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Da Costa L, Mohandas N, David-NGuyen L, Platon J, Marie I, O'Donohue MF, Leblanc T, Gleizes PE. Diamond-Blackfan anemia, the archetype of ribosomopathy: How distinct is it from the other constitutional ribosomopathies? Blood Cells Mol Dis 2024:102838. [PMID: 38413287 DOI: 10.1016/j.bcmd.2024.102838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/16/2024] [Accepted: 02/16/2024] [Indexed: 02/29/2024]
Abstract
Diamond-Blackfan anemia (DBA) was the first ribosomopathy described in humans. DBA is a congenital hypoplastic anemia, characterized by macrocytic aregenerative anemia, manifesting by differentiation blockage between the BFU-e/CFU-e developmental erythroid progenitor stages. In 50 % of the DBA cases, various malformations are noted. Strikingly, for a hematological disease with a relative erythroid tropism, DBA is due to ribosomal haploinsufficiency in 24 different ribosomal protein (RP) genes. A few other genes have been described in DBA-like disorders, but they do not fit into the classical DBA phenotype (Sankaran et al., 2012; van Dooijeweert et al., 2022; Toki et al., 2018; Kim et al., 2017 [1-4]). Haploinsufficiency in a RP gene leads to defective ribosomal RNA (rRNA) maturation, which is a hallmark of DBA. However, the mechanistic understandings of the erythroid tropism defect in DBA are still to be fully defined. Erythroid defect in DBA has been recently been linked in a non-exclusive manner to a number of mechanisms that include: 1) a defect in translation, in particular for the GATA1 erythroid gene; 2) a deficit of HSP70, the GATA1 chaperone, and 3) free heme toxicity. In addition, p53 activation in response to ribosomal stress is involved in DBA pathophysiology. The DBA phenotype may thus result from the combined contributions of various actors, which may explain the heterogenous phenotypes observed in DBA patients, even within the same family.
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Affiliation(s)
- L Da Costa
- Service d'Hématologie Biologique (Hematology Diagnostic Lab), AP-HP, Hôpital Bicêtre, F-94270 Le Kremlin-Bicêtre, France; University of Paris Saclay, F-94270 Le Kremlin-Bicêtre, France; University of Paris Cité, F-75010 Paris, France; University of Picardie Jules Verne, F-80000 Amiens, France; Inserm U1170, IGR, F-94805 Villejuif/HEMATIM UR4666, F-80000 Amiens, France; Laboratory of Excellence for Red Cells, LABEX GR-Ex, F-75015 Paris, France.
| | | | - Ludivine David-NGuyen
- Service d'Hématologie Biologique (Hematology Diagnostic Lab), AP-HP, Hôpital Bicêtre, F-94270 Le Kremlin-Bicêtre, France
| | - Jessica Platon
- Inserm U1170, IGR, F-94805 Villejuif/HEMATIM UR4666, F-80000 Amiens, France
| | - Isabelle Marie
- Service d'Hématologie Biologique (Hematology Diagnostic Lab), AP-HP, Hôpital Bicêtre, F-94270 Le Kremlin-Bicêtre, France
| | - Marie Françoise O'Donohue
- Molecular, Cellular and Developmental biology department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Thierry Leblanc
- Service d'immuno-hématologie pédiatrique, Hôpital Robert-Debré, F-75019 Paris, France
| | - Pierre-Emmanuel Gleizes
- Molecular, Cellular and Developmental biology department (MCD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
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2
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Batista LFZ, Dokal I, Parker R. Telomere biology disorders: time for moving towards the clinic? Trends Mol Med 2022; 28:882-891. [PMID: 36057525 PMCID: PMC9509473 DOI: 10.1016/j.molmed.2022.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 11/19/2022]
Abstract
Telomere biology disorders (TBDs) are a group of rare diseases caused by mutations that impair telomere maintenance. Mutations that cause reduced levels of TERC/hTR, the telomerase RNA component, are found in most TBD patients and include loss-of-function mutations in hTR itself, in hTR-binding proteins [NOP10, NHP2, NAF1, ZCCHC8, and dyskerin (DKC1)], and in proteins required for hTR processing (PARN). These patients show diverse clinical presentations that most commonly include bone marrow failure (BMF)/aplastic anemia (AA), pulmonary fibrosis, and liver cirrhosis. There are no curative therapies for TBD patients. An understanding of hTR biogenesis, maturation, and degradation has identified pathways and pharmacological agents targeting the poly(A) polymerase PAPD5, which adds 3'-oligoadenosine tails to hTR to promote hTR degradation, and TGS1, which modifies the 5'-cap structure of hTR to enhance degradation, as possible therapeutic approaches. Critical next steps will be clinical trials to establish the effectiveness and potential side effects of these compounds in TBD patients.
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Affiliation(s)
- Luis F Z Batista
- Department of Medicine, Washington University in St. Louis, St. Louis, MO, USA; Center for Genome Integrity, Washington University in St. Louis, St. Louis, MO, USA; Center of Regenerative Medicine, Washington University in St. Louis, St. Louis, MO, USA.
| | - Inderjeet Dokal
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
| | - Roy Parker
- Department of Biochemistry and Biofrontiers Instiute, University of Colorado, Boulder, CO, USA; Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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3
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Tummala H, Walne A, Buccafusca R, Alnajar J, Szabo A, Robinson P, McConkie-Rosell A, Wilson M, Crowley S, Kinsler V, Ewins AM, Madapura PM, Patel M, Pontikos N, Codd V, Vulliamy T, Dokal I. Germline thymidylate synthase deficiency impacts nucleotide metabolism and causes dyskeratosis congenita. Am J Hum Genet 2022; 109:1472-1483. [PMID: 35931051 PMCID: PMC9388389 DOI: 10.1016/j.ajhg.2022.06.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/23/2022] [Indexed: 11/19/2022] Open
Abstract
Dyskeratosis congenita (DC) is an inherited bone-marrow-failure disorder characterized by a triad of mucocutaneous features that include abnormal skin pigmentation, nail dystrophy, and oral leucoplakia. Despite the identification of several genetic variants that cause DC, a significant proportion of probands remain without a molecular diagnosis. In a cohort of eight independent DC-affected families, we have identified a remarkable series of heterozygous germline variants in the gene encoding thymidylate synthase (TYMS). Although the inheritance appeared to be autosomal recessive, one parent in each family had a wild-type TYMS coding sequence. Targeted genomic sequencing identified a specific haplotype and rare variants in the naturally occurring TYMS antisense regulator ENOSF1 (enolase super family 1) inherited from the other parent. Lymphoblastoid cells from affected probands have severe TYMS deficiency, altered cellular deoxyribonucleotide triphosphate pools, and hypersensitivity to the TYMS-specific inhibitor 5-fluorouracil. These defects in the nucleotide metabolism pathway resulted in genotoxic stress, defective transcription, and abnormal telomere maintenance. Gene-rescue studies in cells from affected probands revealed that post-transcriptional epistatic silencing of TYMS is occurring via elevated ENOSF1. These cell and molecular abnormalities generated by the combination of germline digenic variants at the TYMS-ENOSF1 locus represent a unique pathogenetic pathway for DC causation in these affected individuals, whereas the parents who are carriers of either of these variants in a singular fashion remain unaffected.
