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Wei LY, Chen XQ, Huang L, Shan QW, Tang Q. Liver transplantation for mitochondrial DNA depletion syndrome caused by MPV17 deficiency: a case report and literature review. Front Surg 2024; 11:1348806. [PMID: 39055132 PMCID: PMC11269130 DOI: 10.3389/fsurg.2024.1348806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 06/24/2024] [Indexed: 07/27/2024] Open
Abstract
Objective To study the effectiveness of liver transplantation (LT) in treating mitochondrial DNA depletion syndrome (MDS) caused by the MPV17 gene variant. Case presentation A boy aged 2.8 years presented with edema of the lower limbs and abdomen, which persisted for over 10 days and was of unknown origin; this was accompanied by abnormal liver function, intractable hypoglycemia, and hyperlactatemia. During the second week of onset, he developed acute-on-chronic liver failure and was diagnosed with MDS due to homozygous variant c.293C>T in the MPV17 gene. Subsequently, he underwent LT from a cadaveric donor. At follow-up after 15 months, his liver function was found to be normal, without any symptoms. Additionally, a literature review was performed that included MDS patients with the MPV17 variant who underwent LT. The results demonstrated that the survival rates for MDS patients who underwent LT were 69.5%, 38.6%, 38.6%, and 38.6% at 1-year, 5-year, 10-year, and 20-year intervals, respectively. Sub-group analyses revealed the survival rate of MDS patients with isolated liver disease (83.33%, 5/6) was higher than that of hepatocerebral MDS patients (44.44%, 8/18). Fifteen variants were identified in the MPV17 gene, and patients with the c.293C>T (p.P98l) variant exhibited the highest survival rate. Conclusion Hepatocerebral MDS patients without neurological symptoms may benefit from LT.
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Affiliation(s)
- Liu-Yuan Wei
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
- Department of Pediatrics, The Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou Worker's Hospital, Liuzhou, China
| | - Xiu-Qi Chen
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Li Huang
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Qing-Wen Shan
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Qing Tang
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
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2
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Lopriore P, Palermo G, Meli A, Bellini G, Benevento E, Montano V, Siciliano G, Mancuso M, Ceravolo R. Mitochondrial Parkinsonism: A Practical Guide to Genes and Clinical Diagnosis. Mov Disord Clin Pract 2024. [PMID: 38943319 DOI: 10.1002/mdc3.14148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 04/19/2024] [Accepted: 06/01/2024] [Indexed: 07/01/2024] Open
Abstract
BACKGROUND Primary mitochondrial diseases (PMDs) are the most common inborn errors of energy metabolism, with a combined prevalence of 1 in 4300. They can result from mutations in either nuclear DNA (nDNA) or mitochondrial DNA (mtDNA). These disorders are multisystemic and mainly affect high energy-demanding tissues, such as muscle and the central nervous system (CNS). Among many clinical features of CNS involvement, parkinsonism is one of the most common movement disorders in PMDs. METHODS This review provides a pragmatic educational overview of the most recent advances in the field of mitochondrial parkinsonism, from pathophysiology and genetic etiologies to phenotype and diagnosis. RESULTS mtDNA maintenance and mitochondrial dynamics alterations represent the principal mechanisms underlying mitochondrial parkinsonism. It can be present in isolation, alongside other movement disorders or, more commonly, as part of a multisystemic phenotype. Mutations in several nuclear-encoded genes (ie, POLG, TWNK, SPG7, and OPA1) and, more rarely, mtDNA mutations, are responsible for mitochondrial parkinsonism. Progressive external opthalmoplegia and optic atrophy may guide genetic etiology identification. CONCLUSION A comprehensive deep-phenotyping approach is needed to reach a diagnosis of mitochondrial parkinsonism, which lacks distinctive clinical features and exemplifies the intricate genotype-phenotype interplay of PMDs.
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Affiliation(s)
- Piervito Lopriore
- Unit of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Giovanni Palermo
- Unit of Neurology, Department of Clinical and Experimental Medicine, Center for Neurodegenerative Diseases-Parkinson's Disease and Movement Disorders, University of Pisa, Pisa, Italy
| | - Adriana Meli
- Unit of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Gabriele Bellini
- Unit of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
- Unit of Neurology, Department of Clinical and Experimental Medicine, Center for Neurodegenerative Diseases-Parkinson's Disease and Movement Disorders, University of Pisa, Pisa, Italy
| | - Elena Benevento
- Unit of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
- Unit of Neurology, Department of Clinical and Experimental Medicine, Center for Neurodegenerative Diseases-Parkinson's Disease and Movement Disorders, University of Pisa, Pisa, Italy
| | - Vincenzo Montano
- Unit of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Gabriele Siciliano
- Unit of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Michelangelo Mancuso
- Unit of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Roberto Ceravolo
- Unit of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
- Unit of Neurology, Department of Clinical and Experimental Medicine, Center for Neurodegenerative Diseases-Parkinson's Disease and Movement Disorders, University of Pisa, Pisa, Italy
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3
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Samanta A, Srivastava A, Mandal K, Sarma MS, Poddar U. MPV17 mutation-related mitochondrial DNA depletion syndrome: A case series in infants. Indian J Gastroenterol 2023; 42:569-574. [PMID: 36753038 DOI: 10.1007/s12664-022-01281-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/25/2022] [Indexed: 02/09/2023]
Abstract
MPV17 is a mitochondrial inner membrane protein, involved in transporting deoxynucleotides into the mitochondria. Pathogenic MPV17 mutations can cause mitochondrial deoxyribonucleic acid (DNA) depletion syndrome, which has a varied presentation with neurological, muscular and hepatic involvement. Presentation as liver failure is relatively uncommon. Here, we report four infants from four separate families with pathogenic, homozygous MPV17 mutations. All had predominant hepatic involvement with cholestasis, lactic acidosis and hypoketotic hypoglycemia. Three of them had presented with liver failure. Interestingly, one of them showed fluctuating liver functions, which worsened with infection and improved after aggressive treatment with antibiotics and supplements. Two of the four cases died in infancy, while the other two improved on conservative management with medium-chain triglyceride-based diet, vitamin supplements, co-enzyme Q and carnitine. The two surviving children are alive at 12 and 25 months of age with native liver with normal to mildly deranged liver function and no neurological dysfunction. Next-generation sequencing confirmed the diagnosis in all of our cases. One of the detected mutations, c.55delC (p.Gln19ArgfsTer3) is a novel pathogenic frameshift mutation, while another mutation c.388G>C (p.Ala130Pro), which was previously reported in Single Nucleotide Polymorphism Database in heterozygous form, is being predicted as likely pathogenic in our case series. We, therefore, propose mutation testing for MPV17 gene during evaluation of indeterminate infantile liver failure, especially those with hypoglycemia and raised plasma lactate.
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Affiliation(s)
- Arghya Samanta
- Department of Pediatric Gastroenterology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, 226 014, India
| | - Anshu Srivastava
- Department of Pediatric Gastroenterology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, 226 014, India.
| | - Kausik Mandal
- Department of Medical Genetics, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, 226 014, India
| | - Moinak Sen Sarma
- Department of Pediatric Gastroenterology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, 226 014, India
| | - Ujjal Poddar
- Department of Pediatric Gastroenterology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, 226 014, India
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4
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Huang AC, Ebel NH, Romero D, Martin B, Jhun I, Brown M, Enns GM, Esquivel C, Bonham C. Outcomes after liver transplantation in MPV17 deficiency (Navajo neurohepatopathy): A single-center case series. Pediatr Transplant 2022; 26:e14274. [PMID: 35466509 DOI: 10.1111/petr.14274] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 02/22/2022] [Accepted: 03/09/2022] [Indexed: 02/03/2023]
Abstract
BACKGROUND MPV17-related mitochondrial DNA maintenance defect (MPV17 deficiency) is a rare, autosomal recessive mitochondrial DNA depletion syndrome with a high mortality rate in infancy and early childhood due to progression to liver failure. Liver transplantation for children with MPV17 deficiency has been considered controversial due to uncertainty about the potential progression of extrahepatic manifestations following liver transplantation. METHODS We describe our institution's experience for two infants diagnosed with infantile MPV17 deficiency who presented in acute on chronic liver failure, but with normal development and normal neurological status who successfully underwent liver transplantation. RESULTS Both patients underwent successful liver transplantation with normal development and neurological status at 3 years and 16 months post-transplant, respectively. CONCLUSIONS In this rare disease population, we describe two infants with MPV17 deficiency who underwent liver transplantation for acute on chronic liver failure who continue to have normal development, without progression of neurological disease. MPV17 deficiency should not be considered a contraindication to liver transplantation.
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Affiliation(s)
- Alice C Huang
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Noelle H Ebel
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Lucile Packard Children's Hospital Stanford, Stanford University, Palo Alto, California, USA
| | - Danielle Romero
- Department of Pediatric Liver Transplant, Lucile Packard Children's Hospital Stanford, Stanford University, Palo Alto, California, USA
| | - Brock Martin
- Department of Pathology, Stanford University, Palo Alto, California, USA
| | - Iny Jhun
- Department of Pathology, Stanford University, Palo Alto, California, USA
| | - Megan Brown
- Department of Pediatric Liver Transplant, Lucile Packard Children's Hospital Stanford, Stanford University, Palo Alto, California, USA
| | - Gregory M Enns
- Division of Medical Genetics, Department of Pediatrics, Lucile Packard Children's Hospital Stanford, Stanford University, Palo Alto, California, USA
| | - Carlos Esquivel
- Division of Abdominal Transplantation, Department of Surgery, Stanford University, Palo Alto, California, USA
| | - Clark Bonham
- Division of Abdominal Transplantation, Department of Surgery, Stanford University, Palo Alto, California, USA
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5
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Gene Therapy for Mitochondrial Diseases: Current Status and Future Perspective. Pharmaceutics 2022; 14:pharmaceutics14061287. [PMID: 35745859 PMCID: PMC9231068 DOI: 10.3390/pharmaceutics14061287] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/09/2022] [Accepted: 06/15/2022] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial diseases (MDs) are a group of severe genetic disorders caused by mutations in the nuclear or mitochondrial genome encoding proteins involved in the oxidative phosphorylation (OXPHOS) system. MDs have a wide range of symptoms, ranging from organ-specific to multisystemic dysfunctions, with different clinical outcomes. The lack of natural history information, the limits of currently available preclinical models, and the wide range of phenotypic presentations seen in MD patients have all hampered the development of effective therapies. The growing number of pre-clinical and clinical trials over the last decade has shown that gene therapy is a viable precision medicine option for treating MD. However, several obstacles must be overcome, including vector design, targeted tissue tropism and efficient delivery, transgene expression, and immunotoxicity. This manuscript offers a comprehensive overview of the state of the art of gene therapy in MD, addressing the main challenges, the most feasible solutions, and the future perspectives of the field.
