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Wei Z, Liu C, Liang J, Zhou X, Xue K, Wang K, Zhang X. Characterization of Mitoribosomal Small Subunit unit genes related immune and pharmacogenomic landscapes in renal cell carcinoma. IUBMB Life 2024; 76:647-665. [PMID: 38551358 DOI: 10.1002/iub.2818] [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: 01/16/2024] [Accepted: 02/23/2024] [Indexed: 08/31/2024]
Abstract
Mitoribosomes are essential for the production of biological energy. The Human Mitoribosomal Small Subunit unit (MRPS) family, responsible for encoding mitochondrial ribosomal small subunits, is actively engaged in protein synthesis within the mitochondria. Intriguingly, MRPS family genes appear to play a role in cancer. A multistep process was employed to establish a risk model associated with MRPS genes, aiming to delineate the immune and pharmacogenomic landscapes in clear cell renal cell carcinoma (ccRCC). MRPScores were computed for individual patients to assess their responsiveness to various treatment modalities and their susceptibility to different therapeutic targets and drugs. While MRPS family genes have been implicated in various cancers as oncogenes, our findings reveal a contrasting tumor suppressor role for MRPS genes in ccRCC. Utilizing an MRPS-related risk model, we observed its excellent prognostic capability in predicting survival outcomes for ccRCC patients. Remarkably, the subgroup with high MRPS-related scores (MRPScore) displayed poorer prognosis but exhibited a more robust response to immunotherapy. Through in silico screening of 2183 drug targets and 1646 compounds, we identified two targets (RRM2 and OPRD1) and eight agents (AZ960, carmustine, lasalocid, SGI-1776, AZD8055_1059, BPD.00008900_1998, MK.8776_2046, and XAV939_1268) with potential therapeutic implications for high-MRPScore patients. Our study represents the pioneering effort in proposing that molecular classification, diagnosis, and treatment strategies can be formulated based on MRPScores. Indeed, a high MRPScore profile appears to elevate the risk of tumor progression and mortality, potentially through its influence on immune regulation. This suggests that the MRPS-related risk model holds promise as a prognostic predictor and may offer novel insights into personalized therapeutic strategies.
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Affiliation(s)
- Zhihao Wei
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Urology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chenchen Liu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Urology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiaqian Liang
- Department of Urology, Wuhan No.1 Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xuan Zhou
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Urology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kaming Xue
- Department of Integrated Traditional Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Keshan Wang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Urology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoping Zhang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Institute of Urology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Hilander T, Awadhpersad R, Monteuuis G, Broda KL, Pohjanpelto M, Pyman E, Singh SK, Nyman TA, Crevel I, Taylor RW, Saada A, Balboa D, Battersby BJ, Jackson CB, Carroll CJ. Supernumerary proteins of the human mitochondrial ribosomal small subunit are integral for assembly and translation. iScience 2024; 27:110185. [PMID: 39015150 PMCID: PMC11251090 DOI: 10.1016/j.isci.2024.110185] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 03/28/2024] [Accepted: 06/01/2024] [Indexed: 07/18/2024] Open
Abstract
Mitochondrial ribosomes (mitoribosomes) have undergone substantial evolutionary structural remodeling accompanied by loss of ribosomal RNA, while acquiring unique protein subunits located on the periphery. We generated CRISPR-mediated knockouts of all 14 unique (mitochondria-specific/supernumerary) human mitoribosomal proteins (snMRPs) in the small subunit to study the effect on mitoribosome assembly and protein synthesis, each leading to a unique mitoribosome assembly defect with variable impact on mitochondrial protein synthesis. Surprisingly, the stability of mS37 was reduced in all our snMRP knockouts of the small and large ribosomal subunits and patient-derived lines with mitoribosome assembly defects. A redox-regulated CX9C motif in mS37 was essential for protein stability, suggesting a potential mechanism to regulate mitochondrial protein synthesis. Together, our findings support a modular assembly of the human mitochondrial small ribosomal subunit mediated by essential supernumerary subunits and identify a redox regulatory role involving mS37 in mitochondrial protein synthesis in health and disease.
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Affiliation(s)
- Taru Hilander
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
| | - Ryan Awadhpersad
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Geoffray Monteuuis
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Krystyna L. Broda
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
| | - Max Pohjanpelto
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Elizabeth Pyman
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
| | - Sachin Kumar Singh
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Tuula A. Nyman
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Isabelle Crevel
- Core Facilities, St George’s, University of London, London, UK
| | - Robert W. Taylor
- Mitochondrial Research Group, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 4LP, UK
| | - Ann Saada
- Department of Genetics, Hadassah Medical Center & Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112001 Israel
| | - Diego Balboa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | | | - Christopher B. Jackson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Christopher J. Carroll
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
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3
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Antolínez-Fernández Á, Esteban-Ramos P, Fernández-Moreno MÁ, Clemente P. Molecular pathways in mitochondrial disorders due to a defective mitochondrial protein synthesis. Front Cell Dev Biol 2024; 12:1410245. [PMID: 38855161 PMCID: PMC11157125 DOI: 10.3389/fcell.2024.1410245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/09/2024] [Indexed: 06/11/2024] Open
Abstract
Mitochondria play a central role in cellular metabolism producing the necessary ATP through oxidative phosphorylation. As a remnant of their prokaryotic past, mitochondria contain their own genome, which encodes 13 subunits of the oxidative phosphorylation system, as well as the tRNAs and rRNAs necessary for their translation in the organelle. Mitochondrial protein synthesis depends on the import of a vast array of nuclear-encoded proteins including the mitochondrial ribosome protein components, translation factors, aminoacyl-tRNA synthetases or assembly factors among others. Cryo-EM studies have improved our understanding of the composition of the mitochondrial ribosome and the factors required for mitochondrial protein synthesis and the advances in next-generation sequencing techniques have allowed for the identification of a growing number of genes involved in mitochondrial pathologies with a defective translation. These disorders are often multisystemic, affecting those tissues with a higher energy demand, and often present with neurodegenerative phenotypes. In this article, we review the known proteins required for mitochondrial translation, the disorders that derive from a defective mitochondrial protein synthesis and the animal models that have been established for their study.
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Affiliation(s)
- Álvaro Antolínez-Fernández
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paula Esteban-Ramos
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Miguel Ángel Fernández-Moreno
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paula Clemente
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
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Hughes LA, Rackham O, Filipovska A. Illuminating mitochondrial translation through mouse models. Hum Mol Genet 2024; 33:R61-R79. [PMID: 38779771 PMCID: PMC11112386 DOI: 10.1093/hmg/ddae020] [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: 11/10/2023] [Revised: 01/22/2024] [Accepted: 01/31/2024] [Indexed: 05/25/2024] Open
Abstract
Mitochondria are hubs of metabolic activity with a major role in ATP conversion by oxidative phosphorylation (OXPHOS). The mammalian mitochondrial genome encodes 11 mRNAs encoding 13 OXPHOS proteins along with 2 rRNAs and 22 tRNAs, that facilitate their translation on mitoribosomes. Maintaining the internal production of core OXPHOS subunits requires modulation of the mitochondrial capacity to match the cellular requirements and correct insertion of particularly hydrophobic proteins into the inner mitochondrial membrane. The mitochondrial translation system is essential for energy production and defects result in severe, phenotypically diverse diseases, including mitochondrial diseases that typically affect postmitotic tissues with high metabolic demands. Understanding the complex mechanisms that underlie the pathologies of diseases involving impaired mitochondrial translation is key to tailoring specific treatments and effectively targeting the affected organs. Disease mutations have provided a fundamental, yet limited, understanding of mitochondrial protein synthesis, since effective modification of the mitochondrial genome has proven challenging. However, advances in next generation sequencing, cryoelectron microscopy, and multi-omic technologies have revealed unexpected and unusual features of the mitochondrial protein synthesis machinery in the last decade. Genome editing tools have generated unique models that have accelerated our mechanistic understanding of mitochondrial translation and its physiological importance. Here we review the most recent mouse models of disease pathogenesis caused by defects in mitochondrial protein synthesis and discuss their value for preclinical research and therapeutic development.