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Affiliation(s)
- Hemanth Tummala
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK.
| | - Amanda Walne
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Roberto Buccafusca
- School of Physical and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS, UK
| | - Jenna Alnajar
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Anita Szabo
- Institute of Ophthalmology, Faculty of Brain Sciences, University College London, 11-43 Bath St, London EC1V 9EL, UK
| | - Peter Robinson
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Dr., Farmington, CT 06032, USA
| | | | - Meredith Wilson
- Department of Clinical Genetics, The Children's Hospital at Westmead, Sydney, Australia
| | - Suzanne Crowley
- Department of Paediatrics, St George's Healthcare NHS Trust, London, UK
| | - Veronica Kinsler
- Department of Paediatric Dermatology, Great Ormond Street Hospital, The Francis Crick Institute, London, UK
| | - Anna-Maria Ewins
- Haematology/Oncology Department, Royal Hospital for Sick Children, Glasgow, UK
| | - Pradeepa M Madapura
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Manthan Patel
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Nikolas Pontikos
- Institute of Ophthalmology, Faculty of Brain Sciences, University College London, 11-43 Bath St, London EC1V 9EL, UK
| | - Veryan Codd
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Tom Vulliamy
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Inderjeet Dokal
- Genomics and Child Health, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK; Barts Health NHS Trust, London, UK
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4
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Vertecchi E, Rizzo A, Salvati E. Telomere Targeting Approaches in Cancer: Beyond Length Maintenance. Int J Mol Sci 2022; 23:ijms23073784. [PMID: 35409143 PMCID: PMC8998427 DOI: 10.3390/ijms23073784] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 12/19/2022] Open
Abstract
Telomeres are crucial structures that preserve genome stability. Their progressive erosion over numerous DNA duplications determines the senescence of cells and organisms. As telomere length homeostasis is critical for cancer development, nowadays, telomere maintenance mechanisms are established targets in cancer treatment. Besides telomere elongation, telomere dysfunction impinges on intracellular signaling pathways, in particular DNA damage signaling and repair, affecting cancer cell survival and proliferation. This review summarizes and discusses recent findings in anticancer drug development targeting different “telosome” components.
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Affiliation(s)
- Eleonora Vertecchi
- Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy, c/o Department of Biology and Biotechnology, Sapienza University of Rome, Via degli Apuli 4, 00185 Rome, Italy;
| | - Angela Rizzo
- Oncogenomic and Epigenetic Unit, IRCCS Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144 Rome, Italy;
| | - Erica Salvati
- Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy, c/o Department of Biology and Biotechnology, Sapienza University of Rome, Via degli Apuli 4, 00185 Rome, Italy;
- Correspondence:
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5
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AlSabbagh MM. Dyskeratosis congenita: ein Literaturüberblick. J Dtsch Dermatol Ges 2020; 18:943-968. [PMID: 32985809 DOI: 10.1111/ddg.14268_g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/29/2020] [Indexed: 02/06/2023]
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AlSabbagh MM. Dyskeratosis congenita: a literature review. J Dtsch Dermatol Ges 2020; 18:943-967. [PMID: 32930426 DOI: 10.1111/ddg.14268] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/29/2020] [Indexed: 12/26/2022]
Abstract
Dyskeratosis congenita is a rare hereditary disease that occurs predominantly in males and manifests clinically as the classic triad of reticulate hyperpigmentation, nail dystrophy and leukoplakia. It increases the risk of malignancy and other potentially lethal complications such as bone marrow failure, lung and liver diseases. Mutations in 19 genes are associated with dyskeratosis congenita, and a fifth of the pathogenic mutations are found in DKC1, the gene coding for dyskerin. This review aims to address the clinical and genetic aspects of the disease.
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7
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Mangaonkar AA, Patnaik MM. Hereditary Predisposition to Hematopoietic Neoplasms: When Bloodline Matters for Blood Cancers. Mayo Clin Proc 2020; 95:1482-1498. [PMID: 32571604 DOI: 10.1016/j.mayocp.2019.12.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/23/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023]
Abstract
With the advent of precision genomics, hereditary predisposition to hematopoietic neoplasms- collectively known as hereditary predisposition syndromes (HPS)-are being increasingly recognized in clinical practice. Familial clustering was first observed in patients with leukemia, which led to the identification of several germline variants, such as RUNX1, CEBPA, GATA2, ANKRD26, DDX41, and ETV6, among others, now established as HPS, with tendency to develop myeloid neoplasms. However, evidence for hereditary predisposition is also apparent in lymphoid and plasma--cell neoplasms, with recent discoveries of germline variants in genes such as IKZF1, SH2B3, PAX5 (familial acute lymphoblastic leukemia), and KDM1A/LSD1 (familial multiple myeloma). Specific inherited bone marrow failure syndromes-such as GATA2 haploinsufficiency syndromes, short telomere syndromes, Shwachman-Diamond syndrome, Diamond-Blackfan anemia, severe congenital neutropenia, and familial thrombocytopenias-also have an increased predisposition to develop myeloid neoplasms, whereas inherited immune deficiency syndromes, such as ataxia-telangiectasia, Bloom syndrome, Wiskott Aldrich syndrome, and Bruton agammaglobulinemia, are associated with an increased risk for lymphoid neoplasms. Timely recognition of HPS is critical to ensure safe choice of donors and/or conditioning-regimen intensity for allogeneic hematopoietic stem-cell transplantation and to enable direction of appropriate genomics-driven personalized therapies. The purpose of this review is to provide a comprehensive overview of HPS and serve as a useful reference for clinicians to recognize relevant signs and symptoms among patients to enable timely screening and referrals to pursue germline assessment. In addition, we also discuss our institutional approach toward identification of HPS and offer a stepwise diagnostic and management algorithm.
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Affiliation(s)
| | - Mrinal M Patnaik
- Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN.
