1
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Attar LJ, Alelaimat A, Alshorman A, Aladily TN. MPIG6B Gene-Related Myelofibrosis: A Rare Inherited Disease That Is Frequently Described in Arab Population. Avicenna J Med 2024; 14:69-72. [PMID: 38694137 PMCID: PMC11057892 DOI: 10.1055/s-0044-1779697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024] Open
Abstract
The megakaryocyte and platelet inhibitory receptor gene G6P (MPIG6B) is located on chromosome 6p21.33. It encodes G6b-B; an inhibitory receptor expressed on the surface of platelets. It regulates platelets production, aggregation, and activation. We describe a case of a 31-year-old man who presented with a long history of thrombocytopenia, anemia, and hepatosplenomegaly. The patient received multiple blood transfusions and his clinical course was stable. A bone marrow biopsy showed morphologic features similar to primary myelofibrosis. Whole exome sequencing study was performed and revealed homozygous pathogenic mutation in exon 2 of MPIG6B gene (c.324C > A, p.Cys108Ter) that is the second reported case in literature. In this report, we describe the main clinical and pathologic features of this disease and review the literature of previously documented cases.
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Affiliation(s)
- Leen Jihad Attar
- Department of Hematopathology, The University of Jordan, Amman, Jordan
| | | | - Alaa Alshorman
- Department of Hematology, Ministry of Health, Amman, Jordan
| | - Tariq N. Aladily
- Department of Hematopathology, The University of Jordan, Amman, Jordan
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2
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Yenwongfai LN, Arora R, Smith AP, Kalfa T, Husami A, Radulescu V, Myers K, Lorsbach R. Pediatric myelofibrosis due to compound heterozygous MPIG6B mutations in a patient of European ancestry. Pediatr Blood Cancer 2023; 70:e30023. [PMID: 36184776 DOI: 10.1002/pbc.30023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 09/01/2022] [Accepted: 09/05/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Leonard N Yenwongfai
- Department of Pathology and Laboratory Medicine, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Ranjana Arora
- Department of Pathology and Laboratory Medicine, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Alexander P Smith
- Department of Pathology and Laboratory Medicine, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | | | | | - Vlad Radulescu
- Pediatric Hematology and Oncology, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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3
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Mazharian A, Maître B, Bornert A, Hennequin D, Lourenco-Rodrigues M, Geer MJ, Smith CW, Heising S, Walter M, Montel F, Walker LSK, de la Salle H, Watson SP, Gachet C, Senis YA. Treatment of congenital thrombocytopenia and decreased collagen reactivity in G6b-B-deficient mice. Blood Adv 2023; 7:46-59. [PMID: 36269841 PMCID: PMC9813534 DOI: 10.1182/bloodadvances.2022008873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/15/2022] [Accepted: 09/22/2022] [Indexed: 01/18/2023] Open
Abstract
Mice lacking the immunoreceptor tyrosine-based inhibition motif-containing co-inhibitory receptor G6b-B (Mpig6b, G6b knockout, KO) are born with a complex megakaryocyte (MK) per platelet phenotype, characterized by severe macrothrombocytopenia, expansion of the MK population, and focal myelofibrosis in the bone marrow and spleen. Platelets are almost completely devoid of the glycoprotein VI (GPVI)-FcRγ-chain collagen receptor complex, have reduced collagen integrin α2β1, elevated Syk tyrosine kinase activity, and a subset has increased surface immunoglobulins. A similar phenotype was recently reported in patients with null and loss-of-function mutations in MPIG6B. To better understand the cause and treatment of this pathology, we used pharmacological- and genetic-based approaches to rescue platelet counts and function in G6b KO mice. Intravenous immunoglobulin resulted in a transient partial recovery of platelet counts, whereas immune deficiency did not affect platelet counts or receptor expression in G6b KO mice. Syk loss-of-function (R41A) rescued macrothrombocytopenia, GPVI and α2β1 expression in G6b KO mice, whereas treatment with the Syk kinase inhibitor BI1002494 partially rescued platelet count but had no effect on GPVI and α2β1 expression or bleeding. The Src family kinase inhibitor dasatinib was not beneficial in G6b KO mice. In contrast, treatment with the thrombopoietin mimetic romiplostim rescued thrombocytopenia, GPVI expression, and platelet reactivity to collagen, suggesting that it may be a promising therapeutic option for patients lacking functional G6b-B. Intriguingly, GPVI and α2β1 expression were significantly downregulated in romiplostim-treated wild-type mice, whereas GPVI was upregulated in romiplostim-treated G6b KO mice, suggesting a cell intrinsic feedback mechanism that autoregulates platelet reactivity depending on physiological needs.
