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Kim JS, Lee S, Kim WK, Han BS. Mitochondrial transplantation: an overview of a promising therapeutic approach. BMB Rep 2023; 56:488-495. [PMID: 37679296 PMCID: PMC10547968 DOI: 10.5483/bmbrep.2023-0098] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/02/2023] [Accepted: 09/04/2023] [Indexed: 02/06/2024] Open
Abstract
Mitochondrial transplantation is a promising therapeutic approach for the treatment of mitochondrial diseases caused by mutations in mitochondrial DNA, as well as several metabolic and neurological disorders. Animal studies have shown that mitochondrial transplantation can improve cellular energy metabolism, restore mitochondrial function, and prevent cell death. However, challenges need to be addressed, such as the delivery of functional mitochondria to the correct cells in the body, and the long-term stability and function of the transplanted mitochondria. Researchers are exploring new methods for mitochondrial transplantation, including the use of nanoparticles or CRISPR gene editing. Mechanisms underlying the integration and function of transplanted mitochondria are complex and not fully understood, but research has revealed some key factors that play a role. While the safety and efficacy of mitochondrial transplantation have been investigated in animal models and human trials, more research is needed to optimize delivery methods and evaluate long-term safety and efficacy. Clinical trials using mitochondrial transplantation have shown mixed results, highlighting the need for further research in this area. In conclusion, although mitochondrial transplantation holds significant potential for the treatment of various diseases, more work is needed to overcome challenges and evaluate its safety and efficacy in human trials. [BMB Reports 2023; 56(9): 488-495].
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Affiliation(s)
- Ji Soo Kim
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Functional Genomics, University of Science and Technology (UST) of Korea, Daejeon 34113, Korea
| | - Seonha Lee
- Department of Functional Genomics, University of Science and Technology (UST) of Korea, Daejeon 34113, Korea
- Biodefense Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
| | - Won-Kon Kim
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Functional Genomics, University of Science and Technology (UST) of Korea, Daejeon 34113, Korea
| | - Baek-Soo Han
- Department of Functional Genomics, University of Science and Technology (UST) of Korea, Daejeon 34113, Korea
- Biodefense Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
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2
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Kim JS, Lee S, Kim WK, Han BS. Mitochondrial transplantation: an overview of a promising therapeutic approach. BMB Rep 2023; 56:488-495. [PMID: 37679296 PMCID: PMC10547968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/02/2023] [Accepted: 09/04/2023] [Indexed: 09/09/2023] Open
Abstract
Mitochondrial transplantation is a promising therapeutic approach for the treatment of mitochondrial diseases caused by mutations in mitochondrial DNA, as well as several metabolic and neurological disorders. Animal studies have shown that mitochondrial transplantation can improve cellular energy metabolism, restore mitochondrial function, and prevent cell death. However, challenges need to be addressed, such as the delivery of functional mitochondria to the correct cells in the body, and the long-term stability and function of the transplanted mitochondria. Researchers are exploring new methods for mitochondrial transplantation, including the use of nanoparticles or CRISPR gene editing. Mechanisms underlying the integration and function of transplanted mitochondria are complex and not fully understood, but research has revealed some key factors that play a role. While the safety and efficacy of mitochondrial transplantation have been investigated in animal models and human trials, more research is needed to optimize delivery methods and evaluate long-term safety and efficacy. Clinical trials using mitochondrial transplantation have shown mixed results, highlighting the need for further research in this area. In conclusion, although mitochondrial transplantation holds significant potential for the treatment of various diseases, more work is needed to overcome challenges and evaluate its safety and efficacy in human trials. [BMB Reports 2023; 56(9): 488-495].
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Affiliation(s)
- Ji Soo Kim
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Functional Genomics, University of Science and Technology (UST) of Korea, Daejeon 34113, Korea
| | - Seonha Lee
- Department of Functional Genomics, University of Science and Technology (UST) of Korea, Daejeon 34113, Korea
- Biodefense Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
| | - Won-Kon Kim
- Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Functional Genomics, University of Science and Technology (UST) of Korea, Daejeon 34113, Korea
| | - Baek-Soo Han
- Department of Functional Genomics, University of Science and Technology (UST) of Korea, Daejeon 34113, Korea
- Biodefense Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
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3
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Affiliation(s)
- Teresa Summavielle
- Addiction Biology Group, IBMC-Instituto de Biologia Molecular e Celular, Porto, Portugal, Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal Laboratory Animal Science, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal Laboratory Animal Science, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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4
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Affiliation(s)
- Philip G Morgan
- Department of Anesthesiology and Pain Medicine, Seattle Children's Research Institute, University of Washington, Seattle, Washington, Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, Washington
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5
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Jagannathan R, Thapa D, Nichols CE, Shepherd DL, Stricker JC, Croston TL, Baseler WA, Lewis SE, Martinez I, Hollander JM. Translational Regulation of the Mitochondrial Genome Following Redistribution of Mitochondrial MicroRNA in the Diabetic Heart. ACTA ACUST UNITED AC 2015; 8:785-802. [PMID: 26377859 DOI: 10.1161/circgenetics.115.001067] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 09/01/2015] [Indexed: 01/05/2023]
Abstract
BACKGROUND Cardiomyocytes are rich in mitochondria which are situated in spatially distinct subcellular regions, including those under the plasma membrane, subsarcolemmal mitochondria, and those between the myofibrils, interfibrillar mitochondria. We previously observed subpopulation-specific differences in mitochondrial proteomes following diabetic insult. The objective of this study was to determine whether mitochondrial genome-encoded proteins are regulated by microRNAs inside the mitochondrion and whether subcellular spatial location or diabetes mellitus influences the dynamics. METHODS AND RESULTS Using microarray technology coupled with cross-linking immunoprecipitation and next generation sequencing, we identified a pool of mitochondrial microRNAs, termed mitomiRs, that are redistributed in spatially distinct mitochondrial subpopulations in an inverse manner following diabetic insult. Redistributed mitomiRs displayed distinct interactions with the mitochondrial genome requiring specific stoichiometric associations with RNA-induced silencing complex constituents argonaute-2 (Ago2) and fragile X mental retardation-related protein 1 (FXR1) for translational regulation. In the presence of Ago2 and FXR1, redistribution of mitomiR-378 to the interfibrillar mitochondria following diabetic insult led to downregulation of mitochondrially encoded F0 component ATP6. Next generation sequencing analyses identified specific transcriptome and mitomiR sequences associated with ATP6 regulation. Overexpression of mitomiR-378 in HL-1 cells resulted in its accumulation in the mitochondrion and downregulation of functional ATP6 protein, whereas antagomir blockade restored functional ATP6 protein and cardiac pump function. CONCLUSIONS We propose mitomiRs can translationally regulate mitochondrially encoded proteins in spatially distinct mitochondrial subpopulations during diabetes mellitus. The results reveal the requirement of RNA-induced silencing complex constituents in the mitochondrion for functional mitomiR translational regulation and provide a connecting link between diabetic insult and ATP synthase function.
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Affiliation(s)
- Rajaganapathi Jagannathan
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - Dharendra Thapa
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - Cody E Nichols
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - Danielle L Shepherd
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - Janelle C Stricker
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - Tara L Croston
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - Walter A Baseler
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - Sara E Lewis
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - Ivan Martinez
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown
| | - John M Hollander
- From the Department of Human Performances, Division of Exercise Physiology (R.J., D.T., C.E.N., D.L.S., J.C.S., T.L.C., W.A.B., S.E.L., J.M.H.), Center for Cardiovascular and Respiratory Sciences (R.J., D.T., C.E.N., D.L.S., T.L.C., W.A.B., S.E.L., J.M.H.), Department of Microbiology, Immunology and Cell Biology (I.M.), and Mary Babb Randolph Cancer Center (I.M.), West Virginia University School of Medicine, Morgantown.
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Gorgun FM, Zhuo M, Singh S, Englander EW. Neuroglobin mitigates mitochondrial impairments induced by acute inhalation of combustion smoke in the mouse brain. Inhal Toxicol 2015; 26:361-9. [PMID: 24730682 DOI: 10.3109/08958378.2014.902147] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT Acute inhalation of combustion smoke adversely affects brain homeostasis and energy metabolism. We previously showed that overexpressed neuroglobin (Ngb), neuron specific globin protein, attenuates the formation of smoke inhalation-induced oxidative DNA damage, in vivo, in the mouse brain, while others reported protection by Ngb in diverse models of brain injury, mainly involving oxidative stress and hypoxic/ischemic insults. OBJECTIVE To determine to what extent elevated Ngb ameliorates post smoke-inhalation brain bioenergetics and homeostasis in Ngb overexpressing transgenic mouse. METHODS Smoke inhalation induced changes in bioenergetics were measured in the wild type and Ngb transgene mouse brain. Modulations of mitochondrial respiration were analyzed using the Seahorse XF24 flux analyzer and changes in cytoplasmic energy metabolism were assessed by measuring enzymatic activities and lactate in the course of post smoke recovery. RESULTS Cortical mitochondria from Ngb transgene, better maintained ATP synthesis-linked oxygen consumption and unlike wild type mitochondria did not increase futile oxygen consumption feeding the proton leak, reflecting lesser smoke-induced mitochondrial compromise. Measurements revealed lesser reduction of mitochondrial ATP content and lesser compensatory increases in cytosolic energy metabolism, involving pyruvate kinase and lactate dehydrogenase activities as well as cytosolic lactate levels. Additionally, induction of c-Fos, the early response gene and key neuronal stress sensor, was attenuated in Ngb transgene compared to wild type brain after smoke. CONCLUSION Considered together, these differences reflect lesser perturbations produced by acute inhalation of combustion smoke in the Ngb overexpressing mouse, suggesting that Ngb mitigates mitochondrial dysfunction and neurotoxicity and raises the threshold of smoke inhalation-induced brain injury.
