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Hosseinpour S, Razmara E, Heidari M, Rezaei Z, Ashrafi MR, Dehnavi AZ, Kameli R, Bereshneh AH, Vahidnezhad H, Azizimalamiri R, Zamani Z, Pak N, Rasulinezhad M, Mohammadi B, Ghabeli H, Ghafouri M, Mohammadi M, Zamani GR, Badv RS, Saket S, Rabbani B, Mahdieh N, Ahani A, Garshasbi M, Tavasoli AR. A comprehensive study of mutation and phenotypic heterogeneity of childhood mitochondrial leukodystrophies. Brain Dev 2024; 46:167-179. [PMID: 38129218 DOI: 10.1016/j.braindev.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 12/10/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVE Mitochondrial leukodystrophies (MLs) are mainly caused by impairments of the mitochondrial respiratory chains. This study reports the mutation and phenotypic spectrum of a cohort of 41 pediatric patients from 39 distinct families with MLs among 320 patients with a molecular diagnosis of leukodystrophies. METHODS This study summarizes the clinical, imaging, and molecular data of these patients for five years. RESULTS The three most common symptoms were neurologic regression (58.5%), pyramidal signs (58.5%), and extrapyramidal signs (43.9%). Because nuclear DNA mutations are responsible for a high percentage of pediatric MLs, whole exome sequencing was performed on all patients. In total, 39 homozygous variants were detected. Additionally, two previously reported mtDNA variants were identified with different levels of heteroplasmy in two patients. Among 41 mutant alleles, 33 (80.4%) were missense, 4 (9.8%) were frameshift (including 3 deletions and one duplication), and 4 (9.8%) were splicing mutations. Oxidative phosphorylation in 27 cases (65.8%) and mtDNA maintenance pathways in 8 patients (19.5%) were the most commonly affected mitochondrial pathways. In total, 5 novel variants in PDSS1, NDUFB9, FXBL4, SURF1, and NDUSF1 were also detected. In silico analyses showed how each novel variant may contribute to ML pathogenesis. CONCLUSIONS The findings of this study suggest whole-exome sequencing as a strong diagnostic genetic tool to identify the causative variants in pediatric MLs. In comparison between oxidative phosphorylation (OXPHOS) and mtDNA maintenance groups, brain stem and periaqueductal gray matter (PAGM) involvement were more commonly seen in OXPHOS group (P value of 0.002 and 0.009, respectively), and thinning of corpus callosum was observed more frequently in mtDNA maintenance group (P value of 0.042).
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Affiliation(s)
- Sareh Hosseinpour
- Department of Pediatric Neurology, Vali-e-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ehsan Razmara
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Morteza Heidari
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Rezaei
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Reza Ashrafi
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Zare Dehnavi
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, MN 55905, USA
| | - Reyhaneh Kameli
- Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Ali Hosseini Bereshneh
- Prenatal Diagnosis and Genetic Research Center, Dastgheib Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hassan Vahidnezhad
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, USA; Department of Pediatrics, The University of Pennsylvania School of Medicine, Philadelphia, USA
| | - Reza Azizimalamiri
- Department of Pediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Zahra Zamani
- MD, MPH, Community Medicine Specialist, Tehran University of Medical Sciences, Tehran, Iran
| | - Neda Pak
- Department of Radiology, Children's Hospital Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Rasulinezhad
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahram Mohammadi
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Homa Ghabeli
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ghafouri
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Mohammadi
- Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Gholam Reza Zamani
- Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Sasan Saket
- Iranian Child Neurology Center of Excellence, Pediatric Neurology Research Center, Research Institute for Children Health, Mofid Children's and Shohada-e Tajrish Hospitals, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Bahareh Rabbani
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran; Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Ahani
- Mendel Medical Genetics Laboratory, Iran University of Medical Sciences, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Jalal-Al Ahmad Hwy, Tarbiat Modares University, Tehran, Iran.
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic, Division of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Neurology Division, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA.
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2
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McCormick EM, Keller K, Taylor JP, Coffey AJ, Shen L, Krotoski D, Harding B, Gai X, Falk MJ, Zolkipli-Cunningham Z, Rahman S. Expert Panel Curation of 113 Primary Mitochondrial Disease Genes for the Leigh Syndrome Spectrum. Ann Neurol 2023; 94:696-712. [PMID: 37255483 PMCID: PMC10763625 DOI: 10.1002/ana.26716] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/22/2023] [Accepted: 05/23/2023] [Indexed: 06/01/2023]
Abstract
OBJECTIVE Primary mitochondrial diseases (PMDs) are heterogeneous disorders caused by inherited mitochondrial dysfunction. Classically defined neuropathologically as subacute necrotizing encephalomyelopathy, Leigh syndrome spectrum (LSS) is the most frequent manifestation of PMD in children, but may also present in adults. A major challenge for accurate diagnosis of LSS in the genomic medicine era is establishing gene-disease relationships (GDRs) for this syndrome with >100 monogenic causes across both nuclear and mitochondrial genomes. METHODS The Clinical Genome Resource (ClinGen) Mitochondrial Disease Gene Curation Expert Panel (GCEP), comprising 40 international PMD experts, met monthly for 4 years to review GDRs for LSS. The GCEP standardized gene curation for LSS by refining the phenotypic definition, modifying the ClinGen Gene-Disease Clinical Validity Curation Framework to improve interpretation for LSS, and establishing a scoring rubric for LSS. RESULTS The GDR with LSS across the nuclear and mitochondrial genomes was classified as definitive for 31 of 114 GDRs curated (27%), moderate for 38 (33%), limited for 43 (38%), and disputed for 2 (2%). Ninety genes were associated with autosomal recessive inheritance, 16 were maternally inherited, 5 were autosomal dominant, and 3 were X-linked. INTERPRETATION GDRs for LSS were established for genes across both nuclear and mitochondrial genomes. Establishing these GDRs will allow accurate variant interpretation, expedite genetic diagnosis of LSS, and facilitate precision medicine, multisystem organ surveillance, recurrence risk counseling, reproductive choice, natural history studies, and determination of eligibility for interventional clinical trials. ANN NEUROL 2023;94:696-712.
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Affiliation(s)
- Elizabeth M. McCormick
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, Children’s Hospital of Philadelphia (CHOP), Philadelphia, PA, USA
| | - Kierstin Keller
- Center for Mitochondrial and Epigenomic Medicine, Department of Pathology, CHOP, Philadelphia, PA, USA
| | - Julie P. Taylor
- Illumina Clinical Services Laboratory, Illumina Inc., San Diego, CA, USA
| | - Alison J. Coffey
- Illumina Clinical Services Laboratory, Illumina Inc., San Diego, CA, USA
| | - Lishuang Shen
- Center for Personalized Medicine, Department of Pathology & Laboratory Medicine, Children’s Hospital Los Angeles, Los Angeles, CA, USA
| | - Danuta Krotoski
- IDDB/NICHD, National Institutes of Health, Bethesda, MD, USA
| | - Brian Harding
- Departments of Pathology and Lab Medicine (Neuropathology), Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | | | - Xiaowu Gai
- Center for Personalized Medicine, Department of Pathology & Laboratory Medicine, Children’s Hospital Los Angeles, Los Angeles, CA, USA
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Marni J. Falk
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, Children’s Hospital of Philadelphia (CHOP), Philadelphia, PA, USA
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Zarazuela Zolkipli-Cunningham
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, Children’s Hospital of Philadelphia (CHOP), Philadelphia, PA, USA
- University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine, UCL Great Ormond Street Institute of Child Health, and Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
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3
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Meshrkey F, Cabrera Ayuso A, Rao RR, Iyer S. Quantitative analysis of mitochondrial morphologies in human induced pluripotent stem cells for Leigh syndrome. Stem Cell Res 2021; 57:102572. [PMID: 34662843 PMCID: PMC10332439 DOI: 10.1016/j.scr.2021.102572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 10/03/2021] [Accepted: 10/11/2021] [Indexed: 01/19/2023] Open
Abstract
Mitochondria are dynamic organelles with wide range of morphologies contributing to regulating different signaling pathways and several cellular functions. Leigh syndrome (LS) is a classic pediatric mitochondrial disorder characterized by complex and variable clinical pathologies, and primarily affects the nervous system during early development. It is important to understand the differences between mitochondrial morphologies in healthy and diseased states so that focused therapies can target the disease during its early stages. In this study, we performed a comprehensive analysis of mitochondrial dynamics in five patient-derived human induced pluripotent stem cells (hiPSCs) containing different mutations associated with LS. Our results suggest that subtle alterations in mitochondrial morphologies are specific to the mtDNA variant. Three out of the five LS-hiPSCs exhibited characteristics consistent with fused mitochondria. To our knowledge, this is the first comprehensive study that quantifies mitochondrial dynamics in hiPSCs specific to mitochondrial disorders. In addition, we observed an overall decrease in mitochondrial membrane potential in all five LS-hiPSCs. A more thorough analysis of the correlations between mitochondrial dynamics, membrane potential dysfunction caused by mutations in the mtDNA in hiPSCs and differentiated derivatives will aid in identifying unique morphological signatures of various mitochondrial disorders during early stages of embryonic development.
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Affiliation(s)
- Fibi Meshrkey
- Department of Biological Sciences, Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, USA; Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, USA; Department of Histology and Cell Biology, Faculty of Medicine, Alexandria University, Egypt
| | - Ana Cabrera Ayuso
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, USA
| | - Raj R Rao
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, USA; Department of Biomedical Engineering, College of Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Shilpa Iyer
- Department of Biological Sciences, Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, USA; Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, USA.
