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Shang Y, Li Z, Cai P, Li W, Xu Y, Zhao Y, Xia S, Shao Q, Wang H. Megamitochondria plasticity: function transition from adaption to disease. Mitochondrion 2023:S1567-7249(23)00053-3. [PMID: 37276954 DOI: 10.1016/j.mito.2023.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/08/2023] [Accepted: 06/02/2023] [Indexed: 06/07/2023]
Abstract
As the cell's energy factory and metabolic hub, mitochondria are critical for ATP synthesis to maintain cellular function. Mitochondria are highly dynamic organelles that continuously undergo fusion and fission to alter their size, shape, and position, with mitochondrial fusion and fission being interdependent to maintain the balance of mitochondrial morphological changes. However, in response to metabolic and functional damage, mitochondria can grow in size, resulting in a form of abnormal mitochondrial morphology known as megamitochondria. Megamitochondria are characterized by their considerably larger size, pale matrix, and marginal cristae structure and have been observed in various human diseases. In energy-intensive cells like hepatocytes or cardiomyocytes, the pathological process can lead to the growth of megamitochondria, which can further cause metabolic disorders, cell damage and aggravates the progression of the disease. Nonetheless, megamitochondria can also form in response to short-term environmental stimulation as a compensatory mechanism to support cell survival. However, extended stimulation can reverse the benefits of megamitochondria leading to adverse effects. In this review, we will focus on the findings of the different roles of megamitochondria, and their link to disease development to identify promising clinical therapeutic targets.
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Affiliation(s)
- Yuxing Shang
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China
| | - Zhanghui Li
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China
| | - Peiyang Cai
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China
| | - Wuhao Li
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China
| | - Ye Xu
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China
| | - Yangjing Zhao
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China
| | - Sheng Xia
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China
| | - Qixiang Shao
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China; Institute of Medical Genetics and Reproductive Immunity, School of Medical Science and Laboratory Medicine, Jiangsu College of Nursing, Huai'an 223002, Jiangsu, PR China.
| | - Hui Wang
- Reproductive Sciences Institute, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, PR China.
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2
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Ishibashi Y, Sugimoto T, Ichikawa Y, Akatsuka A, Miyata T, Nangaku M, Tagawa H, Kurokawa K. Glucose Dialysate Induces Mitochondrial DNA Damage in Peritoneal Mesothelial Cells. Perit Dial Int 2020. [DOI: 10.1177/089686080202200103] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Background It is known that peritoneal mesothelial cells (PMCs) are denuded in patients undergoing long-term continuous ambulatory peritoneal dialysis (CAPD); the mechanism of damage is not well known. A high quantity of glucose loaded onto PMCs in these patients may generate toxic radicals during the mitochondrial metabolism, leading to mitochondrial DNA damage that accumulates due to the incomplete repair system of this DNA. Objective To study damage to the PMCs of long-term CAPD patients, and to examine whether glucose overload accelerates this damage in vitro. Design Descriptive clinical and in vitro study. Participants Stable CAPD patients and nonuremic patients undergoing elective abdominal surgery. Methods ( 1 ) Clinical Samples: 13 peritoneal tissue samples from CAPD patients and 5 omental tissue samples from patients with normal renal function were investigated. PMCs in dialysate effluent were collected from another 13 stable CAPD patients. ( 2 ) In Vitro Samples: Primary cultured PMCs were incubated for up to 144 hours in medium containing one of the following: 5.6 mmol/L glucose (control), 56 mmol/L glucose (G), 222 mmol/L glucose (high G), or 222 mmol/L mannitol (high M; osmolar control for high G). The tissues and cells of clinical and in vitro samples were stained for light and immunoelectron microscopy with anti–8-hydroxy-2'-deoxyguanosine (anti–8-OH-dG) antibody, a marker of oxidative DNA damage. In vitro cells were also studied using transmission electron microscopy. Cellular ATP