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Fayet M, Long M, Han B, Belkorchia A, Delbac F, Polonais V. New insights into Microsporidia polar tube function and invasion mechanism. J Eukaryot Microbiol 2024:e13043. [PMID: 38973152 DOI: 10.1111/jeu.13043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/19/2024] [Accepted: 06/10/2024] [Indexed: 07/09/2024]
Abstract
Microsporidia comprise a large phylum of single-cell and obligate intracellular parasites that can infect a wide range of invertebrate and vertebrate hosts including humans. These fungal-related parasites are characterized by a highly reduced genome, a strong energy dependence on their host, but also by their unique invasion organelle known as the polar tube which is coiled within the resistant spore. Upon appropriate environmental stimulation, the long hollow polar tube (ranging from 50 to 500 μm in length) is extruded at ultra-fast speeds (300 μm/s) from the spore acting as a harpoon-like organelle to transport and deliver the infectious material or sporoplasm into the host cell. To date, seven polar tube proteins (PTPs) with distinct localizations along the extruded polar tube have been described. For example, the specific location of PTP4 and PTP7 at the tip of the polar tube supports their role in interacting with cellular receptor(s). This chapter provides a brief overview on the current understanding of polar tube structure and dynamics of extrusion, primarily through recent advancements in cryo-tomography and 3D reconstruction. It also explores the various mechanisms used for host cell invasion. Finally, recent studies on the structure and maturation of sporoplasm and its moving through the tube are discussed.
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Affiliation(s)
- Maurine Fayet
- Laboratoire "Microorganismes: Génome et Environnement", CNRS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Mengxian Long
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
| | - Bing Han
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Abdel Belkorchia
- Laboratoire "Microorganismes: Génome et Environnement", CNRS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Frédéric Delbac
- Laboratoire "Microorganismes: Génome et Environnement", CNRS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Valerie Polonais
- Laboratoire "Microorganismes: Génome et Environnement", CNRS, Université Clermont Auvergne, Clermont-Ferrand, France
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2
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Bernardi P, Carraro M, Lippe G. The mitochondrial permeability transition: Recent progress and open questions. FEBS J 2022; 289:7051-7074. [PMID: 34710270 PMCID: PMC9787756 DOI: 10.1111/febs.16254] [Citation(s) in RCA: 71] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 10/27/2021] [Indexed: 01/13/2023]
Abstract
Major progress has been made in defining the basis of the mitochondrial permeability transition, a Ca2+ -dependent permeability increase of the inner membrane that has puzzled mitochondrial research for almost 70 years. Initially considered an artefact of limited biological interest by most, over the years the permeability transition has raised to the status of regulator of mitochondrial ion homeostasis and of druggable effector mechanism of cell death. The permeability transition is mediated by opening of channel(s) modulated by matrix cyclophilin D, the permeability transition pore(s) (PTP). The field has received new impulse (a) from the hypothesis that the PTP may originate from a Ca2+ -dependent conformational change of F-ATP synthase and (b) from the reevaluation of the long-standing hypothesis that it originates from the adenine nucleotide translocator (ANT). Here, we provide a synthetic account of the structure of ANT and F-ATP synthase to discuss potential and controversial mechanisms through which they may form high-conductance channels; and review some intriguing findings from the wealth of early studies of PTP modulation that still await an explanation. We hope that this review will stimulate new experiments addressing the many outstanding problems, and thus contribute to the eventual solution of the puzzle of the permeability transition.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences and CNR Neuroscience InstituteUniversity of PadovaItaly
| | - Michela Carraro
- Department of Biomedical Sciences and CNR Neuroscience InstituteUniversity of PadovaItaly
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3
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Quarato G, Llambi F, Guy CS, Min J, Actis M, Sun H, Narina S, Pruett-Miller SM, Peng J, Rankovic Z, Green DR. Ca 2+-mediated mitochondrial inner membrane permeabilization induces cell death independently of Bax and Bak. Cell Death Differ 2022; 29:1318-1334. [PMID: 35726022 DOI: 10.1038/s41418-022-01025-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 05/27/2022] [Accepted: 06/03/2022] [Indexed: 12/15/2022] Open
Abstract
The ability of mitochondria to buffer a rapid rise in cytosolic Ca2+ is a hallmark of proper cell homeostasis. Here, we employed m-3M3FBS, a putative phospholipase C (PLC) agonist, to explore the relationships between intracellular Ca2+ imbalance, mitochondrial physiology, and cell death. m-3M3FBS induced a potent dose-dependent Ca2+ release from the endoplasmic reticulum (ER), followed by a rise in intra-mitochondrial Ca2+. When the latter exceeded the organelle buffering capacity, an abrupt mitochondrial inner membrane permeabilization (MIMP) occurred, releasing matrix contents into the cytosol. MIMP was followed by cell death that was independent of Bcl-2 family members and inhibitable by the intracellular Ca2+ chelator BAPTA-AM. Cyclosporin A (CsA), capable of blocking the mitochondrial permeability transition (MPT), completely prevented cell death induced by m-3M3FBS. However, CsA acted upstream of mitochondria by preventing Ca2+ release from ER stores. Therefore, loss of Ca2+ intracellular balance and mitochondrial Ca2+ overload followed by MIMP induced a cell death process that is distinct from Bcl-2 family-regulated mitochondrial outer membrane permeabilization (MOMP). Further, the inhibition of cell death by CsA or its analogues can be independent of effects on the MPT.
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Affiliation(s)
- Giovanni Quarato
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
| | - Fabien Llambi
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.,Relay Therapeutics, Cambridge, MA, 02139, USA
| | - Cliff S Guy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Jaeki Min
- Department of Chemical Biology & Therapeutic, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.,Amgen Inc., Thousand Oaks, CA, 91320, USA
| | - Marisa Actis
- Department of Chemical Biology & Therapeutic, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Huan Sun
- Department of Structural Biology, Department of Developmental Neurobiology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Shilpa Narina
- Department of Cell and Molecular Biology and The Center for Advanced Genome Engineering, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Shondra M Pruett-Miller
- Department of Cell and Molecular Biology and The Center for Advanced Genome Engineering, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Junmin Peng
- Department of Structural Biology, Department of Developmental Neurobiology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Zoran Rankovic
- Department of Chemical Biology & Therapeutic, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
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4
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Boyenle ID, Oyedele AK, Ogunlana AT, Adeyemo AF, Oyelere FS, Akinola OB, Adelusi TI, Ehigie LO, Ehigie AF. Targeting the mitochondrial permeability transition pore for drug discovery: Challenges and opportunities. Mitochondrion 2022; 63:57-71. [PMID: 35077882 DOI: 10.1016/j.mito.2022.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/22/2021] [Accepted: 01/17/2022] [Indexed: 12/29/2022]
Abstract
Several drug targets have been amenable to drug discovery pursuit not until the characterization of the mitochondrial permeability transition pore (MPTP), a pore with an undefined molecular identity that forms on the inner mitochondrial membrane upon mitochondrial permeability transition (MPT) under the influence of calcium overload and oxidative stress. The opening of the pore which is presumed to cause cell death in certain human diseases also has implications under physiological parlance. Different models for this pore have been postulated following its first identification in the last six decades. The mitochondrial community has witnessed many protein candidates such as; voltage-dependent anion channel (VDAC), adenine nucleotide translocase (ANT), Mitochondrial phosphate carrier (PiC), Spastic Paralegin (SPG7), disordered proteins, and F1Fo ATPase. However, genetic studies have cast out most of these candidates with only F1Fo ATPase currently under intense argument. Cyclophilin D (CyPD) remains the widely accepted positive regulator of the MPTP known to date, but no drug candidate has emerged as its inhibitor, raising concern issues for therapeutics. Thus, in this review, we discuss various models of MPTP reported with the hope of stimulating further research in this field. We went beyond the classical description of the MPTP to ascribe a 'two-edged sword property' to the pore for therapeutic function in human disease because its inhibition and activation have pharmacological relevance. We suggested putative proteins upstream to CyPD that can regulate its activity and prevent cell deaths in neurodegenerative disease and ischemia-reperfusion injury.
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Affiliation(s)
- Ibrahim Damilare Boyenle
- Membrane Biochemistry and Biophysics Research Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria; Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Abdulquddus Kehinde Oyedele
- Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Abdeen Tunde Ogunlana
- Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Aishat Folashade Adeyemo
- Membrane Biochemistry and Biophysics Research Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | | | - Olateju Balikis Akinola
- Membrane Biochemistry and Biophysics Research Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Temitope Isaac Adelusi
- Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Leonard Ona Ehigie
- Computational Biology/Drug Discovery Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Adeola Folasade Ehigie
- Membrane Biochemistry and Biophysics Research Laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.
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5
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González LF, Bevilacqua LE, Naves R. Nanotechnology-Based Drug Delivery Strategies to Repair the Mitochondrial Function in Neuroinflammatory and Neurodegenerative Diseases. Pharmaceutics 2021; 13:2055. [PMID: 34959337 PMCID: PMC8707316 DOI: 10.3390/pharmaceutics13122055] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/24/2021] [Accepted: 11/26/2021] [Indexed: 12/14/2022] Open
Abstract
Mitochondria are vital organelles in eukaryotic cells that control diverse physiological processes related to energy production, calcium homeostasis, the generation of reactive oxygen species, and cell death. Several studies have demonstrated that structural and functional mitochondrial disturbances are involved in the development of different neuroinflammatory (NI) and neurodegenerative (ND) diseases (NI&NDDs) such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Remarkably, counteracting mitochondrial impairment by genetic or pharmacologic treatment ameliorates neurodegeneration and clinical disability in animal models of these diseases. Therefore, the development of nanosystems enabling the sustained and selective delivery of mitochondria-targeted drugs is a novel and effective strategy to tackle NI&NDDs. In this review, we outline the impact of mitochondrial dysfunction associated with unbalanced mitochondrial dynamics, altered mitophagy, oxidative stress, energy deficit, and proteinopathies in NI&NDDs. In addition, we review different strategies for selective mitochondria-specific ligand targeting and discuss novel nanomaterials, nanozymes, and drug-loaded nanosystems developed to repair mitochondrial function and their therapeutic benefits protecting against oxidative stress, restoring cell energy production, preventing cell death, inhibiting protein aggregates, and improving motor and cognitive disability in cellular and animal models of different NI&NDDs.