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8
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Homozygous OB-fold variants in telomere protein TPP1 are associated with dyskeratosis congenita-like phenotypes. Blood 2018; 132:1349-1353. [PMID: 30064976 DOI: 10.1182/blood-2018-03-837799] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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9
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Mangaonkar AA, Patnaik MM. Short Telomere Syndromes in Clinical Practice: Bridging Bench and Bedside. Mayo Clin Proc 2018; 93:904-916. [PMID: 29804726 PMCID: PMC6035054 DOI: 10.1016/j.mayocp.2018.03.020] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/19/2018] [Indexed: 10/16/2022]
Abstract
Short telomere syndromes (STSs) are accelerated aging syndromes often caused by inheritable gene mutations resulting in decreased telomere lengths. Consequently, organ systems with increased cell turnover, such as the skin, bone marrow, lungs, and gastrointestinal tract, are commonly affected. Owing to diverse clinical presentations, STSs pose a diagnostic challenge, with bone marrow failure and idiopathic pulmonary fibrosis being frequent manifestations, occurring in association with gene mutations involving DKC1 (for expansion of gene symbols, use search tool at www.genenames.org), TERT, TERC, and others. Inherited STSs demonstrate genetic anticipation, occurring at an earlier age with more severe manifestations in the affected progeny. Telomere lengths can be assessed in peripheral blood granulocytes and lymphocytes using a sensitive technique called flow cytometry-fluorescence in situ hybridization, and mutational analysis can be performed using next-generation sequencing assays. In approximately 40% of patients with shortened telomere lengths, gene mutations cannot be identified due to the fact that all STS-associated genes have not yet been defined or due to alternative mechanisms of telomere shortening. Danazol, an anabolic steroid, has been associated with hematologic responses in patients with STSs and associated bone marrow failure; however, its reported ability to increase telomerase activity and reduce telomere attrition needs further elucidation. Organ transplant is reserved for patients with end-organ failure and is associated with substantial morbidity and mortality. Herein, we summarize the clinical and laboratory characteristics of STSs and offer a stepwise approach to diagnose and manage complications in affected patients.
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Affiliation(s)
| | - Mrinal M Patnaik
- Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN.
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10
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Ibáñez-Cabellos JS, Pérez-Machado G, Seco-Cervera M, Berenguer-Pascual E, García-Giménez JL, Pallardó FV. Acute telomerase components depletion triggers oxidative stress as an early event previous to telomeric shortening. Redox Biol 2017; 14:398-408. [PMID: 29055871 PMCID: PMC5650655 DOI: 10.1016/j.redox.2017.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/04/2017] [Accepted: 10/05/2017] [Indexed: 01/13/2023] Open
Abstract
Loss of function of dyskerin (DKC1), NOP10 and TIN2 are responsible for different inheritance patterns of Dyskeratosis congenita (DC; ORPHA1775). They are key components of telomerase (DKC1 and NOP10) and shelterin (TIN2), and play an important role in telomere homeostasis. They participate in several fundamental cellular processes by contributing to Dyskeratosis congenita through mechanisms that are not fully understood. Presence of oxidative stress was postulated to result from telomerase ablation. However, the resulting disturbed redox status can promote telomere attrition by generating a vicious circle, which promotes cellular senescence. This fact prompted us to study if acute loss of DKC1, NOP10 and TINF2 can promote redox disequilibrium as an early event when telomere shortening has not yet taken place. We generated siRNA-mediated (DKC1, NOP10 and TINF2) cell lines by RNA interference, which was confirmed by mRNA and protein expression analyses. No telomere shortening occurred in any silenced cell line. Depletion of H/ACA ribonucleoproteins DKC1 and NOP10 diminished telomerase activity via TERC down-regulation, and produced alterations in pseudouridylation and ribosomal biogenesis. An increase in the GSSG/GSH ratio, carbonylated proteins and oxidized peroxiredoxin-6 was observed, in addition to MnSOD and TRX1 overexpression in the siRNA DC cells. Likewise, high PARylation levels and high PARP1 protein expression were detected. In contrast, the silenced TINF2 cells did not alter any evaluated oxidative stress marker. Altogether these findings lead us to conclude that loss of DKC1 and NOP10 functions induces oxidative stress in a telomere shortening independent manner. Transient silencing of DKC1 and NOP10 genes produce oxidative stress. Cells depleted of DKC1 and NOP10 are susceptible to DNA damage. Acute DKC1 and NOP10 depletion disrupts RNA maturation. Oxidative stress is an early event previous to telomere shortening.
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Affiliation(s)
- José Santiago Ibáñez-Cabellos
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Institute of Health Carlos III, Valencia, Spain; Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
| | - Giselle Pérez-Machado
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
| | - Marta Seco-Cervera
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Institute of Health Carlos III, Valencia, Spain; Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
| | - Ester Berenguer-Pascual
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain.
| | - José Luis García-Giménez
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Institute of Health Carlos III, Valencia, Spain; Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
| | - Federico V Pallardó
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Institute of Health Carlos III, Valencia, Spain; Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
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11
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Abstract
Chromosome ends are complex structures, which require a panel of factors for their elongation, replication, and protection. We describe here the mechanics of mammalian telomeres, dynamics and maintainance in relation to lamins. Multiple biochemical connections, including association of telomeres to the nuclear envelope and matrix, of telomeric proteins to lamins, and of lamin-associated proteins to chromosome ends, underline the interplay between lamins and telomeres. Paths toward senescence, such as defective telomere replication, altered heterochromatin organization, and impaired DNA repair, are common to lamins' and telomeres' dysfunction. The convergence of phenotypes can be interpreted through a model of dynamic, lamin-controlled functional platforms dedicated to the function of telomeres as fragile sites. The features of telomeropathies and laminopathies, and of animal models underline further overlapping aspects, including the alteration of stem cell compartments. We expect that future studies of basic biology and on aging will benefit from the analysis of this telomere-lamina interplay.