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4
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Rewiring cell signalling pathways in pathogenic mtDNA mutations. Trends Cell Biol 2021; 32:391-405. [PMID: 34836781 DOI: 10.1016/j.tcb.2021.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/24/2022]
Abstract
Mitochondria generate the energy to sustain cell viability and serve as a hub for cell signalling. Their own genome (mtDNA) encodes genes critical for oxidative phosphorylation. Mutations of mtDNA cause major disease and disability with a wide range of presentations and severity. We review here an emerging body of data suggesting that changes in cell metabolism and signalling pathways in response to the presence of mtDNA mutations play a key role in shaping disease presentation and progression. Understanding the impact of mtDNA mutations on cellular energy homeostasis and signalling pathways seems fundamental to identify novel therapeutic interventions with the potential to improve the prognosis for patients with primary mitochondrial disease.
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5
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Bakare AB, Dean J, Chen Q, Thorat V, Huang Y, LaFramboise T, Lesnefsky EJ, Iyer S. Evaluating the Bioenergetics Health Index Ratio in Leigh Syndrome Fibroblasts to Understand Disease Severity. Int J Mol Sci 2021; 22:ijms221910344. [PMID: 34638685 PMCID: PMC8508996 DOI: 10.3390/ijms221910344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/23/2021] [Accepted: 09/23/2021] [Indexed: 12/21/2022] Open
Abstract
Several pediatric mitochondrial disorders, including Leigh syndrome (LS), impact mitochondrial (mt) genetics, development, and metabolism, leading to complex pathologies and energy failure. The extent to which pathogenic mtDNA variants regulate disease severity in LS is currently not well understood. To better understand this relationship, we computed a glycolytic bioenergetics health index (BHI) for measuring mitochondrial dysfunction in LS patient fibroblast cells harboring varying percentages of pathogenic mutant mtDNA (T8993G, T9185C) exhibiting deficiency in complex V or complex I (T10158C, T12706C). A high percentage (>90%) of pathogenic mtDNA in cells affecting complex V and a low percentage (<39%) of pathogenic mtDNA in cells affecting complex I was quantified. Levels of defective enzyme activities of the electron transport chain correlated with the percentage of pathogenic mtDNA. Subsequent bioenergetics assays showed cell lines relied on both OXPHOS and glycolysis for meeting energy requirements. Results suggest that whereas the precise mechanism of LS has not been elucidated, a multi-pronged approach taking into consideration the specific pathogenic mtDNA variant, glycolytic BHI, and the composite BHI (average ratio of oxphos to glycolysis) can aid in better understanding the factors influencing disease severity in LS.
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Affiliation(s)
- Ajibola B. Bakare
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR 72701, USA;
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA
| | - Joseph Dean
- Cardiology Section Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA 23284, USA; (J.D.); (E.J.L.)
| | - Qun Chen
- Pauley Heart Center, Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23284, USA;
| | - Vedant Thorat
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; (V.T.); (Y.H.); (T.L.)
| | - Yimin Huang
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; (V.T.); (Y.H.); (T.L.)
| | - Thomas LaFramboise
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; (V.T.); (Y.H.); (T.L.)
| | - Edward J. Lesnefsky
- Cardiology Section Medical Service, McGuire Veterans Affairs Medical Center, Richmond, VA 23284, USA; (J.D.); (E.J.L.)
- Pauley Heart Center, Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23284, USA;
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA 23219, USA
| | - Shilpa Iyer
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR 72701, USA;
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA
- Correspondence: ; Tel.: +1-(479)-575-3400
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6
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Bakare AB, Lesnefsky EJ, Iyer S. Leigh Syndrome: A Tale of Two Genomes. Front Physiol 2021; 12:693734. [PMID: 34456746 PMCID: PMC8385445 DOI: 10.3389/fphys.2021.693734] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 07/22/2021] [Indexed: 12/21/2022] Open
Abstract
Leigh syndrome is a rare, complex, and incurable early onset (typically infant or early childhood) mitochondrial disorder with both phenotypic and genetic heterogeneity. The heterogeneous nature of this disorder, based in part on the complexity of mitochondrial genetics, and the significant interactions between the nuclear and mitochondrial genomes has made it particularly challenging to research and develop therapies. This review article discusses some of the advances that have been made in the field to date. While the prognosis is poor with no current substantial treatment options, multiple studies are underway to understand the etiology, pathogenesis, and pathophysiology of Leigh syndrome. With advances in available research tools leading to a better understanding of the mitochondria in health and disease, there is hope for novel treatment options in the future.
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Affiliation(s)
- Ajibola B. Bakare
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Edward J. Lesnefsky
- Division of Cardiology, Pauley Heart Center, Department of Internal Medicine, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
- Department of Physiology/Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
- Department of Biochemistry and Molecular Biology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Shilpa Iyer
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, United States
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7
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Kaur D, Khaniya U, Zhang Y, Gunner MR. Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient. Front Chem 2021; 9:660954. [PMID: 34211960 PMCID: PMC8239185 DOI: 10.3389/fchem.2021.660954] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 05/31/2021] [Indexed: 11/13/2022] Open
Abstract
Biological membranes are barriers to polar molecules, so membrane embedded proteins control the transfers between cellular compartments. Protein controlled transport moves substrates and activates cellular signaling cascades. In addition, the electrochemical gradient across mitochondrial, bacterial and chloroplast membranes, is a key source of stored cellular energy. This is generated by electron, proton and ion transfers through proteins. The gradient is used to fuel ATP synthesis and to drive active transport. Here the mechanisms by which protons move into the buried active sites of Photosystem II (PSII), bacterial RCs (bRCs) and through the proton pumps, Bacteriorhodopsin (bR), Complex I and Cytochrome c oxidase (CcO), are reviewed. These proteins all use water filled proton transfer paths. The proton pumps, that move protons uphill from low to high concentration compartments, also utilize Proton Loading Sites (PLS), that transiently load and unload protons and gates, which block backflow of protons. PLS and gates should be synchronized so PLS proton affinity is high when the gate opens to the side with few protons and low when the path is open to the high concentration side. Proton transfer paths in the proteins we describe have different design features. Linear paths are seen with a unique entry and exit and a relatively straight path between them. Alternatively, paths can be complex with a tangle of possible routes. Likewise, PLS can be a single residue that changes protonation state or a cluster of residues with multiple charge and tautomer states.
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Affiliation(s)
- Divya Kaur
- Department of Chemistry, The Graduate Center, City University of New York, New York, NY, United States.,Department of Physics, City College of New York, New York, NY, United States
| | - Umesh Khaniya
- Department of Physics, City College of New York, New York, NY, United States.,Department of Physics, The Graduate Center, City University of New York, New York, NY, United States
| | - Yingying Zhang
- Department of Physics, City College of New York, New York, NY, United States.,Department of Physics, The Graduate Center, City University of New York, New York, NY, United States
| | - M R Gunner
- Department of Chemistry, The Graduate Center, City University of New York, New York, NY, United States.,Department of Physics, City College of New York, New York, NY, United States.,Department of Physics, The Graduate Center, City University of New York, New York, NY, United States
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8
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Quantifying Mitochondrial Dynamics in Patient Fibroblasts with Multiple Developmental Defects and Mitochondrial Disorders. Int J Mol Sci 2021; 22:ijms22126263. [PMID: 34200828 PMCID: PMC8230542 DOI: 10.3390/ijms22126263] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 05/31/2021] [Accepted: 06/07/2021] [Indexed: 12/11/2022] Open
Abstract
Mitochondria are dynamic organelles that undergo rounds of fission and fusion and exhibit a wide range of morphologies that contribute to the regulation of different signaling pathways and various cellular functions. It is important to understand the differences between mitochondrial structure in health and disease so that therapies can be developed to maintain the homeostatic balance of mitochondrial dynamics. Mitochondrial disorders are multisystemic and characterized by complex and variable clinical pathologies. The dynamics of mitochondria in mitochondrial disorders is thus worthy of investigation. Therefore, in this study, we performed a comprehensive analysis of mitochondrial dynamics in ten patient-derived fibroblasts containing different mutations and deletions associated with various mitochondrial disorders. Our results suggest that the most predominant morphological signature for mitochondria in the diseased state is fragmentation, with eight out of the ten cell lines exhibiting characteristics consistent with fragmented mitochondria. To our knowledge, this is the first comprehensive study that quantifies mitochondrial dynamics in cell lines with a wide array of developmental and mitochondrial disorders. A more thorough analysis of the correlations between mitochondrial dynamics, mitochondrial genome perturbations, and bioenergetic dysfunction will aid in identifying unique morphological signatures of various mitochondrial disorders in the future.
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9
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Blackout in the powerhouse: clinical phenotypes associated with defects in the assembly of OXPHOS complexes and the mitoribosome. Biochem J 2021; 477:4085-4132. [PMID: 33151299 PMCID: PMC7657662 DOI: 10.1042/bcj20190767] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria produce the bulk of the energy used by almost all eukaryotic cells through oxidative phosphorylation (OXPHOS) which occurs on the four complexes of the respiratory chain and the F1–F0 ATPase. Mitochondrial diseases are a heterogenous group of conditions affecting OXPHOS, either directly through mutation of genes encoding subunits of OXPHOS complexes, or indirectly through mutations in genes encoding proteins supporting this process. These include proteins that promote assembly of the OXPHOS complexes, the post-translational modification of subunits, insertion of cofactors or indeed subunit synthesis. The latter is important for all 13 of the proteins encoded by human mitochondrial DNA, which are synthesised on mitochondrial ribosomes. Together the five OXPHOS complexes and the mitochondrial ribosome are comprised of more than 160 subunits and many more proteins support their biogenesis. Mutations in both nuclear and mitochondrial genes encoding these proteins have been reported to cause mitochondrial disease, many leading to defective complex assembly with the severity of the assembly defect reflecting the severity of the disease. This review aims to act as an interface between the clinical and basic research underpinning our knowledge of OXPHOS complex and ribosome assembly, and the dysfunction of this process in mitochondrial disease.
