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Strasser L, Doja A, Davila J, Chakraborty P, Bourque DK. The mitochondrial tRNA MT-TW m.5537_5538insT variant presents with significant intra-familial clinical variability. Am J Med Genet A 2023; 191:2890-2897. [PMID: 37654102 DOI: 10.1002/ajmg.a.63378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 06/12/2023] [Accepted: 07/29/2023] [Indexed: 09/02/2023]
Abstract
Mitochondrial disorders can present with a wide range of clinical and biochemical phenotypes. Mitochondrial DNA variants may be influenced by factors such as degree of heteroplasmy and tissue distribution. We present a four-generation family in which 10 individuals carry a pathogenic mitochondrial variant (m.5537_5538insT, MT-TW gene) with differing levels of heteroplasmy and clinical features. This genetic variant has been documented in two prior reports, both in individuals with Leigh syndrome. In the current family, three individuals have severe mitochondrial symptoms including Leigh syndrome (patient 1, 100% in blood), MELAS (patient 2, 97% heteroplasmy in muscle), and MELAS-like syndrome (patient 3, 50% heteroplasmy in blood and 100% in urine). Two individuals have mild mitochondrial symptoms (patient 4, 50% in blood and 67% in urine and patient 5, 50% heteroplasmy in blood and 30% in urine). We observe that this variant is associated with multiple mitochondrial presentations and phenotypes, including MELAS syndrome for which this variant has not previously been reported. We also demonstrate that the level of heteroplasmy of the mitochondrial DNA variant correlates with the severity of clinical presentation; however, not with the specific mitochondrial syndrome.
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Affiliation(s)
- Lauren Strasser
- Division of Pediatric Neurology, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Asif Doja
- Division of Pediatric Neurology, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
- Department of Pediatrics, University of Ottawa, Ottawa, Ontario, Canada
| | - Jorge Davila
- Department of Medical Imaging, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
- Department of Radiology, University of Ottawa, Ottawa, Ontario, Canada
| | - Pranesh Chakraborty
- Department of Pediatrics, University of Ottawa, Ottawa, Ontario, Canada
- Division of Metabolics and Newborn Screening, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Danielle K Bourque
- Department of Pediatrics, University of Ottawa, Ottawa, Ontario, Canada
- Division of Metabolics and Newborn Screening, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
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2
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Zhang TG, Miao CY. Mitochondrial transplantation as a promising therapy for mitochondrial diseases. Acta Pharm Sin B 2022; 13:1028-1035. [PMID: 36970208 PMCID: PMC10031255 DOI: 10.1016/j.apsb.2022.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/25/2022] [Accepted: 08/18/2022] [Indexed: 11/28/2022] Open
Abstract
Mitochondrial diseases are a group of inherited or acquired metabolic disorders caused by mitochondrial dysfunction which may affect almost all the organs in the body and present at any age. However, no satisfactory therapeutic strategies have been available for mitochondrial diseases so far. Mitochondrial transplantation is a burgeoning approach for treatment of mitochondrial diseases by recovery of dysfunctional mitochondria in defective cells using isolated functional mitochondria. Many models of mitochondrial transplantation in cells, animals, and patients have proved effective via various routes of mitochondrial delivery. This review presents different techniques used in mitochondrial isolation and delivery, mechanisms of mitochondrial internalization and consequences of mitochondrial transplantation, along with challenges for clinical application. Despite some unknowns and challenges, mitochondrial transplantation would provide an innovative approach for mitochondrial medicine.
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Affiliation(s)
| | - Chao-yu Miao
- Corresponding author. Tel: +86 21 81871271; fax: +86 21 65493951.
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3
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Fan HC, Lee HF, Yue CT, Chi CS. Clinical Characteristics of Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes. Life (Basel) 2021; 11:life11111111. [PMID: 34832987 PMCID: PMC8617702 DOI: 10.3390/life11111111] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/11/2021] [Accepted: 10/16/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, a maternally inherited mitochondrial disorder, is characterized by its genetic, biochemical and clinical complexity. The most common mutation associated with MELAS syndrome is the mtDNA A3243G mutation in the MT-TL1 gene encoding the mitochondrial tRNA-leu(UUR), which results in impaired mitochondrial translation and protein synthesis involving the mitochondrial electron transport chain complex subunits, leading to impaired mitochondrial energy production. Angiopathy, either alone or in combination with nitric oxide (NO) deficiency, further contributes to multi-organ involvement in MELAS syndrome. Management for MELAS syndrome is amostly symptomatic multidisciplinary approach. In this article, we review the clinical presentations, pathogenic mechanisms and options for management of MELAS syndrome.
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Affiliation(s)
- Hueng-Chuen Fan
- Department of Pediatrics, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan; (H.-C.F.); (C.-T.Y.)
- Department of Medical Research, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan
- Department of Rehabilitation, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli 356, Taiwan
- Department of Life Sciences, Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
| | - Hsiu-Fen Lee
- Department of Pediatrics, Taichung Veterans General Hospital, Taichung 407, Taiwan;
| | - Chen-Tang Yue
- Department of Pediatrics, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan; (H.-C.F.); (C.-T.Y.)
| | - Ching-Shiang Chi
- Department of Pediatrics, Tungs’ Taichung Metroharbor Hospital, Wuchi, Taichung 435, Taiwan; (H.-C.F.); (C.-T.Y.)
- Correspondence: ; Tel.: +886-4-26581919-4301
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4
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The Diagnostic Approach to Mitochondrial Disorders in Children in the Era of Next-Generation Sequencing: A 4-Year Cohort Study. J Clin Med 2021; 10:jcm10153222. [PMID: 34362006 PMCID: PMC8348083 DOI: 10.3390/jcm10153222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/08/2021] [Accepted: 07/20/2021] [Indexed: 11/25/2022] Open
Abstract
Mitochondrial diseases (MDs) are a large group of genetically determined multisystem disorders, characterized by extreme phenotypic heterogeneity, attributable in part to the dual genomic control (nuclear and mitochondrial DNA) of the mitochondrial proteome. Advances in next-generation sequencing technologies over the past two decades have presented clinicians with a challenge: to select the candidate disease-causing variants among the huge number of data provided. Unfortunately, the clinical tools available to support genetic interpretations still lack specificity and sensitivity. For this reason, the diagnosis of MDs continues to be difficult, with the new “genotype first” approach still failing to diagnose a large group of patients. With the aim of investigating possible relationships between clinical and/or biochemical phenotypes and definitive molecular diagnoses, we performed a retrospective multicenter study of 111 pediatric patients with clinical suspicion of MD. In this cohort, the strongest predictor of a molecular (in particular an mtDNA-related) diagnosis of MD was neuroimaging evidence of basal ganglia (BG) involvement. Regression analysis confirmed that normal BG imaging predicted negative genetic studies for MD. Psychomotor regression was confirmed as an independent predictor of a definitive diagnosis of MD. The findings of this study corroborate previous data supporting a role for neuroimaging in the diagnostic approach to MDs and reinforce the idea that mtDNA sequencing should be considered for first-line testing, at least in specific groups of children.
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5
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Bassett JT, Rodriguez B, Mulligan L, Fontana RJ. Acute liver failure in a military recruit treated with valproic acid and harboring a previously unrecognized POLG-1 mutation. Epilepsy Behav Rep 2019; 12:100342. [PMID: 31799506 PMCID: PMC6883298 DOI: 10.1016/j.ebr.2019.100342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 10/13/2019] [Accepted: 10/18/2019] [Indexed: 02/07/2023] Open
Abstract
Patients with mutations in the POLG-1 gene often are afflicted with drug-resistant seizures at an early age and have an increased risk of valproic acid-induced acute liver failure. Severe valproate hepatotoxicity most commonly arises in children within the first 3 months of treatment with an overall estimated incidence of 1 in 40,000 treated patients. Due to high mortality rates among transplanted children, many experts consider valproic acid-induced acute liver failure in patients with mitochondrial disorders to be a contraindication to liver transplant. We report the successful use of liver transplantation in a young man with valproic acid-associated acute liver failure harboring a previously unrecognized POLG-1 mutation. Patients with mutations in the POLG-1 gene often have an increased risk of valproic acid (VPA) induced acute liver failure. Severe valproate hepatotoxicity most commonly arises in children within the first 3 months of treatment. Many experts consider VPA induced acute liver failure with mitochondrial disorders a contraindication to liver transplant. We report a case of acute liver failure associated with VPA treated successfully with a liver transplant
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Affiliation(s)
| | | | - Lisa Mulligan
- Naval Medical Center Portsmouth, Portsmouth, VA, United States of America
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6
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Ruiz M, Cuillerier A, Daneault C, Deschênes S, Frayne IR, Bouchard B, Forest A, Legault JT, Vaz FM, Rioux JD, Burelle Y, Des Rosiers C. Lipidomics unveils lipid dyshomeostasis and low circulating plasmalogens as biomarkers in a monogenic mitochondrial disorder. JCI Insight 2019; 4:123231. [PMID: 31341105 DOI: 10.1172/jci.insight.123231] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 05/31/2019] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial dysfunction characterizes many rare and common age-associated diseases. The biochemical consequences, underlying clinical manifestations, and potential therapeutic targets, remain to be better understood. We tested the hypothesis that lipid dyshomeostasis in mitochondrial disorders goes beyond mitochondrial fatty acid β-oxidation, particularly in liver. This was achieved using comprehensive untargeted and targeted lipidomics in a case-control cohort of patients with Leigh syndrome French-Canadian variant (LSFC), a mitochondrial disease caused by mutations in LRPPRC, and in mice harboring liver-specific inactivation of Lrpprc (H-Lrpprc-/-). We discovered a plasma lipid signature discriminating LSFC patients from controls encompassing lower levels of plasmalogens and conjugated bile acids, which suggest perturbations in peroxisomal lipid metabolism. This premise was reinforced in H-Lrpprc-/- mice, which compared with littermates recapitulated a similar, albeit stronger peroxisomal metabolic signature in plasma and liver including elevated levels of very-long-chain acylcarnitines. These mice also presented higher transcript levels for hepatic markers of peroxisome proliferation in addition to lipid remodeling reminiscent of nonalcoholic fatty liver diseases. Our study underscores the value of lipidomics to unveil unexpected mechanisms underlying lipid dyshomeostasis ensuing from mitochondrial dysfunction herein implying peroxisomes and liver, which likely contribute to the pathophysiology of LSFC, but also other rare and common mitochondrial diseases.
