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Yang Z, Yue Z, Ma X, Xu Z. Calcium Homeostasis: A Potential Vicious Cycle of Bone Metastasis in Breast Cancers. Front Oncol 2020; 10:293. [PMID: 32211326 PMCID: PMC7076168 DOI: 10.3389/fonc.2020.00293] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
Cancers have been considered as one of the most severe health problems in the world. Efforts to elucidate the cancer progression reveal the importance of bone metastasis for tumor malignancy, one of the leading causes for high mortality rate. Multiple cancers develop bone metastasis, from which breast cancers exhibit the highest rate and have been well-recognized. Numerous cells and environmental factors have been believed to synergistically facilitate bone metastasis in breast cancers, from which breast cancer cells, osteoclasts, osteoblasts, and their produced cytokines have been well-recognized to form a vicious cycle that aggravates tumor malignancy. Except the cytokines or chemokines, calcium ions are another element largely released from bones during bone metastasis that leads to hypercalcemia, however, have not been well-characterized yet in modulation of bone metastasis. Calcium ions act as a type of unique second messenger that exhibits omnipotent functions in numerous cells, including tumor cells, osteoclasts, and osteoblasts. Calcium ions cannot be produced in the cells and are dynamically fluxed among extracellular calcium pools, intracellular calcium storages and cytosolic calcium signals, namely calcium homeostasis, raising a possibility that calcium ions released from bone during bone metastasis would further enhance bone metastasis and aggravate tumor progression via the vicious cycle due to abnormal calcium homeostasis in breast cancer cells, osteoclasts and osteoblasts. TRPs, VGCCs, SOCE, and P2Xs are four major calcium channels/routes mediating extracellular calcium entry and affect calcium homeostasis. Here we will summarize the overall functions of these four calcium channels in breast cancer cells, osteoclasts and osteoblasts, providing evidence of calcium homeostasis as a vicious cycle in modulation of bone metastasis in breast cancers.
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Affiliation(s)
- Zhengfeng Yang
- Shanghai Institute of Immunology Center for Microbiota & Immune Related Diseases, Institute of Translational Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhiying Yue
- Department of Urology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xinrun Ma
- Shanghai Institute of Immunology Center for Microbiota & Immune Related Diseases, Institute of Translational Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhenyao Xu
- Shanghai Institute of Immunology Center for Microbiota & Immune Related Diseases, Institute of Translational Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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102
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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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103
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Solorza J, Recabarren R, Alzate-Morales J. Molecular Insights into the Trapping Effect of Ca 2+ in Protein Kinase A: A Molecular Dynamics Study. J Chem Inf Model 2020; 60:898-914. [PMID: 31804819 DOI: 10.1021/acs.jcim.9b00857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Protein kinase A has become a model system for the study of kinases, and therefore, a comprehensive understanding of the underlying molecular mechanisms in its catalytic cycle is of crucial importance. One of the aspects that has received recent attention is the role that metal cofactors play in the catalytic cycle. Although Mg2+ is the well-known physiological ion used by protein kinases, Ca2+ ions can also assist the phosphoryl transfer reaction but with lower catalytic activities. This inhibitory effect has been attributed to the ability of Ca2+ to trap the reaction products at the active site, and it has been proposed as a possible regulatory mechanism of the enzyme. Thus, in order to get a clearer understanding of these molecular events, computational simulations in the product state of PKA, in the presence of Mg2+ and Ca2+ ions, were performed through molecular dynamics (MD). Different protonation states of the active site were considered in order to model the different mechanistic pathways that have been proposed. Our results show that different protonation states of the phosphorylated serine residue at the peptide substrate (pSer21), as well as the protonation state of residue Asp166, can have a marked influence on the flexibility of regions surrounding the active site. This is the case of the glycine-rich loop, a structural motif that is directly involved in the release of the products from the PKA active site. MD simulations were capable to reproduce the crystallographic conformations but also showed other conformations not previously reported in the crystal structures that may be involved in enhancing the affinity of pSP20 to PKA in the presence of Ca2+. Hydrogen bonding interactions at the PKA-pSP20 interface were influenced whether by the protonation state of the active site or by the metal cofactor used by the enzyme. Altogether, our results provide molecular aspects into the inhibitory mechanism of Ca2+ in PKA and suggest which is the most probable protonation state of the phosphorylated product at the active site.
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Affiliation(s)
- Jocelyn Solorza
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería , Universidad de Talca , 1 Poniente 1141 , Talca , Chile
| | - Rodrigo Recabarren
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería , Universidad de Talca , 1 Poniente 1141 , Talca , Chile
| | - Jans Alzate-Morales
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería , Universidad de Talca , 1 Poniente 1141 , Talca , Chile
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104
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Chen HH, Wang SN, Cao TT, Zheng JL, Tian J, Shan XL, Zhao P, Guo W, Xu M, Zhang C, Lu R. Stachydrine hydrochloride alleviates pressure overload-induced heart failure and calcium mishandling on mice. JOURNAL OF ETHNOPHARMACOLOGY 2020; 248:112306. [PMID: 31626909 DOI: 10.1016/j.jep.2019.112306] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 09/16/2019] [Accepted: 10/12/2019] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Traditional Chinese medicine Leonurus japonicus Houtt. has a long history in the treatment of cardiovascular diseases. Stachydrine hydrochloride, the main bioactive ingredient extracted from Leonurus japonicus Houtt., has been shown to have cardioprotective effects. However, the underlying mechanisms of stachydrine hydrochloride haven't been comprehensively studied so far. AIM OF THE STUDY The aim of this study was to investigate the protective role of stachydrine hydrochloride in heart failure and elucidate its possible mechanisms of action. MATERIALS AND METHODS In vivo, transverse aorta constriction was carried out in C57BL/6J mice, and thereafter, 7.2 mg/kg telmisartan (a selective AT1R antagonist as positive control) and 12 mg/kg stachydrine hydrochloride was administered daily intragastrically for 4 weeks. Cardiac function was evaluated by assessing morphological changes as well as echocardiographic and haemodynamic parameters. In vitro, neonatal rat cardiomyocytes or adult mice cardiomyocytes were treated with stachydrine hydrochloride and challenged with phenylephrine (α-AR agonist). Ventricular myocytes were isolated from the hearts of C57BL/6J mice by Langendorff crossflow perfusion system. Intracellular calcium was measured by an ion imaging system. The length and movement of sarcomere were traced to evaluate the systolic and diastolic function of single myocardial cells. RESULTS Stachydrine hydrochloride improved the cardiac function and calcium transient amplitudes, and inhibited the SR leakage and the amount of sparks in cardiac myocytes isolated from TAC mice. We also demonstrated that stachydrine hydrochloride could ameliorated phenylephrine-induced enhance in sarcomere contraction, calcium transients and calcium sparks. Moreover, our data shown that stachydrine hydrochloride blocked the hyper-phosphorylation of CaMKII, RyR2, PLN, and prevented the disassociation of FKBP12.6 from RyR2. CONCLUSION Our results suggest that stachydrine hydrochloride exerts beneficial therapeutic effects against heart failure. These cardioprotective effects may be associated with the regulation of calcium handling by stachydrine hydrochloride through inhibiting the hyper-phosphorylation of CaMKII.
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Affiliation(s)
- Hui-Hua Chen
- School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Si-Ning Wang
- School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | | | - Jia-Li Zheng
- School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Jing Tian
- School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Xiao-Li Shan
- Public Laboratory Platform, School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Pei Zhao
- Public Laboratory Platform, School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Wei Guo
- Department of Pathology, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Ming Xu
- Department of Physiology, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Chen Zhang
- Department of Pathology, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Rong Lu
- School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
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105
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Song Z, Xie LH, Weiss JN, Qu Z. A Spatiotemporal Ventricular Myocyte Model Incorporating Mitochondrial Calcium Cycling. Biophys J 2019; 117:2349-2360. [PMID: 31623883 PMCID: PMC6990377 DOI: 10.1016/j.bpj.2019.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/19/2019] [Accepted: 09/09/2019] [Indexed: 12/27/2022] Open
Abstract
Intracellular calcium (Ca2+) cycling dynamics in cardiac myocytes are spatiotemporally generated by stochastic events arising from a spatially distributed network of coupled Ca2+ release units that interact with an intertwined mitochondrial network. In this study, we developed a spatiotemporal ventricular myocyte model that integrates mitochondria-related Ca2+ cycling components into our previously developed ventricular myocyte model consisting of a three-dimensional Ca2+ release unit network. Mathematical formulations of mitochondrial membrane potential, mitochondrial Ca2+ cycling, mitochondrial permeability transition pore stochastic opening and closing, intracellular reactive oxygen species signaling, and oxidized Ca2+/calmodulin-dependent protein kinase II signaling were incorporated into the model. We then used the model to simulate the effects of mitochondrial depolarization on mitochondrial Ca2+ cycling, Ca2+ spark frequency, and Ca2+ amplitude, which agree well with experimental data. We also simulated the effects of the strength of mitochondrial Ca2+ uniporters and their spatial localization on intracellular Ca2+ cycling properties, which substantially affected diastolic and systolic Ca2+ levels in the mitochondria but exhibited only a small effect on sarcoplasmic reticulum and cytosolic Ca2+ levels under normal conditions. We show that mitochondrial depolarization can cause Ca2+ waves and Ca2+ alternans, which agrees with previous experimental observations. We propose that this new, to our knowledge, spatiotemporal ventricular myocyte model, incorporating properties of mitochondrial Ca2+ cycling and reactive-oxygen-species-dependent signaling, will be useful for investigating the effects of mitochondria on intracellular Ca2+ cycling and action potential dynamics in ventricular myocytes.
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Affiliation(s)
- Zhen Song
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, New Jersey
| | - James N Weiss
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Zhilin Qu
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Biomathematics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
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106
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Timmermann V, Edwards AG, Wall ST, Sundnes J, McCulloch AD. Arrhythmogenic Current Generation by Myofilament-Triggered Ca 2+ Release and Sarcomere Heterogeneity. Biophys J 2019; 117:2471-2485. [PMID: 31810659 PMCID: PMC6990379 DOI: 10.1016/j.bpj.2019.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 01/05/2023] Open
Abstract
Heterogeneous mechanical dyskinesis has been implicated in many arrhythmogenic phenotypes. Strain-dependent perturbations to cardiomyocyte electrophysiology may contribute to this arrhythmogenesis through processes referred to as mechanoelectric feedback. Although the role of stretch-activated ion currents has been investigated using computational models, experimental studies suggest that mechanical strain may also promote arrhythmia by facilitating calcium wave propagation. To investigate whether strain-dependent changes in calcium affinity to the myofilament may promote arrhythmogenic intracellular calcium waves, we modified a mathematical model of rabbit excitation-contraction coupling coupled to a model of myofilament activation and force development. In a one-dimensional compartmental analysis, we bidirectionally coupled 50 sarcomere models in series to model calcium diffusion and stress transfer between adjacent sarcomeres. These considerations enabled the model to capture 1) the effects of mechanical feedback on calcium homeostasis at the sarcomeric level and 2) the combined effects of mechanical and calcium heterogeneities at the cellular level. The results suggest that in conditions of calcium overload, the vulnerable window of stretch-release to trigger suprathreshold delayed afterdepolarizations can be affected by heterogeneity in sarcomere length. Furthermore, stretch and sarcomere heterogeneity may modulate the susceptibility threshold for delayed afterdepolarizations and the aftercontraction wave propagation velocity.
