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Noble M, Lin QT, Sirko C, Houpt JA, Novello MJ, Stathopulos PB. Structural Mechanisms of Store-Operated and Mitochondrial Calcium Regulation: Initiation Points for Drug Discovery. Int J Mol Sci 2020; 21:E3642. [PMID: 32455637 PMCID: PMC7279490 DOI: 10.3390/ijms21103642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/11/2020] [Accepted: 05/17/2020] [Indexed: 12/18/2022] Open
Abstract
Calcium (Ca2+) is a universal signaling ion that is essential for the life and death processes of all eukaryotes. In humans, numerous cell stimulation pathways lead to the mobilization of sarco/endoplasmic reticulum (S/ER) stored Ca2+, resulting in the propagation of Ca2+ signals through the activation of processes, such as store-operated Ca2+ entry (SOCE). SOCE provides a sustained Ca2+ entry into the cytosol; moreover, the uptake of SOCE-mediated Ca2+ by mitochondria can shape cytosolic Ca2+ signals, function as a feedback signal for the SOCE molecular machinery, and drive numerous mitochondrial processes, including adenosine triphosphate (ATP) production and distinct cell death pathways. In recent years, tremendous progress has been made in identifying the proteins mediating these signaling pathways and elucidating molecular structures, invaluable for understanding the underlying mechanisms of function. Nevertheless, there remains a disconnect between using this accumulating protein structural knowledge and the design of new research tools and therapies. In this review, we provide an overview of the Ca2+ signaling pathways that are involved in mediating S/ER stored Ca2+ release, SOCE, and mitochondrial Ca2+ uptake, as well as pinpoint multiple levels of crosstalk between these pathways. Further, we highlight the significant protein structures elucidated in recent years controlling these Ca2+ signaling pathways. Finally, we describe a simple strategy that aimed at applying the protein structural data to initiating drug design.
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Affiliation(s)
- Megan Noble
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Qi-Tong Lin
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Christian Sirko
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Jacob A. Houpt
- Department of Medicine, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada;
| | - Matthew J. Novello
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Peter B. Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
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Lesnefsky EJ, Chen Q, Tandler B, Hoppel CL. Mitochondrial Dysfunction and Myocardial Ischemia-Reperfusion: Implications for Novel Therapies. Annu Rev Pharmacol Toxicol 2017; 57:535-565. [PMID: 27860548 PMCID: PMC11060135 DOI: 10.1146/annurev-pharmtox-010715-103335] [Citation(s) in RCA: 274] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondria have emerged as key participants in and regulators of myocardial injury during ischemia and reperfusion. This review examines the sites of damage to cardiac mitochondria during ischemia and focuses on the impact of these defects. The concept that mitochondrial damage during ischemia leads to cardiac injury during reperfusion is addressed. The mechanisms that translate ischemic mitochondrial injury into cellular damage, during both ischemia and early reperfusion, are examined. Next, we discuss strategies that modulate and counteract these mechanisms of mitochondrial-driven injury. The new concept that mitochondria are not merely stochastic sites of oxidative and calcium-mediated injury but that they activate cellular responses of mitochondrial remodeling and cellular reactions that modulate the balance between cell death and recovery is reviewed, and the therapeutic implications of this concept are discussed.
