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Desmin Knock-Out Cardiomyopathy: A Heart on the Verge of Metabolic Crisis. Int J Mol Sci 2022; 23:ijms231912020. [PMID: 36233322 PMCID: PMC9570457 DOI: 10.3390/ijms231912020] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 09/30/2022] [Accepted: 10/02/2022] [Indexed: 12/05/2022] Open
Abstract
Desmin mutations cause familial and sporadic cardiomyopathies. In addition to perturbing the contractile apparatus, both desmin deficiency and mutated desmin negatively impact mitochondria. Impaired myocardial metabolism secondary to mitochondrial defects could conceivably exacerbate cardiac contractile dysfunction. We performed metabolic myocardial phenotyping in left ventricular cardiac muscle tissue in desmin knock-out mice. Our analyses revealed decreased mitochondrial number, ultrastructural mitochondrial defects, and impaired mitochondria-related metabolic pathways including fatty acid transport, activation, and catabolism. Glucose transporter 1 and hexokinase-1 expression and hexokinase activity were increased. While mitochondrial creatine kinase expression was reduced, fetal creatine kinase expression was increased. Proteomic analysis revealed reduced expression of proteins involved in electron transport mainly of complexes I and II, oxidative phosphorylation, citrate cycle, beta-oxidation including auxiliary pathways, amino acid catabolism, and redox reactions and oxidative stress. Thus, desmin deficiency elicits a secondary cardiac mitochondriopathy with severely impaired oxidative phosphorylation and fatty and amino acid metabolism. Increased glucose utilization and fetal creatine kinase upregulation likely portray attempts to maintain myocardial energy supply. It may be prudent to avoid medications worsening mitochondrial function and other metabolic stressors. Therapeutic interventions for mitochondriopathies might also improve the metabolic condition in desmin deficient hearts.
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Yalçınkaya B, Tastekin D, Güzelbulut F, Akgoz M, Pençe S. Quantification of cell-free circulating mitochondrial DNA copy number variation in hepatocellular carcinoma. Rev Assoc Med Bras (1992) 2022; 68:1161-1165. [PMID: 36228247 PMCID: PMC9575012 DOI: 10.1590/1806-9282.20210368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 05/16/2022] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVE Hepatocellular carcinoma is the most common primary malignant liver tumor. Mitochondrial DNA copy number has been shown to be associated with various malignancies. However, there has not been any study on the absolute quantification of mtDNA copy number in hepatocellular carcinoma. The aim of this study was to develop a new method for absolute quantification of mtDNA copy number and to relatively quantify the variations in the mtDNA copy number in hepatocellular carcinoma patients in comparison with healthy individuals. METHODS Venous blood samples were collected from both hepatocellular carcinoma patients (34) and healthy individuals (34). Circulating cell-free DNAs were isolated and the relative quantification of mtDNA copy number variation was determined using quantitative polymerase chain reaction and digital polymerase chain reaction. RESULTS It was found that the relative mtDNA copy number was significantly decreased in hepatocellular carcinoma patients in comparison with the control group (p<0.05). The median (range) and average of relative mtDNA/β-actin gene of the patients were determined as 42.8 cp/μL (11.1-88.5) and 45.1 cp/μL, respectively, while the median (range) and average relative mtDNA/β-actin gene of the control group were determined as 102.8 cp/μL (55.1-291.8) and 138.7 cp/μL, respectively (p<0.05). When quantitative polymerase chain reaction and digital polymerase chain reaction were compared, mtDNA/β-actin gene copy number ratio of digital polymerase chain reaction results was found to be 1.76-fold more than that of quantitative polymerase chain reaction results. CONCLUSION Circulating mtDNA copy number was decreased in hepatocellular carcinoma patients in comparison with healthy individuals, and we suggest that it can be used as a noninvasive biomarker for hepatocellular carcinoma diagnosis in the future.
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Affiliation(s)
| | - Didem Tastekin
- Istanbul University, Institute of Oncology – Istanbul, Turkey
| | - Fatih Güzelbulut
- University of Health Sciences, Haydarpaşa Numune Training and Research Hospital – Istanbul, Turkey
| | - Muslum Akgoz
- TUBITAK National Metrology Institute – Kocaeli, Turkey
| | - Sadrettin Pençe
- Istanbul Medeniyet University, Faculty of Medicine – Istanbul, Turkey
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Valiente-Pallejà A, Tortajada J, Bulduk BK, Vilella E, Garrabou G, Muntané G, Martorell L. Comprehensive summary of mitochondrial DNA alterations in the postmortem human brain: A systematic review. EBioMedicine 2022; 76:103815. [PMID: 35085849 PMCID: PMC8790490 DOI: 10.1016/j.ebiom.2022.103815] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/24/2021] [Accepted: 01/05/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) encodes 37 genes necessary for synthesizing 13 essential subunits of the oxidative phosphorylation system. mtDNA alterations are known to cause mitochondrial disease (MitD), a clinically heterogeneous group of disorders that often present with neuropsychiatric symptoms. Understanding the nature and frequency of mtDNA alterations in health and disease could be a cornerstone in disentangling the relationship between biochemical findings and clinical symptoms of brain disorders. This systematic review aimed to summarize the mtDNA alterations in human brain tissue reported to date that have implications for further research on the pathophysiological significance of mtDNA alterations in brain functioning. METHODS We searched the PubMed and Embase databases using distinct terms related to postmortem human brain and mtDNA up to June 10, 2021. Reports were eligible if they were empirical studies analysing mtDNA in postmortem human brains. FINDINGS A total of 158 of 637 studies fulfilled the inclusion criteria and were clustered into the following groups: MitD (48 entries), neurological diseases (NeuD, 55 entries), psychiatric diseases (PsyD, 15 entries), a miscellaneous group with controls and other clinical diseases (5 entries), ageing (20 entries), and technical issues (5 entries). Ten entries were ascribed to more than one group. Pathogenic single nucleotide variants (pSNVs), both homo- or heteroplasmic variants, have been widely reported in MitD, with heteroplasmy levels varying among brain regions; however, pSNVs are rarer in NeuD, PsyD and ageing. A lower mtDNA copy number (CN) in disease was described in most, but not all, of the identified studies. mtDNA deletions were identified in individuals in the four clinical categories and ageing. Notably, brain samples showed significantly more mtDNA deletions and at higher heteroplasmy percentages than blood samples, and several of the deletions present in the brain were not detected in the blood. Finally, mtDNA heteroplasmy, mtDNA CN and the deletion levels varied depending on the brain region studied. INTERPRETATION mtDNA alterations are well known to affect human tissues, including the brain. In general, we found that studies of MitD, NeuD, PsyD, and ageing were highly variable in terms of the type of disease or ageing process investigated, number of screened individuals, studied brain regions and technology used. In NeuD and PsyD, no particular type of mtDNA alteration could be unequivocally assigned to any specific disease or diagnostic group. However, the presence of mtDNA deletions and mtDNA CN variation imply a role for mtDNA in NeuD and PsyD. Heteroplasmy levels and threshold effects, affected brain regions, and mitotic segregation patterns of mtDNA alterations may be involved in the complex inheritance of NeuD and PsyD and in the ageing process. Therefore, more information is needed regarding the type of mtDNA alteration, the affected brain regions, the heteroplasmy levels, and their relationship with clinical phenotypes and the ageing process. FUNDING Hospital Universitari Institut Pere Mata; Institut d'Investigació Sanitària Pere Virgili; Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación (PI18/00514).
