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Jonas EA, Porter GA, Beutner G, Mnatsakanyan N, Alavian KN. Cell death disguised: The mitochondrial permeability transition pore as the c-subunit of the F(1)F(O) ATP synthase. Pharmacol Res 2015; 99:382-92. [PMID: 25956324 PMCID: PMC4567435 DOI: 10.1016/j.phrs.2015.04.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/09/2015] [Accepted: 04/20/2015] [Indexed: 12/16/2022]
Abstract
Ion transport across the mitochondrial inner and outer membranes is central to mitochondrial function, including regulation of oxidative phosphorylation and cell death. Although essential for ATP production by mitochondria, recent findings have confirmed that the c-subunit of the ATP synthase also houses a large conductance uncoupling channel, the mitochondrial permeability transition pore (mPTP), the persistent opening of which produces osmotic dysregulation of the inner mitochondrial membrane and cell death. This review will discuss recent advances in understanding the molecular components of mPTP, its regulatory mechanisms and how these contribute directly to its physiological as well as pathological roles.
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Affiliation(s)
- Elizabeth A Jonas
- Department of Internal Medicine, Section of Endocrinology, Yale University, New Haven, CT, USA.
| | - George A Porter
- Department of Pediatrics (Cardiology), University of Rochester Medical Center, Rochester, NY, USA
| | - Gisela Beutner
- Department of Pediatrics (Cardiology), University of Rochester Medical Center, Rochester, NY, USA
| | - Nelli Mnatsakanyan
- Department of Internal Medicine, Section of Endocrinology, Yale University, New Haven, CT, USA
| | - Kambiz N Alavian
- Division of Brain Sciences, Department of Medicine, Imperial College London, UK
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202
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Abstract
Leigh syndrome (LS) is the most common pediatric presentation of a defined mitochondrial disease. This progressive encephalopathy is characterized pathologically by the development of bilateral symmetrical lesions in the brainstem and basal ganglia that show gliosis, vacuolation, capillary proliferation, relative neuronal preservation, and by hyperlacticacidemia in the blood and/or cerebrospinal fluid. Understanding the molecular mechanisms underlying this unique pathology has been challenging, particularly in view of the heterogeneous and not yet fully determined genetic basis of LS. Moreover, animal models that mimic features of LS have only been created relatively recently. Here, we review the pathology of LS and consider what might be the molecular mechanisms underlying its pathogenesis. Data from a wide range of sources, including patient samples, animal models, and studies of hypoxic-ischemic encephalopathy (a condition that shares features with LS), were used to provide insight into the pathogenic mechanisms that may drive lesion development. Based on current data, we suggest that severe ATP depletion, gliosis, hyperlacticacidemia, reactive oxygen species, and potentially excitotoxicity cumulatively contribute to the neuropathogenesis of LS. An intimate understanding of the molecular mechanisms causing LS is required to accelerate the development of LS treatments.
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203
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Johnson SC, Yanos ME, Bitto A, Castanza A, Gagnidze A, Gonzalez B, Gupta K, Hui J, Jarvie C, Johnson BM, Letexier N, McCanta L, Sangesland M, Tamis O, Uhde L, Van Den Ende A, Rabinovitch PS, Suh Y, Kaeberlein M. Dose-dependent effects of mTOR inhibition on weight and mitochondrial disease in mice. Front Genet 2015; 6:247. [PMID: 26257774 PMCID: PMC4510413 DOI: 10.3389/fgene.2015.00247] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 07/06/2015] [Indexed: 11/13/2022] Open
Abstract
Rapamycin extends lifespan and attenuates age-related pathologies in mice when administered through diet at 14 parts per million (PPM). Recently, we reported that daily intraperitoneal injection of rapamycin at 8 mg/kg attenuates mitochondrial disease symptoms and progression in the Ndufs4 knockout mouse model of Leigh Syndrome. Although rapamycin is a widely used pharmaceutical agent dosage has not been rigorously examined and no dose-response profile has been established. Given these observations we sought to determine if increased doses of oral rapamycin would result in more robust impact on mTOR driven parameters. To test this hypothesis, we compared the effects of dietary rapamycin at doses ranging from 14 to 378 PPM on developmental weight in control and Ndufs4 knockout mice and on health and survival in the Ndufs4 knockout model. High dose rapamycin was well tolerated, dramatically reduced weight gain during development, and overcame gender differences. The highest oral dose, approximately 27-times the dose shown to extend murine lifespan, increased survival in Ndufs4 knockout mice similarly to daily rapamycin injection without observable adverse effects. These findings have broad implications for the effective use of rapamycin in murine studies and for the translational potential of rapamycin in the treatment of mitochondrial disease. This data, further supported by a comparison of available literature, suggests that 14 PPM dietary rapamycin is a sub-optimal dose for targeting mTOR systemically in mice. Our findings suggest that the role of mTOR in mammalian biology may be broadly underestimated when determined through treatment with rapamycin at commonly used doses.
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Affiliation(s)
- Simon C Johnson
- Department of Pathology, University of Washington Seattle, WA, USA ; Department of Genetics, Albert Einstein College of Medicine New York, NY, USA
| | - Melana E Yanos
- Department of Pathology, University of Washington Seattle, WA, USA ; Department of Psychology, University of Washington Seattle, WA, USA
| | - Alessandro Bitto
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Anthony Castanza
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Arni Gagnidze
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Brenda Gonzalez
- Department of Genetics, Albert Einstein College of Medicine New York, NY, USA
| | - Kanav Gupta
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Jessica Hui
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Conner Jarvie
- Department of Pathology, University of Washington Seattle, WA, USA
| | | | - Nicolas Letexier
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Lanny McCanta
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Maya Sangesland
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Oliver Tamis
- Department of Pathology, University of Washington Seattle, WA, USA
| | - Lauren Uhde
- Department of Pathology, University of Washington Seattle, WA, USA
| | | | | | - Yousin Suh
- Department of Genetics, Albert Einstein College of Medicine New York, NY, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington Seattle, WA, USA
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204
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Maneb-induced dopaminergic neuronal death is not affected by loss of mitochondrial complex I activity: results from primary mesencephalic dopaminergic neurons cultured from individual Ndufs4+/+ and Ndufs4-/- mouse embryos. Neuroreport 2015; 25:1350-5. [PMID: 25275677 DOI: 10.1097/wnr.0000000000000271] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Primary cultures from embryonic mouse ventral mesencephalon are widely used for investigating the mechanisms of dopaminergic neuronal death in Parkinson's disease models. Specifically, single mouse or embryo cultures from littermates can be very useful for comparative studies involving transgenic mice when the neuron cultures are to be prepared before genotyping. However, preparing single mouse embryo culture is technically challenging because of the small number of cells present in the mesencephalon of each embryo (150 000-300 000), of which only 0.5-5% are tyrosine hydroxylase-positive, dopaminergic neurons. In this study, we optimized the procedure for preparing primary mesencephalic neuron cultures from individual mouse embryos. Mesencephalic neurons were dissociated delicately, plated on Aclar film coverslips, and incubated in DMEM supplemented with fetal bovine serum for 5 days and then N2 supplement was added for 1 day, which resulted in the best survival of dopaminergic neurons from each embryo. Using this optimized method, we prepared mesencephalic neuron cultures from single Ndufs4 or Ndufs4 embryos and investigated the role of mitochondrial complex I in maneb-induced dopamine neuron death. Our results suggest that maneb toxicity to dopamine neurons is not affected by the loss of mitochondrial complex I activity in Ndufs4 cultures.
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205
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Pathak D, Shields LY, Mendelsohn BA, Haddad D, Lin W, Gerencser AA, Kim H, Brand MD, Edwards RH, Nakamura K. The role of mitochondrially derived ATP in synaptic vesicle recycling. J Biol Chem 2015; 290:22325-36. [PMID: 26126824 DOI: 10.1074/jbc.m115.656405] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Indexed: 01/03/2023] Open
Abstract
Synaptic mitochondria are thought to be critical in supporting neuronal energy requirements at the synapse, and bioenergetic failure at the synapse may impair neural transmission and contribute to neurodegeneration. However, little is known about the energy requirements of synaptic vesicle release or whether these energy requirements go unmet in disease, primarily due to a lack of appropriate tools and sensitive assays. To determine the dependence of synaptic vesicle cycling on mitochondrially derived ATP levels, we developed two complementary assays sensitive to mitochondrially derived ATP in individual, living hippocampal boutons. The first is a functional assay for mitochondrially derived ATP that uses the extent of synaptic vesicle cycling as a surrogate for ATP level. The second uses ATP FRET sensors to directly measure ATP at the synapse. Using these assays, we show that endocytosis has high ATP requirements and that vesicle reacidification and exocytosis require comparatively little energy. We then show that to meet these energy needs, mitochondrially derived ATP is rapidly dispersed in axons, thereby maintaining near normal levels of ATP even in boutons lacking mitochondria. As a result, the capacity for synaptic vesicle cycling is similar in boutons without mitochondria as in those with mitochondria. Finally, we show that loss of a key respiratory subunit implicated in Leigh disease markedly decreases mitochondrially derived ATP levels in axons, thus inhibiting synaptic vesicle cycling. This proves that mitochondria-based energy failure can occur and be detected in individual neurons that have a genetic mitochondrial defect.