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Affiliation(s)
- Falih Murat Gorgun
- Department of Surgery, University of Texas Medical Branch , Galveston, TX , USA
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7
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Shen J, Du T, Wang X, Duan C, Gao G, Zhang J, Lu L, Yang H. α-Synuclein amino terminus regulates mitochondrial membrane permeability. Brain Res 2014; 1591:14-26. [PMID: 25446002 DOI: 10.1016/j.brainres.2014.09.046] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 09/05/2014] [Accepted: 09/19/2014] [Indexed: 12/22/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative movement disorder affecting an increasing number of elderly. Various studies have shown that mitochondrial dysfunction and abnormal protein aggregation are two major contributors to the progression of PD. The N terminus of α-synuclein (α-Syn/N), which adopts an α-helical conformation upon lipid binding, is essential for membrane interaction; yet its role in mitochondria remains poorly defined. A functional characterization of the α-Syn N-terminal domain and investigation of its effect on mitochondrial membrane permeability were undertaken in this study. α-Syn/N and α-Syn/delN (amino acids 1-65 and 61-140, respectively) constructs were overexpressed in dopaminergic MN9D cells and primary cortical neurons. A decrease in cell viability was observed in cells transfected with α-Syn/N but not α-Syn/delN. In addition, an α-Syn/N-induced increase in the level of intracellular reactive oxygen species, alteration in mitochondrial morphology, and decrease in mitochondrial membrane potential were accompanied by the activation of mitochondrial permeability transition pores (mPTP). These changes were also associated with a decline in mitochondrial cardiolipin content and interaction with the voltage-dependent anion channel and adenine nucleotide translocator in the mitochondrial membrane. The activation of mPTPs and reduction in cell viability were partially reversed by bongkrekic acid, an inhibitor of adenine nucleotide translocator (ANT), suggesting that the interaction between α-Syn and ANT promoted mPTP activation and was toxic to cells. BKA treatment reduced interaction of α-Syn/N with ANT and VDAC. These results suggest that the N terminus of α-Syn is essential for the regulation of mitochondrial membrane permeability and is a likely factor in the neurodegeneration associated with PD.
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Affiliation(s)
- Jiamei Shen
- Center for Parkinson׳s Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Department of Neurobiology Capital Medical University, Beijing 100069, China
| | - Tingting Du
- Center for Parkinson׳s Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Department of Neurobiology Capital Medical University, Beijing 100069, China
| | - Xue Wang
- Center for Parkinson׳s Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Department of Neurobiology Capital Medical University, Beijing 100069, China
| | - Chunli Duan
- Center for Parkinson׳s Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Department of Neurobiology Capital Medical University, Beijing 100069, China
| | - Ge Gao
- Center for Parkinson׳s Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Department of Neurobiology Capital Medical University, Beijing 100069, China
| | - Jianliang Zhang
- Center for Parkinson׳s Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Department of Neurobiology Capital Medical University, Beijing 100069, China
| | - Lingling Lu
- Center for Parkinson׳s Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Department of Neurobiology Capital Medical University, Beijing 100069, China
| | - Hui Yang
- Center for Parkinson׳s Disease, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of the Ministry of Education, Department of Neurobiology Capital Medical University, Beijing 100069, China.
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Xanthoceraside ameliorates mitochondrial dysfunction contributing to the improvement of learning and memory impairment in mice with intracerebroventricular injection of aβ1-42. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:969342. [PMID: 24976855 PMCID: PMC4058193 DOI: 10.1155/2014/969342] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/04/2014] [Accepted: 04/18/2014] [Indexed: 02/07/2023]
Abstract
The effects of xanthoceraside on learning and memory impairment were investigated and the possible mechanism associated with the protection of mitochondria was also preliminarily explored in Alzheimer's disease (AD) mice model induced by intracerebroventricular (i.c.v.) injection of Aβ1-42. The results indicated that xanthoceraside (0.08–0.32 mg/kg) significantly improved learning and memory impairment in Morris water maze test and Y-maze test. Xanthoceraside significantly reversed the aberrant decrease of ATP levels and attenuated the abnormal increase of ROS levels both in the cerebral cortex and hippocampus in mice injected with Aβ1-42. Moreover, xanthoceraside dose dependently reversed the decrease of COX, PDHC, and KGDHC activity in isolated cerebral cortex mitochondria of the mice compared with Aβ1-42 injected model mice. In conclusion, xanthoceraside could improve learning and memory impairment, promote the function of mitochondria, decrease the production of ROS, and inhibit oxidative stress. The improvement effects on mitochondria may be through withstanding the damage of Aβ to mitochondrial respiratory chain and the key enzymes in Kreb's cycle. Therefore, the results from present study and previous study indicate that xanthoceraside could be a competitive candidate for the treatment of AD.
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Chang AHK, Sancheti H, Garcia J, Kaplowitz N, Cadenas E, Han D. Respiratory substrates regulate S-nitrosylation of mitochondrial proteins through a thiol-dependent pathway. Chem Res Toxicol 2014; 27:794-804. [PMID: 24716714 PMCID: PMC4033640 DOI: 10.1021/tx400462r] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
S-Nitrosylation is a reversible post-translational
modification
on cysteinyl thiols that can modulate the function of redox-sensitive
proteins. The S-nitrosylation of mitochondrial proteins has been shown
to regulate various mitochondrial activities involved in energy-transducing
systems and mitochondrion-driven apoptosis. In isolated rat brain
mitochondria, we demonstrate that mitochondrial protein S-nitrosylation
is regulated by respiratory substrates (glutamate/malate) through
a thiol-dependent pathway. Mitochondrial proteins become susceptible
to S-nitrosoglutathione (GSNO)-induced S-nitrosylation
in mitochondria with an oxidized environment (low glutathione (GSH),
NADH, and NADPH, and high GSSG, NAD+, and NADP+) caused by isolation of mitochondria using a discontinuous Percoll
gradient. Activation of mitochondrial respiration by respiratory substrates
leads to increased NAD(P)H and GSH levels, which in turn reduces mitochondrial
S-nitrosylated proteins. 1-Chloro-2,4-dinitrobenzene (CDNB), which
depletes mitochondrial GSH and inhibits the thioredoxin–thioredoxin
reductase system, prevented the denitrosylation of mitochondrial proteins
caused by respiratory substrate treatment. Using biotin-switch coupled
with LC-MS/MS, several mitochondrial proteins were identified as targets
of S-nitrosylation including adenine nucleotide translocase (ANT)
and voltage-dependent anion channel (VDAC), important components of
the mitochondria permeability transition pore (MPTP), as well as ATP
synthase. The S-nitrosylation of ATP synthase by GSNO was found to
inhibit its activity. These findings emphasize the importance of respiratory
substrates in regulating S-nitrosylation through a thiol-dependent
(GSH and/or thioredoxin) pathway, with implications for mitochondrial
bioenergetics and mitochondrion-driven apoptosis.
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Affiliation(s)
- Allen H K Chang
- Department of Pharmacology & Pharmaceutical Sciences, School of Pharmacy, University of Southern California , Los Angeles, California 90089, United States
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Van Bergen NJ, Blake RE, Crowston JG, Trounce IA. Oxidative phosphorylation measurement in cell lines and tissues. Mitochondrion 2014; 15:24-33. [DOI: 10.1016/j.mito.2014.03.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 03/06/2014] [Accepted: 03/10/2014] [Indexed: 01/01/2023]
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11
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Pandya JD, Nukala VN, Sullivan PG. Concentration dependent effect of calcium on brain mitochondrial bioenergetics and oxidative stress parameters. FRONTIERS IN NEUROENERGETICS 2013; 5:10. [PMID: 24385963 PMCID: PMC3866544 DOI: 10.3389/fnene.2013.00010] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 11/26/2013] [Indexed: 12/29/2022]
Abstract
Mitochondrial dysfunction following traumatic brain and spinal cord injury (TBI and SCI) plays a pivotal role in the development of secondary pathophysiology and subsequent neuronal cell death. Previously, we demonstrated a loss of mitochondrial bioenergetics in the first 24 h following TBI and SCI initiates a rapid and extensive necrotic event at the primary site of injury. Within the mitochondrial derived mechanisms, the cross talk and imbalance amongst the processes of excitotoxicity, Ca2+ cycling/overload, ATP synthesis, free radical production and oxidative damage ultimately lead to mitochondrial damage followed by neuronal cell death. Mitochondria are one of the important organelles that regulate intracellular calcium (Ca2+) homeostasis and are equipped with a tightly regulated Ca2+ transport system. However, owing to the lack of consensus and the link between downstream effects of calcium in published literature, we undertook a systematic in vitro study for measuring concentration dependent effects of calcium (100–1000 nmols/mg mitochondrial protein) on mitochondrial respiration, enzyme activities, reactive oxygen/nitrogen species (ROS/RNS) generation, membrane potential (ΔΨ) and oxidative damage markers in isolated brain mitochondria. We observed a dose- and time-dependent inhibition of mitochondrial respiration by calcium without influencing mitochondrial pyruvate dehydrogenase complex (PDHC) and NADH dehydrogenase (Complex I) enzyme activities. We observed dose-dependent decreased production of hydrogen peroxide and total ROS/RNS species generation by calcium and no significant changes in protein and lipid oxidative damage markers. These results may shed new light on the prevailing dogma of the direct effects of calcium on mitochondrial bioenergetics, free radical production and oxidative stress parameters that are primary regulatory mitochondrial mechanisms following neuronal injury.
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Affiliation(s)
- Jignesh D Pandya
- Department of Anatomy and Neurobiology, Spinal Cord and Brain Injury Research Center, University of Kentucky Lexington, KY, USA
| | - Vidya N Nukala
- Department of Anatomy and Neurobiology, Spinal Cord and Brain Injury Research Center, University of Kentucky Lexington, KY, USA
| | - Patrick G Sullivan
- Department of Anatomy and Neurobiology, Spinal Cord and Brain Injury Research Center, University of Kentucky Lexington, KY, USA
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Suh JH, Moreau R, Heath SHD, Hagen TM. Dietary supplementation with (R)-α-lipoic acid reverses the age-related accumulation of iron and depletion of antioxidants in the rat cerebral cortex. Redox Rep 2013; 10:52-60. [PMID: 15829111 DOI: 10.1179/135100005x21624] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Accumulation of divalent metal ions (e.g. iron and copper) has been proposed to contribute to heightened oxidative stress evident in aging and neurodegenerative disorders. To understand the extent of iron accumulation and its effect on antioxidant status, we monitored iron content in the cerebral cortex of F344 rats by inductively coupled plasma atomic emission spectrometry (ICP-AES) and found that the cerebral iron levels in 24-28-month-old rats were increased by 80% (p<0.01) relative to 3-month-old rats. Iron accumulation correlated with a decline in glutathione (GSH) and the GSH/GSSG ratio, indicating that iron accumulation altered antioxidant capacity and thiol redox state in aged animals. Because (R)-alpha-Lipoic acid (LA) is a potent chelator of divalent metal ions in vitro and also regenerates other antioxidants, we monitored whether feeding LA (0.2% [w/w]; 2 weeks) could lower cortical iron and improve antioxidant status. Results show that cerebral iron levels in old LA-fed animals were lower when compared to controls and were similar to levels seen in young rats. Antioxidant status and thiol redox state also improved markedly in old LA-fed rats versus controls. These results thus show that LA supplementation may be a means to modulate the age-related accumulation of cortical iron content, thereby lowering oxidative stress associated with aging.
