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Next generation sequencing of Tunisian Leigh syndrome patients reveals novel variations: impact for diagnosis and treatment. Biosci Rep 2022; 42:231779. [PMID: 36093993 PMCID: PMC9508526 DOI: 10.1042/bsr20220194] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 07/22/2022] [Accepted: 08/23/2022] [Indexed: 11/28/2022] Open
Abstract
Mitochondrial cytopathies, among which the Leigh syndrome (LS), are caused by variants either in the mitochondrial or the nuclear genome, affecting the oxidative phosphorylation process. The aim of the present study consisted in defining the molecular diagnosis of a group of Tunisian patients with LS. Six children, belonging to five Tunisian families, with clinical and imaging presentations suggestive of LS were recruited. Whole mitochondrial DNA and targeted next-generation sequencing of a panel of 281 nuclear genes involved in mitochondrial physiology were performed. Bioinformatic analyses were achieved in order to identify deleterious variations. A single m.10197G>A (p.Ala47Thr) variant was found in the mitochondrial MT-ND3 gene in one patient, while the others were related to autosomal homozygous variants: two c.1412delA (p.Gln471ArgfsTer42) and c.1264A>G (p.Thr422Ala) in SLC19A3, one c.454C>G (p.Pro152Ala) in SLC25A19 and one c.122G>A (p.Gly41Asp) in ETHE1. Our findings demonstrate the usefulness of genomic investigations to improve LS diagnosis in consanguineous populations and further allow for treating the patients harboring variants in SLC19A3 and SLC25A19 that contribute to thiamine transport, by thiamine and biotin supplementation. Considering the Tunisian genetic background, the newly identified variants could be screened in patients with similar clinical presentation in related populations.
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Marra F, Lunetti P, Curcio R, Lasorsa FM, Capobianco L, Porcelli V, Dolce V, Fiermonte G, Scarcia P. An Overview of Mitochondrial Protein Defects in Neuromuscular Diseases. Biomolecules 2021; 11:1633. [PMID: 34827632 PMCID: PMC8615828 DOI: 10.3390/biom11111633] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 11/18/2022] Open
Abstract
Neuromuscular diseases (NMDs) are dysfunctions that involve skeletal muscle and cause incorrect communication between the nerves and muscles. The specific causes of NMDs are not well known, but most of them are caused by genetic mutations. NMDs are generally progressive and entail muscle weakness and fatigue. Muscular impairments can differ in onset, severity, prognosis, and phenotype. A multitude of possible injury sites can make diagnosis of NMDs difficult. Mitochondria are crucial for cellular homeostasis and are involved in various metabolic pathways; for this reason, their dysfunction can lead to the development of different pathologies, including NMDs. Most NMDs due to mitochondrial dysfunction have been associated with mutations of genes involved in mitochondrial biogenesis and metabolism. This review is focused on some mitochondrial routes such as the TCA cycle, OXPHOS, and β-oxidation, recently found to be altered in NMDs. Particular attention is given to the alterations found in some genes encoding mitochondrial carriers, proteins of the inner mitochondrial membrane able to exchange metabolites between mitochondria and the cytosol. Briefly, we discuss possible strategies used to diagnose NMDs and therapies able to promote patient outcome.
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Affiliation(s)
- Federica Marra
- Department of Pharmacy, Health, and Nutritional Sciences, University of Calabria, 87036 Arcavacata di Rende, Italy; (F.M.); (R.C.); (V.D.)
| | - Paola Lunetti
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy; (P.L.); (L.C.)
| | - Rosita Curcio
- Department of Pharmacy, Health, and Nutritional Sciences, University of Calabria, 87036 Arcavacata di Rende, Italy; (F.M.); (R.C.); (V.D.)
| | - Francesco Massimo Lasorsa
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy; (F.M.L.); (V.P.)
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, 00155 Rome, Italy
| | - Loredana Capobianco
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy; (P.L.); (L.C.)
| | - Vito Porcelli
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy; (F.M.L.); (V.P.)
| | - Vincenza Dolce
- Department of Pharmacy, Health, and Nutritional Sciences, University of Calabria, 87036 Arcavacata di Rende, Italy; (F.M.); (R.C.); (V.D.)
| | - Giuseppe Fiermonte
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy; (F.M.L.); (V.P.)
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, National Research Council, 00155 Rome, Italy
| | - Pasquale Scarcia
- Laboratory of Biochemistry and Molecular Biology, Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy; (F.M.L.); (V.P.)
