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Fernández-Morales JC, Xia Y, Rienzo TJ, Zhang XH, Morad M. Mutation in RyR2-FKBP Binding site alters Ca 2+ signaling modestly but increases "arrhythmogenesis" in human stem cells derived cardiomyocytes. Cell Calcium 2022; 101:102500. [PMID: 34813985 PMCID: PMC8752506 DOI: 10.1016/j.ceca.2021.102500] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 01/03/2023]
Abstract
AIMS To gain insights into FKBP regulation of cardiac ryanodine receptor (RyR2) and Ca2+ signaling, we introduced the point mutation (N771D-RyR2) corresponding to skeletal muscle mutation (N760D-RyR1) associated with central core disease (CCD) via CRISPR/Cas9 gene-editing in the RyR2 FKBP binding site expressed in human induced pluripotent stem cell-derived cardiomyocytes (hiPSCCMs). Patients inflicted with CCD and other hereditary skeletal muscle diseases often show higher incidence of atrial or ventricular arrhythmias. METHODS AND RESULTS Ca2+ imaging of voltage-clamped N771D-RyR2 mutant compared to WT hiPSCCMs showed: (1) ∼30% suppressed ICa with no significant changes in the gating kinetics of ICa; (2) 29% lower SR Ca2+ content and 33% lower RyR2 Ca2+ leak; (3) higher CICR gain and 30-35% increased efficiency of ICa-triggered Ca2±release; (4) higher incidence of aberrant SR Ca2+ releases, DADs, and Ca2+ sparks; (5) no change in fractional Ca2+-release, action potential morphology, sensitivity to isoproterenol, and sarcomeric FKBP-binding pattern. CONCLUSIONS The more frequent spontaneous Ca2+ releases and longer Ca2+ sparks underlie the increased incidence of DADs and cellular arrhythmogenesis of N771D-RyR2 mutant. The smaller RyR2 Ca2±leak and SR content result from suppressed ICathat is compensated by higher CICR gain.
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Affiliation(s)
| | - Yanli Xia
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Taylor J. Rienzo
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Xiao-Hua Zhang
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA
| | - Martin Morad
- Cardiac Signaling Center of MUSC, USC and Clemson University, Charleston, SC, USA.,Department of Pharmacology, Georgetown University Medical Center, Washington, DC, USA
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2
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Yang L, Fomina AF. Ca 2+ influx and clearance at hyperpolarized membrane potentials modulate spontaneous and stimulated exocytosis in neuroendocrine cells. Cell Calcium 2020; 87:102184. [PMID: 32151786 DOI: 10.1016/j.ceca.2020.102184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/10/2020] [Accepted: 02/21/2020] [Indexed: 01/09/2023]
Abstract
Neuroendocrine adrenal chromaffin cells release neurohormones catecholamines in response to Ca2+ entry via voltage-gated Ca2+ channels (VGCCs). Adrenal chromaffin cells also express non-voltage-gated channels, which may conduct Ca2+ at negative membrane potentials, whose role in regulation of exocytosis is poorly understood. We explored how modulation of Ca2+ influx at negative membrane potentials affects basal cytosolic Ca2+ concentration ([Ca2+]i) and exocytosis in metabolically intact voltage-clamped bovine adrenal chromaffin cells. We found that in these cells, Ca2+ entry at negative membrane potentials is balanced by Ca2+ extrusion by the Na+/Ca2+ exchanger and that this balance can be altered by membrane hyperpolarization or stimulation with an inflammatory hormone bradykinin. Membrane hyperpolarization or application of bradykinin augmented Ca2+-carrying current at negative membrane potentials, elevated basal [Ca2+]i, and facilitated synchronous exocytosis evoked by the small amounts of Ca2+ injected into the cell via VGCCs (up to 20 pC). Exocytotic responses evoked by the injections of the larger amounts of Ca2+ via VGCCs (> 20 pC) were suppressed by preceding hyperpolarization. In the absence of Ca2+ entry via VGCCs and Ca2+ extrusion via the Na+/Ca2+ exchanger, membrane hyperpolarization induced a significant elevation in [Ca2+]i and asynchronous exocytosis. Our results indicate that physiological interferences, such as membrane hyperpolarization and/or activation of non-voltage-gated Ca2+ channels, modulate basal [Ca2+]i and, consequently, segregation of exocytotic vesicles and their readiness to be released spontaneously and in response to Ca2+ entry via VGCCs. These mechanisms may play role in homeostatic plasticity of neuronal and endocrine cells.
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Affiliation(s)
- Lukun Yang
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, 95616, USA; Department of Anesthesiology, The 5th Affiliated Hospital of SUN YAT-SEN University, Zhuhai, 519000, China.
| | - Alla F Fomina
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, 95616, USA.