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Affiliation(s)
- Edward J Lesnefsky
- Department of Medicine, Division of Cardiology, Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia 23298; ,
- Medical Service, McGuire Veterans Affairs Medical Center, Richmond, Virginia 23249;
| | - Qun Chen
- Department of Medicine, Division of Cardiology, Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia 23298; ,
| | - Bernard Tandler
- Department of Biological Sciences, Case Western Reserve University School of Dental Medicine, Cleveland, Ohio 44106;
| | - Charles L Hoppel
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106;
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
- Center for Mitochondrial Disease, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
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Vasques ER, Cunha JEM, Coelho AMM, Sampietre SN, Patzina RA, Abdo EE, Nader HB, Tersariol ILS, Lima MA, Godoy CMG, Rodrigues T, Chaib E, D’Albuquerque LAC. Trisulfate Disaccharide Decreases Calcium Overload and Protects Liver Injury Secondary to Liver Ischemia/Reperfusion. PLoS One 2016; 11:e0149630. [PMID: 26901764 PMCID: PMC4763191 DOI: 10.1371/journal.pone.0149630] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 02/03/2016] [Indexed: 12/14/2022] Open
Abstract
Background Ischemia and reperfusion (I/R) causes tissue damage and intracellular calcium levels are a factor of cell death. Sodium calcium exchanger (NCX) regulates calcium extrusion and Trisulfated Disaccharide (TD) acts on NCX decreasing intracellular calcium through the inhibition of the exchange inhibitory peptide (XIP). Objectives The aims of this research are to evaluate TD effects in liver injury secondary to I/R in animals and in vitro action on cytosolic calcium of hepatocytes cultures under calcium overload. Methods Wistar rats submitted to partial liver ischemia were divided in groups: Control: (n = 10): surgical manipulation with no liver ischemia; Saline: (n = 15): rats receiving IV saline before reperfusion; and TD: (n = 15): rats receiving IV TD before reperfusion. Four hours after reperfusion, serum levels of AST, ALT, TNF-α, IL-6, and IL-10 were measured. Liver tissue samples were collected for mitochondrial function and malondialdehyde (MDA) content. Pulmonary vascular permeability and histologic parameters of liver were determined. TD effect on cytosolic calcium was evaluated in BRL3A hepatic rat cell cultures stimulated by thapsigargin pre and after treatment with TD. Results AST, ALT, cytokines, liver MDA, mitochondrial dysfunction and hepatic histologic injury scores were less in TD group when compared to Saline Group (p<0.05) with no differences in pulmonary vascular permeability. In culture cells, TD diminished the intracellular calcium raise and prevented the calcium increase pre and after treatment with thapsigargin, respectively. Conclusion TD decreases liver cell damage, preserves mitochondrial function and increases hepatic tolerance to I/R injury by calcium extrusion in Ca2+ overload situations.
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Affiliation(s)
- Enio Rodrigues Vasques
- Department of Gastroenterology (LIM 37), Medical School, University of Sao Paulo (USP), Sao Paulo, Brazil
- * E-mail:
| | | | - Ana Maria Mendonca Coelho
- Department of Gastroenterology (LIM 37), Medical School, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - Sandra N. Sampietre
- Department of Gastroenterology (LIM 37), Medical School, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - Rosely Antunes Patzina
- Department of Gastroenterology (LIM 37), Medical School, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - Emilio Elias Abdo
- Department of Gastroenterology (LIM 37), Medical School, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - Helena B. Nader
- Department of Biochemistry, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
| | - Ivarne L. S. Tersariol
- Department of Biochemistry, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
| | - Marcelo Andrade Lima
- Department of Biochemistry, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
| | - Carlos M. G. Godoy
- Department of Science and Technology, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
| | - Tiago Rodrigues
- Center of Natural and Human Sciences, Federal University of ABC, Sao Paulo, Brazil
| | - Eleazar Chaib
- Department of Gastroenterology (LIM 37), Medical School, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - Luiz A. C. D’Albuquerque
- Department of Gastroenterology (LIM 37), Medical School, University of Sao Paulo (USP), Sao Paulo, Brazil