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Affiliation(s)
- Alba Valiente-Pallejà
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain
| | - Juan Tortajada
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain
| | - Bengisu K Bulduk
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain
| | - Elisabet Vilella
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain
| | - Glòria Garrabou
- Laboratory of Muscle Research and Mitochondrial Function, Department of Internal Medicine-Hospital Clínic of Barcelona (HCB); Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Faculty of Medicine and Health Sciences, Universitat de Barcelona (UB), 08036 Barcelona, Catalonia, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), 28029 Madrid, Spain
| | - Gerard Muntané
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain; Institute of Evolutionary Biology (IBE), Universitat Pompeu Fabra (UPF), 08003 Barcelona, Catalonia, Spain
| | - Lourdes Martorell
- Research Department, Hospital Universitari Institut Pere Mata (HUIPM); Institut d'Investigació Sanitària Pere Virgili (IISPV); Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), 43201 Reus, Catalonia, Spain; Biomedical Network Research Centre on Mental Health (CIBERSAM), 28029 Madrid, Spain.
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Debska-Vielhaber G, Miller I, Peeva V, Zuschratter W, Walczak J, Schreiber S, Petri S, Machts J, Vogt S, Szczepanowska J, Gellerich FN, Hermann A, Vielhaber S, Kunz WS. Impairment of mitochondrial oxidative phosphorylation in skin fibroblasts of SALS and FALS patients is rescued by in vitro treatment with ROS scavengers. Exp Neurol 2021; 339:113620. [PMID: 33497646 DOI: 10.1016/j.expneurol.2021.113620] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 12/22/2020] [Accepted: 01/19/2021] [Indexed: 11/19/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating, rapidly progressive, neurodegenerative disorder affecting upper and lower motor neurons. Approximately 10% of patients suffer from familial ALS (FALS) with mutations in different ubiquitously expressed genes including SOD1, C9ORF72, TARDBP, and FUS. There is compelling evidence for mitochondrial involvement in the pathogenic mechanisms of FALS and sporadic ALS (SALS), which is believed to be relevant for disease. Owing to the ubiquitous expression of relevant disease-associated genes, mitochondrial dysfunction is also detectable in peripheral patient tissue. We here report results of a detailed investigation of the functional impairment of mitochondrial oxidative phosphorylation (OXPHOS) in cultured skin fibroblasts from 23 SALS and 17 FALS patients, harboring pathogenic mutations in SOD1, C9ORF72, TARDBP and FUS. A considerable functional and structural mitochondrial impairment was detectable in fibroblasts from patients with SALS. Similarly, fibroblasts from patients with FALS, harboring pathogenic mutations in TARDBP, FUS and SOD1, showed mitochondrial defects, while fibroblasts from C9ORF72 associated FALS showed a very mild impairment detectable in mitochondrial ATP production rates only. While we could not detect alterations in the mtDNA copy number in the SALS or FALS fibroblast cultures, the impairment of OXPHOS in SALS fibroblasts and SOD1 or TARDBP FALS could be rescued by in vitro treatments with CoQ10 (5 μM for 3 weeks) or Trolox (300 μM for 5 days). This underlines the role of elevated oxidative stress as a potential cause for the observed functional effects on mitochondria, which might be relevant disease modifying factors.
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Affiliation(s)
- Grazyna Debska-Vielhaber
- Department of Neurology, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Irina Miller
- Department of Neurology, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany; Department of Neurosurgery, University Hospital Carl Gustav Carus Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Viktoriya Peeva
- Institute of Experimental Epileptology and Cognition Research, Life & Brain Center, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany
| | - Werner Zuschratter
- Leibniz Institute for Neurobiology, Laboratory for Electron- and Laserscanning- Microscopy, Brenneckestr.6, 39118 Magdeburg, Germany
| | - Jaroslaw Walczak
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St, 02-993 Warsaw, Poland; Institute of Fundamental Technological Research, Polish Academy of Sciences, 5b Pawińskiego St, 02-106 Warsaw, Poland
| | - Stefanie Schreiber
- Department of Neurology, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany; German Centre for Neurodegenerative Diseases (DZNE) Magdeburg, Leipziger Str.44, 39120 Magdeburg, Germany
| | - Susanne Petri
- Department of Neurology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Judith Machts
- Department of Neurology, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany; German Centre for Neurodegenerative Diseases (DZNE) Magdeburg, Leipziger Str.44, 39120 Magdeburg, Germany
| | - Susanne Vogt
- Department of Neurology, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Joanna Szczepanowska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St, 02-993 Warsaw, Poland
| | - Frank N Gellerich
- Department of Neurology, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Andreas Hermann
- Translational Neurodegeneration Section "Albrecht-Kossel", Department of Neurology and Center for Transdisciplinary Neurosciences Rostock (CTNR), University of Rostock, Gehlsheimer Straße 20, 18147 Rostock, Germany; German Centre for Neurodegenerative Diseases (DZNE) Rostock/Greifswald, Gehlsheimer Straße 20, 18147 Rostock, Germany
| | - Stefan Vielhaber
- Department of Neurology, Otto-von-Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany; German Centre for Neurodegenerative Diseases (DZNE) Magdeburg, Leipziger Str.44, 39120 Magdeburg, Germany.
| | - Wolfram S Kunz
- Institute of Experimental Epileptology and Cognition Research, Life & Brain Center, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany
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Stöckigt F, Eichhorn L, Beiert T, Knappe V, Radecke T, Steinmetz M, Nickenig G, Peeva V, Kudin AP, Kunz WS, Berwanger C, Kamm L, Schultheis D, Schlötzer-Schrehardt U, Clemen CS, Schröder R, Schrickel JW. Heart failure after pressure overload in autosomal-dominant desminopathies: Lessons from heterozygous DES-p.R349P knock-in mice. PLoS One 2020; 15:e0228913. [PMID: 32126091 PMCID: PMC7053759 DOI: 10.1371/journal.pone.0228913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/27/2020] [Indexed: 11/21/2022] Open
Abstract
Background Mutations in the human desmin gene (DES) cause autosomal-dominant and -recessive cardiomyopathies, leading to heart failure, arrhythmias, and AV blocks. We analyzed the effects of vascular pressure overload in a patient-mimicking p.R349P desmin knock-in mouse model that harbors the orthologue of the frequent human DES missense mutation p.R350P. Methods and results Transverse aortic constriction (TAC) was performed on heterozygous (HET) DES-p.R349P mice and wild-type (WT) littermates. Echocardiography demonstrated reduced left ventricular ejection fraction in HET-TAC (WT-sham: 69.5 ± 2.9%, HET-sham: 64.5 ± 4.7%, WT-TAC: 63.5 ± 4.9%, HET-TAC: 55.7 ± 5.4%; p<0.01). Cardiac output was significantly reduced in HET-TAC (WT sham: 13088 ± 2385 μl/min, HET sham: 10391 ± 1349μl/min, WT-TAC: 8097 ± 1903μl/min, HET-TAC: 5793 ± 2517μl/min; p<0.01). Incidence and duration of AV blocks as well as the probability to induce ventricular tachycardias was highest in HET-TAC. We observed reduced mtDNA copy numbers in HET-TAC (WT-sham: 12546 ± 406, HET-sham: 13526 ± 781, WT-TAC: 11155 ± 3315, HET-TAC: 8649 ± 1582; p = 0.025), but no mtDNA deletions. The activity of respiratory chain complexes I and IV showed the greatest reductions in HET-TAC. Conclusion Pressure overload in HET mice aggravated the clinical phenotype of cardiomyopathy and resulted in mitochondrial dysfunction. Preventive avoidance of pressure overload/arterial hypertension in desminopathy patients might represent a crucial therapeutic measure.