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Affiliation(s)
- Romina Burla
- a Dipartimento di Biologia e Biotecnologie "C. Darwin," Sapienza Università di Roma , Rome, Italy.,b Istituto di Biologia e Patologia Molecolari del CNR , Rome , Italy
| | - Mattia La Torre
- a Dipartimento di Biologia e Biotecnologie "C. Darwin," Sapienza Università di Roma , Rome, Italy
| | - Isabella Saggio
- a Dipartimento di Biologia e Biotecnologie "C. Darwin," Sapienza Università di Roma , Rome, Italy.,b Istituto di Biologia e Patologia Molecolari del CNR , Rome , Italy.,c Istituto Pasteur Fondazione Cenci Bolognetti , Rome , Italy
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12
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Walne AJ, Collopy L, Cardoso S, Ellison A, Plagnol V, Albayrak C, Albayrak D, Kilic SS, Patıroglu T, Akar H, Godfrey K, Carter T, Marafie M, Vora A, Sundin M, Vulliamy T, Tummala H, Dokal I. Marked overlap of four genetic syndromes with dyskeratosis congenita confounds clinical diagnosis. Haematologica 2016; 101:1180-1189. [PMID: 27612988 DOI: 10.3324/haematol.2016.147769] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/21/2016] [Indexed: 11/09/2022] Open
Abstract
Dyskeratosis congenita is a highly pleotropic genetic disorder. This heterogeneity can lead to difficulties in making an accurate diagnosis and delays in appropriate management. The aim of this study was to determine the underlying genetic basis in patients presenting with features of dyskeratosis congenita and who were negative for mutations in the classical dyskeratosis congenita genes. By whole exome and targeted sequencing, we identified biallelic variants in genes that are not associated with dyskeratosis congenita in 17 individuals from 12 families. Specifically, these were homozygous variants in USB1 (8 families), homozygous missense variants in GRHL2 (2 families) and identical compound heterozygous variants in LIG4 (2 families). All patients had multiple somatic features of dyskeratosis congenita but not the characteristic short telomeres. Our case series shows that biallelic variants in USB1, LIG4 and GRHL2, the genes mutated in poikiloderma with neutropenia, LIG4/Dubowitz syndrome and the recently recognized ectodermal dysplasia/short stature syndrome, respectively, cause features that overlap with dyskeratosis congenita. Strikingly, these genes also overlap in their biological function with the known dyskeratosis congenita genes that are implicated in telomere maintenance and DNA repair pathways. Collectively, these observations demonstrate the marked overlap of dyskeratosis congenita with four other genetic syndromes, confounding accurate diagnosis and subsequent management. This has important implications for establishing a genetic diagnosis when a new patient presents in the clinic. Patients with clinical features of dyskeratosis congenita need to have genetic analysis of USB1, LIG4 and GRHL2 in addition to the classical dyskeratosis congenita genes and telomere length measurements.
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Affiliation(s)
- Amanda J Walne
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Barts NHS Trust, London, UK
| | - Laura Collopy
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Barts NHS Trust, London, UK
| | - Shirleny Cardoso
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Barts NHS Trust, London, UK
| | - Alicia Ellison
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Barts NHS Trust, London, UK
| | | | - Canan Albayrak
- Department of Pediatric Hematology, Ondokuz Mayis University, Samsun, Turkey
| | - Davut Albayrak
- Department of Pediatric Hematology, Ondokuz Mayis University, Samsun, Turkey
| | | | - Turkan Patıroglu
- Department of Pediatric Immunology Erciyes University Medical Facility, Kayseri, Turkey
| | - Haluk Akar
- Department of Pediatric Immunology Erciyes University Medical Facility, Kayseri, Turkey
| | - Keith Godfrey
- Department of Pediatric Dermatology and NIHR Southampton Biomedical Research Center, University Hospital, Southampton and University of Southampton, UK
| | - Tina Carter
- Department of Oncology and Haematology, Princess Margaret Hospital, Perth, WA, Australia
| | - Makia Marafie
- Clinical Cancer and Community Genetics, Kuwait Medical Genetics Center, Al-Sabah Medical area, Kuwait
| | - Ajay Vora
- Department of Haematology, Sheffield Children's NHS foundation Trust, Sheffield, UK
| | - Mikael Sundin
- Section of Pediatric Hematology/Immunology/SCT, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden Division of Pediatrics, CLINTEC, Karolinska Institutet, Stockholm, Sweden
| | - Thomas Vulliamy
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Barts NHS Trust, London, UK
| | - Hemanth Tummala
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Barts NHS Trust, London, UK
| | - Inderjeet Dokal
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Barts NHS Trust, London, UK
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13
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Pereboeva L, Hubbard M, Goldman FD, Westin ER. Robust DNA Damage Response and Elevated Reactive Oxygen Species in TINF2-Mutated Dyskeratosis Congenita Cells. PLoS One 2016; 11:e0148793. [PMID: 26859482 PMCID: PMC4747510 DOI: 10.1371/journal.pone.0148793] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 01/22/2016] [Indexed: 12/13/2022] Open
Abstract
Dyskeratosis Congenita (DC) is an inherited multisystem premature aging disorder with characteristic skin and mucosal findings as well as a predisposition to cancer and bone marrow failure. DC arises due to gene mutations associated with the telomerase complex or telomere maintenance, resulting in critically shortened telomeres. The pathogenesis of DC, as well as several congenital bone marrow failure (BMF) syndromes, converges on the DNA damage response (DDR) pathway and subsequent elevation of reactive oxygen species (ROS). Historically, DC patients have had poor outcomes following bone marrow transplantation (BMT), perhaps as a consequence of an underlying DNA hypersensitivity to cytotoxic agents. Previously, we demonstrated an activated DDR and increased ROS, augmented by chemotherapy and radiation, in somatic cells isolated from DC patients with a mutation in the RNA component of telomerase, TERC. The current study was undertaken to determine whether previous findings related to ROS and DDR in TERC patients’ cells could be extended to other DC mutations. Of particular interest was whether an antioxidant approach could counter increased ROS and decrease DC pathologies. To test this, we examined lymphocytes from DC patients from different DC mutations (TERT, TINF2, and TERC) for the presence of an active DDR and increased ROS. All DC mutations led to increased steady-state p53 (2-fold to 10-fold) and ROS (1.5-fold to 2-fold). Upon exposure to ionizing radiation (XRT), DC cells increased in both DDR and ROS to a significant degree. Exposing DC cells to hydrogen peroxide also revealed that DC cells maintain a significant oxidant burden compared to controls (1.5-fold to 3-fold). DC cell culture supplemented with N-acetylcysteine, or alternatively grown in low oxygen, afforded significant proliferative benefits (proliferation: maximum 2-fold increase; NAC: 5-fold p53 decrease; low oxygen: maximum 3.5-fold p53 decrease). Together, our data supports a mechanism whereby telomerase deficiency and subsequent shortened telomeres initiate a DDR and create a pro-oxidant environment, especially in cells carrying the TINF2 mutations. Finally, the ameliorative effects of antioxidants in vitro suggest this could translate to therapeutic benefits in DC patients.