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Affiliation(s)
- Divya Pathak
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158
| | - Lauren Y Shields
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158, the Department of Neurology and Graduate Programs in Neuroscience and Biomedical Sciences, University of California at San Francisco, San Francisco, California 94158
| | - Bryce A Mendelsohn
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158, the Department of Pediatrics, University of California at San Francisco, San Francisco, California 94143, and
| | - Dominik Haddad
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158
| | - Wei Lin
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158
| | - Akos A Gerencser
- the Buck Institute for Research on Aging, Novato, California 94945
| | - Hwajin Kim
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158
| | - Martin D Brand
- the Buck Institute for Research on Aging, Novato, California 94945
| | - Robert H Edwards
- the Department of Neurology and Graduate Programs in Neuroscience and Biomedical Sciences, University of California at San Francisco, San Francisco, California 94158
| | - Ken Nakamura
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158, the Department of Neurology and Graduate Programs in Neuroscience and Biomedical Sciences, University of California at San Francisco, San Francisco, California 94158,
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206
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Opa1 overexpression ameliorates the phenotype of two mitochondrial disease mouse models. Cell Metab 2015; 21:845-54. [PMID: 26039449 PMCID: PMC4457891 DOI: 10.1016/j.cmet.2015.04.016] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 02/13/2015] [Accepted: 04/12/2015] [Indexed: 02/07/2023]
Abstract
Increased levels of the mitochondria-shaping protein Opa1 improve respiratory chain efficiency and protect from tissue damage, suggesting that it could be an attractive target to counteract mitochondrial dysfunction. Here we show that Opa1 overexpression ameliorates two mouse models of defective mitochondrial bioenergetics. The offspring from crosses of a constitutive knockout for the structural complex I component Ndufs4 (Ndufs4(-/-)), and of a muscle-specific conditional knockout for the complex IV assembly factor Cox15 (Cox15(sm/sm)), with Opa1 transgenic (Opa1(tg)) mice showed improved motor skills and respiratory chain activities compared to the naive, non-Opa1-overexpressing, models. While the amelioration was modest in Ndufs4(-/-)::Opa1(tg) mice, correction of cristae ultrastructure and mitochondrial respiration, improvement of motor performance and prolongation of lifespan were remarkable in Cox15(sm/sm)::Opa1(tg) mice. Mechanistically, respiratory chain supercomplexes were increased in Cox15(sm/sm)::Opa1(tg) mice, and residual monomeric complex IV was stabilized. In conclusion, cristae shape amelioration by controlled Opa1 overexpression improves two mouse models of mitochondrial disease.
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207
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Abstract
Proinflammatory macrophage activation is coupled to a metabolic switch toward glycolysis. In Cell Metabolism, Jin et al. (2014) show that this process is negatively regulated by mitochondrial electron transport chain complex I through both cell intrinsic and extrinsic pathways.
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Affiliation(s)
- Stanley Ching-Cheng Huang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO63110-1093, USA
| | - Edward J Pearce
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO63110-1093, USA.
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208
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Kim HW, Choi WS, Sorscher N, Park HJ, Tronche F, Palmiter RD, Xia Z. Genetic reduction of mitochondrial complex I function does not lead to loss of dopamine neurons in vivo. Neurobiol Aging 2015; 36:2617-27. [PMID: 26070241 DOI: 10.1016/j.neurobiolaging.2015.05.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 12/21/2022]
Abstract
Inhibition of mitochondrial complex I activity is hypothesized to be one of the major mechanisms responsible for dopaminergic neuron death in Parkinson's disease. However, loss of complex I activity by systemic deletion of the Ndufs4 gene, one of the subunits comprising complex I, does not cause dopaminergic neuron death in culture. Here, we generated mice with conditional Ndufs4 knockout in dopaminergic neurons (Ndufs4 conditional knockout mice [cKO]) to examine the effect of complex I inhibition on dopaminergic neuron function and survival during aging and on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in vivo. Ndufs4 cKO mice did not show enhanced dopaminergic neuron loss in the substantia nigra pars compacta or dopamine-dependent motor deficits over the 24-month life span. These mice were just as susceptible to MPTP as control mice. However, compared with control mice, Ndufs4 cKO mice exhibited an age-dependent reduction of dopamine in the striatum and increased α-synuclein phosphorylation in dopaminergic neurons of the substantia nigra pars compacta. We also used an inducible Ndufs4 knockout mouse strain (Ndufs4 inducible knockout) in which Ndufs4 is conditionally deleted in all cells in adult to examine the effect of adult onset, complex I inhibition on MPTP sensitivity of dopaminergic neurons. The Ndufs4 inducible knockout mice exhibited similar sensitivity to MPTP as control littermates. These data suggest that mitochondrial complex I inhibition in dopaminergic neurons does contribute to dopamine loss and the development of α-synuclein pathology. However, it is not sufficient to cause cell-autonomous dopaminergic neuron death during the normal life span of mice. Furthermore, mitochondrial complex I inhibition does not underlie MPTP toxicity in vivo in either cell autonomous or nonautonomous manner. These results provide strong evidence that inhibition of mitochondrial complex I activity is not sufficient to cause dopaminergic neuron death during aging nor does it contribute to dopamine neuron toxicity in the MPTP model of Parkinson's disease. These findings suggest the existence of alternative mechanisms of dopaminergic neuron death independent of mitochondrial complex I inhibition.
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Affiliation(s)
- Hyung-Wook Kim
- Toxicology Program in the Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; College of Life Sciences, Sejong University, Seoul, Korea
| | - Won-Seok Choi
- Toxicology Program in the Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; School of Biological Sciences and Technology, College of Natural Sciences, Chonnam National University, Gwangju, Korea; College of Medicine, Chonnam National University, Gwangju, Korea
| | - Noah Sorscher
- Graduate Program in Neurobiology & Behavior, University of Washington, Seattle, WA, USA
| | - Hyung Joon Park
- School of Biological Sciences and Technology, College of Natural Sciences, Chonnam National University, Gwangju, Korea; College of Medicine, Chonnam National University, Gwangju, Korea
| | - François Tronche
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_CR18, Neuroscience Paris-Seine, Paris, France; Centre National de la Recherche Scientifique UMR 8246, Paris, France; Institut National de la Santé et de la Rechesrche Médicale U1130, Paris, France
| | - Richard D Palmiter
- Howard Huges Medical Institute, University of Washington, Seattle, WA, USA; Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Zhengui Xia
- Toxicology Program in the Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Graduate Program in Neurobiology & Behavior, University of Washington, Seattle, WA, USA.
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209
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Nallar SC, Kalvakolanu DV. Interferons, signal transduction pathways, and the central nervous system. J Interferon Cytokine Res 2015; 34:559-76. [PMID: 25084173 DOI: 10.1089/jir.2014.0021] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The interferon (IFN) family of cytokines participates in the development of innate and acquired immune defenses against various pathogens and pathogenic stimuli. Discovered originally as a proteinaceous substance secreted from virus-infected cells that afforded immunity to neighboring cells from virus infection, these cytokines are now implicated in various human pathologies, including control of tumor development, cell differentiation, and autoimmunity. It is now believed that the IFN system (IFN genes and the genes induced by them, and the factors that regulate these processes) is a generalized alarm of cellular stress, including DNA damage. IFNs exert both beneficial and deleterious effects on the central nervous system (CNS). Our knowledge of the IFN-regulated processes in the CNS is far from being clear. In this article, we reviewed the current understanding of IFN signal transduction pathways and gene products that might have potential relevance to diseases of the CNS.
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Affiliation(s)
- Shreeram C Nallar
- Department of Microbiology & Immunology, Program in Oncology, Greenebaum Cancer Center, University of Maryland School of Medicine , Baltimore, Maryland
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210
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Liu L, Zhang K, Sandoval H, Yamamoto S, Jaiswal M, Sanz E, Li Z, Hui J, Graham BH, Quintana A, Bellen HJ. Glial lipid droplets and ROS induced by mitochondrial defects promote neurodegeneration. Cell 2015; 160:177-90. [PMID: 25594180 DOI: 10.1016/j.cell.2014.12.019] [Citation(s) in RCA: 557] [Impact Index Per Article: 61.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 09/22/2014] [Accepted: 11/19/2014] [Indexed: 12/13/2022]
Abstract
Reactive oxygen species (ROS) and mitochondrial defects in neurons are implicated in neurodegenerative disease. Here, we find that a key consequence of ROS and neuronal mitochondrial dysfunction is the accumulation of lipid droplets (LD) in glia. In Drosophila, ROS triggers c-Jun-N-terminal Kinase (JNK) and Sterol Regulatory Element Binding Protein (SREBP) activity in neurons leading to LD accumulation in glia prior to or at the onset of neurodegeneration. The accumulated lipids are peroxidated in the presence of ROS. Reducing LD accumulation in glia and lipid peroxidation via targeted lipase overexpression and/or lowering ROS significantly delays the onset of neurodegeneration. Furthermore, a similar pathway leads to glial LD accumulation in Ndufs4 mutant mice with neuronal mitochondrial defects, suggesting that LD accumulation following mitochondrial dysfunction is an evolutionarily conserved phenomenon, and represents an early, transient indicator and promoter of neurodegenerative disease.
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Affiliation(s)
- Lucy Liu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ke Zhang
- Structural and Computational Biology & Molecular Biophysics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Elisenda Sanz
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Zhihong Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jessica Hui
- Center for Developmental Therapeutics, University of Washington, Seattle, WA, 98195, USA
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Albert Quintana
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Center for Developmental Therapeutics, University of Washington, Seattle, WA, 98195, USA; Department of Pediatrics, University of Washington, Seattle, WA, 98195, USA
| | - Hugo J Bellen
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Structural and Computational Biology & Molecular Biophysics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
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211
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How do changes in the mtDNA and mitochondrial dysfunction influence cancer and cancer therapy? Challenges, opportunities and models. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 764:16-30. [DOI: 10.1016/j.mrrev.2015.01.001] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 01/11/2015] [Accepted: 01/12/2015] [Indexed: 12/28/2022]
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212
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Alam MT, Manjeri GR, Rodenburg RJ, Smeitink JAM, Notebaart RA, Huynen M, Willems PHGM, Koopman WJH. Skeletal muscle mitochondria of NDUFS4-/- mice display normal maximal pyruvate oxidation and ATP production. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:526-33. [PMID: 25687896 DOI: 10.1016/j.bbabio.2015.02.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 02/03/2015] [Accepted: 02/07/2015] [Indexed: 10/24/2022]
Abstract
Mitochondrial ATP production is mediated by the oxidative phosphorylation (OXPHOS) system, which consists of four multi-subunit complexes (CI-CIV) and the FoF1-ATP synthase (CV). Mitochondrial disorders including Leigh Syndrome often involve CI dysfunction, the pathophysiological consequences of which still remain incompletely understood. Here we combined experimental and computational strategies to gain mechanistic insight into the energy metabolism of isolated skeletal muscle mitochondria from 5-week-old wild-type (WT) and CI-deficient NDUFS4-/- (KO) mice. Enzyme activity measurements in KO mitochondria revealed a reduction of 79% in maximal CI activity (Vmax), which was paralleled by 45-72% increase in Vmax of CII, CIII, CIV and citrate synthase. Mathematical modeling of mitochondrial metabolism predicted that these Vmax changes do not affect the maximal rates of pyruvate (PYR) oxidation and ATP production in KO mitochondria. This prediction was empirically confirmed by flux measurements. In silico analysis further predicted that CI deficiency altered the concentration of intermediate metabolites, modestly increased mitochondrial NADH/NAD+ ratio and stimulated the lower half of the TCA cycle, including CII. Several of the predicted changes were previously observed in experimental models of CI-deficiency. Interestingly, model predictions further suggested that CI deficiency only has major metabolic consequences when its activity decreases below 90% of normal levels, compatible with a biochemical threshold effect. Taken together, our results suggest that mouse skeletal muscle mitochondria possess a substantial CI overcapacity, which minimizes the effects of CI dysfunction on mitochondrial metabolism in this otherwise early fatal mouse model.