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Affiliation(s)
- Viviane Timmermann
- Simula Research Laboratory, Fornebu, Norway; University of Oslo, Oslo, Norway; University of California San Diego, La Jolla, California.
| | - Andrew G Edwards
- Simula Research Laboratory, Fornebu, Norway; University of Oslo, Oslo, Norway
| | | | - Joakim Sundnes
- University of Oslo, Oslo, Norway; University of California San Diego, La Jolla, California
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107
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Rethinking calcium profiles around single channels: the exponential and periodic calcium nanodomains. Sci Rep 2019; 9:17196. [PMID: 31748584 PMCID: PMC6868209 DOI: 10.1038/s41598-019-53095-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 10/24/2019] [Indexed: 11/25/2022] Open
Abstract
Many fundamental calcium-dependent physiological processes are triggered by high local calcium levels that are established around the sites of calcium entry into the cell (channels). They are dubbed as calcium nanodomains but their exact profiles are still elusive. The concept of calcium nanodomains stems from a linear model of calcium diffusion and is only valid when calcium increases are smaller than the concentration of cytoplasmic buffers. Recent data indicates that much higher calcium levels cause buffer saturation. Therefore, I sought explicit solutions of a nonlinear reaction-diffusion model and found a dichotomous solution. For small fluxes, the steady state calcium profile is quasi-exponential, and when calcium exceeds buffer concentration a spatial periodicity appears. Analytical results are supported by Monte-Carlo simulations. I also imaged 1D- and radial calcium distributions around single α-synuclein channels in cell-free conditions. Measured Ca profiles are consistent with theoretical predictions. I propose that the periodic calcium patterns may well arise under certain conditions and their specific functional role has to be established.
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108
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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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109
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Vierra NC, Kirmiz M, van der List D, Santana LF, Trimmer JS. Kv2.1 mediates spatial and functional coupling of L-type calcium channels and ryanodine receptors in mammalian neurons. eLife 2019; 8:49953. [PMID: 31663850 PMCID: PMC6839919 DOI: 10.7554/elife.49953] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/29/2019] [Indexed: 12/16/2022] Open
Abstract
The voltage-gated K+ channel Kv2.1 serves a major structural role in the soma and proximal dendrites of mammalian brain neurons, tethering the plasma membrane (PM) to endoplasmic reticulum (ER). Although Kv2.1 clustering at neuronal ER-PM junctions (EPJs) is tightly regulated and highly conserved, its function remains unclear. By identifying and evaluating proteins in close spatial proximity to Kv2.1-containing EPJs, we discovered that a significant role of Kv2.1 at EPJs is to promote the clustering and functional coupling of PM L-type Ca2+ channels (LTCCs) to ryanodine receptor (RyR) ER Ca2+ release channels. Kv2.1 clustering also unexpectedly enhanced LTCC opening at polarized membrane potentials. This enabled Kv2.1-LTCC-RyR triads to generate localized Ca2+ release events (i.e., Ca2+ sparks) independently of action potentials. Together, these findings uncover a novel mode of LTCC regulation and establish a unique mechanism whereby Kv2.1-associated EPJs provide a molecular platform for localized somatodendritic Ca2+ signals in mammalian brain neurons.
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Affiliation(s)
- Nicholas C Vierra
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - Michael Kirmiz
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - Deborah van der List
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States
| | - James S Trimmer
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
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110
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Dybkova N, Ahmad S, Pabel S, Tirilomis P, Hartmann N, Fischer TH, Bengel P, Tirilomis T, Ljubojevic S, Renner A, Gummert J, Ellenberger D, Wagner S, Frey N, Maier LS, Streckfuss-Bömeke K, Hasenfuss G, Sossalla S. Differential regulation of sodium channels as a novel proarrhythmic mechanism in the human failing heart. Cardiovasc Res 2019; 114:1728-1737. [PMID: 29931291 DOI: 10.1093/cvr/cvy152] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 06/15/2018] [Indexed: 12/18/2022] Open
Abstract
Aims In heart failure (HF), enhanced persistent Na+ current (INaL) exerts detrimental effects on cellular electrophysiology and can induce arrhythmias. However, the underlying regulatory mechanisms remain unclear. Our aim was to potentially investigate the regulation and electrophysiological contribution of neuronal sodium channel NaV1.8 in failing human heart and eventually to reveal a novel anti-arrhythmic therapy. Methods and results By western blot, we found that NaV1.8 protein expression is significantly up-regulated, while of the predominant cardiac isoform NaV1.5 is inversely reduced in human HF. Furthermore, to investigate the relation of NaV1.8 regulation with the cellular proarrhythmic events, we performed comprehensive electrophysiology recordings and explore the effect of NaV1.8 on INaL, action potential duration (APD), Ca2+ spark frequency, and arrhythmia induction in human failing cardiomyocytes. NaV1.8 inhibition with the specific blockers A-803467 and PF-01247324 decreased INaL, abbreviated APD and reduced cellular-spontaneous Ca2+-release and proarrhythmic events in human failing cardiomyocytes. Consistently, in mouse cardiomyocytes stressed with isoproterenol, pharmacologic inhibition and genetically knockout of NaV1.8 (SCN10A-/-), were associated with reduced INaL and abbreviated APD. Conclusion We provide first evidence of differential regulation of NaV1.8 and NaV1.5 in the failing human myocardium and their contribution to arrhythmogenesis due to generation of INaL. We propose inhibition of NaV1.8 thus constitutes a promising novel approach for selective anti-arrhythmic therapy in HF.
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Affiliation(s)
- Nataliya Dybkova
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Shakil Ahmad
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Steffen Pabel
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Petros Tirilomis
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Nico Hartmann
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Thomas H Fischer
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Philipp Bengel
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Theodoros Tirilomis
- Department of Thoracic, Cardiac and Vascular Surgery, Georg-August University Goettingen, Germany
| | | | - André Renner
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - Jan Gummert
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - David Ellenberger
- Department of Medical Statistics, University Medical Center Goettingen, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Norbert Frey
- Department of Internal Medicine III, Molecular Cardiology and Angiology, University Medical Center, Campus Kiel, Schleswig-Holstein, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Samuel Sossalla
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
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111
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Abstract
Regulation of ATP production by mitochondria, critical to multicellular life, is poorly understood. Here we investigate the molecular controls of this process in heart and provide a framework for its Ca2+-dependent regulation. We find that the entry of Ca2+ into the matrix through the mitochondrial calcium uniporter (MCU) in heart has neither an apparent cytosolic Ca2+ threshold nor gating function and guides ATP production by its influence on the inner mitochondrial membrane (IMM) potential, ΔΨm. This regulation occurs by matrix Ca2+-dependent modulation of pyruvate and glutamate dehydrogenase activity and not through any effect of Ca2+ on ATP Synthase or on Electron Transport Chain Complexes II, III or IV. Examining the ΔΨm dependence of ATP production over the range of -60 mV to -170 mV in detail reveals that cardiac ATP synthase has a voltage dependence that distinguishes it fundamentally from the previous standard, the bacterial ATP synthase. Cardiac ATP synthase operates with a different ΔΨm threshold for ATP production than bacterial ATP synthase and reveals a concave-upwards shape without saturation. Skeletal muscle MCU Ca2+ flux, while also having no apparent cytosolic Ca2+ threshold, is substantially different from the cardiac MCU, yet the ATP synthase voltage dependence in skeletal muscle is identical to that in the heart. These results suggest that while the conduction of cytosolic Ca2+ signals through the MCU appears to be tissue-dependent, as shown by earlier work1, the control of ATP synthase by ΔΨm appears to be broadly consistent among tissues but is clearly different from bacteria.
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Affiliation(s)
- Andrew P Wescott
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA.
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA.
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112
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Kushnir A, Santulli G, Reiken SR, Coromilas E, Godfrey SJ, Brunjes DL, Colombo PC, Yuzefpolskaya M, Sokol SI, Kitsis RN, Marks AR. Ryanodine Receptor Calcium Leak in Circulating B-Lymphocytes as a Biomarker in Heart Failure. Circulation 2019; 138:1144-1154. [PMID: 29593014 DOI: 10.1161/circulationaha.117.032703] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Advances in congestive heart failure (CHF) management depend on biomarkers for monitoring disease progression and therapeutic response. During systole, intracellular Ca2+ is released from the sarcoplasmic reticulum into the cytoplasm through type-2 ryanodine receptor/Ca2+ release channels. In CHF, chronically elevated circulating catecholamine levels cause pathological remodeling of type-2 ryanodine receptor/Ca2+ release channels resulting in diastolic sarcoplasmic reticulum Ca2+ leak and decreased myocardial contractility. Similarly, skeletal muscle contraction requires sarcoplasmic reticulum Ca2+ release through type-1 ryanodine receptors (RyR1), and chronically elevated catecholamine levels in CHF cause RyR1-mediated sarcoplasmic reticulum Ca2+ leak, contributing to myopathy and weakness. Circulating B-lymphocytes express RyR1 and catecholamine-responsive signaling cascades, making them a potential surrogate for defects in intracellular Ca2+ handling because of leaky RyR channels in CHF. METHODS Whole blood was collected from patients with CHF, CHF following left-ventricular assist device implant, and controls. Blood was also collected from mice with ischemic CHF, ischemic CHF+S107 (a drug that specifically reduces RyR channel Ca2+ leak), and wild-type controls. Channel macromolecular complex was assessed by immunostaining RyR1 immunoprecipitated from lymphocyte-enriched preparations. RyR1 Ca2+ leak was assessed using flow cytometry to measure Ca2+ fluorescence in B-lymphocytes in the absence and presence of RyR1 agonists that empty RyR1 Ca2+ stores within the endoplasmic reticulum. RESULTS Circulating B-lymphocytes from humans and mice with CHF exhibited remodeled RyR1 and decreased endoplasmic reticulum Ca2+ stores, consistent with chronic intracellular Ca2+ leak. This Ca2+ leak correlated with circulating catecholamine levels. The intracellular Ca2+ leak was significantly reduced in mice treated with the Rycal S107. Patients with CHF treated with left-ventricular assist devices exhibited a heterogeneous response. CONCLUSIONS In CHF, B-lymphocytes exhibit remodeled leaky RyR1 channels and decreased endoplasmic reticulum Ca2+ stores consistent with chronic intracellular Ca2+ leak. RyR1-mediated Ca2+ leak in B-lymphocytes assessed using flow cytometry provides a surrogate measure of intracellular Ca2+ handling and systemic sympathetic burden, presenting a novel biomarker for monitoring response to pharmacological and mechanical CHF therapy.
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Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York (A.K., G.S., S.R.R., A.R.M.).,Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Gaetano Santulli
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York (A.K., G.S., S.R.R., A.R.M.)
| | - Steven R Reiken
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York (A.K., G.S., S.R.R., A.R.M.)
| | - Ellie Coromilas
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Sarah J Godfrey
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Danielle L Brunjes
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Paolo C Colombo
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Melana Yuzefpolskaya
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Seth I Sokol
- Department of Medicine, Division of Cardiology, Jacobi Medical Center, Bronx, NY (S.I.S.)
| | - Richard N Kitsis
- Departments of Medicine and Cell Biology, Wilf Family Cardiovascular Research Institute, Albert Einstein Cancer Center, Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY (R.N.K.)
