open Bio 2021; 11:1841-1853. [PMID: 33085832 PMCID: PMC8255835 DOI: 10.1002/2211-5463.13009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 10/05/2020] [Accepted: 10/17/2020] [Indexed: 12/16/2022] Open
Abstract
Understanding the regulation of cardiac muscle contraction at a molecular level is crucial for the development of therapeutics for heart conditions. Despite the availability of atomic structures of the protein components of cardiac muscle thin filaments, detailed insights into their dynamics and response to calcium are yet to be fully depicted. In this study, we used molecular dynamics simulations of the core domains of the cardiac muscle protein troponin to characterize the equilibrium dynamics of its calcium-bound and calcium-free forms, with a focus on elements of cardiac muscle contraction activation and deactivation, that is, calcium binding to the cardiac troponin Ca2+ -binding subunit (TnC) and the release of the switch region of the troponin inhibitory subunit (TnI) from TnC. The process of calcium binding to the TnC binding site is described as a three-step process commencing with calcium capture by the binding site residues, followed by cooperative residue interplay bringing the calcium ion to the binding site, and finally, calcium-water exchange. Furthermore, we uncovered a set of TnC-TnI interdomain interactions that are critical for TnC N-lobe hydrophobic pocket dynamics. Absence of these interactions allows the closure of the TnC N-lobe hydrophobic pocket while the TnI switch region remains expelled, whereas if the interactions are maintained, the hydrophobic pocket remains open. Modification of these interactions may fine-tune the ability of the TnC N-lobe hydrophobic pocket to close or remain open, modulate cardiac contractility and present potential therapy-relevant targets.
Collapse
Affiliation(s)
- Georgi Z Genchev
- Center for Biomedical Informatics, Shanghai Children's Hospital, Shanghai, China.,SJTU-Yale Joint Center for Biostatistics, Shanghai Jiao Tong University, Shanghai, China.,Bulgarian Institute for Genomics and Precision Medicine, Sofia, Bulgaria.,Bioinformatics Program, Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Minae Kobayashi
- Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago College of Medicine, Chicago, IL, USA
| | - Tomoyoshi Kobayashi
- Department of Physiology and Biophysics and Center for Cardiovascular Research, University of Illinois at Chicago College of Medicine, Chicago, IL, USA
| | - Hui Lu
- Center for Biomedical Informatics, Shanghai Children's Hospital, Shanghai, China.,SJTU-Yale Joint Center for Biostatistics, Shanghai Jiao Tong University, Shanghai, China.,Department of Bioinformatics and Biostatistics, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
36
|
Luo S, Rosen SM, Li Q, Agrawal PB. Striated Preferentially Expressed Protein Kinase (SPEG) in Muscle Development, Function, and Disease. Int J Mol Sci 2021; 22:5732. [PMID: 34072258 DOI: 10.3390/ijms22115732] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
Mutations in striated preferentially expressed protein kinase (SPEG), a member of the myosin light chain kinase protein family, are associated with centronuclear myopathy (CNM), cardiomyopathy, or a combination of both. Burgeoning evidence suggests that SPEG plays critical roles in the development, maintenance, and function of skeletal and cardiac muscles. Here we review the genotype-phenotype relationships and the molecular mechanisms of SPEG-related diseases. This review will focus on the progress made toward characterizing SPEG and its interacting partners, and its multifaceted functions in muscle regeneration, triad development and maintenance, and excitation-contraction coupling. We will also discuss future directions that are yet to be investigated including understanding of its tissue-specific roles, finding additional interacting proteins and their relationships. Understanding the basic mechanisms by which SPEG regulates muscle development and function will provide critical insights into these essential processes and help identify therapeutic targets in SPEG-related disorders.