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Affiliation(s)
- Mohammad T Alam
- Department of Biochemistry, RIMLS, Radboud University Medical Center, Nijmegen, The Netherlands; Centre for Systems Biology and Bioenergetics, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Ganesh R Manjeri
- Department of Biochemistry, RIMLS, Radboud University Medical Center, Nijmegen, The Netherlands; Centre for Systems Biology and Bioenergetics, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Richard J Rodenburg
- Centre for Systems Biology and Bioenergetics, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, NCMD, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Jan A M Smeitink
- Centre for Systems Biology and Bioenergetics, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, NCMD, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Richard A Notebaart
- Centre for Systems Biology and Bioenergetics, Radboud University Medical Centre, Nijmegen, The Netherlands; Centre for Molecular and Biomolecular Informatics, RIMLS, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Martijn Huynen
- Centre for Systems Biology and Bioenergetics, Radboud University Medical Centre, Nijmegen, The Netherlands; Centre for Molecular and Biomolecular Informatics, RIMLS, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Peter H G M Willems
- Department of Biochemistry, RIMLS, Radboud University Medical Center, Nijmegen, The Netherlands; Centre for Systems Biology and Bioenergetics, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Werner J H Koopman
- Department of Biochemistry, RIMLS, Radboud University Medical Center, Nijmegen, The Netherlands; Centre for Systems Biology and Bioenergetics, Radboud University Medical Centre, Nijmegen, The Netherlands.
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213
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Torraco A, Peralta S, Iommarini L, Diaz F. Mitochondrial Diseases Part I: mouse models of OXPHOS deficiencies caused by defects in respiratory complex subunits or assembly factors. Mitochondrion 2015; 21:76-91. [PMID: 25660179 DOI: 10.1016/j.mito.2015.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/22/2014] [Accepted: 01/05/2015] [Indexed: 10/24/2022]
Abstract
Mitochondrial disorders are the most common inborn errors of metabolism affecting the oxidative phosphorylation system (OXPHOS). Because of the poor knowledge of the pathogenic mechanisms, a cure for these disorders is still unavailable and all the treatments currently in use are supportive more than curative. Therefore, in the past decade a great variety of mouse models have been developed to assess the in vivo function of several mitochondrial proteins involved in human diseases. Due to the genetic and physiological similarity to humans, mice represent reliable models to study the pathogenic mechanisms of mitochondrial disorders and are precious to test new therapeutic approaches. Here we summarize the features of several mouse models of mitochondrial diseases directly related to defects in subunits of the OXPHOS complexes or in assembly factors. We discuss how these models recapitulate many human conditions and how they have contributed to the understanding of mitochondrial function in health and disease.
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Affiliation(s)
- Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15-00146 Rome, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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214
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Yu AK, Song L, Murray KD, van der List D, Sun C, Shen Y, Xia Z, Cortopassi GA. Mitochondrial complex I deficiency leads to inflammation and retinal ganglion cell death in the Ndufs4 mouse. Hum Mol Genet 2015; 24:2848-60. [PMID: 25652399 DOI: 10.1093/hmg/ddv045] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 02/02/2015] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial complex I (NADH dehydrogenase) is a major contributor to neuronal energetics, and mutations in complex I lead to vision loss. Functional, neuroanatomical and transcriptional consequences of complex I deficiency were investigated in retinas of the Ndufs4 knockout mouse. Whole-eye ERGs and multielectrode arrays confirmed a major retinal ganglion cell functional loss at P32, and retinal ganglion cell loss at P42. RNAseq demonstrated a mild and then sharp increase in innate immune and inflammatory retinal transcripts at P22 and P33, respectively, which were confirmed with QRT-PCR. Intraperitoneal injection of the inflammogen lipopolysaccharide further reduced retinal ganglion cell function in Ndufs4 KO, supporting the connection between inflammatory activation and functional loss. Complex I deficiency in the retina clearly caused innate immune and inflammatory markers to increase coincident with loss of vision, and RGC functional loss. How complex I incites inflammation and functional loss is not clear, but could be the result of misfolded complex I generating a 'non-self' response, and induction of innate immune response transcripts was observed before functional loss at P22, including β-2 microglobulin and Cx3cr1, and during vision loss at P31 (B2m, Tlr 2, 3, 4, C1qa, Cx3cr1 and Fas). These data support the hypothesis that mitochondrial complex I dysfunction in the retina triggers an innate immune and inflammatory response that results in loss of retinal ganglion cell function and death, as in Leber's hereditary Optic Neuropathy and suggests novel therapeutic routes to counter mitochondrial defects that contribute to vision loss.
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Affiliation(s)
| | | | | | | | - Chao Sun
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA and
| | - Yan Shen
- Veterinary Medicine, Molecular Biosciences
| | - Zhengui Xia
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
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215
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Generating Mouse Models of Mitochondrial Disease. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00043-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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216
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Distelmaier F, Valsecchi F, Liemburg-Apers DC, Lebiedzinska M, Rodenburg RJ, Heil S, Keijer J, Fransen J, Imamura H, Danhauser K, Seibt A, Viollet B, Gellerich FN, Smeitink JAM, Wieckowski MR, Willems PHGM, Koopman WJH. Mitochondrial dysfunction in primary human fibroblasts triggers an adaptive cell survival program that requires AMPK-α. Biochim Biophys Acta Mol Basis Dis 2014; 1852:529-40. [PMID: 25536029 DOI: 10.1016/j.bbadis.2014.12.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 12/11/2014] [Accepted: 12/15/2014] [Indexed: 01/06/2023]
Abstract
Dysfunction of complex I (CI) of the mitochondrial electron transport chain (ETC) features prominently in human pathology. Cell models of ETC dysfunction display adaptive survival responses that still are poorly understood but of relevance for therapy development. Here we comprehensively examined how primary human skin fibroblasts adapt to chronic CI inhibition. CI inhibition triggered transient and sustained changes in metabolism, redox homeostasis and mitochondrial (ultra)structure but no cell senescence/death. CI-inhibited cells consumed no oxygen and displayed minor mitochondrial depolarization, reverse-mode action of complex V, a slower proliferation rate and futile mitochondrial biogenesis. Adaptation was neither prevented by antioxidants nor associated with increased PGC1-α/SIRT1/mTOR levels. Survival of CI-inhibited cells was strictly glucose-dependent and accompanied by increased AMPK-α phosphorylation, which occurred without changes in ATP or cytosolic calcium levels. Conversely, cells devoid of AMPK-α died upon CI inhibition. Chronic CI inhibition did not increase mitochondrial superoxide levels or cellular lipid peroxidation and was paralleled by a specific increase in SOD2/GR, whereas SOD1/CAT/Gpx1/Gpx2/Gpx5 levels remained unchanged. Upon hormone stimulation, fully adapted cells displayed aberrant cytosolic and ER calcium handling due to hampered ATP fueling of ER calcium pumps. It is concluded that CI dysfunction triggers an adaptive program that depends on extracellular glucose and AMPK-α. This response avoids cell death by suppressing energy crisis, oxidative stress induction and substantial mitochondrial depolarization.
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Affiliation(s)
- Felix Distelmaier
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Federica Valsecchi
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Dania C Liemburg-Apers
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | | | - Richard J Rodenburg
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Sandra Heil
- Department of Human and Animal Physiology, Wageningen University, 6708 WD Wageningen, The Netherlands
| | - Jaap Keijer
- Department of Human and Animal Physiology, Wageningen University, 6708 WD Wageningen, The Netherlands
| | - Jack Fransen
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Hiromi Imamura
- The Hakubi Project, Kyoto University, 606-8501 Kyoto, Japan
| | - Katharina Danhauser
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Annette Seibt
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Benoit Viollet
- Institut Cochin, NSERM U1016, Université Paris Descartes, 75014 Paris, France
| | - Frank N Gellerich
- Department of Stereotactic Neurosurgery, Otto-von-Guericke-Universität, 39120 Magdeburg, Germany
| | - Jan A M Smeitink
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | | | - Peter H G M Willems
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Werner J H Koopman
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands.
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217
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Kanabus M, Heales SJ, Rahman S. Development of pharmacological strategies for mitochondrial disorders. Br J Pharmacol 2014; 171:1798-817. [PMID: 24116962 PMCID: PMC3976606 DOI: 10.1111/bph.12456] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 09/21/2013] [Accepted: 09/26/2013] [Indexed: 01/19/2023] Open
Abstract
Mitochondrial diseases are an unusually genetically and phenotypically heterogeneous group of disorders, which are extremely challenging to treat. Currently, apart from supportive therapy, there are no effective treatments for the vast majority of mitochondrial diseases. Huge scientific effort, however, is being put into understanding the mechanisms underlying mitochondrial disease pathology and developing potential treatments. To date, a variety of treatments have been evaluated by randomized clinical trials, but unfortunately, none of these has delivered breakthrough results. Increased understanding of mitochondrial pathways and the development of many animal models, some of which are accurate phenocopies of human diseases, are facilitating the discovery and evaluation of novel prospective treatments. Targeting reactive oxygen species has been a treatment of interest for many years; however, only in recent years has it been possible to direct antioxidant delivery specifically into the mitochondria. Increasing mitochondrial biogenesis, whether by pharmacological approaches, dietary manipulation or exercise therapy, is also currently an active area of research. Modulating mitochondrial dynamics and mitophagy and the mitochondrial membrane lipid milieu have also emerged as possible treatment strategies. Recent technological advances in gene therapy, including allotopic and transkingdom gene expression and mitochondrially targeted transcription activator-like nucleases, have led to promising results in cell and animal models of mitochondrial diseases, but most of these techniques are still far from clinical application.