content, mitochondrial membrane potential, and intracellular generation of reactive oxygen species (ROS) were analyzed by luciferase–luciferin system, or by flow cytometry using rhodamine 123 and 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Results Biopsy specimens showed strong cytoplasmic staining with 8-OH-dG in patients on long-term CAPD, but only faint staining in patients with end-stage renal disease before the initiation of CAPD, and no staining in patients with normal renal function. Dialysate effluent showed strong granular staining with 8-OH-dG in most PMCs in all long-term CAPD patients, but only faint and focal staining in patients at the start and after 3 – 5 months of CAPD. In vitro experiments also showed strong granular staining by 8-OH-dG in most PMCs cultured in high G, weak staining in G and high M, and no staining in the control. Immunoelectron microscopy revealed the localization of 8-OH-dG to mitochondria. Transmission electron microscopy showed swelling of mitochondria, with decreased cristae, in PMCs cultured in high G. However, only partial expansion of mitochondria was seen in G and high M, and no changes were seen in the control. Cellular ATP content and mitochondrial membrane potential were reduced early, followed by an increase when cultured in high G. Intracellular ROS production was also increased in PMCs cultured in high G and high M. Conclusions These data suggest that high-glucose peritoneal dialysate may promote oxidative mitochondrial DNA damage in PMCs in CAPD patients.
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Affiliation(s)
- Yoshitaka Ishibashi
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo
- Molecular and Cellular Nephrology, Institute of Medical Science, Tokai University School of Medicine, Isehara
| | | | - Yasuko Ichikawa
- Department of Internal Medicine, Laboratory for Structure and Function Research, Isehara, Japan
| | | | - Toshio Miyata
- Molecular and Cellular Nephrology, Institute of Medical Science, Tokai University School of Medicine, Isehara
- Department of Internal Medicine, Laboratory for Structure and Function Research, Isehara, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo
| | | | - Kiyoshi Kurokawa
- Molecular and Cellular Nephrology, Institute of Medical Science, Tokai University School of Medicine, Isehara
- Department of Internal Medicine, Laboratory for Structure and Function Research, Isehara, Japan
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3
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Fuessl M, Reinders J, Oefner PJ, Heinze J, Schrempf A. Selenophosphate synthetase in the male accessory glands of an insect without selenoproteins. JOURNAL OF INSECT PHYSIOLOGY 2014; 71:46-51. [PMID: 25308180 DOI: 10.1016/j.jinsphys.2014.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 09/28/2014] [Accepted: 09/30/2014] [Indexed: 06/04/2023]
Abstract
Selenoproteins (containing the 21st proteinogenic amino acid selenocysteine) play important roles throughout all domains of life. Surprisingly, a number of taxa have small selenoproteomes, and Hymenopteran insects appear to have fully lost selenoproteins. Nevertheless, their genomes contain genes for several proteins of the selenocysteine insertion machinery, including selenophosphate synthetase 1 (SELD/SPS1). At present, it is unknown whether this enzyme has a selenoprotein-independent function, and whether the gene is actually translated into a protein in Hymenoptera. Here, we report that SELD/SPS1 is present as a protein in the accessory glands of males of the ant Cardiocondyla obscurior. It appears to be more abundant in the glands of winged disperser males than in those of wingless, local fighter males. Mating increases the lifespan and fecundity of queens in C. obscurior, and mating with winged males has a stronger effect on queen fitness than mating with a wingless male. SELD/SPS 1 has been suggested to play an important role in oxidative stress defense, and might therefore be involved in the life-prolonging effect of mating.
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Affiliation(s)
- Marion Fuessl
- Biologie I, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - Jörg Reinders
- Institute of Functional Genomics, University of Regensburg, Josef-Engert-Str. 9, D-93051 Regensburg, Germany
| | - Peter J Oefner
- Institute of Functional Genomics, University of Regensburg, Josef-Engert-Str. 9, D-93051 Regensburg, Germany
| | - Jürgen Heinze
- Biologie I, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - Alexandra Schrempf
- Biologie I, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany.
