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Nguyen HT, Noriega Polo C, Wiederkehr A, Wollheim CB, Park KS. CDN1163, an activator of sarco/endoplasmic reticulum Ca 2+ ATPase, up-regulates mitochondrial functions and protects against lipotoxicity in pancreatic β-cells. Br J Pharmacol 2023; 180:2762-2776. [PMID: 37277321 DOI: 10.1111/bph.16160] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 05/10/2023] [Accepted: 05/12/2023] [Indexed: 06/07/2023] Open
Abstract
BACKGROUND AND PURPOSE High levels of Ca2+ in the endoplasmic reticulum (ER), established by the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA), are required for protein folding and cell signalling. Excessive ER Ca2+ release or decreased SERCA activity induces unfolded protein accumulation and ER stress in pancreatic β-cells, leading to defective insulin secretion and diabetes. Here we have investigated the consequences of enhancing ER Ca2+ uptake on β-cell survival and function. EXPERIMENTAL APPROACH The effects of SERCA activator, CDN1163, on Ca2+ homeostasis, protein expression, mitochondrial activities, insulin secretion, and lipotoxicity have been studied in mouse pancreatic β-cells and MIN6 cells. KEY RESULTS CDN1163, increased insulin synthesis and exocytosis from islets. CDN1163 also increased the sensitivity of the cytosolic Ca2+ oscillation response to glucose and potentiated it in dispersed and sorted β-cells. CDN1163 augmented the ER and mitochondrial Ca2+ content, the mitochondrial membrane potential, respiration, and ATP synthesis. CDN1163 up-regulated expression of inositol 1,4,5-trisphosphate receptors and antioxidant enzymes, and mitochondrial biogenesis, including peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α). Overexpression of SERCA2a or 2b replicated the effects of CDN1163, while knockdown of SERCA2 abolished the stimulatory actions of CDN1163. In palmitate-treated β-cells, CDN1163 prevented ER Ca2+ depletion, mitochondrial dysfunction, cytosolic and mitochondrial oxidative stress, defective insulin secretion, and apoptotic cell death. CONCLUSIONS AND IMPLICATIONS Activation of SERCA enhanced mitochondrial bioenergetics and antioxidant capability, suppressing the cytotoxic effects of palmitate. Our results suggest that targeting SERCA could be a novel therapeutic strategy to protect β-cells from lipotoxicity and the development of Type 2 diabetes.
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Affiliation(s)
- Ha Thu Nguyen
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, South Korea
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | - Carlos Noriega Polo
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, South Korea
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | | | - Claes B Wollheim
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Kyu-Sang Park
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, South Korea
- Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, South Korea
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Papp B, Launay S, Gélébart P, Arbabian A, Enyedi A, Brouland JP, Carosella ED, Adle-Biassette H. Endoplasmic Reticulum Calcium Pumps and Tumor Cell Differentiation. Int J Mol Sci 2020; 21:ijms21093351. [PMID: 32397400 PMCID: PMC7247589 DOI: 10.3390/ijms21093351] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/01/2020] [Accepted: 05/02/2020] [Indexed: 12/21/2022] Open
Abstract
Endoplasmic reticulum (ER) calcium homeostasis plays an essential role in cellular calcium signaling, intra-ER protein chaperoning and maturation, as well as in the interaction of the ER with other organelles. Calcium is accumulated in the ER by sarco/endoplasmic reticulum calcium ATPases (SERCA enzymes) that generate by active, ATP-dependent transport, a several thousand-fold calcium ion concentration gradient between the cytosol (low nanomolar) and the ER lumen (high micromolar). SERCA enzymes are coded by three genes that by alternative splicing give rise to several isoforms, which can display isoform-specific calcium transport characteristics. SERCA expression levels and isoenzyme composition vary according to cell type, and this constitutes a mechanism whereby ER calcium homeostasis is adapted to the signaling and metabolic needs of the cell, depending on its phenotype, its state of activation and differentiation. As reviewed here, in several normal epithelial cell types including bronchial, mammary, gastric, colonic and choroid plexus epithelium, as well as in mature cells of hematopoietic origin such as pumps are simultaneously expressed, whereas in corresponding tumors and leukemias SERCA3 expression is selectively down-regulated. SERCA3 expression is restored during the pharmacologically induced differentiation of various cancer and leukemia cell types. SERCA3 is a useful marker for the study of cell differentiation, and the loss of SERCA3 expression constitutes a previously unrecognized example of the remodeling of calcium homeostasis in tumors.