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Affiliation(s)
- Laetitia A Hughes
- Telethon Kids Institute, Northern Entrance, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- Harry Perkins Institute of Medical Research, 6 Verdun Street, Nedlands, WA 6009, Australia
- ARC Centre of Excellence in Synthetic Biology, 35 Stirling Highway, Crawley, WA 6009, The University of Western Australia, Crawley, WA 6009, Australia
| | - Oliver Rackham
- Telethon Kids Institute, Northern Entrance, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- Harry Perkins Institute of Medical Research, 6 Verdun Street, Nedlands, WA 6009, Australia
- ARC Centre of Excellence in Synthetic Biology, 35 Stirling Highway, Crawley, WA 6009, The University of Western Australia, Crawley, WA 6009, Australia
- Curtin Medical School, Curtin University, Kent Street, Bentley, WA 6102, Australia
- Curtin Health Innovation Research Institute, Curtin University, Kent Street, Bentley, WA 6102, Australia
| | - Aleksandra Filipovska
- Telethon Kids Institute, Northern Entrance, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- ARC Centre of Excellence in Synthetic Biology, 35 Stirling Highway, Crawley, WA 6009, The University of Western Australia, Crawley, WA 6009, Australia
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, 19 Innovation Walk, Clayton, Clayton, VIC 3168, Australia
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5
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Fair T, Pavlovic BJ, Schaefer NK, Pollen AA. Mapping cis- and trans-regulatory target genes of human-specific deletions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.27.573461. [PMID: 38234800 PMCID: PMC10793408 DOI: 10.1101/2023.12.27.573461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Deletion of functional sequence is predicted to represent a fundamental mechanism of molecular evolution1,2. Comparative genetic studies of primates2,3 have identified thousands of human-specific deletions (hDels), and the cis-regulatory potential of short (≤31 base pairs) hDels has been assessed using reporter assays4. However, how structural variant-sized (≥50 base pairs) hDels influence molecular and cellular processes in their native genomic contexts remains unexplored. Here, we design genome-scale libraries of single-guide RNAs targeting 7.2 megabases of sequence in 6,358 hDels and present a systematic CRISPR interference (CRISPRi) screening approach to identify hDels that modify cellular proliferation in chimpanzee pluripotent stem cells. By intersecting hDels with chromatin state features and performing single-cell CRISPRi (Perturb-seq) to identify their cis- and trans-regulatory target genes, we discovered 19 hDels controlling gene expression. We highlight two hDels, hDel_2247 and hDel_585, with tissue-specific activity in the liver and brain, respectively. Our findings reveal a molecular and cellular role for sequences lost in the human lineage and establish a framework for functionally interrogating human-specific genetic variants.
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Affiliation(s)
- Tyler Fair
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Bryan J Pavlovic
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Nathan K Schaefer
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Alex A Pollen
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
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6
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Amarasekera SSC, Hock DH, Lake NJ, Calvo SE, Grønborg SW, Krzesinski EI, Amor DJ, Fahey MC, Simons C, Wibrand F, Mootha VK, Lek M, Lunke S, Stark Z, Østergaard E, Christodoulou J, Thorburn DR, Stroud DA, Compton AG. Multi-omics identifies large mitoribosomal subunit instability caused by pathogenic MRPL39 variants as a cause of pediatric onset mitochondrial disease. Hum Mol Genet 2023; 32:2441-2454. [PMID: 37133451 PMCID: PMC10360397 DOI: 10.1093/hmg/ddad069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 03/20/2023] [Accepted: 04/24/2023] [Indexed: 05/04/2023] Open
Abstract
MRPL39 encodes one of 52 proteins comprising the large subunit of the mitochondrial ribosome (mitoribosome). In conjunction with 30 proteins in the small subunit, the mitoribosome synthesizes the 13 subunits of the mitochondrial oxidative phosphorylation (OXPHOS) system encoded by mitochondrial Deoxyribonucleic acid (DNA). We used multi-omics and gene matching to identify three unrelated individuals with biallelic variants in MRPL39 presenting with multisystem diseases with severity ranging from lethal, infantile-onset (Leigh syndrome spectrum) to milder with survival into adulthood. Clinical exome sequencing of known disease genes failed to diagnose these patients; however quantitative proteomics identified a specific decrease in the abundance of large but not small mitoribosomal subunits in fibroblasts from the two patients with severe phenotype. Re-analysis of exome sequencing led to the identification of candidate single heterozygous variants in mitoribosomal genes MRPL39 (both patients) and MRPL15. Genome sequencing identified a shared deep intronic MRPL39 variant predicted to generate a cryptic exon, with transcriptomics and targeted studies providing further functional evidence for causation. The patient with the milder disease was homozygous for a missense variant identified through trio exome sequencing. Our study highlights the utility of quantitative proteomics in detecting protein signatures and in characterizing gene-disease associations in exome-unsolved patients. We describe Relative Complex Abundance analysis of proteomics data, a sensitive method that can identify defects in OXPHOS disorders to a similar or greater sensitivity to the traditional enzymology. Relative Complex Abundance has potential utility for functional validation or prioritization in many hundreds of inherited rare diseases where protein complex assembly is disrupted.
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Affiliation(s)
- Sumudu S C Amarasekera
- Murdoch Children’s Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Daniella H Hock
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Nicole J Lake
- Murdoch Children’s Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510 USA
| | - Sarah E Calvo
- Broad Institute, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA 02446, USA
| | - Sabine W Grønborg
- Department of Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen 2100, Denmark
- Center for Inherited Metabolic Disease, Department of Pediatrics and Adolescent Medicine, Copenhagen University Hospital Rigshospitalet, Copenhagen 2100, Denmark
| | - Emma I Krzesinski
- Monash Genetics, Monash Health, Melbourne, VIC 3168 Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168 Australia
| | - David J Amor
- Murdoch Children’s Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Michael C Fahey
- Monash Genetics, Monash Health, Melbourne, VIC 3168 Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168 Australia
| | - Cas Simons
- Murdoch Children’s Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Flemming Wibrand
- Department of Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen 2100, Denmark
| | - Vamsi K Mootha
- Broad Institute, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA 02446, USA
| | - Monkol Lek
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510 USA
| | - Sebastian Lunke
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Australian Genomics Health Alliance, Melbourne, VIC 3052, Australia
- Department of Pathology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Zornitza Stark
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Australian Genomics Health Alliance, Melbourne, VIC 3052, Australia
| | - Elsebet Østergaard
- Department of Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen 2100, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen 2200, Denmark
| | - John Christodoulou
- Murdoch Children’s Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Australian Genomics Health Alliance, Melbourne, VIC 3052, Australia
- Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
| | - David R Thorburn
- Murdoch Children’s Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Australian Genomics Health Alliance, Melbourne, VIC 3052, Australia
| | - David A Stroud
- Murdoch Children’s Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
| | - Alison G Compton
- Murdoch Children’s Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
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Vila-Sanjurjo A, Mallo N, Elson JL, Smith PM, Blakely EL, Taylor RW. Structural analysis of mitochondrial rRNA gene variants identified in patients with deafness. Front Physiol 2023; 14:1163496. [PMID: 37362424 PMCID: PMC10285412 DOI: 10.3389/fphys.2023.1163496] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/18/2023] [Indexed: 06/28/2023] Open
Abstract
The last few years have witnessed dramatic advances in our understanding of the structure and function of the mammalian mito-ribosome. At the same time, the first attempts to elucidate the effects of mito-ribosomal fidelity (decoding accuracy) in disease have been made. Hence, the time is right to push an important frontier in our understanding of mitochondrial genetics, that is, the elucidation of the phenotypic effects of mtDNA variants affecting the functioning of the mito-ribosome. Here, we have assessed the structural and functional role of 93 mitochondrial (mt-) rRNA variants thought to be associated with deafness, including those located at non-conserved positions. Our analysis has used the structural description of the human mito-ribosome of the highest quality currently available, together with a new understanding of the phenotypic manifestation of mito-ribosomal-associated variants. Basically, any base change capable of inducing a fidelity phenotype may be considered non-silent. Under this light, out of 92 previously reported mt-rRNA variants thought to be associated with deafness, we found that 49 were potentially non-silent. We also dismissed a large number of reportedly pathogenic mtDNA variants, 41, as polymorphisms. These results drastically update our view on the implication of the primary sequence of mt-rRNA in the etiology of deafness and mitochondrial disease in general. Our data sheds much-needed light on the question of how mt-rRNA variants located at non-conserved positions may lead to mitochondrial disease and, most notably, provide evidence of the effect of haplotype context in the manifestation of some mt-rRNA variants.