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Pless-Petig G, Metzenmacher M, Türk TR, Rauen U. Aggravation of cold-induced injury in Vero-B4 cells by RPMI 1640 medium - identification of the responsible medium components. BMC Biotechnol 2012; 12:73. [PMID: 23046946 PMCID: PMC3534012 DOI: 10.1186/1472-6750-12-73] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 10/04/2012] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND In modern biotechnology, there is a need for pausing cell lines by cold storage to adapt large-scale cell cultures to the variable demand for their products. We compared various cell culture media/solutions for cold storage of Vero-B4 kidney cells, a cell line widely used in biotechnology. RESULTS Cold storage in RPMI 1640 medium, a recommended cell culture medium for Vero-B4 cells, surprisingly, strongly enhanced cold-induced cell injury in these cells in comparison to cold storage in Krebs-Henseleit buffer or other cell culture media (DMEM, L-15 and M199). Manufacturer, batch, medium supplements and the most likely components with concentrations outside the range of the other media/solutions (vitamin B12, inositol, biotin, p-aminobenzoic acid) did not cause this aggravation of cold-induced injury in RPMI 1640. However, a modified Krebs-Henseleit buffer with a low calcium concentration (0.42 mM), a high concentration of inorganic phosphate (5.6 mM), and glucose (11.1 mM; i.e. concentrations as in RPMI 1640) evoked a cell injury and loss of metabolic function corresponding to that observed in RPMI 1640. Deferoxamine improved cell survival and preserved metabolic function in modified Krebs-Henseleit buffer as well as in RPMI 1640. Similar Ca2+ and phosphate concentrations did not increase cold-induced cell injury in the kidney cell line LLC-PK1, porcine aortic endothelial cells or rat hepatocytes. However, more extreme conditions (Ca2+ was nominally absent and phosphate concentration raised to 25 mM as in the organ preservation solution University of Wisconsin solution) also increased cold-induced injury in rat hepatocytes and porcine aortic endothelial cells. CONCLUSION These data suggest that the combination of low calcium and high phosphate concentrations in the presence of glucose enhances cold-induced, iron-dependent injury drastically in Vero-B4 cells, and that a tendency for this pathomechanism also exists in other cell types.
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Affiliation(s)
- Gesine Pless-Petig
- Institut für Physiologische Chemie, Universitätsklinikum Essen, Universität Duisburg-Essen, Hufelandstr, 55, 45122, Essen, Germany
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Díaz-Juárez J, Hernández-Muñoz R. The role of calcium and nitric oxide during liver enzyme release induced by increased physical forces as evidenced in partially hepatectomized rats. Liver Transpl 2011; 17:334-43. [PMID: 21384517 DOI: 10.1002/lt.22238] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Although increased plasma enzyme activities could be diagnostic for tissue damage, the mechanisms controlling cellular enzyme release remain poorly understood. We found a selective and drastic elevation of serum enzyme activities accompanying rat liver regeneration after partial hepatectomy (PH), apparently controlled by a mechanism dependent on flow-bearing physical forces. In fact, this study assesses a putative role of calcium mobilization and nitric oxide (NO) production underlying rat liver enzyme release. The role of increased shear stress (by enhancing viscosity during perfusion) and the participation of cell calcium and NO were tested in isolated livers subjected to increasing flow rate. After PH, there was a drastic elevation of serum activities for liver enzyme markers, clearly predominating those of mitochondrial localization. Liver enzyme release largely depended on extracellular calcium entry, probably mediated by stretch-sensitive calcium channels, as well as by increasing NO production. However, these effects were differentially observed when comparing liver enzymes from cytoplasmic or mitochondrial compartments. Moreover, a possible role for cell-mediated mechanotransduction in liver enzyme release was suggested by increasing shear stress (high viscosity), which also selectively affected the release of the enzymes tested. Therefore, we show, for the first time, that flow-induced shear stress can control the amount of hepatic enzymes released into the bloodstream, which is largely regulated through modifications in cell calcium mobilization and production of liver NO, events markedly elevated in the proliferating rat liver.
