1
|
Xiang Y, Fan D, An Q, Zhang T, Wu X, Ding J, Xu X, Yue G, Tang S, Du Q, Xu J, Xie R. Effects of Ion-Transporting Proteins on the Digestive System Under Hypoxia. Front Physiol 2022; 13:870243. [PMID: 36187789 PMCID: PMC9515906 DOI: 10.3389/fphys.2022.870243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Hypoxia refers to a state of oxygen limitation, which mainly mediates pathological processes in the human body and participates in the regulation of normal physiological processes. In the hypoxic environment, the main regulator of human body homeostasis is the hypoxia-inducible factor family (HIF). HIF can regulate the expression of many hypoxia-induced genes and then participate in various physiological and pathological processes of the human body. Ion-transporting proteins are extremely important types of proteins. Ion-transporting proteins are distributed on cell membranes or organelles and strictly control the inflow or outflow of ions in cells or organelles. Changes in ions in cells are often closely related to extensive physiological and pathological processes in the human body. Numerous studies have confirmed that hypoxia and its regulatory factors can regulate the transcription and expression of ion-transporting protein-related genes. Under hypoxic stress, the regulation and interaction of ion-transporting proteins by hypoxia often leads to diseases of various human systems and even tumors. Using ion-transporting proteins and hypoxia as targets to explore the mechanism of digestive system diseases and targeted therapy is expected to become a new breakthrough point.
Collapse
Affiliation(s)
- Yiwei Xiang
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Dongdong Fan
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Qimin An
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Ting Zhang
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Xianli Wu
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Jianhong Ding
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Xiaolin Xu
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Gengyu Yue
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Siqi Tang
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Qian Du
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Jingyu Xu
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
- *Correspondence: Jingyu Xu, ; Rui Xie,
| | - Rui Xie
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
- *Correspondence: Jingyu Xu, ; Rui Xie,
| |
Collapse
|
2
|
Herchuelz A, Pachera N. The Na +/Ca 2+ exchanger and the Plasma Membrane Ca 2+-ATPase in β-cell function and diabetes. Neurosci Lett 2017; 663:72-78. [PMID: 28780165 DOI: 10.1016/j.neulet.2017.08.009] [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] [Received: 06/06/2017] [Revised: 07/17/2017] [Accepted: 08/01/2017] [Indexed: 12/20/2022]
Abstract
The rat pancreatic β-cell expresses 6 splice variants of the Plasma Membrane Ca2+-ATPase (PMCA) and two splice variants of the Na+/Ca2+ exchanger 1 (NCX1). In the β-cell Na+/Ca2+ exchange displays a high capacity, contributes to both Ca2+ outflow and influx and participates to the control of insulin release. Gain of function studies show that overexpression of PMCA2 or NCX1 leads to endoplasmic reticulum (ER) Ca2+ depletion with subsequent ER stress, decrease in β-cell proliferation and β-cell death by apoptosis. Loss of function studies show, on the contrary, that heterozygous inactivation of NCX1 (Ncx1+/-) leads to an increase in β-cell function and a 5 fold increase in both β-cell mass and proliferation. The mutation also increases β-cell resistance to hypoxia, and Ncx1+/- islets show a 2-4 times higher rate of diabetes cure than Ncx1+/+ islets when transplanted in diabetic animals. Thus, down-regulation of the Na+/Ca2+ exchanger leads to various changes in β-cell function that are opposite to the major abnormalities seen in diabetes. In addition, the β-cell includes the mutually exclusive exon B in the alternative splicing region of NCX1, which confers a high sensitivity of its NCX splice variants (NCX1.3 & 1.7) to the inhibitory action of compounds like KBR-7943. Heterozygous inactivation of PMCA2 leads to apparented, though not completely similar results.These provide 2 unique models for the prevention and treatment of β-cell dysfunction in diabetes and following islet transplantation.
Collapse
Affiliation(s)
- André Herchuelz
- Laboratoire de Pharmacodynamie et de Thérapeutique, Université Libre de Bruxelles (ULB), Faculté de Médicine, Brussels, Belgium.
| | - Nathalie Pachera
- Laboratoire de Pharmacodynamie et de Thérapeutique, Université Libre de Bruxelles (ULB), Faculté de Médicine, Brussels, Belgium
| |
Collapse
|
3
|
Pachera N, Papin J, Zummo FP, Rahier J, Mast J, Meyerovich K, Cardozo AK, Herchuelz A. Heterozygous inactivation of plasma membrane Ca(2+)-ATPase in mice increases glucose-induced insulin release and beta cell proliferation, mass and viability. Diabetologia 2015; 58:2843-50. [PMID: 26362865 DOI: 10.1007/s00125-015-3745-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 08/10/2015] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS Calcium plays an important role in the process of glucose-induced insulin release in pancreatic beta cells. These cells are equipped with a double system responsible for Ca(2+) extrusion--the Na/Ca exchanger (NCX) and the plasma membrane Ca(2+)-ATPase (PMCA). We have shown that heterozygous inactivation of NCX1 in mice increased glucose-induced insulin release and stimulated beta cell proliferation and mass. In the present study, we examined the effects of heterozygous inactivation of the PMCA on beta cell function. METHODS Biological and morphological methods (Ca(2+) imaging, Ca(2+) uptake, glucose metabolism, insulin release and immunohistochemistry) were used to assess beta cell function and proliferation in Pmca2 (also known as Atp2b2) heterozygous mice and control littermates ex vivo. Blood glucose and insulin levels were also measured to assess glucose metabolism in vivo. RESULTS Pmca (isoform 2) heterozygous inactivation increased intracellular Ca(2+) stores and glucose-induced insulin release. Moreover, increased beta cell proliferation, mass, viability and islet size were observed in Pmca2 heterozygous mice. However, no differences in beta cell glucose metabolism, proinsulin immunostaining and insulin content were observed. CONCLUSIONS/INTERPRETATION The present data indicates that inhibition of Ca(2+) extrusion from the beta cell and its subsequent intracellular accumulation stimulates beta cell function, proliferation and mass. This is in agreement with our previous results observed in mice displaying heterozygous inactivation of NCX, and indicates that inhibition of Ca(2+) extrusion mechanisms by small molecules in beta cells may represent a new approach in the treatment of type 1 and type 2 diabetes.
Collapse
Affiliation(s)
- Nathalie Pachera
- Laboratoire de Pharmacodynamie et de Thérapeutique, Bâtiment GE, Faculté de Médecine, Université Libre de Bruxelles (ULB), route de Lennik 808, B-1070, Bruxelles, Belgium
| | - Julien Papin
- Laboratoire de Pharmacodynamie et de Thérapeutique, Bâtiment GE, Faculté de Médecine, Université Libre de Bruxelles (ULB), route de Lennik 808, B-1070, Bruxelles, Belgium
| | - Francesco P Zummo
- Laboratoire de Pharmacodynamie et de Thérapeutique, Bâtiment GE, Faculté de Médecine, Université Libre de Bruxelles (ULB), route de Lennik 808, B-1070, Bruxelles, Belgium
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Jacques Rahier
- Department of Pathology, Faculty of Medicine, Université Catholique de Louvain, Brussels, Belgium
| | - Jan Mast
- Veterinary and Agrochemical Research Centre, VAR-CODA-CERVA, Brussels, Belgium
| | - Kira Meyerovich
- ULB Center for Diabetes Research, Faculté de Médecine, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Alessandra K Cardozo
- ULB Center for Diabetes Research, Faculté de Médecine, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - André Herchuelz
- Laboratoire de Pharmacodynamie et de Thérapeutique, Bâtiment GE, Faculté de Médecine, Université Libre de Bruxelles (ULB), route de Lennik 808, B-1070, Bruxelles, Belgium.
| |
Collapse
|
4
|
Sodium/calcium exchanger is upregulated by sulfide signaling, forms complex with the β1 and β3 but not β2 adrenergic receptors, and induces apoptosis. Pflugers Arch 2013; 466:1329-42. [PMID: 24114174 DOI: 10.1007/s00424-013-1366-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/06/2013] [Accepted: 09/20/2013] [Indexed: 10/26/2022]
Abstract
Hydrogen sulfide (H2S) as a novel gasotransmitter regulates variety of processes, including calcium transport systems. Sodium calcium exchanger (NCX) is one of the key players in a regulation calcium homeostasis. Thus, the aims of our work were to determine effect of sulfide signaling on the NCX type 1 (NCX1) expression and function in HeLa cells, to investigate the relationship of β-adrenergic receptors with the NCX1 in the presence and/or absence of H2S, and to determine physiological importance of this potential communication. As a H2S donor, we used morpholin-4-ium-4-methoxyphenyl(morpholino) phosphinodithioate-GYY4137. We observed increased levels of the NCX1 mRNA, protein, and activity after 24 h of GYY4137 treatment. This increase was accompanied by elevated cAMP due to the GYY4137 treatment, which was completely abolished, when NCX1 was silenced. Increased cAMP levels would point to upregulation of β-adrenergic receptors. Indeed, GYY4137 increased expression of β1 and β3 (but not β2) adrenergic receptors. These receptors co-precipitated, co-localized with the NCX1, and induced apoptosis in the presence of H2S. Our results suggest that sulfide signaling plays a role in regulation of the NCX1, β1 and β3 adrenergic receptors, their co-localization, and stimulation of apoptosis, which might be of a potential importance in cancer treatment.