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Affiliation(s)
| | | | - Rodrigo Naves
- Immunology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Av. Independencia 1027, Santiago 8380453, Chile; (L.F.G.); (L.E.B.)
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6
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Carraro M, Carrer A, Urbani A, Bernardi P. Molecular nature and regulation of the mitochondrial permeability transition pore(s), drug target(s) in cardioprotection. J Mol Cell Cardiol 2020; 144:76-86. [DOI: 10.1016/j.yjmcc.2020.05.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/28/2020] [Accepted: 05/20/2020] [Indexed: 12/12/2022]
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7
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Han B, Takvorian PM, Weiss LM. Invasion of Host Cells by Microsporidia. Front Microbiol 2020; 11:172. [PMID: 32132983 PMCID: PMC7040029 DOI: 10.3389/fmicb.2020.00172] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/24/2020] [Indexed: 12/15/2022] Open
Abstract
Microsporidia are found worldwide and both vertebrates and invertebrates can serve as hosts for these organisms. While microsporidiosis in humans can occur in both immune competent and immune compromised hosts, it has most often been seen in the immune suppressed population, e.g., patients with advanced HIV infection, patients who have had organ transplantation, those undergoing chemotherapy, or patients using other immune suppressive agents. Infection can be associated with either focal infection in a specific organ (e.g., keratoconjunctivitis, cerebritis, or hepatitis) or with disseminated disease. The most common presentation of microsporidiosis being gastrointestinal infection with chronic diarrhea and wasting syndrome. In the setting of advanced HIV infection or other cases of profound immune deficiency microsporidiosis can be extremely debilitating and carries a significant mortality risk. Microsporidia are transmitted as spores which invade host cells by a specialized invasion apparatus the polar tube (PT). This review summarizes recent studies that have provided information on the composition of the spore wall and PT, as well as insights into the mechanism of invasion and interaction of the PT and spore wall with host cells during infection.
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Affiliation(s)
- Bing Han
- Department of Pathology, Albert Einstein College of Medicine, New York, NY, United States
- Department of Pathogenic Biology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Peter M. Takvorian
- Department of Pathology, Albert Einstein College of Medicine, New York, NY, United States
- Department of Biological Sciences, Rutgers University, Newark, NJ, United States
| | - Louis M. Weiss
- Department of Pathology, Albert Einstein College of Medicine, New York, NY, United States
- Department of Medicine, Albert Einstein College of Medicine, New York, NY, United States
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8
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Abstract
Adult cardiomyocytes are postmitotic cells that undergo very limited cell division. Thus, cardiomyocyte death as occurs during myocardial infarction has very detrimental consequences for the heart. Mitochondria have emerged as an important regulator of cardiovascular health and disease. Mitochondria are well established as bioenergetic hubs for generating ATP but have also been shown to regulate cell death pathways. Indeed many of the same signals used to regulate metabolism and ATP production, such as calcium and reactive oxygen species, are also key regulators of mitochondrial cell death pathways. It is widely hypothesized that an increase in calcium and reactive oxygen species activate a large conductance channel in the inner mitochondrial membrane known as the PTP (permeability transition pore) and that opening of this pore leads to necroptosis, a regulated form of necrotic cell death. Strategies to reduce PTP opening either by inhibition of PTP or inhibiting the rise in mitochondrial calcium or reactive oxygen species that activate PTP have been proposed. A major limitation of inhibiting the PTP is the lack of knowledge about the identity of the protein(s) that form the PTP and how they are activated by calcium and reactive oxygen species. This review will critically evaluate the candidates for the pore-forming unit of the PTP and discuss recent data suggesting that assumption that the PTP is formed by a single molecular identity may need to be reconsidered.
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Affiliation(s)
- Tyler M Bauer
- Laboratory of Cardiac Physiology, National Heart, Lung and Blood Institute, Bethesda, MD
| | - Elizabeth Murphy
- Laboratory of Cardiac Physiology, National Heart, Lung and Blood Institute, Bethesda, MD
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9
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Naryzhnaya NV, Maslov LN, Oeltgen PR. Pharmacology of mitochondrial permeability transition pore inhibitors. Drug Dev Res 2019; 80:1013-1030. [DOI: 10.1002/ddr.21593] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/08/2019] [Accepted: 08/12/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Natalia V. Naryzhnaya
- Laboratory of Experimental CardiologyCardiology Research Institute, Tomsk National Research Medical Center of the Russian Academy of Science Tomsk Russia
| | - Leonid N. Maslov
- Laboratory of Experimental CardiologyCardiology Research Institute, Tomsk National Research Medical Center of the Russian Academy of Science Tomsk Russia
| | - Peter R. Oeltgen
- Department of PathologyUniversity of Kentucky College of Medicine Lexington Kentucky
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10
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Han B, Ma Y, Tu V, Tomita T, Mayoral J, Williams T, Horta A, Huang H, Weiss LM. Microsporidia Interact with Host Cell Mitochondria via Voltage-Dependent Anion Channels Using Sporoplasm Surface Protein 1. mBio 2019; 10:e01944-19. [PMID: 31431557 PMCID: PMC6703431 DOI: 10.1128/mbio.01944-19] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 07/26/2019] [Indexed: 01/08/2023] Open
Abstract
Microsporidia are opportunistic intracellular pathogens that can infect a wide variety of hosts ranging from invertebrates to vertebrates. During invasion, the microsporidian polar tube pushes into the host cell, creating a protective microenvironment, the invasion synapse, into which the sporoplasm extrudes. Within the synapse, the sporoplasm then invades the host cell, forming a parasitophorous vacuole (PV). Using a proteomic approach, we identified Encephalitozoon hellem sporoplasm surface protein 1 (EhSSP1), which localized to the surface of extruded sporoplasms. EhSSP1 was also found to interact with polar tube protein 4 (PTP4). Recombinant EhSSP1 (rEhSSP1) bound to human foreskin fibroblasts, and both anti-EhSSP1 and rEhSSP1 caused decreased levels of host cell invasion, suggesting that interaction of SSP1 with the host cell was involved in invasion. Coimmunoprecipitation (Co-IP) followed by proteomic analysis identified host cell voltage-dependent anion channels (VDACs) as EhSSP1 interacting proteins. Yeast two-hybrid assays demonstrated that EhSSP1 was able to interact with VDAC1, VDAC2, and VDAC3. rEhSSP1 colocalized with the host mitochondria which were associated with microsporidian PVs in infected cells. Transmission electron microscopy revealed that the outer mitochondrial membrane interacted with meronts and the PV membrane, mitochondria clustered around meronts, and the VDACs were concentrated at the interface of mitochondria and parasite. Knockdown of VDAC1, VDAC2, and VDAC3 in host cells resulted in significant decreases in the number and size of the PVs and a decrease in mitochondrial PV association. The interaction of EhSSP1 with VDAC probably plays an important part in energy acquisition by microsporidia via its role in the association of mitochondria with the PV.IMPORTANCE Microsporidia are important opportunistic human pathogens in immune-suppressed individuals, such as those with HIV/AIDS and recipients of organ transplants. The sporoplasm is critical for establishing microsporidian infection. Despite the biological importance of this structure for transmission, there is limited information about its structure and composition that could be targeted for therapeutic intervention. Here, we identified a novel E. hellem sporoplasm surface protein, EhSSP1, and demonstrated that it can bind to host cell mitochondria via host VDAC. Our data strongly suggest that the interaction between SSP1 and VDAC is important for the association of mitochondria with the parasitophorous vacuole during microsporidian infection. In addition, binding of SSP1 to the host cell is associated with the final steps of invasion in the invasion synapse.
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Affiliation(s)
- Bing Han
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
| | - Yanfen Ma
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
| | - Vincent Tu
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
| | - Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
| | - Joshua Mayoral
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
| | - Tere Williams
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
| | - Aline Horta
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
| | - Huan Huang
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
| | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, New York, USA
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11
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Briston T, Selwood DL, Szabadkai G, Duchen MR. Mitochondrial Permeability Transition: A Molecular Lesion with Multiple Drug Targets. Trends Pharmacol Sci 2018; 40:50-70. [PMID: 30527591 DOI: 10.1016/j.tips.2018.11.004] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/05/2018] [Accepted: 11/06/2018] [Indexed: 12/13/2022]
Abstract
Mitochondrial permeability transition, as the consequence of opening of a mitochondrial permeability transition pore (mPTP), is a cellular catastrophe. Initiating bioenergetic collapse and cell death, it has been implicated in the pathophysiology of major human diseases, including neuromuscular diseases of childhood, ischaemia-reperfusion injury, and age-related neurodegenerative disease. Opening of the mPTP represents a major therapeutic target, as it can be mitigated by a number of compounds. However, clinical studies have so far been disappointing. We therefore address the prospects and challenges faced in translating in vitro findings to clinical benefit. We review the role of mPTP opening in disease, discuss recent findings defining the putative structure of the mPTP, and explore strategies to identify novel, clinically useful mPTP inhibitors, highlighting key considerations in the drug discovery process.
