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Ben-Zichri S, Malishev R, Oren O, Bloch DN, Taube R, Papo N, Jelinek R. Bcl-2-Homology-Only Proapoptotic Peptides Modulate β-Amyloid Aggregation and Toxicity. ACS Chem Neurosci 2021; 12:4554-4563. [PMID: 34806861 DOI: 10.1021/acschemneuro.1c00611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Aggregation of the β-Amyloid (Aβ) peptide in brain tissues is the hallmark of Alzheimer's disease (AD). While Aβ is presumed to be insidiously involved in the disease's pathophysiology, concrete mechanisms accounting for the role of Aβ in AD are yet to be deciphered. While Aβ has been primarily identified in the extracellular space, the peptide also accumulates in cellular compartments such as mitochondria and lysosomes and impairs cellular functions. Here, we show that prominent proapoptotic peptides associated with the mitochondrial outer membrane, the Bcl-2-homology-only peptides BID, PUMA, and NOXA, exert significant and divergent effects upon aggregation, cytotoxicity, and membrane interactions of Aβ42, the main Aβ homolog. Interestingly, we show that BID and PUMA accelerated aggregation of Aβ42, reduced Aβ42-induced toxicity and mitochondrial disfunction, and inhibited Aβ42-membrane interactions. In contrast, NOXA exhibited opposite effects, reducing Aβ42 fibril formation, affecting more pronounced apoptotic effects and mitochondrial disfunction, and enhancing membrane interactions of Aβ42. The effects of BID, PUMA, and NOXA upon the Aβ42 structure and toxicity may be linked to its biological properties and affect pathophysiological features of AD.
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Affiliation(s)
- Shani Ben-Zichri
- Department of Chemistry and Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Ravit Malishev
- Department of Chemistry and Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Ofek Oren
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Daniel N. Bloch
- Department of Chemistry and Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Ran Taube
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Niv Papo
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering and the National Institute of Biotechnology, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Raz Jelinek
- Department of Chemistry and Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
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2
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Luff SA, Kao CY, Papoutsakis ET. Role of p53 and transcription-independent p53-induced apoptosis in shear-stimulated megakaryocytic maturation, particle generation, and platelet biogenesis. PLoS One 2018; 13:e0203991. [PMID: 30231080 PMCID: PMC6145578 DOI: 10.1371/journal.pone.0203991] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/02/2018] [Indexed: 12/18/2022] Open
Abstract
Megakaryocytes (Mks) derive from hematopoietic stem and progenitor cells (HSPCs) in the bone marrow and develop into large, polyploid cells that eventually give rise to platelets. As Mks mature, they migrate from the bone marrow niche into the vasculature, where they are exposed to shear forces from blood flow, releasing Mk particles (platelet-like particles (PLPs), pro/preplatelets (PPTs), and Mk microparticles (MkMPs)) into circulation. We have previously shown that transcription factor p53 is important in Mk maturation, and that physiological levels of shear promote Mk particle generation and platelet biogenesis. Here we examine the role of p53 in the Mk shear-stress response. We show that p53 is acetylated in response to shear in both immature and mature Mks, and that decreased expression of deacetylase HDAC1, and increased expression of the acetyltransferases p300 and PCAF might be responsible for these changes. We also examined the hypothesis that p53 might be involved in the shear-induced Caspase 3 activation, phosphatidylserine (PS) externalization, and increased biogenesis of PLPs, PPTs, and MkMPs. We show that p53 is involved in all these shear-induced processes. We show that in response to shear, acetyl-p53 binds Bax, cytochrome c is released from mitochondria, and Caspase 9 is activated. We also show that shear-stimulated Caspase 9 activation and Mk particle biogenesis depend on transcription-independent p53-induced apoptosis (TIPA), but PS externalization is not. This is the first report to show that shear flow stimulates TIPA and that Caspase 9 activation and Mk-particle biogenesis are directly modulated by TIPA.
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Affiliation(s)
- Stephanie A. Luff
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
| | - Chen-Yuan Kao
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, United States of America
| | - Eleftherios T. Papoutsakis
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States of America
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, United States of America
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3
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Jodeiri Farshbaf M, Kiani-Esfahani A. Succinate dehydrogenase: Prospect for neurodegenerative diseases. Mitochondrion 2017; 42:77-83. [PMID: 29225013 DOI: 10.1016/j.mito.2017.12.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 11/25/2017] [Accepted: 12/06/2017] [Indexed: 12/13/2022]
Abstract
Onset of Alzheimer's, Parkinson's and Huntington's diseases as neurodegenerative disorders is increased by age. Alleviation of clinical symptoms and protection of neurons against degeneration are the main aspects of researches to establish new therapeutic strategies. Many studies have shown that mitochondria play crucial roles in high energy demand tissues like brain. Impairments in mitochondrial activity and physiology can makes neurons vulnerable to stress and degeneration. Succinate dehydrogenase (SDH) connects tricarboxylic cycle to the electron transport chain. Therefore, dysfunction of the SDH could impair mitochondrial activity, ATP generation and energy hemostasis in the cell. Exceed lipid synthesis, induction of the excitotoxicity in neurodegenerative disorders could be controlled by SDH through direct and indirect mechanism. In addition, mutation in SDH correlates with the onset of neurodegenerative disorders. Therefore, SDH could behave as a key regulator in neuroprotection. This review will present recent findings which are about SDH activity and related pathways which could play important roles in neuronal survival. Additionally, we will discuss about all possibilities which candidate SDH as a neuroprotective agent.
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Affiliation(s)
| | - Abbas Kiani-Esfahani
- Department of Cellular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan 816513-1378, Iran
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Wang JC, Bindokas VP, Skinner M, Emrick T, Marks JD. Mitochondrial mechanisms of neuronal rescue by F-68, a hydrophilic Pluronic block co-polymer, following acute substrate deprivation. Neurochem Int 2017; 109:126-140. [PMID: 28433663 PMCID: PMC5641222 DOI: 10.1016/j.neuint.2017.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/29/2017] [Accepted: 04/10/2017] [Indexed: 01/09/2023]
Abstract
Global brain ischemia can lead to widespread neuronal death and poor neurologic outcomes in patients. Despite detailed understanding of the cellular and molecular mechanisms mediating neuronal death following focal and global brain hypoxia-ischemia, treatments to reduce ischemia-induced brain injury remain elusive. One pathway central to neuronal death following global brain ischemia is mitochondrial dysfunction, one consequence of which is the cascade of intracellular events leading to mitochondrial outer membrane permeabilization. A novel approach to rescuing injured neurons from death involves targeting cellular membranes using a class of synthetic molecules called Pluronics. Pluronics are triblock copolymers of hydrophilic poly[ethylene oxide] (PEO) and hydrophobic poly[propylene oxide] (PPO). Evidence is accumulating to suggest that hydrophilic Pluronics rescue injured neurons from death following substrate deprivation by preventing mitochondrial dysfunction. Here, we will review current understanding of the nature of interaction of Pluronic molecules with biological membranes and the efficacy of F-68, an 80% hydrophilic Pluronic, in rescuing neurons from injury. We will review data indicating that F-68 reduces mitochondrial dysfunction and mitochondria-dependent death pathways in a model of neuronal injury in vitro, and present new evidence that F-68 acts directly on mitochondria to inhibit mitochondrial outer membrane permeabilization. Finally, we will present results of a pilot, proof-of-principle study suggesting that F-68 is effective in reducing hippocampal injury induced by transient global ischemia in vivo. By targeting mitochondrial dysfunction, F-68 and other Pluronic molecules constitute an exciting new approach to rescuing neurons from acute injury.
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Affiliation(s)
- Janice C Wang
- Department of Pediatrics, University of Chicago, Chicago, IL, United States
| | - Vytautas P Bindokas
- Department of Pharmacological, Physiological Sciences, University of Chicago, IL, United States
| | - Matthew Skinner
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA, United States
| | - Todd Emrick
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA, United States
| | - Jeremy D Marks
- Department of Pediatrics, University of Chicago, Chicago, IL, United States; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, IL, United States.
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5
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Sarosiek KA, Fraser C, Muthalagu N, Bhola PD, Chang W, McBrayer SK, Cantlon A, Fisch S, Golomb-Mello G, Ryan JA, Deng J, Jian B, Corbett C, Goldenberg M, Madsen JR, Liao R, Walsh D, Sedivy J, Murphy DJ, Carrasco DR, Robinson S, Moslehi J, Letai A. Developmental Regulation of Mitochondrial Apoptosis by c-Myc Governs Age- and Tissue-Specific Sensitivity to Cancer Therapeutics. Cancer Cell 2017; 31:142-156. [PMID: 28017613 PMCID: PMC5363285 DOI: 10.1016/j.ccell.2016.11.011] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 09/13/2016] [Accepted: 11/17/2016] [Indexed: 01/20/2023]
Abstract
It is not understood why healthy tissues can exhibit varying levels of sensitivity to the same toxic stimuli. Using BH3 profiling, we find that mitochondria of many adult somatic tissues, including brain, heart, and kidneys, are profoundly refractory to pro-apoptotic signaling, leading to cellular resistance to cytotoxic chemotherapies and ionizing radiation. In contrast, mitochondria from these tissues in young mice and humans are primed for apoptosis, predisposing them to undergo cell death in response to genotoxic damage. While expression of the apoptotic protein machinery is nearly absent by adulthood, in young tissues its expression is driven by c-Myc, linking developmental growth to cell death. These differences may explain why pediatric cancer patients have a higher risk of developing treatment-associated toxicities.
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Affiliation(s)
- Kristopher A Sarosiek
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Mayer 430, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Cameron Fraser
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Mayer 430, Boston, MA 02115, USA
| | | | - Patrick D Bhola
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Mayer 430, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Weiting Chang
- Harvard Medical School, Boston, MA 02115, USA; Division of Genetics and Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Samuel K McBrayer
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Mayer 430, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Adam Cantlon
- Harvard Medical School, Boston, MA 02115, USA; Division of Genetics and Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Sudeshna Fisch
- Harvard Medical School, Boston, MA 02115, USA; Division of Genetics and Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Gail Golomb-Mello
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Jeremy A Ryan
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Mayer 430, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Jing Deng
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Mayer 430, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Brian Jian
- Department of Neurosurgery, Kaiser Permanente, Sacramento, CA 95815, USA
| | - Chris Corbett
- Department of Neurosurgery, Boston Children's Hospital, Boston, MA 02115, USA
| | - Marti Goldenberg
- Department of Neurosurgery, Boston Children's Hospital, Boston, MA 02115, USA
| | - Joseph R Madsen
- Harvard Medical School, Boston, MA 02115, USA; Department of Neurosurgery, Boston Children's Hospital, Boston, MA 02115, USA
| | - Ronglih Liao
- Harvard Medical School, Boston, MA 02115, USA; Division of Genetics and Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Dominic Walsh
- Harvard Medical School, Boston, MA 02115, USA; Division of Genetics and Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - John Sedivy
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Daniel J Murphy
- Cancer Research UK Beatson Institute, Glasgow G61 1BD, Scotland; Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1BD, Scotland
| | - Daniel Ruben Carrasco
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Mayer 430, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Shenandoah Robinson
- Harvard Medical School, Boston, MA 02115, USA; Department of Neurosurgery, Boston Children's Hospital, Boston, MA 02115, USA
| | - Javid Moslehi
- Division of Cardiovascular Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Division of Hematology-Oncology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Cardio-Oncology Program, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Anthony Letai
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Mayer 430, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA.