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3
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Mazumder GA, Uddin A, Chakraborty S. Analysis of codon usage bias in mitochondrial CO gene among platyhelminthes. Mol Biochem Parasitol 2021; 245:111410. [PMID: 34487743 DOI: 10.1016/j.molbiopara.2021.111410] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 08/19/2021] [Accepted: 08/27/2021] [Indexed: 11/17/2022]
Abstract
The phenomenon of non-uniform usage of the synonymous codons, where some codons are given more preference to others, is known as codon usage bias (CUB). CUB is known to be determined by two major evolutionary forces i.e. mutation pressure and selection. We used various approaches to understand the codon usage pattern in mitochondrial CO (MT-CO) genes involved in complex IV of the respiratory chain (RC) as no work was reported yet. Our present study revealed that CUB was relatively high and the coding sequences were rich in A and T. Correspondence analysis further indicated that A/T compositional properties under mutational pressure might be affecting the codon usage pattern and was different in different classes for MT-CO gene. A highly significant correlation between A% and A3%, T% and T3%, G% and G3%, C% and C3%, GC% and GC3% in all the classes indicated that compositional constraints under mutational pressure and natural selection might affect the CUB. Neutrality plot indicated that both natural selection and mutational bias affected the CUB, where, natural selection played the major role as compared to mutational pressure.
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Affiliation(s)
- Gulshana A Mazumder
- Department of Biotechnology, Assam University, Silchar, 788011, Assam, India
| | - Arif Uddin
- Moinul Hoque Choudhury Memorial Science College, Algapur, Hailakandi, 788150, Assam, India
| | - Supriyo Chakraborty
- Department of Biotechnology, Assam University, Silchar, 788011, Assam, India.
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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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Wang W, Sun Y, Lin Y, Xu X, Zhao D, Ji K, Li W, Zhao Y, Yan C. A novel nonsense variant in MT-CO3 causes MELAS syndrome. Neuromuscul Disord 2021; 31:558-565. [PMID: 33863631 DOI: 10.1016/j.nmd.2021.02.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 02/11/2021] [Accepted: 02/26/2021] [Indexed: 11/18/2022]
Abstract
Both mitochondrial and nuclear gene mutations can cause cytochrome c oxidase (COX, complex Ⅳ) dysfunction, leading to mitochondrial diseases. Although numerous diseases caused by defects of the COX subunits or COX assembly factors have been documented, clinical cases directly related to mitochondrial cytochrome c oxidase subunit 3 gene (MT-CO3) mutations are relatively rare. Here, we report a 47-year-old female patient presented with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. Muscle pathology revealed ragged-red fibres and remarkable COX-deficient muscle fibres. Muscle mitochondrial DNA sequencing analysis identified a novel MT-CO3 variant (m.9553G>A) that changed a highly conserved amino acid to a stop codon (p.Trp116*). This variant was heteroplasmic in multiple tissues, where the mutation load was 13% in oral epithelial cells, 89% in muscle samples, and not detectable in the peripheral blood lymphocytes. Single muscle fiber PCR analysis showed clear segregation of the mutation load with COX deficient fibres. Western blot analysis of the muscle samples revealed a significant decrease in the levels of COX1, COX2, COX3, COX4 and UQCRC2. COX respiration activity was remarkably reduced (58.84%) relative to the controls according to spectrophotometric assays. Taken together, our results indicated that this m.9553G>A variant may be responsible for the MELAS symdrome in the proband by affecting the stability and function of COX. The study expands the clinical and molecular spectrum of COX3-specific mitochondrial diseases.
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Affiliation(s)
- Wei Wang
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road Jinan, Jinan, Shandong 250012 China
| | - Yuan Sun
- Department of Neurology, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, Shandong 266035 China
| | - Yan Lin
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road Jinan, Jinan, Shandong 250012 China
| | - Xuebi Xu
- Department of Neurology, First Affiliated Hospital of Wenzhou Medical University, Nanbaixiang Street, Ouhai District, Wenzhou 325000, China
| | - Dandan Zhao
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road Jinan, Jinan, Shandong 250012 China
| | - Kunqian Ji
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road Jinan, Jinan, Shandong 250012 China.
| | - Wei Li
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road Jinan, Jinan, Shandong 250012 China
| | - Yuying Zhao
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road Jinan, Jinan, Shandong 250012 China
| | - Chuanzhu Yan
- Research Institute of Neuromuscular and Neurodegenerative Diseases and Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, No. 107 West Wenhua Road Jinan, Jinan, Shandong 250012 China; Department of Neurology, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, Shandong 266035 China; Mitochondrial Medicine Laboratory, Qilu Hospital (Qingdao), Shandong University, Qingdao, Shandong 266035 China; Brain Science Research Institute, Shandong University, Jinan, Shandong 250000, China.
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6
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Mitochondrial Structure and Bioenergetics in Normal and Disease Conditions. Int J Mol Sci 2021; 22:ijms22020586. [PMID: 33435522 PMCID: PMC7827222 DOI: 10.3390/ijms22020586] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are ubiquitous intracellular organelles found in almost all eukaryotes and involved in various aspects of cellular life, with a primary role in energy production. The interest in this organelle has grown stronger with the discovery of their link to various pathologies, including cancer, aging and neurodegenerative diseases. Indeed, dysfunctional mitochondria cannot provide the required energy to tissues with a high-energy demand, such as heart, brain and muscles, leading to a large spectrum of clinical phenotypes. Mitochondrial defects are at the origin of a group of clinically heterogeneous pathologies, called mitochondrial diseases, with an incidence of 1 in 5000 live births. Primary mitochondrial diseases are associated with genetic mutations both in nuclear and mitochondrial DNA (mtDNA), affecting genes involved in every aspect of the organelle function. As a consequence, it is difficult to find a common cause for mitochondrial diseases and, subsequently, to offer a precise clinical definition of the pathology. Moreover, the complexity of this condition makes it challenging to identify possible therapies or drug targets.
