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Gandon-Renard M, Val-Blasco A, Oughlis C, Gerbaud P, Lefebvre F, Gomez S, Journé C, Courilleau D, Mercier-Nomé F, Pereira L, Benitah JP, Gómez AM, Mercadier JJ. Dual effect of cardiac FKBP12.6 overexpression on excitation-contraction coupling and the incidence of ventricular arrhythmia depending on its expression level. J Mol Cell Cardiol 2024; 188:15-29. [PMID: 38224852 DOI: 10.1016/j.yjmcc.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/27/2023] [Accepted: 01/11/2024] [Indexed: 01/17/2024]
Abstract
FKBP12.6, a binding protein to the immunosuppressant FK506, which also binds the ryanodine receptor (RyR2) in the heart, has been proposed to regulate RyR2 function and to have antiarrhythmic properties. However, the level of FKBP12.6 expression in normal hearts remains elusive and some controversies still persist regarding its effects, both in basal conditions and during β-adrenergic stimulation. We quantified FKBP12.6 in the left ventricles (LV) of WT (wild-type) mice and in two novel transgenic models expressing distinct levels of FKBP12.6, using a custom-made specific anti-FKBP12.6 antibody and a recombinant protein. FKBP12.6 level in WT LV was very low (0.16 ± 0.02 nmol/g of LV), indicating that <15% RyR2 monomers are bound to the protein. Mice with 14.1 ± 0.2 nmol of FKBP12.6 per g of LV (TG1) had mild cardiac hypertrophy and normal function and were protected against epinephrine/caffeine-evoked arrhythmias. The ventricular myocytes showed higher [Ca2+]i transient amplitudes than WT myocytes and normal SR-Ca2+ load, while fewer myocytes showed Ca2+ sparks. TG1 cardiomyocytes responded to 50 nM Isoproterenol increasing these [Ca2+]i parameters and producing RyR2-Ser2808 phosphorylation. Mice with more than twice the TG1 FKBP12.6 value (TG2) showed marked cardiac hypertrophy with calcineurin activation and more arrhythmias than WT mice during β-adrenergic stimulation, challenging the protective potential of high FKBP12.6. RyR2R420Q CPVT mice overexpressing FKBP12.6 showed fewer proarrhythmic events and decreased incidence and duration of stress-induced bidirectional ventricular tachycardia. Our study, therefore, quantifies for the first time endogenous FKBP12.6 in the mouse heart, questioning its physiological relevance, at least at rest due its low level. By contrast, our work demonstrates that with caution FKBP12.6 remains an interesting target for the development of new antiarrhythmic therapies.
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Affiliation(s)
- Marine Gandon-Renard
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Almudena Val-Blasco
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Célia Oughlis
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Pascale Gerbaud
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Florence Lefebvre
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Susana Gomez
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Clément Journé
- Fédération de Recherche en Imagerie Multimodale (FRIM), Université Paris Cité, 75018 Paris, France
| | | | - Françoise Mercier-Nomé
- UMS-IPSIT, Université Paris-Saclay, 91400 Orsay, France; Inflammation, Microbiome and Immunosurveillance, Inserm UMR-996, Université Paris-Saclay, 92140 Clamart, France
| | - Laetitia Pereira
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Jean-Pierre Benitah
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Ana Maria Gómez
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France.
| | - Jean-Jacques Mercadier
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France; Université Paris Cité, Paris, France.
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2
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Waddell HMM, Mereacre V, Alvarado FJ, Munro ML. Clustering properties of the cardiac ryanodine receptor in health and heart failure. J Mol Cell Cardiol 2023; 185:38-49. [PMID: 37890552 PMCID: PMC10717225 DOI: 10.1016/j.yjmcc.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/09/2023] [Accepted: 10/24/2023] [Indexed: 10/29/2023]
Abstract
The cardiac ryanodine receptor (RyR2) is an intracellular Ca2+ release channel vital for the function of the heart. Physiologically, RyR2 is triggered to release Ca2+ from the sarcoplasmic reticulum (SR) which enables cardiac contraction; however, spontaneous Ca2+ leak from RyR2 has been implicated in the pathophysiology of heart failure (HF). RyR2 channels have been well documented to assemble into clusters within the SR membrane, with the organisation of RyR2 clusters recently gaining interest as a mechanism by which the occurrence of pathological Ca2+ leak is regulated, including in HF. In this review, we explain the terminology relating to key nanoscale RyR2 clustering properties as both single clusters and functionally grouped Ca2+ release units, with a focus on the advancements in super-resolution imaging approaches which have enabled the detailed study of cluster organisation. Further, we discuss proposed mechanisms for modulating RyR2 channel organisation and the debate regarding the potential impact of cluster organisation on Ca2+ leak activity. Finally, recent experimental evidence investigating the nanoscale remodelling and functional alterations of RyR2 clusters in HF is discussed with consideration of the clinical implications.
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Affiliation(s)
- Helen M M Waddell
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Valeria Mereacre
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Francisco J Alvarado
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Michelle L Munro
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
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3
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Svensson B, Nitu FR, Rebbeck RT, McGurran LM, Oda T, Thomas DD, Bers DM, Cornea RL. Molecular Mechanism of a FRET Biosensor for the Cardiac Ryanodine Receptor Pathologically Leaky State. Int J Mol Sci 2023; 24:12547. [PMID: 37628726 PMCID: PMC10454150 DOI: 10.3390/ijms241612547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Ca2+ leak from cardiomyocyte sarcoplasmic reticulum (SR) via hyperactive resting cardiac ryanodine receptor channels (RyR2) is pro-arrhythmic. An exogenous peptide (DPc10) binding promotes leaky RyR2 in cardiomyocytes and reports on that endogenous state. Conversely, calmodulin (CaM) binding inhibits RyR2 leak and low CaM affinity is diagnostic of leaky RyR2. These observations have led to designing a FRET biosensor for drug discovery targeting RyR2. We used FRET to clarify the molecular mechanism driving the DPc10-CaM interdependence when binding RyR2 in SR vesicles. We used donor-FKBP12.6 (D-FKBP) to resolve RyR2 binding of acceptor-CaM (A-CaM). In low nanomolar Ca2+, DPc10 decreased both FRETmax (under saturating [A-CaM]) and the CaM/RyR2 binding affinity. In micromolar Ca2+, DPc10 decreased FRETmax without affecting CaM/RyR2 binding affinity. This correlates with the analysis of fluorescence-lifetime-detected FRET, indicating that DPc10 lowers occupancy of the RyR2 CaM-binding sites in nanomolar (not micromolar) Ca2+ and lengthens D-FKBP/A-CaM distances independent of [Ca2+]. To observe DPc10/RyR2 binding, we used acceptor-DPc10 (A-DPc10). CaM weakens A-DPc10/RyR2 binding, with this effect being larger in micromolar versus nanomolar Ca2+. Moreover, A-DPc10/RyR2 binding is cooperative in a CaM- and FKBP-dependent manner, suggesting that both endogenous modulators promote concerted structural changes between RyR2 protomers for channel regulation. Aided by the analysis of cryo-EM structures, these insights inform further development of the DPc10-CaM paradigm for therapeutic discovery targeting RyR2.
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Affiliation(s)
- Bengt Svensson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (B.S.); (R.T.R.); (L.M.M.)
| | - Florentin R. Nitu
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (B.S.); (R.T.R.); (L.M.M.)
| | - Robyn T. Rebbeck
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (B.S.); (R.T.R.); (L.M.M.)
| | - Lindsey M. McGurran
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (B.S.); (R.T.R.); (L.M.M.)
| | - Tetsuro Oda
- Department of Pharmacology, University of California, Davis, CA 95616, USA
| | - David D. Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (B.S.); (R.T.R.); (L.M.M.)
| | - Donald M. Bers
- Department of Pharmacology, University of California, Davis, CA 95616, USA
| | - Razvan L. Cornea
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; (B.S.); (R.T.R.); (L.M.M.)
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4
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Walweel K, Beard N, van Helden DF, Laver DR. Dantrolene inhibition of ryanodine channels (RyR2) in artificial lipid bilayers depends on FKBP12.6. J Gen Physiol 2023; 155:e202213277. [PMID: 37279522 PMCID: PMC10244881 DOI: 10.1085/jgp.202213277] [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: 10/10/2022] [Revised: 03/18/2023] [Accepted: 05/22/2023] [Indexed: 06/08/2023] Open
Abstract
Dantrolene is a neutral hydantoin that is clinically used as a skeletal muscle relaxant to prevent overactivation of the skeletal muscle calcium release channel (RyR1) in response to volatile anesthetics. Dantrolene has aroused considerable recent interest as a lead compound for stabilizing calcium release due to overactive cardiac calcium release channels (RyR2) in heart failure. Previously, we found that dantrolene produces up to a 45% inhibition RyR2 with an IC50 of 160 nM, and that this inhibition requires the physiological association between RyR2 and CaM. In this study, we tested the hypothesis that dantrolene inhibition of RyR2 in the presence of CaM is modulated by RyR2 phosphorylation at S2808 and S2814. Phosphorylation was altered by incubations with either exogenous phosphatase (PP1) or kinases; PKA to phosphorylate S2808 or endogenous CaMKII to phosphorylate S2814. We found that PKA caused selective dissociation of FKBP12.6 from the RyR2 complex and a loss of dantrolene inhibition. Rapamycin-induced FKBP12.6 dissociation from RyR2 also resulted in the loss of dantrolene inhibition. Subsequent incubations of RyR2 with exogenous FKBP12.6 reinstated dantrolene inhibition. These findings indicate that the inhibitory action of dantrolene on RyR2 depends on RyR2 association with FKBP12.6 in addition to CaM as previously found.
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Affiliation(s)
- Kafa Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia
| | - Nicole Beard
- Faculty of Science and Technology, University of Canberra, Bruce, Australia
| | - Dirk F. van Helden
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia
| | - Derek R. Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia
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5
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Svensson B, Nitu FR, Rebbeck RT, McGurran LM, Oda T, Thomas DD, Bers DM, Cornea RL. Molecular Mechanism of a FRET Biosensor for the Cardiac Ryanodine Receptor Pathologically Leaky State. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.07.548138. [PMID: 37461514 PMCID: PMC10350043 DOI: 10.1101/2023.07.07.548138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
Ca 2+ leak from cardiomyocyte sarcoplasmic reticulum (SR) via hyperactive resting cardiac ryanodine receptor channels (RyR2) is pro-arrhythmic. An exogenous peptide, (DPc10) detects leaky RyR2 in cardiomyocytes. Conversely, calmodulin (CaM) inhibits RyR2 leak. These observations have led to designing a FRET biosensor for drug discovery targeting RyR2. Here we used FRET to understand the molecular mechanism driving the DPc10-CaM interdependence when binding RyR2 in SR vesicles. We used donor-FKBP12.6 (D-FKBP) to resolve RyR2 binding of acceptor-CaM (A-CaM). In low nanomolar Ca 2+ , DPc10 decreased both FRET max (under saturating [A-CaM]) and the CaM/RyR2 binding affinity. In micromolar Ca 2+ , DPc10 decreased FRET max without affecting CaM/RyR2 binding affinity. This correlates with analysis of fluorescence-lifetime-detected FRET indicating that DPc10 lowers occupancy of the RyR2 CaM-binding sites in nanomolar (not micromolar) Ca 2+ and lengthens D-FKBP/A-CaM distances independent of [Ca 2+ ]. To observe DPc10/RyR2 binding, we used acceptor-DPc10 (A-DPc10). CaM weakens A-DPc10/RyR2 binding, this effect being larger in micromolar vs. nanomolar Ca 2+ . Moreover, A-DPc10/RyR2 binding is cooperative in CaM- and FKBP-dependent manner, suggesting that both endogenous modulators promote concerted structural changes between RyR2 protomers for channel regulation. Aided by analysis of cryo-EM structures, these insights inform further development of the DPc10-CaM paradigm for therapeutic discovery targeting RyR2.