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6
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Requejo-Aguilar R, Bolaños JP. Mitochondrial control of cell bioenergetics in Parkinson's disease. Free Radic Biol Med 2016; 100:123-137. [PMID: 27091692 PMCID: PMC5065935 DOI: 10.1016/j.freeradbiomed.2016.04.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/13/2016] [Accepted: 04/14/2016] [Indexed: 12/15/2022]
Abstract
Parkinson disease (PD) is a neurodegenerative disorder characterized by a selective loss of dopaminergic neurons in the substantia nigra. The earliest biochemical signs of the disease involve failure in mitochondrial-endoplasmic reticulum cross talk and lysosomal function, mitochondrial electron chain impairment, mitochondrial dynamics alterations, and calcium and iron homeostasis abnormalities. These changes are associated with increased mitochondrial reactive oxygen species (mROS) and energy deficiency. Recently, it has been reported that, as an attempt to compensate for the mitochondrial dysfunction, neurons invoke glycolysis as a low-efficient mode of energy production in models of PD. Here, we review how mitochondria orchestrate the maintenance of cellular energetic status in PD, with special focus on the switch from oxidative phosphorylation to glycolysis, as well as the implication of endoplasmic reticulum and lysosomes in the control of bioenergetics.
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Affiliation(s)
- Raquel Requejo-Aguilar
- Department of Biochemistry and Molecular Biology, University of Cordoba, Institute Maimonides of Biomedical Investigation of Cordoba (IMIBIC), Cordoba, Spain
| | - Juan P Bolaños
- Institute of Functional Biology and Genomics (IBFG), University of Salamanca-CSIC, Zacarias Gonzalez, 2, 37007 Salamanca, Spain.
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7
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Barho MT, Oppermann S, Schrader FC, Degenhardt I, Elsässer K, Wegscheid-Gerlach C, Culmsee C, Schlitzer M. N-Acyl Derivatives of 4-Phenoxyaniline as Neuroprotective Agents. ChemMedChem 2014; 9:2260-73. [DOI: 10.1002/cmdc.201402195] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Indexed: 12/18/2022]
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8
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Oppermann S, Schrader FC, Elsässer K, Dolga AM, Kraus AL, Doti N, Wegscheid-Gerlach C, Schlitzer M, Culmsee C. Novel N-phenyl-substituted thiazolidinediones protect neural cells against glutamate- and tBid-induced toxicity. J Pharmacol Exp Ther 2014; 350:273-89. [PMID: 24849923 DOI: 10.1124/jpet.114.213777] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial demise is a key feature of progressive neuronal death contributing to acute and chronic neurological disorders. Recent studies identified a pivotal role for the BH3-only protein B-cell lymphoma-2 interacting domain death antagonist (Bid) for such mitochondrial damage and delayed neuronal death after oxygen-glucose deprivation, glutamate-induced excitotoxicity, or oxidative stress in vitro and after cerebral ischemia in vivo. Therefore, we developed new N-phenyl-substituted thiazolidine-2,4-dione derivatives as potent inhibitors of Bid-dependent neurotoxicity. The new compounds 6, 7, and 16 were identified as highly protective by extensive screening in a model of glutamate toxicity in immortalized mouse hippocampal neurons (HT-22 cells). These compounds significantly prevent truncated Bid-induced toxicity in the neuronal cell line, providing strong evidence that inhibition of Bid was the underlying mechanism of the observed protective effects. Furthermore, Bid-dependent hallmarks of mitochondrial dysfunction, such as loss of mitochondrial membrane potential, ATP depletion, as well as impairments in mitochondrial respiration, are significantly prevented by compounds 6, 7, and 16. Therefore, the present study identifies a class of N-phenyl thiazolidinediones as novel Bid-inhibiting neuroprotective agents that provide promising therapeutic perspectives for neurodegenerative diseases, in which Bid-mediated mitochondrial damage and associated intrinsic death pathways contribute to the underlying progressive loss of neurons.
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Affiliation(s)
- Sina Oppermann
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
| | - Florian C Schrader
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
| | - Katharina Elsässer
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
| | - Amalia M Dolga
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
| | - Anna Lena Kraus
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
| | - Nunzianna Doti
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
| | - Christof Wegscheid-Gerlach
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
| | - Martin Schlitzer
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
| | - Carsten Culmsee
- Institute for Pharmacology and Clinical Pharmacy, Faculty of Pharmacy (S.O., K.E., A.M.D., C.C.) and Institute for Pharmaceutical Chemistry, Faculty of Pharmacy, Philipps University of Marburg, Marburg, Germany (F.C.S., A.L.K., C.W.-G., M.S.); and Institute of Biostructures and Bioimaging, Naples, Italy (N.D.)
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9
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Calì T, Ottolini D, Brini M. Calcium and Endoplasmic Reticulum-Mitochondria Tethering in Neurodegeneration. DNA Cell Biol 2013; 32:140-6. [DOI: 10.1089/dna.2013.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Tito Calì
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
| | - Denis Ottolini
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
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10
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Shoshan-Barmatz V, Mizrachi D. VDAC1: from structure to cancer therapy. Front Oncol 2012; 2:164. [PMID: 23233904 PMCID: PMC3516065 DOI: 10.3389/fonc.2012.00164] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 10/24/2012] [Indexed: 12/14/2022] Open
Abstract
Here, we review current evidence pointing to the function of VDAC1 in cell life and death, and highlight these functions in relation to cancer. Found at the outer mitochondrial membrane, VDAC1 assumes a crucial position in the cell, controlling the metabolic cross-talk between mitochondria and the rest of the cell. Moreover, its location at the boundary between the mitochondria and the cytosol enables VDAC1 to interact with proteins that mediate and regulate the integration of mitochondrial functions with other cellular activities. As a metabolite transporter, VDAC1 contributes to the metabolic phenotype of cancer cells. This is reflected by VDAC1 over-expression in many cancer types, and by inhibition of tumor development upon silencing VDAC1 expression. Along with regulating cellular energy production and metabolism, VDAC1 is also a key protein in mitochondria-mediated apoptosis, participating in the release of apoptotic proteins and interacting with anti-apoptotic proteins. The involvement of VDAC1 in the release of apoptotic proteins located in the inter-membranal space is discussed, as is VDAC1 oligomerization as an important step in apoptosis induction. VDAC also serves as an anchor point for mitochondria-interacting proteins, some of which are also highly expressed in many cancers, such as hexokinase (HK), Bcl2, and Bcl-xL. By binding to VDAC, HK provides both metabolic benefit and apoptosis-suppressive capacity that offers the cell a proliferative advantage and increases its resistance to chemotherapy. VDAC1-based peptides that bind specifically to HK, Bcl2, or Bcl-xL abolished the cell’s abilities to bypass the apoptotic pathway. Moreover, these peptides promote cell death in a panel of genetically characterized cell lines derived from different human cancers. These and other functions point to VDAC1 as a rational target for the development of a new generation of therapeutics.
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Affiliation(s)
- Varda Shoshan-Barmatz
- Department of Life Sciences, Ben-Gurion University of the Negev Beer-Sheva, Israel ; The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev Beer-Sheva, Israel
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11
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Bax activation initiates the assembly of a multimeric catalyst that facilitates Bax pore formation in mitochondrial outer membranes. PLoS Biol 2012; 10:e1001394. [PMID: 23049480 PMCID: PMC3457932 DOI: 10.1371/journal.pbio.1001394] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 08/15/2012] [Indexed: 11/19/2022] Open
Abstract
Bax/Bak-mediated mitochondrial outer membrane permeabilization (MOMP) is essential for "intrinsic" apoptotic cell death. Published studies used synthetic liposomes to reveal an intrinsic pore-forming activity of Bax, but it is unclear how other mitochondrial outer membrane (MOM) proteins might facilitate this function. We carefully analyzed the kinetics of Bax-mediated pore formation in isolated MOMs, with some unexpected results. Native MOMs were more sensitive than liposomes to added Bax, and MOMs displayed a lag phase not observed with liposomes. Heat-labile MOM proteins were required for this enhanced response. A two-tiered mathematical model closely fit the kinetic data: first, Bax activation promotes the assembly of a multimeric complex, which then catalyzes the second reaction, Bax-dependent pore formation. Bax insertion occurred immediately upon Bax addition, prior to the end of the lag phase. Permeabilization kinetics were affected in a reciprocal manner by [cBid] and [Bax], confirming the "hit-and-run" hypothesis of cBid-induced direct Bax activation. Surprisingly, MOMP rate constants were linearly related to [Bax], implying that Bax acts non-cooperatively. Thus, the oligomeric catalyst is distinct from Bax. Moreover, contrary to common assumption, pore formation kinetics depend on Bax monomers, not oligomers. Catalyst formation exhibited a sharp transition in activation energy at ∼28°C, suggesting a role for membrane lipid packing. Furthermore, catalyst formation was strongly inhibited by chemical antagonists of the yeast mitochondrial fission protein, Dnm1. However, the mammalian ortholog, Drp1, was undetectable in mitochondrial outer membranes. Moreover, ATP and GTP were dispensable for MOMP. Thus, the data argue that oligomerization of a catalyst protein, distinct from Bax and Drp1, facilitates MOMP, possibly through a membrane-remodeling event.
