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Cardiac calcium signaling in health and disease: role of SR Ca2+ release and ryanodine receptor release channels (RyRs)

English title Cardiac calcium signaling in health and disease: role of SR Ca2+ release and ryanodine receptor release channels (RyRs)
Applicant Niggli Ernst
Number 179325
Funding scheme Project funding (Div. I-III)
Research institution Institut für Physiologie Medizinische Fakultät Universität Bern
Institution of higher education University of Berne - BE
Main discipline Cardiovascular Research
Start/End 01.06.2018 - 30.11.2020
Approved amount 313'664.00
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All Disciplines (2)

Discipline
Cardiovascular Research
Physiology : other topics

Keywords (6)

cardiomyocyte; ryanodine receptor; cardiac muscle; excitation-contraction coupling; calcium signaling; sarcoplasmic reticulum

Lay Summary (German)

Lead
Bei vielen Herzkrankheiten führt eine Beeinträchtigung der zellulären Kalziumsignale zu einer Schwächung des Herzmuskels. In diesem Projekt wird die Funktion der Proteine, welche diese Signale kontrollieren, untersucht. Das Verständnis von pathologischen Funktionsänderungen dieser Proteine wird die Entwicklung neuer Therapiekonzepte ermöglichen.
Lay summary

intergrund:

Seit geraumer Zeit ist bekannt, dass die Funktion des Kalziumsignalsystems der Herzmuskelzellen bei vielen Krankheiten gestört ist. Dieser Umstand ist für die inadäquate Herzmuskelkraft in solchen Situationen verantwortlich, aber auch für Rhythmusstörungen des Herzens. Jede Herzmuskelzelle besitzt einen eingebauten “Verstärker” für Kalziumsignale, bestehend aus einem Kalziumspeicher (das sarkoplasmatische Retikulum), Kanalproteinen zur Kalziumfreisetzung, und sogenannte Kalziumpumpen zum Wiederauffüllen des Speichers. Krankheitsbedingte oder vererbbare Veränderungen der Funktion der Kanalproteine, auch Ryanodinrezeptoren genannt, stehen im Zentrum dieses Projekts, da diese zu Herzmuskelschwäche und lebensbedrohlichen Herzrhythmusstörungen führen können, ja sogar zum plötzlichen Herztod.

Ziel:

In diesem Projekt werden wir Funktionsänderungen dieser Kanalproteine, wie sie im Rahmen verschiedener physiologischer regulatorischer Vorgänge oder bei Erkrankungen auftreten können, mit biophysikalischen und bildgebenden Methoden an isolierten Herzmuskelzellen untersuchen. Wir werden die Hypothese testen, dass verschiedene Störungen letzten Endes ganz ähnliche und zum Teil additive Funktionsänderungen dieser Kanäle bewirken. Zu den Störungen gehören zum Beispiel Funktionsänderungen infolge von Stress, aber auch vererbbare Mutationen in diesem Kanal.

Bedeutung:

Erkrankungen des Herz-Kreislaufsystems sind nach wie vor die wichtigste Todesursache in allen Industrienationen. Herzmuskelschwäche ist medikamentös leider immer noch nicht adäquat behandelbar, aber deren Häufigkeit nimmt in der alternden Bevölkerung stetig zu und wird endemische Proportionen annehmen. Ein verbessertes Verständnis der zugrunde liegenden Pathomechanismen wird für die zukünftige Entwicklung neuer Behandlungsmethoden von zentraler Bedeutung sein.