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Affiliation(s)
- Bela Papp
- Institut National de la Santé et de la Recherche Médicale, UMR U976, Institut Saint-Louis, 75010 Paris, France
- Institut de Recherche Saint-Louis, Hôpital Saint-Louis, Université de Paris, 75010 Paris, France
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, 75010 Paris, France;
- Correspondence: or
| | - Sophie Launay
- EA481, UFR Santé, Université de Bourgogne Franche-Comté, 25000 Besançon, France;
| | - Pascal Gélébart
- Department of Clinical Science-Hematology Section, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway;
| | - Atousa Arbabian
- Laboratoire d’Innovation Vaccins, Institut Pasteur de Paris, 75015 Paris, France;
| | - Agnes Enyedi
- Second Department of Pathology, Semmelweis University, 1091 Budapest, Hungary;
| | - Jean-Philippe Brouland
- Institut Universitaire de Pathologie, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland;
| | - Edgardo D. Carosella
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, 75010 Paris, France;
| | - Homa Adle-Biassette
- AP-HP, Service d’Anatomie et Cytologie Pathologiques, Hôpital Lariboisière, 75010 Paris, France;
- Université de Paris, NeuroDiderot, Inserm UMR 1141, 75019 Paris, France
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Marin L, Silva HBF, Damin G, Ignacio-Souza LM, Reis SRDL, de Oliveira CAM, Ribeiro RA, Reis MADB, Latorraca MQ, Ferreira F, Arantes VC. Nutritional recovery from a low-protein diet during pregnancy does not restore the kinetics of insulin secretion and Ca 2+ or alterations in the cAMP/PKA and PLC/PKC pathways in islets from adult rats. Appl Physiol Nutr Metab 2019; 43:1257-1267. [PMID: 29758169 DOI: 10.1139/apnm-2017-0629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the insulin release induced by glucose, the Ca2+ oscillatory pattern, and the cyclic AMP (cAMP)/protein kinase A (PKA) and phospholipase C (PLC)/protein kinase C (PKC) pathways in islets from adult rats that were reared under diets with 17% protein (C) or 6% protein (LP) during gestation, suckling, and after weaning and in rats receiving diets with 6% protein during gestation and 17% protein after birth (R). First-phase glucose-induced insulin secretion was reduced in LP and R islets, and the second phase was partially restored in the R group. Glucose stimulation did not modify intracellular Ca2+ concentration, but it reduced the Ca2+ oscillatory frequency in the R group compared with the C group. Intracellular cAMP concentration was higher and PKA-Cα expression was lower in the R and LP groups compared with the C group. The PKCα content in islets from R rats was lower than that in C and LP rats. Thus, nutritional recovery from a low-protein diet during fetal life did not repair the kinetics of insulin release, impaired Ca2+ handling, and altered the cAMP/PKA and PLC/PKC pathways.
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Affiliation(s)
- Leonardo Marin
- a Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá-MT, 78060-900, Brazil
| | | | - Gabriela Damin
- a Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá-MT, 78060-900, Brazil
| | | | | | | | - Rosane Aparecida Ribeiro
- d Universidade Federal do Rio de Janeiro, Núcleo em Ecologia e desenvolvimento socioambiental, Rio de Janeiro-RJ, 21941-901, Brazil
| | | | | | - Fabiano Ferreira
- e Departamento de Fisiologia e Farmacologia da Universidade Federal de Pernambuco, Recife-PE, 50670-901, Brazil
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4
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Jha A, Adlakha N. Two-dimensional finite element model to study unsteady state Ca2+ diffusion in neuron involving ER LEAK and SERCA. INT J BIOMATH 2015. [DOI: 10.1142/s1793524515500023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this paper, finite element approach using two-dimensional unsteady state problem has been developed to study radial and angular calcium diffusion problem in neurons. Calcium is responsible messenger for transmitting information in communication process between neurons. The most important Ca 2+ binding proteins for the dynamics of Ca 2+ is itself buffer and other physiological parameters are located in Ca 2+ stores. In this study, the model incorporates the physiological parameters like diffusion coefficient, receptors, exogenous buffers etc. Appropriate boundary conditions have been framed in view of the physiological conditions. Computer simulations in MATLAB 7.11 are employed to investigate mathematical models of reaction–diffusion equation, the details of the implementation can heavily affect the numerical solutions and, thus, the outcome simulated on Core(TM) i3 CPU M 330 @ 2.13 GHz processing speed and 3 GB memory.