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Affiliation(s)
- Alexandra Mazharian
- Université de Strasbourg, INSERM, Etablissement Français du Sang Grand-Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Blandine Maître
- Université de Strasbourg, INSERM, Etablissement Français du Sang Grand-Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Alicia Bornert
- Université de Strasbourg, INSERM, Etablissement Français du Sang Grand-Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Desline Hennequin
- Université de Strasbourg, INSERM, Etablissement Français du Sang Grand-Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Marc Lourenco-Rodrigues
- Université de Strasbourg, INSERM, Etablissement Français du Sang Grand-Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Mitchell J. Geer
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, NYU Langone Health, New York, NY
| | - Christopher W. Smith
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Silke Heising
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Michaela Walter
- Boehringer Ingelheim Pharma GmbH and Company KG, Ingelheim, Germany
| | - Florian Montel
- Boehringer Ingelheim Pharma GmbH and Company KG, Ingelheim, Germany
| | - Lucy S. K. Walker
- Division of Infection and Immunity, Institute of Immunity and Transplantation, University College London, Royal Free Campus, London, United Kingdom
| | - Henri de la Salle
- Université de Strasbourg, INSERM, Etablissement Français du Sang Grand-Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Steve P. Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Christian Gachet
- Université de Strasbourg, INSERM, Etablissement Français du Sang Grand-Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Yotis A. Senis
- Université de Strasbourg, INSERM, Etablissement Français du Sang Grand-Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
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4
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Wang Z, Tao F, Yang L, Song N, Teng J, Lu W, Qi S, Chen Z, Xiong H. A novel MPIG6B gene mutation in an adolescent girl with congenital thrombocytopenia and myelofibrosis. Curr Res Transl Med 2022; 70:103355. [PMID: 35940081 DOI: 10.1016/j.retram.2022.103355] [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: 10/14/2021] [Revised: 04/15/2022] [Accepted: 05/31/2022] [Indexed: 01/31/2023]
Abstract
The MPIG6B gene, which encodes G6b-B, regulates platelet production, aggregation, and activation. Loss-of-function of G6b-B can cause thrombocytopenia, myelofibrosis, and anemia in both humans and mice. Several pathogenic MPIG6B mutations have been reported, such as c.324C>A (p.C108*), c.61_61+1dup (p.Ala21GlyfsX159), c.149dup (p.Ala52GlyfsX128), G6b c.469G>A (p.Gly157Arg) c.392delC (p.P134Lfs*10), and c523C>T(p.Arg175Ter). We have added to this database by reporting a new homozygous nonsense mutation (c.420T>A(p.Tyr140Ter)) of MPIG6B in a 14-year-old girl who presented with pallor, scattered cutaneous petechia of the limb, thrombocytopenia, anemia and myelofibrosis. This novel MPIG6B gene mutation encodes a shorter mutated G6b-B that does contain the transmembrane region immunoreceptor tyrosine-based inhibitory motif. The patient was effectively treated with allogeneic hematopoietic stem cell transplantation with peripheral stem cells from a matched unrelated donor. Her symptoms and the MPIG6B mutation disappeared after treatment, and she was healthy and had returned to school at the last follow-up.
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Affiliation(s)
- Zhuo Wang
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China
| | - Fang Tao
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China
| | - Li Yang
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China
| | - Na Song
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China
| | - Juxian Teng
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China
| | - Wenjie Lu
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China
| | - Shanshan Qi
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China
| | - Zhi Chen
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China
| | - Hao Xiong
- Department of Hematology and Oncology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430016, Hubei Province, PR China.
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5
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Warren JT, Di Paola J. Genetics of inherited thrombocytopenias. Blood 2022; 139:3264-3277. [PMID: 35167650 PMCID: PMC9164741 DOI: 10.1182/blood.2020009300] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 02/04/2022] [Indexed: 01/19/2023] Open
Abstract
The inherited thrombocytopenia syndromes are a group of disorders characterized primarily by quantitative defects in platelet number, though with a variety demonstrating qualitative defects and/or extrahematopoietic findings. Through collaborative international efforts applying next-generation sequencing approaches, the list of genetic syndromes that cause thrombocytopenia has expanded significantly in recent years, now with over 40 genes implicated. In this review, we focus on what is known about the genetic etiology of inherited thrombocytopenia syndromes and how the field has worked to validate new genetic discoveries. We highlight the important role for the clinician in identifying a germline genetic diagnosis and strategies for identifying novel causes through research-based endeavors.