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12
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Calì T, Ottolini D, Brini M. Mitochondrial Ca(2+) and neurodegeneration. Cell Calcium 2012; 52:73-85. [PMID: 22608276 PMCID: PMC3396847 DOI: 10.1016/j.ceca.2012.04.015] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 04/18/2012] [Accepted: 04/20/2012] [Indexed: 12/16/2022]
Abstract
Mitochondria are essential for ensuring numerous fundamental physiological processes such as cellular energy, redox balance, modulation of Ca2+ signaling and important biosynthetic pathways. They also govern the cell fate by participating in the apoptosis pathway. The mitochondrial shape, volume, number and distribution within the cells are strictly controlled. The regulation of these parameters has an impact on mitochondrial function, especially in the central nervous system, where trafficking of mitochondria is critical to their strategic intracellular distribution, presumably according to local energy demands. Thus, the maintenance of a healthy mitochondrial population is essential to avoid the impairment of the processes they regulate: for this purpose, cells have developed mechanisms involving a complex system of quality control to remove damaged mitochondria, or to renew them. Defects of these processes impair mitochondrial function and lead to disordered cell function, i.e., to a disease condition. Given the standard role of mitochondria in all cells, it might be expected that their dysfunction would give rise to similar defects in all tissues. However, damaged mitochondrial function has pleiotropic effects in multicellular organisms, resulting in diverse pathological conditions, ranging from cardiac and brain ischemia, to skeletal muscle myopathies to neurodegenerative diseases. In this review, we will focus on the relationship between mitochondrial (and cellular) derangements and Ca2+ dysregulation in neurodegenerative diseases, emphasizing the evidence obtained in genetic models. Common patterns, that recognize the derangement of Ca2+ and energy control as a causative factor, have been identified: advances in the understanding of the molecular regulation of Ca2+ homeostasis, and on the ways in which it could become perturbed in neurological disorders, may lead to the development of therapeutic strategies that modulate neuronal Ca2+ signaling.
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Affiliation(s)
- Tito Calì
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
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13
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Kerrigan TL, Daniel J W, Regan PL, Cho K. The role of neuronal calcium sensors in balancing synaptic plasticity and synaptic dysfunction. Front Mol Neurosci 2012; 5:57. [PMID: 22586365 PMCID: PMC3343381 DOI: 10.3389/fnmol.2012.00057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 03/07/2012] [Indexed: 11/13/2022] Open
Abstract
Neuronal calcium sensors (NCS) readily bind calcium and undergo conformational changes enabling them to interact and regulate specific target molecules. These interactions lead to dynamic alterations in protein trafficking that significantly impact upon synaptic function. Emerging evidence suggests that NCS and alterations in Ca(2+) mobilization modulate glutamate receptor trafficking, subsequently determining the expression of different forms of synaptic plasticity. In this review, we aim to discuss the functional relevance of NCS in protein trafficking and their emerging role in synaptic plasticity. Their significance within the concept of "translational neuroscience" will also be highlighted, by assessing their potential as key molecules in neurodegeneration.
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Affiliation(s)
- Talitha L Kerrigan
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, School of Clinical Sciences, Faculty of Medicine and Dentistry, University of Bristol, Bristol, UK
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14
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Kim WS, Park JY, Kim TK, Baik SW. The changes of mitochondrial cytochrome c and GABAergic neuron in neuropathic pain model. Korean J Anesthesiol 2012; 62:365-70. [PMID: 22558504 PMCID: PMC3337384 DOI: 10.4097/kjae.2012.62.4.365] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/21/2012] [Accepted: 01/25/2012] [Indexed: 12/19/2022] Open
Abstract
Background Role of cytochrome c (Cyt c) is an apoptogenic agent under certain conditions. The mitochondrial permeability transition pore (MPTP) plays an important role in cell death since it opens, leading to mitochondrial swelling and release of Cyt c, which initiates apoptosis. By inhibiting the opening of MPTP, cyclosporine A (CSA) may contribute to maintaining mitochondrial homeostasis. We investigate the effects of the partial sciatic nerve injury (PSNI)-induced neuropathic pain model on mitochondrial Cyt c release and the effects of CSA on neuroprotection by mitochondrial stabilizing activity in PSNI rats. Methods Rats were assigned to two groups that received different operations (Group P; PSNI operation, Group S; sham operation). The changes of cyt c and GABAergic neuron were evaluated in the spinal cord tissue. After which, PSNI rats randomly received CSA (Group C) or saline (Group S), and the changes of mechanical thresholds with Cyt c and GABAergic neuron were checked. Results PSNI in rats increased the release of cytosolic Cyt c. However, GABAergic cells were not decreased in the spinal cord level on the ipsilateral side to the PSNI. The second experiment reveal a reduction in Cyt c release, using CSA in PSNI model. Rats receiving CSA were afforded the antiallodynia without decrease of GABAergic cell. Conclusions The Cyt c probably contributes to nerve dysfunction after PSNI. PSNI induced neuropathic pain was profoundly linked to mitochondrial stabilization. Thus, the potent neuroprotector, CSA, might produce antiallodynia through its capability to inhibit the opening of MPTP.
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Affiliation(s)
- Won Sung Kim
- Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Busan, Korea
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15
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Brustovetsky T, Li T, Yang Y, Zhang JT, Antonsson B, Brustovetsky N. BAX insertion, oligomerization, and outer membrane permeabilization in brain mitochondria: role of permeability transition and SH-redox regulation. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1797:1795-806. [PMID: 20655869 PMCID: PMC2933961 DOI: 10.1016/j.bbabio.2010.07.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 07/05/2010] [Accepted: 07/11/2010] [Indexed: 10/19/2022]
Abstract
BAX cooperates with truncated BID (tBID) and Ca(2+) in permeabilizing the outer mitochondrial membrane (OMM) and releasing mitochondrial apoptogenic proteins. The mechanisms of this cooperation are still unclear. Here we show that in isolated brain mitochondria, recombinant BAX readily self-integrates/oligomerizes in the OMM but produces only a minuscule release of cytochrome c, indicating that BAX insertion/oligomerization in the OMM does not always lead to massive OMM permeabilization. Ca(2+) in a mitochondrial permeability transition (mPT)-dependent and recombinant tBID in an mPT-independent manner promoted BAX insertion/ oligomerization in the OMM and augmented cytochrome c release. Neither tBID nor Ca(2+) induced BAX oligomerization in the solution without mitochondria, suggesting that BAX oligomerization required interaction with the organelles and followed rather than preceded BAX insertion in the OMM. Recombinant Bcl-xL failed to prevent BAX insertion/oligomerization in the OMM but strongly attenuated cytochrome c release. On the other hand, a reducing agent, dithiothreitol (DTT), inhibited BAX insertion/oligomerization augmented by tBID or Ca(2+) and suppressed the BAX-mediated release of cytochrome c and Smac/DIABLO but failed to inhibit Ca(2+)-induced swelling. Altogether, these data suggest that in brain mitochondria, BAX insertion/oligomerization can be dissociated from OMM permeabilization and that tBID and Ca(2+) stimulate BAX insertion/oligomerization and BAX-mediated OMM permeabilization by different mechanisms involving mPT induction and modulation of the SH-redox state.
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Affiliation(s)
- Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Tsyregma Li
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Youyun Yang
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
- Simon Cancer Center, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Jiang-Ting Zhang
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
- Simon Cancer Center, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | | | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis IN 46202, USA
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16
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VDAC, a multi-functional mitochondrial protein regulating cell life and death. Mol Aspects Med 2010; 31:227-85. [PMID: 20346371 DOI: 10.1016/j.mam.2010.03.002] [Citation(s) in RCA: 530] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 03/17/2010] [Indexed: 01/22/2023]
Abstract
Research over the past decade has extended the prevailing view of the mitochondrion to include functions well beyond the generation of cellular energy. It is now recognized that mitochondria play a crucial role in cell signaling events, inter-organellar communication, aging, cell proliferation, diseases and cell death. Thus, mitochondria play a central role in the regulation of apoptosis (programmed cell death) and serve as the venue for cellular decisions leading to cell life or death. One of the mitochondrial proteins controlling cell life and death is the voltage-dependent anion channel (VDAC), also known as mitochondrial porin. VDAC, located in the mitochondrial outer membrane, functions as gatekeeper for the entry and exit of mitochondrial metabolites, thereby controlling cross-talk between mitochondria and the rest of the cell. VDAC is also a key player in mitochondria-mediated apoptosis. Thus, in addition to regulating the metabolic and energetic functions of mitochondria, VDAC appears to be a convergence point for a variety of cell survival and cell death signals mediated by its association with various ligands and proteins. In this article, we review what is known about the VDAC channel in terms of its structure, relevance to ATP rationing, Ca(2+) homeostasis, protection against oxidative stress, regulation of apoptosis, involvement in several diseases and its role in the action of different drugs. In light of our recent findings and the recently solved NMR- and crystallography-based 3D structures of VDAC1, the focus of this review will be on the central role of VDAC in cell life and death, addressing VDAC function in the regulation of mitochondria-mediated apoptosis with an emphasis on structure-function relations. Understanding structure-function relationships of VDAC is critical for deciphering how this channel can perform such a variety of functions, all important for cell life and death. This review also provides insight into the potential of VDAC1 as a rational target for new therapeutics.
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17
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Szigeti A, Hocsak E, Rapolti E, Racz B, Boronkai A, Pozsgai E, Debreceni B, Bognar Z, Bellyei S, Sumegi B, Gallyas F. Facilitation of mitochondrial outer and inner membrane permeabilization and cell death in oxidative stress by a novel Bcl-2 homology 3 domain protein. J Biol Chem 2010; 285:2140-51. [PMID: 19901022 PMCID: PMC2804370 DOI: 10.1074/jbc.m109.015222] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 11/01/2009] [Indexed: 11/06/2022] Open
Abstract
We identified a sequence homologous to the Bcl-2 homology 3 (BH3) domain of Bcl-2 proteins in SOUL. Tissues expressed the protein to different extents. It was predominantly located in the cytoplasm, although a fraction of SOUL was associated with the mitochondria that increased upon oxidative stress. Recombinant SOUL protein facilitated mitochondrial permeability transition and collapse of mitochondrial membrane potential (MMP) and facilitated the release of proapoptotic mitochondrial intermembrane proteins (PMIP) at low calcium and phosphate concentrations in a cyclosporine A-dependent manner in vitro in isolated mitochondria. Suppression of endogenous SOUL by diced small interfering RNA in HeLa cells increased their viability in oxidative stress. Overexpression of SOUL in NIH3T3 cells promoted hydrogen peroxide-induced cell death and stimulated the release of PMIP but did not enhance caspase-3 activation. Despite the release of PMIP, SOUL facilitated predominantly necrotic cell death, as revealed by annexin V and propidium iodide staining. This necrotic death could be the result of SOUL-facilitated collapse of MMP demonstrated by JC-1 fluorescence. Deletion of the putative BH3 domain sequence prevented all of these effects of SOUL. Suppression of cyclophilin D prevented these effects too, indicating that SOUL facilitated mitochondrial permeability transition in vivo. Overexpression of Bcl-2 and Bcl-x(L), which can counteract the mitochondria-permeabilizing effect of BH3 domain proteins, also prevented SOUL-facilitated collapse of MMP and cell death. These data indicate that SOUL can be a novel member of the BH3 domain-only proteins that cannot induce cell death alone but can facilitate both outer and inner mitochondrial membrane permeabilization and predominantly necrotic cell death in oxidative stress.