Collapse
|
5
|
Mera T, Itoh T, Kita S, Kodama S, Kojima D, Nishinakamura H, Okamoto K, Ohkura M, Nakai J, Iyoda T, Iwamoto T, Matsuda T, Baba A, Omori K, Ono J, Watarai H, Taniguchi M, Yasunami Y. Pretreatment of donor islets with the Na(+) /Ca(2+) exchanger inhibitor improves the efficiency of islet transplantation. Am J Transplant 2013; 13:2154-60. [PMID: 23746308 DOI: 10.1111/ajt.12306] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/15/2013] [Accepted: 04/16/2013] [Indexed: 01/25/2023]
Abstract
Pancreatic islet transplantation is an attractive therapy for the treatment of insulin-dependent diabetes mellitus. However, the low efficiency of this procedure necessitating sequential transplantations of islets with the use of 2-3 donors for a single recipient, mainly due to the early loss of transplanted islets, hampers its clinical application. Previously, we have shown in mice that a large amount of HMGB1 is released from islets soon after their transplantation and that this triggers innate immune rejection with activation of DC, NKT cells and neutrophils to produce IFN-γ, ultimately leading to the early loss of transplanted islets. Thus, HMGB1 release plays an initial pivotal role in this process; however, its mechanism remains unclear. Here we demonstrate that release of HMGB1 from transplanted islets is due to hypoxic damage resulting from Ca(2+) influx into β cells through the Na(+) /Ca(2+) exchanger (NCX). Moreover, the hypoxia-induced β cell damage was prevented by pretreatment with an NCX-specific inhibitor prior to transplantation, resulting in protection and long-term survival of transplanted mouse and human islets when grafted into mice. These findings suggest a novel strategy with potentially great impact to improve the efficiency of islet transplantation in clinical settings by targeting donor islets rather than recipients.
Collapse
Affiliation(s)
- T Mera
- Central Research Institute for Islet Biology, Fukuoka University, Fukuoka, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Na(+)/Ca (2+) exchange and the plasma membrane Ca(2+)-ATPase in β-cell function and diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 961:385-94. [PMID: 23224897 DOI: 10.1007/978-1-4614-4756-6_33] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The rat pancreatic β-cell expresses two splice variants of the Na+/Ca(2+) exchanger 1 (NCX1) and six splice variants of the plasma membrane Ca(2+)-ATPase (PMCA). In the β-cell, Na(+)/Ca(2+) exchange displays a high capacity, contributes to both Ca(2+) outflow and influx and participates to the control of insulin release. Gain of function studies show that overexpression of NCX1 or PMCA2 leads to endoplasmic reticulum (ER) Ca(2+) depletion with subsequent ER stress, decrease in β-cell proliferation and β-cell death by apoptosis. Interestingly, chronic exposure to cytokines or high free fatty acids concentration also induces ER Ca(2+) depletion and β-cell death in diabetes. Loss of function studies shows, on the contrary, that heterozygous inactivation of NCX1 (Ncx1 ( +/- )) leads to an increase in β-cell function (insulin production and release) and a fivefold increase in both β-cell mass and proliferation. The mutation also increases β-cell resistance to hypoxia, and Ncx1 ( +/- ) islets show a four to seven times higher rate of diabetes cure than Ncx1 ( +/+ ) islets when transplanted in diabetic animals. Thus, downregulation of the Na(+)/Ca(2+) exchanger leads to various changes in β-cell function that are opposite to the major abnormalities seen in diabetes. In addition, the β-cell, which is an excitable cell, includes the mutually exclusive exon B in the alternative splicing region of NCX1, which confers a high sensitivity of its NCX splice variants (NCX1.3 & 1.7) to the inhibitory action of compounds like KB-R7943. This provides a unique model for the prevention and treatment of β-cell dysfunction in diabetes and following islet transplantation.
Collapse
|
7
|
Herchuelz A, Nguidjoe E, Jiang L, Pachera N. β-Cell preservation and regeneration in diabetes by modulation of β-cell Ca²⁺ homeostasis. Diabetes Obes Metab 2012; 14 Suppl 3:136-42. [PMID: 22928574 DOI: 10.1111/j.1463-1326.2012.01649.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ca(2+) extrusion from the β-cell is mediated by two processes the Na/Ca exchanger (NCX) and the plasma membrane Ca(2+) -ATPase (PMCA). Gain of function studies show that overexpression of NCX or PMCA leads to endoplasmic reticulum (ER) Ca(2+) depletion with subsequent ER stress, decrease in β-cell proliferation and β-cell death by apoptosis. Interestingly, chronic exposure to cytokines or high free fatty acid concentrations also induce ER Ca(2+) depletion and β-cell death in diabetes. Loss of function studies show, on the contrary, that heterozygous inactivation of NCX1 (Ncx1(+/-)) leads to an increase in β-cell function (insulin production and release), and a fivefold increase in both β-cell mass and proliferation. The mutation also increases β-cell resistance to hypoxia, and Ncx1(+/-) islets show a two to four times higher rate of diabetes cure than Ncx1(+/+) islets when transplanted in diabetic animals. Thus, down-regulation of the Na/Ca exchanger leads to various changes in β-cell function that are opposite to the major abnormalities seen in diabetes. This provides a unique model for the prevention and treatment of β-cell dysfunction in diabetes and following islet transplantation.
Collapse
Affiliation(s)
- A Herchuelz
- Laboratoire de Pharmacodynamie et de Thérapeutique, Université Libre de Bruxelles, Faculté de Médicine, B-1070, Brussels, Belgium.
| | | | | | | |
Collapse
|
8
|
Nguidjoe E, Sokolow S, Bigabwa S, Pachera N, D'Amico E, Allagnat F, Vanderwinden JM, Sener A, Manto M, Depreter M, Mast J, Joanny G, Montanya E, Rahier J, Cardozo AK, Eizirik DL, Schurmans S, Herchuelz A. Heterozygous inactivation of the Na/Ca exchanger increases glucose-induced insulin release, β-cell proliferation, and mass. Diabetes 2011; 60:2076-85. [PMID: 21659499 PMCID: PMC3142081 DOI: 10.2337/db10-0924] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE We have previously shown that overexpression of the Na-Ca exchanger (NCX1), a protein responsible for Ca(2+) extrusion from cells, increases β-cell programmed cell death (apoptosis) and reduces β-cell proliferation. To further characterize the role of NCX1 in β-cells under in vivo conditions, we developed and characterized mice deficient for NCX1. RESEARCH DESIGN AND METHODS Biologic and morphologic methods (Ca(2+) imaging, Ca(2+) uptake, glucose metabolism, insulin release, and point counting morphometry) were used to assess β-cell function in vitro. Blood glucose and insulin levels were measured to assess glucose metabolism and insulin sensitivity in vivo. Islets were transplanted under the kidney capsule to assess their performance to revert diabetes in alloxan-diabetic mice. RESULTS Heterozygous inactivation of Ncx1 in mice induced an increase in glucose-induced insulin release, with a major enhancement of its first and second phase. This was paralleled by an increase in β-cell proliferation and mass. The mutation also increased β-cell insulin content, proinsulin immunostaining, glucose-induced Ca(2+) uptake, and β-cell resistance to hypoxia. In addition, Ncx1(+/-) islets showed a two- to four-times higher rate of diabetes cure than Ncx1(+/+) islets when transplanted into diabetic animals. CONCLUSIONS Downregulation of the Na/Ca exchanger leads to an increase in β-cell function, proliferation, mass, and resistance to physiologic stress, namely to various changes in β-cell function that are opposite to the major abnormalities seen in type 2 diabetes. This provides a unique model for the prevention and treatment of β-cell dysfunction in type 2 diabetes and after islet transplantation.
Collapse
Affiliation(s)
- Evrard Nguidjoe
- Laboratory of Pharmacology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Sophie Sokolow
- Laboratory of Pharmacology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
- Laboratory of Experimental Medicine, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Serge Bigabwa
- Laboratory of Pharmacology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Nathalie Pachera
- Laboratory of Pharmacology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Eva D'Amico
- Laboratory of Experimental Medicine, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Florent Allagnat
- Laboratory of Neurophysiology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Jean-Marie Vanderwinden
- Laboratory of Experimental Hormonology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Abdullah Sener
- Institute of Interdisciplinary Research, Institute of Molecular Biology and Medicine (IRIBHM-IBMM), Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Mario Manto
- Laboratory of Experimental Neurology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Marianne Depreter
- Veterinary and Agrochemical Research Centre, VAR-CODA-CERVA, Brussels, Belgium
| | - Jan Mast
- Veterinary and Agrochemical Research Centre, VAR-CODA-CERVA, Brussels, Belgium
| | - Geraldine Joanny
- Laboratory of Diabetes and Experimental Endocrinology, Institut d'Investigació Biomèdica de Bellvitge–University of Barcelona, Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabolicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Eduard Montanya
- Laboratory of Diabetes and Experimental Endocrinology, Institut d'Investigació Biomèdica de Bellvitge–University of Barcelona, Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabolicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Jacques Rahier
- Department of Pathology, Faculty of Medicine, Université Catholique de Louvain, Brussels, Belgium
| | - Alessandra K. Cardozo
- Laboratory of Neurophysiology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Décio L. Eizirik
- Laboratory of Neurophysiology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Stéphane Schurmans
- Laboratory of Experimental Medicine, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - André Herchuelz
- Laboratory of Pharmacology, Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
- Corresponding author: André Herchuelz,
| |
Collapse
|
9
|
Lei X, Zhang S, Emani B, Barbour SE, Ramanadham S. A link between endoplasmic reticulum stress-induced β-cell apoptosis and the group VIA Ca2+-independent phospholipase A2 (iPLA2β). Diabetes Obes Metab 2010; 12 Suppl 2:93-8. [PMID: 21029305 PMCID: PMC3713613 DOI: 10.1111/j.1463-1326.2010.01270.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Endoplasmic reticulum (ER) stress is becoming recognized as an important contributing factor in various diseases, including diabetes mellitus. Prolonged ER stress can cause β-cell apoptosis; however, the underlying mechanism(s) that contribute to this process are not well understood. Early reports suggested that arachidonic acid metabolites and a Ca(2+)-independent phospholipase A(2) (iPLA(2)) activity play a role in β-cell apoptosis. The PLA(2) family of enzymes catalyse the hydrolysis of the sn-2 substituent (i.e. arachidonic acid) of membrane phospholipids. In light of our findings that the pancreatic islet β-cells are enriched in arachidonate-containing phospholipids and express the group VIA iPLA(2)β, we considered the possibility that iPLA(2)β participates in ER stress-induced β-cell apoptosis. Our work revealed a novel mechanism, involving ceramide generation and triggering of mitochondrial abnormalities, by which iPLA(2)β participates in the β-cell apoptosis process. Here, we review our evidence linking ER stress, β-cell apoptosis and iPLA(2)β. Continued studies in this area will increase our understanding of the contribution of iPLA(2)β to the evolution of diabetes mellitus and will further our knowledge of factors that influence β-cell health in diabetes mellitus and identify potential targets for future therapeutic interventions to prevent β-cell death.