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Affiliation(s)
- Florian Stöckigt
- Department of Cardiology, University Hospital Bonn, Bonn, Germany
- Department of Cardiology, Krankenhaus Porz, Urbacher Weg, Cologne, Germany
- * E-mail:
| | - Lars Eichhorn
- Department of Anesthesiology, University Hospital Bonn, Bonn, Germany
| | - Thomas Beiert
- Department of Cardiology, University Hospital Bonn, Bonn, Germany
| | - Vincent Knappe
- Department of Cardiology, University Hospital Bonn, Bonn, Germany
| | - Tobias Radecke
- Department of Cardiology, University Hospital Essen, Hufelandstraße, Essen, Germany
| | - Martin Steinmetz
- Department of Cardiology, University Hospital Essen, Hufelandstraße, Essen, Germany
| | - Georg Nickenig
- Department of Cardiology, University Hospital Bonn, Bonn, Germany
| | - Viktoriya Peeva
- Institute of Experimental Epileptology and Cognition Research, Bonn, Germany
- Department of Epileptology, University Hospital of Bonn, Bonn, Germany
| | - Alexei P. Kudin
- Institute of Experimental Epileptology and Cognition Research, Bonn, Germany
- Department of Epileptology, University Hospital of Bonn, Bonn, Germany
| | - Wolfram S. Kunz
- Institute of Experimental Epileptology and Cognition Research, Bonn, Germany
- Department of Epileptology, University Hospital of Bonn, Bonn, Germany
| | - Carolin Berwanger
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, Cologne, Germany
| | - Lisa Kamm
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Schwabachanlage, Erlangen, Germany
| | - Dorothea Schultheis
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Schwabachanlage, Erlangen, Germany
| | - Ursula Schlötzer-Schrehardt
- Department of Opthalmology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Schwabachanlage, Erlangen, Germany
| | - Christoph S. Clemen
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, Cologne, Germany
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Schwabachanlage, Erlangen, Germany
- Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, Cologne, Germany
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Medical Faculty, University of Cologne, Cologne, Germany
| | - Rolf Schröder
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Schwabachanlage, Erlangen, Germany
| | - Jan W. Schrickel
- Department of Cardiology, University Hospital Bonn, Bonn, Germany
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Schlapakow E, Peeva V, Zsurka G, Jeub M, Wabbels B, Kornblum C, Kunz WS. Distinct segregation of the pathogenic m.5667G>A mitochondrial tRNA Asn mutation in extraocular and skeletal muscle in chronic progressive external ophthalmoplegia. Neuromuscul Disord 2019; 29:358-367. [PMID: 30962064 DOI: 10.1016/j.nmd.2019.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/08/2019] [Accepted: 02/19/2019] [Indexed: 12/13/2022]
Abstract
Chronic progressive external ophthalmoplegia (CPEO) is a frequent clinical manifestation of disorders caused by pathogenic mitochondrial DNA mutations. However, for diagnostic purposes skeletal muscle tissue is used, since extraocular muscle tissue is usually not available for work-up. In the present study we aimed to identify causative factors that are responsible for extraocular muscle to be primarily affected in CPEO. We performed comparative histochemical and molecular genetic analyses of extraocular muscle and skeletal muscle single fibers in a case of isolated CPEO caused by the heteroplasmic m.5667G>A mutation in the mitochondrial tRNAAsn gene (MT-TN). Histochemical analyses revealed higher proportion of cytochrome c oxidase deficient fibers in extraocular muscle (41%) compared to skeletal muscle (10%). However, genetic analyses of single fibers revealed no significant difference either in the mutation loads between extraocular muscle and skeletal muscle cytochrome c oxidase deficient single fibers (extraocular muscle 86% ± 4.6%; skeletal muscle 87.8 %± 5.7%, p = 0.246) nor in the mutation threshold (extraocular muscle 74% ± 3%; skeletal muscle 74% ± 4%). We hypothesize that higher proportion of cytochrome c oxidase deficient fibers in extraocular muscle compared to skeletal muscle might be due to facilitated segregation of the m.5667G>A mutation into extraocular muscle, which may explain the preferential ocular manifestation and clinically isolated CPEO.
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Affiliation(s)
- Elena Schlapakow
- Department of Neurology, University Hospital of Bonn, Germany; Center for Rare Diseases, University Hospital of Bonn, Germany
| | - Viktoriya Peeva
- Division of Neurochemistry, Institute of Experimental Epileptology and Cognition Research, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany
| | - Gábor Zsurka
- Division of Neurochemistry, Institute of Experimental Epileptology and Cognition Research, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany; Department of Epileptology, University of Bonn, Germany
| | - Monika Jeub
- Department of Neurology, University Hospital of Bonn, Germany
| | | | - Cornelia Kornblum
- Department of Neurology, University Hospital of Bonn, Germany; Center for Rare Diseases, University Hospital of Bonn, Germany
| | - Wolfram S Kunz
- Division of Neurochemistry, Institute of Experimental Epileptology and Cognition Research, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany; Department of Epileptology, University of Bonn, Germany.
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Yusuf M, Khan M, Robaian MA, Khan RA. Biomechanistic insights into the roles of oxidative stress in generating complex neurological disorders. Biol Chem 2018; 399:305-319. [PMID: 29261511 DOI: 10.1515/hsz-2017-0250] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Accepted: 12/07/2017] [Indexed: 12/13/2022]
Abstract
Neurological diseases like Alzheimer's disease, epilepsy, parkinsonism, depression, Huntington's disease and amyotrophic lateral sclerosis prevailing globally are considered to be deeply influenced by oxidative stress-based changes in the biochemical settings of the organs. The excess oxygen concentration triggers the production of reactive oxygen species, and even the intrinsic antioxidant enzyme system, i.e. SOD, CAT and GSHPx, fails to manage their levels and keep them under desirable limits. This consequently leads to oxidation of protein, lipids and nucleic acids in the brain resulting in apoptosis, proteopathy, proteasomes and mitochondrion dysfunction, glial cell activation as well as neuroinflammation. The present exploration deals with the evidence-based mechanism of oxidative stress towards development of key neurological diseases along with the involved biomechanistics and biomaterials.