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Affiliation(s)
- Jung H Suh
- Department Biochemistry and Biophysics, Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA
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13
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Barros Silva R, Santos NAG, Martins NM, Ferreira DAS, Barbosa F, Oliveira Souza VC, Kinoshita A, Baffa O, Del-Bel E, Santos AC. Caffeic acid phenethyl ester protects against the dopaminergic neuronal loss induced by 6-hydroxydopamine in rats. Neuroscience 2013; 233:86-94. [PMID: 23291456 DOI: 10.1016/j.neuroscience.2012.12.041] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 12/20/2012] [Accepted: 12/22/2012] [Indexed: 01/13/2023]
Abstract
Caffeic acid phenethyl ester (CAPE) is a botanical compound abundant in honeybees' propolis. It has anti-inflammatory, antiviral, antioxidant, immunomodulatory and antitumor properties. Its beneficial effects against neurodegenerative diseases, including Parkinson's disease, have also been suggested and some mechanisms have been proposed. Mitochondrial damage and oxidative stress are critical events in neurodegeneration. Release of cytochrome c from mitochondria to cytosol and the downstream activation of caspase-3 have been suggested as targets of the protective mechanism of CAPE. Most of the studies addressing the protective effect of CAPE have been performed in cell culture. This is the first study to demonstrate the protective effect of CAPE against the dopaminergic neuronal loss induced by 6-hydroxydopamine (6-OHDA) in rats. It also demonstrates, for the first time, the inhibitory effect of CAPE on mitochondrial permeability transition (MPT), a mediator of neuronal death that triggers cytochrome c release and caspase-3 activation. Scavenging of reactive oxygen species (ROS) and metal chelation was demonstrated in the brain-affected areas of the rats treated with 6-OHDA and CAPE. Additionally, we demonstrated that CAPE does not affect brain mitochondrial function. Based on these findings and on its ability to cross the blood-brain barrier, CAPE is a promising compound to treat Parkinson's and other neurodegenerative diseases.
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Affiliation(s)
- R Barros Silva
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Avenida do Café s/n, 14040-903 Ribeirão Preto, SP, Brazil
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14
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Satori CP, Kostal V, Arriaga EA. Review on recent advances in the analysis of isolated organelles. Anal Chim Acta 2012; 753:8-18. [PMID: 23107131 PMCID: PMC3484375 DOI: 10.1016/j.aca.2012.09.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 09/22/2012] [Accepted: 09/24/2012] [Indexed: 10/27/2022]
Abstract
The analysis of isolated organelles is one of the pillars of modern bioanalytical chemistry. This review describes recent developments on the isolation and characterization of isolated organelles both from living organisms and cell cultures. Salient reports on methods to release organelles focused on reproducibility and yield, membrane isolation, and integrated devices for organelle release. New developments on organelle fractionation after their isolation were on the topics of centrifugation, immunocapture, free flow electrophoresis, flow field-flow fractionation, fluorescence activated organelle sorting, laser capture microdissection, and dielectrophoresis. New concepts on characterization of isolated organelles included atomic force microscopy, optical tweezers combined with Raman spectroscopy, organelle sensors, flow cytometry, capillary electrophoresis, and microfluidic devices.
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Affiliation(s)
- Chad P Satori
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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15
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Tissue-specific splicing of an Ndufs6 gene-trap insertion generates a mitochondrial complex I deficiency-specific cardiomyopathy. Proc Natl Acad Sci U S A 2012; 109:6165-70. [PMID: 22474353 DOI: 10.1073/pnas.1113987109] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Mitochondrial complex I (CI) deficiency is the most common mitochondrial enzyme defect in humans. Treatment of mitochondrial disorders is currently inadequate, emphasizing the need for experimental models. In humans, mutations in the NDUFS6 gene, encoding a CI subunit, cause severe CI deficiency and neonatal death. In this study, we generated a CI-deficient mouse model by knockdown of the Ndufs6 gene using a gene-trap embryonic stem cell line. Ndufs6(gt/gt) mice have essentially complete knockout of the Ndufs6 subunit in heart, resulting in marked CI deficiency. Small amounts of wild-type Ndufs6 mRNA are present in other tissues, apparently due to tissue-specific mRNA splicing, resulting in milder CI defects. Ndufs6(gt/gt) mice are born healthy, attain normal weight and maturity, and are fertile. However, after 4 mo in males and 8 mo in females, Ndufs6(gt/gt) mice are at increased risk of cardiac failure and death. Before overt heart failure, Ndufs6(gt/gt) hearts show decreased ATP synthesis, accumulation of hydroxyacylcarnitine, but not reactive oxygen species (ROS). Ndufs6(gt/gt) mice develop biventricular enlargement by 1 mo, most pronounced in males, with scattered fibrosis and abnormal mitochondrial but normal myofibrillar ultrastructure. Ndufs6(gt/gt) isolated working heart preparations show markedly reduced left ventricular systolic function, cardiac output, and functional work capacity. This reduced energetic and functional capacity is consistent with a known susceptibility of individuals with mitochondrial cardiomyopathy to metabolic crises precipitated by stresses. This model of CI deficiency will facilitate studies of pathogenesis, modifier genes, and testing of therapeutic approaches.
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16
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Bumpus NN. Efavirenz and 8-hydroxyefavirenz induce cell death via a JNK- and BimEL-dependent mechanism in primary human hepatocytes. Toxicol Appl Pharmacol 2011; 257:227-34. [DOI: 10.1016/j.taap.2011.09.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/04/2011] [Accepted: 09/12/2011] [Indexed: 12/14/2022]
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17
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Lores-Arnaiz S, Bustamante J. Age-related alterations in mitochondrial physiological parameters and nitric oxide production in synaptic and non-synaptic brain cortex mitochondria. Neuroscience 2011; 188:117-24. [PMID: 21600964 DOI: 10.1016/j.neuroscience.2011.04.060] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 04/26/2011] [Accepted: 04/27/2011] [Indexed: 10/18/2022]
Abstract
Brain aging has been associated with mitochondrial dysfunction and changes in nitric oxide levels. The aim of this study was to evaluate the susceptibility of synaptic and non-synaptic mitochondria to aging-dependent dysfunction. State 3 respiratory rate and respiratory control were 43% and 33% decreased, respectively in brain cortex synaptosomes from 14-month-old animals, as compared with synaptosomes from 3-month-old mice. Respiratory rates were not significantly affected by aging in non-synaptic mitochondrial fractions. Mitochondrial dysfunction was associated with increases of 84% and 38% in H₂O₂ production rates in brain cortex synaptosomes and non-synaptic mitochondria, respectively, from 14-month-old mice, as compared with young animals. Synaptic mitochondria seem to be more susceptible to calcium insult in 14-month-old mice, as compared with non-synaptic mitochondria, as measured by response of both types of fractions to calcium-induced depolarization. With aging, nitric oxide (NO) production was 44% and 27% decreased both in synaptosomal and non-synaptic mitochondrial fractions, respectively. The results of this study suggest that with aging, mitochondrial function at the nerve terminals would be more susceptible to suffer alterations by the constant calcium changes occurring as a consequence of synaptic activity. Non-synaptic mitochondria would be more resistant to age-related dysfunction and oxidative damage.
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Affiliation(s)
- S Lores-Arnaiz
- Laboratory of Free Radical Biology, School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina.
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18
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Timmons MD, Bradley MA, Lovell MA, Lynn BC. Procedure for the isolation of mitochondria, cytosolic and nuclear material from a single piece of neurological tissue for high-throughput mass spectral analysis. J Neurosci Methods 2011; 197:279-82. [PMID: 21392528 DOI: 10.1016/j.jneumeth.2011.02.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2010] [Revised: 01/14/2011] [Accepted: 02/18/2011] [Indexed: 11/17/2022]
Abstract
The isolation of high-purity cellular biomacromolecules and sub-cellular organelles is an essential aspect to mass spectrometry based studies. Mitochondria are sub-cellular organelles that perform a central role in cellular energy production. Mitochondria are of great interest due to their potential to generate reactive oxygen species (ROS) and susceptibility to oxidative damage and subsequent functional impairment. Current methods of mitochondria isolation are optimized for respiratory-based studies that favor viability. Whereas, proteomic and lipidomics studies of mitochondria require procedures that optimize for purity and enrichment. We describe a procedure derived from previously established methods for the isolation of mitochondria, nuclear and cytosolic fractions from a neurological tissue sample. In addition to the isolation being of significant purity for mass spectral based '-omics' analysis, mitochondrial yields were routinely 500 μg per tissue wet weight, allowing multiple studies to be conducted from a single isolation procedure.
