151
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Besson MT, Alegría K, Garrido-Gerter P, Barros LF, Liévens JC. Enhanced neuronal glucose transporter expression reveals metabolic choice in a HD Drosophila model. PLoS One 2015; 10:e0118765. [PMID: 25761110 PMCID: PMC4356621 DOI: 10.1371/journal.pone.0118765] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 01/06/2015] [Indexed: 11/30/2022] Open
Abstract
Huntington’s disease is a neurodegenerative disorder caused by toxic insertions of polyglutamine residues in the Huntingtin protein and characterized by progressive deterioration of cognitive and motor functions. Altered brain glucose metabolism has long been suggested and a possible link has been proposed in HD. However, the precise function of glucose transporters was not yet determined. Here, we report the effects of the specifically-neuronal human glucose transporter expression in neurons of a Drosophila model carrying the exon 1 of the human huntingtin gene with 93 glutamine repeats (HQ93). We demonstrated that overexpression of the human glucose transporter in neurons ameliorated significantly the status of HD flies by increasing their lifespan, reducing their locomotor deficits and rescuing eye neurodegeneration. Then, we investigated whether increasing the major pathways of glucose catabolism, glycolysis and pentose-phosphate pathway (PPP) impacts HD. To mimic increased glycolytic flux, we overexpressed phosphofructokinase (PFK) which catalyzes an irreversible step in glycolysis. Overexpression of PFK did not affect HQ93 fly survival, but protected from photoreceptor loss. Overexpression of glucose-6-phosphate dehydrogenase (G6PD), the key enzyme of the PPP, extended significantly the lifespan of HD flies and rescued eye neurodegeneration. Since G6PD is able to synthesize NADPH involved in cell survival by maintenance of the redox state, we showed that tolerance to experimental oxidative stress was enhanced in flies co-expressing HQ93 and G6PD. Additionally overexpressions of hGluT3, G6PD or PFK were able to circumvent mitochondrial deficits induced by specific silencing of genes necessary for mitochondrial homeostasis. Our study confirms the involvement of bioenergetic deficits in HD course; they can be rescued by specific expression of a glucose transporter in neurons. Finally, the PPP and, to a lesser extent, the glycolysis seem to mediate the hGluT3 protective effects, whereas, in addition, the PPP provides increased protection to oxidative stress.
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Affiliation(s)
- Marie Thérèse Besson
- Aix-Marseille Université, CNRS, CRN2M-UMR7286, 13344 Marseille cedex 15, Marseille, France
| | - Karin Alegría
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, Chile
| | - Pamela Garrido-Gerter
- Centro de Estudios Científicos, Arturo Prat 514, Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | | | - Jean-Charles Liévens
- Aix-Marseille Université, CNRS, CRN2M-UMR7286, 13344 Marseille cedex 15, Marseille, France
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152
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Zhang S, Yang C, Yang Z, Zhang D, Ma X, Mills G, Liu Z. Homeostasis of redox status derived from glucose metabolic pathway could be the key to understanding the Warburg effect. Am J Cancer Res 2015; 5:928-944. [PMID: 26045978 PMCID: PMC4449427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/20/2015] [Indexed: 06/04/2023] Open
Abstract
Glucose metabolism in mitochondria through oxidative phosphorylation (OXPHOS) for generation of adenosine triphosphate (ATP) is vital for cell function. However, reactive oxygen species (ROS), a by-product from OXPHOS, is a major source of endogenously produced toxic stressors on the genome. In fact, ATP could be efficiently produced in a high throughput manner without ROS generation in cytosol through glycolysis, which could be a unique and critical metabolic pathway to prevent spontaneous mutation during DNA replication. Therefore glycolysis is dominant in robust proliferating cells. Indeed, aerobic glycolysis, or the Warburg effect, in normal proliferating cells is an example of homeostasis of redox status by transiently shifting metabolic flux from OXPHOS to glycolysis to avoid ROS generation during DNA synthesis and protect genome integrity. The process of maintaining redox homeostasis is driven by genome wide transcriptional clustering with mitochondrial retrograde signaling and coupled with the glucose metabolic pathway and cell division cycle. On the contrary, the Warburg effect in cancer cells is the results of the alteration of redox status from a reprogramed glucose metabolic pathway caused by the dysfunctional OXPHOS. Mutations in mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) disrupt mitochondrial structural integrity, leading to reduced OXPHOS capacity, sustained glycolysis and excessive ROS leak, all of which are responsible for tumor initiation, progression and metastasis. A "plumbing model" is used to illustrate how redox status could be regulated through glucose metabolic pathway and provide a new insight into the understanding of the Warburg effect in both normal and cancer cells.
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Affiliation(s)
- Shiwu Zhang
- Department of Pathology, Tianjin Union Medical CenterTianjin, People’s Republic of China
| | - Chuanwei Yang
- Department of Systems Biology, The University of Texas MD Anderson Cancer CenterHouston, TX, 77030, USA
- Breast Medical Oncology, The University of Texas MD Anderson Cancer CenterHouston, TX, 77030, USA
| | - Zhenduo Yang
- Department of Pathology, Tianjin Union Medical CenterTianjin, People’s Republic of China
| | - Dan Zhang
- Department of Pathology, Tianjin Union Medical CenterTianjin, People’s Republic of China
| | - Xiaoping Ma
- Department of Integrative Biology and Pharmacology, The University of Texas Medical SchoolHouston, TX 77030, USA
| | - Gordon Mills
- Department of Systems Biology, The University of Texas MD Anderson Cancer CenterHouston, TX, 77030, USA
| | - Zesheng Liu
- Department of Systems Biology, The University of Texas MD Anderson Cancer CenterHouston, TX, 77030, USA
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153
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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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154
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Iannetti EF, Willems PHGM, Pellegrini M, Beyrath J, Smeitink JAM, Blanchet L, Koopman WJH. Toward high-content screening of mitochondrial morphology and membrane potential in living cells. Int J Biochem Cell Biol 2015; 63:66-70. [PMID: 25668473 DOI: 10.1016/j.biocel.2015.01.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/14/2015] [Accepted: 01/29/2015] [Indexed: 11/20/2022]
Abstract
Mitochondria are double membrane organelles involved in various key cellular processes. Governed by dedicated protein machinery, mitochondria move and continuously fuse and divide. These "mitochondrial dynamics" are bi-directionally linked to mitochondrial and cell functional state in space and time. Due to the action of the electron transport chain (ETC), the mitochondrial inner membrane displays a inside-negative membrane potential (Δψ). The latter is considered a functional readout of mitochondrial "health" and required to sustain normal mitochondrial ATP production and mitochondrial fusion. During the last decade, live-cell microscopy strategies were developed for simultaneous quantification of Δψ and mitochondrial morphology. This revealed that ETC dysfunction, changes in Δψ and aberrations in mitochondrial structure often occur in parallel, suggesting they are linked potential targets for therapeutic intervention. Here we discuss how combining high-content and high-throughput strategies can be used for analysis of genetic and/or drug-induced effects at the level of individual organelles, cells and cell populations. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.