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Fitzpatrick E, Cotoi C, Quaglia A, Sakellariou S, Ford-Adams ME, Hadzic N. Hepatopathy of Mauriac syndrome: a retrospective review from a tertiary liver centre. Arch Dis Child 2014; 99:354-7. [PMID: 24412980 DOI: 10.1136/archdischild-2013-304426] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Mauriac syndrome is characterised by growth failure, cushingoid appearance and hepatomegaly which occurs in patients with insulin dependent diabetes and was first described shortly after the introduction of insulin as a treatment for the condition. OBJECTIVE To describe the clinical features, histological findings and outcome of young people with glycogenic hepatopathy, the hepatic manifestation of Mauriac syndrome (MS). DESIGN Retrospective cohort study. PATIENTS Young people with glycogenic hepatopathy. SETTING Tertiary paediatric hepatology unit. RESULTS Thirty-one young people (16 M), median age of 15.1 years (IQR 14-16.2) presented within the study period. Median age of diagnosis of diabetes was 10 years (IQR 8-11). Median insulin requirement was 1.33 units/kg/day; median HbA1c was 96.7 mmol/mol (IQR 84.7-112.0). Growth was impaired: median height z-score was -1.01 (-1.73 to 0.4) and median body mass index (BMI) z-score was 0.28 (-0.12 to 0.67). Hepatomegaly was universal with splenomegaly in 16%. Transaminases were abnormal with a median aspartate aminotransferase (AST) of 76 IU/L and gamma glutamyltransferase of 71 IU/L. Liver biopsy was undertaken in 19 (61%). All showed enlarged hepatocytes with clear cytoplasm with glycogenated nuclei in 17. Steatosis was present in the majority. Inflammation was present in 8 (42%). Fibrosis was seen in 14 (73%) and was generally mild though 2 had bridging fibrosis. Megamitochondria were described in 7. Presence of megamitochondria correlated with AST elevation (p=0.026) and fibrosis on biopsy (p=0.007). At follow-up 17 children had normal or improved transaminases, in 13 there was no change. Transaminases followed the trend of the child's HbA1c. CONCLUSIONS Despite modern insulin regimens and monitoring in children with type 1 diabetes, MS still exists. Significant steatosis, inflammation and fibrosis were all seen in liver biopsies.
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Affiliation(s)
- E Fitzpatrick
- Paediatric Liver, GI and Nutrition Centre, King's College London School of Medicine at King's College Hospital, , London, UK
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5
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Gdynia G, Keith M, Kopitz J, Bergmann M, Fassl A, Weber ANR, George J, Kees T, Zentgraf HW, Wiestler OD, Schirmacher P, Roth W. Danger signaling protein HMGB1 induces a distinct form of cell death accompanied by formation of giant mitochondria. Cancer Res 2010; 70:8558-68. [PMID: 20959471 DOI: 10.1158/0008-5472.can-10-0204] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cells dying by necrosis release the high-mobility group box 1 (HMGB1) protein, which has immunostimulatory effects. However, little is known about the direct actions of extracellular HMGB1 protein on cancer cells. Here, we show that recombinant human HMGB1 (rhHMGB1) exerts strong cytotoxic effects on malignant tumor cells. The rhHMGB1-induced cytotoxicity depends on the presence of mitochondria and leads to fast depletion of mitochondrial DNA, severe damage of the mitochondrial proteome by toxic malondialdehyde adducts, and formation of giant mitochondria. The formation of giant mitochondria is independent of direct nuclear signaling events, because giant mitochondria are also observed in cytoplasts lacking nuclei. Further, the reactive oxygen species scavenger N-acetylcysteine as well as c-Jun NH(2)-terminal kinase blockade inhibited the cytotoxic effect of rhHMGB1. Importantly, glioblastoma cells, but not normal astrocytes, were highly susceptible to rhHMGB1-induced cell death. Systemic treatment with rhHMGB1 results in significant growth inhibition of xenografted tumors in vivo. In summary, rhHMGB1 induces a distinct form of cell death in cancer cells, which differs from the known forms of apoptosis, autophagy, and senescence, possibly representing an important novel mechanism of specialized necrosis. Further, our findings suggest that rhHMGB1 may offer therapeutic applications in treatment of patients with malignant brain tumors.