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Affiliation(s)
- Amrita Jha
- Department of Science and Humanities, Indus University, Ahmedabad, India
| | - Neeru Adlakha
- Department of Applied Mathematics and Humanities, S. V. National Institute of Technology, Surat, India
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5
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Regulation of SERCA pumps expression in diabetes. Cell Calcium 2014; 56:302-10. [DOI: 10.1016/j.ceca.2014.09.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 11/22/2022]
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6
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Ait-Ghezali L, Arbabian A, Jeibmann A, Hasselblatt M, Hallaert GG, Van den Broecke C, Gray F, Brouland JP, Varin-Blank N, Papp B. Loss of endoplasmic reticulum calcium pump expression in choroid plexus tumours. Neuropathol Appl Neurobiol 2014; 40:726-35. [DOI: 10.1111/nan.12098] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 11/08/2013] [Indexed: 01/15/2023]
Affiliation(s)
- Lamia Ait-Ghezali
- Institut National de la Santé et de la Recherche Médicale; UMR U978; Bobigny France
- Université Paris-13; PRES Sorbonne Paris-Cité; Bobigny France
| | | | - Astrid Jeibmann
- Institute of Neuropathology; University Hospital Münster; Münster Germany
| | - Martin Hasselblatt
- Institute of Neuropathology; University Hospital Münster; Münster Germany
| | | | | | - Françoise Gray
- AP-HP; Service d'Anatomie et Cytologie Pathologiques; Hôpital Lariboisière; Paris France
| | - Jean-Philippe Brouland
- AP-HP; Service d'Anatomie et Cytologie Pathologiques; Hôpital Lariboisière; Paris France
| | - Nadine Varin-Blank
- Institut National de la Santé et de la Recherche Médicale; UMR U978; Bobigny France
- Université Paris-13; PRES Sorbonne Paris-Cité; Bobigny France
| | - Bela Papp
- Institut National de la Santé et de la Recherche Médicale; UMR U978; Bobigny France
- Université Paris-13; PRES Sorbonne Paris-Cité; Bobigny France
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Abstract
Background Insulin secreted by pancreatic islet β-cells is the principal regulating hormone of glucose metabolism and plays a key role in controlling glucose level in blood. Impairment of the pancreatic islet function may cause glucose to accumulate in blood, and result in diabetes mellitus. Recent studies have shown that mitochondrial dysfunction has a strong negative effect on insulin secretion. Methods In order to study the cause of dysfunction of pancreatic islets, a multiple cell model containing healthy and unhealthy cells is proposed based on an existing single cell model. A parameter that represents the function of mitochondria is modified for unhealthy cells. A 3-D hexagonal lattice structure is used to model the spatial differences among β-cells in a pancreatic islet. The β-cells in the model are connected through direct electrical connections between neighboring β-cells. Results The simulation results show that the low ratio of total mitochondrial volume over cytoplasm volume per β-cell is a main reason that causes some mitochondria to lose their function. The results also show that the overall insulin secretion will be seriously disrupted when more than 15% of the β-cells in pancreatic islets become unhealthy. Conclusion Analysis of the model shows that the insulin secretion can be reinstated by increasing the glucokinase level. This new discovery sheds light on antidiabetic medication.