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Affiliation(s)
- Larisa Pereboeva
- Department of Medicine, Division of Hematology Oncology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Meredith Hubbard
- Department of Pediatrics, Division of Hematology Oncology, University of Alabama, Birmingham, Alabama, United States of America
| | - Frederick D. Goldman
- Department of Pediatrics, Division of Hematology Oncology, University of Alabama, Birmingham, Alabama, United States of America
| | - Erik R. Westin
- Department of Pediatrics, Division of Hematology Oncology, University of Alabama, Birmingham, Alabama, United States of America
- * E-mail:
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14
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Lin P, Mobasher ME, Hakakian Y, Kakarla V, Naseem AF, Ziai H, Alawi F. Differential requirements for H/ACA ribonucleoprotein components in cell proliferation and response to DNA damage. Histochem Cell Biol 2015; 144:543-58. [PMID: 26265134 DOI: 10.1007/s00418-015-1359-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2015] [Indexed: 02/07/2023]
Abstract
H/ACA ribonucleoproteins (RNPs) are comprised of four conserved proteins, dyskerin, NHP2, NOP10, and GAR1, and a function-specifying, noncoding H/ACA RNA. H/ACA RNPs contribute to telomerase assembly and stabilization, and posttranscriptional processing of nascent ribosomal RNA and spliceosomal RNA. However, very little is known about the coordinated action of the four proteins in other biologic processes. As described herein, we observed a differential requirement for the proteins in cell proliferation and identified a possible reliance for these factors in regulation of specific DNA damage biomarkers. In particular, GAR1 expression was upregulated following exposure to all forms of genotoxic stress tested. In contrast, levels of the other proteins were either reduced or unaffected. Only GAR1 showed an altered subcellular localization with a shift from the nucleolus to the nucleoplasm after ultraviolet-C irradiation and doxorubicin treatments. Transient siRNA-mediated depletion of GAR1 and dyskerin arrested cell proliferation, whereas loss of either NHP2 or NOP10 had no effect. Finally, loss of dyskerin, GAR1, NHP2, and NOP10, respectively, limited the accumulation of DNA damage biomarkers. However, the individual responses were dependent upon the specific type of damage incurred. In general, loss of GAR1 had the most suppressive effect on the biomarkers tested. Since the specific responses to genotoxic stress, the contribution of each protein to cell proliferation, and the activation of DNA damage biomarkers were not equivalent, this suggests the possibility that at least some of the proteins, most notably GAR1, may potentially function independently of their respective roles within H/ACA RNP complexes.
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Affiliation(s)
- Ping Lin
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Levy Building - Room 328B, Philadelphia, PA, 19104, USA
| | - Maral E Mobasher
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Levy Building - Room 328B, Philadelphia, PA, 19104, USA
| | - Yasaman Hakakian
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Levy Building - Room 328B, Philadelphia, PA, 19104, USA
| | - Veena Kakarla
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Levy Building - Room 328B, Philadelphia, PA, 19104, USA
| | - Anum F Naseem
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Levy Building - Room 328B, Philadelphia, PA, 19104, USA
| | - Heliya Ziai
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Levy Building - Room 328B, Philadelphia, PA, 19104, USA
| | - Faizan Alawi
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 South 40th Street, Levy Building - Room 328B, Philadelphia, PA, 19104, USA.
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15
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Tummala H, Walne A, Collopy L, Cardoso S, de la Fuente J, Lawson S, Powell J, Cooper N, Foster A, Mohammed S, Plagnol V, Vulliamy T, Dokal I. Poly(A)-specific ribonuclease deficiency impacts telomere biology and causes dyskeratosis congenita. J Clin Invest 2015; 125:2151-60. [PMID: 25893599 DOI: 10.1172/jci78963] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 02/12/2015] [Indexed: 11/17/2022] Open
Abstract
Dyskeratosis congenita (DC) and related syndromes are inherited, life-threatening bone marrow (BM) failure disorders, and approximately 40% of cases are currently uncharacterized at the genetic level. Here, using whole exome sequencing (WES), we have identified biallelic mutations in the gene encoding poly(A)-specific ribonuclease (PARN) in 3 families with individuals exhibiting severe DC. PARN is an extensively characterized exonuclease with deadenylation activity that controls mRNA stability in part and therefore regulates expression of a large number of genes. The DC-associated mutations identified affect key domains within the protein, and evaluation of patient cells revealed reduced deadenylation activity. This deadenylation deficiency caused an early DNA damage response in terms of nuclear p53 regulation, cell-cycle arrest, and reduced cell viability upon UV treatment. Individuals with biallelic PARN mutations and PARN-depleted cells exhibited reduced RNA levels for several key genes that are associated with telomere biology, specifically TERC, DKC1, RTEL1, and TERF1. Moreover, PARN-deficient cells also possessed critically short telomeres. Collectively, these results identify a role for PARN in telomere maintenance and demonstrate that it is a disease-causing gene in a subset of patients with severe DC.
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16
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Fernández García MS, Teruya-Feldstein J. The diagnosis and treatment of dyskeratosis congenita: a review. J Blood Med 2014; 5:157-67. [PMID: 25170286 PMCID: PMC4145822 DOI: 10.2147/jbm.s47437] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Dyskeratosis congenita (DC) is an inherited bone marrow failure (BMF) syndrome characterized by the classic triad of abnormal skin pigmentation, nail dystrophy, and oral leukoplakia. However, patients usually develop BMF and are predisposed to cancer, with increased risk for squamous cell carcinoma and hematolymphoid neoplasms. DC is a disease of defective telomere maintenance and is heterogeneous at the genetic level. It can be inherited in X-linked, autosomal dominant, or autosomal recessive patterns. Mutations in at least ten telomere- and telomerase-associated genes have been described in DC. There are no targeted therapies for DC and patients usually die of BMF due to a deficient renewing capability of hematopoietic stem cells. Allogeneic hematopoietic stem cell transplantation is the only curative treatment for BMF.
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Affiliation(s)
- M Soledad Fernández García
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA ; Department of Pathology, Hospital Universitario Central de Asturias, Oviedo, Spain
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17
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Nakhoul H, Ke J, Zhou X, Liao W, Zeng SX, Lu H. Ribosomopathies: mechanisms of disease. PLASMATOLOGY 2014; 7:7-16. [PMID: 25512719 PMCID: PMC4251057 DOI: 10.4137/cmbd.s16952] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/03/2014] [Accepted: 07/16/2014] [Indexed: 01/05/2023]
Abstract
Ribosomopathies are diseases caused by alterations in the structure or function of ribosomal components. Progress in our understanding of the role of the ribosome in translational and transcriptional regulation has clarified the mechanisms of the ribosomopathies and the relationship between ribosomal dysfunction and other diseases, especially cancer. This review aims to discuss these topics with updated information.