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Affiliation(s)
- Matthieu Ruiz
- Department of Nutrition and.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada.,Montreal Heart Institute Research Center, Montreal, Quebec, Canada
| | - Alexanne Cuillerier
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences and Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Sonia Deschênes
- Montreal Heart Institute Research Center, Montreal, Quebec, Canada
| | | | | | - Anik Forest
- Montreal Heart Institute Research Center, Montreal, Quebec, Canada
| | | | | | - Frederic M Vaz
- Amsterdam UMC, University of Amsterdam, Laboratory Genetic Metabolic Diseases, Core Facility Metabolomics, Amsterdam Gastroenterology & Metabolism, Meibergdreef, Amsterdam, Netherlands
| | - John D Rioux
- Department of Medicine, Université de Montréal, Montreal, Quebec, Canada.,Montreal Heart Institute Research Center, Montreal, Quebec, Canada
| | - Yan Burelle
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences and Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Christine Des Rosiers
- Department of Nutrition and.,Montreal Heart Institute Research Center, Montreal, Quebec, Canada
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7
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Florea A, Varga AP, Matei HV. Ultrastructural variability of mitochondrial cristae induced in vitro by bee (Apis mellifera) venom and its derivatives, melittin and phospholipase A2, in isolated rat adrenocortical mitochondria. Micron 2018; 112:42-54. [PMID: 29908421 DOI: 10.1016/j.micron.2018.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/08/2018] [Accepted: 06/08/2018] [Indexed: 12/20/2022]
Abstract
We tested the ability of bee venom (BV), melittin (Mlt), and phospholipase A2 (PLA) - used in 5 concentrations each (5, 10, 15, 20 and 40 μg/100 μl) - to promote ultrastructural changes and reorganization of cristae in vitro in mitochondria isolated from rat adrenal cortex after a protocol optimized by us. Thus, apart from two control grups (CI and CS), in which the mitochondria were suspended into saline buffer and isolation medium respectively, 15 more groups of mitochondria were constituted, corresponding to the five different doses of the three substance tested (BV5 to M40; M5 to M40 and P5 to P40). The ultrastructural effects were quantified on transmission electron micrographs using a morphometry software. Values of 84.49 nm and 95.45 nm were calculated for median diameters of mitochondrial cristae in two control groups. Large and very large vesicular cristae, many with 2 or 3 membranes, were generated depending on dose among normal cristae in all treated groups. In the BV and Mlt treated groups, after an initial increase (up to 127.27 nm in V15 group and 151.2 nm in M10 group) due to stimulation of cristae fusion, the cristae diameter diminished as the doses increased, mainly by the collapse of the cristae. In the PLA treated groups, the cristae diameter increased continuously from 83.84 nm to 136.01 nm, by stimulated fusion of cristae, only the two largest doses promoting the collapse of cristae in some mitochondria. The highest percentage of abnormal cristae was found in the Mlt treated groups and next in BV treated groups. All substances tested produced pronounced ultrastructural variability of mitochondrial cristae in vitro: they also changed (depending on dose) mitochondrial shapes, generated matrix debris and the highest concentrations of BV and Mlt were responsible for mitochondrial breakdown. These ultrastructural alterations of mitochondrial criste in the presence of the BV molecules suggest a reduced capacity of adrenocortical mitochondria to synthetize steroid hormones consequently to BV envenomations and partially explain the toxic effects of the BV.
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Affiliation(s)
- Adrian Florea
- Department of Cell and Molecular Biology, Faculty of Medicine, "Iuliu Haţieganu" University of Medicine and Pharmacy, 6 L. Pasteur St., 400349 Cluj-Napoca, Romania.
| | - Andrei Patrick Varga
- Department of Cell and Molecular Biology, Faculty of Medicine, "Iuliu Haţieganu" University of Medicine and Pharmacy, 6 L. Pasteur St., 400349 Cluj-Napoca, Romania; Jibou County Hospital, 28 Libertatii St., 455200 Jibou, Romania.
| | - Horea Vladi Matei
- Department of Cell and Molecular Biology, Faculty of Medicine, "Iuliu Haţieganu" University of Medicine and Pharmacy, 6 L. Pasteur St., 400349 Cluj-Napoca, Romania.
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8
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Poulton J, Finsterer J, Yu-Wai-Man P. Genetic Counselling for Maternally Inherited Mitochondrial Disorders. Mol Diagn Ther 2018; 21:419-429. [PMID: 28536827 DOI: 10.1007/s40291-017-0279-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aim of this review was to provide an evidence-based approach to frequently asked questions relating to the risk of transmitting a maternally inherited mitochondrial disorder (MID). We do not address disorders linked with disturbed mitochondrial DNA (mtDNA) maintenance, causing mtDNA depletion or multiple mtDNA deletions, as these are autosomally inherited. The review addresses questions regarding prognosis, recurrence risks and the strategies available to prevent disease transmission. The clinical and genetic complexity of maternally inherited MIDs represent a major challenge for patients, their relatives and health professionals. Since many of the genetic and pathophysiological aspects of MIDs remain unknown, counselling of affected patients and at-risk family members remains difficult. MtDNA mutations are maternally transmitted or, more rarely, they are sporadic, occurring de novo (~25%). Females carrying homoplasmic mtDNA mutations will transmit the mutant species to all of their offspring, who may or may not exhibit a similar phenotype depending on modifying, secondary factors. Females carrying heteroplasmic mtDNA mutations will transmit a variable amount of mutant mtDNA to their offspring, which can result in considerable phenotypic heterogeneity among siblings. The majority of mtDNA rearrangements, such as single large-scale deletions, are sporadic, but there is a small risk of recurrence (~4%) among the offspring of affected women. The range and suitability of reproductive choices for prospective mothers is a complex area of mitochondrial medicine that needs to be managed by experienced healthcare professionals as part of a multidisciplinary team. Genetic counselling is facilitated by the identification of the underlying causative genetic defect. To provide more precise genetic counselling, further research is needed to clarify the secondary factors that account for the variable penetrance and the often marked differential expressivity of pathogenic mtDNA mutations both within and between families.
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Affiliation(s)
- Joanna Poulton
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford, UK
| | - Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach 20, 1180, Vienna, Austria.
| | - Patrick Yu-Wai-Man
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK.,NIHR Biomedical Research Centre, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK.,Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
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9
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Finsterer J, Zarrouk-Mahjoub S. Regional cerebral hyperperfusion: A biomarker of upcoming stroke-like episodes? J Magn Reson Imaging 2018; 47:582. [DOI: 10.1002/jmri.25735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 03/30/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
| | - Sinda Zarrouk-Mahjoub
- University of Tunis El Manar and Genomics Platform, Pasteur Institute of Tunis; Tunisia
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10
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Cuillerier A, Honarmand S, Cadete VJJ, Ruiz M, Forest A, Deschênes S, Beauchamp C, Charron G, Rioux JD, Des Rosiers C, Shoubridge EA, Burelle Y. Loss of hepatic LRPPRC alters mitochondrial bioenergetics, regulation of permeability transition and trans-membrane ROS diffusion. Hum Mol Genet 2018; 26:3186-3201. [PMID: 28575497 DOI: 10.1093/hmg/ddx202] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/19/2017] [Indexed: 12/19/2022] Open
Abstract
The French-Canadian variant of Leigh Syndrome (LSFC) is an autosomal recessive oxidative phosphorylation (OXPHOS) disorder caused by a mutation in LRPPRC, coding for a protein involved in the stability of mitochondrially-encoded mRNAs. Low levels of LRPPRC are present in all patient tissues, but result in a disproportionately severe OXPHOS defect in the brain and liver, leading to unpredictable subacute metabolic crises. To investigate the impact of the OXPHOS defect in the liver, we analyzed the mitochondrial phenotype in mice harboring an hepatocyte-specific inactivation of Lrpprc. Loss of LRPPRC in the liver caused a generalized growth delay, and typical histological features of mitochondrial hepatopathy. At the molecular level, LRPPRC deficiency caused destabilization of polyadenylated mitochondrial mRNAs, altered mitochondrial ultrastructure, and a severe complex IV (CIV) and ATP synthase (CV) assembly defect. The impact of LRPPRC deficiency was not limited to OXPHOS, but also included impairment of long-chain fatty acid oxidation, a striking dysregulation of the mitochondrial permeability transition pore, and an unsuspected alteration of trans-membrane H2O2 diffusion, which was traced to the ATP synthase assembly defect, and to changes in the lipid composition of mitochondrial membranes. This study underscores the value of mitochondria phenotyping to uncover complex and unexpected mechanisms contributing to the pathophysiology of mitochondrial disorders.
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Affiliation(s)
| | - Shamisa Honarmand
- Department of Human Genetics, Montreal Neurological Institute McGill University, Montreal, QC H3A 2B4, Canada
| | | | - Matthieu Ruiz
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
| | - Anik Forest
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
| | - Sonia Deschênes
- Faculty of Pharmacy, University of Montreal, Montreal, QC H3C 3J7, Canada.,Faculty of Medicine and Department of Nutrition, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | | | | | - Guy Charron
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
| | - John D Rioux
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada
| | - Christine Des Rosiers
- Research Center, Montreal Heart Institute, Montreal, QC H1T 1C8, Canada.,Faculty of Medicine and Department of Nutrition, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | - Eric A Shoubridge
- Department of Human Genetics, Montreal Neurological Institute McGill University, Montreal, QC H3A 2B4, Canada
| | - Yan Burelle
- Faculty of Pharmacy, University of Montreal, Montreal, QC H3C 3J7, Canada
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11
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Mitochondrial Diseases as Model of Neurodegeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1007:129-155. [DOI: 10.1007/978-3-319-60733-7_8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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12
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Zanolini A, Potic A, Carrara F, Lamantea E, Diodato D, Blasevich F, Marchet S, Mora M, Pallotti F, Morandi L, Zeviani M, Lamperti C. Pure myopathy with enlarged mitochondria associated to a new mutation in MTND2 gene. Mol Genet Metab Rep 2016; 10:24-27. [PMID: 28070494 PMCID: PMC5217772 DOI: 10.1016/j.ymgmr.2016.11.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/30/2016] [Accepted: 11/30/2016] [Indexed: 11/30/2022] Open
Abstract
To date, only few mutations in the mitochondrial DNA (mtDNA)-encoded ND2 subunit of Complex I have been reported, usually presenting a severe phenotype characterized by early onset encephalomyopathy and early death. In this report, we describe a new mutation in the MTND2 gene in a 21-year-old man with a mild myopathic phenotype characterized by exercise intolerance and increased plasma lactate at rest. Electromyography and brain NMR were normal, and no cardiac involvement was present. Muscle biopsy showed a massive presence of ragged red – COX-positive fibres, with enlarged mitochondria containing osmiophilic inclusions. Biochemical assays revealed a severe isolated complex I deficiency. We identified a novel, heteroplasmic mutation m.4831G > A in the MTND2 gene, causing the p.Gly121Asp substitution in the ND2 protein. The mutation was present in the 95% of mitochondrial genomes from patient's muscle tissue, at a lower level in cells from the urinary tract and at a lowest level in lymphocytes from patient's blood; the base substitution was absent in fibroblasts and in the tissues from proband's healthy mother and brother. The specific skeletal muscle tissue involvement can explain the childhood-onset and the relatively benign, exclusively myopathic course of the disease.