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6
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Manini A, Abati E, Comi GP, Corti S, Ronchi D. Mitochondrial DNA homeostasis impairment and dopaminergic dysfunction: A trembling balance. Ageing Res Rev 2022; 76:101578. [PMID: 35114397 DOI: 10.1016/j.arr.2022.101578] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/26/2021] [Accepted: 01/28/2022] [Indexed: 02/07/2023]
Abstract
Maintenance of mitochondrial DNA (mtDNA) homeostasis includes a variety of processes, such as mtDNA replication, repair, and nucleotides synthesis, aimed at preserving the structural and functional integrity of mtDNA molecules. Mutations in several nuclear genes (i.e., POLG, POLG2, TWNK, OPA1, DGUOK, MPV17, TYMP) impair mtDNA maintenance, leading to clinical syndromes characterized by mtDNA depletion and/or deletions in affected tissues. In the past decades, studies have demonstrated a progressive accumulation of multiple mtDNA deletions in dopaminergic neurons of the substantia nigra in elderly population and, to a greater extent, in Parkinson's disease patients. Moreover, parkinsonism has been frequently described as a prominent clinical feature in mtDNA instability syndromes. Among Parkinson's disease-related genes with a significant role in mitochondrial biology, PARK2 and LRRK2 specifically take part in mtDNA maintenance. Moreover, a variety of murine models (i.e., "Mutator", "MitoPark", "PD-mitoPstI", "Deletor", "Twinkle-dup" and "TwinkPark") provided in vivo evidence that mtDNA stability is required to preserve nigrostriatal integrity. Here, we review and discuss the clinical, genetic, and pathological background underlining the link between impaired mtDNA homeostasis and dopaminergic degeneration.
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7
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Saccharomyces cerevisiae as a Tool for Studying Mutations in Nuclear Genes Involved in Diseases Caused by Mitochondrial DNA Instability. Genes (Basel) 2021; 12:genes12121866. [PMID: 34946817 PMCID: PMC8701800 DOI: 10.3390/genes12121866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/20/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial DNA (mtDNA) maintenance is critical for oxidative phosphorylation (OXPHOS) since some subunits of the respiratory chain complexes are mitochondrially encoded. Pathological mutations in nuclear genes involved in the mtDNA metabolism may result in a quantitative decrease in mtDNA levels, referred to as mtDNA depletion, or in qualitative defects in mtDNA, especially in multiple deletions. Since, in the last decade, most of the novel mutations have been identified through whole-exome sequencing, it is crucial to confirm the pathogenicity by functional analysis in the appropriate model systems. Among these, the yeast Saccharomyces cerevisiae has proved to be a good model for studying mutations associated with mtDNA instability. This review focuses on the use of yeast for evaluating the pathogenicity of mutations in six genes, MPV17/SYM1, MRM2/MRM2, OPA1/MGM1, POLG/MIP1, RRM2B/RNR2, and SLC25A4/AAC2, all associated with mtDNA depletion or multiple deletions. We highlight the techniques used to construct a specific model and to measure the mtDNA instability as well as the main results obtained. We then report the contribution that yeast has given in understanding the pathogenic mechanisms of the mutant variants, in finding the genetic suppressors of the mitochondrial defects and in the discovery of molecules able to improve the mtDNA stability.
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8
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Bian WP, Pu SY, Xie SL, Wang C, Deng S, Strauss PR, Pei DS. Loss of mpv17 affected early embryonic development via mitochondria dysfunction in zebrafish. Cell Death Discov 2021; 7:250. [PMID: 34537814 PMCID: PMC8449779 DOI: 10.1038/s41420-021-00630-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/06/2021] [Accepted: 08/26/2021] [Indexed: 11/09/2022] Open
Abstract
MVP17 encodes a mitochondrial inner-membrane protein, and mutation of human MVP17 can cause mitochondria DNA depletion syndrome (MDDS). However, the underlying function of mpv17 is still elusive. Here, we developed a new mutant with mpv17 knockout by using the CRISPR/Cas9 system. The mpv17-/- zebrafish showed developmental defects in muscles, liver, and energy supply. The mpv17-/- larvae hardly survived beyond a month, and they showed abnormal growth during the development stage. Abnormal swimming ability was also found in the mpv17-/- zebrafish. The transmission electron microscope (TEM) observation indicated that the mpv17-/- zebrafish underwent severe mitochondria dysfunction and the disorder of mitochondrial cristae. As an energy producer, the defects of mitochondria significantly reduced ATP content in mpv17-/- zebrafish, compared to wild-type zebrafish. We hypothesized that the disorder of mitochondria cristae was contributed to the dysfunction of muscle and liver in the mpv17-/- zebrafish. Moreover, the content of major energy depot triglycerides (TAG) was decreased dramatically. Interestingly, after rescued with normal exogenous mitochondria by microinjection, the genes involved in the TAG metabolism pathway were recovered to a normal level. Taken together, this is the first report of developmental defects in muscles, liver, and energy supply via mitochondria dysfunction, and reveals the functional mechanism of mpv17 in zebrafish.
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Affiliation(s)
- Wan-Ping Bian
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, China
| | - Shi-Ya Pu
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, China.,School of Public Health and Management, Chongqing Medical University, 400016, Chongqing, China
| | - Shao-Lin Xie
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, China
| | - Chao Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, China
| | - Shun Deng
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, 400714, Chongqing, China
| | - Phyllis R Strauss
- Department of Biology, College of Science, Northeastern University, Boston, MA, 02115, USA
| | - De-Sheng Pei
- School of Public Health and Management, Chongqing Medical University, 400016, Chongqing, China.
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9
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Sperl LE, Hagn F. NMR Structural and Biophysical Analysis of the Disease-Linked Inner Mitochondrial Membrane Protein MPV17. J Mol Biol 2021; 433:167098. [PMID: 34116124 DOI: 10.1016/j.jmb.2021.167098] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/19/2021] [Accepted: 06/03/2021] [Indexed: 11/30/2022]
Abstract
MPV17 is an integral inner mitochondrial membrane protein, whose loss-of-function is linked to the hepatocerebral form of the mitochondrial-DNA-depletion syndrome, leading to a tissue-specific reduction of mitochondrial DNA and organ failure in infants. Several disease-causing mutations in MPV17 have been identified and earlier studies with reconstituted protein suggest that MPV17 forms a high conductivity channel in the membrane. However, the molecular and structural basis of the MPV17 functionality remain only poorly understood. In order to make MPV17 accessible to high-resolution structural studies, we here present an efficient protocol for its high-level production in E. coli and refolding into detergent micelles. Using biophysical and NMR methods, we show that refolded MPV17 in detergent micelles adopts a compact structure consisting of six membrane-embedded α-helices. Furthermore, we demonstrate that MPV17 forms oligomers in a lipid bilayer that are further stabilized by disulfide-bridges. In line with these findings, MPV17 could only be inserted into lipid nanodiscs of 8-12 nm in diameter if intrinsic cysteines were either removed by mutagenesis or blocked by chemical modification. Using this nanodisc reconstitution approach, we could show that disease-linked mutations in MPV17 abolish its oligomerization properties in the membrane. These data suggest that, induced by oxidative stress, MPV17 can alter its oligomeric state from a properly folded monomer to a disulfide-stabilized oligomeric pore which might be required for the transport of metabolic DNA precursors into the mitochondrial matrix to compensate for the damage caused by reactive oxygen species.
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Affiliation(s)
- Laura E Sperl
- Structural Membrane Biochemistry, Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany
| | - Franz Hagn
- Structural Membrane Biochemistry, Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany; Institute of Structural Biology, Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
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10
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Jacinto S, Guerreiro P, de Oliveira RM, Cunha-Oliveira T, Santos MJ, Grazina M, Rego AC, Outeiro TF. MPV17 Mutations Are Associated With a Quiescent Energetic Metabolic Profile. Front Cell Neurosci 2021; 15:641264. [PMID: 33815063 PMCID: PMC8011494 DOI: 10.3389/fncel.2021.641264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 02/08/2021] [Indexed: 02/03/2023] Open
Abstract
Mutations in the MPV17 gene are associated with hepatocerebral form of mitochondrial depletion syndrome. The mechanisms through which MPV17 mutations cause respiratory chain dysfunction and mtDNA depletion is still unclear. The MPV17 gene encodes an inner membrane mitochondrial protein that was recently described to function as a non-selective channel. Although its exact function is unknown, it is thought to be important in the maintenance of mitochondrial membrane potential (ΔΨm). To obtain more information about the role of MPV17 in human disease, we investigated the effect of MPV17 knockdown and of selected known MPV17 mutations associated with MPV17 disease in vitro. We used different approaches in order to evaluate the cellular consequences of MPV17 deficiency. We found that lower levels of MPV17 were associated with impaired mitochondrial respiration and with a quiescent energetic metabolic profile. All the mutations studied destabilized the protein, resulting in reduced protein levels. We also demonstrated that different mutations caused different cellular abnormalities, including increased ROS production, decreased oxygen consumption, loss of ΔΨm, and mislocalization of MPV17 protein. Our study provides novel insight into the molecular effects of MPV17 mutations and opens novel possibilities for testing therapeutic strategies for a devastating group of disorders.
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Affiliation(s)
- Sandra Jacinto
- Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Serviço de Neurologia Pediátrica, Hospital Dona Estefânia, Centro Hospitalar Universitário Lisboa Central-EPE, Lisboa, Portugal
| | - Patrícia Guerreiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Switch Laboratory, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, Katholiek Universiteit (KU), Leuven, Belgium
| | - Rita Machado de Oliveira
- CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | | | - Maria João Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Portugal
| | - Manuela Grazina
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Portugal
| | - Ana Cristina Rego
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.,Max Planck Institute for Experimental Medicine, Göttingen, Germany
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11
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Shimura M, Kuranobu N, Ogawa-Tominaga M, Akiyama N, Sugiyama Y, Ebihara T, Fushimi T, Ichimoto K, Matsunaga A, Tsuruoka T, Kishita Y, Umetsu S, Inui A, Fujisawa T, Tanikawa K, Ito R, Fukuda A, Murakami J, Kaji S, Kasahara M, Shiraki K, Ohtake A, Okazaki Y, Murayama K. Clinical and molecular basis of hepatocerebral mitochondrial DNA depletion syndrome in Japan: evaluation of outcomes after liver transplantation. Orphanet J Rare Dis 2020; 15:169. [PMID: 32703289 PMCID: PMC7379809 DOI: 10.1186/s13023-020-01441-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/15/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Hepatocerebral mitochondrial DNA depletion syndrome (MTDPS) is a disease caused by defects in mitochondrial DNA maintenance and leads to liver failure and neurological complications during infancy. Liver transplantation (LT) remains controversial due to poor outcomes associated with extrahepatic symptoms. The purposes of this study were to clarify the current clinical and molecular features of hepatocerebral MTDPS and to evaluate the outcomes of LT in MTDPS patients in Japan. RESULTS We retrospectively assessed the clinical and genetic findings, as well as the clinical courses, of 23 hepatocerebral MTDPS patients from a pool of 999 patients who were diagnosed with mitochondrial diseases between 2007 and 2019. Causative genes were identified in 18 of 23 patients: MPV17 (n = 13), DGUOK (n = 3), POLG (n = 1), and MICOS13 (n = 1). Eight MPV17-deficient patients harbored c.451dupC and all three DGUOK-deficient patients harbored c.143-307_170del335. The most common initial manifestation was failure to thrive (n = 13, 56.5%). The most frequent liver symptom was cholestasis (n = 21, 91.3%). LT was performed on 12 patients, including nine MPV17-deficient and two DGUOK-deficient patients. Among the 12 transplanted patients, five, including one with mild intellectual disability, survived; while seven who had remarkable neurological symptoms before LT died. Five of the MPV17-deficient survivors had either c.149G > A or c.293C > T. CONCLUSIONS MPV17 was the most common genetic cause of hepatocerebral MTDPS. The outcome of LT for MTDPS was not favorable, as previously reported, however, patients harboring MPV17 mutations associated with mild phenotypes such as c.149G > A or c.293C > T, and exhibiting no marked neurologic manifestations before LT, had a better prognosis after LT.