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Mani S, Rao SN, Kumar MVK. G6036A substitution in mitochondrial COX I gene compromises cytochrome c oxidase activity in thiamine responsive Leigh syndrome patients. J Neurol Sci 2020; 415:116870. [PMID: 32428756 DOI: 10.1016/j.jns.2020.116870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/25/2022]
Abstract
Cytochrome c oxidase (COX) deficiency is known to be associated with Leigh syndrome (LS), however there are limited studies on genetic screening of mitochondrial (mt) DNA encoding COX genes as well as the functional validation of identified variants. In our previous studies, we cared for total 165 LS patients and analyzed the nucleotide variations across entire mt genome. We observed a high level of genetic heterogeneity in these patients. We identified various reported and novel variation across entire genome including COX genes. In our present study we have further studied and functionally validated the selected novel nucleotide variant of COX I and COX II gene using different in-silico tools and trans mitochondrial cybrid based assays. As a result of our study, G6036A (G45S) variant of COX I gene, reduced the COX activity in both spectrophotometric as well as In-gel BN-PAGE assays. FACS analysis also revealed this variant to affect the mitochondrial membrane potential in the respective cybrids. Interestingly most of our in-silico studies indicated that this variant might affect the secondary structure and confirmation of COX I protein. Thus we report the first missense mutation in the COX I gene of LS patients and justify its pathogenic role in these patients by different assays. Variant A7746G (N54K) in COX II gene was also predicted to affect the secondary structure as well as stability of COX II protein. Though, the effect of this variant was not significant, however it will be interesting to investigate its significance by other assays in future.
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Affiliation(s)
- Shalini Mani
- Department of Biotechnology, Centre for Emerging Diseases, Jaypee Institute of Information Technology, Noida 201301, India; Centre for Cellular and Molecular Biology, Hyderabad 500007, India.
| | - S Narasimha Rao
- Government Institute of Child Health, Niloufer Hospital for Women and Children, Red Hills, Hyderabad, India
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Aravintha Siva M, Mahalakshmi R, Bhakta-Guha D, Guha G. Gene therapy for the mitochondrial genome: Purging mutations, pacifying ailments. Mitochondrion 2018; 46:195-208. [PMID: 29890303 DOI: 10.1016/j.mito.2018.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 05/24/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022]
Abstract
In the recent years, the reported cases of mitochondrial disorders have reached a colossal number. These disorders spawn a sundry of pathological conditions, which lead to pernicious symptoms and even fatality. Due to the unpredictable etiologies, mitochondrial diseases are putatively referred to as "mystondria" (mysterious diseases of mitochondria). Although present-day research has greatly improved our understanding of mitochondrial disorders, effective therapeutic interventions are still at the precursory stage. The conundrum becomes further complicated because these pathologies might occur due to either mitochondrial DNA (mtDNA) mutations or due to mutations in the nuclear DNA (nDNA), or both. While correcting nDNA mutations by using gene therapy (replacement of defective genes by delivering wild-type (WT) ones into the host cell, or silencing a dominant mutant allele that is pathogenic) has emerged as a promising strategy to address some mitochondrial diseases, the complications in correcting the defects of mtDNA in order to renovate mitochondrial functions have remained a steep challenge. In this review, we focus specifically on the selective gene therapy strategies that have demonstrated prospects in targeting the pathological mutations in the mitochondrial genome, thereby treating mitochondrial ailments.