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Affiliation(s)
- Antón Vila-Sanjurjo
- Grupo GIBE. Departamento de Bioloxía e Centro Interdisciplinar de Química e Bioloxía (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Natalia Mallo
- Grupo GIBE. Departamento de Bioloxía e Centro Interdisciplinar de Química e Bioloxía (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Joanna L. Elson
- The Bioscience Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- Human Metabolomics, North-West University, Potchefstroom, South Africa
| | - Paul M. Smith
- Department of Paediatrics, Raigmore Hospital, Inverness, United Kingdom
| | - Emma L. Blakely
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
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8
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Huang Y, Zhou B. Mitochondrial Dysfunction in Cardiac Diseases and Therapeutic Strategies. Biomedicines 2023; 11:biomedicines11051500. [PMID: 37239170 DOI: 10.3390/biomedicines11051500] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Mitochondria are the main site of intracellular synthesis of ATP, which provides energy for various physiological activities of the cell. Cardiomyocytes have a high density of mitochondria and mitochondrial damage is present in a variety of cardiovascular diseases. In this paper, we describe mitochondrial damage in mitochondrial cardiomyopathy, congenital heart disease, coronary heart disease, myocardial ischemia-reperfusion injury, heart failure, and drug-induced cardiotoxicity, in the context of the key roles of mitochondria in cardiac development and homeostasis. Finally, we discuss the main current therapeutic strategies aimed at alleviating mitochondrial impairment-related cardiac dysfunction, including pharmacological strategies, gene therapy, mitochondrial replacement therapy, and mitochondrial transplantation. It is hoped that this will provide new ideas for the treatment of cardiovascular diseases.
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Affiliation(s)
- Yafei Huang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Science and Peking Union Medical College, 167 North Lishi Road, Xicheng District, Beijing 100037, China
| | - Bingying Zhou
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Science and Peking Union Medical College, 167 North Lishi Road, Xicheng District, Beijing 100037, China
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9
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Bakhshalizadeh S, Hock DH, Siddall NA, Kline BL, Sreenivasan R, Bell KM, Casagranda F, Kamalanathan S, Sahoo J, Narayanan N, Naik D, Suryadevara V, Compton AG, Amarasekera SSC, Kapoor R, Jaillard S, Simpson A, Robevska G, van den Bergen J, Pachernegg S, Ayers KL, Thorburn DR, Stroud DA, Hime GR, Sinclair AH, Tucker EJ. Deficiency of the mitochondrial ribosomal subunit, MRPL50, causes autosomal recessive syndromic premature ovarian insufficiency. Hum Genet 2023:10.1007/s00439-023-02563-z. [PMID: 37148394 DOI: 10.1007/s00439-023-02563-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 04/19/2023] [Indexed: 05/08/2023]
Abstract
Premature ovarian insufficiency (POI) is a common cause of infertility in women, characterised by amenorrhea and elevated FSH under the age of 40 years. In some cases, POI is syndromic in association with other features such as sensorineural hearing loss in Perrault syndrome. POI is a heterogeneous disease with over 80 causative genes known so far; however, these explain only a minority of cases. Using whole-exome sequencing (WES), we identified a MRPL50 homozygous missense variant (c.335T > A; p.Val112Asp) shared by twin sisters presenting with POI, bilateral high-frequency sensorineural hearing loss, kidney and heart dysfunction. MRPL50 encodes a component of the large subunit of the mitochondrial ribosome. Using quantitative proteomics and western blot analysis on patient fibroblasts, we demonstrated a loss of MRPL50 protein and an associated destabilisation of the large subunit of the mitochondrial ribosome whilst the small subunit was preserved. The mitochondrial ribosome is responsible for the translation of subunits of the mitochondrial oxidative phosphorylation machinery, and we found patient fibroblasts have a mild but significant decrease in the abundance of mitochondrial complex I. These data support a biochemical phenotype associated with MRPL50 variants. We validated the association of MRPL50 with the clinical phenotype by knockdown/knockout of mRpL50 in Drosophila, which resulted abnormal ovarian development. In conclusion, we have shown that a MRPL50 missense variant destabilises the mitochondrial ribosome, leading to oxidative phosphorylation deficiency and syndromic POI, highlighting the importance of mitochondrial support in ovarian development and function.
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Affiliation(s)
- Shabnam Bakhshalizadeh
- Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Daniella H Hock
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Nicole A Siddall
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | | | - Rajini Sreenivasan
- Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Katrina M Bell
- Department of Bioinformatics, Murdoch Children's Research Institute, Melbourne, Australia
| | - Franca Casagranda
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | - Sadishkumar Kamalanathan
- Department of Endocrinology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, 605006, India
| | - Jayaprakash Sahoo
- Department of Endocrinology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, 605006, India
| | - Niya Narayanan
- Department of Endocrinology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, 605006, India
| | - Dukhabandhu Naik
- Department of Endocrinology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, 605006, India
| | - Varun Suryadevara
- Department of Endocrinology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, 605006, India
| | - Alison G Compton
- Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
- Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia
| | - Sumudu S C Amarasekera
- Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Ridam Kapoor
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | - Sylvie Jaillard
- Univ Rennes, CHU Rennes, INSERM, EHESP, IRSET (Institut de Recherche en Santé, Environnement et Travail) - UMR_S 1085, 35000, Rennes, France
- CHU Rennes, Service de Cytogénétique et Biologie Cellulaire, 35033, Rennes, France
| | - Andrea Simpson
- School of Allied Health, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC, Australia
- College of Health and Human Services, Charles Darwin University, Darwin, NT, Australia
| | | | | | - Svenja Pachernegg
- Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Katie L Ayers
- Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - David R Thorburn
- Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
- Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia
| | - David A Stroud
- Murdoch Children's Research Institute, Melbourne, Australia
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
- Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia
| | - Gary R Hime
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia.
| | - Andrew H Sinclair
- Murdoch Children's Research Institute, Melbourne, Australia.
- Department of Paediatrics, University of Melbourne, Melbourne, Australia.
| | - Elena J Tucker
- Murdoch Children's Research Institute, Melbourne, Australia.
- Department of Paediatrics, University of Melbourne, Melbourne, Australia.
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10
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Snezhkina A, Pavlov V, Fedorova M, Kalinin D, Pudova E, Kobelyatskaya A, Bakhtogarimov I, Krasnov G, Kudryavtseva A. Comprehensive Genetic Study of Malignant Cervical Paraganglioma. Int J Mol Sci 2023; 24:ijms24098220. [PMID: 37175927 PMCID: PMC10179044 DOI: 10.3390/ijms24098220] [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: 04/03/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Malignant middle ear paraganglioma (MEPGL) is an exceedingly rare tumor of the neuroendocrine system. In general, MEPGLs represent as slow growing and hypervascularized benign neoplasms. The genetic basis of MEPGL tumorigenesis has been poorly investigated. We report a case of malignant MEPGL accompanied by the comprehensive genetic analysis of the primary tumor and metastasis. Based on whole-exome sequencing data, the germline pathogenic mutation p.R230H in the SDHB gene, encoding for subunit B of mitochondrial complex II, was found in a patient. Analysis of somatic mutation spectra revealed five novel variants in different genes, including a potentially deleterious variant in UNC13C that was common for the tumor and metastasis. Identified somatic variants clustered into SBS1 and SBS5 mutational signatures. Of note, the primary tumor was characterized by Ki-67 4% and had an elevated mutational load (1.4/Mb); the metastasis' mutational load was about 4.5 times higher (6.4/Mb). In addition, we revealed somatic loss of the wild-type SDHB allele, as well as loss of heterozygosity (LOH) at the 11p locus. Thus, germline mutation in SDHB combined with somatic LOH seem to be drivers that lead to the tumor's initiation and progression. Other somatic changes identified can be additional disease-causing factors. Obtained results expand our understanding of molecular genetic mechanisms associated with the development of this rare tumor.
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Affiliation(s)
- Anastasiya Snezhkina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Vladislav Pavlov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Maria Fedorova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Dmitry Kalinin
- Vishnevsky Institute of Surgery, Ministry of Health of the Russian Federation, 117997 Moscow, Russia
| | - Elena Pudova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | | | - Ildar Bakhtogarimov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - George Krasnov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Anna Kudryavtseva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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11
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Jerome MS, Nanjappa DP, Chakraborty A, Chakrabarty S. Molecular etiology of defective nuclear and mitochondrial ribosome biogenesis: Clinical phenotypes and therapy. Biochimie 2023; 207:122-136. [PMID: 36336106 DOI: 10.1016/j.biochi.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/27/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
Abstract
Ribosomopathies are rare congenital disorders associated with defective ribosome biogenesis due to pathogenic variations in genes that encode proteins related to ribosome function and biogenesis. Defects in ribosome biogenesis result in a nucleolar stress response involving the TP53 tumor suppressor protein and impaired protein synthesis leading to a deregulated translational output. Despite the accepted notion that ribosomes are omnipresent and essential for all cells, most ribosomopathies show tissue-specific phenotypes affecting blood cells, hair, spleen, or skin. On the other hand, defects in mitochondrial ribosome biogenesis are associated with a range of clinical manifestations affecting more than one organ. Intriguingly, the deregulated ribosomal function is also a feature in several human malignancies with a selective upregulation or downregulation of specific ribosome components. Here, we highlight the clinical conditions associated with defective ribosome biogenesis in the nucleus and mitochondria with a description of the affected genes and the implicated pathways, along with a note on the treatment strategies currently available for these disorders.