Collapse
Affiliation(s)
- X Lei
- Department of Medicine, Mass Spectrometry Resource and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St Louis, MO 63110, USA
| | | | | | | | | |
Collapse
|
10
|
Balan AG, Myers BJ, Maganti JL, Moore DB. ER-targeted Bcl-2 and inhibition of ER-associated caspase-12 rescue cultured immortalized cells from ethanol toxicity. Alcohol 2010; 44:553-63. [PMID: 20727705 DOI: 10.1016/j.alcohol.2010.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 06/24/2010] [Accepted: 07/01/2010] [Indexed: 12/13/2022]
Abstract
Alcohol abuse, known for promoting apoptosis in the liver and nervous system, is a major public health concern. Despite significant morbidity and mortality resulting from ethanol consumption, the precise cellular mechanism of its toxicity remains unknown. Previous work has shown that wild-type Bcl-2 is protective against ethanol. The present study investigated whether protection from ethanol toxicity involves mitochondrial Bcl-2 or endoplasmic reticulum (ER) Bcl-2, and whether mitochondria-associated or ER-associated caspases are involved in ethanol toxicity. Chinese hamster ovary (CHO695) cells were transiently transfected with cDNA constructs encoding wild-type Bcl-2, mitochondria-targeted Bcl-2, or ER-targeted Bcl-2. MTT assay was used to measure cell viability in response to ethanol. Ethanol treatments of 1 and 2.5 M reduced cell viability at 5, 10, and 24 h. Wild-type Bcl-2, localized both to mitochondria and ER, provided significant rescue for CHO695 cells treated with 1M ethanol for 24 h, but did not rescue toxicity at 2.5 M. ER-targeted Bcl-2, however, provided significant and robust rescue following 24 h of 1 and 2.5 M ethanol. Mitochondria-targeted Bcl-2 offered no protection at any ethanol concentration and generally reduced cell viability. To follow up these experiments, we used a peptide inhibitor approach to investigate which caspases were responsible for ethanol-induced apoptosis. Caspase-9 and caspase-12 are known to be downstream of mitochondria and the ER, respectively. CHO695 cells were treated with a pan-caspase inhibitor, a caspase-9 or caspase-12 inhibitor along with 1.5 M ethanol, followed by MTT cell viability assay. Treatment with the pan-caspase inhibitor provided significant rescue from ethanol, whereas inhibition of caspase-9 did not. Inhibition of ER-associated caspase-12, however, conferred significant protection from ethanol toxicity, similar to the pan inhibitor. These findings are consistent with our transfection data and, taken together, suggest a significant role for the ER in ethanol toxicity.
Collapse
Affiliation(s)
- Andreea G Balan
- Department of Biology, Kalamazoo College, Kalamazoo, MI, USA
| | | | | | | |
Collapse
|
11
|
Jiang L, Allagnat F, Nguidjoe E, Kamagate A, Pachera N, Vanderwinden JM, Brini M, Carafoli E, Eizirik DL, Cardozo AK, Herchuelz A. Plasma membrane Ca2+-ATPase overexpression depletes both mitochondrial and endoplasmic reticulum Ca2+ stores and triggers apoptosis in insulin-secreting BRIN-BD11 cells. J Biol Chem 2010; 285:30634-43. [PMID: 20660595 DOI: 10.1074/jbc.m110.116681] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ca(2+) may trigger apoptosis in β-cells. Hence, the control of intracellular Ca(2+) may represent a potential approach to prevent β-cell apoptosis in diabetes. Our objective was to investigate the effect and mechanism of action of plasma membrane Ca(2+)-ATPase (PMCA) overexpression on Ca(2+)-regulated apoptosis in clonal β-cells. Clonal β-cells (BRIN-BD11) were examined for the effect of PMCA overexpression on cytosolic and mitochondrial [Ca(2+)] using a combination of aequorins with different Ca(2+) affinities and on the ER and mitochondrial pathways of apoptosis. β-cell stimulation generated microdomains of high [Ca(2+)] in the cytosol and subcellular heterogeneities in [Ca(2+)] among mitochondria. Overexpression of PMCA decreased [Ca(2+)] in the cytosol, the ER, and the mitochondria and activated the IRE1α-XBP1s but inhibited the PRKR-like ER kinase-eIF2α and the ATF6-BiP pathways of the ER-unfolded protein response. Increased Bax/Bcl-2 expression ratio was observed in PMCA overexpressing β-cells. This was followed by Bax translocation to the mitochondria with subsequent cytochrome c release, opening of the permeability transition pore, and apoptosis. In conclusion, clonal β-cell stimulation generates microdomains of high [Ca(2+)] in the cytosol and subcellular heterogeneities in [Ca(2+)] among mitochondria. PMCA overexpression depletes intracellular [Ca(2+)] stores and, despite a decrease in mitochondrial [Ca(2+)], induces apoptosis through the mitochondrial pathway. These data open the way to new strategies to control cellular Ca(2+) homeostasis that could decrease β-cell apoptosis in diabetes.
Collapse
Affiliation(s)
- Lin Jiang
- Laboratoire de Pharmacodynamie et de Thérapeutique, Université Libre de Bruxelles, Faculté deMédecine, Bâtiment GE, 808 route de Lennik, B-1070 Brussels, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Lei X, Zhang S, Barbour SE, Bohrer A, Ford EL, Koizumi A, Papa FR, Ramanadham S. Spontaneous development of endoplasmic reticulum stress that can lead to diabetes mellitus is associated with higher calcium-independent phospholipase A2 expression: a role for regulation by SREBP-1. J Biol Chem 2010; 285:6693-705. [PMID: 20032468 PMCID: PMC2825464 DOI: 10.1074/jbc.m109.084293] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 12/18/2009] [Indexed: 01/09/2023] Open
Abstract
Our recent studies indicate that endoplasmic reticulum (ER) stress causes INS-1 cell apoptosis by a Ca(2+)-independent phospholipase A(2) (iPLA(2)beta)-mediated mechanism that promotes ceramide generation via sphingomyelin hydrolysis and subsequent activation of the intrinsic pathway. To elucidate the association between iPLA(2)beta and ER stress, we compared beta-cell lines generated from wild type (WT) and Akita mice. The Akita mouse is a spontaneous model of ER stress that develops hyperglycemia/diabetes due to ER stress-induced beta-cell apoptosis. Consistent with a predisposition to developing ER stress, basal phosphorylated PERK and activated caspase-3 are higher in the Akita cells than WT cells. Interestingly, basal iPLA(2)beta, mature SREBP-1 (mSREBP-1), phosphorylated Akt, and neutral sphingomyelinase (NSMase) are higher, relative abundances of sphingomyelins are lower, and mitochondrial membrane potential (DeltaPsi) is compromised in Akita cells, in comparison with WT cells. Exposure to thapsigargin accelerates DeltaPsi loss and apoptosis of Akita cells and is associated with increases in iPLA(2)beta, mSREBP-1, and NSMase in both WT and Akita cells. Transfection of Akita cells with iPLA(2)beta small interfering RNA, however, suppresses NSMase message, DeltaPsi loss, and apoptosis. The iPLA(2)beta gene contains a sterol-regulatory element, and transfection with a dominant negative SREBP-1 reduces basal mSREBP-1 and iPLA(2)beta in the Akita cells and suppresses increases in mSREBP-1 and iPLA(2)beta due to thapsigargin. These findings suggest that ER stress leads to generation of mSREBP-1, which can bind to the sterol-regulatory element in the iPLA(2)beta gene to promote its transcription. Consistent with this, SREBP-1, iPLA(2)beta, and NSMase messages in Akita mouse islets are higher than in WT islets.