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Affiliation(s)
- Michael D Timmons
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0046, USA
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19
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Zhu Y, Duan C, Lü L, Gao H, Zhao C, Yu S, Uéda K, Chan P, Yang H. α-Synuclein overexpression impairs mitochondrial function by associating with adenylate translocator. Int J Biochem Cell Biol 2011; 43:732-41. [PMID: 21310263 DOI: 10.1016/j.biocel.2011.01.014] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 01/17/2011] [Accepted: 01/19/2011] [Indexed: 12/30/2022]
Abstract
α-Synuclein (α-syn), a protein involved in the pathogenesis of Parkinson's disease (PD), is known to accumulate in mitochondria, disrupt mitochondrial function. However, the molecular mechanisms that link these pathological responses have not been investigated. In rats overexpressing α-syn in the substantia nigra (SN) through adeno-associated virus (AAV) transduction, about 50% of tyrosine hydroxylase positive neurons were lost after 24 weeks. Overexpression of α-syn was also associated with morphological deformation of mitochondria and depolarization of the mitochondrial membrane potential (ΔΨm). Both co-immunoprecipitation and confocal microscopy demonstrated that mitochondrial α-syn associated with adenylate translocator (ANT), a component of the mitochondrial permeability transition pore (mPTP). The depolarization of ΔΨm was partially reversed in vitro by bongkrekic acid (BKA), an inhibitor of ANT, suggesting that the molecular association between α-syn and ANT facilitated ΔΨm depolarization. Concomitant with α-syn accumulation in mitochondria, abnormal mitochondrial morphology, ΔΨm depolarization, and loss of TH-positive neurons, there was a decrease in apoptosis-inducing factor (AIF) within the mitochondrial matrix, suggesting possible translocation to the cytosol. Our findings suggest that overexpression of α-syn may cause mitochondrial defects in dopaminergic neurons of the substantia nigra through an association with adenylate translocator and activation of mitochondria-dependent cell death pathways. Disruption of normal mitochondrial function may contribute to the loss of dopaminergic neurons in Parkinson's disease.
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Affiliation(s)
- Yuangang Zhu
- Beijing Institute for Neuroscience, Department of Neurobiology, Capital Medical University, Beijing Center of Neural Regeneration and Repair, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing 100069, China
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20
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Garcia J, Han D, Sancheti H, Yap LP, Kaplowitz N, Cadenas E. Regulation of mitochondrial glutathione redox status and protein glutathionylation by respiratory substrates. J Biol Chem 2010; 285:39646-54. [PMID: 20937819 PMCID: PMC3000945 DOI: 10.1074/jbc.m110.164160] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 09/17/2010] [Indexed: 11/06/2022] Open
Abstract
Brain and liver mitochondria isolated by a discontinuous Percoll gradient show an oxidized redox environment, which is reflected by low GSH levels and high GSSG levels and significant glutathionylation of mitochondrial proteins as well as by low NAD(P)H/NAD(P) values. The redox potential of brain mitochondria isolated by a discontinuous Percoll gradient method was calculated to be -171 mV based on GSH and GSSG concentrations. Immunoblotting and LC/MS/MS analysis revealed that succinyl-CoA transferase and ATP synthase (F(1) complex, α-subunit) were extensively glutathionylated; S-glutathionylation of these proteins resulted in a substantial decrease of activity. Supplementation of mitochondria with complex I or complex II respiratory substrates (malate/glutamate or succinate, respectively) increased NADH and NADPH levels, resulting in the restoration of GSH levels through reduction of GSSG and deglutathionylation of mitochondrial proteins. Under these conditions, the redox potential of brain mitochondria was calculated to be -291 mV. Supplementation of mitochondria with respiratory substrates prevented GSSG formation and, consequently, ATP synthase glutathionylation in response to H(2)O(2) challenges. ATP synthase appears to be the major mitochondrial protein that becomes glutathionylated under oxidative stress conditions. Glutathionylation of mitochondrial proteins is a major consequence of oxidative stress, and respiratory substrates are key regulators of mitochondrial redox status (as reflected by thiol/disulfide exchange) by maintaining mitochondrial NADPH levels.
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Affiliation(s)
- Jerome Garcia
- From the Department of Pharmacology & Pharmaceutical Sciences, School of Pharmacy and
| | - Derick Han
- the Research Center for Liver Disease, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
| | - Harsh Sancheti
- From the Department of Pharmacology & Pharmaceutical Sciences, School of Pharmacy and
| | - Li-Peng Yap
- From the Department of Pharmacology & Pharmaceutical Sciences, School of Pharmacy and
| | - Neil Kaplowitz
- the Research Center for Liver Disease, Keck School of Medicine, University of Southern California, Los Angeles, California 90089
| | - Enrique Cadenas
- From the Department of Pharmacology & Pharmaceutical Sciences, School of Pharmacy and
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21
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Lee HM, Hallberg LM, Greeley GH, Englander EW. Differential inhibition of mitochondrial respiratory complexes by inhalation of combustion smoke and carbon monoxide, in vivo, in the rat brain. Inhal Toxicol 2010; 22:770-7. [PMID: 20429857 DOI: 10.3109/08958371003770315] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Combustion smoke contains gases and particulates, which act via hypoxia and cytotoxicity producing mechanisms to injure cells and tissues. While carbon monoxide (CO) is the major toxicant in smoke, its toxicity is exacerbated in the presence of other compounds. Here, we examined modulations of mitochondrial and cytosolic energy metabolism by inhalation of combustion smoke versus CO, in vivo, in the rat brain. Measurements revealed reduced activities of respiratory chain (RC) complexes, with greater inhibition by smoke than equivalent CO in ambient air. In the case of RC complex IV, inhibition by CO and smoke was similar--suggesting that complex IV inhibition is primarily by the action of CO. In contrast, inhibition of complexes I and III was greater by smoke. Increases in cytosolic lactate dehydrogenase and pyruvate kinase activities accompanied inhibition of RC complexes, likely reflecting compensatory increases in cytosolic energy production. Together, the data provide new insights into the mechanisms of smoke inhalation-induced perturbations of brain energetics, which impact neuronal function and contribute to the development of neuropathologies in survivors of exposures to CO and combustion smoke.
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Affiliation(s)
- Heung M Lee
- Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555-1220, USA
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22
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Martins NM, Ferreira DAS, Carvalho Rodrigues MA, Cintra ACO, Santos NAG, Sampaio SV, Santos AC. Low-molecular-mass peptides from the venom of the Amazonian viper Bothrops atrox protect against brain mitochondrial swelling in rat: potential for neuroprotection. Toxicon 2010; 56:86-92. [PMID: 20338188 DOI: 10.1016/j.toxicon.2010.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 03/12/2010] [Accepted: 03/17/2010] [Indexed: 12/25/2022]
Abstract
The neurodegenerative diseases are important causes of morbidity and mortality in Western countries. Common mechanisms of toxicity involving mitochondrial damage have been suggested; however, a definitive treatment has not yet been found. Therefore, there has been great interest in the development of mitochondria-targeted protective compounds for the treatment of neuropathies. Animal toxins represent a promising source of new molecules with neuroprotective activity and potential to originate new drugs. We present here the effects of a low-molecular-mass peptides fraction (Ba-V) from Bothrops atrox snake venom, on rat brain mitochondrial function. Ba-V did not induce the mitochondrial swelling and moreover, was as effective as cyclosporin A (CsA) to inhibit the calcium/phosphate-induced swelling, which indicates its potential to prevent the mitochondrial permeability transition (MPT). The membrane electrochemical potential, the oxygen consumption during states-3 and -4 respirations as well as the respiratory control ratio (RCR) were not affected by Ba-V. Additionally, Ba-V did not induce reactive oxygen species (ROS) generation. Interestingly, Ba-V did not protect against the generation of ROS induced by t-BOH, which suggests a protection mechanism other than ROS scavenging. Given the important role of the mitochondrial damage and, more specifically, of MPT, in the development of neuropathies, Ba-V might be useful in the future strategies for the treatment of these diseases.
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Affiliation(s)
- N M Martins
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Av. do Café s/n, 14040-903 Ribeirão Preto SP, Brazil
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23
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Mitochondrial DNA toxicity in forebrain neurons causes apoptosis, neurodegeneration, and impaired behavior. Mol Cell Biol 2010; 30:1357-67. [PMID: 20065039 DOI: 10.1128/mcb.01149-09] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Mitochondrial dysfunction underlying changes in neurodegenerative diseases is often associated with apoptosis and a progressive loss of neurons, and damage to the mitochondrial genome is proposed to be involved in such pathologies. In the present study we designed a mouse model that allows us to specifically induce mitochondrial DNA toxicity in the forebrain neurons of adult mice. This is achieved by CaMKIIalpha-regulated inducible expression of a mutated version of the mitochondrial UNG DNA repair enzyme (mutUNG1). This enzyme is capable of removing thymine from the mitochondrial genome. We demonstrate that a continual generation of apyrimidinic sites causes apoptosis and neuronal death. These defects are associated with behavioral alterations characterized by increased locomotor activity, impaired cognitive abilities, and lack of anxietylike responses. In summary, whereas mitochondrial base substitution and deletions previously have been shown to correlate with premature and natural aging, respectively, we show that a high level of apyrimidinic sites lead to mitochondrial DNA cytotoxicity, which causes apoptosis, followed by neurodegeneration.
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24
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Ye B, Kroboth SL, Pu JL, Sims JJ, Aggarwal NT, McNally EM, Makielski JC, Shi NQ. Molecular identification and functional characterization of a mitochondrial sulfonylurea receptor 2 splice variant generated by intraexonic splicing. Circ Res 2009; 105:1083-93. [PMID: 19797704 DOI: 10.1161/circresaha.109.195040] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Cardioprotective pathways may involve a mitochondrial ATP-sensitive potassium (mitoK(ATP)) channel but its composition is not fully understood. OBJECTIVE We hypothesized that the mitoK(ATP) channel contains a sulfonylurea receptor (SUR)2 regulatory subunit and aimed to identify the molecular structure. METHODS AND RESULTS Western blot analysis in cardiac mitochondria detected a 55-kDa mitochondrial SUR2 (mitoSUR2) short form, 2 additional short forms (28 and 68 kDa), and a 130-kDa long form. RACE (Rapid Amplification of cDNA Ends) identified a 1.5-Kb transcript, which was generated by a nonconventional intraexonic splicing (IES) event within the 4th and 29th exons of the SUR2 mRNA. The translated product matched the predicted size of the 55-kDa short form. In a knockout mouse (SUR2KO), in which the SUR2 gene was disrupted, the 130-kDa mitoSUR2 was absent, but the short forms remained expressed. Diazoxide failed to induce increased fluorescence of flavoprotein oxidation in SUR2KO cells, indicating that the diazoxide-sensitive mitoK(ATP) channel activity was associated with 130-kDa-based channels. However, SUR2KO mice displayed similar infarct sizes to preconditioned wild type, suggesting a protective role for the remaining short form-based channels. Heterologous coexpression of the SUR2 IES variant and Kir6.2 in a K(+) transport mutant Escherichia coli strain permitted improved cell growth under acidic pH conditions. The SUR2 IES variant was localized to mitochondria, and removal of a predicted mitochondrial targeting sequence allowed surface expression and detection of an ATP-sensitive current when coexpressed with Kir6.2. CONCLUSIONS We identify a novel SUR2 IES variant in cardiac mitochondria and provide evidence that the variant-based channel can form an ATP-sensitive conductance and may contribute to cardioprotection.