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Affiliation(s)
- Maria Sona Jerome
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India
| | - Dechamma Pandyanda Nanjappa
- Division of Molecular Genetics and Cancer, Nitte University Centre for Science Education and Research (NUCSER), NITTE (Deemed to Be University), Deralakate, Mangaluru, 575018, India
| | - Anirban Chakraborty
- Division of Molecular Genetics and Cancer, Nitte University Centre for Science Education and Research (NUCSER), NITTE (Deemed to Be University), Deralakate, Mangaluru, 575018, India.
| | - Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India.
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12
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Thompson K, Stroud DA, Thorburn DR, Taylor RW. Investigation of oxidative phosphorylation activity and complex composition in mitochondrial disease. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:127-139. [PMID: 36813309 DOI: 10.1016/b978-0-12-821751-1.00008-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
A multidisciplinary approach to the laboratory diagnosis of mitochondrial disease has long been applied, with crucial information provided by deep clinical phenotyping, blood investigations, and biomarker screening as well as histopathological and biochemical testing of biopsy material to support molecular genetic screening. In an era of second and third generation sequencing technologies, traditional diagnostic algorithms for mitochondrial disease have been replaced by gene agnostic, genomic strategies including whole-exome sequencing (WES) and whole-genome sequencing (WGS), increasingly supported by other 'omics technologies (Alston et al., 2021). Whether a primary testing strategy, or one used to validate and interpret candidate genetic variants, the availability of a range of tests aimed at determining mitochondrial function (i.e., the assessment of individual respiratory chain enzyme activities in a tissue biopsy or cellular respiration in a patient cell line) remains an important part of the diagnostic armory. In this chapter, we summarize several disciplines used in the laboratory investigation of suspected mitochondrial disease, including the histopathological and biochemical assessment of mitochondrial function, as well as protein-based techniques to assess the steady-state levels of oxidative phosphorylation (OXPHOS) subunits and assembly of OXPHOS complexes via traditional (immunoblotting) and cutting-edge (quantitative proteomic) approaches.
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Affiliation(s)
- Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David A Stroud
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia; Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - David R Thorburn
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia; Mitochondrial Laboratory, Victorian Clinical Genetic Services, Melbourne, VIC, Australia
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom; NHS Highly Specialised Services for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom.
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13
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Genetics of mitochondrial diseases: Current approaches for the molecular diagnosis. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:141-165. [PMID: 36813310 DOI: 10.1016/b978-0-12-821751-1.00011-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Mitochondrial diseases are a genetically and phenotypically variable set of monogenic disorders. The main characteristic of mitochondrial diseases is a defective oxidative phosphorylation. Both nuclear and mitochondrial DNA encode the approximately 1500 mitochondrial proteins. Since identification of the first mitochondrial disease gene in 1988 a total of 425 genes have been associated with mitochondrial diseases. Mitochondrial dysfunctions can be caused both by pathogenic variants in the mitochondrial DNA or the nuclear DNA. Hence, besides maternal inheritance, mitochondrial diseases can follow all modes of Mendelian inheritance. The maternal inheritance and tissue specificity distinguish molecular diagnostics of mitochondrial disorders from other rare disorders. With the advances made in the next-generation sequencing technology, whole exome sequencing and even whole-genome sequencing are now the established methods of choice for molecular diagnostics of mitochondrial diseases. They reach a diagnostic rate of more than 50% in clinically suspected mitochondrial disease patients. Moreover, next-generation sequencing is delivering a constantly growing number of novel mitochondrial disease genes. This chapter reviews mitochondrial and nuclear causes of mitochondrial diseases, molecular diagnostic methodologies, and their current challenges and perspectives.
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14
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Silencing of the mitochondrial ribosomal protein L-24 gene activates the oxidative stress response in Caenorhabditis elegans. Biochim Biophys Acta Gen Subj 2023; 1867:130255. [PMID: 36265765 DOI: 10.1016/j.bbagen.2022.130255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 10/09/2022] [Accepted: 10/12/2022] [Indexed: 11/13/2022]
Abstract
The mitochondrial translation machinery allows the synthesis of the mitochondrial-encoded subunits of the electron transport chain. Defects in this process lead to mitochondrial physiology failure; in humans, they are associated with early-onset, extremely variable and often fatal disorder. The use of a simple model to study the mitoribosomal defects is mandatory to overcome the difficulty to analyze the impact of pathological mutations in humans. In this paper we study in nematode Caenorhabditis elegans the silencing effect of the mrpl-24 gene, coding for the mitochondrial ribosomal protein L-24 (MRPL-24). This is a structural protein of the large subunit 39S of the mitoribosome and its effective physiological function is not completely elucidated. We have evaluated the nematode's fitness fault and investigated the mitochondrial defects associated with MRPL-24 depletion. The oxidative stress response activation due to the mitochondrial alteration has been also investigated as a compensatory physiological mechanism. For the first time, we demonstrated that MRPL-24 reduction increases the expression of detoxifying enzymes such as SOD-3 and GST-4 through the involvement of transcription factor SKN-1. BACKGROUND In humans, mutations in genes encoding mitochondrial ribosomal proteins (MRPs) often cause early-onset, severe, fatal and extremely variable clinical defects. Mitochondrial ribosomal protein L-24 (MRPL24) is a structural protein of the large subunit 39S of the mitoribosome. It is highly conserved in different species and its effective physiological function is not completely elucidated. METHODS We characterized the MRPL24 functionality using the animal model Caenorhabditis elegans. We performed the RNA mediated interference (RNAi) by exposing the nematodes' embryos to double-stranded RNA (dsRNA) specific for the MRPL-24 coding sequence. We investigated for the first time in C. elegans, the involvement of the MRPL-24 on the nematode's fitness and its mitochondrial physiology. RESULTS Mrpl-24 silencing in C. elegans negatively affected the larval development, progeny production and body bending. The analysis of mitochondrial functionality revealed loss of mitochondrial network and impairment of mitochondrial functionality, as the decrease of oxygen consumption rate and the ROS production, as well as reduction of mitochondrial protein synthesis. Finally, the MRPL-24 depletion activated the oxidative stress response, increasing the expression levels of two detoxifying enzymes, SOD-3 and GST-4. CONCLUSIONS In C. elegans the MRPL-24 depletion activated the oxidative stress response. This appears as a compensatory mechanism to the alteration of the mitochondrial functionality and requires the involvement of transcription factor SKN-1. GENERAL SIGNIFICANCE C. elegans resulted in a good model for the study of mitochondrial disorders and its use as a simple and pluricellular organism could open interesting perspectives to better investigate the pathologic mechanisms underlying these devastating diseases.
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15
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Ng KY, Battersby BJ. Sucrose Gradient Analysis of Human Mitochondrial Ribosomes and RNA. Methods Mol Biol 2023; 2661:101-117. [PMID: 37166634 DOI: 10.1007/978-1-0716-3171-3_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Faithful expression of the mitochondrial genome is required for the synthesis of the oxidative phosphorylation complexes and cell fitness. In humans, mitochondrial DNA (mtDNA) encodes 13 essential subunits of four oxidative phosphorylation complexes along with tRNAs and rRNAs needed for the translation of these proteins. Protein synthesis occurs on unique ribosomes within the organelle. Over the last decade, the revolution in genetic diagnostics has identified disruptions to the faithful synthesis of these 13 mitochondrial proteins as the largest group of inherited human mitochondrial pathologies. All of the molecular steps required for mitochondrial protein synthesis can be affected, from the genome to protein, including cotranslational quality control. Here, we describe methodologies for the biochemical separation of mitochondrial ribosomes from cultured human cells for RNA and protein analysis. Our method has been optimized to facilitate analysis for low-level sample material and thus does not require prior organelle enrichment.
