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Ugalde L, Fañanas S, Torres R, Quintana-Bustamante O, Río P. CRISPR/Cas9-mediated gene editing. A promising strategy in hematological disorders. Cytotherapy 2023; 25:277-285. [PMID: 36610813 DOI: 10.1016/j.jcyt.2022.11.014] [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: 12/15/2021] [Revised: 11/09/2022] [Accepted: 11/30/2022] [Indexed: 01/07/2023]
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system has revolutionized the gene editing field, making it possible to interrupt, insert or replace a sequence of interest with high precision in the human genome. Its easy design and wide applicability open up a variety of therapeutic alternatives for the treatment of genetic diseases. Indeed, very promising approaches for the correction of hematological disorders have been developed in the recent years, based on the self-renewal and multipotent differentiation properties of hematopoietic stem and progenitor cells, which make this cell subset the ideal target for gene therapy purposes. This technology has been applied in different congenital blood disorders, such as primary immunodeficiencies, X-linked severe combined immunodeficiency, X-linked chronic granulomatous disease or Wiskott-Aldrich syndrome, and inherited bone marrow failure syndromes, such as Fanconi anemia, congenital amegakaryocytic thrombocytopenia or severe congenital neutropenia. Furthermore, CRISPR/Cas9-based gene editing has been implemented successfully as a novel therapy for cancer immunotherapy, by the development of promising strategies such as the use of oncolytic viruses or adoptive cellular therapy to the chimeric antigen receptor-T-cell therapy. Therefore, considering the variety of genes and mutations affected, we can take advantage of the different DNA repair mechanisms by CRISPR/Cas9 in different manners, from homology-directed repair to non-homologous-end-joining to the latest emerging technologies such as base and prime editing. Although the delivery systems into hematopoietic stem and progenitor cells are still the bottleneck of this technology, some of the advances in genome editing shown in this review have already reached a clinical stage and show very promising preliminary results.
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Affiliation(s)
- Laura Ugalde
- Biomedical Innovation Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Sara Fañanas
- Biomedical Innovation Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Raúl Torres
- Biomedical Innovation Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain; Molecular Cytogenetics Group, Human Cancer Genetics Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid, Spain
| | - Oscar Quintana-Bustamante
- Biomedical Innovation Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Paula Río
- Biomedical Innovation Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain.
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Lassandro G, Palladino V, Faleschini M, Barone A, Boscarol G, Cesaro S, Chiocca E, Farruggia P, Giona F, Gorio C, Maggio A, Marinoni M, Marzollo A, Palumbo G, Russo G, Saracco P, Spinelli M, Verzegnassi F, Morga F, Savoia A, Giordano P. "CHildren with Inherited Platelet disorders Surveillance" (CHIPS) retrospective and prospective observational cohort study by Italian Association of Pediatric Hematology and Oncology (AIEOP). Front Pediatr 2022; 10:967417. [PMID: 36507135 PMCID: PMC9728612 DOI: 10.3389/fped.2022.967417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 10/18/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Inherited thrombocytopenias (ITs) are rare congenital bleeding disorders characterized by different clinical expression and variable prognosis. ITs are poorly known by clinicians and often misdiagnosed with most common forms of thrombocytopenia. MATERIAL AND METHODS "CHildren with Inherited Platelet disorders Surveillance" study (CHIPS) is a retrospective - prospective observational cohort study conducted between January 2003 and January 2022 in 17 centers affiliated to the Italian Association of Pediatric Hematology and Oncology (AIEOP). The primary objective of this study was to collect clinical and laboratory data on Italian pediatric patients with inherited thrombocytopenias. Secondary objectives were to calculate prevalence of ITs in Italian pediatric population and to assess frequency and genotype-phenotype correlation of different types of mutations in our study cohort. RESULTS A total of 139 children, with ITs (82 male - 57 female) were enrolled. ITs prevalence in Italy ranged from 0.7 per 100,000 children during 2010 to 2 per 100,000 children during 2022. The median time between the onset of thrombocytopenia and the diagnosis of ITs was 1 years (range 0 - 18 years). A family history of thrombocytopenia has been reported in 90 patients (65%). Among 139 children with ITs, in 73 (53%) children almost one defective gene has been identified. In 61 patients a pathogenic mutation has been identified. Among them, 2 patients also carry a variant of uncertain significance (VUS), and 4 others harbour 2 VUS variants. VUS variants were identified in further 8 patients (6%), 4 of which carry more than one variant VUS. Three patients (2%) had a likely pathogenic variant while in 1 patient (1%) a variant was identified that was initially given an uncertain significance but was later classified as benign. In addition, in 17 patients the genetic diagnosis is not available, but their family history and clinical/laboratory features strongly suggest the presence of a specific genetic cause. In 49 children (35%) no genetic defect were identified. In ninetyseven patients (70%), thrombocytopenia was not associated with other clinically apparent disorders. However, 42 children (30%) had one or more additional clinical alterations. CONCLUSION Our study provides a descriptive collection of ITs in the pediatric Italian population.
