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Hippen M, Zsurka G, Peeva V, Machts J, Schwiecker K, Debska-Vielhaber G, Wiesner RJ, Vielhaber S, Kunz WS. Novel Pathogenic Sequence Variation m.5789T>C Causes NARP Syndrome and Promotes Formation of Deletions of the Mitochondrial Genome. Neurol Genet 2022; 8:e660. [PMID: 35252560 PMCID: PMC8893589 DOI: 10.1212/nxg.0000000000000660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/10/2022] [Indexed: 11/15/2022]
Abstract
Background and Objectives We report the pathogenic sequence variant m.5789T>C in the anticodon stem of the mitochondrial tRNA for cysteine as a novel cause of neuropathy, ataxia, and retinitis pigmentosa (NARP), which is usually associated with pathogenic variants in the MT-ATP6 gene. Methods To address the correlation of oxidative phosphorylation deficiency with mutation loads, we performed genotyping on single laser-dissected skeletal muscle fibers. Stability of the mitochondrial tRNACys was investigated by Northern blotting. Accompanying deletions of the mitochondrial genome were detected by long-range PCR and their breakpoints were determined by sequencing of single-molecule amplicons. Results The sequence variant m.5789T>C, originating from the patient's mother, decreases the stability of the mitochondrial tRNA for cysteine by disrupting the anticodon stem, which subsequently leads to a combined oxidative phosphorylation deficiency. In parallel, we observed a prominent cluster of low-abundance somatic deletions with breakpoints in the immediate vicinity of the m.5789T>C variant. Strikingly, all deletion-carrying mitochondrial DNA (mtDNA) species, in which the corresponding nucleotide position was not removed, harbored the mutant allele, and none carried the wild-type allele. Discussion In addition to providing evidence for the novel association of a tRNA sequence alteration with NARP syndrome, our observations support the hypothesis that single nucleotide changes can lead to increased occurrence of site-specific mtDNA deletions through the formation of an imperfect repeat. This finding might be relevant for understanding mechanisms of deletion generation in the human mitochondrial genome.
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Affiliation(s)
- Marius Hippen
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Gábor Zsurka
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Viktoriya Peeva
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Judith Machts
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Kati Schwiecker
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Grazyna Debska-Vielhaber
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Rudolf J Wiesner
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Stefan Vielhaber
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Wolfram S Kunz
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
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Rotko D, Kudin AP, Zsurka G, Kulawiak B, Szewczyk A, Kunz WS. Molecular and Functional Effects of Loss of Cytochrome c Oxidase Subunit 8A. BIOCHEMISTRY (MOSCOW) 2021; 86:33-43. [PMID: 33705280 DOI: 10.1134/s0006297921010041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this work we studied molecular and functional effects of the loss of the smallest nuclear encoded subunit of cytochrome c oxidase COX8A in fibroblasts from a patient with a homozygous splice site mutation and in CRISPR/Cas9 genome-edited HEK293T cells. In both cellular model systems, between 20 to 30% of the residual enzymatic activity of cytochrome c oxidase (COX) was detectable. In immunoblots of BN-PAGE separated mitochondria from both cellular models almost no monomers and dimers of the fully assembled COX could be visualized. Interestingly, supercomplexes of COX formed with complex III and also with complexes I and III retained considerable immunoreactivity, while nearly no immunoreactivity attributable to subassemblies was found. That indicates that COX lacking subunit 8A is stabilized in supercomplexes, while monomers and dimers are rapidly degraded. With transcriptome analysis by 3'-RNA sequencing we failed to detect in our cellular models of COX8A deficiency transcriptional changes of genes involved in the mitochondrial unfolded protein response (mtUPR) and the integrated stress response (ISR). Thus, our data strongly suggest that the smallest subunit of cytochrome c oxidase COX8A is required for maintenance of the structural stability of COX monomers and dimers.
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Affiliation(s)
- Daria Rotko
- Institute of Experimental Epileptology and Cognition Research, Life & Brain Center, University of Bonn, Venusberg-Campus 1, Bonn, 53127, Germany. .,Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, 02-093, Poland
| | - Alexei P Kudin
- Institute of Experimental Epileptology and Cognition Research, Life & Brain Center, University of Bonn, Venusberg-Campus 1, Bonn, 53127, Germany.
| | - Gábor Zsurka
- Institute of Experimental Epileptology and Cognition Research, Life & Brain Center, University of Bonn, Venusberg-Campus 1, Bonn, 53127, Germany. .,Department of Epileptology, University Bonn Medical Center, Venusberg-Campus 1, Bonn, 53127, Germany
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, 02-093, Poland.
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, 02-093, Poland.
| | - Wolfram S Kunz
- Institute of Experimental Epileptology and Cognition Research, Life & Brain Center, University of Bonn, Venusberg-Campus 1, Bonn, 53127, Germany. .,Department of Epileptology, University Bonn Medical Center, Venusberg-Campus 1, Bonn, 53127, 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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Exercise Training Enhances Platelet Mitochondrial Bioenergetics in Stroke Patients: A Randomized Controlled Trial. J Clin Med 2019; 8:jcm8122186. [PMID: 31835774 PMCID: PMC6947198 DOI: 10.3390/jcm8122186] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 12/27/2022] Open
Abstract
Exercise training (ET) may impact physical fitness by affecting mitochondrial functions. This study aimed to elucidate the effect of ET on aerobic capacity and platelet mitochondrial bioenergetics (MTB) in stroke patients. Among the 30 stroke patients who underwent the traditional rehabilitation program (TRP), 15 were randomly assigned to have ET (50-60% VO2peak for 30 min/day, 5 days/week for 4 weeks), and those remaining received only the TRP (control group). The peak exercise capacity (VO2peak) and platelet MTB, including oxidative phosphorylation (OXPHOS) and the electron transport chain (ETC), were measured through automatic gas analysis and high-resolution respirometry, respectively. The results demonstrated that ET significantly increased the VO2peak (17.7%) and O2 uptake efficiency slope (31.9%) but decreased the ventilation versus CO2 production slope (-7.65%). Patients who underwent ET also had significantly enhanced platelet mitochondrial OXPHOS and ETC by activating the FADH2 (Complex II)-dependent pathway, but depressed plasma myeloperoxidase (-28.4%) and interleukin-6 levels (-29.9%). Moreover, changes in VO2peak levels were positively correlated with changes in platelet OXPHOS and ETC capacities. In conclusion, ET increases the platelet MTB by enhancing Complex II activity in stroke patients. The exercise regimen also enhances aerobic fitness and depresses oxidative stress/pro-inflammatory status in stroke patients.
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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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Cheng L, Li B, Chen X, Su J, Wang H, Yu S, Zheng Q. CTRP9 induces mitochondrial biogenesis and protects high glucose-induced endothelial oxidative damage via AdipoR1 -SIRT1- PGC-1α activation. Biochem Biophys Res Commun 2016; 477:685-691. [DOI: 10.1016/j.bbrc.2016.06.120] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 06/24/2016] [Indexed: 10/21/2022]
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Kikusato M, Muroi H, Uwabe Y, Furukawa K, Toyomizu M. Oleuropein induces mitochondrial biogenesis and decreases reactive oxygen species generation in cultured avian muscle cells, possibly via an up-regulation of peroxisome proliferator-activated receptor γ coactivator-1α. Anim Sci J 2016; 87:1371-1378. [DOI: 10.1111/asj.12559] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 08/19/2015] [Accepted: 08/26/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Motoi Kikusato
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science; Tohoku University; Sendai Miyagi Japan
| | - Hikaru Muroi
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science; Tohoku University; Sendai Miyagi Japan
| | - Yuichiro Uwabe
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science; Tohoku University; Sendai Miyagi Japan
| | - Kyohei Furukawa
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science; Tohoku University; Sendai Miyagi Japan
| | - Masaaki Toyomizu
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science; Tohoku University; Sendai Miyagi Japan
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Hallmann K, Kudin AP, Zsurka G, Kornblum C, Reimann J, Stüve B, Waltz S, Hattingen E, Thiele H, Nürnberg P, Rüb C, Voos W, Kopatz J, Neumann H, Kunz WS. Loss of the smallest subunit of cytochrome c oxidase, COX8A, causes Leigh-like syndrome and epilepsy. ACTA ACUST UNITED AC 2015; 139:338-45. [PMID: 26685157 DOI: 10.1093/brain/awv357] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/21/2015] [Indexed: 11/15/2022]
Abstract
Isolated cytochrome c oxidase (complex IV) deficiency is one of the most frequent respiratory chain defects in humans and is usually caused by mutations in proteins required for assembly of the complex. Mutations in nuclear-encoded structural subunits are very rare. In a patient with Leigh-like syndrome presenting with leukodystrophy and severe epilepsy, we identified a homozygous splice site mutation in COX8A, which codes for the ubiquitously expressed isoform of subunit VIII, the smallest nuclear-encoded subunit of complex IV. The mutation, affecting the last nucleotide of intron 1, leads to aberrant splicing, a frame-shift in the highly conserved exon 2, and decreased amount of the COX8A transcript. The loss of the wild-type COX8A protein severely impairs the stability of the entire cytochrome c oxidase enzyme complex and manifests in isolated complex IV deficiency in skeletal muscle and fibroblasts, similar to the frequent c.845_846delCT mutation in the assembly factor SURF1 gene. Stability and activity of complex IV could be rescued in the patient's fibroblasts by lentiviral expression of wild-type COX8A. Our findings demonstrate that COX8A is indispensable for function of human complex IV and its mutation causes human disease.