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Affiliation(s)
- Masaru Shimura
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Naomi Kuranobu
- Division of Pediatrics and Perinatology, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori, 683-8504, Japan
| | - Minako Ogawa-Tominaga
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Nana Akiyama
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Yohei Sugiyama
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Tomohiro Ebihara
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Takuya Fushimi
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Keiko Ichimoto
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Ayako Matsunaga
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Tomoko Tsuruoka
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Yoshihito Kishita
- Diagnostics and Therapeutic of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Hongo 2-1-1, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Shuichiro Umetsu
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama City Tobu Hospital, 3-6-1, Shimosueyoshi, Tsurumi-ku, Yokohama, Kanagawa, 230-0012, Japan
| | - Ayano Inui
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama City Tobu Hospital, 3-6-1, Shimosueyoshi, Tsurumi-ku, Yokohama, Kanagawa, 230-0012, Japan
| | - Tomoo Fujisawa
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama City Tobu Hospital, 3-6-1, Shimosueyoshi, Tsurumi-ku, Yokohama, Kanagawa, 230-0012, Japan
| | - Ken Tanikawa
- Department of Diagnostic Pathology, Yame General Hospital, 540-2, Takatsuka, Yame-shi, Fukuoka, 834-0034, Japan
| | - Reiko Ito
- Department of General Pediatrics and Interdisciplinary Medicine, National Center for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Akinari Fukuda
- Organ Transplantation Center, National Center for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Jun Murakami
- Division of Pediatrics and Perinatology, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori, 683-8504, Japan
| | - Shunsaku Kaji
- Department of Pediatrics, Tsuyama Chuo Hospital, Kawasaki 1756, Tsuyama-shi, Okayama, 708-0841, Japan
| | - Mureo Kasahara
- Organ Transplantation Center, National Center for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Kazuo Shiraki
- Division of Pediatrics and Perinatology, Tottori University Faculty of Medicine, 36-1 Nishi-cho, Yonago, Tottori, 683-8504, Japan
| | - Akira Ohtake
- Department of Pediatrics & Clinical Genomics, Faculty of Medicine, Saitama Medical University, 38 Morohongo, Moroyama, Saitama, 350-0495, Japan.,Center for Intractable Diseases, Saitama Medical University Hospital, 38 Morohongo, Moroyama, Saitama, 350-0495, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutic of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Hongo 2-1-1, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Kei Murayama
- Center for Medical Genetics, Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan.
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12
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Hu B, Yang M, Liao Z, Wei H, Zhao C, Li D, Hu S, Jiang X, Shi M, Luo Q, Zhang D, Nie Q, Zhang X, Li H. Mutation of TWNK Gene Is One of the Reasons of Runting and Stunting Syndrome Characterized by mtDNA Depletion in Sex-Linked Dwarf Chicken. Front Cell Dev Biol 2020; 8:581. [PMID: 32766243 PMCID: PMC7381202 DOI: 10.3389/fcell.2020.00581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/16/2020] [Indexed: 11/16/2022] Open
Abstract
Runting and stunting syndrome (RSS), which is characterized by low body weight, generally occurs early in life and leads to considerable economic losses in the commercial broiler industry. Our previous study has suggested that RSS is associated with mitochondria dysfunction in sex-linked dwarf (SLD) chickens. However, the molecular mechanism of RSS remains unknown. Based on the molecular diagnostics of mitochondrial diseases, we identified a recessive mutation c. 409G > A (p. Ala137Thr) of Twinkle mitochondrial DNA helicase (TWNK) gene and mitochondrial DNA (mtDNA) depletion in RSS chickens’ livers from strain N301. Bioinformatics investigations supported the pathogenicity of the TWNK mutation that is located on the extended peptide linker of Twinkle primase domain and might further lead to mtDNA depletion in chicken. Furthermore, overexpression of wild-type TWNK increases mtDNA copy number, whereas overexpression of TWNK A137T causes mtDNA depletion in vitro. Additionally, the TWNK c. 409G > A mutation showed significant associations with body weight, daily gain, pectoralis weight, crureus weight, and abdominal fat weight. Taken together, we corroborated that the recessive TWNK c. 409G > A (p. Ala137Thr) mutation is associated with RSS characterized by mtDNA depletion in SLD chicken.
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Affiliation(s)
- Bowen Hu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Minmin Yang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Zhiying Liao
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Haohui Wei
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Changbin Zhao
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Dajian Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Shuang Hu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | | | - Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
| | - Qingbin Luo
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Dexiang Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Qinghua Nie
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Xiquan Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Hongmei Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
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13
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Abstract
Neonatal acute liver failure (NALF) is a rare disease with a few known primary causes: gestational alloimmune liver disease (GALD), viral infections, metabolic diseases, and ischemic injury. Many cases still do not have a known cause. Laboratory evaluation may suggest a diagnosis. Most of the known causes have disease-specific treatments that improve outcomes. Survival is improving with better knowledge about and treatment options for GALD; however, overall mortality for NALF is still 24%. Liver transplant remains an important option for neonates with an indeterminate cause of NALF and those who do not respond to established treatments.
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Affiliation(s)
- Catherine Larson-Nath
- Pediatric Gastroenterology, Hepatology & Nutrition, University of Minnesota, 2450 Riverside Avenue, Minneapolis, MN 55454, USA
| | - Bernadette E Vitola
- Pediatric Gastroenterology, Hepatology & Nutrition, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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14
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Li H, Hu B, Luo Q, Hu S, Luo Y, Zhao B, Gan Y, Li Y, Shi M, Nie Q, Zhang D, Zhang X. Runting and Stunting Syndrome Is Associated With Mitochondrial Dysfunction in Sex-Linked Dwarf Chicken. Front Genet 2020; 10:1337. [PMID: 32010193 PMCID: PMC6978286 DOI: 10.3389/fgene.2019.01337] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 12/09/2019] [Indexed: 11/13/2022] Open
Abstract
Runting and stunting syndrome (RSS) in chicken are commonly known as “frozen chicken.” The disease is characterized by lower body weight and slow growth and the incidence rate is widely 5%–20% in sex-linked dwarf (SLD) chickens. However, the etiology of RSS in chickens has plagued researchers for several decades. In this study, histopathology studies demonstrated that the hepatocytes of the RSS chickens contain many mitochondria with damaged and outer and inner membrane along with vacuolar hydropic degeneration. No mtDNA mutation was detected, but our microarray data showed that RSS chickens exhibited abnormal expression of genes, many of which are involved in oxidative phosphorylation (OXPHOS) and fatty acid metabolism. In particular, nuclear gene IGF2BP3 was upregulated in RSS chickens' liver cells. The abnormal expression of these genes is likely to impair the OXPHOS, resulting in reduced ATP synthesis in the hepatocytes of the RSS chickens, which may in turn leads to poor weight gain and retarded growth or stunting of chicks. Our findings suggest that mitochondria dysfunction rather than chronic inflammation is responsible for the reduced growth and RSS in SLD chickens. Mutations in GHR have been shown to compromise mitochondrial function in SLD chickens. Since the mitochondrial damage in the RSS chicken is more severe, we suggest that extra genes are likely to be affected to exacerbate the phenotype.
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Affiliation(s)
- Hongmei Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Bowen Hu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Qingbin Luo
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Shuang Hu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yabiao Luo
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Bojing Zhao
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yanmin Gan
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Ying Li
- Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, College Park, MD, United States
| | - Qinghua Nie
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Dexiang Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Xiquan Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science, South China Agricultural University, Guangzhou, China
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15
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Hegarty R, Deheragoda M, Fitzpatrick E, Dhawan A. Paediatric fatty liver disease (PeFLD): All is not NAFLD - Pathophysiological insights and approach to management. J Hepatol 2018; 68:1286-1299. [PMID: 29471012 DOI: 10.1016/j.jhep.2018.02.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 02/11/2018] [Accepted: 02/13/2018] [Indexed: 12/14/2022]
Abstract
The recognition of a pattern of steatotic liver injury where histology mimicked alcoholic liver disease, but alcohol consumption was denied, led to the identification of non-alcoholic fatty liver disease (NAFLD). Non-alcoholic fatty liver disease has since become the most common chronic liver disease in adults owing to the global epidemic of obesity. However, in paediatrics, the term NAFLD seems incongruous: alcohol consumption is largely not a factor and inherited metabolic disorders can mimic or co-exist with a diagnosis of NAFLD. The term paediatric fatty liver disease may be more appropriate. In this article, we summarise the known causes of steatosis in children according to their typical, clinical presentation: i) acute liver failure; ii) neonatal or infantile jaundice; iii) hepatomegaly, splenomegaly or hepatosplenomegaly; iv) developmental delay/psychomotor retardation and perhaps most commonly; v) the asymptomatic child with incidental discovery of abnormal liver enzymes. We offer this model as a means to provide pathophysiological insights and an approach to management of the ever more complex subject of fatty liver.
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Affiliation(s)
- Robert Hegarty
- Paediatric Liver, GI and Nutrition Centre and Mowatlabs, King's College Hospital, London, United Kingdom
| | - Maesha Deheragoda
- Liver Histopathology, Institute of Liver Studies, King's College Hospital, London, United Kingdom
| | - Emer Fitzpatrick
- Paediatric Liver, GI and Nutrition Centre and Mowatlabs, King's College Hospital, London, United Kingdom
| | - Anil Dhawan
- Paediatric Liver, GI and Nutrition Centre and Mowatlabs, King's College Hospital, London, United Kingdom.
