1
|
Burr SP, Chinnery PF. Origins of tissue and cell-type specificity in mitochondrial DNA (mtDNA) disease. Hum Mol Genet 2024; 33:R3-R11. [PMID: 38779777 PMCID: PMC11112380 DOI: 10.1093/hmg/ddae059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 12/21/2023] [Accepted: 02/05/2024] [Indexed: 05/25/2024] Open
Abstract
Mutations of mitochondrial (mt)DNA are a major cause of morbidity and mortality in humans, accounting for approximately two thirds of diagnosed mitochondrial disease. However, despite significant advances in technology since the discovery of the first disease-causing mtDNA mutations in 1988, the comprehensive diagnosis and treatment of mtDNA disease remains challenging. This is partly due to the highly variable clinical presentation linked to tissue-specific vulnerability that determines which organs are affected. Organ involvement can vary between different mtDNA mutations, and also between patients carrying the same disease-causing variant. The clinical features frequently overlap with other non-mitochondrial diseases, both rare and common, adding to the diagnostic challenge. Building on previous findings, recent technological advances have cast further light on the mechanisms which underpin the organ vulnerability in mtDNA diseases, but our understanding is far from complete. In this review we explore the origins, current knowledge, and future directions of research in this area.
Collapse
Affiliation(s)
- Stephen P Burr
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, United Kingdom
| | - Patrick F Chinnery
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| |
Collapse
|
2
|
Tsyba N, Feng G, Grub LK, Held JP, Strozak AM, Burkewitz K, Patel MR. Tissue-specific heteroplasmy segregation is accompanied by a sharp mtDNA decline in Caenorhabditis elegans soma. iScience 2023; 26:106349. [PMID: 36968071 PMCID: PMC10031119 DOI: 10.1016/j.isci.2023.106349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/08/2022] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Mutations in the mitochondrial genome (mtDNA) can be pathogenic. Owing to the multi-copy nature of mtDNA, wild-type copies can compensate for the effects of mutant mtDNA. Wild-type copies available for compensation vary depending on the mutant load and the total copy number. Here, we examine both mutant load and copy number in the tissues of Caenorhabditis elegans. We found that neurons, but not muscles, have modestly higher mutant load than rest of the soma. We also uncovered different effect of aak-2 knockout on the mutant load in the two tissues. The most surprising result was a sharp decline in somatic mtDNA content over time. The scale of the copy number decline surpasses the modest shifts in mutant load, suggesting that it may exert a substantial effect on mitochondrial function. In summary, measuring both the copy number and the mutant load provides a more comprehensive view of the mutant mtDNA dynamics.
Collapse
Affiliation(s)
- Nikita Tsyba
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Gaomin Feng
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN37232, USA
| | - Lantana K. Grub
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - James P. Held
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Adrianna M. Strozak
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Kristopher Burkewitz
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN37232, USA
| | - Maulik R. Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN37232, USA
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN37232, USA
- Evolutionary Studies, Vanderbilt University, Nashville, TN37235, USA
| |
Collapse
|
3
|
Kohn EM, Taira C, Dobson H, Dias LDS, Okaa U, Wiesner DL, Wüthrich M, Klein BS. Variation in Host Resistance to Blastomyces dermatitidis: Potential Use of Genetic Reference Panels and Advances in Immunophenotyping of Diverse Mouse Strains. mBio 2022; 13:e0340021. [PMID: 35089087 PMCID: PMC8725596 DOI: 10.1128/mbio.03400-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 11/22/2021] [Indexed: 11/20/2022] Open
Abstract
Host genetic determinants that underpin variation in susceptibility to systemic fungal infection are poorly understood. Genes responsible for complex traits can be identified by correlating variation in phenotype with allele in founder strains of wild mice with known genetic variation, assembled in genetic reference panels. In this work, we describe wide natural variation in both primary and acquired resistance to experimental pulmonary blastomycosis in eight founder strains, including 129, A/J, BL/6, CAST, NOD, NZO, PWK, and WSB of the Collaborative Cross collection, and the inbred DBA strain. These differences in susceptibility across strains were accompanied by sharp differences in the accumulation and function of immune cells in the lungs. Immune perturbations were mapped by identifying reagents that phenotypically mark immune cell populations in the distinct strains of mice. In particular, we uncovered marked differences between BL/6 and DBA/2 mouse strains in the development of acquired resistance. Our findings highlight the potential value in using genetic reference panels of mice, and particularly the BXD (recombinant inbred strains of mice from a cross of C57BL/6J and DBA/2J mice) collection harboring a cross between resistant BL/6 and susceptible DBA/2 mice, for unveiling genes linked with host resistance to fungal infection. IMPORTANCE Host genetic variation significantly impacts vulnerability to infectious diseases. While host variation in susceptibility to fungal infection with dimorphic fungi has long been recognized, genes that underpin this variation are poorly understood. We used a collection of seven mouse strains that represent nearly 90% of the genetic variation in mice to identify genetic variability among the strains in resistance to pulmonary infection with the dimorphic fungus Blastomyces dermatitidis. We analyzed differences between the strains in innate resistance by infecting naive mice and in acquired resistance by infecting vaccinated mice. We identified extreme variations in both innate and acquired resistance among the strains. In particular, we found sharp differences between C57BL/6 and DBA/2 strains in the ability to acquire vaccine-induced resistance. We also identified commercial reagents that allowed the phenotyping of immune cells from this strain collection of mice. Because there are additional mice harboring a genetic cross of the C57BL/6 and DBA/2 strains (BXD collection), such mice will permit future investigations to identify the genes that underlie differences in the ability to acquire resistance to infection.