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10
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Wong LJC, Chen T, Schmitt ES, Wang J, Tang S, Landsverk M, Li F, Zhang S, Wang Y, Zhang VW, Craigen WJ. Clinical and laboratory interpretation of mitochondrial mRNA variants. Hum Mutat 2020; 41:1783-1796. [PMID: 32652755 DOI: 10.1002/humu.24082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/29/2020] [Accepted: 07/09/2020] [Indexed: 12/26/2022]
Abstract
Interpretation of mitochondrial protein-encoding (mt-mRNA) variants has been challenging due to mitochondrial characteristics that have not been addressed by American College of Medical Genetics and Genomics guidelines. We developed criteria for the interpretation of mt-mRNA variants via literature review of reported variants, tested and refined these criteria by using our new cases, followed by interpreting 421 novel variants in our clinical database using these verified criteria. A total of 32 of 56 previously reported pathogenic (P) variants had convincing evidence for pathogenicity. These variants are either null variants, well-known disease-causing variants, or have robust functional data or strong phenotypic correlation with heteroplasmy levels. Based on our criteria, 65.7% (730/1,111) of variants of unknown significance (VUS) were reclassified as benign (B) or likely benign (LB), and one variant was scored as likely pathogenic (LP). Furthermore, using our criteria we classified 2, 12, and 23 as P, LP, and LB, respectively, among 421 novel variants. The remaining stayed as VUS (91.2%). Appropriate interpretation of mt-mRNA variants is the basis for clinical diagnosis and genetic counseling. Mutation type, heteroplasmy levels in different tissues of the probands and matrilineal relatives, in silico predictions, population data, as well as functional studies are key points for pathogenicity assessments.
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Affiliation(s)
- Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Baylor Genetics Laboratory, Houston, Texas
| | - Ting Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Eric S Schmitt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Baylor Genetics Laboratory, Houston, Texas
| | - Jing Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Sha Tang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Megan Landsverk
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Fangyuan Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Shulin Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Yue Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Baylor Genetics Laboratory, Houston, Texas
| | - Victor W Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Baylor Genetics Laboratory, Houston, Texas
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11
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Jaberi E, Tresse E, Grønbæk K, Weischenfeldt J, Issazadeh-Navikas S. Identification of unique and shared mitochondrial DNA mutations in neurodegeneration and cancer by single-cell mitochondrial DNA structural variation sequencing (MitoSV-seq). EBioMedicine 2020; 57:102868. [PMID: 32629384 PMCID: PMC7334819 DOI: 10.1016/j.ebiom.2020.102868] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 02/06/2023] Open
Abstract
Background Point mutations and structural variations (SVs) in mitochondrial DNA (mtDNA) contribute to many neurodegenerative diseases. Technical limitations and heteroplasmy, however, have impeded their identification, preventing these changes from being examined in neurons in healthy and disease states. Methods We have developed a high-resolution technique—Mitochondrial DNA Structural Variation Sequencing (MitoSV-seq)—that identifies all types of mtDNA SVs and single-nucleotide variations (SNVs) in single neurons and novel variations that have been undetectable with conventional techniques. Findings Using MitoSV-seq, we discovered SVs/SNVs in dopaminergic neurons in the Ifnar1−/− murine model of Parkinson disease. Further, MitoSV-seq was found to have broad applicability, delivering high-quality, full-length mtDNA sequences in a species-independent manner from human PBMCs, haematological cancers, and tumour cell lines, regardless of heteroplasmy. We characterised several common SVs in haematological cancers (AML and MDS) that were linked to the same mtDNA region, MT-ND5, using only 10 cells, indicating the power of MitoSV-seq in determining single-cancer-cell ontologies. Notably, the MT-ND5 hotspot, shared between all examined cancers and Ifnar1−/− dopaminergic neurons, suggests that its mutations have clinical value as disease biomarkers. Interpretation MitoSV-seq identifies disease-relevant mtDNA mutations in single cells with high resolution, rendering it a potential drug screening platform in neurodegenerative diseases and cancers. Funding The Lundbeck Foundation, Danish Council for Independent Research-Medicine, and European Union Horizon 2020 Research and Innovation Programme.
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Affiliation(s)
- Elham Jaberi
- Neuroinflammation Unit, Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | - Emilie Tresse
- Neuroinflammation Unit, Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | - Kirsten Grønbæk
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark; Department of Hematology, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; The Danish Stem Cell Center (Danstem), University of Copenhagen, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Alle 14, DK-2200 Copenhagen, Denmark
| | - Joachim Weischenfeldt
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | - Shohreh Issazadeh-Navikas
- Neuroinflammation Unit, Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark.
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Singh RK, Saini SK, Prakasam G, Kalairasan P, Bamezai RNK. Role of ectopically expressed mtDNA encoded cytochrome c oxidase subunit I (MT-COI) in tumorigenesis. Mitochondrion 2019; 49:56-65. [PMID: 31299394 DOI: 10.1016/j.mito.2019.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 05/17/2019] [Accepted: 07/03/2019] [Indexed: 11/30/2022]
Abstract
Somatic mutations within mitochondrial DNA (mtDNA) encoded cytochrome c oxidase subunit I (MT-CO1 or MT-COI) are frequent in various cancer types. In addition, perturbation from orchestrated expression of mitochondrial DNA encoded genes is also associated with complex disorders, including cancer. Since codon bias and the mitochondrial translation system restricts functional characterization of over-expressed wild type or mutant mitochondrial DNA encoded genes, the codon optimization and artificial synthesis of entire MT-CO1 allowed us to over-express the wild type and one of its deleterious mutants into the mitochondria of the transfected cells. Ectopically expressed MT-CO1 was observed to efficiently express and localized to mitochondria but showed high level of aggregation under denaturing condition. Over-expression of wild type or mutant variant of MT-CO1 promoted anchorage dependent and independent proliferation potential in in-vitro experiments and introduced the cancer cell metabolic phenotype of high glucose uptake and lactate release. Reactive oxygen species generated in cells over-expressing MT-CO1 variants acted as key effectors mediating differential expression of apoptosis and DNA damage pathway related genes. High ROS generated also down-regulated the expression of global regulators of gene expression, DNMT3A and DNMT3B. The down-regulated expression of DNMTs co-related with differential methylation of the CpG islands in the promoter region of a select set of studied genes, in a manner to promote pro-cancerous phenotype. Apart from assigning the mechanistic role to the MT-CO1 variants and their perturbed expression in cancer development, the present study provides novel insights into the functional role of somatic mutations within MT-CO1 promoting cancer phenotype.
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Affiliation(s)
- Rajnish Kumar Singh
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Sunil Kumar Saini
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Gopinath Prakasam
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ponnuusamy Kalairasan
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rameshwar N K Bamezai
- National Centre of Applied Human Genetics, School of life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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Ni Y, Hagras MA, Konstantopoulou V, Mayr JA, Stuchebrukhov AA, Meierhofer D. Mutations in NDUFS1 Cause Metabolic Reprogramming and Disruption of the Electron Transfer. Cells 2019; 8:cells8101149. [PMID: 31557978 PMCID: PMC6829531 DOI: 10.3390/cells8101149] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 01/07/2023] Open
Abstract
Complex I (CI) is the first enzyme of the mitochondrial respiratory chain and couples the electron transfer with proton pumping. Mutations in genes encoding CI subunits can frequently cause inborn metabolic errors. We applied proteome and metabolome profiling of patient-derived cells harboring pathogenic mutations in two distinct CI genes to elucidate underlying pathomechanisms on the molecular level. Our results indicated that the electron transfer within CI was interrupted in both patients by different mechanisms. We showed that the biallelic mutations in NDUFS1 led to a decreased stability of the entire N-module of CI and disrupted the electron transfer between two iron–sulfur clusters. Strikingly interesting and in contrast to the proteome, metabolome profiling illustrated that the pattern of dysregulated metabolites was almost identical in both patients, such as the inhibitory feedback on the TCA cycle and altered glutathione levels, indicative for reactive oxygen species (ROS) stress. Our findings deciphered pathological mechanisms of CI deficiency to better understand inborn metabolic errors.
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Affiliation(s)
- Yang Ni
- Mass Spectrometry Facility, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany;
- Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
- Present address: Laboratory of Angiogenesis and Vascular Metabolism, VIB-KU Leuven Center for Cancer Biology, 3000 Leuven, Belgium
| | - Muhammad A. Hagras
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA; (M.A.H.); (A.A.S.)
- Present address: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Vassiliki Konstantopoulou
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, 1090 Vienna, Austria;
| | - Johannes A. Mayr
- Department of Pediatrics, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria;
| | - Alexei A. Stuchebrukhov
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA; (M.A.H.); (A.A.S.)
| | - David Meierhofer
- Mass Spectrometry Facility, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany;
- Correspondence: ; Tel.: +49-30-8413-1567
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Pereira C, Souza CFD, Vedolin L, Vairo F, Lorea C, Sobreira C, Nogueira C, Vilarinho L. Leigh Syndrome Due to mtDNA Pathogenic Variants. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2019. [DOI: 10.1590/2326-4594-jiems-2018-0003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
| | | | | | | | - Cláudia Lorea
- Department of Clinical Genomics, USA; Universidade Federal de Pelotas, Brazil
| | | | - Célia Nogueira
- Instituto Nacional de Saúde Doutor Ricardo Jorge, Portugal
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Fiedorczuk K, Sazanov LA. Mammalian Mitochondrial Complex I Structure and Disease-Causing Mutations. Trends Cell Biol 2018; 28:835-867. [PMID: 30055843 DOI: 10.1016/j.tcb.2018.06.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 06/14/2018] [Accepted: 06/22/2018] [Indexed: 12/31/2022]
Abstract
Complex I has an essential role in ATP production by coupling electron transfer from NADH to quinone with translocation of protons across the inner mitochondrial membrane. Isolated complex I deficiency is a frequent cause of mitochondrial inherited diseases. Complex I has also been implicated in cancer, ageing, and neurodegenerative conditions. Until recently, the understanding of complex I deficiency on the molecular level was limited due to the lack of high-resolution structures of the enzyme. However, due to developments in single particle cryo-electron microscopy (cryo-EM), recent studies have reported nearly atomic resolution maps and models of mitochondrial complex I. These structures significantly add to our understanding of complex I mechanism and assembly. The disease-causing mutations are discussed here in their structural context.