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Affiliation(s)
- Hani Nakhoul
- Department of Biochemistry and Molecular Biology and Cancer Center, Tulane University, School of Medicine, New Orleans, Louisiana, LA, USA
| | - Jiangwei Ke
- Department of Biochemistry and Molecular Biology and Cancer Center, Tulane University, School of Medicine, New Orleans, Louisiana, LA, USA. ; Department of Laboratory Medicine, Jiangxi Children's Hospital, Nanchang, Jiangxi, China
| | - Xiang Zhou
- Department of Biochemistry and Molecular Biology and Cancer Center, Tulane University, School of Medicine, New Orleans, Louisiana, LA, USA
| | - Wenjuan Liao
- Department of Biochemistry and Molecular Biology and Cancer Center, Tulane University, School of Medicine, New Orleans, Louisiana, LA, USA
| | - Shelya X Zeng
- Department of Biochemistry and Molecular Biology and Cancer Center, Tulane University, School of Medicine, New Orleans, Louisiana, LA, USA
| | - Hua Lu
- Department of Biochemistry and Molecular Biology and Cancer Center, Tulane University, School of Medicine, New Orleans, Louisiana, LA, USA
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18
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Manguan-Garcia C, Pintado-Berninches L, Carrillo J, Machado-Pinilla R, Sastre L, Pérez-Quilis C, Esmoris I, Gimeno A, García-Giménez JL, Pallardó FV, Perona R. Expression of the genetic suppressor element 24.2 (GSE24.2) decreases DNA damage and oxidative stress in X-linked dyskeratosis congenita cells. PLoS One 2014; 9:e101424. [PMID: 24987982 PMCID: PMC4079255 DOI: 10.1371/journal.pone.0101424] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 06/06/2014] [Indexed: 01/10/2023] Open
Abstract
The predominant X-linked form of Dyskeratosis congenita results from mutations in DKC1, which encodes dyskerin, a protein required for ribosomal RNA modification that is also a component of the telomerase complex. We have previously found that expression of an internal fragment of dyskerin (GSE24.2) rescues telomerase activity in X-linked dyskeratosis congenita (X-DC) patient cells. Here we have found that an increased basal and induced DNA damage response occurred in X-DC cells in comparison with normal cells. DNA damage that is also localized in telomeres results in increased heterochromatin formation and senescence. Expression of a cDNA coding for GSE24.2 rescues both global and telomeric DNA damage. Furthermore, transfection of bacterial purified or a chemically synthesized GSE24.2 peptide is able to rescue basal DNA damage in X-DC cells. We have also observed an increase in oxidative stress in X-DC cells and expression of GSE24.2 was able to diminish it. Altogether our data indicated that supplying GSE24.2, either from a cDNA vector or as a peptide reduces the pathogenic effects of Dkc1 mutations and suggests a novel therapeutic approach.
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Affiliation(s)
- Cristina Manguan-Garcia
- Instituto de Investigaciones Biomédicas CSIC/UAM, Madrid, Spain
- CIBER de Enfermedades Raras, Valencia, Spain
| | | | - Jaime Carrillo
- Instituto de Investigaciones Biomédicas CSIC/UAM, Madrid, Spain
| | - Rosario Machado-Pinilla
- Instituto de Investigaciones Biomédicas CSIC/UAM, Madrid, Spain
- CIBER de Enfermedades Raras, Valencia, Spain
| | - Leandro Sastre
- Instituto de Investigaciones Biomédicas CSIC/UAM, Madrid, Spain
- CIBER de Enfermedades Raras, Valencia, Spain
| | - Carme Pérez-Quilis
- Biomedical Research Institute INCLIVA, Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain
| | - Isabel Esmoris
- Biomedical Research Institute INCLIVA, Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain
| | - Amparo Gimeno
- Biomedical Research Institute INCLIVA, Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain
| | - Jose Luis García-Giménez
- CIBER de Enfermedades Raras, Valencia, Spain
- Biomedical Research Institute INCLIVA, Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain
| | - Federico V. Pallardó
- CIBER de Enfermedades Raras, Valencia, Spain
- Biomedical Research Institute INCLIVA, Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain
| | - Rosario Perona
- Instituto de Investigaciones Biomédicas CSIC/UAM, Madrid, Spain
- CIBER de Enfermedades Raras, Valencia, Spain
- * E-mail:
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19
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Acute dyskerin depletion triggers cellular senescence and renders osteosarcoma cells resistant to genotoxic stress-induced apoptosis. Biochem Biophys Res Commun 2014; 446:1268-75. [PMID: 24690175 DOI: 10.1016/j.bbrc.2014.03.114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 03/22/2014] [Indexed: 01/02/2023]
Abstract
Dyskerin is a conserved, nucleolar RNA-binding protein implicated in an increasing array of fundamental cellular processes. Germline mutation in the dyskerin gene (DKC1) is the cause of X-linked dyskeratosis congenita (DC). Conversely, wild-type dyskerin is overexpressed in sporadic cancers, and high-levels may be associated with poor prognosis. It was previously reported that acute loss of dyskerin function via siRNA-mediated depletion slowed the proliferation of transformed cell lines. However, the mechanisms remained unclear. Using human U2OS osteosarcoma cells, we show that siRNA-mediated dyskerin depletion induced cellular senescence as evidenced by proliferative arrest, senescence-associated heterochromatinization and a senescence-associated molecular profile. Senescence can render cells resistant to apoptosis. Conversely, chromatin relaxation can reverse the repressive effects of senescence-associated heterochromatinization on apoptosis. To this end, genotoxic stress-induced apoptosis was suppressed in dyskerin-depleted cells. In contrast, agents that induce chromatin relaxation, including histone deacetylase inhibitors and the DNA intercalator chloroquine, sensitized dyskerin-depleted cells to apoptosis. Dyskerin is a core component of the telomerase complex and plays an important role in telomere homeostasis. Defective telomere maintenance resulting in premature senescence is thought to primarily underlie the pathogenesis of X-linked DC. Since U2OS cells are telomerase-negative, this leads us to conclude that loss of dyskerin function can also induce cellular senescence via mechanisms independent of telomere shortening.
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20
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Tummala H, Kirwan M, Walne AJ, Hossain U, Jackson N, Pondarre C, Plagnol V, Vulliamy T, Dokal I. ERCC6L2 mutations link a distinct bone-marrow-failure syndrome to DNA repair and mitochondrial function. Am J Hum Genet 2014; 94:246-56. [PMID: 24507776 PMCID: PMC3928664 DOI: 10.1016/j.ajhg.2014.01.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 01/10/2014] [Indexed: 10/25/2022] Open
Abstract
Exome sequencing was performed in three index cases with bone marrow failure and neurological dysfunction and whose parents are first-degree cousins. Homozygous truncating mutations were identified in ERCC6L2 in two of the individuals. Both of these mutations affect the subcellular localization and stability of ERCC6L2. We show here that knockdown of ERCC6L2 in human A549 cells significantly reduced their viability upon exposure to the DNA-damaging agents mitomycin C and Irofulven, but not etoposide and camptothecin, suggesting a role in nucleotide excision repair. ERCC6L2-knockdown cells also displayed H2AX phosphorylation, which significantly increased upon genotoxic stress, suggesting an early DNA-damage response. Intriguingly, ERCC6L2 was seen to translocate to the mitochondria and the nucleus in response to DNA damage, and ERCC6L2 knockdown induced intracellular reactive oxygen species (ROS). Treatment with the ROS scavenger N-acetyl cysteine attenuated the Irofulven-induced cytotoxicity in ERCC6L2-knockdown cells and abolished ERCCGL2 traffic to the mitochondria and nucleus in response to this DNA-damaging agent. Collectively, these observations identify a distinct bone-marrow-failure syndrome due to mutations in ERCC6L2, a gene implicated in DNA repair and mitochondrial function.