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York (A.K., G.S., S.R.R., A.R.M.).,Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
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Ottolini M, Hong K, Sonkusare SK. Calcium signals that determine vascular resistance. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2019; 11:e1448. [PMID: 30884210 PMCID: PMC6688910 DOI: 10.1002/wsbm.1448] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 02/07/2019] [Accepted: 02/14/2019] [Indexed: 12/19/2022]
Abstract
Small arteries in the body control vascular resistance, and therefore, blood pressure and blood flow. Endothelial and smooth muscle cells in the arterial walls respond to various stimuli by altering the vascular resistance on a moment to moment basis. Smooth muscle cells can directly influence arterial diameter by contracting or relaxing, whereas endothelial cells that line the inner walls of the arteries modulate the contractile state of surrounding smooth muscle cells. Cytosolic calcium is a key driver of endothelial and smooth muscle cell functions. Cytosolic calcium can be increased either by calcium release from intracellular stores through IP3 or ryanodine receptors, or the influx of extracellular calcium through ion channels at the cell membrane. Depending on the cell type, spatial localization, source of a calcium signal, and the calcium-sensitive target activated, a particular calcium signal can dilate or constrict the arteries. Calcium signals in the vasculature can be classified into several types based on their source, kinetics, and spatial and temporal properties. The calcium signaling mechanisms in smooth muscle and endothelial cells have been extensively studied in the native or freshly isolated cells, therefore, this review is limited to the discussions of studies in native or freshly isolated cells. This article is categorized under: Biological Mechanisms > Cell Signaling Laboratory Methods and Technologies > Imaging Models of Systems Properties and Processes > Mechanistic Models.
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Affiliation(s)
- Matteo Ottolini
- Robert M. Berne Cardiovascular Research Center, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
- Department of Pharmacology, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
| | - Kwangseok Hong
- Robert M. Berne Cardiovascular Research Center, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
- Department of Physical Education, Chung-Ang University, Seoul, 06974, South Korea
| | - Swapnil K. Sonkusare
- Robert M. Berne Cardiovascular Research Center, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
- Department of Pharmacology, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
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114
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Zhang M, Song R, Liu Y, Yi Z, Meng X, Zhang J, Tang Z, Yao Z, Liu Y, Liu X, Bu W. Calcium-Overload-Mediated Tumor Therapy by Calcium Peroxide Nanoparticles. Chem 2019. [DOI: 10.1016/j.chempr.2019.06.003] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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115
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Pierantozzi E, Szentesi P, Al-Gaadi D, Oláh T, Dienes B, Sztretye M, Rossi D, Sorrentino V, Csernoch L. Calcium Homeostasis Is Modified in Skeletal Muscle Fibers of Small Ankyrin1 Knockout Mice. Int J Mol Sci 2019; 20:ijms20133361. [PMID: 31323924 PMCID: PMC6651408 DOI: 10.3390/ijms20133361] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/01/2019] [Accepted: 07/04/2019] [Indexed: 11/16/2022] Open
Abstract
Small Ankyrins (sAnk1) are muscle-specific isoforms generated by the Ank1 gene that participate in the organization of the sarcoplasmic reticulum (SR) of striated muscles. Accordingly, the volume of SR tubules localized around the myofibrils is strongly reduced in skeletal muscle fibers of 4- and 10-month-old sAnk1 knockout (KO) mice, while additional structural alterations only develop with aging. To verify whether the lack of sAnk1 also alters intracellular Ca2+ handling, cytosolic Ca2+ levels were analyzed in stimulated skeletal muscle fibers from 4- and 10-month-old sAnk1 KO mice. The SR Ca2+ content was reduced in sAnk1 KO mice regardless of age. The amplitude of the Ca2+ transients induced by depolarizing pulses was decreased in myofibers of sAnk1 KO with respect to wild type (WT) fibers, while their voltage dependence was not affected. Furthermore, analysis of spontaneous Ca2+ release events (sparks) on saponin-permeabilized muscle fibers indicated that the frequency of sparks was significantly lower in fibers from 4-month-old KO mice compared to WT. Furthermore, both the amplitude and spatial spread of sparks were significantly smaller in muscle fibers from both 4- and 10-month-old KO mice compared to WT. These data suggest that the absence of sAnk1 results in an impairment of SR Ca2+ release, likely as a consequence of a decreased Ca2+ store due to the reduction of the SR volume in sAnk1 KO muscle fibers.
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Affiliation(s)
- Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, 53100 Siena, Italy
| | - Péter Szentesi
- Department of Physiology, Medical Faculty, University of Debrecen, H-4002 Debrecen, Hungary
| | - Dána Al-Gaadi
- Department of Physiology, Medical Faculty, University of Debrecen, H-4002 Debrecen, Hungary
- Doctoral School of Molecular Medicine, University of Debrecen, H-4002 Debrecen, Hungary
| | - Tamás Oláh
- Department of Physiology, Medical Faculty, University of Debrecen, H-4002 Debrecen, Hungary
| | - Beatrix Dienes
- Department of Physiology, Medical Faculty, University of Debrecen, H-4002 Debrecen, Hungary
| | - Mónika Sztretye
- Department of Physiology, Medical Faculty, University of Debrecen, H-4002 Debrecen, Hungary
| | - Daniela Rossi
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, 53100 Siena, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, 53100 Siena, Italy
| | - László Csernoch
- Department of Physiology, Medical Faculty, University of Debrecen, H-4002 Debrecen, Hungary.
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116
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Stochastic and deterministic approaches to modelling calcium release in cardiac myocytes at different spatial arrangements of ryanodine receptors. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2019; 48:579-584. [PMID: 31236612 DOI: 10.1007/s00249-019-01378-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/22/2019] [Accepted: 06/09/2019] [Indexed: 10/26/2022]
Abstract
Calcium release sites (CRSs) play a key role in excitation-contraction coupling of cardiac myocytes. Recent studies based on electron tomography and super-resolution imaging revealed that CRSs are not completely filled with ryanodine receptors (RyRs) and that the spatial arrangement of RyRs is neither uniform nor static. In this work, we studied the effect of spatial arrangement of RyRs on RyR activation using simulations based on Monte Carlo (MC) and mean-field (MF) approaches. Both approaches showed that activation of RyRs is sensitive to the arrangement of RyRs in the CRS. However, the MF simulations did not reproduce results of MC simulations for non-compact CRSs, suggesting that the approximations used in the MF approach are not suitable for simulation studies of RyRs arrangements observed experimentally. MC simulations revealed the importance of realistic spatial arrangement of RyRs for adequate modelling of calcium release in cardiac myocytes.
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117
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Mechanisms of Calcium Leak from Cardiac Sarcoplasmic Reticulum Revealed by Statistical Mechanics. Biophys J 2019; 116:2212-2223. [PMID: 31103231 DOI: 10.1016/j.bpj.2019.04.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 04/17/2019] [Accepted: 04/26/2019] [Indexed: 11/21/2022] Open
Abstract
Heart muscle contraction is normally activated by a synchronized Ca release from sarcoplasmic reticulum (SR), a major intracellular Ca store. However, under abnormal conditions, Ca leaks from the SR, decreasing heart contraction amplitude and increasing risk of life-threatening arrhythmia. The mechanisms and regimes of SR operation generating the abnormal Ca leak remain unclear. Here, we employed both numerical and analytical modeling to get mechanistic insights into the emergent Ca leak phenomenon. Our numerical simulations using a detailed realistic model of the Ca release unit reveal sharp transitions resulting in Ca leak. The emergence of leak is closely mapped mathematically to the Ising model from statistical mechanics. The system steady-state behavior is determined by two aggregate parameters: the analogs of magnetic field (h) and the inverse temperature (β) in the Ising model, for which we have explicit formulas in terms of SR [Ca] and release channel opening and closing rates. The classification of leak regimes takes the shape of a phase β-h diagram, with the regime boundaries occurring at h = 0 and a critical value of β (β∗) that we estimate using a classical Ising model and mean field theory. Our theory predicts that a synchronized Ca leak will occur when h > 0 and β >β∗, and a disordered leak occurs when β <β∗ and h is not too negative. The disorder leak is distinguished from synchronized leak (in long-lasting sparks) by larger Peierls contour lengths, an output parameter reflecting degree of disorder. Thus, in addition to our detailed numerical model approach, we also offer an instantaneous computational tool using analytical formulas of the Ising model for respective ryanodine receptor parameters and SR Ca load that describe and classify phase transitions and leak emergence.
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118
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Fernández-Miranda G, Romero-Garcia T, Barrera-Lechuga TP, Mercado-Morales M, Rueda A. Impaired Activity of Ryanodine Receptors Contributes to Calcium Mishandling in Cardiomyocytes of Metabolic Syndrome Rats. Front Physiol 2019; 10:520. [PMID: 31114513 PMCID: PMC6503767 DOI: 10.3389/fphys.2019.00520] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 04/11/2019] [Indexed: 01/11/2023] Open
Abstract
Metabolic syndrome (MetS) has become a global epidemic. MetS is a serious health problem because of its related cardiovascular complications, which include hypertension and delayed heart rate recovery after exercise. The molecular bases of cardiac dysfunction in MetS are still under scrutiny and may be related to anomalies in the activity and expression of key proteins involved in the cardiac excitation-contraction coupling (ECC). The cardiac Ca2+ channel/ryanodine receptor (RyR2) participates in releasing Ca2+ from internal stores and plays a key role in the modulation of ECC. We examined alterations in expression, phosphorylation status, Ca2+ sensitivity, and in situ function (by measuring Ca2+ sparks and Ca2+ transients) of RyR2; alterations in these characteristics could help to explain the Ca2+ handling disturbances in MetS cardiomyocytes. MetS was induced in rats by adding commercially refined sugar (30% sucrose) to their drinking water for 24 weeks. Cardiomyocytes of MetS rats displayed decreased Ca2+ transient amplitude and cell contractility at all stimulation frequencies. Quiescent MetS cardiomyocytes showed a decrease in Ca2+ spark frequency, amplitude, and spark-mediated Ca2+ leak. The [3H]-ryanodine binding data showed that functionally active RyRs are significantly diminished in MetS heart microsomes; and exhibited rapid Ca2+-induced inactivation. The phosphorylation of corresponding Ser2814 (a preferential target for CaMKII) of the hRyR2 was significantly diminished. RyR2 protein expression and Ser2808 phosphorylation level were both unchanged. Further, we demonstrated that cardiomyocyte Ca2+ mishandling was associated with reduced SERCA pump activity due to decreased Thr17-PLN phosphorylation, suggesting a downregulation of CaMKII in MetS hearts, though the SR Ca2+ load remained unchanged. The reduction in the phosphorylation level of RyR2 at Ser2814 decreases RyR2 availability for activation during ECC. In conclusion, the impaired in situ activity of RyR2 may also account for the poor overall cardiac outcome reported in MetS patients; hence, the SERCA pump and RyR2 are both attractive potential targets for future therapies.
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Affiliation(s)
- Gaudencio Fernández-Miranda
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
| | - Tatiana Romero-Garcia
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
| | - Tarín P Barrera-Lechuga
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
| | - Martha Mercado-Morales
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
| | - Angélica Rueda
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Mexico City, Mexico
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119
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Gupta S, Manchanda R. A computational model of large conductance voltage and calcium activated potassium channels: implications for calcium dynamics and electrophysiology in detrusor smooth muscle cells. J Comput Neurosci 2019; 46:233-256. [PMID: 31025235 DOI: 10.1007/s10827-019-00713-9] [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: 09/11/2018] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 11/25/2022]
Abstract
The large conductance voltage and calcium activated potassium (BK) channels play a crucial role in regulating the excitability of detrusor smooth muscle, which lines the wall of the urinary bladder. These channels have been widely characterized in terms of their molecular structure, pharmacology and electrophysiology. They control the repolarising and hyperpolarising phases of the action potential, thereby regulating the firing frequency and contraction profiles of the smooth muscle. Several groups have reported varied profiles of BK currents and I-V curves under similar experimental conditions. However, no single computational model has been able to reconcile these apparent discrepancies. In view of the channels' physiological importance, it is imperative to understand their mechanistic underpinnings so that a realistic model can be created. This paper presents a computational model of the BK channel, based on the Hodgkin-Huxley formalism, constructed by utilising three activation processes - membrane potential, calcium inflow from voltage-gated calcium channels on the membrane and calcium released from the ryanodine receptors present on the sarcoplasmic reticulum. In our model, we attribute the discrepant profiles to the underlying cytosolic calcium received by the channel during its activation. The model enables us to make heuristic predictions regarding the nature of the sub-membrane calcium dynamics underlying the BK channel's activation. We have employed the model to reproduce various physiological characteristics of the channel and found the simulated responses to be in accordance with the experimental findings. Additionally, we have used the model to investigate the role of this channel in electrophysiological signals, such as the action potential and spontaneous transient hyperpolarisations. Furthermore, the clinical effects of BK channel openers, mallotoxin and NS19504, were simulated for the detrusor smooth muscle cells. Our findings support the proposed application of these drugs for amelioration of the condition of overactive bladder. We thus propose a physiologically realistic BK channel model which can be integrated with other biophysical mechanisms such as ion channels, pumps and exchangers to further elucidate its micro-domain interaction with the intracellular calcium environment.