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Affiliation(s)
- Thomas Briston
- Neurology Innovation Centre, Hatfield Research Laboratories, Eisai Ltd., Hatfield, UK.
| | - David L Selwood
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London, UK
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London, UK; Department of Biomedical Sciences, University of Padua, Padua, Italy; The Francis Crick Institute, London, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London, UK
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12
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Baines CP, Gutiérrez-Aguilar M. The still uncertain identity of the channel-forming unit(s) of the mitochondrial permeability transition pore. Cell Calcium 2018; 73:121-130. [PMID: 29793100 PMCID: PMC5993635 DOI: 10.1016/j.ceca.2018.05.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/07/2018] [Accepted: 05/12/2018] [Indexed: 10/16/2022]
Abstract
Mitochondria from different organisms can undergo a sudden process of inner membrane unselective leakiness to molecules known as the mitochondrial permeability transition (MPT). This process has been studied for nearly four decades and several proteins have been claimed to constitute, or at least regulate the usually inactive pore responsible for this transition. However, no protein candidate proposed as the actual pore-forming unit has passed rigorous gain- or loss-of-function genetic tests. Here we review evidence for -and against- putative channel-forming components of the MPT pore. We conclude that the structure of the MPT pore still remains largely undefined and suggest that future studies should follow established technical considerations to unambiguously consolidate the channel forming constituent(s) of the MPT pore.
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Affiliation(s)
- Christopher P Baines
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, USA; Department of Biomedical Sciences, University of Missouri-Columbia, Columbia, MO 65211, USA; Department of Medical Pharmacology and Physiology, University of Missouri-Columbia, Columbia, MO 65211, USA.
| | - Manuel Gutiérrez-Aguilar
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
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13
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Magrì A, Reina S, De Pinto V. VDAC1 as Pharmacological Target in Cancer and Neurodegeneration: Focus on Its Role in Apoptosis. Front Chem 2018; 6:108. [PMID: 29682501 PMCID: PMC5897536 DOI: 10.3389/fchem.2018.00108] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 03/22/2018] [Indexed: 01/15/2023] Open
Abstract
Cancer and neurodegeneration are different classes of diseases that share the involvement of mitochondria in their pathogenesis. Whereas the high glycolytic rate (the so-called Warburg metabolism) and the suppression of apoptosis are key elements for the establishment and maintenance of cancer cells, mitochondrial dysfunction and increased cell death mark neurodegeneration. As a main actor in the regulation of cell metabolism and apoptosis, VDAC may represent the common point between these two broad families of pathologies. Located in the outer mitochondrial membrane, VDAC forms channels that control the flux of ions and metabolites across the mitochondrion thus mediating the organelle's cross-talk with the rest of the cell. Furthermore, the interaction with both pro-apoptotic and anti-apoptotic factors makes VDAC a gatekeeper for mitochondria-mediated cell death and survival signaling pathways. Unfortunately, the lack of an evident druggability of this protein, since it has no defined binding or active sites, makes the quest for VDAC interacting molecules a difficult tale. Pharmacologically active molecules of different classes have been proposed to hit cancer and neurodegeneration. In this work, we provide an exhaustive and detailed survey of all the molecules, peptides, and microRNAs that exploit VDAC in the treatment of the two examined classes of pathologies. The mechanism of action and the potential or effectiveness of each compound are discussed.
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Affiliation(s)
- Andrea Magrì
- Section of Molecular Biology, Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy.,Section of Biology and Genetics, Department of Biomedicine and Biotechnology, National Institute for Biomembranes and Biosystems, Section of Catania, Catania, Italy
| | - Simona Reina
- Section of Molecular Biology, Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy.,Section of Biology and Genetics, Department of Biomedicine and Biotechnology, National Institute for Biomembranes and Biosystems, Section of Catania, Catania, Italy
| | - Vito De Pinto
- Section of Biology and Genetics, Department of Biomedicine and Biotechnology, National Institute for Biomembranes and Biosystems, Section of Catania, Catania, Italy
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14
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Kon N, Satoh A, Miyoshi N. A small-molecule DS44170716 inhibits Ca 2+-induced mitochondrial permeability transition. Sci Rep 2017. [PMID: 28634393 PMCID: PMC5478606 DOI: 10.1038/s41598-017-03651-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Mitochondria are involved in a variety of physiological and pathological processes. Ca2+ uptake is one of the important functions of the organelle for maintenance of cellular Ca2+ homeostasis. In pathological conditions such as ischemia reperfusion injury, Ca2+ overload into mitochondria induces mitochondrial permeability transition (MPT), a critical step for cell death. Because inhibition of MPT is a promising approach to protecting cells and organs, it is important for drug discovery to identify novel chemicals or mechanisms to inhibit MPT. Here we report upon a small-molecule compound DS44170716 that inhibits Ca2+-induced MPT in rat liver isolated mitochondria. DS44170716 protects human liver HepG2 cells from Ca2+-induced death with a level of protection similar to cyclosporin A (CsA). The inhibitory mechanism of DS44170716 against MPT is independent on PPIF, a target of CsA. DS44170716 blocks Ca2+ flux into the mitochondria by decreasing mitochondrial membrane potential, while potently inhibiting mitochondrial complex III activities and weakly inhibiting complex IV and V activities. Similarly, complex III inhibitor antimycin A, complex IV inhibitor KCN or complex V inhibitor oligomycin inhibits Ca2+ uptake of isolated mitochondria. These results show that DS44170716 is a novel class inhibitor of MPT by blocking of mitochondrial complexes and Ca2+-overload into mitochondria.
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Affiliation(s)
- Naohiro Kon
- Medical Science Department, Daiichi Sankyo Co., Ltd., Tokyo, Japan.
| | - Atsushi Satoh
- Manufacturing Department III, Kitasato Daiichi Sankyo Vaccine Co., Ltd., Saitama, Japan
| | - Naoki Miyoshi
- End-Organ Disease Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan
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15
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Gutiérrez-Aguilar M. Commentary: Synthetic Ubiquinones Specifically Bind to Mitochondrial Voltage-Dependent Anion Channel 1 (VDAC1) in Saccharomyces cerevisiae Mitochondria. Front Mol Biosci 2017; 4:16. [PMID: 28393069 PMCID: PMC5364134 DOI: 10.3389/fmolb.2017.00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/10/2017] [Indexed: 11/13/2022] Open
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16
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Murai M, Okuda A, Yamamoto T, Shinohara Y, Miyoshi H. Synthetic Ubiquinones Specifically Bind to Mitochondrial Voltage-Dependent Anion Channel 1 (VDAC1) in Saccharomyces cerevisiae Mitochondria. Biochemistry 2017; 56:570-581. [DOI: 10.1021/acs.biochem.6b01011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Masatoshi Murai
- Division
of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Ayaka Okuda
- Division
of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takenori Yamamoto
- Institute
for Genome Research, University of Tokushima, Kuramotocho-3, Tokushima 770-8503, Japan
| | - Yasuo Shinohara
- Institute
for Genome Research, University of Tokushima, Kuramotocho-3, Tokushima 770-8503, Japan
| | - Hideto Miyoshi
- Division
of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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17
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Lee SY, Ahn SM, Wang Z, Choi YW, Shin HK, Choi BT. Neuroprotective effects of 2,3,5,4'-tetrahydoxystilbene-2-O-β-D-glucoside from Polygonum multiflorum against glutamate-induced oxidative toxicity in HT22 cells. JOURNAL OF ETHNOPHARMACOLOGY 2017; 195:64-70. [PMID: 27939422 DOI: 10.1016/j.jep.2016.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/25/2016] [Accepted: 12/02/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Since ancient times, Polygonum multiflorum Thunb. has been used to treat premature grey hair, dizziness, and blurred vision in East Asia. A major bioactive constituent of this medicinal herb, 2,3,5,4'-tetrahydoxystilbene-2-O-β-D-glucoside (THSG), has antioxidant activity and exerts beneficial effects on cognition and memory. AIM OF THE STUDY The purpose of the current study was to determine if THSG affects hippocampal neuronal cell death and mitochondrial function following exposure to oxidative stress. MATERIALS AND METHODS HT22 hippocampal cells with or without THSG pretreatment were exposed to glutamate, and the effects on cell viability and expression of molecules related to apoptotic cell death were examined using biochemical techniques, flow cytometry, western immunoblotting, and real-time polymerase chain reaction. RESULTS Pretreatment with THSG significantly attenuated glutamate-induced loss of cell viability and release of lactate dehydrogenase as well as apoptotic cell death. THSG inhibited generation of reactive oxygen species (ROS), expression of heme oxygenase-1, and activation of caspase-3 and calpain-1 proteases, all of which were increased by glutamate. THSG inhibited glutamate-induced disruption of mitochondrial membrane potential (MMP) and voltage-dependent anion channel-1. It also regulated the ratio of Bax to Bcl-2. CONCLUSIONS These results indicate that THSG has a marked neuroprotective effect against glutamate-induced hippocampal damage by decreasing ROS production and stabilizing MMP. These findings suggest the potential of THSG as a new therapeutic agent for the treatment of cognitive disorders.
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Affiliation(s)
- Sun Young Lee
- Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan 50612, Republic of Korea
| | - Sung Min Ahn
- Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan 50612, Republic of Korea
| | - Ziyu Wang
- Department of Horticultural Bioscience, College of Natural Resource and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - Young Whan Choi
- Department of Horticultural Bioscience, College of Natural Resource and Life Science, Pusan National University, Miryang 50463, Republic of Korea
| | - Hwa Kyoung Shin
- Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan 50612, Republic of Korea; Department of Korean Medical Science, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea; Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea
| | - Byung Tae Choi
- Korean Medical Science Research Center for Healthy-Aging, Pusan National University, Yangsan 50612, Republic of Korea; Department of Korean Medical Science, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea; Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan 50612, Republic of Korea.