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Affiliation(s)
- Georg Gdynia
- German Cancer Research Center, Institute of Pathology, University of Heidelberg, Heidelberg, Germany
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6
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Asher D, Finberg R. CAR might provide a survival signal for myocardial cells. J Cell Sci 2005; 118:5679; author reply 5679-80. [PMID: 16339965 DOI: 10.1242/jcs.02747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
MESH Headings
- Animals
- Cell Line
- Coxsackie and Adenovirus Receptor-Like Membrane Protein
- Embryo, Mammalian/cytology
- Embryo, Mammalian/metabolism
- Embryo, Mammalian/ultrastructure
- Endothelial Cells/cytology
- Endothelial Cells/metabolism
- Endothelial Cells/ultrastructure
- Fetal Death/genetics
- Fetal Death/metabolism
- Gene Expression Regulation, Developmental
- Genomic Library
- Heart/embryology
- Heart/growth & development
- Heart Defects, Congenital/genetics
- Heart Defects, Congenital/metabolism
- Mice
- Mice, Knockout
- Myocytes, Cardiac/pathology
- Myocytes, Cardiac/ultrastructure
- Myofibrils/pathology
- Myofibrils/ultrastructure
- Receptors, Virus/deficiency
- Receptors, Virus/genetics
- Receptors, Virus/metabolism
- Receptors, Virus/physiology
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7
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Bonini P, Cicconi S, Cardinale A, Vitale C, Serafino AL, Ciotti MT, Marlier LNJL. Oxidative stress induces p53-mediated apoptosis in glia: p53 transcription-independent way to die. J Neurosci Res 2004; 75:83-95. [PMID: 14689451 DOI: 10.1002/jnr.10822] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Oxidative stress has been implicated in the pathogenesis of stroke, traumatic brain injuries, and neurodegenerative diseases affecting both neuronal and glial cells in the central nervous system (CNS). The tumor suppressor protein p53 plays a pivotal function in neuronal apoptosis triggered by oxidative stress. We investigated the role of p53 and related molecular mechanisms that support oxidative stress-induced apoptosis in glia. For this purpose, we exposed C6 glioma cells and primary cultures of rat cortical astrocytes to an H(2)O(2)-induced oxidative stress protocol followed by a recovery period. We evaluated the effects of pifithrin-alpha (PF-alpha), which has been reported to protect neurons from ischemic insult by specifically inhibiting p53 DNA-binding activity. Strikingly, PF-alpha was unable to prevent oxidative stress-induced astrocyte apoptosis. We demonstrate that p53 is able to mediate an apoptotic response by direct signaling at mitochondria, despite its transcriptional activity. The z-VAD-fmk-sensitive apoptotic response requires a caspase-dependent MDM-2 degradation, leading to p53 mitochondrial targeting accompanied by cytochrome c release and nucleosomal fragmentation.
