1
|
Hu J, Venturi E, Sigalas C, Murayama T, Nishi M, Takeshima H, Sitsapesan R. The biophysical properties of TRIC-A and TRIC-B and their interactions with RyR2. J Gen Physiol 2023; 155:e202113070. [PMID: 37756589 PMCID: PMC10522464 DOI: 10.1085/jgp.202113070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 08/07/2023] [Indexed: 09/29/2023] Open
Abstract
Trimeric intracellular cation channels (TRIC-A and TRIC-B) are thought to provide counter-ion currents to enable charge equilibration across the sarco/endoplasmic reticulum (SR) and nuclear membranes. However, there is also evidence that TRIC-A may interact directly with ryanodine receptor type 1 (RyR1) and 2 (RyR2) to alter RyR channel gating. It is therefore possible that the reverse is also true, where the presence of RyR channels is necessary for fully functional TRIC channels. We therefore coexpressed mouse TRIC-A or TRIC-B with mouse RyR2 in HEK293 cells to examine if after incorporating membrane vesicles from these cells into bilayers, the presence of TRIC affects RyR2 function, and to characterize the permeability and gating properties of the TRIC channels. Importantly, we used no purification techniques or detergents to minimize damage to TRIC and RyR2 proteins. We found that both TRIC-A and TRIC-B altered the gating behavior of RyR2 and its response to cytosolic Ca2+ but that TRIC-A exhibited a greater ability to stimulate the opening of RyR2. Fusing membrane vesicles containing TRIC-A or TRIC-B into bilayers caused the appearance of rapidly gating current fluctuations of multiple amplitudes. The reversal potentials of bilayers fused with high numbers of vesicles containing TRIC-A or TRIC-B revealed both Cl- and K+ fluxes, suggesting that TRIC channels are relatively non-selective ion channels. Our results indicate that the physiological roles of TRIC-A and TRIC-B may include direct, complementary regulation of RyR2 gating in addition to the provision of counter-ion currents of both cations and anions.
Collapse
Affiliation(s)
- Jianshu Hu
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Elisa Venturi
- Department of Pharmacology, University of Oxford, Oxford, UK
| | | | - Takashi Murayama
- Department of Cellular and Molecular Pharmacology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Miyuki Nishi
- Department of Biological Chemistry, Graduate School and Faculty of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Graduate School and Faculty of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | | |
Collapse
|
2
|
Tian S, Zhong X, Wang H, Wei J, Guo W, Wang R, Paul Estillore J, Napolitano C, Duff HH, Ilhan E, Knight LM, Lloyd MS, Roberts JD, Priori SG, Chen SRW. RyR2 C-terminal truncating variants identified in patients with arrhythmic phenotypes exert a dominant negative effect through formation of wildtype-truncation heteromers. Biochem J 2023; 480:1379-1395. [PMID: 37492947 DOI: 10.1042/bcj20230254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/19/2023] [Accepted: 07/25/2023] [Indexed: 07/27/2023]
Abstract
Gain-of-function missense variants in the cardiac ryanodine receptor (RyR2) are linked to catecholaminergic polymorphic ventricular tachycardia (CPVT), whereas RyR2 loss-of-function missense variants cause Ca2+ release deficiency syndrome (CRDS). Recently, truncating variants in RyR2 have also been associated with ventricular arrhythmias (VAs) and sudden cardiac death. However, there are limited insights into the potential clinical relevance and in vitro functional impact of RyR2 truncating variants. We performed genetic screening of patients presenting with syncope, VAs, or unexplained sudden death and in vitro characterization of the expression and function of RyR2 truncating variants in HEK293 cells. We identified two previously unknown RyR2 truncating variants (Y4591Ter and R4663Ter) and one splice site variant predicted to result in a frameshift and premature termination (N4717 + 15Ter). These 3 new RyR2 truncating variants and a recently reported RyR2 truncating variant, R4790Ter, were generated and functionally characterized in vitro. Immunoprecipitation and immunoblotting analyses showed that all 4 RyR2 truncating variants formed heteromers with the RyR2-wildtype (WT) protein. Each of these C-terminal RyR2 truncations was non-functional and suppressed [3H]ryanodine binding to RyR2-WT and RyR2-WT mediated store overload induced spontaneous Ca2+ release activity in HEK293 cells. The expression of these RyR2 truncating variants in HEK293 cells was markedly reduced compared with that of the full-length RyR2 WT protein. Our data indicate that C-terminal RyR2 truncating variants are non-functional and can exert a dominant negative impact on the function of the RyR2 WT protein through formation of heteromeric WT/truncation complex.
Collapse
Affiliation(s)
- Shanshan Tian
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Xiaowei Zhong
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Hui Wang
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Jinhong Wei
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
- School of Medicine, Northwest University, Xi'an 710069, China
| | - Wenting Guo
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ruiwu Wang
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - John Paul Estillore
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Carlo Napolitano
- European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands
- Division of Cardiology and Molecular Cardiology, IRCCS Maugeri Foundation-University of Pavia, 27100 Pavia, Italy
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Henry H Duff
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Erkan Ilhan
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Linda M Knight
- Children's Healthcare of Atlanta Cardiology, Atlanta, Georgia, U.S.A
| | - Michael S Lloyd
- Emory University School of Medicine, Atlanta, Georgia, U.S.A
| | - Jason D Roberts
- Population Health Research Institute, McMaster University, and Hamilton Health Sciences, Hamilton, Ontario, Canada
| | - Silvia G Priori
- European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands
- Division of Cardiology and Molecular Cardiology, IRCCS Maugeri Foundation-University of Pavia, 27100 Pavia, Italy
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
- Molecular Cardiology Laboratory, Centro de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain
| | - S R Wayne Chen
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| |
Collapse
|
3
|
Tambeaux A, Aguilar-Sánchez Y, Santiago DJ, Mascitti M, DiNovo KM, Mejía-Alvarez R, Fill M, Wayne Chen SR, Ramos-Franco J. Ligand sensitivity of type-1 inositol 1,4,5-trisphosphate receptor is enhanced by the D2594K mutation. Pflugers Arch 2023; 475:569-581. [PMID: 36881190 PMCID: PMC10105685 DOI: 10.1007/s00424-023-02796-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/06/2023] [Accepted: 02/12/2023] [Indexed: 03/08/2023]
Abstract
Inositol 1,4,5-trisphosphate receptor (IP3R) and ryanodine receptor (RyR) are homologous cation channels that mediate release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR) and thereby are involved in many physiological processes. In previous studies, we determined that when the D2594 residue, located at or near the gate of the IP3R type 1, was replaced by lysine (D2594K), a gain of function was obtained. This mutant phenotype was characterized by increased IP3 sensitivity. We hypothesized the IP3R1-D2594 determines the ligand sensitivity of the channel by electrostatically affecting the stability of the closed and open states. To test this possibility, the relationship between the D2594 site and IP3R1 regulation by IP3, cytosolic, and luminal Ca2+ was determined at the cellular, subcellular, and single-channel levels using fluorescence Ca2+ imaging and single-channel reconstitution. We found that in cells, D2594K mutation enhances the IP3 ligand sensitivity. Single-channel IP3R1 studies revealed that the conductance of IP3R1-WT and -D2594K channels is similar. However, IP3R1-D2594K channels exhibit higher IP3 sensitivity, with substantially greater efficacy. In addition, like its wild type (WT) counterpart, IP3R1-D2594K showed a bell-shape cytosolic Ca2+-dependency, but D2594K had greater activity at each tested cytosolic free Ca2+ concentration. The IP3R1-D2594K also had altered luminal Ca2+ sensitivity. Unlike IP3R1-WT, D2594K channel activity did not decrease at low luminal Ca2+ levels. Taken together, our functional studies indicate that the substitution of a negatively charged residue by a positive one at the channels' pore cytosolic exit affects the channel's gating behavior thereby explaining the enhanced ligand-channel's sensitivity.
Collapse
Affiliation(s)
- Allison Tambeaux
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL, USA
| | - Yuriana Aguilar-Sánchez
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL, USA.,Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Demetrio J Santiago
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL, USA.,Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | | | - Karyn M DiNovo
- Department of Physiology, Midwestern University, Downers Grove, IL, USA
| | | | - Michael Fill
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL, USA
| | - S R Wayne Chen
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL, USA.,Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Josefina Ramos-Franco
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL, USA.
| |
Collapse
|
4
|
Mustaly-Kalimi S, Gallegos W, Marr RA, Gilman-Sachs A, Peterson DA, Sekler I, Stutzmann GE. Protein mishandling and impaired lysosomal proteolysis generated through calcium dysregulation in Alzheimer's disease. Proc Natl Acad Sci U S A 2022; 119:e2211999119. [PMID: 36442130 PMCID: PMC9894236 DOI: 10.1073/pnas.2211999119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/27/2022] [Indexed: 11/29/2022] Open
Abstract
Impairments in neural lysosomal- and autophagic-mediated degradation of cellular debris contribute to neuritic dystrophy and synaptic loss. While these are well-characterized features of neurodegenerative disorders such as Alzheimer's disease (AD), the upstream cellular processes driving deficits in pathogenic protein mishandling are less understood. Using a series of fluorescent biosensors and optical imaging in model cells, AD mouse models and human neurons derived from AD patients, we reveal a previously undescribed cellular signaling cascade underlying protein mishandling mediated by intracellular calcium dysregulation, an early component of AD pathogenesis. Increased Ca2+ release via the endoplasmic reticulum (ER)-resident ryanodine receptor (RyR) is associated with reduced expression of the lysosome proton pump vacuolar-ATPase (vATPase) subunits (V1B2 and V0a1), resulting in lysosome deacidification and disrupted proteolytic activity in AD mouse models and human-induced neurons (HiN). As a result of impaired lysosome digestive capacity, mature autophagosomes with hyperphosphorylated tau accumulated in AD murine neurons and AD HiN, exacerbating proteinopathy. Normalizing AD-associated aberrant RyR-Ca2+ signaling with the negative allosteric modulator, dantrolene (Ryanodex), restored vATPase levels, lysosomal acidification and proteolytic activity, and autophagic clearance of intracellular protein aggregates in AD neurons. These results highlight that prior to overt AD histopathology or cognitive deficits, aberrant upstream Ca2+ signaling disrupts lysosomal acidification and contributes to pathological accumulation of intracellular protein aggregates. Importantly, this is demonstrated in animal models of AD, and in human iPSC-derived neurons from AD patients. Furthermore, pharmacological suppression of RyR-Ca2+ release rescued proteolytic function, revealing a target for therapeutic intervention that has demonstrated effects in clinically-relevant assays.
Collapse
Affiliation(s)
- Sarah Mustaly-Kalimi
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Wacey Gallegos
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Robert A. Marr
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Alice Gilman-Sachs
- Center for Cancer Cell Biology, Immunology and Infection, Rosalind Franklin University of Medicine and Science, Immunology, and Infection, North Chicago, IL60064
| | - Daniel A. Peterson
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Science and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva84105, Israel
| | - Grace E. Stutzmann
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| |
Collapse
|
5
|
Abstract
Flecainide, a cardiac class 1C blocker of the surface membrane sodium channel (NaV1.5), has also been reported to reduce cardiac ryanodine receptor (RyR2)-mediated sarcoplasmic reticulum (SR) Ca2+ release. It has been introduced as a clinical antiarrhythmic agent for catecholaminergic polymorphic ventricular tachycardia (CPVT), a condition most commonly associated with gain-of-function RyR2 mutations. Current debate concerns both cellular mechanisms of its antiarrhythmic action and molecular mechanisms of its RyR2 actions. At the cellular level, it targets NaV1.5, RyR2, Na+/Ca2+ exchange (NCX), and additional proteins involved in excitation-contraction (EC) coupling and potentially contribute to the CPVT phenotype. This Viewpoint primarily addresses the various direct molecular actions of flecainide on isolated RyR2 channels in artificial lipid bilayers. Such studies demonstrate different, multifarious, flecainide binding sites on RyR2, with voltage-dependent binding in the channel pore or voltage-independent binding at distant peripheral sites. In contrast to its single NaV1.5 pore binding site, flecainide may bind to at least four separate inhibitory sites on RyR2 and one activation site. None of these binding sites have been specifically located in the linear RyR2 sequence or high-resolution structure. Furthermore, it is not clear which of the inhibitory sites contribute to flecainide's reduction of spontaneous Ca2+ release in cellular studies. A confounding observation is that flecainide binding to voltage-dependent inhibition sites reduces cation fluxes in a direction opposite to physiological Ca2+ flow from SR lumen to cytosol. This may suggest that, rather than directly blocking Ca2+ efflux, flecainide can reduce Ca2+ efflux by blocking counter currents through the pore which otherwise limit SR membrane potential change during systolic Ca2+ efflux. In summary, the antiarrhythmic effects of flecainide in CPVT seem to involve multiple components of EC coupling and multiple actions on RyR2. Their clarification may identify novel specific drug targets and facilitate flecainide's clinical utilization in CPVT.