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Affiliation(s)
- M Aravintha Siva
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | - R Mahalakshmi
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | - Dipita Bhakta-Guha
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
| | - Gunjan Guha
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
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Maalej M, Kammoun T, Alila-Fersi O, Kharrat M, Ammar M, Felhi R, Mkaouar-Rebai E, Keskes L, Hachicha M, Fakhfakh F. Cytochrome C oxydase deficiency: SURF1 gene investigation in patients with Leigh syndrome. Biochem Biophys Res Commun 2018; 497:1043-1048. [PMID: 29481804 DOI: 10.1016/j.bbrc.2018.02.169] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 02/22/2018] [Indexed: 01/26/2023]
Abstract
Leigh syndrome (LS) is a rare progressive neurodegenerative disorder occurring in infancy. The most common clinical signs reported in LS are growth retardation, optic atrophy, ataxia, psychomotor retardation, dystonia, hypotonia, seizures and respiratory disorders. The paper reported a manifestation of 3 Tunisian patients presented with LS syndrome. The aim of this study is the MT[HYPHEN]ATP6 and SURF1 gene screening in Tunisian patients affected with classical Leigh syndrome and the computational investigation of the effect of detected mutations on its structure and functions by clinical and bioinformatics analyses. After clinical investigations, three Tunisian patients were tested for mutations in both MT-ATP6 and SURF1 genes by direct sequencing followed by in silico analyses to predict the effects of sequence variation. The result of mutational analysis revealed the absence of mitochondrial mutations in MT-ATP6 gene and the presence of a known homozygous splice site mutation c.516-517delAG in sibling patients added to the presence of a novel double het mutations in LS patient (c.752-18 A > C/c. c.751 + 16G > A). In silico analyses of theses intronic variations showed that it could alters splicing processes as well as SURF1 protein translation. Leigh syndrome (LS) is a rare progressive neurodegenerative disorder occurring in infancy. The most common clinical signs reported in LS are growth retardation, optic atrophy, ataxia, psychomotor retardation, dystonia, hypotonia, seizures and respiratory disorders. The paper reported a manifestation of 3 Tunisian patients presented with LS syndrome. The aim of this study is MT-ATP6 and SURF1 genes screening in Tunisian patients affected with classical Leigh syndrome and the computational investigation of the effect of detected mutations on its structure and functions. After clinical investigations, three Tunisian patients were tested for mutations in both MT-ATP6 and SURF1 genes by direct sequencing followed by in silico analysis to predict the effects of sequence variation. The result of mutational analysis revealed the absence of mitochondrial mutations in MT-ATP6 gene and the presence of a known homozygous splice site mutation c.516-517delAG in sibling patients added to the presence of a novel double het mutations in LS patient (c.752-18 A>C/ c.751+16G>A). In silico analysis of theses intronic vaiations showed that it could alters splicing processes as well as SURF1 protein translation.
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Affiliation(s)
- Marwa Maalej
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia.
| | - Thouraya Kammoun
- Service de Pédiatrie, C.H.U. Hedi Chaker, University of Sfax, Tunisia
| | - Olfa Alila-Fersi
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Marwa Kharrat
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Marwa Ammar
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Rahma Felhi
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Emna Mkaouar-Rebai
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Leila Keskes
- Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Mongia Hachicha
- Service de Pédiatrie, C.H.U. Hedi Chaker, University of Sfax, Tunisia
| | - Faiza Fakhfakh
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia.
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Klink GV, Golovin AV, Bazykin GA. Substitutions into amino acids that are pathogenic in human mitochondrial proteins are more frequent in lineages closely related to human than in distant lineages. PeerJ 2017; 5:e4143. [PMID: 29250469 PMCID: PMC5731343 DOI: 10.7717/peerj.4143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/16/2017] [Indexed: 11/23/2022] Open
Abstract
Propensities for different amino acids within a protein site change in the course of evolution, so that an amino acid deleterious in a particular species may be acceptable at the same site in a different species. Here, we study the amino acid-changing variants in human mitochondrial genes, and analyze their occurrence in non-human species. We show that substitutions giving rise to such variants tend to occur in lineages closely related to human more frequently than in more distantly related lineages, indicating that a human variant is more likely to be deleterious in more distant species. Unexpectedly, substitutions giving rise to amino acids that correspond to alleles pathogenic in humans also more frequently occur in more closely related lineages. Therefore, a pathogenic variant still tends to be more acceptable in human mitochondria than a variant that may only be fit after a substantial perturbation of the protein structure.
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Affiliation(s)
- Galya V. Klink
- Sector of Molecular Evolution, Institute for Information Transmission Problems (Kharkevich Institute) of the Russian Academy of Sciences, Moscow, Russian Federation
| | - Andrey V. Golovin
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Georgii A. Bazykin
- Sector of Molecular Evolution, Institute for Information Transmission Problems (Kharkevich Institute) of the Russian Academy of Sciences, Moscow, Russian Federation
- Center for Data-Intensive Biomedicine and Biotechnology, Skolkovo Institute of Science and Technology, Skolkovo, Russian Federation
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11
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Gao WY, Li D, Cai DE, Huang XY, Zheng BY, Huang YH, Chen ZX, Wang XZ. Hepatitis B virus X protein sensitizes HL-7702 cells to oxidative stress-induced apoptosis through modulation of the mitochondrial permeability transition pore. Oncol Rep 2016; 37:48-56. [PMID: 27840960 PMCID: PMC5355673 DOI: 10.3892/or.2016.5225] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 06/10/2016] [Indexed: 12/14/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection is a leading cause of liver cirrhosis and cancer. Among the pathogenic factors of HBV, HBV X protein (HBx) is attracting increased attention. Although it is documented that HBx is a multifunctional regulator that modulates cell inflammation and apoptosis, the exact mechanism remains controversial. In the present study, we explored the effect of HBx on oxidative stress-induced apoptosis in normal liver cell line, HL-7702. Our results showed that the existence of HBx affected mitochondrial biogenesis by modulating the opening of the mitochondrial permeability transition pore (MPTP). Notably, this phenomenon was associated with a pronounced translocation of Bax from the cytosol to the mitochondria during the period of exposure to oxidative stress with a release of cytochrome c and activation of cleaved caspase-3 and PARP. Moreover, MPTP blockage with cyclosporin A prevented the translocation of Bax, and inhibited oxidative stress-induced apoptotic killing in the HBx-expressing HL-7702 cells. Our findings suggest that HBx exhibits pro-apoptotic effects upon normal liver cells following exposure to oxidative stress by modulating the MPTP gateway.
