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Rezaei M, Dourandish Z, Kiani Mehr G, Ghorbani A, Fatehi F. Cavitating leukodystrophy in a case of mitochondrial complex III deficiency due to LYRM7 mutation. Acta Neurol Belg 2024; 124:1409-1410. [PMID: 38592654 DOI: 10.1007/s13760-024-02529-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 03/13/2024] [Indexed: 04/10/2024]
Affiliation(s)
- Mojtaba Rezaei
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Dourandish
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Gilda Kiani Mehr
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Askar Ghorbani
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Farzad Fatehi
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.
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2
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Čunátová K, Fernández-Vizarra E. Pathological variants in nuclear genes causing mitochondrial complex III deficiency: An update. J Inherit Metab Dis 2024. [PMID: 39053894 DOI: 10.1002/jimd.12751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/24/2024] [Accepted: 05/02/2024] [Indexed: 07/27/2024]
Abstract
Mitochondrial disorders are a group of clinically and biochemically heterogeneous genetic diseases within the group of inborn errors of metabolism. Primary mitochondrial diseases are mainly caused by defects in one or several components of the oxidative phosphorylation system (complexes I-V). Within these disorders, those associated with complex III deficiencies are the least common. However, thanks to a deeper knowledge about complex III biogenesis, improved clinical diagnosis and the implementation of next-generation sequencing techniques, the number of pathological variants identified in nuclear genes causing complex III deficiency has expanded significantly. This updated review summarizes the current knowledge concerning the genetic basis of complex III deficiency, and the main clinical features associated with these conditions.
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Affiliation(s)
- Kristýna Čunátová
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
| | - Erika Fernández-Vizarra
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine, Padova, Italy
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3
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Jacques M, Landen S, Romero JA, Hiam D, Schittenhelm RB, Hanchapola I, Shah AD, Voisin S, Eynon N. Methylome and proteome integration in human skeletal muscle uncover group and individual responses to high-intensity interval training. FASEB J 2023; 37:e23184. [PMID: 37698381 DOI: 10.1096/fj.202300840rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/17/2023] [Accepted: 08/24/2023] [Indexed: 09/13/2023]
Abstract
Exercise is a major beneficial contributor to muscle metabolism, and health benefits acquired by exercise are a result of molecular shifts occurring across multiple molecular layers (i.e., epigenome, transcriptome, and proteome). Identifying robust, across-molecular level targets associated with exercise response, at both group and individual levels, is paramount to develop health guidelines and targeted health interventions. Sixteen, apparently healthy, moderately trained (VO2 max = 51.0 ± 10.6 mL min-1 kg-1 ) males (age range = 18-45 years) from the Gene SMART (Skeletal Muscle Adaptive Responses to Training) study completed a longitudinal study composed of 12-week high-intensity interval training (HIIT) intervention. Vastus lateralis muscle biopsies were collected at baseline and after 4, 8, and 12 weeks of HIIT. DNA methylation (~850 CpG sites) and proteomic (~3000 proteins) analyses were conducted at all time points. Mixed models were applied to estimate group and individual changes, and methylome and proteome integration was conducted using a holistic multilevel approach with the mixOmics package. A total of 461 proteins significantly changed over time (at 4, 8, and 12 weeks), whilst methylome overall shifted with training only one differentially methylated position (DMP) was significant (adj.p-value < .05). K-means analysis revealed cumulative protein changes by clusters of proteins that presented similar changes over time. Individual responses to training were observed in 101 proteins. Seven proteins had large effect-sizes >0.5, among them are two novel exercise-related proteins, LYRM7 and EPN1. Integration analysis showed bidirectional relationships between the methylome and proteome. We showed a significant influence of HIIT on the epigenome and more so on the proteome in human muscle, and uncovered groups of proteins clustering according to similar patterns across the exercise intervention. Individual responses to exercise were observed in the proteome with novel mitochondrial and metabolic proteins consistently changed across individuals. Future work is required to elucidate the role of these proteins in response to exercise.