Collapse
Affiliation(s)
| | - Christopher L.-H. Huang
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - James A. Fraser
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Angela F. Dulhunty
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Acton, Australia
| |
Collapse
|
6
|
Ormerod JOM, Ormondroyd E, Li Y, Taylor J, Wei J, Guo W, Wang R, Sarton CNS, McGuire K, Dreau HMP, Taylor JC, Ginks MR, Rajappan K, Chen SRW, Watkins H. Provocation Testing and Therapeutic Response in a Newly Described Channelopathy: RyR2 Calcium Release Deficiency Syndrome. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2022; 15:e003589. [PMID: 34949103 DOI: 10.1161/circgen.121.003589] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND A novel familial arrhythmia syndrome, cardiac ryanodine receptor (RyR2) calcium release deficiency syndrome (CRDS), has recently been described. We evaluated a large and well characterized family to assess provocation testing, risk factor stratification and response to therapy in CRDS. METHODS We present a family with multiple unheralded sudden cardiac deaths and aborted cardiac arrests, primarily in children and young adults, with no clear phenotype on standard clinical testing. RESULTS Genetic analysis, including whole genome sequencing, firmly established that a missense mutation in RYR2, Ala4142Thr, was the underlying cause of disease in the family. Functional study of the variant in a cell model showed RyR2 loss-of-function, indicating that the family was affected by CRDS. EPS (Electrophysiological Study) was undertaken in 9 subjects known to carry the mutation, including a survivor of aborted sudden cardiac death, and the effects of flecainide alone and in combination with metoprolol were tested. There was a clear gradation in inducibility of nonsustained and sustained ventricular arrhythmia between subjects at EPS, with the survivor of aborted sudden cardiac death being the most inducible subject. Administration of flecainide substantially reduced arrhythmia inducibility in this subject and abolished arrhythmia in all others. Finally, the effects of additional metoprolol were tested; it increased inducibility in 4/9 subjects. CONCLUSIONS The Ala4142Thr mutation of RYR2 causes the novel heritable arrhythmia syndrome CRDS, which is characterized by familial sudden death in the absence of prior symptoms or a recognizable phenotype on ambulatory monitoring or exercise stress testing. We increase the experience of a specific EPS protocol in human subjects and show that it is helpful in establishing the clinical status of gene carriers, with potential utility for risk stratification. Our data provide evidence that flecainide is protective in human subjects with CRDS, consistent with the effect previously shown in a mouse model.
Collapse
Affiliation(s)
- Julian O M Ormerod
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (J.O.M.O., E.O., H.W.), University of Oxford, United Kingdom.,Cardiac Rhythm Management Service, Oxford Heart Centre, John Radcliffe Hospital, United Kingdom (J.O.M.O., M.R.G., K.R.)
| | - Elizabeth Ormondroyd
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (J.O.M.O., E.O., H.W.), University of Oxford, United Kingdom
| | - Yanhui Li
- Department of Physiology and Pharmacology, The Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., R.W., S.R.W.C.).,Department of Internal Medicine, Institute of Hypertension, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (Y.L.)
| | - John Taylor
- Oxford Medical Genetics Laboratories, Cardiac Service, Oxford University Hospitals NHS Trust, The Churchill Hospital, United Kingdom (J.T., C.N.S.S., K.M., J.C.T.)
| | - Jinhong Wei
- Department of Physiology and Pharmacology, The Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., R.W., S.R.W.C.)
| | - Wenting Guo
- Department of Physiology and Pharmacology, The Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., R.W., S.R.W.C.)
| | - Ruiwu Wang
- Department of Physiology and Pharmacology, The Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., R.W., S.R.W.C.)
| | - Caroline N S Sarton
- Oxford Medical Genetics Laboratories, Cardiac Service, Oxford University Hospitals NHS Trust, The Churchill Hospital, United Kingdom (J.T., C.N.S.S., K.M., J.C.T.)
| | - Karen McGuire
- Oxford Medical Genetics Laboratories, Cardiac Service, Oxford University Hospitals NHS Trust, The Churchill Hospital, United Kingdom (J.T., C.N.S.S., K.M., J.C.T.)
| | - Helene M P Dreau
- Molecular Diagnostic Centre, Department of Oncology (H.M.P.D.), University of Oxford, United Kingdom
| | - Jenny C Taylor
- Oxford Biomedical Research Centre and Wellcome Centre for Human Genetics (J.C.T., H.W.), University of Oxford, United Kingdom.,Oxford Medical Genetics Laboratories, Cardiac Service, Oxford University Hospitals NHS Trust, The Churchill Hospital, United Kingdom (J.T., C.N.S.S., K.M., J.C.T.)
| | - Matthew R Ginks
- Cardiac Rhythm Management Service, Oxford Heart Centre, John Radcliffe Hospital, United Kingdom (J.O.M.O., M.R.G., K.R.)
| | - Kim Rajappan
- Cardiac Rhythm Management Service, Oxford Heart Centre, John Radcliffe Hospital, United Kingdom (J.O.M.O., M.R.G., K.R.)
| | - S R Wayne Chen
- Department of Physiology and Pharmacology, The Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., R.W., S.R.W.C.)
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (J.O.M.O., E.O., H.W.), University of Oxford, United Kingdom.,Oxford Biomedical Research Centre and Wellcome Centre for Human Genetics (J.C.T., H.W.), University of Oxford, United Kingdom
| |
Collapse
|
7
|
Iaparov B, Baglaeva I, Zahradník I, Zahradníková A. Magnesium Ions Moderate Calcium-Induced Calcium Release in Cardiac Calcium Release Sites by Binding to Ryanodine Receptor Activation and Inhibition Sites. Front Physiol 2022; 12:805956. [PMID: 35145426 PMCID: PMC8821920 DOI: 10.3389/fphys.2021.805956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/21/2021] [Indexed: 12/13/2022] Open
Abstract
Ryanodine receptor channels at calcium release sites of cardiac myocytes operate on the principle of calcium-induced calcium release. In vitro experiments revealed competition of Ca2+ and Mg2+ in the activation of ryanodine receptors (RyRs) as well as inhibition of RyRs by Mg2+. The impact of RyR modulation by Mg2+ on calcium release is not well understood due to the technical limitations of in situ experiments. We turned instead to an in silico model of a calcium release site (CRS), based on a homotetrameric model of RyR gating with kinetic parameters determined from in vitro measurements. We inspected changes in the activity of the CRS model in response to a random opening of one of 20 realistically distributed RyRs, arising from Ca2+/Mg2+ interactions at RyR channels. Calcium release events (CREs) were simulated at a range of Mg2+-binding parameters at near-physiological Mg2+ and ATP concentrations. Facilitation of Mg2+ binding to the RyR activation site inhibited the formation of sparks and slowed down their activation. Impeding Mg-binding to the RyR activation site enhanced spark formation and speeded up their activation. Varying Mg2+ binding to the RyR inhibition site also dramatically affected calcium release events. Facilitation of Mg2+ binding to the RyR inhibition site reduced the amplitude, relative occurrence, and the time-to-end of sparks, and vice versa. The characteristics of CREs correlated dose-dependently with the effective coupling strength between RyRs, defined as a function of RyR vicinity, single-channel calcium current, and Mg-binding parameters of the RyR channels. These findings postulate the role of Mg2+ in calcium release as a negative modulator of the coupling strength among RyRs in a CRS, translating to damping of the positive feedback of the calcium-induced calcium-release mechanism.
Collapse
Affiliation(s)
| | | | | | - Alexandra Zahradníková
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
| |
Collapse
|
8
|
Yuan Q, Dridi H, Clarke OB, Reiken S, Melville Z, Wronska A, Kushnir A, Zalk R, Sittenfeld L, Marks AR. RyR1-related myopathy mutations in ATP and calcium binding sites impair channel regulation. Acta Neuropathol Commun 2021; 9:186. [PMID: 34809703 PMCID: PMC8609856 DOI: 10.1186/s40478-021-01287-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 10/31/2021] [Indexed: 11/10/2022] Open
Abstract
The type 1 ryanodine receptor (RyR1) is an intracellular calcium (Ca2+) release channel on the sarcoplasmic/endoplasmic reticulum that is required for skeletal muscle contraction. RyR1 channel activity is modulated by ligands, including the activators Ca2+ and ATP. Patients with inherited mutations in RyR1 may exhibit muscle weakness as part of a heterogeneous, complex disorder known as RYR1-related myopathy (RYR1-RM) or more recently termed RYR1-related disorders (RYR1-RD). Guided by high-resolution structures of skeletal muscle RyR1, obtained using cryogenic electron microscopy, we introduced mutations into putative Ca2+ and ATP binding sites and studied the function of the resulting mutant channels. These mutations confirmed the functional significance of the Ca2+ and ATP binding sites identified by structural studies based on the effects on channel regulation. Under normal conditions, Ca2+ activates RyR1 at low concentrations (µM) and inhibits it at high concentrations (mM). Mutations in the Ca2+-binding site impaired both activating and inhibitory regulation of the channel, suggesting a single site for both high and low affinity Ca2+-dependent regulation of RyR1 function. Mutation of residues that interact with the adenine ring of ATP abrogated ATP binding to the channel, whereas mutating residues that interact with the triphosphate tail only affected the degree of activation. In addition, patients with mutations at the Ca2+ or ATP binding sites suffer from muscle weakness, therefore impaired RyR1 channel regulation by either Ca2+ or ATP may contribute to the pathophysiology of RYR1-RM in some patients.
Collapse
|
9
|
Wilson AD, Hu J, Sigalas C, Venturi E, Valdivia HH, Valdivia CR, Lei M, Musgaard M, Sitsapesan R. The V2475F CPVT1 mutation yields distinct RyR2 channel populations that differ in their responses to cytosolic Ca 2+ and Mg 2. J Physiol 2021; 599:5179-5201. [PMID: 34676560 DOI: 10.1113/jp281707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 09/30/2021] [Indexed: 11/08/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) is a lethal genetic disease causing arrhythmias and sudden cardiac death in children and young adults and is linked to mutations in the cardiac ryanodine receptor (RyR2). The effects of CPVT1 mutations on RyR2 ion-channel function are often investigated using purified recombinant RyR2 channels homozygous for the mutation. However, CPVT1 patients are heterozygous for the disease, so this approach does not reveal the true changes to RyR2 function across the entire RyR2 population of channels in the heart. We therefore investigated the native cardiac RyR2 single-channel abnormalities in mice heterozygous for the CPVT1 mutation, V2475F(+/-)-RyR2, and applied molecular modelling techniques to investigate the possible structural changes that could initiate any altered function. We observed that increased sensitivity of cardiac V2475F(+/-)-RyR2 channels to both activating and inactivating levels of cytosolic Ca2+ , plus attenuation of Mg2+ inhibition, were the most marked changes. Severity of abnormality was not uniform across all channels, giving rise to multiple sub-populations with differing functional characteristics. For example, 46% of V2475F(+/-)-RyR2 channels exhibited reduced Mg2+ inhibition and 23% were actually activated by Mg2+ . Using homology modelling, we discovered that V2475 is situated at a hinge between two regions of the RyR2 helical domain 1 (HD1). Our model proposes that detrimental functional changes to RyR2 arise because mutation at this critical site reduces the angle between these regions. Our results demonstrate the necessity of characterising the total heterozygous population of CPVT1-mutated channels in order to understand CPVT1 phenotypes in patients. KEY POINTS: RyR2 mutations can cause type-1 catecholaminergic polymorphic ventricular tachycardia (CPVT1), a lethal, autosomal-dominant arrhythmic disease. However, the changes in RyR2 ion-channel function that result from the many different patient mutations are rarely investigated in detail and often only recombinant RyR2, homozygous for the mutation, is studied. As CPVT1 is a heterozygous disease and the tetrameric RyR2 channels expressed in the heart will contain varying numbers of mutated monomers, we have investigated the range of RyR2 single-channel abnormalities found in the hearts of mice heterozygous for the CPVT1 mutation, V2475F(+/-)-RyR2. Specific alterations to ligand regulation of V2475F(+/-)-RyR2 were observed. Multiple sub-populations of channels exhibited varying degrees of abnormality. In particular, an increased sensitivity to activating and inactivating cytosolic [Ca2+ ], and reduced sensitivity to Mg2+ inhibition were evident. Our results provide mechanistic insight into the changes to RyR2 gating that destabilise sarcoplasmic reticulum Ca2+ -release causing life-threatening arrhythmias in V2475F(+/-)-CPVT1 patients.