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Affiliation(s)
- Kerstin Hallmann
- 1 Department of Epileptology and Life and Brain Centre, University of Bonn, Bonn, Germany
| | - Alexei P Kudin
- 1 Department of Epileptology and Life and Brain Centre, University of Bonn, Bonn, Germany
| | - Gábor Zsurka
- 1 Department of Epileptology and Life and Brain Centre, University of Bonn, Bonn, Germany
| | | | - Jens Reimann
- 2 Department of Neurology, University of Bonn, Bonn, Germany
| | | | | | - Elke Hattingen
- 4 Department of Radiology, Division of Neuroradiology, University of Bonn, Bonn, Germany
| | - Holger Thiele
- 5 Cologne Centre for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Peter Nürnberg
- 5 Cologne Centre for Genomics (CCG), University of Cologne, Cologne, Germany 6 Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany 7 Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Cornelia Rüb
- 8 Institut für Biochemie und Molekularbiologie, University of Bonn, Bonn, Germany
| | - Wolfgang Voos
- 8 Institut für Biochemie und Molekularbiologie, University of Bonn, Bonn, Germany
| | - Jens Kopatz
- 9 Neural Regeneration Group, Institute of Reconstructive Neurobiology, University of Bonn, Bonn, Germany
| | - Harald Neumann
- 9 Neural Regeneration Group, Institute of Reconstructive Neurobiology, University of Bonn, Bonn, Germany
| | - Wolfram S Kunz
- 1 Department of Epileptology and Life and Brain Centre, University of Bonn, Bonn, Germany
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Miles L, Greiner HM, Mangano FT, Horn PS, Leach JL, Miles MV. Cytochrome c oxidase deficit is associated with the seizure onset zone in young patients with focal cortical dysplasia Type II. Metab Brain Dis 2015; 30:1151-60. [PMID: 25957585 DOI: 10.1007/s11011-015-9680-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/04/2015] [Indexed: 12/12/2022]
Abstract
It has been postulated that mitochondrial dysfunction may be an important factor in epileptogenesis of intractable epilepsy. The current study tests the hypothesis that mitochondrial Complex IV (CIV) or cytochrome c oxidase dysfunction is associated with the seizure onset zone (SOZ) in patients with focal cortical dysplasia (FCD). Subjects were selected based on: age <19y; epilepsy surgery between May, 2010 and October, 2011; pathological diagnosis of isolated focal cortical dysplasia Type I (FCDI) or Type II (FCDII); and sufficient residual cortical tissue to conduct analysis of electron transport chain complex (ETC) activity in SOZ and adjacent cortical regions. In this retrospective study, patients were identified who had sufficient unfixed, frozen brain tissue for biochemical analysis in tissue homogenates. Specimens were subtyped using ILAE classification for FCD, and excluded if diagnosed with FCD Type III or dual pathology. Analysis of ETC activity in resected tissues was conducted independently and without knowledge of the identity, diagnosis, or clinical status of individual subjects. Seventeen patients met the inclusion criteria, including 6 FCDI and 11 FCDII. Comparison of adjacent cortical resections showed decreased CIV activity in the SOZ of the FCDII group (P = 0.003), but no significant CIV difference in adjacent tissues of the FCDI group. Because of the importance of CIV as the terminal and rate-limiting complex in the mitochondrial electron transport chain, these authors conclude that 1) a deficit of CIV is associated with the SOZ of patients with FCDII; 2) CIV deficiency may contribute to the spectrum of FCD neuropathology; and 3) further investigation of CIV in FCD may lead to the discovery of new targets for neuroprotective therapies for patients with intractable epilepsy.
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Affiliation(s)
- Lili Miles
- Division of Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229, USA,
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Caro AA, Bell M, Ejiofor S, Zurcher G, Petersen DR, Ronis MJJ. N-acetylcysteine inhibits the up-regulation of mitochondrial biogenesis genes in livers from rats fed ethanol chronically. Alcohol Clin Exp Res 2015; 38:2896-906. [PMID: 25581647 DOI: 10.1111/acer.12576] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 09/06/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND Chronic ethanol (EtOH) administration to experimental animals induces hepatic oxidative stress and up-regulates mitochondrial biogenesis. The mechanisms by which chronic EtOH up-regulates mitochondrial biogenesis have not been fully explored. In this work, we hypothesized that oxidative stress is a factor that triggers mitochondrial biogenesis after chronic EtOH feeding. If our hypothesis is correct, co-administration of antioxidants should prevent up-regulation of mitochondrial biogenesis genes. METHODS Rats were fed an EtOH-containing diet intragastrically by total enteral nutrition for 150 days, in the absence or presence of the antioxidant N-acetylcysteine (NAC) at 1.7 g/kg/d; control rats were administered isocaloric diets where carbohydrates substituted for EtOH calories. RESULTS EtOH administration significantly increased hepatic oxidative stress, evidenced as decreased liver total glutathione and reduced glutathione/glutathione disulfide ratio. These effects were inhibited by co-administration of EtOH and NAC. Chronic EtOH increased the expression of mitochondrial biogenesis genes including peroxisome proliferator-activated receptor gamma-coactivator-1 alpha and mitochondrial transcription factor A, and mitochondrial DNA; co-administration of EtOH and NAC prevented these effects. Chronic EtOH administration was associated with decreased mitochondrial mass, inactivation and depletion of mitochondrial complex I and complex IV, and increased hepatic mitochondrial oxidative damage, effects that were not prevented by NAC. CONCLUSIONS These results suggest that oxidative stress caused by chronic EtOH triggered the up-regulation of mitochondrial biogenesis genes in rat liver, because an antioxidant such as NAC prevented both effects. Because NAC did not prevent liver mitochondrial oxidative damage, extra-mitochondrial effects of reactive oxygen species may regulate mitochondrial biogenesis. In spite of the induction of hepatic mitochondrial biogenesis genes by chronic EtOH, mitochondrial mass and function decreased probably in association with mitochondrial oxidative damage. These results also predict that the effectiveness of NAC as an antioxidant therapy for chronic alcoholism will be limited by its limited antioxidant effects in mitochondria, and its inhibitory effect on mitochondrial biogenesis.
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Affiliation(s)
- Andres A Caro
- Chemistry Department , Hendrix College, Conway, Arkansas
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11
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Papanikolaou X, Johnson S, Garg T, Tian E, Tytarenko R, Zhang Q, Stein C, Barlogie B, Epstein J, Heuck C. Artesunate overcomes drug resistance in multiple myeloma by inducing mitochondrial stress and non-caspase apoptosis. Oncotarget 2015; 5:4118-28. [PMID: 24948357 PMCID: PMC4147310 DOI: 10.18632/oncotarget.1847] [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] [Indexed: 12/24/2022] Open
Abstract
Although novel drugs have contributed immensely to improving outcomes of patients with multiple myeloma (MM), many patients develop drug resistance and ultimately succumb to MM. Here, we show that artesunate, an anti-malarial drug, reliably induces cell death in vitro in naïve as well as drug-resistant MM cells at concentrations shown to be safe in humans. Artesunate induced apoptosis predominantly through the non-caspase mediated pathway by primarily targeting mitochondria and causing outer mitochondrial membrane permeabilization that led to cytosolic and subsequent nuclear translocation of mitochondrial proteins apoptosis inducing factor (AIF) and endonuclease G (EndoG). Nuclear translocation of AIF and EndoG was accompanied by low levels of reactive oxygen species (ROS) and increased mitochondrial production of superoxide. These effects were present before apoptosis was evident and were related to intracellular levels of bivalent iron (Fe+2). Artesunate's unique mechanism probably was at least partially responsible for, its ability to act synergistically with multiple anti-myeloma agents. Our findings suggest that artesunate acts through iron to affect the mitochondria and induce low ROS and non-caspase-mediated apoptosis. Its potency, toxicity profile, and synergism with other drugs make it an intriguing new candidate for MM treatment.