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Affiliation(s)
- Giuseppe Lassandro
- Interdisciplinary Department of Medicine, Pediatric Section, University of Bari "Aldo Moro", Bari, Italy
| | - Valentina Palladino
- Interdisciplinary Department of Medicine, Pediatric Section, University of Bari "Aldo Moro", Bari, Italy
| | - Michela Faleschini
- Department of Medical Genetics, Institute for Maternal and Child Health-IRCCS Burlo Garofolo, Trieste, Italy
| | - Angelica Barone
- Pediatric Hematology Oncology, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria di Parma, Parma, Italy
| | - Gianluca Boscarol
- Department of Pediatrics, Central Teaching Hospital of Bolzano/Bozen, Bolzano, Italy
| | - Simone Cesaro
- Pediatric Hematology Oncology, Department of Mother and Child, Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Elena Chiocca
- Pediatric Hematology Oncology, Department of Pediatric Hematology/Oncology and HSCT, Meyer Children's University Hospital, Florence, Italy
| | - Piero Farruggia
- Pediatric Hematology and Oncology Unit, ARNAS (Azienda di Rilievo Nazionale ad Alta Specializzazione) Ospedale Civico, Palermo, Italy
| | - Fiorina Giona
- Department of Translational and Precision Medicine, Sapienza University of Rome, AOU Policlinico Umberto I, Rome, Italy
| | - Chiara Gorio
- Hematology Oncology Unit, Children's Hospital, ASST Spedali Civili, Brescia, Italy
| | - Angela Maggio
- UOC Oncoematologia Pediatrica-IRCCS Ospedale Casa Sollievo Della Sofferenza, San Giovanni Rotondo, Italy
| | - Maddalena Marinoni
- Pediatric Hematology Oncology, Department of Mother and Child, Azienda Socio Sanitaria Settelaghi, Varese, Italy
| | - Antonio Marzollo
- Pediatric Hematology, Oncology and Stem Cell Transplant Division, Padua University Hospital, Padua, Italy
| | - Giuseppe Palumbo
- Department of Pediatric Hematology and Oncology Cell and Gene Therapy, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.,Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Giovanna Russo
- Pediatric Hematology Oncology, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Paola Saracco
- Pediatric Hematology, Department of Pediatrics, University Hospital Città Della Salute e Della Scienza, Turin, Italy
| | - Marco Spinelli
- Pediatric Hematology Oncology, Department of Pediatrics, MBBM Foundation, Monza, Italy
| | - Federico Verzegnassi
- Department of Medical Genetics, Institute for Maternal and Child Health-IRCCS Burlo Garofolo, Trieste, Italy
| | - Francesca Morga
- Interdisciplinary Department of Medicine, Pediatric Section, University of Bari "Aldo Moro", Bari, Italy
| | - Anna Savoia
- Department of Medical Genetics, Institute for Maternal and Child Health-IRCCS Burlo Garofolo, Trieste, Italy.,Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Paola Giordano
- Interdisciplinary Department of Medicine, Pediatric Section, University of Bari "Aldo Moro", Bari, Italy
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Paul M, Killikulangara Sadanandan A, Abraham L, Madany Pathrose S, Varghese D. An Unusual Case of Severe Persistent Neonatal Thrombocytopenia in an Extremely Low Birth Weight, Extreme Preterm Neonate. Glob Pediatr Health 2021; 8:2333794X211038724. [PMID: 34414253 PMCID: PMC8369956 DOI: 10.1177/2333794x211038724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 07/21/2021] [Indexed: 11/15/2022] Open
Abstract
Neonatal thrombocytopenia is a common hematological problem but refractory thrombocytopenia is very rare in neonates. A systematic and diligent workup will result in arriving at the proper diagnosis and providing accurate management in rare causes of neonatal thrombocytopenia. We report a case of severe refractory thrombocytopenia in an extremely low birth weight (ELBW)/extreme preterm baby who presented with early onset severe thrombocytopenia associated with anemia and required multiple platelet transfusions. After ruling out COVID-19 infection, sepsis and neonatal alloimmune thrombocytopenia (NAIT), the cause for severe refractory thrombocytopenia was diagnosed as Type II congenital amegakaryocytic thrombocytopenia (CAMT) by bone marrow examination and MPL gene mutation studies.
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Hitchcock IS, Hafer M, Sangkhae V, Tucker JA. The thrombopoietin receptor: revisiting the master regulator of platelet production. Platelets 2021; 32:770-778. [PMID: 34097561 PMCID: PMC8292222 DOI: 10.1080/09537104.2021.1925102] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 12/25/2022]
Abstract
Thrombopoietin (TPO) and its receptor, MPL, are the primary regulators of platelet production and critical for hematopoietic stem cell (HSC) maintenance. Since TPO was first cloned in 1994, the physiological and pathological roles of TPO and MPL have been well characterized, culminating in the first MPL agonists being approved for the treatment of chronic immune thrombocytopenia in 2008. Dysregulation of the TPO-MPL signaling axis contributes to the pathogenesis of hematological disorders: decreased expression or function results in severe thrombocytopenia progressing to bone marrow failure, while hyperactivation of MPL signaling, either by mutations in the receptor or associated Janus kinase 2 (JAK2), results in pathological myeloproliferation. Despite its importance, it was only recently that the long-running debate over the mechanism by which TPO binding activates MPL has been resolved. This review will cover key aspects of TPO and MPL structure and function and their importance in receptor activation, discuss how these are altered in hematological disorders and consider how a greater understanding could lead to the development of better-targeted and more efficacious therapies.
