1
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Krieger MR, Abrahamian M, He KL, Atamdede S, Hakimjavadi H, Momcilovic M, Ostrow D, Maggo SD, Tsang YP, Gai X, Chanfreau GF, Shackelford DB, Teitell MA, Koehler CM. Trafficking of mitochondrial double-stranded RNA from mitochondria to the cytosol. Life Sci Alliance 2024; 7:e202302396. [PMID: 38955468 PMCID: PMC11220484 DOI: 10.26508/lsa.202302396] [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: 09/26/2023] [Revised: 06/25/2024] [Accepted: 06/25/2024] [Indexed: 07/04/2024] Open
Abstract
In addition to mitochondrial DNA, mitochondrial double-stranded RNA (mtdsRNA) is exported from mitochondria. However, specific channels for RNA transport have not been demonstrated. Here, we begin to characterize channel candidates for mtdsRNA export from the mitochondrial matrix to the cytosol. Down-regulation of SUV3 resulted in the accumulation of mtdsRNAs in the matrix, whereas down-regulation of PNPase resulted in the export of mtdsRNAs to the cytosol. Targeting experiments show that PNPase functions in both the intermembrane space and matrix. Strand-specific sequencing of the double-stranded RNA confirms the mitochondrial origin. Inhibiting or down-regulating outer membrane proteins VDAC1/2 and BAK/BAX or inner membrane proteins PHB1/2 strongly attenuated the export of mtdsRNAs to the cytosol. The cytosolic mtdsRNAs subsequently localized to large granules containing the stress protein TIA-1 and activated the type 1 interferon stress response pathway. Abundant mtdsRNAs were detected in a subset of non-small-cell lung cancer cell lines that were glycolytic, indicating relevance in cancer biology. Thus, we propose that mtdsRNA is a new damage-associated molecular pattern that is exported from mitochondria in a regulated manner.
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Affiliation(s)
- Matthew R Krieger
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, USA
| | | | - Kevin L He
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, USA
| | - Sean Atamdede
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, USA
| | | | - Milica Momcilovic
- Pulmonary and Critical Care Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, USA
| | - Dejerianne Ostrow
- Department of Pathology, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Simran Ds Maggo
- Department of Pathology, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Yik Pui Tsang
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, USA
| | - Xiaowu Gai
- Department of Pathology, Children's Hospital Los Angeles, Los Angeles, CA, USA
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Guillaume F Chanfreau
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, USA
- Molecular Biology Institute, UCLA, Los Angeles, CA, USA
| | - David B Shackelford
- Pulmonary and Critical Care Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, USA
| | - Michael A Teitell
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, USA
- Molecular Biology Institute, UCLA, Los Angeles, CA, USA
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, CA, USA
- Broad Stem Cell Research Center, UCLA, Los Angeles, CA, USA
- NanoSystems Institute, UCLA, Los Angeles, CA, USA
| | - Carla M Koehler
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, USA
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, USA
- Molecular Biology Institute, UCLA, Los Angeles, CA, USA
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2
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Idiiatullina E, Al-Azab M, Lin M, Hrovat-Schaale K, Liu Z, Li X, Guo C, Chen X, Li Y, Gao S, Cui J, Zhou W, Liu L, Zhang Y, Masters SL. Heterozygous de novo dominant negative mutation of REXO2 results in interferonopathy. Nat Commun 2024; 15:6685. [PMID: 39107301 PMCID: PMC11303720 DOI: 10.1038/s41467-024-50878-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 07/22/2024] [Indexed: 08/10/2024] Open
Abstract
Mitochondrial RNA (mtRNA) in the cytosol can trigger the innate immune sensor MDA5, and autoinflammatory disease due to type I IFN. Here, we show that a dominant negative mutation in the gene encoding the mitochondrial exonuclease REXO2 may cause interferonopathy by triggering the MDA5 pathway. A patient characterized by this heterozygous de novo mutation (p.T132A) presented with persistent skin rash featuring hyperkeratosis, parakeratosis and acanthosis, with infiltration of lymphocytes and eosinophils around small blood vessels. In addition, circulating IgE levels and inflammatory cytokines, including IFNα, are found consistently elevated. Transcriptional analysis highlights a type I IFN gene signature in PBMC. Mechanistically, REXO2 (T132A) lacks the ability to cleave RNA and inhibits the activity of wild-type REXO2. This leads to an accumulation of mitochondrial dsRNA in the cytosol, which is recognized by MDA5, leading to the associated type I IFN gene signature. These results demonstrate that in the absence of appropriate regulation by REXO2, aberrant cellular nucleic acids may accumulate and continuously trigger innate sensors, resulting in an inborn error of immunity.
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Affiliation(s)
- Elina Idiiatullina
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
- Department of Therapy and Nursing, Bashkir State Medical University, Ufa, Russia
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, USA
| | - Mahmoud Al-Azab
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
- Department of Medical Microbiology, Faculty of Medicine, University of Science and Technology, Aden, Yemen
| | - Meng Lin
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
| | - Katja Hrovat-Schaale
- Department of Therapy and Nursing, Bashkir State Medical University, Ufa, Russia
- Department of Medical Microbiology, Faculty of Medicine, University of Science and Technology, Aden, Yemen
| | - Ziyang Liu
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
| | - Xiaotian Li
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
| | - Caiqin Guo
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
| | - Xixi Chen
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
| | - Yaoying Li
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Song Gao
- State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Jun Cui
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wenhao Zhou
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
| | - Li Liu
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China.
| | - Yuxia Zhang
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China.
| | - Seth L Masters
- Department of Genetics and Endocrinology, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China.
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.
- Department of Medical Biology, The University of Melbourne, Parkville, Australia.
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.
- Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia.
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3
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Nikitchina N, Ulashchik E, Shmanai V, Heckel AM, Tarassov I, Mazunin I, Entelis N. Targeting of CRISPR-Cas12a crRNAs into human mitochondria. Biochimie 2024; 217:74-85. [PMID: 37690471 DOI: 10.1016/j.biochi.2023.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/10/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023]
Abstract
Mitochondrial gene editing holds great promise as a therapeutic approach for mitochondrial diseases caused by mutations in the mitochondrial DNA (mtDNA). Current strategies focus on reducing mutant mtDNA heteroplasmy levels through targeted cleavage or base editing. However, the delivery of editing components into mitochondria remains a challenge. Here we investigate the import of CRISPR-Cas12a system guide RNAs (crRNAs) into human mitochondria and study the structural requirements for this process by northern blot analysis of RNA isolated from nucleases-treated mitoplasts. To investigate whether the fusion of crRNA with known RNA import determinants (MLS) improve its mitochondrial targeting, we added MLS hairpin structures at 3'-end of crRNA and demonstrated that this did not impact crRNA ability to program specific cleavage of DNA in lysate of human cells expressing AsCas12a nuclease. Surprisingly, mitochondrial localization of the fused crRNA molecules was not improved compared to non-modified version, indicating that structured scaffold domain of crRNA can probably function as MLS, assuring crRNA mitochondrial import. Then, we designed a series of crRNAs targeting different regions of mtDNA and demonstrated their ability to program specific cleavage of mtDNA fragments in cell lysate and their partial localization in mitochondrial matrix in human cells transfected with these RNA molecules. We hypothesize that mitochondrial import of crRNAs may depend on their secondary structure/sequence. We presume that imported crRNA allow reconstituting the active crRNA/Cas12a system in human mitochondria, which can contribute to the development of effective strategies for mitochondrial gene editing and potential future treatment of mitochondrial diseases.
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Affiliation(s)
- Natalia Nikitchina
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, Strasbourg, 67000, France
| | - Egor Ulashchik
- Institute of Physical Organic Chemistry, National Academy of Science of Belarus, Minsk, 220072, Belarus
| | - Vadim Shmanai
- Institute of Physical Organic Chemistry, National Academy of Science of Belarus, Minsk, 220072, Belarus
| | - Anne-Marie Heckel
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, Strasbourg, 67000, France
| | - Ivan Tarassov
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, Strasbourg, 67000, France
| | - Ilya Mazunin
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow, 143026, Russia
| | - Nina Entelis
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, Strasbourg, 67000, France.
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4
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Chen PL. SUV3 Helicase and Mitochondrial Homeostasis. Int J Mol Sci 2023; 24:9233. [PMID: 37298184 PMCID: PMC10253155 DOI: 10.3390/ijms24119233] [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: 04/25/2023] [Revised: 05/21/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
SUV3 is a nuclear-encoded helicase that is highly conserved and localizes to the mitochondrial matrix. In yeast, loss of SUV3 function leads to the accumulation of group 1 intron transcripts, ultimately resulting in the loss of mitochondrial DNA, causing a petite phenotype. However, the mechanism leading to the loss of mitochondrial DNA remains unknown. SUV3 is essential for survival in higher eukaryotes, and its knockout in mice results in early embryonic lethality. Heterozygous mice exhibit a range of phenotypes, including premature aging and an increased cancer incidence. Furthermore, cells derived from SUV3 heterozygotes or knockdown cultural cells show a reduction in mtDNA. Transient downregulation of SUV3 leads to the formation of R-loops and the accumulation of double-stranded RNA in mitochondria. This review aims to provide an overview of the current knowledge regarding the SUV3-containing complex and discuss its potential mechanism for tumor suppression activity.
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Affiliation(s)
- Phang-Lang Chen
- Department of Biological Chemistry, University of California, Irvine, CA 92697, USA
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5
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Straub S, Sampaio NG. Activation of cytosolic RNA sensors by endogenous ligands: roles in disease pathogenesis. Front Immunol 2023; 14:1092790. [PMID: 37292201 PMCID: PMC10244536 DOI: 10.3389/fimmu.2023.1092790] [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: 11/08/2022] [Accepted: 05/15/2023] [Indexed: 06/10/2023] Open
Abstract
Early detection of infection is a central and critical component of our innate immune system. Mammalian cells have developed specialized receptors that detect RNA with unusual structures or of foreign origin - a hallmark of many virus infections. Activation of these receptors induces inflammatory responses and an antiviral state. However, it is increasingly appreciated that these RNA sensors can also be activated in the absence of infection, and that this 'self-activation' can be pathogenic and promote disease. Here, we review recent discoveries in sterile activation of the cytosolic innate immune receptors that bind RNA. We focus on new aspects of endogenous ligand recognition uncovered in these studies, and their roles in disease pathogenesis.
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Affiliation(s)
- Sarah Straub
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
| | - Natalia G. Sampaio
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash University, Clayton, VIC, Australia
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6
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Mitochondrial Dysfunction and Oxidative Stress in Hereditary Ectopic Calcification Diseases. Int J Mol Sci 2022; 23:ijms232315288. [PMID: 36499615 PMCID: PMC9738718 DOI: 10.3390/ijms232315288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 11/26/2022] [Accepted: 12/01/2022] [Indexed: 12/08/2022] Open
Abstract
Ectopic calcification (EC) is characterized by an abnormal deposition of calcium phosphate crystals in soft tissues such as blood vessels, skin, and brain parenchyma. EC contributes to significant morbidity and mortality and is considered a major health problem for which no effective treatments currently exist. In recent years, growing emphasis has been placed on the role of mitochondrial dysfunction and oxidative stress in the pathogenesis of EC. Impaired mitochondrial respiration and increased levels of reactive oxygen species can be directly linked to key molecular pathways involved in EC such as adenosine triphosphate homeostasis, DNA damage signaling, and apoptosis. While EC is mainly encountered in common diseases such as diabetes mellitus and chronic kidney disease, studies in rare hereditary EC disorders such as pseudoxanthoma elasticum or Hutchinson-Gilford progeria syndrome have been instrumental in identifying the precise etiopathogenetic mechanisms leading to EC. In this narrative review, we describe the current state of the art regarding the role of mitochondrial dysfunction and oxidative stress in hereditary EC diseases. In-depth knowledge of aberrant mitochondrial metabolism and its local and systemic consequences will benefit the research into novel therapies for both rare and common EC disorders.