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18
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Novoderezhkina EA, Zhivotovsky BD, Gogvadze VG. Induction of unspecific permeabilization of mitochondrial membrane and its role in cell death. Mol Biol 2016. [DOI: 10.1134/s0026893316010167] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Kumphune S, Surinkaew S, Chattipakorn SC, Chattipakorn N. Inhibition of p38 MAPK activation protects cardiac mitochondria from ischemia/reperfusion injury. PHARMACEUTICAL BIOLOGY 2015; 53:1831-1841. [PMID: 25880145 DOI: 10.3109/13880209.2015.1014569] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
CONTEXT Cardiac cell death and fatal arrhythmias during myocardial ischemia/reperfusion (I/R) can be reduced by p38 MAPK inhibition. However, the effects of p38 MAPK inhibition on cardiac mitochondria have not been investigated. OBJECTIVE We tested the hypothesis that p38 MAPK inhibition at different times during I/R protects cardiac mitochondrial functions. MATERIALS AND METHODS Adult Wistar rats were subjected to 30 min of left anterior descending coronary artery (LAD) occlusion, followed by 120 min of reperfusion. A 2 mg/kg bolus infusion of p38 MAPK inhibitor, SB203580, was given before or during ischemia, or at reperfusion. Mitochondrial function and ultrastructure were assessed and Western blots were performed. RESULTS Administration of SB203580 at any time point of I/R significantly attenuated the mitochondrial ultrastructure change, mitochondrial swelling, by increasing the absorbance at 540 nm (I/R control 0.42 ± 0.03; pretreatment 0.58 ± 0.04; during ischemia 0.49 ± 0.02; at reperfusion 0.51 ± 0.02, p < 0.05), similar to reactive oxygen species (ROS) generation (I/R control 1300 ± 48; pretreatment 1150 ± 30; during ischemia 1000 ± 50; at reperfusion 1050 ± 55, p < 0.05). Only SB203580 given before or during ischemia attenuated mitochondrial membrane depolarization (I/R control 0.78 ± 0.04; pretreatment 1.02 ± 0.03; during ischemia 1.05 ± 0.12, p < 0.05). In addition, pre-treatment of SB203580 significantly reduced the phosphorylation of p53, CREB, Bax, cytochrome c, and cleaved caspase 3. DISCUSSION AND CONCLUSION The results from this study showed for the first time that p38 MAPK inhibition protects mitochondria from I/R injury.
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Affiliation(s)
- Sarawut Kumphune
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University , Chiang Mai , Thailand
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20
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Hu D, Wu CQ, Li ZJ, Liu Y, Fan X, Wang QJ, Ding RG. Characterizing the mechanism of thiazolidinedione-induced hepatotoxicity: An in vitro model in mitochondria. Toxicol Appl Pharmacol 2015; 284:134-41. [PMID: 25727309 DOI: 10.1016/j.taap.2015.02.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/28/2015] [Accepted: 02/17/2015] [Indexed: 01/14/2023]
Abstract
OBJECTIVE To characterize the mechanism of action of thiazolidinedione (TZD)-induced liver mitochondrial toxicity caused by troglitazone, rosiglitazone, and pioglitazone in HepaRG cells. METHODS Human hepatoma cells (HepaRG) were treated with troglitazone, rosiglitazone, or pioglitazone (12.5, 25, and 50μM) for 48h. The Seahorse Biosciences XF24 Flux Analyzer was used to measure mitochondrial oxygen consumption. The effect of TZDs on reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected by flow cytometry. The mitochondrial ultrastructure of HepaRG cells was observed under a transmission electrical microscope (TEM). mtDNA content was evaluated by real-time PCR, and ATP content and mitochondrial respiratory chain (MRC) complex I, II, III, IV activity were measured via chemiluminescence. Results were considered statistically significant at p<0.05. RESULTS Among the three drugs, troglitazone exhibited the highest potency, followed by rosiglitazone, and then pioglitazone. The TZDs caused varying degrees of mitochondrial respiratory function disorders including decreases in oxygen consumption, MRC activity, and ATP level, and an elevation in ROS level. TZD treatment resulted in mtDNA content decline, reduction in MMP, and alterations of mitochondrial structure. CONCLUSION All investigated TZDs show a certain degree of mitochondrial toxicity, with troglitazone exhibiting the highest potency. The underlying mechanism of TZD-induced hepatotoxicity may be associated with alterations in mitochondrial respiratory function disorders, oxidative stress, and changes in membrane permeability. These parameters may be used early in drug development to further optimize risk:benefit profiles.
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Affiliation(s)
- Dan Hu
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Beijing 100850, PR China
| | - Chun-qi Wu
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Beijing 100850, PR China
| | - Ze-jun Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Beijing 100850, PR China; Guang Dong Pharmaceutical University, Guangzhou 510006, PR China
| | - Yue Liu
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Beijing 100850, PR China
| | - Xing Fan
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Beijing 100850, PR China
| | - Quan-jun Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Beijing 100850, PR China.
| | - Ri-gao Ding
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 27 Taiping Road, Beijing 100850, PR China.
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Abstract
Mitochondria are implicated in many important cellular functions covering the whole life cycle from mitochondrial biogenesis to cell death. Mitochondrial homeostasis is tightly regulated, and mitochondrial dysfunction is frequently associated with severe human pathologies (eg, cardiovascular diseases, cancer, and neurodegeneration). The permeability transition pore (PTP) is an unselective voltage-dependent mitochondrial channel. Despite the extensive use of electrophysiology, biochemistry, pharmacology, and genetic invalidation in mice, the molecular identity of PTP is still unknown. Nevertheless, PTP is central to mitochondrial vital functions and can play a lethal role in many pathophysiological conditions. This review recapitulates the current knowledge of the various modes of conductance of the PTP channel and discusses their implication in the physiological roles of PTP and their regulation. Based on its involvement in normal physiology and human pathology, a better understanding of this channel and its roles remains a major goal for basic scientists and clinicians.
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Affiliation(s)
- Catherine Brenner
- INSERM UMR-S 769, LabEx LERMIT, Université de Paris-Sud, 5, Rue JB Clément, 92296 Châtenay-Malabry, France.
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22
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Siemen D, Ziemer M. What is the nature of the mitochondrial permeability transition poreand What is it Not? IUBMB Life 2013; 65:255-62. [DOI: 10.1002/iub.1130] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 12/07/2012] [Indexed: 12/23/2022]
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23
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Inhibition of the Mitochondrial Permeability Transition for Cytoprotection: Direct versus Indirect Mechanisms. Biochem Res Int 2012; 2012:213403. [PMID: 22675634 PMCID: PMC3364550 DOI: 10.1155/2012/213403] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 02/07/2012] [Indexed: 11/17/2022] Open
Abstract
Mitochondria are fascinating organelles, which fulfill multiple cellular functions, as diverse as energy production, fatty acid β oxidation, reactive oxygen species (ROS) production and detoxification, and cell death regulation. The coordination of these functions relies on autonomous mitochondrial processes as well as on sustained cross-talk with other organelles and/or the cytosol. Therefore, this implies a tight regulation of mitochondrial functions to ensure cell homeostasis. In many diseases (e.g., cancer, cardiopathies, nonalcoholic fatty liver diseases, and neurodegenerative diseases), mitochondria can receive harmful signals, dysfunction and then, participate to pathogenesis. They can undergo either a decrease of their bioenergetic function or a process called mitochondrial permeability transition (MPT) that can coordinate cell death execution. Many studies present evidence that protection of mitochondria limits disease progression and severity. Here, we will review recent strategies to preserve mitochondrial functions via direct or indirect mechanisms of MPT inhibition. Thus, several mitochondrial proteins may be considered for cytoprotective-targeted therapies.
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24
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Godbole A, Mitra R, Dubey AK, Reddy PS, Mathew MK. Bacterial expression, purification and characterization of a rice voltage-dependent, anion-selective channel isoform, OsVDAC4. J Membr Biol 2011; 244:67-80. [PMID: 22057934 DOI: 10.1007/s00232-011-9399-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Accepted: 10/15/2011] [Indexed: 10/15/2022]
Abstract
The voltage-dependent anion-selective channel (VDAC) is the most abundant protein in the mitochondrial outer membrane and forms the major conduit for metabolite transport across this membrane. VDACs from different sources show varied primary sequence but conserved functional properties. Here, we report on the characterization of a rice channel, OsVDAC4, which complements a VDAC1 deficiency in yeast. We present a consensus secondary structure prediction of an N-terminal α-helix and 19 β-strands. Bacterially expressed OsVDAC4 was purified from inclusion bodies into detergent-containing solution, where it is largely helical. Detergent-solubilized OsVDAC4 inserts spontaneously into artificial membranes of two topologies-spherical liposomes and planar bilayers. Insertion into liposomes results in an increase in β-structure. Transport of polyethylene glycols was used to estimate a pore diameter of ~2.6 nm in liposomes. Channels formed in planar bilayers exhibit large conductance (4.6 ± 0.3 nS in 1 M KCl), strong voltage dependence and weak anion selectivity. The open state of the channel is shown to be permeable to ATP. These data are consistent with a large β-barrel pore formed by OsVDAC4 on inserting into membranes. This study forms a platform to carry out studies of the interaction of OsVDAC4 with putative modulators.
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Affiliation(s)
- Ashwini Godbole
- National Centre for Biological Sciences, TIFR, UAS-GKVK Campus, Bangalore, India
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25
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McCommis KS, Baines CP. The role of VDAC in cell death: friend or foe? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1444-50. [PMID: 22062421 DOI: 10.1016/j.bbamem.2011.10.025] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/18/2011] [Accepted: 10/24/2011] [Indexed: 11/16/2022]
Abstract
As the voltage-dependent anion channel (VDAC) forms the interface between mitochondria and the cytosol, its importance in metabolism is well understood. However, research on VDAC's role in cell death is a rapidly growing field, unfortunately with much confusing and contradictory results. The fact that VDAC plays a role in outer mitochondrial membrane permeabilization is undeniable, however, the mechanisms behind this remain very poorly understood. In this review, we will summarize the studies that show evidence of VDAC playing a role in cell death. To begin, we will discuss the evidence for and against VDAC's involvement in mitochondrial permeability transition (MPT) and attempt to clarify that VDAC is not an essential component of the MPT pore (MPTP). Next, we will evaluate the remaining literature on VDAC in cell death which can be divided into three models: proapoptotic agents escaping through VDAC, VDAC homo- or hetero-oligomerization, or VDAC closure resulting in outer mitochondrial membrane permeabilization through an unknown pathway. We will then discuss the growing list of modulators of VDAC activity that have been associated with induction/protection against cell death. This article is part of a Special Issue entitled: VDAC structure, function, and regulation of mitochondrial metabolism.