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Affiliation(s)
- Alice Zanolini
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy
| | - Ana Potic
- Clinic for Child Neurology and Psychiatry, Department of Neurology, Medical Faculty University of Belgrade, Belgrade 11000, Serbia
| | - Franco Carrara
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy
| | - Eleonora Lamantea
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy
| | - Daria Diodato
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy; Division of Neuromuscular and Neurodegenerative Disorders, Ospedale Pediatrico Bambin Gesu, Rome, Italy
| | - Flavia Blasevich
- IV Division of Neurology, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy
| | - Silvia Marchet
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy
| | - Marina Mora
- IV Division of Neurology, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy
| | - Francesco Pallotti
- Dept of Surgical and Morphological Sciences, University of Insubria, Varese, Italy
| | - Lucia Morandi
- IV Division of Neurology, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy
| | - Massimo Zeviani
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy; Mitochondrial Biology Unit, Medical Research Council, Cambridge CB2 0XY, UK
| | - Costanza Lamperti
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', 20126 Milan, Italy
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13
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Stiles AR, Simon MT, Stover A, Eftekharian S, Khanlou N, Wang HL, Magaki S, Lee H, Partynski K, Dorrani N, Chang R, Martinez-Agosto JA, Abdenur JE. Mutations in TFAM, encoding mitochondrial transcription factor A, cause neonatal liver failure associated with mtDNA depletion. Mol Genet Metab 2016; 119:91-9. [PMID: 27448789 DOI: 10.1016/j.ymgme.2016.07.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/01/2016] [Accepted: 07/02/2016] [Indexed: 10/21/2022]
Abstract
In humans, mitochondrial DNA (mtDNA) depletion syndromes are a group of genetically and clinically heterogeneous autosomal recessive disorders that arise as a consequence of defects in mtDNA replication or nucleotide synthesis. Clinical manifestations are variable and include myopathic, encephalomyopathic, neurogastrointestinal or hepatocerebral phenotypes. Through clinical exome sequencing, we identified a homozygous missense variant (c.533C>T; p.Pro178Leu) in mitochondrial transcription factor A (TFAM) segregating in a consanguineous kindred of Colombian-Basque descent in which two siblings presented with IUGR, elevated transaminases, conjugated hyperbilirubinemia and hypoglycemia with progression to liver failure and death in early infancy. Results of the liver biopsy in the proband revealed cirrhosis, micro- and macrovesicular steatosis, cholestasis and mitochondrial pleomorphism. Electron microscopy of muscle revealed abnormal mitochondrial morphology and distribution while enzyme histochemistry was underwhelming. Electron transport chain testing in muscle showed increased citrate synthase activity suggesting mitochondrial proliferation, while respiratory chain activities were at the lower end of normal. mtDNA content was reduced in liver and muscle (11% and 21% of normal controls respectively). While Tfam mRNA expression was upregulated in primary fibroblasts, Tfam protein level was significantly reduced. Furthermore, functional investigations of the mitochondria revealed reduced basal respiration and spare respiratory capacity, decreased mtDNA copy number and markedly reduced nucleoids. TFAM is essential for transcription, replication and packaging of mtDNA into nucleoids. Tfam knockout mice display embryonic lethality secondary to severe mtDNA depletion. In this report, for the first time, we associate a homozygous variant in TFAM with a novel mtDNA depletion syndrome.
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Affiliation(s)
- Ashlee R Stiles
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA; UCLA Clinical Genomics Center, Los Angeles, CA 90095, USA
| | - Mariella T Simon
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA; Department of Developmental and Cellular Biology, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Alexander Stover
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
| | - Shaya Eftekharian
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
| | - Negar Khanlou
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Hanlin L Wang
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Shino Magaki
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Hane Lee
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA; UCLA Clinical Genomics Center, Los Angeles, CA 90095, USA
| | - Kate Partynski
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
| | - Nagmeh Dorrani
- Department of Pediatrics, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Richard Chang
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA
| | - Julian A Martinez-Agosto
- UCLA Clinical Genomics Center, Los Angeles, CA 90095, USA; Department of Pediatrics, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA; Department of Human Genetics, David Geffen School of Medicine at University of California Los Angeles, CA 90095, USA
| | - Jose E Abdenur
- Division of Metabolic Disorders, CHOC Children's, Orange, CA 92868, USA; Department of Pediatrics, University of California Irvine, Orange, CA 92868, USA.
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14
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Lipoyltransferase 1 Gene Defect Resulting in Fatal Lactic Acidosis in Two Siblings. Case Rep Obstet Gynecol 2016; 2016:6520148. [PMID: 27247813 PMCID: PMC4877452 DOI: 10.1155/2016/6520148] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/30/2016] [Accepted: 04/17/2016] [Indexed: 12/02/2022] Open
Abstract
A term male neonate developed severe intractable lactic acidosis on day of life 1 and died the same day at our institution. The family previously lost another term, female newborn on day of life 1 from suspected sepsis at an outside hospital. After performing an autopsy on the neonate who died at our institution, extensive and lengthy neonatal and parental genetic testing, as well as biochemical analyses, and whole exome sequencing analysis identified compound heterozygous mutations in the lipoyltransferase 1 (LIPT1) gene responsible for the lipoylation of the 2-keto dehydrogenase complexes in the proband. These mutations were also identified in the deceased sibling. The clinical manifestations of these two siblings are consistent with those recently described in two unrelated families with lactic acidosis due to LIPT1 mutations, an underrecognized and underreported cause of neonatal death. Conclusions. Our observations contribute to the delineation of a new autosomal recessive metabolic disorder, leading to neonatal death. Our case report also highlights the importance of an interdisciplinary team in solving challenging cases.
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15
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Raghuvanshi R, Chaudhari A, Kumar GN. Amelioration of cadmium- and mercury-induced liver and kidney damage in rats by genetically engineered probiotic Escherichia coli Nissle 1917 producing pyrroloquinoline quinone with oral supplementation of citric acid. Nutrition 2016; 32:1285-94. [PMID: 27209211 DOI: 10.1016/j.nut.2016.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 02/26/2016] [Accepted: 03/10/2016] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Antioxidants, chelating agents, and probiotics are used to manage the toxic effects of cadmium (Cd) and mercury (Hg). The aim of this study was to investigate the combined effects of antioxidants, chelating agents, and probiotics against heavy metal toxicity. METHOD Genetically modified probiotic Escherichia coli Nissle 1917 (EcN-20) producing a potent water soluble antioxidant pyrroloquinoline quinone (PQQ) was supplemented with oral citric acid and compared with another genetically modified probiotic EcN-21 producing PQQ and citric acid against oxidative stress induced by Cd and Hg. Rats were independently given 100 ppm Cd and 80 ppm Hg in drinking water for 4 wk. RESULTS EcN-20 was found to be more effective than EcN-2 (EcN strain with genomic integration of vgb and gfp genes) with orally given PQQ against oxidative stress induced by Cd and Hg. EcN-20 supplemented with oral citric acid was more effective against Cd and Hg toxicity compared with EcN-2+citric acid (oral), EcN-2+PQQ (oral), EcN-2+PQQ (oral)+citric acid (oral), EcN-20, and EcN-21. However, protection shown by EcN-21 was similar to EcN-20. CONCLUSION The combination therapy involving probiotic EcN-20 producing PQQ with citric acid given orally was found to be a moderately effective strategy against toxicity induced by Cd and Hg, whereas the protective effect of EcN-21 was the same as EcN-20.
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Affiliation(s)
- Ruma Raghuvanshi
- Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Gujarat, India
| | - Archana Chaudhari
- Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Gujarat, India
| | - G Naresh Kumar
- Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Gujarat, India.
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16
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A Metabolic Signature of Mitochondrial Dysfunction Revealed through a Monogenic Form of Leigh Syndrome. Cell Rep 2015; 13:981-9. [PMID: 26565911 PMCID: PMC4644511 DOI: 10.1016/j.celrep.2015.09.054] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 07/13/2015] [Accepted: 09/18/2015] [Indexed: 11/20/2022] Open
Abstract
A decline in mitochondrial respiration represents the root cause of a large number of inborn errors of metabolism. It is also associated with common age-associated diseases and the aging process. To gain insight into the systemic, biochemical consequences of respiratory chain dysfunction, we performed a case-control, prospective metabolic profiling study in a genetically homogenous cohort of patients with Leigh syndrome French Canadian variant, a mitochondrial respiratory chain disease due to loss-of-function mutations in LRPPRC. We discovered 45 plasma and urinary analytes discriminating patients from controls, including classic markers of mitochondrial metabolic dysfunction (lactate and acylcarnitines), as well as unexpected markers of cardiometabolic risk (insulin and adiponectin), amino acid catabolism linked to NADH status (α-hydroxybutyrate), and NAD+ biosynthesis (kynurenine and 3-hydroxyanthranilic acid). Our study identifies systemic, metabolic pathway derangements that can lie downstream of primary mitochondrial lesions, with implications for understanding how the organelle contributes to rare and common diseases.