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Affiliation(s)
- Kah Ying Ng
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Brendan J Battersby
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.
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16
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Muñoz‐Pujol G, Ortigoza‐Escobar JD, Paredes‐Fuentes AJ, Jou C, Ugarteburu O, Gort L, Yubero D, García‐Cazorla A, O'Callaghan M, Campistol J, Muchart J, Yépez VA, Gusic M, Gagneur J, Prokisch H, Artuch R, Ribes A, Urreizti R, Tort F. Leigh syndrome is the main clinical characteristic of
PTCD3
deficiency. Brain Pathol 2022; 33:e13134. [PMID: 36450274 PMCID: PMC10154364 DOI: 10.1111/bpa.13134] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 11/16/2022] [Indexed: 12/05/2022] Open
Abstract
Mitochondrial translation defects are a continuously growing group of disorders showing a large variety of clinical symptoms including a wide range of neurological abnormalities. To date, mutations in PTCD3, encoding a component of the mitochondrial ribosome, have only been reported in a single individual with clinical evidence of Leigh syndrome. Here, we describe three additional PTCD3 individuals from two unrelated families, broadening the genetic and phenotypic spectrum of this disorder, and provide definitive evidence that PTCD3 deficiency is associated with Leigh syndrome. The patients presented in the first months of life with psychomotor delay, respiratory insufficiency and feeding difficulties. The neurologic phenotype included dystonia, optic atrophy, nystagmus and tonic-clonic seizures. Brain MRI showed optic nerve atrophy and thalamic changes, consistent with Leigh syndrome. WES and RNA-seq identified compound heterozygous variants in PTCD3 in both families: c.[1453-1G>C];[1918C>G] and c.[710del];[902C>T]. The functional consequences of the identified variants were determined by a comprehensive characterization of the mitochondrial function. PTCD3 protein levels were significantly reduced in patient fibroblasts and, consistent with a mitochondrial translation defect, a severe reduction in the steady state levels of complexes I and IV subunits was detected. Accordingly, the activity of these complexes was also low, and high-resolution respirometry showed a significant decrease in the mitochondrial respiratory capacity. Functional complementation studies demonstrated the pathogenic effect of the identified variants since the expression of wild-type PTCD3 in immortalized fibroblasts restored the steady-state levels of complexes I and IV subunits as well as the mitochondrial respiratory capacity. Additionally, minigene assays demonstrated that three of the identified variants were pathogenic by altering PTCD3 mRNA processing. The fourth variant was a frameshift leading to a truncated protein. In summary, we provide evidence of PTCD3 involvement in human disease confirming that PTCD3 deficiency is definitively associated with Leigh syndrome.
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Affiliation(s)
- Gerard Muñoz‐Pujol
- Secció d'Errors Congènits del Metabolisme‐IBC, Servei de Bioquímica i Genètica Molecular Hospital Clínic de Barcelona, IDIBAPS, CIBERER Barcelona Spain
| | | | - Abraham J. Paredes‐Fuentes
- Clinical Biochemistry and Molecular Medicine and Genetics Departments Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, and CIBERER Esplugues de Llobregat Barcelona Spain
| | - Cristina Jou
- Pathology Department, Institut de Recerca Sant Joan de Déu Hospital Sant Joan de Déu, University of Barcelona, CIBERER Esplugues de Llobregat Barcelona Spain
| | - Olatz Ugarteburu
- Secció d'Errors Congènits del Metabolisme‐IBC, Servei de Bioquímica i Genètica Molecular Hospital Clínic de Barcelona, IDIBAPS, CIBERER Barcelona Spain
| | - Laura Gort
- Secció d'Errors Congènits del Metabolisme‐IBC, Servei de Bioquímica i Genètica Molecular Hospital Clínic de Barcelona, IDIBAPS, CIBERER Barcelona Spain
| | - Delia Yubero
- Clinical Biochemistry and Molecular Medicine and Genetics Departments Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, and CIBERER Esplugues de Llobregat Barcelona Spain
| | - Angels García‐Cazorla
- Pediatric Neurology Department Hospital Sant Joan de Déu Esplugues de Llobregat Barcelona Spain
| | - Mar O'Callaghan
- Pediatric Neurology Department Hospital Sant Joan de Déu Esplugues de Llobregat Barcelona Spain
| | - Jaume Campistol
- Pediatric Neurology Department Hospital Sant Joan de Déu Esplugues de Llobregat Barcelona Spain
| | - Jordi Muchart
- Pediatric Radiology Department Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu Esplugues de Llobregat Barcelona Spain
| | - Vicente A. Yépez
- School of Medicine Institute of Human Genetics, Technische Universität München Munich Germany
- Department of Informatics Technical University of Munich Garching Germany
| | - Mirjana Gusic
- School of Medicine Institute of Human Genetics, Technische Universität München Munich Germany
- Institute of Neurogenomics, Helmholtz Zentrum München Neuherberg Germany
| | - Julien Gagneur
- School of Medicine Institute of Human Genetics, Technische Universität München Munich Germany
- Department of Informatics Technical University of Munich Garching Germany
| | - Holger Prokisch
- School of Medicine Institute of Human Genetics, Technische Universität München Munich Germany
- Institute of Neurogenomics, Helmholtz Zentrum München Neuherberg Germany
| | - Rafael Artuch
- Clinical Biochemistry and Molecular Medicine and Genetics Departments Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, and CIBERER Esplugues de Llobregat Barcelona Spain
| | - Antonia Ribes
- Secció d'Errors Congènits del Metabolisme‐IBC, Servei de Bioquímica i Genètica Molecular Hospital Clínic de Barcelona, IDIBAPS, CIBERER Barcelona Spain
| | - Roser Urreizti
- Clinical Biochemistry and Molecular Medicine and Genetics Departments Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, and CIBERER Esplugues de Llobregat Barcelona Spain
| | - Frederic Tort
- Secció d'Errors Congènits del Metabolisme‐IBC, Servei de Bioquímica i Genètica Molecular Hospital Clínic de Barcelona, IDIBAPS, CIBERER Barcelona Spain
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17
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Kline BL, Jaillard S, Bell KM, Bakhshalizadeh S, Robevska G, van den Bergen J, Dulon J, Ayers KL, Christodoulou J, Tchan MC, Touraine P, Sinclair AH, Tucker EJ. Integral Role of the Mitochondrial Ribosome in Supporting Ovarian Function: MRPS7 Variants in Syndromic Premature Ovarian Insufficiency. Genes (Basel) 2022; 13:2113. [PMID: 36421788 PMCID: PMC9690861 DOI: 10.3390/genes13112113] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/09/2022] [Accepted: 11/11/2022] [Indexed: 10/03/2023] Open
Abstract
The mitochondrial ribosome is critical to mitochondrial protein synthesis. Defects in both the large and small subunits of the mitochondrial ribosome can cause human disease, including, but not limited to, cardiomyopathy, hypoglycaemia, neurological dysfunction, sensorineural hearing loss and premature ovarian insufficiency (POI). POI is a common cause of infertility, characterised by elevated follicle-stimulating hormone and amenorrhea in women under the age of 40. Here we describe a patient with POI, sensorineural hearing loss and Hashimoto's disease. The co-occurrence of POI with sensorineural hearing loss indicates Perrault syndrome. Whole exome sequencing identified two compound heterozygous variants in mitochondrial ribosomal protein 7 (MRPS7), c.373A>T/p.(Lys125*) and c.536G>A/p.(Arg179His). Both novel variants are predicted to be pathogenic via in-silico algorithms. Variants in MRPS7 have been described only once in the literature and were identified in sisters, one of whom presented with congenital sensorineural hearing loss and POI, consistent with our patient phenotype. The other affected sister had a more severe disease course and died in early adolescence due to liver and renal failure before the reproductive phenotype was known. This second independent report validates that variants in MRPS7 are a cause of syndromic POI/Perrault syndrome. We present this case and review the current evidence supporting the integral role of the mitochondrial ribosome in supporting ovarian function.