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16
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El-Hattab AW, Wang J, Dai H, Almannai M, Staufner C, Alfadhel M, Gambello MJ, Prasun P, Raza S, Lyons HJ, Afqi M, Saleh MAM, Faqeih EA, Alzaidan HI, Alshenqiti A, Flore LA, Hertecant J, Sacharow S, Barbouth DS, Murayama K, Shah AA, Lin HC, Wong LJC. MPV17-related mitochondrial DNA maintenance defect: New cases and review of clinical, biochemical, and molecular aspects. Hum Mutat 2018; 39:461-470. [PMID: 29282788 DOI: 10.1002/humu.23387] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/04/2017] [Accepted: 12/15/2017] [Indexed: 02/02/2023]
Abstract
Mitochondrial DNA (mtDNA) maintenance defects are a group of diseases caused by deficiency of proteins involved in mtDNA synthesis, mitochondrial nucleotide supply, or mitochondrial dynamics. One of the mtDNA maintenance proteins is MPV17, which is a mitochondrial inner membrane protein involved in importing deoxynucleotides into the mitochondria. In 2006, pathogenic variants in MPV17 were first reported to cause infantile-onset hepatocerebral mtDNA depletion syndrome and Navajo neurohepatopathy. To date, 75 individuals with MPV17-related mtDNA maintenance defect have been reported with 39 different MPV17 pathogenic variants. In this report, we present an additional 25 affected individuals with nine novel MPV17 pathogenic variants. We summarize the clinical features of all 100 affected individuals and review the total 48 MPV17 pathogenic variants. The vast majority of affected individuals presented with an early-onset encephalohepatopathic disease characterized by hepatic and neurological manifestations, failure to thrive, lactic acidemia, and mtDNA depletion detected mainly in liver tissue. Rarely, MPV17 deficiency can cause a late-onset neuromyopathic disease characterized by myopathy and peripheral neuropathy with no or minimal liver involvement. Approximately half of the MPV17 pathogenic variants are missense. A genotype with biallelic missense variants, in particular homozygous p.R50Q, p.P98L, and p.R41Q, can carry a relatively better prognosis.
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Affiliation(s)
- Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatric Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Julia Wang
- Medical Scientist Training Program and Program in Developmental Biology, Baylor College of Medicine, Houston, Texas
| | - Hongzheng Dai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Mohammed Almannai
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Christian Staufner
- Division of Neuropediatrics and Metabolic Medicine, Department of General Pediatrics, University Hospital Heidelberg, Heidelberg, Germany
| | - Majid Alfadhel
- King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Sciences, Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Michael J Gambello
- Division of Medical Genetics, Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Pankaj Prasun
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Saleem Raza
- Department of Pediatrics, St John Hospital and Medical Center and Wayne State University School of Medicine, Detroit, Michigan
| | - Hernando J Lyons
- Department of Pediatrics, St John Hospital and Medical Center and Wayne State University School of Medicine, Detroit, Michigan
| | - Manal Afqi
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Mohammed A M Saleh
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Eissa A Faqeih
- Section of Medical Genetics, King Fahad Medical City, Children's Specialist Hospital, Riyadh, Saudi Arabia
| | - Hamad I Alzaidan
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Abduljabbar Alshenqiti
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Leigh Anne Flore
- Division of Genetic, Genomic, and Metabolic Disorders, Children's Hospital of Michigan and Wayne State University, Detroit, Michigan
| | - Jozef Hertecant
- Division of Clinical Genetics and Metabolic Disorders, Pediatric Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Stephanie Sacharow
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts
| | - Deborah S Barbouth
- Division of Clinical and Translational Genetics, Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miller School of Medicine, Miami, Florida
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Amit A Shah
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Henry C Lin
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
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17
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Paesano L, Perotti A, Buschini A, Carubbi C, Marmiroli M, Maestri E, Iannotta S, Marmiroli N. Markers for toxicity to HepG2 exposed to cadmium sulphide quantum dots; damage to mitochondria. Toxicology 2016; 374:18-28. [DOI: 10.1016/j.tox.2016.11.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/14/2016] [Accepted: 11/16/2016] [Indexed: 01/19/2023]
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18
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Deep Sequencing Reveals Novel Genetic Variants in Children with Acute Liver Failure and Tissue Evidence of Impaired Energy Metabolism. PLoS One 2016; 11:e0156738. [PMID: 27483465 PMCID: PMC4970743 DOI: 10.1371/journal.pone.0156738] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 05/10/2016] [Indexed: 01/21/2023] Open
Abstract
Background & Aims The etiology of acute liver failure (ALF) remains elusive in almost half of affected children. We hypothesized that inherited mitochondrial and fatty acid oxidation disorders were occult etiological factors in patients with idiopathic ALF and impaired energy metabolism. Methods Twelve patients with elevated blood molar lactate/pyruvate ratio and indeterminate etiology were selected from a retrospective cohort of 74 subjects with ALF because their fixed and frozen liver samples were available for histological, ultrastructural, molecular and biochemical analysis. Results A customized next-generation sequencing panel for 26 genes associated with mitochondrial and fatty acid oxidation defects revealed mutations and sequence variants in five subjects. Variants involved the genes ACAD9, POLG, POLG2, DGUOK, and RRM2B; the latter not previously reported in subjects with ALF. The explanted livers of the patients with heterozygous, truncating insertion mutations in RRM2B showed patchy micro- and macrovesicular steatosis, decreased mitochondrial DNA (mtDNA) content <30% of controls, and reduced respiratory chain complex activity; both patients had good post-transplant outcome. One infant with severe lactic acidosis was found to carry two heterozygous variants in ACAD9, which was associated with isolated complex I deficiency and diffuse hypergranular hepatocytes. The two subjects with heterozygous variants of unknown clinical significance in POLG and DGUOK developed ALF following drug exposure. Their hepatocytes displayed abnormal mitochondria by electron microscopy. Conclusion Targeted next generation sequencing and correlation with histological, ultrastructural and functional studies on liver tissue in children with elevated lactate/pyruvate ratio expand the spectrum of genes associated with pediatric ALF.
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19
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Evidence supporting the conceptual framework of cancer chemoprevention in canines. Sci Rep 2016; 6:26500. [PMID: 27216246 PMCID: PMC4877707 DOI: 10.1038/srep26500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 05/05/2016] [Indexed: 11/08/2022] Open
Abstract
As with human beings, dogs suffer from the consequences of cancer. We investigated the potential of a formulation comprised of resveratrol, ellagic acid, genistein, curcumin and quercetin to modulate biomarkers indicative of disease prevention. Dog biscuits were evaluated for palatability and ability to deliver the chemopreventive agents. The extent of endogenous DNA damage in peripheral blood lymphocytes from dogs given the dietary supplement or placebo showed no change. However, H2O2-inducible DNA damage was significantly decreased after consumption of the supplement. The expression of 11 of 84 genes related to oxidative stress was altered. Hematological parameters remained in the reference range. The concept of chemoprevention for the explicit benefit of the canine is compelling since dogs are an important part of our culture. Our results establish a proof-of-principle and provide a framework for improving the health and well-being of “man’s best friend”.
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20
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Leslie N, Wang X, Peng Y, Valencia CA, Khuchua Z, Hata J, Witte D, Huang T, Bove KE. Neonatal multiorgan failure due to ACAD9 mutation and complex I deficiency with mitochondrial hyperplasia in liver, cardiac myocytes, skeletal muscle, and renal tubules. Hum Pathol 2016; 49:27-32. [DOI: 10.1016/j.humpath.2015.09.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/21/2015] [Accepted: 09/25/2015] [Indexed: 11/16/2022]
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21
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Hänninen RL, Ahonen S, Màrquez M, Myöhänen MJ, Hytönen MK, Lohi H. Canine MPV17 truncation without clinical manifestations. Biol Open 2015; 4:1253-8. [PMID: 26353863 PMCID: PMC4610228 DOI: 10.1242/bio.013870] [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] [Indexed: 11/20/2022] Open
Abstract
Mitochondrial DNA depletion syndromes (MDS) are often serious autosomal recessively inherited disorders characterized by tissue-specific mtDNA copy number reduction. Many genes, including MPV17, are associated with the hepatocerebral form of MDS. MPV17 encodes for a mitochondrial inner membrane protein with a poorly characterized function. Several MPV17 mutations have been reported in association with a heterogeneous group of early-onset manifestations, including liver disease and neurological problems. Mpv17-deficient mice present renal and hearing defects. We describe here a MPV17 truncation mutation in dogs. We found a 1-bp insertion in exon 4 of the MPV17 gene, resulting in a frameshift and early truncation of the encoded protein. The mutation halves MPV17 expression in the lymphocytes of the homozygous dogs and the truncated protein is not translated in transfected cells. The insertion mutation is recurrent and exists in many unrelated breeds, although is highly enriched in the Boxer breed. Unexpectedly, despite the truncation of MPV17, we could not find any common phenotypes in the genetically affected dogs. The lack of observable phenotype could be due to a late onset, mild symptoms or potential tissue-specific compensatory mechanisms. This study suggests species-specific differences in the manifestation of the MPV17 defects and establishes a novel large animal model to further study MPV17 function and role in mitochondrial biology.
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Affiliation(s)
- Reetta L Hänninen
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki and Folkhälsan Research Center, Helsinki 00014, Finland
| | - Saija Ahonen
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki and Folkhälsan Research Center, Helsinki 00014, Finland
| | - Merce Màrquez
- Banc de Teixits Animals de Catalunya (BTAC), Department Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Barcelona 08193, Spain
| | - Maarit J Myöhänen
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki 00014, Finland
| | - Marjo K Hytönen
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki and Folkhälsan Research Center, Helsinki 00014, Finland
| | - Hannes Lohi
- Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki and Folkhälsan Research Center, Helsinki 00014, Finland
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Löllgen S, Weiher H. The role of the Mpv17 protein mutations of which cause mitochondrial DNA depletion syndrome (MDDS): lessons from homologs in different species. Biol Chem 2015; 396:13-25. [PMID: 25205723 DOI: 10.1515/hsz-2014-0198] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 06/27/2014] [Indexed: 01/30/2023]
Abstract
Mitochondrial DNA depletion syndromes (MDDS) are severe pediatric diseases with diverse clinical manifestations. Gene mutations that underlie MDDS have been associated with alterations in the mitochondrial DNA (mtDNA) replication machinery or in mitochondrial deoxyribonucleoside triphosphate pools. However, the nuclear gene MPV17, whose mutated forms are associated with hepatocerebral MDDS in humans, plays a so-far unknown role in mtDNA maintenance. A high degree of conservation has been determined between MPV17 and its mouse (Mpv17), zebrafish (tra) and yeast (SYM1) homologs, respectively, whereby mutants in these cause very different phenotypes. While dysfunction in this gene in humans causes fatal liver disease, kidney pathology is induced in mice. Moreover, in zebrafish inactivation of the Mpv17 homolog was detected as a viable dyscolouration mutant. Knock out of the yeast ortholog results in a temperature-sensitive metabolic growth phenotype. Detailed analyses on common denominators between these different phenotypes strengthen the hypothesis that the Mpv17 protein forms a channel in the inner mitochondrial membrane, allowing small molecules - in vertebrates probably nucleotides, and in yeast probably intermediates of the tricarboxylic acid cycle - to pass. Moreover, a function modifying the pathologic manifestations of MPV17-related disease in mice has been identified. This signaling pathway remarkably involves the non-mitochondrial catalytic subunit of DNA-dependent protein kinase (PRKDC), important in double-strand break repair resistance against reactive oxygen-induced genotoxic stress.