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Affiliation(s)
- Julia T Warren
- Division of Hematology-Oncology, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO
| | - Jorge Di Paola
- Division of Hematology-Oncology, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO
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6
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G6b-B regulates an essential step in megakaryocyte maturation. Blood Adv 2022; 6:3155-3161. [PMID: 35134123 PMCID: PMC9131916 DOI: 10.1182/bloodadvances.2021006151] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/20/2022] [Indexed: 12/05/2022] Open
Abstract
Loss of G6b-B leads to an unexpected megakaryocyte development defect resulting in severe macrothrombocytopenia. G6b-B–deficient mice display reduced levels of MK-specific transcripts, surface receptors, GATA-1, and thrombopoietin signaling.
G6b-B is a megakaryocyte lineage-specific immunoreceptor tyrosine-based inhibition motif–containing receptor, essential for platelet homeostasis. Mice with a genomic deletion of the entire Mpig6b locus develop severe macrothrombocytopenia and myelofibrosis, which is reflected in humans with null mutations in MPIG6B. The current model proposes that megakaryocytes lacking G6b-B develop normally, whereas proplatelet release is hampered, but the underlying molecular mechanism remains unclear. We report on a spontaneous recessive single nucleotide mutation in C57BL/6 mice, localized within the intronic region of the Mpig6b locus that abolishes G6b-B expression and reproduces macrothrombocytopenia, myelofibrosis, and osteosclerosis. As the mutation is based on a single-nucleotide exchange, Mpig6bmut mice represent an ideal model to study the role of G6b-B. Megakaryocytes from these mice were smaller, displayed a less-developed demarcation membrane system, and had a reduced expression of receptors. RNA sequencing revealed a striking global reduction in the level of megakaryocyte-specific transcripts, in conjunction with decreased protein levels of the transcription factor GATA-1 and impaired thrombopoietin signaling. The reduced number of mature MKs in the bone marrow was corroborated on a newly developed Mpig6b-null mouse strain. Our findings highlight an unexpected essential role of G6b-B in the early differentiation within the megakaryocytic lineage.
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7
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ASXL2 mutated myelodysplastic syndrome in a novel germline G6b variant. Leuk Res Rep 2022; 17:100303. [PMID: 35330689 PMCID: PMC8938321 DOI: 10.1016/j.lrr.2022.100303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 03/07/2022] [Accepted: 03/16/2022] [Indexed: 11/22/2022] Open
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8
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Bone marrow microenvironment of MPN cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021. [PMID: 34756245 DOI: 10.1016/bs.ircmb.2021.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/10/2023]
Abstract
In this chapter, we will discuss the current knowledge concerning the alterations of the cellular components in the bone marrow niche in Myeloproliferative Neoplasms (MPNs), highlighting the central role of the megakaryocytes in MPN progression, and the extracellular matrix components characterizing the fibrotic bone marrow.
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9
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Collins J, Astle WJ, Megy K, Mumford AD, Vuckovic D. Advances in understanding the pathogenesis of hereditary macrothrombocytopenia. Br J Haematol 2021; 195:25-45. [PMID: 33783834 DOI: 10.1111/bjh.17409] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/19/2021] [Indexed: 12/14/2022]
Abstract
Low platelet count, or thrombocytopenia, is a common haematological abnormality, with a wide differential diagnosis, which may represent a clinically significant underlying pathology. Macrothrombocytopenia, the presence of large platelets in combination with thrombocytopenia, can be acquired or hereditary and indicative of a complex disorder. In this review, we discuss the interpretation of platelet count and volume measured by automated haematology analysers and highlight some important technical considerations relevant to the analysis of blood samples with macrothrombocytopenia. We review how large cohorts, such as the UK Biobank and INTERVAL studies, have enabled an accurate description of the distribution and co-variation of platelet parameters in adult populations. We discuss how genome-wide association studies have identified hundreds of genetic associations with platelet count and mean platelet volume, which in aggregate can explain large fractions of phenotypic variance, consistent with a complex genetic architecture and polygenic inheritance. Finally, we describe the large genetic diagnostic and discovery programmes, which, simultaneously to genome-wide association studies, have expanded the repertoire of genes and variants associated with extreme platelet phenotypes. These have advanced our understanding of the pathogenesis of hereditary macrothrombocytopenia and support a future clinical diagnostic strategy that utilises genotype alongside clinical and laboratory phenotype data.