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Affiliation(s)
- Julieta Díaz-Juárez
- Department of Pharmacology, Instituto Nacional Cardiología Ignacio Chávez, Mexico City, Distrito Federal, Mexico
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Little evidence for a major role of Ca2+ in cold-induced injury of liver cells. Cryobiology 2008; 56:103-13. [DOI: 10.1016/j.cryobiol.2007.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 11/08/2007] [Accepted: 11/22/2007] [Indexed: 11/17/2022]
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Nicoud IB, Knox CD, Jones CM, Anderson CD, Pierce JM, Belous AE, Earl TM, Chari RS. 2-APB protects against liver ischemia-reperfusion injury by reducing cellular and mitochondrial calcium uptake. Am J Physiol Gastrointest Liver Physiol 2007; 293:G623-30. [PMID: 17627971 DOI: 10.1152/ajpgi.00521.2006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ischemia-reperfusion (I/R) injury is a commonly encountered clinical problem in liver surgery and transplantation. The pathogenesis of I/R injury is multifactorial, but mitochondrial Ca(2+) overload plays a central role. We have previously defined a novel pathway for mitochondrial Ca(2+) handling and now further characterize this pathway and investigate a novel Ca(2+)-channel inhibitor, 2-aminoethoxydiphenyl borate (2-APB), for preventing hepatic I/R injury. The effect of 2-APB on cellular and mitochondrial Ca(2+) uptake was evaluated in vitro by using (45)Ca(2+). Subsequently, 2-APB (2 mg/kg) or vehicle was injected into the portal vein of anesthetized rats either before or following 1 h of inflow occlusion to 70% of the liver. After 3 h of reperfusion, liver injury was assessed enzymatically and histologically. Hep G2 cells transfected with green fluorescent protein-tagged cytochrome c were used to evaluate mitochondrial permeability. 2-APB dose-dependently blocked Ca(2+) uptake in isolated liver mitochondria and reduced cellular Ca(2+) accumulation in Hep G2 cells. In vivo I/R increased liver enzymes 10-fold, and 2-APB prevented this when administered pre- or postischemia. 2-APB significantly reduced cellular damage determined by hematoxylin and eosin and terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling staining of liver tissue. In vitro I/R caused a dissociation between cytochrome c and mitochondria in Hep G2 cells that was prevented by administration of 2-APB. These data further establish the role of cellular Ca(2+) uptake and subsequent mitochondrial Ca(2+) overload in I/R injury and identify 2-APB as a novel pharmacological inhibitor of liver I/R injury even when administered following a prolonged ischemic insult.
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Affiliation(s)
- I B Nicoud
- Department of Surgery, Division of Hepatobiliary Surgery and Liver Transplantation, Suite 801 Oxford House, 1313 21st Avenue South, Vanderbilt University Medical Center, Nashville, TN 37232-4753, USA
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Kwon YS, Foley JD, Murphy CJ, McAnulty JF. The effect of trophic factor supplementation on cold ischemia-induced early apoptotic changes. Transplantation 2007; 83:91-4. [PMID: 17220800 DOI: 10.1097/01.tp.0000242524.35562.4b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have previously shown that trophic factor supplementation (TFS) of University of Wisconsin (UW) solution enhanced kidney viability after cold storage. Here, we use an in vitro model to study the effect of TFS on early apoptotic changes after cold ischemic storage. Mitochondrial membrane potential was determined by fluorescence intensity in primary canine kidney tubule cells, Madin-Darby canine kidney cells, and human umbilical vein endothelial cells. In addition, caspase 3 enzyme activity assay and immunofluorescence staining were performed to evaluate apoptosis. There was a 15% increase in mitochondrial membrane potential in human umbilical vein endothelial cells stored in trophic factor supplemented University of Wisconsin solution after four-hour rewarming (P<0.05). TFS suppressed caspase 3 enzyme activity and activation in human umbilical vein endothelial cells. We confirmed that the presence of TFS in UW solution has a beneficial effect by protecting mitochondrial function and reducing early apoptotic changes in vascular endothelial cells.