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Affiliation(s)
- Bin Ye
- Department of Medicine, University of Wisconsin, Madison, WI 53706, USA
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25
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Zhou Q, Lam PY, Han D, Cadenas E. Activation of c-Jun-N-terminal kinase and decline of mitochondrial pyruvate dehydrogenase activity during brain aging. FEBS Lett 2009; 583:1132-40. [PMID: 19272379 DOI: 10.1016/j.febslet.2009.02.043] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2008] [Revised: 02/13/2009] [Accepted: 02/28/2009] [Indexed: 01/28/2023]
Abstract
Mitochondrial dysfunction is often associated with aging and neurodegeneration. c-Jun-N-terminal kinase (JNK) phosphorylation and its translocation to mitochondria increased as a function of age in rat brain. This was associated with a decrease of pyruvate dehydrogenase (PDH) activity upon phosphorylation of the E(1alpha) subunit of PDH. Phosphorylation of PDH is likely mediated by PDH kinase, the protein levels and activity of which increased with age. ATP levels were diminished, whereas lactic acid levels increased, thus indicating a shift toward anaerobic glycolysis. The energy transduction deficit due to impairment of PDH activity during aging may be associated with JNK signaling.
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Affiliation(s)
- Qiongqiong Zhou
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205-2186, USA
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26
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Lee HM, Reed J, Greeley GH, Englander EW. Impaired mitochondrial respiration and protein nitration in the rat hippocampus after acute inhalation of combustion smoke. Toxicol Appl Pharmacol 2008; 235:208-15. [PMID: 19133281 DOI: 10.1016/j.taap.2008.12.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 12/03/2008] [Accepted: 12/04/2008] [Indexed: 11/16/2022]
Abstract
Survivors of massive inhalation of combustion smoke endure critical injuries, including lasting neurological complications. We have previously reported that acute inhalation of combustion smoke disrupts the nitric oxide homeostasis in the rat brain. In this study, we extend our findings and report that a 30-minute exposure of awake rats to ambient wood combustion smoke induces protein nitration in the rat hippocampus and that mitochondrial proteins are a sensitive nitration target in this setting. Mitochondria are central to energy metabolism and cellular signaling and are critical to proper cell function. Here, analyses of the mitochondrial proteome showed elevated protein nitration in the course of a 24-hour recovery following exposure to smoke. Mass spectrometry identification of several significantly nitrated mitochondrial proteins revealed diverse functions and involvement in central aspects of mitochondrial physiology. The nitrated proteins include the ubiquitous mitochondrial creatine kinase, F1-ATP synthase alpha subunit, dihydrolipoamide dehydrogenase (E3), succinate dehydrogenase Fp subunit, and voltage-dependent anion channel (VDAC1) protein. Furthermore, acute exposure to combustion smoke significantly compromised the respiratory capacity of hippocampal mitochondria. Importantly, elevated protein nitration and reduced mitochondrial respiration in the hippocampus persisted beyond the time required for restoration of normal oxygen and carboxyhemoglobin blood levels after the cessation of exposure to smoke. Thus, the time frame for intensification of the various smoke-induced effects differs between blood and brain tissues. Taken together, our findings suggest that nitration of essential mitochondrial proteins may contribute to the reduction in mitochondrial respiratory capacity and underlie, in part, the brain pathophysiology after acute inhalation of combustion smoke.
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Affiliation(s)
- Heung M Lee
- Department of Surgery, University of Texas Medical Branch, Galveston, TX 77550, USA
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27
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Flatscher-Bader T, Wilce PA. Impact of alcohol abuse on protein expression of midkine and excitatory amino acid transporter 1 in the human prefrontal cortex. Alcohol Clin Exp Res 2008; 32:1849-58. [PMID: 18657127 DOI: 10.1111/j.1530-0277.2008.00754.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Alcoholism is associated with shrinkage of brain tissue and reduction in the number of neurons and dendritic arbors particularly in the prefrontal cortex. These changes correlate with the cognitive defects common in alcoholics. A recent study investigated the mRNA expression of selected genes in the prefrontal cortex and found that the levels of mRNA encoding the neurotrophic factor, midkine (MDK), and the excitatory amino acid transporter 1 (EAAT1) were significantly higher in alcoholics compared with nonalcoholic controls. This study aimed to investigate, whether the transcriptional changes observed result in alterations to protein expression. Additionally, the study aimed to expand our understanding of MDK and EAAT1 action by localizing their expression within morphologically and functionally distinct layers of this brain region. METHODS Quantitative changes in protein levels of MDK and EAAT1 were investigated in alcoholic and control cases using Western blots. Immunohistochemistry was utilized to localize proteins expression in formalin-fixed sagittal sections of the prefrontal cortex. RESULTS A marked increase was revealed in protein expression of both genes in the prefrontal cortex of chronic alcoholics. MDK-like immunofluorescence in alcoholic and control cases was present in nuclei throughout the prefrontal cortex and was particularly apparent in cell bodies of astrocytes in cortical layer II. Immunolabeling of the EAAT1 was densest in cortical layer II in control cases and induced in deeper layers in alcoholic cases. CONCLUSION Midkine promotes neuronal outgrowth and survival. The up-regulation of MDK protein expression may indicate the induction of reparative processes. The amino acid transporter is vital for the removal of glutamate from the synaptic cleft. At alcohol withdrawal, extracellular glutamate is thought to reach excitotoxic concentrations. Up-regulation of EAAT1 throughout the cortical layers may indicate an attempt to combat elevated glutamate concentrations. The predominant expression of the two proteins in layer II of the cortex implies a region-specific role of astrocytes.
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Affiliation(s)
- Traute Flatscher-Bader
- Alcohol Research Unit, School of Molecular and Microbial Sciences, University of Queensland, St. Lucia, Queensland, Australia.
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28
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Sims NR, Anderson MF. Isolation of mitochondria from rat brain using Percoll density gradient centrifugation. Nat Protoc 2008; 3:1228-39. [DOI: 10.1038/nprot.2008.105] [Citation(s) in RCA: 181] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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Ariyannur PS, Madhavarao CN, Namboodiri AMA. N-acetylaspartate synthesis in the brain: mitochondria vs. microsomes. Brain Res 2008; 1227:34-41. [PMID: 18621030 DOI: 10.1016/j.brainres.2008.06.040] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 06/09/2008] [Accepted: 06/14/2008] [Indexed: 10/21/2022]
Abstract
Several reports during the last three decades have indicated that biosynthesis of N-acetylaspartate (NAA) occurs primarily in the mitochondria. But a recent report by Lu et al. in this journal [2004; 122: 71-78] and subsequent two reports that cited those data suggested a predominant microsomal localization of the NAA biosynthetic enzyme, which is surprising in view of what is known about the biological functions of NAA. Therefore we reinvestigated this issue in rat brain homogenates using a similar fractionation procedure used by Lu et al. but without the loss of enzyme activity that they have encountered. We found that about 70% of the total Asp-NAT activity in the crude supernatant was present in the mitochondrial fraction which is about 5 times more than that in the microsomes. We found similar results in the case of the enzyme from bovine brain. In subsequent studies, we also have found that Asp-NAT activity in the bovine brain is very similar to that in the rat brain in substrate specificity and chromatographic characteristics including the high molecular weight pattern (approx. 670 kD) on size-exclusion HPLC.
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Affiliation(s)
- Prasanth S Ariyannur
- Rm. C 2069, Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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Caspersen CS, Sosunov A, Utkina-Sosunova I, Ratner VI, Starkov AA, Ten VS. An isolation method for assessment of brain mitochondria function in neonatal mice with hypoxic-ischemic brain injury. Dev Neurosci 2008; 30:319-24. [PMID: 18349523 DOI: 10.1159/000121416] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 11/28/2007] [Indexed: 11/19/2022] Open
Abstract
This work was undertaken to develop a method for the isolation of mitochondria from a single cerebral hemisphere in neonatal mice. Mitochondria from the normal mouse brain hemisphere isolated by the proposed method exhibited a good respiratory control ratio of 6.39 +/- 0.53 during glutamate-malate-induced phosphorylating respiration. Electron microscopy showed intact mitochondria. The applicability of this method was tested on mitochondria isolated from naïve mice and their littermates subjected to hypoxic-ischemic insult. Hypoxic-ischemic insult prior to reperfusion resulted in a significant (p < 0.01) inhibition of phosphorylating respiration compared to naïve littermates. This was associated with a profound depletion of the ATP content in the ischemic hemisphere. The expression for Mn superoxide dismutase and cytochrome C (markers for the integrity of the mitochondrial matrix and outer membrane) was determined by Western blot to control for mitochondrial integrity and quantity in the compared samples. Thus, we have developed a method for the isolation of the cerebral mitochondria from a single hemisphere adapted to neonatal mice. This method may serve as a valuable tool to study mitochondrial function in a mouse model of immature brain injury. In addition, the suggested method enables us to examine the mitochondrial functional phenotype in immature mice with a targeted genetic alteration.
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Castello PR, Drechsel DA, Day BJ, Patel M. Inhibition of mitochondrial hydrogen peroxide production by lipophilic metalloporphyrins. J Pharmacol Exp Ther 2007; 324:970-6. [PMID: 18063723 DOI: 10.1124/jpet.107.132134] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Many studies have established a role for oxidative stress and mitochondrial dysfunction as an important mechanism in the pathogenesis of neuronal disorders. Metalloporphyrins are a class of catalytic antioxidants that are capable of detoxifying a wide range of reactive oxygen species. The AEOL112 series of glyoxylate metalloporphyrins were designed with increased lipid solubility for better oral bioavailability and penetration of the blood-brain barrier. The goal of this study was to develop an in vitro assay using rat brain mitochondria to reliably detect endogenously released hydrogen peroxide (H(2)O(2)) and identify glyoxylate metalloporphyrins based on rank order of potency for removal of physiologically relevant H(2)O(2). A polarographic method was established for the sensitive, accurate, and reproducible detection of low levels of H(2)O(2). The assay identified several potent glyoxylate metalloporphyrins with H(2)O(2) scavenging potencies (IC(50)) in the nanomolar range. These results provide a simplified in vitro model system to detect physiologically generated mitochondrial H(2)O(2) as a screening tool to predict the biological efficacy of potential therapeutic entities.