Collapse
|
37
|
Douard M. New insights into heart failure during this challenging time. J Physiol 2021; 599:3263-3265. [PMID: 33963562 DOI: 10.1113/jp281300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/04/2021] [Indexed: 11/08/2022] Open
Affiliation(s)
- Matthieu Douard
- INSERM, Bordeaux Cardiothoracic Research Center, Bordeaux, U1045, France.,Bordeaux Cardiothoracic Research Center, University of Bordeaux, Bordeaux, U1045, France.,IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux University, Pessac-Bordeaux, France
| |
Collapse
|
38
|
Lopes AG, Monteiro DA, Kalinin AL. Effects of change in temperature on the cardiac contractility of broad-snouted caiman (Caiman latirostris) during digestion. J Exp Zool A Ecol Integr Physiol 2021; 335:417-425. [PMID: 33773091 DOI: 10.1002/jez.2457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/07/2022]
Abstract
In many reptiles, digestion has been associated with the selection of higher body temperatures, the so-called post-prandial thermophilic response. This study aimed to investigate the excitation-contraction (E-C) coupling in postprandial broad-snouted caimans (Caiman latirostris) in response to acute warming within a preferred body temperature range of crocodiles. Isometric preparations subjected to a temperature transition from 25°C to 30°C were used to investigate myocardial contractility of postprandial caimans, that is, 48 h after the animals ingested a rodent meal corresponding to 15% of body mass. The caiman heart exhibits a negative force-frequency relationship that is independent of the temperature. At 25°C, cardiac muscle was able to maintain a constant force up to 36 bpm, above which it decreased significantly, reaching minimum values at the highest frequency of 84 bpm. Moreover, E-C coupling is predominantly dependent on transsarcolemmal Ca2+ transport denoted by the lack of significant ryanodine effects on force generation. On the contrary, ventricular strips at 30°C were able to sustain the cardiac contractility at higher pacing frequencies (from 12 to 144 bpm) due to an important role of Na+ /Ca2+ exchanger in Ca2+ cycling, as indicated by the decay of the post-rest contraction, and a significant contribution of the sarcoplasmic reticulum above 72 bpm. Our results demonstrated that the myocardium of postprandial caimans exhibits a significant degree of thermal plasticity of E-C coupling during acute warming. Therefore, myocardial contractility can be maximized when postprandial broad-snouted caimans select higher body temperatures (preferred temperature zone) following feeding.
Collapse
Affiliation(s)
- André G Lopes
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil.,Joint Graduate Program in Physiological Sciences, Federal University of São Carlos-UFSCar/São Paulo State University, UNESP Campus Araraquara, Araraquara, São Paulo, Brazil
| | - Diana A Monteiro
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil
| | - Ana L Kalinin
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil
| |
Collapse
|
39
|
Kreitmeier KG, Tarnowski D, Nanadikar MS, Baier MJ, Wagner S, Katschinski DM, Maier LS, Sag CM. CaMKII δ Met281/282 oxidation is not required for recovery of calcium transients during acidosis. Am J Physiol Heart Circ Physiol 2021; 320:H1199-H1212. [PMID: 33449853 DOI: 10.1152/ajpheart.00040.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 12/15/2020] [Accepted: 01/11/2021] [Indexed: 12/31/2022]
Abstract
CaMKII is needed for the recovery of Ca2+ transients during acidosis but also mediates postacidic arrhythmias. CaMKIIδ can sustain its activity following Met281/282 oxidation. Increasing cytosolic Na+ during acidosis as well as postacidic pH normalization should result in prooxidant conditions within the cell favoring oxidative CaMKIIδ activation. We tested whether CaMKIIδ activation through Met281/282 oxidation is involved in recovery of Ca2+ transients during acidosis and promotes cellular arrhythmias post-acidosis. Single cardiac myocytes were isolated from a well-established mouse model in which CaMKIIδ was made resistant to oxidative activation by knock-in replacement of two oxidant-sensitive methionines (Met281/282) with valines (MM-VV). MM-VV myocytes were exposed to extracellular acidosis (pHo 6.5) and compared to wild type (WT) control cells. Full recovery of Ca2+ transients was observed in both WT and MM-VV cardiac myocytes during late-phase acidosis. This was associated with comparably enhanced sarcoplasmic reticulum Ca2+ load and preserved CaMKII specific phosphorylation of phospholamban at Thr17 in MM-VV myocytes. CaMKII was phosphorylated at Thr287, but not Met281/282 oxidized. In line with this, postacidic cellular arrhythmias occurred to a similar extent in WT and MM-VV cells, whereas inhibition of CaMKII using AIP completely prevented recovery of Ca2+ transients during acidosis and attenuated postacidic arrhythmias in MM-VV cells. Using genetically altered cardiomyocytes with cytosolic expression of redox-sensitive green fluorescent protein-2 coupled to glutaredoxin 1, we found that acidosis has a reductive effect within the cytosol of cardiac myocytes despite a significant acidosis-related increase in cytosolic Na+. Our study shows that activation of CaMKIIδ through Met281/282 oxidation is neither required for recovery of Ca2+ transients during acidosis nor relevant for postacidic arrhythmogenesis in isolated cardiac myocytes. Acidosis reduces the cytosolic glutathione redox state of isolated cardiac myocytes despite a significant increase in cytosolic Na+. Pharmacological inhibition of global CaMKII activity completely prevents recovery of Ca2+ transients and protects from postacidic arrhythmias in MM-VV myocytes, which confirms the relevance of CaMKII in the context of acidosis.NEW & NOTEWORTHY The current study shows that activation of CaMKIIδ through Met281/282 oxidation is neither required for CaMKII-dependent recovery of Ca2+ transients during acidosis nor relevant for the occurrence of postacidic cellular arrhythmias. Despite a usually prooxidant increase in cytosolic Na+, acidosis reduces the cytosolic glutathione redox state within cardiac myocytes. This novel finding suggests that oxidation of cytosolic proteins is less likely to occur during acidosis.