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Affiliation(s)
- Bengt Svensson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis
| | - Florentin R. Nitu
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis
| | - Robyn T. Rebbeck
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis
| | - Lindsey M. McGurran
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis
| | - Tetsuro Oda
- Department of Pharmacology, University of California, Davis
| | - David D. Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis
| | - Donald M. Bers
- Department of Pharmacology, University of California, Davis
| | - Razvan L. Cornea
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis
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6
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Richardson SJ, Thekkedam CG, Casarotto MG, Beard NA, Dulhunty AF. FKBP12 binds to the cardiac ryanodine receptor with negative cooperativity: implications for heart muscle physiology in health and disease. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220169. [PMID: 37122219 PMCID: PMC10150220 DOI: 10.1098/rstb.2022.0169] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Cardiac ryanodine receptors (RyR2) release the Ca2+ from intracellular stores that is essential for cardiac myocyte contraction. The ion channel opening is tightly regulated by intracellular factors, including the FK506 binding proteins, FKBP12 and FKBP12.6. The impact of these proteins on RyR2 activity and cardiac contraction is debated, with often apparently contradictory experimental results, particularly for FKBP12. The isoform that regulates RyR2 has generally been considered to be FKBP12.6, despite the fact that FKBP12 is the major isoform associated with RyR2 in some species and is bound in similar proportions to FKBP12.6 in others, including sheep and humans. Here, we show time- and concentration-dependent effects of adding FKBP12 to RyR2 channels that were partly depleted of FKBP12/12.6 during isolation. The added FKBP12 displaced most remaining endogenous FKBP12/12.6. The results suggest that FKBP12 activates RyR2 with high affinity and inhibits RyR2 with lower affinity, consistent with a model of negative cooperativity in FKBP12 binding to each of the four subunits in the RyR tetramer. The easy dissociation of some FKBP12/12.6 could dynamically alter RyR2 activity in response to changes in in vivo regulatory factors, indicating a significant role for FKBP12/12.6 in Ca2+ signalling and cardiac function in healthy and diseased hearts. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- S J Richardson
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - C G Thekkedam
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - M G Casarotto
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - N A Beard
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - A F Dulhunty
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
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7
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Abstract
This Review provides an update on ryanodine receptors (RyRs) and their role in human diseases of heart, muscle, and brain. Calcium (Ca2+) is a requisite second messenger in all living organisms. From C. elegans to mammals, Ca2+ is necessary for locomotion, bodily functions, and neural activity. However, too much of a good thing can be bad. Intracellular Ca2+ overload can result in loss of function and death. Intracellular Ca2+ release channels evolved to safely provide large, rapid Ca2+ signals without exposure to toxic extracellular Ca2+. RyRs are intracellular Ca2+ release channels present throughout the zoosphere. Over the past 35 years, our knowledge of RyRs has advanced to the level of atomic-resolution structures revealing their role in the mechanisms underlying the pathogenesis of human disorders of heart, muscle, and brain. Stress-induced RyR-mediated intracellular Ca2+ leak in the heart can promote heart failure and cardiac arrhythmias. In skeletal muscle, RyR1 leak contributes to muscle weakness in inherited myopathies, to age-related loss of muscle function and cancer-associated muscle weakness, and to impaired muscle function in muscular dystrophies, including Duchenne. In the brain, leaky RyR channels contribute to cognitive dysfunction in Alzheimer's disease, posttraumatic stress disorder, and Huntington's disease. Novel therapeutics targeting dysfunctional RyRs are showing promise.
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8
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Xu B, Wang Y, Bahriz SMFM, Zhao M, Zhu C, Xiang YK. Probing spatiotemporal PKA activity at the ryanodine receptor and SERCA2a nanodomains in cardomyocytes. Cell Commun Signal 2022; 20:143. [PMID: 36104752 PMCID: PMC9472443 DOI: 10.1186/s12964-022-00947-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/23/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractSpatiotemporal regulation of subcellular protein kinase A (PKA) activity for precise substrate phosphorylation is essential for cellular responses to hormonal stimulation. Ryanodine receptor 2 (RyR2) and (sarco)endoplasmic reticulum calcium ATPase 2a (SERCA2a) represent two critical targets of β adrenoceptor (βAR) signaling on the sarcoplasmic reticulum membrane for cardiac excitation and contraction coupling. Using novel biosensors, we show that cardiac β1AR signals to both RyR2 and SERCA2a nanodomains in cardiomyocytes from mice, rats, and rabbits, whereas the β2AR signaling is restricted from these nanodomains. Phosphodiesterase 4 (PDE4) and PDE3 control the baseline PKA activity and prevent β2AR signaling from reaching the RyR2 and SERCA2a nanodomains. Moreover, blocking inhibitory G protein allows β2AR signaling to the RyR2 but not the SERCA2a nanodomains. This study provides evidence for the differential roles of inhibitory G protein and PDEs in controlling the adrenergic subtype signaling at the RyR2 and SERCA2a nanodomains in cardiomyocytes.
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9
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Molecular, Subcellular, and Arrhythmogenic Mechanisms in Genetic RyR2 Disease. Biomolecules 2022; 12:biom12081030. [PMID: 35892340 PMCID: PMC9394283 DOI: 10.3390/biom12081030] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 07/22/2022] [Accepted: 07/24/2022] [Indexed: 11/17/2022] Open
Abstract
The ryanodine receptor (RyR2) has a critical role in controlling Ca2+ release from the sarcoplasmic reticulum (SR) throughout the cardiac cycle. RyR2 protein has multiple functional domains with specific roles, and four of these RyR2 protomers are required to form the quaternary structure that comprises the functional channel. Numerous mutations in the gene encoding RyR2 protein have been identified and many are linked to a wide spectrum of arrhythmic heart disease. Gain of function mutations (GoF) result in a hyperactive channel that causes excessive spontaneous SR Ca2+ release. This is the predominant cause of the inherited syndrome catecholaminergic polymorphic ventricular tachycardia (CPVT). Recently, rare hypoactive loss of function (LoF) mutations have been identified that produce atypical effects on cardiac Ca2+ handling that has been termed calcium release deficiency syndrome (CRDS). Aberrant Ca2+ release resulting from both GoF and LoF mutations can result in arrhythmias through the Na+/Ca2+ exchange mechanism. This mini-review discusses recent findings regarding the role of RyR2 domains and endogenous regulators that influence RyR2 gating normally and with GoF/LoF mutations. The arrhythmogenic consequences of GoF/LoF mutations will then be discussed at the macromolecular and cellular level.
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10
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Rebbeck R, Ginsburg KS, Ko CY, Fasoli A, Rusch K, Cai GF, Dong X, Thomas DD, Bers DM, Cornea RL. Synergistic FRET assays for drug discovery targeting RyR2 channels. J Mol Cell Cardiol 2022; 168:13-23. [PMID: 35405106 PMCID: PMC10088286 DOI: 10.1016/j.yjmcc.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 03/09/2022] [Accepted: 04/05/2022] [Indexed: 10/18/2022]
Abstract
A key therapeutic target for heart failure and arrhythmia is the deleterious leak through sarcoplasmic reticulum (SR) ryanodine receptor 2 (RyR2) calcium release channels. We have previously developed methods to detect the pathologically leaky state of RyR2 in adult cardiomyocytes by monitoring RyR2 binding to either calmodulin (CaM) or a biosensor peptide (DPc10). Here, we test whether these complementary binding measurements are effective as high-throughput screening (HTS) assays to discover small molecules that target leaky RyR2. Using FRET, we developed and validated HTS procedures under conditions that mimic a pathological state, to screen the library of 1280 pharmaceutically active compounds (LOPAC) for modulators of RyR2 in cardiac SR membrane preparations. Complementary FRET assays with acceptor-labeled CaM and DPc10 were used for Hit prioritization based on the opposing binding properties of CaM vs. DPc10. This approach narrowed the Hit list to one compound, Ro 90-7501, which altered FRET to suggest increased RyR2-CaM binding and decreased DPc10 binding. Follow-up studies revealed that Ro 90-7501 does not detrimentally affect myocyte Ca2+ transients. Moreover, Ro 90-7501 partially inhibits overall Ca2+ leak, as assessed by Ca2+ sparks in permeabilized rat cardiomyocytes. Together, these results demonstrate (1) the effectiveness of our HTS approach where two complementary assays synergize for Hit ranking and (2) a drug discovery process that combines high-throughput, high-precision in vitro structural assays with in situ myocyte assays of the pathologic RyR2 leak. These provide a drug discovery platform compatible with large-scale HTS campaigns, to identify agents that inhibit RyR2 for therapeutic development.
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Affiliation(s)
- RobynT Rebbeck
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA
| | | | - Christopher Y Ko
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Anna Fasoli
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Katherine Rusch
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA
| | - George F Cai
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA
| | - Xiaoqiong Dong
- Department of Pharmacology, University of California, Davis, CA, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA; Photonic Pharma LLC, Minneapolis, MN, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA; Photonic Pharma LLC, Minneapolis, MN, USA.
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11
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Hernández Mesa M, van den Brink J, Louch WE, McCabe KJ, Rangamani P. Nanoscale organization of ryanodine receptor distribution and phosphorylation pattern determines the dynamics of calcium sparks. PLoS Comput Biol 2022; 18:e1010126. [PMID: 35666763 PMCID: PMC9203011 DOI: 10.1371/journal.pcbi.1010126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 06/16/2022] [Accepted: 04/20/2022] [Indexed: 11/18/2022] Open
Abstract
Super-resolution imaging techniques have provided a better understanding of the relationship between the nanoscale organization and function of ryanodine receptors (RyRs) in cardiomyocytes. Recent data have indicated that this relationship is disrupted in heart failure (HF), as RyRs are dispersed into smaller and more numerous clusters. However, RyRs are also hyperphosphorylated in this condition, and this is reported to occur preferentially within the cluster centre. Thus, the combined impact of RyR relocalization and sensitization on Ca2+ spark generation in failing cardiomyocytes is likely complex and these observations suggest that both the nanoscale organization of RyRs and the pattern of phosphorylated RyRs within clusters could be critical determinants of Ca2+ spark dynamics. To test this hypothesis, we used computational modeling to quantify the relationships between RyR cluster geometry, phosphorylation patterns, and sarcoplasmic reticulum (SR) Ca2+ release. We found that RyR cluster disruption results in a decrease in spark fidelity and longer sparks with a lower amplitude. Phosphorylation of some RyRs within the cluster can play a compensatory role, recovering healthy spark dynamics. Interestingly, our model predicts that such compensation is critically dependent on the phosphorylation pattern, as phosphorylation localized within the cluster center resulted in longer Ca2+ sparks and higher spark fidelity compared to a uniformly distributed phosphorylation pattern. Our results strongly suggest that both the phosphorylation pattern and nanoscale RyR reorganization are critical determinants of Ca2+ dynamics in HF.