Collapse
Affiliation(s)
- Elaine M. Kohn
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Cleison Taira
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Hanah Dobson
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Lucas Dos Santos Dias
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Uju Okaa
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Darin L. Wiesner
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Marcel Wüthrich
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Bruce S. Klein
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
- Department of Internal Medicine, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin—Madison, Madison, Wisconsin, USA
| |
Collapse
|
4
|
Limoges MA, Cloutier M, Nandi M, Ilangumaran S, Ramanathan S. The GIMAP Family Proteins: An Incomplete Puzzle. Front Immunol 2021; 12:679739. [PMID: 34135906 PMCID: PMC8201404 DOI: 10.3389/fimmu.2021.679739] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/12/2021] [Indexed: 12/19/2022] Open
Abstract
Overview: Long-term survival of T lymphocytes in quiescent state is essential to maintain their cell numbers in secondary lymphoid organs and in peripheral circulation. In the BioBreeding diabetes-prone strain of rats (BB-DP), loss of functional GIMAP5 (GTPase of the immune associated nucleotide binding protein 5) results in profound peripheral T lymphopenia. This discovery heralded the identification of a new family of proteins initially called Immune-associated nucleotide binding protein (IAN) family. In this review we will use ‘GIMAP’ to refer to this family of proteins. Recent studies suggest that GIMAP proteins may interact with each other and also be involved in the movement of the cellular cargo along the cytoskeletal network. Here we will summarize the current knowledge on the characteristics and functions of GIMAP family of proteins.
Collapse
Affiliation(s)
- Marc-André Limoges
- Department of Immunology and Cell Biology, Faculty of Medicine and Health Sciences, Université de Sherbrooke and CRCHUS, Sherbrooke, QC, Canada
| | - Maryse Cloutier
- Department of Immunology and Cell Biology, Faculty of Medicine and Health Sciences, Université de Sherbrooke and CRCHUS, Sherbrooke, QC, Canada
| | - Madhuparna Nandi
- Department of Immunology and Cell Biology, Faculty of Medicine and Health Sciences, Université de Sherbrooke and CRCHUS, Sherbrooke, QC, Canada
| | - Subburaj Ilangumaran
- Department of Immunology and Cell Biology, Faculty of Medicine and Health Sciences, Université de Sherbrooke and CRCHUS, Sherbrooke, QC, Canada
| | - Sheela Ramanathan
- Department of Immunology and Cell Biology, Faculty of Medicine and Health Sciences, Université de Sherbrooke and CRCHUS, Sherbrooke, QC, Canada
| |
Collapse
|
5
|
Røyrvik EC, Johnston IG. MtDNA sequence features associated with 'selfish genomes' predict tissue-specific segregation and reversion. Nucleic Acids Res 2020; 48:8290-8301. [PMID: 32716035 PMCID: PMC7470939 DOI: 10.1093/nar/gkaa622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/25/2020] [Accepted: 07/15/2020] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial DNA (mtDNA) encodes cellular machinery vital for cell and organism survival. Mutations, genetic manipulation, and gene therapies may produce cells where different types of mtDNA coexist in admixed populations. In these admixtures, one mtDNA type is often observed to proliferate over another, with different types dominating in different tissues. This ‘segregation bias’ is a long-standing biological mystery that may pose challenges to modern mtDNA disease therapies, leading to substantial recent attention in biological and medical circles. Here, we show how an mtDNA sequence’s balance between replication and transcription, corresponding to molecular ‘selfishness’, in conjunction with cellular selection, can potentially modulate segregation bias. We combine a new replication-transcription-selection (RTS) model with a meta-analysis of existing data to show that this simple theory predicts complex tissue-specific patterns of segregation in mouse experiments, and reversion in human stem cells. We propose the stability of G-quadruplexes in the mtDNA control region, influencing the balance between transcription and replication primer formation, as a potential molecular mechanism governing this balance. Linking mtDNA sequence features, through this molecular mechanism, to cellular population dynamics, we use sequence data to obtain and verify the sequence-specific predictions from this hypothesis on segregation behaviour in mouse and human mtDNA.
Collapse
Affiliation(s)
- Ellen C Røyrvik
- Department of Clinical Science, University of Bergen, Norway.,K.G. Jebsen Center for Autoimmune Diseases, University of Bergen, Norway
| | - Iain G Johnston
- Department of Mathematics, University of Bergen, Norway.,Alan Turing Institute, London, UK
| |
Collapse
|
6
|
van den Ameele J, Li AY, Ma H, Chinnery PF. Mitochondrial heteroplasmy beyond the oocyte bottleneck. Semin Cell Dev Biol 2020; 97:156-166. [DOI: 10.1016/j.semcdb.2019.10.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 09/17/2019] [Accepted: 10/01/2019] [Indexed: 12/31/2022]
|
7
|
Pan J, Wang L, Lu C, Zhu Y, Min Z, Dong X, Sha H. Matching Mitochondrial DNA Haplotypes for Circumventing Tissue-Specific Segregation Bias. iScience 2019; 13:371-379. [PMID: 30897510 PMCID: PMC6426714 DOI: 10.1016/j.isci.2019.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/13/2019] [Accepted: 03/01/2019] [Indexed: 02/01/2023] Open
Abstract
Mitochondrial DNA (mtDNA) segregation associated with donor-recipient mtDNA mismatch in mitochondria replacement therapy leads to unknown risks. Here, to explore whether matching mtDNA haplotypes contributes to ameliorating segregation, we reproduced various degrees of heteroplasmic mice with three single nucleotide polymorphisms to monitor segregation severity. “Segregation” presented in tissues of heteroplasmic mice containing low-level donor mtDNA heteroplasmy, and disappeared as donor mtDNA heteroplasmy levels ascended. Meanwhile, we found that distribution of donor mtDNA among the blastomeres of preimplantation embryos from the heteroplasmic mice shared the same tendency as that in adult tissues. Statistical analysis showed that no selective replication of donor mtDNA occurred during lifespan. Tracking donor mtDNA distribution showed that uneven distribution of donor mtDNA among embryonic blastomeres gradually became even as donor mtDNA heteroplasmy increased, indicating that the “segregation” in tissues was inherited from the uneven distribution. Our finding suggested that donor-recipient mtDNA matching could circumvent segregation in mitochondria replacement therapy. Matching mitochondrial DNA haplotypes make the nucleus treat different mtDNA the same Similar mtDNA haplotypes prevents tissue-specific segregation bias Low level of mtDNA heteroplasmy results in uneven inheritance rather than segregation
Collapse
Affiliation(s)
- Jianxin Pan
- Reproductive Medicine Center, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Li Wang
- Key Lab of Synthetic Biology of CAS, Shanghai Institute for Biological Sciences, Shanghai Research Center of Biotech., Chinese Academy of Sciences, 500 Caobao Road, Shanghai 200233, China
| | - Charles Lu
- Reproductive Medicine Center, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China; Washington University in St. Louis, Saint Louis 63110, USA
| | - Yanming Zhu
- Reproductive Medicine Center, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhunyuan Min
- Reproductive Medicine Center, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Xi Dong
- Reproductive Medicine Center, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China.