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Affiliation(s)
- Andras Szigeti
- From the Institute of Oncotherapy and
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Eniko Hocsak
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Edit Rapolti
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Boglarka Racz
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Arpad Boronkai
- From the Institute of Oncotherapy and
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Eva Pozsgai
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Balazs Debreceni
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Zita Bognar
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Szabolcs Bellyei
- From the Institute of Oncotherapy and
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Balazs Sumegi
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
| | - Ferenc Gallyas
- Department of Biochemistry and Medical Chemistry, University of Pécs, 12 Szigeti Street, Pécs H-7624, Hungary
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Peixoto PM, Ryu SY, Pruzansky DP, Kuriakose M, Gilmore A, Kinnally KW. Mitochondrial apoptosis is amplified through gap junctions. Biochem Biophys Res Commun 2009; 390:38-43. [PMID: 19766591 DOI: 10.1016/j.bbrc.2009.09.054] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 09/15/2009] [Indexed: 10/20/2022]
Abstract
The death of one cell can precipitate the death of nearby cells in a process referred to as the bystander effect. We investigated whether mitochondrial apoptosis generated a bystander effect and, if so, by which pathway. Microinjection with cytochrome c mimicked function of the mitochondrial apoptosis-induced channel MAC and caused apoptosis of both target and nearby osteoblasts. This effect was suppressed by inhibiting gap junction intercellular communication. A bystander effect was also observed after exogenous expression of tBid, which facilitates MAC formation and cytochrome c release. Interestingly, in connexin-43 deficient osteoblasts, microinjection of cytochrome c induced apoptosis only in the target cell. These findings indicate that a death signal was generated downstream of MAC function and was transmitted through gap junctions to amplify apoptosis in neighboring cells. This concept may have implications in development of new therapeutic approaches.
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Affiliation(s)
- Pablo M Peixoto
- Dept Basic Sciences, New York University College of Dentistry, New York, NY 10010, USA
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19
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Dissimilar mechanisms of cytochrome c release induced by octyl glucoside-activated BAX and by BAX activated with truncated BID. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:52-62. [PMID: 19664589 DOI: 10.1016/j.bbabio.2009.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 07/20/2009] [Accepted: 07/27/2009] [Indexed: 11/21/2022]
Abstract
In the present study, we compared alkali-resistant BAX insertion into the outer mitochondrial membrane, mitochondrial remodeling, mitochondrial membrane potential changes, and cytochrome c (Cyt c) release from isolated brain mitochondria triggered by recombinant BAX oligomerized with 1% octyl glucoside (BAX(oligo)) and by a combination of monomeric BAX (BAX(mono)) and caspase 8-cleaved C-terminal fragment of recombinant BID (truncated BID, t(c)BID). We also examined whether the effects induced by BAX(oligo) or by BAX(mono) activated with t(c)BID depended on induction of the mitochondrial permeability transition. The results obtained in this study revealed that t(c)BID plus BAX(mono) produced BAX insertion and Cyt c release without overt changes in mitochondrial morphology. On the contrary, treatment of mitochondria with BAX(oligo) resulted in BAX insertion and Cyt c release, which were accompanied by gross distortion of mitochondrial morphology. The effects of BAX(oligo) could be at least partially suppressed by mitochondrial depolarization. The effects of t(c)BID plus BAX(mono) were insensitive to depolarization. BAX(oligo) produced similar BAX insertion, mitochondrial remodeling, and Cyt c release in KCl- and in N-methyl-D-glucamine-based incubation media indicating a non-essential role for K+ influx into mitochondria in these processes. A combination of cyclosporin A and ADP, inhibitors of the mitochondrial permeability transition, attenuated Cyt c release, mitochondrial remodeling, and depolarization induced by BAX(oligo), but failed to influence the effects produced by t(c)BID plus BAX(mono). Thus, our results suggest a significant difference in the mechanisms of the outer mitochondrial membrane permeabilization and Cyt c release induced by detergent-oligomerized BAX(oligo) and by BAX activated with t(c)BID.
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20
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Oppenheim MLS, Hargreaves IP, Pope S, Land JM, Heales SJR. Mitochondrial cytochrome c release: a factor to consider in mitochondrial disease? J Inherit Metab Dis 2009; 32:269-73. [PMID: 19169843 DOI: 10.1007/s10545-009-1061-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 12/19/2008] [Accepted: 12/22/2008] [Indexed: 10/21/2022]
Abstract
The pathogenesis of mitochondrial disorders has largely focused on the impairment of cellular energy metabolism. However, mitochondrial dysfunction has also been implicated as a factor in the initiation of apoptosis due to the translocation of cytochrome c, from mitochondria to the cytosol, and the subsequent cleavage of pro-caspase 3. In this study, we determined the cytochrome c content of cytosols (skeletal muscle) prepared from 22 patients with evidence of compromised mitochondrial electron transport chain enzyme activity and 26 disease controls. The cytochrome c content of the mitochondrial electron transport chain-deficient group was found to be significantly (p < 0.02) elevated when compared with the control group (63.7 +/- 15.5 versus 27.7 +/- 2.5 ng/mg protein). Furthermore, a relationship between the cytosolic cytochrome c content of skeletal muscle and complex I and complex IV activities was demonstrated. Such data raise the possibility that mitochondrial cytochrome c release may be a feature of mitochondrial disorders, particularly for those patients with marked deficiencies of respiratory chain enzymes. Whether initiation of apoptosis occurs as a direct consequence of this cytochrome c release has not been fully evaluated here. However, for one patient with the greatest documented cytosolic cytochrome c content, caspase 3 could be demonstrated in the cytosolic preparation. Further work is required in order to establish whether a relationship also exists between caspase 3 formation and the magnitude of respiratory chain deficiency.
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Affiliation(s)
- M L S Oppenheim
- Neurometabolic Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
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21
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Li T, Brustovetsky T, Antonsson B, Brustovetsky N. Oligomeric BAX induces mitochondrial permeability transition and complete cytochrome c release without oxidative stress. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1777:1409-21. [PMID: 18771651 PMCID: PMC2613194 DOI: 10.1016/j.bbabio.2008.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 08/07/2008] [Accepted: 08/08/2008] [Indexed: 01/26/2023]
Abstract
In the present study, we investigated the mechanism of cytochrome c release from isolated brain mitochondria induced by recombinant oligomeric BAX (BAX(oligo)). We found that BAX(oligo) caused a complete release of cytochrome c in a concentration- and time-dependent manner. The release was similar to those induced by alamethicin, which causes maximal mitochondrial swelling and eliminates barrier properties of the OMM. BAX(oligo) also produced large amplitude mitochondrial swelling as judged by light scattering assay and transmission electron microscopy. In addition, BAX(oligo) resulted in a strong mitochondrial depolarization. ATP or a combination of cyclosporin A and ADP, inhibitors of the mPT, suppressed BAX(oligo)-induced mitochondrial swelling and depolarization as well as cytochrome c release but did not influence BAX(oligo) insertion into the OMM. Both BAX(oligo)- and alamethicin-induced cytochrome c releases were accompanied by inhibition of ROS generation, which was assessed by measuring mitochondrial H(2)O(2) release with an Amplex Red assay. The mPT inhibitors antagonized suppression of ROS generation caused by BAX(oligo) but not by alamethicin. Thus, BAX(oligo) resulted in a complete cytochrome c release from isolated brain mitochondria in the mPT-dependent manner without involvement of oxidative stress by the mechanism requiring mitochondrial remodeling and permeabilization of the OMM.
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Affiliation(s)
- Tsyregma Li
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Bruno Antonsson
- Geneva Research Center, Merck Serono International, Geneva, Switzerland
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis IN 46202, USA
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22
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Hiller S, Garces RG, Malia TJ, Orekhov VY, Colombini M, Wagner G. Solution structure of the integral human membrane protein VDAC-1 in detergent micelles. Science 2008; 321:1206-10. [PMID: 18755977 DOI: 10.1126/science.1161302] [Citation(s) in RCA: 529] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The voltage-dependent anion channel (VDAC) mediates trafficking of small molecules and ions across the eukaryotic outer mitochondrial membrane. VDAC also interacts with antiapoptotic proteins from the Bcl-2 family, and this interaction inhibits release of apoptogenic proteins from the mitochondrion. We present the nuclear magnetic resonance (NMR) solution structure of recombinant human VDAC-1 reconstituted in detergent micelles. It forms a 19-stranded beta barrel with the first and last strand parallel. The hydrophobic outside perimeter of the barrel is covered by detergent molecules in a beltlike fashion. In the presence of cholesterol, recombinant VDAC-1 can form voltage-gated channels in phospholipid bilayers similar to those of the native protein. NMR measurements revealed the binding sites of VDAC-1 for the Bcl-2 protein Bcl-x(L), for reduced beta-nicotinamide adenine dinucleotide, and for cholesterol. Bcl-x(L) interacts with the VDAC barrel laterally at strands 17 and 18.
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Affiliation(s)
- Sebastian Hiller
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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23
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Marí M, Colell A, Morales A, Caballero F, Moles A, Fernández A, Terrones O, Basañez G, Antonsson B, García-Ruiz C, Fernández-Checa JC. Mechanism of mitochondrial glutathione-dependent hepatocellular susceptibility to TNF despite NF-kappaB activation. Gastroenterology 2008; 134:1507-20. [PMID: 18343380 DOI: 10.1053/j.gastro.2008.01.073] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2007] [Accepted: 01/18/2008] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIMS Nuclear factor kappaB (NF-kappaB) is the master regulator of tumor necrosis factor (TNF) susceptibility. Although mitochondrial glutathione (mGSH) depletion was shown to sensitize hepatocytes to TNF despite NF-kappaB activation, the mechanisms involved, particularly the role of Bax oligomerization and mitochondrial outer membrane (MOM) permeabilization, 2 critical steps in cell death, remained unexplored. METHODS TNF signaling at the premitochondrial and mitochondrial levels was analyzed in primary mouse hepatocytes with or without mGSH depletion. RESULTS Unexpectedly, we observed that TNF activates caspase-8 independently of NF-kappaB inactivation, causing Bid cleavage and mitochondrial Bax oligomerization. However, their predicted consequences on MOM permeabilization, cytochrome c release, caspase-3 activation, and hepatocellular death occurred only on mGSH depletion. These events were preceded by stimulated mitochondrial reactive oxygen species that predominantly oxidized cardiolipin, changes not observed in acidic sphingomyelinase (ASMase)(-/-) hepatocytes. Oxidized cardiolipin potentiated oligomerized Bax-induced MOM-like liposome permeabilization by restructuring the lipid bilayer, without effect on membrane Bax insertion or oligomerization. ASMase(-/-) mice with mGSH depletion by cholesterol loading were resistant to TNF-induced liver injury in vivo. CONCLUSIONS Thus, MOM-localized oligomeric Bax is not sufficient for TNF-induced MOM permeabilization and cell death requiring mGSH-controlled ASMase-mediated mitochondrial membrane remodeling by oxidized cardiolipin generation.