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Affiliation(s)
- María Hernández Mesa
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Jonas van den Brink
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Kimberly J. McCabe
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, United States of America
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12
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Hadiatullah H, He Z, Yuchi Z. Structural Insight Into Ryanodine Receptor Channelopathies. Front Pharmacol 2022; 13:897494. [PMID: 35677449 PMCID: PMC9168041 DOI: 10.3389/fphar.2022.897494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/09/2022] [Indexed: 11/28/2022] Open
Abstract
The ryanodine receptors (RyRs) are large cation-selective ligand-gated channels that are expressed in the sarcoplasmic reticulum (SR) membrane. They mediate the controlled release of Ca2+ from SR and play an important role in many cellular processes. The mutations in RyRs are associated with several skeletal muscle and cardiac conditions, including malignant hyperthermia (MH), central core disease (CCD), catecholaminergic polymorphic ventricular tachycardia (CPVT), and arrhythmogenic right ventricular dysplasia (ARVD). Recent breakthroughs in structural biology including cryo-electron microscopy (EM) and X-ray crystallography allowed the determination of a number of near-atomic structures of RyRs, including wildtype and mutant structures as well as the structures in complex with different modulating molecules. This allows us to comprehend the physiological gating and regulatory mechanisms of RyRs and the underlying pathological mechanisms of the disease-causing mutations. In this review, based on the insights gained from the available high-resolution structures of RyRs, we address several questions: 1) what are the gating mechanisms of different RyR isoforms; 2) how RyRs are regulated by multiple channel modulators, including ions, small molecules, and regulatory proteins; 3) how do disease-causing mutations affect the structure and function of RyRs; 4) how can these structural information aid in the diagnosis of the related diseases and the development of pharmacological therapies.
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Affiliation(s)
- Hadiatullah Hadiatullah
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin’s Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Zhao He
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin’s Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin’s Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
- *Correspondence: Zhiguang Yuchi,
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13
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Therapeutic Approaches of Ryanodine Receptor-Associated Heart Diseases. Int J Mol Sci 2022; 23:ijms23084435. [PMID: 35457253 PMCID: PMC9031589 DOI: 10.3390/ijms23084435] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 01/08/2023] Open
Abstract
Cardiac diseases are the leading causes of death, with a growing number of cases worldwide, posing a challenge for both healthcare and research. Therefore, the most relevant aim of cardiac research is to unravel the molecular pathomechanisms and identify new therapeutic targets. Cardiac ryanodine receptor (RyR2), the Ca2+ release channel of the sarcoplasmic reticulum, is believed to be a good therapeutic target in a group of certain heart diseases, collectively called cardiac ryanopathies. Ryanopathies are associated with the impaired function of the RyR, leading to heart diseases such as congestive heart failure (CHF), catecholaminergic polymorphic ventricular tachycardia (CPVT), arrhythmogenic right ventricular dysplasia type 2 (ARVD2), and calcium release deficiency syndrome (CRDS). The aim of the current review is to provide a short insight into the pathological mechanisms of ryanopathies and discuss the pharmacological approaches targeting RyR2.
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14
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Fernández-Morales JC, Xia Y, Rienzo TJ, Zhang XH, Morad M. Mutation in RyR2-FKBP Binding site alters Ca 2+ signaling modestly but increases "arrhythmogenesis" in human stem cells derived cardiomyocytes. Cell Calcium 2022; 101:102500. [PMID: 34813985 PMCID: PMC8752506 DOI: 10.1016/j.ceca.2021.102500] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 01/03/2023]
Abstract
AIMS To gain insights into FKBP regulation of cardiac ryanodine receptor (RyR2) and Ca2+ signaling, we introduced the point mutation (N771D-RyR2) corresponding to skeletal muscle mutation (N760D-RyR1) associated with central core disease (CCD) via CRISPR/Cas9 gene-editing in the RyR2 FKBP binding site expressed in human induced pluripotent stem cell-derived cardiomyocytes (hiPSCCMs). Patients inflicted with CCD and other hereditary skeletal muscle diseases often show higher incidence of atrial or ventricular arrhythmias. METHODS AND RESULTS Ca2+ imaging of voltage-clamped N771D-RyR2 mutant compared to WT hiPSCCMs showed: (1) ∼30% suppressed ICa with no significant changes in the gating kinetics of ICa; (2) 29% lower SR Ca2+ content and 33% lower RyR2 Ca2+ leak; (3) higher CICR gain and 30-35% increased efficiency of ICa-triggered Ca2±release; (4) higher incidence of aberrant SR Ca2+ releases, DADs, and Ca2+ sparks; (5) no change in fractional Ca2+-release, action potential morphology, sensitivity to isoproterenol, and sarcomeric FKBP-binding pattern. CONCLUSIONS The more frequent spontaneous Ca2+ releases and longer Ca2+ sparks underlie the increased incidence of DADs and cellular arrhythmogenesis of N771D-RyR2 mutant. The smaller RyR2 Ca2±leak and SR content result from suppressed ICathat is compensated by higher CICR gain.
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Affiliation(s)
| | - Yanli Xia
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Taylor J. Rienzo
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Xiao-Hua Zhang
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Martin Morad
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA.,Department of Pharmacology, Georgetown University Medical Center, Washington, DC, USA
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15
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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.
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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
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16
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Iop L. Toward the Effective Bioengineering of a Pathological Tissue for Cardiovascular Disease Modeling: Old Strategies and New Frontiers for Prevention, Diagnosis, and Therapy. Front Cardiovasc Med 2021; 7:591583. [PMID: 33748193 PMCID: PMC7969521 DOI: 10.3389/fcvm.2020.591583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/08/2020] [Indexed: 12/18/2022] Open
Abstract
Cardiovascular diseases (CVDs) still represent the primary cause of mortality worldwide. Preclinical modeling by recapitulating human pathophysiology is fundamental to advance the comprehension of these diseases and propose effective strategies for their prevention, diagnosis, and treatment. In silico, in vivo, and in vitro models have been applied to dissect many cardiovascular pathologies. Computational and bioinformatic simulations allow developing algorithmic disease models considering all known variables and severity degrees of disease. In vivo studies based on small or large animals have a long tradition and largely contribute to the current treatment and management of CVDs. In vitro investigation with two-dimensional cell culture demonstrates its suitability to analyze the behavior of single, diseased cellular types. The introduction of induced pluripotent stem cell technology and the application of bioengineering principles raised the bar toward in vitro three-dimensional modeling by enabling the development of pathological tissue equivalents. This review article intends to describe the advantages and disadvantages of past and present modeling approaches applied to provide insights on some of the most relevant congenital and acquired CVDs, such as rhythm disturbances, bicuspid aortic valve, cardiac infections and autoimmunity, cardiovascular fibrosis, atherosclerosis, and calcific aortic valve stenosis.
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Affiliation(s)
- Laura Iop
- Department of Cardiac Thoracic Vascular Sciences, and Public Health, University of Padua Medical School, Padua, Italy
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17
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Gong D, Yan N, Ledford HA. Structural Basis for the Modulation of Ryanodine Receptors. Trends Biochem Sci 2020; 46:489-501. [PMID: 33353849 DOI: 10.1016/j.tibs.2020.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 12/11/2022]
Abstract
Historically, ryanodine receptors (RyRs) have presented unique challenges for high-resolution structural determination despite long-standing interest in their role in excitation-contraction coupling. Owing to their large size (nearly 2.2 MDa), high-resolution structures remained elusive until the advent of cryogenic electron microscopy (cryo-EM) techniques. In recent years, structures for both RyR1 and RyR2 have been solved at near-atomic resolution. Furthermore, recent reports have delved into their more complex structural associations with key modulators - proteins such as the dihydropyridine receptor (DHPR), FKBP12/12.6, and calmodulin (CaM), as well as ions and small molecules including Ca2+, ATP, caffeine, and PCB95. This review addresses the modulation of RyR1 and RyR2, in addition to the impact of such discoveries on intracellular Ca2+ dynamics and biophysical properties.
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Affiliation(s)
- Deshun Gong
- Zhejiang Provincial Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province/Key Laboratory of Growth Regulation and Transformation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang Province, China.
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Hannah A Ledford
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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18
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Dridi H, Kushnir A, Zalk R, Yuan Q, Melville Z, Marks AR. Intracellular calcium leak in heart failure and atrial fibrillation: a unifying mechanism and therapeutic target. Nat Rev Cardiol 2020; 17:732-747. [PMID: 32555383 PMCID: PMC8362847 DOI: 10.1038/s41569-020-0394-8] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/06/2020] [Indexed: 12/14/2022]
Abstract
Ca2+ is a fundamental second messenger in all cell types and is required for numerous essential cellular functions, including cardiac and skeletal muscle contraction. The intracellular concentration of free Ca2+ ([Ca2+]) is regulated primarily by ion channels, pumps (ATPases), exchangers and Ca2+-binding proteins. Defective regulation of [Ca2+] is found in a diverse spectrum of pathological states that affect all the major organs. In the heart, abnormalities in the regulation of cytosolic and mitochondrial [Ca2+] occur in heart failure (HF) and atrial fibrillation (AF), two common forms of heart disease and leading contributors to morbidity and mortality. In this Review, we focus on the mechanisms that regulate ryanodine receptor 2 (RYR2), the major sarcoplasmic reticulum (SR) Ca2+-release channel in the heart, how RYR2 becomes dysfunctional in HF and AF, and its potential as a therapeutic target. Inherited RYR2 mutations and/or stress-induced phosphorylation and oxidation of the protein destabilize the closed state of the channel, resulting in a pathological diastolic Ca2+ leak from the SR that both triggers arrhythmias and impairs contractility. On the basis of our increased understanding of SR Ca2+ leak as a shared Ca2+-dependent pathological mechanism in HF and AF, a new class of drugs developed in our laboratory, known as rycals, which stabilize RYR2 channels and prevent Ca2+ leak from the SR, are undergoing investigation in clinical trials.
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Affiliation(s)
- Haikel Dridi
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Ran Zalk
- The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Qi Yuan
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Zephan Melville
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
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19
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Mei L, Zheng YM, Song T, Yadav VR, Joseph LC, Truong L, Kandhi S, Barroso MM, Takeshima H, Judson MA, Wang YX. Rieske iron-sulfur protein induces FKBP12.6/RyR2 complex remodeling and subsequent pulmonary hypertension through NF-κB/cyclin D1 pathway. Nat Commun 2020; 11:3527. [PMID: 32669538 PMCID: PMC7363799 DOI: 10.1038/s41467-020-17314-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 06/17/2020] [Indexed: 02/07/2023] Open
Abstract
Ca2+ signaling in pulmonary arterial smooth muscle cells (PASMCs) plays an important role in pulmonary hypertension (PH). However, the underlying specific ion channel mechanisms remain largely unknown. Here, we report ryanodine receptor (RyR) channel activity and Ca2+ release both are increased, and association of RyR2 by FK506 binding protein 12.6 (FKBP12.6) is decreased in PASMCs from mice with chronic hypoxia (CH)-induced PH. Smooth muscle cell (SMC)-specific RyR2 knockout (KO) or Rieske iron-sulfur protein (RISP) knockdown inhibits the altered Ca2+ signaling, increased nuclear factor (NF)-κB/cyclin D1 activation and cell proliferation, and CH-induced PH in mice. FKBP12.6 KO or FK506 treatment enhances CH-induced PH, while S107 (a specific stabilizer of RyR2/FKBP12.6 complex) produces an opposite effect. In conclusion, CH causes RISP-dependent ROS generation and FKBP12.6/RyR2 dissociation, leading to PH. RISP inhibition, RyR2/FKBP12.6 complex stabilization and Ca2+ release blockade may be potentially beneficial for the treatment of PH.