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Affiliation(s)
- Young Sam Kwon
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin 53706, USA
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Knox CD, Pierce JM, Nicoud IB, Belous AE, Jones CM, Anderson CD, Chari RS. Inhibition of phospholipase C attenuates liver mitochondrial calcium overload following cold ischemia. Transplantation 2006; 81:567-72. [PMID: 16495805 DOI: 10.1097/01.tp.0000199267.98971.77] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Graft failure due to cold ischemia (CI) injury remains a significant problem during liver transplantation. During CI, the consumption of ATP and the increase in cellular Ca concentration may result in mitochondrial Ca (mCa) overload through the mCa uniporter, which can ultimately lead to apoptosis and graft nonfunction. We recently identified phospholipase C-dl (PLC-dl) as a novel regulator of mCa uptake in the liver, and now extend those studies to examine the role of mitochondrial PLC in liver CI injury. METHODS Rat livers were perfused with University of Wisconsin (UW) solution. Half was homogenized immediately; the other half was cold-stored for 24 hr in UW. Mitochondria were extracted by differential centrifugation and incubated in buffer containing ATP and 0.1 or 0.2 microM Ca. The selective PLC inhibitor, U-73122, was added to determine the effects of PLC inhibition on mCa uptake following CI. Western blots and densitometry quantified mitochondrial PLC expression. Mito Tracker Red fluorescence microscopy was used to verify mitochondrial transmembrane potential. RESULTS Twenty-four hour CI caused a significant increase in mCa uptake (P<0.001), and increasing extramitochondrial Ca potentiated this effect. The PLC inhibitor, U-73122, decreased mCa uptake in nonischemic mitochondria (P<0.001), and had a greater effect on CI mitochondria (P<0.001). Mitochondrial PLC-dl expression increased 175+/-75% following CI (P<0.05). CONCLUSIONS These data demonstrate that PLC-dl is essential for mCa uptake following CI, and that the PLC pathway may be sensitized by CI. The CI-induced increase in mitochondrial PLC-delta1 expression represents a novel mechanism whereby mCa uptake can increase independently of cytosolic conditions.
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Affiliation(s)
- Clayton D Knox
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Abstract
Microvascular dysfunction mediates many of the local and systemic consequences of ischemic-reperfusion (I/R) injury, with a spectrum of changes specific to arterioles, capillaries, and venules. This review discusses the specific changes in the endothelium during I/R injury; describes the differential responses of the various levels of the vasculature including arterioles, capillaries, and venules; and explores mechanisms for remote organ injury. Vascular dysfunction is largely a consequence of changes in the endothelial cells themselves, affecting the integrity of barrier function, cytokine and adhesion molecule expression, and vascular tone. The bioavailability of nitric oxide, an important mediator of vasodilation, is profoundly decreased during the reperfusion period, resulting in impaired vasodilation of arterioles. Release of inflammatory mediators and increased expression of adhesion molecules initiate inflammatory and coagulation cascades that culminate in the occlusion of capillaries, known as the "no-reflow''" phenomenon. In postcapillary venules, the recruitment and transmigration of leukocytes further compromise the integrity of the endothelial barrier and increase the oxidative burden, resulting in leakage and tissue edema. I/R injury can have significant and untoward consequences beyond the affected tissue, with such conditions as systemic inflammatory response syndrome. This review highlights recent progress in understanding of the varied phenomena of vascular dysfunction in I/R injury and some promising advances in the understanding and application of ischemic preconditioning and other potential therapies.
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Affiliation(s)
- John B Seal
- Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA
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Anderson CD, Pierce J, Nicoud I, Belous A, Knox CD, Chari RS. Modulation of mitochondrial calcium management attenuates hepatic warm ischemia-reperfusion injury. Liver Transpl 2005; 11:663-8. [PMID: 15915483 DOI: 10.1002/lt.20407] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hepatic warm ischemia and reperfusion (IR) injury occurs in many clinical situations and has an important link to subsequent hepatic failure. The pathogenesis of this injury involves numerous pathways, including mitochondrial-associated apoptosis. We studied the effect of mitochondrial calcium uptake inhibition on hepatic IR injury using the specific mitochondrial calcium uptake inhibitor, ruthenium red (RR). Rats were subjected to 1 hour of 70% warm hepatic ischemia following RR pretreatment or vehicle injection. Sham-operated animals served as controls. Analysis was performed at 15 minutes, 1 hour, 3 hours, or 6 hours after reperfusion. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations were determined. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining was performed to assess apoptosis, and hepatocellular necrosis was semiquantitated from hematoxylin and eosin-stained tissue sections. RR pretreatment significantly decreased both AST and ALT serum levels after 6 hours of reperfusion (AST: 1,556 +/- 181 U/L vs. 597 +/- 121 U/L, P = 0.005; ALT: 1,118 +/- 187 U/L vs. 294 +/- 39 U/L, P = 0.005). Apoptosis was observed within 15 minutes of reperfusion in vehicle-pretreated animals and peaked after 3 hours of reperfusion (98 +/- 21 cells/high-power field [hpf]). Apoptosis was inhibited at all time points by RR pretreatment. Histologic evidence of necrosis was not observed prior to 3 hours of reperfusion (23% +/- 4%), and maximal necrosis was observed after 6 hours of reperfusion (26% +/- 1% percent area). RR pretreatment significantly decreased the necrotic percent area at both the 3-hour and the 6-hour time points (4.2% +/- 2%; 3.7% +/- 1%, respectively). Hepatic IR injury resulted in both apoptotic and necrotic cell death, which were attenuated by RR pretreatment. In conclusion, these observations implicate mitochondrial calcium uptake in the pathogenesis of hepatic IR injury.