Collapse
Affiliation(s)
- K G Kreitmeier
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
- Department of Internal Medicine III, University Medical Center Regensburg, Germany
| | - D Tarnowski
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - M S Nanadikar
- Institute for Cardiovascular Physiology, Georg August University, Göttingen, Germany
| | - M J Baier
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - S Wagner
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - D M Katschinski
- Institute for Cardiovascular Physiology, Georg August University, Göttingen, Germany
| | - L S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - C M Sag
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| |
Collapse
|
40
|
Boncompagni S, Pecorai C, Michelucci A, Pietrangelo L, Protasi F. Long-Term Exercise Reduces Formation of Tubular Aggregates and Promotes Maintenance of Ca 2+ Entry Units in Aged Muscle. Front Physiol 2021; 11:601057. [PMID: 33469430 PMCID: PMC7813885 DOI: 10.3389/fphys.2020.601057] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/16/2020] [Indexed: 12/16/2022] Open
Abstract
Tubular aggregates (TAs) in skeletal muscle fibers are unusual accumulation of sarcoplasmic reticulum (SR) tubes that are found in different disorders including TA myopathy (TAM). TAM is a muscular disease characterized by muscle pain, cramping, and weakness that has been recently linked to mutations in STIM1 and ORAI1. STIM1 and ORAI1 are the two main proteins mediating store-operated Ca2+ entry (SOCE), a mechanism activated by depletion of intracellular Ca2+ stores (e.g., SR) that allows recovery of Ca2+ from the extracellular space during repetitive muscle activity. We have recently shown that exercise triggers the formation of unique intracellular junctions between SR and transverse tubules named Ca 2+ entry units (CEUs). CEUs promote colocalization of STIM1 with ORAI1 and improve muscle function in presence of external Ca2+. TAs virtually identical to those of TAM patients are also found in fast-twitch fibers of aging male mice. Here, we used a combination of electron and confocal microscopy, Western blotting, and ex vivo stimulation protocols (in presence or absence of external Ca2+) to evaluate the presence of TAs, STIM1-ORAI1 localization and expression and fatigue resistance of intact extensor digitorum longus (EDL) muscles in wild-type male adult (4-month-old) and aged (24-month-old) mice and in mice trained in wheel cages for 15 months (from 9 to 24 months of age). The results collected indicate that (i) aging causes STIM1 and ORAI1 to accumulate in TAs and (ii) long-term exercise significantly reduced formation of TAs. In addition, (iii) EDL muscles from aged mice exhibited a faster decay of contractile force than adult muscles, likely caused by their inability to refill intracellular Ca2+ stores, and (iv) exercise in wheel cages restored the capability of aged EDL muscles to use external Ca2+ by promoting maintenance of CEUs. In conclusion, exercise prevented improper accumulation of STIM1 and ORAI1 in TAs during aging, maintaining the capability of aged muscle to refill intracellular Ca2+ stores via SOCE.