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Affiliation(s)
- Ian S. Hitchcock
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | - Maximillian Hafer
- Department of Biology and Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Veena Sangkhae
- Center for Iron Disorders, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Julie A. Tucker
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
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5
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Turro E, Astle WJ, Megy K, Gräf S, Greene D, Shamardina O, Allen HL, Sanchis-Juan A, Frontini M, Thys C, Stephens J, Mapeta R, Burren OS, Downes K, Haimel M, Tuna S, Deevi SVV, Aitman TJ, Bennett DL, Calleja P, Carss K, Caulfield MJ, Chinnery PF, Dixon PH, Gale DP, James R, Koziell A, Laffan MA, Levine AP, Maher ER, Markus HS, Morales J, Morrell NW, Mumford AD, Ormondroyd E, Rankin S, Rendon A, Richardson S, Roberts I, Roy NBA, Saleem MA, Smith KGC, Stark H, Tan RYY, Themistocleous AC, Thrasher AJ, Watkins H, Webster AR, Wilkins MR, Williamson C, Whitworth J, Humphray S, Bentley DR, Kingston N, Walker N, Bradley JR, Ashford S, Penkett CJ, Freson K, Stirrups KE, Raymond FL, Ouwehand WH. Whole-genome sequencing of patients with rare diseases in a national health system. Nature 2020; 583:96-102. [PMID: 32581362 PMCID: PMC7610553 DOI: 10.1038/s41586-020-2434-2] [Citation(s) in RCA: 277] [Impact Index Per Article: 69.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 05/05/2020] [Indexed: 02/02/2023]
Abstract
Most patients with rare diseases do not receive a molecular diagnosis and the aetiological variants and causative genes for more than half such disorders remain to be discovered1. Here we used whole-genome sequencing (WGS) in a national health system to streamline diagnosis and to discover unknown aetiological variants in the coding and non-coding regions of the genome. We generated WGS data for 13,037 participants, of whom 9,802 had a rare disease, and provided a genetic diagnosis to 1,138 of the 7,065 extensively phenotyped participants. We identified 95 Mendelian associations between genes and rare diseases, of which 11 have been discovered since 2015 and at least 79 are confirmed to be aetiological. By generating WGS data of UK Biobank participants2, we found that rare alleles can explain the presence of some individuals in the tails of a quantitative trait for red blood cells. Finally, we identified four novel non-coding variants that cause disease through the disruption of transcription of ARPC1B, GATA1, LRBA and MPL. Our study demonstrates a synergy by using WGS for diagnosis and aetiological discovery in routine healthcare.
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Affiliation(s)
- Ernest Turro
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK.
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK.
| | - William J Astle
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
| | - Karyn Megy
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Stefan Gräf
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Daniel Greene
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Olga Shamardina
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Hana Lango Allen
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Alba Sanchis-Juan
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Mattia Frontini
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
- British Heart Foundation Cambridge Centre of Excellence, University of Cambridge, Cambridge, UK
| | - Chantal Thys
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Leuven, Belgium
| | - Jonathan Stephens
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Rutendo Mapeta
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Oliver S Burren
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Kate Downes
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Matthias Haimel
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Salih Tuna
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Sri V V Deevi
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Timothy J Aitman
- MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, UK
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - David L Bennett
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
| | - Paul Calleja
- High Performance Computing Service, University of Cambridge, Cambridge, UK
| | - Keren Carss
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Mark J Caulfield
- Genomics England Ltd, London, UK
- William Harvey Research Institute, NIHR Biomedical Research Centre at Barts, Queen Mary University of London, London, UK
| | - Patrick F Chinnery
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, UK
| | - Peter H Dixon
- Women and Children's Health, School of Life Course Sciences, King's College London, London, UK
| | - Daniel P Gale
- Department of Renal Medicine, University College London, London, UK
- Rare Renal Disease Registry, UK Renal Registry, Bristol, UK
| | - Roger James
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Ania Koziell
- King's College London, London, UK
- Department of Paediatric Nephrology, Evelina London Children's Hospital, Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - Michael A Laffan
- Department of Haematology, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK
- Centre for Haematology, Imperial College London, London, UK
| | - Adam P Levine
- Department of Renal Medicine, University College London, London, UK
| | - Eamonn R Maher
- Department of Medical Genetics, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK
- Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Hugh S Markus
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Bristol, UK
| | - Joannella Morales
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
| | - Nicholas W Morrell
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Andrew D Mumford
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
- University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Elizabeth Ormondroyd
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
- Department of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Stuart Rankin
- High Performance Computing Service, University of Cambridge, Cambridge, UK
| | - Augusto Rendon
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Genomics England Ltd, London, UK
| | - Sylvia Richardson
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Irene Roberts
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Department of Paediatrics, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Noemi B A Roy
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Moin A Saleem
- Bristol Renal and Children's Renal Unit, Bristol Medical School, University of Bristol, Bristol, UK
- Bristol Royal Hospital for Children, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Kenneth G C Smith
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Hannah Stark
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Rhea Y Y Tan
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Bristol, UK
| | - Andreas C Themistocleous
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | | | - Hugh Watkins
- Department of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Andrew R Webster
- Moorfields Eye Hospital NHS Trust, London, UK
- UCL Institute of Opthalmology, University College London, London, UK
| | | | - Catherine Williamson
- Women and Children's Health, School of Life Course Sciences, King's College London, London, UK
- Institute of Reproductive and Developmental Biology, Department of Surgery and Cancer, Faculty of Medicine, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - James Whitworth
- Department of Medical Genetics, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK
- Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
| | | | | | - Nathalie Kingston
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Neil Walker
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - John R Bradley
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK
- Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Department of Renal Medicine, Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Sofie Ashford
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Christopher J Penkett
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Kathleen Freson
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Leuven, Belgium
| | - Kathleen E Stirrups
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - F Lucy Raymond
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK.
