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Volpe KE, Samuels DC, Elson JL, Steyn JS, Gebretsadik T, Ellis RJ, Heaton RK, Kallianpur AR, Letendre S, Hulgan T. Mitochondrial DNA mutation pathogenicity score and neurocognitive performance in persons with HIV. Mitochondrion 2024; 74:101820. [PMID: 37989461 PMCID: PMC10872545 DOI: 10.1016/j.mito.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 10/06/2023] [Accepted: 11/03/2023] [Indexed: 11/23/2023]
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) genetic variation is associated with neurocognitive (NC) impairment (NCI) in people with HIV (PWH). Other approaches use sequence conservation and protein structure to predict the impact of mtDNA variants on protein function. We examined predicted mtDNA variant pathogenicity in the CHARTER study using MutPred scores, hypothesizing that persons with higher scores (greater predicted pathogenicity) have more NCI. METHODS CHARTER included NC testing in PWH from 2003 to 2007. MutPred scores were assigned to CHARTER participants with mtDNA sequence; any score > 0.5 was considered potentially deleterious. Outcomes at cohort entry were NCI, defined by global and seven NC domain deficit scores, and by mean global and domain NC performance T-scores. Univariate and multivariable regression analyses assessed associations between having a deleterious variant and NCI. Additional models included estimated peripheral blood cell mtDNA copy number. RESULTS Data were available for 744 PWH (357 African ancestry; 317 European; 70 Hispanic). In the overall cohort, PWH having any potentially deleterious variant were less likely to have motor impairment (16 vs. 25 %, p = 0.001). In multivariable analysis, having a deleterious variant remained associated with lower likelihood of motor impairment (adjusted odds ratio 0.59 [95 % CI 0.41-0.88]; p = 0.009), and better motor performance by T-score (β 1.71 [0.31-3.10], p = 0.02). Associations persisted after adjustment for estimated mtDNA quantity. CONCLUSIONS In these PWH, having a potentially deleterious mtDNA variant was associated with less motor impairment. These unexpected findings suggest that potentially deleterious mtDNA variations may confer protection against impaired motor function by as yet unknown mechanisms.
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Affiliation(s)
- Karen E Volpe
- Vanderbilt University Medical Center, Nashville, TN, USA
| | - David C Samuels
- Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Joanna L Elson
- Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Jannetta S Steyn
- Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | | | | | | | | | | | - Todd Hulgan
- Vanderbilt University Medical Center, Nashville, TN, USA.
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2
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Ehrmann I, Crichton JH, Gazzara MR, James K, Liu Y, Grellscheid SN, Curk T, de Rooij D, Steyn JS, Cockell S, Adams IR, Barash Y, Elliott DJ. An ancient germ cell-specific RNA-binding protein protects the germline from cryptic splice site poisoning. eLife 2019; 8:39304. [PMID: 30674417 PMCID: PMC6345566 DOI: 10.7554/elife.39304] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 12/18/2018] [Indexed: 12/28/2022] Open
Abstract
Male germ cells of all placental mammals express an ancient nuclear RNA binding protein of unknown function called RBMXL2. Here we find that deletion of the retrogene encoding RBMXL2 blocks spermatogenesis. Transcriptome analyses of age-matched deletion mice show that RBMXL2 controls splicing patterns during meiosis. In particular, RBMXL2 represses the selection of aberrant splice sites and the insertion of cryptic and premature terminal exons. Our data suggest a Rbmxl2 retrogene has been conserved across mammals as part of a splicing control mechanism that is fundamentally important to germ cell biology. We propose that this mechanism is essential to meiosis because it buffers the high ambient concentrations of splicing activators, thereby preventing poisoning of key transcripts and disruption to gene expression by aberrant splice site selection. In humans and other mammals, a sperm from a male fuses with an egg cell from a female to produce an embryo that may ultimately grow into a new individual. Sperm and egg cells are made when certain cells in the body divide in a process called meiosis. Many proteins are required for meiosis to happen and these proteins are made using instructions provided by genes, which are made of a molecule called DNA. The DNA within a gene is transcribed to make molecules of ribonucleic acid (or RNA for short). The cell then modifies many of these RNAs in a process called splicing before using them as templates to make proteins. During splicing, segments of RNA known as introns are discarded and other segments termed exons are joined together. Some exons may also be removed from RNAs in different combinations to create different proteins from the same gene. A protein called RBMXL2 is able to bind to RNA molecules and is only made during and after meiosis in humans and most other mammals. RBMXL2 can also bind to other proteins that are known to be involved in controlling splicing of RNAs, but its role in splicing remains unclear. To address this question, Ehrmann et al. studied the gene that encodes the RBMXL2 protein in mice. Removing this gene prevented male mice from being able to make sperm. Further experiments using a technique called RNA sequencing showed that the RBMXL2 protein helps to ensure that splicing happens correctly by preventing bits of exons and introns in mouse genes from being rearranged. These findings suggest that the gene encoding RBMXL2 is part of a splicing control mechanism that is important for making sperm and egg cells. The work of Ehrmann et al. could eventually help some couples understand why they have problems conceiving children. Male infertility is poorly understood, and not knowing its causes can harm the mental health of affected men. Furthermore, these findings may help researchers to understand the role of a closely related protein called RBMY that has also been linked to infertility in men, but is much more difficult to study.