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Affiliation(s)
| | - Peter H G M Willems
- Khondrion BV, Nijmegen, The Netherlands; Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | - Jan A M Smeitink
- Khondrion BV, Nijmegen, The Netherlands; Department of Pediatrics, Nijmegen Center for Mitochondria disorders, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Werner J H Koopman
- Khondrion BV, Nijmegen, The Netherlands; Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
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155
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Mitochondrial diseases: Drosophila melanogaster as a model to evaluate potential therapeutics. Int J Biochem Cell Biol 2015; 63:60-5. [PMID: 25666557 DOI: 10.1016/j.biocel.2015.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/19/2015] [Accepted: 01/29/2015] [Indexed: 01/26/2023]
Abstract
While often presented as a single entity, mitochondrial diseases comprise a wide range of clinical, biochemical and genetic heterogeneous disorders. Among them, defects in the process of oxidative phosphorylation are the most prevalent. Despite intense research efforts, patients are still without effective treatment. An important part of the development of new therapeutics relies on predictive models of the pathology in order to assess their therapeutic potential. Since mitochondrial diseases are a heterogeneous group of progressive multisystemic disorders that can affect any organ at any time, the development of various in vivo models for the different diseases-associated genes defects will accelerate the search for effective therapeutics. Here, we review existing Drosophila melanogaster models for mitochondrial diseases, with a focus on alterations in oxidative phosphorylation, and discuss the potential of this powerful model organism in the process of drug target discovery. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.
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156
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Blanchet L, Smeitink JAM, van Emst-de Vries SE, Vogels C, Pellegrini M, Jonckheere AI, Rodenburg RJT, Buydens LMC, Beyrath J, Willems PHGM, Koopman WJH. Quantifying small molecule phenotypic effects using mitochondrial morpho-functional fingerprinting and machine learning. Sci Rep 2015; 5:8035. [PMID: 25620325 PMCID: PMC4306129 DOI: 10.1038/srep08035] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/22/2014] [Indexed: 12/31/2022] Open
Abstract
In primary fibroblasts from Leigh Syndrome (LS) patients, isolated mitochondrial complex I deficiency is associated with increased reactive oxygen species levels and mitochondrial morpho-functional changes. Empirical evidence suggests these aberrations constitute linked therapeutic targets for small chemical molecules. However, the latter generally induce multiple subtle effects, meaning that in vitro potency analysis or single-parameter high-throughput cell screening are of limited use to identify these molecules. We combine automated image quantification and artificial intelligence to discriminate between primary fibroblasts of a healthy individual and a LS patient based upon their mitochondrial morpho-functional phenotype. We then evaluate the effects of newly developed Trolox variants in LS patient cells. This revealed that Trolox ornithylamide hydrochloride best counterbalanced mitochondrial morpho-functional aberrations, effectively scavenged ROS and increased the maximal activity of mitochondrial complexes I, IV and citrate synthase. Our results suggest that Trolox-derived antioxidants are promising candidates in therapy development for human mitochondrial disorders.
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Affiliation(s)
- Lionel Blanchet
- 1] Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands [2] Analytical Chemistry/Chemometrics, Institute for Molecules and Materials, Radboud University, postvak 61P.O. Box 9010, 6500 GL Nijmegen, The Netherlands [3] Centre for Systems Biology and Bioenergetics, Radboud University Medical Center, Nijmegen, The Netherlands [4] Khondrion BV, Philips van Leydenlaan 15, 6525EX Nijmegen, The Netherlands
| | - Jan A M Smeitink
- 1] Centre for Systems Biology and Bioenergetics, Radboud University Medical Center, Nijmegen, The Netherlands [2] Khondrion BV, Philips van Leydenlaan 15, 6525EX Nijmegen, The Netherlands [3] Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Center, Nijmegen, Geert Grooteplein 10PO BOX 9101, 6500 HB Nijmegen, The Netherlands
| | - Sjenet E van Emst-de Vries
- 1] Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands [2] Khondrion BV, Philips van Leydenlaan 15, 6525EX Nijmegen, The Netherlands
| | - Caroline Vogels
- Khondrion BV, Philips van Leydenlaan 15, 6525EX Nijmegen, The Netherlands
| | - Mina Pellegrini
- Khondrion BV, Philips van Leydenlaan 15, 6525EX Nijmegen, The Netherlands
| | - An I Jonckheere
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Center, Nijmegen, Geert Grooteplein 10PO BOX 9101, 6500 HB Nijmegen, The Netherlands
| | - Richard J T Rodenburg
- 1] Centre for Systems Biology and Bioenergetics, Radboud University Medical Center, Nijmegen, The Netherlands [2] Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Center, Nijmegen, Geert Grooteplein 10PO BOX 9101, 6500 HB Nijmegen, The Netherlands
| | - Lutgarde M C Buydens
- 1] Analytical Chemistry/Chemometrics, Institute for Molecules and Materials, Radboud University, postvak 61P.O. Box 9010, 6500 GL Nijmegen, The Netherlands [2] Centre for Systems Biology and Bioenergetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Julien Beyrath
- Khondrion BV, Philips van Leydenlaan 15, 6525EX Nijmegen, The Netherlands
| | - Peter H G M Willems
- 1] Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands [2] Centre for Systems Biology and Bioenergetics, Radboud University Medical Center, Nijmegen, The Netherlands [3] Khondrion BV, Philips van Leydenlaan 15, 6525EX Nijmegen, The Netherlands
| | - Werner J H Koopman
- 1] Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands [2] Centre for Systems Biology and Bioenergetics, Radboud University Medical Center, Nijmegen, The Netherlands [3] Khondrion BV, Philips van Leydenlaan 15, 6525EX Nijmegen, The Netherlands
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157
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Baarine M, Beeson C, Singh A, Singh I. ABCD1 deletion-induced mitochondrial dysfunction is corrected by SAHA: implication for adrenoleukodystrophy. J Neurochem 2015; 133:380-96. [PMID: 25393703 DOI: 10.1111/jnc.12992] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/09/2014] [Accepted: 11/07/2014] [Indexed: 01/09/2023]
Abstract
X-linked Adrenoleukodystrophy (X-ALD), an inherited peroxisomal metabolic neurodegenerative disorder, is caused by mutations/deletions in the ATP-binding cassette transporter (ABCD1) gene encoding peroxisomal ABC transporter adrenoleukodystrophy protein (ALDP). Metabolic dysfunction in X-ALD is characterized by the accumulation of very long chain fatty acids ≥ C22:0) in the tissues and plasma of patients. Here, we investigated the mitochondrial status following deletion of ABCD1 in B12 oligodendrocytes and U87 astrocytes. This study provides evidence that silencing of peroxisomal protein ABCD1 produces structural and functional perturbations in mitochondria. Activities of electron transport chain-related enzymes and of citric acid cycle (TCA cycle) were reduced; mitochondrial redox status was dysregulated and the mitochondrial membrane potential was disrupted following ABCD1 silencing. A greater reduction in ATP levels and citrate synthase activities was observed in oligodendrocytes as compared to astrocytes. Furthermore, most of the mitochondrial perturbations induced by ABCD1 silencing were corrected by treating cells with suberoylanilide hydroxamic acid, an Histone deacetylase inhibitor. These observations indicate a novel relationship between peroxisomes and mitochondria in cellular homeostasis and the importance of intact peroxisomes in relation to mitochondrial integrity and function in the cell types that participate in the pathobiology of X-ALD. These observations suggest suberoylanilide hydroxamic acid as a potential therapy for X-ALD. Schematic description of the effects of loss of peroxisomal ATP-binding cassette transporter D1 (ABCD1) gene on cellular Redox and mitochondrial activities and their correction by suberoylanilide hydroxamic acid (SAHA) treatment. Pathogenomic accumulation of very long chain fatty acids (VLCFA) as a result of loss of ABCD1 leads to dysfunctions of mitochondrial biogenesis and its activities. Treatment with SAHA corrects mitochondrial dysfunctions. These studies describe unique cooperation between mitochondria and peroxisome for cellular activities.