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Affiliation(s)
- Macsue Jacques
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Victoria, Australia
| | - Shanie Landen
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Victoria, Australia
| | - Javier Alvarez Romero
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Victoria, Australia
| | - Danielle Hiam
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Victoria, Australia
- Institute of Nutrition and Health Sciences, Deakin University, Melbourne, Victoria, Australia
| | - Ralf B Schittenhelm
- Monash Proteomics & Metabolomics Facility, Monash University, Melbourne, Victoria, Australia
| | - Iresha Hanchapola
- Monash Proteomics & Metabolomics Facility, Monash University, Melbourne, Victoria, Australia
| | - Anup D Shah
- Monash Proteomics & Metabolomics Facility, Monash University, Melbourne, Victoria, Australia
| | - Sarah Voisin
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Victoria, Australia
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nir Eynon
- Institute for Health and Sport (iHeS), Victoria University, Melbourne, Victoria, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Victoria, Australia
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4
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Tonduti D, Zambon AA, Ghezzi D, Lamantea E, Izzo R, Parazzini C, Baldoli C, van der Knaap MS, Fumagalli F. Expanding the Spectrum of NUBPL-Related Leukodystrophy. Neuropediatrics 2023; 54:161-166. [PMID: 36868263 DOI: 10.1055/s-0043-1764214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Mitochondrial leukodystrophies constitute a group of different conditions presenting with a wide range of clinical presentation but with some shared neuroradiological features. Genetic defects in NUBPL have been recognized as cause of a pediatric onset mitochondrial leukodystrophy characterized by onset at the end of the first year of life with motor delay or regression and cerebellar signs, followed by progressive spasticity. Early magnetic resonance imagings (MRIs) show white matter abnormalities with predominant involvement of frontoparietal regions and corpus callosum. A striking cerebellar involvement is usually observed. Later MRIs show spontaneous improvement of white matter abnormalities but worsening of the cerebellar involvement evolving to global atrophy and progressive involvement of brainstem. After the 7 cases initially described, 11 more subjects were reported. Some of them were similar to patients from the original series while few others broadened the phenotypic spectrum. We performed a literature review and report on a new patient who further expand the spectrum of NUBPL-related leukodystrophy. With our study we confirm that the association of cerebral white matter and cerebellar cortex abnormalities is a feature commonly observed in early stages of the disease but beside the original and so far prevalent presentation, there are also uncommon phenotypes: clinical onset can be earlier and more severe than previously thought and signs of extraneurological involvement can be observed. Brain white matter can be diffusely abnormal without anteroposterior gradient, can progressively worsen, and cystic degeneration can be present. Thalami can be involved. Basal ganglia can also become involved during disease evolution.
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Affiliation(s)
- Davide Tonduti
- Unit of Pediatric Neurology, C.O.A.L.A (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Milan, Italy.,Department of Biomedical and Clinical Sciences, L. Sacco University Hospital, Università degli Studi di Milano, Milan, Italy
| | - Alberto A Zambon
- Neuromuscular Repair Unit, Division of Neuroscience, Institute of Experimental Neurology (InSpe), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Daniele Ghezzi
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Eleonora Lamantea
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Rossella Izzo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Cecilia Parazzini
- Pediatric Radiology and Neuroradiology Unit, C.O.A.L.A (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Milan, Italy
| | - Cristina Baldoli
- Neuroradiology Unit and CERMAC, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Marjo S van der Knaap
- Department of Child Neurology, Emma Children's Hospital, Amsterdam Leukodystrophy Center, Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, Netherlands.,Amsterdam Neuroscience, Cellular & Molecular Mechanisms, Vrije Universiteit, Amsterdam, Netherlands.,Center for Neurogenomics and Cognitive Research, Integrative Neurophysiology, Vrije Universiteit, Amsterdam, Netherlands
| | - Francesca Fumagalli
- Units of Neurology and Neurophysiology, IRCCS San Raffaele Scientific Institute, Milan, Italy.,San Raffaele Telethon Institute for Gene Therapy (SR-Tiget) and Pediatric Immunohematology and Bone Marrow Transplantation Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy
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5