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Affiliation(s)
- Xenofon Papanikolaou
- Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, Little Rock, AR
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12
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Terrill JR, Boyatzis A, Grounds MD, Arthur PG. Treatment with the cysteine precursor l-2-oxothiazolidine-4-carboxylate (OTC) implicates taurine deficiency in severity of dystropathology in mdx mice. Int J Biochem Cell Biol 2013; 45:2097-108. [PMID: 23892094 DOI: 10.1016/j.biocel.2013.07.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 06/28/2013] [Accepted: 07/09/2013] [Indexed: 01/29/2023]
Abstract
Oxidative stress has been implicated in the pathology of the lethal skeletal muscle disease Duchenne muscular dystrophy (DMD), and various antioxidants have been investigated as a potential therapy. Recently, treatment of the mdx mouse model for DMD with the antioxidant and cysteine and glutathione (GSH) precursor n-acetylcysteine (NAC) was shown to decrease protein thiol oxidation and improve muscle pathology and ex vivo muscle strength. This study further investigates the mechanism for the benefits of NAC on dystrophic muscle by administering l-2-oxothiazolidine-4-carboxylate (OTC) which also upregulates intracellular cysteine and GSH, but does not directly function as an antioxidant. We observed that OTC, like NAC, decreases protein thiol oxidation, decreases pathology and increases strength, suggesting that the both NAC and OTC function via increasing cysteine and GSH content of dystrophic muscle. We demonstrate that mdx muscle is not deficient in either cysteine or GSH and that these are not increased by OTC treatment. However, we show that dystrophic muscle of 12 week old mdx mice is deficient in taurine, a by-product of disposal of excess cysteine, a deficiency that is ameliorated by OTC treatment. These data suggest that in dystrophic muscles, apart from the strong association of increased oxidative stress and protein thiol oxidation with dystropathology, another major issue is an insufficiency in taurine that can be corrected by increasing the availability of cysteine. This study provides new insight into the molecular mechanism underlying the benefits of NAC in muscular dystrophy and supports the use of OTC as an alternative drug for potential clinical applications to DMD.
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Affiliation(s)
- Jessica R Terrill
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Perth, Western Australia, Australia.
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13
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Arai T, Tanaka M, Kawakami H. Porphyrin-containing electrospun nanofibers: positional control of porphyrin molecules in nanofibers and their catalytic application. ACS APPLIED MATERIALS & INTERFACES 2012; 4:5453-5457. [PMID: 23020508 DOI: 10.1021/am3013664] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Polyacrylonitrile nanofibers containing a series of porphyrin molecules were prepared by an electrospinning method. We first succeeded in controlling the position of porphyrin molecules in the nanofibers by considering porphyrin characteristics and the electrospinning conditions. It was concluded that positive charge of cationic porphyrin, TMPyP, and higher applied voltages were effective to locate the porphyrin molecules on the polymer nanofiber surfaces because of the electrostatic repulsion among the molecules during the electrospinning process. The polymer nanofibers with cationic manganese-porphyrin (Mn-TMPyP) on their surface repeatedly showed superoxide dismutase (SOD) activity, which is a catalytic activity to work as antioxidant in various biochemical fields. The positional control of functional molecules in nanofibers demonstrated a new possibility of nanofiber applications.
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Affiliation(s)
- Takuma Arai
- Department of Applied Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
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14
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Baldwin KM, Joanisse DR, Haddad F, Goldsmith RL, Gallagher D, Pavlovich KH, Shamoon EL, Leibel RL, Rosenbaum M. Effects of weight loss and leptin on skeletal muscle in human subjects. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1259-66. [PMID: 21917907 PMCID: PMC3213951 DOI: 10.1152/ajpregu.00397.2011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 09/06/2011] [Indexed: 01/12/2023]
Abstract
Maintenance of a 10% or greater reduced body weight results in decreases in the energy cost of low levels of physical activity beyond those attributable to the altered body weight. These changes in nonresting energy expenditure are due mainly to increased skeletal muscle work efficiency following weight loss and are reversed by the administration of the adipocyte-derived hormone leptin. We have also shown previously that the maintenance of a reduced weight is accompanied by a decrease in ratio of glycolytic (phosphofructokinase) to oxidative (cytochrome c oxidase) activity in vastus lateralis muscle that would suggest an increase in the relative expression of the myosin heavy chain I (MHC I) isoform. We performed analyses of vastus lateralis muscle needle biopsy samples to determine whether maintenance of an altered body weight was associated with changes in skeletal muscle metabolic properties as well as mRNA expression of different isoforms of the MHC and sarcoplasmic endoplasmic reticular Ca(2+)-dependent ATPase (SERCA) in subjects studied before weight loss and then again after losing 10% of their initial weight and receiving twice daily injections of either placebo or replacement leptin in a single blind crossover design. We found that the maintenance of a reduced body weight was associated with significant increases in the relative gene expression of MHC I mRNA that was reversed by the administration of leptin as well as an increase in the expression of SERCA2 that was not significantly affected by leptin. Leptin administration also resulted in a significant increase in the expression of the less MHC IIx isoform compared with subjects receiving placebo. These findings are consistent with the leptin-reversible increase in skeletal muscle chemomechanical work efficiency and decrease in the ratio of glycolytic/oxidative enzyme activities observed in subjects following dietary weight loss.
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Affiliation(s)
- Kenneth M. Baldwin
- Department of Physiology and Biophysics, School of Medicine, University of California at Irvine, Irvine, California
| | | | - Fadia Haddad
- Department of Physiology and Biophysics, School of Medicine, University of California at Irvine, Irvine, California
| | - Rochelle L. Goldsmith
- Division of Exercise Physiology; Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, New York
| | - Dympna Gallagher
- Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, New York; and
| | - Katherine H. Pavlovich
- Division of Molecular Genetics, Departments of Pediatrics and Medicine, Columbia University, New York, New York
| | - Elisabeth L. Shamoon
- Division of Molecular Genetics, Departments of Pediatrics and Medicine, Columbia University, New York, New York
| | - Rudolph L. Leibel
- Division of Molecular Genetics, Departments of Pediatrics and Medicine, Columbia University, New York, New York
| | - Michael Rosenbaum
- Division of Molecular Genetics, Departments of Pediatrics and Medicine, Columbia University, New York, New York
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15
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Otte DM, Sommersberg B, Kudin A, Guerrero C, Albayram Ö, Filiou MD, Frisch P, Yilmaz Ö, Drews E, Turck CW, Bilkei-Gorzó A, Kunz WS, Beck H, Zimmer A. N-acetyl cysteine treatment rescues cognitive deficits induced by mitochondrial dysfunction in G72/G30 transgenic mice. Neuropsychopharmacology 2011; 36:2233-43. [PMID: 21716263 PMCID: PMC3176560 DOI: 10.1038/npp.2011.109] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Genetic studies have implicated the evolutionary novel, anthropoid primate-specific gene locus G72/G30 in psychiatric diseases. This gene encodes the protein LG72 that has been discussed to function as a putative activator of the peroxisomal enzyme D-amino-acid-oxidase (DAO) and as a mitochondrial protein. We recently generated 'humanized' bacterial artificial chromosome transgenic mice (G72Tg) expressing G72 transcripts in cells throughout the brain. These mice exhibit several behavioral phenotypes related to psychiatric diseases. Here we show that G72Tg mice have a reduced activity of mitochondrial complex I, with a concomitantly increased production of reactive oxygen species. Affected neurons display deficits in short-term plasticity and an impaired capability to sustain synaptic activity. These deficits lead to an impairment in spatial memory, which can be rescued by pharmacological treatment with the glutathione precursor N-acetyl cysteine. Our results implicate LG72-induced mitochondrial and synaptic defects as a possible pathomechanism of psychiatric disorders.
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Affiliation(s)
- David-Marian Otte
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | | | - Alexei Kudin
- Department of Epileptology, University of Bonn, Bonn, Germany
| | - Catalina Guerrero
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | - Önder Albayram
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | | | - Pamela Frisch
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | - Öznur Yilmaz
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | - Eva Drews
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | | | | | - Wolfram S Kunz
- Department of Epileptology, University of Bonn, Bonn, Germany
| | - Heinz Beck
- Department of Epileptology, University of Bonn, Bonn, Germany
| | - Andreas Zimmer
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany,Institute of Molecular Psychiatry, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany, Tel: +49 228 688 5303, Fax: +49 228 688 5301, E-mail:
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Malinska D, Kudin AP, Bejtka M, Kunz WS. Changes in mitochondrial reactive oxygen species synthesis during differentiation of skeletal muscle cells. Mitochondrion 2011; 12:144-8. [PMID: 21782978 DOI: 10.1016/j.mito.2011.06.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 04/15/2011] [Accepted: 06/24/2011] [Indexed: 11/19/2022]
Abstract
Myogenesis is accompanied by an intensive metabolic remodeling. We investigated the mitochondrial reactive oxygen species (ROS) generation at different levels of skeletal muscle differentiation: in C2C12 myoblasts, in C2C12 myotubes and in adult mouse skeletal muscle. Differentiation was accompanied by an increase in mitochondrial content and respiratory chain activity. The detected ROS production levels correlated with mitochondrial content, being the lowest in the myoblasts. Unlike the adult skeletal muscle, myoblast ROS production was significantly stimulated by the complex I inhibitor rotenone. Our results show that mitochondria are an important ROS source in skeletal muscle cells. The substantial changes in mitochondrial ROS synthesis during skeletal muscle differentiation can be explained by intensive bioenergetic remodeling.