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Affiliation(s)
- Paolo Bonini
- Department of Internal Medicine, University of Rome Tor Vergata, Rome, Italy
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8
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Mattiasson G. Flow cytometric analysis of isolated liver mitochondria to detect changes relevant to cell death. ACTA ACUST UNITED AC 2004; 60:145-54. [PMID: 15290715 DOI: 10.1002/cyto.a.20024] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Mitochondria are key players in many forms of cell death, and mitochondrial production of reactive oxygen species (ROS), membrane depolarization, permeability changes, and release of apoptogenic proteins are involved in these processes. Flow cytometric analysis of isolated mitochondria enables parallel analysis of mitochondrial structure and function in individual mitochondria, and small mitochondrial samples are sufficient for analysis. This article describes a well-characterized protocol for flow cytometric analysis of isolated liver mitochondria that can be used to detect mitochondrial alterations relevant to cell death. METHODS Fluorescent probes were used to selectively stain mitochondria (nonyl acridine orange), and to measure membrane potential (tetramethylrhodamine-methyl-ester, 1,1',3,3,3',3'-hexamethylindodicarbocyanine-iodide), as well as production of ROS (2',7'-dichlorodihydrofluorescein-diacetate). Calcium-induced mitochondrial swelling was detected as a decrease in SSC. To ensure optimal concentrations of all probes, the effect on mitochondrial respiration was evaluated. RESULTS This protocol can be used to determine the purity of the mitochondrial preparation, to detect calcium-induced morphological changes, small mitochondrial de- and hyperpolarizations, as well as physiological changes in ROS generation. CONCLUSIONS Flow cytometry is a very useful tool to simultaneously analyze several mitochondrial parameters that are important in the induction of mitochondria-mediated cell death.
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Affiliation(s)
- Gustav Mattiasson
- Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, Lund University, Lund, Sweden.
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9
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Mattiasson G, Friberg H, Hansson M, Elmér E, Wieloch T. Flow cytometric analysis of mitochondria from CA1 and CA3 regions of rat hippocampus reveals differences in permeability transition pore activation. J Neurochem 2003; 87:532-44. [PMID: 14511130 DOI: 10.1046/j.1471-4159.2003.02026.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Mitochondria are important in the pathophysiology of several neurodegenerative diseases, and mitochondrial production of reactive oxygen species (ROS), membrane depolarization, permeability changes and release of apoptogenic proteins are involved in these processes. Following brain insults, cell death often occurs in discrete regions of the brain, such as the subregions of the hippocampus. To analyse mitochondrial structure and function in such subregions, only small amounts of mitochondria are available. We developed a protocol for flow cytometric analysis of very small samples of isolated brain mitochondria, and analysed mitochondrial swelling and formation of ROS in mitochondria from the CA1 and CA3 regions of the hippocampus. Calcium-induced mitochondrial swelling was measured, and fluorescent probes were used to selectively stain mitochondria (nonyl acridine orange), to measure membrane potential (tetramethylrhodamine-methyl-ester, 1,1',3,3,3',3'-hexamethylindodicarbocyanine-iodide) and to measure production of ROS (2',7'-dichlorodihydrofluorescein-diacetate). We found that formation of ROS and mitochondrial permeability transition pore activation were higher in mitochondria from the CA1 than from the CA3 region, and propose that differences in mitochondrial properties partly underlie the selective vulnerability of the CA1 region to brain insults. We also conclude that flow cytometry is a useful tool to analyse the role of mitochondria in cell death processes.
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Affiliation(s)
- Gustav Mattiasson
- Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, Lund University, Lund, Sweden.
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10
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Mattiasson G, Shamloo M, Gido G, Mathi K, Tomasevic G, Yi S, Warden CH, Castilho RF, Melcher T, Gonzalez-Zulueta M, Nikolich K, Wieloch T. Uncoupling protein-2 prevents neuronal death and diminishes brain dysfunction after stroke and brain trauma. Nat Med 2003; 9:1062-8. [PMID: 12858170 DOI: 10.1038/nm903] [Citation(s) in RCA: 401] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2003] [Accepted: 06/25/2003] [Indexed: 01/09/2023]
Abstract
Whereas uncoupling protein 1 (UCP-1) is clearly involved in thermogenesis, the role of UCP-2 is less clear. Using hybridization, cloning techniques and cDNA array analysis to identify inducible neuroprotective genes, we found that neuronal survival correlates with increased expression of Ucp2. In mice overexpressing human UCP-2, brain damage was diminished after experimental stroke and traumatic brain injury, and neurological recovery was enhanced. In cultured cortical neurons, UCP-2 reduced cell death and inhibited caspase-3 activation induced by oxygen and glucose deprivation. Mild mitochondrial uncoupling by 2,4-dinitrophenol (DNP) reduced neuronal death, and UCP-2 activity was enhanced by palmitic acid in isolated mitochondria. Also in isolated mitochondria, UCP-2 shifted the release of reactive oxygen species from the mitochondrial matrix to the extramitochondrial space. We propose that UCP-2 is an inducible protein that is neuroprotective by activating cellular redox signaling or by inducing mild mitochondrial uncoupling that prevents the release of apoptogenic proteins.