Collapse
Affiliation(s)
| | - Jianshu Hu
- Department of Pharmacology, University of Oxford, Oxford, UK
| | | | - Elisa Venturi
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Héctor H Valdivia
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, USA
| | - Carmen R Valdivia
- Department of Medicine, Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, USA
| | - Ming Lei
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Maria Musgaard
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | | |
Collapse
|
10
|
Li Y, Wei J, Guo W, Sun B, Estillore JP, Wang R, Yoruk A, Roston TM, Sanatani S, Wilde AAM, Gollob MH, Roberts JD, Tseng ZH, Jensen HK, Chen SRW. Human RyR2 (Ryanodine Receptor 2) Loss-of-Function Mutations: Clinical Phenotypes and In Vitro Characterization. Circ Arrhythm Electrophysiol 2021; 14:e010013. [PMID: 34546788 DOI: 10.1161/circep.121.010013] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- Yanhui Li
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., B.S., J.P.E., R.W., S.R.W.C.).,Department of Internal Medicine, Institute of Hypertension, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China (Y.L.)
| | - Jinhong Wei
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., B.S., J.P.E., R.W., S.R.W.C.)
| | - Wenting Guo
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., B.S., J.P.E., R.W., S.R.W.C.)
| | - Bo Sun
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., B.S., J.P.E., R.W., S.R.W.C.).,Medical School, Kunming University of Science and Technology, China (B.S.)
| | - John Paul Estillore
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., B.S., J.P.E., R.W., S.R.W.C.)
| | - Ruiwu Wang
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., B.S., J.P.E., R.W., S.R.W.C.)
| | - Ayhan Yoruk
- Cardiac Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California, San Francisco (A.Y., Z.H.T.)
| | - Thomas M Roston
- Division of Cardiology, Department of Medicine (T.M.R.), University of British Columbia, Vancouver, Canada
| | - Shubhayan Sanatani
- Child and Family Research Institute, Department of Pediatrics (S.S.), University of British Columbia, Vancouver, Canada
| | - Arthur A M Wilde
- Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam University Medical Centre, location AMC, the Netherlands (A.A.M.W.).,Member of the European Reference Network 'ERN GUARD-Heart' (A.A.M.W.)
| | - Michael H Gollob
- Inherited Arrhythmia and Cardiomyopathy Program, Arrhythmia Service, Division of Cardiology, Toronto General Hospital (M.H.G.), University of Toronto, ON, Canada.,Department of Physiology (M.H.G.), University of Toronto, ON, Canada
| | - Jason D Roberts
- Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada (J.D.R.)
| | - Zian H Tseng
- Cardiac Electrophysiology Section, Division of Cardiology, Department of Medicine, University of California, San Francisco (A.Y., Z.H.T.)
| | - Henrik K Jensen
- Department of Cardiology, Aarhus University Hospital and Department of Clinical Medicine, Health, Aarhus University, Denmark (H.K.J.)
| | - S R Wayne Chen
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, AB, Canada (Y.L., J.W., W.G., B.S., J.P.E., R.W., S.R.W.C.)
| |
Collapse
|
11
|
Woll KA, Van Petegem F. Calcium Release Channels: Structure and Function of IP3 Receptors and Ryanodine Receptors. Physiol Rev 2021; 102:209-268. [PMID: 34280054 DOI: 10.1152/physrev.00033.2020] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca2+-release channels are giant membrane proteins that control the release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. The two members, ryanodine receptors (RyRs) and inositol-1,4,5-trisphosphate Receptors (IP3Rs), are evolutionarily related and are both activated by cytosolic Ca2+. They share a common architecture, but RyRs have evolved additional modules in the cytosolic region. Their massive size allows for the regulation by tens of proteins and small molecules, which can affect the opening and closing of the channels. In addition to Ca2+, other major triggers include IP3 for the IP3Rs, and depolarization of the plasma membrane for a particular RyR subtype. Their size has made them popular targets for study via electron microscopic methods, with current structures culminating near 3Å. The available structures have provided many new mechanistic insights int the binding of auxiliary proteins and small molecules, how these can regulate channel opening, and the mechanisms of disease-associated mutations. They also help scrutinize previously proposed binding sites, as some of these are now incompatible with the structures. Many questions remain around the structural effects of post-translational modifications, additional binding partners, and the higher-order complexes these channels can make in situ. This review summarizes our current knowledge about the structures of Ca2+-release channels and how this informs on their function.
Collapse
Affiliation(s)
- Kellie A Woll
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
12
|
Sun B, Yao J, Ni M, Wei J, Zhong X, Guo W, Zhang L, Wang R, Belke D, Chen YX, Lieve KVV, Broendberg AK, Roston TM, Blankoff I, Kammeraad JA, von Alvensleben JC, Lazarte J, Vallmitjana A, Bohne LJ, Rose RA, Benitez R, Hove-Madsen L, Napolitano C, Hegele RA, Fill M, Sanatani S, Wilde AAM, Roberts JD, Priori SG, Jensen HK, Chen SRW. Cardiac ryanodine receptor calcium release deficiency syndrome. Sci Transl Med 2021; 13:13/579/eaba7287. [PMID: 33536282 DOI: 10.1126/scitranslmed.aba7287] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 12/07/2020] [Indexed: 11/02/2022]
Abstract
Cardiac ryanodine receptor (RyR2) gain-of-function mutations cause catecholaminergic polymorphic ventricular tachycardia, a condition characterized by prominent ventricular ectopy in response to catecholamine stress, which can be reproduced on exercise stress testing (EST). However, reports of sudden cardiac death (SCD) have emerged in EST-negative individuals who have loss-of-function (LOF) RyR2 mutations. The clinical relevance of RyR2 LOF mutations including their pathogenic mechanism, diagnosis, and treatment are all unknowns. Here, we performed clinical and genetic evaluations of individuals who suffered from SCD and harbored an LOF RyR2 mutation. We carried out electrophysiological studies using a programed electrical stimulation protocol consisting of a long-burst, long-pause, and short-coupled (LBLPS) ventricular extra-stimulus. Linkage analysis of RyR2 LOF mutations in six families revealed a combined logarithm of the odds ratio for linkage score of 11.479 for a condition associated with SCD with negative EST. A RyR2 LOF mouse model exhibited no catecholamine-provoked ventricular arrhythmias as in humans but did have substantial cardiac electrophysiological remodeling and an increased propensity for early afterdepolarizations. The LBLPS pacing protocol reliably induced ventricular arrhythmias in mice and humans having RyR2 LOF mutations, whose phenotype is otherwise concealed before SCD. Furthermore, treatment with quinidine and flecainide abolished LBLPS-induced ventricular arrhythmias in model mice. Thus, RyR2 LOF mutations underlie a previously unknown disease entity characterized by SCD with normal EST that we have termed RyR2 Ca2+ release deficiency syndrome (CRDS). Our study provides insights into the mechanism of CRDS, reports a specific CRDS diagnostic test, and identifies potentially efficacious anti-CRDS therapies.
Collapse
Affiliation(s)
- Bo Sun
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada.,Medical School, Kunming University of Science and Technology, Kunming 650504, China
| | - Jinjing Yao
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Mingke Ni
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Jinhong Wei
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Xiaowei Zhong
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Wenting Guo
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Lin Zhang
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Ruiwu Wang
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Darrell Belke
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Yong-Xiang Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Krystien V V Lieve
- Amsterdam University Medical Centre, location AMC, Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam 1105AZ, Netherlands.,European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands
| | - Anders K Broendberg
- Department of Cardiology, Aarhus University Hospital, and Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blv 99, DK-8200 Aarhus N, Denmark
| | - Thomas M Roston
- Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Ivan Blankoff
- C.H.U. Charleroi, Hôpital Civil Marie Curie Chaussée de Bruxelles 140 6042 Charleroi, Belgium
| | - Janneke A Kammeraad
- Department of Pediatric Cardiology, Sophia Children's Hospital, Erasmus University Medical Centre, Doctor Molewaterplein 40, 3015 GD Rotterdam, Netherlands
| | - Johannes C von Alvensleben
- Division of Cardiology, Heart Institute, Children's Hospital Colorado, University of Colorado, Aurora, CO 80045, USA
| | - Julieta Lazarte
- Department of Medicine and Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5B7, Canada
| | - Alexander Vallmitjana
- Department of Automatic Control, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
| | - Loryn J Bohne
- Departments of Cardiac Sciences and Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Robert A Rose
- Departments of Cardiac Sciences and Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Raul Benitez
- Department of Automatic Control, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
| | - Leif Hove-Madsen
- Biomedical Research Institute Barcelona (IIBB-CSIC) and IIB Sant Pau, Hospital de Sant Pau, Barcelona 08025, Spain
| | - Carlo Napolitano
- European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands.,Division of Cardiology and Molecular Cardiology, IRCCS Maugeri Foundation-University of Pavia, 27100 Pavia, Italy.,Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Robert A Hegele
- Department of Medicine and Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5B7, Canada
| | - Michael Fill
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL 60612, USA
| | - Shubhayan Sanatani
- Child and Family Research Institute, Department of Pediatrics, University of British Columbia, Vancouver, BC V6H 3V4, Canada.
| | - Arthur A M Wilde
- Amsterdam University Medical Centre, location AMC, Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam 1105AZ, Netherlands. .,European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands
| | - Jason D Roberts
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, ON N6A 5A5, Canada.
| | - Silvia G Priori
- European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands. .,Division of Cardiology and Molecular Cardiology, IRCCS Maugeri Foundation-University of Pavia, 27100 Pavia, Italy.,Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy.,Molecular Cardiology Laboratory, Centro de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain
| | - Henrik K Jensen
- Department of Cardiology, Aarhus University Hospital, and Department of Clinical Medicine, Health, Aarhus University, Palle Juul-Jensens Blv 99, DK-8200 Aarhus N, Denmark.
| | - S R Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4Z6, Canada. .,Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL 60612, USA
| |
Collapse
|
13
|
Guo W, Wei J, Estillore JP, Zhang L, Wang R, Sun B, Chen SRW. RyR2 disease mutations at the C-terminal domain intersubunit interface alter closed-state stability and channel activation. J Biol Chem 2021; 297:100808. [PMID: 34022226 PMCID: PMC8214192 DOI: 10.1016/j.jbc.2021.100808] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 11/19/2022] Open
Abstract
Ryanodine receptors (RyRs) are ion channels that mediate the release of Ca2+ from the sarcoplasmic reticulum/endoplasmic reticulum, mutations of which are implicated in a number of human diseases. The adjacent C-terminal domains (CTDs) of cardiac RyR (RyR2) interact with each other to form a ring-like tetrameric structure with the intersubunit interface undergoing dynamic changes during channel gating. This mobile CTD intersubunit interface harbors many disease-associated mutations. However, the mechanisms of action of these mutations and the role of CTD in channel function are not well understood. Here, we assessed the impact of CTD disease-associated mutations P4902S, P4902L, E4950K, and G4955E on Ca2+− and caffeine-mediated activation of RyR2. The G4955E mutation dramatically increased both the Ca2+-independent basal activity and Ca2+-dependent activation of [3H]ryanodine binding to RyR2. The P4902S and E4950K mutations also increased Ca2+ activation but had no effect on the basal activity of RyR2. All four disease mutations increased caffeine-mediated activation of RyR2 and reduced the threshold for activation and termination of spontaneous Ca2+ release. G4955D dramatically increased the basal activity of RyR2, whereas G4955K mutation markedly suppressed channel activity. Similarly, substitution of P4902 with a negatively charged residue (P4902D), but not a positively charged residue (P4902K), also dramatically increased the basal activity of RyR2. These data suggest that electrostatic interactions are involved in stabilizing the CTD intersubunit interface and that the G4955E disease mutation disrupts this interface, and thus the stability of the closed state. Our studies shed new insights into the mechanisms of action of RyR2 CTD disease mutations.
Collapse
Affiliation(s)
- Wenting Guo
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Jinhong Wei
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - John Paul Estillore
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Lin Zhang
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Ruiwu Wang
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Bo Sun
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada; Medical School, Kunming University of Science and Technology, Kunming, China.
| | - S R Wayne Chen
- Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.
| |
Collapse
|
14
|
Identification of loss-of-function RyR2 mutations associated with idiopathic ventricular fibrillation and sudden death. Biosci Rep 2021; 41:228220. [PMID: 33825858 PMCID: PMC8062958 DOI: 10.1042/bsr20210209] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/24/2021] [Accepted: 04/06/2021] [Indexed: 11/23/2022] Open
Abstract
Mutations in cardiac ryanodine receptor (RyR2) are linked to catecholaminergic polymorphic ventricular tachycardia (CPVT). Most CPVT RyR2 mutations characterized are gain-of-function (GOF), indicating enhanced RyR2 function as a major cause of CPVT. Loss-of-function (LOF) RyR2 mutations have also been identified and are linked to a distinct entity of cardiac arrhythmia termed RyR2 Ca2+ release deficiency syndrome (CRDS). Exercise stress testing (EST) is routinely used to diagnose CPVT, but it is ineffective for CRDS. There is currently no effective diagnostic tool for CRDS in humans. An alternative strategy to assess the risk for CRDS is to directly determine the functional impact of the associated RyR2 mutations. To this end, we have functionally screened 18 RyR2 mutations that are associated with idiopathic ventricular fibrillation (IVF) or sudden death. We found two additional RyR2 LOF mutations E4146K and G4935R. The E4146K mutation markedly suppressed caffeine activation of RyR2 and abolished store overload induced Ca2+ release (SOICR) in human embryonic kidney 293 (HEK293) cells. E4146K also severely reduced cytosolic Ca2+ activation and abolished luminal Ca2+ activation of single RyR2 channels. The G4935R mutation completely abolished caffeine activation of and [3H]ryanodine binding to RyR2. Co-expression studies showed that the G4935R mutation exerted dominant negative impact on the RyR2 wildtype (WT) channel. Interestingly, the RyR2-G4935R mutant carrier had a negative EST, and the E4146K carrier had a family history of sudden death during sleep, which are different from phenotypes of typical CPVT. Thus, our data further support the link between RyR2 LOF and a new entity of cardiac arrhythmias distinct from CPVT.