- Department of Medical Genetics, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
| | - Willem H Ouwehand
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK.
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK.
- British Heart Foundation Cambridge Centre of Excellence, University of Cambridge, Cambridge, UK.
- Wellcome Sanger Institute, Cambridge, UK.
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6
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Saes JL, Simons A, de Munnik SA, Nijziel MR, Blijlevens NMA, Jongmans MC, van der Reijden BA, Smit Y, Brons PP, van Heerde WL, Schols SEM. Whole exome sequencing in the diagnostic workup of patients with a bleeding diathesis. Haemophilia 2018; 25:127-135. [PMID: 30431218 DOI: 10.1111/hae.13638] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Bleeding assessment tools and laboratory phenotyping often remain inconclusive in patients with a haemorrhagic diathesis. AIM To describe the phenotype and genetic profile of patients with a bleeding tendency. METHODS Whole exome sequencing (WES) was incorporated in the routine diagnostic pathway of patients with thrombocytopenia (n = 17), platelet function disorders (n = 19) and an unexplained bleeding tendency (n = 51). The analysis of a panel of 126 OMIM (Online Mendelian Inheritance in Man) genes involved in thrombosis and haemostasis was conducted, and if negative, further exome-wide analysis was performed if informed consent given. RESULTS Eighteen variants were detected in 15 patients from a total of 87 patients (17%). Causative variants were observed in MYH9 (two cases), SLFN14, P2RY12 and GP9. In addition, one case was considered solved due to combined carriership of F7 and F13A1 variants and one with combined carriership of F2, F8 and VWF, all variants related to secondary haemostasis protein aberrations. Two variants of uncertain significance (VUS) were found in two primary haemostasis genes: GFI1B and VWF. Eight patients were carriers of autosomal recessive disorders. Exome-wide analysis was performed in 54 cases and identified three variants in candidate genes. CONCLUSION Based on our findings, we conclude that performing WES at the end of the diagnostic trajectory can be of additive value to explain the complete bleeding phenotype in patients without a definite diagnosis after conventional laboratory tests. Discovery of combinations of (novel) genes that predispose to bleeding will increase the diagnostic yield in patients with an unexplained bleeding diathesis.
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Affiliation(s)
- Joline L Saes
- Department of Hematology, Radboud University Medical Center, Nijmegen, The Netherlands.,Hemophilia Treatment Center, Nijmegen-Eindhoven-Maastricht, Nijmegen, The Netherlands
| | - Annet Simons
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sonja A de Munnik
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marten R Nijziel
- Department of Hematology, Catharina Hospital, Eindhoven, The Netherlands
| | - Nicole M A Blijlevens
- Department of Hematology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marjolijn C Jongmans
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands.,Princess Maxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Bert A van der Reijden
- Department of Laboratory Medicine, Laboratory of Haematology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Yolba Smit
- Department of Hematology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Paul P Brons
- Hemophilia Treatment Center, Nijmegen-Eindhoven-Maastricht, Nijmegen, The Netherlands.,Department of Pediatric Hemato-Oncology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Waander L van Heerde
- Hemophilia Treatment Center, Nijmegen-Eindhoven-Maastricht, Nijmegen, The Netherlands
| | - Saskia E M Schols
- Department of Hematology, Radboud University Medical Center, Nijmegen, The Netherlands.,Hemophilia Treatment Center, Nijmegen-Eindhoven-Maastricht, Nijmegen, The Netherlands
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7
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Gene editing rescue of a novel MPL mutant associated with congenital amegakaryocytic thrombocytopenia. Blood Adv 2017; 1:1815-1826. [PMID: 29296828 DOI: 10.1182/bloodadvances.2016002915] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 08/10/2017] [Indexed: 12/19/2022] Open
Abstract
Thrombopoietin (Tpo) and its receptor (Mpl) are the principal regulators of early and late thrombopoiesis and hematopoietic stem cell maintenance. Mutations in MPL can drastically impair its function and be a contributing factor in multiple hematologic malignancies, including congenital amegakaryocytic thrombocytopenia (CAMT). CAMT is characterized by severe thrombocytopenia at birth, which progresses to bone marrow failure and pancytopenia. Here we report unique familial cases of CAMT that presented with a previously unreported MPL mutation: T814C (W272R) in the background of the activating MPL G117T (K39N or Baltimore) mutation. Confocal microscopy, proliferation and surface biotinylation assays, co-immunoprecipitation, and western blotting analysis were used to elucidate the function and trafficking of Mpl mutants. Results showed that Mpl protein bearing the W272R mutation, alone or together with the K39N mutation, lacks detectable surface expression while being strongly colocalized with the endoplasmic reticulum (ER) marker calreticulin. Both WT and K39N-mutated Mpl were found to be signaling competent, but single or double mutants bearing W272R were unresponsive to Tpo. Function of the deficient Mpl receptor could be rescued by using 2 separate approaches: (1) GRASP55 overexpression, which partially restored Tpo-induced signaling of mutant Mpl by activating an autophagy-dependent secretory pathway and thus forcing ER-trapped immature receptors to traffic to the cell surface; and (2) CRISPR-Cas9 gene editing used to repair MPL T814C mutation in transfected cell lines and primary umbilical cord blood-derived CD34+ cells. We demonstrate proof of principle for rescue of mutant Mpl function by using gene editing of primary hematopoietic stem cells, which indicates direct therapeutic applications for CAMT patients.