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Papp B, Brouland JP, Arbabian A, Gélébart P, Kovács T, Bobe R, Enouf J, Varin-Blank N, Apáti A. Endoplasmic reticulum calcium pumps and cancer cell differentiation. Biomolecules 2012; 2:165-86. [PMID: 24970132 PMCID: PMC4030869 DOI: 10.3390/biom2010165] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Revised: 02/14/2012] [Accepted: 02/17/2012] [Indexed: 12/23/2022] Open
Abstract
The endoplasmic reticulum (ER) is a major intracellular calcium storage pool and a multifunctional organelle that accomplishes several calcium-dependent functions involved in many homeostatic and signaling mechanisms. Calcium is accumulated in the ER by Sarco/Endoplasmic Reticulum Calcium ATPase (SERCA)-type calcium pumps. SERCA activity can determine ER calcium content available for intra-ER functions and for calcium release into the cytosol, and can shape the spatiotemporal characteristics of calcium signals. SERCA function therefore constitutes an important nodal point in the regulation of cellular calcium homeostasis and signaling, and can exert important effects on cell growth, differentiation and survival. In several cell types such as cells of hematopoietic origin, mammary, gastric and colonic epithelium, SERCA2 and SERCA3-type calcium pumps are simultaneously expressed, and SERCA3 expression levels undergo significant changes during cell differentiation, activation or immortalization. In addition, SERCA3 expression is decreased or lost in several tumor types when compared to the corresponding normal tissue. These observations indicate that ER calcium homeostasis is remodeled during cell differentiation, and may present defects due to decreased SERCA3 expression in tumors. Modulation of the state of differentiation of the ER reflected by SERCA3 expression constitutes an interesting new aspect of cell differentiation and tumor biology.
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Affiliation(s)
- Béla Papp
- Institut National de la Santé et de la Recherche Médicale, Inserm UMR U978, UFR SMBH Université Paris 13-Paris Nord, 74, rue Marcel Cachin 93000 Bobigny, France.
| | - Jean-Philippe Brouland
- Service d'Anatomie et Cytologie Pathologique, Hôpital Lariboisière, 1, rue Ambroise Paré, 75010 Paris, France.
| | - Atousa Arbabian
- Inserm UMR U 940, IUH Université Paris 7-Paris Diderot, 16, rue de la Grange aux Belles, 75010 Paris, France.
| | - Pascal Gélébart
- Department of Laboratory Medicine and Pathology, Cross Cancer Institute and University of Alberta, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada.
| | - Tünde Kovács
- Semmelweis University, Department of Medical Biochemistry, Tűzoltó u. 37-47, H-1094-Budapest, Hungary.
| | - Régis Bobe
- Inserm UMR U770, Université Paris-Sud 11. 80, rue du Général Leclerc, 94276 Le Kremlin-Bicêtre, France.
| | - Jocelyne Enouf
- Inserm UMR U689, Université Paris 7-Paris Diderot, Hôpital Lariboisière, 1, rue Ambroise Paré, 75010 Paris, France.
| | - Nadine Varin-Blank
- Institut National de la Santé et de la Recherche Médicale, Inserm UMR U978, UFR SMBH Université Paris 13-Paris Nord, 74, rue Marcel Cachin 93000 Bobigny, France.
| | - Agota Apáti
- Membrane Research Group of the Hungarian Academy of Sciences, Diószegi út 64, H-1113-Budapest, Hungary.
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9
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Papp B, Brouland JP. Altered Endoplasmic Reticulum Calcium Pump Expression during Breast Tumorigenesis. BREAST CANCER-BASIC AND CLINICAL RESEARCH 2011; 5:163-74. [PMID: 21863130 PMCID: PMC3153116 DOI: 10.4137/bcbcr.s7481] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Endoplasmic reticulum calcium homeostasis is involved in several essential cell functions including cell proliferation, protein synthesis, stress responses or secretion. Calcium uptake into the endoplasmic reticulum is performed by Sarco/Endoplasmic Reticulum Calcium ATPases (SERCA enzymes). In order to study endoplasmic reticulum calcium homeostasis in situ in mammary tissue, in this work SERCA3 expression was investigated in normal breast and in its benign and malignant lesions in function of the cell type, degree of malignancy, and histological and molecular parameters of the tumors. Our data indicate, that although normal breast acinar epithelial cells express SERCA3 abundantly, its expression is strongly decreased already in very early non-malignant epithelial lesions such as adenosis, and remains low in lobular carcinomas. Whereas normal duct epithelium expresses significant amounts of SERCA3, its expression is decreased in several benign ductal lesions, as well as in ductal adenocarcinoma. The loss of SERCA3 expression is correlated with Elston-Ellis grade, negative hormone receptor expression or triple negative status in ductal carcinomas. The concordance between decreased SERCA3 expression and several histological, as well as molecular markers of ductal carcinogenesis indicates that endoplasmic reticulum calcium homeostasis is remodeled during tumorigenesis in the breast epithelium.