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Affiliation(s)
- Mohammad Yusuf
- College of Pharmacy, Taif University, Taif-Al-Haweiah 21974, Saudi Arabia
| | - Maria Khan
- College of Pharmacy, Taif University, Taif-Al-Haweiah 21974, Saudi Arabia
| | - Majed A Robaian
- College of Pharmacy, Taif University, Taif-Al-Haweiah 21974, Saudi Arabia
| | - Riaz A Khan
- Medicinal Chemistry Department, Qassim University, Qassim 51452, Saudi Arabia
- Department of Chemistry, MRIU, Faridabad, HR 121 001, India
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Kudin AP, Mawasi H, Eisenkraft A, Elger CE, Bialer M, Kunz WS. Mitochondrial Liver Toxicity of Valproic Acid and Its Acid Derivatives Is Related to Inhibition of α-Lipoamide Dehydrogenase. Int J Mol Sci 2017; 18:ijms18091912. [PMID: 28878165 PMCID: PMC5618561 DOI: 10.3390/ijms18091912] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/01/2017] [Accepted: 09/03/2017] [Indexed: 11/16/2022] Open
Abstract
The liver toxicity of valproic acid (VPA) is an established side effect of this widely used antiepileptic drug, which is extremely problematic for patients with metabolic epilepsy and particularly epilepsy due to mitochondrial dysfunction. In the present report, we investigated the reason for liver mitochondrial toxicity of VPA and several acid and amide VPA analogues. While the pyruvate and 2-oxoglutarate oxidation rates of rat brain mitochondria were nearly unaffected by VPA, rat liver mitochondrial pyruvate and 2-oxoglutarate oxidation was severely impaired by VPA concentrations above 100 µM. Among the reactions involved in pyruvate oxidation, pyruvate transport and dehydrogenation steps were not affected by VPA, while α-lipoamide dehydrogenase was strongly inhibited. Strong inhibition of α-lipoamide dehydrogenase was also noted for the VPA one-carbon homolog sec -butylpropylacetic acid (SPA) and to a lesser extent for the VPA constitutional isomer valnoctic acid (VCA), while the corresponding amides of the above three acids valpromide (VPD), sec -butylpropylacetamide (SPD) and valnoctamide (VCD) showed only small effects. We conclude that the active inhibitors of pyruvate and 2-oxoglutarate oxidation are the CoA conjugates of VPA and its acid analogues affecting selectively α-lipoamide dehydrogenase in liver. Amide analogues of VPA, like VCD, show low inhibitory effects on mitochondrial oxidative phosphorylation in the liver, which might be relevant for treatment of patients with mitochondrial epilepsy.
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Affiliation(s)
- Alexei P Kudin
- Department of Epileptology and Life & Brain Center, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany.
| | - Hafiz Mawasi
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
| | - Arik Eisenkraft
- Institute for Research in Military Medicine, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
| | - Christian E Elger
- Department of Epileptology and Life & Brain Center, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany.
| | - Meir Bialer
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
| | - Wolfram S Kunz
- Department of Epileptology and Life & Brain Center, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany.
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Beręsewicz M, Boratyńska-Jasińska A, Charzewski Ł, Kawalec M, Kabzińska D, Kochański A, Krzyśko KA, Zabłocka B. The Effect of a Novel c.820C>T (Arg274Trp) Mutation in the Mitofusin 2 Gene on Fibroblast Metabolism and Clinical Manifestation in a Patient. PLoS One 2017; 12:e0169999. [PMID: 28076385 PMCID: PMC5226824 DOI: 10.1371/journal.pone.0169999] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 12/27/2016] [Indexed: 12/04/2022] Open
Abstract
Charcot-Marie-Tooth disease type 2A (CMT2A) is an autosomal dominant axonal peripheral neuropathy caused by mutations in the mitofusin 2 gene (MFN2). Mitofusin 2 is a GTPase protein present in the outer mitochondrial membrane and responsible for regulation of mitochondrial network architecture via the fusion of mitochondria. As that fusion process is known to be strongly dependent on the GTPase activity of mitofusin 2, it is postulated that the MFN2 mutation within the GTPase domain may lead to impaired GTPase activity, and in turn to mitochondrial dysfunction. The work described here has therefore sought to verify the effects of MFN2 mutation within its GTPase domain on mitochondrial and endoplasmic reticulum morphology, as well as the mtDNA content in a cultured primary fibroblast obtained from a CMT2A patient harboring a de novo Arg274Trp mutation. In fact, all the parameters studied were affected significantly by the presence of the mutant MFN2 protein. However, using the stable model for mitofusin 2 obtained by us, we were next able to determine that the Arg274Trp mutation does not impact directly upon GTP binding. Such results were also confirmed for GTP-hydrolysis activity of MFN2 protein in patient fibroblast. We therefore suggest that the biological malfunctions observable with the disease are not consequences of impaired GTPase activity, but rather reflect an impaired contribution of the GTPase domain to other MFN2 activities involving that region, for example protein-protein interactions.
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Affiliation(s)
| | | | | | - Maria Kawalec
- Molecular Biology Unit, Mossakowski Medical Research Centre, PAS, Warsaw, Poland
| | - Dagmara Kabzińska
- Neuromuscular Unit, Mossakowski Medical Research Centre, PAS, Warsaw, Poland
| | - Andrzej Kochański
- Neuromuscular Unit, Mossakowski Medical Research Centre, PAS, Warsaw, Poland
| | | | - Barbara Zabłocka
- Molecular Biology Unit, Mossakowski Medical Research Centre, PAS, Warsaw, Poland
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10
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Mutant desmin substantially perturbs mitochondrial morphology, function and maintenance in skeletal muscle tissue. Acta Neuropathol 2016; 132:453-73. [PMID: 27393313 PMCID: PMC4992032 DOI: 10.1007/s00401-016-1592-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 06/23/2016] [Accepted: 06/24/2016] [Indexed: 12/18/2022]
Abstract
Secondary mitochondrial dysfunction is a feature in a wide variety of human protein aggregate diseases caused by mutations in different proteins, both in the central nervous system and in striated muscle. The functional relationship between the expression of a mutated protein and mitochondrial dysfunction is largely unknown. In particular, the mechanism how this dysfunction drives the disease process is still elusive. To address this issue for protein aggregate myopathies, we performed a comprehensive, multi-level analysis of mitochondrial pathology in skeletal muscles of human patients with mutations in the intermediate filament protein desmin and in muscles of hetero- and homozygous knock-in mice carrying the R349P desmin mutation. We demonstrate that the expression of mutant desmin causes disruption of the extrasarcomeric desmin cytoskeleton and extensive mitochondrial abnormalities regarding subcellular distribution, number and shape. At the molecular level, we uncovered changes in the abundancy and assembly of the respiratory chain complexes and supercomplexes. In addition, we revealed a marked reduction of mtDNA- and nuclear DNA-encoded mitochondrial proteins in parallel with large-scale deletions in mtDNA and reduced mtDNA copy numbers. Hence, our data demonstrate that the expression of mutant desmin causes multi-level damage of mitochondria already in early stages of desminopathies.