 
Direct link to Lay Summary Last update: 09.04.2018

Responsible applicant and co-applicants

Employees

Project partner

Publications

Publication
Activation of endogenous protein phosphatase 1 enhances the calcium sensitivity of the ryanodine receptor type 2 in murine ventricular cardiomyocytes
Potenza Duilio Michele, Janicek Radoslav, Fernandez‐Tenorio Miguel, Niggli Ernst (2020), Activation of endogenous protein phosphatase 1 enhances the calcium sensitivity of the ryanodine receptor type 2 in murine ventricular cardiomyocytes, in The Journal of Physiology, JP278951-JP278951.
Automatic Detection and Classification of Ca2+ Release Events in Confocal Line- and Frame-scan Images
Illaste Ardo, Wullschleger Marcel, Fernandez-Tenorio Miguel, Niggli Ernst, Egger Marcel (2019), Automatic Detection and Classification of Ca2+ Release Events in Confocal Line- and Frame-scan Images, in Biophysical Journal, 116, 383-394.
Phosphorylation of the ryanodine receptor 2 at serine 2030 is required for a complete β-adrenergic response
Potenza Duilio M., Janicek Radoslav, Fernandez-Tenorio Miguel, Camors Emmanuel, Ramos-Mondragón Roberto, Valdivia Héctor H., Niggli Ernst (2019), Phosphorylation of the ryanodine receptor 2 at serine 2030 is required for a complete β-adrenergic response, in Journal of General Physiology, 151, 131-145.
Calcium-Binding Proteins of the EF-Hand SuperfamilyFrom Basics to Medical Applications
Niggli Ernst, Fernandez-Tenorio Miguel (2019), Calcium-Binding Proteins of the EF-Hand SuperfamilyFrom Basics to Medical Applications, in Heizmann Claus W. (ed.), Springer New York, New York, NY, 53-71.
Caged Compounds: Applications in Cardiac Muscle Research
Niggli Ernst, Shirokova Natalia (2018), Caged Compounds: Applications in Cardiac Muscle Research, in Kästner Lars (ed.), Springer International Publishing, Cham, 75-95.
Duchenne Muscular Dystrophy: Emerging Pathological Role for Cardiac Myopathy
Shirokova Natalia, Niggli Ernst (2018), Duchenne Muscular Dystrophy: Emerging Pathological Role for Cardiac Myopathy, in Kardiologiia: vid nauky do praktyky, 4 (33), 27-40.

Datasets

Activation of endogenous protein phosphatase 1 enhances the calcium sensitivity of the ryanodine receptor type 2 in murine ventricular cardiomyocytes

Author Niggli, Ernst
Publication date 20.01.2020
Persistent Identifier (PID) 10.5281/zenodo.3516636
Repository Zenodo
Abstract
Each ZIP file contains the confocal or Western blot images (.tif, .oib, .oif) as well as voltage-clamp recordings (.pxp files - Igor, Wavemetrics). It also contains the analyses of the data used in that figure. Data are organised by dates (cell isolations) and by measured cells.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Annual Meeting of the Biophysical Society 2020 Poster The RyR2R420Q+/- Mutation Triggers Arrhythmogenic Ca2+ Events in Mouse Cardiomyocytes 01.02.2020 San Diego, United States of America Lopez Dicuru Ruben José; Niggli Ernst; Janicek Radoslav;
98th Meeting of the German Physiological Society Poster Activation of endogenous PP1 enhances calcium spark activity in wild type cardiomyocytes 30.09.2019 Ulm, Germany Lopez Dicuru Ruben José; Niggli Ernst; Potenza Duilio Michele;
Gordon Conference: Muscle: Excitation-Contraction Coupling 2019 Poster The RyR2R420Q+/- Mutation Triggers Arrhythmogenic Ca2+ Events in Mouse Cardiomyocytes. 19.05.2019 Lucca, Italy Potenza Duilio Michele; Janicek Radoslav; Lopez Dicuru Ruben José; Niggli Ernst;
Cardiovascular Research Meeting 2019 LS2 Talk given at a conference Activation of endogenous PP1 enhances calcium spark activity in wild type cardiomyocytes 14.03.2019 Fribourg, Switzerland Lopez Dicuru Ruben José; Potenza Duilio Michele; Niggli Ernst;
Annual Meeting of the Biophysical Society 2019 Poster Activation of Endogenous PP1 Enhances Calcium Spark Activity in Wild Type Cardiomyocytes. 02.03.2019 Baltimore, United States of America Janicek Radoslav; Niggli Ernst;


Awards

Title Year
Cardiovascular Research Meeting 2019 in Fribourg, Best oral presentation award 2019

Associated projects

Number Title Start Funding scheme
156375 Cardiac calcium signaling in health and disease: role of SR Ca2+ release and ryanodine receptor release channels (RyRs) 01.10.2014 Project funding (Div. I-III)