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Affiliation(s)
- Suranjana Gupta
- Computational NeuroPhysiology Lab, Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Rohit Manchanda
- Computational NeuroPhysiology Lab, Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India.
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120
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Yang Z, Yan H, Dai W, Jing J, Yang Y, Mahajan S, Zhou Y, Li W, Macaubas C, Mellins ED, Shih CC, Fitzpatrick JAJ, Faccio R. Tmem178 negatively regulates store-operated calcium entry in myeloid cells via association with STIM1. J Autoimmun 2019; 101:94-108. [PMID: 31018906 DOI: 10.1016/j.jaut.2019.04.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/09/2019] [Accepted: 04/12/2019] [Indexed: 12/27/2022]
Abstract
Store-operated calcium entry (SOCE) modulates cytosolic calcium in multiple cells. Endoplasmic reticulum (ER)-localized STIM1 and plasma membrane (PM)-localized ORAI1 are two main components of SOCE. STIM1:ORAI1 association requires STIM1 oligomerization, its re-distribution to ER-PM junctions, and puncta formation. However, little is known about the negative regulation of these steps to prevent calcium overload. Here, we identified Tmem178 as a negative modulator of STIM1 puncta formation in myeloid cells. Using site-directed mutagenesis, co-immunoprecipitation assays and FRET imaging, we determined that Tmem178:STIM1 association occurs via their transmembrane motifs. Mutants that increase Tmem178:STIM1 association reduce STIM1 puncta formation, SOCE activation, impair inflammatory cytokine production in macrophages and osteoclastogenesis. Mutants that reduce Tmem178:STIM1 association reverse these effects. Furthermore, exposure to plasma from arthritic patients decreases Tmem178 expression, enhances SOCE activation and cytoplasmic calcium. In conclusion, Tmem178 modulates the rate-limiting step of STIM1 puncta formation and therefore controls SOCE in inflammatory conditions.
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Affiliation(s)
- Zhengfeng Yang
- Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Hui Yan
- Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Wentao Dai
- Shanghai Center for Bioinformation Technology & Shanghai Engineering Research Center of Pharmaceutical Translation, Shanghai Industrial Technology Institute, 1278 Keyuan Road, Shanghai, 201203, China
| | - Ji Jing
- Institute of Biosciences and Technology, Texas A&M University College of Medicine, Houston, TX 77030, USA
| | - Yihu Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Sahil Mahajan
- Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Yubin Zhou
- Institute of Biosciences and Technology, Texas A&M University College of Medicine, Houston, TX 77030, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Claudia Macaubas
- Department of Pediatrics, Program in Immunology, Stanford University, Stanford, CA 94305, USA
| | - Elizabeth D Mellins
- Department of Pediatrics, Program in Immunology, Stanford University, Stanford, CA 94305, USA
| | - Chien-Cheng Shih
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - James A J Fitzpatrick
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St. Louis, MO, 63110, USA; Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, MO, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - Roberta Faccio
- Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, 63110, USA; Shriners Hospitals for Children, St. Louis MO, USA.
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121
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Laasmaa M, Karro N, Birkedal R, Vendelin M. IOCBIO Sparks detection and analysis software. PeerJ 2019; 7:e6652. [PMID: 30956900 PMCID: PMC6442673 DOI: 10.7717/peerj.6652] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 02/19/2019] [Indexed: 12/01/2022] Open
Abstract
Analysis of calcium sparks in cardiomyocytes can provide valuable information about functional changes of calcium handling in health and disease. As a part of the calcium sparks analysis, sparks detection and characterization is necessary. Here, we describe a new open-source platform for automatic calcium sparks detection from line scan confocal images. The developed software is tailored for detecting only calcium sparks, allowing us to design a graphical user interface specifically for this task. The software enables detecting sparks automatically as well as adding, removing, or adjusting regions of interest marking each spark. The results of the analysis are stored in an SQL database, allowing simple integration with statistical tools. We have analyzed the performance of the algorithm using a large set of synthetic images with varying spark sizes and noise levels and also compared the analysis results with results obtained by software established in the field. The use of our software is illustrated by an analysis of the effect of isoprenaline (ISO) on spark frequency, amplitude, and spatial and temporal characteristics. For that, cardiomyocytes from C57BL/6 mice were used. We demonstrated an increase in spark frequency, tendency of having larger spark amplitudes, sparks with a longer duration, and occurrence of multiple sparks from the same site in the presence of ISO. We also show that the duration and the width of sparks with the same amplitude were similar in the absence and presence of ISO. The software was released as an open source repository and is available for free use and collaborative development.
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Affiliation(s)
- Martin Laasmaa
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Niina Karro
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Rikke Birkedal
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Marko Vendelin
- Laboratory of Systems Biology, Department of Cybernetics, School of Science, Tallinn University of Technology, Tallinn, Estonia
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Lu F, Sun J, Zheng Q, Li J, Hu Y, Yu P, He H, Zhao Y, Wang X, Yang S, Cheng H. Imaging elemental events of store-operated Ca 2+ entry in invading cancer cells with plasmalemmal targeted sensors. J Cell Sci 2019; 132:jcs.224923. [PMID: 30814332 DOI: 10.1242/jcs.224923] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 02/04/2019] [Indexed: 12/14/2022] Open
Abstract
STIM1- and Orai1-mediated store-operated Ca2+ entry (SOCE) constitutes the major Ca2+ influx in almost all electrically non-excitable cells. However, little is known about the spatiotemporal organization at the elementary level. Here, we developed Orai1-tethered or palmitoylated biosensor GCaMP6f to report subplasmalemmal Ca2+ signals. We visualized spontaneous discrete and long-lasting transients ('Ca2+ glows') arising from STIM1-Orai1 in invading melanoma cells. Ca2+ glows occurred preferentially in single invadopodia and at sites near the cell periphery under resting conditions. Re-addition of external Ca2+ after store depletion elicited spatially synchronous Ca2+ glows, followed by high-rate discharge of asynchronous local events. Knockout of STIM1 or expression of the dominant-negative Orai1-E106A mutant markedly decreased Ca2+ glow frequency, diminished global SOCE and attenuated invadopodial formation. Functionally, invadopodial Ca2+ glows provided high Ca2+ microdomains to locally activate Ca2+/calmodulin-dependent Pyk2 (also known as PTK2B), which initiates the SOCE-Pyk2-Src signaling cascade required for invasion. Overall, the discovery of elemental Ca2+ signals of SOCE not only unveils a previously unappreciated gating mode of STIM1-Orai1 channels in situ, but also underscores a critical role of the spatiotemporal dynamics of SOCE in orchestrating complex cell behaviors such as invasion. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Fujian Lu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jianwei Sun
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA 17033, USA.,State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Qiaoxia Zheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jinghang Li
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yuanzhao Hu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Peng Yu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Huifang He
- Department of Tumor Biology, H. Lee Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Yan Zhao
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Xianhua Wang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Shengyu Yang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, PA 17033, USA .,Department of Tumor Biology, H. Lee Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
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123
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Abstract
Fundamental cell processes such as synaptic neurotransmitter release, endocrine hormone secretion, and myocyte contraction are controlled by highly localized calcium (Ca2+) signals resulting from brief openings of trans-membrane Ca2+ channels. On short temporal and spatial scales, the corresponding local Ca2+ nanodomains formed in the vicinity of a single or several open Ca2+ channels can be effectively approximated by quasi-stationary solutions. The rapid buffering approximation (RBA) is one of the most powerful of such approximations, and is based on the assumption of instantaneous equilibration of the bimolecular Ca2+ buffering reaction, combined with the conservation condition for the total Ca2+ and buffer molecule numbers. Previously, RBA has been generalized to an arbitrary arrangement of Ca2+ channels on a flat membrane, in the presence of any number of simple Ca2+ buffers with one-to-one Ca2+ binding stoichiometry. However, many biological buffers have multiple binding sites. For example, buffers and sensors phylogenetically related to calmodulin consist of two Ca2+-binding domains (lobes), with each domain binding two Ca2+ ions in a cooperative manner. Here we consider an extension of RBA to such buffers with two interdependent Ca2+ binding sites. We show that in the presence of such buffers, RBA solution is given by the solution to a cubic equation, analogous to the quadratic equation describing RBA in the case of a simple, one-to-one Ca2+ buffer. We examine in detail the dependence of RBA accuracy on buffering parameters, to reveal conditions under which RBA provides sufficient precision.
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Affiliation(s)
- Victor Matveev
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey.
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124
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Hiess F, Detampel P, Nolla-Colomer C, Vallmitjana A, Ganguly A, Amrein M, Ter Keurs HEDJ, Benítez R, Hove-Madsen L, Chen SRW. Dynamic and Irregular Distribution of RyR2 Clusters in the Periphery of Live Ventricular Myocytes. Biophys J 2019; 114:343-354. [PMID: 29401432 DOI: 10.1016/j.bpj.2017.11.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/01/2017] [Accepted: 11/03/2017] [Indexed: 10/18/2022] Open
Abstract
Cardiac ryanodine receptors (RyR2s) are Ca2+ release channels clustering in the sarcoplasmic reticulum membrane. These clusters are believed to be the elementary units of Ca2+ release. The distribution of these Ca2+ release units plays a critical role in determining the spatio-temporal profile and stability of sarcoplasmic reticulum Ca2+ release. RyR2 clusters located in the interior of cardiomyocytes are arranged in highly ordered arrays. However, little is known about the distribution and function of RyR2 clusters in the periphery of cardiomyocytes. Here, we used a knock-in mouse model expressing a green fluorescence protein (GFP)-tagged RyR2 to localize RyR2 clusters in live ventricular myocytes by virtue of their GFP fluorescence. Confocal imaging and total internal reflection fluorescence microscopy was employed to determine and compare the distribution of GFP-RyR2 in the interior and periphery of isolated live ventricular myocytes and in intact hearts. We found tightly ordered arrays of GFP-RyR2 clusters in the interior, as previously described. In contrast, irregular distribution of GFP-RyR2 clusters was observed in the periphery. Time-lapse total internal reflection fluorescence imaging revealed dynamic movements of GFP-RyR2 clusters in the periphery, which were affected by external Ca2+ and RyR2 activator (caffeine) and inhibitor (tetracaine), but little detectable movement of GFP-RyR2 clusters in the interior. Furthermore, simultaneous Ca2+- and GFP-imaging demonstrated that peripheral RyR2 clusters with an irregular distribution pattern are functional with a Ca2+ release profile similar to that in the interior. These results indicate that the distribution of RyR2 clusters in the periphery of live ventricular myocytes is irregular and dynamic, which is different from that of RyR2 clusters in the interior.