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11
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Volmering E, Niehusmann P, Peeva V, Grote A, Zsurka G, Altmüller J, Nürnberg P, Becker AJ, Schoch S, Elger CE, Kunz WS. Neuropathological signs of inflammation correlate with mitochondrial DNA deletions in mesial temporal lobe epilepsy. Acta Neuropathol 2016; 132:277-288. [PMID: 26993140 DOI: 10.1007/s00401-016-1561-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/26/2016] [Accepted: 03/11/2016] [Indexed: 11/27/2022]
Abstract
Accumulation of mitochondrial DNA (mtDNA) deletions has been proposed to be responsible for the presence of respiratory-deficient neurons in several CNS diseases. Deletions are thought to originate from double-strand breaks due to attack of reactive oxygen species (ROS) of putative inflammatory origin. In epileptogenesis, emerging evidence points to chronic inflammation as an important feature. Here we aimed to analyze the potential association of inflammation and mtDNA deletions in the hippocampal tissue of patients with mesial temporal lobe epilepsy (mTLE) and hippocampal sclerosis (HS). Hippocampal and parahippocampal tissue samples from 74 patients with drug-refractory mTLE served for mtDNA analysis by multiplex PCR as well as long-range PCR, single-molecule PCR and ultra-deep sequencing of mtDNA in selected samples. Patients were sub-classified according to neuropathological findings. Semi-quantitative assessment of neuronal cell loss was performed in the hippocampal regions CA1-CA4. Inflammatory infiltrates were quantified by cell counts in the CA1, CA3 and CA4 regions from well preserved hippocampal samples (n = 33). Samples with HS showed a significantly increased frequency of a 7436-bp mtDNA deletion (p < 0.0001) and a higher proportion of somatic G>T transversions compared to mTLE patients with different histopathology. Interestingly, the number of T-lymphocytes in the hippocampal CA1, CA3 and CA4 regions was, similar to the 7436-bp mtDNA deletion, significantly increased in samples with HS compared to other subgroups. Our findings show a coincidence of HS, increased somatic G>T transversions, the presence of a specific mtDNA deletion, and increased inflammatory infiltrates. These results support the hypothesis that chronic inflammation leads to mitochondrial dysfunction by ROS-mediated mtDNA mutagenesis which promotes epileptogenesis and neuronal cell loss in patients with mTLE and HS.
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Affiliation(s)
- Elisa Volmering
- Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Pitt Niehusmann
- Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
- Department of Neuro-/Pathology, Oslo University Hospital, Oslo, Norway
| | - Viktoriya Peeva
- Division of Neurochemistry, Department of Epileptology, University Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
| | - Alexander Grote
- Department of Neurosurgery, University of Bonn Medical Center, Bonn, Germany
| | - Gábor Zsurka
- Division of Neurochemistry, Department of Epileptology, University Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Institute of Human Genetics, University of Cologne, Cologne, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Albert J Becker
- Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
- Translational Epilepsy Research Section, University of Bonn Medical Center, Bonn, Germany
| | - Susanne Schoch
- Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
- Translational Epilepsy Research Section, University of Bonn Medical Center, Bonn, Germany
| | - Christian E Elger
- Division of Neurochemistry, Department of Epileptology, University Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
| | - Wolfram S Kunz
- Division of Neurochemistry, Department of Epileptology, University Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.
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12
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Nicholls TJ, Zsurka G, Peeva V, Schöler S, Szczesny RJ, Cysewski D, Reyes A, Kornblum C, Sciacco M, Moggio M, Dziembowski A, Kunz WS, Minczuk M. Linear mtDNA fragments and unusual mtDNA rearrangements associated with pathological deficiency of MGME1 exonuclease. Hum Mol Genet 2014; 23:6147-62. [PMID: 24986917 PMCID: PMC4222359 DOI: 10.1093/hmg/ddu336] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
MGME1, also known as Ddk1 or C20orf72, is a mitochondrial exonuclease found to be involved in the processing of mitochondrial DNA (mtDNA) during replication. Here, we present detailed insights on the role of MGME1 in mtDNA maintenance. Upon loss of MGME1, elongated 7S DNA species accumulate owing to incomplete processing of 5′ ends. Moreover, an 11-kb linear mtDNA fragment spanning the entire major arc of the mitochondrial genome is generated. In contrast to control cells, where linear mtDNA molecules are detectable only after nuclease S1 treatment, the 11-kb fragment persists in MGME1-deficient cells. In parallel, we observed characteristic mtDNA duplications in the absence of MGME1. The fact that the breakpoints of these mtDNA rearrangements do not correspond to either classical deletions or the ends of the linear 11-kb fragment points to a role of MGME1 in processing mtDNA ends, possibly enabling their repair by homologous recombination. In agreement with its functional involvement in mtDNA maintenance, we show that MGME1 interacts with the mitochondrial replicase PolgA, suggesting that it is a constituent of the mitochondrial replisome, to which it provides an additional exonuclease activity. Thus, our results support the viewpoint that MGME1-mediated mtDNA processing is essential for faithful mitochondrial genome replication and might be required for intramolecular recombination of mtDNA.
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Affiliation(s)
| | - Gábor Zsurka
- Department of Epileptology, Life and Brain Center and
| | | | | | - Roman J Szczesny
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland and
| | - Dominik Cysewski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland and
| | - Aurelio Reyes
- Mitochondrial Biology Unit, Medical Research Council, Cambridge, UK
| | - Cornelia Kornblum
- Department of Neurology, University of Bonn Medical Center, Bonn, Germany
| | - Monica Sciacco
- Neuromuscular Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Centro Dino Ferrari, University of Milan, Milan, Italy
| | - Maurizio Moggio
- Neuromuscular Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Centro Dino Ferrari, University of Milan, Milan, Italy
| | - Andrzej Dziembowski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland and
| | | | - Michal Minczuk
- Mitochondrial Biology Unit, Medical Research Council, Cambridge, UK,
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13
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Tzoulis C, Tran GT, Coxhead J, Bertelsen B, Lilleng PK, Balafkan N, Payne B, Miletic H, Chinnery PF, Bindoff LA. Molecular pathogenesis of polymerase γ-related neurodegeneration. Ann Neurol 2014; 76:66-81. [PMID: 24841123 PMCID: PMC4140551 DOI: 10.1002/ana.24185] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/17/2014] [Accepted: 05/18/2014] [Indexed: 12/20/2022]
Abstract
Objective Polymerase gamma (POLG) mutations are a common cause of mitochondrial disease and have also been linked to neurodegeneration and aging. We studied the molecular mechanisms underlying POLG-related neurodegeneration using postmortem tissue from a large number of patients. Methods Clinical information was available from all subjects. Formalin-fixed and frozen brain tissue from 15 patients and 23 controls was studied employing a combination of histopathology, immunohistochemistry, and molecular studies of microdissected neurons. Results The primary consequence of POLG mutation in neurons is mitochondrial DNA depletion. This was already present in infants with little evidence of neuronal loss or mitochondrial dysfunction. With longer disease duration, we found an additional, progressive accumulation of mitochondrial DNA deletions and point mutations accompanied by increasing numbers of complex I–deficient neurons. Progressive neurodegeneration primarily affected the cerebellar systems and dopaminergic cells of the substantia nigra. Superimposed on this chronic process were acute, focal cortical lesions that correlated with epileptogenic foci and that showed massive neuronal loss. Interpretation POLG mutations appear to compromise neuronal respiration via a combination of early and stable depletion and a progressive somatic mutagenesis of the mitochondrial genome. This leads to 2 distinct but overlapping biological processes: a chronic neurodegeneration reflected clinically by progressive ataxia and cognitive impairment, and an acute focal neuronal necrosis that appears to be related to the presence of epileptic seizures. Our findings offer an explanation of the acute-on-chronic clinical course of this common mitochondrial encephalopathy. ANN NEUROL 2014;76:66–81
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Affiliation(s)
- Charalampos Tzoulis
- Department of Neurology, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway
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14
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Nanau RM, Neuman MG. Adverse drug reactions induced by valproic acid. Clin Biochem 2013; 46:1323-38. [PMID: 23792104 DOI: 10.1016/j.clinbiochem.2013.06.012] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 06/11/2013] [Accepted: 06/12/2013] [Indexed: 12/11/2022]
Abstract
Valproic acid is a widely-used first-generation antiepileptic drug, prescribed predominantly in epilepsy and psychiatric disorders. VPA has good efficacy and pharmacoeconomic profiles, as well as a relatively favorable safety profile. However, adverse drug reactions have been reported in relation with valproic acid use, either as monotherapy or polytherapy with other antiepileptic drugs or antipsychotic drugs. This systematic review discusses valproic acid adverse drug reactions, in terms of hepatotoxicity, mitochondrial toxicity, hyperammonemic encephalopathy, hypersensitivity syndrome reactions, neurological toxicity, metabolic and endocrine adverse events, and teratogenicity.