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Affiliation(s)
- Brianna L. Kline
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Sylvie Jaillard
- IRSET (Institut de Recherche en Santé, Environnement et Travail), INSERM/EHESP/Univ Rennes/CHU Rennes–UMR_S 1085, F-35000 Rennes, France
- CHU Rennes, Service de Cytogénétique et Biologie Cellulaire, F-35033 Rennes, France
| | - Katrina M. Bell
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Shabnam Bakhshalizadeh
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Gorjana Robevska
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Jocelyn van den Bergen
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Jérôme Dulon
- Department of Endocrinology and Reproductive Medicine, AP-HP, Sorbonne University Medicine, Centre de Référence des Maladies Endocriniennes Rares de la Croissance et du Développement, Centre des Pathologies Gynécologiques Rares, 75231 Paris, France
| | - Katie L. Ayers
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - John Christodoulou
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Michel C. Tchan
- Department of Genetic Medicine, Westmead Hospital, Sydney, NSW 2145, Australia
| | - Philippe Touraine
- Department of Endocrinology and Reproductive Medicine, AP-HP, Sorbonne University Medicine, Centre de Référence des Maladies Endocriniennes Rares de la Croissance et du Développement, Centre des Pathologies Gynécologiques Rares, 75231 Paris, France
| | - Andrew H. Sinclair
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Elena J. Tucker
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
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18
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Maurya SK, Gupta S, Bakshi A, Kaur H, Jain A, Senapati S, Baghel MS. Targeting mitochondria in the regulation of neurodegenerative diseases: A comprehensive review. J Neurosci Res 2022; 100:1845-1861. [PMID: 35856508 DOI: 10.1002/jnr.25110] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 06/21/2022] [Accepted: 07/09/2022] [Indexed: 11/09/2022]
Abstract
Mitochondria are one of the essential cellular organelles. Apart from being considered as the powerhouse of the cell, mitochondria have been widely known to regulate redox reaction, inflammation, cell survival, cell death, metabolism, etc., and are implicated in the progression of numerous disease conditions including neurodegenerative diseases. Since brain is an energy-demanding organ, mitochondria and their functions are important for maintaining normal brain homeostasis. Alterations in mitochondrial gene expression, mutations, and epigenetic modification contribute to inflammation and neurodegeneration. Dysregulation of reactive oxygen species production by mitochondria and aggregation of proteins in neurons leads to alteration in mitochondria functions which further causes neuronal death and progression of neurodegeneration. Pharmacological studies have prioritized mitochondria as a possible drug target in the regulation of neurodegenerative diseases. Therefore, the present review article has been intended to provide a comprehensive understanding of mitochondrial role in the development and progression of neurodegenerative diseases mainly Alzheimer's, Parkinson's, multiple sclerosis, and amyotrophic lateral sclerosis followed by possible intervention and future treatment strategies to combat mitochondrial-mediated neurodegeneration.
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Affiliation(s)
| | - Suchi Gupta
- Stem Cell Facility, All India Institute of Medical Sciences, Delhi, India
| | - Amrita Bakshi
- Department of Zoology, University of Delhi, Delhi, India
| | - Harpreet Kaur
- Department of Zoology, University of Delhi, Delhi, India.,Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Arushi Jain
- Immunogenomics Laboratory, Department of Human Genetics & Molecular Medicine, Central University of Punjab, Bathinda, India
| | - Sabyasachi Senapati
- Immunogenomics Laboratory, Department of Human Genetics & Molecular Medicine, Central University of Punjab, Bathinda, India
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19
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Ng KY, Richter U, Jackson CB, Seneca S, Battersby BJ. Translation of MT-ATP6 pathogenic variants reveals distinct regulatory consequences from the co-translational quality control of mitochondrial protein synthesis. Hum Mol Genet 2021; 31:1230-1241. [PMID: 34718584 PMCID: PMC9029222 DOI: 10.1093/hmg/ddab314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 11/16/2022] Open
Abstract
Pathogenic variants that disrupt human mitochondrial protein synthesis are associated with a clinically heterogeneous group of diseases. Despite an impairment in oxidative phosphorylation being a common phenotype, the underlying molecular pathogenesis is more complex than simply a bioenergetic deficiency. Currently, we have limited mechanistic understanding on the scope by which a primary defect in mitochondrial protein synthesis contributes to organelle dysfunction. Since the proteins encoded in the mitochondrial genome are hydrophobic and need co-translational insertion into a lipid bilayer, responsive quality control mechanisms are required to resolve aberrations that arise with the synthesis of truncated and misfolded proteins. Here, we show that defects in the OXA1L-mediated insertion of MT-ATP6 nascent chains into the mitochondrial inner membrane are rapidly resolved by the AFG3L2 protease complex. Using pathogenic MT-ATP6 variants, we then reveal discrete steps in this quality control mechanism and the differential functional consequences to mitochondrial gene expression. The inherent ability of a given cell type to recognize and resolve impairments in mitochondrial protein synthesis may in part contribute at the molecular level to the wide clinical spectrum of these disorders.
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Affiliation(s)
- Kah Ying Ng
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Uwe Richter
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Wellcome Centre for Mitochondrial Research, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Christopher B Jackson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sara Seneca
- Center for Medical Genetics/Research Center Reproduction and Genetics, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels, Belgium
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20
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Alsharhan H, Muraresku C, Ganetzky RD. COXPD9 in an individual from Puerto Rico and literature review. Am J Med Genet A 2021; 185:2519-2525. [PMID: 34008913 DOI: 10.1002/ajmg.a.62344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 04/28/2021] [Accepted: 05/02/2021] [Indexed: 11/07/2022]
Abstract
Defects of mitoribosome assembly with destabilization of mitochondrial ribosomal proteins and subsequent aberrant mitochondrial translation machinery are one of the emerging categories of human mitochondrial disease. Mitochondrial translation deficiency constitutes a growing cause of combined oxidative phosphorylation deficiency and overall causes a set of clinically heterogeneous multi-systemic diseases. We present here the sixth individual with combined oxidative phosphorylation deficiency-9 (COXPD9) secondary to a likely pathogenic homozygous MRPL3 variant c.571A > C; p.(Thr191Pro). MRPL3 encodes a large mitochondrial ribosome subunit protein, impairing the mitochondrial translation and resulting in multisystem disease. Similar to previously reported individuals, this reported female proband presented with psychomotor retardation, sensorineural hearing loss, hypertrophic cardiomyopathy, failure to thrive, and lactic acidosis. Further, she has additional, previously unreported, features including Leigh syndrome, cataracts, hypotonia, scoliosis, myopathy, exercise intolerance, childhood-onset cardiomyopathy, and microcephaly. This subject is the oldest reported individual with COXPD9. This report also summarizes the clinical and molecular data of the previously reported individuals with COXPD9 to describe the full phenotypic spectrum.
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Affiliation(s)
- Hind Alsharhan
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Division of Human Genetics, Section of Biochemical Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Colleen Muraresku
- Division of Human Genetics, Section of Biochemical Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Rebecca D Ganetzky
- Division of Human Genetics, Section of Biochemical Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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21
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Human Mitoribosome Biogenesis and Its Emerging Links to Disease. Int J Mol Sci 2021; 22:ijms22083827. [PMID: 33917098 PMCID: PMC8067846 DOI: 10.3390/ijms22083827] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/20/2022] Open
Abstract
Mammalian mitochondrial ribosomes (mitoribosomes) synthesize a small subset of proteins, which are essential components of the oxidative phosphorylation machinery. Therefore, their function is of fundamental importance to cellular metabolism. The assembly of mitoribosomes is a complex process that progresses through numerous maturation and protein-binding events coordinated by the actions of several assembly factors. Dysregulation of mitoribosome production is increasingly recognized as a contributor to metabolic and neurodegenerative diseases. In recent years, mutations in multiple components of the mitoribosome assembly machinery have been associated with a range of human pathologies, highlighting their importance to cell function and health. Here, we provide a review of our current understanding of mitoribosome biogenesis, highlighting the key factors involved in this process and the growing number of mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors that lead to human disease.
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22
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Blackout in the powerhouse: clinical phenotypes associated with defects in the assembly of OXPHOS complexes and the mitoribosome. Biochem J 2021; 477:4085-4132. [PMID: 33151299 PMCID: PMC7657662 DOI: 10.1042/bcj20190767] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria produce the bulk of the energy used by almost all eukaryotic cells through oxidative phosphorylation (OXPHOS) which occurs on the four complexes of the respiratory chain and the F1–F0 ATPase. Mitochondrial diseases are a heterogenous group of conditions affecting OXPHOS, either directly through mutation of genes encoding subunits of OXPHOS complexes, or indirectly through mutations in genes encoding proteins supporting this process. These include proteins that promote assembly of the OXPHOS complexes, the post-translational modification of subunits, insertion of cofactors or indeed subunit synthesis. The latter is important for all 13 of the proteins encoded by human mitochondrial DNA, which are synthesised on mitochondrial ribosomes. Together the five OXPHOS complexes and the mitochondrial ribosome are comprised of more than 160 subunits and many more proteins support their biogenesis. Mutations in both nuclear and mitochondrial genes encoding these proteins have been reported to cause mitochondrial disease, many leading to defective complex assembly with the severity of the assembly defect reflecting the severity of the disease. This review aims to act as an interface between the clinical and basic research underpinning our knowledge of OXPHOS complex and ribosome assembly, and the dysfunction of this process in mitochondrial disease.