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Affiliation(s)
- Wen-Yu Gao
- Department of Gastroenterology, Fujian Medical University Union Hospital, Fujian 350001, P.R. China
| | - Dan Li
- Department of Gastroenterology, Fujian Medical University Union Hospital, Fujian 350001, P.R. China
| | - De-En Cai
- Graduate School, Fujian Medical University, Fujian 350001, P.R. China
| | - Xiao-Yun Huang
- Graduate School, Fujian Medical University, Fujian 350001, P.R. China
| | - Bi-Yun Zheng
- Department of Gastroenterology, Fujian Medical University Union Hospital, Fujian 350001, P.R. China
| | - Yue-Hong Huang
- Department of Gastroenterology, Fujian Medical University Union Hospital, Fujian 350001, P.R. China
| | - Zhi-Xin Chen
- Department of Gastroenterology, Fujian Medical University Union Hospital, Fujian 350001, P.R. China
| | - Xiao-Zhong Wang
- Department of Gastroenterology, Fujian Medical University Union Hospital, Fujian 350001, P.R. China
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Rak M, Bénit P, Chrétien D, Bouchereau J, Schiff M, El-Khoury R, Tzagoloff A, Rustin P. Mitochondrial cytochrome c oxidase deficiency. Clin Sci (Lond) 2016; 130:393-407. [PMID: 26846578 PMCID: PMC4948581 DOI: 10.1042/cs20150707] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
As with other mitochondrial respiratory chain components, marked clinical and genetic heterogeneity is observed in patients with a cytochrome c oxidase deficiency. This constitutes a considerable diagnostic challenge and raises a number of puzzling questions. So far, pathological mutations have been reported in more than 30 genes, in both mitochondrial and nuclear DNA, affecting either structural subunits of the enzyme or proteins involved in its biogenesis. In this review, we discuss the possible causes of the discrepancy between the spectacular advances made in the identification of the molecular bases of cytochrome oxidase deficiency and the lack of any efficient treatment in diseases resulting from such deficiencies. This brings back many unsolved questions related to the frequent delay of clinical manifestation, variable course and severity, and tissue-involvement often associated with these diseases. In this context, we stress the importance of studying different models of these diseases, but also discuss the limitations encountered in most available disease models. In the future, with the possible exception of replacement therapy using genes, cells or organs, a better understanding of underlying mechanism(s) of these mitochondrial diseases is presumably required to develop efficient therapy.
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Affiliation(s)
- Malgorzata Rak
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 1141, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France Faculté de Médecine Denis Diderot, Université Paris Diderot-Paris 7, Site Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France
| | - Paule Bénit
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 1141, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France Faculté de Médecine Denis Diderot, Université Paris Diderot-Paris 7, Site Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France
| | - Dominique Chrétien
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 1141, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France Faculté de Médecine Denis Diderot, Université Paris Diderot-Paris 7, Site Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France
| | - Juliette Bouchereau
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 1141, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France Faculté de Médecine Denis Diderot, Université Paris Diderot-Paris 7, Site Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France
| | - Manuel Schiff
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 1141, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France Faculté de Médecine Denis Diderot, Université Paris Diderot-Paris 7, Site Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France Reference Center for Inherited Metabolic Diseases, Hôpital Robert Debré, Assistance Publique-Hôpitaux de Paris, 48 Boulevard Sérurier, 75019 Paris, France
| | - Riyad El-Khoury
- American University of Beirut Medical Center, Department of Pathology and Laboratory Medicine, Cairo Street, Hamra, Beirut, Lebanon
| | - Alexander Tzagoloff
- Biological Sciences Department, Columbia University, New York, NY 10027, U.S.A
| | - Pierre Rustin
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 1141, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France Faculté de Médecine Denis Diderot, Université Paris Diderot-Paris 7, Site Robert Debré, 48 Boulevard Sérurier, 75019 Paris, France
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Cordero MD, Alcocer-Gómez E, Marín-Aguilar F, Rybkina T, Cotán D, Pérez-Pulido A, Alvarez-Suarez JM, Battino M, Sánchez-Alcazar JA, Carrión AM, Culic O, Navarro-Pando JM, Bullón P. Mutation in cytochrome b gene of mitochondrial DNA in a family with fibromyalgia is associated with NLRP3-inflammasome activation. J Med Genet 2015; 53:113-22. [PMID: 26566881 DOI: 10.1136/jmedgenet-2015-103392] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/08/2015] [Indexed: 01/24/2023]
Abstract
BACKGROUND Fibromyalgia (FM) is a worldwide diffuse musculoskeletal chronic pain condition that affects up to 5% of the general population. Many symptoms associated with mitochondrial diseases are reported in patients with FM such as exercise intolerance, fatigue, myopathy and mitochondrial dysfunction. In this study, we report a mutation in cytochrome b gene of mitochondrial DNA (mtDNA) in a family with FM with inflammasome complex activation. METHODS mtDNA from blood cells of five patients with FM were sequenced. We clinically and genetically characterised a patient with FM and family with a new mutation in mtCYB. Mitochondrial mutation phenotypes were determined in skin fibroblasts and transmitochondrial cybrids. RESULTS After mtDNA sequence in patients with FM, we found a mitochondrial homoplasmic mutation m.15804T>C in the mtCYB gene in a patient and family, which was maternally transmitted. Mutation was observed in several tissues and skin fibroblasts showed a very significant mitochondrial dysfunction and oxidative stress. Increased NLRP3-inflammasome complex activation was observed in blood cells from patient and family. CONCLUSIONS We propose further studies on mtDNA sequence analysis in patients with FM with evidences for maternal inheritance. The presence of similar symptoms in mitochondrial myopathies could unmask mitochondrial diseases among patients with FM. On the other hand, the inflammasome complex activation by mitochondrial dysfunction could be implicated in the pathophysiology of mitochondrial diseases.