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Affiliation(s)
- Hemanth Tummala
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Michael Kirwan
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Amanda J Walne
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Upal Hossain
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK; Barts Health NHS Trust, London E1 1BB, UK
| | - Nicholas Jackson
- Department of Haematology, University Hospital, Coventry CV2 2DX, UK
| | - Corinne Pondarre
- Institute of Pediatric Hematology and Oncology, Lyon I University, Lyon 69008, France
| | - Vincent Plagnol
- University College London Genetics Institute, London WC1E 6BT, UK
| | - Tom Vulliamy
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK.
| | - Inderjeet Dokal
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK; Barts Health NHS Trust, London E1 1BB, UK
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21
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Pereboeva L, Westin E, Patel T, Flaniken I, Lamb L, Klingelhutz A, Goldman F. DNA damage responses and oxidative stress in dyskeratosis congenita. PLoS One 2013; 8:e76473. [PMID: 24124565 PMCID: PMC3790691 DOI: 10.1371/journal.pone.0076473] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/27/2013] [Indexed: 12/23/2022] Open
Abstract
Dyskeratosis congenita (DC) is an inherited multisystem disorder of premature aging, cancer predisposition, and bone marrow failure caused by selective exhaustion of highly proliferative cell pools. DC patients also have a poor tolerance to chemo/radiotherapy and bone marrow transplantation. Although critically shortened telomeres and defective telomere maintenance contribute to DC pathology, other mechanisms likely exist. We investigate the link between telomere dysfunction and oxidative and DNA damage response pathways and assess the effects of antioxidants. In vitro studies employed T lymphocytes from DC subjects with a hTERC mutation and age-matched controls. Cells were treated with cytotoxic agents, including Paclitaxel, Etoposide, or ionizing radiation. Apoptosis and reactive oxygen species (ROS) were assessed by flow cytometry, and Western blotting was used to measure expression of DNA damage response (DDR) proteins, including total p53, p53S15, and p21(WAF). N-acetyl-cysteine (NAC), an antioxidant, was used to modulate cell growth and ROS. In stimulated culture, DC lymphocytes displayed a stressed phenotype, characterized by elevated levels of ROS, DDR and apoptotic markers as well as a proliferative defect that was more pronounced after exposure to cytotoxic agents. NAC partially ameliorated the growth disadvantage of DC cells and decreased radiation-induced apoptosis and oxidative stress. These findings suggest that oxidative stress may play a role in the pathogenesis of DC and that pharmacologic intervention to correct this pro-oxidant imbalance may prove useful in the clinical setting, potentially alleviating untoward toxicities associated with current cytotoxic treatments.
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Affiliation(s)
- Larisa Pereboeva
- Department of Medicine, Division of Hematology Oncology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Erik Westin
- Department of Pediatrics, Division of Hematology Oncology, Children's Hospital of Alabama, Birmingham, Alabama, United States of America
| | - Toral Patel
- Department of Pediatrics, Division of Hematology Oncology, Children's Hospital of Alabama, Birmingham, Alabama, United States of America
| | - Ian Flaniken
- Department of Pediatrics, Division of Hematology Oncology, Children's Hospital of Alabama, Birmingham, Alabama, United States of America
| | - Lawrence Lamb
- Department of Medicine, Division of Hematology Oncology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Aloysius Klingelhutz
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Frederick Goldman
- Department of Pediatrics, Division of Hematology Oncology, Children's Hospital of Alabama, Birmingham, Alabama, United States of America
- * E-mail:
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22
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Winkler T, Hong SG, Decker JE, Morgan MJ, Wu C, Hughes WM, Yang Y, Wangsa D, Padilla-Nash HM, Ried T, Young NS, Dunbar CE, Calado RT. Defective telomere elongation and hematopoiesis from telomerase-mutant aplastic anemia iPSCs. J Clin Invest 2013; 123:1952-63. [PMID: 23585473 DOI: 10.1172/jci67146] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 02/14/2013] [Indexed: 01/04/2023] Open
Abstract
Critically short telomeres activate p53-mediated apoptosis, resulting in organ failure and leading to malignant transformation. Mutations in genes responsible for telomere maintenance are linked to a number of human diseases. We derived induced pluripotent stem cells (iPSCs) from 4 patients with aplastic anemia or hypocellular bone marrow carrying heterozygous mutations in the telomerase reverse transcriptase (TERT) or the telomerase RNA component (TERC) telomerase genes. Both mutant and control iPSCs upregulated TERT and TERC expression compared with parental fibroblasts, but mutant iPSCs elongated telomeres at a lower rate compared with healthy iPSCs, and the deficit correlated with the mutations' impact on telomerase activity. There was no evidence for alternative lengthening of telomere (ALT) pathway activation. Elongation varied among iPSC clones derived from the same patient and among clones from siblings harboring identical mutations. Clonal heterogeneity was linked to genetic and environmental factors, but was not influenced by residual expression of reprogramming transgenes. Hypoxia increased telomere extension in both mutant and normal iPSCs. Additionally, telomerase-mutant iPSCs showed defective hematopoietic differentiation in vitro, mirroring the clinical phenotype observed in patients and demonstrating that human telomere diseases can be modeled utilizing iPSCs. Our data support the necessity of studying multiple clones when using iPSCs to model disease.
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Affiliation(s)
- Thomas Winkler
- Hematology Branch, National Heart Lung and Blood Institute (NHLBI), NIH, Bethesda, Maryland 0892-1202, USA
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23
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Le Guen T, Jullien L, Touzot F, Schertzer M, Gaillard L, Perderiset M, Carpentier W, Nitschke P, Picard C, Couillault G, Soulier J, Fischer A, Callebaut I, Jabado N, Londono-Vallejo A, de Villartay JP, Revy P. Human RTEL1 deficiency causes Hoyeraal-Hreidarsson syndrome with short telomeres and genome instability. Hum Mol Genet 2013; 22:3239-49. [PMID: 23591994 DOI: 10.1093/hmg/ddt178] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hoyeraal-Hreidarsson syndrome (HHS), a severe variant of dyskeratosis congenita (DC), is characterized by early onset bone marrow failure, immunodeficiency and developmental defects. Several factors involved in telomere length maintenance and/or protection are defective in HHS/DC, underlining the relationship between telomere dysfunction and these diseases. By combining whole-genome linkage analysis and exome sequencing, we identified compound heterozygous RTEL1 (regulator of telomere elongation helicase 1) mutations in three patients with HHS from two unrelated families. RTEL1 is a DNA helicase that participates in DNA replication, DNA repair and telomere integrity. We show that, in addition to short telomeres, RTEL1-deficient cells from patients exhibit hallmarks of genome instability, including spontaneous DNA damage, anaphase bridges and telomeric aberrations. Collectively, these results identify RTEL1 as a novel HHS-causing gene and highlight its role as a genomic caretaker in humans.