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8
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Bellanné-Chantelot C, Mosca M, Marty C, Favier R, Vainchenker W, Plo I. Identification of MPL R102P Mutation in Hereditary Thrombocytosis. Front Endocrinol (Lausanne) 2017; 8:235. [PMID: 28979237 PMCID: PMC5611484 DOI: 10.3389/fendo.2017.00235] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 08/28/2017] [Indexed: 01/11/2023] Open
Abstract
The molecular basis of hereditary thrombocytosis is germline mutations affecting the thrombopoietin (TPO)/TPO receptor (MPL)/JAK2 signaling axis. Here, we report one family presenting two cases with a mild thrombocytosis. By sequencing JAK2 and MPL coding exons, we identified a germline MPL R102P heterozygous mutation in the proband and his daughter. Concomitantly, we detected high TPO levels in the serum of these two patients. The mutation was not found in three other unaffected cases from the family except in another proband's daughter who did not present thrombocytosis but had a high TPO level. The MPL R102P mutation was first described in congenital amegakaryocytic thrombocytopenia in a homozygous state with a loss-of-function activity. It was previously shown that MPL R102P was blocked in the endoplasmic reticulum without being able to translocate to the plasma membrane. Thus, this case report identifies for the first time that MPL R102P mutation can differently impact megakaryopoiesis: thrombocytosis or thrombocytopenia depending on the presence of the heterozygous or homozygous state, respectively. The paradoxical effect associated with heterozygous MPL R102P may be due to subnormal cell-surface expression of wild-type MPL in platelets inducing a defective TPO clearance. As a consequence, increased TPO levels may activate megakaryocyte progenitors that express a lower, but still sufficient level of MPL for the induction of proliferation.
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Affiliation(s)
- Christine Bellanné-Chantelot
- INSERM UMR1170, Gustave Roussy, Villejuif, France
- Department of Genetics, Assistance Publique-Hôpitaux de Paris (AP-HP) Hôpitaux Universitaires Pitié Salpêtrière—Charles Foix, UPMC Univ Paris 06, Paris, France
| | - Matthieu Mosca
- INSERM UMR1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Gustave Roussy, UMR1170, Villejuif, France
| | - Caroline Marty
- INSERM UMR1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Gustave Roussy, UMR1170, Villejuif, France
| | - Rémi Favier
- INSERM UMR1170, Gustave Roussy, Villejuif, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Service d’Hématologie biologique, Centre de Référence des Pathologies Plaquettaires (CRPP), Hôpital Armand Trousseau, Paris, France
| | - William Vainchenker
- INSERM UMR1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Gustave Roussy, UMR1170, Villejuif, France
| | - Isabelle Plo
- INSERM UMR1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Gustave Roussy, UMR1170, Villejuif, France
- *Correspondence: Isabelle Plo,
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9
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Varghese LN, Defour JP, Pecquet C, Constantinescu SN. The Thrombopoietin Receptor: Structural Basis of Traffic and Activation by Ligand, Mutations, Agonists, and Mutated Calreticulin. Front Endocrinol (Lausanne) 2017; 8:59. [PMID: 28408900 PMCID: PMC5374145 DOI: 10.3389/fendo.2017.00059] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/17/2017] [Indexed: 12/13/2022] Open
Abstract
A well-functioning hematopoietic system requires a certain robustness and flexibility to maintain appropriate quantities of functional mature blood cells, such as red blood cells and platelets. This review focuses on the cytokine receptor that plays a significant role in thrombopoiesis: the receptor for thrombopoietin (TPO-R; also known as MPL). Here, we survey the work to date to understand how this receptor functions at a molecular level throughout its lifecycle, from traffic to the cell surface, dimerization and binding cognate cytokine via its extracellular domain, through to its subsequent activation of associated Janus kinases and initiation of downstream signaling pathways, as well as the regulation of these processes. Atomic level resolution structures of TPO-R have remained elusive. The identification of disease-causing mutations in the receptor has, however, offered some insight into structure and function relationships, as has artificial means of receptor activation, through TPO mimetics, transmembrane-targeting receptor agonists, and engineering in dimerization domains. More recently, a novel activation mechanism was identified whereby mutated forms of calreticulin form complexes with TPO-R via its extracellular N-glycosylated domain. Such complexes traffic pathologically in the cell and persistently activate JAK2, downstream signal transducers and activators of transcription (STATs), and other pathways. This pathologic TPO-R activation is associated with a large fraction of human myeloproliferative neoplasms.