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Affiliation(s)
- Karol Fiedorczuk
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria; Present address: The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria.
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16
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Pacheu-Grau D, Rucktäschel R, Deckers M. Mitochondrial dysfunction and its role in tissue-specific cellular stress. Cell Stress 2018; 2:184-199. [PMID: 31225486 PMCID: PMC6551628 DOI: 10.15698/cst2018.07.147] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial bioenergetics require the coordination of two different and independent genomes. Mutations in either genome will affect mitochondrial functionality and produce different sources of cellular stress. Depending on the kind of defect and stress, different tissues and organs will be affected, leading to diverse pathological conditions. There is no curative therapy for mitochondrial diseases, nevertheless, there are strategies described that fight the various stress forms caused by the malfunctioning organelles. Here, we will revise the main kinds of stress generated by mutations in mitochondrial genes and outline several ways of fighting this stress.
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Affiliation(s)
- David Pacheu-Grau
- Department of Cellular Biochemistry, University Medical Center Göttingen, Germany
| | - Robert Rucktäschel
- Department of Cellular Biochemistry, University Medical Center Göttingen, Germany
| | - Markus Deckers
- Department of Cellular Biochemistry, University Medical Center Göttingen, Germany
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17
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A modeling and simulation perspective on the mechanism and function of respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:510-523. [DOI: 10.1016/j.bbabio.2018.04.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/03/2018] [Accepted: 04/10/2018] [Indexed: 12/12/2022]
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Mitochondrial ND5 mutation mediated elevated ROS regulates apoptotic pathway epigenetically in a P53 dependent manner for generating pro-cancerous phenotypes. Mitochondrion 2017; 35:35-43. [PMID: 28502718 DOI: 10.1016/j.mito.2017.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/02/2017] [Accepted: 05/08/2017] [Indexed: 11/23/2022]
Abstract
We have previously observed concomitant events of mutations in mitochondrial and nuclear genes, along with elevated reactive oxygen species (ROS) and differential methylation within the promoters of nuclear genes in tumors and in vitro experiments of tumorigenesis. These observations have made it pertinent to replicate and understand the role of acquired mitochondrial condition in tuning a cell to accomplish a pro-cancerous state. Using a codon optimized vector system for exogenous over-expression and mitochondrial localization; we have characterized here the role of over-expressed wild type mtND5 and one of its non-synonymous somatic mutation, ND5:P265H. The ectopically over-expressed ND5:P265H in mitochondria resulted in a reduced Complex I activity, generation of higher ADP/ATP ratio, reactive oxygen species (ROS) and carbonylation of proteins as compared to mock-transfected cells. Cells over-expressing mtND5 variant produced both peroxide as well as super-oxide ROS; the generation of which was dependent on the functional status of P53; modulating epigenetically the expression of key apoptosis pathway genes. The pro-cancerous phenotypes, of anchorage dependent and independent growth; increased glucose uptake and lactate production, were selectively observed only in P53 non-functional cells over-expressing mutant ND5:P265H. We propose that somatic mutation in mtND5 resulting in down-regulated complex I enzyme activity, elevated ROS and up-regulation of a set of nuclear anti-apoptotic genes epigenetically in the P53 dysfunctional cellular background, has provided a unique understanding of the molecular mechanism of mitochondrial mutation; and the concomitant existence of somatically acquired mitochondrial and nuclear p53 mutations, in cancer progression and promotion.
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19
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In silico analysis for predicting pathogenicity of five unclassified mitochondrial DNA mutations associated with mitochondrial cytopathies' phenotypes. Eur J Med Genet 2017; 60:172-177. [DOI: 10.1016/j.ejmg.2016.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 12/13/2016] [Accepted: 12/21/2016] [Indexed: 11/17/2022]
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20
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Pronicka E, Piekutowska-Abramczuk D, Ciara E, Trubicka J, Rokicki D, Karkucińska-Więckowska A, Pajdowska M, Jurkiewicz E, Halat P, Kosińska J, Pollak A, Rydzanicz M, Stawinski P, Pronicki M, Krajewska-Walasek M, Płoski R. New perspective in diagnostics of mitochondrial disorders: two years' experience with whole-exome sequencing at a national paediatric centre. J Transl Med 2016; 14:174. [PMID: 27290639 PMCID: PMC4903158 DOI: 10.1186/s12967-016-0930-9] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/31/2016] [Indexed: 12/30/2022] Open
Abstract
Background Whole-exome sequencing (WES) has led to an exponential increase in identification of causative variants in mitochondrial disorders (MD). Methods We performed WES in 113 MD suspected patients from Polish paediatric reference centre, in whom routine testing failed to identify a molecular defect. WES was performed using TruSeqExome enrichment, followed by variant prioritization, validation by Sanger sequencing, and segregation with the disease phenotype in the family. Results Likely causative mutations were identified in 67 (59.3 %) patients; these included variants in mtDNA (6 patients) and nDNA: X-linked (9 patients), autosomal dominant (5 patients), and autosomal recessive (47 patients, 11 homozygotes). Novel variants accounted for 50.5 % (50/99) of all detected changes. In 47 patients, changes in 31 MD-related genes (ACAD9, ADCK3, AIFM1, CLPB, COX10, DLD, EARS2, FBXL4, MTATP6, MTFMT, MTND1, MTND3, MTND5, NAXE, NDUFS6, NDUFS7, NDUFV1, OPA1, PARS2, PC, PDHA1, POLG, RARS2, RRM2B, SCO2, SERAC1, SLC19A3, SLC25A12, TAZ, TMEM126B, VARS2) were identified. The ACAD9, CLPB, FBXL4, PDHA1 genes recurred more than twice suggesting higher general/ethnic prevalence. In 19 cases, variants in 18 non-MD related genes (ADAR, CACNA1A, CDKL5, CLN3, CPS1, DMD, DYSF, GBE1, GFAP, HSD17B4, MECP2, MYBPC3, PEX5, PGAP2, PIGN, PRF1, SBDS, SCN2A) were found. The percentage of positive WES results rose gradually with increasing probability of MD according to the Mitochondrial Disease Criteria (MDC) scale (from 36 to 90 % for low and high probability, respectively). The percentage of detected MD-related genes compared with non MD-related genes also grew with the increasing MD likelihood (from 20 to 97 %). Molecular diagnosis was established in 30/47 (63.8 %) neonates and in 17/28 (60.7 %) patients with basal ganglia involvement. Mutations in CLPB, SERAC1, TAZ genes were identified in neonates with 3-methylglutaconic aciduria (3-MGA) as a discriminative feature. New MD-related candidate gene (NDUFB8) is under verification. Conclusions We suggest WES rather than targeted NGS as the method of choice in diagnostics of MD in children, including neonates with 3-MGA aciduria, who died without determination of disease cause and with limited availability of laboratory data. There is a strong correlation between the degree of MD diagnosis by WES and MD likelihood expressed by the MDC scale. Electronic supplementary material The online version of this article (doi:10.1186/s12967-016-0930-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ewa Pronicka
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland. .,Department of Paediatrics, Nutrition and Metabolic Diseases,, The Children's Memorial Health Institute, Warsaw, Poland.
| | | | - Elżbieta Ciara
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Joanna Trubicka
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Dariusz Rokicki
- Department of Paediatrics, Nutrition and Metabolic Diseases,, The Children's Memorial Health Institute, Warsaw, Poland
| | | | - Magdalena Pajdowska
- Department of Biochemistry and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Elżbieta Jurkiewicz
- Department of Radiology, The Children's Memorial Health Institute, Warsaw, Poland
| | - Paulina Halat
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Joanna Kosińska
- Department of Medical Genetics, Warsaw Medical University, Pawińskiego str, 02-106, Warsaw, Poland
| | - Agnieszka Pollak
- Department of Genetics, Institute of Physiology and Pathology of Hearing, Nadarzyn, Poland
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Warsaw Medical University, Pawińskiego str, 02-106, Warsaw, Poland
| | - Piotr Stawinski
- Department of Genetics, Institute of Physiology and Pathology of Hearing, Nadarzyn, Poland
| | - Maciej Pronicki
- Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland
| | | | - Rafał Płoski
- Department of Medical Genetics, Warsaw Medical University, Pawińskiego str, 02-106, Warsaw, Poland.
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Miryounesi M, Fardaei M, Tabei SM, Ghafouri-Fard S. Leigh syndrome associated with a novel mutation in the COX15 gene. J Pediatr Endocrinol Metab 2016; 29:741-4. [PMID: 26959537 DOI: 10.1515/jpem-2015-0396] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 01/04/2016] [Indexed: 11/15/2022]
Abstract
Leigh syndrome (LS) is a subacute necrotizing encephalomyelopathy with a diverse range of symptoms, such as psychomotor delay or regression, weakness, hypotonia, truncal ataxia, intention tremor as well as lactic acidosis in the blood, cerebrospinal fluid or urine. Both nuclear gene defects and mutations of the mitochondrial genome have been detected in these patients. Here we report a 7-year-old girl with hypotonia, tremor, developmental delay and psychomotor regression. However, serum lactate level as well as brain magnetic resonance imaging were normal. Mutational analysis has revealed a novel mutation in exon 4 of COX15 gene (c.415C>G) which results in p.Leu139Val. Previous studies have demonstrated that COX15 mutations are associated with typical LS as well as fatal infantile hypertrophic cardiomyopathy. Consequently, clinical manifestations of COX15 mutations may be significantly different in patients. Such information is of practical importance in genetic counseling.