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Affiliation(s)
- Mauhamad Baarine
- Department of Pediatrics, Darby Children's Research Institute, Medical University of South Carolina, Charleston, South Carolina, USA
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158
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Speijer D, Manjeri GR, Szklarczyk R. How to deal with oxygen radicals stemming from mitochondrial fatty acid oxidation. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130446. [PMID: 24864314 DOI: 10.1098/rstb.2013.0446] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Oxygen radical formation in mitochondria is an incompletely understood attribute of eukaryotic cells. Recently, a kinetic model was proposed, in which the ratio between electrons entering the respiratory chain via FADH2 or NADH determines radical formation. During glucose breakdown, the ratio is low; during fatty acid breakdown, the ratio is high (the ratio increasing--asymptotically--with fatty acid length to 0.5, when compared with 0.2 for glucose). Thus, fatty acid oxidation would generate higher levels of radical formation. As a result, breakdown of fatty acids, performed without generation of extra FADH2 in mitochondria, could be beneficial for the cell, especially in the case of long and very long chained ones. This possibly has been a major factor in the evolution of peroxisomes. Increased radical formation, as proposed by the model, can also shed light on the lack of neuronal fatty acid oxidation and tells us about hurdles during early eukaryotic evolution. We specifically focus on extending and discussing the model in light of recent publications and findings.
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Affiliation(s)
- D Speijer
- Department of Medical Biochemistry, Academic Medical Center (AMC), UvA, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - G R Manjeri
- Department of Biochemistry, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - R Szklarczyk
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands Department of Clinical Genetics, Unit Clinical Genomics, Maastricht University Medical Centre, 6200 MD Maastricht, The Netherlands
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159
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Szklarczyk R, Nooteboom M, Osiewacz HD. Control of mitochondrial integrity in ageing and disease. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130439. [PMID: 24864310 DOI: 10.1098/rstb.2013.0439] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Various molecular and cellular pathways are active in eukaryotes to control the quality and integrity of mitochondria. These pathways are involved in keeping a 'healthy' population of this essential organelle during the lifetime of the organism. Quality control (QC) systems counteract processes that lead to organellar dysfunction manifesting as degenerative diseases and ageing. We discuss disease- and ageing-related pathways involved in mitochondrial QC: mtDNA repair and reorganization, regeneration of oxidized amino acids, refolding and degradation of severely damaged proteins, degradation of whole mitochondria by mitophagy and finally programmed cell death. The control of the integrity of mtDNA and regulation of its expression is essential to remodel single proteins as well as mitochondrial complexes that determine mitochondrial functions. The redundancy of components, such as proteases, and the hierarchies of the QC raise questions about crosstalk between systems and their precise regulation. The understanding of the underlying mechanisms on the genomic, proteomic, organellar and cellular levels holds the key for the development of interventions for mitochondrial dysfunctions, degenerative processes, ageing and age-related diseases resulting from impairments of mitochondria.
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Affiliation(s)
- Radek Szklarczyk
- Centre for Molecular and Biomolecular Informatics, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands Department of Clinical Genetics, Unit Clinical Genomics, Maastricht University Medical Centre, 6200 MD Maastricht, The Netherlands
| | - Marco Nooteboom
- Department of Biochemistry (286), Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Heinz D Osiewacz
- Faculty for Biosciences and Cluster of Excellence 'Macromolecular Complexes', Goethe University, Molecular Developmental Biology, 60438 Frankfurt am Main, Germany
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160
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Strauss KA, Jinks RN, Puffenberger EG, Venkatesh S, Singh K, Cheng I, Mikita N, Thilagavathi J, Lee J, Sarafianos S, Benkert A, Koehler A, Zhu A, Trovillion V, McGlincy M, Morlet T, Deardorff M, Innes AM, Prasad C, Chudley AE, Lee INW, Suzuki CK. CODAS syndrome is associated with mutations of LONP1, encoding mitochondrial AAA+ Lon protease. Am J Hum Genet 2015; 96:121-35. [PMID: 25574826 DOI: 10.1016/j.ajhg.2014.12.003] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 12/05/2014] [Indexed: 12/30/2022] Open
Abstract
CODAS syndrome is a multi-system developmental disorder characterized by cerebral, ocular, dental, auricular, and skeletal anomalies. Using whole-exome and Sanger sequencing, we identified four LONP1 mutations inherited as homozygous or compound-heterozygous combinations among ten individuals with CODAS syndrome. The individuals come from three different ancestral backgrounds (Amish-Swiss from United States, n = 8; Mennonite-German from Canada, n = 1; mixed European from Canada, n = 1). LONP1 encodes Lon protease, a homohexameric enzyme that mediates protein quality control, respiratory-complex assembly, gene expression, and stress responses in mitochondria. All four pathogenic amino acid substitutions cluster within the AAA(+) domain at residues near the ATP-binding pocket. In biochemical assays, pathogenic Lon proteins show substrate-specific defects in ATP-dependent proteolysis. When expressed recombinantly in cells, all altered Lon proteins localize to mitochondria. The Old Order Amish Lon variant (LONP1 c.2161C>G[p.Arg721Gly]) homo-oligomerizes poorly in vitro. Lymphoblastoid cell lines generated from affected children have (1) swollen mitochondria with electron-dense inclusions and abnormal inner-membrane morphology; (2) aggregated MT-CO2, the mtDNA-encoded subunit II of cytochrome c oxidase; and (3) reduced spare respiratory capacity, leading to impaired mitochondrial proteostasis and function. CODAS syndrome is a distinct, autosomal-recessive, developmental disorder associated with dysfunction of the mitochondrial Lon protease.
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Affiliation(s)
- Kevin A Strauss
- Clinic for Special Children, Strasburg, PA 17579, USA; Lancaster General Hospital, Lancaster, PA 17602, USA; Department of Biology and Biological Foundations of Behavior Program, Franklin and Marshall College, Lancaster, PA 17603, USA.