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Individual exome analysis in diagnosis and management of paediatric liver failure of indeterminate aetiology. J Hepatol 2014; 61:1056-63. [PMID: 25016221 PMCID: PMC4203706 DOI: 10.1016/j.jhep.2014.06.038] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/20/2014] [Accepted: 06/30/2014] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS In children with liver failure, as many as half remain of indeterminate aetiology. This hinders timely consideration of optimal treatment options. We posit that a significant subset of these children harbour known inherited metabolic liver diseases with atypical presentation or novel inborn errors of metabolism. We investigated the utility of whole-exome sequencing in three children with advanced liver disease of indeterminate aetiology. METHODS Patient 1 was a 10 year-old female diagnosed with Wilson disease but no detectable ATP7B mutations, and decompensated liver cirrhosis who underwent liver transplant and subsequently developed onset of neurodegenerative disease. Patient 2 was a full-term 2 day-old male with fatal acute liver failure of indeterminate aetiology. Patient 3 was an 8 year-old female with progressive syndromic cholestasis of unknown aetiology since age 3 months. RESULTS Unbiased whole-exome sequencing of germline DNA revealed homozygous mutations in MPV17 and SERAC1 as the disease causing genes in patient 1 and 2, respectively. This is the first demonstration of SERAC1 loss-of-function associated fatal acute liver failure. Patient 1 expands the phenotypic spectrum of the MPV17-related hepatocerebral mitochondrial DNA depletion syndrome. Patient 3 was found to have syndromic cholestasis due to bi-allelic NOTCH2 mutations. CONCLUSIONS Our findings validate the application of whole-exome sequencing in the diagnosis and management of children with advanced liver disease of indeterminate aetiology, with the potential to enhance optimal selection of treatment options and adequate counselling of families. Moreover, whole-exome sequencing revealed a hitherto unrecognized phenotypic spectrum of inherited metabolic liver diseases.
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Harvengt J, Wanty C, De Paepe B, Sempoux C, Revencu N, Smet J, Van Coster R, Lissens W, Seneca S, Weekers L, Sokal E, Debray FG. Clinical variability in neurohepatic syndrome due to combined mitochondrial DNA depletion and Gaucher disease. Mol Genet Metab Rep 2014; 1:223-231. [PMID: 27896091 PMCID: PMC5121303 DOI: 10.1016/j.ymgmr.2014.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 04/08/2014] [Indexed: 01/10/2023] Open
Abstract
A 1-year-old girl born to consanguineous parents presented with unexplained liver failure, leading to transplantation at 19 months. Subsequent partial splenectomy for persistent cytopenia showed the presence of foamy cells, and Gaucher disease was confirmed by homozygosity for the p.Leu483Pro mutation in the GBA gene. She was treated by enzyme replacement therapy (ERT). Clinical follow-up showed mild developmental delay, strabismus, nystagmus and oculomotor apraxia. Biochemical studies revealed multiple respiratory chain deficiencies and a mosaic pattern of deficient complex IV immunostaining in liver and fibroblast. Molecular analysis identified a mtDNA depletion syndrome due to the homozygous p.Pro98Leu mutation in MPV17. A younger sister unaffected by mtDNA depletion, presented with pancytopenia and hepatosplenomegaly. ERT for Gaucher disease resulted in visceral normalization without any neurological symptom. A third sister, affected by both conditions, had marked developmental delay, strabismus and ophthalmoplegia but no liver cirrhosis. In conclusion, intrafamilal variability occurs in MPV17-related disease. The combined pathological effect of Gaucher and mitochondrial diseases can negatively impact neurological and liver functions and influence the outcome in consanguineous families. The immunocytochemical staining of OXPHOS protein in tissues and cultured cells is a powerful tool revealing mosaic pattern of deficiency pointing to mtDNA-related mitochondrial disorders.
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Affiliation(s)
- Julie Harvengt
- Metabolic Unit, Department of Medical Genetics, CHU-CHC, Liège, Belgium
| | - Catherine Wanty
- Liver Unit, Department of Pediatrics, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Boel De Paepe
- Department of Pediatrics, Division of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Christine Sempoux
- Department of pathology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Nicole Revencu
- Department of Medical Genetics, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Joél Smet
- Department of Pediatrics, Division of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Rudy Van Coster
- Department of Pediatrics, Division of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Willy Lissens
- Department of Medical Genetics, University Hospital AZ-VUB, Brussels, Belgium
| | - Sara Seneca
- Department of Medical Genetics, University Hospital AZ-VUB, Brussels, Belgium
| | - Laurent Weekers
- Metabolic Unit, Department of Medical Genetics, CHU-CHC, Liège, Belgium
| | - Etienne Sokal
- Liver Unit, Department of Pediatrics, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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Nogueira C, Almeida LS, Nesti C, Pezzini I, Videira A, Vilarinho L, Santorelli FM. Syndromes associated with mitochondrial DNA depletion. Ital J Pediatr 2014; 40:34. [PMID: 24708634 PMCID: PMC3985578 DOI: 10.1186/1824-7288-40-34] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 03/28/2014] [Indexed: 01/21/2023] Open
Abstract
Mitochondrial dysfunction accounts for a large group of inherited metabolic disorders most of which are due to a dysfunctional mitochondrial respiratory chain (MRC) and, consequently, deficient energy production. MRC function depends on the coordinated expression of both nuclear (nDNA) and mitochondrial (mtDNA) genomes. Thus, mitochondrial diseases can be caused by genetic defects in either the mitochondrial or the nuclear genome, or in the cross-talk between the two. This impaired cross-talk gives rise to so-called nuclear-mitochondrial intergenomic communication disorders, which result in loss or instability of the mitochondrial genome and, in turn, impaired maintenance of qualitative and quantitative mtDNA integrity. In children, most MRC disorders are associated with nuclear gene defects rather than alterations in the mtDNA itself. The mitochondrial DNA depletion syndromes (MDSs) are a clinically heterogeneous group of disorders with an autosomal recessive pattern of transmission that have onset in infancy or early childhood and are characterized by a reduced number of copies of mtDNA in affected tissues and organs. The MDSs can be divided into least four clinical presentations: hepatocerebral, myopathic, encephalomyopathic and neurogastrointestinal. The focus of this review is to offer an overview of these syndromes, listing the clinical phenotypes, together with their relative frequency, mutational spectrum, and possible insights for improving diagnostic strategies.
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Affiliation(s)
| | | | | | | | | | - Laura Vilarinho
- National Institute of Health, Genetics Department, Research and Development Unit, Porto, Portugal.
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Menezes MJ, Riley LG, Christodoulou J. Mitochondrial respiratory chain disorders in childhood: Insights into diagnosis and management in the new era of genomic medicine. Biochim Biophys Acta Gen Subj 2014; 1840:1368-79. [DOI: 10.1016/j.bbagen.2013.12.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 12/10/2013] [Accepted: 12/18/2013] [Indexed: 12/26/2022]
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Al-Hussaini A, Faqeih E, El-Hattab AW, Alfadhel M, Asery A, Alsaleem B, Bakhsh E, Ali A, Alasmari A, Lone K, Nahari A, Eyaid W, Al Balwi M, Craig K, Butterworth A, He L, Taylor RW. Clinical and molecular characteristics of mitochondrial DNA depletion syndrome associated with neonatal cholestasis and liver failure. J Pediatr 2014; 164:553-9.e1-2. [PMID: 24321534 DOI: 10.1016/j.jpeds.2013.10.082] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/23/2013] [Accepted: 10/29/2013] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To determine the frequency of mitochondrial DNA depletion syndrome (MDS) in infants with cholestasis and liver failure and to further clarify the clinical, biochemical, radiologic, histopathologic, and molecular features associated with MDS due to deoxyguanosine kinase (DGUOK) and MPV17 gene mutations. STUDY DESIGN We studied 20 infants with suspected hepatocerebral MDS referred to our tertiary care center between 2007 and 2013. Genomic DNA was isolated from blood leukocytes, liver, and/or skeletal muscle samples by standard methods. Mitochondrial DNA copy number relative to nuclear DNA levels was determined in muscle and/or liver DNA using real-time quantitative polymerase chain reaction and compared with age-matched controls. Nuclear candidate genes, including polymerase γ, MPV17, and DGUOK were sequenced using standard analyses. RESULTS We identified pathogenic MPV17 and DGUOK mutations in 11 infants (6 females) representing 2.5% of the 450 cases of infantile cholestasis and 22% of the 50 cases of infantile liver failure referred to our center during the study period. All of the 11 patients manifested cholestasis that was followed by a rapidly progressive liver failure and death before 2 years of life. Mitochondrial DNA depletion was demonstrated in liver or muscle for 8 out of the 11 cases where tissue was available. Seven patients had mutations in the MPV17 gene (3 novel mutations), 4 patients had DGUOK mutations (of which 2 were novel mutations). CONCLUSION Mutations in the MPV17 and DGUOK genes are present in a significant percentage of infants with liver failure and are associated with poor prognosis.
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Affiliation(s)
- Abdulrahman Al-Hussaini
- Division of Pediatric Gastroenterology, The Children's Hospital, King Fahad Medical City, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
| | - Eissa Faqeih
- Division of Medical Genetics, The Children's Hospital, King Fahad Medical City, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Ayman W El-Hattab
- Division of Medical Genetics, The Children's Hospital, King Fahad Medical City, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Ali Asery
- Division of Pediatric Gastroenterology, The Children's Hospital, King Fahad Medical City, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Badr Alsaleem
- Division of Pediatric Gastroenterology, The Children's Hospital, King Fahad Medical City, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Eman Bakhsh
- Department of Radiology, King Saud bin Abdulaziz University for Health Sciences, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Ashraf Ali
- Department of Pathology, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Ali Alasmari
- Division of Medical Genetics, The Children's Hospital, King Fahad Medical City, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Khurram Lone
- Division of Pediatric Gastroenterology, The Children's Hospital, King Fahad Medical City, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Ahmed Nahari
- Division of Pediatric Gastroenterology, The Children's Hospital, King Fahad Medical City, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Wafaa Eyaid
- Division of Genetics, Department of Pediatrics, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Mohammed Al Balwi
- Department of Pathology, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Riyadh, Saudi Arabia; King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Kate Craig
- Newcastle Mitochondrial Highly Specialized Services Diagnostic Laboratory, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Anna Butterworth
- Newcastle Mitochondrial Highly Specialized Services Diagnostic Laboratory, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Langping He
- Newcastle Mitochondrial Highly Specialized Services Diagnostic Laboratory, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert W Taylor
- Newcastle Mitochondrial Highly Specialized Services Diagnostic Laboratory, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, United Kingdom
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Al Sarkhy A, Al-Sunaid A, Abdullah A, AlFadhel M, Eiyad W. A novel MPV17 gene mutation in a Saudi infant causing fatal progressive liver failure. Ann Saudi Med 2014; 34:175-8. [PMID: 24894789 PMCID: PMC6074855 DOI: 10.5144/0256-4947.2014.175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We describe in this report the clinical, biochemical, and molecular features of a Saudi infant with hepatocerebral MDS secondary to a novel homozygous mutation in the MPV17 gene. An automated sequencing of the nuclear MPV17 gene was performed. The coding region (7 exons) of the MPV17 gene was amplified using an M13-tagged intronic primer and screened by direct sequencing of the PCR-amplified products (GenBank Association Number NM_002437.4). The sequencing of the entire coding region and intron-exon boundaries of MPV17 gene revealed a single homozygous variant, -c.278A > C(p.Q93P), which predicts the substitution of a highly conserved amino acid. This particular sequence variant has not been previously reported as a single-nucleotide polymorphism (SNP) or pathogenic mutation. Diagnostic workup for neonatal liver disorders should include mutation screening for known genes. The new advances in molecular genetics can help clinicians establish the diagnosis in a timely fashion, which may prevent a child from undergoing invasive and expensive investigations.