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7
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Ventura I, Revert F, Revert-Ros F, Gómez-Tatay L, Prieto-Ruiz JA, Hernández-Andreu JM. SP1 and NFY Regulate the Expression of PNPT1, a Gene Encoding a Mitochondrial Protein Involved in Cancer. Int J Mol Sci 2022; 23:ijms231911399. [PMID: 36232701 PMCID: PMC9570217 DOI: 10.3390/ijms231911399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/13/2022] [Accepted: 09/23/2022] [Indexed: 11/26/2022] Open
Abstract
The Polyribonucleotide nucleotidyltransferase 1 gene (PNPT1) encodes polynucleotide phosphorylase (PNPase), a 3′-5′ exoribonuclease involved in mitochondrial RNA degradation and surveillance and RNA import into the mitochondrion. Here, we have characterized the PNPT1 promoter by in silico analysis, luciferase reporter assays, electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation (ChIP), siRNA-based mRNA silencing and RT-qPCR. We show that the Specificity protein 1 (SP1) transcription factor and Nuclear transcription factor Y (NFY) bind the PNPT1 promoter, and have a relevant role regulating the promoter activity, PNPT1 expression, and mitochondrial activity. We also found in Kaplan–Meier survival curves that a high expression of either PNPase, SP1 or NFY subunit A (NFYA) is associated with a poor prognosis in liver cancer. In summary, our results show the relevance of SP1 and NFY in PNPT1 expression, and point to SP1/NFY and PNPase as possible targets in anti-cancer therapy.
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8
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Barbier M, Bahlo M, Pennisi A, Jacoupy M, Tankard RM, Ewenczyk C, Davies KC, Lino-Coulon P, Colace C, Rafehi H, Auger N, Ansell BRE, van der Stelt I, Howell KB, Coutelier M, Amor DJ, Mundwiller E, Guillot-Noël L, Storey E, Gardner RJM, Wallis MJ, Brusco A, Corti O, Rötig A, Leventer RJ, Brice A, Delatycki MB, Stevanin G, Lockhart PJ, Durr A. Heterozygous PNPT1 variants cause spinocerebellar ataxia type 25. Ann Neurol 2022; 92:122-137. [PMID: 35411967 DOI: 10.1002/ana.26366] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 04/04/2022] [Accepted: 04/08/2022] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Dominant spinocerebellar ataxias (SCA) are characterized by genetic heterogeneity. Some mapped and named loci remain without a causal gene identified. Here we applied next generation sequencing (NGS) to uncover the genetic etiology of the SCA25 locus. METHODS Whole-exome and whole-genome sequencing were performed in families linked to SCA25, including the French family in which the SCA25 locus was originally mapped. Whole exome sequence data was interrogated in a cohort of 796 ataxia patients of unknown aetiology. RESULTS The SCA25 phenotype spans a slowly evolving sensory and cerebellar ataxia, in most cases attributed to ganglionopathy. A pathogenic variant causing exon skipping was identified in the gene encoding Polyribonucleotide Nucleotidyltransferase PNPase 1 (PNPT1) located in the SCA25 linkage interval. A second splice variant in PNPT1 was detected in a large Australian family with a dominant ataxia also mapping to SCA25. An additional nonsense variant was detected in an unrelated individual with ataxia. Both nonsense and splice heterozygous variants result in premature stop codons, all located in the S1-domain of PNPase. In addition, an elevated type I interferon response was observed in blood from all affected heterozygous carriers tested. PNPase notably prevents the abnormal accumulation of double-stranded mtRNAs in the mitochondria and leakage into the cytoplasm, associated with triggering a type I interferon response. INTERPRETATION This study identifies PNPT1 as a new SCA gene, responsible for SCA25, and highlights biological links between alterations of mtRNA trafficking, interferonopathies and ataxia. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mathieu Barbier
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Alessandra Pennisi
- Necker Hospital, APHP, Reference Center for Mitochondrial Diseases, Genetics Department, Institut Imagine, University of Paris, Paris, France.,Inserm UMR_S1163, Institut Imagine, Paris, France
| | - Maxime Jacoupy
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Rick M Tankard
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Claire Ewenczyk
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Kayli C Davies
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Melbourne, Victoria, 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Patricia Lino-Coulon
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Claire Colace
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Haloom Rafehi
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Nicolas Auger
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France.,Paris Sciences Lettres Research University, EPHE, Paris, France
| | - Brendan R E Ansell
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Ivo van der Stelt
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Victoria, 3010, Australia.,Donders Centre for Neuroscience, Faculty of Science, Radboud University, The Netherlands
| | - Katherine B Howell
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, 3010, Australia.,Department of Neurology, Royal Children's Hospital, Melbourne, Victoria, 3052, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, 3052, Australia
| | - Marie Coutelier
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France.,Paris Sciences Lettres Research University, EPHE, Paris, France
| | - David J Amor
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, 3010, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, 3052, Australia
| | - Emeline Mundwiller
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Lena Guillot-Noël
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France.,Paris Sciences Lettres Research University, EPHE, Paris, France
| | - Elsdon Storey
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, 3004, Australia
| | | | - Mathew J Wallis
- Clinical Genetics Service, Austin Health, Melbourne, Australia; Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia.,School of Medicine and Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Olga Corti
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Agnès Rötig
- Necker Hospital, APHP, Reference Center for Mitochondrial Diseases, Genetics Department, Institut Imagine, University of Paris, Paris, France.,Inserm UMR_S1163, Institut Imagine, Paris, France
| | - Richard J Leventer
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, 3010, Australia.,Department of Neurology, Royal Children's Hospital, Melbourne, Victoria, 3052, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, 3052, Australia
| | - Alexis Brice
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Martin B Delatycki
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Melbourne, Victoria, 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, 3010, Australia.,Victorian Clinical Genetics Service, Melbourne, 3052, Australia
| | - Giovanni Stevanin
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France.,Paris Sciences Lettres Research University, EPHE, Paris, France
| | - Paul J Lockhart
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Melbourne, Victoria, 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Alexandra Durr
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
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9
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Falchi FA, Pizzoccheri R, Briani F. Activity and Function in Human Cells of the Evolutionary Conserved Exonuclease Polynucleotide Phosphorylase. Int J Mol Sci 2022; 23:ijms23031652. [PMID: 35163574 PMCID: PMC8836086 DOI: 10.3390/ijms23031652] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 02/04/2023] Open
Abstract
Polynucleotide phosphorylase (PNPase) is a phosphorolytic RNA exonuclease highly conserved throughout evolution. Human PNPase (hPNPase) is located in mitochondria and is essential for mitochondrial function and homeostasis. Not surprisingly, mutations in the PNPT1 gene, encoding hPNPase, cause serious diseases. hPNPase has been implicated in a plethora of processes taking place in different cell compartments and involving other proteins, some of which physically interact with hPNPase. This paper reviews hPNPase RNA binding and catalytic activity in relation with the protein structure and in comparison, with the activity of bacterial PNPases. The functions ascribed to hPNPase in different cell compartments are discussed, highlighting the gaps that still need to be filled to understand the physiological role of this ancient protein in human cells.
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10
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Nahálková J. Focus on Molecular Functions of Anti-Aging Deacetylase SIRT3. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:21-34. [PMID: 35491023 DOI: 10.1134/s0006297922010035] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
SIRT3 is a protein lysine deacetylase with a prominent role in the maintenance of mitochondrial integrity, which is a vulnerable target in many diseases. Intriguingly, cellular aging is reversible just by SIRT3 overexpression, which raises many questions about the role of SIRT3 in the molecular anti-aging mechanisms. Therefore, functions of SIRT3 were analyzed through the interaction network of 407 substrates collected by data mining. Results of the pathway enrichment and gene function prediction confirmed functions in the primary metabolism and mitochondrial ATP production. However, it also suggested involvement in thermogenesis, brain-related neurodegenerative diseases Alzheimer's (AD), Parkinson's, Huntington's disease (HD), and non-alcoholic fatty liver disease. The protein node prioritization analysis identified subunits of the complex I of the mitochondrial respiratory chain (MRC) as the nodes with the main regulatory effect within the entire interaction network. Additional high-ranked nodes were succinate dehydrogenase subunit B (SDHB), complex II, and ATP5F1, complex V of MRC. The analysis supports existence of the NADH/NAD+ driven regulatory feedback loop between SIRT3, complex I (MRC), and acetyl-CoA synthetases, and existence of the nuclear substrates of SIRT3. Unexplored functions of SIRT3 substrates such as LMNA and LMNB; HIF-1a, p53, DNA-PK, and PARK7 are highlighted for further scientific advances. SIRT3 acts as a repressor of BACE1 through the SIRT3-LKB1-AMPK-CREB-PGC1A-PPARG-BACE1 (SIRT3-BACE1), which functions are fitted the best by the Circadian Clock pathway. It forms a new working hypothesis as the therapeutical target for AD treatment. Other important pathways linked to SIRT3 activity are highlighted for therapeutical interventions.
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Affiliation(s)
- Jarmila Nahálková
- Biochemistry, Molecular, and Cell Biology Unit, Biochemworld Co., Skyttorp, Uppsala County, 74394, Sweden.
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11
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Benjamin P, Sudhakar S, D’Arco F, Löbel U, Carney O, Roux CJ, Boddaert N, Hemingway C, Eleftheriou D, Mankad K. Spectrum of Neuroradiologic Findings Associated with Monogenic Interferonopathies. AJNR Am J Neuroradiol 2022; 43:2-10. [PMID: 34949589 PMCID: PMC8757560 DOI: 10.3174/ajnr.a7362] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/29/2021] [Indexed: 01/03/2023]
Abstract
The genetic interferonopathies are a heterogeneous group of disorders thought to be caused by the dysregulated expression of interferons and are now commonly considered in the differential diagnosis of children presenting with recurrent or persistent inflammatory phenotypes. With emerging therapeutic options, recognition of these disorders is increasingly important, and neuroimaging plays a vital role. In this article, we discuss the wide spectrum of neuroradiologic features associated with monogenic interferonopathies by reviewing the literature and illustrate these with cases from our institutions. These cases include intracerebral calcifications, white matter T2 hyperintensities, deep WM cysts, cerebral atrophy, large cerebral artery disease, bilateral striatal necrosis, and masslike lesions. A better understanding of the breadth of the neuroimaging phenotypes in conjunction with clinical and laboratory findings will enable earlier diagnosis and direct therapeutic strategies.
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Affiliation(s)
- P. Benjamin
- From the Department of Radiology (P.B., S.S., F.D., U.L., O.C., K.M.), Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - S. Sudhakar
- From the Department of Radiology (P.B., S.S., F.D., U.L., O.C., K.M.), Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - F. D’Arco
- From the Department of Radiology (P.B., S.S., F.D., U.L., O.C., K.M.), Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - U. Löbel
- From the Department of Radiology (P.B., S.S., F.D., U.L., O.C., K.M.), Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - O. Carney
- From the Department of Radiology (P.B., S.S., F.D., U.L., O.C., K.M.), Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - C.-J. Roux
- Department of Paediatric Radiology (C.-J.R., N.B.), Hôpital Necker–Enfants Malades, Paris, France
| | - N. Boddaert
- Department of Paediatric Radiology (C.-J.R., N.B.), Hôpital Necker–Enfants Malades, Paris, France,Institut Imagine (N.B.), Institut National de la Santé et de la Recherche Médicale Union Mutualiste Retraite 1163, Paris, France
| | - C. Hemingway
- Department of Paediatric Neurology (C.H.), Great Ormond Street Hospital, London, UK
| | - D. Eleftheriou
- Infection, Inflammation, and Immunology Section (D.E.), University College London Great Ormond Street Institute of Child Health, London, UK
| | - K. Mankad
- From the Department of Radiology (P.B., S.S., F.D., U.L., O.C., K.M.), Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
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12
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Grochowska J, Czerwinska J, Borowski LS, Szczesny RJ. Mitochondrial RNA, a new trigger of the innate immune system. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1690. [PMID: 34498404 DOI: 10.1002/wrna.1690] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 02/06/2023]
Abstract
Mitochondria play a pivotal role in numerous cellular processes. One of them is regulation of the innate immune pathway. In this instance, mitochondria function in two different aspects of regulatory mechanisms. First, mitochondria are part of the antiviral signaling cascade that is triggered in the cytoplasm and transmitted to effector proteins through mitochondria-localized proteins. Second, mitochondria can become an endogenous source of innate immune stimuli. Under some pathophysiological conditions, mitochondria release to the cytoplasm immunogenic factors, such as mitochondrial nucleic acids. Here, we focus on immunogenic mitochondrial double-stranded RNA (mt-dsRNA) and its origin and metabolism. We discuss factors that are responsible for regulating mt-dsRNA and its escape from mitochondria, emphasizing the contribution of polynucleotide phosphorylase (PNPase, PNPT1). Finally, we review current knowledge of the role of PNPase in human health and disease. This article is categorized under: RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Joanna Grochowska
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland
| | - Jolanta Czerwinska
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland
| | - Lukasz S Borowski
- Faculty of Biology, Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland
| | - Roman J Szczesny
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Warsaw, Poland
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Abstract
Mitochondria are organelles with vital functions in almost all eukaryotic cells. Often described as the cellular 'powerhouses' due to their essential role in aerobic oxidative phosphorylation, mitochondria perform many other essential functions beyond energy production. As signaling organelles, mitochondria communicate with the nucleus and other organelles to help maintain cellular homeostasis, allow cellular adaptation to diverse stresses, and help steer cell fate decisions during development. Mitochondria have taken center stage in the research of normal and pathological processes, including normal tissue homeostasis and metabolism, neurodegeneration, immunity and infectious diseases. The central role that mitochondria assume within cells is evidenced by the broad impact of mitochondrial diseases, caused by defects in either mitochondrial or nuclear genes encoding for mitochondrial proteins, on different organ systems. In this Review, we will provide the reader with a foundation of the mitochondrial 'hardware', the mitochondrion itself, with its specific dynamics, quality control mechanisms and cross-organelle communication, including its roles as a driver of an innate immune response, all with a focus on development, disease and aging. We will further discuss how mitochondrial DNA is inherited, how its mutation affects cell and organismal fitness, and current therapeutic approaches for mitochondrial diseases in both model organisms and humans.