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Affiliation(s)
- M Kanabus
- Clinical and Molecular Genetics Unit, UCL Institute of Child Health, London, UK
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218
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Neuronal and astrocyte dysfunction diverges from embryonic fibroblasts in the Ndufs4fky/fky mouse. Biosci Rep 2014; 34:e00151. [PMID: 25312000 PMCID: PMC4240023 DOI: 10.1042/bsr20140151] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Mitochondrial dysfunction causes a range of early-onset neurological diseases and contributes to neurodegenerative conditions. The mechanisms of neurological damage however are poorly understood, as accessing relevant tissue from patients is difficult, and appropriate models are limited. Hence, we assessed mitochondrial function in neurologically relevant primary cell lines from a CI (complex I) deficient Ndufs4 KO (knockout) mouse (Ndufs4fky/fky) modelling aspects of the mitochondrial disease LS (Leigh syndrome), as well as MEFs (mouse embryonic fibroblasts). Although CI structure and function were compromised in all Ndufs4fky/fky cell types, the mitochondrial membrane potential was selectively impaired in the MEFs, correlating with decreased CI-dependent ATP synthesis. In addition, increased ROS (reactive oxygen species) generation and altered sensitivity to cell death were only observed in Ndufs4fky/fky primary MEFs. In contrast, Ndufs4fky/fky primary isocortical neurons and primary isocortical astrocytes displayed only impaired ATP generation without mitochondrial membrane potential changes. Therefore the neurological dysfunction in the Ndufs4fky/fky mouse may partly originate from a more severe ATP depletion in neurons and astrocytes, even at the expense of maintaining the mitochondrial membrane potential. This may provide protection from cell death, but would ultimately compromise cell functionality in neurons and astrocytes. Furthermore, RET (reverse electron transfer) from complex II to CI appears more prominent in neurons than MEFs or astrocytes, and is attenuated in Ndufs4fky/fky cells.
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219
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Song L, Cortopassi G. Mitochondrial complex I defects increase ubiquitin in substantia nigra. Brain Res 2014; 1594:82-91. [PMID: 25446449 DOI: 10.1016/j.brainres.2014.11.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 10/16/2014] [Accepted: 11/07/2014] [Indexed: 11/18/2022]
Abstract
Parkinson׳s disease (PD) is the second most common neurodegenerative disorder in the developed world, and is characterized by the loss of dopaminergic (DA) neurons in the substantia nigra (SN) of midbrain. Mitochondrial complex I dysfunction has been implicated in PD pathophysiology, yet the molecular mechanism by which complex I defects may cause DA neurodegeneration remain unclear. Using Ndufs4 mouse model of mitochondrial complex I deficiency, we observed a remarkable ubiquitin protein increase in SN of Ndufs4-/- (KO) mice. By contrast, neurofilaments were significantly decreased in SN of KO mice. Furthermore, mass spectrometry and co-immunoprecipitation (Co-IP) analysis indicated an increase in ubiquitinated neurofilaments in midbrain of KO mice, whereas 20S proteasome activities were decreased, which could potentially explain the buildup of ubiquitin protein. Collectively, these data suggest that mitochondrial complex I defects cause proteasome inhibition, a consequent increase in ubiquitinated neurofilaments and other proteins, and decrease the expression of neurofilaments that could be relevant to the mechanism of DA neuronal death in PD.
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Affiliation(s)
- Lanying Song
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA
| | - Gino Cortopassi
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA.
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220
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Mitochondrial complex I activity suppresses inflammation and enhances bone resorption by shifting macrophage-osteoclast polarization. Cell Metab 2014; 20:483-98. [PMID: 25130399 PMCID: PMC4156549 DOI: 10.1016/j.cmet.2014.07.011] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/27/2014] [Accepted: 07/10/2014] [Indexed: 01/09/2023]
Abstract
Mitochondrial complex I (CI) deficiency is associated with multiple neurological and metabolic disorders. However, its effect on innate immunity and bone remodeling is unclear. Using deletion of the essential CI subunit Ndufs4 as a model for mitochondrial dysfunction, we report that mitochondria suppress macrophage activation and inflammation while promoting osteoclast differentiation and bone resorption via both cell-autonomous and systemic regulation. Global Ndufs4 deletion causes systemic inflammation and osteopetrosis. Hematopoietic Ndufs4 deletion causes an intrinsic lineage shift from osteoclast to macrophage. Liver Ndufs4 deletion causes a metabolic shift from fatty acid oxidation to glycolysis, accumulating fatty acids and lactate (FA/LAC) in the circulation. FA/LAC further activates Ndufs4(-/-) macrophages via reactive oxygen species induction and diminishes osteoclast lineage commitment in Ndufs4(-/-) progenitors; both inflammation and osteopetrosis in Ndufs4(-/-) mice are attenuated by TLR4/2 deletion. Together, these findings reveal mitochondrial CI as a critical rheostat of innate immunity and skeletal homeostasis.
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221
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Pulliam DA, Deepa SS, Liu Y, Hill S, Lin AL, Bhattacharya A, Shi Y, Sloane L, Viscomi C, Zeviani M, Van Remmen H. Complex IV-deficient Surf1(-/-) mice initiate mitochondrial stress responses. Biochem J 2014; 462:359-71. [PMID: 24911525 PMCID: PMC4145821 DOI: 10.1042/bj20140291] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mutations in SURF1 (surfeit locus protein 1) COX (cytochrome c oxidase) assembly protein are associated with Leigh's syndrome, a human mitochondrial disorder that manifests as severe mitochondrial phenotypes and early lethality. In contrast, mice lacking the SURF1 protein (Surf1-/-) are viable and were previously shown to have enhanced longevity and a greater than 50% reduction in COX activity. We measured mitochondrial function in heart and skeletal muscle, and despite the significant reduction in COX activity, we found little or no difference in ROS (reactive oxygen species) generation, membrane potential, ATP production or respiration in isolated mitochondria from Surf1-/- mice compared with wild-type. However, blood lactate levels were elevated and Surf1-/- mice had reduced running endurance, suggesting compromised mitochondrial energy metabolism in vivo. Decreased COX activity in Surf1-/- mice is associated with increased markers of mitochondrial biogenesis [PGC-1α (peroxisome-proliferator-activated receptor γ co-activator 1α) and VDAC (voltage-dependent anion channel)] in both heart and skeletal muscle. Although mitochondrial biogenesis is a common response in the two tissues, skeletal muscle has an up-regulation of the UPRMT (mitochondrial unfolded protein response) and heart exhibits induction of the Nrf2 (nuclear factor-erythroid 2-related factor 2) antioxidant response pathway. These data are the first to show induction of the UPRMT in a mammalian model of decreased COX activity. In addition, the results of the present study suggest that impaired mitochondrial function can lead to induction of mitochondrial stress pathways to confer protective effects on cellular homoeostasis.
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Affiliation(s)
- Daniel A. Pulliam
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229
| | - Sathyaseelan S. Deepa
- Oklahoma Medical Research Foundation, Free Radical Biology & Aging Research Program, 825NE 13 Street, Oklahoma City, OK 73104
| | - Yuhong Liu
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229
| | - Shauna Hill
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229
| | - Ai-Ling Lin
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229
- Sanders-Brown Center on Aging, Department of Molecular and Biomedical Pharmacology, University of Kentucky
| | - Arunabh Bhattacharya
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229
| | - Yun Shi
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229
| | - Lauren Sloane
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245
| | - Carlo Viscomi
- Molecular Neurogenetics Unit, Instituto Neurologico “C. Besta”, via Temolo 4, 20126 Milano, Italy
- MRC-Mitochondrial Biology Unit, Cambridge, UK
| | - Massimo Zeviani
- Molecular Neurogenetics Unit, Instituto Neurologico “C. Besta”, via Temolo 4, 20126 Milano, Italy
- MRC-Mitochondrial Biology Unit, Cambridge, UK
| | - Holly Van Remmen
- Oklahoma Medical Research Foundation, Free Radical Biology & Aging Research Program, 825NE 13 Street, Oklahoma City, OK 73104
- Oklahoma City VA Medical Center, 921 NE 13 Street, Oklahoma City, OK 73104
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222
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López LC, Luna-Sánchez M, García-Corzo L, Quinzii CM, Hirano M. Pathomechanisms in coenzyme q10-deficient human fibroblasts. Mol Syndromol 2014; 5:163-9. [PMID: 25126049 DOI: 10.1159/000360494] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Primary coenzyme Q10 (CoQ10) deficiency is a rare mitochondrial disorder associated with 5 major clinical phenotypes: (1) encephalomyopathy, (2) severe infantile multisystemic disease, (3) cerebellar ataxia, (4) isolated myopathy, and (5) steroid-resistant nephrotic syndrome. Growth retardation, deafness and hearing loss have also been described in CoQ10-deficient patients. This heterogeneity in the clinical presentations suggests that multiple pathomechanisms may exist. To investigate the biochemical and molecular consequences of CoQ10 deficiency, different laboratories have studied cultures of skin fibroblasts from patients with CoQ10 deficiency. In this review, we summarize the results obtained in these studies over the last decade.
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Affiliation(s)
- Luis C López
- Department of Physiology, Faculty of Medicine, University of Granada, Granada, Spain ; Institute of Biotechnology, Biomedical Research Center, University of Granada, Granada, Spain
| | - Marta Luna-Sánchez
- Department of Physiology, Faculty of Medicine, University of Granada, Granada, Spain ; Institute of Biotechnology, Biomedical Research Center, University of Granada, Granada, Spain
| | - Laura García-Corzo
- Department of Physiology, Faculty of Medicine, University of Granada, Granada, Spain ; Institute of Biotechnology, Biomedical Research Center, University of Granada, Granada, Spain
| | - Catarina M Quinzii
- Department of Neurology, Columbia University Medical Center, New York, N.Y., USA
| | - Michio Hirano
- Department of Neurology, Columbia University Medical Center, New York, N.Y., USA
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223
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Burman JL, Itsara LS, Kayser EB, Suthammarak W, Wang AM, Kaeberlein M, Sedensky MM, Morgan PG, Pallanck LJ. A Drosophila model of mitochondrial disease caused by a complex I mutation that uncouples proton pumping from electron transfer. Dis Model Mech 2014; 7:1165-74. [PMID: 25085991 PMCID: PMC4174527 DOI: 10.1242/dmm.015321] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mutations affecting mitochondrial complex I, a multi-subunit assembly that couples electron transfer to proton pumping, are the most frequent cause of heritable mitochondrial diseases. However, the mechanisms by which complex I dysfunction results in disease remain unclear. Here, we describe a Drosophila model of complex I deficiency caused by a homoplasmic mutation in the mitochondrial-DNA-encoded NADH dehydrogenase subunit 2 (ND2) gene. We show that ND2 mutants exhibit phenotypes that resemble symptoms of mitochondrial disease, including shortened lifespan, progressive neurodegeneration, diminished neural mitochondrial membrane potential and lower levels of neural ATP. Our biochemical studies of ND2 mutants reveal that complex I is unable to efficiently couple electron transfer to proton pumping. Thus, our study provides evidence that the ND2 subunit participates directly in the proton pumping mechanism of complex I. Together, our findings support the model that diminished respiratory chain activity, and consequent energy deficiency, are responsible for the pathogenesis of complex-I-associated neurodegeneration.