Collapse
|
15
|
Shauer A, Shor O, Wei J, Elitzur Y, Kucherenko N, Wang R, Chen SRW, Einav Y, Luria D. Novel RyR2 Mutation (G3118R) Is Associated With Autosomal Recessive Ventricular Fibrillation and Sudden Death: Clinical, Functional, and Computational Analysis. J Am Heart Assoc 2021; 10:e017128. [PMID: 33686871 PMCID: PMC8174198 DOI: 10.1161/jaha.120.017128] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background The cardiac ryanodine receptor type 2 (RyR2) is a large homotetramer, located in the sarcoplasmic reticulum (SR), which releases Ca2+ from the SR during systole. The molecular mechanism underlying Ca2+ sensing and gating of the RyR2 channel in health and disease is only partially elucidated. Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT1) is the most prevalent syndrome caused by RyR2 mutations. Methods and Results This study involves investigation of a family with 4 cases of ventricular fibrillation and sudden death and physiological tests in HEK 293 cells and normal mode analysis (NMA) computation. We found 4 clinically affected members who were homozygous for a novel RyR2 mutation, G3118R, whereas their heterozygous relatives are asymptomatic. G3118R is located in the periphery of the protein, far from the mutation hotspot regions. HEK293 cells harboring G3118R mutation inhibited Ca2+ release in response to increasing doses of caffeine, but decreased the termination threshold for store‐overload‐induced Ca2+ release, thus increasing the fractional Ca2+ release in response to increasing extracellular Ca2+. NMA showed that G3118 affects RyR2 tetramer in a dose‐dependent manner, whereas in the model of homozygous mutant RyR2, the highest entropic values are assigned to the pore and the central regions of the protein. Conclusions RyR2 G3118R is related to ventricular fibrillation and sudden death in recessive mode of inheritance and has an effect of gain of function on the protein. Despite a peripheral location, it has an allosteric effect on the stability of central and pore regions in a dose‐effect manner.
Collapse
Affiliation(s)
- Ayelet Shauer
- Heart Institute Hadassah-Hebrew University Medical Center Jerusalem Israel
| | - Oded Shor
- Heart Institute Hadassah-Hebrew University Medical Center Jerusalem Israel
| | - Jinhong Wei
- Department of Physiology and Pharmacology The Libin Cardiovascular Institute of AlbertaUniversity of Calgary Alberta Canada
| | - Yair Elitzur
- Heart Institute Hadassah-Hebrew University Medical Center Jerusalem Israel
| | - Nataly Kucherenko
- Biochemistry and Molecular Biology Tel Aviv University Tel Aviv Israel
| | - Ruiwu Wang
- Department of Physiology and Pharmacology The Libin Cardiovascular Institute of AlbertaUniversity of Calgary Alberta Canada
| | - S R Wayne Chen
- Department of Physiology and Pharmacology The Libin Cardiovascular Institute of AlbertaUniversity of Calgary Alberta Canada
| | - Yulia Einav
- Faculty of Engineering Holon Institute of Technology Holon Israel
| | - David Luria
- Heart Institute Hadassah-Hebrew University Medical Center Jerusalem Israel
| |
Collapse
|
16
|
T lymphocytes from malignant hyperthermia-susceptible mice display aberrations in intracellular calcium signaling and mitochondrial function. Cell Calcium 2020; 93:102325. [PMID: 33310301 DOI: 10.1016/j.ceca.2020.102325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 01/05/2023]
Abstract
Gain-of-function RyR1-p.R163C mutation in ryanodine receptors type 1 (RyR1) deregulates Ca2+ signaling and mitochondrial function in skeletal muscle and causes malignant hyperthermia in humans and mice under triggering conditions. We investigated whether T lymphocytes from heterozygous RyR1-p.R163C knock-in mutant mice (HET T cells) display measurable aberrations in resting cytosolic Ca2+ concentration ([Ca2+]i), Ca2+ release from the store, store-operated Ca2+ entry (SOCE), and mitochondrial inner membrane potential (ΔΨm) compared with T lymphocytes from wild-type mice (WT T cells). We explored whether these variables can be used to distinguish between T cells with normal and altered RyR1 genotype. HET and WT T cells were isolated from spleen and lymph nodes and activated in vitro using phytohemagglutinin P. [Ca2+]i and ΔΨm dynamics were examined using Fura 2 and tetramethylrhodamine methyl ester fluorescent dyes, respectively. Activated HET T cells displayed elevated resting [Ca2+]i, diminished responses to Ca2+ mobilization with thapsigargin, and decreased rate of [Ca2+]i elevation in response to SOCE compared with WT T cells. Pretreatment of HET T cells with ryanodine or dantrolene sodium reduced disparities in the resting [Ca2+]i and ability of thapsigargin to mobilize Ca2+ between HET and WT T cells. While SOCE elicited dissipation of the ΔΨm in WT T cells, it produced ΔΨm hyperpolarization in HET T cells. When used as the classification variable, the amplitude of thapsigargin-induced Ca2+ transient showed the best promise in predicting the presence of RyR1-p.R163C mutation. Other significant variables identified by machine learning analysis were the ratio of resting cytosolic Ca2+ level to the amplitude of thapsigargin-induced Ca2+ transient and an integral of changes in ΔΨm in response to SOCE. Our study demonstrated that gain-of-function mutation in RyR1 significantly affects Ca2+ signaling and mitochondrial fiction in T lymphocytes, which suggests that this mutation may cause altered immune responses in its carrier. Our data link the RyR1-p.R163C mutation, which causes inherited skeletal muscle diseases, to deregulation of Ca2+ signaling and mitochondrial function in immune T cells and establish proof-of-principle for in vitro T cell-based diagnostic assay for hereditary RyR1 hyperfunction.
Collapse
|
17
|
Evans AM. On a Magical Mystery Tour with 8-Bromo-Cyclic ADP-Ribose: From All-or-None Block to Nanojunctions and the Cell-Wide Web. Molecules 2020; 25:E4768. [PMID: 33081414 PMCID: PMC7587525 DOI: 10.3390/molecules25204768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/08/2020] [Indexed: 11/16/2022] Open
Abstract
A plethora of cellular functions are controlled by calcium signals, that are greatly coordinated by calcium release from intracellular stores, the principal component of which is the sarco/endooplasmic reticulum (S/ER). In 1997 it was generally accepted that activation of various G protein-coupled receptors facilitated inositol-1,4,5-trisphosphate (IP3) production, activation of IP3 receptors and thus calcium release from S/ER. Adding to this, it was evident that S/ER resident ryanodine receptors (RyRs) could support two opposing cellular functions by delivering either highly localised calcium signals, such as calcium sparks, or by carrying propagating, global calcium waves. Coincidentally, it was reported that RyRs in mammalian cardiac myocytes might be regulated by a novel calcium mobilising messenger, cyclic adenosine diphosphate-ribose (cADPR), that had recently been discovered by HC Lee in sea urchin eggs. A reputedly selective and competitive cADPR antagonist, 8-bromo-cADPR, had been developed and was made available to us. We used 8-bromo-cADPR to further explore our observation that S/ER calcium release via RyRs could mediate two opposing functions, namely pulmonary artery dilation and constriction, in a manner seemingly independent of IP3Rs or calcium influx pathways. Importantly, the work of others had shown that, unlike skeletal and cardiac muscles, smooth muscles might express all three RyR subtypes. If this were the case in our experimental system and cADPR played a role, then 8-bromo-cADPR would surely block one of the opposing RyR-dependent functions identified, or the other, but certainly not both. The latter seemingly implausible scenario was confirmed. How could this be, do cells hold multiple, segregated SR stores that incorporate different RyR subtypes in receipt of spatially segregated signals carried by cADPR? The pharmacological profile of 8-bromo-cADPR action supported not only this, but also indicated that intracellular calcium signals were delivered across intracellular junctions formed by the S/ER. Not just one, at least two. This article retraces the steps along this journey, from the curious pharmacological profile of 8-bromo-cADPR to the discovery of the cell-wide web, a diverse network of cytoplasmic nanocourses demarcated by S/ER nanojunctions, which direct site-specific calcium flux and may thus coordinate the full panoply of cellular processes.
Collapse
Grants
- 01/A/S/07453 Biotechnology and Biological Sciences Research Council
- WT046374 , WT056423, WT070772, WT074434, WT081195AIA, WT212923, WT093147 Wellcome Trust
- PG/10/95/28657 British Heart Foundation
- FS/03/033/15432, FS/05/050, PG/05/128/19884, RG/12/14/29885, PG/10/95/28657 British Heart Foundation
- RG/12/14/29885 British Heart Foundation
Collapse
Affiliation(s)
- A Mark Evans
- Centre for Discovery Brain Sciences and Cardiovascular Science, Edinburgh Medical School, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| |
Collapse
|
18
|
Bauerová-Hlinková V, Hajdúchová D, Bauer JA. Structure and Function of the Human Ryanodine Receptors and Their Association with Myopathies-Present State, Challenges, and Perspectives. Molecules 2020; 25:molecules25184040. [PMID: 32899693 PMCID: PMC7570887 DOI: 10.3390/molecules25184040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/28/2020] [Accepted: 08/30/2020] [Indexed: 01/28/2023] Open
Abstract
Cardiac arrhythmias are serious, life-threatening diseases associated with the dysregulation of Ca2+ influx into the cytoplasm of cardiomyocytes. This dysregulation often arises from dysfunction of ryanodine receptor 2 (RyR2), the principal Ca2+ release channel. Dysfunction of RyR1, the skeletal muscle isoform, also results in less severe, but also potentially life-threatening syndromes. The RYR2 and RYR1 genes have been found to harbor three main mutation “hot spots”, where mutations change the channel structure, its interdomain interface properties, its interactions with its binding partners, or its dynamics. In all cases, the result is a defective release of Ca2+ ions from the sarcoplasmic reticulum into the myocyte cytoplasm. Here, we provide an overview of the most frequent diseases resulting from mutations to RyR1 and RyR2, briefly review some of the recent experimental structural work on these two molecules, detail some of the computational work describing their dynamics, and summarize the known changes to the structure and function of these receptors with particular emphasis on their N-terminal, central, and channel domains.
Collapse
|
19
|
Guo W, Sun B, Estillore JP, Wang R, Chen SRW. The central domain of cardiac ryanodine receptor governs channel activation, regulation, and stability. J Biol Chem 2020; 295:15622-15635. [PMID: 32878990 DOI: 10.1074/jbc.ra120.013512] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/25/2020] [Indexed: 11/06/2022] Open
Abstract
Structural analyses identified the central domain of ryanodine receptor (RyR) as a transducer converting conformational changes in the cytoplasmic platform to the RyR gate. The central domain is also a regulatory hub encompassing the Ca2+-, ATP-, and caffeine-binding sites. However, the role of the central domain in RyR activation and regulation has yet to be defined. Here, we mutated five residues that form the Ca2+ activation site and 10 residues with negatively charged or oxygen-containing side chains near the Ca2+ activation site. We also generated eight disease-associated mutations within the central domain of RyR2. We determined the effect of these mutations on Ca2+, ATP, and caffeine activation and Mg2+ inhibition of RyR2. Mutating the Ca2+ activation site markedly reduced the sensitivity of RyR2 to Ca2+ and caffeine activation. Unexpectedly, Ca2+ activation site mutation E3848A substantially enhanced the Ca2+-independent basal activity of RyR2, suggesting that E3848A may also affect the stability of the closed state of RyR2. Mutations in the Ca2+ activation site also abolished the effect of ATP/caffeine on the Ca2+-independent basal activity, suggesting that the Ca2+ activation site is also a critical determinant of ATP/caffeine action. Mutating residues with negatively charged or oxygen-containing side chains near the Ca2+ activation site significantly altered Ca2+ and caffeine activation and reduced Mg2+ inhibition. Furthermore, disease-associated RyR2 mutations within the central domain significantly enhanced Ca2+ and caffeine activation and reduced Mg2+ inhibition. Our data demonstrate that the central domain plays an important role in channel activation, channel regulation, and closed state stability.
Collapse
Affiliation(s)
- Wenting Guo
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Bo Sun
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; Medical School, Kunming University of Science and Technology, Kunming, China
| | - John Paul Estillore
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Ruiwu Wang
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - S R Wayne Chen
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; Department of Biochemistry and Molecular Biology, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada.
| |
Collapse
|
20
|
Zhang XH, Morad M. Ca 2+ signaling of human pluripotent stem cells-derived cardiomyocytes as compared to adult mammalian cardiomyocytes. Cell Calcium 2020; 90:102244. [PMID: 32585508 PMCID: PMC7483365 DOI: 10.1016/j.ceca.2020.102244] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/23/2022]
Abstract
Human induced pluripotent stem cells derived cardiomyocytes (hiPSC-CMs) have been extensively used for in vitro modeling of human cardiovascular disease, drug screening and pharmacotherapy, but little rigorous studies have been reported on their biophysical or Ca2+ signaling properties. There is also considerable concern as to the level of their maturity and whether they can serve as reliable models for adult human cardiac myocytes. Ultrastructural difference such as lack of t-tubular network, their polygonal shapes, disorganized sarcomeric myofilament, and their rhythmic automaticity, among others, have been cited as evidence for immaturity of hiPSC-CMs. In this review, we will deal with Ca2+ signaling, its regulation, and its stage of maturity as compared to the mammalian adult cardiomyocytes. We shall summarize the data on functional aspects of Ca2+signaling and its parameters that include: L-type calcium channel (Cav1.2), ICa-induced Ca2+release, CICR, and its parameters, cardiac Na/Ca exchanger (NCX1), the ryanodine receptors (RyR2), sarco-reticular Ca2+pump, SERCA2a/PLB, and the contribution of mitochondrial Ca2+ to hiPSC-CMs excitation-contraction (EC)-coupling as compared with adult mammalian cardiomyocytes. The comparative studies suggest that qualitatively hiPSC-CMs have similar Ca2+signaling properties as those of adult cardiomyocytes, but quantitative differences do exist. This review, we hope, will allow the readers to judge for themselves to what extent Ca2+signaling of hiPSC-CMs represents the adult form of this signaling pathway, and whether these cells can be used as good models of human cardiomyocytes.