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Affiliation(s)
- Janine Collins
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
- Department of Haematology, Barts Health NHS Trust, London, UK
| | - William J Astle
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
- MRC Biostatistics Unit, University of Cambridge, Cambridge Institute of Public Health, Forvie Site, Robinson Way, Cambridge, UK
| | - Karyn Megy
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Andrew D Mumford
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Dragana Vuckovic
- Department of Biostatistics and Epidemiology, Faculty of Medicine, Imperial College London, London, UK
- Human Genetics, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
- National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Donor Health and Genomics, University of Cambridge, Cambridge, UK
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10
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Myeloproliferative Disorders and its Effect on Bone Homeostasis: The Role of Megakaryocytes. Blood 2021; 139:3127-3137. [PMID: 34428274 DOI: 10.1182/blood.2021011480] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 08/11/2021] [Indexed: 11/20/2022] Open
Abstract
Myeloproliferative Neoplasms (MPNs) are a heterogeneous group of chronic hematological diseases that arise from the clonal expansion of abnormal hematopoietic stem cells, of which Polycythemia Vera (PV), Essential Thrombocythemia (ET), and Primary Myelofibrosis (PMF) have been extensively reviewed in context of clonal expansion, fibrosis and other phenotypes. Here, we review current knowledge on the influence of different forms of MPN on bone health. Studies implicated various degrees of effect of different forms of MPN on bone density, and on osteoblast proliferation and differentiation, using murine models and human data. The majority of studies show that bone volume is generally increased in PMF patients, whereas it is slightly decreased or not altered in ET and PV patients, although possible differences between male and female phenotypes were not fully explored in most MPN forms. Osteosclerosis seen in PMF patients is a serious complication that can lead to bone marrow failure, and the loss of bone reported in some ET and PV patients can lead to osteoporotic fractures. Some MPN forms are associated with increased number of megakaryocytes (MKs), and several of the MK-associated factors in MPN are known to affect bone development. Here, we review known mechanisms involved in these processes, with focus on the role of MKs and secreted factors. Understanding MPN-associated changes in bone health could improve early intervention and treatment of this side effect of the pathology.
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Batis H, Almugairi A, Almugren O, Aljabry M, Alqahtani F, Elbashir E, Elfaki M, Alsultan A. Detrimental variants in MPIG6B in two children with myelofibrosis: Does immune dysregulation contribute to myelofibrosis? Pediatr Blood Cancer 2021; 68:e29062. [PMID: 33871931 DOI: 10.1002/pbc.29062] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/29/2021] [Accepted: 03/30/2021] [Indexed: 12/26/2022]
Affiliation(s)
- Hasan Batis
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Oncology Center, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Areej Almugairi
- Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City and National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Omar Almugren
- Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mansour Aljabry
- Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Fatima Alqahtani
- Department of Pathology and Laboratory Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Enas Elbashir
- Department of Pediatric Hematology/Oncology, King Abdullah Specialist Children's Hospital, Riyadh, Saudi Arabia
| | - Mohammed Elfaki
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Oncology Center, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Abdulrahman Alsultan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Oncology Center, King Saud University Medical City, Riyadh, Saudi Arabia
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12
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Inherited Platelet Disorders: An Updated Overview. Int J Mol Sci 2021; 22:ijms22094521. [PMID: 33926054 PMCID: PMC8123627 DOI: 10.3390/ijms22094521] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/17/2021] [Accepted: 04/21/2021] [Indexed: 02/06/2023] Open
Abstract
Platelets play a major role in hemostasis as ppwell as in many other physiological and pathological processes. Accordingly, production of about 1011 platelet per day as well as appropriate survival and functions are life essential events. Inherited platelet disorders (IPDs), affecting either platelet count or platelet functions, comprise a heterogenous group of about sixty rare diseases caused by molecular anomalies in many culprit genes. Their clinical relevance is highly variable according to the specific disease and even within the same type, ranging from almost negligible to life-threatening. Mucocutaneous bleeding diathesis (epistaxis, gum bleeding, purpura, menorrhagia), but also multisystemic disorders and/or malignancy comprise the clinical spectrum of IPDs. The early and accurate diagnosis of IPDs and a close patient medical follow-up is of great importance. A genotype-phenotype relationship in many IPDs makes a molecular diagnosis especially relevant to proper clinical management. Genetic diagnosis of IPDs has been greatly facilitated by the introduction of high throughput sequencing (HTS) techniques into mainstream investigation practice in these diseases. However, there are still unsolved ethical concerns on general genetic investigations. Patients should be informed and comprehend the potential implications of their genetic analysis. Unlike the progress in diagnosis, there have been no major advances in the clinical management of IPDs. Educational and preventive measures, few hemostatic drugs, platelet transfusions, thrombopoietin receptor agonists, and in life-threatening IPDs, allogeneic hematopoietic stem cell transplantation are therapeutic possibilities. Gene therapy may be a future option. Regular follow-up by a specialized hematology service with multidisciplinary support especially for syndromic IPDs is mandatory.