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Affiliation(s)
- Radu M Nanau
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, In Vitro Drug Safety and Biotechnology, Toronto, Ontario, Canada
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15
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Vielhaber S, Debska-Vielhaber G, Peeva V, Schoeler S, Kudin AP, Minin I, Schreiber S, Dengler R, Kollewe K, Zuschratter W, Kornblum C, Zsurka G, Kunz WS. Mitofusin 2 mutations affect mitochondrial function by mitochondrial DNA depletion. Acta Neuropathol 2013; 125:245-56. [PMID: 22926664 DOI: 10.1007/s00401-012-1036-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 07/13/2012] [Accepted: 08/18/2012] [Indexed: 12/01/2022]
Abstract
Charcot-Marie-Tooth neuropathy type 2A (CMT2A) is associated with heterozygous mutations in the mitochondrial protein mitofusin 2 (Mfn2) that is intimately involved with the outer mitochondrial membrane fusion machinery. The precise consequences of these mutations on oxidative phosphorylation are still a matter of dispute. Here, we investigate the functional effects of MFN2 mutations in skeletal muscle and cultured fibroblasts of four CMT2A patients applying high-resolution respirometry. While maximal activities of respiration of saponin-permeabilized muscle fibers and digitonin-permeabilized fibroblasts were only slightly affected by the MFN2 mutations, the sensitivity of active state oxygen consumption to azide, a cytochrome c oxidase (COX) inhibitor, was increased. The observed dysfunction of the mitochondrial respiratory chain can be explained by a twofold decrease in mitochondrial DNA (mtDNA) copy numbers. The only patient without detectable alterations of respiratory chain in skeletal muscle also had a normal mtDNA copy number. We detected higher levels of mtDNA deletions in CMT2A patients, which were more pronounced in the patient without mtDNA depletion. Detailed analysis of mtDNA deletion breakpoints showed that many deleted molecules were lacking essential parts of mtDNA required for replication. This is in line with the lack of clonal expansion for the majority of observed mtDNA deletions. In contrast to the copy number reduction, deletions are unlikely to contribute to the detected respiratory impairment because of their minor overall amounts in the patients. Taken together, our findings corroborate the hypothesis that MFN2 mutations alter mitochondrial oxidative phosphorylation by affecting mtDNA replication.
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Affiliation(s)
- Stefan Vielhaber
- Department of Neurology, University of Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
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16
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Maléth J, Rakonczay Z, Venglovecz V, Dolman NJ, Hegyi P. Central role of mitochondrial injury in the pathogenesis of acute pancreatitis. Acta Physiol (Oxf) 2013; 207:226-35. [PMID: 23167280 DOI: 10.1111/apha.12037] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 10/26/2012] [Accepted: 10/30/2012] [Indexed: 12/11/2022]
Abstract
Acute pancreatitis is an inflammatory disease with no specific treatment. One of the main reasons behind the lack of specific therapy is that the pathogenesis of acute pancreatitis is poorly understood. During the development of acute pancreatitis, the disease-inducing factors can damage both cell types of the exocrine pancreas, namely the acinar and ductal cells. Because damage of either of the cell types can contribute to the inflammation, it is crucial to find common intracellular mechanisms that can be targeted by pharmacological therapies. Despite the many differences, recent studies revealed that the most common factors that induce pancreatitis cause mitochondrial damage with the consequent breakdown of bioenergetics, that is, ATP depletion in both cell types. In this review, we summarize our knowledge of mitochondrial function and damage within both pancreatic acinar and ductal cells. We also suggest that colloidal ATP delivery systems for pancreatic energy supply may be able to protect acinar and ductal cells from cellular damage in the early phase of the disease. An effective energy delivery system combined with the prevention of further mitochondrial damage may, for the first time, open up the possibility of pharmacological therapy for acute pancreatitis, leading to reduced disease severity and mortality.
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Affiliation(s)
- J. Maléth
- First Department of Medicine; University of Szeged; Szeged; Hungary
| | - Z. Rakonczay
- First Department of Medicine; University of Szeged; Szeged; Hungary
| | - V. Venglovecz
- Department of Pharmacology and Pharmacotherapy; University of Szeged; Szeged; Hungary
| | - N. J. Dolman
- Molecular Probes Labelling and Detection Technologies; Life Technologies Corporation; Eugene; OR; USA
| | - P. Hegyi
- First Department of Medicine; University of Szeged; Szeged; Hungary
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17
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Zsurka G, Kunz WS. Mitochondrial involvement in neurodegenerative diseases. IUBMB Life 2013; 65:263-72. [PMID: 23341346 DOI: 10.1002/iub.1126] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 12/06/2012] [Accepted: 12/06/2012] [Indexed: 01/12/2023]
Abstract
The classical bioenergetical view of the involvement of mitochondria in neurogeneration is based on the fact that mitochondria are the central players of ATP synthesis in neurons and their failure leads to neuronal dysfunction and eventually to cell death. Mutations in at least 39 genes in inherited neurodegenerative disorders seem to alter directly or indirectly mitochondrial function. Most of these mutations do not directly affect oxidative phosphorylation, but act through disturbed mitochondrial dynamics and quality control. This, however, does not invalidate the bioenergetic hypothesis. Neurodegeneration is not necessarily associated with a gross failure of ATP production, but might rather be a consequence of local insufficiencies of ATP supply in critical compartments of neurons, like the presynaptic terminal. We hypothesize that slow disease progression, at least in a subgroup of neurodegenerative diseases, can be explained by the parallel action of subcellular ATP insufficiency and clonal expansion of somatic mitochondrial DNA mutations, and particularly deletions.