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Affiliation(s)
- Jonathon L Burman
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Leslie S Itsara
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA. Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Ernst-Bernhard Kayser
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Wichit Suthammarak
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Adrienne M Wang
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Margaret M Sedensky
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Philip G Morgan
- Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101, USA.
| | - Leo J Pallanck
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA.
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224
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Felici R, Cavone L, Lapucci A, Guasti D, Bani D, Chiarugi A. PARP inhibition delays progression of mitochondrial encephalopathy in mice. Neurotherapeutics 2014; 11:651-64. [PMID: 24935635 PMCID: PMC4121448 DOI: 10.1007/s13311-014-0285-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial disorders are deadly childhood diseases for which therapeutic remedies are an unmet need. Given that genetic suppression of the nuclear enzyme poly (adenine diphosphate-ribose) polymerase(PARP)-1 improves mitochondrial functioning, we investigated whether pharmacological inhibition of the enzyme affords protection in a mouse model of a mitochondrial disorder. We used mice lacking the Ndufs4 subunit of the respiratory complex I (Ndufs4 knockout [ KO] mice); these mice undergo progressive encephalopathy and die around postnatal day 50. Mice were treated daily with the potent PARP inhibitor N-(6-oxo-5,6-dihydrophenanthridin-2-yl)-(N,N-dimethylamino)acetamide hydrochloride (PJ34); neurological parameters, PARP activity, and mitochondrial homeostasis were evaluated. We found that mice receiving N-(6-oxo-5,6-dihydrophenanthridin-2-yl)-(N,N-dimethylamino)acetamide hydrochloride from postnatal day 30 to postnatal day 50 show reduced neurological impairment, and increased exploratory activity and motor skills compared with vehicle-treated animals. However, drug treatment did not delay or reduce death. We found no evidence of increased PARP activity within the brain of KO mice compared with heterozygous, healthy controls. Conversely, a 10-day treatment with the PARP inhibitor significantly reduced basal poly(ADP-ribosyl)ation in different organs of the KO mice, including brain, skeletal muscle, liver, pancreas, and spleen. In keeping with the epigenetic role of PARP-1, its inhibition correlated with increased expression of mitochondrial respiratory complex subunits and organelle number. Remarkably, pharmacological targeting of PARP reduced astrogliosis in olfactory bulb and motor cortex, but did not affect neuronal loss of KO mice. In light of the advanced clinical development of PARP inhibitors, these data emphasize their relevance to treatment of mitochondrial respiratory defects.
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Affiliation(s)
- Roberta Felici
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, Florence, 50139, Italy,
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225
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Hong J, Kim BW, Choo HJ, Park JJ, Yi JS, Yu DM, Lee H, Yoon GS, Lee JS, Ko YG. Mitochondrial complex I deficiency enhances skeletal myogenesis but impairs insulin signaling through SIRT1 inactivation. J Biol Chem 2014; 289:20012-25. [PMID: 24895128 DOI: 10.1074/jbc.m114.560078] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
To address whether mitochondrial biogenesis is essential for skeletal myogenesis, C2C12 myogenesis was investigated after knockdown of NADH dehydrogenase (ubiquintone) flavoprotein 1 (NDUFV1), which is an oxidative phosphorylation complex I subunit that is the first subunit to accept electrons from NADH. The NDUFVI knockdown enhanced C2C12 myogenesis by decreasing the NAD(+)/NADH ratio and subsequently inactivating SIRT1 and SIRT1 activators (pyruvate, SRT1720, and resveratrol) abolished the NDUFV1 knockdown-induced myogenesis enhancement. However, the insulin-elicited activation of insulin receptor β (IRβ) and insulin receptor substrate-1 (IRS-1) was reduced with elevated levels of protein-tyrosine phosphatase 1B after NDUFV1 knockdown in C2C12 myotubes. The NDUFV1 knockdown-induced blockage of insulin signaling was released by protein-tyrosine phosphatase 1B knockdown in C2C12 myotubes, and we found that NDUFV1 or SIRT1 knockdown did not affect mitochondria biogenesis during C2C12 myogenesis. Based on these data, we can conclude that complex I dysfunction-induced SIRT1 inactivation leads to myogenesis enhancement but blocks insulin signaling without affecting mitochondria biogenesis.
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Affiliation(s)
- Jin Hong
- From the Division of Life Sciences, Korea University, Seoul, 136-701, Korea
| | - Bong-Woo Kim
- Department of Cosmetic Science and Technology, Seowon University, Cheongju, 361-742, Korea
| | - Hyo-Jung Choo
- From the Division of Life Sciences, Korea University, Seoul, 136-701, Korea
| | - Jung-Jin Park
- From the Division of Life Sciences, Korea University, Seoul, 136-701, Korea
| | - Jae-Sung Yi
- From the Division of Life Sciences, Korea University, Seoul, 136-701, Korea
| | - Dong-Min Yu
- From the Division of Life Sciences, Korea University, Seoul, 136-701, Korea
| | - Hyun Lee
- From the Division of Life Sciences, Korea University, Seoul, 136-701, Korea
| | - Gye-Soon Yoon
- Department of Biochemistry and Molecular Biology, Ajou University, Suwon 443-721, Korea, and
| | - Jae-Seon Lee
- Department of Biomedical Sciences, College of Medicine, Inha University, Incheon, 400-712, Korea
| | - Young-Gyu Ko
- From the Division of Life Sciences, Korea University, Seoul, 136-701, Korea,
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226
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Acín-Pérez R, Carrascoso I, Baixauli F, Roche-Molina M, Latorre-Pellicer A, Fernández-Silva P, Mittelbrunn M, Sanchez-Madrid F, Pérez-Martos A, Lowell CA, Manfredi G, Enríquez JA. ROS-triggered phosphorylation of complex II by Fgr kinase regulates cellular adaptation to fuel use. Cell Metab 2014; 19:1020-33. [PMID: 24856931 PMCID: PMC4274740 DOI: 10.1016/j.cmet.2014.04.015] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 02/13/2014] [Accepted: 04/03/2014] [Indexed: 11/27/2022]
Abstract
Electron flux in the mitochondrial electron transport chain is determined by the superassembly of mitochondrial respiratory complexes. Different superassemblies are dedicated to receive electrons derived from NADH or FADH2, allowing cells to adapt to the particular NADH/FADH2 ratio generated from available fuel sources. When several fuels are available, cells adapt to the fuel best suited to their type or functional status (e.g., quiescent versus proliferative). We show that an appropriate proportion of superassemblies can be achieved by increasing CII activity through phosphorylation of the complex II catalytic subunit FpSDH. This phosphorylation is mediated by the tyrosine-kinase Fgr, which is activated by hydrogen peroxide. Ablation of Fgr or mutation of the FpSDH target tyrosine abolishes the capacity of mitochondria to adjust metabolism upon nutrient restriction, hypoxia/reoxygenation, and T cell activation, demonstrating the physiological relevance of this adaptive response.
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Affiliation(s)
- Rebeca Acín-Pérez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Isabel Carrascoso
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Francesc Baixauli
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Marta Roche-Molina
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Ana Latorre-Pellicer
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Patricio Fernández-Silva
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - María Mittelbrunn
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Francisco Sanchez-Madrid
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Acisclo Pérez-Martos
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Clifford A Lowell
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Giovanni Manfredi
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - José Antonio Enríquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro, 3, 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain.
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227
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Morató L, Bertini E, Verrigni D, Ardissone A, Ruiz M, Ferrer I, Uziel G, Pujol A. Mitochondrial dysfunction in central nervous system white matter disorders. Glia 2014; 62:1878-94. [DOI: 10.1002/glia.22670] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 03/20/2014] [Accepted: 03/21/2014] [Indexed: 12/26/2022]
Affiliation(s)
- Laia Morató
- Neurometabolic Diseases Laboratory; Bellvitge Biomedical Research Institute (IDIBELL); L'Hospitalet de Llobregat Barcelona Spain
- Center for Biomedical Research on Rare Diseases (CIBERER); ISCIII Spain
| | - Enrico Bertini
- Unit for Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital; IRCCS Rome Italy
| | - Daniela Verrigni
- Unit for Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital; IRCCS Rome Italy
| | - Anna Ardissone
- Department of Child Neurology The Foundation “Carlo Besta” Neurological Institute (IRCCS); Milan Italy
| | - Montse Ruiz
- Neurometabolic Diseases Laboratory; Bellvitge Biomedical Research Institute (IDIBELL); L'Hospitalet de Llobregat Barcelona Spain
- Center for Biomedical Research on Rare Diseases (CIBERER); ISCIII Spain
| | - Isidre Ferrer
- Institute of Neuropathology, University of Barcelona, L'Hospitalet de Llobregat; Barcelona Spain
- Center for Biomedical Research on Neurodegenerative Diseases (CIBERNED); ISCIII Spain
| | - Graziella Uziel
- Department of Child Neurology The Foundation “Carlo Besta” Neurological Institute (IRCCS); Milan Italy
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory; Bellvitge Biomedical Research Institute (IDIBELL); L'Hospitalet de Llobregat Barcelona Spain
- Center for Biomedical Research on Rare Diseases (CIBERER); ISCIII Spain
- Catalan Institution of Research and Advanced Studies (ICREA); Barcelona Spain
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228
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Chouchani ET, Methner C, Buonincontri G, Hu CH, Logan A, Sawiak SJ, Murphy MP, Krieg T. Complex I deficiency due to selective loss of Ndufs4 in the mouse heart results in severe hypertrophic cardiomyopathy. PLoS One 2014; 9:e94157. [PMID: 24705922 PMCID: PMC3976382 DOI: 10.1371/journal.pone.0094157] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 03/11/2014] [Indexed: 01/07/2023] Open
Abstract
Mitochondrial complex I, the primary entry point for electrons into the mitochondrial respiratory chain, is both critical for aerobic respiration and a major source of reactive oxygen species. In the heart, chronic dysfunction driving cardiomyopathy is frequently associated with decreased complex I activity, from both genetic and environmental causes. To examine the functional relationship between complex I disruption and cardiac dysfunction we used an established mouse model of mild and chronic complex I inhibition through heart-specific Ndufs4 gene ablation. Heart-specific Ndufs4-null mice had a decrease of ∼50% in complex I activity within the heart, and developed severe hypertrophic cardiomyopathy as assessed by magnetic resonance imaging. The decrease in complex I activity, and associated cardiac dysfunction, occurred absent an increase in mitochondrial hydrogen peroxide levels in vivo, accumulation of markers of oxidative damage, induction of apoptosis, or tissue fibrosis. Taken together, these results indicate that diminished complex I activity in the heart alone is sufficient to drive hypertrophic cardiomyopathy independently of alterations in levels of mitochondrial hydrogen peroxide or oxidative damage.