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Affiliation(s)
- Marlies P. Rossmann
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Sonia M. Dubois
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Suneet Agarwal
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Leonard I. Zon
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115, USA
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Hosseini Bereshneh A, Rezaei Z, Jafarinia E, Rajabi F, Ashrafi MR, Tavasoli AR, Garshasbi M. Crystallographic modeling of the PNPT1:c.1453A>G variant as a cause of mitochondrial dysfunction and autosomal recessive deafness; expanding the neuroimaging and clinical features. Mitochondrion 2021; 59:1-7. [PMID: 33812062 DOI: 10.1016/j.mito.2021.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/21/2022]
Abstract
Deficiency of the proteins involved in oxidative phosphorylation (OXPHOS) can lead to mitochondrial dysfunction. Polyribonucleotide nucleotidyltransferase 1 (PNPT1) is one of the genes involved in the OXPHOS and encodes the mitochondrial polynucleotide phosphorylase (PNPase) which is implicated in RNA-processing exoribonuclease activity. Herein, we report a 34-month-old boy who presented with global developmental delay, muscular hypotonia, hearing impairment, and movement disorders including chorea and dystonia. Mitochondrial genome sequencing and whole-exome sequencing (WES) were performed and a variant in PNPT1:c.1453A>G; p. (Met485Val) was identified. A number of patient's neurologic problems had been already reported in previous studies, however, lower limbs spasticity and bulbar dysfunction were novel phenotypic findings. In addition, delayed myelination during infancy, progressive basal ganglia atrophy, and brain stem abnormal signals including transverse pontine fibers and superior colliculus involvement were also novel neuroimaging findings in this case. Different crystallographic modeling and stereochemical analysis of the c.1453A>G; p. (Met485Val) variant showed this variant affects the active site of the protein and disrupts the normal protein function.
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Affiliation(s)
- Ali Hosseini Bereshneh
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Department of Medical Genetics, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran; Prenatal Diagnosis and Genetic Research Center, Dastgheib Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Rezaei
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Ehsan Jafarinia
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Fatemeh Rajabi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mahmoud Reza Ashrafi
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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15
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Bamborschke D, Kreutzer M, Koy A, Koerber F, Lucas N, Huenseler C, Herkenrath P, Lee-Kirsch MA, Cirak S. PNPT1 mutations may cause Aicardi-Goutières-Syndrome. Brain Dev 2021; 43:320-324. [PMID: 33158637 DOI: 10.1016/j.braindev.2020.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Aicardi-Goutières syndrome (AGS) is a clinically and genetically heterogenous autoinflammatory disorder caused by constitutive activation of the type I interferon axis. It has been associated with the genes TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR1, IFIH1. The clinical diagnosis of AGS is usually made in the context of early-onset encephalopathy in combination with basal ganglia calcification or white matter abnormalities on cranial MRI and laboratory prove of interferon I activation. CASE PRESENTATION We report a patient with early-onset encephalopathy, severe neurodevelopmental regression, progressive secondary microcephaly, epilepsy, movement disorder, and white matter hyperintensities on T2 weighted MRI images. Via whole-exome sequencing, we identified a novel homozygous missense variant (c.1399C > T, p.Pro467Ser) in PNPT1 (NM_033109). Longitudinal assessment of the interferon signature showed a massively elevated interferon score and chronic type I interferon-mediated autoinflammation. CONCLUSION Bi-allelic mutations in PNPT1 have been reported in early-onset encephalopathy. Insufficient nuclear RNA import into mitochondria with consecutive disruption of the respiratory chain was proposed as the main underlying pathomechanism. Recent studies have shown that PNPT1 deficiency causes an accumulation of double-stranded mtRNAs in the cytoplasm, leading to aberrant type I interferon activation, however, longitudinal assessment has been lacking. Here, we present a case of AGS with continuously elevated type I interferon signature with a novel likely-pathogenic homozygous PNTP1 variant. We highlight the clinical value of assessing the interferon signature in children with encephalopathy of unknown origin and suggest all patients presenting with a phenotype of AGS should be screened for mutations in PNPT1.
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Affiliation(s)
- Daniel Bamborschke
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Mona Kreutzer
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Anne Koy
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Friederike Koerber
- Department of Pediatric Radiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Nadja Lucas
- Department of Pediatrics, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Christoph Huenseler
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Peter Herkenrath
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Min Ae Lee-Kirsch
- Department of Pediatrics, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Sebahattin Cirak
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
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16
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Pennisi A, Rötig A, Roux CJ, Lévy R, Henneke M, Gärtner J, Teke Kisa P, Sarioglu FC, Yiş U, Konczal LL, Burkardt DD, Wu S, Gaignard P, Besmond C, Hubert L, Rio M, Barcia G, Munnich A, Boddaert N, Schiff M. Heterogeneity of PNPT1 neuroimaging: mitochondriopathy, interferonopathy or both? J Med Genet 2020; 59:204-208. [PMID: 33199448 DOI: 10.1136/jmedgenet-2020-107367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/01/2020] [Accepted: 10/24/2020] [Indexed: 01/31/2023]
Abstract
BACKGROUND Biallelic variants in PNPT1 cause a mitochondrial disease of variable severity. PNPT1 (polynucleotide phosphorylase) is a mitochondrial protein involved in RNA processing where it has a dual role in the import of small RNAs into mitochondria and in preventing the formation and release of mitochondrial double-stranded RNA into the cytoplasm. This, in turn, prevents the activation of type I interferon response. Detailed neuroimaging findings in PNPT1-related disease are lacking with only a few patients reported with basal ganglia lesions (Leigh syndrome) or non-specific signs. OBJECTIVE AND METHODS To document neuroimaging data in six patients with PNPT1 highlighting novel findings. RESULTS Two patients exhibited striatal lesions compatible with Leigh syndrome; one patient exhibited leukoencephalopathy and one patient had a normal brain MRI. Interestingly, two unrelated patients exhibited cystic leukoencephalopathy resembling RNASET2-deficient patients, patients with Aicardi-Goutières syndrome (AGS) or congenital CMV infection. CONCLUSION We suggest that similar to RNASET2, PNPT1 be searched for in the setting of cystic leukoencephalopathy. These findings are in line with activation of type I interferon response observed in AGS, PNPT1 and RNASET2 deficiencies, suggesting a common pathophysiological pathway and linking mitochondrial diseases, interferonopathies and immune dysregulations.
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Affiliation(s)
- Alessandra Pennisi
- Necker Hospital, APHP, Reference Center for Mitochondrial Diseases, Genetics Department, Institut Imagine, University of Paris, Paris, France
- Inserm UMR_S1163, Institut Imagine, Paris, France
| | - Agnès Rötig
- Necker Hospital, APHP, Reference Center for Mitochondrial Diseases, Genetics Department, Institut Imagine, University of Paris, Paris, France
- Inserm UMR_S1163, Institut Imagine, Paris, France
| | - Charles-Joris Roux
- Necker Hospital, APHP, Pediatric Radiology Department, University of Paris, Paris, France
| | - Raphaël Lévy
- Necker Hospital, APHP, Pediatric Radiology Department, University of Paris, Paris, France
| | - Marco Henneke
- Department of Paediatrics and Adolescent Medicine, Germany, University Medical Centre Göttingen, Georg August University Göttingen, Göttingen, Germany
| | - Jutta Gärtner
- Department of Paediatrics and Adolescent Medicine, Germany, University Medical Centre Göttingen, Georg August University Göttingen, Göttingen, Germany
| | - Pelin Teke Kisa
- Pediatric Metabolism and Nutrition, Dokuz Eylül University, Izmir, Turkey
| | | | - Uluç Yiş
- Pediatric Neurology, Dokuz Eylül University, Izmir, Turkey
| | - Laura L Konczal
- Center for Human Genetics, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Department of Genetics, Case Western Reserve University, Cleveland, OH, USA
| | - Deepika D Burkardt
- Center for Human Genetics, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
- Department of Genetics, Case Western Reserve University, Cleveland, OH, USA
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sulin Wu
- Department of Genetics, Case Western Reserve University, Cleveland, OH, USA
- Department of Internal Medicine, University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | - Pauline Gaignard
- Bicêtre Hospital, APHP, Department of Biochemistry, Bicêtre, France
| | | | | | - Marlène Rio
- Necker Hospital, APHP, Reference Center for Mitochondrial Diseases, Genetics Department, Institut Imagine, University of Paris, Paris, France
| | - Giulia Barcia
- Necker Hospital, APHP, Reference Center for Mitochondrial Diseases, Genetics Department, Institut Imagine, University of Paris, Paris, France
| | - Arnold Munnich
- Necker Hospital, APHP, Reference Center for Mitochondrial Diseases, Genetics Department, Institut Imagine, University of Paris, Paris, France
- Inserm UMR_S1163, Institut Imagine, Paris, France
| | - Nathalie Boddaert
- Inserm UMR_S1163, Institut Imagine, Paris, France
- Necker Hospital, APHP, Pediatric Radiology Department, University of Paris, Paris, France
| | - Manuel Schiff
- Necker Hospital, APHP, Reference Center for Mitochondrial Diseases, Genetics Department, Institut Imagine, University of Paris, Paris, France
- Inserm UMR_S1163, Institut Imagine, Paris, France
- Necker Hospital, APHP, Reference Center for Inborn Errors of Metabolism, Institut Imagine, University of Paris, Paris, France
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17
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Muthunayake NS, Tomares DT, Childers WS, Schrader JM. Phase-separated bacterial ribonucleoprotein bodies organize mRNA decay. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1599. [PMID: 32445438 PMCID: PMC7554086 DOI: 10.1002/wrna.1599] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 01/12/2023]
Abstract
In bacteria, mRNA decay is controlled by megadalton scale macromolecular assemblies called, "RNA degradosomes," composed of nucleases and other RNA decay associated proteins. Recent advances in bacterial cell biology have shown that RNA degradosomes can assemble into phase-separated structures, termed bacterial ribonucleoprotein bodies (BR-bodies), with many analogous properties to eukaryotic processing bodies and stress granules. This review will highlight the functional role that BR-bodies play in the mRNA decay process through its organization into a membraneless organelle in the bacterial cytoplasm. This review will also highlight the phylogenetic distribution of BR-bodies across bacterial species, which suggests that these phase-separated structures are broadly distributed across bacteria, and in evolutionarily related mitochondria and chloroplasts. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Export and Localization > RNA Localization RNA Turnover and Surveillance > Regulation of RNA Stability.