Collapse
Affiliation(s)
- Xiaoyong Lei
- From the Department of Medicine, Mass Spectrometry Resource, and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Sheng Zhang
- From the Department of Medicine, Mass Spectrometry Resource, and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Suzanne E. Barbour
- the Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298
| | - Alan Bohrer
- From the Department of Medicine, Mass Spectrometry Resource, and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Eric L. Ford
- From the Department of Medicine, Mass Spectrometry Resource, and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Akio Koizumi
- the Department of Health and Environmental Sciences, Kyoto Graduate School of Medicine, Kyoto 606-8501, Japan, and
| | - Feroz R. Papa
- the California Institute for Quantitative Biosciences, University of California, San Francisco, California 94143
| | - Sasanka Ramanadham
- From the Department of Medicine, Mass Spectrometry Resource, and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri 63110
| |
Collapse
|
13
|
Lei X, Barbour SE, Ramanadham S. Group VIA Ca2+-independent phospholipase A2 (iPLA2beta) and its role in beta-cell programmed cell death. Biochimie 2010; 92:627-37. [PMID: 20083151 DOI: 10.1016/j.biochi.2010.01.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 01/11/2010] [Indexed: 01/09/2023]
Abstract
Activation of phospholipases A(2) (PLA(2)s) leads to the generation of biologically active lipid mediators that can affect numerous cellular events. The Group VIA Ca(2+)-independent PLA(2), designated iPLA(2)beta, is active in the absence of Ca(2+), activated by ATP, and inhibited by the bromoenol lactone suicide inhibitor (BEL). Over the past 10-15 years, studies using BEL have demonstrated that iPLA(2)beta participates in various biological processes and the recent availability of mice in which iPLA(2)beta expression levels have been genetically-modified are extending these findings. Work in our laboratory suggests that iPLA(2)beta activates a unique signaling cascade that promotes beta-cell apoptosis. This pathway involves iPLA(2)beta dependent induction of neutral sphingomyelinase, production of ceramide, and activation of the intrinsic pathway of apoptosis. There is a growing body of literature supporting beta-cell apoptosis as a major contributor to the loss of beta-cell mass associated with the onset and progression of Type 1 and Type 2 diabetes mellitus. This underscores a need to gain a better understanding of the molecular mechanisms underlying beta-cell apoptosis so that improved treatments can be developed to prevent or delay the onset and progression of diabetes mellitus. Herein, we offer a general review of Group VIA Ca(2+)-independent PLA(2) (iPLA(2)beta) followed by a more focused discussion of its participation in beta-cell apoptosis. We suggest that iPLA(2)beta-derived products trigger pathways which can lead to beta-cell apoptosis during the development of diabetes.
Collapse
Affiliation(s)
- Xiaoyong Lei
- Department of Medicine, Mass Spectrometry Resource and Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | | |
Collapse
|
14
|
Prothymosin α and cell death mode switch, a novel target for the prevention of cerebral ischemia-induced damage. Pharmacol Ther 2009; 123:323-33. [DOI: 10.1016/j.pharmthera.2009.05.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Accepted: 05/11/2009] [Indexed: 12/17/2022]
|
15
|
Wang Q, Zhang H, Zhao B, Fei H. IL-1beta caused pancreatic beta-cells apoptosis is mediated in part by endoplasmic reticulum stress via the induction of endoplasmic reticulum Ca2+ release through the c-Jun N-terminal kinase pathway. Mol Cell Biochem 2008; 324:183-90. [PMID: 19109696 DOI: 10.1007/s11010-008-9997-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Accepted: 12/11/2008] [Indexed: 10/21/2022]
Abstract
Endoplasmic reticulum (ER) homeostasis is crucial for beta-cell function and survival. Direct as well as indirect evidence has pointed toward Ca(2+) as an important determinant of interleukin-1beta (IL-1beta)-induced beta-cell dysfunction and apoptosis. In the present study, we show that IL-1beta-induced apoptosis and necrosis in primary rat beta-cells and MIN6 cells largely depends on ER stress, ER Ca(2+) release, and c-Jun N-terminal kinase (JNK) activation. beta-cells also showed marked sensitivity to apoptosis induced by sarcoendoplasmic reticulum Ca(2+) ATPase (SERCA) blockers, thapsigargin and cyclopiazonic acid (CPA). IL-1beta induced ER Ca(2+) release, which was paralleled by an IL-1beta-dependent induction of JNK activation and the ER stress response, including activation of PRK (RNA-dependent protein kinase)-like ER kinase (PERK). Furthermore, reduced activation of JNK, utilizing JNK inhibitor SP600125, resulted in significant protection from IL-1beta- or thapsigargin-induced apoptosis via ER stress. In conclusion, our results suggest that the IL-1beta-induced depletion of ER Ca(2+) and activation of the ER stress via JNK pathway are potential contributory mechanisms to beta-cell death.
Collapse
Affiliation(s)
- Q Wang
- Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Ministry of Education, Shanghai Jiaotong University, Shanghai, People's Republic of China.
| | | | | | | |
Collapse
|
16
|
Lei X, Zhang S, Bohrer A, Ramanadham S. Calcium-independent phospholipase A2 (iPLA2 beta)-mediated ceramide generation plays a key role in the cross-talk between the endoplasmic reticulum (ER) and mitochondria during ER stress-induced insulin-secreting cell apoptosis. J Biol Chem 2008; 283:34819-32. [PMID: 18936091 PMCID: PMC2596401 DOI: 10.1074/jbc.m807409200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 10/15/2008] [Indexed: 01/09/2023] Open
Abstract
Endoplasmic reticulum (ER) stress induces INS-1 cell apoptosis by a pathway involving Ca(2+)-independent phospholipase A(2) (iPLA(2)beta)-mediated ceramide generation, but the mechanism by which iPLA(2)beta and ceramides contribute to apoptosis is not well understood. We report here that both caspase-12 and caspase-3 are activated in INS-1 cells following induction of ER stress with thapsigargin, but only caspase-3 cleavage is amplified in iPLA(2)beta overexpressing INS-1 cells (OE), relative to empty vector-transfected cells, and is suppressed by iPLA(2)beta inhibition. ER stress also led to the release of cytochrome c and Smac and, unexpectedly, their accumulation in the cytosol is amplified in OE cells. These findings raise the likelihood that iPLA(2)beta participates in ER stress-induced apoptosis by activating the intrinsic apoptotic pathway. Consistent with this possibility, we find that ER stress promotes iPLA(2)beta accumulation in the mitochondria, opening of mitochondrial permeability transition pore, and loss in mitochondrial membrane potential (Delta Psi) in INS-1 cells and that these changes are amplified in OE cells. ER stress also led to greater ceramide generation in ER and mitochondria fractions of OE cells. Exposure to ceramide alone induces loss in Delta Psi and apoptosis and these are suppressed by forskolin. ER stress-induced mitochondrial dysfunction and apoptosis are also inhibited by forskolin, as well as by inactivation of iPLA(2)beta or NSMase, suggesting that iPLA(2)beta-mediated generation of ceramides via sphingomyelin hydrolysis during ER stress affect the mitochondria. In support, inhibition of iPLA(2)beta or NSMase prevents cytochrome c release. Collectively, our findings indicate that the iPLA(2)beta-ceramide axis plays a critical role in activating the mitochondrial apoptotic pathway in insulin-secreting cells during ER stress.
Collapse
Affiliation(s)
| | | | | | - Sasanka Ramanadham
- Department of Medicine, Mass Spectrometry Resource and Division of
Endocrinology, Metabolism, and Lipid Research, Washington University School of
Medicine, St. Louis, Missouri 63110
| |
Collapse
|
17
|
Cunha DA, Hekerman P, Ladrière L, Bazarra-Castro A, Ortis F, Wakeham MC, Moore F, Rasschaert J, Cardozo AK, Bellomo E, Overbergh L, Mathieu C, Lupi R, Hai T, Herchuelz A, Marchetti P, Rutter GA, Eizirik DL, Cnop M. Initiation and execution of lipotoxic ER stress in pancreatic beta-cells. J Cell Sci 2008; 121:2308-18. [PMID: 18559892 PMCID: PMC3675788 DOI: 10.1242/jcs.026062] [Citation(s) in RCA: 466] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Free fatty acids (FFA) cause apoptosis of pancreatic beta-cells and might contribute to beta-cell loss in type 2 diabetes via the induction of endoplasmic reticulum (ER) stress. We studied here the molecular mechanisms implicated in FFA-induced ER stress initiation and apoptosis in INS-1E cells, FACS-purified primary beta-cells and human islets exposed to oleate and/or palmitate. Treatment with saturated and/or unsaturated FFA led to differential ER stress signaling. Palmitate induced more apoptosis and markedly activated the IRE1, PERK and ATF6 pathways, owing to a sustained depletion of ER Ca(2+) stores, whereas the unsaturated FFA oleate led to milder PERK and IRE1 activation and comparable ATF6 signaling. Non-metabolizable methyl-FFA analogs induced neither ER stress nor beta-cell apoptosis. The FFA-induced ER stress response was not modified by high glucose concentrations, suggesting that ER stress in primary beta-cells is primarily lipotoxic, and not glucolipotoxic. Palmitate, but not oleate, activated JNK. JNK inhibitors reduced palmitate-mediated AP-1 activation and apoptosis. Blocking the transcription factor CHOP delayed palmitate-induced beta-cell apoptosis. In conclusion, saturated FFA induce ER stress via ER Ca(2+) depletion. The IRE1 and resulting JNK activation contribute to beta-cell apoptosis. PERK activation by palmitate also contributes to beta-cell apoptosis via CHOP.