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Affiliation(s)
- Mario D Cordero
- IBiS Institute of Biomedicine of Seville, University Hospital Virgen del Rocío-CSIC-University of Seville, Sevilla, Spain Research Laboratory, Oral Medicine Department, University of Sevilla, Sevilla, Spain
| | - Elísabet Alcocer-Gómez
- Centro Andaluz de Biología del Desarrollo (CABD), Universidad Pablo de Olavide-CSIC-Junta de Andalucía, Sevilla, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Sevilla, Spain
| | - Fabiola Marín-Aguilar
- IBiS Institute of Biomedicine of Seville, University Hospital Virgen del Rocío-CSIC-University of Seville, Sevilla, Spain
| | - Tatyana Rybkina
- División de Neurociencias, Universidad Pablo de Olavide de Sevilla, Sevilla, Spain
| | - David Cotán
- Centro Andaluz de Biología del Desarrollo (CABD), Universidad Pablo de Olavide-CSIC-Junta de Andalucía, Sevilla, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Sevilla, Spain
| | - Antonio Pérez-Pulido
- Centro Andaluz de Biología del Desarrollo (CABD), Universidad Pablo de Olavide-CSIC-Junta de Andalucía, Sevilla, Spain
| | - José Miguel Alvarez-Suarez
- Escuela de Medicina Veterinaria y Zootecnia, Facultad de Ciencias de la Salud, Universidad de Las Américas, Quito, Ecuador
| | - Maurizio Battino
- Dipartimento di Scienze Cliniche Specialistiche ed Odontostomatologiche-Sez. Biochimica, Università Politecnica delle Marche, Ancona, Italy
| | - José Antonio Sánchez-Alcazar
- Centro Andaluz de Biología del Desarrollo (CABD), Universidad Pablo de Olavide-CSIC-Junta de Andalucía, Sevilla, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Sevilla, Spain
| | - Angel M Carrión
- División de Neurociencias, Universidad Pablo de Olavide de Sevilla, Sevilla, Spain
| | - Ognjen Culic
- Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia
| | - José M Navarro-Pando
- Unidad de Reproducción Humana y Cirugía Endoscópica, Instituto para el Estudio de la Biología de la Reproducción Humana (INEBIR), Sevilla, Spain
| | - Pedro Bullón
- IBiS Institute of Biomedicine of Seville, University Hospital Virgen del Rocío-CSIC-University of Seville, Sevilla, Spain Research Laboratory, Oral Medicine Department, University of Sevilla, Sevilla, Spain
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Alteration of structure and function of ATP synthase and cytochrome c oxidase by lack of Fo-a and Cox3 subunits caused by mitochondrial DNA 9205delTA mutation. Biochem J 2015; 466:601-11. [PMID: 25588698 DOI: 10.1042/bj20141462] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mutations in the MT-ATP6 gene are frequent causes of severe mitochondrial disorders. Typically, these are missense mutations, but another type is represented by the 9205delTA microdeletion, which removes the stop codon of the MT-ATP6 gene and affects the cleavage site in the MT-ATP8/MT-ATP6/MT-CO3 polycistronic transcript. This interferes with the processing of mRNAs for the Atp6 (Fo-a) subunit of ATP synthase and the Cox3 subunit of cytochrome c oxidase (COX). Two cases described so far presented with strikingly different clinical phenotypes-mild transient lactic acidosis or fatal encephalopathy. To gain more insight into the pathogenic mechanism, we prepared 9205delTA cybrids with mutation load ranging between 52 and 99% and investigated changes in the structure and function of ATP synthase and the COX. We found that 9205delTA mutation strongly reduces the levels of both Fo-a and Cox3 proteins. Lack of Fo-a alters the structure but not the content of ATP synthase, which assembles into a labile, ∼60 kDa smaller, complex retaining ATP hydrolytic activity but which is unable to synthesize ATP. In contrast, lack of Cox3 limits the biosynthesis of COX but does not alter the structure of the enzyme. Consequently, the diminished mitochondrial content of COX and non-functional ATP synthase prevent most mitochondrial ATP production. The biochemical effects caused by the 9205delTA microdeletion displayed a pronounced threshold effect above ∼90% mutation heteroplasmy. We observed a linear relationship between the decrease in subunit Fo-a or Cox3 content and the functional presentation of the defect. Therefore we conclude that the threshold effect originated from a gene-protein level.