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Abstract
Mitochondria are both morphologically and functionally diverse, and this variety is thought to have important biological ramifications. The development of methods to probe the properties of individual mitochondria is therefore of utmost importance. Recent advances have been made using in situ microscopy techniques and methods to investigate isolated mitochondria, including flow cytometry, capillary electrophoresis, patch-clamping and optical trapping. Such techniques have been used to study metabolism, mitochondrial calcium homeostasis, mitochondrial membrane potential, apoptosis, and other properties.
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Affiliation(s)
- Kathryn M Fuller
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA
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12
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Abstract
Mitochondria undergo structural changes simultaneously with their functional changes in both physiological and pathological conditions. These structural changes of mitochondria are classified into two categories: simple swelling and the formation of megamitochondria (MG). Data have been accumulated to indicate that free radicals play a crucial role in the mechanism of the MG formation induced by various experimental conditions which are apparently various. These include ethanol-, chloramphenicol- and hydrazine-induced MG formation. Involvement of free radicals in the mechanism of MG formation is showed by the fact that MG formation is successfully suppressed by free radical scavengers such as alpha-tocopherol, coenzyme Q(10), and 4-OH-TEMPO. Detailed mechanisms and pathophysiological meanings of MG formation still remain to be investigated. However, a body of evidence strongly suggests that enormous changes in physicochemical and biochemical properties of the mitochondrial membranes during MG formation take place and these changes are favorable for membrane fusion. A recent report showed that continous exposure of cells with MG to free radicals induces apoptosis, finding which suggests that MG formation is an adaptative process to unfavorable environments at the level of intracellular organelles. Mitochondria try to decrease intracellular reactive oxygen species (ROS) levels by decreasing the consume of oxygen via MG formation. If mitochondria succeed to suppress intracellular ROS levels, MG return to normal both structurally and functionally, and they restore the ability to actively synthesize ATP. If cells are additionally exposed to excess amounts of free radicals, MG become swollen, membrane potential of mitochondria (DeltaPsim) decreases, cytochrome c is released from mitochondria, leading to activation of caspases and apoptosis is induced.
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Affiliation(s)
- T Wakabayashi
- Department of Cell Biology and Molecular Pathology, Medical University of Gdansk, Gdansk, Poland.