| | - Hongying Sha
- Reproductive Medicine Center, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai 200032, China.
| |
Collapse
|
8
|
Jokinen R, Marttinen P, Stewart JB, Neil Dear T, Battersby BJ. Tissue-specific modulation of mitochondrial DNA segregation by a defect in mitochondrial division. Hum Mol Genet 2015; 25:706-14. [PMID: 26681804 DOI: 10.1093/hmg/ddv508] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/08/2015] [Indexed: 01/19/2023] Open
Abstract
Mitochondria are dynamic organelles that divide and fuse by remodeling an outer and inner membrane in response to developmental, physiological and stress stimuli. These events are coordinated by conserved dynamin-related GTPases. The dynamics of mitochondrial morphology require coordination with mitochondrial DNA (mtDNA) to ensure faithful genome transmission, however, this process remains poorly understood. Mitochondrial division is linked to the segregation of mtDNA but how it affects cases of mtDNA heteroplasmy, where two or more mtDNA variants/mutations co-exist in a cell, is unknown. Segregation of heteroplasmic human pathogenic mtDNA mutations is a critical factor in the onset and severity of human mitochondrial diseases. Here, we investigated the coupling of mitochondrial morphology to the transmission and segregation of mtDNA in mammals by taking advantage of two genetically modified mouse models: one with a dominant-negative mutation in the dynamin-related protein 1 (Drp1 or Dnm1l) that impairs mitochondrial fission and the other, heteroplasmic mice segregating two neutral mtDNA haplotypes (BALB and NZB). We show a tissue-specific response to mtDNA segregation from a defect in mitochondrial fission. Only mtDNA segregation in the hematopoietic compartment is modulated from impaired Dnm1l function. In contrast, no effect was observed in other tissues arising from the three germ layers during development and in mtDNA transmission through the female germline. Our data suggest a robust organization of a heteroplasmic mtDNA segregating unit across mammalian cell types that can overcome impaired mitochondrial division to ensure faithful transmission of the mitochondrial genome.
Collapse
Affiliation(s)
- Riikka Jokinen
- Research Programs Unit - Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Paula Marttinen
- Research Programs Unit - Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - James B Stewart
- Max Planck Institute for Biology of Ageing, Cologne, Germany and
| | - T Neil Dear
- South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Brendan J Battersby
- Research Programs Unit - Molecular Neurology, University of Helsinki, Helsinki, Finland,
| |
Collapse
|
9
|
Stewart JB, Chinnery PF. The dynamics of mitochondrial DNA heteroplasmy: implications for human health and disease. Nat Rev Genet 2015; 16:530-42. [PMID: 26281784 DOI: 10.1038/nrg3966] [Citation(s) in RCA: 564] [Impact Index Per Article: 62.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Common genetic variants of mitochondrial DNA (mtDNA) increase the risk of developing several of the major health issues facing the western world, including neurodegenerative diseases. In this Review, we consider how these mtDNA variants arose and how they spread from their origin on one single molecule in a single cell to be present at high levels throughout a specific organ and, ultimately, to contribute to the population risk of common age-related disorders. mtDNA persists in all aerobic eukaryotes, despite a high substitution rate, clonal propagation and little evidence of recombination. Recent studies have found that de novo mtDNA mutations are suppressed in the female germ line; despite this, mtDNA heteroplasmy is remarkably common. The demonstration of a mammalian mtDNA genetic bottleneck explains how new germline variants can increase to high levels within a generation, and the ultimate fixation of less-severe mutations that escape germline selection explains how they can contribute to the risk of late-onset disorders.