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Alfattal R, Alfarhan M, Algaith AM, Albash B, Elshafie RM, Alshammari A, Alahmad A, Dashti F, Alsafi R, Alsharhan H. LYRM7-associated mitochondrial complex III deficiency with non-cavitating leukoencephalopathy and stroke-like episodes. Am J Med Genet A 2023; 191:1401-1411. [PMID: 36757047 DOI: 10.1002/ajmg.a.63143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/10/2023]
Abstract
Defects of respiratory chain complex III (CIII) result in characteristic but rare mitochondrial disorders associated with distinct neuroradiological findings. The underlying molecular defects affecting mitochondrial CIII assembly factors are few and yet to be identified. LYRM7 assembly factor is required for proper CIII assembly where it acts as a chaperone for the Rieske iron-sulfur (UQCRFS1) protein in the mitochondrial matrix and stabilizing it. We present here the seventeenth individual with LYRM7-associated mitochondrial leukoencephalopathy harboring a previously reported rare pathogenic homozygous LYRM 7 variant, c.2T>C, (p.Met1?). Like previously reported individuals, our 5-year-old male proband presented with recurrent metabolic and lactic acidosis, encephalopathy, and fatigue. Further, he has additional, previously unreported features, including an acute stroke like episode with bilateral central blindness and optic neuropathy, recurrent hyperglycemia and hypertension associated with metabolic crisis. However, he has no signs of psychomotor regression. He has been stable clinically with residual left-sided reduced visual acuity and amblyopia, and no more metabolic crises for 2-year-period while on the mitochondrial cocktail. Although the reported brain MRI findings in other affected individuals are homogenous, it is slightly different in our index, revealing evidence of bilateral almost symmetric multifocal periventricular T2 hyperintensities with hyperintensities of the optic nerves, optic chiasm, and corona radiata but with no cavitation or cystic changes. This report describes new clinical and radiological findings of LYRM7-associated disease. The report also summarizes the clinical and molecular data of previously reported individuals describing the full phenotypic spectrum.
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Affiliation(s)
- Rita Alfattal
- Department of Pediatrics, Al-Amiri Hospital, Ministry of Health, Kuwait
| | - Maryam Alfarhan
- Department of Pediatrics, Health Sciences Centre, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | | | - Buthaina Albash
- Kuwait Medical Genetics Center, Ministry of Health, Sulaibikhat, Kuwait
| | - Reem M Elshafie
- Kuwait Medical Genetics Center, Ministry of Health, Sulaibikhat, Kuwait
| | - Asma Alshammari
- Kuwait Medical Genetics Center, Ministry of Health, Sulaibikhat, Kuwait
| | - Ahmad Alahmad
- Kuwait Medical Genetics Center, Ministry of Health, Sulaibikhat, Kuwait
| | - Fatima Dashti
- Department of Radiology, Ibn Sina Hospital, Ministry of Health, Safat, Kuwait
| | - Rasha Alsafi
- Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya, Kuwait
| | - Hind Alsharhan
- Department of Pediatrics, Health Sciences Centre, Faculty of Medicine, Kuwait University, Safat, Kuwait.,Kuwait Medical Genetics Center, Ministry of Health, Sulaibikhat, Kuwait.,Department of Pediatrics, Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait.,Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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6
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Banerjee R, Purhonen J, Kallijärvi J. The mitochondrial coenzyme Q junction and complex III: biochemistry and pathophysiology. FEBS J 2022; 289:6936-6958. [PMID: 34428349 DOI: 10.1111/febs.16164] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/13/2021] [Accepted: 08/23/2021] [Indexed: 01/13/2023]
Abstract
Coenzyme Q (CoQ, ubiquinone) is the electron-carrying lipid in the mitochondrial electron transport system (ETS). In mammals, it serves as the electron acceptor for nine mitochondrial inner membrane dehydrogenases. These include the NADH dehydrogenase (complex I, CI) and succinate dehydrogenase (complex II, CII) but also several others that are often omitted in the context of respiratory enzymes: dihydroorotate dehydrogenase, choline dehydrogenase, electron-transferring flavoprotein dehydrogenase, mitochondrial glycerol-3-phosphate dehydrogenase, proline dehydrogenases 1 and 2, and sulfide:quinone oxidoreductase. The metabolic pathways these enzymes are involved in range from amino acid and fatty acid oxidation to nucleotide biosynthesis, methylation, and hydrogen sulfide detoxification, among many others. The CoQ-linked metabolism depends on CoQ reoxidation by the mitochondrial complex III (cytochrome bc1 complex, CIII). However, the literature is surprisingly limited as for the role of the CoQ-linked metabolism in the pathogenesis of human diseases of oxidative phosphorylation (OXPHOS), in which the CoQ homeostasis is directly or indirectly affected. In this review, we give an introduction to CIII function, and an overview of the pathological consequences of CIII dysfunction in humans and mice and of the CoQ-dependent metabolic processes potentially affected in these pathological states. Finally, we discuss some experimental tools to dissect the various aspects of compromised CoQ oxidation.