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Affiliation(s)
- Béla Papp
- Institut National de la Santé et de la Recherche Médicale, Inserm UMR-S 940, Institut Universitaire d'Hématologie, 16, rue de la Grange aux Belles, 75010 Paris, Université Paris Diderot, Sorbonne Paris Cité
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10
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Arbabian A, Brouland JP, Gélébart P, Kovàcs T, Bobe R, Enouf J, Papp B. Endoplasmic reticulum calcium pumps and cancer. Biofactors 2011; 37:139-49. [PMID: 21674635 DOI: 10.1002/biof.142] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 12/15/2010] [Indexed: 12/11/2022]
Abstract
Endoplasmic reticulum calcium homeostasis is involved in a multitude of signaling, as well as "house-keeping" functions that control cell growth, differentiation or apoptosis in every human/eukaryotic cell. Calcium is actively accumulated in the endoplasmic reticulum by Sarco/Endoplasmic Reticulum Calcium transport ATPases (SERCA enzymes). SERCA-dependent calcium transport is the only calcium uptake mechanism in this organelle, and therefore the regulation of SERCA function by the cell constitutes a key mechanism to adjust calcium homeostasis in the endoplasmic reticulum depending on the cell type and its state of differentiation. The direct pharmacological modulation of SERCA activity affects cell differentiation and survival. SERCA expression levels can undergo significant changes during cell differentiation or tumorigenesis, leading to modified endoplasmic reticulum calcium storage. In several cell types such as cells of hematopoietic origin or various epithelial cells, two SERCA genes (SERCA2 and SERCA3) are simultaneously expressed. Expression levels of SERCA3, a lower calcium affinity calcium pump are highly variable. In several cell systems SERCA3 expression is selectively induced during differentiation, whereas during tumorigenesis and blastic transformation SERCA3 expression is decreased. These observations point at the existence of a cross-talk, via the regulation of SERCA3 levels, between endoplasmic reticulum calcium homeostasis and the control of cell differentiation, and show that endoplasmic reticulum calcium homeostasis itself can undergo remodeling during differentiation. The investigation of the anomalies of endoplasmic reticulum differentiation in tumor and leukemia cells may be useful for a better understanding of the contribution of calcium signaling to the establishment of malignant phenotypes.
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Affiliation(s)
- Atousa Arbabian
- Institut National de la Santé et de la Recherche Médicale, Inserm UMR-S, Institut Universitaire d'Hématologie, Université Paris Diderot-Paris, France
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11
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Tomaiuolo M, Bertram R, Gonzalez-Iglesias AE, Tabak J. Investigating heterogeneity of intracellular calcium dynamics in anterior pituitary lactotrophs using a combined modelling/experimental approach. J Neuroendocrinol 2010; 22:1279-89. [PMID: 20738731 PMCID: PMC2988876 DOI: 10.1111/j.1365-2826.2010.02061.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cell responses are commonly heterogeneous, even within a subpopulation. In the present study, we investigate the source of heterogeneity in the Ca(2+) response of anterior pituitary lactotrophs to a Ca(2+) mobilisation agonist, thyrotrophin-releasing hormone. This response is characterised by a sharp increase of cytosolic Ca(2+) concentration as a result of mobilisation of Ca(2+) from intracellular stores, followed by a decrease to an elevated plateau level that results from Ca(2+) influx. We focus on heterogeneity of the evoked Ca(2+) spike under extracellular Ca(2+) free conditions. We introduce a method that uses the information provided by a mathematical model to characterise the source of heterogeneity. This method compares scatter plots of features of the Ca(2+) response obtained experimentally with those made from the mathematical model. The model scatter plots reflect random variation of parameters over different ranges, and matching the experimental and model scatter plots allows us to predict which parameters are most variable. We find that a large degree of variation in Ca(2+) efflux is a likely key contributor to the heterogeneity of Ca(2+) responses to thyrotrophin-releasing hormone in lactotrophs. This technique is applicable to any situation in which the heterogeneous biological response is described by a mathematical model.
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Affiliation(s)
- M Tomaiuolo
- Department of Biological Science and Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA.