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Affiliation(s)
- Montserrat Marí
- Liver Unit and Centro de Investigaciones Biomédicas Esther Koplowitz, IMDiM, Hospital Clínic i Provincial, and CIBEREHD, IDIBAPS, Barcelona, Spain
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Shalbuyeva N, Brustovetsky T, Brustovetsky N. Lithium desensitizes brain mitochondria to calcium, antagonizes permeability transition, and diminishes cytochrome C release. J Biol Chem 2007; 282:18057-18068. [PMID: 17485418 DOI: 10.1074/jbc.m702134200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Among the numerous effects of lithium on intracellular targets, its possible action on mitochondria remains poorly explored. In the experiments with suspension of isolated brain mitochondria, replacement of KCl by LiCl suppressed mitochondrial swelling, depolarization, and a release of cytochrome c induced by a single Ca2+ bolus. Li+ robustly protected individual brain mitochondria loaded with rhodamine 123 against Ca2+-induced depolarization. In the experiments with slow calcium infusion, replacement of KCl by LiCl in the incubation medium increased resilience of synaptic and nonsynaptic brain mitochondria as well as resilience of liver and heart mitochondria to the deleterious effect of Ca2+. In LiCl medium, mitochondria accumulated larger amounts of Ca2+ before they lost the ability to sequester Ca2+. However, lithium appeared to be ineffective if mitochondria were challenged by Sr2+ instead of Ca2+. Cyclosporin A, sanglifehrin A, and Mg2+, inhibitors of the mitochondrial permeability transition (mPT), increased mitochondrial Ca2+ capacity in KCl medium but failed to do so in LiCl medium. This suggests that the mPT might be a common target for Li+ and mPT inhibitors. In addition, lithium protected mitochondria against high Ca2+ in the presence of ATP, where cyclosporin A was reported to be ineffective. SB216763 and SB415286, inhibitors of glycogen synthase kinase-3beta, which is implicated in regulating reactive oxygen species-induced mPT in cardiac mitochondria, did not increase Ca2+ capacity of brain mitochondria. Altogether, these findings suggest that Li+ desensitizes mitochondria to elevated Ca2+ and diminishes cytochrome c release from brain mitochondria by antagonizing the Ca2+-induced mPT.
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Affiliation(s)
- Natalia Shalbuyeva
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202.
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Ryter SW, Kim HP, Hoetzel A, Park JW, Nakahira K, Wang X, Choi AMK. Mechanisms of cell death in oxidative stress. Antioxid Redox Signal 2007; 9:49-89. [PMID: 17115887 DOI: 10.1089/ars.2007.9.49] [Citation(s) in RCA: 876] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reactive oxygen or nitrogen species (ROS/RNS) generated endogenously or in response to environmental stress have long been implicated in tissue injury in the context of a variety of disease states. ROS/RNS can cause cell death by nonphysiological (necrotic) or regulated pathways (apoptotic). The mechanisms by which ROS/RNS cause or regulate apoptosis typically include receptor activation, caspase activation, Bcl-2 family proteins, and mitochondrial dysfunction. Various protein kinase activities, including mitogen-activated protein kinases, protein kinases-B/C, inhibitor-of-I-kappaB kinases, and their corresponding phosphatases modulate the apoptotic program depending on cellular context. Recently, lipid-derived mediators have emerged as potential intermediates in the apoptosis pathway triggered by oxidants. Cell death mechanisms have been studied across a broad spectrum of models of oxidative stress, including H2O2, nitric oxide and derivatives, endotoxin-induced inflammation, photodynamic therapy, ultraviolet-A and ionizing radiations, and cigarette smoke. Additionally ROS generated in the lung and other organs as the result of high oxygen therapy or ischemia/reperfusion can stimulate cell death pathways associated with tissue damage. Cells have evolved numerous survival pathways to counter proapoptotic stimuli, which include activation of stress-related protein responses. Among these, the heme oxygenase-1/carbon monoxide system has emerged as a major intracellular antiapoptotic mechanism.
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Affiliation(s)
- Stefan W Ryter
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
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Månsson R, Hansson MJ, Morota S, Uchino H, Ekdahl CT, Elmér E. Re-evaluation of mitochondrial permeability transition as a primary neuroprotective target of minocycline. Neurobiol Dis 2007; 25:198-205. [PMID: 17067803 DOI: 10.1016/j.nbd.2006.09.008] [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] [Received: 07/17/2006] [Revised: 08/21/2006] [Accepted: 09/07/2006] [Indexed: 01/13/2023] Open
Abstract
Minocycline has been shown to be neuroprotective in ischemic and neurodegenerative disease models and could potentially be relevant for clinical use. We revisited the hypothesis that minocycline acts through direct inhibition of calcium-induced mitochondrial permeability transition (mPT) resulting in reduced release of cytochrome c (cyt c). Minocycline, at high dosage, was found to prevent calcium-induced mitochondrial swelling under energized conditions similarly to the mPT inhibitor cyclosporin A (CsA) in rodent mitochondria derived from the CNS. In contrast to CsA, minocycline dose-dependently reduced mitochondrial calcium retention capacity (CRC) and respiratory control ratios and was ineffective in the de-energized mPT assay. Further, minocycline did not inhibit calcium- or tBid-induced cyt c release. We conclude that the neuroprotective mechanism of minocycline is likely not related to direct inhibition of mPT and propose that the mitochondrial effects of minocycline may contribute to toxicity rather than tissue protection at high dosing in animals and humans.
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Affiliation(s)
- Roland Månsson
- Laboratory for Experimental Brain Research, Department of Clinical Sciences, Lund University, Sweden.
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27
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Szigeti A, Bellyei S, Gasz B, Boronkai A, Hocsak E, Minik O, Bognar Z, Varbiro G, Sumegi B, Gallyas F. Induction of necrotic cell death and mitochondrial permeabilization by heme binding protein 2/SOUL. FEBS Lett 2006; 580:6447-54. [PMID: 17098234 DOI: 10.1016/j.febslet.2006.10.067] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Revised: 10/25/2006] [Accepted: 10/30/2006] [Indexed: 10/23/2022]
Abstract
We found that heme-binding protein 2/SOUL sensitised NIH3T3 cells to cell death induced by A23187 and etoposide, but it did not affect reactive oxygen species formation. In the presence of sub-threshold calcium, recombinant SOUL provoked mitochondrial permeability transition (mPT) in vitro that was inhibited by cyclosporine A (CsA). This effect was verified in vivo by monitoring the dissipation of mitochondrial membrane potential. Flow cytometry analysis showed that SOUL promoted necrotic death in A23187 and etoposide treated cells, which effect was prevented by CsA. These data suggest that besides its heme-binding properties SOUL promotes necrotic cell death by inducing mPT.
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Affiliation(s)
- Andras Szigeti
- Institute of Oncotherapy, University of Pécs, Pécs, Hungary
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28
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Shalbuyeva N, Brustovetsky T, Bolshakov A, Brustovetsky N. Calcium-dependent spontaneously reversible remodeling of brain mitochondria. J Biol Chem 2006; 281:37547-58. [PMID: 17056496 DOI: 10.1074/jbc.m607263200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An exposure of cultured hippocampal neurons expressing mitochondrially targeted enhanced yellow fluorescent protein to excitotoxic glutamate resulted in reversible mitochondrial remodeling that in many instances could be interpreted as swelling. Remodeling was not evident if glutamate receptors were blocked with MK801, if Ca(2+) was omitted or substituted for Sr(2+) in the bath solution, if neurons were treated with carbonylcyanide p-trifluoromethoxyphenylhydrazone to depolarize mitochondria, or if neurons were pretreated with cyclosporin A or N-methyl-4-isoleucine-cyclosporin (NIM811) to inhibit the mitochondrial permeability transition. In the experiments with isolated brain synaptic or nonsynaptic mitochondria, Ca(2+) triggered transient, spontaneously reversible cyclosporin A-sensitive swelling closely resembling remodeling of organelles in cultured neurons. The swelling was accompanied by the release of cytochrome c, Smac/DIABLO, Omi/HtrA2, and AIF but not endonuclease G. Depolarization with carbonylcyanide p-trifluoromethoxyphenylhydrazone or inhibition of the Ca(2+) uniporter with Ru360 prevented rapid onset of the swelling. Sr(2+) depolarized mitochondria but failed to induce swelling. Neither inhibitors of the large conductance Ca(2+)-activated K(+) channel (charybdotoxin, iberiotoxin, quinine, and Ba(2+)) nor inhibitors of the mitochondrial ATP-sensitive K(+) channel (5-hydroxydecanoate and glibenclamide) suppressed swelling. Quinine, dicyclohexylcarbodiimide, and Mg(2+), inhibitors of the mitochondrial K(+)/H(+) exchanger, as well as external alkalization inhibited a recovery phase of the reversible swelling. In contrast to brain mitochondria, liver and heart mitochondria challenged with Ca(2+) experienced sustained swelling without spontaneous recovery. The proposed model suggests an involvement of the Ca(2+)-dependent transient K(+) influx into the matrix causing mitochondrial swelling followed by activation of the K(+)/H(+) exchanger leading to spontaneous mitochondrial contraction both in situ and in vitro.