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Affiliation(s)
- Gábor Zsurka
- Department of Epileptology and Life and Brain Center, University Bonn, Bonn, Germany
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18
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Loss-of-function mutations in MGME1 impair mtDNA replication and cause multisystemic mitochondrial disease. Nat Genet 2013; 45:214-9. [PMID: 23313956 DOI: 10.1038/ng.2501] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 11/28/2012] [Indexed: 12/17/2022]
Abstract
Known disease mechanisms in mitochondrial DNA (mtDNA) maintenance disorders alter either the mitochondrial replication machinery (POLG, POLG2 and C10orf2) or the biosynthesis pathways of deoxyribonucleoside 5'-triphosphates for mtDNA synthesis. However, in many of these disorders, the underlying genetic defect has yet to be discovered. Here, we identify homozygous nonsense and missense mutations in the orphan gene C20orf72 in three families with a mitochondrial syndrome characterized by external ophthalmoplegia, emaciation and respiratory failure. Muscle biopsies showed mtDNA depletion and multiple mtDNA deletions. C20orf72, hereafter MGME1 (mitochondrial genome maintenance exonuclease 1), encodes a mitochondrial RecB-type exonuclease belonging to the PD-(D/E)XK nuclease superfamily. We show that MGME1 cleaves single-stranded DNA and processes DNA flap substrates. Fibroblasts from affected individuals do not repopulate after chemically induced mtDNA depletion. They also accumulate intermediates of stalled replication and show increased levels of 7S DNA, as do MGME1-depleted cells. Thus, we show that MGME1-mediated mtDNA processing is essential for mitochondrial genome maintenance.
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19
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Number of CAG repeats in POLG1 and its association with Parkinson disease in the Norwegian population. Mitochondrion 2012; 12:640-3. [PMID: 22963882 DOI: 10.1016/j.mito.2012.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Revised: 07/27/2012] [Accepted: 08/22/2012] [Indexed: 11/22/2022]
Abstract
The number of CAG repeats in the mitochondrial DNA-polymerase gamma (POLG1) gene has been associated with Parkinson disease (PD) in some populations. We sequenced the CAG tract of POLG1 in 191 Norwegian patients with PD and an equal number of controls and found an association between non-10 or 11 CAG repeats and PD in our population. While our results were significant, this trend was not maintained following correction for multiple testing. We also performed a meta-analysis of all published studies including our own that shows PD is associated with the number of CAG repeats in POLG1. The meta-analysis reveals that the rare allelic variation encompassed by non-10 CAG repeats associates significantly with PD (p=0.0017). Whether this reflects a direct influence of POLG on the pathogenesis of PD or linkage disequilibrium between POLG1 alleles and nearby, disease-influencing genetic variants remains unknown.
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20
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Oxidative stress and epilepsy: literature review. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:795259. [PMID: 22848783 PMCID: PMC3403512 DOI: 10.1155/2012/795259] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/07/2012] [Accepted: 05/24/2012] [Indexed: 11/21/2022]
Abstract
Backgrounds. The production of free radicals has a role in the regulation of biological function, cellular damage, and the pathogenesis of central nervous system conditions. Epilepsy is a highly prevalent serious brain disorder, and oxidative stress is regarded as a possible mechanism involved in epileptogenesis. Experimental studies suggest that oxidative stress is a contributing factor to the onset and evolution of epilepsy. Objective. A review was conducted to investigate the link between oxidative stress and seizures, and oxidative stress and age as risk factors for epilepsy. The role of oxidative stress in seizure induction and propagation is also discussed. Results/Conclusions. Oxidative stress and mitochondrial dysfunction are involved in neuronal death and seizures. There is evidence that suggests that antioxidant therapy may reduce lesions induced by oxidative free radicals in some animal seizure models. Studies have demonstrated that mitochondrial dysfunction is associated with chronic oxidative stress and may have an essential role in the epileptogenesis process; however, few studies have shown an established link between oxidative stress, seizures, and age.
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21
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Affiliation(s)
- Richard E. Frye
- Department of Pediatrics Division of Child and Adolescent Neurology and the Children’s Learning Institute, University of Texas Health Science Center, Houston, TX, USA
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22
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Oliveira MT, Kaguni LS. Reduced stimulation of recombinant DNA polymerase γ and mitochondrial DNA (mtDNA) helicase by variants of mitochondrial single-stranded DNA-binding protein (mtSSB) correlates with defects in mtDNA replication in animal cells. J Biol Chem 2011; 286:40649-58. [PMID: 21953457 DOI: 10.1074/jbc.m111.289983] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mitochondrial single-stranded DNA-binding protein (mtSSB) is believed to coordinate the functions of DNA polymerase γ (pol γ) and the mitochondrial DNA (mtDNA) helicase at the mtDNA replication fork. We generated five variants of the human mtSSB bearing mutations in amino acid residues specific to metazoans that map on the protein surface, removed from the single-stranded DNA (ssDNA) binding groove. Although the mtSSB variants bound ssDNA with only slightly different affinities, they exhibited distinct capacities to stimulate the DNA polymerase activity of human pol γ and the DNA unwinding activity of human mtDNA helicase in vitro. Interestingly, we observed that the variants with defects in stimulating pol γ had unaltered capacities to stimulate the mtDNA helicase; at the same time, variants showing reduced stimulation of the mtDNA helicase activity promoted DNA synthesis by pol γ similarly to the wild-type mtSSB. The overexpression of the equivalent variants of Drosophila melanogaster mtSSB in S2 cells in culture caused mtDNA depletion under conditions of mitochondrial homeostasis. Furthermore, we observed more severe reduction of mtDNA copy number upon expression of these proteins during recovery from treatment with ethidium bromide, when mtDNA replication is stimulated in vivo. Our findings suggest that mtSSB uses distinct structural elements to interact functionally with its mtDNA replisome partners and to promote proper mtDNA replication in animal cells.
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Affiliation(s)
- Marcos T Oliveira
- Department of Biochemistry and Molecular Biology, Center for Mitochondrial Science and Medicine, and Graduate Program in Genetics, Michigan State University, East Lansing, Michigan 48824-1319, USA
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Folbergrová J, Kunz WS. Mitochondrial dysfunction in epilepsy. Mitochondrion 2011; 12:35-40. [PMID: 21530687 DOI: 10.1016/j.mito.2011.04.004] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 02/16/2011] [Accepted: 04/14/2011] [Indexed: 11/29/2022]
Abstract
Mitochondrial dysfunction has been identified as one potential cause of epileptic seizures. Impaired mitochondrial function has been reported for the seizure focus of patients with temporal lobe epilepsy and Ammon's horn sclerosis and of adult and immature animal models of epilepsy. Since mitochondrial oxidative phosphorylation provides the major source of ATP in neurons and mitochondria participate in cellular Ca(2+) homeostasis and generation of reactive oxygen species, their dysfunction strongly affects neuronal excitability and synaptic transmission. Therefore, mitochondrial dysfunction is proposed to be highly relevant for seizure generation. Additionally, mitochondrial dysfunction is known to trigger neuronal cell death, which is a prominent feature of therapy-resistant epilepsy. For this reason mitochondria have to be considered as promising targets for neuroprotective strategies in epilepsy.