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Affiliation(s)
- Rishi Banerjee
- Folkhälsan Research Center, Helsinki, Finland.,Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
| | - Janne Purhonen
- Folkhälsan Research Center, Helsinki, Finland.,Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
| | - Jukka Kallijärvi
- Folkhälsan Research Center, Helsinki, Finland.,Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Finland
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7
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Zanfardino P, Doccini S, Santorelli FM, Petruzzella V. Tackling Dysfunction of Mitochondrial Bioenergetics in the Brain. Int J Mol Sci 2021; 22:8325. [PMID: 34361091 PMCID: PMC8348117 DOI: 10.3390/ijms22158325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/15/2022] Open
Abstract
Oxidative phosphorylation (OxPhos) is the basic function of mitochondria, although the landscape of mitochondrial functions is continuously growing to include more aspects of cellular homeostasis. Thanks to the application of -omics technologies to the study of the OxPhos system, novel features emerge from the cataloging of novel proteins as mitochondrial thus adding details to the mitochondrial proteome and defining novel metabolic cellular interrelations, especially in the human brain. We focussed on the diversity of bioenergetics demand and different aspects of mitochondrial structure, functions, and dysfunction in the brain. Definition such as 'mitoexome', 'mitoproteome' and 'mitointeractome' have entered the field of 'mitochondrial medicine'. In this context, we reviewed several genetic defects that hamper the last step of aerobic metabolism, mostly involving the nervous tissue as one of the most prominent energy-dependent tissues and, as consequence, as a primary target of mitochondrial dysfunction. The dual genetic origin of the OxPhos complexes is one of the reasons for the complexity of the genotype-phenotype correlation when facing human diseases associated with mitochondrial defects. Such complexity clinically manifests with extremely heterogeneous symptoms, ranging from organ-specific to multisystemic dysfunction with different clinical courses. Finally, we briefly discuss the future directions of the multi-omics study of human brain disorders.
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Affiliation(s)
- Paola Zanfardino
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy;
| | - Stefano Doccini
- IRCCS Fondazione Stella Maris, Calambrone, 56128 Pisa, Italy;
| | | | - Vittoria Petruzzella
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy;
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8
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Heidari E, Rasoulinezhad M, Pak N, Reza Ashrafi M, Heidari M, Banwell B, Garshasbi M, Reza Tavasoli A. Defective complex III mitochondrial respiratory chain due to a novel variant in CYC1 gene masquerades acute demyelinating syndrome or Leber hereditary optic neuropathy. Mitochondrion 2021; 60:12-20. [PMID: 34252606 DOI: 10.1016/j.mito.2021.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/03/2021] [Accepted: 07/07/2021] [Indexed: 11/15/2022]
Abstract
Complex III (CIII) is the third out of five mitochondrial respiratory chain complexes residing at the mitochondrial inner membrane. The assembly of 10 subunits encoded by nuclear DNA and one by mitochondrial DNA result in the functional CIII which transfers electrons from ubiquinol to cytochrome c. Deficiencies of CIII are among the least investigated mitochondrial disorders and thus clinical spectrum of patients with mutations in CIII is not well defined. We report on a 10-year-old girl born to consanguineous Iranian parents presenting with recurrent visual loss episodes and optic nerve contrast enhancement in brain imaging reminiscent of an acquired demyelination syndrome (i.e. optic neuritis or multiple sclerosis), who was ultimately confirmed to have a novel homozygous missense variant of unknown significance, c.949C > T; p.(Arg317Trp) in the CYC1 gene, a nuclear DNA subunit of complex III of the mitochondrial chain. Sanger sequencing confirmed the segregation of this variant with disease in the family. The effect of this variant on the protein structure was shown in-silico. Our findings, not only expand the clinical spectrum due to defects in CYC1 gene but also highlight that mitochondrial respiratory chain disorders could be considered as a potential differential diagnosis in children who present with unusual patterns of acquired demyelination syndromes (ADS). In addition, our results support the hypothesis that mitochondrial disorders might have an overlapping presentation with ADS.