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Affiliation(s)
- Dominika Malinska
- Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
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17
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Han YX, Lin YT, Xu JJ, Cao LL, Liu XW, Jiang H, Chi ZF. Status epilepticus stimulates peroxisome proliferator-activated receptor γ coactivator 1-α/mitochondrial antioxidant system pathway by a nitric oxide-dependent mechanism. Neuroscience 2011; 186:128-34. [PMID: 21536107 DOI: 10.1016/j.neuroscience.2011.04.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 12/26/2022]
Abstract
Peroxisome proliferator-activated receptor (PPAR) γ coactivator 1-α (PGC-1α) is a transcriptional coactivator identified as an upstream regulator of lipid catabolism, mitochondrial number and function. PGC-1α protects neurons against oxidative damage by inducing several members of the mitochondrial antioxidant system such as superoxide dismutase 2 (SOD2) and uncoupling protein 2 (UCP2). Its role in seizure-induced oxidative stress has not been studied. Here we showed that pilocarpine-induced status epilepticus (SE) stimulates the PGC-1α/mitochondrial antioxidant system signaling pathway in the rat hippocampus. Because nitric oxide (NO) is the key factor of mitochondrial biogenesis through the transcriptional induction of PGC-1α, we investigated whether NO is involved in activation of the PGC-1α/mitochondrial antioxidant system after SE. Treatment with the NO synthase (NOS) inhibitor N(G)-nitro-l-argininemethyl ester (l-NAME) attenuated the increased expression of the PGC-1α/mitochondrial antioxidant system after SE and enhanced oxidative stress. These results suggest that SE can induce the PGC-1α/mitochondrial antioxidant system signaling pathway, which may represent a protective mechanism against SE-induced oxidative stress. Furthermore, NO may positively regulate the mitochondrial antioxidant system by inducing PGC-1α in pilocarpine-induced SE.
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Affiliation(s)
- Y X Han
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
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18
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Niehusmann P, Surges R, von Wrede RD, Elger CE, Wellmer J, Reimann J, Urbach H, Vielhaber S, Bien CG, Kunz WS. Mitochondrial dysfunction due to Leber's hereditary optic neuropathy as a cause of visual loss during assessment for epilepsy surgery. Epilepsy Behav 2011; 20:38-43. [PMID: 21145289 DOI: 10.1016/j.yebeh.2010.11.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 11/05/2010] [Indexed: 10/18/2022]
Abstract
Assessment for epilepsy surgery may require invasive measures such as implantation of intracranial electrodes or the Wada test. These investigations are commonly well tolerated. However, complications, including visual disturbances of various etiologies, have been reported. Here we describe two patients with pharmacoresistant temporal lobe epilepsy (TLE) who displayed loss of vision in the context of presurgical assessment and in whom mutations associated with Leber's hereditary optic neuropathy (LHON) were detected. Genetic analysis revealed in one patient the frequent mitochondrial G11778A LHON mutation in ND4. In the second patient, the mitochondrial C4640A mutation in ND2 was detected. This rare LHON mutation enhanced the sensitivity of the patient's muscle and brain tissue to amobarbital, a known blocker of the mitochondrial respiratory chain. Mitochondrial dysfunction has been reported in epilepsy. Thus, the presence of LHON mutations can be a rare cause of visual disturbances in patients with epilepsy and may have predisposed to development of epilepsy.
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Affiliation(s)
- Pitt Niehusmann
- Department of Neuropathology, University of Bonn, Bonn, Germany
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19
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Bronnikov GE, Kulagina TP, Aripovsky AV. Dietary supplementation of old rats with hydrogenated peanut oil restores activities of mitochondrial respiratory complexes in skeletal muscles. BIOCHEMISTRY (MOSCOW) 2010; 75:1491-7. [DOI: 10.1134/s0006297910120102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Lemieux H, Tardif JC, Blier PU. Thermal sensitivity of oxidative phosphorylation in rat heart mitochondria: Does pyruvate dehydrogenase dictate the response to temperature? J Therm Biol 2010; 35:105-111. [DOI: 10.1016/j.jtherbio.2009.12.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 11/24/2009] [Accepted: 12/08/2009] [Indexed: 10/20/2022]
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21
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Goldsmith R, Joanisse DR, Gallagher D, Pavlovich K, Shamoon E, Leibel RL, Rosenbaum M. Effects of experimental weight perturbation on skeletal muscle work efficiency, fuel utilization, and biochemistry in human subjects. Am J Physiol Regul Integr Comp Physiol 2010; 298:R79-88. [PMID: 19889869 PMCID: PMC2806213 DOI: 10.1152/ajpregu.00053.2009] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Accepted: 11/02/2009] [Indexed: 11/22/2022]
Abstract
Maintenance of a body weight 10% above or below that "customary" for lean or obese individuals results in respective increases or decreases in the energy expended in low levels of physical activity (nonresting energy expenditure, NREE). These changes are greater than can be accounted for by the altered body weight or composition and are due mainly to altered skeletal muscle work efficiency at low levels of power generation. We performed biochemical analysis of vastus lateralis muscle needle biopsy samples to determine whether maintenance of an altered body weight was associated with changes in skeletal muscle histomorphology. We found that the maintenance of a 10% reduced body weight was associated with significant declines in glycolytic (phosphofructokinase, PFK) enzyme activity and, in particular, in the ratio of glycolytic to oxidative (cytochrome c oxidase, COX) enzyme activity without significant changes in the activities of enzymes relevant to mitochondrial density, respiratory chain activity, or fuel transport; or in skeletal muscle fiber type or glycogen stores. The fractional change in the ratio of PFK/COX activity in subjects following weight loss was significantly correlated with changes in the systemic respiratory exchange ratio (RER) and measures of mechanical efficiency of skeletal muscle at low workloads (pedaling a bicycle to generate 10 or 25 W of power). Thus, predictable changes in systemic skeletal muscle biochemistry accompany the maintenance of an altered body weight and account for a significant portion of the variance in skeletal muscle work efficiency and fuel utilization at reduced body weight.
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Affiliation(s)
- Rochelle Goldsmith
- Department of Medicine, Division of Exercise Physiology, New York, New York, USA
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Abstract
PURPOSE Accumulation of mitochondrial DNA deletions and the resultant impaired oxidative phosphorylation may play a pathogenic role in the mediation of age-related sarcopenia. METHODS Twenty four participants of the New Mexico Aging Process Study were classified as normal lean (n = 15) or sarcopenic (n = 9) based on body composition determined by Dual Energy x-ray Absorptiometry. Complex I and Complex IV activities were measured in the skeletal muscle samples obtained from gastrocnemius muscle. A two-stage nested polymerase chain reaction strategy was used to identify the mitochondrial DNA deletions in the entire mitochondrial genome in the skeletal muscle samples. RESULTS Although Complex I activity was not significantly different (5.5 +/- 0.9 vs. 4.6 +/- 0.7 mU/mg protein, P > 0.05), Complex IV activity was higher in sarcopenic subjects (1.4 +/- 0.3 vs. 1.0 +/- 0.1 mU/mg protein, P < 0.05). Mitochondrial DNA deletions were mostly located in the region of Complex I and spanned from nicotinamide adenine dinucleotide dehydrogenase 1 to nicotinamide adenine dinucleotide dehydrogenase 6. Deletions in the 8,577-10,407 bp and 10,233-11,249 bp regions were associated with a significant decrease in Complex I activity (P < 0.05 and P = 0.02, respectively). Total cumulative deletion, defined as the sum of individual length of deletions in a subject, was comparable in subjects with and without sarcopenia (1760 +/- 726 vs. 1782 +/- 888 bp, P > 0.05). The magnitude of mitochondrial DNA deletion, however, correlated positively with lean body mass (r = 0.43, P < 0.05). CONCLUSION Thus, mitochondrial DNA deletions are common in elderly subjects and are negatively related to Complex I activity. The positive association between mitochondrial DNA deletions and lean body mass needs to be confirmed by studies in a larger study population.
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Breton S, Stewart DT, Blier PU. Role-reversal of gender-associated mitochondrial DNA affects mitochondrial function in Mytilus edulis (Bivalvia: Mytilidae). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2009; 312:108-17. [PMID: 19097171 DOI: 10.1002/jez.b.20251] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Mussel species of the genus Mytilus possess an unusual system of mitochondrial DNA (mtDNA) transmission termed doubly uniparental inheritance. They are characterized by the presence of two highly divergent gender-associated mtDNA genomes (often with>20 and>10% divergences in DNA and amino acid sequences, respectively) that are inherited either maternally (F mtDNA) or paternally (M mtDNA). Females are typically homoplasmic for the F mtDNA and males are heteroplasmic with the F mtDNA being most common in all tissues except the gonad that is dominated by the M mtDNA. Collectively, males are polymorphic for two classes of M mtDNAs known as the "standard male" and "recently masculinized" M types (SM and RM, respectively). The coding portions of the RM mtDNA genome differ from the SM mtDNA by as much as the maternally inherited F mtDNA genome differs from the SM type. Because the SM and RM types exhibit considerable amino acid sequence divergence, we hypothesized that these differences could affect mitochondrial respiratory chain complex enzyme activities. To test this hypothesis, the activity of the major mitochondrial respiratory chain complexes (complexes II, I+III and IV) as well as the activity of citrate synthase were measured on gonad samples from males containing either the SM or RM mtDNA. Our data demonstrate that the mitochondrial subunits encoded by the RM mtDNA are associated with higher enzymatic activities than the gene products of the SM mtDNA.
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Affiliation(s)
- Sophie Breton
- Département de Biologie, Université du Québec à Rimouski, Rimouski, Qué., Canada.