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Affiliation(s)
- Natalia Shalbuyeva
- Department of Pharmacology and Toxicology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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29
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Mishra OP, Randis T, Ashraf QM, Delivoria-Papadopoulos M. Hypoxia-induced Bax and Bcl-2 protein expression, caspase-9 activation, DNA fragmentation, and lipid peroxidation in mitochondria of the cerebral cortex of newborn piglets: the role of nitric oxide. Neuroscience 2006; 141:1339-49. [PMID: 16777344 DOI: 10.1016/j.neuroscience.2006.05.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Revised: 04/25/2006] [Accepted: 05/04/2006] [Indexed: 01/05/2023]
Abstract
The present study tests the hypothesis that cerebral hypoxia results in increased ratio of Bax/Bcl-2, activation of caspase-9, lipid peroxidation, and DNA fragmentation in mitochondria of the cerebral cortex of newborn piglets and that the inhibition of nitric oxide synthase by N-nitro-L-arginine during hypoxia will prevent the events leading to mitochondrial DNA fragmentation. To test this hypothesis, six piglets, 3-5 days old, were divided into three groups: normoxic (n=5), hypoxic (n=5), and hypoxic-nitric oxide synthase (n=4). Hypoxic animals were exposed to a FiO2 of 0.6 for 60 min. Nitric oxide synthase (40 mg/kg) was infused over 60 min prior to hypoxia. Tissue hypoxia was confirmed by measuring levels of ATP and phosphocreatine. Cerebral cortical tissue mitochondria were isolated and purified using a discontinuous ficoll gradient. Mitochondrial Bax and Bcl-2 proteins were determined by Western blot. Caspase-9 activity in mitochondria was determined spectro-fluorometrically using fluorogenic substrate for caspase-9. Fluorescent compounds, an index of mitochondrial membrane lipid peroxidation, were determined spectrofluorometrically. Mitochondrial DNA was isolated and separated by electrophoresis on 1% agarose gel and stained with ethidium bromide. ATP levels (micromol/g brain) were 4.52+/-0.34 in normoxic, 1.18+/-0.29 in hypoxic (P<0.05) and 1.00+/-0.26 in hypoxic-nitric oxide synthase animals (P<0.05 vs. normoxic). Phosphocreatine levels (micromol/g brain) were 3.61+/-0.33 in normoxic, 0.70+/-0.20 in hypoxic (P<0.05 vs. normoxic) and 0.57+/-0.14 in hypoxic-nitric oxide synthase animals (P<0.05 vs. normoxic, P=NS vs. hypoxic). Bax density in mitochondrial membranes was 160+/-28 in normoxic and 324+/-65 in hypoxic (P<0.001 vs. normoxic). Bcl-2 density mitochondria was 96+/-18 in normoxic and 98+/-20 in hypoxic (P=NS vs. normoxic). Mitochondrial caspase-9 activity (nmol/mg protein/h) was 1.32+/-0.23 in normoxic and 2.25+/-0.24 in hypoxic (P<0.01 vs. normoxic). Levels of fluorescent compounds (microg of quinine sulfate/g protein) were 12.48+/-4.13 in normoxic and 37.92+/-7.62 in hypoxic (P=0.003 vs. normoxic). Densities (ODxmm2) of low molecular weight DNA fragments were 143+/-38 in normoxic, 365+/-152 in hypoxic, (P<0.05 vs. normoxic) and 163+/-25 in hypoxic-nitric oxide synthase animals (P<0.05 vs. hypoxic, P=NS vs. normoxic). The data demonstrate that hypoxia results in increased mitochondrial proapoptotic protein Bax, increased mitochondrial caspase-9 activity, increased mitochondrial lipid peroxidation, and increased fragmentation of DNA in mitochondria of the cerebral cortex of newborn piglets. The administration of a nitric oxide synthase inhibitor, nitric oxide synthase, prior to hypoxia prevented fragmentation of mitochondrial DNA, indicating that the hypoxia-induced mitochondrial DNA fragmentation is NO-mediated. We propose that NO free radicals generated during hypoxia lead to NO-mediated altered expression of Bax leading to increased ratio of pro-apoptotic/anti-apoptotic protein resulting in modification of mitochondrial membrane, and subsequently Ca2+-influx and fragmentation of mitochondrial DNA.
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Affiliation(s)
- O P Mishra
- Department of Pediatrics, Room 701, 7th Floor Heritage Building, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
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30
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Dutkowski P, Graf R, Clavien PA. Rescue of the cold preserved rat liver by hypothermic oxygenated machine perfusion. Am J Transplant 2006; 6:903-12. [PMID: 16611326 DOI: 10.1111/j.1600-6143.2006.01264.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The aim of the study was to investigate whether hypothermic oxygenated liver perfusion after cold liver preservation resuscitated metabolic parameters and whether this treatment had a benefit for liver viability upon reperfusion. We preserved rat livers either by cold storage (UW) for 10 h, or by perfusion for 3 h (oxygenated modified UW) after 10 h cold storage. We assessed viability of livers after preservation and after ischemic rewarming+normothermic reperfusion ex vivo. Ten hour cold storage reduced mitochondrial cytochrome oxidase and metabolically depleted the livers. Oxygenated perfusion after cold storage resulted in uploaded cellular energy charge and oxidized mitochondrial cytochrome oxidase. Reperfusion after 10 h cold storage increased formation of superoxid anions, release of cytosolic LDH, lipid peroxidation, caspase activities and led to disruption of sinusoidal endothelial cells. In contrast, reperfusion after 10 h cold storage+3 h hypothermic oxygenated perfusion resulted in no changes of lipid peroxidation, bile flow, energy charge, total glutathione, LDH release and of caspase activation, as compared to fresh resected livers. This study demonstrates, that a metabolically depleted liver due to cold storage can be energy recharged by short-termed cold machine perfusion. The machine perfused graft exhibited improved viability and functional integrity.
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Affiliation(s)
- P Dutkowski
- Department of Visceral and Transplantation Surgery, University Hospital Zürich, Switzerland.
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31
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Fuks B, Talaga P, Huart C, Hénichart JP, Bertrand K, Grimée R, Lorent G. In vitro properties of 5-(benzylsulfonyl)-4-bromo-2-methyl-3(2H)-pyridazinone: a novel permeability transition pore inhibitor. Eur J Pharmacol 2005; 519:24-30. [PMID: 16099453 DOI: 10.1016/j.ejphar.2005.06.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 06/23/2005] [Accepted: 06/30/2005] [Indexed: 12/16/2022]
Abstract
Despite the increasing implication of the permeability transition pore (PTP) in the pathophysiology of neurodegenerative diseases, few selective PTP inhibitors have been reported so far. Here, we evaluate the pharmacological properties of a novel PTP inhibitor, BBMP (5-(benzylsulfonyl)-4-bromo-2-methyl-3(2H)-pyridazinone). This drug was discovered from the screening of a compound library against the PTP using a functional assay with isolated mitochondria. Similarly to cyclosporin A, the drug prevented Ca2+-induced permeability transition and mitochondrial depolarization. BBMP appeared more potent that minocycline in both swelling and membrane potential assays displaying pIC50 values of 5.5+/-0.1 and 5.6+/-0.0, respectively. Unlike minocycline, BBMP dose-dependently prevented DNA fragmentation induced by KCl 25/5 mM shift and serum deprivation in cerebellar granule neurons with a pIC50 of 5.7+/-0.6. The inhibition of PTP-mediated cytochrome c release observed in isolated mitochondria at 10 and 100 microM may explain its neuroprotective properties in vitro. These data suggest that the mitochondrial PTP is potentially involved in neuronal cell death and that PTP inhibitors, like BBMP, may possess a therapeutic potential in neurodegenerative disorders.
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Affiliation(s)
- Bruno Fuks
- UCB, Center for CNS Innovation, Chemin du Foriest, 1420 Braine-l'Alleud, Belgium.
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32
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Nukala VN, Singh IN, Davis LM, Sullivan PG. Cryopreservation of brain mitochondria: a novel methodology for functional studies. J Neurosci Methods 2005; 152:48-54. [PMID: 16246427 DOI: 10.1016/j.jneumeth.2005.08.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 08/15/2005] [Accepted: 08/17/2005] [Indexed: 11/20/2022]
Abstract
Often, comparative studies involving large number of animals or human post-mortem tissue samples are precluded, especially those requiring structurally and functionally intact cells and/or organelles. The ability to 'bank' such samples for storage and restore or 'reanimate' them at a later time without causing damage to the structure and/or function becomes imperative. However, to date, such attempts have produced conflicting results. We here demonstrate for the first time that isolated rat brain mitochondria can be successfully cryopreserved and restored for later use. We added a well characterized cryoprotectant 10% (v/v) dimethyl sulfoxide (DMSO) to purified rat cortical mitochondria and allowed them to cool at a uniform rate of approximately 1 degree C/min and stored them at -80 degrees C. Freshly isolated as well as reanimated brain mitochondria were analyzed for respiration. Structural integrity of cryopreserved mitochondria was also verified by electron microscopy. Mitochondrial membrane marker levels were assessed along with cytochrome c levels. Intact structure and function of the cryopreserved brain mitochondria observed allows us the opportunity to store mitochondria for longer periods of time as well as perform metabolic studies as needed. This will considerably expand the time-frame required for carrying out functional analysis in large comparative studies.
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Affiliation(s)
- Vidya N Nukala
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
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33
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Jemmerson R, Dubinsky JM, Brustovetsky N. Cytochrome C release from CNS mitochondria and potential for clinical intervention in apoptosis-mediated CNS diseases. Antioxid Redox Signal 2005; 7:1158-72. [PMID: 16115019 DOI: 10.1089/ars.2005.7.1158] [Citation(s) in RCA: 49] [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: 11/12/2022]
Abstract
Apoptosis is critical for normal development and tissue homeostasis. However, its abnormal occurrence has been implicated in a number of disorders, including neurodegenerative diseases and stroke. Translocation of cytochrome c (Cyt c) from mitochondria to the cytoplasm is a key step in the initiation and/or amplification of apoptosis. Here we discuss Cyt c release in apoptosis with its impact on the CNS and review our studies of Cyt c release from isolated rat brain mitochondria in response to several insults. Calcium-induced Cyt c release, as occurs in neurons during stroke and ischemia, involves rupture of the mitochondrial outer membrane (MOM) and can be blocked by inhibitors of the mitochondrial permeability transition (mPT). Thus, inhibitors of the mPT have shown efficacy in animal models of ischemia. In contrast, proapoptotic proteins, such as BID, BAX, and BAK, induce Cyt c release independently of the mPT without lysing the MOM. Several inhibitors of BAX-induced Cyt c release have shown promise in models of CNS apoptosis. Because of their distinct mechanisms for Cyt c release, both the mPT and proapoptotic proteins should be targeted for effective clinical intervention in CNS disorders involving apoptosis.
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Affiliation(s)
- Ronald Jemmerson
- Department of Microbiology and Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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34
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Brustovetsky T, Antonsson B, Jemmerson R, Dubinsky JM, Brustovetsky N. Activation of calcium-independent phospholipase A2 (iPLA2) in brain mitochondria and release of apoptogenic factors by BAX and truncated BID. J Neurochem 2005; 94:980-94. [PMID: 16092941 DOI: 10.1111/j.1471-4159.2005.03248.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cleaved or truncated BID (tBID) is known to oligomerize both BAK and BAX. Previously, BAK and BAX lacing the C-terminal fragment (BAXDeltaC) were shown to induce modest cytochrome c (Cyt c) release from rat brain mitochondria when activated by tBID. We now show that tBID plus monomeric full-length BAX induce extensive release of Cyt c, Smac/DIABLO, and Omi/HtrA2 (but not endonuclease G and the apoptosis inducing factor) comparable to the release induced by alamethicin. This occurs independently of the permeability transition without overt changes in mitochondrial morphology. The mechanism of the release may involve formation of reactive oxygen species (ROS) and activation of calcium-independent phospholipase A(2) (iPLA(2)). Indeed, increased ROS production and activated iPLA(2) were observed prior to massive Cyt c release. Furthermore, the extent of inhibition of Cyt c release correlated with the degree of suppression of iPLA(2) by the inhibitors propranolol, dibucaine, 4-bromophenacyl bromide, and bromenol lactone. Consistent with a requirement for iPLA(2) in Cyt c release from brain mitochondria, synthetic liposomes composed of lipids mimicking the outer mitochondrial membrane (OMM) but lacing iPLA(2) failed to release 10 kDa fluorescent dextran (FD-10) in response to tBID plus BAX. We propose that tBID plus BAX activate ROS generation, which subsequently augments iPLA(2) activity leading to changes in the OMM that allow translocation of certain mitochondrial proteins from the intermembrane space.