Collapse
Affiliation(s)
- Daniel A. Cunha
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Paul Hekerman
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Laurence Ladrière
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Angie Bazarra-Castro
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Fernanda Ortis
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Marion C. Wakeham
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Fabrice Moore
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Joanne Rasschaert
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Alessandra K. Cardozo
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Elisa Bellomo
- Department of Cell Biology, Division of Medicine, Faculty of Medicine, Imperial College London, London, UK
| | - Lutgart Overbergh
- Laboratory for Experimental Medicine and Endocrinology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium
| | - Chantal Mathieu
- Laboratory for Experimental Medicine and Endocrinology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium
| | - Roberto Lupi
- Department of Endocrinology and Metabolism, Metabolic Unit, University of Pisa, Pisa, Italy
| | - Tsonwin Hai
- Department of Molecular and Cellular Biochemistry and Center for Molecular Neurobiology, Ohio State University, Columbus, OH, USA
| | - Andre Herchuelz
- Laboratory of Pharmacology, Université Libre de Bruxelles, Brussels, Belgium
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, Metabolic Unit, University of Pisa, Pisa, Italy
| | - Guy A. Rutter
- Department of Cell Biology, Division of Medicine, Faculty of Medicine, Imperial College London, London, UK
| | - Décio L. Eizirik
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
| | - Miriam Cnop
- Laboratory of Experimental Medicine, Université Libre de Bruxelles CP-618, Route de Lennik 808, 1070 Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Brussels, Belgium
| |
Collapse
|
18
|
Mizobuchi M, Ogata H, Hatamura I, Saji F, Koiwa F, Kinugasa E, Koshikawa S, Akizawa T. Activation of calcium-sensing receptor accelerates apoptosis in hyperplastic parathyroid cells. Biochem Biophys Res Commun 2007; 362:11-16. [PMID: 17706605 DOI: 10.1016/j.bbrc.2007.07.177] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Accepted: 07/10/2007] [Indexed: 11/19/2022]
Abstract
Calcimimetic compounds inhibit not only parathyroid hormone (PTH) synthesis and secretion, but also parathyroid cell proliferation. The aim of this investigation is to examine the effect of the calcimimetic compound NPS R-568 (R-568) on parathyroid cell death in uremic rats. Hyperplastic parathyroid glands were obtained from uremic rats (subtotal nephrectomy and high-phosphorus diet), and incubated in the media only or the media which contained high concentration of R-568 (10(-4)M), or 10% cyclodextrin, for 6h. R-568 treatment significantly suppressed medium PTH concentration compared with that of the other two groups. R-568 treatment not only increased the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay-positive cells, but also induced the morphologic changes of cell death determined by light or electron microscopy. These results suggest that CaR activation by R-568 accelerates parathyroid cell death, probably through an apoptotic mechanism in uremic rats in vitro.
Collapse
Affiliation(s)
- Masahide Mizobuchi
- Department of Nephrology, School of Medicine, Showa University, Tokyo, Japan
| | - Hiroaki Ogata
- Department of Internal Medicine, Showa University Northern Yokohama Hospital, 35-1, Chigasaki-chuo, Tsuzuki, Yokohama 224-8503, Japan.
| | - Ikuji Hatamura
- First Department of Pathology, Wakayama Medical University, Wakayama, Japan
| | - Fumie Saji
- Division of Nephrology and Blood Purification Medicine, Wakayama Medical University, Wakayama, Japan
| | - Fumihiko Koiwa
- Division of Nephrology, Department of Internal Medicine, Showa University Fujigaoka Hospital, Yokohama, Japan
| | - Eriko Kinugasa
- Department of Internal Medicine, Showa University Northern Yokohama Hospital, 35-1, Chigasaki-chuo, Tsuzuki, Yokohama 224-8503, Japan
| | - Shozo Koshikawa
- Division of Nephrology, Department of Internal Medicine, Showa University Fujigaoka Hospital, Yokohama, Japan
| | - Tadao Akizawa
- Department of Nephrology, School of Medicine, Showa University, Tokyo, Japan
| |
Collapse
|
19
|
Lei XY, Zhang S, Bohrer A, Bao S, Song H, Ramanadham S. The group VIA calcium-independent phospholipase A2 participates in ER stress-induced INS-1 insulinoma cell apoptosis by promoting ceramide generation via hydrolysis of sphingomyelins by neutral sphingomyelinase. Biochemistry 2007; 46:10170-85. [PMID: 17685585 PMCID: PMC2530898 DOI: 10.1021/bi700017z] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Beta-cell mass is regulated by a balance between beta-cell growth and beta-cell death, due to apoptosis. We previously reported that apoptosis of INS-1 insulinoma cells due to thapsigargin-induced ER stress was suppressed by inhibition of the group VIA Ca2+-independent phospholipase A2 (iPLA2beta), associated with an increased level of ceramide generation, and that the effects of ER stress were amplified in INS-1 cells in which iPLA2beta was overexpressed (OE INS-1 cells). These findings suggested that iPLA2beta and ceramides participate in ER stress-induced INS-1 cell apoptosis. Here, we address this possibility and also the source of the ceramides by examining the effects of ER stress in empty vector (V)-transfected and iPLA2beta-OE INS-1 cells using apoptosis assays and immunoblotting, quantitative PCR, and mass spectrometry analyses. ER stress induced expression of ER stress factors GRP78 and CHOP, cleavage of apoptotic factor PARP, and apoptosis in V and OE INS-1 cells. Accumulation of ceramide during ER stress was not associated with changes in mRNA levels of serine palmitoyltransferase (SPT), the rate-limiting enzyme in de novo synthesis of ceramides, but both message and protein levels of neutral sphingomyelinase (NSMase), which hydrolyzes sphingomyelins to generate ceramides, were temporally increased in the INS-1 cells. The increases in the level of NSMase expression in the ER-stressed INS-1 cells were associated with corresponding temporal elevations in ER-associated iPLA2beta protein and catalytic activity. Pretreatment with BEL inactivated iPLA2beta and prevented induction of NSMase message and protein in ER-stressed INS-1 cells. Relative to that in V INS-1 cells, the effects of ER stress were accelerated and/or amplified in the OE INS-1 cells. However, inhibition of iPLA2beta or NSMase (chemically or with siRNA) suppressed induction of NSMase message, ceramide generation, sphingomyelin hydrolysis, and apoptosis in both V and OE INS-1 cells during ER stress. In contrast, inhibition of SPT did not suppress ceramide generation or apoptosis in either V or OE INS-1 cells. These findings indicate that iPLA2beta activation participates in ER stress-induced INS-1 cell apoptosis by promoting ceramide generation via NSMase-catalyzed hydrolysis of sphingomyelins, raising the possibility that this pathway contributes to beta-cell apoptosis due to ER stress.
Collapse
Affiliation(s)
| | | | | | | | | | - Sasanka Ramanadham
- *Address correspondence to: Sasanka Ramanadham, Dept. Medicine, Washington University School of Medicine, Campus Box 8127, 660 S. Euclid Ave., St. Louis, MO 63110; telephone 314-362-8194; FAX 314-362-7641; E-mail:
| |
Collapse
|
20
|
Herchuelz A, Kamagate A, Ximenes H, Van Eylen F. Role of Na/Ca exchange and the plasma membrane Ca2+-ATPase in beta cell function and death. Ann N Y Acad Sci 2007; 1099:456-67. [PMID: 17446486 DOI: 10.1196/annals.1387.048] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Recent progresses concerning the Na/Ca exchanger (NCX) and the plasma membrane Ca2+-ATPase (PMCA) in the pancreatic beta cell are reviewed. The rat beta cell expresses two splice variants of NCX1 and six splice variants of the 4 PMCA isoforms. At the protein level, the most abundant forms are PMCA2 and PMCA3, providing the first evidence for the presence of these two isoforms in a non-neuronal tissue. Overexpression of NCX1 in an insulinoma cell line altered the initial rise in cytosolic-free Ca2+ concentration ([Ca2+]i) induced by membrane depolarization and the return of the [Ca2+]i to the baseline value on membrane repolarization, indicating that NCX contributes to both Ca2+ inflow and outflow in the beta cell. In contrast, overexpression of the PMCA markedly reduced the global rise in Ca2+ induced by membrane depolarization, indicating that the PMCA has a capacity higher than expected to extrude Ca2+. Glucose, the main physiological stimulus of insulin release from the beta cell, has opposite effect on NCX and PMCA transcription, expression and activity, inducing an increase in the case of NCX and a decrease in the case of the PMCA. This indicates that when exposed to glucose, the beta cell switches from a low-efficiency Ca2+ extruding mechanism, the PMCA, to a high-capacity system, the NCX, in order to better face the increase in Ca2+ inflow induced by the sugar. To our knowledge, this is the first demonstration of a reciprocal change in PMCA and NCX1 expression and activity in response to a given stimulus in any tissue.