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Affiliation(s)
- Lin Mei
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA
| | - Yun-Min Zheng
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA
| | - Tengyao Song
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA
| | - Vishal R Yadav
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA
| | - Leroy C Joseph
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA
| | - Lillian Truong
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA
| | - Sharath Kandhi
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA
| | - Margarida M Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Kyoto, Japan
| | - Marc A Judson
- Division of Pulmonary and Critical Care Medicine, Albany Medical College, Albany, 12208, NY, USA
| | - Yong-Xiao Wang
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, 12208, NY, USA.
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20
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Gilbert G, Demydenko K, Dries E, Puertas RD, Jin X, Sipido K, Roderick HL. Calcium Signaling in Cardiomyocyte Function. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035428. [PMID: 31308143 DOI: 10.1101/cshperspect.a035428] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rhythmic increases in intracellular Ca2+ concentration underlie the contractile function of the heart. These heart muscle-wide changes in intracellular Ca2+ are induced and coordinated by electrical depolarization of the cardiomyocyte sarcolemma by the action potential. Originating at the sinoatrial node, conduction of this electrical signal throughout the heart ensures synchronization of individual myocytes into an effective cardiac pump. Ca2+ signaling pathways also regulate gene expression and cardiomyocyte growth during development and in pathology. These fundamental roles of Ca2+ in the heart are illustrated by the prevalence of altered Ca2+ homeostasis in cardiovascular diseases. Indeed, heart failure (an inability of the heart to support hemodynamic needs), rhythmic disturbances, and inappropriate cardiac growth all share an involvement of altered Ca2+ handling. The prevalence of these pathologies, contributing to a third of all deaths in the developed world as well as to substantial morbidity makes understanding the mechanisms of Ca2+ handling and dysregulation in cardiomyocytes of great importance.
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Affiliation(s)
- Guillaume Gilbert
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Kateryna Demydenko
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Eef Dries
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Rosa Doñate Puertas
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Xin Jin
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Karin Sipido
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
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21
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Zheng J, Zhou H, Yang M, Song S, Dai Q, Ji G, Zhou Z. Reduced Ca 2+ spark activity contributes to detrusor overactivity of rats with partial bladder outlet obstruction. Aging (Albany NY) 2020; 12:4163-4177. [PMID: 32112553 PMCID: PMC7093189 DOI: 10.18632/aging.102855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 01/28/2020] [Indexed: 12/19/2022]
Abstract
We tested whether or not altered Ca2+ spark activity accounted for detrusor overactivity (DO) of Wistar rats after partial bladder outlet obstruction (PBOO). We constructed a DO model through PBOO and studied the Ca2+ spark activity of detrusor. By way of using confocal microscopy and the patch-clamp technique, Ca2+ sparks and spontaneous transient outward currents (STOCs) in detrusor myocytes were measured respectively. Our results indicated that Ca2+ spark activity and STOCs were significantly reduced in the DO detrusor myocytes compared to unafflicted control cells, and both of these had levels that were remarkably increased by applications of caffeine (10 μM), a RyR agonist, in DO myocytes. In addition, measures of detrusor contractions were also recorded by using freshly isolated detrusor strips. These results indicated that the spontaneous contraction of DO detrusor was significantly enhanced, and that the effect of caffeine (10 μM) upon detrusor contractions was reversed by applications of iberiotoxin (100 nM) which is a BK channel blocker. Western blotting (WB) analyses indicated that the levels of expression of ryanodine receptor type 2 (RyR2) and FK506 binding protein 12.6 (FKBP12.6) in bladder muscle were respectively decreased and increased in the samples from DO rats. Thus, we considered in the rat DO model wherein PBOO, the reduced Ca2+ spark activity in detrusor myocytes partly contributed to overactive detrusor contractions. The impaired Ca2+ spark activity may have resulted from decreased RyR2 expression and increased FKBP12.6 expression. Such novel findings in our research might help to provide means for better treatment outcomes for patients afflicted by bladder dysfunction.
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Affiliation(s)
- Ji Zheng
- Department of Urology, Urological Surgery Research Institute, First Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Hao Zhou
- Department of Urology, Urological Surgery Research Institute, First Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Mengjun Yang
- Department of Urology, Urological Surgery Research Institute, First Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Siji Song
- Department of Urology, Urological Surgery Research Institute, First Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Qiang Dai
- Department of Urology, Urological Surgery Research Institute, First Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Guangju Ji
- Key Laboratory of Interdisciplinary Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100049, China
| | - Zhansong Zhou
- Department of Urology, Urological Surgery Research Institute, First Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing 400038, China
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22
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RyR1-targeted drug discovery pipeline integrating FRET-based high-throughput screening and human myofiber dynamic Ca 2+ assays. Sci Rep 2020; 10:1791. [PMID: 32019969 PMCID: PMC7000700 DOI: 10.1038/s41598-020-58461-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 01/13/2020] [Indexed: 11/18/2022] Open
Abstract
Elevated cytoplasmic [Ca2+] is characteristic in severe skeletal and cardiac myopathies, diabetes, and neurodegeneration, and partly results from increased Ca2+ leak from sarcoplasmic reticulum stores via dysregulated ryanodine receptor (RyR) channels. Consequently, RyR is recognized as a high-value target for drug discovery to treat such pathologies. Using a FRET-based high-throughput screening assay that we previously reported, we identified small-molecule compounds that modulate the skeletal muscle channel isoform (RyR1) interaction with calmodulin and FK506 binding protein 12.6. Two such compounds, chloroxine and myricetin, increase FRET and inhibit [3H]ryanodine binding to RyR1 at nanomolar Ca2+. Both compounds also decrease RyR1 Ca2+ leak in human skinned skeletal muscle fibers. Furthermore, we identified compound concentrations that reduced leak by > 50% but only slightly affected Ca2+ release in excitation-contraction coupling, which is essential for normal muscle contraction. This report demonstrates a pipeline that effectively filters small-molecule RyR1 modulators towards clinical relevance.
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23
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Federico M, Valverde CA, Mattiazzi A, Palomeque J. Unbalance Between Sarcoplasmic Reticulum Ca 2 + Uptake and Release: A First Step Toward Ca 2 + Triggered Arrhythmias and Cardiac Damage. Front Physiol 2020; 10:1630. [PMID: 32038301 PMCID: PMC6989610 DOI: 10.3389/fphys.2019.01630] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 12/24/2019] [Indexed: 12/19/2022] Open
Abstract
The present review focusses on the regulation and interplay of cardiac SR Ca2+ handling proteins involved in SR Ca2+ uptake and release, i.e., SERCa2/PLN and RyR2. Both RyR2 and SERCA2a/PLN are highly regulated by post-translational modifications and/or different partners' proteins. These control mechanisms guarantee a precise equilibrium between SR Ca2+ reuptake and release. The review then discusses how disruption of this balance alters SR Ca2+ handling and may constitute a first step toward cardiac damage and malignant arrhythmias. In the last part of the review, this concept is exemplified in different cardiac diseases, like prediabetic and diabetic cardiomyopathy, digitalis intoxication and ischemia-reperfusion injury.
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Affiliation(s)
- Marilén Federico
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", CCT-La Plata/CONICET, Facultad de Cs. Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Carlos A Valverde
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", CCT-La Plata/CONICET, Facultad de Cs. Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", CCT-La Plata/CONICET, Facultad de Cs. Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Julieta Palomeque
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", CCT-La Plata/CONICET, Facultad de Cs. Médicas, Universidad Nacional de La Plata, La Plata, Argentina.,Centro de Altos Estudios en Ciencias Humanas y de la Salud, Universidad Abierta Interamericana, Buenos Aires, Argentina
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24
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Asghari P, Scriven DR, Ng M, Panwar P, Chou KC, van Petegem F, Moore ED. Cardiac ryanodine receptor distribution is dynamic and changed by auxiliary proteins and post-translational modification. eLife 2020; 9:51602. [PMID: 31916935 PMCID: PMC6994221 DOI: 10.7554/elife.51602] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/09/2020] [Indexed: 12/14/2022] Open
Abstract
The effects of the immunophilins, FKBP12 and FKBP12.6, and phosphorylation on type II ryanodine receptor (RyR2) arrangement and function were examined using correlation microscopy (line scan confocal imaging of Ca2+ sparks and dual-tilt electron tomography) and dSTORM imaging of permeabilized Wistar rat ventricular myocytes. Saturating concentrations (10 µmol/L) of either FKBP12 or 12.6 significantly reduced the frequency, spread, amplitude and Ca2+ spark mass relative to control, while the tomograms revealed both proteins shifted the tetramers into a largely side-by-side configuration. Phosphorylation of immunophilin-saturated RyR2 resulted in structural and functional changes largely comparable to phosphorylation alone. dSTORM images of myocyte surfaces demonstrated that both FKBP12 and 12.6 significantly reduced RyR2 cluster sizes, while phosphorylation, even of immunophilin-saturated RyR2, increased them. We conclude that both RyR2 cluster size and the arrangement of tetramers within clusters is dynamic and respond to changes in the cellular environment. Further, these changes affect Ca2+ spark formation.
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Affiliation(s)
- Parisa Asghari
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - David Rl Scriven
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Myles Ng
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Pankaj Panwar
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Keng C Chou
- Department of Chemistry, University of British Columbia, Vancouver, Canada
| | - Filip van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Edwin Dw Moore
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
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25
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Molecular basis for allosteric regulation of the type 2 ryanodine receptor channel gating by key modulators. Proc Natl Acad Sci U S A 2019; 116:25575-25582. [PMID: 31792195 PMCID: PMC6926060 DOI: 10.1073/pnas.1914451116] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
As a switch for the release of Ca2+ from the sarco(endo)plasmic reticulum of cardiomyocytes, the type 2 ryanodine receptor (RyR2) is subject to sophisticated regulation by a broad spectrum of modulators. Dysregulation of RyR2-mediated Ca2+ release is linked to life-threatening cardiac arrhythmias. The regulatory mechanism of RyR2 by key modulators, such as Ca2+, FKBP12.6, ATP, and caffeine, remains unclear. This study provides important insights into the long-range allosteric regulation of RyR2 channel gating by these modulators and serves as an important framework for mechanistic understanding of the regulation of this key player in the excitation–contraction coupling of cardiac muscles. The type 2 ryanodine receptor (RyR2) is responsible for releasing Ca2+ from the sarcoplasmic reticulum of cardiomyocytes, subsequently leading to muscle contraction. Here, we report 4 cryo-electron microscopy (cryo-EM) structures of porcine RyR2 bound to distinct modulators that, together with our published structures, provide mechanistic insight into RyR2 regulation. Ca2+ alone induces a contraction of the central domain that facilitates the dilation of the S6 bundle but is insufficient to open the pore. The small-molecule agonist PCB95 helps Ca2+ to overcome the barrier for opening. FKBP12.6 induces a relaxation of the central domain that decouples it from the S6 bundle, stabilizing RyR2 in a closed state even in the presence of Ca2+ and PCB95. Although the channel is open when PCB95 is replaced by caffeine and adenosine 5′-triphosphate (ATP), neither of the modulators alone can sufficiently counter the antagonistic effect to open the channel. Our study marks an important step toward mechanistic understanding of the sophisticated regulation of this key channel whose aberrant activity engenders life-threatening cardiac disorders.