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12
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Shaikh S, Samanta K, Kar P, Roy S, Chakraborti T, Chakraborti S. m-Calpain-mediated cleavage of Na+/Ca2+ exchanger-1 in caveolae vesicles isolated from pulmonary artery smooth muscle. Mol Cell Biochem 2010; 341:167-80. [PMID: 20372982 DOI: 10.1007/s11010-010-0448-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 03/17/2010] [Indexed: 01/30/2023]
Abstract
Using m-calpain antibody, we have identified two major bands corresponding to the 80 kDa large and the 28 kDa small subunit of m-calpain in caveolae vesicles isolated from bovine pulmonary artery smooth muscle plasma membrane. In addition, 78, 35, and 18 kDa immunoreactive bands of m-calpain have also been detected. Casein zymogram studies also revealed the presence of m-calpain in the caveolae vesicles. We have also identified Na(+)/Ca(2+) exchanger-1 (NCX1) in the caveolae vesicles. Purification and N-terminal sequence analyses of these two proteins confirmed their identities as m-calpain and NCX1, respectively. We further sought to determine the role of m-calpain on calcium-dependent proteolytic cleavage of NCX1 in the caveolae vesicles. Treatment of the caveolae vesicles with the calcium ionophore, A23187 (1 microM) in presence of CaCl(2) (1 mM) appears to cleave NCX1 (120 kDa) to an 82 kDa fragment as revealed by immunoblot study using NCX1 monoclonal antibody; while pretreatment with the calpain inhibitors, calpeptin or MDL28170; or the Ca(2+) chelator, BAPTA-AM did not cause a discernible change in the NCX protein profile. In vitro cleavage of the purified NCX1 by the purified m-calpain supports this finding. The cleavage of NCX1 by m-calpain in the caveolae vesicles may be interpreted as an important mechanism of Ca(2+) overload, which could arise due to inhibition of Ca(2+) efflux by the forward-mode NCX and that could lead to sustained Ca(2+) overload in the smooth muscle leading to pulmonary hypertension.
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Affiliation(s)
- Soni Shaikh
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, 741235 West Bengal, India
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13
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Samanta K, Kar P, Chakraborti T, Chakraborti S. Calcium-dependent cleavage of the Na(+)/Ca(2+) exchanger by m-calpain in isolated endoplasmic reticulum. J Biochem 2009; 147:225-35. [PMID: 19884190 DOI: 10.1093/jb/mvp176] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We have recently demonstrated the localization of associated m-calpain and calpastatin in the endoplasmic reticulum (ER) of bovine pulmonary artery smooth muscle. Herein, we sought to determine the role of m-calpain on calcium-dependent proteolytic cleavage of Na(+)/Ca(2+) exchanger (NCX) in the ER. Treatment of the ER with Ca(2+) (5 mM) dissociates m-calpain-calpastatin association leading to the activation of m-calpain, which subsequently cleaves the ER integral transmembrane protein NCX1 (116 kDa) to an 82 kDa fragment. Pre-treatment of the ER with calpain inhibitors, calpeptin (10 microM) or MDL28170 (10 microM), or Ca(2+) chelator, EGTA (10 mM) does not cleave NCX1. In vitro cleavage of the ER purified NCX1 by the ER purified m-calpain also supports our finding. Cleavage of NCX1 by m-calpain in the ER may be interpreted as the main cause of intracellular Ca(2+) overload in the smooth muscle, which could be important for the manifestation of pulmonary hypertension.