Collapse
Affiliation(s)
- André Herchuelz
- Laboratory of Pharmacology, Brussels University School of Medicine, B-1070, Brussels, Belgium.
| | | | | | | |
Collapse
|
21
|
Lee SH, Park KH, Ho WK, Lee SH. Postnatal developmental changes in Ca2+ homeostasis in supraoptic magnocellular neurons. Cell Calcium 2007; 41:441-50. [PMID: 17010427 DOI: 10.1016/j.ceca.2006.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 08/10/2006] [Accepted: 08/24/2006] [Indexed: 11/16/2022]
Abstract
Supraoptic magnocellular neurons (SMNs) undergo dramatic changes in morphological and electrical properties during postnatal development. We investigated the developmental change in Ca2+ homeostasis in SMNs. The decay rate of Ca2+ transients markedly increased during the third postnatal week (PW3) to an adult level. This increase in the Ca2+ decay rate was paralleled by hypertrophy of the SMN somata. Activity of Na+/Ca2+ exchanger (Na/CaX) and sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) was quantified as a decrement in the Ca2+ decay rate caused by extracellular [Na+] reduction and that by thapsigargin, respectively. SERCA activity was negligible during PW2, and markedly increased during PW3. SERCA activity and soma size remained stable thereafter. Na/CaX activity was a major Ca2+-clearance mechanism (CCM) during PW2, increased further during PW3, but was negligible in mature SMNs (PW10). In parallel with the decrease in Na/CaX activity, endogenous Ca2+ buffering capacity declined, resulting that the apparent Ca2+ decay rate remained relatively constant between PW4 and PW10. Replacement of intracellular K+ with Li+ had no effect on Na/CaX activity, suggesting that NCX rather than NCKX comprises Na/CaX. These findings indicate a developmental shift in the balance of CCMs from Ca2+ extrusion via NCX toward Ca2+ sequestration into endoplasmic reticulum via SERCA.
Collapse
Affiliation(s)
- Sang Hun Lee
- National Research Laboratory for Cell Physiology, Department of Physiology, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Ku, Seoul 110-799, South Korea
| | | | | | | |
Collapse
|
22
|
Nguidjoe E, Herchuelz A. Overexpression of Na/Ca exchanger reduces viability and proliferation of gliosarcoma cells. Ann N Y Acad Sci 2007; 1099:468. [PMID: 17446487 DOI: 10.1196/annals.1387.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Evrard Nguidjoe
- Laboratory of Pharmacology, Brussels University School of Medicine, B-1070, Brussels, Belgium
| | | |
Collapse
|
23
|
Abstract
Cancer is caused by defects in the mechanisms underlying cell proliferation and cell death. Calcium ions are central to both phenomena, serving as major signalling agents with spatial localization, magnitude and temporal characteristics of calcium signals ultimately determining cell's fate. There are four primary compartments: extracellular space, cytoplasm, endoplasmic reticulum and mitochondria that participate in the cellular Ca2+ circulation. They are separated by own membranes incorporating divers Ca2(+)-handling proteins whose concerted action provides for Ca2+ signals with the spatial and temporal characteristics necessary to account for specific cellular response. The transformation of a normal cell into a cancer cell is associated with a major re-arrangement of Ca2+ pumps, Na/Ca exchangers and Ca2+ channels, which leads to the enhanced proliferation and impaired ability to die. In the present chapter we examine what changes in Ca+ signalling and the mechanisms that support it underlie the passage from normal to pathological cell growth and death control. Understanding this changes and identifying molecular players involved provides new prospects for cancers treatment.
Collapse
Affiliation(s)
- T Capiod
- INSERM U800, Laboratoire de Physiologie Cellulaire, Université des Sciences et Technologies Lille 1, 59655 Villeneuve d'Ascq Cedex, France
| | | | | | | |
Collapse
|
24
|
Chaâbane C, Corvazier E, Bredoux R, Dally S, Raïes A, Villemain A, Dupuy E, Enouf J, Bobe R. Sarco/endoplasmic reticulum Ca2+ATPase type 3 isoforms (SERCA3b and SERCA3f): Distinct roles in cell adhesion and ER stress. Biochem Biophys Res Commun 2006; 345:1377-85. [PMID: 16725111 DOI: 10.1016/j.bbrc.2006.05.054] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Accepted: 05/04/2006] [Indexed: 01/11/2023]
Abstract
Sarco/endoplasmic reticulum Ca(2+)ATPases (SERCAs) pump free Ca(2+) from the cytosol into the endoplasmic reticulum. The human SERCA3 family counts six members named SERCA3a to 3f. However, the exact role of these different isoforms in cellular physiology remains undetermined. In this study, we compared some physiological consequences of SERCA3b and SERCA3f overexpression in HEK-293 cells. We observed that overexpression of SERCA3b affected cell adhesion capacity associated with a major disorganization of F-actin and a decrease in focal adhesion. Furthermore, we found that SERCA3f overexpression resulted in an increase in endoplasmic reticulum stress markers (including processing of X-box-binding protein-1 (XBP-1) mRNA and expression of chaperone glucose-regulated protein 78 (GRP78)). This was associated with the activation of caspase cascade and a higher spontaneous cell death. In conclusion, these data point for the first time to distinct physiological roles of SERCA3 isoforms in cell functions.
Collapse
Affiliation(s)
- Chiraz Chaâbane
- Inserm U.689 E4, IFR-139, Centre de Recherche Cardiovasculaire Inserm Lariboisière, Hôpital Lariboisière, Paris, France
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Turk J, Ramanadham S. The expression and function of a group VIA calcium-independent phospholipase A2 (iPLA2beta) in beta-cells. Can J Physiol Pharmacol 2005; 82:824-32. [PMID: 15573142 DOI: 10.1139/y04-064] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many cells express a Group VIA phospholipase A2, designated iPLA2beta, that does not require calcium for activation, is stimulated by ATP, and is sensitive to inhibition by a bromoenol lactone suicide substrate (BEL). Studies in various cell systems have led to the suggestion that iPLA2beta has a role in phospholipid remodeling, signal transduction, cell proliferation, and apoptosis. We have found that pancreatic islets, beta-cells, and glucose-responsive insulinoma cells express an iPLA2beta that participates in glucose-stimulated insulin secretion but is not involved in membrane phospholipid remodeling. Additionally, recent studies reveal that iPLA2beta is involved in pathways that contribute to beta-cell proliferation and apoptosis, and that various phospholipid-derived mediators are involved in these processes. Detailed characterization of the enzyme suggests that the beta-cells express multiple isoforms of iPLA2beta, and we hypothesize that these participate in different cellular functions.
Collapse
Affiliation(s)
- John Turk
- Mass Spectometry Resource, Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | |
Collapse
|
26
|
Abstract
In brain ischemia, cell destructive necrosis occurs in the core, which in turn links to cell death expansion in the vicinity. Apoptosis, on the other hand, occurs in the surroundings of the core, called the penumbra, several days later. As cells showing apoptosis disappear by microglial phagocytosis in the brain, cell death induced by ischemic stress should eventually be terminated. Thus, the authors propose the hypothesis that the cell death mode switch in the event of brain ischemia is an in vivo self-protective mechanism. The authors attempt to overview the current understanding of the molecular mechanisms of necrosis and apoptosis in relation to the ATP hypothesis, and also introduce novel mechanisms for an in vitro cell death mode switch.
Collapse
Affiliation(s)
- Hiroshi Ueda
- Division of Molecular Pharmacology and Neuroscience, Nagasaki University Graduate School of Biomedical Sciences, Japan.
| | | |
Collapse
|
27
|
Cardozo AK, Ortis F, Storling J, Feng YM, Rasschaert J, Tonnesen M, Van Eylen F, Mandrup-Poulsen T, Herchuelz A, Eizirik DL. Cytokines downregulate the sarcoendoplasmic reticulum pump Ca2+ ATPase 2b and deplete endoplasmic reticulum Ca2+, leading to induction of endoplasmic reticulum stress in pancreatic beta-cells. Diabetes 2005; 54:452-61. [PMID: 15677503 DOI: 10.2337/diabetes.54.2.452] [Citation(s) in RCA: 410] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cytokines and free radicals are mediators of beta-cell death in type 1 diabetes. Under in vitro conditions, interleukin-1beta (IL-1beta) + gamma-interferon (IFN-gamma) induce nitric oxide (NO) production and apoptosis in rodent and human pancreatic beta-cells. We have previously shown, by microarray analysis of primary beta-cells, that IL-1beta + IFN-gamma decrease expression of the mRNA encoding for the sarcoendoplasmic reticulum pump Ca(2+) ATPase 2b (SERCA2b) while inducing expression of the endoplasmic reticulum stress-related and proapoptotic gene CHOP (C/EBP [CCAAT/enhancer binding protein] homologous protein). In the present study we show that cytokine-induced apoptosis and necrosis in primary rat beta-cells and INS-1E cells largely depends on NO production. IL-1beta + IFN-gamma, via NO synthesis, markedly decreased SERCA2b protein expression and depleted ER Ca(2+) stores. Of note, beta-cells showed marked sensitivity to apoptosis induced by SERCA blockers, as compared with fibroblasts. Cytokine-induced ER Ca(2+) depletion was paralleled by an NO-dependent induction of CHOP protein and activation of diverse components of the ER stress response, including activation of inositol-requiring ER-to-nucleus signal kinase 1alpha (IRE1alpha) and PRK (RNA-dependent protein kinase)-like ER kinase (PERK)/activating transcription factor 4 (ATF4), but not ATF6. In contrast, the ER stress-inducing agent thapsigargin triggered these four pathways in parallel. In conclusion, our results suggest that the IL-1beta + IFN-gamma-induced decrease in SERCA2b expression, with subsequent depletion of ER Ca(2+) and activation of the ER stress pathway, is a potential contributory mechanism to beta-cell death.