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Gerards M, Sallevelt SCEH, Smeets HJM. Leigh syndrome: Resolving the clinical and genetic heterogeneity paves the way for treatment options. Mol Genet Metab 2016; 117:300-12. [PMID: 26725255 DOI: 10.1016/j.ymgme.2015.12.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 12/31/2022]
Abstract
Leigh syndrome is a progressive neurodegenerative disorder, affecting 1 in 40,000 live births. Most patients present with symptoms between the ages of three and twelve months, but adult onset Leigh syndrome has also been described. The disease course is characterized by a rapid deterioration of cognitive and motor functions, in most cases resulting in death due to respiratory failure. Despite the high genetic heterogeneity of Leigh syndrome, patients present with identical, symmetrical lesions in the basal ganglia or brainstem on MRI, while additional clinical manifestations and age of onset varies from case to case. To date, mutations in over 60 genes, both nuclear and mitochondrial DNA encoded, have been shown to cause Leigh syndrome, still explaining only half of all cases. In most patients, these mutations directly or indirectly affect the activity of the mitochondrial respiratory chain or pyruvate dehydrogenase complex. Exome sequencing has accelerated the discovery of new genes and pathways involved in Leigh syndrome, providing novel insights into the pathophysiological mechanisms. This is particularly important as no general curative treatment is available for this devastating disorder, although several recent studies imply that early treatment might be beneficial for some patients depending on the gene or process affected. Timely, gene-based personalized treatment may become an important strategy in rare, genetically heterogeneous disorders like Leigh syndrome, stressing the importance of early genetic diagnosis and identification of new genes/pathways. In this review, we provide a comprehensive overview of the most important clinical manifestations and genes/pathways involved in Leigh syndrome, and discuss the current state of therapeutic interventions in patients.
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Affiliation(s)
- Mike Gerards
- Department of Clinical Genetics, Research School GROW, Maastricht University Medical Centre, Maastricht, The Netherlands; Maastricht Center for Systems Biology (MaCSBio), Maastricht University Medical Centre, Maastricht, The Netherlands.
| | - Suzanne C E H Sallevelt
- Department of Clinical Genetics, Research School GROW, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Hubert J M Smeets
- Department of Clinical Genetics, Research School GROW, Maastricht University Medical Centre, Maastricht, The Netherlands
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23
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Lake NJ, Compton AG, Rahman S, Thorburn DR. Leigh syndrome: One disorder, more than 75 monogenic causes. Ann Neurol 2015; 79:190-203. [PMID: 26506407 DOI: 10.1002/ana.24551] [Citation(s) in RCA: 301] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/16/2015] [Accepted: 10/18/2015] [Indexed: 12/19/2022]
Abstract
Leigh syndrome is the most common pediatric presentation of mitochondrial disease. This neurodegenerative disorder is genetically heterogeneous, and to date pathogenic mutations in >75 genes have been identified, encoded by 2 genomes (mitochondrial and nuclear). More than one-third of these disease genes have been characterized in the past 5 years alone, reflecting the significant advances made in understanding its etiological basis. We review the diverse biochemical and genetic etiology of Leigh syndrome and associated clinical, neuroradiological, and metabolic features that can provide clues for diagnosis. We discuss the emergence of genotype-phenotype correlations, insights gleaned into the molecular basis of disease, and available therapeutic options.
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Affiliation(s)
- Nicole J Lake
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Alison G Compton
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine, Institute of Child Health, University College London and Metabolic Unit, Great Ormond Street Hospital, London, United Kingdom
| | - David R Thorburn
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Victorian Clinical Genetic Services, Royal Children's Hospital, Melbourne, Victoria, Australia
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CHEN ZHITING, ZHAO ZHENHUA, YE QINYONG, CHEN YING, PAN XIAODONG, SUN BIN, HUANG HUAPIN, ZHENG AN. Mild clinical manifestation and unusual recovery upon coenzyme Q10 treatment in the first Chinese Leigh syndrome pedigree with mutation m.10197 G>A. Mol Med Rep 2014; 11:1956-62. [DOI: 10.3892/mmr.2014.2911] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 04/01/2014] [Indexed: 11/06/2022] Open
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Ridge PG, Maxwell TJ, Foutz SJ, Bailey MH, Corcoran CD, Tschanz JT, Norton MC, Munger RG, O'Brien E, Kerber RA, Cawthon RM, Kauwe JSK. Mitochondrial genomic variation associated with higher mitochondrial copy number: the Cache County Study on Memory Health and Aging. BMC Bioinformatics 2014; 15 Suppl 7:S6. [PMID: 25077862 PMCID: PMC4110732 DOI: 10.1186/1471-2105-15-s7-s6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background The mitochondria are essential organelles and are the location of cellular respiration, which is responsible for the majority of ATP production. Each cell contains multiple mitochondria, and each mitochondrion contains multiple copies of its own circular genome. The ratio of mitochondrial genomes to nuclear genomes is referred to as mitochondrial copy number. Decreases in mitochondrial copy number are known to occur in many tissues as people age, and in certain diseases. The regulation of mitochondrial copy number by nuclear genes has been studied extensively. While mitochondrial variation has been associated with longevity and some of the diseases known to have reduced mitochondrial copy number, the role that the mitochondrial genome itself has in regulating mitochondrial copy number remains poorly understood. Results We analyzed the complete mitochondrial genomes from 1007 individuals randomly selected from the Cache County Study on Memory Health and Aging utilizing the inferred evolutionary history of the mitochondrial haplotypes present in our dataset to identify sequence variation and mitochondrial haplotypes associated with changes in mitochondrial copy number. Three variants belonging to mitochondrial haplogroups U5A1 and T2 were significantly associated with higher mitochondrial copy number in our dataset. Conclusions We identified three variants associated with higher mitochondrial copy number and suggest several hypotheses for how these variants influence mitochondrial copy number by interacting with known regulators of mitochondrial copy number. Our results are the first to report sequence variation in the mitochondrial genome that causes changes in mitochondrial copy number. The identification of these variants that increase mtDNA copy number has important implications in understanding the pathological processes that underlie these phenotypes.
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Cation transport by the respiratory NADH:quinone oxidoreductase (complex I): facts and hypotheses. Biochem Soc Trans 2014; 41:1280-7. [PMID: 24059520 DOI: 10.1042/bst20130024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The respiratory complex I (electrogenic NADH:quinone oxidoreductase) has been considered to act exclusively as a H+ pump. This was questioned when the search for the NADH-driven respiratory Na+ pump in Klebsiella pneumoniae initiated by Peter Dimroth led to the discovery of a Na+-translocating complex in this enterobacterium. The 3D structures of complex I from different organisms support the idea that the mechanism of cation transport by complex I involves conformational changes of the membrane-bound NuoL, NuoM and NuoN subunits. In vitro methods to follow Na+ transport were compared with in vivo approaches to test whether complex I, or its individual NuoL, NuoM or NuoN subunits, extrude Na+ from the cytoplasm to the periplasm of bacterial host cells. The truncated NuoL subunit of the Escherichia coli complex I which comprises amino acids 1-369 exhibits Na+ transport activity in vitro. This observation, together with an analysis of putative cation channels in NuoL, suggests that there exists in NuoL at least one continuous pathway for cations lined by amino acid residues from transmembrane segments 3, 4, 5, 7 and 8. Finally, we discuss recent studies on Na+ transport by mitochondrial complex I with respect to its putative role in the cycling of Na+ ions across the inner mitochondrial membrane.
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Mourier A, Ruzzenente B, Brandt T, Kühlbrandt W, Larsson NG. Loss of LRPPRC causes ATP synthase deficiency. Hum Mol Genet 2014; 23:2580-92. [PMID: 24399447 PMCID: PMC3990160 DOI: 10.1093/hmg/ddt652] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Defects of the oxidative phosphorylation system, in particular of cytochrome-c oxidase (COX, respiratory chain complex IV), are common causes of Leigh syndrome (LS), which is a rare neurodegenerative disorder with severe progressive neurological symptoms that usually present during infancy or early childhood. The COX-deficient form of LS is commonly caused by mutations in genes encoding COX assembly factors, e.g. SURF1, SCO1, SCO2 or COX10. However, other mutations affecting genes that encode proteins not directly involved in COX assembly can also cause LS. The leucine-rich pentatricopeptide repeat containing protein (LRPPRC) regulates mRNA stability, polyadenylation and coordinates mitochondrial translation. In humans, mutations in Lrpprc cause the French Canadian type of LS. Despite the finding that LRPPRC deficiency affects the stability of most mitochondrial mRNAs, its pathophysiological effect has mainly been attributed to COX deficiency. Surprisingly, we show here that the impaired mitochondrial respiration and reduced ATP production observed in Lrpprc conditional knockout mouse hearts is caused by an ATP synthase deficiency. Furthermore, the appearance of inactive subassembled ATP synthase complexes causes hyperpolarization and increases mitochondrial reactive oxygen species production. Our findings shed important new light on the bioenergetic consequences of the loss of LRPPRC in cardiac mitochondria.