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Affiliation(s)
- Ahmed Al Sarkhy
- Gastroenterology Division, Pediatric Medicine, King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - Areej Al-Sunaid
- Gastroenterology Division, Department of Pediatrics, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Ahmad Abdullah
- Gastroenterology Division, Department of Pediatrics, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Majid AlFadhel
- Gastroenterology Division, Department of Pediatrics, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Wafa Eiyad
- Genetic division, Department of Pediatrics, King Saud Bin AbdulAziz University for Health Sciences, King AbdulAziz Medical City, Riyadh, Saudi Arabia
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Bottani E, Giordano C, Civiletto G, Di Meo I, Auricchio A, Ciusani E, Marchet S, Lamperti C, d'Amati G, Viscomi C, Zeviani M. AAV-mediated liver-specific MPV17 expression restores mtDNA levels and prevents diet-induced liver failure. Mol Ther 2014; 22:10-7. [PMID: 24247928 PMCID: PMC3880585 DOI: 10.1038/mt.2013.230] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/21/2013] [Indexed: 12/23/2022] Open
Abstract
Mutations in human MPV17 cause a hepatocerebral form of mitochondrial DNA depletion syndrome (MDS) hallmarked by early-onset liver failure, leading to premature death. Liver transplantation and frequent feeding using slow-release carbohydrates are the only available therapies, although surviving patients eventually develop slowly progressive peripheral and central neuropathy. The physiological role of Mpv17, including its functional link to mitochondrial DNA (mtDNA) maintenance, is still unclear. We show here that Mpv17 is part of a high molecular weight complex of unknown composition, which is essential for mtDNA maintenance in critical tissues, i.e. liver, of a Mpv17 knockout mouse model. On a standard diet, Mpv17-/- mouse shows hardly any symptom of liver dysfunction, but a ketogenic diet (KD) leads these animals to liver cirrhosis and failure. However, when expression of human MPV17 is carried out by adeno-associated virus (AAV)-mediated gene replacement, the Mpv17 knockout mice are able to reconstitute the Mpv17-containing supramolecular complex, restore liver mtDNA copy number and oxidative phosphorylation (OXPHOS) proficiency, and prevent liver failure induced by the KD. These results open new therapeutic perspectives for the treatment of MPV17-related liver-specific MDS.
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Affiliation(s)
- Emanuela Bottani
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCS, Milan, Italy
| | - Carla Giordano
- Department of Radiological, Oncological, and Pathological Sciences, Sapienza University, Roma, Italy
| | - Gabriele Civiletto
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCS, Milan, Italy
| | - Ivano Di Meo
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCS, Milan, Italy
| | - Alberto Auricchio
- Department of Pediatrics, Division of Medical Genetics, Telethon Institute of Genetics and Medicine, “Federico II” University, Naples, Italy
| | - Emilio Ciusani
- Laboratory of Clinical Pathology and Medical Genetics, The Foundation “Carlo Besta” Institute of Neurology IRCCS, Milan, Italy
| | - Silvia Marchet
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCS, Milan, Italy
| | - Costanza Lamperti
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCS, Milan, Italy
| | - Giulia d'Amati
- Department of Radiological, Oncological, and Pathological Sciences, Sapienza University, Roma, Italy
| | - Carlo Viscomi
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCS, Milan, Italy
| | - Massimo Zeviani
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCS, Milan, Italy
- MRC-Mitochondrial Biology Unit, Cambridge, UK
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Iida R, Ueki M, Fujihara J, Takeshita H, Kimura-Kataoka K, Yasuda T. Three Nonsynonymous Single Nucleotide Polymorphisms in the RhitH Gene Cause Reduction of the Repression Activity That Leads to Upregulation of M-LPH, a Participant in Mitochondrial Function. Biores Open Access 2013; 2:440-7. [PMID: 24380054 PMCID: PMC3869441 DOI: 10.1089/biores.2013.0042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Human Mpv17-like protein (M-LPH) has been suggested to play a role in mitochondrial function. In this study, we identified a RhitH (human regulator of heat-induced transcription) binding site in intron 1 of the M-LPH gene. Tissue distribution analysis showed that M-LPH was specifically distributed in tissues with high mitochondrial metabolism. Functional and genetic analyses of nonsynonymous single nucleotide polymorphisms (SNPs) in the RhitH gene revealed that p.Cys461Ser, p.Thr465Ala, and p.Leu495Gln, corresponding to substitutions in the zinc fingers, cause reductions in the repression activity that lead to upregulation of M-LPH expression. The analyses also showed that the minor allele frequencies of these SNPs are extremely low in worldwide populations.
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Affiliation(s)
- Reiko Iida
- Division of Life Science, Faculty of Medical Sciences, University of Fukui , Fukui, Japan . ; Research and Education Program for Life Science, Faculty of Medical Sciences, University of Fukui , Fukui, Japan
| | - Misuzu Ueki
- Division of Medical Genetics & Biochemistry, Faculty of Medical Sciences, University of Fukui , Fukui, Japan
| | - Junko Fujihara
- Department of Legal Medicine, Center for Integrated Research in Science, Shimane University School of Medicine , Izumo, Japan
| | - Haruo Takeshita
- Department of Legal Medicine, Center for Integrated Research in Science, Shimane University School of Medicine , Izumo, Japan
| | - Kaori Kimura-Kataoka
- Department of Legal Medicine, Center for Integrated Research in Science, Shimane University School of Medicine , Izumo, Japan
| | - Toshihiro Yasuda
- Research and Education Program for Life Science, Faculty of Medical Sciences, University of Fukui , Fukui, Japan . ; Division of Medical Genetics & Biochemistry, Faculty of Medical Sciences, University of Fukui , Fukui, Japan
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Abstract
To highlight differences between early-onset and adult mitochondrial depletion syndromes (MDS) concerning etiology and genetic background, pathogenesis, phenotype, clinical presentation and their outcome. MDSs most frequently occur in neonates, infants, or juveniles and more rarely in adolescents or adults. Mutated genes phenotypically presenting with adult-onset MDS include POLG1, TK2, TyMP, RRM2B, or PEO1/twinkle. Adult MDS manifest similarly to early-onset MDS, as myopathy, encephalo-myopathy, hepato-cerebral syndrome, or with chronic progressive external ophthalmoplegia (CPEO), fatigue, or only minimal muscular manifestations. Diagnostic work-up or treatment is not at variance from early-onset cases. Histological examination of muscle may be normal but biochemical investigations may reveal multiple respiratory chain defects. The outcome appears to be more favorable in adult than in early-onset forms. Mitochondrial depletion syndromes is not only a condition of neonates, infants, or juveniles but rarely also occurs in adults, presenting with minimal manifestations or manifestations like in the early-onset forms. Outcome of adult-onset MDS appears more favorable than early-onset MDS.
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Hazard FK, Ficicioglu CH, Ganesh J, Ruchelli ED. Liver pathology in infantile mitochondrial DNA depletion syndrome. Pediatr Dev Pathol 2013; 16:415-24. [PMID: 24050659 DOI: 10.2350/12-07-1229-oa.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mitochondrial DNA (mtDNA) depletion syndrome is a relatively novel cause of hepatic dysfunction in the pediatric population. It is caused by mutations in either mtDNA or nuclear DNA (nDNA) that result in a quantitative reduction in mtDNA and, in turn, dysfunctional oxidative phosphorylation. In infants, it results in the hepatocerebral phenotype, characterized by hyperbilirubinemia, coagulopathy, lactic acidosis, hypoglycemia, lethargy, encephalopathy, developmental delay, and hypotonia. Three infants diagnosed with mtDNA depletion syndrome at The Children's Hospital of Philadelphia were identified, and their clinical presentation, disease course, and histologic and ultrastructural features of liver samples (pre- and postmortem) were characterized. While a different mutant gene was identified in each child, they all showed clinical evidence of metabolic dysfunction soon after birth and expired by 1 year of age. Steatosis, cholestasis, and cytoplasmic crowding by atypical mitochondria were consistent pathologic liver findings. Other findings included hepatocyte hypereosinophilia, fibrosis, and hemosiderosis. This analysis provides insight into the important clinical signs/symptoms and histopathologic and ultrastructural features of mtDNA depletion syndrome in infants and young children. Knowledge of these characteristics will facilitate early recognition and appropriate treatment of this rare disorder. Additionally, ultrastructural evaluation of liver samples by electron microscopy is an important diagnostic component of hepatic dysfunction caused by metabolic abnormalities. This type of analysis should be routinely employed in the setting of unexplained cholestasis, especially when accompanied by steatosis and hepatocyte hypereosinophilia.
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Affiliation(s)
- Florette K Hazard
- 1 Departments of Pathology and Pediatrics, Stanford University School of Medicine, Stanford, CA 94305 USA
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Helbling D, Buchaklian A, Wang J, Wong LJ, Dimmock D. Reduced mitochondrial DNA content and heterozygous nuclear gene mutations in patients with acute liver failure. J Pediatr Gastroenterol Nutr 2013; 57:438-43. [PMID: 23783014 PMCID: PMC4966813 DOI: 10.1097/mpg.0b013e31829ef4b4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVES Historically, mitochondrial disorders have been associated with predominantly multisystem or neurological symptoms. If present, hepatic complications were thought to be a late feature. Recently, mutations in at least 4 nuclear genes have been identified in infants presenting with rapidly progressive hepatic failure, which may be precipitated by infection or drugs. We aimed to determine whether hepatic mitochondrial DNA (mtDNA) depletion is associated with apparently isolated hepatic failure in individuals with acute liver failure (ALF) of known or unknown etiologies undergoing liver transplant (LT). In addition, we wished to establish whether there was an excess of mutations in gene known to cause hepatic mtDNA depletion. METHODS Using previously established methods, we demonstrated that end-stage liver disease from known causes did not lead to hepatic mtDNA depletion. RESULTS Using thresholds derived from receiver-operator curve analysis, 66% of cases with ALF had probable or definite mtDNA depletion, including 34% with definite mtDNA depletion. There was a small but significant increase in the proportion of patients undergoing LT for ALF with heterozygous mutations known to lead to mtDNA depletion and hepatic failure compared with controls (P = 0.001). CONCLUSIONS Liver disease severe enough to require LT does not cause secondary mtDNA depletion; however, the majority of patients undergoing LT for ALF had reduced mtDNA content, which fell within the range seen in patients with classic mtDNA depletion. A subset of patients with ALF has mutations in genes known to lead to mtDNA depletion and hepatic failure. Together, these results suggest defective mtDNA maintenance is associated with ALF.