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23
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Mechanisms and regulation of protein synthesis in mitochondria. Nat Rev Mol Cell Biol 2021; 22:307-325. [PMID: 33594280 DOI: 10.1038/s41580-021-00332-2] [Citation(s) in RCA: 159] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2021] [Indexed: 02/06/2023]
Abstract
Mitochondria are cellular organelles responsible for generation of chemical energy in the process called oxidative phosphorylation. They originate from a bacterial ancestor and maintain their own genome, which is expressed by designated, mitochondrial transcription and translation machineries that differ from those operating for nuclear gene expression. In particular, the mitochondrial protein synthesis machinery is structurally and functionally very different from that governing eukaryotic, cytosolic translation. Despite harbouring their own genetic information, mitochondria are far from being independent of the rest of the cell and, conversely, cellular fitness is closely linked to mitochondrial function. Mitochondria depend heavily on the import of nuclear-encoded proteins for gene expression and function, and hence engage in extensive inter-compartmental crosstalk to regulate their proteome. This connectivity allows mitochondria to adapt to changes in cellular conditions and also mediates responses to stress and mitochondrial dysfunction. With a focus on mammals and yeast, we review fundamental insights that have been made into the biogenesis, architecture and mechanisms of the mitochondrial translation apparatus in the past years owing to the emergence of numerous near-atomic structures and a considerable amount of biochemical work. Moreover, we discuss how cellular mitochondrial protein expression is regulated, including aspects of mRNA and tRNA maturation and stability, roles of auxiliary factors, such as translation regulators, that adapt mitochondrial translation rates, and the importance of inter-compartmental crosstalk with nuclear gene expression and cytosolic translation and how it enables integration of mitochondrial translation into the cellular context.
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24
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Role of GTPases in Driving Mitoribosome Assembly. Trends Cell Biol 2021; 31:284-297. [PMID: 33419649 DOI: 10.1016/j.tcb.2020.12.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/01/2020] [Accepted: 12/11/2020] [Indexed: 01/08/2023]
Abstract
Mitoribosomes catalyze essential protein synthesis within mitochondria. Mitoribosome biogenesis is assisted by an increasing number of assembly factors, among which guanosine triphosphate hydrolases (GTPases) are the most abundant class. Here, we review recent progress in our understanding of mitoribosome assembly GTPases. We describe their shared and specific features and mechanisms of action, compare them with their bacterial counterparts, and discuss their possible roles in the assembly of small or large mitoribosomal subunits and the formation of the monosome by establishing quality-control checkpoints during these processes. Furthermore, following the recent unification of the nomenclature for the mitoribosomal proteins, we also propose a unified nomenclature for mitoribosome assembly GTPases.
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25
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Ferrari A, Del'Olio S, Barrientos A. The Diseased Mitoribosome. FEBS Lett 2020; 595:1025-1061. [PMID: 33314036 DOI: 10.1002/1873-3468.14024] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 12/17/2022]
Abstract
Mitochondria control life and death in eukaryotic cells. Harboring a unique circular genome, a by-product of an ancient endosymbiotic event, mitochondria maintains a specialized and evolutionary divergent protein synthesis machinery, the mitoribosome. Mitoribosome biogenesis depends on elements encoded in both the mitochondrial genome (the RNA components) and the nuclear genome (all ribosomal proteins and assembly factors). Recent cryo-EM structures of mammalian mitoribosomes have illuminated their composition and provided hints regarding their assembly and elusive mitochondrial translation mechanisms. A growing body of literature involves the mitoribosome in inherited primary mitochondrial disorders. Mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors impede mitoribosome biogenesis, causing protein synthesis defects that lead to respiratory chain failure and mitochondrial disorders such as encephalo- and cardiomyopathy, deafness, neuropathy, and developmental delays. In this article, we review the current fundamental understanding of mitoribosome assembly and function, and the clinical landscape of mitochondrial disorders driven by mutations in mitoribosome components and assembly factors, to portray how basic and clinical studies combined help us better understand both mitochondrial biology and medicine.
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Affiliation(s)
- Alberto Ferrari
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA
| | - Samuel Del'Olio
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA.,Molecular and Cellular Pharmacology Graduate Program, University of Miami Miller School of Medicine, FL, USA
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA.,Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, FL, USA
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26
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Metabolomics strategy assisted by transcriptomics analysis to identify biomarkers associated with schizophrenia. Anal Chim Acta 2020; 1140:18-29. [DOI: 10.1016/j.aca.2020.09.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/16/2020] [Accepted: 09/25/2020] [Indexed: 12/12/2022]
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27
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Abnormal Expression of Mitochondrial Ribosomal Proteins and Their Encoding Genes with Cell Apoptosis and Diseases. Int J Mol Sci 2020; 21:ijms21228879. [PMID: 33238645 PMCID: PMC7700125 DOI: 10.3390/ijms21228879] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/15/2020] [Accepted: 11/17/2020] [Indexed: 12/11/2022] Open
Abstract
Mammalian mitochondrial ribosomes translate 13 proteins encoded by mitochondrial genes, all of which play roles in the mitochondrial respiratory chain. After a long period of reconstruction, mitochondrial ribosomes are the most protein-rich ribosomes. Mitochondrial ribosomal proteins (MRPs) are encoded by nuclear genes, synthesized in the cytoplasm and then, transported to the mitochondria to be assembled into mitochondrial ribosomes. MRPs not only play a role in mitochondrial oxidative phosphorylation (OXPHOS). Moreover, they participate in the regulation of cell state as apoptosis inducing factors. Abnormal expressions of MRPs will lead to mitochondrial metabolism disorder, cell dysfunction, etc. Many researches have demonstrated the abnormal expression of MRPs in various tumors. This paper reviews the basic structure of mitochondrial ribosome, focuses on the structure and function of MRPs, and their relationships with cell apoptosis and diseases. It provides a reference for the study of the function of MRPs and the disease diagnosis and treatment.
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28
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Expression analysis of mammalian mitochondrial ribosomal protein genes. Gene Expr Patterns 2020; 38:119147. [PMID: 32987154 DOI: 10.1016/j.gep.2020.119147] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/14/2020] [Accepted: 09/20/2020] [Indexed: 02/07/2023]
Abstract
Mitochondrial ribosomal proteins (MRPs) are essential components for the structural and functional integrity of the mitoribosome complex. Throughout evolution, the mammalian mitoribosome has acquired new Mrp genes to compensate for loss of ribosomal RNA. More than 80 MRPs have been identified in mammals. Here we document expression pattern of 79 Mrp genes during mouse development and adult tissues and find that these genes are consistently expressed throughout early embryogenesis with little stage or tissue specificity. Further investigation of the amino acid sequence reveals that this group of proteins has little to no protein similarity. Recent work has shown that the majority of Mrp genes are essential resulting in early embryonic lethality, suggesting no functional redundancy among the group. Taken together, these results indicate that the Mrp genes are not a gene family descended from a single ancestral gene, and that each MRP has unique and essential role in the mitoribosome complex. The lack of functional redundancy is surprising given the importance of the mitoribosome for cellular and organismal viability. Further, these data suggest that genomic variants in Mrp genes may be causative for early pregnancy loss and should be evaluated as clinically.
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29
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Abstract
Mitochondrial disease presenting in childhood is characterized by clinical, biochemical and genetic complexity. Some children are affected by canonical syndromes, but the majority have nonclassical multisystemic disease presentations involving virtually any organ in the body. Each child has a unique constellation of clinical features and disease trajectory, leading to enormous challenges in diagnosis and management of these heterogeneous disorders. This review discusses the classical mitochondrial syndromes presenting most frequently in childhood and then presents an organ-based perspective including systems less frequently linked to mitochondrial disease, such as skin and hair abnormalities and immune dysfunction. An approach to diagnosis is then presented, encompassing clinical evaluation and biochemical, neuroimaging and genetic investigations, and emphasizing the problem of phenocopies. The impact of next-generation sequencing is discussed, together with the importance of functional validation of novel genetic variants never previously linked to mitochondrial disease. The review concludes with a brief discussion of currently available and emerging therapies. The field of mitochondrial medicine has made enormous strides in the last 30 years, with approaching 400 different genes across two genomes now linked to primary mitochondrial disease. However, many important questions remain unanswered, including the reasons for tissue specificity and variability of clinical presentation of individuals sharing identical gene defects, and a lack of disease-modifying therapies and biomarkers to monitor disease progression and/or response to treatment.