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Affiliation(s)
- Pablo R Castello
- Department of Pharmaceutical Sciences, 4200 East Ninth Ave., School of Pharmacy, C238, Denver, CO 80262, USA
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32
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Paterson AWJ, Curtis JC, Macleod NK. Complex I specific increase in superoxide formation and respiration rate by PrP-null mouse brain mitochondria. J Neurochem 2007; 105:177-91. [PMID: 17999717 DOI: 10.1111/j.1471-4159.2007.05123.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An imbalance in free radical production and removal is considered by many to be an important factor in the etiology of many degenerative diseases. Since mitochondria are a major source of free radicals, we have examined mitochondrial free radical production in relation to oxidative phosphorylation in PrP-null mice. Quantitative electron paramagnetic resonance spectroscopy revealed up to a 70% increase in superoxide production from Complex I of submitochondrial particles prepared from PrP-null mice. This was accompanied by elevated respiratory capacity through Complex I without any discernible alteration in respiratory efficiency. These differences are associated with changes in superoxide dismutase levels and defects in mitochondrial morphology, confirming previously reported results. Our results demonstrate a clear difference in free radical production and oxygen consumption by mitochondrial Complex I between PrP-null mice and wild-type controls, pointing to Complex I as a potential target for pathological change, suggesting similarities between prion-related and other neurodegenerative diseases.
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Affiliation(s)
- Andrew W J Paterson
- Centre for Integrative Physiology, Hugh Robson Building, George Square, Edinburgh, UK
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33
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Zhou Q, Lam PY, Han D, Cadenas E. c-Jun N-terminal kinase regulates mitochondrial bioenergetics by modulating pyruvate dehydrogenase activity in primary cortical neurons. J Neurochem 2007; 104:325-35. [PMID: 17949412 DOI: 10.1111/j.1471-4159.2007.04957.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study examines the role of c-jun N-terminal kinase (JNK) in mitochondrial signaling and bioenergetics in primary cortical neurons and isolated rat brain mitochondria. Exposure of neurons to either anisomycin (an activator of JNK/p38 mitogen-activated protein kinases) or H2O2 resulted in activation (phosphorylation) of JNK (mostly p46(JNK1)) and its translocation to mitochondria. Experiments with mitochondria isolated from either rat brain or primary cortical neurons and incubated with proteinase K revealed that phosphorylated JNK was associated with the outer mitochondrial membrane; this association resulted in the phosphorylation of the E(1alpha) subunit of pyruvate dehydrogenase, a key enzyme that catalyzes the oxidative decarboxylation of pyruvate and that links two major metabolic pathways: glycolysis and the tricarboxylic acid cycle. JNK-mediated phosphorylation of pyruvate dehydrogenase was not observed in experiments carried out with mitoplasts, thus suggesting the requirement of intact, functional mitochondria for this effect. JNK-mediated phosphorylation of pyruvate dehydrogenase was associated with a decline in its activity and, consequently, a shift to anaerobic pyruvate metabolism: the latter was confirmed by increased accumulation of lactic acid and decreased overall energy production (ATP levels). Pyruvate dehydrogenase appears to be a specific phosphorylation target for JNK, for other kinases, such as protein kinase A and protein kinase C did not elicit pyruvate dehydrogenase phosphorylation and did not decrease the activity of the complex. These results suggest that JNK mediates a signaling pathway that regulates metabolic functions in mitochondria as part of a network that coordinates cytosolic and mitochondrial processes relevant for cell function.
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Affiliation(s)
- Qiongqiong Zhou
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90089-9121, USA
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34
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Pandya JD, Pauly JR, Nukala VN, Sebastian AH, Day KM, Korde AS, Maragos WF, Hall ED, Sullivan PG. Post-Injury Administration of Mitochondrial Uncouplers Increases Tissue Sparing and Improves Behavioral Outcome following Traumatic Brain Injury in Rodents. J Neurotrauma 2007; 24:798-811. [PMID: 17518535 DOI: 10.1089/neu.2006.3673] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Following experimental traumatic brain injury (TBI), a rapid and significant necrosis occurs at the site of injury which coincides with significant mitochondrial dysfunction. The present study is driven by the hypothesis that TBI-induced glutamate release increases mitochondrial Ca(2+)cycling/overload, ultimately leading to mitochondrial dysfunction. Based on this premise, mitochondrial uncoupling during the acute phases of TBI-induced excitotoxicity should reduce mitochondrial Ca(2+) uptake (cycling) and reactive oxygen species (ROS) production since both are mitochondrial membrane potential dependent. In the present study, we utilized a cortical impact model of TBI to assess the potential use of mitochondrial uncouplers (2,4-DNP, FCCP) as a neuroprotective therapy. Young adult male rats were intraperitoneally administered vehicle (DMSO), 2,4-DNP (5 mg/kg), or FCCP (2.5 mg/kg) at 5 min post-injury. All animals treated with the uncouplers demonstrated a significant reduction in the amount of cortical damage and behavioral improvement following TBI. In addition, mitochondria isolated from the injured cortex at 3 or 6 h post-injury demonstrated that treatment with the uncouplers significantly improved several parameters of mitochondrial bioenergetics. These results demonstrate that post-injury treatment with mitochondrial uncouplers significantly (p < 0.01) increases cortical tissue sparing ( approximately 12%) and significantly (p< 0.01) improves behavioral outcome following TBI. The mechanism of neuroprotection most likely involves the maintenance of mitochondrial homeostasis by reducing mitochondrial Ca(2+) loading and subsequent mitochondrial dysfunction. These results further implicate mitochondrial dysfunction as an early event in the pathophysiology of TBI and that targeting acute mitochondrial events can result in long-term neuroprotection and improve behavioral outcome following brain injury.
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Affiliation(s)
- Jignesh D Pandya
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536-0305, USA
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35
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Castello PR, Drechsel DA, Patel M. Mitochondria are a major source of paraquat-induced reactive oxygen species production in the brain. J Biol Chem 2007; 282:14186-93. [PMID: 17389593 PMCID: PMC3088512 DOI: 10.1074/jbc.m700827200] [Citation(s) in RCA: 339] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Paraquat (PQ(2+)) is a prototypic toxin known to exert injurious effects through oxidative stress and bears a structural similarity to the Parkinson disease toxicant, 1-methyl-4-pheynlpyridinium. The cellular sources of PQ(2+)-induced reactive oxygen species (ROS) production, specifically in neuronal tissue, remain to be identified. The goal of this study was to determine the involvement of brain mitochondria in PQ(2+)-induced ROS production. Highly purified rat brain mitochondria were obtained using a Percoll density gradient method. PQ(2+)-induced hydrogen peroxide (H(2)O(2)) production was measured by fluorometric and polarographic methods. The production of H(2)O(2) was evaluated in the presence of inhibitors and modulators of the mitochondrial respiratory chain. The results presented here suggest that in the rat brain, (a) mitochondria are a principal cellular site of PQ(2+)-induced H(2)O(2) production, (b) PQ(2+)-induced H(2)O(2) production requires the presence of respiratory substrates, (c) complex III of the electron transport chain is centrally involved in H(2)O(2) production by PQ(2+), and (d) the mechanism by which PQ(2+) generates H(2)O(2) depends on the mitochondrial inner transmembrane potential. These observations were further confirmed by measuring PQ(2+)-induced H(2)O(2) production in primary neuronal cells derived from the midbrain. These findings shed light on the mechanism through which mitochondria may contribute to ROS production by other environmental and endogenous redox cycling agents implicated in Parkinson's disease.
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Affiliation(s)
- Pablo R. Castello
- Department of Pharmaceutical Sciences, University of Colorado at Denver and Health Sciences Center, Denver, Colorado 80262
| | - Derek A. Drechsel
- Department of Pharmaceutical Sciences, University of Colorado at Denver and Health Sciences Center, Denver, Colorado 80262
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado at Denver and Health Sciences Center, Denver, Colorado 80262
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36
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Pallotti F, Lenaz G. Isolation and Subfractionation of Mitochondria from Animal Cells and Tissue Culture Lines. Methods Cell Biol 2007; 80:3-44. [PMID: 17445687 DOI: 10.1016/s0091-679x(06)80001-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Francesco Pallotti
- Dipartimento di Scienze Biomediche Sperimentali e Cliniche, Università degli Studi dell'Insubria, 21100 Varese, Italy
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37
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Rockabrand E, Slepko N, Pantalone A, Nukala VN, Kazantsev A, Marsh JL, Sullivan PG, Steffan JS, Sensi SL, Thompson LM. The first 17 amino acids of Huntingtin modulate its sub-cellular localization, aggregation and effects on calcium homeostasis. Hum Mol Genet 2006; 16:61-77. [PMID: 17135277 DOI: 10.1093/hmg/ddl440] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A truncated form of the Huntington's disease (HD) protein that contains the polyglutamine repeat, Httex1p, causes HD-like phenotypes in multiple model organisms. Molecular signatures of pathogenesis appear to involve distinct domains within this polypeptide. We studied the contribution of each domain, singly or in combination, to sub-cellular localization, aggregation and intracellular Ca2+ ([Ca2+]i) dynamics in cells. We demonstrate that sub-cellular localization is most strongly influenced by the first 17 amino acids, with this sequence critically controlling Httex1p mitochondrial localization and also promoting association with the endoplasmic reticulum (ER) and Golgi. This domain also enhances the formation of visible aggregates and together with the expanded polyQ repeat acutely disrupts [Ca2+]i levels in glutamate-challenged PC12 cells. Isolated cortical mitochondria incubated with Httex1p resulted in uncoupling and depolarization of these organelles, further supporting the idea that Httex1p-dependent mitochondrial dysfunction could be instrumental in promoting acute Ca2+ dyshomeostasis. Interestingly, neither mitochondrial nor ER associations seem to be required to promote long-term [Ca2+]i dyshomeostasis.