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Affiliation(s)
- Kyle S McCommis
- Department of Biomedical Sciences, University of Missouri, USA
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26
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von Stockum S, Basso E, Petronilli V, Sabatelli P, Forte MA, Bernardi P. Properties of Ca(2+) transport in mitochondria of Drosophila melanogaster. J Biol Chem 2011; 286:41163-41170. [PMID: 21984833 DOI: 10.1074/jbc.m111.268375] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have studied the pathways for Ca(2+) transport in mitochondria of the fruit fly Drosophila melanogaster. We demonstrate the presence of ruthenium red (RR)-sensitive Ca(2+) uptake, of RR-insensitive Ca(2+) release, and of Na(+)-stimulated Ca(2+) release in energized mitochondria, which match well characterized Ca(2+) transport pathways of mammalian mitochondria. Following larger matrix Ca(2+) loading Drosophila mitochondria underwent spontaneous RR-insensitive Ca(2+) release, an event that in mammals is due to opening of the permeability transition pore (PTP). Like the PTP of mammals, Drosophila Ca(2+)-induced Ca(2+) release could be triggered by uncoupler, diamide, and N-ethylmaleimide, indicating the existence of regulatory voltage- and redox-sensitive sites and was inhibited by tetracaine. Unlike PTP-mediated Ca(2+) release in mammals, however, it was (i) insensitive to cyclosporin A, ubiquinone 0, and ADP; (ii) inhibited by P(i), as is the PTP of yeast mitochondria; and (iii) not accompanied by matrix swelling and cytochrome c release even in KCl-based medium. We conclude that Drosophila mitochondria possess a selective Ca(2+) release channel with features intermediate between the PTP of yeast and mammals.
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Affiliation(s)
- Sophia von Stockum
- Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of I-35121 Padova, Italy
| | - Emy Basso
- Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of I-35121 Padova, Italy
| | - Valeria Petronilli
- Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of I-35121 Padova, Italy
| | - Patrizia Sabatelli
- Institute of Molecular Genetics at the Istituto Ortopedico Rizzoli, I-40126 Bologna, Italy
| | - Michael A Forte
- Vollum Institute, Oregon Health & Sciences University, Portland, Oregon 97239
| | - Paolo Bernardi
- Consiglio Nazionale delle Ricerche Institute of Neuroscience and Department of Biomedical Sciences, University of I-35121 Padova, Italy.
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27
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Serviddio G, Bellanti F, Vendemiale G, Altomare E. Mitochondrial dysfunction in nonalcoholic steatohepatitis. Expert Rev Gastroenterol Hepatol 2011; 5:233-44. [PMID: 21476918 DOI: 10.1586/egh.11.11] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The pathogenesis of nonalcoholic steatohepatitis (NASH) is poorly understood and the mechanisms are still being elucidated. Mitochondrial dysfunction participates at different levels in NASH pathogenesis since it impairs fatty liver homeostasis and induces overproduction of free radicals that in turn trigger lipid peroxidation and cell death. In this article, we review the role of mitochondria in fat metabolism, energy homeostasis and reactive oxygen species production, with a focus on the role of mitochondrial impairment and uncoupling proteins in the pathophysiology of NASH progression. The potential effects of some molecules targeted to mitochondria are also discussed.
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Affiliation(s)
- Gaetano Serviddio
- CURE (Centre for Liver Disease Research and Treatment), Department of Medical and Occupational Sciences, University of Foggia, 70124 Foggia, Italy.
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28
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A pore way to die: the role of mitochondria in reperfusion injury and cardioprotection. Biochem Soc Trans 2010; 38:841-60. [DOI: 10.1042/bst0380841] [Citation(s) in RCA: 238] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In addition to their normal physiological role in ATP production and metabolism, mitochondria exhibit a dark side mediated by the opening of a non-specific pore in the inner mitochondrial membrane. This mitochondrial permeability transition pore (MPTP) causes the mitochondria to breakdown rather than synthesize ATP and, if unrestrained, leads to necrotic cell death. The MPTP is opened in response to Ca2+ overload, especially when accompanied by oxidative stress, elevated phosphate concentration and adenine nucleotide depletion. These conditions are experienced by the heart and brain subjected to reperfusion after a period of ischaemia as may occur during treatment of a myocardial infarction or stroke and during heart surgery. In the present article, I review the properties, regulation and molecular composition of the MPTP. The evidence for the roles of CyP-D (cyclophilin D), the adenine nucleotide translocase and the phosphate carrier are summarized and other potential interactions with outer mitochondrial membrane proteins are discussed. I then review the evidence that MPTP opening mediates cardiac reperfusion injury and that MPTP inhibition is cardioprotective. Inhibition may involve direct pharmacological targeting of the MPTP, such as with cyclosporin A that binds to CyP-D, or indirect inhibition of MPTP opening such as with preconditioning protocols. These invoke complex signalling pathways to reduce oxidative stress and Ca2+ load. MPTP inhibition also protects against congestive heart failure in hypertensive animal models. Thus the MPTP is a very promising pharmacological target for clinical practice, especially once more specific drugs are developed.
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Azzolin L, Basso E, Argenton F, Bernardi P. Mitochondrial Ca2+ transport and permeability transition in zebrafish (Danio rerio). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1775-9. [PMID: 20633532 DOI: 10.1016/j.bbabio.2010.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 06/25/2010] [Accepted: 07/05/2010] [Indexed: 01/31/2023]
Abstract
We have studied mitochondrial Ca(2+) transport and the permeability transition (PT) in the teleost zebrafish (Danio rerio), a key model system for human diseases. Permeabilized zebrafish embryo cells displayed a mitochondrial energy-dependent Ca(2+) uptake system that, like the Ca(2+) uniporter of mammals, was inhibited by ruthenium red. Zebrafish mitochondria underwent a Ca(2+)-dependent PT that displayed Pi-dependent desensitization by cyclosporin A, and responded appropriately to key modulators of the mammalian PT pore (voltage, pH, ubiquinone 0, dithiol oxidants and cross linkers, ligands of the adenine nucleotide translocator, arachidonic acid). Opening of the pore was documented in intact cells, where it led to death that could largely be prevented by cyclosporin A. Our results represent a necessary step toward the use of zebrafish for the screening and validation of PTP inhibitors of potential use in human diseases, as recently shown for collagen VI muscular dystrophy [Telfer et al., 2010].
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Affiliation(s)
- Luca Azzolin
- Department of Biomedical Sciences and CNR Institute of Neuroscience, University of Padua, Italy
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30
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Abstract
The emergence of mitochondria as critical regulators of cardiac myocyte survival and death has revolutionized the field of cardiac biology. Indeed, it is now well recognized that mitochondrial dysfunction plays a crucial role in the pathogenesis of multiple cardiac diseases. A panoply of mitochondrial proteins/complexes ranging from canonical apoptosis proteins such as Bcl2 and Bax, through the mitochondrial permeability transition pore, to ion channels such as mitochondrial K(ATP) channels and connexin-43 have now been implicated as critical regulators of cardiac cell death. The purpose of this review, therefore, is to focus on these mitochondrial mediators/inhibitors of cell death and to address the specific mechanisms that underlie their ability to influence cardiac pathology.
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Affiliation(s)
- Christopher P Baines
- The Dalton Cardiovascular Research Center, Department of Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA.
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31
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Ryan CM, Souda P, Bassilian S, Ujwal R, Zhang J, Abramson J, Ping P, Durazo A, Bowie JU, Hasan SS, Baniulis D, Cramer WA, Faull KF, Whitelegge JP. Post-translational modifications of integral membrane proteins resolved by top-down Fourier transform mass spectrometry with collisionally activated dissociation. Mol Cell Proteomics 2010; 9:791-803. [PMID: 20093275 PMCID: PMC2871414 DOI: 10.1074/mcp.m900516-mcp200] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 01/15/2010] [Indexed: 11/06/2022] Open
Abstract
Integral membrane proteins remain a challenge to proteomics because they contain domains with physicochemical properties poorly suited to today's bottom-up protocols. These transmembrane regions may potentially contain post-translational modifications of functional significance, and thus development of protocols for improved coverage in these domains is important. One way to achieve this goal is by using top-down mass spectrometry whereby the intact protein is subjected to mass spectrometry and dissociation. Here we describe top-down high resolution Fourier transform mass spectrometry with collisionally activated dissociation to study post-translationally modified integral membrane proteins with polyhelix bundle and transmembrane porin motifs and molecular masses up to 35 kDa. On-line LC-MS analysis of the bacteriorhodopsin holoprotein yielded b- and y-ions that covered the full sequence of the protein and cleaved 79 of 247 peptide bonds (32%). The experiment proved that the mature sequence consists of residues 14-261, confirming N-terminal propeptide cleavage and conversion of N-terminal Gln-14 to pyrrolidone carboxylic acid (-17.02 Da) and C-terminal removal of Asp-262. Collisionally activated dissociation fragments localized the N(6)-(retinylidene) modification (266.20 Da) between residues 225-248 at Lys-229, the sole available amine in this stretch. Off-line nanospray of all eight subunits of the cytochrome b(6)f complex from the cyanobacterium Nostoc PCC 7120 defined various post-translational modifications, including covalently attached c-hemes (615.17 Da) on cytochromes f and b. Analysis of murine mitochondrial voltage-dependent anion channel established the amenability of the transmembrane beta-barrel to top-down MS and localized a modification site of the inhibitor Ro 68-3400 at Cys-232. Where neutral loss of the modification is a factor, only product ions that carry the modification should be used to assign its position. Although bond cleavage in some transmembrane alpha-helical domains was efficient, other regions were refractory such that their primary structure could only be inferred from the coincidence of genomic translation with precursor and product ions that spanned them.