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Affiliation(s)
- Florian Hiess
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Pascal Detampel
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Carme Nolla-Colomer
- Automatic Control Department, Universitat Politècnica de Catalunya-Barcelona Tech, Barcelona, Spain
| | - Alex Vallmitjana
- Automatic Control Department, Universitat Politècnica de Catalunya-Barcelona Tech, Barcelona, Spain
| | - Anutosh Ganguly
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Matthias Amrein
- Department of Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada
| | - Henk E D J Ter Keurs
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Raul Benítez
- Automatic Control Department, Universitat Politècnica de Catalunya-Barcelona Tech, Barcelona, Spain
| | - Leif Hove-Madsen
- Biomedical Research Institute Barcelona CSIC-IIBB, Sant Pau, Hospital de Sant Pau, Barcelona, Spain
| | - S R Wayne Chen
- Libin Cardiovascular Institute of Alberta, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.
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125
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Romero L, Alvarez-Lacalle E, Shiferaw Y. Stochastic coupled map model of subcellular calcium cycling in cardiac cells. CHAOS (WOODBURY, N.Y.) 2019; 29:023125. [PMID: 30823735 PMCID: PMC7043839 DOI: 10.1063/1.5063462] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
In this study, we analyze a nonlinear map model of intracellular calcium (Ca) and voltage in cardiac cells. In this model, Ca release from the sarcoplasmic reticulum (SR) occurs at spatially distributed dyadic junctions that are diffusively coupled. At these junctions, release occurs with a probability that depends on key variables such as the SR load and the diastolic interval. Using this model, we explore how nonlinearity and stochasticity determine the spatial distribution of Ca release events within a cardiac cell. In particular, we identify a novel synchronization transition, which occurs at rapid pacing rates, in which the global Ca transient transitions from a period 2 response to a period 1 response. In the global period 2 response dyadic junctions fire in unison, on average, on alternate beats, while in the period 1 regime, Ca release at individual dyads is highly irregular. A close examination of the spatial distribution of Ca reveals that in the period 1 regime, the system coarsens into spatially out-of-phase regions with a length scale much smaller than the system size, but larger than the spacing between dyads. We have also explored in detail the coupling to membrane voltage. We study first the case of positive coupling, where a large Ca transient promotes a long action potential duration (APD). Here, the coupling to voltage synchronizes Ca release so that the system exhibits a robust period 2 response that is independent of initial conditions. On the other hand, in the case of negative coupling, where a large Ca transient tends to shorten the APD, we find a multitude of metastable states which consist of complex spatially discordant alternans patterns. Using an analogy to equilibrium statistical mechanics, we show that the spatial patterns observed can be explained by a mapping to the Potts model, with an additional term that accounts for a global coupling of spin states. Using this analogy, we argue that Ca cycling in cardiac cells exhibits complex spatiotemporal patterns that emerge via first or second order phase transitions. These results show that voltage and Ca can interact in order to induce complex subcellular responses, which can potentially lead to heart rhythm disorders.
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Affiliation(s)
- Luis Romero
- Department of Physics, California State University, Northridge, California 91330, USA
| | - Enric Alvarez-Lacalle
- Departament de Fisica, Universitat Politècnica de Catalunya, BarcelonaTech, 08028 Barcelona, Spain
| | - Yohannes Shiferaw
- Department of Physics, California State University, Northridge, California 91330, USA
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126
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Krzesiak A, Cognard C, Sebille S, Carré G, Bosquet L, Delpech N. High-intensity intermittent training is as effective as moderate continuous training, and not deleterious, in cardiomyocyte remodeling of hypertensive rats. J Appl Physiol (1985) 2019; 126:903-915. [PMID: 30702976 DOI: 10.1152/japplphysiol.00131.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Exercise training offers possible nonpharmacological therapy for cardiovascular diseases including hypertension. High-intensity intermittent exercise (HIIE) training has been shown to have as much or even more beneficial cardiovascular effect in patients with cardiovascular diseases than moderate-intensity continuous exercise (CMIE) training. The aim of this study was to investigate the effects of the two types of training on cardiac remodeling of spontaneously hypertensive rats (SHR) induced by hypertension. Eight-week-old male SHR and normotensive Wistar-Kyoto rats (WKY) were divided into four groups: normotensive and hypertensive control (WKY and SHR-C) and hypertensive trained with CMIE (SHR-T CMIE) or HIIE (SHR-T HIIE). After 8 wk of training or inactivity, maximal running speed (MRS), arterial pressure, and heart weight were all assessed. CMIE or HIIE protocols not only increased final MRS and left ventricular weight/body weight ratio but also reduced mean arterial pressure compared with sedentary group. Then, left ventricular tissue was enzymatically dissociated, and isolated cardiomyocytes were used to highlight the changes induced by physical activity at morphological, mechanical, and molecular levels. Both types of training induced restoration of transverse tubule regularity, decrease in spark site density, and reduction in half-relaxation time of calcium transients. HIIE training, in particular, decreased spark amplitude and width, and increased cardiomyocyte contractility and the expression of sarco(endo)plasmic reticulum Ca2+-ATPase and phospholamban phosphorylated on serine 16. NEW & NOTEWORTHY High-intensity intermittent exercise training induces beneficial remodeling of the left ventricular cardiomyocytes of spontaneously hypertensive rats at the morphological, mechanical, and molecular levels. Results also confirm, at the cellular level, that this type of training, as it appears not to be deleterious, could be applied in rehabilitation of hypertensive patients.
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Affiliation(s)
- A Krzesiak
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France.,Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
| | - C Cognard
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - S Sebille
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - G Carré
- Equipe Transferts Ioniques et Rythmicité Cellulaire, Laboratory Signalisation et Transports Ioniques Membranaires, Université de Poitiers, EA 7349, Faculté des Sciences Fondamentales et Appliquées , Poitiers , France
| | - L Bosquet
- Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
| | - N Delpech
- Laboratoire Mobilité, Vieillissement, and Exercice, EA 6314, Université de Poitiers, Faculté des Sciences du Sport , Poitiers , France
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127
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Joca HC, Coleman AK, Ward CW, Williams GSB. Quantitative tests reveal that microtubules tune the healthy heart but underlie arrhythmias in pathology. J Physiol 2019; 598:1327-1338. [PMID: 30582750 PMCID: PMC7432954 DOI: 10.1113/jp277083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 12/14/2018] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS Our group previously discovered and characterized the microtubule mechanotransduction pathway linking diastolic stretch to NADPH oxidase 2-derived reactive oxygen species signals that regulate calcium sparks and calcium influx pathways. Here we used focused experimental tests to constrain and expand our existing computational models of calcium signalling in heart. Mechanistic and quantitative modelling revealed new insights in disease including: changes in microtubule network density and properties, elevated NOX2 expression, altered calcium release dynamics, how NADPH oxidase 2 is activated by and responds to stretch, and finally the degree to which normalizing mechano-activated reactive oxygen species signals can prevent calcium-dependent arrhythmias. ABSTRACT Microtubule (MT) mechanotransduction links diastolic stretch to generation of NADPH oxidase 2 (NOX2)-dependent reactive oxygen species (ROS), signals we term X-ROS. While stretch-elicited X-ROS primes intracellular calcium (Ca2+ ) channels for synchronized activation in the healthy heart, the dysregulated excess in this pathway underscores asynchronous Ca2+ release and arrhythmia. Here, we expanded our existing computational models of Ca2+ signalling in heart to include MT-dependent mechanotransduction through X-ROS. Informed by new focused experimental tests to properly constrain our model, we quantify the role of X-ROS on excitation-contraction coupling in healthy and pathological conditions. This approach allowed for a mechanistic investigation that revealed new insights into X-ROS signalling in disease including changes in MT network density and post-translational modifications (PTMs), elevated NOX2 expression, altered Ca2+ release dynamics (i.e. Ca2+ sparks and Ca2+ waves), how NOX2 is activated by and responds to stretch, and finally the degree to which normalizing X-ROS can prevent Ca2+ -dependent arrhythmias.
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Affiliation(s)
- Humberto C Joca
- Centre for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrew K Coleman
- Centre for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Chris W Ward
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - George S B Williams
- Centre for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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128
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Feng R, Zhou X, Zhang W, Pu T, Sun Y, Yang R, Wang D, Zhang X, Gao Y, Cai Z, Liang Y, Yu Q, Wu Y, Lei X, Liang Z, Jones O, Wang L, Xu M, Sun Y, Isaacs WB, Ma J, Xu X. Dynamics expression of DmFKBP12/Calstabin during embryonic early development of Drosophila melanogaster. Cell Biosci 2019; 9:8. [PMID: 30637096 PMCID: PMC6325743 DOI: 10.1186/s13578-019-0270-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/02/2019] [Indexed: 12/19/2022] Open
Abstract
Background Calcium signaling are conserved from invertebrates to vertebrates and plays critical roles in many molecular mechanisms of embryogenesis and postnatal development. As a critical component of the signaling pathway, the RyR medicated calcium-induced calcium release signaling system, has been well studied along with their regulator FK506-binding protein 12 (FKBP12/Calstabin). Lack of FKBP12 is known to result in lethal cardiac dysfunction in mouse. However, precisely how FKBP12 is regulated and effects calcium signaling in Drosophila melanogaster remains largely unknown. Results In this study, we identified both temporal and localization changes in expression of DmFKBP12, a translational and transcriptional regulator of Drosophila RyR (DmRyR) and FKBP12, through embryonic development. DmFKBP12 is first expressed at the syncytial blastoderm stage and undergoes increased expression during the cellular blastoderm and early gastrulation stages. At late gastrulation, DmFKBP12 expression begins to decline until it reaches homeostasis, which it then maintains throughout the rest of development. Throughout these described changes in expression, DmFKBP12 mRNA remain stable, which indicates that protein dynamics are attributed to regulation at the mRNA to protein translation level. In addition to temporal changes in expression, dynamic expression profiles during Drosophila development also revealed DmFKBP12 localization. Although DmFKBP12 is distributed evenly between the anterior to posterior poles of the blastoderm egg, the protein is expressed more strongly in the cortex of the early Drosophila gastrula with the highest concentration found in the basement membrane of the cellular blastoderm. Fertilized egg, through the profile as under-membrane cortex distribution concentering onto basement at cellular blastoderm, to the profile as three-gem layer localization in primitive neuronal and digestion architecture of early Drosophila gastrula. By late gastrulation, DmFKBP12 is no longer identified in the yolk or lumen of duct structures and has relocated to the future brain (suboesophageal and supraesophageal ganglions), ventral nervous system, and muscular system. Throughout these changes in distribution, in situ DmFKBP12 mRNA monitoring detected equal distribution of DmFKBP12 mRNA, once again indicating that regulation of DmFKBP12 occurs at the translational level in Drosophila development. Conclusion As a critical regulator of the DmRyR-FKBP complex, DmFKBP12 expression in Drosophila fluctuates temporally and geographically with the formation of organ systems. These finding indicate that DmFKBP12 and RyR associated calcium signaling plays an essential role in the successful development of Drosophila melanogaster. Further study on the differences between mammalian RyR-FKBP12 and Drosophila DmRyR-FKBP12 can be exploited to develop safe pesticides. Electronic supplementary material The online version of this article (10.1186/s13578-019-0270-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rui Feng
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Xin Zhou
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China.,2Ohio State University School of Medicine, Columbus, OH 43210 USA
| | - Wei Zhang
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Tao Pu
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Yuting Sun
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Rong Yang
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Dan Wang
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Xiaofei Zhang
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Yingfeng Gao
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Zhenlu Cai
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Yu Liang
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Qiuxia Yu
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Yajun Wu
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Xinjuan Lei
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Zhijia Liang
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
| | - Odell Jones
- 4University of Pennsylvania ULAR, Philadelphia, PA 19144 USA
| | - Liyang Wang
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China.,Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215 USA
| | - Mengmeng Xu
- 5Medical-Scientist Training Program, Department of Pharmacology, Duke University Medical Center, Durham, NC 27710 USA
| | - Yanping Sun
- 6College of Pharmacy, Xi'an Medical University, Xi'an, 710062 China
| | | | - Jianjie Ma
- 2Ohio State University School of Medicine, Columbus, OH 43210 USA
| | - Xuehong Xu
- 1National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China/CGDB, Shaanxi Normal University College of Life Sciences, Xi'an, 710062 China
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129
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Arif S, Lai CH, Ramesh NI. Estimation of stochastic behaviour in cardiac myocytes: I. Ca 2+ movements inside the cytosol and sarcoplasmic reticulum on curvilinear domains. JRSM Cardiovasc Dis 2019; 8:2048004018822428. [PMID: 30643637 PMCID: PMC6322098 DOI: 10.1177/2048004018822428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 07/06/2018] [Accepted: 11/13/2018] [Indexed: 11/15/2022] Open
Abstract
Since the discovery of Ca2+ sparks and their stochastic behaviour in cardiac myocytes, models have focused on the inclusion of stochasticity in their studies. While most models pay much attention to the stochastic modelling of cytosolic Ca2+ concentration the coupling of Ca2+ sparks and blinks in a stochastic model has not been explored fully. The cell morphology in in silico studies in the past is assumed to be Cartesian, spherical or cylindrical. The application on curvilinear grids can easily address certain restrictions posed by such grid set up and provide more realistic cell morphology. In this paper, we present a stochastic reaction-diffusion model that couples Ca2+ sparks and blinks in realistic shapes of cells in curvilinear domains. Methodology: Transformation of the model was performed to the curvilinear coordinate system. The set of equations is used to produce Ca2+ waves initiated from sparks and blinks. A non-buffered and non-dyed version as well as a buffered and dyed version of these equations were studied in light of observing the dynamics on the two different systems. For comparison, results for both the Cartesian and curvilinear grids are provided. Results and conclusions: A successful demonstration of the application of curvilinear grids serving as basis for future developments.