Collapse
Affiliation(s)
- Simona Boncompagni
- Center for Advanced Studies and Technology (CAST), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
- Department of Neuroscience, Imaging and Clinical Sciences (DNICS), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
| | - Claudia Pecorai
- Center for Advanced Studies and Technology (CAST), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
- Department of Medicine and Aging Sciences (DMSI), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
| | - Antonio Michelucci
- Center for Advanced Studies and Technology (CAST), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
- Department of Medicine and Aging Sciences (DMSI), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
| | - Laura Pietrangelo
- Center for Advanced Studies and Technology (CAST), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
- Department of Medicine and Aging Sciences (DMSI), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
| | - Feliciano Protasi
- Center for Advanced Studies and Technology (CAST), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
- Department of Medicine and Aging Sciences (DMSI), University G. d’Annunzio (Ud’A) of Chieti-Pescara, Chieti, Italy
| |
Collapse
|
41
|
Cserne Szappanos H, Vincze J, Bodnár D, Dienes B, Schneider MF, Csernoch L, Szentesi P. High Time Resolution Analysis of Voltage-Dependent and Voltage-Independent Calcium Sparks in Frog Skeletal Muscle Fibers. Front Physiol 2020; 11:599822. [PMID: 33384612 PMCID: PMC7769825 DOI: 10.3389/fphys.2020.599822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/25/2020] [Indexed: 11/29/2022] Open
Abstract
In amphibian skeletal muscle calcium (Ca2+) sparks occur both as voltage-dependent and voltage-independent ligand-activated release events. However, whether their properties and their origin show similarities are still in debate. Elevated K+, constant Cl- content solutions were used to initiate small depolarizations of the resting membrane potential to activate dihydropyridine receptors (DHPR) and caffeine to open ryanodine receptors (RyR) on intact fibers. The properties of Ca2+ sparks observed under control conditions were compared to those measured on depolarized cells and those after caffeine treatment. Calcium sparks were recorded on intact frog skeletal muscle fibers using high time resolution confocal microscopy (x-y scan: 30 Hz). Sparks were elicited by 1 mmol/l caffeine or subthreshold depolarization to different membrane potentials. Both treatments increased the frequency of sparks and altered their morphology. Images were analyzed by custom-made computer programs. Both the amplitude (in ΔF/F0; 0.259 ± 0.001 vs. 0.164 ± 0.001; n = 24942 and 43326, respectively; mean ± SE, p < 0.001) and the full width at half maximum (FWHM, in μm; parallel with fiber axis: 2.34 ± 0.01 vs. 1.92 ± 0.01, p < 0.001; perpendicular to fiber axis: 2.08 ± 0.01 vs. 1.68 ± 0.01, p < 0.001) of sparks was significantly greater after caffeine treatment than on depolarized cells. 9.8% of the sparks detected on depolarized fibers and about one third of the caffeine activated sparks (29.7%) overlapped with another one on the previous frame on x-y scans. Centre of overlapping sparks travelled significantly longer distances between consecutive frames after caffeine treatment then after depolarization (in μm; 1.66 ± 0.01 vs. 0.95 ± 0.01, p < 0.001). Our results suggest that the two types of ryanodine receptors, the junctional RyRs controlled by DHPRs and the parajunctional RyRs are activated independently, using alternate ways, with the possibility of cooperation between neighboring release channels.
Collapse
Affiliation(s)
- Henrietta Cserne Szappanos
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Vincze
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Dóra Bodnár
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Martin F. Schneider
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter Szentesi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| |
Collapse
|
42
|
DiNello E, Bovo E, Thuo P, Martin TG, Kirk JA, Zima AV, Cao Q, Kuo IY. Deletion of cardiac polycystin 2/PC2 results in increased SR calcium release and blunted adrenergic reserve. Am J Physiol Heart Circ Physiol 2020; 319:H1021-H1035. [PMID: 32946258 DOI: 10.1152/ajpheart.00302.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Transient receptor potential proteins (TRPs) act as nonselective cation channels. Of the TRP channels, PC2 (also known as polycystin 2) is localized to the sarcoplasmic reticulum (SR); however, its contribution to calcium-induced calcium release and overall cardiac function in the heart is poorly understood. The goal of this study was to characterize the effect of cardiac-specific PC2 deletion in adult cardiomyocytes and in response to chronic β-adrenergic challenge. We used a temporally inducible model to specifically delete PC2 from cardiomyocytes (Pkd2 KO) and characterized calcium and contractile dynamics in single cells. We found enhanced intracellular calcium release after Pkd2 KO, and near super-resolution microscopy analysis suggested this was due to close localization of PC2 to the ryanodine receptor. At the organ level, speckle-tracking echocardiographical analysis showed increased dyssynchrony in the Pkd2 KO mice. In response to chronic adrenergic stimulus, cardiomyocytes from the Pkd2 KO had no reserve β-adrenergic calcium responses and significantly attenuated wall motion in the whole heart. Biochemically, without adrenergic stimulus, there was an overall increase in PKA phosphorylated targets in the Pkd2 KO mouse, which decreased following chronic adrenergic stimulus. Taken together, our results suggest that cardiac-specific PC2 limits SR calcium release by affecting the PKA phosphorylation status of the ryanodine receptor, and the effects of PC2 loss are exacerbated upon adrenergic challenge.NEW & NOTEWORTHY Our goal was to characterize the role of the transient receptor potential channel polycystin 2 (PC2) in cardiomyocytes following adult-onset deletion. Loss of PC2 resulted in decreased cardiac shortening and cardiac dyssynchrony and diminished adrenergic reserve. These results suggest that cardiac-specific PC2 modulates intracellular calcium signaling and contributes to the maintenance of adrenergic pathways.