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Affiliation(s)
- Leila N. Varghese
- Ludwig Institute for Cancer Research, Brussels Branch, Brussels, Belgium
- SIGN Pole, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Jean-Philippe Defour
- Ludwig Institute for Cancer Research, Brussels Branch, Brussels, Belgium
- SIGN Pole, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
- Department of Clinical Biology, Cliniques universitaires St Luc, Université catholique de Louvain, Brussels, Belgium
| | - Christian Pecquet
- Ludwig Institute for Cancer Research, Brussels Branch, Brussels, Belgium
- SIGN Pole, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Stefan N. Constantinescu
- Ludwig Institute for Cancer Research, Brussels Branch, Brussels, Belgium
- SIGN Pole, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
- *Correspondence: Stefan N. Constantinescu,
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10
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Plo I, Bellanné-Chantelot C, Mosca M, Mazzi S, Marty C, Vainchenker W. Genetic Alterations of the Thrombopoietin/MPL/JAK2 Axis Impacting Megakaryopoiesis. Front Endocrinol (Lausanne) 2017; 8:234. [PMID: 28955303 PMCID: PMC5600916 DOI: 10.3389/fendo.2017.00234] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/28/2017] [Indexed: 12/31/2022] Open
Abstract
Megakaryopoiesis is an original and complex cell process which leads to the formation of platelets. The homeostatic production of platelets is mainly regulated and controlled by thrombopoietin (TPO) and the TPO receptor (MPL)/JAK2 axis. Therefore, any hereditary or acquired abnormality affecting this signaling axis can result in thrombocytosis or thrombocytopenia. Thrombocytosis can be due to genetic alterations that affect either the intrinsic MPL signaling through gain-of-function (GOF) activity (MPL, JAK2, CALR) and loss-of-function (LOF) activity of negative regulators (CBL, LNK) or the extrinsic MPL signaling by THPO GOF mutations leading to increased TPO synthesis. Alternatively, thrombocytosis may paradoxically result from mutations of MPL leading to an abnormal MPL trafficking, inducing increased TPO levels by alteration of its clearance. In contrast, thrombocytopenia can also result from LOF THPO or MPL mutations, which cause a complete defect in MPL trafficking to the cell membrane, impaired MPL signaling or stability, defects in the TPO/MPL interaction, or an absence of TPO production.
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Affiliation(s)
- Isabelle Plo
- INSERM UMR 1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Gustave Roussy, UMR1170, Villejuif, France
| | - Christine Bellanné-Chantelot
- INSERM UMR 1170, Gustave Roussy, Villejuif, France
- Department of Genetics, AP-HP Hôpitaux Universitaires Pitié Salpêtrière - Charles Foix, UPMC Univ Paris 06, Paris, France
| | - Matthieu Mosca
- INSERM UMR 1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Gustave Roussy, UMR1170, Villejuif, France
| | - Stefania Mazzi
- INSERM UMR 1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Université Paris-Diderot, Paris, France
| | - Caroline Marty
- INSERM UMR 1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Gustave Roussy, UMR1170, Villejuif, France
| | - William Vainchenker
- INSERM UMR 1170, Gustave Roussy, Villejuif, France
- Université Paris-Saclay, UMR1170, Gustave Roussy, Villejuif, France
- Gustave Roussy, UMR1170, Villejuif, France
- *Correspondence: William Vainchenker,
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11
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Woods G, Bajwa RPS, Rose MJ. Reduced intensity transplantation for congenital amegakaryocytic thrombocytopenia: report of a case and review of the literature. Pediatr Transplant 2014; 18:E31-4. [PMID: 24119002 DOI: 10.1111/petr.12175] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/29/2013] [Indexed: 11/28/2022]
Abstract
CAMT is a bone marrow failure syndrome that usually presents with isolated thrombocytopenia soon after birth. HSCT is curative, and MAC is associated with increased transplant-related morbidity and mortality, especially in the unrelated setting. We used a RIC regimen with alemtuzumab, fludarabine, and melphalan in a seven-month-old patient with CAMT who underwent a MUD HSCT. The transplant was well tolerated with few complications. Neutrophil and platelet engraftment occurred on day +12 and +29, respectively, and she had 100% donor chimerisms on days +19.
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Affiliation(s)
- Gary Woods
- Department of Hematology/Oncology/BMT, Nationwide Children's Hospital, Ohio State University, Columbus, OH, USA
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12
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Varghese LN, Zhang JG, Young SN, Willson TA, Alexander WS, Nicola NA, Babon JJ, Murphy JM. Functional characterization of c-Mpl ectodomain mutations that underlie congenital amegakaryocytic thrombocytopenia. Growth Factors 2014; 32:18-26. [PMID: 24438083 DOI: 10.3109/08977194.2013.874347] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Activation of the cell surface receptor, c-Mpl, by the cytokine, thrombopoietin (TPO), underpins megakaryocyte and platelet production in mammals. In humans, mutations in c-Mpl have been identified as the molecular basis of Congenital Amegakaryocytic Thrombocytopenia (CAMT). Here, we show that CAMT-associated mutations in c-Mpl principally lead to defective receptor presentation on the cell surface. In contrast, one CAMT mutant c-Mpl, F104S, was expressed on the cell surface, but showed defective TPO binding and receptor activation. Using mutational analyses, we examined which residues adjacent to F104 within the membrane-distal cytokine receptor homology module (CRM) of c-Mpl comprise the TPO-binding epitope, revealing residues within the predicted Domain 1 E-F and A-B loops and Domain 2 F'-G' loop as key TPO-binding determinants. These studies underscore the importance of the c-Mpl membrane-distal CRM to TPO-binding and suggest that mutations within this CRM that perturb TPO binding could give rise to CAMT.