Collapse
Affiliation(s)
- Xiao-Hua Zhang
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, Clemson University, Charleston SC, United States
| | - Martin Morad
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, Clemson University, Charleston SC, United States.
| |
Collapse
|
21
|
Skogestad J, Aronsen JM, Tovsrud N, Wanichawan P, Hougen K, Stokke MK, Carlson CR, Sjaastad I, Sejersted OM, Swift F. Coupling of the Na+/K+-ATPase to Ankyrin B controls Na+/Ca2+ exchanger activity in cardiomyocytes. Cardiovasc Res 2020; 116:78-90. [PMID: 30949686 DOI: 10.1093/cvr/cvz087] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/22/2019] [Accepted: 04/03/2019] [Indexed: 01/28/2023] Open
Abstract
AIMS Ankyrin B (AnkB) is an adaptor protein that assembles Na+/K+-ATPase (NKA) and Na+/Ca2+ exchanger (NCX) in the AnkB macromolecular complex. Loss-of-function mutations in AnkB cause the AnkB syndrome in humans, characterized by ventricular arrhythmias and sudden cardiac death. It is unclear to what extent NKA binding to AnkB allows regulation of local Na+ and Ca2+ domains and hence NCX activity. METHODS AND RESULTS To investigate the role of NKA binding to AnkB in cardiomyocytes, we synthesized a disruptor peptide (MAB peptide) and its AnkB binding ability was verified by pulldown experiments. As opposed to control, the correlation between NKA and NCX currents was abolished in adult rat ventricular myocytes dialyzed with MAB peptide, as well as in cardiomyocytes from AnkB+/- mice. Disruption of NKA from AnkB (with MAB peptide) increased NCX-sensed cytosolic Na+ concentration, reduced Ca2+ extrusion through NCX, and increased frequency of Ca2+ sparks and Ca2+ waves without concomitant increase in Ca2+ transient amplitude or SR Ca2+ load, suggesting an effect in local Ca2+ domains. Selective inhibition of the NKAα2 isoform abolished both the correlation between NKA and NCX currents and the increased rate of Ca2+ sparks and waves following NKA/AnkB disruption, suggesting that an AnkB/NKAα2/NCX domain controls Ca2+ fluxes in cardiomyocytes. CONCLUSION NKA binding to AnkB allows ion regulation in a local domain, and acute disruption of the NKA/AnkB interaction using disruptor peptides lead to increased rate of Ca2+ sparks and waves. The functional effects were mediated through the NKAα2 isoform. Disruption of the AnkB/NKA/NCX domain could be an important pathophysiological mechanism in the AnkB syndrome.
Collapse
Affiliation(s)
- Jonas Skogestad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Nils Tovsrud
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Pimthanya Wanichawan
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Karina Hougen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Mathis Korseberg Stokke
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Cathrine Rein Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ole Mathias Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Fredrik Swift
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Ullevål, N-0407 Oslo, Norway.,KG Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway.,Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
| |
Collapse
|
22
|
Bartolucci C, Passini E, Hyttinen J, Paci M, Severi S. Simulation of the Effects of Extracellular Calcium Changes Leads to a Novel Computational Model of Human Ventricular Action Potential With a Revised Calcium Handling. Front Physiol 2020; 11:314. [PMID: 32351400 PMCID: PMC7174690 DOI: 10.3389/fphys.2020.00314] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/19/2020] [Indexed: 01/13/2023] Open
Abstract
The importance of electrolyte concentrations for cardiac function is well established. Electrolyte variations can lead to arrhythmias onset, due to their important role in the action potential (AP) genesis and in maintaining cell homeostasis. However, most of the human AP computer models available in literature were developed with constant electrolyte concentrations, and fail to simulate physiological changes induced by electrolyte variations. This is especially true for Ca2+, even in the O'Hara-Rudy model (ORd), one of the most widely used models in cardiac electrophysiology. Therefore, the present work develops a new human ventricular model (BPS2020), based on ORd, able to simulate the inverse dependence of AP duration (APD) on extracellular Ca2+ concentration ([Ca2+]o), and APD rate dependence at 4 mM extracellular K+. The main changes needed with respect to ORd are: (i) an increased sensitivity of L-type Ca2+ current inactivation to [Ca2+]o; (ii) a single compartment description of the sarcoplasmic reticulum; iii) the replacement of Ca2+ release. BPS2020 is able to simulate the physiological APD-[Ca2+]o relationship, while also retaining the well-reproduced properties of ORd (APD rate dependence, restitution, accommodation and current block effects). We also used BPS2020 to generate an experimentally-calibrated population of models to investigate: (i) the occurrence of repolarization abnormalities in response to hERG current block; (ii) the rate adaptation variability; (iii) the occurrence of alternans and delayed after-depolarizations at fast pacing. Our results indicate that we successfully developed an improved version of ORd, which can be used to investigate electrophysiological changes and pro-arrhythmic abnormalities induced by electrolyte variations and current block at multiple rates and at the population level.
Collapse
Affiliation(s)
- Chiara Bartolucci
- Computational Physiopathology Unit, Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy
| | - Elisa Passini
- Computational Physiopathology Unit, Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy
- Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Jari Hyttinen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Michelangelo Paci
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Stefano Severi
- Computational Physiopathology Unit, Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Cesena, Italy
| |
Collapse
|
23
|
Yamaguchi N. Molecular Insights into Calcium Dependent Regulation of Ryanodine Receptor Calcium Release Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1131:321-336. [DOI: 10.1007/978-3-030-12457-1_13] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
24
|
Badone B, Ronchi C, Kotta MC, Sala L, Ghidoni A, Crotti L, Zaza A. Calmodulinopathy: Functional Effects of CALM Mutations and Their Relationship With Clinical Phenotypes. Front Cardiovasc Med 2018; 5:176. [PMID: 30619883 PMCID: PMC6297375 DOI: 10.3389/fcvm.2018.00176] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/22/2018] [Indexed: 12/16/2022] Open
Abstract
In spite of the widespread role of calmodulin (CaM) in cellular signaling, CaM mutations lead specifically to cardiac manifestations, characterized by remarkable electrical instability and a high incidence of sudden death at young age. Penetrance of the mutations is surprisingly high, thus postulating a high degree of functional dominance. According to the clinical patterns, arrhythmogenesis in CaM mutations can be attributed, in the majority of cases, to either prolonged repolarization (as in long-QT syndrome, LQTS phenotype), or to instability of the intracellular Ca2+ store (as in catecholamine-induced tachycardias, CPVT phenotype). This review discusses how mutations affect CaM signaling function and how this may relate to the distinct arrhythmia phenotypes/mechanisms observed in patients; this involves mechanistic interpretation of negative dominance and mutation-specific CaM-target interactions. Knowledge of the mechanisms involved may allow critical approach to clinical manifestations and aid in the development of therapeutic strategies for "calmodulinopathies," a recently identified nosological entity.
Collapse
Affiliation(s)
- Beatrice Badone
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Carlotta Ronchi
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Maria-Christina Kotta
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan, Italy
| | - Luca Sala
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan, Italy
| | - Alice Ghidoni
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan, Italy
| | - Lia Crotti
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan, Italy
- Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
- Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Istituto Auxologico Italiano, IRCCS, Milan, Italy
| | - Antonio Zaza
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| |
Collapse
|
25
|
Influence of Lipid Mimetics on Gating of Ryanodine Receptor. Structure 2018; 26:1303-1313.e4. [DOI: 10.1016/j.str.2018.06.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 03/27/2018] [Accepted: 06/27/2018] [Indexed: 11/17/2022]
|
26
|
Brusich DJ, Spring AM, James TD, Yeates CJ, Helms TH, Frank CA. Drosophila CaV2 channels harboring human migraine mutations cause synapse hyperexcitability that can be suppressed by inhibition of a Ca2+ store release pathway. PLoS Genet 2018; 14:e1007577. [PMID: 30080864 PMCID: PMC6095605 DOI: 10.1371/journal.pgen.1007577] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/16/2018] [Accepted: 07/20/2018] [Indexed: 11/28/2022] Open
Abstract
Gain-of-function mutations in the human CaV2.1 gene CACNA1A cause familial hemiplegic migraine type 1 (FHM1). To characterize cellular problems potentially triggered by CaV2.1 gains of function, we engineered mutations encoding FHM1 amino-acid substitutions S218L (SL) and R192Q (RQ) into transgenes of Drosophila melanogaster CaV2/cacophony. We expressed the transgenes pan-neuronally. Phenotypes were mild for RQ-expressing animals. By contrast, single mutant SL- and complex allele RQ,SL-expressing animals showed overt phenotypes, including sharply decreased viability. By electrophysiology, SL- and RQ,SL-expressing neuromuscular junctions (NMJs) exhibited enhanced evoked discharges, supernumerary discharges, and an increase in the amplitudes and frequencies of spontaneous events. Some spontaneous events were gigantic (10-40 mV), multi-quantal events. Gigantic spontaneous events were eliminated by application of TTX-or by lowered or chelated Ca2+-suggesting that gigantic events were elicited by spontaneous nerve firing. A follow-up genetic approach revealed that some neuronal hyperexcitability phenotypes were reversed after knockdown or mutation of Drosophila homologs of phospholipase Cβ (PLCβ), IP3 receptor, or ryanodine receptor (RyR)-all factors known to mediate Ca2+ release from intracellular stores. Pharmacological inhibitors of intracellular Ca2+ store release produced similar effects. Interestingly, however, the decreased viability phenotype was not reversed by genetic impairment of intracellular Ca2+ release factors. On a cellular level, our data suggest inhibition of signaling that triggers intracellular Ca2+ release could counteract hyperexcitability induced by gains of CaV2.1 function.
Collapse
Affiliation(s)
- Douglas J. Brusich
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
| | - Ashlyn M. Spring
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA, United States of America
| | - Thomas D. James
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, United States of America
| | - Catherine J. Yeates
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, United States of America
| | - Timothy H. Helms
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
| | - C. Andrew Frank
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA, United States of America
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, United States of America
| |
Collapse
|
27
|
Laver DR. Regulation of the RyR channel gating by Ca 2+ and Mg 2. Biophys Rev 2018; 10:1087-1095. [PMID: 29926426 PMCID: PMC6082316 DOI: 10.1007/s12551-018-0433-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/06/2018] [Indexed: 12/21/2022] Open
Abstract
Ryanodine receptors (RyRs) are the Ca2+ release channels in the sarcoplasmic reticulum in striated muscle which play an important role in excitation-contraction coupling and cardiac pacemaking. Single channel recordings have revealed a wealth of information about ligand regulation of RyRs from mammalian skeletal and cardiac muscle (RyR1 and RyR2, respectively). RyR subunit has a Ca2+ activation site located in the luminal and cytoplasmic domains of the RyR. These sites synergistically feed into a common gating mechanism for channel activation by luminal and cytoplasmic Ca2+. RyRs also possess two inhibitory sites in their cytoplasmic domains with Ca2+ affinities of the order of 1 μM and 1 mM. Magnesium competes with Ca2+ at these sites to inhibit RyRs and this plays an important role in modulating their Ca2+-dependent activity in muscle. This review focuses on how these sites lead to RyR modulation by Ca2+ and Mg2+ and how these mechanisms control Ca2+ release in excitation-contraction coupling and cardiac pacemaking.
Collapse
Affiliation(s)
- Derek R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia.
| |
Collapse
|
28
|
Guo W, Zhu C, Yin Z, Wang Q, Sun M, Cao H, Greaser ML. Splicing Factor RBM20 Regulates Transcriptional Network of Titin Associated and Calcium Handling Genes in The Heart. Int J Biol Sci 2018; 14:369-380. [PMID: 29725258 PMCID: PMC5930469 DOI: 10.7150/ijbs.24117] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/27/2018] [Indexed: 01/28/2023] Open
Abstract
RNA binding motif 20 (RBM20) regulates pre-mRNA splicing of over thirty genes, among which titin is a major target. With RBM20 expression, titin expresses a larger isoform at fetal stage to a smaller isoform at adult resulting from alternative splicing, while, without RBM20, titin expresses exclusively a larger isoform throughout all ages. In addition to splicing regulation, it is unknown whether RBM20 also regulates gene expression. In this study, we employed Rbm20 knockout rats to investigate gene expression profile using Affymetrix expression array. We compared wild type to Rbm20 knockout at day1, 20 and 49. Bioinformatics analysis showed RBM20 regulates fewer genes expression at younger age and more at older age and commonly expressed genes have the same trends. GSEA indicated up-regulated genes are associated with heart failure. We examined titin binding partners. All titin direct binding partners are up-regulated and their increased expression is associated with dilated cardiomyopathy. Particularly, we found that genes involving calcium handling and muscle contraction are changed by RBM20. Intracellular calcium level measurement with individual cardiomyocytes further confirmed that changes of these proteins impact calcium handling. Selected genes from titin binding partners and calcium handling were validated with QPCR and western blotting. These data demonstrate that RBM20 regulates gene splicing as well as gene expression. Altered gene expression by RBM20 influences protein-protein interaction, calcium releasing and thus muscle contraction. Our results first reported gene expression impacted by RBM20 with heart maturation, and provided new insights into the role of RBM20 in the progression of heart failure.