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26
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Hu XQ, Song R, Romero M, Dasgupta C, Huang X, Holguin MA, Williams V, Xiao D, Wilson SM, Zhang L. Pregnancy Increases Ca 2+ Sparks/Spontaneous Transient Outward Currents and Reduces Uterine Arterial Myogenic Tone. Hypertension 2019; 73:691-702. [PMID: 30661479 DOI: 10.1161/hypertensionaha.118.12484] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Spontaneous transient outward currents (STOCs) at physiological membrane potentials of vascular smooth muscle cells fundamentally regulate vascular myogenic tone and blood flow in an organ. We hypothesize that heightened STOCs play a key role in uterine vascular adaptation to pregnancy. Uterine arteries were isolated from nonpregnant and near-term pregnant sheep. Ca2+ sparks were measured by confocal microscopy, and STOCs were determined by electrophysiological recording in smooth muscle cells. Percentage of Ca2+ spark firing myocytes increased dramatically at the resting condition in uterine arterial smooth muscle of pregnant animals, as compared with nonpregnant animals. Pregnancy upregulated the expression of RyRs (ryanodine receptors) and significantly boosted Ca2+ spark frequency. Ex vivo treatment of uterine arteries of nonpregnant sheep with estrogen and progesterone imitated pregnancy-induced RyR upregulation. STOCs occurred at much more negative membrane potentials in uterine arterial myocytes of pregnant animals. STOCs in uterine arterial myocytes were diminished by inhibiting large-conductance Ca2+-activated K+ (BKCa) channels and RyRs, thus functionally linking Ca2+ sparks and BKCa channel activity to STOCs. Pregnancy and steroid hormone treatment significantly increased STOCs frequency and amplitude in uterine arteries. Of importance, inhibition of STOCs with RyR inhibitor ryanodine eliminated pregnancy- and steroid hormone-induced attenuation of uterine arterial myogenic tone. Thus, the present study demonstrates a novel role of Ca2+ sparks and STOCs in the regulation of uterine vascular tone and provides new insights into the mechanisms underlying uterine vascular adaptation to pregnancy.
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Affiliation(s)
- Xiang-Qun Hu
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - Rui Song
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - Monica Romero
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - Chiranjib Dasgupta
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - Xiaohui Huang
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - Mark A Holguin
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - VaShon Williams
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - Daliao Xiao
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - Sean M Wilson
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
| | - Lubo Zhang
- From the Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, CA
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27
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Xu T, Yuchi Z. Crystal structure of diamondback moth ryanodine receptor Repeat34 domain reveals insect-specific phosphorylation sites. BMC Biol 2019; 17:77. [PMID: 31597572 PMCID: PMC6784350 DOI: 10.1186/s12915-019-0698-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/02/2019] [Indexed: 01/23/2023] Open
Abstract
Background Ryanodine receptor (RyR), a calcium-release channel located in the sarcoplasmic reticulum membrane of muscles, is the target of insecticides used against a wide range of agricultural pests. Mammalian RyRs have been shown to be under the regulatory control of several kinases and phosphatases, but little is known about the regulation of insect RyRs by phosphorylation. Results Here we present the crystal structures of wild-type and phospho-mimetic RyR Repeat34 domain containing PKA phosphorylation sites from diamondback moth (DBM), a major lepidopteran pest of cruciferous vegetables. The structure has unique features, not seen in mammalian RyRs, including an additional α-helix near the phosphorylation loop. Using tandem mass spectrometry, we identify several PKA sites clustering in the phosphorylation loop and the newly identified α-helix. Bioinformatics analysis shows that this α-helix is only present in Lepidoptera, suggesting an insect-specific regulation. Interestingly, the specific phosphorylation pattern is temperature-dependent. The thermal stability of the DBM Repeat34 domain is significantly lower than that of the analogous domain in the three mammalian RyR isoforms, indicating a more dynamic domain structure that can be partially unfolded to facilitate the temperature-dependent phosphorylation. Docking the structure into the cryo-electron microscopy model of full-length RyR reveals that the interface between the Repeat34 and neighboring HD1 domain is more conserved than that of the phosphorylation loop region that might be involved in the interaction with SPRY3 domain. We also identify an insect-specific glycerol-binding pocket that could be potentially targeted by novel insecticides to fight the current resistance crisis. Conclusions The crystal structures of the DBM Repeat34 domain reveals insect-specific temperature-dependent phosphorylation sites that may regulate insect ryanodine receptor function. It also reveals insect-specific structural features and a potential ligand-binding site that could be targeted in an effort to develop green pesticides with high species-specificity.
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Affiliation(s)
- Tong Xu
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China.
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28
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Sheard TD, Hurley ME, Colyer J, White E, Norman R, Pervolaraki E, Narayanasamy KK, Hou Y, Kirton HM, Yang Z, Hunter L, Shim JU, Clowsley AH, Smith AJ, Baddeley D, Soeller C, Colman MA, Jayasinghe I. Three-Dimensional and Chemical Mapping of Intracellular Signaling Nanodomains in Health and Disease with Enhanced Expansion Microscopy. ACS NANO 2019; 13:2143-2157. [PMID: 30715853 PMCID: PMC6396323 DOI: 10.1021/acsnano.8b08742] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 02/04/2019] [Indexed: 05/08/2023]
Abstract
Nanodomains are intracellular foci which transduce signals between major cellular compartments. One of the most ubiquitous signal transducers, the ryanodine receptor (RyR) calcium channel, is tightly clustered within these nanodomains. Super-resolution microscopy has previously been used to visualize RyR clusters near the cell surface. A majority of nanodomains located deeper within cells have remained unresolved due to limited imaging depths and axial resolution of these modalities. A series of enhancements made to expansion microscopy allowed individual RyRs to be resolved within planar nanodomains at the cell periphery and the curved nanodomains located deeper within the interiors of cardiomyocytes. With a resolution of ∼ 15 nm, we localized both the position of RyRs and their individual phosphorylation for the residue Ser2808. With a three-dimensional imaging protocol, we observed disturbances to the RyR arrays in the nanometer scale which accompanied right-heart failure caused by pulmonary hypertension. The disease coincided with a distinct gradient of RyR hyperphosphorylation from the edge of the nanodomain toward the center, not seen in healthy cells. This spatial profile appeared to contrast distinctly from that sustained by the cells during acute, physiological hyperphosphorylation when they were stimulated with a β-adrenergic agonist. Simulations of RyR arrays based on the experimentally determined channel positions and phosphorylation signatures showed how the nanoscale dispersal of the RyRs during pathology diminishes its intrinsic likelihood to ignite a calcium signal. It also revealed that the natural topography of RyR phosphorylation could offset potential heterogeneity in nanodomain excitability which may arise from such RyR reorganization.
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Affiliation(s)
- Thomas
M. D. Sheard
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Miriam E. Hurley
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - John Colyer
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Ed White
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Ruth Norman
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Eleftheria Pervolaraki
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Kaarjel K. Narayanasamy
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Yufeng Hou
- Institute
of Experimental Medical Research, Oslo University
Hospital Ullevål, Oslo 0407, Norway
| | - Hannah M. Kirton
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Zhaokang Yang
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Liam Hunter
- School
of Physics and Astronomy, Faculty of Mathematics and Physical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Jung-uk Shim
- School
of Physics and Astronomy, Faculty of Mathematics and Physical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | - Andrew J. Smith
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - David Baddeley
- Auckland
Bioengineering Institute, University of
Auckland, UniServices
House, Level, 6/70 Symonds St, Grafton, Auckland 1010, New Zealand
| | - Christian Soeller
- Living
Systems Institute, University of Exeter, Devon EX4 4QL, United Kingdom
| | - Michael A. Colman
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Izzy Jayasinghe
- School
of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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29
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Xie Y, Yang Y, Galice S, Bers DM, Sato D. Size Matters: Ryanodine Receptor Cluster Size Heterogeneity Potentiates Calcium Waves. Biophys J 2019; 116:530-539. [PMID: 30686487 PMCID: PMC6369574 DOI: 10.1016/j.bpj.2018.12.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 11/11/2018] [Accepted: 12/12/2018] [Indexed: 12/21/2022] Open
Abstract
Ryanodine receptors (RyRs) mediate calcium (Ca)-induced Ca release and intracellular Ca homeostasis. In a cardiac myocyte, RyRs group into clusters of variable size from a few to several hundred RyRs, creating a spatially nonuniform intracellular distribution. It is unclear how heterogeneity of RyR cluster size alters spontaneous sarcoplasmic reticulum (SR) Ca releases (Ca sparks) and arrhythmogenic Ca waves. Here, we tested the impact of heterogeneous RyR cluster size on the initiation of Ca waves. Experimentally, we measured RyR cluster sizes at Ca spark sites in rat ventricular myocytes and further tested functional impacts using a physiologically detailed computational model with spatial and stochastic intracellular Ca dynamics. We found that the spark frequency and amplitude increase nonlinearly with the size of RyR clusters. Larger RyR clusters have lower SR Ca release threshold for local Ca spark initiation and exhibit steeper SR Ca release versus SR Ca load relationship. However, larger RyR clusters tend to lower SR Ca load because of the higher Ca leak rate. Conversely, smaller clusters have a higher threshold and a lower leak, which tends to increase SR Ca load. At the myocyte level, homogeneously large or small RyR clusters limit Ca waves (because of low load for large clusters but low excitability for small clusters). Mixtures of large and small RyR clusters potentiates Ca waves because the enhanced SR Ca load driven by smaller clusters enables Ca wave initiation and propagation from larger RyR clusters. Our study suggests that a spatially heterogeneous distribution of RyR cluster size under pathological conditions may potentiate Ca waves and thus afterdepolarizations and triggered arrhythmias.
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Affiliation(s)
- Yuanfang Xie
- Department of Pharmacology, University of California Davis, Davis, California
| | - Yi Yang
- Department of Pharmacology, University of California Davis, Davis, California
| | - Samuel Galice
- Department of Pharmacology, University of California Davis, Davis, California
| | - Donald M Bers
- Department of Pharmacology, University of California Davis, Davis, California
| | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, California.