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Affiliation(s)
- Edward T. Chouchani
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- MRC Mitochondrial Biology Unit, Cambridge, United Kingdom
| | - Carmen Methner
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Chou-Hui Hu
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Angela Logan
- MRC Mitochondrial Biology Unit, Cambridge, United Kingdom
| | - Stephen J. Sawiak
- Wolfson Brain Imaging Centre, University of Cambridge, United Kingdom
| | | | - Thomas Krieg
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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229
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Rygiel KA, Grady JP, Turnbull DM. Respiratory chain deficiency in aged spinal motor neurons. Neurobiol Aging 2014; 35:2230-8. [PMID: 24684792 PMCID: PMC4099519 DOI: 10.1016/j.neurobiolaging.2014.02.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 01/13/2014] [Accepted: 02/27/2014] [Indexed: 01/10/2023]
Abstract
Sarcopenia, muscle wasting, and strength decline with age, is an important cause of loss of mobility in the elderly individuals. The underlying mechanisms are uncertain but likely to involve defects of motor nerve, neuromuscular junction, and muscle. Loss of motor neurons with age and subsequent denervation of skeletal muscle has been recognized as one of the contributing factors. This study investigated aspects of mitochondrial biology in spinal motor neurons from elderly subjects. We found that protein components of complex I of mitochondrial respiratory chain were reduced or absent in a proportion of aged motor neurons–a phenomenon not observed in fetal tissue. Further investigation showed that complex I-deficient cells had reduced mitochondrial DNA content and smaller soma size. We propose that mitochondrial dysfunction in these motor neurons could lead to the cell loss and ultimately denervation of muscle fibers.
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Affiliation(s)
- Karolina A Rygiel
- Newcastle University Centre for Brain Ageing and Vitality, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK; Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - John P Grady
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Doug M Turnbull
- Newcastle University Centre for Brain Ageing and Vitality, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK; Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, UK.
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230
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Gaweda-Walerych K, Zekanowski C. The impact of mitochondrial DNA and nuclear genes related to mitochondrial functioning on the risk of Parkinson's disease. Curr Genomics 2014; 14:543-59. [PMID: 24532986 PMCID: PMC3924249 DOI: 10.2174/1389202914666131210211033] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/30/2013] [Accepted: 08/29/2013] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial dysfunction and oxidative stress are the major factors implicated in Parkinson’s disease (PD)
pathogenesis. The maintenance of healthy mitochondria is a very complex process coordinated bi-genomically. Here, we
review association studies on mitochondrial haplogroups and subhaplogroups, discussing the underlying molecular
mechanisms. We also focus on variation in the nuclear genes (NDUFV2, PGC-1alpha, HSPA9, LRPPRC, MTIF3,
POLG1, and TFAM encoding NADH dehydrogenase (ubiquinone) flavoprotein 2, peroxisome proliferator-activated receptor
gamma coactivator 1-alpha, mortalin, leucine-rich pentatricopeptide repeat containing protein, translation initiation
factor 3, mitochondrial DNA polymerase gamma, and mitochondrial transcription factor A, respectively) primarily linked
to regulation of mitochondrial functioning that recently have been associated with PD risk. Possible interactions between
mitochondrial and nuclear genetic variants and related proteins are discussed.
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Affiliation(s)
- Katarzyna Gaweda-Walerych
- Laboratory of Neurogenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5 str., 02-106 Warszawa, Poland
| | - Cezary Zekanowski
- Laboratory of Neurogenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5 str., 02-106 Warszawa, Poland
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231
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Isoflurane anesthetic hypersensitivity and progressive respiratory depression in a mouse model with isolated mitochondrial complex I deficiency. J Anesth 2014; 28:807-14. [PMID: 24522811 DOI: 10.1007/s00540-014-1791-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 01/10/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND Children with mitochondrial disorders are frequently anesthetized for a wide range of operations. These disorders may interfere with the response to surgery and anesthesia. We examined anesthetic sensitivity to and respiratory effects of isoflurane in the Ndufs4 knockout (KO) mouse model. These mice exhibit an isolated mitochondrial complex I (CI) deficiency of the respiratory chain, and they also display clinical signs and symptoms resembling those of patients with mitochondrial CI disease. METHODS We investigated seven Ndufs4(-/-) knockout (KO), five Ndufs4(+/-) heterozygous (HZ) and five Ndufs4(+/+) wild type (WT) mice between 22 and 25 days and again between 31 and 34 days post-natal. Animals were placed inside an airtight box, breathing spontaneously while isoflurane was administered in increasing concentrations. Minimum alveolar concentration (MAC) was determined with the bracketing study design, using the response to electrical stimulation to the hind paw. RESULTS MAC for isoflurane was significantly lower in KO mice than in HZ and WT mice: 0.81% ± 0.01 vs 1.55 ± 0.05% and 1.55 ± 0.13%, respectively, at 22-25 days, and 0.65 ± 0.05%, 1.65 ± 0.08% and 1.68 ± 0.08% at 31-34 days. The KO mice showed severe respiratory depression at lower isoflurane concentrations than the WT and HZ mice. CONCLUSION We observed an increased isoflurane anesthetic sensitivity and severe respiratory depression in the KO mice. The respiratory depression during anesthesia was strongly progressive with age. Since the pathophysiological consequences from complex I deficiency are mainly reflected in the central nervous system and our mouse model involves progressive encephalopathy, further investigation of isoflurane effects on brain mitochondrial function is warranted.
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232
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Affiliation(s)
- Scott B Vafai
- Howard Hughes Medical Institute, Departments of Molecular Biology and Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
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233
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Johnson SC, Yanos ME, Kayser EB, Quintana A, Sangesland M, Castanza A, Uhde L, Hui J, Wall VZ, Gagnidze A, Oh K, Wasko BM, Ramos FJ, Palmiter RD, Rabinovitch PS, Morgan PG, Sedensky MM, Kaeberlein M. mTOR inhibition alleviates mitochondrial disease in a mouse model of Leigh syndrome. Science 2013; 342:1524-8. [PMID: 24231806 PMCID: PMC4055856 DOI: 10.1126/science.1244360] [Citation(s) in RCA: 397] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Mitochondrial dysfunction contributes to numerous health problems, including neurological and muscular degeneration, cardiomyopathies, cancer, diabetes, and pathologies of aging. Severe mitochondrial defects can result in childhood disorders such as Leigh syndrome, for which there are no effective therapies. We found that rapamycin, a specific inhibitor of the mechanistic target of rapamycin (mTOR) signaling pathway, robustly enhances survival and attenuates disease progression in a mouse model of Leigh syndrome. Administration of rapamycin to these mice, which are deficient in the mitochondrial respiratory chain subunit Ndufs4 [NADH dehydrogenase (ubiquinone) Fe-S protein 4], delays onset of neurological symptoms, reduces neuroinflammation, and prevents brain lesions. Although the precise mechanism of rescue remains to be determined, rapamycin induces a metabolic shift toward amino acid catabolism and away from glycolysis, alleviating the buildup of glycolytic intermediates. This therapeutic strategy may prove relevant for a broad range of mitochondrial diseases.
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Affiliation(s)
- Simon C. Johnson
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Melana E. Yanos
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
- Department of Psychology, University of Washington, Seattle, WA 98195, USA
| | - Ernst-Bernhard Kayser
- Anesthesiology and Pain Medicine, Seattle Children’s Hospital, Seattle, WA 98105, USA
| | - Albert Quintana
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Maya Sangesland
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Anthony Castanza
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Lauren Uhde
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Jessica Hui
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Valerie Z. Wall
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Arni Gagnidze
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Kelly Oh
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Brian M. Wasko
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Fresnida J. Ramos
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Richard D. Palmiter
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | | | - Philip G. Morgan
- Anesthesiology and Pain Medicine, Seattle Children’s Hospital, Seattle, WA 98105, USA
| | - Margaret M. Sedensky
- Anesthesiology and Pain Medicine, Seattle Children’s Hospital, Seattle, WA 98105, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
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234
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Morgan PG, Kayser EB, Sedensky M. Region specific differences in oxidative phosphorylation in mitochondria from Ndufs4 knockout mice. Mitochondrion 2013. [DOI: 10.1016/j.mito.2013.07.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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235
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Kayser EB, Johnson SC, Kaeberlein MR, Sedensky MM, Morgan PG. Capacity for oxidative phosphorylation does not decline with age in mitochondria from ndufs4 knockout mice. Mitochondrion 2013. [DOI: 10.1016/j.mito.2013.07.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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236
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Bird MJ, Thorburn DR, Frazier AE. Modelling biochemical features of mitochondrial neuropathology. Biochim Biophys Acta Gen Subj 2013; 1840:1380-92. [PMID: 24161927 DOI: 10.1016/j.bbagen.2013.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 08/29/2013] [Accepted: 10/11/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND The neuropathology of mitochondrial disease is well characterised. However, pathophysiological mechanisms at the level of biochemistry and cell biology are less clear. Progress in this area has been hampered by the limited accessibility of neurologically relevant material for analysis. SCOPE OF REVIEW Here we discuss the recent development of a variety of model systems that have greatly extended our capacity to understand the biochemical features associated with mitochondrial neuropathology. These include animal and cell based models, with mutations in both nuclear and mitochondrial DNA encoded genes, which aim to recapitulate the neuropathology and cellular biochemistry of mitochondrial diseases. MAJOR CONCLUSIONS Analysis of neurological tissue and cells from these models suggests that although there is no unifying mode of pathogenesis, dysfunction of the oxidative phosphorylation (OXPHOS) system is often central. This can be associated with altered reactive oxygen species (ROS) generation, disruption of the mitochondrial membrane potential (ΔΨm) and inadequate ATP synthesis. Thus, other cellular processes such as calcium (Ca(2+)) homeostasis, cellular signaling and mitochondrial morphology could be altered, ultimately compromising viability of neuronal cells. GENERAL SIGNIFICANCE Mechanisms of neuronal dysfunction in mitochondrial disease are only just beginning to be characterised, are system dependent and complex, and not merely driven by energy deficiency. The diversity of pathogenic mechanisms emphasises the need for characterisation in a wide range of models, as different therapeutic strategies are likely to be needed for different diseases. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Matthew J Bird
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia
| | - David R Thorburn
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia; Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia
| | - Ann E Frazier
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia.