Collapse
Affiliation(s)
- James B Stewart
- Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Patrick F Chinnery
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 1BZ, UK
| |
Collapse
|
10
|
Machado TS, Macabelli CH, Sangalli JR, Rodrigues TB, Smith LC, Meirelles FV, Chiaratti MR. Real-Time PCR Quantification of Heteroplasmy in a Mouse Model with Mitochondrial DNA of C57BL/6 and NZB/BINJ Strains. PLoS One 2015; 10:e0133650. [PMID: 26274500 PMCID: PMC4537288 DOI: 10.1371/journal.pone.0133650] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/30/2015] [Indexed: 11/18/2022] Open
Abstract
Mouse models are widely employed to study mitochondrial inheritance, which have implications to several human diseases caused by mutations in the mitochondrial genome (mtDNA). These mouse models take advantage of polymorphisms between the mtDNA of the NZB/BINJ and the mtDNA of common inbred laboratory (i.e., C57BL/6) strains to generate mice with two mtDNA haplotypes (heteroplasmy). Based on PCR followed by restriction fragment length polymorphism (PCR-RFLP), these studies determine the level of heteroplasmy across generations and in different cell types aiming to understand the mechanisms underlying mitochondrial inheritance. However, PCR-RFLP is a time-consuming method of low sensitivity and accuracy that dependents on the use of restriction enzyme digestions. A more robust method to measure heteroplasmy has been provided by the use of real-time quantitative PCR (qPCR) based on allelic refractory mutation detection system (ARMS-qPCR). Herein, we report an ARMS-qPCR assay for quantification of heteroplasmy using heteroplasmic mice with mtDNA of NZB/BINJ and C57BL/6 origin. Heteroplasmy and mtDNA copy number were estimated in germline and somatic tissues, providing evidence of the reliability of the approach. Furthermore, it enabled single-step quantification of heteroplasmy, with sensitivity to detect as low as 0.1% of either NZB/BINJ or C57BL/6 mtDNA. These findings are relevant as the ARMS-qPCR assay reported here is fully compatible with similar heteroplasmic mouse models used to study mitochondrial inheritance in mammals.
Collapse
Affiliation(s)
- Thiago Simões Machado
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, SP, 13565–905, Brazil
- Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, 05508–270, Brazil
- Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga, SP, 13635–900, Brazil
| | - Carolina Habermann Macabelli
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, SP, 13565–905, Brazil
- Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga, SP, 13635–900, Brazil
| | - Juliano Rodrigues Sangalli
- Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, 05508–270, Brazil
- Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga, SP, 13635–900, Brazil
| | - Thiago Bittencourt Rodrigues
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, SP, 13565–905, Brazil
| | - Lawrence Charles Smith
- Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, 05508–270, Brazil
- Centre de recherche en reproduction animale, Faculté de Medecine Vétérinaire, Université de Montréal, Saint Hyacinthe, QC, J2S 7C6, Canada
| | - Flávio Vieira Meirelles
- Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, 05508–270, Brazil
- Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga, SP, 13635–900, Brazil
| | - Marcos Roberto Chiaratti
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, SP, 13565–905, Brazil
- Departamento de Cirurgia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, 05508–270, Brazil
- Departamento de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga, SP, 13635–900, Brazil
- * E-mail:
| |
Collapse
|
11
|
Quantitative changes in Gimap3 and Gimap5 expression modify mitochondrial DNA segregation in mice. Genetics 2015; 200:221-35. [PMID: 25808953 DOI: 10.1534/genetics.115.175596] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 03/20/2015] [Indexed: 01/22/2023] Open
Abstract
Mammalian mitochondrial DNA (mtDNA) is a high-copy maternally inherited genome essential for aerobic energy metabolism. Mutations in mtDNA can lead to heteroplasmy, the co-occurence of two different mtDNA variants in the same cell, which can segregate in a tissue-specific manner affecting the onset and severity of mitochondrial dysfunction. To investigate mechanisms regulating mtDNA segregation we use a heteroplasmic mouse model with two polymorphic neutral mtDNA haplotypes (NZB and BALB) that displays tissue-specific and age-dependent selection for mtDNA haplotypes. In the hematopoietic compartment there is selection for the BALB mtDNA haplotype, a phenotype that can be modified by allelic variants of Gimap3. Gimap3 is a tail-anchored member of the GTPase of the immunity-associated protein (Gimap) family of protein scaffolds important for leukocyte development and survival. Here we show how the expression of two murine Gimap3 alleles from Mus musculus domesticus and M. m. castaneus differentially affect mtDNA segregation. The castaneus allele has incorporated a uORF (upstream open reading frame) in-frame with the Gimap3 mRNA that impairs translation and imparts a negative effect on the steady-state protein abundance. We found that quantitative changes in the expression of Gimap3 and the paralogue Gimap5, which encodes a lysosomal protein, affect mtDNA segregation in the mouse hematopoietic tissues. We also show that Gimap3 localizes to the endoplasmic reticulum and not mitochondria as previously reported. Collectively these data show that the abundance of protein scaffolds on the endoplasmic reticulum and lysosomes are important to the segregation of the mitochondrial genome in the mouse hematopoietic compartment.
Collapse
|
12
|
Jokinen R, Junnila H, Battersby BJ. Gimap3: A foot-in-the-door to tissue-specific regulation of mitochondrial DNA genetics. Small GTPases 2014; 2:31-35. [PMID: 21686279 DOI: 10.4161/sgtp.2.1.14937] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 01/18/2011] [Accepted: 01/23/2011] [Indexed: 01/31/2023] Open
Abstract
Mitochondrial DNA (mtDNA) is a multi-copy genome encoding for proteins essential for aerobic energy metabolism. Mutations in mtDNA can lead to a variety of human diseases, from mild metabolic syndromes to severe fatal encephalomyopathies. Most mtDNA mutations co-exist with wild type genomes in a state known as heteroplasmy. The segregation of these pathogenic mutants is tissue and mutation specific, and a key determinant in the onset and severity of human mitochondrial disorders. We used a forward genetic approach in mice to identify and demonstrate that Gimap3 (GTP ase of immunity associated protein) is a key regulator of mtDNA segregation in leukocytes. The Gimap gene cluster is found only in vertebrates and appear to be a class of nucleotide-dependent dimerization GTP ases. Gimap3 is a membrane-anchored GTP ase with a critical role in T cell development. Here, we summarize our genetic findings and postulate how Gimap3 might regulate mtDNA genetics.