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Affiliation(s)
- Christopher M. Ryan
- From ‡The Pasarow Mass Spectrometry Laboratory, The Neuropsychiatric Institute (NPI)-Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90024
| | - Puneet Souda
- From ‡The Pasarow Mass Spectrometry Laboratory, The Neuropsychiatric Institute (NPI)-Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90024
| | - Sara Bassilian
- From ‡The Pasarow Mass Spectrometry Laboratory, The Neuropsychiatric Institute (NPI)-Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90024
| | - Rachna Ujwal
- §Department of Physiology, David Geffen School of Medicine
| | - Jun Zhang
- §Department of Physiology, David Geffen School of Medicine
| | - Jeff Abramson
- §Department of Physiology, David Geffen School of Medicine
| | - Peipei Ping
- §Department of Physiology, David Geffen School of Medicine
- ¶Cardiovascular Research Laboratory
| | | | - James U. Bowie
- ‖Department of Chemistry and Biochemistry, and
- **The Molecular Biology Institute
| | | | | | | | - Kym F. Faull
- From ‡The Pasarow Mass Spectrometry Laboratory, The Neuropsychiatric Institute (NPI)-Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90024
- §§The Brain Research Institute, University of California Los Angeles, Los Angeles, California 90095, and
- **The Molecular Biology Institute
| | - Julian P. Whitelegge
- From ‡The Pasarow Mass Spectrometry Laboratory, The Neuropsychiatric Institute (NPI)-Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90024
- §§The Brain Research Institute, University of California Los Angeles, Los Angeles, California 90095, and
- **The Molecular Biology Institute
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Isoflurane postconditioning protects against reperfusion injury by preventing mitochondrial permeability transition by an endothelial nitric oxide synthase-dependent mechanism. Anesthesiology 2010; 112:73-85. [PMID: 19996950 DOI: 10.1097/aln.0b013e3181c4a607] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The role of endothelial nitric oxide synthase (eNOS) in isoflurane postconditioning (IsoPC)-elicited cardioprotection is poorly understood. The authors addressed this issue using eNOS mice. METHODS In vivo or Langendorff-perfused mouse hearts underwent 30 min of ischemia followed by 2 h of reperfusion in the presence and absence of postconditioning produced with isoflurane 5 min before and 3 min after reperfusion. Ca+-induced mitochondrial permeability transition (MPT) pore opening was assessed in isolated mitochondria. Echocardiography was used to evaluate ventricular function. RESULTS Postconditioning with 0.5, 1.0, and 1.5 minimum alveolar concentrations of isoflurane decreased infarct size from 56 +/- 10% (n = 10) in control to 48 +/- 10%, 41 +/- 8% (n = 8, P < 0.05), and 38 +/- 10% (n = 8, P < 0.05), respectively, and improved cardiac function in wild-type mice. Improvement in cardiac function by IsoPC was blocked by N-nitro-L-arginine methyl ester (a nonselective nitric oxide synthase inhibitor) administered either before ischemia or at the onset of reperfusion. Mitochondria isolated from postconditioned hearts required significantly higher in vitro Ca+ loading than did controls (78 +/- 29 microm vs. 40 +/- 25 microm CaCl2 per milligram of protein, n = 10, P < 0.05) to open the MPT pore. Hearts from eNOS mice displayed no marked differences in infarct size, cardiac function, and sensitivity of MPT pore to Ca+, compared with wild-type hearts. However, IsoPC failed to alter infarct size, cardiac function, or the amount of Ca+ necessary to open the MPT pore in mitochondria isolated from the eNOS hearts compared with control hearts. CONCLUSIONS IsoPC protects mouse hearts from reperfusion injury by preventing MPT pore opening in an eNOS-dependent manner. Nitric oxide functions as both a trigger and a mediator of cardioprotection produced by IsoPC.
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Halestrap AP, Pasdois P. The role of the mitochondrial permeability transition pore in heart disease. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1787:1402-15. [PMID: 19168026 DOI: 10.1016/j.bbabio.2008.12.017] [Citation(s) in RCA: 277] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 12/19/2008] [Accepted: 12/20/2008] [Indexed: 01/17/2023]
Abstract
Like Dr. Jeckyll and Mr. Hyde, mitochondria possess two distinct persona. Under normal physiological conditions they synthesise ATP to meet the energy needs of the beating heart. Here calcium acts as a signal to balance the rate of ATP production with ATP demand. However, when the heart is overloaded with calcium, especially when this is accompanied by oxidative stress, mitochondria embrace their darker side, and induce necrotic cell death of the myocytes. This happens acutely in reperfusion injury and chronically in congestive heart failure. Here calcium overload, adenine nucleotide depletion and oxidative stress combine forces to induce the opening of a non-specific pore in the mitochondrial membrane, known as the mitochondrial permeability transition pore (mPTP). The molecular nature of the mPTP remains controversial but current evidence implicates a matrix protein, cyclophilin-D (CyP-D) and two inner membrane proteins, the adenine nucleotide translocase (ANT) and the phosphate carrier (PiC). Inhibition of mPTP opening can be achieved with inhibitors of each component, but targeting CyP-D with cyclosporin A (CsA) and its non-immunosuppressive analogues is the best described. In animal models, inhibition of mPTP opening by either CsA or genetic ablation of CyP-D provides strong protection from both reperfusion injury and congestive heart failure. This confirms the mPTP as a promising drug target in human cardiovascular disease. Indeed, the first clinical trials have shown CsA treatment improves recovery after treatment of a coronary thrombosis with angioplasty.
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Affiliation(s)
- Andrew P Halestrap
- Department of Biochemistry and Bristol Heart Institute, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, UK.
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Halestrap AP. Mitochondria and reperfusion injury of the heart--a holey death but not beyond salvation. J Bioenerg Biomembr 2009; 41:113-21. [PMID: 19357938 DOI: 10.1007/s10863-009-9206-x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The combination of calcium overload and oxidative stress opens a non-specific pore in the inner mitochondrial membrane known as the mitochondrial permeability transition pore (MPTP). This uncouples oxidative phosphorylation and compromises intracellular ATP levels eventually leading to necrotic cell death. In cardiac ischemia and reperfusion, as during treatment of a coronary thrombosis or cardiac surgery, the extent of MPTP opening determines the amount of irreversible damage (infarct size). Furthermore, cardioprotection can be achieved by inhibiting MPTP opening either directly with cyclosporin A analogues, or indirectly by reducing oxidative stress. The detailed molecular mechanism of the MPTP remains uncertain. Knockout studies have confirmed important regulatory roles for cyclophilin-D (CyP-D) and the adenine nucleotide translocase (ANT) but not the voltage dependent anion channel. Our own studies have implicated a calcium-triggered conformational change of the mitochondrial phosphate carrier that is facilitated by CyP-D and modulated by the conformation of the ANT.
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Affiliation(s)
- Andrew P Halestrap
- The Department of Biochemistry and The Bristol Heart Institute, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
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35
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Brabant M, Baux L, Casimir R, Briand JP, Chaloin O, Porceddu M, Buron N, Chauvier D, Lassalle M, Lecoeur H, Langonné A, Dupont S, Déas O, Brenner C, Rebouillat D, Muller S, Borgne-Sanchez A, Jacotot E. A flavivirus protein M-derived peptide directly permeabilizes mitochondrial membranes, triggers cell death and reduces human tumor growth in nude mice. Apoptosis 2009; 14:1190-203. [DOI: 10.1007/s10495-009-0394-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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36
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Han W, Xie J, Li L, Liu Z, Hu X. Necrostatin-1 reverts shikonin-induced necroptosis to apoptosis. Apoptosis 2009; 14:674-86. [PMID: 19288276 DOI: 10.1007/s10495-009-0334-x] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Degterev et al. previously demonstrated that death receptor mediated apoptosis could be diverted to necroptosis when apoptosis signaling was blocked, suggesting that necroptosis may function as a backup mechanism to insure the elimination of damaged cells under certain conditions when apoptosis was inhibited. Here, we show that shikonin-induced necroptosis can be reverted to apoptosis in the presence of necrostatin-1 (Nec-1), a specific necroptosis inhibitor and that the death mode switch is at least partially due to the conversion from mitochondrial inner membrane permeability to mitochondrial outer membrane permeability, which is associated with Bax translocation. The data combined with the previous reports support a notion that apoptosis and necroptosis may function as reciprocal backup mechanisms of cellular demise. To the best of our knowledge, this is the first study to document a conversion from necroptosis to apoptosis.
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Affiliation(s)
- Weidong Han
- Cancer Institute, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China.
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37
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Javadov S, Karmazyn M, Escobales N. Mitochondrial permeability transition pore opening as a promising therapeutic target in cardiac diseases. J Pharmacol Exp Ther 2009; 330:670-8. [PMID: 19509316 DOI: 10.1124/jpet.109.153213] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In addition to their central role in ATP synthesis, mitochondria play a critical role in cell death. Oxidative stress accompanied by calcium overload, ATP depletion, and elevated phosphate levels induces mitochondrial permeability transition (MPT) with formation of nonspecific MPT pores (MPTP) in the inner mitochondrial membrane. Pore opening results in mitochondrial dysfunction with uncoupled oxidative phosphorylation and ATP hydrolysis, ultimately leading to cell death. For the past 20 years, three proteins have been accepted as key structural components of the MPTP: adenine nucleotide translocase (ANT) in the inner membrane, cyclophilin D (CyP-D) in the matrix, and the voltage-dependent anion channel (VDAC) in the outer membrane. However, most recent studies have questioned the molecular identity of the pores. Genetic studies have eliminated the VDAC as an essential component of MPTP and attributed a regulatory (rather than structural) role to ANT. Currently, the phosphate carrier appears to play a crucial role in MPTP formation. MPTP opening has been examined extensively in cardiac pathological conditions, including ischemia/reperfusion as well as heart failure. Accordingly, MPTP is accepted as a therapeutic target for both pharmacological and conditional strategies to block pore formation by direct interaction with MPTP components or indirectly by decreasing MPTP inducers. Inhibition of MPTP opening by reduction of CyP-D activity by nonimmunosuppressive analogs of cyclosporine A or sanglifehrin A, as well as attenuation of reactive oxygen species accumulation through mitochondria-targeted antioxidants, is the most promising. This review outlines our current knowledge of the structure and function of the MPTP and describes possible approaches for cardioprotection.