Collapse
Affiliation(s)
- Wei Guo
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
| | - Chaoqun Zhu
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
| | - Zhiyong Yin
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Department of Cardiology, Xi Jing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Qiurong Wang
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
| | - Mingming Sun
- Animal Science, University of Wyoming, Laramie, WY 82071, USA.,Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, Laramie, WY 82071, USA
| | - Huojun Cao
- Iowa Institute for Oral Health Research, College of Dentistry.,Craniofacial Anomalies Research Center, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - Marion L Greaser
- Animal Science, University of Wisconsin-Madison, Madison, WI 53705, USA
| |
Collapse
|
29
|
Liu Y, Wei J, Wong King Yuen SM, Sun B, Tang Y, Wang R, Van Petegem F, Chen SRW. CPVT-associated cardiac ryanodine receptor mutation G357S with reduced penetrance impairs Ca2+ release termination and diminishes protein expression. PLoS One 2017; 12:e0184177. [PMID: 28961276 PMCID: PMC5621672 DOI: 10.1371/journal.pone.0184177] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 08/18/2017] [Indexed: 11/18/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is one of the most lethal inherited cardiac arrhythmias mostly linked to cardiac ryanodine receptor (RyR2) mutations with high disease penetrance. Interestingly, a novel RyR2 mutation G357S discovered in a large family of more than 1400 individuals has reduced penetrance. The molecular basis for the incomplete disease penetrance in this family is unknown. To gain insights into the variable disease expression in this family, we determined the impact of the G357S mutation on RyR2 function and expression. We assessed spontaneous Ca2+ release in HEK293 cells expressing RyR2 wildtype and the G357S mutant during store Ca2+ overload, also known as store overload induced Ca2+ release (SOICR). We found that the G357S mutation reduced the percentage of RyR2-expressing cells that showed SOICR. However, in cells that displayed SOICR, G357S reduced the thresholds for the activation and termination of SOICR. Furthermore, G357S decreased the thermal stability of the N-terminal domain of RyR2, and markedly reduced the protein expression of the full-length RyR2. On the other hand, the G357S mutation did not alter the Ca2+ activation of [3H]ryanodine binding or the Ca2+ induced release of Ca2+ from the intracellular stores in HEK293 cells. These data indicate that the CPVT-associated G357S mutation enhances the arrhythmogenic SOICR and reduces RyR2 protein expression, which may be attributable to the incomplete penetrance of CPVT in this family.
Collapse
Affiliation(s)
- Yingjie Liu
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Jinhong Wei
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Siobhan M Wong King Yuen
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada
| | - Bo Sun
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Yijun Tang
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Ruiwu Wang
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada
| | - S R Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
30
|
Sárközi S, Komáromi I, Jóna I, Almássy J. Lanthanides Report Calcium Sensor in the Vestibule of Ryanodine Receptor. Biophys J 2017; 112:2127-2137. [PMID: 28538150 DOI: 10.1016/j.bpj.2017.03.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 03/11/2017] [Accepted: 03/23/2017] [Indexed: 02/07/2023] Open
Abstract
Ca2+ regulates ryanodine receptor's (RyR) activity through an activating and an inhibiting Ca2+-binding site located on the cytoplasmic side of the RyR channel. Their altered sensitivity plays an important role in the pathology of malignant hyperthermia and heart failure. We used lanthanide ions (Ln3+) as probes to investigate the Ca2+ sensors of RyR, because they specifically bind to Ca2+-binding proteins and they are impermeable to the channel. Eu3+'s and Sm3+'s action was tested on single RyR1 channels reconstituted into planar lipid bilayers. When the activating binding site was saturated by 50 μM Ca2+, Ln3+ potently inhibited RyR's open probability (Kd Eu3+ = 167 ± 5 nM and Kd Sm3+ = 63 ± 3 nM), but in nominally 0 [Ca2+], low [Eu3+] activated the channel. These results suggest that Ln3+ acts as an agonist of both Ca2+-binding sites. More importantly, the voltage-dependent characteristics of Ln3+'s action led to the conclusion that the activating Ca2+ binding site is located within the electrical field of the channel (in the vestibule). This idea was tested by applying the pore blocker toxin maurocalcine on the cytoplasmic side of RyR. These experiments showed that RyR lost reactivity to changing cytosolic [Ca2+] from 50 μM to 100 nM when the toxin occupied the vestibule. These results suggest that maurocalcine mechanically prevented Ca2+ from dissociating from its binding site and support our vestibular Ca2+ sensor-model further.
Collapse
Affiliation(s)
- Sándor Sárközi
- Department of Physiology, Faculty of Medicine, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - István Komáromi
- Division of Clinical Laboratory Science, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - István Jóna
- Department of Physiology, Faculty of Medicine, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Almássy
- Department of Physiology, Faculty of Medicine, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
| |
Collapse
|
31
|
Bongianino R, Denegri M, Mazzanti A, Lodola F, Vollero A, Boncompagni S, Fasciano S, Rizzo G, Mangione D, Barbaro S, Di Fonso A, Napolitano C, Auricchio A, Protasi F, Priori SG. Allele-Specific Silencing of Mutant mRNA Rescues Ultrastructural and Arrhythmic Phenotype in Mice Carriers of the R4496C Mutation in the Ryanodine Receptor Gene ( RYR2). Circ Res 2017; 121:525-536. [PMID: 28620067 DOI: 10.1161/circresaha.117.310882] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 06/07/2017] [Accepted: 06/14/2017] [Indexed: 11/16/2022]
Abstract
RATIONALE Mutations in the cardiac Ryanodine Receptor gene (RYR2) cause dominant catecholaminergic polymorphic ventricular tachycardia (CPVT), a leading cause of sudden death in apparently healthy individuals exposed to emotions or physical exercise. OBJECTIVE We investigated the efficacy of allele-specific silencing by RNA interference to prevent CPVT phenotypic manifestations in our dominant CPVT mice model carriers of the heterozygous mutation R4496C in RYR2. METHODS AND RESULTS We developed an in vitro mRNA and protein-based assays to screen multiple siRNAs for their ability to selectively silence mutant RYR2-R4496C mRNA over the corresponding wild-type allele. For the most performant of these siRNAs (siRYR2-U10), we evaluated the efficacy of an adeno-associated serotype 9 viral vector (AAV9) expressing miRYR2-U10 in correcting RyR2 (Ryanodine Receptor type 2 protein) function after in vivo delivery by intraperitoneal injection in neonatal and adult RyR2R4496C/+ (mice heterozygous for the R4496C mutation in the RyR2) heterozygous CPVT mice. Transcriptional analysis showed that after treatment with miRYR2-U10, the ratio between wild-type and mutant RYR2 mRNA was doubled (from 1:1 to 2:1) confirming the ability of miRYR2-U10 to selectively inhibit RYR2-R4496C mRNA, whereas protein quantification showed that total RyR2 was reduced by 15% in the heart of treated mice. Furthermore, AAV9-miRYR2-U10 effectively (1) reduced isoproterenol-induced delayed afterdepolarizations and triggered activity in infected cells, (2) reduced adrenergically mediated ventricular tachycardia in treated mice, (3) reverted ultrastructural abnormalities of junctional sarcoplasmic reticulum and transverse tubules, and (4) attenuated mitochondrial abnormalities. CONCLUSIONS The study demonstrates that allele-specific silencing with miRYR2-U10 prevents life-threatening arrhythmias in CPVT mice, suggesting that the reduction of mutant RyR2 may be a novel therapeutic approach for CPVT.
Collapse
Affiliation(s)
- Rossana Bongianino
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Marco Denegri
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Andrea Mazzanti
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Francesco Lodola
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Alessandra Vollero
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Simona Boncompagni
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Silvia Fasciano
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Giulia Rizzo
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Damiano Mangione
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Serena Barbaro
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Alessia Di Fonso
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Carlo Napolitano
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Alberto Auricchio
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Feliciano Protasi
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.)
| | - Silvia G Priori
- From the Molecular Cardiology, IRCCS Istituti Clinici Scientifici Maugeri, Pavia, Italy (R.B., M.D., A.M., F.L., A.V., S.F., G.R., D.M., S.B., C.N., S.G.P.); Department of Molecular Medicine, University of Pavia, Italy (R.B., A.M., S.F., S.G.P.); CeSI-Met - Center for Research on Ageing and Translational Medicine & DNICS - Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio, Chieti, Italy (S.B., A.D.F.); CeSI-Met - Center for Research on Ageing and Translational Medicine and DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio, Chieti, Italy (F.P.); Telethon Institute of Genetics and Medicine, Naples, Italy (A.A.); and Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy (A.A.).
| |
Collapse
|
32
|
Gaburjakova M, Gaburjakova J. Insight towards the identification of cytosolic Ca 2+ -binding sites in ryanodine receptors from skeletal and cardiac muscle. Acta Physiol (Oxf) 2017; 219:757-767. [PMID: 27543850 DOI: 10.1111/apha.12772] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 07/13/2016] [Accepted: 08/12/2016] [Indexed: 11/30/2022]
Abstract
Ca2+ plays a critical role in several processes involved in skeletal and cardiac muscle contraction. One key step in cardiac excitation-contraction (E-C) coupling is the activation of the cardiac ryanodine receptor (RYR2) by cytosolic Ca2+ elevations. Although this process is not critical for skeletal E-C coupling, the activation and inhibition of the skeletal ryanodine receptor (RYR1) seem to be important for overall muscle function. The RYR1 and RYR2 channels fall within the large category of Ca2+ -binding proteins that harbour highly selective Ca2+ -binding sites to receive and translate the various Ca2+ signals into specific functional responses. However, little is known about the precise localization of these sites within the cytosolic assembly of both RYR isoforms, although several experimental lines of evidence have highlighted their EF-hand nature. EF-hand proteins share a common helix-loop-helix structural motif with highly conserved residues involved in Ca2+ coordination. The first step in predicting EF-hand positive regions is to compare the primary protein structure with the EF-hand motif by employing available bioinformatics tools. Although this simple method narrows down search regions, it does not provide solid evidence regarding which regions bind Ca2+ in both RYR isoforms. In this review, we seek to highlight the key findings and experimental approaches that should strengthen our future efforts to identify the cytosolic Ca2+ -binding sites responsible for activation and inhibition in the RYR1 channel, as much less work has been conducted on the RYR2 channel.
Collapse
Affiliation(s)
- M. Gaburjakova
- Institute of Molecular Physiology and Genetics; Slovak Academy of Sciences; Bratislava Slovak Republic
| | - J. Gaburjakova
- Institute of Molecular Physiology and Genetics; Slovak Academy of Sciences; Bratislava Slovak Republic
| |
Collapse
|
33
|
Van Petegem F. Ligand binding to Ryanodine Receptors revealed through cryo-electron microscopy. Cell Calcium 2017; 61:50-52. [DOI: 10.1016/j.ceca.2016.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 10/29/2016] [Indexed: 10/20/2022]
|
34
|
Fameli N, Evans AM, van Breemen C. Tissue Specificity: The Role of Organellar Membrane Nanojunctions in Smooth Muscle Ca2+ Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:321-342. [DOI: 10.1007/978-3-319-57732-6_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
|
35
|
des Georges A, Clarke OB, Zalk R, Yuan Q, Condon KJ, Grassucci RA, Hendrickson WA, Marks AR, Frank J. Structural Basis for Gating and Activation of RyR1. Cell 2016; 167:145-157.e17. [PMID: 27662087 DOI: 10.1016/j.cell.2016.08.075] [Citation(s) in RCA: 256] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/08/2016] [Accepted: 08/30/2016] [Indexed: 10/21/2022]
Abstract
The type-1 ryanodine receptor (RyR1) is an intracellular calcium (Ca(2+)) release channel required for skeletal muscle contraction. Here, we present cryo-EM reconstructions of RyR1 in multiple functional states revealing the structural basis of channel gating and ligand-dependent activation. Binding sites for the channel activators Ca(2+), ATP, and caffeine were identified at interdomain interfaces of the C-terminal domain. Either ATP or Ca(2+) alone induces conformational changes in the cytoplasmic assembly ("priming"), without pore dilation. In contrast, in the presence of all three activating ligands, high-resolution reconstructions of open and closed states of RyR1 were obtained from the same sample, enabling analyses of conformational changes associated with gating. Gating involves global conformational changes in the cytosolic assembly accompanied by local changes in the transmembrane domain, which include bending of the S6 transmembrane segment and consequent pore dilation, displacement, and deformation of the S4-S5 linker and conformational changes in the pseudo-voltage-sensor domain.