Collapse
Affiliation(s)
- Alessandra K Cardozo
- Laboratory of Experimental Medicine, Université Libre de Bruxelles, Route de Lennik, 808 CP-618, 1070 Brussels, Belgium.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Kharroubi I, Ladrière L, Cardozo AK, Dogusan Z, Cnop M, Eizirik DL. Free fatty acids and cytokines induce pancreatic beta-cell apoptosis by different mechanisms: role of nuclear factor-kappaB and endoplasmic reticulum stress. Endocrinology 2004; 145:5087-96. [PMID: 15297438 DOI: 10.1210/en.2004-0478] [Citation(s) in RCA: 442] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Apoptosis is probably the main form of beta-cell death in both type 1 diabetes mellitus (T1DM) and T2DM. In T1DM, cytokines contribute to beta-cell destruction through nuclear factor-kappaB (NF-kappaB) activation. Previous studies suggested that in T2DM high glucose and free fatty acids (FFAs) are beta-cell toxic also via NF-kappaB activation. The aims of this study were to clarify whether common mechanisms are involved in FFA- and cytokine-induced beta-cell apoptosis and determine whether TNFalpha, an adipocyte-derived cytokine, potentiates FFA toxicity through enhanced NF-kappaB activation. Apoptosis was induced in insulinoma (INS)-1E cells, rat islets, and fluorescence-activated cell sorting-purified beta-cells by oleate, palmitate, and/or cytokines (IL-1beta, interferon-gamma, TNFalpha). Palmitate and IL-1beta induced a similar percentage of apoptosis in INS-1E cells, whereas oleate was less toxic. TNFalpha did not potentiate FFA toxicity in primary beta-cells. The NF-kappaB-dependent genes inducible nitric oxide synthase and monocyte chemoattractant protein-1 were induced by IL-1beta but not by FFAs. Cytokines activated NF-kappaB in INS-1E and beta-cells, but FFAs did not. Moreover, FFAs did not enhance NF-kappaB activation by TNFalpha. Palmitate and oleate induced C/EBP homologous protein, activating transcription factor-4, and immunoglobulin heavy chain binding protein mRNAs, X-box binding protein-1 alternative splicing, and activation of the activating transcription factor-6 promoter in INS-1E cells, suggesting that FFAs trigger an endoplasmic reticulum (ER) stress response. We conclude that apoptosis is the main mode of FFA- and cytokine-induced beta-cell death but the mechanisms involved are different. Whereas cytokines induce NF-kappaB activation and ER stress (secondary to nitric oxide formation), FFAs activate an ER stress response via an NF-kappaB- and nitric oxide-independent mechanism. Our results argue against a unifying hypothesis for the mechanisms of beta-cell death in T1DM and T2DM.
Collapse
Affiliation(s)
- Ilham Kharroubi
- Laboratory of Experimental Medicine, Université Libre de Bruxelles, Route de Lennik, 808 CP 618, B-1070 Brussels, Belgium
| | | | | | | | | | | |
Collapse
|
29
|
Meyer MH, Etienne W, Meyer RA. Altered mRNA expression of genes related to nerve cell activity in the fracture callus of older rats: A randomized, controlled, microarray study. BMC Musculoskelet Disord 2004; 5:24. [PMID: 15291962 PMCID: PMC512295 DOI: 10.1186/1471-2474-5-24] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2004] [Accepted: 08/03/2004] [Indexed: 01/10/2023] Open
Abstract
Background The time required for radiographic union following femoral fracture increases with age in both humans and rats for unknown reasons. Since abnormalities in fracture innervation will slow skeletal healing, we explored whether abnormal mRNA expression of genes related to nerve cell activity in the older rats was associated with the slowing of skeletal repair. Methods Simple, transverse, mid-shaft, femoral fractures with intramedullary rod fixation were induced in anaesthetized female Sprague-Dawley rats at 6, 26, and 52 weeks of age. At 0, 0.4, 1, 2, 4, and 6 weeks after fracture, a bony segment, one-third the length of the femur, centered on the fracture site, including the external callus, cortical bone, and marrow elements, was harvested. cRNA was prepared and hybridized to 54 Affymetrix U34A microarrays (3/age/time point). Results The mRNA levels of 62 genes related to neural function were affected by fracture. Of the total, 38 genes were altered by fracture to a similar extent at the three ages. In contrast, eight neural genes showed prolonged down-regulation in the older rats compared to the more rapid return to pre-fracture levels in younger rats. Seven genes were up-regulated by fracture more in the younger rats than in the older rats, while nine genes were up-regulated more in the older rats than in the younger. Conclusions mRNA of 24 nerve-related genes responded differently to fracture in older rats compared to young rats. This differential expression may reflect altered cell function at the fracture site that may be causally related to the slowing of fracture healing with age or may be an effect of the delayed healing.
Collapse
Affiliation(s)
- Martha H Meyer
- Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Carolinas Medical Center, P.O. Box 32861, Charlotte, NC 28232-2861 USA
| | - Wiguins Etienne
- Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Carolinas Medical Center, P.O. Box 32861, Charlotte, NC 28232-2861 USA
| | - Ralph A Meyer
- Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Carolinas Medical Center, P.O. Box 32861, Charlotte, NC 28232-2861 USA
| |
Collapse
|
30
|
Szegezdi E, Fitzgerald U, Samali A. Caspase-12 and ER-stress-mediated apoptosis: the story so far. Ann N Y Acad Sci 2004; 1010:186-94. [PMID: 15033718 DOI: 10.1196/annals.1299.032] [Citation(s) in RCA: 358] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The labyrinth of the endoplasmic reticulum (ER) interweaves the cytosol and connects to the nucleus, mitochondria, and the plasma membrane. In the lumen of the ER, the essential function of lipid synthesis, Ca(2+) storage, folding, and maturation of proteins take place. Therefore, the tight regulation and maintenance of ER homeostasis is vital. Disturbance of the Ca(2+) homeostasis during hypoxia, or imbalance between the demand and capacity of the protein-folding apparatus, initiates an adaptive response of the cell, termed the unfolded protein response (UPR, ER stress response). As a result, ER-localized chaperones are induced, protein synthesis is slowed down, and a protein degrading system is initiated. However, if the ER stress cannot be alleviated, it culminates in apoptosis. This paper reviews the newly outlined signaling pathways of the unfolded protein response and describes the central role of caspase-12 in the initiation of cell death. The complex role of the ER and its signaling pathways provides a novel angle on apoptosis research and may offer a key to apoptosis-associated diseases.
Collapse
Affiliation(s)
- Eva Szegezdi
- Cell Stress and Apoptosis Research Group, Department of Biochemistry, National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
| | | | | |
Collapse
|
31
|
Ramanadham S, Hsu FF, Zhang S, Jin C, Bohrer A, Song H, Bao S, Ma Z, Turk J. Apoptosis of insulin-secreting cells induced by endoplasmic reticulum stress is amplified by overexpression of group VIA calcium-independent phospholipase A2 (iPLA2 beta) and suppressed by inhibition of iPLA2 beta. Biochemistry 2004; 43:918-30. [PMID: 14744135 PMCID: PMC3732319 DOI: 10.1021/bi035536m] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The death of insulin-secreting beta-cells that causes type I diabetes mellitus (DM) occurs in part by apoptosis, and apoptosis also contributes to progressive beta-cell dysfunction in type II DM. Recent reports indicate that ER stress-induced apoptosis contributes to beta-cell loss in diabetes. Agents that deplete ER calcium levels induce beta-cell apoptosis by a process that is independent of increases in [Ca(2+)](i). Here we report that the SERCA inhibitor thapsigargin induces apoptosis in INS-1 insulinoma cells and that this is inhibited by a bromoenol lactone (BEL) inhibitor of group VIA calcium-independent phospholipase A(2) (iPLA(2)beta). Overexpression of iPLA(2)beta amplifies thapsigargin-induced apoptosis of INS-1 cells, and this is also suppressed by BEL. The magnitude of thapsigargin-induced INS-1 cell apoptosis correlates with the level of iPLA(2)beta expression in various cell lines, and apoptosis is associated with stimulation of iPLA(2)beta activity, perinuclear accumulation of iPLA(2)beta protein and activity, and caspase-3-catalyzed cleavage of full-length 84 kDa iPLA(2)beta to a 62 kDa product that associates with nuclei. Thapsigargin also induces ceramide accumulation in INS-1 cells, and this response is amplified in cells that overexpress iPLA(2)beta. These findings indicate that iPLA(2)beta participates in ER stress-induced apoptosis, a pathway that promotes beta-cell death in diabetes.
Collapse
Affiliation(s)
- Sasanka Ramanadham
- Mass Spectrometry Resource, Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Washington University School of Medicine, Box 8127, 660 South Euclid Avenue, St. Louis, Missouri 63110, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Eigel BN, Gursahani H, Hadley RW. Na+/Ca2+ exchanger plays a key role in inducing apoptosis after hypoxia in cultured guinea pig ventricular myocytes. Am J Physiol Heart Circ Physiol 2004; 287:H1466-75. [PMID: 15155263 DOI: 10.1152/ajpheart.00874.2003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Altered Na(+)/Ca(2+) exchanger (NCX) protein expression or activity is thought to contribute to various aspects of cardiac pathology. In guinea pig ventricular myocytes, NCX-mediated Ca(2+) entry is almost entirely responsible for Ca(2+) overload during hypoxia-reoxygenation. Because Ca(2+) overload is a common initiator of apoptosis, the purpose of this study was to test the hypotheses that NCX activity is critically involved in initiating apoptosis after hypoxia-reoxygenation and that hypoxia-reoxygenation-induced apoptosis can be modulated by changes in NCX protein expression or activity. An NCX antisense oligonucleotide was used to reduce NCX protein expression in cultured adult guinea pig ventricular myocytes. Caspase-3 activation and cytochrome c release were used as markers of apoptosis. Hypoxia-reoxygenation-induced apoptosis was significantly decreased in antisense-treated myocytes compared with untreated control or nonsense-treated myocytes. Pretreatment of cultured myocytes for 24 h with either endothelin-1 or phenylephrine was found to increase both NCX protein expression and evoked NCX activity as well as enhance hypoxia-reoxygenation-induced apoptosis. Control experiments demonstrated that endothelin-1 and phenylephrine did not induce apoptosis on their own nor did they enhance the apoptotic response in a model of Ca(2+)-dependent, NCX-independent apoptosis. Additional control experiments demonstrated that the NCX antisense oligonucleotide did not alter the apoptotic response of myocytes to either H(2)O(2) or isoproterenol. Taken together, these data suggest that the NCX has a critical and specific role in the initiation of apoptosis after hypoxia-reoxygenation in guinea pig myocytes and that hypoxia-reoxygenation-induced apoptosis is quite sensitive to changes in NCX activity.