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Affiliation(s)
- Erfan Heidari
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Maryam Rasoulinezhad
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Neda Pak
- Pediatric Radiology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Reza Ashrafi
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Morteza Heidari
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Brenda Banwell
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran.
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9
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Organization of the Respiratory Supercomplexes in Cells with Defective Complex III: Structural Features and Metabolic Consequences. Life (Basel) 2021; 11:life11040351. [PMID: 33920624 PMCID: PMC8074069 DOI: 10.3390/life11040351] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 12/13/2022] Open
Abstract
The mitochondrial respiratory chain encompasses four oligomeric enzymatic complexes (complex I, II, III and IV) which, together with the redox carrier ubiquinone and cytochrome c, catalyze electron transport coupled to proton extrusion from the inner membrane. The protonmotive force is utilized by complex V for ATP synthesis in the process of oxidative phosphorylation. Respiratory complexes are known to coexist in the membrane as single functional entities and as supramolecular aggregates or supercomplexes (SCs). Understanding the assembly features of SCs has relevant biomedical implications because defects in a single protein can derange the overall SC organization and compromise the energetic function, causing severe mitochondrial disorders. Here we describe in detail the main types of SCs, all characterized by the presence of complex III. We show that the genetic alterations that hinder the assembly of Complex III, not just the activity, cause a rearrangement of the architecture of the SC that can help to preserve a minimal energetic function. Finally, the major metabolic disturbances associated with severe SCs perturbation due to defective complex III are discussed along with interventions that may circumvent these deficiencies.
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10
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Natarajan S, Ramaswamy G, Kannan L, Gunasekeran V, Kathirvelu G. Acute Devastating Multifocal Cavitating Leukoencephalopathy in a Six-Year-Old Girl due to Missense Mutation in LYRM7 Gene. Pediatr Neurol 2021; 117:44-46. [PMID: 33662890 DOI: 10.1016/j.pediatrneurol.2020.12.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 10/22/2022]
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11
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Blackout in the powerhouse: clinical phenotypes associated with defects in the assembly of OXPHOS complexes and the mitoribosome. Biochem J 2021; 477:4085-4132. [PMID: 33151299 PMCID: PMC7657662 DOI: 10.1042/bcj20190767] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria produce the bulk of the energy used by almost all eukaryotic cells through oxidative phosphorylation (OXPHOS) which occurs on the four complexes of the respiratory chain and the F1–F0 ATPase. Mitochondrial diseases are a heterogenous group of conditions affecting OXPHOS, either directly through mutation of genes encoding subunits of OXPHOS complexes, or indirectly through mutations in genes encoding proteins supporting this process. These include proteins that promote assembly of the OXPHOS complexes, the post-translational modification of subunits, insertion of cofactors or indeed subunit synthesis. The latter is important for all 13 of the proteins encoded by human mitochondrial DNA, which are synthesised on mitochondrial ribosomes. Together the five OXPHOS complexes and the mitochondrial ribosome are comprised of more than 160 subunits and many more proteins support their biogenesis. Mutations in both nuclear and mitochondrial genes encoding these proteins have been reported to cause mitochondrial disease, many leading to defective complex assembly with the severity of the assembly defect reflecting the severity of the disease. This review aims to act as an interface between the clinical and basic research underpinning our knowledge of OXPHOS complex and ribosome assembly, and the dysfunction of this process in mitochondrial disease.