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Clonally Expanded Mitochondrial DNA Mutations in Epileptic Individuals With Mutated DNA Polymerase γ. J Neuropathol Exp Neurol 2008; 67:857-66. [DOI: 10.1097/nen.0b013e3181839b2d] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Unusual presentations of patients with the mitochondrial MERRF mutation A8344G. Clin Neurol Neurosurg 2008; 110:859-63. [DOI: 10.1016/j.clineuro.2008.06.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 06/17/2008] [Accepted: 06/18/2008] [Indexed: 11/21/2022]
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Concerted action of two novel tRNA mtDNA point mutations in chronic progressive external ophthalmoplegia. Biosci Rep 2008; 28:89-96. [PMID: 18384291 DOI: 10.1042/bsr20080004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
CPEO (chronic progressive external ophthalmoplegia) is a common mitochondrial disease phenotype in adults which is due to mtDNA (mitochondrial DNA) point mutations in a subset of patients. Attributing pathogenicity to novel tRNA mtDNA mutations still poses a challenge, particularly when several mtDNA sequence variants are present. In the present study we report a CPEO patient for whom sequencing of the mitochondrial genome revealed three novel tRNA mtDNA mutations: G5835A, del4315A, T1658C in tRNATyr, tRNAIle and tRNAVal genes. In skeletal muscle, the tRNAVal and tRNAIle mutations were homoplasmic, whereas the tRNATyr mutation was heteroplasmic. To address the pathogenic relevance, we performed two types of functional tests: (i) single skeletal muscle fibre analysis comparing G5835A mutation loads and biochemical phenotypes of corresponding fibres, and (ii) Northern-blot analyses of mitochondrial tRNATyr, tRNAIle and tRNAVal. We demonstrated that both the G5835A tRNATyr and del4315A tRNAIle mutation have serious functional consequences. Single-fibre analyses displayed a high threshold of the tRNATyr mutation load for biochemical phenotypic expression at the single-cell level, indicating a rather mild pathogenic effect. In contrast, skeletal muscle tissue showed a severe decrease in respiratory-chain activities, a reduced overall COX (cytochrome c oxidase) staining intensity and abundant COX-negative fibres. Northern-blot analyses showed a dramatic reduction of tRNATyr and tRNAIle levels in muscle, with impaired charging of tRNAIle, whereas tRNAVal levels were only slightly decreased, with amino-acylation unaffected. Our findings suggest that the heteroplasmic tRNATyr and homoplasmic tRNAIle mutation act together, resulting in a concerted effect on the biochemical and histological phenotype. Thus homoplasmic mutations may influence the functional consequences of pathogenic heteroplasmic mtDNA mutations.
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28
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Epilepsia partialis continua and defects in the mitochondrial respiratory chain. Epilepsy Res 2008; 78:1-6. [DOI: 10.1016/j.eplepsyres.2007.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2007] [Revised: 09/30/2007] [Accepted: 10/04/2007] [Indexed: 11/23/2022]
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Bakkman L, Sahlin K, Holmberg HC, Tonkonogi M. Quantitative and qualitative adaptation of human skeletal muscle mitochondria to hypoxic compared with normoxic training at the same relative work rate. Acta Physiol (Oxf) 2007; 190:243-51. [PMID: 17521315 DOI: 10.1111/j.1748-1716.2007.01683.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM To investigate if training during hypoxia (H) improves the adaptation of muscle oxidative function compared with normoxic (N) training performed at the same relative intensity. METHOD Eight untrained volunteers performed one-legged cycle training during 4 weeks in a low-pressure chamber. One leg was trained under N conditions and the other leg under hypobaric hypoxia (526 mmHg) at the same relative intensity as during N (65% of maximal power output, W(max)). Muscle biopsies were taken from vastus lateralis before and after the training period. Muscle samples were analysed for the activities of oxidative enzymes [citrate synthase (CS) and cytochrome c oxidase (COX)] and mitochondrial respiratory function. RESULTS W(max) increased with more than 30% over the training period during both N and H. CS activity increased significantly after training during N conditions (+20.8%, P < 0.05) but remained unchanged after H training (+4.5%, ns) with a significant difference between conditions (P < 0.05 H vs. N). COX activity was not significantly changed by training and was not different between exercise conditions [+14.6 (N) vs. -2.3% (H), ns]. Maximal ADP stimulated respiration (state 3) expressed per weight of muscle tended to increase after N (+31.2%, P < 0.08) but not after H training (+3.2%, ns). No changes were found in state four respiration, respiratory control index, P/O ratio, mitochondrial Ca(2+) resistance and apparent Km for oxygen. CONCLUSION The training-induced increase in muscle oxidative function observed during N was abolished during H. Altitude training may thus be disadvantageous for adaptation of muscle oxidative function.
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Affiliation(s)
- L Bakkman
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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30
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Ruiz-Vela A, Korsmeyer SJ. Proapoptotic histone H1.2 induces CASP-3 and -7 activation by forming a protein complex with CYT c, APAF-1 and CASP-9. FEBS Lett 2007; 581:3422-8. [PMID: 17618626 DOI: 10.1016/j.febslet.2007.06.049] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Revised: 06/05/2007] [Accepted: 06/18/2007] [Indexed: 11/28/2022]
Abstract
Cytochrome c (CYT c) is a protein that employs the caspase recruitment domain (CARD)-containing proteins APAF-1 and CASP-9 to activate effectors CASP-3 and -7. By using affinity labeling techniques and mass spectrometry analysis, we show that histone H1.2 is a regulator of caspases upon UV irradiation. We demonstrated that histone H1.2 forms a protein complex with APAF-1, CASP-9 and CYT c upon UV irradiation. In cell-free systems, we show that histone H1.2 triggers activation of CASP-3 and -7 via APAF-1 and CASP-9. We therefore conclude that upon DNA damage histone H1.2 acts as a positive regulator of apoptosome formation.
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Affiliation(s)
- Antonio Ruiz-Vela
- Howard Hughes Medical Institute, Department of Pathology and Medicine, Harvard Medical School, Boston, MA 02115, USA.
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31
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Hoepken HH, Gispert S, Morales B, Wingerter O, Del Turco D, Mülsch A, Nussbaum RL, Müller K, Dröse S, Brandt U, Deller T, Wirth B, Kudin AP, Kunz WS, Auburger G. Mitochondrial dysfunction, peroxidation damage and changes in glutathione metabolism in PARK6. Neurobiol Dis 2006; 25:401-11. [PMID: 17141510 DOI: 10.1016/j.nbd.2006.10.007] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Revised: 10/03/2006] [Accepted: 10/09/2006] [Indexed: 12/21/2022] Open
Abstract
Oxidative stress and protein aggregation are biochemical hallmarks of Parkinson's disease (PD), a frequent sporadic late-onset degenerative disorder particularly of dopaminergic neurons in the substantia nigra, resulting in impaired spontaneous movement. PARK6 is a rare autosomal-recessively inherited disorder, mimicking the clinical picture of PD with earlier onset and slower progression. Genetic data demonstrated PARK6 to be caused by mutations in the protein PINK1, which is localized to mitochondria and has a serine-threonine kinase domain. To study the effect of PINK1 mutations on oxidative stress, we used primary fibroblasts and immortalized lymphoblasts from three patients homozygous for G309D-PINK1. Oxidative stress was evident from increases in lipid peroxidation and in antioxidant defenses by mitochondrial superoxide dismutase and glutathione. Elevated levels of glutathione reductase and glutathione-S-transferase were also observed. As a putative cause of oxidation, a mild decrease in complex I activity and a trend to superoxide elevation were detectable. These data indicate that PINK1 function is critical to prevent oxidative damage and that peripheral cells may be useful for studies of progression and therapy of PARK6.
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Affiliation(s)
- Hans-Hermann Hoepken
- Section for Molecular Neurogenetics, Clinic for Neurology, University Hospital, Theodor Stern Kai 7, 60590 Frankfurt/M., Germany
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32
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Linnebank M, Lutz H, Jarre E, Vielhaber S, Noelker C, Struys E, Jakobs C, Klockgether T, Evert BO, Kunz WS, Wüllner U. Binding of copper is a mechanism of homocysteine toxicity leading to COX deficiency and apoptosis in primary neurons, PC12 and SHSY-5Y cells. Neurobiol Dis 2006; 23:725-30. [PMID: 16876425 DOI: 10.1016/j.nbd.2006.06.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 06/13/2006] [Accepted: 06/20/2006] [Indexed: 01/09/2023] Open
Abstract
Children with hereditary severe hyperhomocysteinemia present with a variety of neurological impairment, and mild hyperhomocysteinemia has been associated with neurodegeneration in the elderly. The link of hyperhomocysteinemia to neurological dysfunction is unknown. We investigated mitochondrial mechanisms of homocysteine (HCys) neurotoxicity in rat dopaminergic pheochromocytoma cells, human neuroblastoma cells and primary rat cerebellar granule neurons. HCys dose dependently impaired cytochrome c oxidase (COX) activity as well as stability and induced reactive oxygen species and apoptotic cell death. We found that HCys binds the COX cofactor Cu(2+), and Cu(2+) supplementation prior to HCys treatment preserved COX activity and prevented cell death. The Cu(2+) chelating action of HCys and impairement of COX activity represent novel mechanisms of HCys neurotoxicity, which might be preventable by supplementation of Cu(2+).