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17
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Chung WK, Martin K, Jalas C, Braddock SR, Juusola J, Monaghan KG, Warner B, Franks S, Yudkoff M, Lulis L, Rhodes RH, Prasad V, Torti E, Cho MT, Shinawi M. Mutations inCOQ4, an essential component of coenzyme Q biosynthesis, cause lethal neonatal mitochondrial encephalomyopathy. J Med Genet 2015; 52:627-35. [DOI: 10.1136/jmedgenet-2015-103140] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/17/2015] [Indexed: 12/16/2022]
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18
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Turkmenoglu FP, Kasirga UB, Celik HH. Ultra-structural hair alterations in Friedreich's ataxia: A scanning electron microscopic investigation. Microsc Res Tech 2015; 78:731-6. [PMID: 26138268 DOI: 10.1002/jemt.22531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/05/2015] [Accepted: 05/22/2015] [Indexed: 11/07/2022]
Abstract
Friedreich's ataxia (FRDA) is an autosomal recessive inherited disorder involving progressive damage to the central and peripheral nervous systems and cardiomyopathy. FRDA is caused by the silencing of the FXN gene and reduced levels of the encoded protein, frataxin. Frataxin is a mitochondrial protein that functions primarily in iron-sulfur cluster synthesis. Skin disorders including hair abnormalities have previously been reported in patients with mitochondrial disorders. However, to our knowledge, ultra-structural hair alterations in FRDA were not demonstrated. The purpose of this study was to determine ultra-structural alterations in the hairs of FRDA patients as well as carriers. Hair specimen from four patients, who are in different stages of the disease, and two carriers were examined by scanning electron microscope. Thin and weak hair follicles with absence of homogeneities on the cuticular surface, local damages of the cuticular layer, cuticular fractures were detected in both carriers and patients, but these alterations were much more prominent in the hair follicles of patients. In addition, erosions on the surface of the cuticle and local deep cavities just under the cuticular level were observed only in patients. Indistinct cuticular pattern, pores on the cuticular surface, and presence of concavities on the hair follicle were also detected in patients in later stages of the disease. According to our results, progression of the disease increased the alterations on hair structure. We suggest that ultra-structural alterations observed in hair samples might be due to oxidative stress caused by deficient frataxin expression in mitochondria.
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Affiliation(s)
- F Pinar Turkmenoglu
- Department of Pharmaceutical Botany, Faculty of Pharmacy, Hacettepe University, Ankara, Turkey
| | - U Baran Kasirga
- Department of Anatomy, Faculty of Medicine, Maltepe University, Ankara, Turkey
| | - H Hamdi Celik
- Department of Anatomy, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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19
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Pinto RB, Schneider ACR, da Silveira TR. Cirrhosis in children and adolescents: An overview. World J Hepatol 2015; 7:392-405. [PMID: 25848466 PMCID: PMC4381165 DOI: 10.4254/wjh.v7.i3.392] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/10/2014] [Accepted: 01/09/2015] [Indexed: 02/06/2023] Open
Abstract
Several conditions, especially chronic liver diseases, can lead to cirrhosis in children and adolescents. Most cases in clinical practice are caused by similar etiologies. In infants, cirrhosis is most often caused by biliary atresia and genetic-metabolic diseases, while in older children, it tends to result from autoimmune hepatitis, Wilson's disease, alpha-1-antitrypsin deficiency and primary sclerosing cholangitis. The symptoms of cirrhosis in children and adolescents are similar to those of adults. However, in pediatric patients, the first sign of cirrhosis is often poor weight gain. The complications of pediatric cirrhosis are similar to those observed in adult patients, and include gastrointestinal bleeding caused by gastroesophageal varices, ascites and spontaneous bacterial peritonitis. In pediatric patients, special attention should be paid to the nutritional alterations caused by cirrhosis, since children and adolescents have higher nutritional requirements for growth and development. Children and adolescents with chronic cholestasis are at risk for several nutritional deficiencies. Malnutrition can have severe consequences for both pre- and post-liver transplant patients. The treatment of cirrhosis-induced portal hypertension in children and adolescents is mostly based on methods developed for adults. The present article will review the diagnostic and differential diagnostic aspects of end-stage liver disease in children, as well as the major treatment options for this condition.
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Affiliation(s)
- Raquel Borges Pinto
- Raquel Borges Pinto, Pediatric Gastroenterology Unit, Hospital da Criança Conceição, Porto Alegre 91340 480, Rio Grande do Sul, Brazil
| | - Ana Claudia Reis Schneider
- Raquel Borges Pinto, Pediatric Gastroenterology Unit, Hospital da Criança Conceição, Porto Alegre 91340 480, Rio Grande do Sul, Brazil
| | - Themis Reverbel da Silveira
- Raquel Borges Pinto, Pediatric Gastroenterology Unit, Hospital da Criança Conceição, Porto Alegre 91340 480, Rio Grande do Sul, Brazil
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20
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Schadauer F, Geiss AF, Srajer J, Siebenhofer B, Frank P, Reiner-Rozman C, Ludwig B, Richter OMH, Nowak C, Naumann RLC. Silica nanoparticles for the oriented encapsulation of membrane proteins into artificial bilayer lipid membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2511-2516. [PMID: 25670233 DOI: 10.1021/la504417j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
An artificial bilayer lipid membrane system is presented, featuring the oriented encapsulation of membrane proteins in a functionally active form. Nickel nitrilo-triacetic acid-functionalized silica nanoparticles, of a diameter of around 25 nm, are used to attach the proteins via a genetically engineered histidine tag in a uniform orientation. Subsequently, the proteins are reconstituted within a phospholipid bilayer, formed around the particles by in situ dialysis to form so-called proteo-lipobeads (PLBs). With a final size of about 50 nm, the PLBs can be employed for UV/vis spectroscopy studies, particularly of multiredox center proteins, because the effects of light scattering are negligible. As a proof of concept, we use cytochrome c oxidase (CcO) from P. denitrificans with the his tag genetically engineered to subunit I. In this orientation, the P side of CcO is directed to the outside and hence electron transfer can be initiated by reduced cytochrome c (cc). UV/vis measurements are used in order to determine the occupancy by CcO molecules encapsulated in the lipid bilayer as well as the kinetics of electron transfer between CcO and cc. The kinetic data are analyzed in terms of the Michaelis-Menten kinetics showing that the turnover rate of CcO is significantly decreased compared to that of solubilized protein, whereas the binding characteristics are improved. The data demonstrate the suitability of PLBs for functional cell-free bioassays of membrane proteins.
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Affiliation(s)
- Florian Schadauer
- Austrian Institute of Technology GmbH , AIT, Donau-City Str. 1, 1220 Vienna, Austria
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21
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Diagnostic approach in infants and children with mitochondrial diseases. Pediatr Neonatol 2015; 56:7-18. [PMID: 25151629 DOI: 10.1016/j.pedneo.2014.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 03/27/2014] [Indexed: 01/06/2023] Open
Abstract
Mitochondrial diseases are a heterogeneous group of disorders affecting energy production in the human body. The diagnosis of mitochondrial diseases represents a challenge to clinicians, especially for pediatric cases, which show enormous variation in clinical presentations, as well as biochemical and genetic complexity. Different consensus diagnostic criteria for mitochondrial diseases in infants and children are available. The lack of standardized diagnostic criteria poses difficulties in evaluating diagnostic methodologies. Even though there are many diagnostic tools, none of them are sensitive enough to make a confirmative diagnosis without being used in combination with other tools. The current approach to diagnosing and classifying mitochondrial diseases incorporates clinical, biochemical, neuroradiological findings, and histological criteria, as well as DNA-based molecular diagnostic testing. The confirmation or exclusion of mitochondrial diseases remains a challenge in clinical practice, especially in cases with nonspecific clinical phenotypes. Therefore, follow-up evolution of clinical symptoms/signs and biochemical data is crucial. The purpose of this study is to review the molecular classification scheme and associated phenotypes in infants and children with mitochondrial diseases, in addition to providing an overview of the basic biochemical reactions and genetic characteristics in the mitochondrion, clinical manifestations, and diagnostic methods. A diagnostic algorithm for identifying mitochondrial disorders in pediatric neurology patients is proposed.
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22
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Ajroud-Driss S, Fecto F, Ajroud K, Lalani I, Calvo SE, Mootha VK, Deng HX, Siddique N, Tahmoush AJ, Heiman-Patterson TD, Siddique T. Mutation in the novel nuclear-encoded mitochondrial protein CHCHD10 in a family with autosomal dominant mitochondrial myopathy. Neurogenetics 2014; 16:1-9. [PMID: 25193783 DOI: 10.1007/s10048-014-0421-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/21/2014] [Indexed: 12/11/2022]
Abstract
Mitochondrial myopathies belong to a larger group of systemic diseases caused by morphological or biochemical abnormalities of mitochondria. Mitochondrial disorders can be caused by mutations in either the mitochondrial or nuclear genome. Only 5% of all mitochondrial disorders are autosomal dominant. We analyzed DNA from members of the previously reported Puerto Rican kindred with an autosomal dominant mitochondrial myopathy (Heimann-Patterson et al. 1997). Linkage analysis suggested a putative locus on the pericentric region of the long arm of chromosome 22 (22q11). Using the tools of integrative genomics, we established chromosome 22 open reading frame 16 (C22orf16) (later designated as CHCHD10) as the only high-scoring mitochondrial candidate gene in our minimal candidate region. Sequence analysis revealed a double-missense mutation (R15S and G58R) in cis in CHCHD10 which encodes a coiled coil-helix-coiled coil-helix protein of unknown function. These two mutations completely co-segregated with the disease phenotype and were absent in 1,481 Caucasian and 80 Hispanic (including 32 Puerto Rican) controls. Expression profiling showed that CHCHD10 is enriched in skeletal muscle. Mitochondrial localization of the CHCHD10 protein was confirmed using immunofluorescence in cells expressing either wild-type or mutant CHCHD10. We found that the expression of the G58R, but not the R15S, mutation induced mitochondrial fragmentation. Our findings identify a novel gene causing mitochondrial myopathy, thereby expanding the spectrum of mitochondrial myopathies caused by nuclear genes. Our findings also suggest a role for CHCHD10 in the morphologic remodeling of the mitochondria.
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Affiliation(s)
- Senda Ajroud-Driss
- Division of Neuromuscular Medicine, The Ken and Ruth Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA,
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23
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Abstract
We report the case of a novel mitochondrial DNA mutation in the MT-ATP8 gene in an infant with tetralogy of Fallot. Next-generation sequencing was applied to sequence whole mitochondrial DNA of the patient. A known Leber's hereditary optic neuropathy-associated mutation (G9804A), a heteroplasmic T7501C mutation (17%), and a novel C8481 T Pro > Leu missense mutation in the MT-ATP8 gene was identified.