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Peralta S, Torraco A, Wenz T, Garcia S, Diaz F, Moraes CT. Partial complex I deficiency due to the CNS conditional ablation of Ndufa5 results in a mild chronic encephalopathy but no increase in oxidative damage. Hum Mol Genet 2013; 23:1399-412. [PMID: 24154540 DOI: 10.1093/hmg/ddt526] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Deficiencies in the complex I (CI; NADH-ubiquinone oxidoreductase) of the respiratory chain are frequent causes of mitochondrial diseases and have been associated with other neurodegenerative disorders, such as Parkinson's disease. The NADH-ubiquinone oxidoreductase 1 alpha subcomplex subunit 5 (NDUFA5) is a nuclear-encoded structural subunit of CI, located in the peripheral arm. We inactivated Ndufa5 in mice by the gene-trap methodology and found that this protein is required for embryonic survival. Therefore, we have created a conditional Ndufa5 knockout (KO) allele by introducing a rescuing Ndufa5 cDNA transgene flanked by loxP sites, which was selectively ablated in neurons by the CaMKIIα-Cre. At the age of 11 months, mice with a central nervous system knockout of Ndufa5 (Ndufa5 CNS-KO) showed lethargy and loss of motor skills. In these mice cortices, the levels of NDUFA5 protein were reduced to 25% of controls. Fully assembled CI levels were also greatly reduced in cortex and CI activity in homogenates was reduced to 60% of controls. Despite the biochemical phenotype, no oxidative damage, neuronal death or gliosis were detected in the Ndufa5 CNS-KO brain at this age. These results showed that a partial defect in CI in neurons can lead to late-onset motor phenotypes without neuronal loss or oxidative damage.
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238
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Pathak D, Berthet A, Nakamura K. Energy failure: does it contribute to neurodegeneration? Ann Neurol 2013; 74:506-16. [PMID: 24038413 PMCID: PMC4092015 DOI: 10.1002/ana.24014] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 08/09/2013] [Accepted: 08/16/2013] [Indexed: 12/11/2022]
Abstract
Energy failure from mitochondrial dysfunction is proposed to be a central mechanism leading to neuronal death in a range of neurodegenerative diseases. However, energy failure has never been directly demonstrated in affected neurons in these diseases, nor has it been proved to produce degeneration in disease models. Therefore, despite considerable indirect evidence, it is not known whether energy failure truly occurs in susceptible neurons, and whether this failure is responsible for their death. This limited understanding results primarily from a lack of sensitivity and resolution of available tools and assays and the inherent limitations of in vitro model systems. Major advances in these methodologies and approaches should greatly enhance our understanding of the relationship between energy failure, neuronal dysfunction, and death, and help us to determine whether boosting bioenergetic function would be an effective therapeutic approach. Here we review the current evidence that energy failure occurs in and contributes to neurodegenerative disease, and consider new approaches that may allow us to better address this central issue.
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Affiliation(s)
- Divya Pathak
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA
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Schlehe JS, Journel MSM, Taylor KP, Amodeo KD, LaVoie MJ. The mitochondrial disease associated protein Ndufaf2 is dispensable for Complex-1 assembly but critical for the regulation of oxidative stress. Neurobiol Dis 2013; 58:57-67. [PMID: 23702311 PMCID: PMC3748239 DOI: 10.1016/j.nbd.2013.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 05/03/2013] [Accepted: 05/10/2013] [Indexed: 02/03/2023] Open
Abstract
Deficiency in human mitochondrial Complex-1 has been linked to a wide variety of neurological disorders. Homozygous deletion of the Complex-1 associated protein, Ndufaf2, leads to a severe juvenile onset encephalopathy involving degeneration of the substantia nigra and other sub-cortical regions resulting in adolescent lethality. To understand the precise role of Ndufaf2 in Complex-1 function and its links to neurologic disease, we studied the effects on Complex-1 assembly and function, as well as pathological consequences at the cellular level, in multiple in vitro models of Ndufaf2 deficiency. Using both Ndufaf2-deficient human neuroblastoma cells and primary fibroblasts cultured from Ndufaf2 knock-out mice we found that Ndufaf2-deficiency selectively reduces Complex-1 activity. While Ndufaf2 is traditionally referred to as an assembly factor of Complex-1, surprisingly, however, Ndufaf2-deficient cells were able to assemble a fully mature Complex-1 enzyme, albeit with reduced kinetics. Importantly, no evidence of intermediate or incomplete assembly was observed. Ndufaf2 deficiency resulted in significant increases in oxidative stress and mitochondrial DNA deletion, consistent with contemporary hypotheses regarding the pathophysiology of inherited mutations in Complex-1 disorders. These data suggest that Ndufaf2, unlike other Complex-1 assembly factors, may be more accurately described as a chaperone involved in proper folding during Complex-1 assembly, since it is dispensable for Complex-1 maturation but not its proper function.
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Affiliation(s)
- Julia S Schlehe
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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240
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Pirola CJ, Gianotti TF, Burgueño AL, Rey-Funes M, Loidl CF, Mallardi P, Martino JS, Castaño GO, Sookoian S. Epigenetic modification of liver mitochondrial DNA is associated with histological severity of nonalcoholic fatty liver disease. Gut 2013; 62:1356-63. [PMID: 22879518 DOI: 10.1136/gutjnl-2012-302962] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE & DESIGN Nonalcoholic fatty liver disease (NAFLD) is a clinical condition that refers to progressive histological changes ranging from simple steatosis (SS) to nonalcoholic steatohepatitis (NASH). We evaluated the status of cytosine methylation (5mC) of liver mitochondrial DNA (mtDNA) in selected regions of the mtDNA genome, such as D-loop control region, and mitochondrially encoded NADH dehydrogenase 6 (MT-ND6) and cytochrome C oxidase I (MT-CO1), to contrast the hypothesis that epigenetic modifications play a role in the phenotypic switching from SS to NASH. METHODS We studied liver biopsies obtained from patients with NAFLD in a case-control design; 45 patients and 18 near-normal liver-histology subjects. RESULTS MT-ND6 methylation was higher in the liver of NASH than SS patients (p < 0.04) and MT-ND6 methylated DNA/unmethylated DNA ratio was significantly associated with NAFLD activity score (p < 0.02). Liver MT-ND6 mRNA expression was significantly decreased in NASH patients (0.26 ± 0.30) versus SS (0.74 ± 0.48), p < 0.003, and the protein level was also diminished. The status of liver MT-ND6 methylation in NASH group was inversely correlated with the level of regular physical activity (R = -0.54, p < 0.02). Hepatic methylation levels of D-Loop and MT-CO1 were not associated with the disease severity. DNA (cytosine-5) methyltransferase 1 was significantly upregulated in NASH patients (p < 0.002). Ultrastructural evaluation showed that NASH is associated with mitochondrial defects and peroxisome proliferation. CONCLUSION Hepatic methylation and transcriptional activity of the MT-ND6 are associated with the histological severity of NAFLD. Epigenetic changes of mtDNA are potentially reversible by interventional programs, as physical activity could modulate the methylation status of MT-ND6.
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Affiliation(s)
- Carlos Jose Pirola
- Department of Molecular Genetics and Biology of the Complex Diseases, Institute of Medical Research A Lanari-IDIM, University of Buenos Aires-National Council of Scientific and Technological Research (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
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Karamanlidis G, Lee CF, Garcia-Menendez L, Kolwicz SC, Suthammarak W, Gong G, Sedensky MM, Morgan PG, Wang W, Tian R. Mitochondrial complex I deficiency increases protein acetylation and accelerates heart failure. Cell Metab 2013; 18:239-50. [PMID: 23931755 PMCID: PMC3779647 DOI: 10.1016/j.cmet.2013.07.002] [Citation(s) in RCA: 338] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/22/2013] [Accepted: 07/02/2013] [Indexed: 01/04/2023]
Abstract
Mitochondrial respiratory dysfunction is linked to the pathogenesis of multiple diseases, including heart failure, but the specific mechanisms for this link remain largely elusive. We modeled the impairment of mitochondrial respiration by the inactivation of the Ndufs4 gene, a protein critical for complex I assembly, in the mouse heart (cKO). Although complex I-supported respiration decreased by >40%, the cKO mice maintained normal cardiac function in vivo and high-energy phosphate content in isolated perfused hearts. However, the cKO mice developed accelerated heart failure after pressure overload or repeated pregnancy. Decreased NAD(+)/NADH ratio by complex I deficiency inhibited Sirt3 activity, leading to an increase in protein acetylation and sensitization of the permeability transition in mitochondria (mPTP). NAD(+) precursor supplementation to cKO mice partially normalized the NAD(+)/NADH ratio, protein acetylation, and mPTP sensitivity. These findings describe a mechanism connecting mitochondrial dysfunction to the susceptibility to diseases and propose a potential therapeutic target.