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Affiliation(s)
- Michael Linnebank
- Department of Neurology, University Hospital Bonn, Sigmund-Freud-Str. 25, 53125 Bonn, Germany.
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Frøyland E, Wibrand F, Almaas R, Dalen I, Lindstad JK, Rootwelt T. Acidosis during reoxygenation has an early detrimental effect on neuronal metabolic activity. Pediatr Res 2005; 57:488-93. [PMID: 15695602 DOI: 10.1203/01.pdr.0000155946.82230.2e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We recently showed that acidosis is protective during hypoxia and detrimental during reoxygenation. We hypothesized that the detrimental effect of acidosis during reoxygenation was due to a negative effect on mitochondrial function. Human postmitotic NT2-N neurons were exposed to 3 h of hypoxia and glucose deprivation and then reoxygenated for 0, 1, 4, 9, or 21 h. The detrimental effect of acidotic reoxygenation on metabolic activity was evident already after 1 h of reoxygenation, when MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] reduction (percentage of normoxic controls) was significantly higher in cells reoxygenated with neutral compared with acidotic medium both after acidotic hypoxia (83+/-26% versus 67+/-27%, p=0.006) and after neutral hypoxia (51+/-12% versus 41+/-7%, p=0.005). Hypoxanthine, a marker of cellular energy failure, increased more with acidotic compared with neutral reoxygenation both after acidotic hypoxia (after 21 h: 7.7+/-2.7 versus 3.1+/-1.9 microM, p<0.001) and after neutral hypoxia (10.4+/-2.6 versus 7.9+/-2.8 microM, p=0.001). During hypoxia and reoxygenation, there was an earlier reduction in the activity of complex IV compared with complexes II+III, and the ratio between these complexes fell during the first hour of reoxygenation. The reduction in complex IV activity was alleviated with acidotic hypoxia. Acidosis during reoxygenation, however, had no effect on the activity of either complex IV or complexes II+III. We conclude that acidosis during hypoxia increases neuronal survival and preserves complex IV activity. Acidosis during reoxygenation has an early detrimental effect on metabolic activity, but this is not mediated through an effect on the mitochondrial complexes IV or II+III.
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Affiliation(s)
- Elisabeth Frøyland
- Department of Pediatric Research, Rikshospitalet University Clinic, Oslo, Norway.
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34
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Kudin AP, Debska-Vielhaber G, Vielhaber S, Elger CE, Kunz WS. The Mechanism of Neuroprotection by Topiramate in an Animal Model of Epilepsy. Epilepsia 2004; 45:1478-87. [PMID: 15571505 DOI: 10.1111/j.0013-9580.2004.13504.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE For the antiepileptic drug (AED) topiramate (TPM), neuroprotective effects have been reported in models of focal cerebral ischemia and experimental status epilepticus, but the putative mechanism of action has remained elusive. METHODS We studied the effects of TPM on mitochondrial function in the pilocarpine rat model of chronic epilepsy and in isolated mitochondria from rat brain. RESULTS TPM treatment in status epilepticus at doses ranging from 20 to 100 mg/kg considerably improved the survival of rats and improved CA1 and CA3 pyramidal cell survival in a dose-dependent manner. This treatment increased the activity of mitochondrial respiratory chain complex I in the CA1 and CA3 pyramidal subfields and resulted in lower seizure frequencies in chronic epileptic rats. In vitro investigations of the action of TPM on isolated rat brain mitochondria ruled out any direct effects of the drug on mitochondrial oxidative phosphorylation but revealed a protective effect on hippocampal mitochondria against an external calcium challenge. This can explain its observed neuroprotective action in the concentration range tested. The in vitro effects of TPM on the calcium handling of isolated brain mitochondria was found to be comparable to the action of cyclosporin A. CONCLUSIONS The neuroprotective action of TPM seems to be directly related to its inhibitory effect on the mitochondrial permeability transition pore.
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Affiliation(s)
- Alexei P Kudin
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany
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35
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Leandri RD, Dulious E, Benbrik E, Jouannet P, De Almeida M. Deficit in cytochrome c oxidase activity induced in rat sperm mitochondria by in vivo exposure to zidovudine. ACTA ACUST UNITED AC 2004; 26:305-9. [PMID: 14511219 DOI: 10.1046/j.1365-2605.2003.00430.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A decreased sperm motility has been reported in men treated with nucleoside analog reverse transcriptase inhibitors (NRTI). Sperm motility is correlated with enzymatic activities of the sperm mitochondrial respiratory chain (MRC), which may be impaired by NRTI. We compared sperm and skeletal muscle MRC and citrate synthase (CS) activities, sperm adenosine triphosphate (ATP) content and sperm motility between rats exposed to zidovudine (AZT) for 10 weeks and controls. Decreased levels of CS-normalized cytochrome c oxidase (COX, the MRC complex IV) activity were observed in the spermatozoa from AZT-treated rats, with no significant decrease in ATP content or motility. In muscle absolute COX activity increased after exposure to AZT but CS-normalized COX activity remained unchanged. These results suggest that exposure to NRTI can induce MRC dysfunction earlier in spermatozoa than in skeletal muscle.
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Affiliation(s)
- Roger Dominique Leandri
- Laboratoire de Biologie de la Reproduction, GREFH, Hôpital Cochin-AP-HP, Université Paris V, Paris, France
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36
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Kudin AP, Bimpong-Buta NYB, Vielhaber S, Elger CE, Kunz WS. Characterization of superoxide-producing sites in isolated brain mitochondria. J Biol Chem 2003; 279:4127-35. [PMID: 14625276 DOI: 10.1074/jbc.m310341200] [Citation(s) in RCA: 390] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial respiratory chain complexes I and III have been shown to produce superoxide but the exact contribution and localization of individual sites have remained unclear. We approached this question investigating the effects of oxygen, substrates, inhibitors, and of the NAD+/NADH redox couple on H2O2 and superoxide production of isolated mitochondria from rat and human brain. Although rat brain mitochondria in the presence of glutamate+malate alone do generate only small amounts of H2O2 (0.04 +/- 0.02 nmol H2O2/min/mg), a substantial production is observed after the addition of the complex I inhibitor rotenone (0.68 +/- 0.25 nmol H2O2/min/mg) or in the presence of the respiratory substrate succinate alone (0.80 +/- 0.27 nmol H2O2/min/mg). The maximal rate of H2O2 generation by respiratory chain complex III observed in the presence of antimycin A was considerably lower (0.14 +/- 0.07 nmol H2O2/min/mg). Similar observations were made for mitochondria isolated from human parahippocampal gyrus. This is an indication that most of the superoxide radicals are produced at complex I and that high rates of production of reactive oxygen species are features of respiratory chain-inhibited mitochondria and of reversed electron flow, respectively. We determined the redox potential of the superoxide production site at complex I to be equal to -295 mV. This and the sensitivity to inhibitors suggest that the site of superoxide generation at complex I is most likely the flavine mononucleotide moiety. Because short-term incubation of rat brain mitochondria with H2O2 induced increased H2O2 production at this site we propose that reactive oxygen species can activate a self-accelerating vicious cycle causing mitochondrial damage and neuronal cell death.
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Affiliation(s)
- Alexei P Kudin
- Department of Epileptology, University Bonn Medical Center, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany
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37
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Vielhaber S, Kudin AP, Kudina TA, Stiller D, Scheich H, Schoenfeld A, Feistner H, Heinze HJ, Elger CE, Kunz WS. Hippocampal N-acetyl aspartate levels do not mirror neuronal cell densities in creatine-supplemented epileptic rats. Eur J Neurosci 2003; 18:2292-300. [PMID: 14622190 DOI: 10.1046/j.1460-9568.2003.02954.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
For neuroprotective therapy of neurodegenerative diseases creatine treatment has gained special interest because creatine has been shown to cross the blood-brain barrier, accumulate in the human brain in vivo and cause delayed neuronal cell death in a large number of animal models. Here, we used the pilocarpine model of temporal lobe epilepsy to determine whether creatine administration is able to attenuate the epilepsy-associated decrease in hippocampal N-acetyl aspartate (NAA) concentrations, impairment of mitochondrial function and neuronal cell loss. In vivo1H-NMR spectroscopy showed, in epileptic rats after creatine administration, higher hippocampal NAA concentrations, suggesting improved neuronal survival. However, in vitro observation of hippocampal slices from creatine-treated epileptic rats revealed a more pronounced loss of pyramidal neurons and decrease in activity of mitochondrial enzymes in hippocampal subfields. This indicates that NAA concentrations measured by in vivo1H-NMR spectroscopy reflect alterations of metabolism rather than neuronal cell densities. Our data indicate an adverse effect of creatine on neuronal survival under conditions of enhanced neuronal activity.