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Affiliation(s)
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
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18
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Wang J, Hao F, Song K, Jin W, Fu B, Wei Y, Shi Y, Guo H, Liu W. Identification of a Novel NtLRR-RLK and Biological Pathways That Contribute to Tolerance of TMV in Nicotiana tabacum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:996-1006. [PMID: 32196398 DOI: 10.1094/mpmi-12-19-0343-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Tobacco mosaic virus (TMV) infection can causes serious damage to tobacco crops. To explore the approach of preventing TMV infection of plants, two tobacco cultivars with different resistances to TMV were used to analyze transcription profiling before and after TMV infection. The involvement of biological pathways differed between the tolerant variety (Yuyan8) and the susceptible variety (NC89). In particular, the plant-virus interaction pathway was rapidly activated in Yuyan8, and specific resistance genes were enriched. Liquid chromatography tandem mass spectrometry analysis detected large quantities of antiviral substances in the tolerant Yuyan8. A novel Nicotiana tabacum leucine-rich repeat receptor kinase (NtLRR-RLK) gene was identified as being methylated and this was verified using bisulfite sequencing. Transient expression of TMV-green fluorescent protein in pRNAi-NtLRR-RLK transgenic plants confirmed that NtLRR-RLK was important for susceptibility to TMV. The specific protein interaction map generated from our study revealed that levels of BIP1, E3 ubiquitin ligase, and LRR-RLK were significantly elevated, and all were represented at node positions in the protein interaction map. The same expression tendency of these proteins was also found in pRNAi-NtLRR-RLK transgenic plants at 24 h after TMV inoculation. These data suggested that specific genes in the infection process can activate the immune signal cascade through different resistance genes, and the integration of signal pathways could produce resistance to the virus. These results contribute to the overall understanding of the molecular basis of plant resistance to TMV and in the long term could identify new strategies for prevention and control virus infection.
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Affiliation(s)
- Jing Wang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou, China
| | - Fengsheng Hao
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Kunfeng Song
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Weihuan Jin
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Bo Fu
- College of Tobacco Science, Henan Agricultural University, Zhengzhou, China
| | - Yuanfang Wei
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Yongchun Shi
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Hongxiang Guo
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Weiqun Liu
- College of Tobacco Science, Henan Agricultural University, Zhengzhou, China
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
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19
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Melki I, Frémond ML. Type I Interferonopathies: from a Novel Concept to Targeted Therapeutics. Curr Rheumatol Rep 2020; 22:32. [DOI: 10.1007/s11926-020-00909-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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20
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Eaton A, Hartley T, Kernohan K, Ito Y, Lamont R, Parboosingh J, Barrowman N, Innes AM, Boycott K. When to think outside the autozygome: Best practices for exome sequencing in "consanguineous" families. Clin Genet 2020; 97:835-843. [PMID: 32162313 DOI: 10.1111/cge.13736] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/15/2020] [Accepted: 03/09/2020] [Indexed: 12/14/2022]
Abstract
Exome sequencing (ES) is an effective diagnostic tool with a high yield in consanguineous families. However, how diagnostic yield and mode of inheritance relate to family structure has not been well delineated. We reviewed ES results from families enrolled in the Care4Rare Canada research consortium with various degrees of consanguinity. We contrasted the diagnostic yield in families with parents who are second cousins or closer ("close" consanguinity) vs those more distantly related or from isolated populations ("presumed" consanguinity). We further stratified by number of affected individuals (multiple affected ["multiplex"] vs single affected [simplex]). The overall yield in 116 families was 45.7% (n = 53) with no significant difference between subgroups. Homozygous variants accounted for 100% and 75% of diagnoses in close and presumed consanguineous multiplex families, respectively. In simplex presumed consanguineous families, a striking 46.2% of diagnoses were due to de novo variants, vs only 11.8% in simplex closely consanguineous families (88.2% homozygous). Our data underscores the high yield of ES in consanguineous families and highlights that while a singleton approach may frequently be reasonable and a responsible use of resources, trio sequencing should be strongly considered in simplex families in the absence of confirmed consanguinity given the proportion of de novo variants.
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Affiliation(s)
- Alison Eaton
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Taila Hartley
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Kristin Kernohan
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada.,Newborn Screening Ontario, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Yoko Ito
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Ryan Lamont
- Alberta Children's Hospital Research Institute, Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jillian Parboosingh
- Alberta Children's Hospital Research Institute, Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nick Barrowman
- Clinical Research Unit, Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
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- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - A Micheil Innes
- Alberta Children's Hospital Research Institute, Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kym Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
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21
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Analysis of mitochondrial m1A/G RNA modification reveals links to nuclear genetic variants and associated disease processes. Commun Biol 2020; 3:147. [PMID: 32221480 PMCID: PMC7101319 DOI: 10.1038/s42003-020-0879-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 03/06/2020] [Indexed: 12/13/2022] Open
Abstract
RNA modifications affect the stability and function of RNA species, regulating important downstream processes. Modification levels are often dynamic, varying between tissues and individuals, although it is not always clear what modulates this or what impact it has on biological systems. Here, we quantify variation in m1A/G RNA modification levels at functionally important positions in the human mitochondrial genome across 11,552 samples from 39 tissue/cell types and find that modification levels are associated with mitochondrial transcript processing. We identify links between mitochondrial RNA modification levels and genetic variants in the nuclear genome, including a missense mutation in LONP1, and find that genetic variants within MRPP3 and TRMT61B are associated with RNA modification levels across a large number of tissues. Genetic variants linked to RNA modification levels are associated with multiple disease/disease-related phenotypes, including blood pressure, breast cancer and psoriasis, suggesting a role for mitochondrial RNA modification in complex disease. Ali et al. analyze publicly available RNA-seq data from different tissues to quantify variation in m1A/G methylation levels in mitochondrial RNAs. They show a link between mitochondrial m1A/G modification levels and nuclear genetic variants, many of which are associated with disease.
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22
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Lee JS, Yoo T, Lee M, Lee Y, Jeon E, Kim SY, Lim BC, Kim KJ, Choi M, Chae JH. Genetic heterogeneity in Leigh syndrome: Highlighting treatable and novel genetic causes. Clin Genet 2020; 97:586-594. [PMID: 32020600 DOI: 10.1111/cge.13713] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/14/2020] [Accepted: 01/30/2020] [Indexed: 01/02/2023]
Abstract
Leigh syndrome (LS), the most common childhood mitochondrial disorder, has characteristic clinical and neuroradiologic features. Mutations in more than 75 genes have been identified in both the mitochondrial and nuclear genome, implicating a high degree of genetic heterogeneity in LS. To profile these genetic signatures and understand the pathophysiology of LS, we recruited 64 patients from 62 families who were clinically diagnosed with LS at Seoul National University Children's Hospital. Mitochondrial genetic analysis followed by whole-exome sequencing was performed on 61 patients. Pathogenic variants in mitochondrial DNA were identified in 18 families and nuclear DNA mutations in 22. The following 17 genes analyzed in 40 families were found to have genetic complexity: MTATP6, MTND1, MTND3, MTND5, MTND6, MTTK, NDUFS1, NDUFV1, NDUFAF6, SURF1, SLC19A3, ECHS1, PNPT1, IARS2, NARS2, VPS13D, and NAXE. Two treatable cases had biotin-thiamine responsive basal ganglia disease, and another three were identified as having defects in the newly recognized genes (VPS13D or NAXE). Variants in the nuclear genes that encoded mitochondrial aminoacyl tRNA synthetases were present in 27.3% of cases. Our findings expand the genetic and clinical spectrum of LS, showing genetic heterogeneity and highlighting treatable cases and those with novel genetic causes.
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Affiliation(s)
- Jin Sook Lee
- Department of Pediatrics, Department of Genome Medicine and Science, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea
| | - Taekyeong Yoo
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Moses Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Youngha Lee
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Eunyoung Jeon
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Soo Yeon Kim
- Department of Pediatrics, Pediatric Clinical Neuroscience Center, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Byung Chan Lim
- Department of Pediatrics, Pediatric Clinical Neuroscience Center, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Ki Joong Kim
- Department of Pediatrics, Pediatric Clinical Neuroscience Center, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Murim Choi
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Jong-Hee Chae
- Department of Pediatrics, Pediatric Clinical Neuroscience Center, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea.,Rare Disease Center, Seoul National University Hospital, Seoul, Koreal
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23
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Cheng Y, Liu P, Zheng Q, Gao G, Yuan J, Wang P, Huang J, Xie L, Lu X, Tong T, Chen J, Lu Z, Guan J, Wang G. Mitochondrial Trafficking and Processing of Telomerase RNA TERC. Cell Rep 2019; 24:2589-2595. [PMID: 30184494 DOI: 10.1016/j.celrep.2018.08.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/17/2018] [Accepted: 07/31/2018] [Indexed: 01/18/2023] Open
Abstract
Mitochondrial dysfunctions play major roles in many diseases. However, how mitochondrial stresses are relayed to downstream responses remains unclear. Here we show that the RNA component of mammalian telomerase TERC is imported into mitochondria, processed to a shorter form TERC-53, and then exported back to the cytosol. We found that the import is regulated by PNPASE, and the processing is controlled by mitochondrion-localized RNASET2. Cytosolic TERC-53 levels respond to changes in mitochondrial functions but have no direct effect on these functions. These findings uncover a mitochondrial RNA trafficking pathway and provide a potential mechanism for mitochondria to relay their functional states to other cellular compartments.
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Affiliation(s)
- Ying Cheng
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Peipei Liu
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qian Zheng
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ge Gao
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiapei Yuan
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Pengfeng Wang
- Peking University Research Center on Aging, Beijing 100191, China
| | - Jinliang Huang
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Leiming Xie
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xinping Lu
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Tanjun Tong
- Peking University Research Center on Aging, Beijing 100191, China; Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China
| | - Jun Chen
- Peking University Research Center on Aging, Beijing 100191, China; Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China
| | - Zhi Lu
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jisong Guan
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Geng Wang
- MOE Key Laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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24
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Rius R, Van Bergen NJ, Compton AG, Riley LG, Kava MP, Balasubramaniam S, Amor DJ, Fanjul-Fernandez M, Cowley MJ, Fahey MC, Koenig MK, Enns GM, Sadedin S, Wilson MJ, Tan TY, Thorburn DR, Christodoulou J. Clinical Spectrum and Functional Consequences Associated with Bi-Allelic Pathogenic PNPT1 Variants. J Clin Med 2019; 8:jcm8112020. [PMID: 31752325 PMCID: PMC6912252 DOI: 10.3390/jcm8112020] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 02/01/2023] Open
Abstract
PNPT1 (PNPase—polynucleotide phosphorylase) is involved in multiple RNA processing functions in the mitochondria. Bi-allelic pathogenic PNPT1 variants cause heterogeneous clinical phenotypes affecting multiple organs without any established genotype–phenotype correlations. Defects in PNPase can cause variable combined respiratory chain complex defects. Recently, it has been suggested that PNPase can lead to activation of an innate immune response. To better understand the clinical and molecular spectrum of patients with bi-allelic PNPT1 variants, we captured detailed clinical and molecular phenotypes of all 17 patients reported in the literature, plus seven new patients, including a 78-year-old male with the longest reported survival. A functional follow-up of genomic sequencing by cDNA studies confirmed a splicing defect in a novel, apparently synonymous, variant. Patient fibroblasts showed an accumulation of mitochondrial unprocessed PNPT1 transcripts, while blood showed an increased interferon response. Our findings suggest that functional analyses of the RNA processing function of PNPase are more sensitive than testing downstream defects in oxidative phosphorylation (OXPHPOS) enzyme activities. This research extends our knowledge of the clinical and functional consequences of bi-allelic pathogenic PNPT1 variants that may guide management and further efforts into understanding the pathophysiological mechanisms for therapeutic development.