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Affiliation(s)
- Jaroslava Folbergrová
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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24
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Cunningham MO, Chinnery PF. Mitochondria and cortical gamma oscillations: food for thought? Brain 2011; 134:330-2. [PMID: 21278404 DOI: 10.1093/brain/awq382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Mark O Cunningham
- Institute of Neuroscience, The Medical School, Framlington Place, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
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25
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Schildgen V, Wulfert M, Gattermann N. Impaired mitochondrial gene transcription in myelodysplastic syndromes and acute myeloid leukemia with myelodysplasia-related changes. Exp Hematol 2011; 39:666-675.e1. [PMID: 21447369 DOI: 10.1016/j.exphem.2011.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 02/26/2011] [Accepted: 03/15/2011] [Indexed: 01/26/2023]
Abstract
OBJECTIVE To examine mitochondrial gene expression in hematopoietic progenitor cells of patients with myelodysplastic syndromes (MDS). Mitochondrial pathology in MDS is suggested by abnormal mitochondrial iron accumulation, increased apoptosis, and a high frequency of acquired mitochondrial DNA mutations in bone marrow cells. MATERIALS AND METHODS Mitochondrial gene expression was measured by real-time reverse transcription polymerase chain reaction in CD34(+) bone marrow cells from 37 patients with MDS (22 refractory cytopenia with multilineage dysplasia, 9 refractory anemia with excess of blasts [5-9% marrow blasts], 6 refractory anemia with excess of blasts [10-19% marrow blasts]), 14 cases of acute myeloid leukemia with myelodysplasia-related changes (acute myeloid leukemia-MDS), and 9 normal controls. Relative quantification was achieved by using specific plasmid standards and 18S ribosomal RNA. Genes were selected to represent the multi-enzyme complexes I to IV of the mitochondrial respiratory chain: nicotinamide adenine dinucleotide dehydrogenase subunit 3 (subunit of complex I), succinate dehydrogenase B (complex II), cytochrome B (complex III), and cytochrome-c-oxidase subunit I (complex IV). RESULTS Expression of mitochondrial-encoded genes was significantly reduced in patients with MDS and acute myeloid leukemia-MDS compared to normal controls, while mitochondrial DNA copy number was increased rather than diminished. An age-related decrease in mitochondrial gene expression was observed in MDS patients as well as controls. However, this effect was less pronounced than the MDS-related effect. Besides an overall decrease in mitochondrial gene expression, MDS patients displayed a stochiometric imbalance of mitochondrial-encoded genes, assessed in relation to the nuclear-encoded succinate dehydrogenase B. CONCLUSIONS Our results show dysregulated mitochondrial gene expression that goes beyond a simple age-related effect and is compatible with the putative role of mitochondrial dysfunction in MDS pathophysiology. However, it remains unclear whether the problem arises from primary lesions in the mitochondria, i.e., mitochondrial DNA mutations, or as a result of changes in the cell nucleus.
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Affiliation(s)
- Verena Schildgen
- Institut für Pathologie, Kliniken der Stadt Köln gGmbH, Köln, Germany.
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26
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POLG mutations cause decreased mitochondrial DNA repopulation rates following induced depletion in human fibroblasts. Biochim Biophys Acta Mol Basis Dis 2010; 1812:321-5. [PMID: 21138766 DOI: 10.1016/j.bbadis.2010.11.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Revised: 11/09/2010] [Accepted: 11/29/2010] [Indexed: 11/22/2022]
Abstract
Disorders of mitochondrial DNA (mtDNA) maintenance have emerged as an important cause of human genetic disease, but demonstrating the functional consequences of de novo mutations remains a major challenge. We studied the rate of depletion and repopulation of mtDNA in human fibroblasts exposed to ethidium bromide in patients with heterozygous POLG mutations, POLG2 and TK2 mutations. Ethidium bromide induced mtDNA depletion occurred at the same rate in human fibroblasts from patients and healthy controls. By contrast, the restoration of mtDNA levels was markedly delayed in fibroblasts from patients with compound heterozygous POLG mutations. Specific POLG2 and TK2 mutations did not delay mtDNA repopulation rates. These observations are consistent with the hypothesis that mutations in POLG impair mtDNA repopulation within intact cells, and provide a potential method of demonstrating the functional consequences of putative pathogenic alleles causing a defect of mtDNA synthesis.
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27
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Zsurka G, Kunz WS. Mitochondrial dysfunction in neurological disorders with epileptic phenotypes. J Bioenerg Biomembr 2010; 42:443-8. [DOI: 10.1007/s10863-010-9314-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Pyle A, Burn DJ, Gordon C, Swan C, Chinnery PF, Baudouin SV. Fall in circulating mononuclear cell mitochondrial DNA content in human sepsis. Intensive Care Med 2010; 36:956-62. [PMID: 20224905 PMCID: PMC4034433 DOI: 10.1007/s00134-010-1823-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 01/19/2010] [Indexed: 12/30/2022]
Abstract
PURPOSE Loss of mitochondrial DNA (mtDNA) has been described in whole blood samples from a small number of patients with sepsis, but the underlying mechanism and clinical implications of this observation are not clear. We have investigated the cellular basis of the mtDNA depletion in sepsis, and determined clinical correlates with mtDNA depletion. METHODS Whole blood samples were obtained from 147 consecutive patients with severe sepsis admitted to a General Critical Care Unit in a University Hospital and 83 healthy controls. In a separate study of 13 patients with severe sepsis, blood was obtained for immediate cell sorting by flow cytometry. MtDNA content was determined in whole blood DNA by PCR methods, and subsequently in the 13 samples where white cell subtypes were separated. RESULTS The mtDNA content of peripheral blood in human subjects was lower in patients with sepsis than controls (P < 0.0001). By studying leukocyte subsets in a subgroup of 13 patients, we showed that this was largely due to an increase in the proportion of circulating neutrophils, which contained approximately 3-fold less mtDNA than mononuclear leukocytes. However, isolated monocytes (P = 0.041) and lymphocytes (P = 0.021) from septic patients showed clear evidence of mtDNA depletion, which correlated with the APACHE II score (P = 0.015). CONCLUSIONS In severe sepsis much of the apparent whole blood mtDNA depletion is due to a change in the differential leukocyte count. However mtDNA depletion in mononuclear cells occurs in patients with sepsis and correlates with disease severity.
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Affiliation(s)
- Angela Pyle
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Framlington Place, Newcastle, NE2 4HH, UK
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Kudin AP, Zsurka G, Elger CE, Kunz WS. Mitochondrial involvement in temporal lobe epilepsy. Exp Neurol 2009; 218:326-32. [PMID: 19268667 DOI: 10.1016/j.expneurol.2009.02.014] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 02/13/2009] [Accepted: 02/19/2009] [Indexed: 10/21/2022]
Abstract
Mitochondrial dysfunction has been identified as a potential cause of epileptic seizures and therapy-resistant forms of severe epilepsy. Thus, a broad variety of mutation in mitochondrial DNA or nuclear genes leading to the impairment of mitochondrial respiratory chain or of mitochondrial ATP synthesis has been associated with epileptic phenotypes. Additionally, with a variety of different methods impaired mitochondrial function has been reported for the seizure focus of patients with temporal lobe epilepsy and Ammon's horn sclerosis and of animal models of temporal lobe epilepsy. Since mitochondrial oxidative phosphorylation provides the major source of ATP in neurons and mitochondria participate in cellular Ca(2+) homeostasis, their dysfunction strongly affects neuronal excitability and synaptic transmission, which is proposed to be highly relevant for seizure generation. Additionally, mitochondrial dysfunction is known to trigger neuronal cell death, which is a prominent feature of therapy-resistant temporal lobe epilepsy. Therefore, mitochondria have to be considered as promising targets for neuroprotective strategies in epilepsy.
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Affiliation(s)
- Alexei P Kudin
- Department of Epileptology, University Bonn Medical Center, Germany
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