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Affiliation(s)
- Leila N Varghese
- The Walter and Eliza Hall Institute of Medical Research , Parkville, Victoria , Australia and
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13
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Pecci A. Pathogenesis and management of inherited thrombocytopenias: rationale for the use of thrombopoietin-receptor agonists. Int J Hematol 2013; 98:34-47. [PMID: 23636669 DOI: 10.1007/s12185-013-1351-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 12/30/2022]
Abstract
Knowledge in the field of inherited thrombocytopenias (ITs) has considerably improved over the recent years. In the last 5 years, nine new genes whose mutations are responsible for thrombocytopenia have been identified, and this also led to the recognition of several novel nosographic entities, such as thrombocytopenias deriving from mutations in CYCS, TUBB1, FLNA, ITGA2B/ITGB3, ANKRD26 and ACTN1. The identification of novel molecular alterations causing thrombocytopenia together with improvement of methodologies to study megakaryopoiesis led to considerable advances in understanding pathophysiology of ITs, thus providing the background for proposing new treatments. Thrombopoietin-receptor agonists (TPO-RAs) represent an appealing therapeutic hypothesis for ITs and have been tested in a limited number of patients. In this review, we provide an updated description of pathogenetic mechanisms of thrombocytopenia in the different forms of ITs and recapitulate the current management of these disorders. Moreover, we report the available clinical and preclinical data about the role of TPO-RAs in ITs and discuss the rationale for the use of these molecules in view of pathogenesis of the different forms of thrombocytopenia of genetic origin.
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Affiliation(s)
- Alessandro Pecci
- Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation, University of Pavia, Piazzale Golgi, 27100 Pavia, Italy.
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14
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He X, Chen Z, Jiang Y, Qiu X, Zhao X. Different mutations of the human c-mpl gene indicate distinct haematopoietic diseases. J Hematol Oncol 2013; 6:11. [PMID: 23351976 PMCID: PMC3563459 DOI: 10.1186/1756-8722-6-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 01/22/2013] [Indexed: 11/10/2022] Open
Abstract
The human c-mpl gene (MPL) plays an important role in the development of megakaryocytes and platelets as well as the self-renewal of haematopoietic stem cells. However, numerous MPL mutations have been identified in haematopoietic diseases. These mutations alter the normal regulatory mechanisms and lead to autonomous activation or signalling deficiencies. In this review, we summarise 59 different MPL mutations and classify these mutations into four different groups according to the associated diseases and mutation rates. Using this classification, we clearly distinguish four diverse types of MPL mutations and obtain a deep understand of their clinical significance. This will prove to be useful for both disease diagnosis and the design of individual therapy regimens based on the type of MPL mutations.
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Affiliation(s)
- Xin He
- Department of Hematology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
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15
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Geddis AE. Congenital amegakaryocytic thrombocytopenia. Pediatr Blood Cancer 2011; 57:199-203. [PMID: 21337678 DOI: 10.1002/pbc.22927] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 11/29/2010] [Indexed: 12/29/2022]
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is clinically characterized by thrombocytopenia presenting at birth in a child without congenital or skeletal malformations, reduced or absent bone marrow megakaryocytes, and eventual progression to bone marrow failure. Molecular studies in most cases confirm homozygous or compound heterozygous mutations in the thrombopoietin receptor c-Mpl. In addition to the clinical importance of recognizing this disorder, characterization of mutations identified in patients with CAMT has led to insights into thrombopoietin receptor structure and function. This review will summarize the diagnosis, pathophysiology, and management of CAMT.
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Affiliation(s)
- Amy E Geddis
- Pediatric Hematology-Oncology, University of California San Diego, Rady Children's Hospital San Diego, San Diego, California 92123, USA.
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16
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Albu RI, Constantinescu SN. Extracellular domain N-glycosylation controls human thrombopoietin receptor cell surface levels. Front Endocrinol (Lausanne) 2011; 2:71. [PMID: 22649382 PMCID: PMC3355985 DOI: 10.3389/fendo.2011.00071] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 10/21/2011] [Indexed: 01/13/2023] Open
Abstract
The thrombopoietin receptor (TpoR) is a type I transmembrane protein that mediates the signaling functions of thrombopoietin (Tpo) in regulating megakaryocyte differentiation, platelet formation, and hematopoietic stem cell renewal. We probed the role of each of the four extracellular domain putative N-glycosylation sites for cell surface localization and function of the receptor. Single N-glycosylation mutants at any of the four sites were able to acquire the mature N-glycosylated pattern, but exhibited a decreased Tpo-dependent JAK2-STAT response in stably transduced Ba/F3 or Ba/F3-JAK2 cell lines. The ability of JAK2 to promote cell surface localization and stability of TpoR required the first N-glycosylation site (Asn117). In contrast, the third N-glycosylation site (Asn298) decreased receptor maturation and stability. TpoR mutants lacking three N-glycosylation sites were defective in maturation, but N-glycosylation on the single remaining site could be detected by sensitivity to PNGaseF. The TpoR mutant defective in all four N-glycosylation sites was severely impaired in plasma membrane localization and was degraded by the proteasome. N-glycosylation receptor mutants are not misfolded as, once localized on the cell surface in overexpression conditions, they can bind and respond to Tpo. Our data indicate that extracellular domain N-glycosylation sites regulate in a combinatorial manner cell surface localization of TpoR. We discuss how mutations around TpoR N-glycosylation sites might contribute to inefficient receptor traffic and disease.