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Affiliation(s)
- Daniel Helbling
- Division of Genetics, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Adam Buchaklian
- Division of Genetics, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Jing Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - David Dimmock
- Division of Genetics, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
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35
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Yang JS, Kim J, Park S, Jeon J, Shin YE, Kim S. Spatial and functional organization of mitochondrial protein network. Sci Rep 2013; 3:1403. [PMID: 23466738 PMCID: PMC3590558 DOI: 10.1038/srep01403] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 02/21/2013] [Indexed: 12/24/2022] Open
Abstract
Characterizing the spatial organization of the human mitochondrial proteome will enhance our understanding of mitochondrial functions at the molecular level and provide key insight into protein-disease associations. However, the sub-organellar location and possible association with mitochondrial diseases are not annotated for most mitochondrial proteins. Here, we characterized the functional and spatial organization of mitochondrial proteins by assessing their position in the Mitochondrial Protein Functional (MPF) network. Network position was assigned to the MPF network and facilitated the determination of sub-organellar location and functional organization of mitochondrial proteins. Moreover, network position successfully identified candidate disease genes of several mitochondrial disorders. Thus, our data support the use of network position as a novel method to explore the molecular function and pathogenesis of mitochondrial proteins.
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Affiliation(s)
- Jae-Seong Yang
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang, Gyeongbuk, Korea, 790-784
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Piekutowska-Abramczuk D, Pronicki M, Strawa K, Karkucińska-Więckowska A, Szymańska-Dębińska T, Fidziańska A, Więckowski M, Jurkiewicz D, Ciara E, Jankowska I, Sykut-Cegielska J, Krajewska-Walasek M, Płoski R, Pronicka E. Novel c.191C>G (p.Pro64Arg)MPV17mutation identified in two pairs of unrelated Polish siblings with mitochondrial hepatoencephalopathy. Clin Genet 2013; 85:573-7. [DOI: 10.1111/cge.12228] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 07/02/2013] [Accepted: 07/02/2013] [Indexed: 12/28/2022]
Affiliation(s)
| | - M. Pronicki
- Department of Pathology; The Children's Memorial Health Institute; Warsaw Poland
| | - K. Strawa
- Department of Medical Genetics; Medical University of Warsaw; Warsaw Poland
| | | | | | - A. Fidziańska
- Neuromuscular Unit, Mossakowski Research Medical Center; Polish Academy of Science; Warsaw Poland
| | - M.R. Więckowski
- Laboratory of Bioenergetics, Biomembranes and Metabolic Regulation, Department of Biochememistry; Nencki Institute of Experimental Biology; Warsaw Poland
| | | | | | | | - J. Sykut-Cegielska
- Department of Metabolic Diseases; The Children's Memorial Health Institute; Warsaw Poland
| | | | - R. Płoski
- Department of Medical Genetics; Medical University of Warsaw; Warsaw Poland
| | - E. Pronicka
- Department of Metabolic Diseases; The Children's Memorial Health Institute; Warsaw Poland
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Selim L, Mehaney D. Mitochondrial encephalopathy with lactic acidosis and stroke-like episodes in a Japanese child: Clinical, radiological and molecular genetic analysis. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2013. [DOI: 10.1016/j.ejmhg.2013.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Rahman S. Gastrointestinal and hepatic manifestations of mitochondrial disorders. J Inherit Metab Dis 2013; 36:659-73. [PMID: 23674168 DOI: 10.1007/s10545-013-9614-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/13/2013] [Accepted: 04/16/2013] [Indexed: 12/23/2022]
Abstract
Inherited defects of oxidative phosphorylation lead to heterogeneous, often multisystem, mitochondrial diseases. This review highlights those mitochondrial syndromes with prominent gastrointestinal and hepatic symptoms, categorised according to underlying disease mechanism. Mitochondrial encephalopathies with major gastrointestinal involvement include mitochondrial neurogastrointestinal encephalopathy and ethylmalonic encephalopathy, which are each associated with highly specific clinical and metabolic profiles. Mitochondrial hepatopathies are most frequently caused by defects of mitochondrial DNA maintenance and expression. Although mitochondrial disorders are notorious for extreme clinical, biochemical and genetic heterogeneity, there are some pathognomonic clinical and metabolic clues that suggest a specific diagnosis, and these are highlighted. An approach to diagnosis of these complex disorders is presented, together with a genetic classification, including mitochondrial DNA disorders and nuclear-encoded defects of mitochondrial DNA maintenance and translation, OXPHOS complex assembly and mitochondrial membrane lipids. Finally, supportive and experimental therapeutic options for these currently incurable diseases are reviewed, including liver transplantation, allogeneic haematopoietic stem cell transplantation and gene therapy.
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Affiliation(s)
- Shamima Rahman
- Mitochondrial Research Group, Clinical and Molecular Genetics Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
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Krauss J, Astrinidis P, Astrinides P, Frohnhöfer HG, Walderich B, Nüsslein-Volhard C. transparent, a gene affecting stripe formation in Zebrafish, encodes the mitochondrial protein Mpv17 that is required for iridophore survival. Biol Open 2013; 2:703-10. [PMID: 23862018 PMCID: PMC3711038 DOI: 10.1242/bio.20135132] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/07/2013] [Indexed: 11/20/2022] Open
Abstract
In the skin of adult zebrafish, three pigment cell types arrange into alternating horizontal stripes, melanophores in dark stripes, xanthophores in light interstripes and iridophores in both stripes and interstripes. The analysis of mutants and regeneration studies revealed that this pattern depends on interactions between melanophores and xanthophores; however, the role of iridophores in this process is less understood. We describe the adult viable and fertile mutant transparent (tra), which shows a loss or strong reduction of iridophores throughout larval and adult stages. In addition, in adults only the number of melanophores is strongly reduced, and stripes break up into spots. Stripes in the fins are normal. By cell transplantations we show that tra acts cell-autonomously in iridophores, whereas the reduction in melanophores in the body occurs secondarily as a consequence of iridophore loss. We conclude that differentiated iridophores are required for the accumulation and maintenance of melanophores during pigment pattern formation. The tra mutant phenotype is caused by a small deletion in mpv17, an ubiquituously expressed gene whose protein product, like its mammalian and yeast homologs, localizes to mitochondria. Iridophore death might be the result of mitochondrial dysfunction, consistent with the mitochondrial DNA depletion syndrome observed in mammalian mpv17 mutants. The specificity of the tra phenotype is most likely due to redundancy after gene multiplication, making this mutant a valuable model to understand the molecular function of Mpv17 in mitochondria.
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Affiliation(s)
- Jana Krauss
- Max-Planck-Institut für Entwicklungsbiologie , Spemannstrasse 35, 72076 Tübingen , Germany
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Clinical, biochemical, cellular and molecular characterization of mitochondrial DNA depletion syndrome due to novel mutations in the MPV17 gene. Eur J Hum Genet 2013; 22:184-91. [PMID: 23714749 PMCID: PMC3895632 DOI: 10.1038/ejhg.2013.112] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 04/15/2013] [Accepted: 04/17/2013] [Indexed: 11/29/2022] Open
Abstract
Mitochondrial DNA (mtDNA) depletion syndromes (MDS) are severe autosomal recessive disorders associated with decreased mtDNA copy number in clinically affected tissues. The hepatocerebral form (mtDNA depletion in liver and brain) has been associated with mutations in the POLG, PEO1 (Twinkle), DGUOK and MPV17 genes, the latter encoding a mitochondrial inner membrane protein of unknown function. The aims of this study were to clarify further the clinical, biochemical, cellular and molecular genetic features associated with MDS due to MPV17 gene mutations. We identified 12 pathogenic mutations in the MPV17 gene, of which 11 are novel, in 17 patients from 12 families. All patients manifested liver disease. Poor feeding, hypoglycaemia, raised serum lactate, hypotonia and faltering growth were common presenting features. mtDNA depletion in liver was demonstrated in all seven cases where liver tissue was available. Mosaic mtDNA depletion was found in primary fibroblasts by PicoGreen staining. These results confirm that MPV17 mutations are an important cause of hepatocerebral mtDNA depletion syndrome, and provide the first demonstration of mosaic mtDNA depletion in human MPV17 mutant fibroblast cultures. We found that a severe clinical phenotype was associated with profound tissue-specific mtDNA depletion in liver, and, in some cases, mosaic mtDNA depletion in fibroblasts.
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Abstract
INTRODUCTION In the last 10 years the field of mitochondrial genetics has widened, shifting the focus from rare sporadic, metabolic disease to the effects of mitochondrial DNA (mtDNA) variation in a growing spectrum of human disease. The aim of this review is to guide the reader through some key concepts regarding mitochondria before introducing both classic and emerging mitochondrial disorders. SOURCES OF DATA In this article, a review of the current mitochondrial genetics literature was conducted using PubMed (http://www.ncbi.nlm.nih.gov/pubmed/). In addition, this review makes use of a growing number of publically available databases including MITOMAP, a human mitochondrial genome database (www.mitomap.org), the Human DNA polymerase Gamma Mutation Database (http://tools.niehs.nih.gov/polg/) and PhyloTree.org (www.phylotree.org), a repository of global mtDNA variation. AREAS OF AGREEMENT The disruption in cellular energy, resulting from defects in mtDNA or defects in the nuclear-encoded genes responsible for mitochondrial maintenance, manifests in a growing number of human diseases. AREAS OF CONTROVERSY The exact mechanisms which govern the inheritance of mtDNA are hotly debated. GROWING POINTS Although still in the early stages, the development of in vitro genetic manipulation could see an end to the inheritance of the most severe mtDNA disease.