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Affiliation(s)
- Serife Arif
- Department of Mathematical Sciences, Faculty of Architecture, Computing and Humanities University of Greenwich, London, UK
| | - Choi-Hong Lai
- Department of Mathematical Sciences, Faculty of Architecture, Computing and Humanities University of Greenwich, London, UK
| | - Nadarajah I Ramesh
- Department of Mathematical Sciences, Faculty of Architecture, Computing and Humanities University of Greenwich, London, UK
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130
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Rouhana S, Farah C, Roy J, Finan A, Rodrigues de Araujo G, Bideaux P, Scheuermann V, Saliba Y, Reboul C, Cazorla O, Aimond F, Richard S, Thireau J, Fares N. Early calcium handling imbalance in pressure overload-induced heart failure with nearly normal left ventricular ejection fraction. Biochim Biophys Acta Mol Basis Dis 2019; 1865:230-242. [DOI: 10.1016/j.bbadis.2018.08.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 07/13/2018] [Accepted: 08/02/2018] [Indexed: 02/07/2023]
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131
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Rossi AM, Taylor CW. IP3 receptors – lessons from analyses ex cellula. J Cell Sci 2018; 132:132/4/jcs222463. [DOI: 10.1242/jcs.222463] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
ABSTRACT
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are widely expressed intracellular channels that release Ca2+ from the endoplasmic reticulum (ER). We review how studies of IP3Rs removed from their intracellular environment (‘ex cellula’), alongside similar analyses of ryanodine receptors, have contributed to understanding IP3R behaviour. Analyses of permeabilized cells have demonstrated that the ER is the major intracellular Ca2+ store, and that IP3 stimulates Ca2+ release from this store. Radioligand binding confirmed that the 4,5-phosphates of IP3 are essential for activating IP3Rs, and facilitated IP3R purification and cloning, which paved the way for structural analyses. Reconstitution of IP3Rs into lipid bilayers and patch-clamp recording from the nuclear envelope have established that IP3Rs have a large conductance and select weakly between Ca2+ and other cations. Structural analyses are now revealing how IP3 binding to the N-terminus of the tetrameric IP3R opens the pore ∼7 nm away from the IP3-binding core (IBC). Communication between the IBC and pore passes through a nexus of interleaved domains contributed by structures associated with the pore and cytosolic domains, which together contribute to a Ca2+-binding site. These structural analyses provide evidence to support the suggestion that IP3 gates IP3Rs by first stimulating Ca2+ binding, which leads to pore opening and Ca2+ release.
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Affiliation(s)
- Ana M. Rossi
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Colin W. Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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132
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Mhatre KN, Wakula P, Klein O, Bisping E, Völkl J, Pieske B, Heinzel FR. Crosstalk between FGF23- and angiotensin II-mediated Ca 2+ signaling in pathological cardiac hypertrophy. Cell Mol Life Sci 2018; 75:4403-4416. [PMID: 30062428 PMCID: PMC11105615 DOI: 10.1007/s00018-018-2885-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 02/07/2023]
Abstract
Heart failure (HF) manifestation and progression are driven by systemic activation of neuroendocrine signaling cascades, such as the renin-angiotensin aldosterone system (RAAS). Fibroblast growth factor 23 (FGF23), an endocrine hormone, is linked to HF and cardiovascular mortality. It is also a mediator of left-ventricular hypertrophy (LVH). In vivo, high circulating levels of FGF23 are associated with an altered systemic RAAS response. FGF23 is proposed to trigger pathological signaling mediated by Ca2+-regulated transcriptional pathways. In the present study, we investigated Ca2+-dependent signaling of FGF23 in ventricular cardiomyocytes and its association with angiotensin II (ATII). In neonatal rat ventricular myocytes (NRVMs), both ATII and FGF23 induced hypertrophy as observed by an increase in cell area and hypertrophic gene expression. Furthermore, FGF23 activates nuclear Ca2+-regulated CaMKII-HDAC4 pathway, similar to ATII. In addition to a global increase in cytoplasmic Ca2+, FGF23, like ATII, induced inositol 1, 4, 5-triphosphate (IP3)-induced Ca2+ release from the nucleoplasmic Ca2+ store, associated with cellular hypertrophy. Interestingly, ATII receptor antagonist, losartan, significantly attenuated FGF23-induced changes in Ca2+ homeostasis and cellular hypertrophy suggesting an involvement of ATII receptor-mediated signaling. In addition, application of FGF23 increased intracellular expression of ATII peptide and its secretion in NRVMs, confirming the participation of ATII. In conclusion, FGF23 and ATII share a common mechanism of IP3-nuclear Ca2+-dependent cardiomyocyte hypertrophy. FGF23-mediated cellular hypertrophy is associated with increased production and secretion of ATII by cardiomyocytes. These findings indicate a pathophysiological role of the cellular angiotensin system in FGF23-induced hypertrophy in ventricular cardiomyocytes.
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Affiliation(s)
- Ketaki N Mhatre
- Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, 13353, Berlin, Germany
- Department of Cardiology, Medical University Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Paulina Wakula
- Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, 13353, Berlin, Germany
| | - Oliver Klein
- Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, 13353, Berlin, Germany
| | - Egbert Bisping
- Department of Cardiology, Medical University Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Jakob Völkl
- Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, 13353, Berlin, Germany
| | - Burkert Pieske
- Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, 13353, Berlin, Germany
- German Center for Cardiovascular Research (DZHK), Berlin, Germany
- Department of Internal Medicine and Cardiology, German Heart Center, 13353, Berlin, Germany
| | - Frank R Heinzel
- Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, 13353, Berlin, Germany.
- German Center for Cardiovascular Research (DZHK), Berlin, Germany.
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133
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Applications of FLIKA, a Python-based image processing and analysis platform, for studying local events of cellular calcium signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:1171-1179. [PMID: 30500432 DOI: 10.1016/j.bbamcr.2018.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/20/2018] [Accepted: 11/22/2018] [Indexed: 11/21/2022]
Abstract
The patterning of cytosolic Ca2+ signals underlies their ubiquitous ability to specifically regulate numerous cellular processes. Advances in fluorescence microscopy have made it possible to image these signals with unprecedented temporal and spatial resolution. However, this is a double-edged sword, as the resulting enormous data sets necessitate development of software to automate image processing and analysis. Here, we describe Flika, an open source, graphical user interface program written in the Python environment that contains a suite of built-in image processing tools to enable intuitive visualization of image data and analysis. We illustrate the utility and power of Flika by three applications for studying cellular Ca2+ signaling: a script for measuring single-cell global Ca2+ signals; a plugin for the detection, localization and analysis of subcellular Ca2+ puffs; and a script that implements a novel approach for fluctuation analysis of transient, local Ca2+ fluorescence signals. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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134
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SICT: automated detection and supervised inspection of fast Ca 2+ transients. Sci Rep 2018; 8:15523. [PMID: 30341397 PMCID: PMC6195629 DOI: 10.1038/s41598-018-33847-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/05/2018] [Indexed: 02/06/2023] Open
Abstract
Recent advances in live Ca2+ imaging with increasing spatial and temporal resolution offer unprecedented opportunities, but also generate an unmet need for data processing. Here we developed SICT, a MATLAB program that automatically identifies rapid Ca2+ rises in time-lapse movies with low signal-to-noise ratios, using fluorescent indicators. A graphical user interface allows visual inspection of automatically detected events, reducing manual labour to less than 10% while maintaining quality control. The detection performance was tested using synthetic data with various signal-to-noise ratios. The event inspection phase was evaluated by four human observers. Reliability of the method was demonstrated in a direct comparison between manual and SICT-aided analysis. As a test case in cultured neurons, SICT detected an increase in frequency and duration of spontaneous Ca2+ transients in the presence of caffeine. This new method speeds up the analysis of elementary Ca2+ transients.
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135
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Johnson DM, Antoons G. Arrhythmogenic Mechanisms in Heart Failure: Linking β-Adrenergic Stimulation, Stretch, and Calcium. Front Physiol 2018; 9:1453. [PMID: 30374311 PMCID: PMC6196916 DOI: 10.3389/fphys.2018.01453] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/25/2018] [Indexed: 12/22/2022] Open
Abstract
Heart failure (HF) is associated with elevated sympathetic tone and mechanical load. Both systems activate signaling transduction pathways that increase cardiac output, but eventually become part of the disease process itself leading to further worsening of cardiac function. These alterations can adversely contribute to electrical instability, at least in part due to the modulation of Ca2+ handling at the level of the single cardiac myocyte. The major aim of this review is to provide a definitive overview of the links and cross talk between β-adrenergic stimulation, mechanical load, and arrhythmogenesis in the setting of HF. We will initially review the role of Ca2+ in the induction of both early and delayed afterdepolarizations, the role that β-adrenergic stimulation plays in the initiation of these and how the propensity for these may be altered in HF. We will then go onto reviewing the current data with regards to the link between mechanical load and afterdepolarizations, the associated mechano-sensitivity of the ryanodine receptor and other stretch activated channels that may be associated with HF-associated arrhythmias. Furthermore, we will discuss how alterations in local Ca2+ microdomains during the remodeling process associated the HF may contribute to the increased disposition for β-adrenergic or stretch induced arrhythmogenic triggers. Finally, the potential mechanisms linking β-adrenergic stimulation and mechanical stretch will be clarified, with the aim of finding common modalities of arrhythmogenesis that could be targeted by novel therapeutic agents in the setting of HF.