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Affiliation(s)
- Christopher D Anderson
- Department of Surgery, Division of Hepatobiliary Surgery and Liver Transplantation, Vanderbilt University Medical Center, Nashville, TN 37232-4753, USA
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Anderson CD, Belous A, Pierce J, Nicoud IB, Knox C, Wakata A, Pinson CW, Chari RS. Mitochondrial calcium uptake regulates cold preservation-induced Bax translocation and early reperfusion apoptosis. Am J Transplant 2004; 4:352-62. [PMID: 14961987 DOI: 10.1111/j.1600-6143.2004.00357.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Mitochondrial calcium (mCa + 2) overload occurs during cold preservation and is an integral part of mitochondrial-dependent apoptotic pathways. We investigated the role of mCa + 2 overload in cell death following hypothermic storage using HepG2 cells stored in normoxic-hypothermic (4 degrees C) or hypoxic (< 0.1% O2)-hypothermic Belzer storage solution. Cells were stored for 6 h, with or without 10 microM ruthenium red (mCa + 2 uniporter inhibitor) followed by rewarming in oxygenated media at 37 degrees C. Cytoplasmic cytochrome c levels were studied by Western analysis and by fluorescent microscopy after transfection of cytochrome c-GFP expression plasmid. Immunofluorescence determined the intracellular, spatio-temporal distribution of Bax, and TUNEL staining was used to evaluate cell death after 180 min of rewarming. Caspase activation was evaluated using Western analysis and a caspase 3 activity assay. Bax translocation, cytochrome c release, and early rewarming cell death occurred following hypothermic storage and were exacerbated by hypoxia. Caspase 3 activation did not occur following hypothermic storage. Blockade of mCa + 2 uptake prevented Bax translocation, cytochrome c release, and early rewarming cell death. These studies demonstrate that mCa + 2 uptake during hypothermic storage, both hypoxic and normoxic, contributes to early rewarming apoptosis by triggering Bax translocation to mitochondria and cytochrome c release.
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Affiliation(s)
- Christopher D Anderson
- Division of Hepatobiliary Surgery and Liver Transplantation, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
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Kerkweg U, Jacob M, De Groot H, Mannherz HG, Rauen U. Cold-induced apoptosis of rat liver endothelial cells: contribution of mitochondrial alterations. Transplantation 2003; 76:501-8. [PMID: 12923435 DOI: 10.1097/01.tp.0000069830.78758.1c] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Maintenance of the integrity of the vascular endothelium is a critical issue in liver preservation, but hypothermia, applied for cellular protection, induces apoptotic cell death in liver endothelial cells. This cold-induced apoptosis is mediated by an iron-dependent formation of reactive oxygen species. Here, we study the involvement of mitochondria in this process. METHODS Cultured rat liver endothelial cells were incubated in cold University of Wisconsin solution for 18 hr and subsequently rewarmed in cell culture medium. Mitochondrial morphology and membrane potential were evaluated using laser scanning microscopy. RESULTS During cold incubation in University of Wisconsin solution, a marked, progressive mitochondrial shortening and a reduction in mitochondrial membrane potential occurred. Rewarming of the cells led to mitochondrial ultracondensation, complete loss of the mitochondrial membrane potential, and subsequent apoptotic cell death. The inhibitors of mitochondrial permeability transition, trifluoperazine and fructose, or iron chelation with deferoxamine did not affect mitochondrial shortening during cold incubation but inhibited ultracondensation, loss of mitochondrial membrane potential, and loss of viability during rewarming. Moreover, in these protected cells, an almost complete reestablishment of the mitochondrial membrane potential and morphology could be observed; the few mitochondria that were irreversibly damaged were incorporated into autophagosomes during cellular recovery. CONCLUSION Two apparently independent mitochondrial alterations take place during cold incubation and subsequent rewarming of liver endothelial cells. Cold-induced mitochondrial shortening represents a reversible process, whereas iron-mediated mitochondrial permeability transition and ultracondensation during rewarming are irreversible and constitute an important mediator of cold-induced apoptosis.