| | - Robert N Jinks
- Department of Biology and Biological Foundations of Behavior Program, Franklin and Marshall College, Lancaster, PA 17603, USA
| | - Erik G Puffenberger
- Clinic for Special Children, Strasburg, PA 17579, USA; Department of Biology and Biological Foundations of Behavior Program, Franklin and Marshall College, Lancaster, PA 17603, USA
| | - Sundararajan Venkatesh
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Kamalendra Singh
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA; Department of Molecular Microbiology and Immunology, Christopher Bond Life Sciences Center, University of Missouri, Columbia, Columbia, MO 65201, USA
| | - Iteen Cheng
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Natalie Mikita
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jayapalraja Thilagavathi
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Jae Lee
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Stefan Sarafianos
- Department of Molecular Microbiology and Immunology, Christopher Bond Life Sciences Center, University of Missouri, Columbia, Columbia, MO 65201, USA
| | - Abigail Benkert
- Clinic for Special Children, Strasburg, PA 17579, USA; Department of Biology and Biological Foundations of Behavior Program, Franklin and Marshall College, Lancaster, PA 17603, USA
| | - Alanna Koehler
- Department of Biology and Biological Foundations of Behavior Program, Franklin and Marshall College, Lancaster, PA 17603, USA
| | - Anni Zhu
- Department of Biology and Biological Foundations of Behavior Program, Franklin and Marshall College, Lancaster, PA 17603, USA
| | - Victoria Trovillion
- Department of Biology and Biological Foundations of Behavior Program, Franklin and Marshall College, Lancaster, PA 17603, USA
| | - Madeleine McGlincy
- Department of Biology and Biological Foundations of Behavior Program, Franklin and Marshall College, Lancaster, PA 17603, USA
| | - Thierry Morlet
- Auditory Physiology and Psychoacoustics Research Laboratory, duPont Hospital for Children, Wilmington, DE 19803, USA
| | - Matthew Deardorff
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - A Micheil Innes
- Department of Medical Genetics and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Chitra Prasad
- Medical Genetics Program, Department of Pediatrics, Children's Health Research Institute and Western University, London, ON N6C 2V5, Canada
| | - Albert E Chudley
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB R3A 1S1, Canada; Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB R3A 1S1, Canada
| | - Irene Nga Wing Lee
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Carolyn K Suzuki
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
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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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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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164
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Sandoval H, Yao CK, Chen K, Jaiswal M, Donti T, Lin YQ, Bayat V, Xiong B, Zhang K, David G, Charng WL, Yamamoto S, Duraine L, Graham BH, Bellen HJ. Mitochondrial fusion but not fission regulates larval growth and synaptic development through steroid hormone production. eLife 2014; 3. [PMID: 25313867 PMCID: PMC4215535 DOI: 10.7554/elife.03558] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 10/13/2014] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial fusion and fission affect the distribution and quality control of mitochondria. We show that Marf (Mitochondrial associated regulatory factor), is required for mitochondrial fusion and transport in long axons. Moreover, loss of Marf leads to a severe depletion of mitochondria in neuromuscular junctions (NMJs). Marf mutants also fail to maintain proper synaptic transmission at NMJs upon repetitive stimulation, similar to Drp1 fission mutants. However, unlike Drp1, loss of Marf leads to NMJ morphology defects and extended larval lifespan. Marf is required to form contacts between the endoplasmic reticulum and/or lipid droplets (LDs) and for proper storage of cholesterol and ecdysone synthesis in ring glands. Interestingly, human Mitofusin-2 rescues the loss of LD but both Mitofusin-1 and Mitofusin-2 are required for steroid-hormone synthesis. Our data show that Marf and Mitofusins share an evolutionarily conserved role in mitochondrial transport, cholesterol ester storage and steroid-hormone synthesis. DOI:http://dx.doi.org/10.7554/eLife.03558.001 Mitochondria are the main source of energy for cells. These vital and highly dynamic organelles continually change shape by fusing with each other and splitting apart to create new mitochondria, repairing and replacing those damaged by cell stress. For nerve impulses to be transmitted across the gaps (called synapses) between nerve cells, mitochondria need to supply the very ends of the nerve fibers with energy. To do this, the mitochondria must be transported from the main body of the nerve cell to the tips of the nerve fibers. This may not happen if mitochondria are the wrong shape, size or damaged. While searching for genetic mutations that disrupt nerve function in the fruit fly Drosophila, Sandoval et al. spotted mutations in a gene called Marf. Further investigations revealed that flies with mutant versions of Marf have small, round mitochondria, and their nerves cannot transmit signals to muscles when they are highly stimulated. This is because the mutant mitochondria are not easily transported along nerve fibers, and so not enough energy is supplied to the synapses. The synapses of the Marf mutants are also abnormally shaped. Sandoval et al. found that this is not because Marf is lost in the neurons themselves, but because it is lost from a hormone-producing tissue called the ring gland. Another problem found in flies with mutated Marf genes is that they stop developing while in their larval stage. Sandoval et al. established that this could also be related to the loss of Marf from the ring gland. The Marf protein has two different functions in the ring gland: forming and storing droplets of fatty molecules used in hormone production, and synthesising a hormone that controls when a fly larva matures into the adult fly. This suggests that the lower levels of this hormone produced by Marf mutant flies underlies their prolonged larval stages and synapse defects. Vertebrates (animals with backbones, such as humans) have two genes that are related to the fly's Marf gene. When the human forms of these genes were introduced into mutant flies that lack a working copy of Marf, hormone production was only restored if both genes were introduced together. This indicates that these genes have separate roles in vertebrates, but that these roles are both performed by the single fly gene. The role of Marf in tethering mitochondria in the ring gland may allow us to better understand how this process affects hormone production and how the different parts of the cell communicate. DOI:http://dx.doi.org/10.7554/eLife.03558.002
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Affiliation(s)
- Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Chi-Kuang Yao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Taraka Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Yong Qi Lin
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Vafa Bayat
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, United States
| | - Gabriela David
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Wu-Lin Charng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
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165
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Yadav N, Pliss A, Kuzmin A, Rapali P, Sun L, Prasad P, Chandra D. Transformations of the macromolecular landscape at mitochondria during DNA-damage-induced apoptotic cell death. Cell Death Dis 2014; 5:e1453. [PMID: 25299778 PMCID: PMC4649512 DOI: 10.1038/cddis.2014.405] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/08/2014] [Accepted: 08/14/2014] [Indexed: 12/18/2022]
Abstract
Apoptosis is a dynamic process regulated by mitochondrion critical for cellular respiration and survival. Execution of apoptosis is mediated by multiple protein signaling events at mitochondria. Initiation and progression of apoptosis require numerous apoptogenic factors that are either released from or sequestered in mitochondria, which may transform the biomolecular makeup of the organelle. In this communication, using Raman microspectroscopy, we demonstrate that transformation in biomolecular composition of mitochondrion may be used as apoptosis marker in an individual cell. For the first time, we show that significant changes occur in the concentrations of RNA, DNA, protein, and lipid constituents of mitochondria during apoptosis. The structural analysis of proteins on mitochondria demonstrated a decrease in α-helix secondary structure content, and an increase in the levels of random coils and β-sheets on mitochondria. This may represent an additional hallmark of apoptosis. Strikingly, we observed nearly identical changes in macromolecular content of mitochondria both in the presence and absence of a key proapoptotic protein, Bax (Bcl-2-associated X protein). Increased DNA level in mitochondria corresponded with higher mitochondrial DNA (mtDNA), cellular reactive oxygen species (ROS), and mitochondrial ROS production. Upregulation of polymerase-γ (POLG), mitochondrial helicase Twinkle, and mitochondrial transcription factor A (Tfam) in response to DNA damage correlated with increased mtDNA and RNA synthesis. Elevated activity of oxidative phosphorylation complexes supports functional mitochondrial respiration during apoptosis. Thus, we define previously unknown dynamic correlation of macromolecular structure of mitochondria and apoptosis progression in the presence and absence of Bax protein. These findings open up a new approach for monitoring physiological status of cells by non invasive single-cell method.