Collapse
Affiliation(s)
- Riikka Jokinen
- Research Program of Molecular Neurology and Institute of Biomedicine; Biomedicum Helsinki; University of Helsinki; Helsinki, Finland
| | | | | |
Collapse
|
13
|
An exploratory analysis of mitochondrial haplotypes and allogeneic hematopoietic cell transplantation outcomes. Biol Blood Marrow Transplant 2014; 21:81-8. [PMID: 25300867 DOI: 10.1016/j.bbmt.2014.09.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/24/2014] [Indexed: 12/13/2022]
Abstract
Certain mitochondrial haplotypes (mthaps) are associated with disease, possibly through differences in oxidative phosphorylation and/or immunosurveillance. We explored whether mthaps are associated with allogeneic hematopoietic cell transplantation (HCT) outcomes. Recipient (n = 437) and donor (n = 327) DNA were genotyped for common European mthaps (H, J, U, T, Z, K, V, X, I, W, and K2). HCT outcomes for mthap matched siblings (n = 198), all recipients, and all donors were modeled using relative risks (RR) and 95% confidence intervals and compared with mthap H, the most common mitochondrial haplotypes. Siblings with I and V were significantly more likely to die within 5 years (RR = 3.0; 95% confidence interval [CI], 1.2 to 7.9; and RR = 4.6; 95% CI, 1.8 to 12.3, respectively). W siblings experienced higher acute graft-versus-host disease (GVHD) grades II to IV events (RR = 2.1; 95% CI, 1.1 to 2.4) with no events for those with K or K2. Similar results were observed for all recipients combined, although J recipients experienced lower GVHD and higher relapse. Patients with I donors had a 2.7-fold (1.2 to 6.2) increased risk of death in 5 years, whereas few patients with K2 or W donors died. No patients with K2 donors and few patients with U donors relapsed. Mthap may be an important consideration in HCT outcomes, although validation and functional studies are needed. If confirmed, it may be feasible to select donors based on mthap to increase positive or decrease negative outcomes.
Collapse
|
14
|
Siciliano G, Pasquali L, Mancuso M, Murri L. Molecular diagnostics and mitochondrial dysfunction: a future perspective. Expert Rev Mol Diagn 2014; 8:531-49. [DOI: 10.1586/14737159.8.4.531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
15
|
Wallace DC, Chalkia D. Mitochondrial DNA genetics and the heteroplasmy conundrum in evolution and disease. Cold Spring Harb Perspect Biol 2013; 5:a021220. [PMID: 24186072 PMCID: PMC3809581 DOI: 10.1101/cshperspect.a021220] [Citation(s) in RCA: 441] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The unorthodox genetics of the mtDNA is providing new perspectives on the etiology of the common "complex" diseases. The maternally inherited mtDNA codes for essential energy genes, is present in thousands of copies per cell, and has a very high mutation rate. New mtDNA mutations arise among thousands of other mtDNAs. The mechanisms by which these "heteroplasmic" mtDNA mutations come to predominate in the female germline and somatic tissues is poorly understood, but essential for understanding the clinical variability of a range of diseases. Maternal inheritance and heteroplasmy also pose major challengers for the diagnosis and prevention of mtDNA disease.
Collapse
Affiliation(s)
- Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | | |
Collapse
|
16
|
Abstract
Mitochondrial DNA (mtDNA) is essential for aerobic energy production in eukaryotic cells, and mutations in this genome can lead to mitochondrial dysfunction. Human mtDNA mutations are typically heteroplasmic, a mix of mutant and wild-type genomes, which can present as a heterogeneous group of disorders ranging in severity from mild to fatal, and commonly affecting highly aerobic tissues such as heart, skeletal muscle, and neurons. During the 1990s, many research groups started to notice that mtDNA mutations could segregate depending upon the mutation and tissue. This segregation pattern can have a direct effect on the onset and severity of these mutations. However, these segregation patterns could not be easily explained by respiratory chain function, implying that there is regulation of mtDNA independent of its bioenergetic role. A lot of research on this topic has been largely descriptive, but over the last several years advances in mitochondrial biology have provided some mechanistic insight into the regulation of the organelle and its genome. This review addresses these advances with respect to somatic segregation of mtDNA in mammals.
Collapse
Affiliation(s)
- Riikka Jokinen
- Research Programs Unit-Molecular Neurology, and Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | | |
Collapse
|
17
|
Sharpley MS, Marciniak C, Eckel-Mahan K, McManus M, Crimi M, Waymire K, Lin CS, Masubuchi S, Friend N, Koike M, Chalkia D, MacGregor G, Sassone-Corsi P, Wallace DC. Heteroplasmy of mouse mtDNA is genetically unstable and results in altered behavior and cognition. Cell 2012; 151:333-343. [PMID: 23063123 DOI: 10.1016/j.cell.2012.09.004] [Citation(s) in RCA: 256] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 06/08/2012] [Accepted: 08/20/2012] [Indexed: 12/24/2022]
Abstract
Maternal inheritance of mtDNA is the rule in most animals, but the reasons for this pattern remain unclear. To investigate the consequence of overriding uniparental inheritance, we generated mice containing an admixture (heteroplasmy) of NZB and 129S6 mtDNAs in the presence of a congenic C57BL/6J nuclear background. Analysis of the segregation of the two mtDNAs across subsequent maternal generations revealed that proportion of NZB mtDNA was preferentially reduced. Ultimately, this segregation process produced NZB-129 heteroplasmic mice and their NZB or 129 mtDNA homoplasmic counterparts. Phenotypic comparison of these three mtDNA lines demonstrated that the NZB-129 heteroplasmic mice, but neither homoplasmic counterpart, had reduced activity, food intake, respiratory exchange ratio; accentuated stress response; and cognitive impairment. Therefore, admixture of two normal but different mouse mtDNAs can be genetically unstable and can produce adverse physiological effects, factors that may explain the advantage of uniparental inheritance of mtDNA.