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Affiliation(s)
- Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, P. O. Box 365067, San Juan, PR.
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38
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Halestrap AP. What is the mitochondrial permeability transition pore? J Mol Cell Cardiol 2009; 46:821-31. [PMID: 19265700 DOI: 10.1016/j.yjmcc.2009.02.021] [Citation(s) in RCA: 688] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 02/19/2009] [Accepted: 02/20/2009] [Indexed: 12/12/2022]
Abstract
Under conditions of mitochondrial calcium overload, especially when accompanied by oxidative stress, elevated phosphate concentrations and adenine nucleotide depletion, a non-specific pore, the mitochondrial permeability transition pore (MPTP), opens in the inner mitochondrial membrane. MPTP opening enables free passage into the mitochondria of molecules of <1.5 kDa including protons. The resulting uncoupling of oxidative phosphorylation leads to ATP depletion and necrotic cell death and it is now widely recognised that MPTP opening is a major cause of reperfusion injury and an effective target for cardioprotection. The properties of the MPTP are well defined, but despite extensive research in many laboratories, its exact molecular identity remains uncertain. Knockout studies have confirmed a role for cyclophilin-D (CyP-D), probably mediated by its peptidyl-prolyl cis-trans isomerase activity facilitating a conformational change of an inner membrane protein. However, the identity of the membrane component(s) remains controversial. Knockout studies have eliminated an essential role for either the voltage dependent anion channel (VDAC) or the adenine nucleotide translocase (ANT), although a regulatory role for the ANT was confirmed. Our own studies implicate the mitochondrial phosphate carrier (PiC) in MPTP formation and are consistent with a calcium-triggered conformational change of the PiC, facilitated by CyP-D, inducing pore opening. We propose that this is enhanced by an association of the PiC with the "c" conformation of the ANT. Agents that modulate pore opening may act on either or both the PiC and the ANT. However, knockdown and reconstitution studies are awaited to confirm or refute this model.
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Affiliation(s)
- Andrew P Halestrap
- Department of Biochemistry and Bristol Heart Institute, University of Bristol, School of Medical Sciences, University Walk, Bristol, UK.
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39
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Di Lisa F, Bernardi P. A CaPful of mechanisms regulating the mitochondrial permeability transition. J Mol Cell Cardiol 2009; 46:775-80. [PMID: 19303419 DOI: 10.1016/j.yjmcc.2009.03.006] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 03/07/2009] [Accepted: 03/09/2009] [Indexed: 12/27/2022]
Abstract
Despite the lack of its molecular identification, the mitochondrial permeability transition pore (PTP) is a fascinating subject because of its important role in cell death. This holds especially true for cardiovascular diseases and in particular for ischemia-reperfusion injury, where research on PTP inhibition has been successfully translated from bench to clinical evidence of cardioprotection. In addition, recent reports extend the relevance of PTP to heart failure and atherosclerosis. This review summarizes the major factors involved in PTP control with specific emphasis on cardiovascular pathophysiology, and highlights recent findings on the pivotal role of inorganic phosphate as a mediator of the inhibitory effects of cyclosporin A and cyclophilin D ablation.
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Affiliation(s)
- Fabio Di Lisa
- Department of Biomedical Sciences and CNR Institute of Neuroscience, University of Padova, Padova, Italy.
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40
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The mitochondrial permeability transition pore and ischemia-reperfusion injury. Basic Res Cardiol 2009; 104:181-8. [PMID: 19242640 DOI: 10.1007/s00395-009-0004-8] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 01/22/2009] [Accepted: 01/26/2009] [Indexed: 12/27/2022]
Abstract
Mitochondrial dysfunction is an underlying cause of ischemia-reperfusion injury. In particular, ischemic injury induces dramatic increases in mitochondrial permeability, thereby instigating a chain of events that leads to both apoptotic and necrotic cardiomyocyte death. The mitochondrial permeability transition (MPT) pore, a large, non-specific channel that spans the inner mitochondrial membrane, is known to mediate the lethal permeability changes that initiate mitochondrial-driven cardiomyocyte death. The purpose of this review is to focus on the role of the MPT pore in ischemia-reperfusion injury, the mechanisms involved, and, in particular, what we do and do not know regarding the pore's molecular composition.
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41
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Baines CP. The molecular composition of the mitochondrial permeability transition pore. J Mol Cell Cardiol 2009; 46:850-7. [PMID: 19233198 DOI: 10.1016/j.yjmcc.2009.02.007] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 01/30/2009] [Accepted: 02/05/2009] [Indexed: 12/26/2022]
Abstract
Uncontrolled cell death is a fundamental cause of organ disease in humans. However, despite the need for us to delineate the molecular machinery that underlies cardiomyocyte death, our knowledge of these lethal cellular processes is still limited. The discovery that mitochondrial dysfunction, and in particular the mitochondrial permeability transition (MPT) pore, is often a common cause of the cardiac cell mortality that underlies numerous cardiac diseases has been a first crucial step. The purpose of this review is to outline our current understanding of the molecular identity of the MPT pore and the many questions that still need to be answered.
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Affiliation(s)
- Christopher P Baines
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, Missouri 65211, USA.
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42
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Lee JW, Shim YH. Mitochondrial Permeability Transition Pore and Cardioprotection Against Ischemia-reperfusion Injury. JOURNAL OF THE KOREAN MEDICAL ASSOCIATION 2009. [DOI: 10.5124/jkma.2009.52.10.1007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Jong Wha Lee
- Department of Anesthesiology and Pain Medicine/Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Korea.
| | - Yon Hee Shim
- Department of Anesthesiology and Pain Medicine/Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Korea.
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43
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Nawarak J, Huang-Liu R, Kao SH, Liao HH, Sinchaikul S, Chen ST, Cheng SL. Proteomics analysis of A375 human malignant melanoma cells in response to arbutin treatment. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1794:159-67. [PMID: 18996230 DOI: 10.1016/j.bbapap.2008.09.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 09/12/2008] [Accepted: 09/29/2008] [Indexed: 12/23/2022]
Abstract
Although the toxicogenomics of A375 human malignant melanoma cells treated with arbutin have been elucidated using DNA microarray, the proteomics of the cellular response to this compound are still poorly understood. In this study, we performed proteomic analyses to investigate the anticancer effect of arbutin on the protein expression profile in A375 cells. After treatment with arbutin (8 microg/ml) for 24, 48 and 72 h, the proteomic profiles of control and arbutin-treated A375 cells were compared, and 26 differentially expressed proteins (7 upregulated and 19 downregulated proteins) were identified by MALDI-Q-TOF MS and MS/MS. Among these proteins, 13 isoforms of six identical proteins were observed. Bioinformatic tools were used to search for protein function and to predict protein interactions. The interaction network of 14 differentially expressed proteins was found to be correlated with the downstream regulation of p53 tumor suppressor and cell apoptosis. In addition, three upregulated proteins (14-3-3G, VDAC-1 and p53) and five downregulated proteins (ENPL, ENOA, IMDH2, PRDX1 and VIME) in arbutin-treated A375 cells were validated by RT-PCR analysis. These proteins were found to play important roles in the suppression of cancer development.
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Affiliation(s)
- Jiraporn Nawarak
- Institute of Biological Chemistry and Genomics Research Center, Academia Sinica, Taipei 11529, Taiwan
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44
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Leung AWC, Varanyuwatana P, Halestrap AP. The mitochondrial phosphate carrier interacts with cyclophilin D and may play a key role in the permeability transition. J Biol Chem 2008; 283:26312-23. [PMID: 18667415 PMCID: PMC3258905 DOI: 10.1074/jbc.m805235200] [Citation(s) in RCA: 244] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Indexed: 12/21/2022] Open
Abstract
The mitochondrial permeability transition pore (MPTP) plays a key role in cell death, yet its molecular identity remains uncertain. Although knock-out studies have confirmed critical roles for both cyclophilin-D (CyP-D) and the adenine nucleotide translocase (ANT), given a strong enough stimulus MPTP opening can occur in the absence of either. Here we provide evidence that the mitochondrial phosphate carrier (PiC) may also be a critical component of the MPTP. Phenylarsine oxide (PAO) was found to activate MPTP opening in the presence of carboxyatractyloside (CAT) that prevents ANT binding to immobilized PAO. Only four proteins from solubilized CAT-treated beef heart inner mitochondrial membranes bound to immobilized PAO, one of which was the PiC. GST-CyP-D pull-down and co-immunoprecipitation studies revealed CsA-sensitive binding of PiC to CyP-D; this increased following diamide treatment. Co-immunoprecipitation of the ANT with the PiC was also observed but was insensitive to CsA treatment. N-ethylmaleimide and ubiquinone analogues (UQ(0) and Ro 68-3400) inhibited phosphate transport into rat liver mitochondria with the same concentration dependence as their inhibition of MPTP opening. UQ(0) and Ro 68-3400 also induced the "m" conformation of the ANT, as does NEM, and reduced the binding of both the PiC and ANT to the PAO column. We propose a model for the MPTP in which a calcium-triggered conformational change of the PiC, facilitated by CyP-D, induces pore opening. An interaction of the PiC with the ANT may enable agents that bind to either transporter to modulate pore opening.