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Affiliation(s)
- N Yadav
- Department of Pharmacology and Therapeutics, Center for Genetics and Pharmacology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY, USA
| | - A Pliss
- Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - A Kuzmin
- Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - P Rapali
- Department of Pharmacology and Therapeutics, Center for Genetics and Pharmacology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY, USA
| | - L Sun
- 1] Department of Pharmacology and Therapeutics, Center for Genetics and Pharmacology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY, USA [2] Gastrointestinal Division, Sir Run Run Shaw Hospital, Zhejiang University Medical School, Hangzhou, China
| | - P Prasad
- Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - D Chandra
- Department of Pharmacology and Therapeutics, Center for Genetics and Pharmacology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY, USA
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166
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Hofer A, Wenz T. Post-translational modification of mitochondria as a novel mode of regulation. Exp Gerontol 2014; 56:202-20. [DOI: 10.1016/j.exger.2014.03.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/01/2014] [Accepted: 03/04/2014] [Indexed: 12/26/2022]
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167
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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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168
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Wu YT, Wu SB, Wei YH. Roles of sirtuins in the regulation of antioxidant defense and bioenergetic function of mitochondria under oxidative stress. Free Radic Res 2014; 48:1070-84. [DOI: 10.3109/10715762.2014.920956] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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169
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Grand RS, Martienssen R, O'Sullivan JM. Potential roles for interactions between the mitochondrial and nuclear DNA throughout the cell cycle of Schizosaccharomyces pombe. Mitochondrion 2014; 17:141-9. [PMID: 24815909 PMCID: PMC4209164 DOI: 10.1016/j.mito.2014.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/28/2014] [Accepted: 04/30/2014] [Indexed: 11/29/2022]
Abstract
Over the course of mitochondrial evolution, the majority of genes required for its function have been transferred and integrated into nuclear chromosomes. Ongoing transfer of mitochondrial DNA to the nucleus has been detected, but its functional significance has not been fully elucidated. Here by Genome Conformation Capture, we identify DNA-DNA interactions between the mitochondrial and nuclear chromosomes (mt-nDNA interactions) that vary in strength and number between the G1, G2 and M phases of the fission yeast cell cycle. Mt-nDNA interactions captured in mitotic anaphase were associated with nuclear genes required for the regulation of cell growth and energy availability. Furthermore, mt-nDNA interactions captured in the G1 phase involved high efficiency, early firing origins of DNA replication. Collectively, these results suggest functional roles for the ongoing transfer of regions of the mitochondrial genome to the nucleus.
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Affiliation(s)
- R S Grand
- Liggins institute, University of Auckland, Grafton, Auckland 1032, New Zealand; Institute of Natural and Mathematical Sciences, Massey University, Albany, Auckland 0745, New Zealand
| | - R Martienssen
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - J M O'Sullivan
- Liggins institute, University of Auckland, Grafton, Auckland 1032, New Zealand
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170
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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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171
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Mitochondrial hyperpolarization during chronic complex I inhibition is sustained by low activity of complex II, III, IV and V. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1247-56. [PMID: 24769419 DOI: 10.1016/j.bbabio.2014.04.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 04/11/2014] [Accepted: 04/18/2014] [Indexed: 02/01/2023]
Abstract
The mitochondrial oxidative phosphorylation (OXPHOS) system consists of four electron transport chain (ETC) complexes (CI-CIV) and the FoF1-ATP synthase (CV), which sustain ATP generation via chemiosmotic coupling. The latter requires an inward-directed proton-motive force (PMF) across the mitochondrial inner membrane (MIM) consisting of a proton (ΔpH) and electrical charge (Δψ) gradient. CI actively participates in sustaining these gradients via trans-MIM proton pumping. Enigmatically, at the cellular level genetic or inhibitor-induced CI dysfunction has been associated with Δψ depolarization or hyperpolarization. The cellular mechanism of the latter is still incompletely understood. Here we demonstrate that chronic (24h) CI inhibition in HEK293 cells induces a proton-based Δψ hyperpolarization in HEK293 cells without triggering reverse-mode action of CV or the adenine nucleotide translocase (ANT). Hyperpolarization was associated with low levels of CII-driven O2 consumption and prevented by co-inhibition of CII, CIII or CIV activity. In contrast, chronic CIII inhibition triggered CV reverse-mode action and induced Δψ depolarization. CI- and CIII-inhibition similarly reduced free matrix ATP levels and increased the cell's dependence on extracellular glucose to maintain cytosolic free ATP. Our findings support a model in which Δψ hyperpolarization in CI-inhibited cells results from low activity of CII, CIII and CIV, combined with reduced forward action of CV and ANT.
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172
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van Rahden VA, Rau I, Fuchs S, Kosyna FK, de Almeida HL, Fryssira H, Isidor B, Jauch A, Joubert M, Lachmeijer AMA, Zweier C, Moog U, Kutsche K. Clinical spectrum of females with HCCS mutation: from no clinical signs to a neonatal lethal form of the microphthalmia with linear skin defects (MLS) syndrome. Orphanet J Rare Dis 2014; 9:53. [PMID: 24735900 PMCID: PMC4021606 DOI: 10.1186/1750-1172-9-53] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/11/2014] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Segmental Xp22.2 monosomy or a heterozygous HCCS mutation is associated with the microphthalmia with linear skin defects (MLS) or MIDAS (microphthalmia, dermal aplasia, and sclerocornea) syndrome, an X-linked disorder with male lethality. HCCS encodes the holocytochrome c-type synthase involved in mitochondrial oxidative phosphorylation (OXPHOS) and programmed cell death. METHODS We characterized the X-chromosomal abnormality encompassing HCCS or an intragenic mutation in this gene in six new female patients with an MLS phenotype by cytogenetic analysis, fluorescence in situ hybridization, sequencing, and quantitative real-time PCR. The X chromosome inactivation (XCI) pattern was determined and clinical data of the patients were reviewed. RESULTS Two terminal Xp deletions of ≥ 11.2 Mb, two submicroscopic copy number losses, one of ~850 kb and one of ≥ 3 Mb, all covering HCCS, 1 nonsense, and one mosaic 2-bp deletion in HCCS are reported. All females had a completely (>98:2) or slightly skewed (82:18) XCI pattern. The most consistent clinical features were microphthalmia/anophthalmia and sclerocornea/corneal opacity in all patients and congenital linear skin defects in 4/6. Additional manifestations included various ocular anomalies, cardiac defects, brain imaging abnormalities, microcephaly, postnatal growth retardation, and facial dysmorphism. However, no obvious clinical sign was observed in three female carriers who were relatives of one patient. CONCLUSION Our findings showed a wide phenotypic spectrum ranging from asymptomatic females with an HCCS mutation to patients with a neonatal lethal MLS form. Somatic mosaicism and the different ability of embryonic cells to cope with an OXPHOS defect and/or enhanced cell death upon HCCS deficiency likely underlie the great variability in phenotypes.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany.
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173
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Nishimura N, Gotoh T, Oike Y, Yano M. TMEM65 is a mitochondrial inner-membrane protein. PeerJ 2014; 2:e349. [PMID: 24765583 PMCID: PMC3994636 DOI: 10.7717/peerj.349] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 03/26/2014] [Indexed: 12/16/2022] Open
Abstract
It has been reported that the expression of TMEM65 is regulated by steroid receptor RNA activator (SRA). To date, however, the localization and function of TMEM65 remained unknown. We analyzed the intracellular localization of TMEM65. Immunoblot and immunostaining analysis revealed mitochondrial localization of TMEM65. Alkali extraction analysis and digitonin extraction test using isolated mitochondria revealed that TMEM65 is an integral membrane protein that localizes to the inner-membrane of mitochondria. Analysis using deletion mutants of TMEM65 suggested that the N-terminal region (1–20) of this protein is sufficient for mitochondrial targeting and that this mitochondrial targeting signal (MTS) is cleaved between the amino acid positions 35 and 64, which contain a putative recognition site of matrix processing protease (MPP). Together, these results suggest that TMEM65 is imported into the mitochondria, integrated into mitochondrial inner-membrane, and processed into its mature form by an MPP.