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Zou LY, Zheng BY, Fang XF, Li D, Huang YH, Chen ZX, Zhou LY, Wang XZ. HBx co-localizes with COXIII in HL-7702 cells to upregulate mitochondrial function and ROS generation. Oncol Rep 2015; 33:2461-7. [PMID: 25778742 DOI: 10.3892/or.2015.3852] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 02/19/2015] [Indexed: 11/05/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is one of the most common malignant diseases, and HBx leads to the development of HBV-associated HCC. Mitochondria are key organelles that regulate apoptosis, cellular energetics and signal transduction pathways, and are the source of HBx-induced reactive oxygen species (ROS). Recent findings have shown that HBx interacts with the inner mitochondrial membrane protein, COXIII, via the yeast two-hybrid system, mating experiment and coimmunoprecipitation. The aim of the present study was to examine the co-localizaiton of HBx and COXIII in HL-7702 cells and to investigate ensuing alterations of mitochondrial function. An HL-7702 cell line stably expressing the HBx gene by lentivirus vectors was constructed. Confocal microscopy was utilized to assess the interaction between HBx protein and COXIII. Expression of COXIII, activities of cytochrome c oxidase (COX) and the mitochondrial membrane potential, which were functionally relevant to the HBx protein-COXIII interaction, were investigated in cell cultures. Moreover, the intracellular ROS levels were detected by flow cytometry. The results demonstrated that HBx co-localized with the inner mitochondrial protein, COXIII, in HL-7702 cells, causing the upregulation of COXIII protein expression as well as COX activity. However, HBx did not alter the mitochondrial membrane potential and mitochondria exhibited only slight swelling in HL-7702-HBx cells. Moreover, HBx elevated the generation of mitochondrial ROS in HL-7702-HBx cells. The main finding of the present study was that the co-localization of HBx and COXIII leads to upregulation of the mitochondrial function and ROS generation, which are associated with the oncogenesis of HBV-associated HCC.
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Affiliation(s)
- Lai-Yu Zou
- Department of Infection, Union Hospital of Fujian Medical University, Gulou, Fuzhou, Fujian 350001, P.R. China
| | - Bi-Yun Zheng
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Gulou, Fuzhou, Fujian 350001, P.R. China
| | - Xue-Fen Fang
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Gulou, Fuzhou, Fujian 350001, P.R. China
| | - Dan Li
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Gulou, Fuzhou, Fujian 350001, P.R. China
| | - Yue-Hong Huang
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Gulou, Fuzhou, Fujian 350001, P.R. China
| | - Zhi-Xin Chen
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Gulou, Fuzhou, Fujian 350001, P.R. China
| | - Lin-Ying Zhou
- Laboratory of Electron Microscopy, Fujian Medical University, Gulou, Fuzhou, Fujian 350001, P.R. China
| | - Xiao-Zhong Wang
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Gulou, Fuzhou, Fujian 350001, P.R. China
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Zheng BY, Fang XF, Zou LY, Huang YH, Chen ZX, Li D, Zhou LY, Chen H, Wang XZ. The co-localization of HBx and COXIII upregulates COX-2 promoting HepG2 cell growth. Int J Oncol 2014; 45:1143-50. [PMID: 24938358 DOI: 10.3892/ijo.2014.2499] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 05/27/2014] [Indexed: 11/06/2022] Open
Abstract
HBx is a multifunctional regulator that interacts with host factors to contribute to the development of hepatocellular carcinoma. In this study, to explore the co-localization of HBx and COXIII in HepG2 cells and to investigate the molecular mechanism of HBx in HepG2 cell growth promotion, we first constructed a HepG2 cell line stably expressing the HBx gene in vitro by lentivirus vectors. In addition, we found that HBx co-localized with the inner mitochondrial protein, COXIII, in HepG2 cells by confocal laser scanning microscopy. It led to changes of mitochondrial biogenesis and morphology, including upregulation of COXIII protein expression, increased cytochrome c oxidase activity and higher mitochondrial membrane potential. The upregulation of COX-2 caused by HBx through generation of mitochondrial reactive oxygen species promoted cell growth. Thus, we conclude that co-localization of HBx and COXIII leads to upregulation of COX-2 that promotes HepG2 cell growth. Such a mechanism provides deeper insights into the molecular mechanism of HBV-associated hepatocellular carcinoma.