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Affiliation(s)
- Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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35
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Wang X, Zhang J, Kim HP, Wang Y, Choi AMK, Ryter SW. Bcl-XL disrupts death-inducing signal complex formation in plasma membrane induced by hypoxia/reoxygenation. FASEB J 2005; 18:1826-33. [PMID: 15576486 DOI: 10.1096/fj.04-2047com] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hypoxia/reoxygenation (H/R) causes cellular injury and death. The cell death pathways induced by H/R remain incompletely understood. H/R can induce Bid and Bax mitochondrial translocation and cytochrome c release. Using mouse lung endothelial cells (MLEC), we examined the role of Bcl-X(L), an anti-apoptotic Bcl-2-related protein, in H/R-induced cell death. The expression of Bcl-X(L) protected MLEC against H/R-induced cell death by blocking Bax and Bid translocation and inhibiting mitochondrial cytochrome c release. Bcl-X(L) expression inhibited caspase-8 cleavage and death-inducing signal complex (DISC) formation in plasma membrane. By isolating mitochondrial, nuclear, and Golgi fractions, we found that H/R induced DISC formation in these organelles. Bcl-X(L) expression inhibited DISC formation in the nuclear and Golgi fractions relative to LacZ-infected controls. In contrast, DISC formation was elevated in the mitochondrial fraction of Bcl-X(L)-infected cells. GRASP65, a Golgi-associated protein, physically associated with Fas and caspase-8; Bcl-X(L) expression decreased these associations. Bcl-X(L) expression also up-regulated FLIP, a caspase-8 inhibitor. In conclusion, Bcl-X(L) may inactivate caspase-8 by decreasing DISC formation in the plasma membrane, nucleus, and Golgi complex while diverting DISC formation to the mitochondria. The inhibitory effects of Bcl-X(L) on DISC formation may play significant roles in protecting endothelial cells from H/R-induced cell death.
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Affiliation(s)
- Xue Wang
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213, USA
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36
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Clayton R, Clark JB, Sharpe M. Cytochrome c release from rat brain mitochondria is proportional to the mitochondrial functional deficit: implications for apoptosis and neurodegenerative disease. J Neurochem 2005; 92:840-9. [PMID: 15686486 DOI: 10.1111/j.1471-4159.2004.02918.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Apoptosis may be initiated in neurons via mitochondrial release of the respiratory protein, cytochrome c. The mechanism of cytochrome c release has been studied extensively, but little is known about its dynamics. It has been claimed that release is all-or-none, however, this is not consistent with accumulating evidence of cytosolic mechanisms for 'buffering' cytochrome c. This study has attempted to model an underlying disease pathology, rather than inducing apoptosis directly. The model adopted was diminished activity of the mitochondrial respiratory chain complex I, a recognized feature of Parkinson's disease. Titration of rat brain mitochondrial respiratory function, with the specific complex I inhibitor rotenone, caused proportional release of cytochrome c from isolated synaptic and non-synaptic mitochondria. The mechanism of release was mediated, at least in part, by the mitochondrial outer membrane component Bak and voltage-dependent anion channel rather than non-specific membrane rupture. Furthermore, preliminary data were obtained demonstrating that in primary cortical neurons, titration with rotenone induced cytochrome c release that was subthreshold for the induction of apoptosis. Implications for the therapy of neurodegenerative diseases are discussed.
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Affiliation(s)
- Rebecca Clayton
- Miriam Marks Division of Neurochemistry, Institute of Neurology, University College London, London, UK
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37
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Stavrovskaya IG, Kristal BS. The powerhouse takes control of the cell: is the mitochondrial permeability transition a viable therapeutic target against neuronal dysfunction and death? Free Radic Biol Med 2005; 38:687-97. [PMID: 15721979 DOI: 10.1016/j.freeradbiomed.2004.11.032] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Accepted: 11/30/2004] [Indexed: 11/22/2022]
Abstract
Stroke and neurodegenerative disease exert an increasing large toll on human health at the levels both of the individual and of society. As an example of each, in the United States, stroke is the major single cause of overall morbidity and mortality, and the financial costs of Alzheimer's disease alone dwarfs the entire federal medical research budget. It has been long recognized that mitochondrial energy production is essential for the second to second functions of the central nervous system (CNS), and that severe mitochondrial impairment is incompatible with normal cerebral function. The last decade, however, has brought a growing understanding that mitochondria play an even greater role than previously suspected. Increased understanding of the role of mitochondria in antioxidant defense and calcium homeostasis further solidified the importance of mitochondria in CNS function--just as increased understanding of mitochondrial roles in calcium-mediated toxicity and production of reactive species further exemplified the Janus role of mitochondria--as mediators of CNS dysfunction. Perhaps most unexpected, however, was the evidence that mitochondria serve as the dominant integrators, checkpoints, and amplifiers of the cell death signals in the CNS. The mechanism of propagation of cell death cascades by mitochondria remains controversial. In this review, we focus on the evidence that supports the involvement of an event termed the mitochondrial permeability transition that (i) occurs (patho)physiologically; (ii) occurs in the CNS, and; (iii) is a potential target for pharmaceutical intervention against CNS dysfunction, injury, and cell loss resulting from stroke, trauma, and neurodegenerative disease.
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Affiliation(s)
- Irina G Stavrovskaya
- Dementia Research Service, Burke Medical Research Institute, 785 Mamaroneck Avenue, White Plains, NY 10605, USA
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38
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Abstract
Cytomegaloviruses (CMVs), a subset of betaherpesviruses, employ multiple strategies to suppress apoptosis in infected cells and thus to delay their death. Human cytomegalovirus (HCMV) encodes at least two proteins that directly interfere with the apoptotic signaling pathways, viral inhibitor of caspase-8-induced apoptosis vICA (pUL36), and mitochondria-localized inhibitor of apoptosis vMIA (pUL37 x 1). vICA associates with pro-caspase-8 and appears to block its recruitment to the death-inducing signaling complex (DISC), a step preceding caspase-8 activation. vMIA binds and sequesters Bax at mitochondria, and interferes with BH3-only-death-factor/Bax-complex-mediated permeabilization of mitochondria. vMIA does not seem to either interact with Bak, a close structural and functional homologue of Bax, or to suppress Bak-mediated permeabilization of mitochondria and Bak-mediated apoptosis. All sequenced betaherpesviruses, including CMVs, encode close homologues of vICA, and those vICA homologues that have been tested, were found to be functional cell death suppressors. Overt sequence homologues of vMIA were found only in the genomes of primate CMVs, but recent observations made with murine CMV (MCMV) indicate that non-primate CMVs may also encode a cell death suppressor functionally resembling vMIA. The exact physiological roles and relative contributions of vMIA and vICA in suppressing death of CMV-infected cells in vivo have not been elucidated. There is strong evidence that the cell death suppressing function of vMIA is indispensable, and that vICA is dispensable for replication of HCMV. In addition to suppressed caspase-8 activation and sequestered Bax, CMV-infected cells display several other phenomena, less well characterized, that may diminish, directly or indirectly the extent of cell death.
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Affiliation(s)
- V S Goldmacher
- ImmunoGen, Inc., 128 Sidney St., Cambridge, MA 02139, USA.
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39
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Polster BM, Basañez G, Etxebarria A, Hardwick JM, Nicholls DG. Calpain I induces cleavage and release of apoptosis-inducing factor from isolated mitochondria. J Biol Chem 2005; 280:6447-54. [PMID: 15590628 DOI: 10.1074/jbc.m413269200] [Citation(s) in RCA: 309] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The translocation of apoptosis-inducing factor (AIF) from mitochondria to the nucleus has been implicated in the mechanism of glutamate excitotoxicity in cortical neurons and has been observed in vivo following acute rodent brain injuries. However, the mechanism and time course of AIF redistribution to the nucleus is highly controversial. Because elevated intracellular calcium is one of the most ubiquitous features of neuronal cell death, this study tested the hypothesis that cleavage of AIF by the calcium-activated protease calpain mediates its release from mitochondria. Both precursor and mature forms of recombinant AIF were cleaved near the amino terminus by calpain I in vitro. Mitochondrial outer membrane permeabilization by truncated Bid induced cytochrome c release from isolated liver or brain mitochondria but only induced AIF release in the presence of active calpain. Enzymatic inhibition of calpain by calpeptin precluded AIF release, demonstrating that proteolytic activity was required for release. Calpeptin and the mitochondrial permeability transition pore antagonist cyclosporin A also inhibited calcium-induced AIF release from mouse liver mitochondria, implicating the involvement of an endogenous mitochondrial calpain in release of AIF during permeability transition. Cleavage of AIF directly decreased its association with pure lipid vesicles of mitochondrial inner membrane composition. Taken together, these results define a novel mechanism of AIF release involving calpain processing and identify a potential molecular checkpoint for cytoprotective interventions.
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Affiliation(s)
- Brian M Polster
- The Buck Institute for Age Research, Novato, California 94945, USA.
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Becattini B, Sareth S, Zhai D, Crowell KJ, Leone M, Reed JC, Pellecchia M. Targeting apoptosis via chemical design: inhibition of bid-induced cell death by small organic molecules. ACTA ACUST UNITED AC 2005; 11:1107-17. [PMID: 15324812 DOI: 10.1016/j.chembiol.2004.05.022] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Revised: 05/19/2004] [Accepted: 05/19/2004] [Indexed: 11/22/2022]
Abstract
Bid is a key member of the Bcl-2 family proteins involved in the control of the apoptotic cascade in cells, leading to cell death. Uncontrolled cell death is associated with several human pathologies, such as neurodegenerative diseases and ischemic injuries. Therefore, Bid represents a potential yet unexplored and challenging target for strategies aimed at the development of therapeutic agents. Here we show that a multidisciplinary NMR-based approach that we named SAR by ILOEs (structure activity relationships by interligand nuclear Overhauser effect) allowed us to rationally design a series of 4-phenylsulfanyl-phenylamine derivatives that are capable of occupying a deep hydrophobic crevice on the surface of Bid. These compounds represent the first antiapoptotic small molecules targeting a Bcl-2 protein as shown by their ability to inhibit tBid-induced SMAC release, caspase-3 activation, and cell death.