Collapse
Affiliation(s)
- Mark S Sharpley
- Center for Mitochondrial and Epigenomic Medicine, the Children's Hospital of Philadelphia and the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Colket Translational Research Building, Philadelphia, PA 19104-4302, USA.,Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Christine Marciniak
- Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Kristin Eckel-Mahan
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA.,Center for Epigenetics and Metabolism, University of California, Irvine, Irvine, CA 92697, USA
| | - Meagan McManus
- Center for Mitochondrial and Epigenomic Medicine, the Children's Hospital of Philadelphia and the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Colket Translational Research Building, Philadelphia, PA 19104-4302, USA
| | - Marco Crimi
- Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Katrina Waymire
- Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA.,Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Chun Shi Lin
- Center for Mitochondrial and Epigenomic Medicine, the Children's Hospital of Philadelphia and the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Colket Translational Research Building, Philadelphia, PA 19104-4302, USA.,Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Satoru Masubuchi
- Center for Epigenetics and Metabolism, University of California, Irvine, Irvine, CA 92697, USA
| | - Nicole Friend
- Center for Mitochondrial and Epigenomic Medicine, the Children's Hospital of Philadelphia and the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Colket Translational Research Building, Philadelphia, PA 19104-4302, USA.,Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Maya Koike
- Center for Mitochondrial and Epigenomic Medicine, the Children's Hospital of Philadelphia and the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Colket Translational Research Building, Philadelphia, PA 19104-4302, USA
| | - Dimitra Chalkia
- Center for Mitochondrial and Epigenomic Medicine, the Children's Hospital of Philadelphia and the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Colket Translational Research Building, Philadelphia, PA 19104-4302, USA.,Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Grant MacGregor
- Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Paolo Sassone-Corsi
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA.,Center for Epigenetics and Metabolism, University of California, Irvine, Irvine, CA 92697, USA
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, the Children's Hospital of Philadelphia and the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Colket Translational Research Building, Philadelphia, PA 19104-4302, USA.,Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, Irvine, CA 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| |
Collapse
|
18
|
Abstract
Mitochondria perform diverse yet interconnected functions, producing ATP and many biosynthetic intermediates while also contributing to cellular stress responses such as autophagy and apoptosis. Mitochondria form a dynamic, interconnected network that is intimately integrated with other cellular compartments. In addition, mitochondrial functions extend beyond the boundaries of the cell and influence an organism's physiology by regulating communication between cells and tissues. It is therefore not surprising that mitochondrial dysfunction has emerged as a key factor in a myriad of diseases, including neurodegenerative and metabolic disorders. We provide a current view of how mitochondrial functions impinge on health and disease.
Collapse
Affiliation(s)
- Jodi Nunnari
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA.
| | | |
Collapse
|
19
|
Jokinen R, Marttinen P, Sandell HK, Manninen T, Teerenhovi H, Wai T, Teoli D, Loredo-Osti JC, Shoubridge EA, Battersby BJ. Gimap3 regulates tissue-specific mitochondrial DNA segregation. PLoS Genet 2010; 6:e1001161. [PMID: 20976251 PMCID: PMC2954831 DOI: 10.1371/journal.pgen.1001161] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 09/15/2010] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial DNA (mtDNA) sequence variants segregate in mutation and tissue-specific manners, but the mechanisms remain unknown. The segregation pattern of pathogenic mtDNA mutations is a major determinant of the onset and severity of disease. Using a heteroplasmic mouse model, we demonstrate that Gimap3, an outer mitochondrial membrane GTPase, is a critical regulator of this process in leukocytes. Gimap3 is important for T cell development and survival, suggesting that leukocyte survival may be a key factor in the genetic regulation of mtDNA sequence variants and in modulating human mitochondrial diseases.
Collapse
Affiliation(s)
- Riikka Jokinen
- Research Program of Molecular Neurology and Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Paula Marttinen
- Research Program of Molecular Neurology and Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Helen Katarin Sandell
- Research Program of Molecular Neurology and Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Tuula Manninen
- Research Program of Molecular Neurology and Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Heli Teerenhovi
- Research Program of Molecular Neurology and Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Timothy Wai
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Daniella Teoli
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - J. C. Loredo-Osti
- Department of Mathematics and Statistics, Memorial University, St. John's, Newfoundland, Canada
| | - Eric A. Shoubridge
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Brendan J. Battersby
- Research Program of Molecular Neurology and Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
- * E-mail:
| |
Collapse
|
20
|
Mitochondrial DNA mutations and human disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:113-28. [PMID: 19761752 DOI: 10.1016/j.bbabio.2009.09.005] [Citation(s) in RCA: 417] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/04/2009] [Accepted: 09/09/2009] [Indexed: 01/07/2023]
Abstract
Mitochondrial disorders are a group of clinically heterogeneous diseases, commonly defined by a lack of cellular energy due to oxidative phosphorylation (OXPHOS) defects. Since the identification of the first human pathological mitochondrial DNA (mtDNA) mutations in 1988, significant efforts have been spent in cataloguing the vast array of causative genetic defects of these disorders. Currently, more than 250 pathogenic mtDNA mutations have been identified. An ever-increasing number of nuclear DNA mutations are also being reported as the majority of proteins involved in mitochondrial metabolism and maintenance are nuclear-encoded. Understanding the phenotypic diversity and elucidating the molecular mechanisms at the basis of these diseases has however proved challenging. Progress has been hampered by the peculiar features of mitochondrial genetics, an inability to manipulate the mitochondrial genome, and difficulties in obtaining suitable models of disease. In this review, we will first outline the unique features of mitochondrial genetics before detailing the diseases and their genetic causes, focusing specifically on primary mtDNA genetic defects. The functional consequences of mtDNA mutations that have been characterised to date will also be discussed, along with current and potential future diagnostic and therapeutic advances.