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24
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Pandey S, Singh A, Kumar P, Chaudhari A, Nareshkumar G. Probiotic Escherichia coli CFR 16 producing pyrroloquinoline quinone (PQQ) ameliorates 1,2-dimethylhydrazine-induced oxidative damage in colon and liver of rats. Appl Biochem Biotechnol 2014; 173:775-86. [PMID: 24718737 DOI: 10.1007/s12010-014-0897-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/30/2014] [Indexed: 01/10/2023]
Abstract
Inflammation of the gastrointestinal tract is associated with reactive oxygen species (ROS) genesis. Alleviation of oxidative stress is achieved by using antioxidants and probiotics. Present study investigates a synergistic effect of the probiotic Escherichia coli CFR 16 containing Vitreoscilla haemoglobin gene (vgb), green fluorescent protein (gfp) gene and pyrroloquinoline quinone (pqq) gene cluster on oxidative stress induced by 1,2-dimethylhydrazine (DMH). Adult virgin Charles foster male rats (3-4 months) weighing 200-250 g were administered with DMH (25 mg/kg body weight, s.c.) twice a week for eight consecutive weeks. Rats receiving only DMH dose showed increased lipid peroxidation in liver and intestinal tissues with reduced activity of antioxidant enzymes, i.e. superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Oral dose of E. coli CFR 16::vgb-gfp harbouring pqq gene cluster increased rat faecal PQQ concentration by twofold, reduced lipid peroxidation and retained SOD, CAT and GPx activities close to normal levels in liver and colonic tissues following DMH treatment. In addition, significant protection was found in colonic histological sections of these rat groups. This study demonstrates a protective efficacy in the following order: E. coli CFR 16 < E. coli CFR 16::vgb-gfp < vitamin C = PQQ < E. coli CFR 16::vgb-gfp (pqq).
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Affiliation(s)
- Sumeet Pandey
- Department of Biochemistry, Faculty of Science, Maharaja Sayajirao University of Baroda, Vadodara, 390002, India
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25
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Chen HL, Bernard CS, Hubert P, My L, Zhang CC. Fluorescence resonance energy transfer based on interaction of PII and PipX proteins provides a robust and specific biosensor for 2-oxoglutarate, a central metabolite and a signalling molecule. FEBS J 2014; 281:1241-55. [DOI: 10.1111/febs.12702] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/22/2013] [Accepted: 12/17/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Hai-Lin Chen
- Laboratoire de Chimie Bactérienne; UMR 7283; Aix-Marseille Université and CNRS; France
| | - Christophe S. Bernard
- Laboratoire de Chimie Bactérienne; UMR 7283; Aix-Marseille Université and CNRS; France
| | - Pierre Hubert
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires; UMR 7255; Aix-Marseille Université and CNRS; France
| | - Laetitia My
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires; UMR 7255; Aix-Marseille Université and CNRS; France
| | - Cheng-Cai Zhang
- Laboratoire de Chimie Bactérienne; UMR 7283; Aix-Marseille Université and CNRS; France
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26
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Bonnen PE, Yarham JW, Besse A, Wu P, Faqeih EA, Al-Asmari AM, Saleh MAM, Eyaid W, Hadeel A, He L, Smith F, Yau S, Simcox EM, Miwa S, Donti T, Abu-Amero KK, Wong LJ, Craigen WJ, Graham BH, Scott KL, McFarland R, Taylor RW. Mutations in FBXL4 cause mitochondrial encephalopathy and a disorder of mitochondrial DNA maintenance. Am J Hum Genet 2013; 93:471-81. [PMID: 23993193 DOI: 10.1016/j.ajhg.2013.07.017] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/12/2013] [Accepted: 07/17/2013] [Indexed: 12/12/2022] Open
Abstract
Nuclear genetic disorders causing mitochondrial DNA (mtDNA) depletion are clinically and genetically heterogeneous, and the molecular etiology remains undiagnosed in the majority of cases. Through whole-exome sequencing, we identified recessive nonsense and splicing mutations in FBXL4 segregating in three unrelated consanguineous kindreds in which affected children present with a fatal encephalopathy, lactic acidosis, and severe mtDNA depletion in muscle. We show that FBXL4 is an F-box protein that colocalizes with mitochondria and that loss-of-function and splice mutations in this protein result in a severe respiratory chain deficiency, loss of mitochondrial membrane potential, and a disturbance of the dynamic mitochondrial network and nucleoid distribution in fibroblasts from affected individuals. Expression of the wild-type FBXL4 transcript in cell lines from two subjects fully rescued the levels of mtDNA copy number, leading to a correction of the mitochondrial biochemical deficit. Together our data demonstrate that mutations in FBXL4 are disease causing and establish FBXL4 as a mitochondrial protein with a possible role in maintaining mtDNA integrity and stability.
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Affiliation(s)
- Penelope E Bonnen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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27
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Craigen WJ, Graham BH, Wong LJ, Scaglia F, Lewis RA, Bonnen PE. Exome sequencing of a patient with suspected mitochondrial disease reveals a likely multigenic etiology. BMC MEDICAL GENETICS 2013; 14:83. [PMID: 23947751 PMCID: PMC3751849 DOI: 10.1186/1471-2350-14-83] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 08/06/2013] [Indexed: 12/04/2022]
Abstract
Background The clinical features of mitochondrial disease are complex and highly variable, leading to challenges in establishing a specific diagnosis. Despite being one of the most commonly occurring inherited genetic diseases with an incidence of 1/5000, ~90% of these complex patients remain without a DNA-based diagnosis. We report our efforts to identify the pathogenetic cause for a patient with typical features of mitochondrial disease including infantile cataracts, CPEO, ptosis, progressive distal muscle weakness, and ataxia who carried a diagnosis of mitochondrial disease for over a decade. Methods Whole exome sequencing and bioinformatic analysis of these data were conducted on the proband. Results Exome sequencing studies showed a homozygous splice site mutation in SETX, which is known to cause Spinocerebellar Ataxia, Autosomal Recessive 1 (SCAR1). Additionally a missense mutation was identified in a highly conserved position of the OCRL gene, which causes Lowe Syndrome and Dent Disease 2. Conclusions This patient’s complex phenotype reflects a complex genetic etiology in which no single gene explained the complete clinical presentation. These genetic studies reveal that this patient does not have mitochondrial disease but rather a genocopy caused by more than one mutant locus. This study demonstrates the benefit of exome sequencing in providing molecular diagnosis to individuals with complex clinical presentations.
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Affiliation(s)
- William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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28
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Siebel S, Solomon B. Mitochondrial Factors and VACTERL Association-Related Congenital Malformations. Mol Syndromol 2013; 4:63-73. [PMID: 23653577 PMCID: PMC3638779 DOI: 10.1159/000346301] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
VACTERL/VATER association is a group of congenital malformations characterized by at least 3 of the following findings: vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities. To date, no unifying etiology for VACTERL/VATER association has been established, and there is strong evidence for causal heterogeneity. VACTERL/VATER association has many overlapping characteristics with other congenital disorders that involve multiple malformations. In addition to these other conditions, some of which have known molecular causes, certain aspects of VACTERL/VATER association have similarities with the manifestations of disorders caused by mitochondrial dysfunction. Mitochondrial dysfunction can result from a number of distinct causes and can clinically manifest in diverse presentations; accurate diagnosis can be challenging. Case reports of individuals with VACTERL association and confirmed mitochondrial dysfunction allude to the possibility of mitochondrial involvement in the pathogenesis of VACTERL/VATER association. Further, there is biological plausibility involving mitochondrial dysfunction as a possible etiology related to a diverse group of congenital malformations, including those seen in at least a subset of individuals with VACTERL association.
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Affiliation(s)
| | - B.D. Solomon
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Md., USA
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29
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Al-Ettribi GM, Effat LK, El-Bassyouni HT, Zaki MS, Shanab G, Karim AM. Clinical and molecular findings in eight Egyptian patients with suspected mitochondrial disorders and optic atrophy. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2013. [DOI: 10.1016/j.ejmhg.2012.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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30
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Kogure H, Hikawa Y, Hagihara M, Tochio N, Koshiba S, Inoue Y, Güntert P, Kigawa T, Yokoyama S, Nameki N. Solution structure and siRNA-mediated knockdown analysis of the mitochondrial disease-related protein C12orf65. Proteins 2012; 80:2629-42. [DOI: 10.1002/prot.24152] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/27/2012] [Accepted: 07/05/2012] [Indexed: 01/17/2023]
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Hardeland R. Neurobiology, pathophysiology, and treatment of melatonin deficiency and dysfunction. ScientificWorldJournal 2012; 2012:640389. [PMID: 22629173 PMCID: PMC3354573 DOI: 10.1100/2012/640389] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 01/05/2012] [Indexed: 12/13/2022] Open
Abstract
Melatonin is a highly pleiotropic signaling molecule, which is released as a hormone of the pineal gland predominantly during night. Melatonin secretion decreases during aging. Reduced melatonin levels are also observed in various diseases, such as types of dementia, some mood disorders, severe pain, cancer, and diabetes type 2. Melatonin dysfunction is frequently related to deviations in amplitudes, phasing, and coupling of circadian rhythms. Gene polymorphisms of melatonin receptors and circadian oscillator proteins bear risks for several of the diseases mentioned. A common symptom of insufficient melatonin signaling is sleep disturbances. It is necessary to distinguish between symptoms that are curable by short melatonergic actions and others that require extended actions during night. Melatonin immediate release is already effective, at moderate doses, for reducing difficulties of falling asleep or improving symptoms associated with poorly coupled circadian rhythms, including seasonal affective and bipolar disorders. For purposes of a replacement therapy based on longer-lasting melatonergic actions, melatonin prolonged release and synthetic agonists have been developed. Therapies with melatonin or synthetic melatonergic drugs have to consider that these agents do not only act on the SCN, but also on numerous organs and cells in which melatonin receptors are also expressed.
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Affiliation(s)
- Rüdiger Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, Georg August University, 37073 Göttingen, Germany.