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Affiliation(s)
- Barbara Becattini
- The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, USA
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Zoratti M, Szabò I, De Marchi U. Mitochondrial permeability transitions: how many doors to the house? BIOCHIMICA ET BIOPHYSICA ACTA 2005; 1706:40-52. [PMID: 15620364 DOI: 10.1016/j.bbabio.2004.10.006] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 10/20/2004] [Accepted: 10/21/2004] [Indexed: 12/18/2022]
Abstract
The inner mitochondrial membrane is famously impermeable to solutes not provided with a specific carrier. When this impermeability is lost, either in a developmental context or under stress, the consequences for the cell can be far-reaching. Permeabilization of isolated mitochondria, studied since the early days of the field, is often discussed as if it were a biochemically well-defined phenomenon, occurring by a unique mechanism. On the contrary, evidence has been accumulating that it may be the common outcome of several distinct processes, involving different proteins or protein complexes, depending on circumstances. A clear definition of this putative variety is a prerequisite for an understanding of mitochondrial permeabilization within cells, of its roles in the life of organisms, and of the possibilities for pharmacological intervention.
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Affiliation(s)
- Mario Zoratti
- CNR Institute of Neuroscience, Biomembranes Section, Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy.
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Banerjee J, Ghosh S. Bax increases the pore size of rat brain mitochondrial voltage-dependent anion channel in the presence of tBid. Biochem Biophys Res Commun 2004; 323:310-4. [PMID: 15351738 DOI: 10.1016/j.bbrc.2004.08.094] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Indexed: 11/23/2022]
Abstract
Voltage-dependent anion channel (VDAC), Bax, and tBid play a central role in apoptosis regulation but their functioning is still very controversial. VDAC forms voltage gated pore in planar lipid bilayers, and acts as the pathway for the movement of substances in and out of the mitochondria by passive diffusion. Here we report that there is increase in the pore size of VDAC in the presence of Bax and tBid through bilayer electrophysiological experiments. We hereby hypothesize that this increase in pore size might cause swelling in the mitochondria, leading to the rupture of mitochondrial outer membrane and release of cytochrome c causing brain cell death.
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Affiliation(s)
- Jyotirmoy Banerjee
- Department of Biophysics, University of Delhi South Campus, New Delhi 110021, India
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Saito A, Hayashi T, Okuno S, Nishi T, Chan PH. Modulation of the Omi/HtrA2 signaling pathway after transient focal cerebral ischemia in mouse brains that overexpress SOD1. ACTA ACUST UNITED AC 2004; 127:89-95. [PMID: 15306124 DOI: 10.1016/j.molbrainres.2004.05.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2004] [Indexed: 11/26/2022]
Abstract
Omi/HtrA2 is a novel protein that contributes to the regulation of mitochondrial apoptosis after a variety of cell death stimuli in vitro and is thought to negatively control the inhibitor-of-apoptosis protein (IAP) family. However, the Omi/HtrA2 pathway remains unknown in apoptotic neuronal cell death in vivo. To examine the role of the Omi/HtrA2 pathway and its relationship to oxidative stress after reperfusion following cerebral ischemia, we used a transient focal cerebral ischemia (tFCI) model in copper/zinc-superoxide dismutase (SOD1) transgenic mice and wild-type mice. We evaluated the link between the Omi/HtrA2 pathway and the caspase cascade reaction after tFCI by administration of a pan-caspase inhibitor, Z-VAD-FMK. We observed the time-dependent expression of Omi/HtrA2 and its binding to X-chromosome-linked IAP (Omi/XIAP) by immunohistochemistry, Western blotting and coimmunoprecipitation. Translocation of Omi/HtrA2 into the cytosolic space was detected during the early period after tFCI and was not affected by Z-VAD-FMK administration, but it was prevented by SOD1 overexpression. Coimmunoprecipitation revealed that Omi/XIAP transiently increased and that it was prevented by SOD1 overexpression. These results suggest that the Omi/HtrA2 pathway may play an important role in the progress of apoptotic neuronal cell death and that overexpression of SOD1 may attenuate this apoptotic cell death by preventing the Omi/HtrA2 cell signaling pathway.
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Affiliation(s)
- Atsushi Saito
- Department of Neurosurgery and Program in Neurosciences, Stanford University School of Medicine, Stanford, CA 94305-5487, USA
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De Marchi U, Campello S, Szabò I, Tombola F, Martinou JC, Zoratti M. Bax does not directly participate in the Ca(2+)-induced permeability transition of isolated mitochondria. J Biol Chem 2004; 279:37415-22. [PMID: 15229226 DOI: 10.1074/jbc.m314093200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mitochondrial permeability transition pore and Bax have both been proposed to be involved in the release of pro-apoptotic factors from mitochondria in the "intrinsic" pathway of apoptosis. The permeability transition pore is widely thought to be a supramolecular complex including or interacting with Bax. Given the relevance of the permeability transition in vivo, we have verified whether Bax influences the formation and/or the properties of the Ca(2+)/P(i)-induced permeability transition by using mitochondriaisolated from isogenic human colon cancer bax(+/-) and bax(-/-) HCT116 cell lines. We used mitochondria isolated from both types of cells and from Bax(+) cells exposed to apoptotic stimuli, as well as Bax-less mitochondria into which exogenous Bax had been incorporated. All exhibited the same behavior and pharmacological profile in swelling and Ca(2+)-retention experiments. Mitochondria from a bax(-)/bak(-) cell line also underwent an analogous Ca(2+)/P(i)-inducible swelling. This similarity indicates that Bax hasno major role in regulating the Ca(2+)-induced mitochondrial permeability transition.
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Affiliation(s)
- Umberto De Marchi
- CNR Institute of Neuroscience, Biomembranes Section and Department of Biomedical Sciences, University of Padova, Padova, Italy
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Rostovtseva TK, Antonsson B, Suzuki M, Youle RJ, Colombini M, Bezrukov SM. Bid, but Not Bax, Regulates VDAC Channels. J Biol Chem 2004; 279:13575-83. [PMID: 14729675 DOI: 10.1074/jbc.m310593200] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During apoptosis, cytochrome c is released from mitochondria into the cytosol, where it participates in caspase activation. Various and often conflicting mechanisms have been proposed to account for the increased permeability of the mitochondrial outer membrane that is responsible for this process. The voltage-dependent anion channel (VDAC) is the major permeability pathway for metabolites in the mitochondrial outer membrane and therefore is a very attractive candidate for cytochrome c translocation. Here, we report that properties of VDAC channels reconstituted into planar phospholipid membranes are unaffected by addition of the pro-apoptotic protein Bax under a variety of conditions. Contrary to other reports (Shimizu, S., Narita, M., and Tsujimoto, Y. (1999) Nature 399, 483-487; Shimizu, S., Ide, T., Yanagida, T., and Tsujimoto, Y. (2000) J. Biol. Chem. 275, 12321-12325; Shimizu, S., Konishi, A., Kodama, T., and Tsujimoto, Y. (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 3100-3105), we found no electrophysiologically detectable interaction between VDAC channels isolated from mammalian mitochondria and either monomeric or oligomeric forms of Bax. We conclude that Bax does not induce cytochrome c release by acting on VDAC. In contrast to Bax, another pro-apoptotic protein (Bid) proteolytically cleaved with caspase-8 affected the voltage gating of VDAC by inducing channel closure. We speculate that by decreasing the probability of VDAC opening, Bid reduces metabolite exchange between mitochondria and the cytosol, leading to mitochondrial dysfunction.
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Affiliation(s)
- Tatiana K Rostovtseva
- Laboratory of Physical and Structural Biology, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Akhtar RS, Ness JM, Roth KA. Bcl-2 family regulation of neuronal development and neurodegeneration. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1644:189-203. [PMID: 14996503 DOI: 10.1016/j.bbamcr.2003.10.013] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2003] [Accepted: 10/27/2003] [Indexed: 01/03/2023]
Abstract
Neuronal cell death is a key feature of both normal nervous system development and neuropathological conditions. The Bcl-2 family, via its regulation of both caspase-dependent and caspase-independent cell death pathways, is uniquely positioned to critically control neuronal cell survival. Targeted gene disruptions of specific bcl-2 family members and the generation of transgenic mice overexpressing anti- or pro-apoptotic Bcl-2 family members have confirmed the importance of the Bcl-2 family in the nervous system. Data from studies of human brain tissue and experimental animal models of neuropathological conditions support the hypothesis that the Bcl-2 family regulates cell death in the mature nervous system and suggest that pharmacological manipulation of Bcl-2 family action could prove beneficial in the treatment of human neurological conditions such as stroke and neurodegenerative diseases.
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Affiliation(s)
- Rizwan S Akhtar
- Division of Pediatric Neurology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35294, 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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Seo YW, Shin JN, Ko KH, Cha JH, Park JY, Lee BR, Yun CW, Kim YM, Seol DW, Kim DW, Yin XM, Kim TH. The Molecular Mechanism of Noxa-induced Mitochondrial Dysfunction in p53-Mediated Cell Death. J Biol Chem 2003; 278:48292-9. [PMID: 14500711 DOI: 10.1074/jbc.m308785200] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Genotoxic stresses stabilize the p53 tumor suppressor protein which, in turn, transactivates target genes to cause apoptosis. Although Noxa, a "BH3-only" member of the Bcl-2 family, was shown to be a target of p53-mediated transactivation and to function as a mediator of p53-dependent apoptosis through mitochondrial dysfunction, the molecular mechanism by which Noxa causes mitochondrial dysfunction is largely unknown. Here we show that two domains (BH3 domain and mitochondrial targeting domain) in Noxa are essential for the release of cytochrome c from mitochondria. Noxa-induced cytochrome c release is inhibited by permeability transition pore inhibitors such as CsA or MgCl2, and Noxa induces an ultra-structural change of mitochondria yielding "swollen" mitochondria that are unlike changes induced by tBid. This indicates that Noxa may activate the permeability transition-related pore to release cytochrome c from mitochondria into cytosol. Moreover, Bak-oligomerization, which is an essential event for tBid-induced cytochrome c release in the extrinsic death signaling pathway, is not associated with Noxa-induced cytochrome c release. This finding suggests that the pathway of Noxa-induced mitochondrial dysfunction is distinct from the one of tBid-induced mitochondrial dysfunction. Thus, we propose that there are at least two different pathways of mitochondrial dysfunction; one mediated through Noxa in response to genotoxic stresses and the other through tBid in response to death ligands.
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Affiliation(s)
- Young-Woo Seo
- Department of Biochemistry, Chosun University School of Medicine, Dong-Gu, Gwangju 501-759, Korea
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