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Affiliation(s)
- Uta Kerkweg
- Institut für Physiologische Chemie, Universitätsklinikum, Essen, Germany
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Belous A, Knox C, Nicoud IB, Pierce J, Anderson C, Pinson CW, Chari RS. Reversed activity of mitochondrial adenine nucleotide translocator in ischemia-reperfusion. Transplantation 2003; 75:1717-23. [PMID: 12777862 DOI: 10.1097/01.tp.0000063829.35871.ce] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Graft dysfunction as a result of preservation injury remains a major clinical problem in liver transplantation. This is related in part to accumulation of mitochondrial calcium. In an attempt to sustain cell and mitochondrial integrity during ischemia, intramitochondrial F(0)F(1) adenosine triphosphate (ATP) synthase reverses its activity and hydrolyzes ATP to maintain the mitochondrial transmembrane potential (mdeltapsi). It is not known how cytoplasmic ATP becomes available for hydrolysis by this enzyme. The authors hypothesized that mitochondrial adenine nucleotide translocator (ANT) reverses its activity during ischemia, making cytoplasmic ATP available for hydrolysis by F(0)F(1) ATP synthase. METHODS Rat livers were perfused with cold University of Wisconsin solution at 4 degrees C (39.2 degrees F)through the portal vein and processed immediately or after 24 hr of cold storage. Mitochondria were separated by differential centrifugation. ATP-dependent mitochondrial calcium-45 (45Ca)2+ uptake was determined after incubation with ATP (5 mM) or adenosine diphosphate (ADP) (5 mM) with or without 15 microM of bongkrekic acid (BA), an ANT blocker; the nonhydrolyzable analog of ATP (adenosine 5'-beta,gamma-imidotriphosphate [AMP-PNP]) served as the negative control. All measurements were performed in triplicate. Student t test, P<0.05 was taken as significant. RESULTS Inhibition of ANT by BA prevents mitochondrial Ca2+ accumulation in the presence of ATP and high 45Ca2+ concentrations, and increased extramitochondrial 45Ca2+ stimulated mitochondrial 45Ca2+ uptake in the presence of ATP but not ADP, AMP-PNP, or BA. CONCLUSIONS These data demonstrate that ANT plays an important role in mitochondrial Ca2+ uptake under ischemic conditions by reversing its activity and allowing transport of extramitochondrial ATP into the matrix for hydrolysis by reversed F(0)F(1) ATP synthase.