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Iyer S, Xiao E, Alsayegh K, Eroshenko N, Riggs MJ, Bennett JP, Rao RR. Mitochondrial gene replacement in human pluripotent stem cell-derived neural progenitors. Gene Ther 2012; 19:469-75. [PMID: 21918550 PMCID: PMC11071659 DOI: 10.1038/gt.2011.134] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 07/13/2011] [Accepted: 08/05/2011] [Indexed: 12/22/2022]
Abstract
Human pluripotent stem cell-derived neural progenitor (hNP) cells are an excellent resource for understanding early neural development and neurodegenerative disorders. Given that many neurodegenerative disorders can be correlated with defects in the mitochondrial genome, optimal utilization of hNP cells requires an ability to manipulate and monitor changes in the mitochondria. Here, we describe a novel approach that uses recombinant human mitochondrial transcription factor A (rhTFAM) protein to transfect and express a pathogenic mitochondrial genome (mtDNA) carrying the G11778A mutation associated with Leber's hereditary optic neuropathy (LHON) disease, into dideoxycytidine (ddC)-treated hNPs. Treatment with ddC reduced endogenous mtDNA and gene expression, without loss of hNP phenotypic markers. Entry of G11778A mtDNA complexed with the rhTFAM was observed in mitochondria of ddC-hNPs. Expression of the pathogenic RNA was confirmed by restriction enzyme analysis of the SfaN1-digested cDNA. On the basis of the expression of neuron-specific class III beta-tubulin, neuronal differentiation occurred. Our results show for the first time that pathogenic mtDNA can be introduced and expressed into hNPs without loss of phenotype or neuronal differentiation potential. This mitochondrial gene replacement technology allows for creation of in vitro stem cell-based models useful for understanding neuronal development and treatment of neurodegenerative disorders.
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Affiliation(s)
- S Iyer
- Center for the Study of Biological Complexity, Life Sciences Program, Virginia Commonwealth University, Richmond, VA, USA
| | - E Xiao
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, USA
- Current address: Neuroimaging Core; Genes, Cognition, and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
| | - K Alsayegh
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - N Eroshenko
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, USA
- School of Engineering and Applied Sciences, Harvard University, Boston, MA, USA
| | - MJ Riggs
- Integrated Life Sciences Program, Virginia Commonwealth University, Richmond, VA, USA
| | - JP Bennett
- Parkinson’s Disease Center, Virginia Commonwealth University, Richmond, VA, USA
- Department of Neurology, Virginia Commonwealth University, Richmond, VA, USA
| | - RR Rao
- Center for the Study of Biological Complexity, Life Sciences Program, Virginia Commonwealth University, Richmond, VA, USA
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, USA
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, USA
- Integrated Life Sciences Program, Virginia Commonwealth University, Richmond, VA, USA
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Bayat V, Thiffault I, Jaiswal M, Tétreault M, Donti T, Sasarman F, Bernard G, Demers-Lamarche J, Dicaire MJ, Mathieu J, Vanasse M, Bouchard JP, Rioux MF, Lourenco CM, Li Z, Haueter C, Shoubridge EA, Graham BH, Brais B, Bellen HJ. Mutations in the mitochondrial methionyl-tRNA synthetase cause a neurodegenerative phenotype in flies and a recessive ataxia (ARSAL) in humans. PLoS Biol 2012; 10:e1001288. [PMID: 22448145 PMCID: PMC3308940 DOI: 10.1371/journal.pbio.1001288] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 02/08/2012] [Indexed: 11/23/2022] Open
Abstract
The study of Drosophila neurodegenerative mutants combined with genetic and biochemical analyses lead to the identification of multiple complex mutations in 60 patients with a novel form of ataxia/leukoencephalopathy. An increasing number of genes required for mitochondrial biogenesis, dynamics, or function have been found to be mutated in metabolic disorders and neurological diseases such as Leigh Syndrome. In a forward genetic screen to identify genes required for neuronal function and survival in Drosophila photoreceptor neurons, we have identified mutations in the mitochondrial methionyl-tRNA synthetase, Aats-met, the homologue of human MARS2. The fly mutants exhibit age-dependent degeneration of photoreceptors, shortened lifespan, and reduced cell proliferation in epithelial tissues. We further observed that these mutants display defects in oxidative phosphorylation, increased Reactive Oxygen Species (ROS), and an upregulated mitochondrial Unfolded Protein Response. With the aid of this knowledge, we identified MARS2 to be mutated in Autosomal Recessive Spastic Ataxia with Leukoencephalopathy (ARSAL) patients. We uncovered complex rearrangements in the MARS2 gene in all ARSAL patients. Analysis of patient cells revealed decreased levels of MARS2 protein and a reduced rate of mitochondrial protein synthesis. Patient cells also exhibited reduced Complex I activity, increased ROS, and a slower cell proliferation rate, similar to Drosophila Aats-met mutants. Neurodegenerative diseases, as a group, are relatively common and often devastating to those who suffer from them. Key insights are emerging from the study of homologues of identified human disease-causing genes in model organisms such as fruit flies, worms, and mice. In this study, we used the fruit fly to identify novel neurodegeneration-causing mutations and identified the Aats-met gene, whose protein product is involved in mitochondrial translation. We found that mutations in this gene cause neurodegeneration, impaired mitochondrial activity, and elevated oxidative stress. We were able to attenuate these defects with antioxidants like Vitamin E. We also determined that unusual duplications in the homologous human gene, MARS2, were responsible for a novel type of progressive ataxia found in some French Canadian families. Cells taken from these patients have many of the characteristic defects observed in flies, showing that the fly mutants can be used to further explore disease mechanisms and test potential treatments.
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Affiliation(s)
- Vafa Bayat
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, United States of America
| | - Isabelle Thiffault
- Laboratoire de Neurogénétique de la Motricité, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Department of Human Genetics, Montreal Neurological Institute–McGill University, Montréal, Québec, Canada
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Martine Tétreault
- Laboratoire de Neurogénétique de la Motricité, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Taraka Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Florin Sasarman
- Department of Human Genetics, Montreal Neurological Institute–McGill University, Montréal, Québec, Canada
| | - Geneviève Bernard
- Laboratoire de Neurogénétique de la Motricité, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Julie Demers-Lamarche
- Laboratoire de Neurogénétique de la Motricité, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Marie-Josée Dicaire
- Laboratoire de Neurogénétique de la Motricité, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Jean Mathieu
- Clinique des Maladies Neuromusculaires, Centre de Santé et de Services Sociaux de Jonquière, Saguenay, Québec, Canada
| | - Michel Vanasse
- Clinique des Maladies Neuromusculaires, Centre Hospitalier Universitaire Sainte-Justine, Montréal, Québec, Canada
| | - Jean-Pierre Bouchard
- Service de Neurologie, Centre Hospitalier Affilié Universitaire de Québec–Hôpital de l'Enfant-Jésus, Université Laval, Québec, Québec, Canada
| | - Marie-France Rioux
- Service de Neurologie, Centre hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Charles M. Lourenco
- Department of Medical Genetics, University of São Paulo, Ribeirao Preto–São Paulo, Brazil
| | - Zhihong Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Claire Haueter
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Eric A. Shoubridge
- Department of Human Genetics, Montreal Neurological Institute–McGill University, Montréal, Québec, Canada
| | - Brett H. Graham
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Bernard Brais
- Laboratoire de Neurogénétique de la Motricité, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
- Department of Human Genetics, Montreal Neurological Institute–McGill University, Montréal, Québec, Canada
- Clinique des Maladies Neuromusculaires, Centre de Santé et de Services Sociaux de Jonquière, Saguenay, Québec, Canada
- Clinique des Maladies Neuromusculaires, Centre Hospitalier Universitaire Sainte-Justine, Montréal, Québec, Canada
- * E-mail: (BB); (HJB)
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (BB); (HJB)
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Abstract
Mitochondria are essential organelles with multiple functions, the most well known being the production of adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS). The mitochondrial diseases are defined by impairment of OXPHOS. They are a diverse group of diseases that can present in virtually any tissue in either adults or children. Here we review the main molecular mechanisms of mitochondrial diseases, as presently known. A number of disease-causing genetic defects, either in the nuclear genome or in the mitochondria's own genome, mitochondrial DNA (mtDNA), have been identified. The most classical genetic defect causing mitochondrial disease is a mutation in a gene encoding a structural OXPHOS subunit. However, mitochondrial diseases can also arise through impaired mtDNA maintenance, defects in mitochondrial translation factors, and various more indirect mechanisms. The putative consequences of mitochondrial dysfunction on a cellular level are discussed.
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Affiliation(s)
- Emil Ylikallio
- Research Programs Unit, Molecular Neurology, Biomedicum-Helsinki, University of Helsinki, Finland.
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Salmi H, Leonard JV, Rahman S, Lapatto R. Plasma thiol status is altered in children with mitochondrial diseases. Scandinavian Journal of Clinical and Laboratory Investigation 2012; 72:152-7. [PMID: 22208644 DOI: 10.3109/00365513.2011.646299] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE This study was undertaken to investigate thiol metabolism as a marker of oxidative stress and antioxidative defence capacity in a cohort of children with biochemically and/or genetically confirmed mitochondrial disease. Previous studies suggest that lower glutathione levels, which have been shown to further compromise mitochondrial function, may occur in these diseases. Better understanding of the pathogenesis of mitochondrial diseases is important in order to improve their treatment. METHODS We studied plasma and erythrocyte glutathione and cysteine levels, the activities of erythrocyte glutathione peroxidase (GPx), glutathione reductase (GR), glucose 6-phosphate dehydrogenase G6PDH) and glutathione S-transferase (GST), as well as the levels of erythrocyte thiobarbituric acid-reactive species (TBA-RS) and protein carbonyls in 10 children with a biochemical and/or genetic diagnosis of mitochondrial disease and six controls. RESULTS Levels of reduced cysteine (CYSH) as well as reduced to oxidised cysteine ratio were lower in plasma of patients with mitochondrial diseases (p = 0.008 and p = 0.02, respectively). Plasma levels of reduced glutathione (GSH) were low in patients with mitochondrial diseases, mostly below the detection limit. We did not detect significant differences in erythrocyte thiols or glutathione-related enzyme activities. CONCLUSION Plasma thiols and their redox state are altered in patients with mitochondrial diseases, suggesting an increase in oxidative stress and depletion of antioxidant supplies. If confirmed in further studies, this relative thiol deficiency could be an important factor in the pathophysiology of mitochondrial diseases.
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Affiliation(s)
- Heli Salmi
- University of Helsinki, Hospital for Children and Adolescents, Helsinki, Finland.