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Affiliation(s)
- Rocio Rius
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Nicole J. Van Bergen
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Alison G. Compton
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Lisa G. Riley
- Kids Research, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
- Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW 2050, Australia
| | - Maina P. Kava
- Department of Neurology, Perth Children’s Hospital, Perth, WA 6009, Australia
- Department of Metabolic Medicine and Rheumatology, Perth Children’s Hospital, Perth, WA 6009, Australia
| | - Shanti Balasubramaniam
- Department of Metabolic Medicine and Rheumatology, Perth Children’s Hospital, Perth, WA 6009, Australia
- Genetic Metabolic Disorders Service, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
- Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, NSW 2145, Australia
| | - David J. Amor
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
| | - Miriam Fanjul-Fernandez
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
| | - Mark J. Cowley
- Precision Medicine Theme, Children’s Cancer Institute, Kensington, NSW 2750, Australia
- Kinghorn Centre for Clinical Genomics, Garvan Institute, University of New South Wales, Randwick, NSW 2010, Australia
- School of Women’s and Children’s Health, University of New South Wales, Randwick, NSW 2031, Australia
| | - Michael C. Fahey
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
| | - Mary K. Koenig
- The University of Texas McGovern Medical School, Houston, TX 77030, USA
| | - Gregory M. Enns
- Department of Pediatrics, Division of Medical Genetics, Stanford University, Stanford, CA 94305, USA
| | - Simon Sadedin
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
| | - Meredith J. Wilson
- Department of Clinical Genetics, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
- Discipline of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Tiong Y. Tan
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
| | - David R. Thorburn
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
| | - John Christodoulou
- Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
- Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW 2050, Australia
- Victorian Clinical Genetic Services, Melbourne, VIC 3052, Australia
- Correspondence: ; Tel.: +613-9936-6353
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25
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Pajak A, Laine I, Clemente P, El-Fissi N, Schober FA, Maffezzini C, Calvo-Garrido J, Wibom R, Filograna R, Dhir A, Wedell A, Freyer C, Wredenberg A. Defects of mitochondrial RNA turnover lead to the accumulation of double-stranded RNA in vivo. PLoS Genet 2019; 15:e1008240. [PMID: 31365523 PMCID: PMC6668790 DOI: 10.1371/journal.pgen.1008240] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 06/11/2019] [Indexed: 12/02/2022] Open
Abstract
The RNA helicase SUV3 and the polynucleotide phosphorylase PNPase are involved in the degradation of mitochondrial mRNAs but their roles in vivo are not fully understood. Additionally, upstream processes, such as transcript maturation, have been linked to some of these factors, suggesting either dual roles or tightly interconnected mechanisms of mitochondrial RNA metabolism. To get a better understanding of the turn-over of mitochondrial RNAs in vivo, we manipulated the mitochondrial mRNA degrading complex in Drosophila melanogaster models and studied the molecular consequences. Additionally, we investigated if and how these factors interact with the mitochondrial poly(A) polymerase, MTPAP, as well as with the mitochondrial mRNA stabilising factor, LRPPRC. Our results demonstrate a tight interdependency of mitochondrial mRNA stability, polyadenylation and the removal of antisense RNA. Furthermore, disruption of degradation, as well as polyadenylation, leads to the accumulation of double-stranded RNAs, and their escape out into the cytoplasm is associated with an altered immune-response in flies. Together our results suggest a highly organised and inter-dependable regulation of mitochondrial RNA metabolism with far reaching consequences on cellular physiology. Although a number of factors have been implemented in the turnover of mitochondrial (mt) DNA-derived transcripts, their exact functions and interplay with one another is not entirely clear. Several of these factors have been proposed to co-ordinately regulate both transcript maturation, as well as degradation, but the order of events during mitochondrial RNA turnover is less well understood. Using a range of different genetically modified Drosophila melanogaster models, we studied the involvement of the RNA helicase SUV3, the polynucleotide phosphorylase PNPase, the leucine-rich pentatricopeptide repeat motif-containing protein LRPPRC, and the mitochondrial RNA poly(A) polymerase MTPAP, in stabilisation, polyadenylation, and degradation of mitochondrial transcripts. Our results show a tight collaborative activity of these factors in vivo and reveal a clear hierarchical order of events leading to mitochondrial mRNA maturation. Furthermore, we demonstrate that the loss of SUV3, PNPase, or MTPAP leads to the accumulation of mitochondrial-derived antisense RNA in the cytoplasm of cells, which is associated with an altered immune-response in flies.
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Affiliation(s)
- Aleksandra Pajak
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Isabelle Laine
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Paula Clemente
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Najla El-Fissi
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Florian A. Schober
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Camilla Maffezzini
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Javier Calvo-Garrido
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Rolf Wibom
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Roberta Filograna
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Ashish Dhir
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Anna Wedell
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Christoph Freyer
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
- * E-mail: (CF); (AW)
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
- * E-mail: (CF); (AW)
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26
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Transcription, Processing, and Decay of Mitochondrial RNA in Health and Disease. Int J Mol Sci 2019; 20:ijms20092221. [PMID: 31064115 PMCID: PMC6540609 DOI: 10.3390/ijms20092221] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/01/2019] [Accepted: 05/03/2019] [Indexed: 12/16/2022] Open
Abstract
Although the large majority of mitochondrial proteins are nuclear encoded, for their correct functioning mitochondria require the expression of 13 proteins, two rRNA, and 22 tRNA codified by mitochondrial DNA (mtDNA). Once transcribed, mitochondrial RNA (mtRNA) is processed, mito-ribosomes are assembled, and mtDNA-encoded proteins belonging to the respiratory chain are synthesized. These processes require the coordinated spatio-temporal action of several enzymes, and many different factors are involved in the regulation and control of protein synthesis and in the stability and turnover of mitochondrial RNA. In this review, we describe the essential steps of mitochondrial RNA synthesis, maturation, and degradation, the factors controlling these processes, and how the alteration of these processes is associated with human pathologies.
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27
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Wen X, Zhang X, Hu Y, Xu J, Wang T, Yin S. iTRAQ-based quantitative proteomic analysis of Takifugu fasciatus liver in response to low-temperature stress. J Proteomics 2019; 201:27-36. [PMID: 30954612 DOI: 10.1016/j.jprot.2019.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/25/2019] [Accepted: 04/03/2019] [Indexed: 10/27/2022]
Abstract
Low temperatures profoundly influence the physiological and behavioural processes of ectotherms, especially teleosts, which have made them the subjects of strong interest over time. However, the characteristics of fish cold-tolerance at the protein level remain unclear. Therefore, to shed further light on the molecular mechanisms of low temperature adaptation in fish, we conducted quantitative proteomics on the T. fasciatus liver using iTRAQ. Comparing the proteomic profiles of the T. fasciatus liver at 12 °C and 26 °C, a total of 3741 proteins were identified, and 160 were differentially abundant proteins (DAPs). Among the DAPs, the most significant changes were noted in proteins involved in oxidative stress (nine proteins), mitochondrial enzymes (eleven proteins) and signal transduction (thirteen proteins). The KEGG enrichment analysis indicated significant enhancement of D-arginine and D-ornithine metabolism, MAPK signalling, Wnt signalling and Gap junction pathway. Subsequently, three significantly up-regulated proteins (CIRB, HSP90 and GST) and two significantly down-regulated proteins (FLNB and A2ML1) were validated with parallel reaction monitoring (PRM) assays. Furthermore, the changes in abundance of proteins that are involved in oxidative stress, mitochondrial enzymes and signal transduction were validated at the transcriptional level with qPCR. These verification results show that the experimental data of iTRAQ are reliable. Our results not only deepen the understanding of the mechanisms underlying low-temperature tolerance in fish, but they also may contribute to the enhancement of cold tolerance during its breeding process. SIGNIFICANCE OF THE STUDY: The study focused on a comparative quantitative proteomics analysis of the T. fasciatus liver in response to low temperatures using iTRAQ, which has not yet been reported in the literatures. The results showed that the effect of low temperature on T. fasciatus is significant, including a detoxification of metabolic by-products and oxidative stress, an activation of the mitochondrial enzyme to strengthen energy metabolism, and a negative effect on signal transduction, which result in dysfunction or suboptimal performance. These low-temperature-related changes in the liver proteome of T. fasciatus can facilitate the understanding of the low temperature-related response that takes place in similar conditions in the liver and may contribute to the breeding of cold-resistant strains.
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Affiliation(s)
- Xin Wen
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Xinyu Zhang
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Yadong Hu
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Jiejie Xu
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Tao Wang
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China.
| | - Shaowu Yin
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China.
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28
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Jeandard D, Smirnova A, Tarassov I, Barrey E, Smirnov A, Entelis N. Import of Non-Coding RNAs into Human Mitochondria: A Critical Review and Emerging Approaches. Cells 2019; 8:E286. [PMID: 30917553 PMCID: PMC6468882 DOI: 10.3390/cells8030286] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 03/19/2019] [Accepted: 03/23/2019] [Indexed: 01/26/2023] Open
Abstract
Mitochondria harbor their own genetic system, yet critically depend on the import of a number of nuclear-encoded macromolecules to ensure their expression. In all eukaryotes, selected non-coding RNAs produced from the nuclear genome are partially redirected into the mitochondria, where they participate in gene expression. Therefore, the mitochondrial RNome represents an intricate mixture of the intrinsic transcriptome and the extrinsic RNA importome. In this review, we summarize and critically analyze data on the nuclear-encoded transcripts detected in human mitochondria and outline the proposed molecular mechanisms of their mitochondrial import. Special attention is given to the various experimental approaches used to study the mitochondrial RNome, including some recently developed genome-wide and in situ techniques.
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Affiliation(s)
- Damien Jeandard
- UMR 7156 GMGM Strasbourg University/CNRS, 67000 Strasbourg, France.
| | - Anna Smirnova
- UMR 7156 GMGM Strasbourg University/CNRS, 67000 Strasbourg, France.
| | - Ivan Tarassov
- UMR 7156 GMGM Strasbourg University/CNRS, 67000 Strasbourg, France.
| | - Eric Barrey
- GABI-UMR1313, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France.
| | | | - Nina Entelis
- UMR 7156 GMGM Strasbourg University/CNRS, 67000 Strasbourg, France.
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29
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Zheng Q, Liu P, Gao G, Yuan J, Wang P, Huang J, Xie L, Lu X, Di F, Tong T, Chen J, Lu Z, Guan J, Wang G. Mitochondrion-processed TERC regulates senescence without affecting telomerase activities. Protein Cell 2019; 10:631-648. [PMID: 30788732 PMCID: PMC6711880 DOI: 10.1007/s13238-019-0612-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 01/15/2019] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial dysfunctions play major roles in ageing. How mitochondrial stresses invoke downstream responses and how specificity of the signaling is achieved, however, remains unclear. We have previously discovered that the RNA component of Telomerase TERC is imported into mitochondria, processed to a shorter form TERC-53, and then exported back to the cytosol. Cytosolic TERC-53 levels respond to mitochondrial functions, but have no direct effect on these functions, suggesting that cytosolic TERC-53 functions downstream of mitochondria as a signal of mitochondrial functions. Here, we show that cytosolic TERC-53 plays a regulatory role on cellular senescence and is involved in cognition decline in 10 months old mice, independent of its telomerase function. Manipulation of cytosolic TERC-53 levels affects cellular senescence and cognition decline in 10 months old mouse hippocampi without affecting telomerase activity, and most importantly, affects cellular senescence in terc−/− cells. These findings uncover a senescence-related regulatory pathway with a non-coding RNA as the signal in mammals.
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Affiliation(s)
- Qian Zheng
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Peipei Liu
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Ge Gao
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jiapei Yuan
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Pengfeng Wang
- Peking University Research Center on Aging, Beijing, 100191, China
| | - Jinliang Huang
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Leiming Xie
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xinping Lu
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Fan Di
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Tanjun Tong
- Peking University Research Center on Aging, Beijing, 100191, China.,Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, 100191, China
| | - Jun Chen
- Peking University Research Center on Aging, Beijing, 100191, China.,Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, 100191, China
| | - Zhi Lu
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jisong Guan
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Geng Wang
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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30
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Zhou Z, Austin GL, Young LEA, Johnson LA, Sun R. Mitochondrial Metabolism in Major Neurological Diseases. Cells 2018; 7:E229. [PMID: 30477120 PMCID: PMC6316877 DOI: 10.3390/cells7120229] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 01/18/2023] Open
Abstract
Mitochondria are bilayer sub-cellular organelles that are an integral part of normal cellular physiology. They are responsible for producing the majority of a cell's ATP, thus supplying energy for a variety of key cellular processes, especially in the brain. Although energy production is a key aspect of mitochondrial metabolism, its role extends far beyond energy production to cell signaling and epigenetic regulation⁻functions that contribute to cellular proliferation, differentiation, apoptosis, migration, and autophagy. Recent research on neurological disorders suggest a major metabolic component in disease pathophysiology, and mitochondria have been shown to be in the center of metabolic dysregulation and possibly disease manifestation. This review will discuss the basic functions of mitochondria and how alterations in mitochondrial activity lead to neurological disease progression.