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Affiliation(s)
| | - Gavin Hudson
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
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El-Hattab AW, Scaglia F. Mitochondrial DNA depletion syndromes: review and updates of genetic basis, manifestations, and therapeutic options. Neurotherapeutics 2013; 10:186-98. [PMID: 23385875 PMCID: PMC3625391 DOI: 10.1007/s13311-013-0177-6] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mitochondrial DNA (mtDNA) depletion syndromes (MDS) are a genetically and clinically heterogeneous group of autosomal recessive disorders that are characterized by a severe reduction in mtDNA content leading to impaired energy production in affected tissues and organs. MDS are due to defects in mtDNA maintenance caused by mutations in nuclear genes that function in either mitochondrial nucleotide synthesis (TK2, SUCLA2, SUCLG1, RRM2B, DGUOK, and TYMP) or mtDNA replication (POLG and C10orf2). MDS are phenotypically heterogeneous and usually classified as myopathic, encephalomyopathic, hepatocerebral or neurogastrointestinal. Myopathic MDS, caused by mutations in TK2, usually present before the age of 2 years with hypotonia and muscle weakness. Encephalomyopathic MDS, caused by mutations in SUCLA2, SUCLG1, or RRM2B, typically present during infancy with hypotonia and pronounced neurological features. Hepatocerebral MDS, caused by mutations in DGUOK, MPV17, POLG, or C10orf2, commonly have an early-onset liver dysfunction and neurological involvement. Finally, TYMP mutations have been associated with mitochondrial neurogastrointestinal encephalopathy (MNGIE) disease that typically presents before the age of 20 years with progressive gastrointestinal dysmotility and peripheral neuropathy. Overall, MDS are severe disorders with poor prognosis in the majority of affected individuals. No efficacious therapy is available for any of these disorders. Affected individuals should have a comprehensive evaluation to assess the degree of involvement of different systems. Treatment is directed mainly toward providing symptomatic management. Nutritional modulation and cofactor supplementation may be beneficial. Liver transplantation remains controversial. Finally, stem cell transplantation in MNGIE disease shows promising results.
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Affiliation(s)
- Ayman W. El-Hattab
- />Division of Medical Genetics, Department of Pediatrics, The Children’s Hospital, King Fahad Medical City and Faculty of Medicine, King Saud bin Abdulaziz University for Health Science, Riyadh, Kingdom of Saudi Arabia
| | - Fernando Scaglia
- />Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS BCM225, Houston, TX 77030 USA
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Lee IC, Lee NC, Lu JJ, Su PH. Mitochondrial depletion causes neonatal-onset leigh syndrome, myopathy, and renal tubulopathy. J Child Neurol 2013; 28:404-8. [PMID: 23307888 DOI: 10.1177/0883073812469722] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The authors describe a newborn with postnatal myopathy who subsequently developed feeding difficulties, ophthalmoplegia, ptosis, encephalopathy, and seizures. She became ventilator dependent after sudden apnea. The myopathy was without ragged red fibers in the muscle biopsy. An electron transport chain study showed a markedly generalized low level of enzyme activity, particularly in complexes I, I + III, and IV. An initial electroencephalogram finding was normal; subsequent electroencephalograms showed suppression bursts. The mitochondrial copy number in skeletal muscle was 2% of normal.
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Affiliation(s)
- Inn-Chi Lee
- Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan.
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Garone C, Rubio JC, Calvo SE, Naini A, Tanji K, Dimauro S, Mootha VK, Hirano M. MPV17 Mutations Causing Adult-Onset Multisystemic Disorder With Multiple Mitochondrial DNA Deletions. ACTA ACUST UNITED AC 2013; 69:1648-51. [PMID: 22964873 DOI: 10.1001/archneurol.2012.405] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE To identify the cause of an adult-onset multisystemic disease with multiple deletions of mitochondrial DNA (mtDNA). DESIGN Case report. SETTING University hospitals. PATIENT A 65-year-old man with axonal sensorimotor peripheral neuropathy, ptosis, ophthalmoparesis, diabetes mellitus, exercise intolerance, steatohepatopathy, depression, parkinsonism, and gastrointestinal dysmotility. RESULTS Skeletal muscle biopsy revealed ragged-red and cytochrome- c oxidase-deficient fibers, and Southern blot analysis showed multiple mtDNA deletions. No deletions were detected in fibroblasts, and the results of quantitative polymerase chain reaction showed that the amount of mtDNA was normal in both muscle and fibroblasts. Exome sequencing using a mitochondrial library revealed compound heterozygous MPV17 mutations (p.LysMet88-89MetLeu and p.Leu143*), a novel cause of mtDNA multiple deletions. CONCLUSIONS In addition to causing juvenile-onset disorders with mtDNA depletion, MPV17 mutations can cause adult-onset multisystemic disease with multiple mtDNA deletions.
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Navarro-Sastre A, Tort F, Garcia-Villoria J, Pons MR, Nascimento A, Colomer J, Campistol J, Yoldi ME, López-Gallardo E, Montoya J, Unceta M, Martinez MJ, Briones P, Ribes A. Mitochondrial DNA depletion syndrome: new descriptions and the use of citrate synthase as a helpful tool to better characterise the patients. Mol Genet Metab 2012; 107:409-15. [PMID: 22980518 DOI: 10.1016/j.ymgme.2012.08.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 08/25/2012] [Indexed: 01/21/2023]
Abstract
Mitochondrial DNA depletion syndrome (MDS) is a clinically heterogeneous group of mitochondrial disorders characterised by a quantitative reduction of the mitochondrial DNA copy number. Three main clinical forms of MDS: myopathic, encephalomyopathic and hepatocerebral have been defined, although patients may present with other MDS associated clinical symptoms and signs that cover a wide spectrum of onset age and disease. We studied 52 paediatric individuals suspected to have MDS. These patients have been divided into three different groups, and the appropriate MDS genes have been screened according to their clinical and biochemical phenotypes. Mutational study of DGUOK, MPV17, SUCLA2, SUCLG1 and POLG allowed us to identify 3 novel mutations (c.1048G>A and c.1049G>T in SUCLA2 and c.531+4A>T in SUCLG1) and 7 already known mutations in 10 patients (8 families). Seventeen patients presented with mtDNA depletion in liver or muscle, but the cause of mtDNA depletion still remains unknown in 8 of them. When possible, we quantified mtDNA/nDNA and CS activity in the same tissue sample, providing an additional tool for the study of MDS. The ratio (mtDNA/nDNA)/CS has shed some light in the discrepant results between the mtDNA copy number and the enzymatic respiratory chain activities of some cases.
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Affiliation(s)
- Aleix Navarro-Sastre
- Division of Inborn Errors of Metabolism, Department of Biochemistry and Molecular Genetics, Hospital Clinic, Instituto de Investigación Biomédica Pi Sunyer, 08028 Barcelona, Spain
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The channel-forming Sym1 protein is transported by the TIM23 complex in a presequence-independent manner. Mol Cell Biol 2012; 32:5009-21. [PMID: 23045398 DOI: 10.1128/mcb.00843-12] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The majority of multispanning inner mitochondrial membrane proteins utilize internal targeting signals, which direct them to the carrier translocase (TIM22 complex), for their import. MPV17 and its Saccharomyces cerevisiae orthologue Sym1 are multispanning inner membrane proteins of unknown function with an amino-terminal presequence that suggests they may be targeted to the mitochondria. Mutations affecting MPV17 are associated with mitochondrial DNA depletion syndrome (MDDS). Reconstitution of purified Sym1 into planar lipid bilayers and electrophysiological measurements have demonstrated that Sym1 forms a membrane pore. To address the biogenesis of Sym1, which oligomerizes in the inner mitochondrial membrane, we studied its import and assembly pathway. Sym1 forms a transport intermediate at the translocase of the outer membrane (TOM) complex. Surprisingly, Sym1 was not transported into mitochondria by an amino-terminal signal, and in contrast to what has been observed in carrier proteins, Sym1 transport and assembly into the inner membrane were independent of small translocase of mitochondrial inner membrane (TIM) and TIM22 complexes. Instead, Sym1 required the presequence of translocase for its biogenesis. Our analyses have revealed a novel transport mechanism for a polytopic membrane protein in which internal signals direct the precursor into the inner membrane via the TIM23 complex, indicating a presequence-independent function of this translocase.
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Selim L, Mehaney D, Hassan F, Sabry R, Zeyada R, Hassan S, Eldin IG, Bertini E. Mitochondrial DNA depletion syndrome presenting with ataxia and external ophthalmoplegia: Case report. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2012. [DOI: 10.1016/j.ejmhg.2012.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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48
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Lee IC, El-Hattab AW, Wang J, Li FY, Weng SW, Craigen WJ, Wong LJC. SURF1-associated leigh syndrome: A case series and novel mutations. Hum Mutat 2012; 33:1192-200. [DOI: 10.1002/humu.22095] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Accepted: 03/15/2012] [Indexed: 11/11/2022]
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Blakely EL, Butterworth A, Hadden RD, Bodi I, He L, McFarland R, Taylor RW. MPV17 mutation causes neuropathy and leukoencephalopathy with multiple mtDNA deletions in muscle. Neuromuscul Disord 2012; 22:587-91. [PMID: 22508010 PMCID: PMC3387382 DOI: 10.1016/j.nmd.2012.03.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/15/2012] [Accepted: 03/20/2012] [Indexed: 11/18/2022]
Abstract
Disorders of mitochondrial DNA (mtDNA) maintenance are clinically and genetically heterogeneous, embracing recessive mtDNA depletion syndromes affecting children and adult-onset multiple mtDNA deletion disorders. Here we show that mutation of MPV17 – a gene implicated in severe, infantile hepatocerebral mtDNA depletion disorders characterised by a loss of mtDNA copies – can also cause clonally-expanded mtDNA deletion and focal cytochrome c oxidase (COX) deficiency in skeletal muscle associated with an adult presentation of neuropathy and leukoencephalopathy. The mpv17 protein is therefore intimately involved in both the mtDNA replication and repair processes and associated with both quantitative and qualitative mtDNA abnormalities.
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Affiliation(s)
- Emma L. Blakely
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Anna Butterworth
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert D.M. Hadden
- Department of Neurology, King’s College Hospital, Denmark Hill, London SE5 9RS, UK
| | - Istvan Bodi
- Clinical Neuropathology, Academic Neuroscience Building, King’s College Hospital, Denmark Hill, London SE5 9RS, UK
| | - Langping He
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert McFarland
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert W. Taylor
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Corresponding author. Tel.: +44 191 2223685; fax: +44 191 2824373.
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Missing mitochondrial Mpv17 gene function induces tissue-specific cell-death pathway in the degenerating inner ear. Cell Tissue Res 2012; 347:343-56. [PMID: 22322422 DOI: 10.1007/s00441-012-1326-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 01/11/2012] [Indexed: 12/11/2022]
Abstract
The Mpv17 gene encodes a mitochondrial inner-membrane protein that has been implicated in the metabolism of reactive oxygen species. The loss of function in Mpv17-/- mice leads to early sensorineural deafness associated with severe inner ear degeneration and late onset of kidney failure. The present study demonstrates that the onset of the degeneration of the cochlear neuroepithelia is related to the onset of auditory function and appears to be first restricted to the outer hair cells (OHC), which subsequently undergo rapid degeneration. At the age of 18 days, the OHC lateral membrane degenerates and extensive vacuolization of the cytoplasm is followed by lysis of the OHCs. Such degenerative processes have been seen for the first time in relation to auditory dysfunction. The structural degeneration pattern of the OHC appears to be similar to the described paraptotic processes (an alternative form of programmed cell death) discussed in the literature as a cause of cytoplasmic neurodegeneration. In contrast, the melanocyte-like intermediate cells that are of neural crest origin and that are located in the stria vascularis, undergo apoptosis, as documented ultrastructurally. A lack of Mpv17 protein function in mitochondria thus seems to initiate tissue-specific cell-death pathways resulting in the pathology seen during the degeneration process.
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