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24
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Hartwig FP, Collares T. Telomere dysfunction and tumor suppression responses in dyskeratosis congenita: balancing cancer and tissue renewal impairment. Ageing Res Rev 2013; 12:642-52. [PMID: 23541441 DOI: 10.1016/j.arr.2013.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/13/2013] [Accepted: 03/18/2013] [Indexed: 01/06/2023]
Abstract
Dyskeratosis congenita (DC) encompasses a large spectrum of diseases and clinical manifestations generally related to premature aging, including bone marrow failure and cancer predisposition. The major risk factor for DC is to carry germline telomere-related mutations - in telomerase or telomere shelterin genes - which results in premature telomere dysfunction, thus increasing the risk of premature aging impairments. Despite the advances that have been accomplished in DC research, the molecular aspects underlying the phenotypic variability of the disease remain poorly understood. Here different aspects of telomere biology, concerning adult stem cells senescence, tumor suppression and cancer are considered in the context of DC, resulting in two translational models: late onset of DC symptoms in telomere-related mutations carriers is a potential indicator of increased cancer risk and differences in tumor suppression capacities among the genetic subgroups are (at least partial) causes of different clinical manifestations of the disease. The limitations of both models are presented, and further experiments for their validation, as well as clinical implications, are discussed.
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25
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Valdiglesias V, Giunta S, Fenech M, Neri M, Bonassi S. γH2AX as a marker of DNA double strand breaks and genomic instability in human population studies. Mutat Res 2013; 753:24-40. [PMID: 23416207 DOI: 10.1016/j.mrrev.2013.02.001] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 01/30/2013] [Accepted: 02/04/2013] [Indexed: 10/27/2022]
Abstract
DNA double strand breaks (DSB) are the gravest form of DNA damage in eukaryotic cells. Failure to detect DSB and activate appropriate DNA damage responses can cause genomic instability, leading to tumorigenesis and possibly accelerated aging. Phosphorylated histone H2AX (γH2AX) is used as a biomarker of cellular response to DSB and its potential for monitoring DNA damage and repair in human populations has been explored in this review. A systematic search was conducted in PubMed for articles, in English, on human studies reporting γH2AX as a biomarker of either DNA repair or DNA damage. A total of 68 publications were identified. Thirty-four studies (50.0%) evaluated the effect of medical procedures or treatments on γH2AX levels; 20 (29.4%) monitored γH2AX in specific pathological conditions with a case/control or case/case design; 5 studies (7.4%) evaluated the effect of environmental genotoxic exposures, and 9 (13.2%) were descriptive studies on cancer and aging. Peripheral blood lymphocytes (44.6%) or biopsies/tissue specimens (24.3%) were the most commonly used samples. γH2AX was scored by optical microscopy as immunostained foci (78%), or by flow cytometry (16%). Critical features affecting the reliability of the assay, including protocols heterogeneity, specimen, cell cycle, kinetics, study design, and statistical analysis, are hereby discussed. Because of its sensitivity, efficiency and mechanistic relevance, the γH2AX assay has great potential as a DNA damage biomarker; however, the technical and epidemiological heterogeneity highlighted in this review infer a necessity for experimental standardization of the assay.
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Affiliation(s)
- Vanessa Valdiglesias
- Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Roma, Italy
| | - Simona Giunta
- CSIRO Preventative Health Flagship, Adelaide 5000, Australia
| | - Michael Fenech
- CSIRO Preventative Health Flagship, Adelaide 5000, Australia
| | - Monica Neri
- Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Roma, Italy
| | - Stefano Bonassi
- Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Roma, Italy.
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Redon CE, Weyemi U, Parekh PR, Huang D, Burrell AS, Bonner WM. γ-H2AX and other histone post-translational modifications in the clinic. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1819:743-56. [PMID: 22430255 PMCID: PMC3371125 DOI: 10.1016/j.bbagrm.2012.02.021] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/23/2012] [Accepted: 02/28/2012] [Indexed: 12/27/2022]
Abstract
Chromatin is a dynamic complex of DNA and proteins that regulates the flow of information from genome to end product. The efficient recognition and faithful repair of DNA damage, particularly double-strand damage, is essential for genomic stability and cellular homeostasis. Imperfect repair of DNA double-strand breaks (DSBs) can lead to oncogenesis. The efficient repair of DSBs relies in part on the rapid formation of foci of phosphorylated histone H2AX (γ-H2AX) at each break site, and the subsequent recruitment of repair factors. These foci can be visualized with appropriate antibodies, enabling low levels of DSB damage to be measured in samples obtained from patients. Such measurements are proving useful to optimize treatments involving ionizing radiation, to assay in vivo the efficiency of various drugs to induce DNA damage, and to help diagnose patients with a variety of syndromes involving elevated levels of γ-H2AX. We will survey the state of the art of utilizing γ-H2AX in clinical settings. We will also discuss possibilities with other histone post-translational modifications. The ability to measure in vivo the responses of individual patients to particular drugs and/or radiation may help optimize treatments and improve patient care. This article is part of a Special Issue entitled: Chromatin in time and space.
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Affiliation(s)
- Christophe E. Redon
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Urbain Weyemi
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Palak R. Parekh
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Dejun Huang
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
- School of Life Sciences, Lanzhou University, China
| | - Allison S. Burrell
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
- Molecular Medicine Program, Institute of Biomedical Sciences, The George Washington University
| | - William M. Bonner
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 9000 Rockville Pike, Bethesda, MD, 20892, USA
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Touzot F, Gaillard L, Vasquez N, Le Guen T, Bertrand Y, Bourhis J, Leblanc T, Fischer A, Soulier J, de Villartay JP, Revy P. Heterogeneous telomere defects in patients with severe forms of dyskeratosis congenita. J Allergy Clin Immunol 2012; 129:473-82, 482.e1-3. [DOI: 10.1016/j.jaci.2011.09.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/14/2011] [Accepted: 09/22/2011] [Indexed: 10/15/2022]
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