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12
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Fernandez-Vizarra E, Zeviani M. Mitochondrial disorders of the OXPHOS system. FEBS Lett 2020; 595:1062-1106. [PMID: 33159691 DOI: 10.1002/1873-3468.13995] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/21/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022]
Abstract
Mitochondrial disorders are among the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase [also called complex V (cV)]. The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by cV to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namely the mitochondrial and nuclear DNA, to the coordinated assembly of components and cofactors building each individual complex and eventually the supercomplexes. The genetic cause underlying around half of the diagnosed mitochondrial disease cases is currently known. Many of these cases result from pathogenic variants in genes encoding structural subunits or additional factors directly involved in the assembly of the ETC complexes. Here, we review the historical and most recent findings concerning the clinical phenotypes and the molecular pathological mechanisms underlying this particular group of disorders.
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Affiliation(s)
- Erika Fernandez-Vizarra
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Massimo Zeviani
- Venetian Institute of Molecular Medicine, Padova, Italy.,Department of Neurosciences, University of Padova, Italy
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13
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Human Mitochondrial Pathologies of the Respiratory Chain and ATP Synthase: Contributions from Studies of Saccharomyces cerevisiae. Life (Basel) 2020; 10:life10110304. [PMID: 33238568 PMCID: PMC7700678 DOI: 10.3390/life10110304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/14/2022] Open
Abstract
The ease with which the unicellular yeast Saccharomyces cerevisiae can be manipulated genetically and biochemically has established this organism as a good model for the study of human mitochondrial diseases. The combined use of biochemical and molecular genetic tools has been instrumental in elucidating the functions of numerous yeast nuclear gene products with human homologs that affect a large number of metabolic and biological processes, including those housed in mitochondria. These include structural and catalytic subunits of enzymes and protein factors that impinge on the biogenesis of the respiratory chain. This article will review what is currently known about the genetics and clinical phenotypes of mitochondrial diseases of the respiratory chain and ATP synthase, with special emphasis on the contribution of information gained from pet mutants with mutations in nuclear genes that impair mitochondrial respiration. Our intent is to provide the yeast mitochondrial specialist with basic knowledge of human mitochondrial pathologies and the human specialist with information on how genes that directly and indirectly affect respiration were identified and characterized in yeast.
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14
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Cherian A, Divya KP, Jose J, Thomas B. Multifocal cavitating leukodystrophy-A distinct image in mitochondrial LYRM7 mutations. Mult Scler Relat Disord 2020; 47:102615. [PMID: 33189022 DOI: 10.1016/j.msard.2020.102615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 10/13/2020] [Accepted: 11/02/2020] [Indexed: 10/23/2022]
Abstract
An adult woman presented with insidious onset slowly progressive symmetric spasticity and mild upper extremity dysmetria, with sparing of bowel and bladder functions. She had a distinct magnetic resonance imaging (MRI) pattern of bilateral symmetrical T2 hyperintensity involving periventricular especially parieto-occipital and deep cerebral white matter with multifocal small cavitations which were posterior predominant, sparing subcortical U fibres. Magnetic resonance spectroscopy (MRS) showed lactate peak. Her clinical exome sequencing revealed a pathogenic homozygous start-loss variation in exon 1 encoding the mitochondrial LYR motif-containing protein 7 (LYRM7 gene) which is an integral part of complex III of the mitochondrial respiratory chain. Our case was unique in the indolent adult onset leukodystrophy like presentation making her wheel chair bound by the fourth decade, while most reported patients to date had an early childhood presentation as repeated episodes of subacute leukoencephalopathy with motor regression or death by first decade. Myriad phenotypic presentation of the LYRM7 gene mutations reported till date is highlighted.
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Affiliation(s)
- Ajith Cherian
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala 695011, India
| | - K P Divya
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala 695011, India.