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Affiliation(s)
- Naotaka Nishimura
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University , Kumamoto , Japan
| | - Tomomi Gotoh
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University , Kumamoto , Japan ; Department of School Health, Faculty of Education, Kumamoto University , Kumamoto , Japan
| | - Yuichi Oike
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University , Kumamoto , Japan
| | - Masato Yano
- Department of Medical Technology, Faculty of Health Sciences, Kumamoto Health Science University , Kumamoto , Japan
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174
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Impaired mitochondrial respiration promotes dendritic branching via the AMPK signaling pathway. Cell Death Dis 2014; 5:e1175. [PMID: 24722300 PMCID: PMC5424120 DOI: 10.1038/cddis.2014.144] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 02/27/2014] [Indexed: 12/28/2022]
Abstract
Functional neuronal circuits require a constant remodeling of their network composed of highly interconnected neurons. The plasticity of synapses and the shaping of elaborated dendritic branches are energy demanding and therefore depend on an efficient mitochondrial oxidative phosphorylation (OXPHOS). The spatial and functional regulations of dendritic patterning occur also after cell fate specification; however, the molecular mechanisms underlying this complex process remain elusive. Here, we exploit the changes in dendritic architecture in highly branched neurons as a result of aberrant mitochondrial activity. In sensory neurons of Caenorhabditis elegans, genetic manipulations of mitochondrial complex I subunits cause an unexpected outgrowth of dendritic arbors and ectopic structures. The increased number of dendritic branches is coordinated through a specific signaling cascade rather than as a simple consequence of oxidative stress. On the basis of genetic and pharmacological evidence, we show that OXPHOS deficiency promotes branching through the activation of the AMP-activated protein kinase AMPK and the downstream target phosphoinositide 3-kinase PI3K. Taken together, our findings describe a well-defined signaling pathway that regulates dendritic outgrowth in conditions of compromised OXPHOS and the resulting AMPK activation.
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175
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Blake R, Trounce IA. Mitochondrial dysfunction and complications associated with diabetes. Biochim Biophys Acta Gen Subj 2014; 1840:1404-12. [DOI: 10.1016/j.bbagen.2013.11.007] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 10/18/2013] [Accepted: 11/06/2013] [Indexed: 02/06/2023]
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176
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Disruption of oxidative phosphorylation and synaptic Na(+), K(+)-ATPase activity by pristanic acid in cerebellum of young rats. Life Sci 2014; 94:67-73. [PMID: 24211616 DOI: 10.1016/j.lfs.2013.10.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/04/2013] [Accepted: 10/28/2013] [Indexed: 11/24/2022]
Abstract
AIMS Peroxisomal biogenesis disorders (PBD) are inherited disorders clinically manifested by neurological symptoms and brain abnormalities, in which the cerebellum is usually involved. Biochemically, patients affected by these neurodegenerative diseases accumulate branched-chain fatty acids, including pristanic acid (Prist) in the brain and other tissues. MAIN METHODS In the present investigation we studied the in vitro influence of Prist, at doses found in PBD, on oxidative phosphorylation, by measuring the activities of the respiratory chain complexes I-IV and ATP production, as well as on creatine kinase and synaptic Na(+), K(+)-ATPase activities in rat cerebellum. KEY FINDINGS Prist significantly decreased complexes I-III (65%), II (40%) and especially II-III (90%) activities, without altering the activities of complex IV of the respiratory chain and creatine kinase. Furthermore, ATP formation and synaptic Na(+), K(+)-ATPase activity were markedly inhibited (80-90%) by Prist. We also observed that this fatty acid altered mitochondrial and synaptic membrane fluidity that may have contributed to its inhibitory effects on the activities of the respiratory chain complexes and Na(+), K(+)-ATPase. SIGNIFICANCE Considering the importance of oxidative phosphorylation for mitochondrial homeostasis and of Na(+), K(+)-ATPase for the maintenance of cell membrane potential, the present data indicate that Prist compromises brain bioenergetics and neurotransmission in cerebellum. We postulate that these pathomechanisms may contribute to the cerebellar alterations observed in patients affected by PBD in which Prist is accumulated.
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177
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Gray LR, Tompkins SC, Taylor EB. Regulation of pyruvate metabolism and human disease. Cell Mol Life Sci 2013; 71:2577-604. [PMID: 24363178 PMCID: PMC4059968 DOI: 10.1007/s00018-013-1539-2] [Citation(s) in RCA: 522] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 11/24/2013] [Accepted: 12/02/2013] [Indexed: 12/31/2022]
Abstract
Pyruvate is a keystone molecule critical for numerous aspects of eukaryotic and human metabolism. Pyruvate is the end-product of glycolysis, is derived from additional sources in the cellular cytoplasm, and is ultimately destined for transport into mitochondria as a master fuel input undergirding citric acid cycle carbon flux. In mitochondria, pyruvate drives ATP production by oxidative phosphorylation and multiple biosynthetic pathways intersecting the citric acid cycle. Mitochondrial pyruvate metabolism is regulated by many enzymes, including the recently discovered mitochondria pyruvate carrier, pyruvate dehydrogenase, and pyruvate carboxylase, to modulate overall pyruvate carbon flux. Mutations in any of the genes encoding for proteins regulating pyruvate metabolism may lead to disease. Numerous cases have been described. Aberrant pyruvate metabolism plays an especially prominent role in cancer, heart failure, and neurodegeneration. Because most major diseases involve aberrant metabolism, understanding and exploiting pyruvate carbon flux may yield novel treatments that enhance human health.
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Affiliation(s)
- Lawrence R Gray
- Department of Biochemistry, Fraternal Order of the Eagles Diabetes Research Center, and François M. Abboud Cardiovascular Research Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 51 Newton Rd, 4-403 BSB, Iowa City, IA, 52242, USA
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178
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Abstract
Mitochondrial dysfunction has been associated with various diseases, such as cancer, myopathies, neurodegeneration and obesity. Mitochondrial homoeostasis is achieved by mechanisms that adapt the number of mitochondria to that required for energy production and for the supply of metabolic intermediates necessary to sustain cell growth. Simultaneously, mitochondrial quality control mechanisms are in place to remove malfunctioning mitochondria. In the cytoplasm, the protein complex mTORC1 couples growth-promoting signals with anabolic processes, in which mitochondria play an essential role. Here, we review the involvement of mTORC1 and Rheb in mitochondrial homoeostasis. The regulatory processes downstream of mTORC1 affect the glycolytic flux and the rate of mitophagy, and include regulation of the transcription factors HIF1α and YY1/PGC-1α. We also discuss how mitochondrial function feeds back on mTORC1 via reactive oxygen species signalling to adapt metabolic processes, and highlight how mTORC1 signalling is integrated with the unfolded protein response in mitochondria, which in Caenorhabditis elegans is mediated via transcription factors such as DVE-1/UBL-5 and ATFS-1.