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Mancuso M, Filosto M, Bosetti F, Ceravolo R, Rocchi A, Tognoni G, Manca ML, Solaini G, Siciliano G, Murri L. Decreased platelet cytochrome c oxidase activity is accompanied by increased blood lactate concentration during exercise in patients with Alzheimer disease. Exp Neurol 2003; 182:421-6. [PMID: 12895452 DOI: 10.1016/s0014-4886(03)00092-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Increasing evidence indicates that mitochondrial dysfunction occurs in the central nervous system as well as in the peripheral tissues from Alzheimer's disease (AD) patients. We have recently shown that mitochondrial cytochrome c oxidase (COX) activity is significantly reduced in brain and platelets from AD patients compared to controls. In the present study we investigated whether impaired COX activity could have functional consequences on energy metabolism. Blood lactate concentration was monitored at rest and during incremental exercise in 22 AD patients in whom COX activity in platelets was decreased compared to controls (35.7 +/- 11.4 vs 48.4 +/- 1.4 nmol/min/mg, P < 0.01). In both resting and exercising conditions, blood lactate was significantly higher in AD patients than in controls. Although the magnitude of exercise-related lactate accumulation was not different between the two groups, an anticipated anaerobic lactate threshold during the incremental forearm exercise was found in AD patients (50% of maximal voluntary contraction MVC compared to 60% in controls). COX activity was inversely related to lactate at a significant level for resting condition (r = -0.65) and borderline for anaerobic threshold exercise level. These results support the hypothesis of a systemic impairment of the mitochondrial function in AD and indicate that decreased COX activity could have functional consequences on metabolism.
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Affiliation(s)
- Michelangelo Mancuso
- Department of Neurosciences, Neurological Clinics, University of Pisa, Via Roma 67, 56126, Pisa, Italy.
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Reimann J, Kunz WS, Vielhaber S, Kappes-Horn K, Schröder R. Mitochondrial dysfunction in myofibrillar myopathy. Neuropathol Appl Neurobiol 2003; 29:45-51. [PMID: 12581339 DOI: 10.1046/j.1365-2990.2003.00428.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
'Myofibrillar myopathy' defines a myopathic condition with focal myofibrillar destruction and accumulation of degraded myofibrillar elements. Despite the fact that a number of mutations in different genes as well as cytotoxic agents lead to the disease, abnormal accumulation of desmin is a typical, common feature. Pathological changes of mitochondrial morphology and function have been observed in animal models with intermediate filament pathology. Therefore, in the present study we tested for mitochondrial pathology in skeletal muscle of five patients with the pathohistological diagnosis of myofibrillar myopathy. Screening for large-scale mtDNA deletions and the frequent MERRF (myoclonic epilepsy; ragged red fibres) and MELAS (mitochondrial encephalomyopathy; lactic acidosis; stroke) point mutations was negative in all patients. Histologically, all muscle biopsies showed nonspecific abnormalities of the oxidative/mitochondrial enzyme stainings (histochemistry for reduced nicotinamide adenine dinucleotide, succinic dehydrogenase, cytochrome c oxidase), only one of them had ragged red fibres and a significant number of cytochrome c oxidase-negative fibres. Upon biochemical investigation, four of our patients showed pathologically low respiratory chain complex I activities. Only one of our patients had a pathologically low complex IV activity, while the measurements of the others were within low normal range. The single patient with pathological values for both complex I and IV was the one with the clear histological hallmarks (ragged red and cytochrome c oxidase-negative fibres) of mitochondrial pathology. She also was the only patient with clinical signs hinting at a mitochondrial disorder. Together with data from observations in desmin- and plectin-deficient mice, our results support the view that desmin intermediate filament pathology in these cases is closely linked to mitochondrial dysfunction in skeletal muscle.
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Affiliation(s)
- Jens Reimann
- Department of Neurology, University of Bonn, Germany.
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40
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Vielhaber S, Varlamov DA, Kudina TA, Schröder R, Kappes-Horn K, Elger CE, Seibel M, Seibel P, Kunz WS. Expression pattern of mitochondrial respiratory chain enzymes in skeletal muscle of patients harboring the A3243G point mutation or large-scale deletions of mitochondrial DNA. J Neuropathol Exp Neurol 2002; 61:885-95. [PMID: 12387454 DOI: 10.1093/jnen/61.10.885] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To assess the detailed expression pattern of mitochondrial-encoded proteins in skeletal muscle of patients with mitochondrial diseases we performed determinations of cytochrome content and enzyme activities of respiratory chain complexes of 12 patients harboring large-scale deletions and of 10 patients harboring the A3243G mutation. For large-scale deletions we observed a mutation gene dose-dependent linear decline of cytochrome aa3 content, cytochrome c oxidase (COX) activity, and complex I activity. The content of cytochromes b and the complex III activity was either not affected or only weakly affected by the deletion mutation and did not correlate to the degree of heteroplasmy. In contrast, in skeletal muscle harboring the A3243G mutation all investigated enzymes containing mitochondrial-encoded subunits were equally affected by the mutation, but we observed milder enzyme deficiencies at a comparable mutation gene dose. The results of single fiber analysis of selected biopsies supported these findings but revealed differences in the distribution of COX deficiency. Whereas predominantly type I fibers were affected in A3243G and deletion CPEO biopsies, we observed in MELAS and KSS biopsies higher quantities of COX-deficient type 2 fibers. Our findings indicate different pathomechanisms of deletion and A3243G mutations.
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Affiliation(s)
- Stefan Vielhaber
- Department of Epileptology, University Bonn Medical Center, Germany
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41
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Schröder R, Kunz WS, Rouan F, Pfendner E, Tolksdorf K, Kappes-Horn K, Altenschmidt-Mehring M, Knoblich R, van der Ven PFM, Reimann J, Fürst DO, Blümcke I, Vielhaber S, Zillikens D, Eming S, Klockgether T, Uitto J, Wiche G, Rolfs A. Disorganization of the desmin cytoskeleton and mitochondrial dysfunction in plectin-related epidermolysis bullosa simplex with muscular dystrophy. J Neuropathol Exp Neurol 2002; 61:520-30. [PMID: 12071635 DOI: 10.1093/jnen/61.6.520] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mutations of the human plectin gene (Plec1) cause autosomal recessive epidermolysis bullosa simplex with muscular dystrophy (EBS-MD). Here, we report on molecular mechanisms leading to severe dystrophic muscle alterations in EBS-MD. Analysis of a 25-yr-old EBS-MD patient carrying a novel homozygous 16-bp insertion mutation (13803ins16/13803ins16) close to the intermediate filament (IF) binding site of plectin showed severe disorganization of the myogenic IF cytoskeleton. Intermyofibrillar and subsarcolemmal accumulations of assembled but highly unordered desmin filaments may be attributed to impaired desmin binding capability of the mutant plectin. This IF pathology was also associated with severe mitochondrial dysfunction, suggesting that the muscle pathology of EBS-MD caused by IF disorganization leads not only to defects in mechanical force transduction but also to metabolic dysfunction. Beyond EBS-MD, our data may contribute to the understanding of other myopathies characterized by sarcoplasmic IF accumulations such as desminopathies or alpha-B-crystallinopathies.
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Affiliation(s)
- Rolf Schröder
- Department of Neurology, University of Bonn, Germany
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Abstract
The metabolic myopathies are a heterogeneous group of disorders inherited by a variety of modes that include gene defects in both the nuclear and mitochondrial genomes. Many factors impact on the expression of the pathogenic mutations that cause these disorders including genetic background, environmental factors, and coexisting disorders. Molecular technology has greatly improved the ability to make definitive diagnoses in many of the metabolic myopathies in the last decade and particularly has demonstrated that the wide diversity in the severity of mutations contributes to understanding genotype-phenotype correlations. In some cases, molecular testing obviates the necessity to perform an invasive muscle biopsy. However, it is also clear that the diagnostic yield from molecular testing is incomplete and particularly low among the mitochondrial myopathies as a group, ranging from approximately 6% to 19% in well-classified high-risk groups. Therefore, it is often essential to combine clinical, biochemical, histopathologic, and molecular data for each patient in order to arrive at a definitive diagnosis. The approach to the laboratory diagnosis of metabolic myopathies is described emphasizing both noninvasive and invasive testing, highlighting the molecular methodologies with the benefits and disadvantages of each technology, and documenting how to determine whether patients have coexisting disorders.
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Affiliation(s)
- Georgirene D Vladutiu
- Departments of Pediatrics, Neurology, and Pathology, Division of Genetics, School of Medicine & Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
- Department of Pediatrics, The Children's Hospital of Buffalo, 936 Delaware Avenue, Buffalo, New York, 14209, USA
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Kudin AP, Kudina TA, Seyfried J, Vielhaber S, Beck H, Elger CE, Kunz WS. Seizure-dependent modulation of mitochondrial oxidative phosphorylation in rat hippocampus. Eur J Neurosci 2002; 15:1105-14. [PMID: 11982622 DOI: 10.1046/j.1460-9568.2002.01947.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mitochondrial function is a key determinant of both excitability and viability of neurons. Here, we demonstrate seizure-dependent changes in mitochondrial oxidative phosphorylation in the epileptic rat hippocampus. The intense pathological neuronal activity in pilocarpine-treated rats exhibiting spontaneous seizures resulted in a selective decline of the activities of NADH-CoQ oxidoreductase (complex I of the respiratory chain) and cytochrome c oxidase (complex IV of respiratory chain) in the CA3 and CA1 hippocampal pyramidal subfields. In line with these findings, high-resolution respirometry revealed an increased flux control of complex I on respiration in the CA1 and CA3 subfields and decreased maximal respiration rates in the more severely affected CA3 subfield. Imaging of mitochondrial membrane potential using rhodamine 123 showed a lowered mitochondrial membrane potential in both pyramidal subfields. In contrast to the CA1 and CA3 subfields, mitochondrial oxidative phosphorylation was unaltered in the dentate gyrus and the parahippocampal gyrus. The changes of oxidative phosphorylation in the epileptic rat hippocampus cannot be attributed to oxidative enzyme modifications but are very likely related to a decrease in mitochondrial DNA copy number as shown in the more severely affected CA3 subfield and in cultured PC12 cells partially depleted of mitochondrial DNA. Thus, our results demonstrate that seizure activity downregulates the expression of mitochondrial-encoded enzymes of oxidative phosphorylation. This mechanism could be invoked during diverse forms of pathological neuronal activity and could severely affect both excitability and viability of hippocampal pyramidal neurons.