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Affiliation(s)
- Roxana I. Albu
- Ludwig Institute for Cancer ResearchBrussels, Belgium
- de Duve Institute, Université catholique de LouvainBrussels, Belgium
| | - Stefan N. Constantinescu
- Ludwig Institute for Cancer ResearchBrussels, Belgium
- de Duve Institute, Université catholique de LouvainBrussels, Belgium
- *Correspondence: Stefan N. Constantinescu, Ludwig Institute for Cancer Research, de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 74, UCL 75-4, Brussels B-1200, Belgium. e-mail:
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17
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Geddis AE. Congenital amegakaryocytic thrombocytopenia and thrombocytopenia with absent radii. Hematol Oncol Clin North Am 2009; 23:321-31. [PMID: 19327586 DOI: 10.1016/j.hoc.2009.01.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Thrombocytopenia is a relatively common clinical problem in hospitalized neonates, and it is critical to distinguish infants who have rare congenital thrombocytopenias from those who have acquired disorders. Two well-described inherited thrombocytopenia syndromes that present in the newborn period are congenital amegakaryocytic thrombocytopenia (CAMT) and thrombocytopenia with absent radii (TAR). Although both are characterized by severe (< 50,000/microL) thrombocytopenia at birth, the molecular mechanisms underlying these disorders and their clinical presentations and courses are distinct. CAMT is an autosomal recessive disorder caused by mutations in the thrombopoietin (TPO) receptor c-Mpl. TAR is a syndrome of variable inheritance and unclear genetic etiology consisting of thrombocytopenia in association with bilateral absent radii and frequently additional congenital abnormalities. This article summarizes the current understanding of the pathophysiology and clinical course of CAMT and TAR.
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Affiliation(s)
- Amy E Geddis
- Department of Pediatrics, University of California San Diego, Rady Children's Hospital, 9500 Gilman Dr., Mailcode 0671, San Diego, CA 92093, USA.
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18
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Ballmaier M, Germeshausen M. Advances in the understanding of congenital amegakaryocytic thrombocytopenia. Br J Haematol 2009; 146:3-16. [PMID: 19388932 DOI: 10.1111/j.1365-2141.2009.07706.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Congenital amegakaryocytic thrombocytopenia (MIM #604498) is an extremely rare inherited bone marrow failure syndrome, usually presenting as a severe thrombocytopenia at birth due to ineffective megakaryocytopoiesis and no characteristic physical anomalies. Usually the isolated thrombocytopenia progresses to pancytopenia during the first years of life. The only curative therapy to date is haematopoietic stem cell transplantation. Most of the cases of congenital amegakaryocytic thrombocytopenia are caused by defective expression or function of the thrombopoietin receptor due to homozygous or compound heterozygous mutations in the gene MPL. The essential roles of thrombopoietin as a lineage specific regulator of platelet production and as a regulator of haematopoietic stem cell function are reflected in the haematological defects seen in affected individuals.
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Affiliation(s)
- Matthias Ballmaier
- Department of Paediatric Haematology and Oncology, Hannover Medical School, Hannover, Germany.
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19
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Fox NE, Chen R, Hitchcock I, Keates-Baleeiro J, Frangoul H, Geddis AE. Compound heterozygous c-Mpl mutations in a child with congenital amegakaryocytic thrombocytopenia: functional characterization and a review of the literature. Exp Hematol 2009; 37:495-503. [PMID: 19302922 DOI: 10.1016/j.exphem.2009.01.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 01/06/2009] [Accepted: 01/07/2009] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To genetically and functionally characterize mutations of c-Mpl that lead to thrombocytopenia in a child with congenital amegakaryocytic thrombocytopenia. MATERIALS AND METHODS We identified two c-Mpl mutations in a child with clinical features of congenital amegakaryocytic thrombocytopenia, one a previously described mutation in the extracellular domain (R102P) and the other a novel mutation leading to truncation of the receptor after the box 1 homology domain (541Stop). Cell line models were created to examine the ability of the mutant receptors to signal in response to thrombopoietin and thrombopoietin-like agonists. RESULTS Data from cell-line models indicate that c-Mpl R102P does not support significant signaling in response to thrombopoietin due to impaired trafficking of the mutant receptor to the cell surface. Alternative thrombopoietic agents do not circumvent this block to signaling, likely due to the inaccessibility of the receptor. In addition, previous data indicate that c-Mpl 541Stop does not support intracellular signaling due to the loss of critical intracellular domains. CONCLUSIONS This case demonstrates two different mechanisms by which c-Mpl mutations can impair thrombopoietin signaling, and suggests that mutations in the extracellular domain will not be rescued by c-Mpl agonists if they interfere with normal receptor expression.
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Affiliation(s)
- Norma E Fox
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92017, USA
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