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Affiliation(s)
- Daniel M Johnson
- Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
| | - Gudrun Antoons
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands
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136
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van Opbergen CJ, van der Voorn SM, Vos MA, de Boer TP, van Veen TA. Cardiac Ca2+ signalling in zebrafish: Translation of findings to man. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 138:45-58. [DOI: 10.1016/j.pbiomolbio.2018.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/09/2018] [Accepted: 05/04/2018] [Indexed: 02/07/2023]
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137
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Thuringer D, Chanteloup G, Winckler P, Garrido C. The vesicular transfer of CLIC1 from glioblastoma to microvascular endothelial cells requires TRPM7. Oncotarget 2018; 9:33302-33311. [PMID: 30279961 PMCID: PMC6161795 DOI: 10.18632/oncotarget.26048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/16/2018] [Indexed: 01/01/2023] Open
Abstract
Chloride intracellular channel 1 (CLIC1) is highly expressed and secreted by human glioblastoma cells and cell lines such as U87, initiating cell migration and tumor growth. Here, we examined whether CLIC1 could be transferred to human primary microvascular endothelial cells (HMEC). We previously reported that the oncogenic microRNA, miR-5096, increased the release of extracellular vesicles (EVs) by which it increased its own transfer from U87 to surrounding cells. Thus, we also examined its effect on the CLIC1 transfer. In homotypic cultures, miR-5096 did not increase the expression of CLIC1 in U87 nor in HMEC. However, the endothelial CLIC1 level increased after exposure to EVs released by U87, and even more by miR-5096-loaded U87. The EVs-transferred CLIC1 was active in HMEC, promoting endothelial sprouting in matrigel. Cell exposure to EVs induced cytosolic Ca2+ spikes which were dependent on the transient receptor potential melastatin member 7 (TRPM7). TRPM7 silencing prevented Ca2+ spikes and the subsequent CLIC1 delivery into HMEC. Our data suggest that the vesicular transfer of CLIC1 between cells requires TRMP7 expression in recipient endothelial cells. How the vesicular transfer of CLIC1 is modulated in cancer therapy is a future challenge.
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Affiliation(s)
- Dominique Thuringer
- INSERM U1231, Laboratory of Excellence Ligue Nationale contre le Cancer, 21000 Dijon, France.,Université de Bourgogne Franche Comté, 21000 Dijon, France
| | - Gaetan Chanteloup
- INSERM U1231, Laboratory of Excellence Ligue Nationale contre le Cancer, 21000 Dijon, France.,Université de Bourgogne Franche Comté, 21000 Dijon, France
| | - Pascale Winckler
- AgroSup Dijon, PAM UMR, DImaCell Imaging Facility, Université de Bourgogne Franche Comté, 21000 Dijon, France
| | - Carmen Garrido
- INSERM U1231, Laboratory of Excellence Ligue Nationale contre le Cancer, 21000 Dijon, France.,Université de Bourgogne Franche Comté, 21000 Dijon, France.,Centre Georges François Leclerc (CGFL), 21000 Dijon, France
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138
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A study of the mechanisms of excitation–contraction coupling in frog skeletal muscle based on measurements of [Ca2+] transients inside the sarcoplasmic reticulum. J Muscle Res Cell Motil 2018; 39:41-60. [DOI: 10.1007/s10974-018-9497-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/16/2018] [Indexed: 10/28/2022]
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139
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Yip KP, Balasubramanian L, Kan C, Wang L, Liu R, Ribeiro-Silva L, Sham JSK. Intraluminal pressure triggers myogenic response via activation of calcium spark and calcium-activated chloride channel in rat renal afferent arteriole. Am J Physiol Renal Physiol 2018; 315:F1592-F1600. [PMID: 30089032 DOI: 10.1152/ajprenal.00239.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Myogenic contraction of renal arterioles is an important regulatory mechanism for renal blood flow autoregulation. We have previously demonstrated that integrin-mediated mechanical force increases the occurrence of Ca2+ sparks in freshly isolated renal vascular smooth muscle cells (VSMCs). To further test whether the generation of Ca2+ sparks is a downstream signal of mechanotransduction in pressure-induced myogenic constriction, the relationship between Ca2+ sparks and transmural perfusion pressure was investigated in intact VSMCs of pressurized rat afferent arterioles. Spontaneous Ca2+ sparks were found in VSMCs when afferent arterioles were perfused at 80 mmHg. The spark frequency was significantly increased when perfusion pressure was increased to 120 mmHg. A similar increase of spark frequency was also observed in arterioles stimulated with β1-integrin-activating antibody. Moreover, spark frequency was significantly higher in arterioles of spontaneous hypertensive rats at 80 and 120 mmHg. Spontaneous membrane current recorded using whole cell perforated patch in renal VSMCs showed predominant activity of spontaneous transient inward currents instead of spontaneous transient outward currents when holding potential was set close to physiological resting membrane potential. Real-time PCR and immunohistochemistry confirmed the expression of Ca2+-activated Cl- channel (ClCa) TMEM16A in renal VSMCs. Inhibition of TMEM16A with T16Ainh-A01 impaired the pressure-induced myogenic contraction in perfused afferent arterioles. Our study, for the first time to our knowledge, detected Ca2+ sparks in VSMCs of intact afferent arterioles, and their frequencies were positively modulated by the perfusion pressure. Our results suggest that Ca2+ sparks may couple to ClCa channels and trigger pressure-induced myogenic constriction via membrane depolarization.
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Affiliation(s)
- Kay-Pong Yip
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Lavanya Balasubramanian
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Chen Kan
- Department of Industrial, Manufacturing, and System Engineering, University of Texas at Arlington , Arlington, Texas
| | - Lei Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Luisa Ribeiro-Silva
- Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - James S K Sham
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine , Baltimore, Maryland
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140
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Xu X, Balk SP, Isaacs WB, Ma J. Calcium signaling: an underlying link between cardiac disease and carcinogenesis. Cell Biosci 2018; 8:39. [PMID: 29930797 PMCID: PMC5992721 DOI: 10.1186/s13578-018-0236-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 05/25/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Xuehong Xu
- Laboratory of Cell Biology, Genetics and Developmental Biology, Shaanxi Normal University College of Life Sciences, Xi’an, 710062 China
| | - Steven P. Balk
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215 USA
| | | | - Jianjie Ma
- Ohio State University College of Medicine, Columbus, OH 43210 USA
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141
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Arnett DC, Bailey SK, Johnson CK. Exploring the conformations of nitric oxide synthase with fluorescence. Front Biosci (Landmark Ed) 2018; 23:2133-2145. [PMID: 29772550 DOI: 10.2741/4694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multi-domain oxidoreductases are a family of enzymes that catalyze oxidation-reduction reactions through a series of electron transfers. Efficient electron transfer requires a sequence of protein conformations that position electron donor and acceptor domains in close proximity to each other so that electron transfer can occur efficiently. An example is mammalian nitric oxide synthase (NOS), which consists of an N-terminal oxygenase domain containing heme and a C-terminal reductase domain containing NADPH/FAD and FMN subdomains. We describe the use of time-resolved and single-molecule fluorescence to detect and characterize the conformations and conformational dynamics of the neuronal and endothelial isoforms of NOS. Fluorescence signals are provided by a fluorescent dye attached to the Ca2+-signaling protein calmodulin (CaM), which regulates NOS activity. Time-resolved fluorescence decays reveal the presence of at least four underlying conformational states that are differentiated by the extent of fluorescence quenching. Single-molecule fluorescence displays transitions between conformational states on the time scales of milliseconds to seconds. This review describes the type of information available by analysis of time-resolved and single-molecule fluorescence experiments.
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Affiliation(s)
- David C Arnett
- Department of Chemistry, Northwestern College, 101 7th Street SW, Orange City, IA 51041
| | - Sheila K Bailey
- Department of Chemistry, University of Kansas, 1251 Wescoe Drive, Lawrence, KS 66045
| | - Carey K Johnson
- Department of Chemistry, University of Kansas, 1251 Wescoe Drive, Lawrence, KS 66045,
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142
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143
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Chen X, Feng Y, Huo Y, Tan W. The Interplay of Rogue and Clustered Ryanodine Receptors Regulates Ca2+ Waves in Cardiac Myocytes. Front Physiol 2018; 9:393. [PMID: 29755362 PMCID: PMC5932313 DOI: 10.3389/fphys.2018.00393] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/03/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Xudong Chen
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Yundi Feng
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Yunlong Huo
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- PKU-HKUST Shenzhen-Hong Kong Institution, Shenzhen, China
- *Correspondence: Yunlong Huo
| | - Wenchang Tan
- State Key Laboratory of Turbulence and Complex Systems and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- PKU-HKUST Shenzhen-Hong Kong Institution, Shenzhen, China
- Shenzhen Graduate School, Peking University, Shenzhen, China
- Wenchang Tan
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144
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Abstract
Ryanodine-sensitive intracellular Ca2+ channels (RyRs) open upon binding Ca2+ at cytosolic-facing sites. This results in concerted, self-reinforcing opening of RyRs clustered in specialized regions on the membranes of Ca2+ storage organelles (endoplasmic reticulum and sarcoplasmic reticulum), a process that produces Ca2+-induced Ca2+ release (CICR). The process is optimized to achieve large but brief and localized increases in cytosolic Ca2+ concentration, a feature now believed to be critical for encoding the multiplicity of signals conveyed by this ion. In this paper, I trace the path of research that led to a consensus on the physiological significance of CICR in skeletal muscle, beginning with its discovery. I focus on the approaches that were developed to quantify the contribution of CICR to the Ca2+ increase that results in contraction, as opposed to the flux activated directly by membrane depolarization (depolarization-induced Ca2+ release [DICR]). Although the emerging consensus is that CICR plays an important role alongside DICR in most taxa, its contribution in most mammalian muscles appears to be limited to embryogenesis. Finally, I survey the relevance of CICR, confirmed or plausible, to pathogenesis as well as the multiple questions about activation of release channels that remain unanswered after 50 years.
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Affiliation(s)
- Eduardo Ríos
- Section of Cellular Signaling, Department of Physiology and Biophysics, Rush University School of Medicine, Chicago, IL
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145
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Zhou X, Li Z, Wang Z, Chen E, Wang J, Chen F, Jones O, Tan T, Chen S, Takeshima H, Bryant J, Ma J, Xu X. Syncytium calcium signaling and macrophage function in the heart. Cell Biosci 2018; 8:24. [PMID: 29599964 PMCID: PMC5870344 DOI: 10.1186/s13578-018-0222-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/19/2018] [Indexed: 12/20/2022] Open
Abstract
Macrophages are traditionally viewed as a key component of the immunity defense system. Recent studies have identified resident macrophages in multiple organs including the heart, in which the cells perform their crucial role on tissue repair after myocardial infarction (MI). The cardiac-specific macrophages interdigitate with cardiomyocytes particularly at the atrioventricular node region. The integrative communication between macrophage and cardiomyocytes can modulate the contractile function of the heart. Coordinated control of intracellular calcium signaling and intercellular electrical conduction via the syncytium network underlie the synchronized beating of the heart. In this review article, we introduce the concept the syncytium calcium signaling in the cardiomyocytes can modulate gene expression in the resident macrophages and their integration with the cardiomyocytes. The cardiac macrophages originate from bone marrow stem cells, migrate to local via vessel, and settle down as a naturalization process in heart. As the macrophages perform on regulating electrical conduction, and accomplish post MI non-scared completed regeneration or partial regeneration with fibrotic scar at different stage of postnatal development, we understand that multiple functions of cardiac macrophage should carry on with diverse linages. The naturalization process in heart of macrophages to the cardiomyocytes serves important roles to control of electrical signaling and calcium-dependent contractile function of the heart.