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Affiliation(s)
- Bi-Yun Zheng
- Graduate School, Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Xue-Fen Fang
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Lai-Yu Zou
- Department of Infection, Union Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Yue-Hong Huang
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Zhi-Xin Chen
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Dan Li
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Lin-Ying Zhou
- Laboratory of Electron Microscopy, Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Hao Chen
- Department of Gastroenterology, The Third Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350108, P.R. China
| | - Xiao-Zhong Wang
- Department of Gastroenterology, Union Hospital of Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
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Recent mitochondrial DNA mutations increase the risk of developing common late-onset human diseases. PLoS Genet 2014; 10:e1004369. [PMID: 24852434 PMCID: PMC4031051 DOI: 10.1371/journal.pgen.1004369] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/24/2014] [Indexed: 02/01/2023] Open
Abstract
Mitochondrial DNA (mtDNA) is highly polymorphic at the population level, and specific mtDNA variants affect mitochondrial function. With emerging evidence that mitochondrial mechanisms are central to common human diseases, it is plausible that mtDNA variants contribute to the “missing heritability” of several complex traits. Given the central role of mtDNA genes in oxidative phosphorylation, the same genetic variants would be expected to alter the risk of developing several different disorders, but this has not been shown to date. Here we studied 38,638 individuals with 11 major diseases, and 17,483 healthy controls. Imputing missing variants from 7,729 complete mitochondrial genomes, we captured 40.41% of European mtDNA variation. We show that mtDNA variants modifying the risk of developing one disease also modify the risk of developing other diseases, thus providing independent replication of a disease association in different case and control cohorts. High-risk alleles were more common than protective alleles, indicating that mtDNA is not at equilibrium in the human population, and that recent mutations interact with nuclear loci to modify the risk of developing multiple common diseases. There is a growing body of evidence indicating that mitochondrial dysfunction, a result of genetic variation in the mitochondrial genome, is a critical component in the aetiology of a number of complex traits. Here, we take advantage of recent technical and methodological advances to examine the role of common mitochondrial DNA variants in several complex diseases. By examining over 50,000 individuals, from 11 different diseases we show that mitochondrial DNA variants can both increase or decrease an individual's risk of disease, replicating and expanding upon several previously reported studies. Moreover, by analysing several large disease groups in tandem, we are able to show a commonality of association, with the same mitochondrial DNA variants associated with several distinct disease phenotypes. These shared genetic associations implicate a shared underlying functional effect, likely changing cellular energy, which manifests as distinct phenotypes. Our study confirms the important role that mitochondrial DNA variation plays on complex traits and additionally supports the utility of a GWAS-based approach for analysing mitochondrial genetics.
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Horan MP, Rumbley JN, Melvin RG, Le Couteur DG, Ballard JWO. Quaternary protein modeling to predict the function of DNA variation found in human mitochondrial cytochrome c oxidase. J Hum Genet 2013; 58:127-34. [DOI: 10.1038/jhg.2012.144] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Mkaouar-Rebai E, Chamkha I, Mezghani N, Ben Ayed I, Fakhfakh F. Screening of mitochondrial mutations in Tunisian patients with mitochondrial disorders: an overview study. ACTA ACUST UNITED AC 2013; 24:163-78. [PMID: 23301511 DOI: 10.3109/19401736.2012.748045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To investigate the spectrum of common mitochondrial mutations in Tunisia during the years of 2002-2012, 226 patients with mitochondrial disorders were clinically diagnosed with hearing loss, Leigh syndrome (LS), diabetes, cardiomyopathy, Kearns-Sayre syndrome (KSS), Pearson syndrome (PS), myopathy, mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes syndrome (MELAS) and Wolfram syndrome. Restriction fragment length polymorphism (PCR-RFLP), radioactive PCR, single specific primer-PCR (SSP-PCR) analysis and PCR-sequencing methods were used to identify the mutations. Two cases with m.1555A>G mutation and two families with the novel 12S rRNA m.735A>G transition were detected in patients with hearing loss. Three cases with m.8993T>G mutation, two patients with the novel m.5523T>G and m.5559A>G mutations in the tRNA(Trp) gene, and two individuals with the undescribed m.9478T>C mutation in the cytochrome c oxidase subunit III (COXIII) gene were found with LS. In addition, one case with hypertrophic cardiomyopathy and deafness presented the ND1 m.3395A>G mutation and the tRNA(Ile) m.4316A>G variation. Besides, multiple mitochondrial deletions were detected in patients with KSS, PS, and Wolfram syndrome. The m.14709T>C mutation in the tRNA(Glu) was reported in four maternally inherited diabetes and deafness patients and a novel tRNA(Val) m.1640A>G mutation was detected in a MELAS patient.
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Affiliation(s)
- Emna Mkaouar-Rebai
- Human Molecular Genetic Laboratory, Faculty of Medicine of Sfax, Avenue Magida Boulila, 3029 Sfax, Tunisia.
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DiMauro S, Tanji K, Schon EA. The Many Clinical Faces of Cytochrome c Oxidase Deficiency. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:341-57. [DOI: 10.1007/978-1-4614-3573-0_14] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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