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Affiliation(s)
- Ingrid Ehrmann
- Institute of Genetic Medicine, Newcastle University, Newcastle, United Kingdom
| | - James H Crichton
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew R Gazzara
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States.,Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Katherine James
- Life Sciences, Natural History Museum, London, United Kingdom
| | - Yilei Liu
- Institute of Genetic Medicine, Newcastle University, Newcastle, United Kingdom.,Department of Plant and Microbial Biology, University of Zürich, Zürich, Switzerland
| | - Sushma Nagaraja Grellscheid
- Institute of Genetic Medicine, Newcastle University, Newcastle, United Kingdom.,School of Biological and Biomedical Sciences, University of Durham, Durham, United Kingdom
| | - Tomaž Curk
- Laboratory of Bioinformatics, Faculty of Computer and Information Sciences, University of Ljubljana, Ljubljana, Slovenia
| | - Dirk de Rooij
- Reproductive Biology Group, Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.,Center for Reproductive Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jannetta S Steyn
- Bioinformatics Support Unit, Faculty of Medical Sciences, Newcastle University, Newcastle, United Kingdom
| | - Simon Cockell
- Bioinformatics Support Unit, Faculty of Medical Sciences, Newcastle University, Newcastle, United Kingdom
| | - Ian R Adams
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Yoseph Barash
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States.,Department of Computer and Information Science, University of Pennsylvania, Philadelphia, United States
| | - David J Elliott
- Institute of Genetic Medicine, Newcastle University, Newcastle, United Kingdom
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Mellough CB, Bauer R, Collin J, Dorgau B, Zerti D, Dolan DWP, Jones CM, Izuogu OG, Yu M, Hallam D, Steyn JS, White K, Steel DH, Santibanez-Koref M, Elliott DJ, Jackson MS, Lindsay S, Grellscheid S, Lako M. An integrated transcriptional analysis of the developing human retina. Development 2019; 146:146/2/dev169474. [PMID: 30696714 PMCID: PMC6361134 DOI: 10.1242/dev.169474] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/24/2018] [Indexed: 12/11/2022]
Abstract
The scarcity of embryonic/foetal material as a resource for direct study means that there is still limited understanding of human retina development. Here, we present an integrated transcriptome analysis combined with immunohistochemistry in human eye and retinal samples from 4 to 19 post-conception weeks. This analysis reveals three developmental windows with specific gene expression patterns that informed the sequential emergence of retinal cell types and enabled identification of stage-specific cellular and biological processes, and transcriptional regulators. Each stage is characterised by a specific set of alternatively spliced transcripts that code for proteins involved in the formation of the photoreceptor connecting cilium, pre-mRNA splicing and epigenetic modifiers. Importantly, our data show that the transition from foetal to adult retina is characterised by a large increase in the percentage of mutually exclusive exons that code for proteins involved in photoreceptor maintenance. The circular RNA population is also defined and shown to increase during retinal development. Collectively, these data increase our understanding of human retinal development and the pre-mRNA splicing process, and help to identify new candidate disease genes.