Collapse
|
21
|
Mouse models of mitochondrial DNA defects and their relevance for human disease. EMBO Rep 2009; 10:137-43. [PMID: 19148224 DOI: 10.1038/embor.2008.242] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Accepted: 11/28/2008] [Indexed: 01/08/2023] Open
Abstract
Qualitative and quantitative changes in mitochondrial DNA (mtDNA) have been shown to be common causes of inherited neurodegenerative and muscular diseases, and have also been implicated in ageing. These diseases can be caused by primary mtDNA mutations, or by defects in nuclear-encoded mtDNA maintenance proteins that cause secondary mtDNA mutagenesis or instability. Furthermore, it has been proposed that mtDNA copy number affects cellular tolerance to environmental stress. However, the mechanisms that regulate mtDNA copy number and the tissue-specific consequences of mtDNA mutations are largely unknown. As post-mitotic tissues differ greatly from proliferating cultured cells in their need for mtDNA maintenance, and as most mitochondrial diseases affect post-mitotic cell types, the mouse is an important model in which to study mtDNA defects. Here, we review recently developed mouse models, and their contribution to our knowledge of mtDNA maintenance and its role in disease.
Collapse
|
22
|
Wai T, Teoli D, Shoubridge EA. The mitochondrial DNA genetic bottleneck results from replication of a subpopulation of genomes. Nat Genet 2008; 40:1484-8. [PMID: 19029901 DOI: 10.1038/ng.258] [Citation(s) in RCA: 325] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 09/19/2008] [Indexed: 11/09/2022]
Abstract
In mammals, mitochondrial DNA (mtDNA) sequence variants are observed to segregate rapidly between generations despite the high mtDNA copy number in the oocyte. This has led to the concept of a genetic bottleneck for the transmission of mtDNA, but the mechanism remains contentious. Several studies have suggested that the bottleneck occurs during embryonic development, as a result of a marked reduction in germline mtDNA copy number. Mitotic segregation of mtDNAs during preimplantation, or during the expansion of primordial germ cells (PGCs) before they colonize the gonad, is thought to account for the increase in genotypic variance observed among mature oocytes from heteroplasmic mothers. This view has, however, been challenged by studies suggesting that the bottleneck occurs without a reduction in germline mtDNA content. To resolve this controversy, we measured mtDNA heteroplasmy and copy number in single germ cells isolated from heteroplasmic mice. By directly tracking the evolution of mtDNA genotypic variance during oogenesis, we show that the genetic bottleneck occurs during postnatal folliculogenesis and not during embryonic oogenesis.
Collapse
Affiliation(s)
- Timothy Wai
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, Canada
| | | | | |
Collapse
|
23
|
MtDNA mutation associated with mitochondrial dysfunction in megakaryoblastic leukaemic cells. Leukemia 2008; 22:1938-41. [DOI: 10.1038/leu.2008.69] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
24
|
Rajasimha HK, Chinnery PF, Samuels DC. Selection against pathogenic mtDNA mutations in a stem cell population leads to the loss of the 3243A-->G mutation in blood. Am J Hum Genet 2008; 82:333-43. [PMID: 18252214 PMCID: PMC2427290 DOI: 10.1016/j.ajhg.2007.10.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 09/18/2007] [Accepted: 10/03/2007] [Indexed: 12/30/2022] Open
Abstract
The mutation 3243A-->G is the most common heteroplasmic pathogenic mitochondrial DNA (mtDNA) mutation in humans, but it is not understood why the proportion of this mutation decreases in blood during life. Changing levels of mtDNA heteroplasmy are fundamentally related to the pathophysiology of the mitochondrial disease and correlate with clinical progression. To understand this process, we simulated the segregation of mtDNA in hematopoietic stem cells and leukocyte precursors. Our observations show that the percentage of mutant mtDNA in blood decreases exponentially over time. This is consistent with the existence of a selective process acting at the stem cell level and explains why the level of mutant mtDNA in blood is almost invariably lower than in nondividing (postmitotic) tissues such as skeletal muscle. By using this approach, we derived a formula from human data to correct for the change in heteroplasmy over time. A comparison of age-corrected blood heteroplasmy levels with skeletal muscle, an embryologically distinct postmitotic tissue, provides independent confirmation of the model. These findings indicate that selection against pathogenic mtDNA mutations occurs in a stem cell population.