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Affiliation(s)
- Marlous J Groenewoud
- Molecular Cancer Research, Centre for Biomedical Genetics and Cancer Genomics Centre, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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179
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de Oliveira GP, Alves CJ, Chadi G. Early gene expression changes in spinal cord from SOD1(G93A) Amyotrophic Lateral Sclerosis animal model. Front Cell Neurosci 2013; 7:216. [PMID: 24302897 PMCID: PMC3831149 DOI: 10.3389/fncel.2013.00216] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 10/29/2013] [Indexed: 11/13/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is an adult-onset and fast progression neurodegenerative disease that leads to the loss of motor neurons. Mechanisms of selective motor neuron loss in ALS are unknown. The early events occurring in the spinal cord that may contribute to motor neuron death are not described, neither astrocytes participation in the pre-symptomatic phases of the disease. In order to identify ALS early events, we performed a microarray analysis employing a whole mouse genome platform to evaluate the gene expression pattern of lumbar spinal cords of transgenic SOD1G93A mice and their littermate controls at pre-symptomatic ages of 40 and 80 days. Differentially expressed genes were identified by means of the Bioconductor packages Agi4×44Preprocess and limma. FunNet web based tool was used for analysis of over-represented pathways. Furthermore, immunolabeled astrocytes from 40 and 80 days old mice were submitted to laser microdissection and RNA was extracted for evaluation of a selected gene by qPCR. Statistical analysis has pointed to 492 differentially expressed genes (155 up and 337 down regulated) in 40 days and 1105 (433 up and 672 down) in 80 days old ALS mice. KEGG analysis demonstrated the over-represented pathways tight junction, antigen processing and presentation, oxidative phosphorylation, endocytosis, chemokine signaling pathway, ubiquitin mediated proteolysis and glutamatergic synapse at both pre-symptomatic ages. Ube2i gene expression was evaluated in astrocytes from both transgenic ages, being up regulated in 40 and 80 days astrocytes enriched samples. Our data points to important early molecular events occurring in pre-symptomatic phases of ALS in mouse model. Early SUMOylation process linked to astrocytes might account to non-autonomous cell toxicity in ALS. Further studies on the signaling pathways presented here may provide new insights to better understand the events triggering motor neuron death in this devastating disorder.
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Affiliation(s)
- Gabriela P de Oliveira
- Department of Neurology, Neuroregeneration Center, University of São Paulo School of Medicine São Paulo, Brazil
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180
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Kotiadis VN, Duchen MR, Osellame LD. Mitochondrial quality control and communications with the nucleus are important in maintaining mitochondrial function and cell health. Biochim Biophys Acta Gen Subj 2013; 1840:1254-65. [PMID: 24211250 PMCID: PMC3970188 DOI: 10.1016/j.bbagen.2013.10.041] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/14/2013] [Accepted: 10/29/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND The maintenance of cell metabolism and homeostasis is a fundamental characteristic of living organisms. In eukaryotes, mitochondria are the cornerstone of these life supporting processes, playing leading roles in a host of core cellular functions, including energy transduction, metabolic and calcium signalling, and supporting roles in a number of biosynthetic pathways. The possession of a discrete mitochondrial genome dictates that the maintenance of mitochondrial 'fitness' requires quality control mechanisms which involve close communication with the nucleus. SCOPE OF REVIEW This review explores the synergistic mechanisms that control mitochondrial quality and function and ensure cellular bioenergetic homeostasis. These include antioxidant defence mechanisms that protect against oxidative damage caused by reactive oxygen species, while regulating signals transduced through such free radicals. Protein homeostasis controls import, folding, and degradation of proteins underpinned by mechanisms that regulate bioenergetic capacity through the mitochondrial unfolded protein response. Autophagic machinery is recruited for mitochondrial turnover through the process of mitophagy. Mitochondria also communicate with the nucleus to exact specific transcriptional responses through retrograde signalling pathways. MAJOR CONCLUSIONS The outcome of mitochondrial quality control is not only reliant on the efficient operation of the core homeostatic mechanisms but also in the effective interaction of mitochondria with other cellular components, namely the nucleus. GENERAL SIGNIFICANCE Understanding mitochondrial quality control and the interactions between the organelle and the nucleus will be crucial in developing therapies for the plethora of diseases in which the pathophysiology is determined by mitochondrial dysfunction. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Vassilios N Kotiadis
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK; UCL Consortium for Mitochondrial Research, University College London, WC1E 6BT, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK; UCL Consortium for Mitochondrial Research, University College London, WC1E 6BT, UK
| | - Laura D Osellame
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK; UCL Consortium for Mitochondrial Research, University College London, WC1E 6BT, UK.
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181
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Wu SB, Wu YT, Wu TP, Wei YH. Role of AMPK-mediated adaptive responses in human cells with mitochondrial dysfunction to oxidative stress. Biochim Biophys Acta Gen Subj 2013; 1840:1331-44. [PMID: 24513455 DOI: 10.1016/j.bbagen.2013.10.034] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 10/06/2013] [Accepted: 10/22/2013] [Indexed: 02/09/2023]
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) mutations are an important cause of mitochondrial diseases, for which there is no effective treatment due to complex pathophysiology. It has been suggested that mitochondrial dysfunction-elicited reactive oxygen species (ROS) plays a vital role in the pathogenesis of mitochondrial diseases, and the expression levels of several clusters of genes are altered in response to the elevated oxidative stress. Recently, we reported that glycolysis in affected cells with mitochondrial dysfunction is upregulated by AMP-activated protein kinase (AMPK), and such an adaptive response of metabolic reprogramming plays an important role in the pathophysiology of mitochondrial diseases. SCOPE OF REVIEW We summarize recent findings regarding the role of AMPK-mediated signaling pathways that are involved in: (1) metabolic reprogramming, (2) alteration of cellular redox status and antioxidant enzyme expression, (3) mitochondrial biogenesis, and (4) autophagy, a master regulator of mitochondrial quality control in skin fibroblasts from patients with mitochondrial diseases. MAJOR CONCLUSION Induction of adaptive responses via AMPK-PFK2, AMPK-FOXO3a, AMPK-PGC-1α, and AMPK-mTOR signaling pathways, respectively is modulated for the survival of human cells under oxidative stress induced by mitochondrial dysfunction. We suggest that AMPK may be a potential target for the development of therapeutic agents for the treatment of mitochondrial diseases. GENERAL SIGNIFICANCE Elucidation of the adaptive mechanism involved in AMPK activation cascades would lead us to gain a deeper insight into the crosstalk between mitochondria and the nucleus in affected tissue cells from patients with mitochondrial diseases. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Shi-Bei Wu
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan
| | - Yu-Ting Wu
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan
| | - Tsung-Pu Wu
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan
| | - Yau-Huei Wei
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan; Department of Medicine, Mackay Medical College, New Taipei City 252, Taiwan.
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182
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Annesley SJ, Chen S, Francione LM, Sanislav O, Chavan AJ, Farah C, De Piazza SW, Storey CL, Ilievska J, Fernando SG, Smith PK, Lay ST, Fisher PR. Dictyostelium, a microbial model for brain disease. Biochim Biophys Acta Gen Subj 2013; 1840:1413-32. [PMID: 24161926 DOI: 10.1016/j.bbagen.2013.10.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 10/05/2013] [Accepted: 10/10/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND Most neurodegenerative diseases are associated with mitochondrial dysfunction. In humans, mutations in mitochondrial genes result in a range of phenotypic outcomes which do not correlate well with the underlying genetic cause. Other neurodegenerative diseases are caused by mutations that affect the function and trafficking of lysosomes, endosomes and autophagosomes. Many of the complexities of these human diseases can be avoided by studying them in the simple eukaryotic model Dictyostelium discoideum. SCOPE OF REVIEW This review describes research using Dictyostelium to study cytopathological pathways underlying a variety of neurodegenerative diseases including mitochondrial, lysosomal and vesicle trafficking disorders. MAJOR CONCLUSIONS Generalised mitochondrial respiratory deficiencies in Dictyostelium produce a consistent pattern of defective phenotypes that are caused by chronic activation of a cellular energy sensor AMPK (AMP-activated protein kinase) and not ATP deficiency per se. Surprisingly, when individual subunits of Complex I are knocked out, both AMPK-dependent and AMPK-independent, subunit-specific phenotypes are observed. Many nonmitochondrial proteins associated with neurological disorders have homologues in Dictyostelium and are associated with the function and trafficking of lysosomes and endosomes. Conversely, some genes associated with neurodegenerative disorders do not have homologues in Dictyostelium and this provides a unique avenue for studying these mutated proteins in the absence of endogeneous protein. GENERAL SIGNIFICANCE Using the Dictyostelium model we have gained insights into the sublethal cytopathological pathways whose dysregulation contributes to phenotypic outcomes in neurodegenerative disease. This work is beginning to distinguish correlation, cause and effect in the complex network of cross talk between the various organelles involved. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- S J Annesley
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - S Chen
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - L M Francione
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - O Sanislav
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - A J Chavan
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - C Farah
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - S W De Piazza
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - C L Storey
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - J Ilievska
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - S G Fernando
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - P K Smith
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - S T Lay
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086
| | - P R Fisher
- Department of Microbiology, La Trobe University, Plenty Rd., Bundoora, VIC, Australia, 3086.