Collapse
Affiliation(s)
- Amédée des Georges
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Oliver B Clarke
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Ran Zalk
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Qi Yuan
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Kendall J Condon
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Robert A Grassucci
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Wayne A Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Department of Medicine, Columbia University, New York, NY 10032, USA; Wu Center for Molecular Cardiology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biological Sciences, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
36
|
Evans AM. Nanojunctions of the Sarcoplasmic Reticulum Deliver Site- and Function-Specific Calcium Signaling in Vascular Smooth Muscles. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:1-47. [PMID: 28212795 DOI: 10.1016/bs.apha.2016.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Vasoactive agents may induce myocyte contraction, dilation, and the switch from a contractile to a migratory-proliferative phenotype(s), which requires changes in gene expression. These processes are directed, in part, by Ca2+ signals, but how different Ca2+ signals are generated to select each function is enigmatic. We have previously proposed that the strategic positioning of Ca2+ pumps and release channels at membrane-membrane junctions of the sarcoplasmic reticulum (SR) demarcates cytoplasmic nanodomains, within which site- and function-specific Ca2+ signals arise. This chapter will describe how nanojunctions of the SR may: (1) define cytoplasmic nanospaces about the plasma membrane, mitochondria, contractile myofilaments, lysosomes, and the nucleus; (2) provide for functional segregation by restricting passive diffusion and by coordinating active ion transfer within a given nanospace via resident Ca2+ pumps and release channels; (3) select for contraction, relaxation, and/or changes in gene expression; and (4) facilitate the switch in myocyte phenotype through junctional reorganization. This should serve to highlight the need for further exploration of cellular nanojunctions and the mechanisms by which they operate, that will undoubtedly open up new therapeutic horizons.
Collapse
Affiliation(s)
- A M Evans
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom.
| |
Collapse
|
37
|
Sun B, Guo W, Tian X, Yao J, Zhang L, Wang R, Chen SRW. The Cytoplasmic Region of Inner Helix S6 Is an Important Determinant of Cardiac Ryanodine Receptor Channel Gating. J Biol Chem 2016; 291:26024-26034. [PMID: 27789712 DOI: 10.1074/jbc.m116.758821] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/18/2016] [Indexed: 11/06/2022] Open
Abstract
The ryanodine receptor (RyR) channel pore is formed by four S6 inner helices, with its intracellular gate located at the S6 helix bundle crossing region. The cytoplasmic region of the extended S6 helix is held by the U motif of the central domain and is thought to control the opening and closing of the S6 helix bundle. However, the functional significance of the S6 cytoplasmic region in channel gating is unknown. Here we assessed the role of the S6 cytoplasmic region in the function of cardiac RyR (RyR2) via structure-guided site-directed mutagenesis. We mutated each residue in the S6 cytoplasmic region of the mouse RyR2 (4876QQEQVKEDM4884) and characterized their functional impact. We found that mutations Q4876A, V4880A, K4881A, and M4884A, located mainly on one side of the S6 helix that faces the U motif, enhanced basal channel activity and the sensitivity to Ca2+ or caffeine activation, whereas mutations Q4877A, E4878A, Q4879A, and D4883A, located largely on the opposite side of S6, suppressed channel activity. Furthermore, V4880A, a cardiac arrhythmia-associated mutation, markedly enhanced the frequency of spontaneous openings and the sensitivity to cytosolic and luminal Ca2+ activation of single RyR2 channels. V4880A also increased the propensity and reduced the threshold for arrhythmogenic spontaneous Ca2+ release in HEK293 cells. Collectively, our data suggest that interactions between the cytoplasmic region of S6 and the U motif of RyR2 are important for stabilizing the closed state of the channel. Mutations in the S6/U motif domain interface likely destabilize the closed state of RyR2, resulting in enhanced basal channel activity and sensitivity to activation and increased propensity for spontaneous Ca2+ release and cardiac arrhythmias.
Collapse
Affiliation(s)
- Bo Sun
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Wenting Guo
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Xixi Tian
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Jinjing Yao
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Lin Zhang
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ruiwu Wang
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - S R Wayne Chen
- From the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| |
Collapse
|
38
|
Xiao Z, Guo W, Sun B, Hunt DJ, Wei J, Liu Y, Wang Y, Wang R, Jones PP, Back TG, Chen SRW. Enhanced Cytosolic Ca2+ Activation Underlies a Common Defect of Central Domain Cardiac Ryanodine Receptor Mutations Linked to Arrhythmias. J Biol Chem 2016; 291:24528-24537. [PMID: 27733687 DOI: 10.1074/jbc.m116.756528] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/02/2016] [Indexed: 01/21/2023] Open
Abstract
Recent three-dimensional structural studies reveal that the central domain of ryanodine receptor (RyR) serves as a transducer that converts long-range conformational changes into the gating of the channel pore. Interestingly, the central domain encompasses one of the mutation hotspots (corresponding to amino acid residues 3778-4201) that contains a number of cardiac RyR (RyR2) mutations associated with catecholaminergic polymorphic ventricular tachycardia (CPVT) and atrial fibrillation (AF). However, the functional consequences of these central domain RyR2 mutations are not well understood. To gain insights into the impact of the mutation and the role of the central domain in channel function, we generated and characterized eight disease-associated RyR2 mutations in the central domain. We found that all eight central domain RyR2 mutations enhanced the Ca2+-dependent activation of [3H]ryanodine binding, increased cytosolic Ca2+-induced fractional Ca2+ release, and reduced the activation and termination thresholds for spontaneous Ca2+ release in HEK293 cells. We also showed that racemic carvedilol and the non-beta-blocking carvedilol enantiomer, (R)-carvedilol, suppressed spontaneous Ca2+ oscillations in HEK293 cells expressing the central domain RyR2 mutations associated with CPVT and AF. These data indicate that the central domain is an important determinant of cytosolic Ca2+ activation of RyR2. These results also suggest that altered cytosolic Ca2+ activation of RyR2 represents a common defect of RyR2 mutations associated with CPVT and AF, which could potentially be suppressed by carvedilol or (R)-carvedilol.
Collapse
Affiliation(s)
- Zhichao Xiao
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Wenting Guo
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Bo Sun
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Donald J Hunt
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Jinhong Wei
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Yingjie Liu
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Yundi Wang
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ruiwu Wang
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Peter P Jones
- the Department of Physiology, Otago School of Medical Sciences and HeartOtago, University of Otago, Dunedin 9054, New Zealand, and
| | - Thomas G Back
- the Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - S R Wayne Chen
- From the the Department of Physiology and Pharmacology, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4N1, Canada,.
| |
Collapse
|
39
|
Peng W, Shen H, Wu J, Guo W, Pan X, Wang R, Chen SRW, Yan N. Structural basis for the gating mechanism of the type 2 ryanodine receptor RyR2. Science 2016; 354:science.aah5324. [PMID: 27708056 DOI: 10.1126/science.aah5324] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/14/2016] [Indexed: 01/10/2023]
Abstract
RyR2 is a high-conductance intracellular calcium (Ca2+) channel that controls the release of Ca2+ from the sarco(endo)plasmic reticulum of a variety of cells. Here, we report the structures of RyR2 from porcine heart in both the open and closed states at near-atomic resolutions determined using single-particle electron cryomicroscopy. Structural comparison reveals a breathing motion of the overall cytoplasmic region resulted from the interdomain movements of amino-terminal domains (NTDs), Helical domains, and Handle domains, whereas almost no intradomain shifts are observed in these armadillo repeats-containing domains. Outward rotations of the Central domains, which integrate the conformational changes of the cytoplasmic region, lead to the dilation of the cytoplasmic gate through coupled motions. Our structural and mutational characterizations provide important insights into the gating and disease mechanism of RyRs.
Collapse
Affiliation(s)
- Wei Peng
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
| | - Huaizong Shen
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Jianping Wu
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Wenting Guo
- The Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada, T2N 4N1
| | - Xiaojing Pan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
| | - Ruiwu Wang
- The Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada, T2N 4N1
| | - S R Wayne Chen
- The Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada, T2N 4N1.
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. .,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| |
Collapse
|
40
|
From contraction to gene expression: nanojunctions of the sarco/endoplasmic reticulum deliver site- and function-specific calcium signals. SCIENCE CHINA-LIFE SCIENCES 2016; 59:749-63. [PMID: 27376531 DOI: 10.1007/s11427-016-5071-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/07/2016] [Indexed: 10/21/2022]
Abstract
Calcium signals determine, for example, smooth muscle contraction and changes in gene expression. How calcium signals select for these processes is enigmatic. We build on the "panjunctional sarcoplasmic reticulum" hypothesis, describing our view that different calcium pumps and release channels, with different kinetics and affinities for calcium, are strategically positioned within nanojunctions of the SR and help demarcate their respective cytoplasmic nanodomains. SERCA2b and RyR1 are preferentially targeted to the sarcoplasmic reticulum (SR) proximal to the plasma membrane (PM), i.e., to the superficial buffer barrier formed by PM-SR nanojunctions, and support vasodilation. In marked contrast, SERCA2a may be entirely restricted to the deep, perinuclear SR and may supply calcium to this sub-compartment in support of vasoconstriction. RyR3 is also preferentially targeted to the perinuclear SR, where its clusters associate with lysosome-SR nanojunctions. The distribution of RyR2 is more widespread and extends from this region to the wider cell. Therefore, perinuclear RyR3s most likely support the initiation of global calcium waves at L-SR junctions, which subsequently propagate by calcium-induced calcium release via RyR2 in order to elicit contraction. Data also suggest that unique SERCA and RyR are preferentially targeted to invaginations of the nuclear membrane. Site- and function-specific calcium signals may thus arise to modulate stimulus-response coupling and transcriptional cascades.
Collapse
|
41
|
Yuchi Z, Van Petegem F. Ryanodine receptors under the magnifying lens: Insights and limitations of cryo-electron microscopy and X-ray crystallography studies. Cell Calcium 2016; 59:209-27. [DOI: 10.1016/j.ceca.2016.04.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/08/2016] [Accepted: 04/09/2016] [Indexed: 10/21/2022]
|
42
|
Petrovič P, Valent I, Cocherová E, Pavelková J, Zahradníková A. Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes. ACTA ACUST UNITED AC 2016; 145:489-511. [PMID: 26009544 PMCID: PMC4442793 DOI: 10.1085/jgp.201411281] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Calcium waves can form and propagate at low frequencies of spontaneous calcium sparks if the calcium dependence of spark frequency is sufficiently steep, or the number of open RyRs is sufficiently large. The role of cardiac ryanodine receptor (RyR) gating in the initiation and propagation of calcium waves was investigated using a mathematical model comprising a stochastic description of RyR gating and a deterministic description of calcium diffusion and sequestration. We used a one-dimensional array of equidistantly spaced RyR clusters, representing the confocal scanning line, to simulate the formation of calcium sparks. Our model provided an excellent description of the calcium dependence of the frequency of diastolic calcium sparks and of the increased tendency for the production of calcium waves after a decrease in cytosolic calcium buffering. We developed a hypothesis relating changes in the propensity to form calcium waves to changes of RyR gating and tested it by simulation. With a realistic RyR gating model, increased ability of RyR to be activated by Ca2+ strongly increased the propensity for generation of calcium waves at low (0.05–0.1-µM) calcium concentrations but only slightly at high (0.2–0.4-µM) calcium concentrations. Changes in RyR gating altered calcium wave formation by changing the calcium sensitivity of spontaneous calcium spark activation and/or the average number of open RyRs in spontaneous calcium sparks. Gating changes that did not affect RyR activation by Ca2+ had only a weak effect on the propensity to form calcium waves, even if they strongly increased calcium spark frequency. Calcium waves induced by modulating the properties of the RyR activation site could be suppressed by inhibiting the spontaneous opening of the RyR. These data can explain the increased tendency for production of calcium waves under conditions when RyR gating is altered in cardiac diseases.
Collapse
Affiliation(s)
- Pavol Petrovič
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovak Republic
| | - Ivan Valent
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovak Republic Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic
| | - Elena Cocherová
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic Institute of Electronics and Photonics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, 812 19 Bratislava, Slovak Republic
| | - Jana Pavelková
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic
| | - Alexandra Zahradníková
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic
| |
Collapse
|
43
|
Guo W, Sun B, Xiao Z, Liu Y, Wang Y, Zhang L, Wang R, Chen SRW. The EF-hand Ca2+ Binding Domain Is Not Required for Cytosolic Ca2+ Activation of the Cardiac Ryanodine Receptor. J Biol Chem 2015; 291:2150-60. [PMID: 26663082 DOI: 10.1074/jbc.m115.693325] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Indexed: 11/06/2022] Open
Abstract
Activation of the cardiac ryanodine receptor (RyR2) by elevating cytosolic Ca(2+) is a central step in the process of Ca(2+)-induced Ca(2+) release, but the molecular basis of RyR2 activation by cytosolic Ca(2+) is poorly defined. It has been proposed recently that the putative Ca(2+) binding domain encompassing a pair of EF-hand motifs (EF1 and EF2) in the skeletal muscle ryanodine receptor (RyR1) functions as a Ca(2+) sensor that regulates the gating of RyR1. Although the role of the EF-hand domain in RyR1 function has been studied extensively, little is known about the functional significance of the corresponding EF-hand domain in RyR2. Here we investigate the effect of mutations in the EF-hand motifs on the Ca(2+) activation of RyR2. We found that mutations in the EF-hand motifs or deletion of the entire EF-hand domain did not affect the Ca(2+)-dependent activation of [(3)H]ryanodine binding or the cytosolic Ca(2+) activation of RyR2. On the other hand, deletion of the EF-hand domain markedly suppressed the luminal Ca(2+) activation of RyR2 and spontaneous Ca(2+) release in HEK293 cells during store Ca(2+) overload or store overload-induced Ca(2+) release (SOICR). Furthermore, mutations in the EF2 motif, but not EF1 motif, of RyR2 raised the threshold for SOICR termination, whereas deletion of the EF-hand domain of RyR2 increased both the activation and termination thresholds for SOICR. These results indicate that, although the EF-hand domain is not required for RyR2 activation by cytosolic Ca(2+), it plays an important role in luminal Ca(2+) activation and SOICR.