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Affiliation(s)
- Georgios Karamanlidis
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, 98109, USA
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242
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Subramaniam SR, Chesselet MF. Mitochondrial dysfunction and oxidative stress in Parkinson's disease. Prog Neurobiol 2013; 106-107:17-32. [PMID: 23643800 PMCID: PMC3742021 DOI: 10.1016/j.pneurobio.2013.04.004] [Citation(s) in RCA: 521] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/13/2013] [Accepted: 04/22/2013] [Indexed: 12/12/2022]
Abstract
Parkinson's disease (PD) is a movement disorder that is characterized by the progressive degeneration of dopaminergic neurons in substantia nigra pars compacta resulting in dopamine deficiency in the striatum. Although majority of the PD cases are sporadic several genetic mutations have also been linked to the disease thus providing new opportunities to study the pathology of the illness. Studies in humans and various animal models of PD reveal that mitochondrial dysfunction might be a defect that occurs early in PD pathogenesis and appears to be a widespread feature in both sporadic and monogenic forms of PD. The general mitochondrial abnormalities linked with the disease include mitochondrial electron transport chain impairment, alterations in mitochondrial morphology and dynamics, mitochondrial DNA mutations and anomaly in calcium homeostasis. Mitochondria are vital organelles with multiple functions and their dysfunction can lead to a decline in energy production, generation of reactive oxygen species and induction of stress-induced apoptosis. In this review, we give an outline of mitochondrial functions that are affected in the pathogenesis of sporadic and familial PD, and hence provide insights that might be valuable for focused future research to exploit possible mitochondrial targets for neuroprotective interventions in PD.
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Affiliation(s)
- Sudhakar Raja Subramaniam
- Department of Neurology, David Geffen School of Medicine, UCLA, 710 Westwood Plaza, Los Angeles, CA 90095-1769, USA
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243
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Mitochondrial disorders: aetiologies, models systems, and candidate therapies. Trends Genet 2013; 29:488-97. [PMID: 23756086 DOI: 10.1016/j.tig.2013.05.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 05/01/2013] [Accepted: 05/03/2013] [Indexed: 01/14/2023]
Abstract
It has become evident that many human disorders are characterised by mitochondrial dysfunction either at a primary level, due to mutations in genes whose encoded products are involved in oxidative phosphorylation, or at a secondary level, due to the accumulation of mitochondrial DNA (mtDNA) mutations. This has prompted keen interest in the development of cell and animal models and in exploring innovative therapeutic strategies to modulate the mitochondrial deficiencies observed in these diseases. Key advances in these areas are outlined in this review, with a focus on Leber hereditary optic neuropathy (LHON). This exciting field is set to grow exponentially and yield many candidate therapies to treat this class of disease.
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244
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Breuer ME, Willems PHGM, Smeitink JAM, Koopman WJH, Nooteboom M. Cellular and animal models for mitochondrial complex I deficiency: a focus on the NDUFS4 subunit. IUBMB Life 2013; 65:202-8. [PMID: 23378164 DOI: 10.1002/iub.1127] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 12/04/2012] [Indexed: 11/07/2022]
Abstract
To allow the rational design of effective treatment strategies for human mitochondrial disorders, a proper understanding of their biochemical and pathophysiological aspects is required. The development and evaluation of these strategies require suitable model systems. In humans, inherited complex I (CI) deficiency is one of the most common deficiencies of the mitochondrial oxidative phosphorylation system. During the last decade, various cellular and animal models of CI deficiency have been presented involving mutations and/or deletion of the Ndufs4 gene, which encodes the NDUFS4 subunit of CI. In this review, we discuss these models and their validity for studying human CI deficiency.
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Affiliation(s)
- Megan E Breuer
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
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245
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246
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Papa S, De Rasmo D. Complex I deficiencies in neurological disorders. Trends Mol Med 2012; 19:61-9. [PMID: 23265841 DOI: 10.1016/j.molmed.2012.11.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/18/2012] [Accepted: 11/15/2012] [Indexed: 12/14/2022]
Abstract
Complex I is the point of entry in the mitochondrial electron transport chain for NADH reducing equivalents, and it behaves as a regulatable pacemaker of respiratory ATP production in human cells. Defects in complex I are associated with several human neurological disorders, including primary mitochondrial diseases, Parkinson disease (PD), and Down syndrome, and understanding the activity and regulation of complex I may reveal aspects of the underlying pathogenic mechanisms. Complex I is regulated by cyclic AMP (cAMP) and the protein kinase A (PKA) signal transduction pathway, and elucidating the role of the cAMP/PKA system in regulating complex I and oxygen free radical production provides new perspectives for devising therapeutic strategies for neurological diseases.
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Affiliation(s)
- Sergio Papa
- Institute of Biomembranes and Bioenergetics (IBBE), Consiglio Nazionale delle Ricerche, Bari, Italy.
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247
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García-Corzo L, Luna-Sánchez M, Doerrier C, García JA, Guarás A, Acín-Pérez R, Bullejos-Peregrín J, López A, Escames G, Enríquez JA, Acuña-Castroviejo D, López LC. Dysfunctional Coq9 protein causes predominant encephalomyopathy associated with CoQ deficiency. Hum Mol Genet 2012; 22:1233-48. [PMID: 23255162 DOI: 10.1093/hmg/dds530] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Coenzyme Q10 (CoQ(10)) or ubiquinone is a well-known component of the mitochondrial respiratory chain. In humans, CoQ(10) deficiency causes a mitochondrial syndrome with an unexplained variability in the clinical presentations. To try to understand this heterogeneity in the clinical phenotypes, we have generated a Coq9 Knockin (R239X) mouse model. The lack of a functional Coq9 protein in homozygous Coq9 mutant (Coq9(X/X)) mice causes a severe reduction in the Coq7 protein and, as consequence, a widespread CoQ deficiency and accumulation of demethoxyubiquinone. The deficit in CoQ induces a brain-specific impairment of mitochondrial bioenergetics performance, a reduction in respiratory control ratio, ATP levels and ATP/ADP ratio and specific loss of respiratory complex I. These effects lead to neuronal death and demyelinization with severe vacuolization and astrogliosis in the brain of Coq9(X/X) mice that consequently die between 3 and 6 months of age. These results suggest that the instability of mitochondrial complex I in the brain, as a primary event, triggers the development of mitochondrial encephalomyopathy associated with CoQ deficiency.
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Affiliation(s)
- Laura García-Corzo
- Instituto de Biotecnologı´a, Centro de Investigacio´n Biome´dica, Parque Tecnolo´gico de Ciencias de la Salud, Armilla, Granada, Spain
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248
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Deepa SS, Pulliam D, Hill S, Shi Y, Walsh ME, Salmon A, Sloane L, Zhang N, Zeviani M, Viscomi C, Musi N, Van Remmen H. Improved insulin sensitivity associated with reduced mitochondrial complex IV assembly and activity. FASEB J 2012; 27:1371-80. [PMID: 23241310 DOI: 10.1096/fj.12-221879] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Mice lacking Surf1, a complex IV assembly protein, have ∼50-70% reduction in cytochrome c oxidase activity in all tissues yet a paradoxical increase in lifespan. Here we report that Surf1(-/-) mice have lower body (15%) and fat (20%) mass, in association with reduced lipid storage, smaller adipocytes, and elevated indicators of fatty acid oxidation in white adipose tissue (WAT) compared with control mice. The respiratory quotient in the Surf1(-/-) mice was significantly lower than in the control animals (0.83-0.93 vs. 0.90-0.98), consistent with enhanced fat utilization in Surf1(-/-) mice. Elevated fat utilization was associated with increased insulin sensitivity measured as insulin-stimulated glucose uptake, as well as an increase in insulin receptor levels (∼2-fold) and glucose transporter type 4 (GLUT4; ∼1.3-fold) levels in WAT in the Surf1(-/-) mice. The expression of peroxisome proliferator-activated receptor γ-coactivator 1-α (PGC-1α) mRNA and protein was up-regulated by 2.5- and 1.9-fold, respectively, in WAT from Surf1(-/-) mice, and the expression of PGC-1α target genes and markers of mitochondrial biogenesis was elevated. Together, these findings point to a novel and unexpected link between reduced mitochondrial complex IV activity, enhanced insulin sensitivity, and increased mitochondrial biogenesis that may contribute to the increased longevity in the Surf1(-/-) mice.
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Affiliation(s)
- Sathyaseelan S Deepa
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, TX78245, USA
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249
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Primary fibroblasts of NDUFS4(-/-) mice display increased ROS levels and aberrant mitochondrial morphology. Mitochondrion 2012; 13:436-43. [PMID: 23234723 DOI: 10.1016/j.mito.2012.12.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 11/28/2012] [Accepted: 12/03/2012] [Indexed: 11/22/2022]
Abstract
The human NDUFS4 gene encodes an accessory subunit of the first mitochondrial oxidative phosphorylation complex (CI) and, when mutated, is associated with progressive neurological disorders. Here we analyzed primary muscle and skin fibroblasts from NDUFS4(-/-) mice with respect to reactive oxygen species (ROS) levels and mitochondrial morphology. NDUFS4(-/-) fibroblasts displayed an inactive CI subcomplex on native gels but proliferated normally and showed no obvious signs of apoptosis. Oxidation of the ROS sensor hydroethidium was increased and mitochondria were less branched and/or shorter in NDUFS4(-/-) fibroblasts. We discuss the relevance of these findings with respect to previous results and therapy development.
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250
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Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) sustains organelle function and plays a central role in cellular energy metabolism. The OXPHOS system consists of 5 multisubunit complexes (CI-CV) that are built up of 92 different structural proteins encoded by the nuclear (nDNA) and mitochondrial DNA (mtDNA). Biogenesis of a functional OXPHOS system further requires the assistance of nDNA-encoded OXPHOS assembly factors, of which 35 are currently identified. In humans, mutations in both structural and assembly genes and in genes involved in mtDNA maintenance, replication, transcription, and translation induce 'primary' OXPHOS disorders that are associated with neurodegenerative diseases including Leigh syndrome (LS), which is probably the most classical OXPHOS disease during early childhood. Here, we present the current insights regarding function, biogenesis, regulation, and supramolecular architecture of the OXPHOS system, as well as its genetic origin. Next, we provide an inventory of OXPHOS structural and assembly genes which, when mutated, induce human neurodegenerative disorders. Finally, we discuss the consequences of mutations in OXPHOS structural and assembly genes at the single cell level and how this information has advanced our understanding of the role of OXPHOS dysfunction in neurodegeneration.
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