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Affiliation(s)
- Arnaud Mourier
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany and
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Adams G, Mehrabi S, Vatcharapijarn Y, Iyamu OI, Akwe JA, Grizzle WE, Yao X, Aikhionbare FO. Frequencies of mtDNA mutations in primary tissues of colorectal adenopolyps. Front Biosci (Elite Ed) 2013; 5:809-13. [PMID: 23747897 DOI: 10.2741/e661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
To investigate the potential role of mtDNA alterations during the onset of colorectal cancer, the occurrence of mtDNA variants in colorectal adenomatous (Tubular, Tubulovillous, and Villous) polyps, were studied. High resolution endonucleases and PCR-based sequence were applied to examine mtDNA variants in the ND and ATPase genes of 64 primary tissues of colorectal adeno-polyps and their matched normal controls. Forty-two variants were observed and 57% (24/42) were not previously reported in the MITODAT reference. Fifty-eight percent of these variants were germline and homoplasmic transitions. The distribution of observed mtDNA variants includes: 31% (13/42) tubular, 52% (22/42) tubulovillous, 45% (19/42) villous, and 45% (19/42) cancer (including FAP and JVP). Notably, an unreported germline variant in the ATPase 8 gene at nucleotide position (np) G8573A was observed in tubulovillous adenomas tissues. The results suggest that some specific mtDNA variants may serve as a potential biomarker for colorectal adenomatous polyps.
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Affiliation(s)
- Gregory Adams
- Department of Medicine, Morehouse School of Medicine, Atlanta, GA 30310, USA
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Abstract
The progress of molecular genetics helps clinicians to prove or exclude a suspected diagnosis for a vast and yet increasing number of genodermatoses. This leads to precise genetic counselling, prenatal diagnosis and preimplantation genetic haplotyping for many inherited skin conditions. It is also helpful in such occasions as phenocopy, late onset and incomplete penetrance, uniparental disomy, mitochondrial inheritance and pigmentary mosaicism. Molecular methods of two genodermatoses are explained in detail, i.e. genodermatoses with skin fragility and neurofibromatosis type 1.
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Affiliation(s)
- Vesarat Wessagowit
- Molecular Genetics Laboratory, The Institute of Dermatology, Bangkok, Thailand.
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Iommarini L, Calvaruso MA, Kurelac I, Gasparre G, Porcelli AM. Complex I impairment in mitochondrial diseases and cancer: Parallel roads leading to different outcomes. Int J Biochem Cell Biol 2013; 45:47-63. [DOI: 10.1016/j.biocel.2012.05.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/03/2012] [Accepted: 05/24/2012] [Indexed: 02/06/2023]
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Mitochondrial DNA haplogroup Y is associated to Leigh syndrome in Chinese population. Gene 2012; 512:460-3. [PMID: 23111160 DOI: 10.1016/j.gene.2012.10.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/31/2012] [Accepted: 10/09/2012] [Indexed: 11/27/2022]
Abstract
Although Leigh syndrome (LS) is a well characterized clinical mitochondrial disorder; the exact mutation is not found in all cases and it is not clear whether matrilineal background has contributed to this disease. To address this issue, we extensively studied and compared the haplogroup composition of a sample of 171 Chinese LS patients with that of 1597 controls. Our results show that haplogroup Y may increase the risk of LS in Chinese by 2.867 fold (95% CI=1.135-7.240, P=0.020). Haplogroup B5 has also this trend (1.737 fold, 95% CI=0.961-3.139), but with a borderline P-value (P=0.065). Both haplogroups belong to macro-haplogroup N and share a common reverse mutation on nucleotide position 10398 (A10398G). In fact, the combined haplogroup N with 10398G is also associated with an increased risk for LS (OR=1.882, 95% CI=1.134-3.124, P=0.013).
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Analysis of the structural and mechanistic factors in antioxidants that preserve mitochondrial function and confer cytoprotection. Bioorg Med Chem 2012; 20:5188-201. [DOI: 10.1016/j.bmc.2012.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 06/27/2012] [Accepted: 07/04/2012] [Indexed: 12/31/2022]
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Nesbitt V, Morrison PJ, Crushell E, Donnelly DE, Alston CL, He L, McFarland R, Taylor RW. The clinical spectrum of the m.10191T>C mutation in complex I-deficient Leigh syndrome. Dev Med Child Neurol 2012; 54:500-6. [PMID: 22364517 DOI: 10.1111/j.1469-8749.2012.04224.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mitochondrial respiratory chain diseases represent one of the most common inherited neurometabolic disorders of childhood, affecting a minimum of 1 in 7500 live births. The marked clinical, biochemical, and genetic heterogeneity means that accurate genetic counselling relies heavily upon the identification of the underlying causative mutation in the individual and determination of carrier status in the parents. Isolated complex I deficiency is the most common respiratory chain defect observed in children, resulting in organ-specific or multisystem disease, but most often presenting as Leigh syndrome, for which mitochondrial DNA mutations are important causes. Several recurrent, pathogenic point mutations in the MTND3 gene - including m.10191T>C (p.Ser45Pro) - have been previously identified. In this short clinical review we evaluate the case reports of the m.10191T>C mutation causing complex I-deficient Leigh syndrome described in the literature, in addition to two new ones diagnosed in our laboratory. Both of these appear to have arisen de novo without transmission of the mutation from mother to offspring, illustrating the importance not only of fully characterizing the mitochondrial genome as part of the investigation of children with complex I-deficient Leigh syndrome but also of assessing maternal samples to provide crucial genetic advice for families.
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Affiliation(s)
- Victoria Nesbitt
- Mitochondrial Research Group, Institute for Ageing and Health, Newcastle University, Newcastle Upon Tyne, UK
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Mitochondrial dysfunction and genetic heterogeneity in chronic periodontitis. Mitochondrion 2011; 11:504-12. [DOI: 10.1016/j.mito.2011.01.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 11/20/2010] [Accepted: 01/25/2011] [Indexed: 11/18/2022]
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35
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Leshinsky-Silver E, Shuvalov R, Inbar S, Cohen S, Lev D, Lerman-Sagie T. Juvenile Leigh syndrome, optic atrophy, ataxia, dystonia, and epilepsy due to T14487C mutation in the mtDNA-ND6 gene: a mitochondrial syndrome presenting from birth to adolescence. J Child Neurol 2011; 26:476-81. [PMID: 21196529 DOI: 10.1177/0883073810384615] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An increasing number of reports describe mutations in mitochondrial DNA coding regions, especially in mitochondrial DNA- encoded nicotinamide adenine dinucleotide dehydrogenase subunit genes of the respiratory chain complex I, as causing early-onset Leigh syndrome. The authors report the molecular findings in a 24-year-old patient with juvenile-onset Leigh syndrome presenting with optic atrophy, ataxia dystonia, and epilepsy. A brain magnetic resonance imaging revealed bilateral basal ganglia and thalamic hypointensities, and a magnetic resonance spectroscopy revealed an increased lactate peak. The authors identified a T14487C change causing M63V substitution in the mitochondrial ND6 gene. The mutation was heteroplasmic in muscle and blood samples, with different mutation loads, and was absent in the patient's mother's urine and blood samples. They suggest that the T14487C mtDNA mutation should be analyzed in Leigh syndrome, presenting with optic atrophy, ataxia, dystonia, and epilepsy, regardless of age.
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Gerards M, van den Bosch BJC, Danhauser K, Serre V, van Weeghel M, Wanders RJA, Nicolaes GAF, Sluiter W, Schoonderwoerd K, Scholte HR, Prokisch H, Rötig A, de Coo IFM, Smeets HJM. Riboflavin-responsive oxidative phosphorylation complex I deficiency caused by defective ACAD9: new function for an old gene. Brain 2010; 134:210-9. [DOI: 10.1093/brain/awq273] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Steffen W, Gemperli AC, Cvetesic N, Steuber J. Organelle-specific expression of subunit ND5 of human complex I (NADH dehydrogenase) alters cation homeostasis in Saccharomyces cerevisiae. FEMS Yeast Res 2010; 10:648-59. [DOI: 10.1111/j.1567-1364.2010.00643.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Leshinsky-Silver E, Lev D, Malinger G, Shapira D, Cohen S, Lerman-Sagie T, Saada A. Leigh disease presenting in utero due to a novel missense mutation in the mitochondrial DNA-ND3. Mol Genet Metab 2010; 100:65-70. [PMID: 20202874 DOI: 10.1016/j.ymgme.2010.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Revised: 02/03/2010] [Accepted: 02/03/2010] [Indexed: 11/25/2022]
Abstract
Leigh syndrome can be caused by defects in both nuclear and mitochondrial genes involved in energy metabolism. Recently, an increasing number of mutations in mitochondrial DNA encoding regions, especially in NADH dehydrogenase (respiratory chain complex I) subunits, have been reported as causative of early onset Leigh syndrome. We describe a patient whose fetal brain ultrasound demonstrated periventricular pseudocyst suggestive of a possible mitochondrial disorder who presented postnatally with Leigh syndrome. A muscle biopsy demonstrated a partial decrease in complex I and pyruvate dehydrogenase (PDH-E1 alpha) activity. Sequencing of the PDH-E1 alpha gene did not reveal any mutation. Sequencing of the mtDNA revealed a novel heteroplasmic G10254A (D66N) mutation in the ND3 gene. This change results in a substitution of aspartic acid to asparagine in a highly conserved domain of the ND3 subunit. The mutation could not be detected in the mother's blood or urine sediment. Blue native gel electrophoresis of muscle mitochondria revealed a normal size, albeit a decreased level of complex I. The G10254A substitution in the mtDNA-ND3 gene is another cause of maternally inherited Leigh syndrome. This case demonstrates that periventricular pseudocysts may be the initial in utero presentation in patients with mitochondrial disorders. We emphasize the importance of screening the mtDNA in pediatric patients as the first step in molecular diagnosis of Leigh syndrome.