Collapse
Affiliation(s)
- Wenting Guo
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Bo Sun
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Zhichao Xiao
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Yingjie Liu
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Yundi Wang
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Lin Zhang
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Ruiwu Wang
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - S R Wayne Chen
- From the Libin Cardiovascular Institute of Alberta, Departments of Physiology and Pharmacology and Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| |
Collapse
|
44
|
Xiao Z, Guo W, Yuen SMWK, Wang R, Zhang L, Van Petegem F, Chen SRW. The H29D Mutation Does Not Enhance Cytosolic Ca2+ Activation of the Cardiac Ryanodine Receptor. PLoS One 2015; 10:e0139058. [PMID: 26405799 PMCID: PMC4583508 DOI: 10.1371/journal.pone.0139058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/07/2015] [Indexed: 11/25/2022] Open
Abstract
The N-terminal domain of the cardiac ryanodine receptor (RyR2) harbors a large number of naturally occurring mutations that are associated with stress-induced ventricular tachyarrhythmia and sudden death. Nearly all these disease-associated N-terminal mutations are located at domain interfaces or buried within domains. Mutations at these locations would alter domain-domain interactions or the stability/folding of domains. Recently, a novel RyR2 mutation H29D associated with ventricular arrhythmia at rest was found to enhance the activation of single RyR2 channels by diastolic levels of cytosolic Ca2+. Unlike other N-terminal disease-associated mutations, the H29D mutation is located on the surface of the N-terminal domain. It is unclear how this surface-exposed H29D mutation that does not appear to interact with other parts of the RyR2 structure could alter the intrinsic properties of the channel. Here we carried out detailed functional characterization of the RyR2-H29D mutant at the molecular and cellular levels. We found that the H29D mutation has no effect on the basal level or the Ca2+ dependent activation of [3H]ryanodine binding to RyR2, the cytosolic Ca2+ activation of single RyR2 channels, or the cytosolic Ca2+- or caffeine-induced Ca2+ release in HEK293 cells. In addition, the H29D mutation does not alter the propensity for spontaneous Ca2+ release or the thresholds for Ca2+ release activation or termination. Furthermore, the H29D mutation does not have significant impact on the thermal stability of the N-terminal region (residues 1–547) of RyR2. Collectively, our data show that the H29D mutation exerts little or no effect on the function of RyR2 or on the folding stability of the N-terminal region. Thus, our results provide no evidence that the H29D mutation enhances the cytosolic Ca2+ activation of RyR2.
Collapse
Affiliation(s)
- Zhichao Xiao
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Wenting Guo
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Siobhan M. Wong King Yuen
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
| | - Ruiwu Wang
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Lin Zhang
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, Canada V6T 1Z3
| | - S. R. Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Libin Cardiovascular Institute of Alberta, Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- * E-mail:
| |
Collapse
|
45
|
Søndergaard MT, Tian X, Liu Y, Wang R, Chazin WJ, Chen SRW, Overgaard MT. Arrhythmogenic Calmodulin Mutations Affect the Activation and Termination of Cardiac Ryanodine Receptor-mediated Ca2+ Release. J Biol Chem 2015; 290:26151-62. [PMID: 26309258 DOI: 10.1074/jbc.m115.676627] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Indexed: 11/06/2022] Open
Abstract
The intracellular Ca(2+) sensor calmodulin (CaM) regulates the cardiac Ca(2+) release channel/ryanodine receptor 2 (RyR2), and mutations in CaM cause arrhythmias such as catecholaminergic polymorphic ventricular tachycardia (CPVT) and long QT syndrome. Here, we investigated the effect of CaM mutations causing CPVT (N53I), long QT syndrome (D95V and D129G), or both (CaM N97S) on RyR2-mediated Ca(2+) release. All mutations increased Ca(2+) release and rendered RyR2 more susceptible to store overload-induced Ca(2+) release (SOICR) by lowering the threshold of store Ca(2+) content at which SOICR occurred and the threshold at which SOICR terminated. To obtain mechanistic insights, we investigated the Ca(2+) binding of the N- and C-terminal domains (N- and C-domain) of CaM in the presence of a peptide corresponding to the CaM-binding domain of RyR2. The N53I mutation decreased the affinity of Ca(2+) binding to the N-domain of CaM, relative to CaM WT, but did not affect the C-domain. Conversely, mutations N97S, D95V, and D129G had little or no effect on Ca(2+) binding to the N-domain but markedly decreased the affinity of the C-domain for Ca(2+). These results suggest that mutations D95V, N97S, and D129G alter the interaction between CaM and the CaMBD and thus RyR2 regulation. Because the N53I mutation minimally affected Ca(2+) binding to the C-domain, it must cause aberrant regulation via a different mechanism. These results support aberrant RyR2 regulation as the disease mechanism for CPVT associated with CaM mutations and shows that CaM mutations not associated with CPVT can also affect RyR2. A model for the CaM-RyR2 interaction, where the Ca(2+)-saturated C-domain is constitutively bound to RyR2 and the N-domain senses increases in Ca(2+) concentration, is proposed.
Collapse
Affiliation(s)
- Mads T Søndergaard
- From the Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark, the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Xixi Tian
- the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Yingjie Liu
- the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Ruiwu Wang
- the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Walter J Chazin
- the Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235
| | - S R Wayne Chen
- the Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Michael T Overgaard
- From the Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark,
| |
Collapse
|
46
|
Van Petegem F. Ryanodine Receptors: Allosteric Ion Channel Giants. J Mol Biol 2015; 427:31-53. [DOI: 10.1016/j.jmb.2014.08.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/02/2014] [Accepted: 08/05/2014] [Indexed: 01/27/2023]
|
47
|
Gomez AC, Yamaguchi N. Two regions of the ryanodine receptor calcium channel are involved in Ca(2+)-dependent inactivation. Biochemistry 2014; 53:1373-9. [PMID: 24521037 PMCID: PMC3985739 DOI: 10.1021/bi401586h] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Skeletal (RyR1) and cardiac muscle (RyR2) isoforms of ryanodine receptor calcium channels are inhibited by millimollar Ca(2+), but the affinity of RyR2 for inhibitory Ca(2+) is ~10 times lower than that of RyR1. Previous studies demonstrated that the C-terminal quarter of RyR has critical domain(s) for Ca(2+) inactivation. To obtain further insights into the molecular basis of regulation of RyRs by Ca(2+), we constructed and expressed 18 RyR1-RyR2 chimeras in HEK293 cells and determined the Ca(2+) activation and inactivation affinities of these channels using the [(3)H]ryanodine binding assay. Replacing two distinct regions of RyR1 with corresponding RyR2 sequences reduced the affinity for Ca(2+) inactivation. The first region (RyR2 amino acids 4020-4250) contains two EF-hand Ca(2+) binding motifs (EF1, amino acids 4036-4047; EF2, amino acids 4071-4082), and the second region includes the putative second transmembrane segment (S2). A RyR1-backbone chimera containing only EF2 from RyR2 had a modest (not significant) change in Ca(2+) inactivation, whereas another chimera channel carrying only EF1 from RyR2 had a significantly reduced level of Ca(2+) inactivation. The results suggest that EF1 is a more critical determinant for RyR inactivation by Ca(2+). In addition, activities of the chimera carrying RyR2 EF-hands were suppressed at 10-100 μM Ca(2+), and the suppression was relieved by 1 mM Mg(2+). The same effects have been observed with wild-type RyR2. A mutant RyR1 carrying both regions replaced with RyR2 sequences (amino acids 4020-4250 and 4560-4618) showed a Ca(2+) inactivation affinity comparable to that of RyR2, indicating that these regions are sufficient to confer RyR2-type Ca(2+)-dependent inactivation on RyR1.
Collapse
Affiliation(s)
- Angela C Gomez
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina , and Cardiac Signaling Center, University of South Carolina , Medical University of South Carolina , and Clemson University , Charleston, South Carolina 29425, United States
| | | |
Collapse
|
48
|
Liu B, Ho HT, Velez-Cortes F, Lou Q, Valdivia CR, Knollmann BC, Valdivia HH, Gyorke S. Genetic ablation of ryanodine receptor 2 phosphorylation at Ser-2808 aggravates Ca(2+)-dependent cardiomyopathy by exacerbating diastolic Ca2+ release. J Physiol 2014; 592:1957-73. [PMID: 24445321 DOI: 10.1113/jphysiol.2013.264689] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Phosphorylation of the cardiac ryanodine receptor (RyR2) by protein kinase A (PKA) at Ser-2808 is suggested to mediate the physiological 'fight or flight' response and contribute to heart failure by rendering the sarcoplasmic reticulum (SR) leaky for Ca(2+). In the present study, we examined the potential role of RyR2 phosphorylation at Ser-2808 in the progression of Ca(2+)-dependent cardiomyopathy (CCM) by using mice genetically modified to feature elevated SR Ca(2+) leak while expressing RyR2s that cannot be phosphorylated at this site (S2808A). Surprisingly, rather than alleviating the disease phenotype, constitutive dephosphorylation of Ser-2808 aggravated CCM as manifested by shortened survival, deteriorated in vivo cardiac function, exacerbated SR Ca(2+) leak and mitochondrial injury. Notably, the deteriorations of cardiac function, myocyte Ca(2+) handling, and mitochondria integrity were consistently worse in mice with heterozygous ablation of Ser-2808 than in mice with complete ablation. Wild-type (WT) and CCM myocytes expressing unmutated RyR2s exhibited a high level of baseline phosphorylation at Ser-2808. Exposure of these CCM cells to protein phosphatase 1 caused a transitory increase in Ca(2+) leak attributable to partial dephosphorylation of RyR2 tetramers at Ser-2808 from more fully phosphorylated state. Thus, exacerbated Ca(2+) leak through partially dephosphorylated RyR2s accounts for the prevalence of the disease phenotype in the heterozygous S2808A CCM mice. These results do not support the importance of RyR2 hyperphosphorylation in Ca(2+)-dependent heart disease, and rather suggest roles for the opposite process, the RyR2 dephosphorylation at this residue in physiological and pathophysiological Ca(2+) signalling.
Collapse
Affiliation(s)
- Bin Liu
- Department of Physiology and Cell Biology, 507 Davis Heart & Lung Research Institute (office), 473 W. 12th Avenue, Columbus, OH 43210, USA.
| | | | | | | | | | | | | | | |
Collapse
|
49
|
The ryanodine receptor store-sensing gate controls Ca2+ waves and Ca2+-triggered arrhythmias. Nat Med 2014; 20:184-92. [PMID: 24441828 DOI: 10.1038/nm.3440] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 12/03/2013] [Indexed: 12/12/2022]
Abstract
Spontaneous Ca(2+) release from intracellular stores is important for various physiological and pathological processes. In cardiac muscle cells, spontaneous store overload-induced Ca(2+) release (SOICR) can result in Ca(2+) waves, a major cause of ventricular tachyarrhythmias (VTs) and sudden death. The molecular mechanism underlying SOICR has been a mystery for decades. Here we show that a point mutation, E4872A, in the helix bundle crossing region (the proposed gate) of the cardiac ryanodine receptor (RyR2) completely abolishes luminal, but not cytosolic, Ca(2+) activation of RyR2. The introduction of metal-binding histidines at this site converts RyR2 into a luminal Ni(2+)-gated channel. Mouse hearts harboring a heterozygous RyR2 mutation at this site (E4872Q) are resistant to SOICR and are completely protected against Ca(2+)-triggered VTs. These data show that the RyR2 gate directly senses luminal (store) Ca(2+), explaining the regulation of RyR2 by luminal Ca(2+), the initiation of Ca(2+) waves and Ca(2+)-triggered arrhythmias. This newly identified store-sensing gate structure is conserved in all RyR and inositol 1,4,5-trisphosphate receptor isoforms.
Collapse
|
50
|
McKay PB, Griswold CK. A comparative study indicates both positive and purifying selection within ryanodine receptor (RyR) genes, as well as correlated evolution. ACTA ACUST UNITED AC 2013; 321:151-63. [DOI: 10.1002/jez.1845] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 09/15/2013] [Accepted: 10/28/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Patrick B. McKay
- Department of Integrative Biology; University of Guelph; Ontario Canada
| | | |
Collapse
|