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de Diego AMG, García AG. Altered exocytosis in chromaffin cells from mouse models of neurodegenerative diseases. Acta Physiol (Oxf) 2018; 224:e13090. [PMID: 29742321 DOI: 10.1111/apha.13090] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 04/19/2018] [Accepted: 04/25/2018] [Indexed: 12/26/2022]
Abstract
Chromaffin cells from the adrenal gland (CCs) have extensively been used to explore the molecular structure and function of the exocytotic machinery, neurotransmitter release and synaptic transmission. The CC is integrated in the sympathoadrenal axis that helps the body maintain homoeostasis during both routine life and in acute stress conditions. This function is exquisitely controlled by the cerebral cortex and the hypothalamus. We propose the hypothesis that damage undergone by the brain during neurodegenerative diseases is also affecting the neurosecretory function of adrenal medullary CCs. In this context, we review here the following themes: (i) How the discharge of catecholamines is centrally and peripherally regulated at the sympathoadrenal axis; (ii) which are the intricacies of the amperometric techniques used to study the quantal release of single-vesicle exocytotic events; (iii) which are the alterations of the exocytotic fusion pore so far reported, in CCs of mouse models of neurodegenerative diseases; (iv) how some proteins linked to neurodegenerative pathologies affect the kinetics of exocytotic events; (v) finally, we try to integrate available data into a hypothesis to explain how the centrally originated neurodegenerative diseases may alter the kinetics of single-vesicle exocytotic events in peripheral adrenal medullary CCs.
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Affiliation(s)
- A. M. García de Diego
- Instituto Teófilo Hernando; Universidad Autónoma de Madrid; Madrid Spain
- Instituto de Investigación Sanitaria; Hospital Universitario de la Princesa; Universidad Autónoma de Madrid; Madrid Spain
- DNS Neuroscience; Parque Científico de Madrid; Madrid Spain
| | - A. García García
- Instituto Teófilo Hernando; Universidad Autónoma de Madrid; Madrid Spain
- Instituto de Investigación Sanitaria; Hospital Universitario de la Princesa; Universidad Autónoma de Madrid; Madrid Spain
- DNS Neuroscience; Parque Científico de Madrid; Madrid Spain
- Departamento de Farmacología y Terapéutica; Facultad de Medicina; Universidad Autónoma de Madrid; Madrid Spain
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Musial DC, Bomfim GH, Arranz-Tagarro JA, Méndez-López I, Miranda-Ferreira R, Jurkiewicz A, Jurkiewicz NH, García AG, Padín JF. Altered mitochondrial function, calcium signaling, and catecholamine release in chromaffin cells of diabetic and SHR rats. Eur J Pharmacol 2017; 815:416-426. [DOI: 10.1016/j.ejphar.2017.09.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 09/12/2017] [Accepted: 09/28/2017] [Indexed: 11/25/2022]
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Regulation by L channels of Ca(2+)-evoked secretory responses in ouabain-treated chromaffin cells. Pflugers Arch 2016; 468:1779-92. [PMID: 27558258 DOI: 10.1007/s00424-016-1866-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/21/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
It is known that the sustained depolarisation of adrenal medullary bovine chromaffin cells (BCCs) with high K(+) concentrations produces an initial sharp catecholamine release that subsequently fades off in spite depolarisation persists. Here, we have recreated a sustained depolarisation condition of BCCs by treating them with the Na(+)/K(+) ATPase blocker ouabain; in doing so, we searched experimental conditions that permitted the development of a sustained long-term catecholamine release response that could be relevant during prolonged stress. BCCs were perifused with nominal 0Ca(2+) solution, and secretion responses were elicited by intermittent application of short 2Ca(2+) pulses (Krebs-HEPES containing 2 mM Ca(2+)). These pulses elicited a biphasic secretory pattern with an initial 30-min period with secretory responses of increasing amplitude and a second 30-min period with steady-state, non-inactivating responses. The initial phase was not due to gradual depolarisation neither to gradual increases of the cytosolic calcium transients ([Ca(2+)]c) elicited by 2Ca(2+) pulses in BBCs exposed to ouabain; both parameters increased soon after ouabain addition. Νifedipine blocked these responses, and FPL64176 potentiated them, suggesting that they were triggered by Ca(2+) entry through non-inactivating L-type calcium channels. This was corroborated by nifedipine-evoked blockade of the L-type Ca(2+) channel current and the [Ca(2+)]c transients elicited by 2Ca(2+) pulses. Furthermore, the plasmalemmal Na(+)/Ca(2+) exchanger (NCX) blocker SEA0400 caused a mild inhibition followed by a large rebound increase of the steady-state secretory responses. We conclude that these two phases of secretion are mostly contributed by Ca(2+) entry through L calcium channels, with a minor contribution of Ca(2+) entry through the reverse mode of the NCX.