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30
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Kolos JM, Voll AM, Bauder M, Hausch F. FKBP Ligands-Where We Are and Where to Go? Front Pharmacol 2018; 9:1425. [PMID: 30568592 PMCID: PMC6290070 DOI: 10.3389/fphar.2018.01425] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/19/2018] [Indexed: 12/24/2022] Open
Abstract
In recent years, many members of the FK506-binding protein (FKBP) family were increasingly linked to various diseases. The binding domain of FKBPs differs only in a few amino acid residues, but their biological roles are versatile. High-affinity ligands with selectivity between close homologs are scarce. This review will give an overview of the most prominent ligands developed for FKBPs and highlight a perspective for future developments. More precisely, human FKBPs and correlated diseases will be discussed as well as microbial FKBPs in the context of anti-bacterial and anti-fungal therapeutics. The last section gives insights into high-affinity ligands as chemical tools and dimerizers.
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Affiliation(s)
| | | | | | - Felix Hausch
- Department of Chemistry, Institute of Chemistry and Biochemistry, Darmstadt University of Technology, Darmstadt, Germany
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31
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018. [PMID: 30425651 DOI: 10.3389/fphys.2018.01517, 10.3389/fpls.2018.01517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
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32
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018; 9:1517. [PMID: 30425651 PMCID: PMC6218530 DOI: 10.3389/fphys.2018.01517] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/09/2018] [Indexed: 12/28/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States.,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
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33
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Hamilton S, Terentyev D. Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity. Front Physiol 2018; 9:1517. [PMID: 30425651 PMCID: PMC6218530 DOI: 10.3389/fphys.2018.01517,+10.3389/fpls.2018.01517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022] Open
Abstract
A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis.
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Affiliation(s)
- Shanna Hamilton
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States
| | - Dmitry Terentyev
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, United States,Cardiovascular Research Center, Rhode Island Hospital, Providence, RI, United States,*Correspondence: Dmitry Terentyev,
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34
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Liu D, Zheng S, Zheng G, Lv Q, Shen B, Yuan X, Pan YH. Adaptation of the FK506 binding protein 1B to hibernation in bats. Cryobiology 2018; 83:1-8. [PMID: 30056853 DOI: 10.1016/j.cryobiol.2018.07.004] [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: 03/30/2018] [Revised: 06/29/2018] [Accepted: 07/03/2018] [Indexed: 10/28/2022]
Abstract
Hibernation is an adaptive strategy used by some animals to cope with cold and food shortage. The heart rate, overall energy need, body temperature, and many other physiological functions are greatly reduced during torpor but promptly return to normal levels upon arousal. The heartbeat of torpid bats can be hundreds fold lower than that of active bats, indicating that hibernating bats have a remarkable ability to control excitation-contraction coupling in cardiac muscle. FKBP1B (calstabin 2), a peptidyl-prolyl cis-trans isomerase, is critical for the regulation of excitation-contraction coupling. Whether FKBP1B is adapted to hibernation in bats is not known. Evolutionary analyses showed that the ω values of the Fkbp1b genes of 25 mammalian species are all less than 1, and amino acid sequence alignments revealed that FKBP1B proteins are highly conserved in mammals. The expression of the Fkbp1b gene was found to be elevated at both mRNA and protein levels in two distantly related bats (Rhinolophus ferrumequinum in Yinpterochiroptera and Myotis ricketti in Yangochiroptera) during torpor. Transcription factors such as YY1 and SPs were bioinformatically determined to have a higher binding affinity to the potential regulatory regions of Fkbp1b genes in hibernating than in non-hibernating mammals. This study provides new insights into the molecular evolution of Fkbp1b in adaptation to bat hibernation.
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Affiliation(s)
- Di Liu
- Laboratory of Molecular Biology and Evolution, School of Life Science, East China Normal University, Shanghai, China
| | - Shenghui Zheng
- Laboratory of Molecular Biology and Evolution, School of Life Science, East China Normal University, Shanghai, China
| | - Guantao Zheng
- Center of Molecular Therapeutics and New Drug Development, East China Normal University, Shanghai, China
| | - Qingyun Lv
- Laboratory of Molecular Biology and Evolution, School of Life Science, East China Normal University, Shanghai, China
| | - Bin Shen
- National Engineering Research Center of Marine Aquaculture, College of Marine Science, Zhejiang Ocean University, Zhoushan, China
| | - Xinpu Yuan
- Laboratory of Molecular Biology and Evolution, School of Life Science, East China Normal University, Shanghai, China
| | - Yi-Hsuan Pan
- Laboratory of Molecular Biology and Evolution, School of Life Science, East China Normal University, Shanghai, China.
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35
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Galice S, Xie Y, Yang Y, Sato D, Bers DM. Size Matters: Ryanodine Receptor Cluster Size Affects Arrhythmogenic Sarcoplasmic Reticulum Calcium Release. J Am Heart Assoc 2018; 7:e008724. [PMID: 29929992 PMCID: PMC6064922 DOI: 10.1161/jaha.118.008724] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/16/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND Ryanodine receptors (RyR) mediate sarcoplasmic reticulum calcium (Ca2+) release and influence myocyte Ca2+ homeostasis and arrhythmias. In cardiac myocytes, RyRs are found in clusters of various sizes and shapes, and RyR cluster size may critically influence normal and arrhythmogenic Ca2+ spark and wave formation. However, the actual RyR cluster sizes at specific Ca2+ spark sites have never been measured in the physiological setting. METHODS AND RESULTS Here we measured RyR cluster size and Ca2+ sparks simultaneously to assess how RyR cluster size influences Ca2+ sparks and sarcoplasmic reticulum Ca2+ leak. For small RyR cluster sizes (<50), Ca2+ spark frequency is very low but then increases dramatically at larger cluster sizes. In contrast, Ca2+ spark amplitude is nearly maximal even at relatively small RyR cluster size (≈10) and changes little at larger cluster size. These properties agreed with computational simulations of RyR gating within clusters. CONCLUSIONS Our study explains how this combination of properties may limit arrhythmogenic Ca2+ sparks and wave propagation (at many junctions) while preserving the efficacy and spatial synchronization of Ca2+-induced Ca2+-release during normal excitation-contraction coupling. However, variations in RyR cluster size among individual junctions and RyR sensitivity could exacerbate heterogeneity of local sarcoplasmic reticulum Ca2+ release and arrhythmogenesis under pathological conditions.
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Affiliation(s)
- Samuel Galice
- Department of Pharmacology, University of California Davis, Davis, CA
| | - Yuanfang Xie
- Department of Pharmacology, University of California Davis, Davis, CA
| | - Yi Yang
- Department of Pharmacology, University of California Davis, Davis, CA
| | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, CA
| | - Donald M Bers
- Department of Pharmacology, University of California Davis, Davis, CA
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36
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Yang J, Zhang R, Jiang X, Lv J, Li Y, Ye H, Liu W, Wang G, Zhang C, Zheng N, Dong M, Wang Y, Chen P, Santosh K, Jiang Y, Liu J. Toll-like receptor 4-induced ryanodine receptor 2 oxidation and sarcoplasmic reticulum Ca 2+ leakage promote cardiac contractile dysfunction in sepsis. J Biol Chem 2017; 293:794-807. [PMID: 29150444 DOI: 10.1074/jbc.m117.812289] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/03/2017] [Indexed: 12/22/2022] Open
Abstract
Studies suggest the potential role of a sarcoplasmic reticulum (SR) Ca2+ leak in cardiac contractile dysfunction in sepsis. However, direct supporting evidence is lacking, and the mechanisms underlying this SR leak are poorly understood. Here, we investigated the changes in cardiac Ca2+ handling and contraction in LPS-treated rat cardiomyocytes and a mouse model of polymicrobial sepsis produced by cecal ligation and puncture (CLP). LPS decreased the systolic Ca2+ transient and myocyte contraction as well as SR Ca2+ content. Meanwhile, LPS increased Ca2+ spark-mediated SR Ca2+ leak. Preventing the SR leak with ryanodine receptor (RyR) blocker tetracaine restored SR load and increased myocyte contraction. Similar alterations in Ca2+ handling were observed in cardiomyocytes from CLP mice. Treatment with JTV-519, an anti-SR leak drug, restored Ca2+ handling and improved cardiac function. In the LPS-treated cardiomyocytes, mitochondrial reactive oxygen species and oxidative stress in RyR2 were increased, whereas the levels of the RyR2-associated FK506-binding protein 1B (FKBP12.6) were decreased. The Toll-like receptor 4 (TLR4)-specific inhibitor TAK-242 reduced the oxidative stress in LPS-treated cells, decreased the SR leak, and normalized Ca2+ handling and myocyte contraction. Consistently, TLR4 deletion significantly improved cardiac function and corrected abnormal Ca2+ handling in the CLP mice. This study provides evidence for the critical role of the SR Ca2+ leak in the development of septic cardiomyopathy and highlights the therapeutic potential of JTV-519 by preventing SR leak. Furthermore, it reveals that TLR4 activation-induced mitochondrial reactive oxygen species production and the resulting oxidative stress in RyR2 contribute to the SR Ca2+ leak.
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Affiliation(s)
- Jie Yang
- From the Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China.,the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Rui Zhang
- From the Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China
| | - Xin Jiang
- the Department of Cardiology, Second Affiliated Hospital of Jinan University (Shenzhen People's Hospital), Shenzhen 518000, China
| | - Jingzhang Lv
- the Shenzhen Entry-Exit Inspection and Quarantine Bureau, Shenzhen 518045, China, and
| | - Ying Li
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Hongyu Ye
- the Department of Cardiothoracic Surgery, Zhongshan People's Hospital, Zhongshan 528415, China
| | - Wenjuan Liu
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Gang Wang
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Cuicui Zhang
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Na Zheng
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Ming Dong
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Yan Wang
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Peiya Chen
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Kumar Santosh
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Yong Jiang
- From the Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China,
| | - Jie Liu
- From the Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China, .,the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
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37
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Zhao YT, Guo YB, Fan XX, Yang HQ, Zhou P, Chen Z, Yuan Q, Ye H, Ji GJ, Wang SQ. Role of FK506-binding protein in Ca 2+ spark regulation. Sci Bull (Beijing) 2017; 62:1295-1303. [PMID: 36659291 DOI: 10.1016/j.scib.2017.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/06/2017] [Accepted: 09/08/2017] [Indexed: 01/21/2023]
Abstract
The elementary Ca2+ release events, Ca2+ sparks, has been found for a quarter of century. However, the molecular regulation of the spark generator, the ryanodine receptor (RyR) on the sarcoplasmic reticulum, remains obscure. Although each subunit of the RyR homotetramer has a site for FK506-binding protein (FKBP), the role of FKBPs in modifying RyR Ca2+ sparks has been debated for long. One of the reasons behind the controversy is that most previous studies detect spontaneous sparks, where the mixture with out-of-focus events and local wavelets prevents an accurate characterization of Ca2+ sparks. In the present study, we detected Ca2+ sparks triggered by single L-type Ca2+ channels (LCCs) under loose-seal patch clamp conditions in FK506-treated or FKBP12.6 knockout cardiomyocytes. We found that FKBP dissociation both by FK506 and by rapamycin decreased the Ca2+ spark amplitude in ventricular cardiomyocytes. This change was neither due to decreased releasable Ca2+ in the sarcoplasmic reticulum, nor explained by changed RyR sensitivity. Actually FK506 increased the LCC-RyR coupling probability and curtailed the latency for an LCC to trigger a RyR Ca2+ spark. FKBP12.6 knockout had similar effects as FK506/rapamycin treatment, indicating that the decreased spark amplitude was attributable to the dissociation of FKBP12.6 rather than FKBP12. We also explained how decreased amplitude of spontaneous sparks after FKBP dissociation sometimes appears to be increased or unchanged due to inappropriate data processing. Our results provided firm evidence that without the inter-RyR coordination by functional FKBP12.6, the RyR recruitment during a Ca2+ spark would be compromised despite the sensitization of individual RyRs.