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13
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Ip SP, Chan YW, Che CT, Leung PS. Effect of chronic hypoxia on glutathione status and membrane integrity in the pancreas. Pancreatology 2002; 2:34-9. [PMID: 12120004 DOI: 10.1159/000049446] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Our recent study has shown that chronic hypoxia could upregulate significantly a local renin-angiotensin system in the pancreas. The activation of such a local renin-angiotensin system may provide an alternate mechanism that leads to the generation of reactive radical species in the pancreas during chronically hypoxic exposure. The present study aims at elucidating the antioxidant status in the pancreas during varying degrees of chronic hypoxia. METHODS Sprague-Dawley rats were exposed to an isobaric hypoxic (10% oxygen) chamber for a period up to 28 days. The glutathione status and membrane integrity of the pancreas were studied with a time course of chronic hypoxia (3, 7, 14, 21 and 28 days). The effect of chronic hypoxia on changes of oxidative states in the pancreas was assessed based on the measurements of glutathione, malondialdehyde, alpha-amylase and DNA fragmentation using biochemical assays. RESULTS Pancreatic glutathione was decreased drastically after 3-day hypoxia and its level was almost completely recovered after 7-day hypoxia. Malondialdehyde was not affected while DNA fragmentation was increased significantly in a time-dependent manner during the course of chronic hypoxia. Membrane integrity of the pancreatic cells was improved, as evidenced by the decrease of plasma alpha-amylase during the time-course study of chronic hypoxia. CONCLUSION Pancreatic glutathione was depleted only in the early period of chronic hypoxia followed by a rapid recovery, suggesting that adaptive response of the pancreas may occur during chronic hypoxia. The enhancement of glutathione-dependent antioxidant capacity during chronic hypoxia prevented oxidative damage to the membrane of the pancreatic cells.
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Affiliation(s)
- S P Ip
- School of Chinese Medicine, Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR
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14
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Agostinucci K, Manfredi T, Cosmas A, Martin K, Han S, Wu D, Sastre J, Meydani S, Meydani M. Vitamin E and Age Alter Liver Mitochondrial Morphometry. ACTA ACUST UNITED AC 2002. [DOI: 10.1089/10945450260195612] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- K. Agostinucci
- Exercise Science Laboratory, University of Rhode Island, Kingston, Rhode Island
| | - T.G. Manfredi
- Exercise Science Laboratory, University of Rhode Island, Kingston, Rhode Island
| | - A. Cosmas
- School of Allied Health Professions, University of Connecticut, Storrs, Connecticut
| | - K. Martin
- JM USDA-Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts
| | - S.N. Han
- JM USDA-Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts
| | - D. Wu
- JM USDA-Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts
| | - J. Sastre
- Department of Pharmacy, University of Valencia, Valencia, Spain
| | - S.N. Meydani
- JM USDA-Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts
| | - M. Meydani
- JM USDA-Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts
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15
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Hussain SM, Frazier JM. In vitro toxicity assessment of a new series of high energy compounds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2001; 274:151-160. [PMID: 11453292 DOI: 10.1016/s0048-9697(01)00737-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Hydrazine is an aircraft fuel and propellant used by the US Air Force. Due to its toxicity the Propulsion Directorate of the Air Force Research Laboratory (AFRL/PR) has investigated alternative chemicals to replace hydrazine. AFRL/PR has synthesized a series of high energy chemicals (HECs), primarily hydrazine derivatives and amino containing compounds such as hydrazinium nitrate (HZN), 2-hydroxyethyl-hydrazine nitrate (HEHN), diethyl hydrazine nitrate (DEHN), ethanolamine nitrate (EAN), histamine dinitrate (HDN) and methoxylamine nitrate (MAN) to study as alternative chemical candidates. Although HECs are reliable constituents of powered propellant systems, they constitute an important class of toxic agents to which military and civilian personnel can be exposed. The current study was undertaken to examine the toxicity of HECs in primary hepatocytes in vitro. The effects of short-term exposure (4 h) of hepatocytes to HECs were investigated with reference to viability, mitochondrial function and oxidative stress markers. The results showed a decrease in mitochondrial activity, increase in lactate dehydrogenase (LDH) leakage and depletion of reduced glutathione (GSH) levels. The levels of reactive oxygen species (ROS) increased dose dependently in HZN, MAN and HDN exposed cells. However, there was no induction of ROS generation in EAN, DEHN and HEHN exposed cells. Depletion of GSH in hepatocytes by buthionine sulfoximine (BSO) prior to exposure to HZN increased its toxicity. The results suggest that at least one mechanism of HEC toxicity is mediated through oxidative stress.
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Affiliation(s)
- S M Hussain
- Air Force Research Laboratory, HEST, Wright-Patterson Air Force Base, OH 45433-7400, USA
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