Abstract

1.1. Background and rationale:In cardiac muscle, contraction is activated by transient elevations of the intracellular Ca2+ concentration. The mechanisms governing these Ca2+ signals are referred to as excitation-contraction (EC) coupling. A small amount of Ca2+ entering the myocytes via voltage-dependent Ca2+ channels is amplified several-fold by the mechanism of Ca2+-induced Ca2+ release (CICR) from the sarcoplasmic reticulum (SR) via Ca2+ release channels (called ryanodine receptors or RyRs). The RyRs are thus the gatekeepers of EC-coupling. Opening and closing of the RyRs is modulated by a variety of post-translational modifications, and by cellular constituents and ions. The overarching goal of this project is to define the function of the RyRs in health and disease, and to characterize how these channels shape Ca2+ signaling and can cause arrhythmogenicity. We will concentrate our experimental efforts on 2 parameters, carefully selected because of their importance in physiological regulation of cardiac muscle activity, but also because of their pathophysiological and clinical relevance. The following mechanisms will be examined: 1) Regulation and mis-regulation of RyR activity by RyR phosphorylation. 2) Mis-regulation of RyR activity resulting from a arrhythmogenic RyR mutation. In addition, we will define how the two mechanisms interact, i.e. whether and how RyR phosphorylation may trigger the life-threatening arrhythmias in patients harboring this RyR mutation.1.2. Working hypothesis: We hypothesize that phosphorylation of the RyR, particularly at the under-explored S2030 site, affects the Ca2+ sensitivity of the RyR channel (aim 1). This increase of Ca2+ sensitivity would also have strong repercussions in channels with the RyRR420Q mutation, and could actually precipitate the catecholaminergic polymorphic ventricular tachycardia (CPVT) during physical or emotional stress (aim 2). The simultaneously occurring SERCA stimulation could have additional ramifications for such changes of RyR Ca2+ sensitivity.1.3. Specific aims: The proposal hast two connected aims. Aim 1: To define the functional role of the RyR2-S2030 phosphorylation site from the near-molecular to the cellular level, and its interaction with other known phosphorylation sites. Aim 2 is to characterize altered Ca2+ signaling (cytosolic, SR) in the presence of the RyRR420Q CPVT mutation and, as a sub-aim, to define the role of SERCA stimulation and RyR phosphorylation (occurring in parallel during stress) in precipitating the actual arrhythmia.1.4. Experimental design: We will use transgenic mouse models and a broad variety of approaches to specifically interrogate Ca2+ signaling from the near molecular to the cellular level (in isolated cardiomyocytes). The RyR-S2814A/2808A double knock-in mouse has the two major RyR phosphorylation sites removed, but retains the S2030 site. These findings will be complemented by results from the running project on the S2030A mouse, in which the RyR lacks this site but retains the two others. Functional consequences of the arrhythmogenic RyRR420Q mutation will be examined in transgenic mice harboring this mutation and recapitulating the human disease. 1.5. Specific methods: Confocal imaging of Ca2+ signals (transients, sparks, waves) in isolated cardiomyocytes will be combined with electrophysiology techniques (patch-clamp) and photolysis of caged compounds, a combination of techniques that was pioneered by our laboratory. Intact and permeabilized myocytes will be used for the proposed studies, the latter mainly for recordings of Ca2+ signals from inside the SR. To derive information about the RyR function under specific conditions, we will analyze Ca2+ spark parameters (e.g. frequency, amplitude, restitution) and intra-SR Ca2+ concentration and wave thresholds. This will be complemented by Western blotting, to quantify protein expression and extent of site-specific RyR phosphorylation. Pharmacological tools will allow manipulation of signaling pathways. A recently adopted technique enables specific SERCA stimulation, using Fab fragments of a PLB antibody.1.6. Expected value of the proposed project:With the proposed experiments we expect to obtain new information about fundamental cellular and molecular mechanisms that enable the heart to regulate the produced force and how this regulation may be impaired in cardiac diseases, some of which lead to arrhythmias. The RyRs and the SERCAs are considered to be promising drug targets and new pharmacological compounds stabilizing the RyRs and activating SERCA are under development. Thus, besides our genuine interest to comprehend the functioning of cardiac Ca2+ signaling, a detailed mechanistic and patho-mechanistic understanding of the RyRs and their interplay with SERCA activity is of crucial importance. With the approach presented here we hope to gain key information about some of these important mechanisms and how they interact synergistically or deleteriously, by their ability to change RyR function in favorable or harmful ways, particularly in patients with HF or those carrying arrhythmogenic RyR mutations.
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