Collapse
Affiliation(s)
- Elisabeth DiNello
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois.,Cardiovascular Research Institute, Loyola University Chicago, Chicago, Illinois
| | - Elisa Bovo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois.,Cardiovascular Research Institute, Loyola University Chicago, Chicago, Illinois
| | - Paula Thuo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois.,Cardiovascular Research Institute, Loyola University Chicago, Chicago, Illinois
| | - Thomas G Martin
- Graduate School, Loyola University Chicago, Chicago, Illinois
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois.,Cardiovascular Research Institute, Loyola University Chicago, Chicago, Illinois
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois.,Cardiovascular Research Institute, Loyola University Chicago, Chicago, Illinois
| | - Quan Cao
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois.,Cardiovascular Research Institute, Loyola University Chicago, Chicago, Illinois
| | - Ivana Y Kuo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois.,Cardiovascular Research Institute, Loyola University Chicago, Chicago, Illinois.,Department of Pharmacology, Yale University, New Haven, Connecticut
| |
Collapse
|
43
|
Affiliation(s)
- Fujian Lu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China (F.L., Y.Z., Q.G., X.W., H.C.)
| | - Yan Zhao
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China (F.L., Y.Z., Q.G., X.W., H.C.).,Academy for Advanced Interdisciplinary Studies (Y.Z.), Peking University, Beijing, China
| | - Wenjun Xie
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China (W.X.)
| | - Qianjin Guo
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China (F.L., Y.Z., Q.G., X.W., H.C.)
| | - Shi-Qiang Wang
- College of Life Sciences(S-Q.W.), Peking University, Beijing, China
| | - Xianhua Wang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China (F.L., Y.Z., Q.G., X.W., H.C.).,Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, China (X.W., H.C.)
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China (F.L., Y.Z., Q.G., X.W., H.C.).,Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, China (X.W., H.C.)
| |
Collapse
|
44
|
Abstract
OBJECTIVE The aim of this study was to apply a novel method to measure excitation-contraction coupling time (ECCT) in normal soleus muscles. METHODS We performed simultaneous recordings of soleus compound muscle action potential (CMAP) and foot movement-related potential (MRP), and measured ankle plantar flexion torque in 36 healthy subjects. We calculated ECCT and examined the relations between CMAP, MRP, ECCT and ankle plantar flexion torque. RESULTS Statistical analyses established reference ranges (mean ± SE) for CMAP (13.4 ± 0.9 mV), MRP (5.3 ± 0.4 m/s2), ECCT (5.2 ± 0.1 ms), torque (85.9 ± 6.4 Nm) and torque/body weight (1.4 ± 0.1 Nm/kg). The torque showed a positive linear correlation with CMAP (p = 0.041) and a negative linear correlation with ECCT (p = 0.045). CONCLUSION Soleus ECCT can be recorded easily, and is useful to assess the impairment of E-C coupling in muscles of the lower extremities.