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Miles MV, Miles L, Horn PS, DeGrauw TJ. Enzyme inducing antiepileptic drugs are associated with mitochondrial proliferation and increased cytochrome c oxidase activity in muscle of children with epilepsy. Epilepsy Res 2012; 98:76-87. [DOI: 10.1016/j.eplepsyres.2011.08.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 08/19/2011] [Accepted: 08/27/2011] [Indexed: 10/17/2022]
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Tang PH, Miles MV. Measurement of oxidized and reduced coenzyme Q in biological fluids, cells, and tissues: an HPLC-EC method. Methods Mol Biol 2012; 837:149-168. [PMID: 22215546 DOI: 10.1007/978-1-61779-504-6_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Direct measure of coenzyme Q (CoQ) in biological specimens may provide important advantages. Precise and selective high-performance liquid chromatography (HPLC) methods with electrochemical (EC) detection have been developed for the measurement of reduced (ubiquinol) and oxidized (ubiquinone) CoQ in biological fluids, cells, and tissues. EC detection is preferred for measurement of CoQ because of its high sensitivity. Reduced and oxidized CoQ are first extracted from biological specimens using 1-propanol. After centrifugation, the 1-propanol supernatant is directly injected into HPLC and monitored at a dual-electrode. The EC reactions occur at the electrode surface. The first electrode transforms ubiquinone into ubiquinol, and the second electrode measures the current produced by the oxidation of the hydroquinone group of ubiquinol. The methods described provide rapid, precise, and simple procedures for determination of reduced and oxidized CoQ in biological fluids, cells, and tissues. The methods have been successfully adapted to meet regulatory requirements for clinical laboratories, and have been proven reliable for analysis of clinical and research samples for clinical trials and animal studies involving large numbers of specimens.
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Affiliation(s)
- Peter H Tang
- Division of Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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The screening of inborn errors of metabolism in sick Chinese infants by tandem mass spectrometry and gas chromatography/mass spectrometry. Clin Chim Acta 2011; 412:1270-4. [DOI: 10.1016/j.cca.2011.03.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 03/27/2011] [Accepted: 03/28/2011] [Indexed: 11/20/2022]
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Mindikoglu AL, King D, Magder LS, Ozolek JA, Mazariegos GV, Shneider BL. Valproic acid-associated acute liver failure in children: case report and analysis of liver transplantation outcomes in the United States. J Pediatr 2011; 158:802-7. [PMID: 21167499 PMCID: PMC3075355 DOI: 10.1016/j.jpeds.2010.10.033] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 09/24/2010] [Accepted: 10/21/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To determine whether valproic acid (VPA)-associated acute liver failure (ALF; VPA-ALF) explains the poor outcomes after liver transplantation (LT) in children. STUDY DESIGN Organ Procurement and Transplantation Network data of pediatric patients who underwent LT for VPA-ALF and ALF caused by other drugs (non-VPA-drug-induced acute liver failure [DIALF]) were analyzed. Pre- and post-transplant variables and post-LT survival were compared between VPA-ALF and non-VPA-DIALF. RESULTS Seventeen children were transplanted for VPA-ALF. Of the 17 children, 82% died within 1 year of LT. Pre- and post-transplant parameters of VPA versus non-VPA-DIALF were comparable with two exceptions. The median alanine aminotransferase level at transplant was remarkably lower in VPA-ALF compared with non-VPA-DIALF (45 versus 1179 IU/L, P = .004). One-year survival probability was worse in VPA-ALF than non-VPA-DIALF (20% versus 69%, P < .0001). Median post-LT survival time for VPA-ALF was 2.8 months. CONCLUSION Children who underwent LT for VPA-ALF had a significantly lower survival probability than children with non-VPA-DIALF. Current data suggest that VPA-ALF in children represents an "unmasking" of mitochondrial disease. VPA-ALF should be a contraindication for LT, even in the absence of a documented mitochondrial disease.
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Affiliation(s)
- Ayse L. Mindikoglu
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, MD
| | - Dale King
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Laurence S. Magder
- Department of Epidemiology and Public Health, Division of Biostatistics and Bioinformatics, University of Maryland School of Medicine, Baltimore, MD
| | - John A. Ozolek
- Department of Pathology, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - George V. Mazariegos
- Hillman Center for Pediatric Transplantation, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Benjamin L. Shneider
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA
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Reinhold R, Bareth B, Balleininger M, Wissel M, Rehling P, Mick DU. Mimicking a SURF1 allele reveals uncoupling of cytochrome c oxidase assembly from translational regulation in yeast. Hum Mol Genet 2011; 20:2379-93. [PMID: 21470975 DOI: 10.1093/hmg/ddr145] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Defects in mitochondrial energy metabolism lead to severe human disorders, mainly affecting tissues especially dependent on oxidative phosphorylation, such as muscle and brain. Leigh Syndrome describes a severe encephalomyopathy in infancy, frequently caused by mutations in SURF1. SURF1, termed Shy1 in Saccharomyces cerevisiae, is a conserved assembly factor for the terminal enzyme of the respiratory chain, cytochrome c oxidase. Although the molecular function of SURF1/Shy1 is still enigmatic, loss of function leads to cytochrome c oxidase deficiency and reduced expression of the central subunit Cox1 in yeast. Here, we provide insights into the molecular mechanisms leading to disease through missense mutations in codons of the most conserved amino acids in SURF1. Mutations affecting G(124) do not compromise import of the SURF1 precursor protein but lead to fast turnover of the mature protein within the mitochondria. Interestingly, an Y(274)D exchange neither affects stability nor localization of the protein. Instead, SURF1(Y274D) accumulates in a 200 kDa cytochrome c oxidase assembly intermediate. Using yeast as a model, we demonstrate that the corresponding Shy1(Y344D) is able to overcome the stage where cytochrome c oxidase assembly links to the feedback regulation of mitochondrial Cox1 expression. However, Shy1(Y344D) impairs the assembly at later steps, most apparent at low temperature and exhibits a dominant-negative phenotype upon overexpression. Thus, exchanging the conserved tyrosine (Y(344)) with aspartate in yeast uncouples translational regulation of Cox1 from cytochrome c oxidase assembly and provides evidence for the dual functionality of Shy1.
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Affiliation(s)
- Robert Reinhold
- Abteilung für Biochemie II, Universität Göttingen, D-37073 Göttingen, Germany
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Long X, Zhang J, Zhang Y, Yao J, Cai Z, Yang P. Nano-LC-MS/MS based proteomics of hepatocellular carcinoma cells compared to Chang liver cells and tanshinone IIA induction. MOLECULAR BIOSYSTEMS 2011; 7:1728-41. [DOI: 10.1039/c0mb00343c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Lamla M, Seliger H, Kaufmann D. Differences in uptake, localization, and processing of PNAs modified by COX VIII pre-sequence peptide and by triphenylphoshonium cation into mitochondria of tumor cells. Drug Deliv 2010; 17:263-71. [PMID: 20307248 DOI: 10.3109/10717541003702777] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Two approaches to target PNAs (peptide nucleic acids) into mitochondria of HeLa cells were compared. In the first, PNA was modified with the lipophilic cation TPP. TPP-PNA accumulated rapidly within mitochondria driven by the membrane potential. It was found to be associated mainly with the mitochondrial membranes. In the second approach the COX VIII pre-sequence peptide was added to the PNA resulting in slow uptake of the peptide-PNA into the mitochondrial matrix. Whereas the amount of the uptake was lower, peptide-PNA was processed intramitochondrially in contrast to the TPP-PNA. Using the Chariot system to cross the cell membrane of HeLa cells, the uptake of peptide-PNA into the mitochondria was demonstrated. If a matrix localization of the free PNA is a pre-requisite for the PNA interaction with mitochondrial DNA, the coupling PNA with an appropriate peptide seems to be the better strategy.
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Affiliation(s)
- Markus Lamla
- Research Group Chemical Function in Biosystems, University of Ulm, Albert Einstein Allee 11, D 89081 Ulm, Germany
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Lactic acid induces aberrant amyloid precursor protein processing by promoting its interaction with endoplasmic reticulum chaperone proteins. PLoS One 2010; 5:e13820. [PMID: 21072203 PMCID: PMC2972223 DOI: 10.1371/journal.pone.0013820] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 10/06/2010] [Indexed: 01/17/2023] Open
Abstract
Background Lactic acid, a natural by-product of glycolysis, is produced at excess levels in response to impaired mitochondrial function, high-energy demand, and low oxygen availability. The enzyme involved in the production of β-amyloid peptide (Aβ) of Alzheimer's disease, BACE1, functions optimally at lower pH, which led us to investigate a potential role of lactic acid in the processing of amyloid precursor protein (APP). Methodology/Principal Findings Lactic acid increased levels of Aβ40 and 42, as measured by ELISA, in culture medium of human neuroblastoma cells (SH-SY5Y), whereas it decreased APP metabolites, such as sAPPα. In cell lysates, APP levels were increased and APP was found to interact with ER-chaperones in a perinuclear region, as determined by co-immunoprecipitation and fluorescence microscopy studies. Lactic acid had only a very modest effect on cellular pH, did increase the levels of ER chaperones Grp78 and Grp94 and led to APP aggregate formation reminiscent of aggresomes. Conclusions/Significance These findings suggest that sustained elevations in lactic acid levels could be a risk factor in amyloidogenesis related to Alzheimer's disease through enhanced APP interaction with ER chaperone proteins and aberrant APP processing leading to increased generation of amyloid peptides and APP aggregates.
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Chi CS, Lee HF, Tsai CR, Lee HJ, Chen LH. Clinical manifestations in children with mitochondrial diseases. Pediatr Neurol 2010; 43:183-9. [PMID: 20691940 DOI: 10.1016/j.pediatrneurol.2010.04.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 03/24/2010] [Accepted: 04/27/2010] [Indexed: 11/18/2022]
Abstract
Mitochondrial diseases comprise a group of complex and heterogeneous genetic disorders. Variable clinical features present a major challenge in pediatric diagnoses. From January 1984-June 2009, 69 patients were diagnosed with either syndromic mitochondrial diseases or nonsyndromic mitochondrial diseases. Clinical manifestations, laboratory findings, and histopathologic results differentiating syndromic from nonsyndromic mitochondrial diseases were analyzed by chi(2) test, with cutoff significance at P = 0.05. The commonest clinical manifestation involved central nervous system signs (88.4%). A comparison of central nervous system signs in syndromic vs nonsyndromic mitochondrial diseases revealed significant differences in terms of headache, external ocular motility, and apnea (P < 0.05). A comparison of organ systems revealed a significant difference for signs of the cardiovascular system. Elevated initial blood lactate levels were evident in 40.6% of patients, and 84.8% produced abnormal results after oral glucose challenge. Ragged red fibers were observed in 51.6% of patients. The positive rate of mitochondrial gene mutation was 27.5%. Age and disease were directly related: the younger the age at initial disease onset, the higher the frequency of mortality and morbidity. Notorious variability in the presentation of mitochondrial diseases exists in all pediatric subspecialties. Greater familiarity with those signs will facilitate more accurate diagnoses.