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Affiliation(s)
| | | | - Andrew P. Halestrap
- Department of Biochemistry and The Bristol Heart Institute, University of
Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, United
Kingdom
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45
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Basso E, Petronilli V, Forte MA, Bernardi P. Phosphate is essential for inhibition of the mitochondrial permeability transition pore by cyclosporin A and by cyclophilin D ablation. J Biol Chem 2008; 283:26307-11. [PMID: 18684715 PMCID: PMC2546556 DOI: 10.1074/jbc.c800132200] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 08/01/2008] [Indexed: 12/22/2022] Open
Abstract
Energized mouse liver mitochondria displayed the same calcium retention capacity (a sensitive measure of the propensity of the permeability transition pore (PTP) to open) irrespective of whether phosphate, arsenate, or vanadate was the permeating anion. Unexpectedly, however, phosphate was specifically required for PTP desensitization by cyclosporin A (CsA) or by genetic inactivation of cyclophilin D (CyP-D). Indeed, when phosphate was replaced by arsenate, vanadate, or bicarbonate, the inhibitory effects of CsA and of CyP-D ablation on the PTP disappeared. After loading with the same amount of Ca(2+) in the presence of arsenate or vanadate but in the absence of phosphate, the sensitivity of the PTP to a variety of inducers was identical in mitochondria from wild-type mice, CyP-D-null mice, and wild-type mice treated with CsA. These findings call for a reassessment of conclusions on the role of the PTP in cell death that are based on the effects of CsA or of CyP-D ablation.
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Affiliation(s)
- Emy Basso
- Department of Biomedical Sciences and
Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of
Padova, Viale Giuseppe Colombo 3, I-35121 Padova, Italy and the
Vollum Institute, Oregon Health and Sciences
University, Portland, Oregon 97239
| | - Valeria Petronilli
- Department of Biomedical Sciences and
Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of
Padova, Viale Giuseppe Colombo 3, I-35121 Padova, Italy and the
Vollum Institute, Oregon Health and Sciences
University, Portland, Oregon 97239
| | - Michael A. Forte
- Department of Biomedical Sciences and
Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of
Padova, Viale Giuseppe Colombo 3, I-35121 Padova, Italy and the
Vollum Institute, Oregon Health and Sciences
University, Portland, Oregon 97239
| | - Paolo Bernardi
- Department of Biomedical Sciences and
Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of
Padova, Viale Giuseppe Colombo 3, I-35121 Padova, Italy and the
Vollum Institute, Oregon Health and Sciences
University, Portland, Oregon 97239
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Yang S, Liu T, Li S, Zhang X, Ding Q, Que H, Yan X, Wei K, Liu S. Comparative proteomic analysis of brains of naturally aging mice. Neuroscience 2008; 154:1107-20. [DOI: 10.1016/j.neuroscience.2008.04.012] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 04/08/2008] [Accepted: 04/09/2008] [Indexed: 11/28/2022]
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Lee YH, Chung MCM, Lin Q, Boelsterli UA. Troglitazone-induced hepatic mitochondrial proteome expression dynamics in heterozygous Sod2(+/-) mice: two-stage oxidative injury. Toxicol Appl Pharmacol 2008; 231:43-51. [PMID: 18495193 DOI: 10.1016/j.taap.2008.03.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2008] [Revised: 03/24/2008] [Accepted: 03/27/2008] [Indexed: 12/20/2022]
Abstract
The determinants of susceptibility to troglitazone-induced idiosyncratic liver injury have not yet been determined; however, troglitazone has been shown to target mitochondria and induce mitochondria-mediated hepatocellular injury in vitro. The aim of this study was to use a systems approach to analyze the dynamics of mitochondrial changes at the proteome level and more clearly define the mechanisms and time course of troglitazone hepatotoxicity by using a previously characterized mouse model that is highly sensitized to troglitazone hepatotoxicity. Mice heterozygous in mitochondrial superoxide dismutase-2 (Sod2(+/-)) were injected intraperitoneally with troglitazone (30 mg/kg/day) or vehicle daily for 2 or 4 weeks. Hepatic mitochondria were isolated, purified, and subjected to two-dimensional difference gel electrophoresis (2D-DIGE). We found that among the ~1500 resolved hepatic mitochondrial proteins, 70 exhibited significantly altered abundance after troglitazone treatment. MALDI-TOF/TOF MS/MS analysis revealed that early changes (2 weeks) included increased levels of heat shock protein family members (mortalin, HSP7C), Lon protease, and catalase, indicating induction of a mitochondrial stress response. In contrast, after 4 weeks, a number of critical proteins including ATP synthase beta-subunit, aconitase-2, and catalase exhibited decreased abundance, and total protein carbonyls were significantly increased, suggesting uncompensated oxidative damage. Aconitase-2 (ACO2) was decreased at both time points, making this protein a potential sensitive and early biomarker for mitochondrial oxidant stress. These results show that, in this murine model of underlying clinically silent mitochondrial stress, superimposed troglitazone induces a two-stage response: an initial adaptive response, followed by a toxic response involving oxidant injury to mitochondrial proteins.
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Affiliation(s)
- Yie Hou Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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Leung AWC, Halestrap AP. Recent progress in elucidating the molecular mechanism of the mitochondrial permeability transition pore. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:946-52. [PMID: 18407825 DOI: 10.1016/j.bbabio.2008.03.009] [Citation(s) in RCA: 250] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 03/04/2008] [Accepted: 03/19/2008] [Indexed: 12/16/2022]
Abstract
The mitochondrial permeability transition pore (MPTP) plays a key role in cell death, especially necrosis, and mediates the injury tissues such as the heart and brain experience following ischaemia and reperfusion. However, the molecular identity of the MPTP remains uncertain. Knockout studies have confirmed a role for cyclophilin-D (CyP-D) in pore opening, probably mediated by its peptidyl-prolyl cis-trans isomerase activity that facilitates a conformational change in an inner membrane protein. However, similar knockout studies have cast doubt on the central role of the adenine nucleotide translocase (ANT), previously regarded as a leading contender for the membrane component that forms the transmembrane channel of the MPTP. Here we review the evidence for and against a role for the ANT in MPTP opening and conclude that it usually plays a regulatory role rather than provide the transmembrane pore component. We suggest that the protein fulfilling the latter role is the mitochondrial phosphate carrier (PiC) and summarise recent evidence in support of this proposal. Our data are consistent with a model for the MPTP in which a calcium-triggered conformational change of the PiC, facilitated by CyP-D, induces pore opening. We propose that this is enhanced by an association of the PiC with the "c" conformation of the ANT. Agents that modulate pore opening may act on either or both the PiC and the ANT.
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Affiliation(s)
- Anna W C Leung
- Department of Biochemistry and Bristol Heart Institute, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, UK
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Halestrap AP, Clarke SJ, Khaliulin I. The role of mitochondria in protection of the heart by preconditioning. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1007-31. [PMID: 17631856 PMCID: PMC2212780 DOI: 10.1016/j.bbabio.2007.05.008] [Citation(s) in RCA: 299] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 05/18/2007] [Accepted: 05/23/2007] [Indexed: 12/16/2022]
Abstract
A prolonged period of ischaemia followed by reperfusion irreversibly damages the heart. Such reperfusion injury (RI) involves opening of the mitochondrial permeability transition pore (MPTP) under the conditions of calcium overload and oxidative stress that accompany reperfusion. Protection from MPTP opening and hence RI can be mediated by ischaemic preconditioning (IP) where the prolonged ischaemic period is preceded by one or more brief (2–5 min) cycles of ischaemia and reperfusion. Following a brief overview of the molecular characterisation and regulation of the MPTP, the proposed mechanisms by which IP reduces pore opening are reviewed including the potential roles for reactive oxygen species (ROS), protein kinase cascades, and mitochondrial potassium channels. It is proposed that IP-mediated inhibition of MPTP opening at reperfusion does not involve direct phosphorylation of mitochondrial proteins, but rather reflects diminished oxidative stress during prolonged ischaemia and reperfusion. This causes less oxidation of critical thiol groups on the MPTP that are known to sensitise pore opening to calcium. The mechanisms by which ROS levels are decreased in the IP hearts during prolonged ischaemia and reperfusion are not known, but appear to require activation of protein kinase Cε, either by receptor-mediated events or through transient increases in ROS during the IP protocol. Other signalling pathways may show cross-talk with this primary mechanism, but we suggest that a role for mitochondrial potassium channels is unlikely. The evidence for their activity in isolated mitochondria and cardiac myocytes is reviewed and the lack of specificity of the pharmacological agents used to implicate them in IP is noted. Some K+ channel openers uncouple mitochondria and others inhibit respiratory chain complexes, and their ability to produce ROS and precondition hearts is mimicked by bona fide uncouplers and respiratory chain inhibitors. IP may also provide continuing protection during reperfusion by preventing a cascade of MPTP-induced ROS production followed by further MPTP opening. This phase of protection may involve survival kinase pathways such as Akt and glycogen synthase kinase 3 (GSK3) either increasing ROS removal or reducing mitochondrial ROS production.
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Affiliation(s)
- Andrew P Halestrap
- Department of Biochemistry and Bristol Heart Institute, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, UK.
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Abstract
Previously, all biological measurements of intracellular electric fields (E fields), using voltage dyes or patch/voltage clamps, were confined to cellular membranes, which account for <0.1% of the total cellular volume. These membrane-dependent techniques also frequently require lengthy calibration steps for each cell or cell type measured. A new 30-nm "photonic voltmeter", 1000-fold smaller than existing voltmeters, enables, to our knowledge, the first complete three-dimensional E field profiling throughout the entire volume of living cells. These nanodevices are calibrated externally and then applied for E field determinations inside any live cell or cellular compartment, with no further calibration steps. The results indicate that the E fields from the mitochondrial membranes penetrate much deeper into the cytosol than previously estimated, indicating that, electrically, the cytoplasm cannot be described as a simple homogeneous solution, as often approximated, but should rather be thought of as a complex, heterogeneous hydrogel, with distinct microdomains.
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Affiliation(s)
- Katherine M Tyner
- Toxicology Program and Chemistry Department, University of Michigan, Ann Arbor, Michigan 48105, USA
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