Collapse
Affiliation(s)
- Yuta Asada
- Sapporo Medical University Graduate School of Health Sciences, Japan
| | - Tomihiro Imai
- Sapporo Medical University Graduate School of Health Sciences, Japan
| |
Collapse
|
45
|
Hsu IU, Linsley JW, Reid LE, Hume RI, Leflein A, Kuwada JY. Dstac Regulates Excitation-Contraction Coupling in Drosophila Body Wall Muscles. Front Physiol 2020; 11:573723. [PMID: 33123029 PMCID: PMC7573238 DOI: 10.3389/fphys.2020.573723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/15/2020] [Indexed: 12/13/2022] Open
Abstract
Stac3 regulates excitation-contraction coupling (EC coupling) in vertebrate skeletal muscles by regulating the L-type voltage-gated calcium channel (Cav channel). Recently a stac-like gene, Dstac, was identified in Drosophila and found to be expressed by both a subset of neurons and muscles. Here, we show that Dstac and Dmca1D, the Drosophila L-type Cav channel, are necessary for normal locomotion by larvae. Immunolabeling with specific antibodies against Dstac and Dmca1D found that Dstac and Dmca1D are expressed by larval body-wall muscles. Furthermore, Ca2+ imaging of muscles of Dstac and Dmca1D deficient larvae found that Dstac and Dmca1D are required for excitation-contraction coupling. Finally, Dstac appears to be required for normal expression levels of Dmca1D in body-wall muscles. These results suggest that Dstac regulates Dmca1D during EC coupling and thus muscle contraction.
Collapse
Affiliation(s)
- I-Uen Hsu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Jeremy W Linsley
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, United States
| | - Lilly E Reid
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Richard I Hume
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Ari Leflein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - John Y Kuwada
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States.,Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, United States
| |
Collapse
|
46
|
Durland L. Distinguishing HF with reduced and preserved ejection fraction at the level of individual cardiomyocytes: implications for therapeutic development. J Physiol 2020; 599:1027-1029. [PMID: 33017063 DOI: 10.1113/jp280739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
|
47
|
Bode D, Wen Y, Hegemann N, Primessnig U, Parwani A, Boldt LH, M Pieske B, R Heinzel F, Hohendanner F. Oxidative Stress and Inflammatory Modulation of Ca 2+ Handling in Metabolic HFpEF-Related Left Atrial Cardiomyopathy. Antioxidants (Basel) 2020; 9:E860. [PMID: 32937823 DOI: 10.3390/antiox9090860] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 12/17/2022] Open
Abstract
Metabolic syndrome-mediated heart failure with preserved ejection fraction (HFpEF) is commonly accompanied by left atrial (LA) cardiomyopathy, significantly affecting morbidity and mortality. We evaluate the role of reactive oxygen species (ROS) and intrinsic inflammation (TNF-α, IL-10) related to dysfunctional Ca2+ homeostasis of LA cardiomyocytes in a rat model of metabolic HFpEF. ZFS-1 obese rats showed features of HFpEF and atrial cardiomyopathy in vivo: increased left ventricular (LV) mass, E/e’ and LA size and preserved LV ejection fraction. In vitro, LA cardiomyocytes exhibited more mitochondrial-fission (MitoTracker) and ROS-production (H2DCF). In wildtype (WT), pro-inflammatory TNF-α impaired cellular Ca2+ homeostasis, while anti-inflammatory IL-10 had no notable effect (confocal microscopy; Fluo-4). In HFpEF, TNF-α had no effect on Ca2+ homeostasis associated with decreased TNF-α receptor expression (western blot). In addition, IL-10 substantially improved Ca2+ release and reuptake, while IL-10 receptor-1 expression was unaltered. Oxidative stress in metabolic syndrome mediated LA cardiomyopathy was increased and anti-inflammatory treatment positively affected dysfunctional Ca2+ homeostasis. Our data indicates, that patients with HFpEF-related LA dysfunction might profit from IL-10 targeted therapy, which should be further explored in preclinical trials.