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Extensive screening system using suspension array technology to detect mitochondrial DNA point mutations. Mitochondrion 2010; 10:300-8. [PMID: 20064630 DOI: 10.1016/j.mito.2010.01.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 11/25/2009] [Accepted: 01/05/2010] [Indexed: 11/21/2022]
Abstract
We established an extensive and rapid system using suspension array to detect 61 representative mitochondrial DNA (mtDNA) heteroplasmic or homoplasmic point mutations (29 for Series A and 32 for Series B) in 22 genes: 1 each in MT-RNR1, -TV, -ND1, -TQ, -TW, -TC, and -TH genes; 2 each in MT-TN, -TG, -ND4, -TL2, -TE, and -CYB genes; 3 each in MT-ATP6, -ND3, and -ND5 genes; 4 each in MT-CO1 and -TK genes; 5 each in MT-TI, -TS1, and -ND6 genes; and 10 in the MT-TL1 gene. We carefully selected 5'-biotinylated primers and pooled primers for use in two sets of multiplex-PCR amplifications. To detect both mutant and wild-type mtDNA, even when polymorphisms were present near the target mutation sites, we designed specific oligonucleotide probes. By using the mtDNA point mutation detection system of Series A (29 mutations) and Series B (32 mutations), we screened a total of 3103 mutant sites in 107 DNA samples for Series A and 13,101 mutant sites in 397 DNA samples for Series B. We succeeded in determining 99.4% (Series A) and 99.6% (Series B) of the targeted mutant sites by use of the system. The 22 samples with the m.3243A>G heteroplasmic mutation revealed positive signals with both mutant- and wild-type-specific probes in this detection system with a detection limit of approximately 2%. This genetic screening platform is useful to reach a definitive diagnosis for mitochondrial diseases.
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Gerards M, Sluiter W, van den Bosch BJC, de Wit LEA, Calis CMH, Frentzen M, Akbari H, Schoonderwoerd K, Scholte HR, Jongbloed RJ, Hendrickx ATM, de Coo IFM, Smeets HJM. Defective complex I assembly due to C20orf7 mutations as a new cause of Leigh syndrome. J Med Genet 2009; 47:507-12. [PMID: 19542079 PMCID: PMC2921275 DOI: 10.1136/jmg.2009.067553] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Leigh syndrome is an early onset, progressive, neurodegenerative disorder with developmental and motor skills regression. Characteristic magnetic resonance imaging abnormalities consist of focal bilateral lesions in the basal ganglia and/or the brainstem. The main cause is a deficiency in oxidative phosphorylation due to mutations in an mtDNA or nuclear oxidative phosphorylation gene. METHODS AND RESULTS A consanguineous Moroccan family with Leigh syndrome comprise 11 children, three of which are affected. Marker analysis revealed a homozygous region of 11.5 Mb on chromosome 20, containing 111 genes. Eight possible mitochondrial candidate genes were sequenced. Patients were homozygous for an unclassified variant (p.P193L) in the cardiolipin synthase gene (CRLS1). As this variant was present in 20% of a Moroccan control population and enzyme activity was only reduced to 50%, this could not explain the rare clinical phenotype in our family. Patients were also homozygous for an amino acid substitution (p.L159F) in C20orf7, a new complex I assembly factor. Parents were heterozygous and unaffected sibs heterozygous or homozygous wild type. The mutation affects the predicted S-adenosylmethionine (SAM) dependent methyltransferase domain of C20orf7, possibly involved in methylation of NDUFB3 during the assembly process. Blue native gel electrophoresis showed an altered complex I assembly with only 30-40% of mature complex I present in patients and 70-90% in carriers. CONCLUSIONS A new cause of Leigh syndrome can be a defect in early complex I assembly due to C20orf7 mutations.
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Affiliation(s)
- M Gerards
- Department of Genetics and Cell Biology, Unit Clinical Genomics, Maastricht University, Maastricht, The Netherlands
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Mkaouar-Rebai E, Chaari W, Younes S, Bousoffara R, Sfar MT, Fakhfakh F. Maternally inherited Leigh syndrome: T8993G mutation in a Tunisian family. Pediatr Neurol 2009; 40:437-42. [PMID: 19433277 DOI: 10.1016/j.pediatrneurol.2009.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/31/2008] [Accepted: 01/06/2009] [Indexed: 10/20/2022]
Abstract
Leigh syndrome is a genetically heterogeneous, neurodegenerative disorder that predominantly affects children and leads to death within months or years. Mutations causing this disease have been found in both mitochondrial and nuclear DNA. The present report describes a Tunisian family with a maternally inherited Leigh syndrome harboring the mitochondrial T8993G mutation in the ATPase 6 gene. Polymerase chain reaction-restriction fragment length polymorphism analysis with the MspI restriction endonuclease, quantified with a digital image analyzer and gel documentation system, showed that the T8993G mutation was present with a high percentage in the blood of the three patients tested. This mutation was also detected in the asymptomatic mothers of these three patients (90, 96, and 60%). Two novel mitochondrial mutations were identified in the mitochondrial ATP6 gene -- T8741G (L72R) and A8795G (H90R) -- and three novel polymorphisms. Altogether, Leigh syndrome presenting the T8993G mutation in the ATPase 6 gene with variable heteroplasmic loads (44-98%) in a single Tunisian family is a novel finding.
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Affiliation(s)
- Emna Mkaouar-Rebai
- Laboratory of Molecular Human Genetics, Sfax Faculty of Medicine, Sfax, Tunisia.
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42
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Abstract
Leigh syndrome (also termed subacute, necrotizing encephalopathy) is a devastating neurodegenerative disorder, characterized by almost identical brain changes, e.g., focal, bilaterally symmetric lesions, particularly in the basal ganglia, thalamus, and brainstem, but with considerable clinical and genetic heterogeneity. Clinically, Leigh syndrome is characterized by a wide variety of abnormalities, from severe neurologic problems to a near absence of abnormalities. Most frequently the central nervous system is affected, with psychomotor retardation, seizures, nystagmus, ophthalmoparesis, optic atrophy, ataxia, dystonia, or respiratory failure. Some patients also present with peripheral nervous system involvement, including polyneuropathy or myopathy, or non-neurologic abnormalities, e.g., diabetes, short stature, hypertrichosis, cardiomyopathy, anemia, renal failure, vomiting, or diarrhea (Leigh-like syndrome). In the majority of cases, onset is in early childhood, but in a small number of cases, adults are affected. In the majority of cases, dysfunction of the respiratory chain (particularly complexes I, II, IV, or V), of coenzyme Q, or of the pyruvate dehydrogenase complex are responsible for the disease. Associated mutations affect genes of the mitochondrial or nuclear genome. Leigh syndrome and Leigh-like syndrome are the mitochondrial disorders with the largest genetic heterogeneity.
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Bamne MN, Talkowski ME, Moraes CT, Manuck SB, Ferrell RE, Chowdari KV, Nimgaonkar VL. Systematic association studies of mitochondrial DNA variations in schizophrenia: focus on the ND5 gene. Schizophr Bull 2008; 34:458-65. [PMID: 17898419 PMCID: PMC2632438 DOI: 10.1093/schbul/sbm100] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Postmortem studies, as well as genetic association studies, have implicated mitochondrial dysfunction in schizophrenia (SZ). We conducted multistaged analysis to assess the involvement of mitochondrial DNA (mtDNA) variations in SZ. Initially, the entire mtDNA genome was sequenced in pools of DNA from SZ cases and controls (n = 180 in each group, set 1). Two polymorphisms localized to the NADH dehydrogenase subunit 5 (ND5) gene demonstrated suggestive case control allele frequency differences (mtDNA 13368 G/A, p = .019 and mtDNA 13708G/A, p = .043). Hence, the ND5 gene was sequenced in individual samples from the initial panel of cases and controls. Additional subjects from another independent set of cases and controls (set 2, cases, n = 244, controls n = 508) were also sequenced individually. No significant differences in allele frequencies for mtDNA 13368 G/A, and mtDNA 13708G/A were observed. However, we identified 216 other rare variants, 53 of which were reported earlier in association studies of other mitochondrial disorders. We compared the distribution of polymorphisms in both sets of cases and controls. No significant case-control differences were observed in the smaller, first set. In the second set, cases had more variants overall (p = 0.014), as well as synonymous variants (p = 0.02), but the difference for nonsynonymous variants was not significant (p = 0.19). Screening available first-degree relatives (n = 10) revealed 10 maternally inherited variations, suggesting that not all the variants are somatic mutations. Further investigations are warranted.
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Affiliation(s)
- Mikhil N. Bamne
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213
| | - Michael E. Talkowski
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15213
| | - Carlos T. Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136
| | - Stephen B. Manuck
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Robert E. Ferrell
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15213
| | - Kodavali V. Chowdari
- Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213
| | - Vishwajit L. Nimgaonkar
- To whom correspondence should be addressed; Department of Psychiatry and Human Genetics, University of Pittsburgh School of Medicine and Graduate School of Public Health, Western Psychiatric Institute and Clinic, Room 443, Western Psychiatric Institute and Clinic, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213; tel: 412-246-6353, fax: 412-246-6350, e-mail:
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Sarzi E, Brown MD, Lebon S, Chretien D, Munnich A, Rotig A, Procaccio V. A novel recurrent mitochondrial DNA mutation in ND3 gene is associated with isolated complex I deficiency causing Leigh syndrome and dystonia. Am J Med Genet A 2007; 143A:33-41. [PMID: 17152068 DOI: 10.1002/ajmg.a.31565] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Defects in NADH:ubiquinone oxidoreductase (complex I), the largest complex of the mitochondrial respiratory chain, account for most cases of respiratory chain deficiency in human. Complex I contains at least 45 subunits, 7 of which are encoded by mitochondrial DNA (mtDNA). Here we report a novel 10197G>A mutation of the ND3 gene in three unrelated families with Leigh syndrome (LS) or dystonia. Variable degrees of heteroplasmy were found in all tissues tested and a high percentage of mutant mtDNA was observed in muscle. The 10197G>A mutation modifies a hydrophobic alanine residue into a hydrophilic threonine (A47T) in a highly conserved domain of ND3 subunit. Furthermore, this defect could be transferred along with the mutant mtDNAs to rho degrees lymphoblastoid cells in cybrid experiments. However, nuclear modifier genes may also play a role in the phenotypic expression and severity of the 10197G>A mutation. The association of the 10197G>A ND3 mutation with an isolated biochemical defect involving complex I and the discovery of the 10197G>A mutation with a similar phenotype in three unrelated families establish its pathogenicity and demonstrate that the amino acid position A47 is important for the function of complex I. These results show that the 10197G>A mutation in the mitochondrial ND3 gene should be considered as a common mtDNA mutation responsible for LS and dystonia.