Collapse
Affiliation(s)
- B N Eigel
- Dept. of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, MS-371 UKMC, Lexington, KY 40536-0298, USA
| | | | | |
Collapse
|
33
|
Socha L, Silva D, Lesage S, Goodnow C, Petrovsky N. The role of endoplasmic reticulum stress in nonimmune diabetes: NOD.k iHEL, a novel model of beta cell death. Ann N Y Acad Sci 2004; 1005:178-83. [PMID: 14679055 DOI: 10.1196/annals.1288.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The final common pathway in diabetes development is beta cell apoptosis. We herein describe a novel diabetes model based on transgenic NOD.k iHEL mice, wherein male mice develop diabetes due to nonimmune-mediated beta cell death. Histology and electron microscopy confirm endoplasmic reticulum (ER) abnormalities that are consistent with endoplasmic stress caused by the HEL transgene. The NOD.k iHEL model may be particularly useful for studying mechanisms of beta cell death secondary to ER stress and also for testing potential therapies designed to protect beta cells from stress-induced apoptosis. The observation that only male NOD.k iHEL mice develop diabetes and exhibit ER abnormalities is intriguing and suggests these mice may be useful in deciphering the link between hyperandrogenism, insulin resistance, and diabetes.
Collapse
Affiliation(s)
- L Socha
- Autoimmunity Research Unit, The Canberra Hospital, Canberra, Australia
| | | | | | | | | |
Collapse
|
34
|
Kalai M, Lamkanfi M, Denecker G, Boogmans M, Lippens S, Meeus A, Declercq W, Vandenabeele P. Regulation of the expression and processing of caspase-12. J Cell Biol 2003; 162:457-67. [PMID: 12885762 PMCID: PMC2172698 DOI: 10.1083/jcb.200303157] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Phylogenetic analysis clusters caspase-12 with the inflammatory caspases 1 and 11. We analyzed the expression of caspase-12 in mouse embryos, adult organs, and different cell types and tested the effect of interferons (IFNs) and other proinflammatory stimuli. Constitutive expression of the caspase-12 protein was restricted to certain cell types, such as epithelial cells, primary fibroblasts, and L929 fibrosarcoma cells. In fibroblasts and B16/B16 melanoma cells, caspase-12 expression is stimulated by IFN-gamma but not by IFN-alpha or -beta. The effect is increased further when IFN-gamma is combined with TNF, lipopolysaccharide (LPS), or dsRNA. These stimuli also induce caspase-1 and -11 but inhibit the expression of caspase-3 and -9. In contrast to caspase-1 and -11, no caspase-12 protein was detected in macrophages in any of these treatments. Transient overexpression of full-length caspase-12 leads to proteolytic processing of the enzyme and apoptosis. Similar processing occurs in TNF-, LPS-, Fas ligand-, and thapsigargin (Tg)-induced apoptosis. However, B16/B16 melanoma cells die when treated with the ER stress-inducing agent Tg whether they express caspase-12 or not.
Collapse
Affiliation(s)
- Michael Kalai
- Department of Molecular Biomedical Research, Unit of Molecular Signalling and Cell Death, Ghent University, Ledeganckstraat 35, B-9000 Ghent, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Abstract
The crucial role of cell death in many diseases is obvious and has spurred intense research to understand the regulation of apoptotic pathways. Caspase activation is central to many of the apoptotic pathways. In recent years, the study of the regulation of caspase activation and activity in various cell lines and in diseases has revealed highly complex mechanisms regulating cell survival or cell death. In this review, the major natural cellular anticaspase factors are described with particular attention to the inhibitors that prevent active caspases from committing the cell to irreversible destruction. The major group of caspase inhibitors known is the inhibitor of apoptosis proteins (IAP) and this review describes the characteristics of IAP, regulation of IAP expression, and mechanisms of action of IAP. However, other proteins including Bcl-2 family members, heat shock proteins, caspase-like decoy, calpains and proteases, and lipid moieties in the form of phosphoinositides also can function as caspase inhibitors. The current knowledge of the inhibition of these non-IAP factors is described herein.
Collapse
Affiliation(s)
- Andréa C LeBlanc
- Department of Neurology, The Bloomfield Center for Research in Aging, H3T 1E2, Montreal, Quebec, Canada.
| |
Collapse
|
36
|
Glazner GW, Fernyhough P. Neuronal survival in the balance: are endoplasmic reticulum membrane proteins the fulcrum? Cell Calcium 2002; 32:421-33. [PMID: 12543101 DOI: 10.1016/s014341600200194x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- G W Glazner
- Faculty of Medicine, University of Manitoba, St. Boniface Research Centre, 4052-351 Tache Avenue, Man., R2K-3V3, Winnipeg, Canada.
| | | |
Collapse
|
37
|
Herchuelz A, Diaz-Horta O, Van Eylen F. Na/Ca exchange in function, growth, and demise of beta-cells. Ann N Y Acad Sci 2002; 976:315-24. [PMID: 12502574 DOI: 10.1111/j.1749-6632.2002.tb04754.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent knowledge concerning the Na/Ca exchanger (NCX) in the pancreatic beta-cell is reviewed. The beta-cell expresses various NCX1 splice variants in a species-specific pattern (NCX1.3 and 1.7 in the rat; NCX1.2, 1.3, and 1.7 in the mouse) and in variable and different proportions. In the rat beta-cell, the exchanger displays a high capacity, accounts for about 70% of Ca(2+) extrusion, and participates in Ca(2+) inflow during membrane depolarization. In the mouse, however, the contribution of the exchanger to Ca(2+) extrusion is more modest, and to Ca(2+) inflow, less evident. The exchanger has a stoichiometry of 3 Na(+) for 1 Ca(2+), is electrogenic, and displays a reversal potential at -20 mV. Although being of low magnitude, the current generated by the exchanger shapes glucose-induced beta-cell electrical activity and intracellular Ca(2+) oscillations. Intracellular Ca(2+) may also trigger apoptosis. For instance, overexpression of the exchanger increases Ca(2+)-dependent and Ca(2+)-independent beta-cell death by apoptosis, a phenomenon resulting from the depletion of ER Ca(2+) stores with subsequent activation of caspase-12. Na/Ca exchange overexpression also reduces beta-cell growth. Hence, the Na/Ca exchanger is a versatile system that appears to play an important role in the function, growth, and demise of the beta-cell.
Collapse
Affiliation(s)
- André Herchuelz
- Laboratory of Pharmacology, Brussels University School of Medicine, B-1070, Brussels, Belgium.
| | | | | |
Collapse
|
38
|
Current literature in diabetes. Diabetes Metab Res Rev 2002; 18:419-26. [PMID: 12397584 DOI: 10.1002/dmrr.247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
39
|
Kamagate A, Herchuelz A, Van Eylen F. Plasma membrane Ca(2+)-ATPase overexpression reduces Ca(2+) oscillations and increases insulin release induced by glucose in insulin-secreting BRIN-BD11 cells. Diabetes 2002; 51:2773-88. [PMID: 12196471 DOI: 10.2337/diabetes.51.9.2773] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In the mouse beta-cell, glucose generates large amplitude oscillations of the cytosolic-free Ca(2+) concentration ([Ca(2+)](i)) that are synchronous to insulin release oscillations. To examine the role played by [ Ca(2+)](i) oscillations in the process of insulin release, we examined the effect of plasma membrane Ca(2+)-ATPase (PMCA) overexpression on glucose-induced Ca(2+) oscillations and insulin release in BRIN-BD11 cells. BRIN-BD11 cells were stably transfected with PMCA2wb. Overexpression could be assessed at the mRNA and protein level, with appropriate targeting to the plasma membrane assessed by immunofluorescence and the increase in PMCA activity. In response to K(+), overexpressing cells showed a markedly reduced rise in [Ca(2+)](i). In response to glucose, control cells showed large amplitude [Ca(2+)](i) oscillations, whereas overexpressing cells showed markedly reduced increases in [Ca(2+)](i) without such large oscillations. Suppression of [Ca(2+)](i) oscillations was accompanied by an increase in glucose metabolism and insulin release that remained oscillatory despite having a lower periodicity. Hence, [Ca(2+)] (i) oscillations appear unnecessary for glucose-induced insulin release and may even be less favorable than a stable increase in [ Ca(2+)](i) for optimal hormone secretion. [Ca(2+)](i) oscillations do not directly drive insulin release oscillations but may nevertheless intervene in the fine regulation of such oscillations.
Collapse
Affiliation(s)
- Adama Kamagate
- Laboratory of Pharmacology, Brussels University School of Medicine, Brussels, Belgium
| | | | | |
Collapse
|