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Affiliation(s)
- Alexei P Kudin
- Department of Epileptology, University of Bonn Medical Centre, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany
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44
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Vielhaber S, Kaufmann J, Kanowski M, Sailer M, Feistner H, Tempelmann C, Elger CE, Heinze HJ, Kunz WS. Effect of creatine supplementation on metabolite levels in ALS motor cortices. Exp Neurol 2001; 172:377-82. [PMID: 11716561 DOI: 10.1006/exnr.2001.7797] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondrial pathology is an early observation in motor neurons and skeletal muscle of patients with amyotrophic lateral sclerosis (ALS). To clarify the relevance of this finding, we determined the effects of a 1-month oral administration of creatine on (1)H NMR-visible metabolites in the motor cortices of 15 controls and 15 patients with sporadic ALS, most of whom had mitochondrial pathology in skeletal muscle. In the motor cortex of the ALS group the N-acetylaspartate (NAA)/creatine (Cr(t)) metabolite ratio was lower than in our control group, indicating NAA loss. Upon creatine supplementation we observed in the controls a decline in the NAA/Cr(t), NAA/choline (Cho), glutamate + glutamine (Glx)/Cr(t), and Glx/Cho metabolite ratios. In contrast, in the ALS patient group the NAA/Cr(t) and the NAA/Cho metabolite ratios remained unchanged, while the Glx/Cr(t) and Glx/Cho metabolite ratios decreased. These data are compatible with the interpretation that creatine supplementation causes an increase in the diminished NAA levels in ALS motor cortex as well as an increase of choline levels in both ALS and control motor cortices. Because NAA is synthesized by mitochondria in an energy-dependent manner and the NAA/Cho metabolite ratios in the ALS motor cortices were found to be correlated to the degree of mitochondrial pathology in ALS skeletal muscle, our results can be explained by a deficiency of enzymes of mitochondrial respiratory chain in the ALS motor cortex which might affect motor neuron survival.
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Affiliation(s)
- S Vielhaber
- Department of Neurology II, University of Magdeburg Medical Center, Leipziger Strasse 44, Magdeburg, Germany
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Vielhaber S, Schröder R, Winkler K, Weis S, Sailer M, Feistner H, Heinze HJ, Schröder JM, Kunz WS. Defective mitochondrial oxidative phosphorylation in myopathies with tubular aggregates originating from sarcoplasmic reticulum. J Neuropathol Exp Neurol 2001; 60:1032-40. [PMID: 11706933 DOI: 10.1093/jnen/60.11.1032] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abnormalities of the sarcotubular system presenting as tubular aggregates (TAs) have been described in a variety of neuromuscular disorders. Here, we report on immunohistochemical and biochemical findings in 7 patients (2 familial and 5 sporadic cases) suffering from myopathies with TAs. In muscle biopsy specimens from 5 of the 7 patients, TAs were immunopositive for the ryanodine receptor (RYR 1) of the sarcoplasmic reticulum (SR), the SR Ca2+ pump (SERCA2-ATPase), and the intraluminal SR Ca2+ binding protein calsequestrin, indicating an SR origin of these aggregates. Furthermore, these 5 cases showed decreased respiratory chain enzyme activities (NADH:CoQ oxidoreductase. complex I and cytochrome c oxidase [COX], complex IV), while the remaining 2 patients exhibited normal values. Our findings indicate a functional link between mitochondrial dysfunction and the presence of TAs originating from the sarcoplasmic reticulum.
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Affiliation(s)
- S Vielhaber
- Department of Neurology, Otto-von-Guericke-University Magdeburg, Germany
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46
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Jaksch M, Kleinle S, Scharfe C, Klopstock T, Pongratz D, Müller-Höcker J, Gerbitz KD, Liechti-Gallati S, Lochmuller H, Horvath R. Frequency of mitochondrial transfer RNA mutations and deletions in 225 patients presenting with respiratory chain deficiencies. J Med Genet 2001; 38:665-73. [PMID: 11584044 PMCID: PMC1734743 DOI: 10.1136/jmg.38.10.665] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To evaluate the frequency of pathogenic mtDNA transfer RNA mutations and deletions in biochemically demonstrable respiratory chain (RC) deficiencies in paediatric and adult patients. METHODS We screened for deletions and sequenced mitochondrial transfer RNA genes in skeletal muscle DNA from 225 index patients with clinical symptoms suggestive of a mitochondrial disorder and with biochemically demonstrable RC deficiency in skeletal muscle. RESULTS We found pathogenic mitochondrial DNA mutations in 29% of the patients. The detection rate was significantly higher in adults (48%) than in the paediatric group (18%). Only one pathogenic mutation was detected in the neonatal group. In addition, we describe seven novel transfer RNA sequence variations with unknown pathogenic relevance (six homoplasmic and one heteroplasmic) and 13 homoplasmic polymorphisms. One heteroplasmic transfer RNA(Leu(UUR)) A>G mutation at position 3274 is associated with a distinct neurological syndrome. CONCLUSIONS We provide an estimation of the frequency of mitochondrial transfer RNA mutations and deletions in paediatric and adult patients with respiratory chain deficiencies.
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Affiliation(s)
- M Jaksch
- Metabolic Disease Centre Munich-Schwabing and Institute of Clinical Chemistry, Diagnostic Molecular Biology, and Mitochondrial Genetics, Munich, Germany.
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Kunz WS, Kudin AP, Vielhaber S, Bl�mcke I, Zuschratter W, Schramm J, Beck H, Elger CE. Mitochondrial complex I deficiency in the epileptic focus of patients with temporal lobe epilepsy. Ann Neurol 2001. [DOI: 10.1002/1531-8249(200011)48:5<766::aid-ana10>3.0.co;2-m] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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48
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Kunz WS, Kudin A, Vielhaber S, Elger CE, Attardi G, Villani G. Flux control of cytochrome c oxidase in human skeletal muscle. J Biol Chem 2000; 275:27741-5. [PMID: 10869362 DOI: 10.1074/jbc.m004833200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In the present work, by titrating cytochrome c oxidase (COX) with the specific inhibitor KCN, the flux control coefficient and the metabolic reserve capacity of COX have been determined in human saponin-permeabilized muscle fibers. In the presence of the substrates glutamate and malate, a 2.3 +/- 0.2-fold excess capacity of COX was observed in ADP-stimulated human skeletal muscle fibers. This value was found to be dependent on the mitochondrial substrate supply. In the combined presence of glutamate, malate, and succinate, which supported an approximately 1.4-fold higher rate of respiration, only a 1.4 +/- 0.2-fold excess capacity of COX was determined. In agreement with these findings, the flux control of COX increased, in the presence of the three substrates, from 0.27 +/- 0.03 to 0.36 +/- 0.08. These results indicate a tight in vivo control of respiration by COX in human skeletal muscle. This tight control may have significant implications for mitochondrial myopathies. In support of this conclusion, the analysis of skeletal muscle fibers from two patients with chronic progressive external ophthalmoplegia, which carried deletions in 11 and 49% of their mitochondrial DNA, revealed a substantially lowered reserve capacity and increased flux control coefficient of COX, indicating severe rate limitations of oxidative phosphorylation by this enzyme.
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MESH Headings
- Adenosine Diphosphate/metabolism
- Adult
- Blotting, Southern
- Cell Membrane Permeability
- DNA, Mitochondrial/genetics
- Electron Transport Complex IV/antagonists & inhibitors
- Electron Transport Complex IV/genetics
- Electron Transport Complex IV/metabolism
- Humans
- Kinetics
- Middle Aged
- Mitochondria, Muscle/enzymology
- Mitochondrial Myopathies/enzymology
- Muscle Fibers, Skeletal/enzymology
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/pathology
- Ophthalmoplegia, Chronic Progressive External/enzymology
- Ophthalmoplegia, Chronic Progressive External/genetics
- Ophthalmoplegia, Chronic Progressive External/pathology
- Oxygen Consumption/drug effects
- Potassium Cyanide/pharmacology
- Sequence Deletion
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Affiliation(s)
- W S Kunz
- Department of Epileptology, University Bonn Medical Center, Sigmund-Freud-Strasse 25, D-53105 Bonn, Germany.
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