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Affiliation(s)
- Erica Rockabrand
- Department of Psychiatry and Human Behavior, University of California, Gillespie 2121, Irvine, CA 92697, USA
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38
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Kriaucionis S, Paterson A, Curtis J, Guy J, Macleod N, Bird A. Gene expression analysis exposes mitochondrial abnormalities in a mouse model of Rett syndrome. Mol Cell Biol 2006; 26:5033-42. [PMID: 16782889 PMCID: PMC1489175 DOI: 10.1128/mcb.01665-05] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Revised: 10/07/2005] [Accepted: 04/05/2006] [Indexed: 11/20/2022] Open
Abstract
Rett syndrome (RTT) is a severe neurological disorder caused by mutations in the X-linked MECP2 gene, which encodes a methyl-CpG binding transcriptional repressor. Using the Mecp2-null mouse (an animal model for RTT) and differential display, we found that mice with neurological symptoms overexpress the nuclear gene for ubiquinol-cytochrome c reductase core protein 1 (Uqcrc1). Chromatin immunoprecipitation demonstrated that MeCP2 interacts with the Uqcrc1 promoter. Uqcrc1 encodes a subunit of mitochondrial respiratory complex III, and isolated mitochondria from the Mecp2-null brain showed elevated respiration rates associated with respiratory complex III and an overall reduction in coupling. A causal link between Uqcrc1 gene overexpression and enhanced complex III activity was established in neuroblastoma cells. Our findings raise the possibility that mitochondrial dysfunction contributes to pathology of the Mecp2-null mouse and may contribute to the long-known resemblance between Rett syndrome and certain mitochondrial disorders.
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Affiliation(s)
- Skirmantas Kriaucionis
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, The King's Buildings, Edinburgh EH9 3JR, United Kingdom
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39
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Shikhanov NP, Ivanov NM, Khovryakov AV, Kaspersen K, McCann GM, Kruglyakov PP, Sosunov AA. Studies of damage to hippocampal neurons in inbred mouse lines in models of epilepsy using kainic acid and pilocarpine. ACTA ACUST UNITED AC 2006; 35:623-8. [PMID: 16342619 DOI: 10.1007/s11055-005-0102-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Identification of the mechanisms of damage to neurons is an important task in contemporary neuroscience and is of enormous importance in medicine. This report compares two models of neuron damage due to hyperexcitation induced by kainic acid and pilocarpine, using two lines of mice, C57BL/6J and FVB/NJ. Neuron damage was more marked in FVB mice, though lethality was greater in C57BL mice. The levels of convulsive activity were not significantly different. Kainic acid had greater tropism for the hippocampus than pilocarpine. Hsp-70 and Egr-1 expression was not significantly different in C57BL and FVB mice. Analysis of the isolated mitochondrial fraction showed that free radical production was different in these mouse lines; this may be one of the reasons for the differential resistance of neurons to hyperexcitation.
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Affiliation(s)
- N P Shikhanov
- Department of Cytology, Mordova State University, Saransk
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40
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Crouch PJ, Blake R, Duce JA, Ciccotosto GD, Li QX, Barnham KJ, Curtain CC, Cherny RA, Cappai R, Dyrks T, Masters CL, Trounce IA. Copper-dependent inhibition of human cytochrome c oxidase by a dimeric conformer of amyloid-beta1-42. J Neurosci 2005; 25:672-9. [PMID: 15659604 PMCID: PMC6725334 DOI: 10.1523/jneurosci.4276-04.2005] [Citation(s) in RCA: 271] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In studies of Alzheimer's disease pathogenesis there is an increasing focus on mechanisms of intracellular amyloid-beta (Abeta) generation and toxicity. Here we investigated the inhibitory potential of the 42 amino acid Abeta peptide (Abeta1-42) on activity of electron transport chain enzyme complexes in human mitochondria. We found that synthetic Abeta1-42 specifically inhibited the terminal complex cytochrome c oxidase (COX) in a dose-dependent manner that was dependent on the presence of Cu2+ and specific "aging" of the Abeta1-42 solution. Maximal COX inhibition occurred when using Abeta1-42 solutions aged for 3-6 h at 30 degrees C. The level of Abeta1-42-mediated COX inhibition increased with aging time up to approximately 6 h and then declined progressively with continued aging to 48 h. Photo-induced cross-linking of unmodified proteins followed by SDS-PAGE analysis revealed dimeric Abeta as the only Abeta species to provide significant temporal correlation with the observed COX inhibition. Analysis of brain and liver from an Alzheimer's model mouse (Tg2576) revealed abundant Abeta immunoreactivity within the brain mitochondria fraction. Our data indicate that endogenous Abeta is associated with brain mitochondria and that Abeta1-42, possibly in its dimeric conformation, is a potent inhibitor of COX, but only when in the presence of Cu2+. We conclude that Cu2+-dependent Abeta-mediated inhibition of COX may be an important contributor to the neurodegeneration process in Alzheimer's disease.
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Affiliation(s)
- Peter J Crouch
- Centre for Neuroscience, The University of Melbourne, Victoria 3010, Australia
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41
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Abstract
BACKGROUND Reactive oxygen species (ROS) are mainly produced in mitochondria and are important contributors to many forms of cell death. ROS also function as second messengers within the cell and may constitute a signaling pathway from mitochondria to the cytoplasm and nucleus. The aim of the present study was to develop a protocol to detect changes in intra- and extramitochondrial releases of ROS, which could be used to analyze the role of mitochondria in cell signaling and cell death. METHODS Fluorescence-based assays were used to measure (a) total production of ROS, (b) intramitochondrial ROS, (c) extramitochondrial hydrogen peroxide, and (d) superoxide outside inverted (inside-out) submitochondrial particles. ROS generation in the samples was increased or decreased by the addition of different substrates, enzymes, and inhibitors of the electron transport chain. RESULTS The individual assays used were sensitive to increased (e.g., after addition of antimycin A; increased signal) and decreased (ROS scavenging; decreased signal) levels of ROS. In combination, the assays provided information about mitochondrial ROS generation and release dynamics from small samples of isolated mitochondria. CONCLUSIONS The combination of fluorescent techniques described is a useful tool to study the role of ROS in cell death and in cellular redox signaling.
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Affiliation(s)
- Gustav Mattiasson
- Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, Lund University, Lund, Sweden.
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42
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Ashton JC, Khalessi A, Kapoor M, Clarkson A, Sammut IA, Darlington CL, Smith PF. Characterization of mitochondrial respiratory chain energetics in the vestibular nucleus complex. Acta Otolaryngol 2005; 125:422-5. [PMID: 15823815 DOI: 10.1080/00016480410024659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
CONCLUSIONS Despite having very high neuronal firing rates, the VNC does not have unusually high mitochondrial activity in vitro. This study is the first in which functionally active mitochondria from the hindbrain have been isolated and characterized. OBJECTIVE Neurons in the vestibular nucleus complex (VNC) have exceptionally high spontaneous firing rates. Neuronal mitochondria generate adenosine triphosphate critical for maintaining the membrane potentials required for axon firing. We therefore hypothesized a high rate of mitochondrial activity in the VNC. MATERIAL AND METHODS To test this hypothesis, we compared mitochondrial activity in the VNC with mitochondrial activity from another area of the hindbrain, the cerebellum. Mitochondrial respiratory activity was assessed by measuring oxidative phosphorylation and mitochondrial respiratory enzyme complex activity. RESULTS Assay results were not significantly different in the VNC compared to those obtained with the cerebellum or with rat brain mitochondria in previous studies.
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Affiliation(s)
- John C Ashton
- Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago Medical School, University of Otago, Dunedin, New Zealand.
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43
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Cho S, Park EM, Zhou P, Frys K, Ross ME, Iadecola C. Obligatory role of inducible nitric oxide synthase in ischemic preconditioning. J Cereb Blood Flow Metab 2005; 25:493-501. [PMID: 15689953 DOI: 10.1038/sj.jcbfm.9600058] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Sublethal insults can induce a transient tolerance toward subsequent lethal ischemia, a phenomenon termed ischemic preconditioning (IPC). In the myocardium, nitric oxide derived from 'inducible' nitric oxide synthase (iNOS or NOS II) plays a critical role in the expression of IPC produced by sublethal ischemia. Here, we investigated whether iNOS is involved in IPC in brain. Ischemic preconditioning was produced in mice by three episodes of 1-min bilateral common carotid artery (BCCA) occlusion, each followed by 5 mins of reperfusion. After 24 h, mice underwent middle cerebral artery (MCA) occlusion for 20 mins. Intraischemic cerebral blood flow was monitored during both in BCCA and MCA occlusion (MCAO) by laser-Doppler flowmetry. Mice were killed 3 days after MCAO, and infarct volume was determined in thionine-stained sections. Infarct volume was significantly reduced 24 h after IPC (70%; P<0.05). Treatment with the iNOS inhibitor aminoguanidine (400 mg/kg), abolished the IPC-induced protection. Furthermore, IPC failed to induce ischemic tolerance in iNOS-null mice. In wild-type mice, IPC increased the resistance to Ca(2+)-mediated depolarization in isolated brain mitochondria. However, in iNOS-null mice IPC failed to induce such resistance. We conclude that iNOS is required for the full expression of IPC and that such effect is coupled to an increased resistance of mitochondria to injury. Thus, iNOS-derived nitric oxide, in addition to its deleterious effects on the late stages of ischemic brain damage, can also be beneficial by promoting ischemic tolerance through signaling, ultimately resulting in mitochondrial protection.
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Affiliation(s)
- Sunghee Cho
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York 10021, USA
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44
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Abstract
Primary neuronal cells used to model physiology are generally limited to embryonic tissue. However, embryonic tissue is not optimal as a model for age-related changes in physiology or late-onset disease. Successful culturing of neurons from adult animals, however, has been historically difficult, if not impossible. Here, we report methodology for routine and reliable cultivation of healthy striatal neurons from adult mice. The new methodology is cost-effective and improves the speed and simplicity of neuronal isolation.