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Affiliation(s)
- Xin Zhou
- Laboratory of Cell Biology, Genetics and Developmental Biology, Shaanxi Normal University College of Life Sciences, Xi’an, 710062 People’s Republic of China
- Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Zhongguang Li
- Laboratory of Cell Biology, Genetics and Developmental Biology, Shaanxi Normal University College of Life Sciences, Xi’an, 710062 People’s Republic of China
| | - Zefan Wang
- Laboratory of Cell Biology, Genetics and Developmental Biology, Shaanxi Normal University College of Life Sciences, Xi’an, 710062 People’s Republic of China
| | - Eda Chen
- Virginia Commonwealth University College of Medicine, Richmond, VA 23284 USA
| | - Juan Wang
- Laboratory of Cell Biology, Genetics and Developmental Biology, Shaanxi Normal University College of Life Sciences, Xi’an, 710062 People’s Republic of China
| | | | - Odell Jones
- University of Pennsylvania ULAR, Philadelphia, PA 19144 USA
| | - Tao Tan
- Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Shawn Chen
- Chen Wellness Clinics, Wichita, KS 67219 USA
| | - Hiroshi Takeshima
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501 Japan
| | - Joseph Bryant
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21287 USA
| | - Jianjie Ma
- Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Xuehong Xu
- Laboratory of Cell Biology, Genetics and Developmental Biology, Shaanxi Normal University College of Life Sciences, Xi’an, 710062 People’s Republic of China
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146
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Matsuki K, Kato D, Takemoto M, Suzuki Y, Yamamura H, Ohya S, Takeshima H, Imaizumi Y. Negative regulation of cellular Ca 2+ mobilization by ryanodine receptor type 3 in mouse mesenteric artery smooth muscle. Am J Physiol Cell Physiol 2018. [PMID: 29537866 DOI: 10.1152/ajpcell.00006.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Physiological functions of type 3 ryanodine receptors (RyR3) in smooth muscle (SM) tissues are not well understood, in spite of their wide expression. However, the short isoform of RyR3 is known to be a dominant-negative variant (DN-RyR3), which may negatively regulate functions of both RyR2 and full-length (FL) RyR3 by forming hetero-tetramers. Here, functional roles of RyR3 in the regulation of Ca2+ signaling in mesenteric artery SM cells (MASMCs) were examined using RyR3 homozygous knockout mice (RyR3-/-). Quantitative PCR analyses suggested that the predominant RyR3 subtype in MASMs from wild-type mice (RyR3+/+) was DN-RyR3. In single MASMCs freshly isolated from RyR3-/-, the EC50 of caffeine to induce Ca2+ release was lower than that in RyR3+/+ myocytes. The amplitude and frequency of Ca2+ sparks and spontaneous transient outward currents in MASMCs from RyR3-/- were all larger than those from RyR3+/+. Importantly, mRNA and functional expressions of voltage-dependent Ca2+ channel and large-conductance Ca2+-activated K+ (BK) channel in MASMCs from RyR3-/- were identical to those from RyR3+/+. However, in the presence of BK channel inhibitor, paxilline, the pressure rises induced by BayK8644 in MA vascular beds of RyR3-/- were significantly larger than in those of RyR3+/+. This indicates that the negative feedback effects of BK channel activity on intracellular Ca2+ signaling was enhanced in RyR3-/-. Thus, RyR3, and, in fact, mainly DN-RyR3, via a complex with RyR2 suppresses Ca2+ release and indirectly regulated membrane potential by reducing BK channel activity in MASMCs and presumably can affect the regulation of intrinsic vascular tone.
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Affiliation(s)
- Katsuhito Matsuki
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University , Nagoya , Japan
| | - Daiki Kato
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University , Nagoya , Japan
| | - Masashi Takemoto
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University , Nagoya , Japan
| | - Yoshiaki Suzuki
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University , Nagoya , Japan
| | - Hisao Yamamura
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University , Nagoya , Japan
| | - Susumu Ohya
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University , Nagoya , Japan.,Department of Pharmacology, Graduate School of Medicine, Nagoya City University , Nagoya , Japan
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University , Kyoto , Japan
| | - Yuji Imaizumi
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University , Nagoya , Japan
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147
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Li X, Wu Y, Gao X, Cai M, Shuai J. Wave failure at strong coupling in intracellular Ca^{2+} signaling system with clustered channels. Phys Rev E 2018; 97:012406. [PMID: 29448381 DOI: 10.1103/physreve.97.012406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Indexed: 01/04/2023]
Abstract
As an important intracellular signal, Ca^{2+} ions control diverse cellular functions. In this paper, we discuss the Ca^{2+} signaling with a two-dimensional model in which the inositol 1,4,5-trisphosphate (IP_{3}) receptor channels are distributed in clusters on the endoplasmic reticulum membrane. The wave failure at large Ca^{2+} diffusion coupling is discussed in detail in the model. We show that with varying model parameters the wave failure is a robust behavior with either deterministic or stochastic channel dynamics. We suggest that the wave failure should be a general behavior in inhomogeneous diffusing systems with clustered excitable regions and may occur in biological Ca^{2+} signaling systems.
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Affiliation(s)
- Xiang Li
- Department of Physics, Xiamen University, Xiamen 361005, China.,State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, Xiamen University, Xiamen 361102, China
| | - Yuning Wu
- Department of Physics, Xiamen University, Xiamen 361005, China
| | - Xuejuan Gao
- Department of Physics, Xiamen University, Xiamen 361005, China
| | - Meichun Cai
- Department of Physics, Xiamen University, Xiamen 361005, China
| | - Jianwei Shuai
- Department of Physics, Xiamen University, Xiamen 361005, China.,State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, Xiamen University, Xiamen 361102, China.,Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University, Xiamen 361102, China
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Mustroph J, Wagemann O, Lebek S, Tarnowski D, Ackermann J, Drzymalski M, Pabel S, Schmid C, Wagner S, Sossalla S, Maier LS, Neef S. SR Ca 2+-leak and disordered excitation-contraction coupling as the basis for arrhythmogenic and negative inotropic effects of acute ethanol exposure. J Mol Cell Cardiol 2018; 116:81-90. [PMID: 29410242 DOI: 10.1016/j.yjmcc.2018.02.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 01/23/2018] [Accepted: 02/01/2018] [Indexed: 02/03/2023]
Abstract
AIMS Ethanol has acute negative inotropic and arrhythmogenic effects. The underlying mechanisms, however, are largely unknown. Sarcoplasmic reticulum Ca2+-leak is an important mechanism for reduced contractility and arrhythmias. Ca2+-leak can be induced by oxidative stress and Ca2+/Calmodulin-dependent protein kinase II (CaMKII). Therefore, we investigated the influence of acute ethanol exposure on excitation-contraction coupling in atrial and ventricular cardiomyocytes. METHODS AND RESULTS Isolated human atrial and murine atrial or ventricular cardiomyocytes were preincubated for 30 min and then superfused with control solution or solution containing ethanol. Ethanol had acute negative inotropic and positive lusitropic effects in human atrial muscle strips and murine ventricular cardiomyocytes. Accordingly, Ca2+-imaging indicated lower Ca2+-transient amplitudes and increased SERCA2a activity, while myofilament Ca2+-sensitivity was reduced. SR Ca2+-leak was assessed by measuring Ca2+-sparks. Ethanol induced severe SR Ca2+-leak in human atrial cardiomyocytes (calculated leak: 4.60 ± 0.45 mF/F0 vs 1.86 ± 0.26 in control, n ≥ 80). This effect was dose-dependent, while spontaneous arrhythmogenic Ca2+-waves increased ~5-fold, as investigated in murine cardiomyocytes. Delayed afterdepolarizations, which can result from increased SR Ca2+-leak, were significantly increased by ethanol. Measurements using the reactive oxygen species (ROS) sensor CM-H2DCFDA showed increased ROS-stress in ethanol treated cells. ROS-scavenging with N-acetylcysteine prevented negative inotropic and positive lusitropic effects in human muscle strips. Ethanol-induced Ca2+-leak was abolished in mice with knockout of NOX2 (the main source for ROS in cardiomyocytes). Importantly, mice with oxidation-resistant CaMKII (Met281/282Val mutation) were protected from ethanol-induced Ca2+-leak. CONCLUSION We show for the first time that ethanol acutely induces strong SR Ca2+-leak, also altering excitation-contraction coupling. Acute negative inotropic effects of ethanol can be explained by reduced systolic Ca2+-release. Mechanistically, ROS-production via NOX2 and oxidative activation of CaMKII appear to play central roles. This provides a mechanism for the arrhythmogenic and negative inotropic effects of ethanol and suggests a druggable target (CaMKII).
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Affiliation(s)
- Julian Mustroph
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Olivia Wagemann
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Simon Lebek
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Daniel Tarnowski
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Jasmin Ackermann
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Marzena Drzymalski
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Steffen Pabel
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Christof Schmid
- Dept. of Cardiothoracic Surgery, University Medical Center Regensburg, Regensburg, Germany
| | - Stefan Wagner
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Samuel Sossalla
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Lars S Maier
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Stefan Neef
- Dept. of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany.
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Shen CP, Romero M, Brunelle A, Wolfe C, Dobyns A, Francis M, Taylor MS, Puglisi JL, Longo LD, Zhang L, Wilson CG, Wilson SM. Long-term high-altitude hypoxia influences pulmonary arterial L-type calcium channel-mediated Ca 2+ signals and contraction in fetal and adult sheep. Am J Physiol Regul Integr Comp Physiol 2017; 314:R433-R446. [PMID: 29167165 DOI: 10.1152/ajpregu.00154.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long-term hypoxia (LTH) has a profound effect on pulmonary arterial vasoconstriction in the fetus and adult. Dysregulation in Ca2+ signaling is important during the development of LTH-induced pulmonary hypertension. In the present study, we tested the hypothesis that L-type Ca2+ channels (CaL), which are voltage dependent and found in smooth, skeletal, and cardiac muscle, are important in the adaptation of pulmonary arterial contractions in postnatal maturation and in response to LTH. Pulmonary arteries were isolated from fetal or adult sheep maintained at low or high altitude (3,801 m) for >100 days. The effects were measured using an L-type Ca2+ channel opener FPL 64176 (FPL) in the presence or absence of an inhibitor, Nifedipine (NIF) on arterial contractions, intracellular Ca2+ oscillations, and ryanodine receptor-driven Ca2+ sparks. FPL induced pulmonary arterial contractions in all groups were sensitive to NIF. However, when compared with 125 mM K+, FPL contractions were greater in fetuses than in adults. FPL reduced Ca2+ oscillations in myocytes of adult but not fetal arteries, independently of altitude. The FPL effects on Ca2+ oscillations were reversed by NIF in myocytes of hypoxic but not normoxic adults. FPL failed to enhance Ca2+ spark frequency and had little impact on spatiotemporal firing characteristics. These data suggest that CaL-dependent contractions are largely uncoupled from intracellular Ca2+ oscillations and the development of Ca2+ sparks. This raises questions regarding the coupling of pulmonary arterial contractility to membrane depolarization, attendant CaL facilitation, and the related associations with the activation of Ca2+ oscillations and Ca2+ sparks.
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Affiliation(s)
- Christine P Shen
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine , Loma Linda, California
| | - Monica Romero
- Advanced Imaging and Microscopy Core, Loma Linda University School of Medicine , Loma Linda, California
| | - Alexander Brunelle
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine , Loma Linda, California
| | - Craig Wolfe
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine , Loma Linda, California
| | - Abigail Dobyns
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine , Loma Linda, California
| | - Michael Francis
- Department of Physiology, University of South Alabama College of Medicine , Mobile, Alabama
| | - Mark S Taylor
- Department of Physiology, University of South Alabama College of Medicine , Mobile, Alabama
| | - Jose L Puglisi
- Department of Biostatistics, California Northstate University School of Medicine , Elk Grove, California
| | - Lawrence D Longo
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine , Loma Linda, California
| | - Lubo Zhang
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine , Loma Linda, California
| | - Christopher G Wilson
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine , Loma Linda, California
| | - Sean M Wilson
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda University School of Medicine , Loma Linda, California
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