Collapse
|
48
|
Aitken-Buck HM, Krause J, Zeller T, Jones PP, Lamberts RR. Long-Chain Acylcarnitines and Cardiac Excitation-Contraction Coupling: Links to Arrhythmias. Front Physiol 2020; 11:577856. [PMID: 33041874 PMCID: PMC7518131 DOI: 10.3389/fphys.2020.577856] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/25/2020] [Indexed: 12/31/2022] Open
Abstract
A growing number of metabolomic studies have associated high circulating levels of the amphiphilic fatty acid metabolites, long-chain acylcarnitines (LCACs), with cardiovascular disease (CVD) risk. These studies show that plasma LCAC levels can be correlated with the stage and severity of CVD and with indices of cardiac hypertrophy and ventricular function. Complementing these recent clinical associations is an extensive body of basic research that stems mostly from the twentieth century. These works, performed in cardiomyocyte and multicellular preparations from animal and cell models, highlight stereotypical derangements in cardiac electrophysiology induced by exogenous LCAC treatment that promote arrhythmic muscle behavior. In many cases, this is coupled with acute inotropic modulation; however, whether LCACs increase or decrease contractility is inconclusive. Linked to the electromechanical alterations induced by LCAC exposure is an array of effects on cardiac excitation-contraction coupling mechanisms that overload the cardiomyocyte cytosol with Na+ and Ca2+ ions. The aim of this review is to revisit this age-old literature and collate it with recent findings to provide a pathophysiological context for the growing body of metabolomic association studies that link circulating LCACs with CVD.
Collapse
Affiliation(s)
- Hamish M Aitken-Buck
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Julia Krause
- University Heart and Vascular Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Hamburg, Hamburg, Germany
| | - Tanja Zeller
- University Heart and Vascular Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Hamburg, Hamburg, Germany
| | - Peter P Jones
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Regis R Lamberts
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| |
Collapse
|
49
|
Kilfoil PJ, Lotteau S, Zhang R, Yue X, Aynaszyan S, Solymani RE, Cingolani E, Marbán E, Goldhaber JI. Distinct features of calcium handling and β-adrenergic sensitivity in heart failure with preserved versus reduced ejection fraction. J Physiol 2020; 598:5091-5108. [PMID: 32829489 PMCID: PMC7693093 DOI: 10.1113/jp280425] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/19/2020] [Indexed: 12/21/2022] Open
Abstract
Key points Heart failure (HF), the leading cause of death in developed countries, occurs in the setting of reduced (HFrEF) or preserved (HFpEF) ejection fraction. Unlike HFrEF, there are no effective treatments for HFpEF, which accounts for ∼50% of heart failure. Abnormal intracellular calcium dynamics in cardiomyocytes have major implications for contractility and rhythm, but compared to HFrEF, very little is known about calcium cycling in HFpEF. We used rat models of HFpEF and HFrEF to reveal distinct differences in intracellular calcium regulation and excitation‐contraction (EC) coupling. While HFrEF is characterized by defective EC coupling at baseline, HFpEF exhibits enhanced coupling fidelity, further aggravated by a reduction in β‐adrenergic sensitivity. These differences in EC coupling and β‐adrenergic sensitivity may help explain why therapies that work in HFrEF are ineffective in HFpEF.
Abstract Heart failure with reduced or preserved ejection fraction (respectively, HFrEF and HFpEF) is the leading cause of death in developed countries. Although numerous therapies improve outcomes in HFrEF, there are no effective treatments for HFpEF. We studied phenotypically verified rat models of HFrEF and HFpEF to compare excitation‐contraction (EC) coupling and protein expression in these two forms of heart failure. Dahl salt‐sensitive rats were fed a high‐salt diet (8% NaCl) from 7 weeks of age to induce HFpEF. Impaired diastolic relaxation and preserved ejection fraction were confirmed in each animal echocardiographically, and clinical signs of heart failure were documented. To generate HFrEF, Sprague‐Dawley (SD) rats underwent permanent left anterior descending coronary artery ligation which, 8–10 weeks later, led to systolic dysfunction (verified echocardiographically) and clinical signs of heart failure. Calcium (Ca2+) transients were measured in isolated cardiomyocytes under field stimulation or patch clamp. Ultra‐high‐speed laser scanning confocal imaging captured Ca2+ sparks evoked by voltage steps. Western blotting and PCR were used to assay changes in EC coupling protein and RNA expression. Cardiomyocytes from rats with HFrEF exhibited impaired EC coupling, including decreased Ca2+ transient (CaT) amplitude and defective couplon recruitment, associated with transverse (t)‐tubule disruption. In stark contrast, HFpEF cardiomyocytes showed saturated EC coupling (increased ICa, high probability of couplon recruitment with greater Ca2+ release synchrony, increased CaT) and preserved t‐tubule integrity. β‐Adrenergic stimulation of HFpEF myocytes with isoprenaline (isoproterenol) failed to elicit robust increases in ICa or CaT and relaxation kinetics. Fundamental differences in EC coupling distinguish HFrEF from HFpEF. Heart failure (HF), the leading cause of death in developed countries, occurs in the setting of reduced (HFrEF) or preserved (HFpEF) ejection fraction. Unlike HFrEF, there are no effective treatments for HFpEF, which accounts for ∼50% of heart failure. Abnormal intracellular calcium dynamics in cardiomyocytes have major implications for contractility and rhythm, but compared to HFrEF, very little is known about calcium cycling in HFpEF. We used rat models of HFpEF and HFrEF to reveal distinct differences in intracellular calcium regulation and excitation‐contraction (EC) coupling. While HFrEF is characterized by defective EC coupling at baseline, HFpEF exhibits enhanced coupling fidelity, further aggravated by a reduction in β‐adrenergic sensitivity. These differences in EC coupling and β‐adrenergic sensitivity may help explain why therapies that work in HFrEF are ineffective in HFpEF.