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Affiliation(s)
- Yan-Ting Zhao
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Yun-Bo Guo
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Xue-Xin Fan
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Hua-Qian Yang
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Peng Zhou
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Zheng Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Qi Yuan
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Haihong Ye
- School of Basic Medical Sciences, Beijing Institute for Brain Disorders Center of Schizophrenia, Capital Medical University, Beijing 100069, China
| | - Guang-Ju Ji
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Shi-Qiang Wang
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China.
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38
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Zhao YT, Guo YB, Gu L, Fan XX, Yang HQ, Chen Z, Zhou P, Yuan Q, Ji GJ, Wang SQ. Sensitized signalling between L-type Ca2+ channels and ryanodine receptors in the absence or inhibition of FKBP12.6 in cardiomyocytes. Cardiovasc Res 2017; 113:332-342. [PMID: 28077437 DOI: 10.1093/cvr/cvw247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 12/03/2016] [Indexed: 12/19/2022] Open
Abstract
Aims The heart contraction is controlled by the Ca2+-induced Ca2+ release (CICR) between L-type Ca2+ channels and ryanodine receptors (RyRs). The FK506-binding protein FKBP12.6 binds to RyR subunits, but its role in stabilizing RyR function has been debated for long. Recent reports of high-resolution RyR structure show that the HD2 domain that binds to the SPRY2 domain of neighbouring subunit in FKBP-bound RyR1 is detached and invisible in FKBP-null RyR2. The present study was to test the consequence of FKBP12.6 absence on the in situ activation of RyR2. Methods and results Using whole-cell patch-clamp combined with confocal imaging, we applied a near threshold depolarization to activate a very small fraction of LCCs, which in turn activated RyR Ca2+ sparks stochastically. FKBP12.6-knockout and FK506/rapamycin treatments increased spark frequency and LCC-RyR coupling fidelity without altering LCC open probability. Neither FK506 nor rapamycin further altered LCC-RyR coupling fidelity in FKBP12.6-knockout cells. In loose-seal patch-clamp experiments, the LCC-RyR signalling kinetics, indexed by the delay for a LCC sparklet to trigger a RyR spark, was accelerated after FKBP12.6 knockout and FK506/rapamycin treatments. These results demonstrated that RyRs became more sensitive to Ca2+ triggers without FKBP12.6. Isoproterenol (1 μM) further accelerated the LCC-RyR signalling in FKBP12.6-knockout cells. The synergistic sensitization of RyRs by catecholaminergic signalling and FKBP12.6 dysfunction destabilized the CICR system, leading to chaotic Ca2+ waves and ventricular arrhythmias. Conclusion FKBP12.6 keeps the RyRs from over-sensitization, stabilizes the potentially regenerative CICR system, and thus may suppress the life-threatening arrhythmogenesis.
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Affiliation(s)
- Yan-Ting Zhao
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China
| | - Yun-Bo Guo
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China
| | - Lei Gu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Xue-Xin Fan
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China
| | - Hua-Qian Yang
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China
| | - Zheng Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Peng Zhou
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China
| | - Qi Yuan
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Guang-Ju Ji
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Shi-Qiang Wang
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China
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39
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Walweel K, Oo YW, Laver DR. The emerging role of calmodulin regulation of RyR2 in controlling heart rhythm, the progression of heart failure and the antiarrhythmic action of dantrolene. Clin Exp Pharmacol Physiol 2017; 44:135-142. [PMID: 27626620 DOI: 10.1111/1440-1681.12669] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/27/2016] [Accepted: 09/09/2016] [Indexed: 11/28/2022]
Abstract
Cardiac output and rhythm depend on the release and the take-up of calcium from the sarcoplasmic reticulum (SR). Excessive diastolic calcium leak from the SR due to dysfunctional calcium release channels (RyR2) contributes to the formation of delayed after-depolarizations, which underlie the fatal arrhythmias that occur in heart failure and inherited syndromes. Calmodulin (CaM) is a calcium-binding protein that regulates target proteins and acts as a calcium sensor. CaM is comprised of two calcium-binding EF-hand domains and a flexible linker. CaM is an accessory protein that partially inhibits RyR2 channel activity. CaM is critical for normal cardiac function, and altered CaM binding and efficacy may contribute to defects in SR calcium release. The present paper reviews CaM binding to RyR2 and how it regulates RyR2 channel activity. It then goes on to review how mutations in the CaM amino acid sequence give rise to inherited syndromes such as Catecholaminergic Polymorphic Ventricular Tachychardia (CPVT) and long QT syndrome (LQTS). In addition, the role of reduced CaM binding to RyR2 that results from RyR2 phosphorylation or from oxidation of either RyR2 or CaM contributes to the progression of heart failure is reviewed. Finally, this manuscript reviews recent evidence that CaM binding to RyR2 is required for the inhibitory action of a pharmaceutical agent (dantrolene) on RyR2. Dantrolene is a clinically used muscle relaxant that has recently been found to exert antiarrhythmic effects against SR Ca2+ overload arrhythmias.
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Affiliation(s)
- Kafa Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| | - Ye Win Oo
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| | - Derek R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
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40
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Richardson SJ, Steele GA, Gallant EM, Lam A, Schwartz CE, Board PG, Casarotto MG, Beard NA, Dulhunty AF. Association of FK506 binding proteins with RyR channels - effect of CLIC2 binding on sub-conductance opening and FKBP binding. J Cell Sci 2017; 130:3588-3600. [PMID: 28851804 DOI: 10.1242/jcs.204461] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 07/31/2017] [Indexed: 12/22/2022] Open
Abstract
Ryanodine receptor (RyR) Ca2+ channels are central to striated muscle function and influence signalling in neurons and other cell types. Beneficially low RyR activity and maximum conductance opening may be stabilised when RyRs bind to FK506 binding proteins (FKBPs) and destabilised by FKBP dissociation, with submaximal opening during RyR hyperactivity associated with myopathies and neurological disorders. However, the correlation with submaximal opening is debated and quantitative evidence is lacking. Here, we have measured altered FKBP binding to RyRs and submaximal activity with addition of wild-type (WT) CLIC2, an inhibitory RyR ligand, or its H101Q mutant that hyperactivates RyRs, which probably causes cardiac and intellectual abnormalities. The proportion of sub-conductance opening increases with WT and H101Q CLIC2 and is correlated with reduced FKBP-RyR association. The sub-conductance opening reduces RyR currents in the presence of WT CLIC2. In contrast, sub-conductance openings contribute to excess RyR 'leak' with H101Q CLIC2. There are significant FKBP and RyR isoform-specific actions of CLIC2, rapamycin and FK506 on FKBP-RyR association. The results show that FKBPs do influence RyR gating and would contribute to excess Ca2+ release in this CLIC2 RyR channelopathy.
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Affiliation(s)
- Spencer J Richardson
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
| | - Gregory A Steele
- Capital Pathology Laboratory, 70 Kent St, Deakin, ACT 2600, Australia
| | - Esther M Gallant
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
| | - Alexander Lam
- Neurosurgery, Royal Perth Hospital, 197 Wellington St, Perth, WA 6000, Australia
| | - Charles E Schwartz
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Philip G Board
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
| | - Marco G Casarotto
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
| | - Nicole A Beard
- Cardiac Physiology Department, Health Research Institute, Faculty of Education Science and Mathematics, University of Canberra, Bruce, ACT 2617, Australia
| | - Angela F Dulhunty
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, PO Box 334, ACT 2601, Australia
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41
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Abstract
Cardiac contractility is regulated by changes in intracellular Ca concentration ([Ca2+]i). Normal function requires that [Ca2+]i be sufficiently high in systole and low in diastole. Much of the Ca needed for contraction comes from the sarcoplasmic reticulum and is released by the process of calcium-induced calcium release. The factors that regulate and fine-tune the initiation and termination of release are reviewed. The precise control of intracellular Ca cycling depends on the relationships between the various channels and pumps that are involved. We consider 2 aspects: (1) structural coupling: the transporters are organized within the dyad, linking the transverse tubule and sarcoplasmic reticulum and ensuring close proximity of Ca entry to sites of release. (2) Functional coupling: where the fluxes across all membranes must be balanced such that, in the steady state, Ca influx equals Ca efflux on every beat. The remainder of the review considers specific aspects of Ca signaling, including the role of Ca buffers, mitochondria, Ca leak, and regulation of diastolic [Ca2+]i.
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Affiliation(s)
- David A Eisner
- From the Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, United Kingdom.
| | - Jessica L Caldwell
- From the Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, United Kingdom
| | - Kornél Kistamás
- From the Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, United Kingdom
| | - Andrew W Trafford
- From the Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, United Kingdom
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42
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Jones PP, Guo W, Chen SRW. Control of cardiac ryanodine receptor by sarcoplasmic reticulum luminal Ca 2. J Gen Physiol 2017; 149:867-875. [PMID: 28798281 PMCID: PMC5583710 DOI: 10.1085/jgp.201711805] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 06/25/2017] [Accepted: 07/18/2017] [Indexed: 12/22/2022] Open
Abstract
Jones et al. propose that SR luminal Ca2+ regulates RyR2 activity via a luminal Ca2+ sensor distinct from the cytosolic Ca2+ sensor.
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Affiliation(s)
- Peter P Jones
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, Otago, New Zealand .,HeartOtago, University of Otago, Dunedin, Otago, New Zealand
| | - Wenting Guo
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - S R Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
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43
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Cannell MB, Kong CHT. Quenching the spark: Termination of CICR in the submicroscopic space of the dyad. J Gen Physiol 2017; 149:837-845. [PMID: 28798280 PMCID: PMC5583711 DOI: 10.1085/jgp.201711807] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 07/21/2017] [Indexed: 12/20/2022] Open
Abstract
Cannell and Kong discuss the different termination mechanisms proposed for CICR in cardiac myocytes.
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Affiliation(s)
- Mark B Cannell
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, England, UK
| | - Cherrie H T Kong
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, England, UK
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44
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Pahlavan S, Morad M. Total internal reflectance fluorescence imaging of genetically engineered ryanodine receptor-targeted Ca 2+ probes in rat ventricular myocytes. Cell Calcium 2017; 66:98-110. [PMID: 28807154 DOI: 10.1016/j.ceca.2017.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 12/11/2022]
Abstract
The details of cardiac Ca2+ signaling within the dyadic junction remain unclear because of limitations in rapid spatial imaging techniques, and availability of Ca2+ probes localized to dyadic junctions. To critically monitor ryanodine receptors' (RyR2) Ca2+ nano-domains, we combined the use of genetically engineered RyR2-targeted pericam probes, (FKBP-YCaMP, Kd=150nM, or FKBP-GCaMP6, Kd=240nM) with rapid total internal reflectance fluorescence (TIRF) microscopy (resolution, ∼80nm). The punctate z-line patterns of FKBP,2-targeted probes overlapped those of RyR2 antibodies and sharply contrasted to the images of probes targeted to sarcoplasmic reticulum (SERCA2a/PLB), or cytosolic Fluo-4 images. FKBP-YCaMP signals were too small (∼20%) and too slow (2-3s) to detect Ca2+ sparks, but the probe was effective in marking where Fluo-4 Ca2+ sparks developed. FKBP-GCaMP6, on the other hand, produced rapidly decaying Ca2+ signals that: a) had faster kinetics and activated synchronous with ICa3 but were of variable size at different z-lines and b) were accompanied by spatially confined spontaneous Ca2+ sparks, originating from a subset of eager sites. The frequency of spontaneously occurring sparks was lower in FKBP-GCaMP6 infected myocytes as compared to Fluo-4 dialyzed myocytes, but isoproterenol enhanced their frequency more effectively than in Fluo-4 dialyzed cells. Nevertheless, isoproterenol failed to dissociate FKBP-GCaMP6 from the z-lines. The data suggests that FKBP-GCaMP6 binds predominantly to junctional RyR2s and has sufficient on-rate efficiency as to monitor the released Ca2+ in individual dyadic clefts, and supports the idea that β-adrenergic agonists may modulate the stabilizing effects of native FKBP on RyR2.