| | - Jithu Jose
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala 695011, India
| | - Bejoy Thomas
- Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala 695011, India
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15
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Novel approach to quantify mitochondrial content and intrinsic bioenergetic efficiency across organs. Sci Rep 2020; 10:17599. [PMID: 33077793 PMCID: PMC7572412 DOI: 10.1038/s41598-020-74718-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/05/2020] [Indexed: 01/09/2023] Open
Abstract
Human disease pathophysiology commonly involves metabolic disruption at both the cellular and subcellular levels. Isolated mitochondria are a powerful model for separating global cellular changes from intrinsic mitochondrial alterations. However, common laboratory practices for isolating mitochondria (e.g., differential centrifugation) routinely results in organelle preparations with variable mitochondrial purity. To overcome this issue, we developed a mass spectrometry-based method that quantitatively evaluates sample-specific percent mitochondrial enrichment. Sample-specific mitochondrial enrichment was then used to correct various biochemical readouts of mitochondrial function to a ‘fixed’ amount of mitochondrial protein, thus allowing for intrinsic mitochondrial bioenergetics, relative to the underlying proteome, to be assessed across multiple mouse tissues (e.g., heart, brown adipose, kidney, liver). Our results support the use of mitochondrial-targeted nLC-MS/MS as a method to quantitate mitochondrial enrichment on a per-sample basis, allowing for unbiased comparison of functional parameters between populations of mitochondria isolated from metabolically distinct tissues. This method can easily be applied across multiple experimental settings in which intrinsic shifts in the mitochondrial network are suspected of driving a given physiological or pathophysiological outcome.
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16
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Zhang J, Liu M, Zhang Z, Zhou L, Kong W, Jiang Y, Wang J, Xiao J, Wu Y. Genotypic Spectrum and Natural History of Cavitating Leukoencephalopathies in Childhood. Pediatr Neurol 2019; 94:38-47. [PMID: 30770271 DOI: 10.1016/j.pediatrneurol.2019.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 12/26/2018] [Accepted: 01/01/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND We aimed to delineate the pattern of natural course, neuroimaging features, and the genotypic spectrum of cavitating leukoencephalopathies. METHODS Children (age of onset ≤16 years) who met the criteria for cavitating leukoencephalopathies from January 2009 to October 2018 were identified. Whole-exome sequencing and prospective follow-up study of the natural history and brain magnetic resonance imaging (MRI) were performed. RESULTS Thirty-seven children were clinically diagnosed with cavitating leukoencephalopathies. Pathogenic or likely pathogenic mutations in eight genes were identified in 31 individuals (83.78%): IBA57 (17/37), NDUFS1 (5/37), NDUFV1 (2/37), NDUFV2 (3/37), NDUFAF5 (1/37), LYRM7 (1/37), NDUFB8 (1/37), and GLRX5 (1/37). All genes were engaged in mitochondrial function. IBA57 was identified in half of children. Mutations in NDUFV2, NDUFAF5, NDUFB8, or GLRX5 were first found to be related to cavitating leukoencephalopathies. Follow-up with a median of 23.5 months (four to 107 months) was available. The median age at disease onset was 11 months. All cases presented acute or subacute onset, and the initial presentation was rapid motor regression in 35 cases. Thirty-five children (35/37) exhibited a stabilized or improved pattern. Cavities and high-intensity diffusion-weighted imaging signals were the common MRI features during the acute stage. Although clinically stable, 21 children had reserved high diffusion-weighted imaging signals for a long time. Patients with different gene mutations show different MRI patterns. CONCLUSIONS The study expands the number of genes involved in cavitating leukoencephalopathies to 22. IBA57 is the most common candidate gene. Most cases showed a stabilized or improved pattern after an acute or subacute onset, which is different from most other inherited metabolic diseases or leukodystrophies. More cases and a longer follow-up period are needed.
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Affiliation(s)
- Jie Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ming Liu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhongbin Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ling Zhou
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Weijing Kong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiangxi Xiao
- Department of Radiology, Peking University First Hospital, Beijing, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, China.