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Affiliation(s)
- Ching-Shiang Chi
- Department of Pediatrics, Tungs' Taichung Metroharbor Hospital, Taichung, Taiwan, Republic of China
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Antonicka H, Østergaard E, Sasarman F, Weraarpachai W, Wibrand F, Pedersen AMB, Rodenburg RJ, van der Knaap MS, Smeitink JA, Chrzanowska-Lightowlers ZM, Shoubridge EA. Mutations in C12orf65 in patients with encephalomyopathy and a mitochondrial translation defect. Am J Hum Genet 2010; 87:115-22. [PMID: 20598281 DOI: 10.1016/j.ajhg.2010.06.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 05/20/2010] [Accepted: 06/04/2010] [Indexed: 10/19/2022] Open
Abstract
We investigated the genetic basis for a global and uniform decrease in mitochondrial translation in fibroblasts from patients in two unrelated pedigrees who developed Leigh syndrome, optic atrophy, and ophthalmoplegia. Analysis of the assembly of the oxidative phosphorylation complexes showed severe decreases of complexes I, IV, and V and a smaller decrease in complex III. The steady-state levels of mitochondrial mRNAs, tRNAs, and rRNAs were not reduced, nor were those of the mitochondrial translation elongation factors or the protein components of the mitochondrial ribosome. Using homozygosity mapping, we identified a 1 bp deletion in C12orf65 in one patient, and DNA sequence analysis showed a different 1 bp deletion in the second patient. Both mutations predict the same premature stop codon. C12orf65 belongs to a family of four mitochondrial class I peptide release factors, which also includes mtRF1a, mtRF1, and Ict1, all characterized by the presence of a GGQ motif at the active site. However, C12orf65 does not exhibit peptidyl-tRNA hydrolase activity in an in vitro assay with bacterial ribosomes. We suggest that it might play a role in recycling abortive peptidyl-tRNA species, released from the ribosome during the elongation phase of translation.
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Kwon HE, Lee JH, Lee YM, Kang HC, Lee JS, Kim HD. Iron deficiency in children with mitochondrial disease. Metab Brain Dis 2010; 25:185-9. [PMID: 20424904 DOI: 10.1007/s11011-010-9196-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2009] [Accepted: 08/27/2009] [Indexed: 10/19/2022]
Abstract
Mitochondrial disease is an energy metabolic disorder with various organ involvement. Iron is widely known to be one of the most important nutriments required for normal brain development and several essential metabolic functions. We retrospectively studied the laboratory data on iron deficiency (ID) in 69 children with mitochondrial respiratory chain complex (MRC) defects by biochemical enzyme assay using muscle tissue. We analyzed the differences between groups of mitochondrial disease based on the presence of ID. ID has higher prevalence in children with mitochondrial disease than in the normal population. There were 6 (9%) patients with low hemoglobin, 12 (17%) with low serum ferrtin, and 22 (32%) with low transferrin saturation levels among children with MRC defects. In comparisons between the ID and the non-ID group of MRC-defect patients, the frequency of MRC I defect was significantly higher in the ID group while that of MRC IV defect was higher in the non-ID group. Abnormal brain magnetic resonance imaging (MRI) findings were more frequently detected in the ID group. The incidence of failure to thrive and gastrointestinal symptoms were significantly higher in the ID group. Early diagnosis and proper treatment of ID are recommended. Especially in cases with risk factors such as failure to thrive or gastrointestinal manifestation, active evaluation of ID should be encouraged.
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Affiliation(s)
- Hye Eun Kwon
- Department of Pediatrics, Yonsei University College of Medicine, Seoul, Korea
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Carilla-Latorre S, Gallardo ME, Annesley SJ, Calvo-Garrido J, Graña O, Accari SL, Smith PK, Valencia A, Garesse R, Fisher PR, Escalante R. MidA is a putative methyltransferase that is required for mitochondrial complex I function. J Cell Sci 2010; 123:1674-83. [DOI: 10.1242/jcs.066076] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dictyostelium and human MidA are homologous proteins that belong to a family of proteins of unknown function called DUF185. Using yeast two-hybrid screening and pull-down experiments, we showed that both proteins interact with the mitochondrial complex I subunit NDUFS2. Consistent with this, Dictyostelium cells lacking MidA showed a specific defect in complex I activity, and knockdown of human MidA in HEK293T cells resulted in reduced levels of assembled complex I. These results indicate a role for MidA in complex I assembly or stability. A structural bioinformatics analysis suggested the presence of a methyltransferase domain; this was further supported by site-directed mutagenesis of specific residues from the putative catalytic site. Interestingly, this complex I deficiency in a Dictyostelium midA− mutant causes a complex phenotypic outcome, which includes phototaxis and thermotaxis defects. We found that these aspects of the phenotype are mediated by a chronic activation of AMPK, revealing a possible role of AMPK signaling in complex I cytopathology.
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Affiliation(s)
- Sergio Carilla-Latorre
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain
| | - M. Esther Gallardo
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain
- CIBERER, ISCIII, Madrid, Spain
| | - Sarah J. Annesley
- Department of Microbiology, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Javier Calvo-Garrido
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain
| | - Osvaldo Graña
- O. G., Bioinformatics Unit, Structural Biology and Biocomputing Program, A. V., Structural Computational Biology Group, Structural Biology and Biocomputing Program, Centro Nacional de Investigaciones Oncológicas, C/ Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Sandra L. Accari
- Department of Microbiology, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Paige K. Smith
- Department of Microbiology, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Alfonso Valencia
- O. G., Bioinformatics Unit, Structural Biology and Biocomputing Program, A. V., Structural Computational Biology Group, Structural Biology and Biocomputing Program, Centro Nacional de Investigaciones Oncológicas, C/ Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Rafael Garesse
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain
- CIBERER, ISCIII, Madrid, Spain
| | - Paul R. Fisher
- Department of Microbiology, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Ricardo Escalante
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain
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Mitochondrial translation and beyond: processes implicated in combined oxidative phosphorylation deficiencies. J Biomed Biotechnol 2010; 2010:737385. [PMID: 20396601 PMCID: PMC2854570 DOI: 10.1155/2010/737385] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Accepted: 01/29/2010] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial disorders are a heterogeneous group of often multisystemic and early fatal diseases, which are amongst the most common inherited human diseases. These disorders are caused by defects in the oxidative phosphorylation (OXPHOS) system, which comprises five multisubunit enzyme complexes encoded by both the nuclear and the mitochondrial genomes. Due to the multitude of proteins and intricacy of the processes required for a properly functioning OXPHOS system, identifying the genetic defect that underlies an OXPHOS deficiency is not an easy task, especially in the case of combined OXPHOS defects. In the present communication we give an extensive overview of the proteins and processes (in)directly involved in mitochondrial translation and the biogenesis of the OXPHOS system and their roles in combined OXPHOS deficiencies. This knowledge is important for further research into the genetic causes, with the ultimate goal to effectively prevent and cure these complex and often devastating disorders.
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Bénit P, El-Khoury R, Schiff M, Sainsard-Chanet A, Rustin P. Genetic background influences mitochondrial function: modeling mitochondrial disease for therapeutic development. Trends Mol Med 2010; 16:210-7. [PMID: 20382561 DOI: 10.1016/j.molmed.2010.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 03/11/2010] [Accepted: 03/15/2010] [Indexed: 12/21/2022]
Abstract
Genetic background strongly influences the phenotype of human mitochondrial diseases. Mitochondrial biogenesis and function require up to 1500 nuclear genes, providing myriad opportunities for effects on disease expression. Phenotypic variability, combined with relative rarity, constitutes a major obstacle to establish cohorts for clinical trials. Animal models are, therefore, potentially valuable. However, several of these show no or very mild disease phenotypes compared with patients and can not be used for therapeutic studies. One reason might be the insufficient attention paid to the need for genetic diversity in order to capture the effects of genetic background on disease expression. Here, we use data from various models to emphasize the need to preserve genetic diversity when studying mitochondrial disease phenotypes or drug effects.
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Jex AR, Hall RS, Littlewood DTJ, Gasser RB. An integrated pipeline for next-generation sequencing and annotation of mitochondrial genomes. Nucleic Acids Res 2009; 38:522-33. [PMID: 19892826 PMCID: PMC2811008 DOI: 10.1093/nar/gkp883] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial (mt) genomics represents an understudied but important field of molecular biology. Increasingly, mt dysfunction is being linked to a range of human diseases, including neurodegenerative disorders, diabetes and impairment of childhood development. In addition, mt genomes provide important markers for systematic, evolutionary and population genetic studies. Some technological limitations have prevented the expanded generation and utilization of mt genomic data for some groups of organisms. These obstacles most acutely impede, but are not limited to, studies requiring the determination of complete mt genomic data from minute amounts of material (e.g. biopsy samples or microscopic organisms). Furthermore, post-sequencing bioinformatic annotation and analyses of mt genomes are time consuming and inefficient. Herein, we describe a high-throughput sequencing and bioinformatic pipeline for mt genomics, which will have implications for the annotation and analysis of other organellar (e.g. plastid or apicoplast genomes) and virus genomes as well as long, contiguous regions in nuclear genomes. We utilize this pipeline to sequence and annotate the complete mt genomes of 12 species of parasitic nematode (order Strongylida) simultaneously, each from an individual organism. These mt genomic data provide a rich source of markers for studies of the systematics and population genetics of a group of socioeconomically important pathogens of humans and other animals.
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Affiliation(s)
- Aaron R Jex
- Department of Veterinary Science, The University of Melbourne, Victoria 3030, Australia.
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