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Affiliation(s)
- Zhengqiu Zhou
- Molecular & Cellular Biochemistry Department, University of Kentucky, Lexington, KY 40536, USA.
| | - Grant L Austin
- Molecular & Cellular Biochemistry Department, University of Kentucky, Lexington, KY 40536, USA.
| | - Lyndsay E A Young
- Molecular & Cellular Biochemistry Department, University of Kentucky, Lexington, KY 40536, USA.
| | - Lance A Johnson
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA.
| | - Ramon Sun
- Molecular & Cellular Biochemistry Department, University of Kentucky, Lexington, KY 40536, USA.
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31
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Cameron TA, Matz LM, De Lay NR. Polynucleotide phosphorylase: Not merely an RNase but a pivotal post-transcriptional regulator. PLoS Genet 2018; 14:e1007654. [PMID: 30307990 PMCID: PMC6181284 DOI: 10.1371/journal.pgen.1007654] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Almost 60 years ago, Severo Ochoa was awarded the Nobel Prize in Physiology or Medicine for his discovery of the enzymatic synthesis of RNA by polynucleotide phosphorylase (PNPase). Although this discovery provided an important tool for deciphering the genetic code, subsequent work revealed that the predominant function of PNPase in bacteria and eukaryotes is catalyzing the reverse reaction, i.e., the release of ribonucleotides from RNA. PNPase has a crucial role in RNA metabolism in bacteria and eukaryotes mainly through its roles in processing and degrading RNAs, but additional functions in RNA metabolism have recently been reported for this enzyme. Here, we discuss these established and noncanonical functions for PNPase and the possibility that the major impact of PNPase on cell physiology is through its unorthodox roles.
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Affiliation(s)
- Todd A. Cameron
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Lisa M. Matz
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, United States of America
| | - Nicholas R. De Lay
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, United States of America
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, Texas, United States of America
- * E-mail:
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32
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Is PNPT1
-related hearing loss ever non-syndromic? Whole exome sequencing of adult siblings expands the natural history of PNPT1
-related disorders. Am J Med Genet A 2018; 176:2487-2493. [DOI: 10.1002/ajmg.a.40516] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/27/2018] [Accepted: 07/27/2018] [Indexed: 11/07/2022]
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33
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Golzarroshan B, Lin CL, Li CL, Yang WZ, Chu LY, Agrawal S, Yuan HS. Crystal structure of dimeric human PNPase reveals why disease-linked mutants suffer from low RNA import and degradation activities. Nucleic Acids Res 2018; 46:8630-8640. [PMID: 30020492 PMCID: PMC6144817 DOI: 10.1093/nar/gky642] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/13/2018] [Accepted: 07/16/2018] [Indexed: 11/13/2022] Open
Abstract
Human polynucleotide phosphorylase (PNPase) is an evolutionarily conserved 3'-to-5' exoribonuclease principally located in mitochondria where it is responsible for RNA turnover and import. Mutations in PNPase impair structured RNA transport into mitochondria, resulting in mitochondrial dysfunction and disease. PNPase is a trimeric protein with a doughnut-shaped structure hosting a central channel for single-stranded RNA binding and degradation. Here, we show that the disease-linked human PNPase mutants, Q387R and E475G, form dimers, not trimers, and have significantly lower RNA binding and degradation activities compared to wild-type trimeric PNPase. Moreover, S1 domain-truncated PNPase binds single-stranded RNA but not the stem-loop signature motif of imported structured RNA, suggesting that the S1 domain is responsible for binding structured RNAs. We further determined the crystal structure of dimeric PNPase at a resolution of 2.8 Å and, combined with small-angle X-ray scattering, show that the RNA-binding K homology and S1 domains are relatively inaccessible in the dimeric assembly. Taken together, these results show that mutations at the interface of the trimeric PNPase tend to produce a dimeric protein with destructive RNA-binding surfaces, thus impairing both of its RNA import and degradation activities and leading to mitochondria disorders.
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Affiliation(s)
- Bagher Golzarroshan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic of China
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, Republic of China
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China
| | - Chia-Liang Lin
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic of China
| | - Chia-Lung Li
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic of China
| | - Wei-Zen Yang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic of China
| | - Lee-Ya Chu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic of China
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, Republic of China
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China
| | - Sashank Agrawal
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic of China
- Molecular and Cell Biology Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, Republic of China
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan 11490, Republic of China
| | - Hanna S Yuan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, Republic of China
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, Republic of China
- Molecular and Cell Biology Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, Republic of China
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34
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Loutre R, Heckel AM, Smirnova A, Entelis N, Tarassov I. Can Mitochondrial DNA be CRISPRized: Pro and Contra. IUBMB Life 2018; 70:1233-1239. [PMID: 30184317 DOI: 10.1002/iub.1919] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/03/2018] [Accepted: 07/05/2018] [Indexed: 01/08/2023]
Abstract
Mitochondria represent a chimera of macromolecules encoded either in the organellar genome, mtDNA, or in the nuclear one. If the pathway of protein targeting to different sub-compartments of mitochondria was relatively well studied, import of small noncoding RNAs into mammalian mitochondria still awaits mechanistic explanations and its functional issues are often not understood thus raising polemics. At the same time, RNA mitochondrial import pathway has an obvious attractiveness as it appears as a unique natural mechanism permitting to address nucleic acids into the organelles. Deciphering the function(s) of imported RNAs inside the mitochondria is extremely complicated due to their relatively low abundance, which suggests their regulatory role. We previously demonstrated that mitochondrial targeting of small noncoding RNAs able to specifically anneal with the mutant mitochondrial DNA led to a decrease of the mtDNA heteroplasmy level by inhibiting mutant mtDNA replication. We then demonstrated that increasing level of expression of such antireplicative recombinant RNAs increases significantly the antireplicative effect. In this report, we present a new data investigating the possibility to establish a CRISPR-Cas9 system targeting mtDNA exploiting of the pathway of RNA import into mitochondria. Mitochondrially addressed Cas9 versions and a set of mitochondrially targeted guide RNAs were tested in vitro and in vivo and their effect on mtDNA copy number was demonstrated. So far, the system appeared as more complicated for use than previously found for nuclear DNA, because only application of a pair of guide RNAs produced the effect of mtDNA depletion. We discuss, in a critical way, these results and put them in a broader context of polemics concerning the possibilities of manipulation of mtDNA in mammalians. The findings described here prove the potential of the RNA import pathway as a tool for studying mtDNA and for future therapy of mitochondrial disorders. © The Authors. IUBMB Life published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 70(12):1233-1239, 2018.
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Affiliation(s)
- Romuald Loutre
- UMR 7156 GMGM (Molecular Genetics, Genomics, Microbiology), University of Strasbourg - CNRS, Strasbourg, France
| | - Anne-Marie Heckel
- UMR 7156 GMGM (Molecular Genetics, Genomics, Microbiology), University of Strasbourg - CNRS, Strasbourg, France
| | - Anna Smirnova
- UMR 7156 GMGM (Molecular Genetics, Genomics, Microbiology), University of Strasbourg - CNRS, Strasbourg, France
| | - Nina Entelis
- UMR 7156 GMGM (Molecular Genetics, Genomics, Microbiology), University of Strasbourg - CNRS, Strasbourg, France
| | - Ivan Tarassov
- UMR 7156 GMGM (Molecular Genetics, Genomics, Microbiology), University of Strasbourg - CNRS, Strasbourg, France
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35
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Dhir A, Dhir S, Borowski LS, Jimenez L, Teitell M, Rötig A, Crow YJ, Rice GI, Duffy D, Tamby C, Nojima T, Munnich A, Schiff M, de Almeida CR, Rehwinkel J, Dziembowski A, Szczesny RJ, Proudfoot NJ. Mitochondrial double-stranded RNA triggers antiviral signalling in humans. Nature 2018; 560:238-242. [PMID: 30046113 DOI: 10.1038/s41586-018-0363-0] [Citation(s) in RCA: 380] [Impact Index Per Article: 63.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/06/2018] [Indexed: 11/09/2022]
Abstract
Mitochondria are descendants of endosymbiotic bacteria and retain essential prokaryotic features such as a compact circular genome. Consequently, in mammals, mitochondrial DNA is subjected to bidirectional transcription that generates overlapping transcripts, which are capable of forming long double-stranded RNA structures1,2. However, to our knowledge, mitochondrial double-stranded RNA has not been previously characterized in vivo. Here we describe the presence of a highly unstable native mitochondrial double-stranded RNA species at single-cell level and identify key roles for the degradosome components mitochondrial RNA helicase SUV3 and polynucleotide phosphorylase PNPase in restricting the levels of mitochondrial double-stranded RNA. Loss of either enzyme results in massive accumulation of mitochondrial double-stranded RNA that escapes into the cytoplasm in a PNPase-dependent manner. This process engages an MDA5-driven antiviral signalling pathway that triggers a type I interferon response. Consistent with these data, patients carrying hypomorphic mutations in the gene PNPT1, which encodes PNPase, display mitochondrial double-stranded RNA accumulation coupled with upregulation of interferon-stimulated genes and other markers of immune activation. The localization of PNPase to the mitochondrial inter-membrane space and matrix suggests that it has a dual role in preventing the formation and release of mitochondrial double-stranded RNA into the cytoplasm. This in turn prevents the activation of potent innate immune defence mechanisms that have evolved to protect vertebrates against microbial and viral attack.
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Affiliation(s)
- Ashish Dhir
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
| | - Somdutta Dhir
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Lukasz S Borowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Laura Jimenez
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Michael Teitell
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Agnès Rötig
- INSERM UMR1163, Institut Imagine, Paris, France
| | - Yanick J Crow
- INSERM UMR1163, Institut Imagine, Paris, France.,Paris Descartes University, Sorbonne-Paris-Cité, Institut Imagine, Paris, France.,Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Gillian I Rice
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Darragh Duffy
- Immunobiology of Dendritic Cells, Institut Pasteur, Paris, France.,INSERM U1223, Paris, France
| | | | - Takayuki Nojima
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | | | | | - Jan Rehwinkel
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Andrzej Dziembowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Roman J Szczesny
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland. .,Faculty of Biology, University of Warsaw, Warsaw, Poland.
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36
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Mitochondrial DNA transcription and translation: clinical syndromes. Essays Biochem 2018; 62:321-340. [PMID: 29980628 PMCID: PMC6056718 DOI: 10.1042/ebc20170103] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/17/2018] [Accepted: 05/21/2018] [Indexed: 01/15/2023]
Abstract
Diagnosing primary mitochondrial diseases is challenging in clinical practice. Although, defective oxidative phosphorylation (OXPHOS) is the common final pathway, it is unknown why different mtDNA or nuclear mutations result in largely heterogeneous and often tissue -specific clinical presentations. Mitochondrial tRNA (mt-tRNA) mutations are frequent causes of mitochondrial diseases both in children and adults. However numerous nuclear mutations involved in mitochondrial protein synthesis affecting ubiquitously expressed genes have been reported in association with very tissue specific clinical manifestations suggesting that there are so far unknown factors determining the tissue specificity in mitochondrial translation. Most of these gene defects result in histological abnormalities and multiple respiratory chain defects in the affected organs. The clinical phenotypes are usually early-onset, severe, and often fatal, implying the importance of mitochondrial translation from birth. However, some rare, reversible infantile mitochondrial diseases are caused by very specific defects of mitochondrial translation. An unbiased genetic approach (whole exome sequencing, RNA sequencing) combined with proteomics and functional studies revealed novel factors involved in mitochondrial translation which contribute to the clinical manifestation and recovery in these rare reversible mitochondrial conditions.