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McCormick EM, Zolkipli-Cunningham Z, Falk MJ. Mitochondrial disease genetics update: recent insights into the molecular diagnosis and expanding phenotype of primary mitochondrial disease. Curr Opin Pediatr 2018; 30:714-724. [PMID: 30199403 PMCID: PMC6467265 DOI: 10.1097/mop.0000000000000686] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW Primary mitochondrial disease (PMD) is a genetically and phenotypically diverse group of inherited energy deficiency disorders caused by impaired mitochondrial oxidative phosphorylation (OXPHOS) capacity. Mutations in more than 350 genes in both mitochondrial and nuclear genomes are now recognized to cause primary mitochondrial disease following every inheritance pattern. Next-generation sequencing technologies have dramatically accelerated mitochondrial disease gene discovery and diagnostic yield. Here, we provide an up-to-date review of recently identified, novel mitochondrial disease genes and/or pathogenic variants that directly impair mitochondrial structure, dynamics, and/or function. RECENT FINDINGS A review of PubMed publications was performed from the past 12 months that identified 16 new PMD genes and/or pathogenic variants, and recognition of expanded phenotypes for a wide variety of mitochondrial disease genes. SUMMARY Broad-based exome sequencing has become the standard first-line diagnostic approach for PMD. This has facilitated more rapid and accurate disease identification, and greatly expanded understanding of the wide spectrum of potential clinical phenotypes. A comprehensive dual-genome sequencing approach to PMD diagnosis continues to improve diagnostic yield, advance understanding of mitochondrial physiology, and provide strong potential to develop precision therapeutics targeted to diverse aspects of mitochondrial disease pathophysiology.
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Affiliation(s)
- Elizabeth M. McCormick
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
| | - Zarazuela Zolkipli-Cunningham
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
| | - Marni J. Falk
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
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18
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Rodenburg RJ. The functional genomics laboratory: functional validation of genetic variants. J Inherit Metab Dis 2018; 41:297-307. [PMID: 29445992 PMCID: PMC5959958 DOI: 10.1007/s10545-018-0146-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 01/10/2018] [Accepted: 01/18/2018] [Indexed: 02/06/2023]
Abstract
Currently, one of the main challenges in human molecular genetics is the interpretation of rare genetic variants of unknown clinical significance. A conclusive diagnosis is of importance for the patient to obtain certainty about the cause of the disease, for the clinician to be able to provide optimal care to the patient and to predict the disease course, and for the clinical geneticist for genetic counseling of the patient and family members. Conclusive evidence for pathogenicity of genetic variants is therefore crucial. This review gives an introduction to the problem of the interpretation of genetic variants of unknown clinical significance in view of the recent advances in genetic screening, and gives an overview of the possibilities for functional tests that can be performed to answer questions about the function of genes and the functional consequences of genetic variants ("functional genomics") in the field of inborn errors of metabolism (IEM), including several examples of functional genomics studies of mitochondrial disorders and several other IEM.
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Affiliation(s)
- Richard J Rodenburg
- Radboudumc, Radboud Center for Mitochondrial Medicine, 774 Translational Metabolic Laboratory, Department of Pediatrics, PO Box 9101, 6500HB, Nijmegen, The Netherlands.
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Fernandez-Vizarra E, Zeviani M. Mitochondrial complex III Rieske Fe-S protein processing and assembly. Cell Cycle 2018; 17:681-687. [PMID: 29243944 DOI: 10.1080/15384101.2017.1417707] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Regulation of the mitochondrial respiratory chain biogenesis is a matter of great interest because of its implications for mitochondrial disease. One of the mitochondrial disease genes recently discovered associated to encephalopathy and mitochondrial complex III (cIII) deficiency is TTC19. Our study of TTC19-deficient human and mouse models, has led us to propose a post-assembly quality control role or 'husbandry' function for this factor that is linked to Rieske Fe-S protein (UQCRFS1). UQCRFS1 is the last incorporated cIII subunit, and its presence is essential for enzymatic activity. During UQCRFS1 assembly, the precursor is cleaved and its N-terminal part remains bound to the complex, between the two core subunits (UQCRC1 and UQCRC2). In the absence of TTC19 there is a prominent accumulation of these UQCRFS1-derived N-terminal fragments that proved to be detrimental for cIII function. In this article we will discuss some ideas around the UQCRFS1 processing and assembly and its importance for the regulation of cIII activity and biogenesis.
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Affiliation(s)
- Erika Fernandez-Vizarra
- a MRC-Mitochondrial Biology Unit , University of Cambridge , Hills Road, CB2 0XY , Cambridge , UK
| | - Massimo Zeviani
- a MRC-Mitochondrial Biology Unit , University of Cambridge , Hills Road, CB2 0XY , Cambridge , UK
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