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Affiliation(s)
- Andrey Belous
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232-4753, USA
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Belous A, Knox C, Nicoud IB, Pierce J, Anderson C, Pinson CW, Chari RS. Altered ATP-dependent mitochondrial Ca2+ uptake in cold ischemia is attenuated by ruthenium red. J Surg Res 2003; 111:284-9. [PMID: 12850475 DOI: 10.1016/s0022-4804(03)00092-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Graft dysfunction as a result of preservation injury remains a major clinical problem in liver transplantation. This is related in part to accumulation of mitochondrial calcium (Ca(2+)), which has been linked to activation of proapoptotic factors. We hypothesized that cold ischemia increases mitochondrial Ca(2+) uptake in a concentration dependent fashion and that ruthenium red (RR) will attenuate these changes by inhibiting the mitochondrial Ca(2+) uniporter. METHODS Rat livers perfused with cold University of Wisconsin (UW) solution (4 degrees C) with or without RR (10 microM) via the portal vein (n = 3 per group) were processed immediately (no ischemia) or after 24 h cold-storage (24 h cold ischemia). Mitochondria were separated by differential centrifugation, and adenosine triphosphate (ATP)-dependent (45)Ca(2+) uptake was determined in the presence of ATP (5 mM), adenosine diphosphate (ADP), or adenosine 5'-beta,gamma-imidotriphosphate (AMP-PNP); variable concentrations of extramitochondrial (45)Ca(2+) were used. All measurements were performed in triplicate. Student's t test with P < 0.05 was taken as significant. RESULTS Our data demonstrate the following: 1) ATP-dependent (45)Ca(2+) uptake in mitochondria separated from livers following 24 h of cold ischemia in UW alone was higher than in mitochondria isolated from non-ischemic livers; the increased uptake was dependent on the concentration of (45)Ca(2+) in the incubation buffer. 2) There was no difference in ATP-dependent (45)Ca(2+) uptake between nonischemic mitochondria and those separated from livers stored in UW-RR for 24 h. 3) (45)Ca(2+) uptake in mitochondria from livers subjected to 24 h of cold ischemia in UW-RR was significantly lower compared to those from livers stored in UW alone when (45)Ca(2+) concentrations were greater than 1 microM. CONCLUSION 1) Cold ischemia affects mitochondrial Ca(2+) handling, especially when it is challenged by high extramitochondrial Ca(2+) concentrations. 2) The addition of RR in preservation solution attenuates the effects of cold ischemia on mitochondrial Ca(2+) handling. 3) Inhibition of mitochondrial Ca(2+) uniporter with RR protects mitochondria from Ca(2+) overload at high Ca(2+) concentrations. These findings may offer a potentially effective strategy for prevention of ischemia-reperfusion injury in liver transplantation.
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Affiliation(s)
- Andrey Belous
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37232-4753, USA
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Zablocki K, Makowska A, Duszyński J. pH-dependent effect of mitochondria on calcium influx into Jurkat cells; a novel mechanism of cell protection against calcium entry during energy stress. Cell Calcium 2003; 33:91-9. [PMID: 12531185 DOI: 10.1016/s0143-4160(02)00202-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Loss of the mitochondrial membrane potential results in a significant inhibition of calcium influx through calcium release-activated channels (CRAC) in Jurkat cells suspended in the medium of pH lower than 7.4. This effect disappears when the medium pH increases. Alkalinisation of the cytosol achieved by the addition of NH(4)Cl to the cells pretreated with thapsigargin, CCCP and CaCl(2), suspended in the medium of pH 7.2, does not affect CRAC activity, while alkalisation of the extracellular milieu by NaOH results in a strong stimulation of calcium entry. Thus, the mitochondrial effect on CRAC is exclusively related to the extracellular pH. Coupled mitochondria are able to take up Ca(2+) accumulated in the close proximity of CRAC. This protects these channels against feedback inhibition exerted by high [Ca(2+)](c). We conclude that CRAC may exist in two conformations: inhibitable and not inhibitable by cytosolic Ca(2+). Lower extracellular pH promotes the former one. This explains a much higher inhibitory effect of mitochondrial uncouplers on the calcium influx into the cells exposed to pH 7.2 than that observed in the cells suspended in the medium of pH 7.8. This phenomenon may provide an additional mechanism protecting cells against calcium overloading in transient episodes of energy stress.
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Affiliation(s)
- Krzysztof Zablocki
- Nencki Institute of Experimental Biology, Pasteura 3, 02 093, Warsaw, Poland
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Abstract
Apoptosis is a form of programmed cell death important in the development and tissue homeostasis of multicellular organisms. Abnormalities in cell death control can lead to a variety of diseases, including cancer and degenerative disorders. Hence, the process of apoptosis is tightly regulated through multiple independent signalling pathways that are initiated either from triggering events within the cell or at the cell surface. In recent years, mitochondria have emerged as the central components of such apoptotic signalling pathways and are now known to control apoptosis through the release of apoptogenic proteins. In this review we aim to give an overview of the role of the mitochondria during apoptosis and the molecular mechanisms involved.
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Affiliation(s)
- P A Parone
- Departement de Biologie Cellulaire, University of Geneva, 30, quai E.-Ansermet, 1211 Geneva 4, Switzerland.
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