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Caricati-Neto A, Padín JF, Silva-Junior ED, Fernández-Morales JC, de Diego AMG, Jurkiewicz A, García AG. Novel features on the regulation by mitochondria of calcium and secretion transients in chromaffin cells challenged with acetylcholine at 37°C. Physiol Rep 2013; 1:e00182. [PMID: 24744861 PMCID: PMC3970745 DOI: 10.1002/phy2.182] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 11/01/2013] [Indexed: 01/14/2023] Open
Abstract
From experiments performed at room temperature, we know that the buffering of Ca2+ by mitochondria contributes to the shaping of the bulk cytosolic calcium transient ([Ca2+]c) and secretion transients of chromaffin cells stimulated with depolarizing pulses. We also know that the mitochondrial Ca2+ transporters and the release of catecholamine are faster at 37°C with respect to room temperature. Therefore, we planned this investigation to gain further insight into the contribution of mitochondrial Ca2+ buffering to the shaping of [Ca2+]c and catecholamine release transients, using some novel experimental conditions that have not been yet explored namely: (1) perifusion of bovine chromaffin cells (BCCs) with saline at 37°C and their repeated challenging with the physiological neurotransmitter acetylcholine (ACh); (2) separate blockade of mitochondrial Ca2+ uniporter (mCUP) with Ru360 or the mitochondrial Na+/Ca2+ exchanger (mNCX) with CGP37157; (3) full blockade of the mitochondrial Ca2+ cycling (mCC) by the simultaneous inhibition of the mCUP and the mNCX. Ru360 caused a pronounced delay of [Ca2+]c clearance and augmented secretion. In contrast, CGP37157 only caused a tiny delay of [Ca2+]c clearance and a mild decrease in secretion. The mCC resulting in continued Ca2+ uptake and its release back into the cytosol was interrupted by combined Ru360 + CGP37157 (Ru/CGP), the protonophore carbonyl cyanide‐p‐trifluoromethoxyphenylhydrazone, or combined oligomycin + rotenone (O/R); these three treatments caused a mild but sustained elevation of basal [Ca2+]c that, however, was not accompanied by a parallel increase in basal secretion. Nevertheless, all treatments caused a pronounced augmentation of ACh‐induced secretion, with minor changes of the ACh‐induced [Ca2+]c transients. Combined Ru/CGP did not alter the resting membrane potential in current‐clamped cells. Additionally, Ru/CGP did not increase basal [Ca2+]c near subplasmalemmal sites and caused a mild decrease in the size of the readily releasable vesicle pool. Our results provide new functional features in support of the view that in BCCs there are two subpopulations of mitochondria, M1 underneath the plasmalemma nearby exocytotic sites and M2 at the core cell nearby vesicle transport sites. While M1 serves to shape the ACh‐elicited exocytotic response through its efficient Ca2+ removal by the mCUP, M2 shapes the lower [Ca2+]c elevations required for new vesicle supply to the exocytotic machinery, from the large reserve vesicle pool at the cell core. The mCUP of the M1 pool seems to play a more prominent role in controlling the ACh responses, in comparison with the mNCX. Regulation by mitochondria of exocytosis at 37°C.
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Affiliation(s)
- Afonso Caricati-Neto
- Departamento de Farmacología, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Juan-Fernando Padín
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, Madrid, 28029, Spain ; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029Madrid, Spain
| | - Edilson-Dantas Silva-Junior
- Departamento de Farmacología, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - José-Carlos Fernández-Morales
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, Madrid, 28029, Spain ; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029Madrid, Spain
| | - Antonio-Miguel G de Diego
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, Madrid, 28029, Spain ; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029Madrid, Spain
| | - Aron Jurkiewicz
- Departamento de Farmacología, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Antonio G García
- Instituto Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, Madrid, 28029, Spain ; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 4, 28029Madrid, Spain ; Servicio de Farmacología Clínica, Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, C/Diego de León, 62, Madrid, 28006, Spain
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García-Sancho J. The coupling of plasma membrane calcium entry to calcium uptake by endoplasmic reticulum and mitochondria. J Physiol 2013; 592:261-8. [PMID: 23798493 DOI: 10.1113/jphysiol.2013.255661] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cross-talk between organelles and plasma membrane Ca(2+) channels is essential for modulation of the cytosolic Ca(2+) ([Ca(2+)]C) signals, but such modulation may differ among cells. In chromaffin cells Ca(2+) entry through voltage-operated channels induces calcium release from the endoplasmic reticulum (ER) that amplifies the signal. [Ca(2+)]C microdomains as high as 20-50 μm are sensed by subplasmalemmal mitochondria, which accumulate large amounts of Ca(2+) through the mitochondrial Ca(2+) uniporter (MCU). Mitochondria confine the high-Ca(2+) microdomains (HCMDs) to beneath the plasma membrane, where exocytosis of secretory vesicles happens. Cell core [Ca(2+)]C is much smaller (1-2 μm). By acting as a Ca(2+) sink, mitochondria stabilise the HCMD in space and time. In non-excitable HEK293 cells, activation of store-operated Ca(2+) entry, triggered by ER Ca(2+) emptying, also generated subplasmalemmal HCMDs, but, in this case, most of the Ca(2+) was taken up by the ER rather than by mitochondria. The smaller size of the [Ca(2+)]C peak in this case (about 2 μm) may contribute to this outcome, as the sarco-endoplasmic reticulum Ca(2+) ATPase has much higher Ca(2+) affinity than MCU. It is also possible that the relative positioning of organelles, channels and effectors, as well as cytoskeleton and accessory proteins plays an important role.
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