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37
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Shimada E, Ahsan FM, Nili M, Huang D, Atamdede S, TeSlaa T, Case D, Yu X, Gregory BD, Perrin BJ, Koehler CM, Teitell MA. PNPase knockout results in mtDNA loss and an altered metabolic gene expression program. PLoS One 2018; 13:e0200925. [PMID: 30024931 PMCID: PMC6053217 DOI: 10.1371/journal.pone.0200925] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 07/05/2018] [Indexed: 01/10/2023] Open
Abstract
Polynucleotide phosphorylase (PNPase) is an essential mitochondria-localized exoribonuclease implicated in multiple biological processes and human disorders. To reveal role(s) for PNPase in mitochondria, we established PNPase knockout (PKO) systems by first shifting culture conditions to enable cell growth with defective respiration. Interestingly, PKO established in mouse embryonic fibroblasts (MEFs) resulted in the loss of mitochondrial DNA (mtDNA). The transcriptional profile of PKO cells was similar to rho0 mtDNA deleted cells, with perturbations in cholesterol (FDR = 6.35 x 10-13), lipid (FDR = 3.21 x 10-11), and secondary alcohol (FDR = 1.04x10-12) metabolic pathway gene expression compared to wild type parental (TM6) MEFs. Transcriptome analysis indicates processes related to axonogenesis (FDR = 4.49 x 10-3), axon development (FDR = 4.74 x 10-3), and axonal guidance (FDR = 4.74 x 10-3) were overrepresented in PKO cells, consistent with previous studies detailing causative PNPase mutations in delayed myelination, hearing loss, encephalomyopathy, and chorioretinal defects in humans. Overrepresentation analysis revealed alterations in metabolic pathways in both PKO and rho0 cells. Therefore, we assessed the correlation of genes implicated in cell cycle progression and total metabolism and observed a strong positive correlation between PKO cells and rho0 MEFs compared to TM6 MEFs. We quantified the normalized biomass accumulation rate of PKO clones at 1.7% (SD ± 2.0%) and 2.4% (SD ± 1.6%) per hour, which was lower than TM6 cells at 3.3% (SD ± 3.5%) per hour. Furthermore, PKO in mouse inner ear hair cells caused progressive hearing loss that parallels human familial hearing loss previously linked to mutations in PNPase. Combined, our study reports that knockout of a mitochondrial nuclease results in mtDNA loss and suggests that mtDNA maintenance could provide a unifying connection for the large number of biological activities reported for PNPase.
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Affiliation(s)
- Eriko Shimada
- Molecular Biology Institute Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
| | - Fasih M. Ahsan
- Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Mahta Nili
- Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Dian Huang
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Sean Atamdede
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, United States of America
| | - Tara TeSlaa
- Molecular Biology Institute Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
| | - Dana Case
- Molecular Biology Institute Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
| | - Xiang Yu
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Brian D. Gregory
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Benjamin J. Perrin
- Department of Biology, Indiana University–Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Carla M. Koehler
- Molecular Biology Institute Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, United States of America
- Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, California, United States of America
| | - Michael A. Teitell
- Molecular Biology Institute Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
- Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, California, United States of America
- Broad Center for Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Pediatrics, University of California Los Angeles, Los Angeles, California, United States of America
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, United States of America
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38
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Sato R, Arai-Ichinoi N, Kikuchi A, Matsuhashi T, Numata-Uematsu Y, Uematsu M, Fujii Y, Murayama K, Ohtake A, Abe T, Kure S. Novel biallelic mutations in the PNPT1
gene encoding a mitochondrial-RNA-import protein PNPase cause delayed myelination. Clin Genet 2017; 93:242-247. [DOI: 10.1111/cge.13068] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/19/2017] [Accepted: 06/05/2017] [Indexed: 12/22/2022]
Affiliation(s)
- R. Sato
- Department of Pediatrics; Tohoku University School of Medicine; Miyagi Japan
| | - N. Arai-Ichinoi
- Department of Pediatrics; Tohoku University School of Medicine; Miyagi Japan
| | - A. Kikuchi
- Department of Pediatrics; Tohoku University School of Medicine; Miyagi Japan
| | - T. Matsuhashi
- Department of Pediatrics; Tohoku University School of Medicine; Miyagi Japan
| | - Y. Numata-Uematsu
- Department of Pediatrics; Tohoku University School of Medicine; Miyagi Japan
| | - M. Uematsu
- Department of Pediatrics; Tohoku University School of Medicine; Miyagi Japan
| | - Y. Fujii
- Department of Pediatrics; Hiroshima University Hospital; Hiroshima Japan
| | - K. Murayama
- Department of Metabolism; Chiba Children's Hospital; Chiba Japan
| | - A. Ohtake
- Department of Pediatrics; Saitama Medical University; Saitama Japan
| | - T. Abe
- Department of Nephrology, Endocrinology, and Vascular Medicine; Tohoku University School of Medicine; Miyagi Japan
| | - S. Kure
- Department of Pediatrics; Tohoku University School of Medicine; Miyagi Japan
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39
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Lake NJ, Webb BD, Stroud DA, Richman TR, Ruzzenente B, Compton AG, Mountford HS, Pulman J, Zangarelli C, Rio M, Boddaert N, Assouline Z, Sherpa MD, Schadt EE, Houten SM, Byrnes J, McCormick EM, Zolkipli-Cunningham Z, Haude K, Zhang Z, Retterer K, Bai R, Calvo SE, Mootha VK, Christodoulou J, Rötig A, Filipovska A, Cristian I, Falk MJ, Metodiev MD, Thorburn DR. Biallelic Mutations in MRPS34 Lead to Instability of the Small Mitoribosomal Subunit and Leigh Syndrome. Am J Hum Genet 2017; 101:239-254. [PMID: 28777931 DOI: 10.1016/j.ajhg.2017.07.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/09/2017] [Indexed: 12/30/2022] Open
Abstract
The synthesis of all 13 mitochondrial DNA (mtDNA)-encoded protein subunits of the human oxidative phosphorylation (OXPHOS) system is carried out by mitochondrial ribosomes (mitoribosomes). Defects in the stability of mitoribosomal proteins or mitoribosome assembly impair mitochondrial protein translation, causing combined OXPHOS enzyme deficiency and clinical disease. Here we report four autosomal-recessive pathogenic mutations in the gene encoding the small mitoribosomal subunit protein, MRPS34, in six subjects from four unrelated families with Leigh syndrome and combined OXPHOS defects. Whole-exome sequencing was used to independently identify all variants. Two splice-site mutations were identified, including homozygous c.321+1G>T in a subject of Italian ancestry and homozygous c.322-10G>A in affected sibling pairs from two unrelated families of Puerto Rican descent. In addition, compound heterozygous MRPS34 mutations were identified in a proband of French ancestry; a missense (c.37G>A [p.Glu13Lys]) and a nonsense (c.94C>T [p.Gln32∗]) variant. We demonstrated that these mutations reduce MRPS34 protein levels and the synthesis of OXPHOS subunits encoded by mtDNA. Examination of the mitoribosome profile and quantitative proteomics showed that the mitochondrial translation defect was caused by destabilization of the small mitoribosomal subunit and impaired monosome assembly. Lentiviral-mediated expression of wild-type MRPS34 rescued the defect in mitochondrial translation observed in skin fibroblasts from affected subjects, confirming the pathogenicity of MRPS34 mutations. Our data establish that MRPS34 is required for normal function of the mitoribosome in humans and furthermore demonstrate the power of quantitative proteomic analysis to identify signatures of defects in specific cellular pathways in fibroblasts from subjects with inherited disease.
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40
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Liu P, Huang J, Zheng Q, Xie L, Lu X, Jin J, Wang G. Mammalian mitochondrial RNAs are degraded in the mitochondrial intermembrane space by RNASET2. Protein Cell 2017; 8:735-749. [PMID: 28730546 PMCID: PMC5636749 DOI: 10.1007/s13238-017-0448-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/06/2017] [Indexed: 10/28/2022] Open
Abstract
Mammalian mitochondrial genome encodes a small set of tRNAs, rRNAs, and mRNAs. The RNA synthesis process has been well characterized. How the RNAs are degraded, however, is poorly understood. It was long assumed that the degradation happens in the matrix where transcription and translation machineries reside. Here we show that contrary to the assumption, mammalian mitochondrial RNA degradation occurs in the mitochondrial intermembrane space (IMS) and the IMS-localized RNASET2 is the enzyme that degrades the RNAs. This provides a new paradigm for understanding mitochondrial RNA metabolism and transport.
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Affiliation(s)
- Peipei Liu
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jinliang Huang
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Qian Zheng
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Leiming Xie
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xinping Lu
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jie Jin
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Geng Wang
- MOE Key laboratory of Bioinformatics, Cell Biology and Development Center, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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41
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Matilainen S, Carroll CJ, Richter U, Euro L, Pohjanpelto M, Paetau A, Isohanni P, Suomalainen A. Defective mitochondrial RNA processing due to PNPT1 variants causes Leigh syndrome. Hum Mol Genet 2017. [DOI: 10.1093/hmg/ddx221] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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42
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Bruni F, Lightowlers RN, Chrzanowska-Lightowlers ZM. Human mitochondrial nucleases. FEBS J 2017; 284:1767-1777. [PMID: 27926991 PMCID: PMC5484287 DOI: 10.1111/febs.13981] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 11/22/2016] [Accepted: 11/30/2016] [Indexed: 12/26/2022]
Abstract
Mitochondria are cytosolic organelles that have many essential roles including ATP production via oxidative phosphorylation, apoptosis, iron‐sulfur cluster biogenesis, heme and steroid synthesis, calcium homeostasis, and regulation of cellular redox state. One of the unique features of these organelles is the presence of an extrachromosomal mitochondrial genome (mtDNA), together with all the machinery required to replicate and transcribe mtDNA. The accurate maintenance of mitochondrial gene expression is essential for correct organellar metabolism, and is in part dependent on the levels of mtDNA and mtRNA, which are regulated by balancing synthesis against degradation. It is clear that although a number of mitochondrial nucleases have been identified, not all those responsible for the degradation of DNA or RNA have been characterized. Recent investigations, however, have revealed the contribution that mutations in the genes coding for these enzymes has made to causing pathogenic mitochondrial diseases.
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Affiliation(s)
- Francesco Bruni
- The Wellcome Trust Centre for Mitochondrial Research, The Medical School, Newcastle University, UK
| | - Robert N Lightowlers
- The Wellcome Trust Centre for Mitochondrial Research, The Medical School, Newcastle University, UK
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43
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Codipilly DC, Gavrilova RH, Tangalos EG. De novo 2p16.1 microdeletion with metastatic esophageal adenocarcinoma. BMJ Case Rep 2017; 2017:bcr-2016-218016. [PMID: 28108439 DOI: 10.1136/bcr-2016-218016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Microdeletions involving chromosome 2p15-16.1 are a rare genetic abnormality and have been reported in 18 separate patients, mainly children, since 2007. This microdeletion syndrome is characterised by a heterogeneous expression of intellectual impairment, dysmorphic facies, musculoskeletal abnormalities and potential neurodevelopmental anomalies. We report the first case of natural progression in an adult patient who died at a young age of metastatic esophageal adenocarcinoma. Important learning points include the variable phenotypic expression of this microdeletion syndrome and the fact that clinicians must be thorough in investigating objective discrepancies in patients who cannot endorse classical symptoms.