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Affiliation(s)
- S Rahman
- Mitochondrial Research Group, UCL Great Ormond Street Institute of Child Health, London, UK
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30
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Thompson K, Collier JJ, Glasgow RIC, Robertson FM, Pyle A, Blakely EL, Alston CL, Oláhová M, McFarland R, Taylor RW. Recent advances in understanding the molecular genetic basis of mitochondrial disease. J Inherit Metab Dis 2020; 43:36-50. [PMID: 31021000 PMCID: PMC7041634 DOI: 10.1002/jimd.12104] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/03/2019] [Accepted: 04/24/2019] [Indexed: 12/22/2022]
Abstract
Mitochondrial disease is hugely diverse with respect to associated clinical presentations and underlying genetic causes, with pathogenic variants in over 300 disease genes currently described. Approximately half of these have been discovered in the last decade due to the increasingly widespread application of next generation sequencing technologies, in particular unbiased, whole exome-and latterly, whole genome sequencing. These technologies allow more genetic data to be collected from patients with mitochondrial disorders, continually improving the diagnostic success rate in a clinical setting. Despite these significant advances, some patients still remain without a definitive genetic diagnosis. Large datasets containing many variants of unknown significance have become a major challenge with next generation sequencing strategies and these require significant functional validation to confirm pathogenicity. This interface between diagnostics and research is critical in continuing to expand the list of known pathogenic variants and concomitantly enhance our knowledge of mitochondrial biology. The increasing use of whole exome sequencing, whole genome sequencing and other "omics" techniques such as transcriptomics and proteomics will generate even more data and allow further interrogation and validation of genetic causes, including those outside of coding regions. This will improve diagnostic yields still further and emphasizes the integral role that functional assessment of variant causality plays in this process-the overarching focus of this review.
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Affiliation(s)
- Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Jack J. Collier
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Ruth I. C. Glasgow
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Fiona M. Robertson
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Angela Pyle
- Wellcome Centre for Mitochondrial Research, Institute of Genetic MedicineNewcastle UniversityNewcastle upon TyneUK
| | - Emma L. Blakely
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- NHS Highly Specialised Mitochondrial Diagnostic LaboratoryNewcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
| | - Charlotte L. Alston
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- NHS Highly Specialised Mitochondrial Diagnostic LaboratoryNewcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
| | - Monika Oláhová
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- NHS Highly Specialised Mitochondrial Diagnostic LaboratoryNewcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
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31
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Busch JD, Cipullo M, Atanassov I, Bratic A, Silva Ramos E, Schöndorf T, Li X, Pearce SF, Milenkovic D, Rorbach J, Larsson NG. MitoRibo-Tag Mice Provide a Tool for In Vivo Studies of Mitoribosome Composition. Cell Rep 2019; 29:1728-1738.e9. [PMID: 31693908 PMCID: PMC6859486 DOI: 10.1016/j.celrep.2019.09.080] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 08/14/2019] [Accepted: 09/26/2019] [Indexed: 11/16/2022] Open
Abstract
Mitochondria harbor specialized ribosomes (mitoribosomes) necessary for the synthesis of key membrane proteins of the oxidative phosphorylation (OXPHOS) machinery located in the mitochondrial inner membrane. To date, no animal model exists to study mitoribosome composition and mitochondrial translation coordination in mammals in vivo. Here, we create MitoRibo-Tag mice as a tool enabling affinity purification and proteomics analyses of mitoribosomes and their interactome in different tissues. We also define the composition of an assembly intermediate formed in the absence of MTERF4, necessary for a late step in mitoribosomal biogenesis. We identify the orphan protein PUSL1, which interacts with a large subunit assembly intermediate, and demonstrate that it is an inner-membrane-associated mitochondrial matrix protein required for efficient mitochondrial translation. This work establishes MitoRibo-Tag mice as a powerful tool to study mitoribosomes in vivo, enabling future studies on the mitoribosome interactome under different physiological states, as well as in disease and aging. MitoRibo-Tag mice with a tag on mL62 were generated to study mitoribosomes in vivo The mitoribosome interactome of different mouse tissues was defined with proteomics PUSL1 was identified as a mitoribosome-interacting protein using MitoRibo-Tag mice MitoRibo-Tag mice allow mitoribosome analysis under different conditions and setups
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Affiliation(s)
- Jakob D Busch
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany; Faculty of Mathematics and Natural Sciences, University of Cologne, Albertus-Magnus-Platz, 50923 Cologne, Germany
| | - Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Research Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden; Max-Planck-Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Ilian Atanassov
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Ana Bratic
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Eduardo Silva Ramos
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Thomas Schöndorf
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany; Faculty of Mathematics and Natural Sciences, University of Cologne, Albertus-Magnus-Platz, 50923 Cologne, Germany
| | - Xinping Li
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Sarah F Pearce
- Department of Medical Biochemistry and Biophysics, Research Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden; Max-Planck-Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Dusanka Milenkovic
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Research Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden; Max-Planck-Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
| | - Nils-Göran Larsson
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany; Department of Medical Biochemistry and Biophysics, Research Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden; Max-Planck-Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
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32
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Bugiardini E, Mitchell AL, Rosa ID, Horning-Do HT, Pitmann AM, Poole OV, Holton JL, Shah S, Woodward C, Hargreaves I, Quinlivan R, Amunts A, Wiesner RJ, Houlden H, Holt IJ, Hanna MG, Pitceathly RDS, Spinazzola A. MRPS25 mutations impair mitochondrial translation and cause encephalomyopathy. Hum Mol Genet 2019; 28:2711-2719. [PMID: 31039582 PMCID: PMC6687946 DOI: 10.1093/hmg/ddz093] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 04/25/2019] [Accepted: 04/25/2019] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial disorders are clinically and genetically heterogeneous and are associated with a variety of disease mechanisms. Defects of mitochondrial protein synthesis account for the largest subgroup of disorders manifesting with impaired respiratory chain capacity; yet, only a few have been linked to dysfunction in the protein components of the mitochondrial ribosomes. Here, we report a subject presenting with dyskinetic cerebral palsy and partial agenesis of the corpus callosum, while histochemical and biochemical analyses of skeletal muscle revealed signs of mitochondrial myopathy. Using exome sequencing, we identified a homozygous variant c.215C>T in MRPS25, which encodes for a structural component of the 28S small subunit of the mitochondrial ribosome (mS25). The variant segregated with the disease and substitutes a highly conserved proline residue with leucine (p.P72L) that, based on the high-resolution structure of the 28S ribosome, is predicted to compromise inter-protein contacts and destabilize the small subunit. Concordant with the in silico analysis, patient’s fibroblasts showed decreased levels of MRPS25 and other components of the 28S subunit. Moreover, assembled 28S subunits were scarce in the fibroblasts with mutant mS25 leading to impaired mitochondrial translation and decreased levels of multiple respiratory chain subunits. Crucially, these abnormalities were rescued by transgenic expression of wild-type MRPS25 in the mutant fibroblasts. Collectively, our data demonstrate the pathogenicity of the p.P72L variant and identify MRPS25 mutations as a new cause of mitochondrial translation defect.
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Affiliation(s)
- Enrico Bugiardini
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Alice L Mitchell
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London NW3 2PF, UK
| | - Ilaria Dalla Rosa
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London NW3 2PF, UK
| | - Hue-Tran Horning-Do
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Medical Faculty, University of Köln, 50931 Köln, Germany
| | - Alan M Pitmann
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Olivia V Poole
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Janice L Holton
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Sachit Shah
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Cathy Woodward
- Neurogenetic Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Iain Hargreaves
- Neurometabolic Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Rosaline Quinlivan
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165 Solna, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Medical Faculty, University of Köln, 50931 Köln, Germany
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Ian J Holt
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London NW3 2PF, UK
- Biodonostia Health Research Institute, 20014 San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
- CIBERNED (Center for Networked Biomedical Research on Neurodegenerative Diseases, Ministry of Economy and Competitiveness, Institute Carlos III), Madrid, Spain
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Robert D S Pitceathly
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Antonella Spinazzola
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London NW3 2PF, UK
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