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Affiliation(s)
- Krishna Samanta
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India
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14
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Dellis O, Arbabian A, Brouland JP, Kovàcs T, Rowe M, Chomienne C, Joab I, Papp B. Modulation of B-cell endoplasmic reticulum calcium homeostasis by Epstein-Barr virus latent membrane protein-1. Mol Cancer 2009; 8:59. [PMID: 19650915 PMCID: PMC3098015 DOI: 10.1186/1476-4598-8-59] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 08/03/2009] [Indexed: 12/14/2022] Open
Abstract
Background Calcium signaling plays an important role in B lymphocyte survival and activation, and is critically dependent on the inositol-1,4,5-tris-phosphate-induced release of calcium stored in the endoplasmic reticulum (ER). Calcium is accumulated in the ER by Sarco/Endoplasmic Reticulum Calcium ATPases (SERCA enzymes), and therefore these enzymes play an important role in ER calcium homeostasis and in the control of B of cell activation. Because Epstein-Barr virus (EBV) can immortalize B cells and contributes to lymphomagenesis, in this work the effects of the virus on SERCA-type calcium pump expression and calcium accumulation in the endoplasmic reticulum of B cells was investigated. Results Two Sarco-Endoplasmic Reticulum Calcium transport ATPase isoforms, the low Ca2+-affinity SERCA3, and the high Ca2+-affinity SERCA2 enzymes are simultaneously expressed in B cells. Latency type III infection of Burkitt's lymphoma cell lines with immortalization-competent virus expressing the full set of latency genes selectively decreased the expression of SERCA3 protein, whereas infection with immortalization-deficient virus that does not express the EBNA2 or LMP-1 viral genes was without effect. Down-modulation of SERCA3 expression could be observed upon LMP-1, but not EBNA2 expression in cells carrying inducible transgenes, and LMP-1 expression was associated with enhanced resting cytosolic calcium levels and increased calcium storage in the endoplasmic reticulum. Similarly to virus-induced B cell immortalisation, SERCA3 expression was also decreased in normal B cells undergoing activation and blastic transformation in germinal centers of lymph node follicles. Conclusion The data presented in this work indicate that EBV-induced immortalization leads to the remodelling of ER calcium homeostasis of B cells by LMP-1 that copies a previously unknown normal phenomenon taking place during antigen driven B cell activation. The functional remodelling of ER calcium homeostasis by down-regulation of SERCA3 expression constitutes a previously unknown mechanism involved in EBV-induced B cell immortalisation.
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Affiliation(s)
- Olivier Dellis
- Institut National de la Santé et de la Recherche Médicale, Inserm UMR-S 940, Institut Universitaire d'Hématologie, Université Paris VII, Service d'Anatomie et Cytologie Pathologiques, Hôpital Lariboisière, 16, rue de la Grange aux Belles, 75010 Paris, France.
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Jahanshahi P, Wu R, Carter JD, Nunemaker CS. Evidence of diminished glucose stimulation and endoplasmic reticulum function in nonoscillatory pancreatic islets. Endocrinology 2009; 150:607-15. [PMID: 18818288 PMCID: PMC2646533 DOI: 10.1210/en.2008-0773] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Pulsatility is a fundamental feature of pancreatic islets and a hallmark of hormone secretion. Isolated pancreatic islets endogenously generate rhythms in secretion, metabolic activity, and intracellular calcium ([Ca(2+)](i)) that are important to normal physiological function. Few studies have directly compared oscillatory and nonoscillatory islets to identify possible differences in function. We investigated the hypothesis that the loss of these oscillations is a leading indicator of islet dysfunction by comparing oscillatory and nonoscillatory mouse islets for multiple parameters of function. Nonoscillatory islets displayed elevated basal [Ca(2+)](i) and diminished [Ca(2+)](i) response and insulin secretory response to 3-28 mm glucose stimulation compared with oscillatory islets, suggesting diminished glucose sensitivity. We investigated several possible mechanisms to explain these differences. No differences were observed in mitochondrial membrane potential, estimated ATP-sensitive potassium channel and L-type calcium channel activity, or cell death rates. Nonoscillatory islets, however, showed a reduced response to the sarco(endo)plasmic reticulum calcium ATPase inhibitor thapsigargin, suggesting a disruption in calcium homeostasis in the endoplasmic reticulum (ER) compared with oscillatory islets. The diminished ER calcium homeostasis among nonoscillatory islets was also consistent with the higher cytosolic calcium levels observed in 3 mm glucose. Inducing mild damage with low-dose proinflammatory cytokines reduced islet oscillatory capacity and produced similar effects on glucose-stimulated [Ca(2+)](i), basal [Ca(2+)](i), and thapsigargin response observed among untreated nonoscillatory islets. Our data suggest the loss of oscillatory capacity may be an early indicator of diminished islet glucose sensitivity and ER dysfunction, suggesting targets to improve islet assessment.
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Affiliation(s)
- Pooya Jahanshahi
- Department of Medicine, Division of Endocrinology and Metabolism, University of Virginia, Charlottesville, VA 22908-1413, USA
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