Collapse
Affiliation(s)
- Harsha Karur Rajasimha
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 USA
| | - Patrick F. Chinnery
- Mitochondrial Research Group and Institute of Human Genetics, Newcastle University, The Medical School, Newcastle-upon-Tyne NE2 4HH, UK
| | - David C. Samuels
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 USA
| |
Collapse
|
25
|
Battersby BJ, Shoubridge EA. Reactive oxygen species and the segregation of mtDNA sequence variants. Nat Genet 2008; 39:571-2; author reply 572. [PMID: 17460678 DOI: 10.1038/ng0507-571] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
26
|
Wyrobek AJ, Mulvihill JJ, Wassom JS, Malling HV, Shelby MD, Lewis SE, Witt KL, Preston RJ, Perreault SD, Allen JW, DeMarini DM, Woychik RP, Bishop JB. Assessing human germ-cell mutagenesis in the Postgenome Era: a celebration of the legacy of William Lawson (Bill) Russell. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2007; 48:71-95. [PMID: 17295306 PMCID: PMC2071946 DOI: 10.1002/em.20284] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Birth defects, de novo genetic diseases, and chromosomal abnormality syndromes occur in approximately 5% of all live births, and affected children suffer from a broad range of lifelong health consequences. Despite the social and medical impact of these defects, and the 8 decades of research in animal systems that have identified numerous germ-cell mutagens, no human germ-cell mutagen has been confirmed to date. There is now a growing consensus that the inability to detect human germ-cell mutagens is due to technological limitations in the detection of random mutations rather than biological differences between animal and human susceptibility. A multidisciplinary workshop responding to this challenge convened at The Jackson Laboratory in Bar Harbor, Maine. The purpose of the workshop was to assess the applicability of an emerging repertoire of genomic technologies to studies of human germ-cell mutagenesis. Workshop participants recommended large-scale human germ-cell mutation studies be conducted using samples from donors with high-dose exposures, such as cancer survivors. Within this high-risk cohort, parents and children could be evaluated for heritable changes in (a) DNA sequence and chromosomal structure, (b) repeat sequences and minisatellites, and (c) global gene expression profiles and pathways. Participants also advocated the establishment of a bio-bank of human tissue samples from donors with well-characterized exposure, including medical and reproductive histories. This mutational resource could support large-scale, multiple-endpoint studies. Additional studies could involve the examination of transgenerational effects associated with changes in imprinting and methylation patterns, nucleotide repeats, and mitochondrial DNA mutations. The further development of animal models and the integration of these with human studies are necessary to provide molecular insights into the mechanisms of germ-cell mutations and to identify prevention strategies. Furthermore, scientific specialty groups should be convened to review and prioritize the evidence for germ-cell mutagenicity from common environmental, occupational, medical, and lifestyle exposures. Workshop attendees agreed on the need for a full-scale assault to address key fundamental questions in human germ-cell environmental mutagenesis. These include, but are not limited to, the following: Do human germ-cell mutagens exist? What are the risks to future generations? Are some parents at higher risk than others for acquiring and transmitting germ-cell mutations? Obtaining answers to these, and other critical questions, will require strong support from relevant funding agencies, in addition to the engagement of scientists outside the fields of genomics and germ-cell mutagenesis.
Collapse
Affiliation(s)
| | - John J. Mulvihill
- University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - John S. Wassom
- YAHSGS, LLC, Richland, Washington
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Heinrich V. Malling
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Michael D. Shelby
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | | | - Kristine L. Witt
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - R. Julian Preston
- US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Sally D. Perreault
- US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - James W. Allen
- US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - David M. DeMarini
- US Environmental Protection Agency, Research Triangle Park, North Carolina
| | | | - Jack B. Bishop
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
- *Correspondence to: Dr. Jack B. Bishop, National Institute of Environmental Health Sciences, EC-01, PO Box 12233, Research Triangle Park, North Carolina, USA. E-mail:
| | | |
Collapse
|
27
|
Pyle A, Taylor RW, Durham SE, Deschauer M, Schaefer AM, Samuels DC, Chinnery PF. Depletion of mitochondrial DNA in leucocytes harbouring the 3243A->G mtDNA mutation. J Med Genet 2006; 44:69-74. [PMID: 16950816 PMCID: PMC2597915 DOI: 10.1136/jmg.2006.043109] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND The 3243A-->G MTTL1 mutation is the most common heteroplasmic mitochondrial DNA (mtDNA) mutation associated with disease. Previous studies have shown that the percentage of mutated mtDNA decreases in blood as patients get older, but the mechanisms behind this remain unclear. OBJECTIVES AND METHOD To understand the dynamics of the process and the underlying mechanisms, an accurate fluorescent assay was established for 3243A-->G heteroplasmy and the amount of mtDNA in blood with real-time polymerase chain reaction was determined. The amount of mutated and wild-type mtDNA was measured at two time points in 11 subjects. RESULTS The percentage of mutated mtDNA decreases exponentially during life, and peripheral blood leucocytes in patients harbouring 3243A-->G are profoundly depleted of mtDNA. CONCLUSIONS A similar decrease in mtDNA has been seen in other mitochondrial disorders, and in 3243A-->G cell lines in culture, indicating that depletion of mtDNA may be a common secondary phenomenon in several mitochondrial diseases. Depletion of mtDNA is not always due to mutation of a nuclear gene involved in mtDNA maintenance.
Collapse
|
28
|
Malka F, Lombès A, Rojo M. Organization, dynamics and transmission of mitochondrial DNA: focus on vertebrate nucleoids. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:463-72. [PMID: 16730385 DOI: 10.1016/j.bbamcr.2006.04.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 04/04/2006] [Accepted: 04/04/2006] [Indexed: 11/21/2022]
Abstract
Eukaryotic cells contain numerous copies of the mitochondrial genome (from 50 to 100 copies in the budding yeast to some thousands in humans) that localize to numerous intramitochondrial nucleoprotein complexes called nucleoids. The transmission of mitochondrial DNA differs significantly from that of nuclear genomes and depends on the number, molecular composition and dynamic properties of nucleoids and on the organization and dynamics of the mitochondrial compartment. While the localization, dynamics and protein composition of mitochondrial DNA nucleoids begin to be described, we are far from knowing all mechanisms and molecules mediating and/or regulating these processes. Here, we review our current knowledge on vertebrate nucleoids and discuss similarities and differences to nucleoids of other eukaryots.
Collapse
Affiliation(s)
- Florence Malka
- INSERM U582, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Université Pierre et Marie Curie, IFR14, 47, boulevard de l'Hôpital, 75651 Paris cedex 13, France
| | | | | |
Collapse
|