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Affiliation(s)
- Emmanuelle Sarzi
- INSERM U781, Department of Genetics, Hôpital Necker-Enfants Malades, Paris, France
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Zhadanov SI, Grechanina EY, Grechanina YB, Gusar VA, Fedoseeva NP, Lebon S, Münnich A, Schurr TG. Fatal manifestation of a de novo ND5 mutation: Insights into the pathogenetic mechanisms of mtDNA ND5 gene defects. Mitochondrion 2007; 7:260-6. [PMID: 17317336 DOI: 10.1016/j.mito.2007.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 01/08/2007] [Accepted: 01/10/2007] [Indexed: 11/23/2022]
Abstract
We report the de novo occurrence of a heteroplasmic 12706T-->C (12705C) ND5 mutation associated with the clinical expression of fatal Leigh syndrome. Phylogenetic analysis of several cases having the 12706C mutation confirmed that this mutation occurred independently in distinctive mtDNA backgrounds. In each of these cases, the low level of heteroplasmy and the association of the mutation with a deleterious phenotype indicated that the 12706C had a primary role in the expression of LS/MELAS in its carriers. Secondary structure analysis of the ND5 protein further supported the deleterious role of the 12706C mutation, as it was found to affect a functionally significant transmembrane domain that is likely responsible for the proton-translocation function of complex I.
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Affiliation(s)
- Sergey I Zhadanov
- Department of Anthropology, University of Pennsylvania, 325 University Museum, 3260 South Street, Philadelphia, PA 19104-6398, USA.
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46
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Oldfors A, Tulinius M. Mitochondrial encephalomyopathies. HANDBOOK OF CLINICAL NEUROLOGY 2007; 86:125-165. [PMID: 18808998 DOI: 10.1016/s0072-9752(07)86006-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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47
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Janssen RJRJ, Nijtmans LG, van den Heuvel LP, Smeitink JAM. Mitochondrial complex I: structure, function and pathology. J Inherit Metab Dis 2006; 29:499-515. [PMID: 16838076 DOI: 10.1007/s10545-006-0362-4] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 05/31/2006] [Accepted: 06/01/2006] [Indexed: 10/24/2022]
Abstract
Oxidative phosphorylation (OXPHOS) has a prominent role in energy metabolism of the cell. Being under bigenomic control, correct biogenesis and functioning of the OXPHOS system is dependent on the finely tuned interaction between the nuclear and the mitochondrial genome. This suggests that disturbances of the system can be caused by numerous genetic defects and can result in a variety of metabolic and biochemical alterations. Consequently, OXPHOS deficiencies manifest as a broad clinical spectrum. Complex I, the biggest and most complicated enzyme complex of the OXPHOS system, has been subjected to thorough investigation in recent years. Significant progress has been made in the field of structure, composition, assembly, and pathology. Important gains in the understanding of the Goliath of the OXPHOS system are: exposing the electron transfer mechanism and solving the crystal structure of the peripheral arm, characterization of almost all subunits and some of their functions, and creating models to elucidate the assembly process with concomitant identification of assembly chaperones. Unravelling the intricate mechanisms underlying the functioning of this membrane-bound enzyme complex in health and disease will pave the way for developing adequate diagnostic procedures and advanced therapeutic treatment strategies.
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Affiliation(s)
- Rolf J R J Janssen
- Nijmegen Centre for Mitochondrial Disorders, Laboratory of Paediatrics and Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Valentino ML, Barboni P, Rengo C, Achilli A, Torroni A, Lodi R, Tonon C, Barbiroli B, Fortuna F, Montagna P, Baruzzi A, Carelli V. The 13042G --> A/ND5 mutation in mtDNA is pathogenic and can be associated also with a prevalent ocular phenotype. J Med Genet 2006; 43:e38. [PMID: 16816025 PMCID: PMC2564567 DOI: 10.1136/jmg.2005.037507] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 12/12/2005] [Accepted: 12/13/2005] [Indexed: 01/08/2023]
Abstract
BACKGROUND Overlapping phenotypes including LHON, MELAS, and Leigh syndrome have recently been associated with numerous mtDNA point mutations in the ND5 gene of complex I, now considered a mutational hot spot. OBJECTIVE To identify the mtDNA defect in a family with a prevalent ocular phenotype, including LHON-like optic neuropathy, retinopathy, and cataract, but characterised also by strokes, early deaths, and miscarriages on the maternal line. RESULTS Sequencing of the entire mitochondrial genome from the proband's muscle DNA identified the heteroplasmic 13042G-->A transition, which was previously described only once in a patient with a different mitochondrial disease. This mutation fulfils the major pathogenic criteria, inducing an amino acid change (A236T) at an invariant position in a highly conserved domain of the ND5 gene. Phosphorus magnetic resonance spectroscopy in the proband disclosed an in vivo brain and skeletal muscle energy metabolism deficit. CONCLUSIONS These findings conclusively establish the pathogenic role of the 13042G-->A mutation and underscore its variable clinical expression.
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Affiliation(s)
- M L Valentino
- Dipartimento di Scienze Neurologiche, Università di Bologna, Via Ugo Foscolo 7, 40123, Bologna, Italy
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49
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Blakely EL, Rennie KJ, Jones L, Elstner M, Chrzanowska-Lightowlers ZMA, White CB, Shield JPH, Pilz DT, Turnbull DM, Poulton J, Taylor RW. Sporadic intragenic inversion of the mitochondrial DNA MTND1 gene causing fatal infantile lactic acidosis. Pediatr Res 2006; 59:440-4. [PMID: 16492986 DOI: 10.1203/01.pdr.0000198771.78290.c4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mutations of mitochondrial DNA (mtDNA) are an important cause of genetic disease, yet rarely present in the neonatal period. Here we report the clinical, biochemical, and molecular genetic findings of an infant who died at the age of 1 mo with marked biventricular hypertrophy, aortic coarctation, and severe lactic acidosis due to a previously described but unusual mtDNA mutation, a 7-bp intragenic inversion within the mitochondrial gene encoding ND1 protein of complex I (MTND1). In direct contrast to the previous case, an adult with exercise intolerance who only harbored the mutation in muscle, the MTND1 inversion in our patient was present at high levels in several tissues including the heart, muscle, liver, and cultured skin fibroblasts. There was no evidence of the mutation or respiratory complex I defect in a muscle biopsy from the patient's mother. Transmitochondrial cytoplasmic hybrids (cybrids) containing high mutant loads of the inversion expressed the biochemical defect but apparently normal levels of the assembled complex. Our report highlights the enormous phenotypic diversity that exists among pathogenic mtDNA mutations and reemphasizes the need for appropriate genetic counseling for families affected by mtDNA disease.
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Affiliation(s)
- Emma L Blakely
- Mitochindrial Research Group, School of Neurlogy, Neurobiology and Psychiatry, The University of Newcastle upon Tyne, UK
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Leshinsky-Silver E, Lev D, Tzofi-Berman Z, Cohen S, Saada A, Yanoov-Sharav M, Gilad E, Lerman-Sagie T. Fulminant neurological deterioration in a neonate with Leigh syndrome due to a maternally transmitted missense mutation in the mitochondrial ND3 gene. Biochem Biophys Res Commun 2005; 334:582-7. [PMID: 16023078 DOI: 10.1016/j.bbrc.2005.06.134] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 06/20/2005] [Indexed: 10/25/2022]
Abstract
Leigh syndrome can result from both nuclear and mitochondrial DNA defects. Mutations in complex V genes of the respiratory chain were considered until recently as the most frequent cause for mitochondrial inherited Leigh syndrome, while gene defects in complex I were related to recessive Leigh syndrome. Recently few reports of mutations in the mitochondrial-encoded complex I subunit genes causing Leigh syndrome have been reported. We describe a 1-month-old baby who acutely deteriorated, with abrupt onset of brainstem dysfunction, due to basal ganglia lesions extending to the brainstem. A muscle biopsy demonstrated complex I deficiency. Subsequent analysis of the mitochondrial genome revealed a homoplastic T10191C mutation in the ND3 gene (in blood and muscle), resulting in a substitution of serine to proline. Hair root analysis revealed a 50% mutant load, reflecting heteroplasmy in early embryonic stages. The mutation was also detected in his mother (5%). Western blot analysis revealed a decrease of the 20 kDa subunit (likely ND6) and of the 30 kDa subunit (NDUFA9), which is probably due to instability attributed to the inability to form subcomplexes with ND3. This is the first description of infantile Leigh syndrome due to a maternally transmitted T10191C substitution in ND3 and not due to a de novo mutation. This mutation is age and tissue dependent and therefore may not be amenable to prenatal testing.
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