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Affiliation(s)
- Sara Pahlavan
- Cardiac Signaling Center of University of South Carolina, Clemson University and Medical University of South Carolina, Charleston, SC 29425, USA.
| | - Marin Morad
- Cardiac Signaling Center of University of South Carolina, Clemson University and Medical University of South Carolina, Charleston, SC 29425, USA.
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45
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Gonano LA, Jones PP. FK506-binding proteins 12 and 12.6 (FKBPs) as regulators of cardiac Ryanodine Receptors: Insights from new functional and structural knowledge. Channels (Austin) 2017. [PMID: 28636428 DOI: 10.1080/19336950.2017.1344799] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Ryanodine Receptors (RyRs) are intracellular Ca2+ channels that mediate Ca2+ flux from the sarco(endo)plasmic reticulum in many cell types. The interaction of RyRs with FK506-binding proteins (FKBPs) has been proposed as an important regulatory mechanism, where the loss of this interaction leads to channel dysfunction. In the heart, phosphorylation of RyR has been suggested to disrupt the RyR-FKBP interaction promoting altered Ca2+ signaling, heart failure and arrhythmias. However, the functional result of FKBP interaction with RyR and how this interaction is regulated remains highly controversial. Recently, high resolution structures of RyR have provided novel aspects to the ongoing debate. This review will discuss the most recent functional data in light of these new structures.
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Affiliation(s)
- Luis A Gonano
- a Department of Physiology , School of Biomedical Sciences and HeartOtago, University of Otago , Dunedin, Otago , New Zealand
| | - Peter P Jones
- a Department of Physiology , School of Biomedical Sciences and HeartOtago, University of Otago , Dunedin, Otago , New Zealand
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46
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Cabra V, Murayama T, Samsó M. Ultrastructural Analysis of Self-Associated RyR2s. Biophys J 2017; 110:2651-2662. [PMID: 27332123 DOI: 10.1016/j.bpj.2016.05.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/28/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022] Open
Abstract
In heart, type-2 ryanodine receptor (RyR2) forms discrete supramolecular clusters in the sarcoplasmic reticulum known as calcium release units (CRUs), which are responsible for most of the Ca(2+) released for muscle contraction. To learn about the substructure of the CRU, we sought to determine whether RyR2s have the ability to self-associate in the absence of other factors and if so, whether they do it in a specific manner. Purified RyR2 was negatively stained and imaged on the transmission electron microscope, and RyR2 particles closely associated were further analyzed using bias-free multivariate statistical analysis and classification. The resulting two-dimensional averages show that RyR2s can interact in two rigid, reproducible configurations: "adjoining", with two RyR2s alongside each other, and "oblique", with two partially overlapped RyR2s forming an angle of 12°. The two configurations are nearly identical under two extreme physiological Ca(2+) concentrations. Pseudo-atomic models for these two interactions indicate that the adjoining interaction involves contacts between the P1, SPRY1 and the helical domains. The oblique interaction is mediated by extensive contacts between the SPRY1 domains (domains 9) and P1 domains (domains 10) of both RyR2s and not through domain 6 as previously thought; in addition its asymmetric interface imposes steric constrains that inhibit the growth of RyR2 as a checkerboard, which is the configuration usually assumed, and generates new configurations, i.e., "branched" and "interlocked". This first, to our knowledge, structural detailed analysis of the inter-RyR2 interactions helps to understand important morphological and functional aspects of the CRU in the context of cardiac EC coupling.
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Affiliation(s)
- Vanessa Cabra
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia
| | - Takashi Murayama
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Montserrat Samsó
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia.
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47
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Liu ZY, Huang J, Liu NN, Zheng M, Zhao T, Zhao BC, Wang YM, Pu JL. Molecular Mechanisms of Increased Heart Rate in Shenxianshengmai-treated Bradycardia Rabbits. Chin Med J (Engl) 2017; 130:179-186. [PMID: 28091410 PMCID: PMC5282675 DOI: 10.4103/0366-6999.197999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background: The molecular mechanisms of Shenxianshengmai (SXSM), a traditional Chinese medicine, on bradycardia have been incompletely understood. The study tried to investigate the gene expression profile and proteomics of bradycardia rabbits’ hearts after SXSM treatment. Methods: Twenty-four adult rabbits were randomly assigned in four groups: sham, model, model plus SXSM treatment, and sham plus SXSM treatment groups. Heart rate was recorded in all rabbits. Then, total RNA of atria and proteins of ventricle were isolated and quantified, respectively. Gene expression profiling was conducted by gene expression chip, and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) was performed to confirm the results of gene expression chip. We used isobaric tags for elative and absolute quantitation and Western blotting to identify altered proteins after SXSM treatment. Results: There was a constant decrease in the mean heart rate (32%, from 238 ± 6 beats/min to 149 ± 12 beats/min) after six weeks in model compared with that in sham group. This effect was partially reversed by 4-week SXSM treatment. Complementary DNA microarray demonstrated that the increased acetylcholinesterase and reduced nicotinic receptor were take responsibility for the increased heart rate. In addition, proteins involved in calcium handling and signaling were affected by SXSM treatment. Real-time RT-PCR verified the results from gene chip. Results from proteomics demonstrated that SXSM enhanced oxidative phosphorylation and tricarboxylic acid (TCA) cycle in ventricular myocardium to improve ATP generation. Conclusions: Long-term SXSM stimulates sympathetic transmission by increasing the expression of acetylcholinesterase and reduces the expression of nicotinic receptor to increase heart rate. SXSM also restored the calcium handling genes and altered genes involved in signaling. In addition, SXSM improves the ATP supply of ventricular myocardium by increasing proteins involved in TCA cycle and oxidation-respiratory chain.
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Affiliation(s)
- Zhou-Ying Liu
- State Key Laboratory of Translational Cardiovascular Medicine, Fuwai Hospital and Cardiovascular Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037; Department of Pathology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
| | - Jian Huang
- State Key Laboratory of Translational Cardiovascular Medicine, Fuwai Hospital and Cardiovascular Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Na-Na Liu
- State Key Laboratory of Translational Cardiovascular Medicine, Fuwai Hospital and Cardiovascular Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Min Zheng
- State Key Laboratory of Translational Cardiovascular Medicine, Fuwai Hospital and Cardiovascular Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Tao Zhao
- Shandong Buchang Pharmaceutical Co. Ltd., Heze, Shandong 274003, China
| | - Bu-Chang Zhao
- Shandong Buchang Pharmaceutical Co. Ltd., Heze, Shandong 274003, China
| | - Yi-Min Wang
- Shandong Buchang Pharmaceutical Co. Ltd., Heze, Shandong 274003, China
| | - Jie-Lin Pu
- State Key Laboratory of Translational Cardiovascular Medicine, Fuwai Hospital and Cardiovascular Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
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Walweel K, Molenaar P, Imtiaz MS, Denniss A, Dos Remedios C, van Helden DF, Dulhunty AF, Laver DR, Beard NA. Ryanodine receptor modification and regulation by intracellular Ca 2+ and Mg 2+ in healthy and failing human hearts. J Mol Cell Cardiol 2017; 104:53-62. [PMID: 28131631 DOI: 10.1016/j.yjmcc.2017.01.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 01/01/2017] [Accepted: 01/24/2017] [Indexed: 11/30/2022]
Abstract
RATIONALE Heart failure is a multimodal disorder, of which disrupted Ca2+ homeostasis is a hallmark. Central to Ca2+ homeostasis is the major cardiac Ca2+ release channel - the ryanodine receptor (RyR2) - whose activity is influenced by associated proteins, covalent modification and by Ca2+ and Mg2+. That RyR2 is remodelled and its function disturbed in heart failure is well recognized, but poorly understood. OBJECTIVE To assess Ca2+ and Mg2+ regulation of RyR2 from left ventricles of healthy, cystic fibrosis and failing hearts, and to correlate these functional changes with RyR2 modifications and remodelling. METHODS AND RESULTS The function of RyR2 from left ventricular samples was assessed using lipid bilayer single-channel measurements, whilst RyR2 modification and protein:protein interactions were determined using Western Blots and co-immunoprecipitation. In all failing hearts there was an increase in RyR2 activity at end-diastolic cytoplasmic Ca2+ (100nM), a decreased cytoplasmic [Ca2+] required for half maximal activation (Ka) and a decrease in inhibition by cytoplasmic Mg2+. This was accompanied by significant hyperphosphorylation of RyR2 S2808 and S2814, reduced free thiol content and a reduced interaction with FKBP12.0 and FKBP12.6. Either dephosphorylation of RyR2 using PP1 or thiol reduction using DTT eliminated any significant difference in the activity of RyR2 from healthy and failing hearts. We also report a subgroup of RyR2 in failing hearts that were not responsive to regulation by intracellular Ca2+ or Mg2+. CONCLUSION Despite different aetiologies, disrupted RyR2 Ca2+ sensitivity and biochemical modification of the channel are common constituents of failing heart RyR2 and may underlie the pathological disturbances in intracellular Ca2+ signalling.
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Affiliation(s)
- K Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW 2308, Australia
| | - P Molenaar
- Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, 4000, Northside Clinical School, School of Clinical Medicine, University of Queensland and Critical Care Research Group, The Prince Charles Hospital, Chermside, QLD, 4032, Australia
| | - M S Imtiaz
- Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
| | - A Denniss
- Health Research Institute, Faculty of Education Science and Mathematics, University of Canberra, Bruce, ACT 2617, Australia
| | - C Dos Remedios
- Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales 2006, Australia
| | - D F van Helden
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW 2308, Australia
| | - A F Dulhunty
- John Curtin School of Medical Research, Australian National University, Canberra, ACT, 0200, Australia
| | - D R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW 2308, Australia
| | - N A Beard
- Health Research Institute, Faculty of Education Science and Mathematics, University of Canberra, Bruce, ACT 2617, Australia; John Curtin School of Medical Research, Australian National University, Canberra, ACT, 0200, Australia.
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Dulhunty AF, Board PG, Beard NA, Casarotto MG. Physiology and Pharmacology of Ryanodine Receptor Calcium Release Channels. ADVANCES IN PHARMACOLOGY 2017; 79:287-324. [DOI: 10.1016/bs.apha.2016.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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