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Affiliation(s)
- Lars Eide
- Mayo Clinic Rochester, Rochester, MN 55905, USA
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45
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Patel M, Li QY, Chang LY, Crapo J, Liang LP. Activation of NADPH oxidase and extracellular superoxide production in seizure-induced hippocampal damage. J Neurochem 2005; 92:123-31. [PMID: 15606902 DOI: 10.1111/j.1471-4159.2004.02838.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We sought to determine whether the extracellular compartment contributed to seizure-induced superoxide (O2*-) production and to determine the role of the NADPH oxidase complex as a source of this O2*- production. The translocation of NADPH oxidase subunits (p47phox, p67phox and rac1) was assessed by immunoblot analysis and NADPH-driven O2*- production was measured using 2-(4-hydroxybenzyl)-6-(4-hydroxyphenyl)-8-benzyl-3,7-dihydroimidazo [1,2-alpha] pyrazin-3-one-enhanced chemiluminescence. Kainate-induced status epilepticus resulted in a time-dependent translocation of NADPH oxidase subunits (p47phox, p67phox and rac-1) from hippocampal cytosol to membrane fractions. Hippocampal membrane fractions from kainate-injected rats showed increased NADPH-driven and diphenylene iodonium-sensitive O2*- production in comparison to vehicle-treated rats. The time-course of kainate-induced NADPH oxidase activation coincided with microglial activation in the rat hippocampus. Finally, kainate-induced neuronal damage and membrane oxygen consumption were inhibited in mice overexpressing extracellular superoxide dismutase. These results suggest that seizure activity activates the membrane NADPH oxidase complex resulting in increased formation of O2*-.
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Affiliation(s)
- Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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46
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Yalcin A, Kilinc E, Kocturk S, Resmi H, Sozmen EY. Effect of melatonin cotreatment against kainic acid on coenzyme Q10, lipid peroxidation and Trx mRNA in rat hippocampus. Int J Neurosci 2004; 114:1085-97. [PMID: 15370175 DOI: 10.1080/00207450490475535] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Oxidative stress is a likely molecular mechanism in the neurotoxicity of kainic acid (KA), an excitotoxic substance. The aim of this report was to assess the effect of melatonin co-treatment against KA by measuring the levels of Coenzyme Q10 (CoQ 10), lipid peroxidation (LPO), and Thioredoxin (Trx) mRNA in the rat hippocampus. The male rats were divided into three groups as saline, KA treatment (15 mg/kg), and KA plus melatonin (20 mg/kg). The levels of LPO and CoQ10 were determined by high pressure liquid chromatography (HPLC) consisting of fluorescence and electro-chemical detectors, respectively. The expression of the Trx gene was quantified using reverse transcription followed by real-time polymerase chain reaction (RT-PCR). The results show that the level of LPO increased although the level of CoQ10 decreased both in homogenates and mitochondria in KA-treated rats However, melatonin co-treatment attenuated the level of LPO and partially restored the level of CoQ10. Melatonin co-treatment against KA did not affect the regulation of Trx. Finally, in the context of the decreased LPO and the increased CoQ10, the results suggest that melatonin may be protective against central nervous system pathologies involving excitotoxicity or where oxidative damage may contribute to mitochondrial dysfunction.
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Affiliation(s)
- Ayfer Yalcin
- Department of Biochemistry, Faculty of Pharmacy, Ege University, Izmir, Turkey.
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47
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Brown MR, Sullivan PG, Dorenbos KA, Modafferi EA, Geddes JW, Steward O. Nitrogen disruption of synaptoneurosomes: an alternative method to isolate brain mitochondria. J Neurosci Methods 2004; 137:299-303. [PMID: 15262074 DOI: 10.1016/j.jneumeth.2004.02.028] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Revised: 02/26/2004] [Accepted: 02/26/2004] [Indexed: 11/17/2022]
Abstract
Mitochondria are known to be localized in synaptic and non-synaptic compartments in the brain. Synaptoneurosomes, which contain high numbers of mitochondria, may act as a major contaminant of currently used isolation techniques. Currently, there is no method employed to successfully disrupt synaptoneurosomes and isolate both synaptic and non-synaptic mitochondria without structural or functional damage. A novel method is reported here for disruption of synaptoneurosomes and isolation of total brain mitochondria from synaptic and non-synaptic sources using a nitrogen decompression technique. Nitrogen gas was dissolved into crude mitochondrial preparations and maintained under constant, moderate pressure. After a short incubation, the pressure was released causing the nitrogen to come out of solution as growing bubbles, which ruptures cellular and synaptoneurosomal membranes. Mitochondria isolated using this rapid technique were bioenergetically competent and exhibited functional characteristics comparable to mitochondria isolated using traditional techniques. This nitrogen decompression technique will allow for further characterization of synaptic pools of mitochondria, which are almost exclusively neuronal in origin.
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Affiliation(s)
- Maile R Brown
- Ph.D. Program in Gerontology, Lexington, KY 40536, USA
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48
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Liang LP, Patel M. Mitochondrial oxidative stress and increased seizure susceptibility in Sod2(-/+) mice. Free Radic Biol Med 2004; 36:542-54. [PMID: 14980699 DOI: 10.1016/j.freeradbiomed.2003.11.029] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2003] [Revised: 11/10/2003] [Accepted: 11/20/2003] [Indexed: 10/26/2022]
Abstract
Epileptic seizures can occur as a result of mitochondrial dysfunction. Mitochondria have vital functions such as energy generation, control of cell death, neurotransmitter synthesis, and free radical production. Which of these critical mitochondrial functions contributes to epileptic seizures is unknown. We demonstrate here that a subset of mice with partial deficiency of the mitochondrial superoxide dismutase (Sod2(-/+)) show increased incidence of spontaneous and handling-induced seizures that correlates with chronic mitochondrial oxidative stress (increased aconitase inactivation and 8-hydroxy-2'-deoxyguanosine formation in mitochondria) and diminished mitochondrial oxygen utilization. Before the age at which spontaneous seizures appear in a subset of the mice, Sod2(-/+) mice demonstrated increased susceptibility to behavioral seizures, mitochondrial aconitase inactivation, and neurodegeneration induced by the administration of kainate. These data suggest that chronic mitochondrial oxidative stress initiated by superoxide (O(2)(.-)) radicals is sufficient to increase seizure susceptibility due to aging, environmental stimulation, or excitotoxin administration. Sod2(-/+) mice showed an age-related decrease in the expression of glial glutamate transporters (GLT-1 and GLAST), suggesting that oxidant-induced inhibition of glutamate transport may play a mechanistic role in rendering some Sod2(-/+) mice susceptible to seizures. In summary, mitochondrial oxidative stress and resultant dysfunction may be an important mechanism underlying certain seizure disorders.
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Affiliation(s)
- Li-Ping Liang
- Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, Denver, CO 80262, USA
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Lu ZH, Chakraborty G, Ledeen RW, Yahya D, Wu G. N-Acetylaspartate synthase is bimodally expressed in microsomes and mitochondria of brain. ACTA ACUST UNITED AC 2004; 122:71-8. [PMID: 14992817 DOI: 10.1016/j.molbrainres.2003.12.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2003] [Indexed: 11/19/2022]
Abstract
N-Acetylaspartate (NAA) is an abundant amino acid derivative of the central nervous system that is localized primarily in neurons and has found widespread use in clinical NMR spectroscopy (MRS) as a non-invasive indicator of neuronal survival and/or viability. Its function, although still obscure, is thought to reflect its unusual metabolic compartmentalization wherein NAA synthase occurs in the neuron and aspartoacylase, the hydrolytic enzyme that removes the acetyl moiety, occurs in myelin and glia. The NAA synthase enzyme, acetyl-CoA/l-aspartate N-acetyltransferase (ANAT), was previously shown to function in mitochondria (MIT), although other subcellular fractions were apparently not examined. In this study we confirmed its presence in MIT but also found significant activity in rat brain microsomes (MIC). The reaction mixture, consisting of [(14)C]aspartate plus acetyl-CoA in Na-phosphate buffer (pH 7), gave rise to [(14)C]NAA that was separated and quantified by TLC. Reaction rates were 29.0+/-0.46 and 6.27+/-0.27 nmol/h/mg for MIC and MIT, respectively. K(m) values and pH optima were similar, and both fractions showed modest enhancement of ANAT activity with the detergents Triton CF-54 and CHAPS. Our tentative conclusion is that ANAT is bimodally targeted to MIT and a component of MIC-likely endoplasmic reticulum. ANAT activity increased in both MIC and MIT between 29 and 60 days of age but differed thereafter in that only MIT ANAT showed a decrease after 1 year.
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Affiliation(s)
- Zi-Hua Lu
- Department of Neurology and Neurosciences, MSB-H506, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
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50
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Lee HM, Hu Z, Ma H, Greeley GH, Wang C, Englander EW. Developmental changes in expression and subcellular localization of the DNA repair glycosylase, MYH, in the rat brain. J Neurochem 2004; 88:394-400. [PMID: 14690527 DOI: 10.1046/j.1471-4159.2003.02164.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mammalian cells employ a network of DNA repair pathways. DNA repair is required during development to ensure accuracy of DNA replication in the rapidly dividing embryonic cells and to maintain genomic integrity in the mature organism. An enzyme involved in repair of replication errors generated on either normal or oxidatively damaged DNA templates, is the mammalian ortholog of the Escherichia coli MutY DNA glycosylase (MYH). We show that levels of MYH isoform, detected at the E14 embryonic stage, decrease during embryonic and neonatal rat development, while new isoforms appear and gradually increase in the neonate and adult brain. The temporally declining expression of embryonic MYH resembles the pattern of proliferating cell nuclear antigen (PCNA) decline during this period. Immunohistochemical analyses of the embryonic brain show that cells staining for MYH initially coincide with cells staining for PCNA. At later stages PCNA declines, while MYH is detected primarily outside the nucleus. MutY-like glycosylase activity for adenines misincorporated opposite oxidized guanines is detected in both, embryonic and adult brain extracts. Together, these findings suggest that in proliferating embryonic cells, MYH might be primarily involved in post replicative repair of nuclear DNA, whereas in post mitotic neurons, in the repair of mitochondrial DNA.
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Affiliation(s)
- Heung-Man Lee
- Department of Surgery, The University of Texas Medical Branch, Galveston, Texas, USA
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