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183
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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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184
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Mitochondrial DNA mutations and breast tumorigenesis. Biochim Biophys Acta Rev Cancer 2013; 1836:336-44. [PMID: 24140413 DOI: 10.1016/j.bbcan.2013.10.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 10/02/2013] [Accepted: 10/05/2013] [Indexed: 12/15/2022]
Abstract
Breast cancer is a heterogeneous disease and genetic factors play an important role in its genesis. Although mutations in tumor suppressors and oncogenes encoded by the nuclear genome are known to play a critical role in breast tumorigenesis, the contribution of the mitochondrial genome to this process is unclear. Like the nuclear genome, the mitochondrial genome also encodes proteins critical for mitochondrion functions such as oxidative phosphorylation (OXPHOS), which is known to be defective in cancer including breast cancer. Mitochondrial DNA (mtDNA) is more susceptible to mutations due to limited repair mechanisms compared to nuclear DNA (nDNA). Thus changes in mitochondrial genes could also contribute to the development of breast cancer. In this review we discuss mtDNA mutations that affect OXPHOS. Continuous acquisition of mtDNA mutations and selection of advantageous mutations ultimately leads to generation of cells that propagate uncontrollably to form tumors. Since irreversible damage to OXPHOS leads to a shift in energy metabolism towards enhanced aerobic glycolysis in most cancers, mutations in mtDNA represent an early event during breast tumorigenesis, and thus may serve as potential biomarkers for early detection and prognosis of breast cancer. Because mtDNA mutations lead to defective OXPHOS, development of agents that target OXPHOS will provide specificity for preventative and therapeutic agents against breast cancer with minimal toxicity.
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185
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Delmiro A, Rivera H, García-Silva MT, García-Consuegra I, Martín-Hernández E, Quijada-Fraile P, de Las Heras RS, Moreno-Izquierdo A, Martín MÁ, Arenas J, Martínez-Azorín F. Whole-exome sequencing identifies a variant of the mitochondrial MT-ND1 gene associated with epileptic encephalopathy: west syndrome evolving to Lennox-Gastaut syndrome. Hum Mutat 2013; 34:1623-7. [PMID: 24105702 DOI: 10.1002/humu.22445] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 09/09/2013] [Indexed: 11/08/2022]
Abstract
We describe a West syndrome (WS) patient with unidentified etiology that evolved to Lennox-Gastaut syndrome. The mitochondrial respiratory chain of the patient showed a simple complex I deficiency in fibroblasts. Whole-exome sequencing (WES) uncovered two heterozygous mutations in NDUFV2 gene that were reassigned to a pseudogene. With the WES data, it was possible to obtain whole mitochondrial DNA sequencing and to identify a heteroplasmic variant in the MT-ND1 (MTND1) gene (m.3946G>A, p.E214K). The expression of the gene in patient fibroblasts was not affected but the protein level was significantly reduced, suggesting that protein stability was affected by this mutation. The lower protein level also affected assembly of complex I and supercomplexes (I/III2 /IV and I/III2 ), leading to complex I deficiency. While ATP levels at steady state under stress conditions were not affected, the amount of ROS produced by complex I was significantly increased.
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Affiliation(s)
- Aitor Delmiro
- Laboratorio de Enfermedades Mitocondriales, Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, E-28041, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), U723, Madrid, E-28041, Spain
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186
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Novel mitochondrial C15620A variant may modulate the phenotype of mitochondrial G11778A mutation in a Chinese family with Leigh syndrome. Neuromolecular Med 2013; 16:119-26. [PMID: 24062162 DOI: 10.1007/s12017-013-8264-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 09/03/2013] [Indexed: 01/25/2023]
Abstract
We report a case of 3-year-old boy who presented with Leigh syndrome but carried a mitochondrial G11778A mutation in the fourth subunit of the NADH dehydrogenase gene (MTND4). Additional to G11778A mutation, a novel C15620A variant was detected, which resulted in the conversion from leucine to isoleucine in the mitochondrial cytochrome b gene. As G11778A mutation is the most common mutation associated with Leber's hereditary optic neuropathy (LHON), given the unusual phenotype, the C15620A mutation was postulated to influence the pathogenicity of the G11778A mutation. This case further expands the clinical spectrum associated with the primary G11778A LHON mutation.
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187
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Kallergi E, Kalef-Ezra E, Karagouni-Dalakoura K, Tokatlidis K. Common Players in Mitochondria Biogenesis and Neuronal Protection Against Stress-Induced Apoptosis. Neurochem Res 2013; 39:546-55. [DOI: 10.1007/s11064-013-1109-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/01/2013] [Accepted: 07/08/2013] [Indexed: 10/26/2022]
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188
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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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189
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Abstract
INTRODUCTION In the last 10 years the field of mitochondrial genetics has widened, shifting the focus from rare sporadic, metabolic disease to the effects of mitochondrial DNA (mtDNA) variation in a growing spectrum of human disease. The aim of this review is to guide the reader through some key concepts regarding mitochondria before introducing both classic and emerging mitochondrial disorders. SOURCES OF DATA In this article, a review of the current mitochondrial genetics literature was conducted using PubMed (http://www.ncbi.nlm.nih.gov/pubmed/). In addition, this review makes use of a growing number of publically available databases including MITOMAP, a human mitochondrial genome database (www.mitomap.org), the Human DNA polymerase Gamma Mutation Database (http://tools.niehs.nih.gov/polg/) and PhyloTree.org (www.phylotree.org), a repository of global mtDNA variation. AREAS OF AGREEMENT The disruption in cellular energy, resulting from defects in mtDNA or defects in the nuclear-encoded genes responsible for mitochondrial maintenance, manifests in a growing number of human diseases. AREAS OF CONTROVERSY The exact mechanisms which govern the inheritance of mtDNA are hotly debated. GROWING POINTS Although still in the early stages, the development of in vitro genetic manipulation could see an end to the inheritance of the most severe mtDNA disease.
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Affiliation(s)
| | - Gavin Hudson
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
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190
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Abstract
Phosphorylation of mitochondrial proteins has emerged as a major regulatory mechanism for metabolic adaptation. cAMP signaling and PKA phosphorylation of mitochondrial proteins have just started to be investigated, and the presence of cAMP-generating enzymes and PKA inside mitochondria is still controversial. Here, we discuss the role of cAMP in regulating mitochondrial bioenergetics through protein phosphorylation and the evidence for soluble adenylyl cyclase as the source of cAMP inside mitochondria.
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Affiliation(s)
- Federica Valsecchi
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, USA
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191
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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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