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Affiliation(s)
- Don Chamil Codipilly
- Department of Internal Medicine, Mayo Clinic Minnesota, Rochester, Minnesota, USA
| | - Ralitza H Gavrilova
- Department of Clinical Genomics and Neurology, Mayo Clinic Minnesota, Rochester, Minnesota, USA
| | - Eric G Tangalos
- Department of Primary Care Internal Medicine, Mayo Clinic Minnesota, Rochester, Minnesota, USA
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Whole-exome sequencing identifies novel variants in PNPT1 causing oxidative phosphorylation defects and severe multisystem disease. Eur J Hum Genet 2016; 25:79-84. [PMID: 27759031 DOI: 10.1038/ejhg.2016.128] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 08/10/2016] [Accepted: 08/23/2016] [Indexed: 11/08/2022] Open
Abstract
Recent advances in next-generation sequencing strategies have led to the discovery of many novel disease genes. We describe here a non-consanguineous family with two affected boys presenting with early onset of severe axonal neuropathy, optic atrophy, intellectual disability, auditory neuropathy and chronic respiratory and gut disturbances. Whole-exome sequencing (WES) was performed on all family members and we identified compound heterozygous variants (c.[760C>A];[1528G>C];p.[(Gln254Lys);(Ala510Pro)] in the polyribonucleotide nucleotidyltransferase 1 (PNPT1) gene in both affected individuals. PNPT1 encodes the polynucleotide phosphorylase (PNPase) protein, which is involved in the transport of small RNAs into the mitochondria. These RNAs are involved in the mitochondrial translation machinery, responsible for the synthesis of mitochondrially encoded subunits of the oxidative phosphorylation (OXPHOS) complexes. Both PNPT1 variants are within highly conserved regions and predicted to be damaging. These variants resulted in quaternary defects in the PNPase protein and a clear reduction in protein and mRNA expression of PNPT1 in patient fibroblasts compared with control cells. Protein analysis of the OXPHOS complexes showed a significant reduction in complex I (CI), complex III (CIII) and complex IV (CIV). Enzyme activity of CI and CIV was clearly reduced in patient fibroblasts compared with controls along with a 33% reduction in total mitochondrial protein synthesis. In vitro rescue experiments, using exogenous expression of wild-type PNPT1 in patient fibroblasts, ameliorated the deficiencies in the OXPHOS complex protein expression, supporting the likely pathogenicity of these variants and the importance of WES in efficiently identifying rare genetic disease genes.
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45
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Metodiev M, Thompson K, Alston C, Morris A, He L, Assouline Z, Rio M, Bahi-Buisson N, Pyle A, Griffin H, Siira S, Filipovska A, Munnich A, Chinnery P, McFarland R, Rötig A, Taylor R. Recessive Mutations in TRMT10C Cause Defects in Mitochondrial RNA Processing and Multiple Respiratory Chain Deficiencies. Am J Hum Genet 2016; 98:993-1000. [PMID: 27132592 PMCID: PMC4863561 DOI: 10.1016/j.ajhg.2016.03.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/14/2016] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial disorders are clinically and genetically diverse, with mutations in mitochondrial or nuclear genes able to cause defects in mitochondrial gene expression. Recently, mutations in several genes encoding factors involved in mt-tRNA processing have been identified to cause mitochondrial disease. Using whole-exome sequencing, we identified mutations in TRMT10C (encoding the mitochondrial RNase P protein 1 [MRPP1]) in two unrelated individuals who presented at birth with lactic acidosis, hypotonia, feeding difficulties, and deafness. Both individuals died at 5 months after respiratory failure. MRPP1, along with MRPP2 and MRPP3, form the mitochondrial ribonuclease P (mt-RNase P) complex that cleaves the 5′ ends of mt-tRNAs from polycistronic precursor transcripts. Additionally, a stable complex of MRPP1 and MRPP2 has m1R9 methyltransferase activity, which methylates mt-tRNAs at position 9 and is vital for folding mt-tRNAs into their correct tertiary structures. Analyses of fibroblasts from affected individuals harboring TRMT10C missense variants revealed decreased protein levels of MRPP1 and an increase in mt-RNA precursors indicative of impaired mt-RNA processing and defective mitochondrial protein synthesis. The pathogenicity of the detected variants—compound heterozygous c.542G>T (p.Arg181Leu) and c.814A>G (p.Thr272Ala) changes in subject 1 and a homozygous c.542G>T (p.Arg181Leu) variant in subject 2—was validated by the functional rescue of mt-RNA processing and mitochondrial protein synthesis defects after lentiviral transduction of wild-type TRMT10C. Our study suggests that these variants affect MRPP1 protein stability and mt-tRNA processing without affecting m1R9 methyltransferase activity, identifying mutations in TRMT10C as a cause of mitochondrial disease and highlighting the importance of RNA processing for correct mitochondrial function.
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46
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Min-Wen JC, Jun-Hao ET, Shyh-Chang N. Stem cell mitochondria during aging. Semin Cell Dev Biol 2016; 52:110-8. [PMID: 26851627 DOI: 10.1016/j.semcdb.2016.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 01/28/2016] [Accepted: 02/01/2016] [Indexed: 01/06/2023]
Abstract
Mitochondria are the central hubs of cellular metabolism, equipped with their own mitochondrial DNA (mtDNA) blueprints to direct part of the programming of mitochondrial oxidative metabolism and thus reactive oxygen species (ROS) levels. In stem cells, many stem cell factors governing the intricate balance between self-renewal and differentiation have been found to directly regulate mitochondrial processes to control stem cell behaviors during tissue regeneration and aging. Moreover, numerous nutrient-sensitive signaling pathways controlling organismal longevity in an evolutionarily conserved fashion also influence stem cell-mediated tissue homeostasis during aging via regulation of stem cell mitochondria. At the genomic level, it has been demonstrated that heritable mtDNA mutations and variants affect mammalian stem cell homeostasis and influence the risk for human degenerative diseases during aging. Because such a multitude of stem cell factors and signaling pathways ultimately converge on the mitochondria as the primary mechanism to modulate cellular and organismal longevity, it would be most efficacious to develop technologies to therapeutically target and direct mitochondrial repair in stem cells, as a unified strategy to combat aging-related degenerative diseases in the future.
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Affiliation(s)
- Jason Chua Min-Wen
- Stem Cell & Regenerative Biology, Genome Institute of Singapore, 60 Biopolis St, S138672, Singapore
| | - Elwin Tan Jun-Hao
- Stem Cell & Regenerative Biology, Genome Institute of Singapore, 60 Biopolis St, S138672, Singapore
| | - Ng Shyh-Chang
- Stem Cell & Regenerative Biology, Genome Institute of Singapore, 60 Biopolis St, S138672, Singapore.
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47
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Abstract
Methods of in vivo visualization and manipulation of mitochondrial genetic machinery are limited due to the need to surpass not only the cytoplasmic membrane but also two mitochondrial membranes. Here, we employ the matrix-addressing sequence of mitochondrial ribosomal 5S-rRNA (termed MAM), which is naturally imported into mammalian mitochondria, to construct an import system for in vivo targeting of mitochondrial (mt) DNA or mtRNA, in order to provide fluorescence hybridization of the desired sequences.
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Affiliation(s)
- Jaroslav Zelenka
- Department No. 75, Membrane Transprot Biophysics, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1084, Prague 4, 14220, Czech Republic
| | - Petr Ježek
- Department No. 75, Membrane Transprot Biophysics, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1084, Prague 4, 14220, Czech Republic.
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48
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Khaw SL, Min-Wen C, Koh CG, Lim B, Shyh-Chang N. Oocyte Factors Suppress Mitochondrial Polynucleotide Phosphorylase to Remodel the Metabolome and Enhance Reprogramming. Cell Rep 2015; 12:1080-8. [PMID: 26257174 DOI: 10.1016/j.celrep.2015.07.032] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/09/2015] [Accepted: 07/15/2015] [Indexed: 11/15/2022] Open
Abstract
Oocyte factors not only drive somatic cell nuclear transfer reprogramming but also augment the efficiency and quality of induced pluripotent stem cell (iPSC) reprogramming. Here, we show that the oocyte-enriched factors Tcl1 and Tcl1b1 significantly enhance reprogramming efficiency. Clonal analysis of pluripotency biomarkers further show that the Tcl1 oocyte factors improve the quality of reprogramming. Mechanistically, we find that the enhancement effect of Tcl1b1 depends on Akt, one of its putative targets. In contrast, Tcl1 suppresses the mitochondrial polynucleotide phosphorylase (PnPase) to promote reprogramming. Knockdown of PnPase rescues the inhibitory effect from Tcl1 knockdown during reprogramming, whereas PnPase overexpression abrogates the enhancement from Tcl1 overexpression. We further demonstrate that Tcl1 suppresses PnPase's mitochondrial localization to inhibit mitochondrial biogenesis and oxidation phosphorylation, thus remodeling the metabolome. Hence, we identified the Tcl1-PnPase pathway as a critical mitochondrial switch during reprogramming.
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Affiliation(s)
- Swea-Ling Khaw
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, Singapore 138672, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Chua Min-Wen
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Cheng-Gee Koh
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore.
| | - Bing Lim
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Ng Shyh-Chang
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, Singapore 138672, Singapore.
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49
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Mayr JA, Haack TB, Freisinger P, Karall D, Makowski C, Koch J, Feichtinger RG, Zimmermann FA, Rolinski B, Ahting U, Meitinger T, Prokisch H, Sperl W. Spectrum of combined respiratory chain defects. J Inherit Metab Dis 2015; 38:629-40. [PMID: 25778941 PMCID: PMC4493854 DOI: 10.1007/s10545-015-9831-y] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/20/2015] [Accepted: 02/23/2015] [Indexed: 01/22/2023]
Abstract
Inherited disorders of mitochondrial energy metabolism form a large and heterogeneous group of metabolic diseases. More than 250 gene defects have been reported to date and this number continues to grow. Mitochondrial diseases can be grouped into (1) disorders of oxidative phosphorylation (OXPHOS) subunits and their assembly factors, (2) defects of mitochondrial DNA, RNA and protein synthesis, (3) defects in the substrate-generating upstream reactions of OXPHOS, (4) defects in relevant cofactors and (5) defects in mitochondrial homeostasis. Deficiency of more than one respiratory chain enzyme is a common finding. Combined defects are found in 49 % of the known disease-causing genes of mitochondrial energy metabolism and in 57 % of patients with OXPHOS defects identified in our diagnostic centre. Combined defects of complexes I, III, IV and V are typically due to deficiency of mitochondrial DNA replication, RNA metabolism or translation. Defects in cofactors can result in combined defects of various combinations, and defects of mitochondrial homeostasis can result in a generalised decrease of all OXPHOS enzymes. Noteworthy, identification of combined defects can be complicated by different degrees of severity of each affected enzyme. Furthermore, even defects of single respiratory chain enzymes can result in combined defects due to aberrant formation of respiratory chain supercomplexes. Combined OXPHOS defects have a great variety of clinical manifestations in terms of onset, course severity and tissue involvement. They can present as classical encephalomyopathy but also with hepatopathy, nephropathy, haematologic findings and Perrault syndrome in a subset of disorders.
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Affiliation(s)
- Johannes A Mayr
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, Salzburg, 5020, Austria,
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50
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Van Haute L, Pearce SF, Powell CA, D’Souza AR, Nicholls TJ, Minczuk M. Mitochondrial transcript maturation and its disorders. J Inherit Metab Dis 2015; 38:655-80. [PMID: 26016801 PMCID: PMC4493943 DOI: 10.1007/s10545-015-9859-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/27/2015] [Accepted: 04/29/2015] [Indexed: 11/03/2022]
Abstract
Mitochondrial respiratory chain deficiencies exhibit a wide spectrum of clinical presentations owing to defective mitochondrial energy production through oxidative phosphorylation. These defects can be caused by either mutations in the mitochondrial DNA (mtDNA) or mutations in nuclear genes coding for mitochondrially-targeted proteins. The underlying pathomechanisms can affect numerous pathways involved in mitochondrial biology including expression of mtDNA-encoded genes. Expression of the mitochondrial genes is extensively regulated at the post-transcriptional stage and entails nucleolytic cleavage of precursor RNAs, RNA nucleotide modifications, RNA polyadenylation, RNA quality and stability control. These processes ensure proper mitochondrial RNA (mtRNA) function, and are regulated by dedicated, nuclear-encoded enzymes. Recent growing evidence suggests that mutations in these nuclear genes, leading to incorrect maturation of RNAs, are a cause of human mitochondrial disease. Additionally, mutations in mtDNA-encoded genes may also affect RNA maturation and are frequently associated with human disease. We review the current knowledge on a subset of nuclear-encoded genes coding for proteins involved in mitochondrial RNA maturation, for which genetic variants impacting upon mitochondrial pathophysiology have been reported. Also, primary pathological mtDNA mutations with recognised effects upon RNA processing are described.
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Affiliation(s)
| | - Sarah F. Pearce
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
| | | | - Aaron R. D’Souza
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
| | - Thomas J. Nicholls
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
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