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Affiliation(s)
- Carla B. Mellough
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK,Lions Eye Institute, 2 Verdun Street, Nedlands, Perth, WA 6009, Australia
| | - Roman Bauer
- School of Computing, Newcastle University, Newcastle NE4 5TG, UK
| | - Joseph Collin
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Birthe Dorgau
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Darin Zerti
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - David W. P. Dolan
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Carl M. Jones
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Osagie G. Izuogu
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK,European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge CB10 1SD, UK
| | - Min Yu
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Dean Hallam
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Jannetta S. Steyn
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Kathryn White
- EM Research Services, Newcastle University, Newcastle NE2 4HH, UK
| | - David H. Steel
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | | | - David J. Elliott
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Michael S. Jackson
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Susan Lindsay
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
| | - Sushma Grellscheid
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, Newcastle NE1 3BZ, UK
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Queen RA, Steyn JS, Lord P, Elson JL. Mitochondrial DNA sequence context in the penetrance of mitochondrial t-RNA mutations: A study across multiple lineages with diagnostic implications. PLoS One 2017; 12:e0187862. [PMID: 29161289 PMCID: PMC5697862 DOI: 10.1371/journal.pone.0187862] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 10/28/2017] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial DNA (mtDNA) mutations are well recognized as an important cause of inherited disease. Diseases caused by mtDNA mutations exhibit a high degree of clinical heterogeneity with a complex genotype-phenotype relationship, with many such mutations exhibiting incomplete penetrance. There is evidence that the spectrum of mutations causing mitochondrial disease might differ between different mitochondrial lineages (haplogroups) seen in different global populations. This would point to the importance of sequence context in the expression of mutations. To explore this possibility, we looked for mutations which are known to cause disease in humans, in animals of other species unaffected by mtDNA disease. The mt-tRNA genes are the location of many pathogenic mutations, with the m.3243A>G mutation on the mt-tRNA-Leu(UUR) being the most frequently seen mutation in humans. This study looked for the presence of m.3243A>G in 2784 sequences from 33 species, as well as any of the other mutations reported in association with disease located on mt-tRNA-Leu(UUR). We report a number of disease associated variations found on mt-tRNA-Leu(UUR) in other chordates, as the major population variant, with m.3243A>G being seen in 6 species. In these, we also found a number of mutations which appear compensatory and which could prevent the pathogenicity associated with this change in humans. This work has important implications for the discovery and diagnosis of mtDNA mutations in non-European populations. In addition, it might provide a partial explanation for the conflicting results in the literature that examines the role of mtDNA variants in complex traits.
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Affiliation(s)
- Rachel A. Queen
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Jannetta S. Steyn
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Phillip Lord
- School of Computing Science, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Joanna L. Elson
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- Centre for Human Metabonomics, North-West University, Potchefstroom, South Africa
- * E-mail:
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Widdrington JD, Gomez-Duran A, Steyn JS, Pyle A, Ruchaud-Sparagano MH, Scott J, Baudouin SV, Rostron AJ, Simpson J, Chinnery PF. Mitochondrial DNA depletion induces innate immune dysfunction rescued by IFN-γ. J Allergy Clin Immunol 2017. [PMID: 28629747 PMCID: PMC5667580 DOI: 10.1016/j.jaci.2017.04.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- John D Widdrington
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Aurora Gomez-Duran
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Jannetta S Steyn
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Bioinformatics Support Unit, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Angela Pyle
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - Jonathan Scott
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Simon V Baudouin
- Department of Anaesthesia, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Anthony J Rostron
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - John Simpson
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Patrick F Chinnery
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, United Kingdom; Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.
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Steyn JS, Andras P. Analysis of the dynamics of temporal relationships of neural activities using optical imaging data. J Comput Neurosci 2016; 42:107-121. [PMID: 27778248 PMCID: PMC5350244 DOI: 10.1007/s10827-016-0630-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 08/23/2016] [Accepted: 10/03/2016] [Indexed: 11/26/2022]
Abstract
The temporal relationship between the activities of neurons in biological neural systems is critically important for the correct delivery of the functionality of these systems. Fine measurement of temporal relationships of neural activities using micro-electrodes is possible but this approach is very limited due to spatial constraints in the context of physiologically valid settings of neural systems. Optical imaging with voltage-sensitive dyes or calcium dyes can provide data about the activity patterns of many neurons in physiologically valid settings, but the data is relatively noisy. Here we propose a numerical methodology for the analysis of optical neuro-imaging data that allows robust analysis of the dynamics of temporal relationships of neural activities. We provide a detailed description of the methodology and we also assess its robustness. The proposed methodology is applied to analyse the relationship between the activity patterns of PY neurons in the crab stomatogastric ganglion. We show for the first time in a physiologically valid setting that as expected on the basis of earlier results of single neuron recordings exposure to dopamine de-synchronises the activity of these neurons. We also discuss the wider implications and application of the proposed methodology.
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Affiliation(s)
- Jannetta S. Steyn
- Bioinformatics Support Unit, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
| | - Peter Andras
- School of Computing and Mathematics, Keele University, Keele, ST5 5BG UK
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7
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Affiliation(s)
- J S Steyn
- Johannesburg, South Africa Late Chief Assistant, University Eye Clinic, Groningen. (Director: Prof. Dr. G. F. Rochat)
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8
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