Collapse
Affiliation(s)
- Peter J Kilfoil
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA, USA
| | - Sabine Lotteau
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA, USA
| | - Rui Zhang
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA, USA
| | - Xin Yue
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Stephan Aynaszyan
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA, USA
| | - Ryan E Solymani
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA, USA
| | - Eugenio Cingolani
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA, USA
| | - Eduardo Marbán
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA, USA
| | - Joshua I Goldhaber
- Cedars-Sinai Medical Center, Smidt Heart Institute, Los Angeles, CA, USA
| |
Collapse
|
50
|
Firth JM, Yang HY, Francis AJ, Islam N, MacLeod KT. The Effect of Estrogen on Intracellular Ca 2+ and Na + Regulation in Heart Failure. ACTA ACUST UNITED AC 2020; 5:901-912. [PMID: 33015413 PMCID: PMC7524784 DOI: 10.1016/j.jacbts.2020.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/31/2022]
Abstract
During the progression toward heart failure, indicators of in vivo whole-heart function suggest greater impairment in the absence of estrogen. At the single cardiac myocyte level, the absence of estrogen results in further reduction of Ca2+ transient amplitudes, further slowing of transient decay kinetics, less SR Ca2+ content, and a further increase in Ca2+ spark frequencies and spark-mediated SR leak compared with animals with normal estrus cycles. Cardiac myocyte Na+ regulation is also more disrupted in the absence of estrogen.
Contradictory findings of estrogen supplementation in cardiac disease highlight the need to investigate the involvement of estrogen in the progression of heart failure in an animal model that lacks traditional comorbidities. Heart failure was induced by aortic constriction (AC) in female guinea pigs. Selected AC animals were ovariectomized (ACOV), and a group of these received 17β-estradiol supplementation (ACOV+E). One hundred-fifty days post-AC surgery, left-ventricular myocytes were isolated, and their electrophysiology and Ca2+ and Na+ regulation were examined. Long-term absence of ovarian hormones exacerbates the decline in cardiac function during the progression to heart failure. Estrogen supplementation reverses these aggravating effects.
Collapse
Key Words
- AC, aortic constriction
- ACOV+E, aortic constriction with ovariectomy, supplemented with 17β-estradiol
- ACOV, aortic constriction with ovariectomy
- FS, fractional shortening
- ICa, l-type Ca2+ channel current (cadmium-sensitive)
- INa,L, late Na+ current (ranolazine-sensitive)
- NCX, Na+/Ca2+ exchange
- OV, ovariectomy
- SERCA, Sarco/endoplasmic reticulum Ca2+-ATPase
- SR, sarcoplasmic reticulum
- calcium regulation
- cardiomyocytes
- estrogen
- excitation-contraction coupling
- female
- heart failure
Collapse
Affiliation(s)
- Jahn M Firth
- National Heart and Lung Institute, Imperial College, Hammersmith Hospital, London, United Kingdom
| | - Hsiang-Yu Yang
- Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (R.O.C.)
| | - Alice J Francis
- National Heart and Lung Institute, Imperial College, Hammersmith Hospital, London, United Kingdom
| | - Najah Islam
- National Heart and Lung Institute, Imperial College, Hammersmith Hospital, London, United Kingdom
| | - Kenneth T MacLeod
- National Heart and Lung Institute, Imperial College, Hammersmith Hospital, London, United Kingdom
| |
Collapse
|