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13
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Stavnichuk M, Tauer JT, Nagy Z, Mazharian A, Welman M, Lordkipanidzé M, Senis YA, Komarova SV. Severity of Megakaryocyte-Driven Osteosclerosis in Mpig6b-Deficient Mice Is Sex-Linked. J Bone Miner Res 2021; 36:803-813. [PMID: 33434328 DOI: 10.1002/jbmr.4245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/16/2020] [Accepted: 12/29/2020] [Indexed: 01/15/2023]
Abstract
Patients with chronic myelofibrosis often suffer from osteosclerosis, which is associated with bone pain and may lead to bone marrow failure. The pathogenesis of myelofibrosis is linked to aberrant megakaryocyte development and function. Null and loss-of-function mutations in MPIG6B, which codes for the inhibitory heparan sulfate receptor G6b-B, result in severe macrothrombocytopenia, large megakaryocyte clusters, and focal primary myelofibrosis in mice and humans. We investigated the development of osteosclerosis in Mpig6b null (Mpig6b-/- ) mice. Although male and female Mpig6b-/- mice presented with elevated bone marrow megakaryocyte number and macrothrombocytopenia, female Mpig6b-/- mice developed progressive splenomegaly starting at 8 weeks of age. Micro-computed tomography (μCT) of femurs showed that female Mpig6b-/- mice had increased cortical thickness and reduced bone marrow area starting at 8 weeks of age and developed occlusion of the medullary cavity by trabeculae by 16 weeks of age. In contrast, male Mpig6b-/- mice developed only a small number of trabeculae in the medullary cavity at the proximal diaphysis and demonstrated a temporary decrease in bone volume fraction and trabecular thickness at 16 weeks. Ovariectomy of 10-week-old female Mpig6b-/- mice prevented the development of medullary cavity osteosclerosis, whereas orchiectomy of male Mpig6b-/- mice did not exacerbate their disease. Importantly, ovariectomized female Mpig6b-/- mice also demonstrated improvement in spleen weight compared to sham-operated Mpig6b-/- mice, establishing estrogen as a contributing factor to the severity of the megakaryocyte-driven osteosclerosis. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Mariya Stavnichuk
- Department of Biological and Biomedical Engineering, McGill University, Montreal, QC, Canada.,Shriners Hospital for Children-Canada, Montreal, QC, Canada
| | - Josephine T Tauer
- Shriners Hospital for Children-Canada, Montreal, QC, Canada.,Faculty of Dentistry, McGill University, Montreal, QC, Canada
| | - Zoltan Nagy
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | - Alexandra Mazharian
- Université de Strasbourg, Institut National de la Santé et de la Recherche Médicale (INSERM), Etablissement Français du Sang Grand Est, Unité Mixte de Recherche (UMR)-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Mélanie Welman
- Research Center, Montreal Heart Institute, Montreal, QC, Canada
| | - Marie Lordkipanidzé
- Research Center, Montreal Heart Institute, Montreal, QC, Canada.,Faculty of Pharmacy, University of Montreal, Montreal, QC, Canada
| | - Yotis A Senis
- Université de Strasbourg, Institut National de la Santé et de la Recherche Médicale (INSERM), Etablissement Français du Sang Grand Est, Unité Mixte de Recherche (UMR)-S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Svetlana V Komarova
- Department of Biological and Biomedical Engineering, McGill University, Montreal, QC, Canada.,Shriners Hospital for Children-Canada, Montreal, QC, Canada.,Faculty of Dentistry, McGill University, Montreal, QC, Canada
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Soriano Jerez EM, Gibbins JM, Hughes CE. Targeting platelet inhibition receptors for novel therapies: PECAM-1 and G6b-B. Platelets 2021; 32:761-769. [PMID: 33646086 DOI: 10.1080/09537104.2021.1882668] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
While current oral antiplatelet therapies benefit many patients, they deregulate the hemostatic balance leaving patients at risk of systemic side-effects such as hemorrhage. Dual antiplatelet treatment is the standard approach, combining aspirin with P2Y12 blockers. These therapies mainly target autocrine activation mechanisms (TxA2, ADP) and, more recently, the use of thrombin or thrombin receptor antagonists have been added to the available approaches. Recent efforts to develop new classes of anti-platelet drugs have begun to focus on primary platelet activation pathways such as through the immunoreceptor tyrosine-based activation motif (ITAM)-containing collagen receptor GPVI/FcRγ-chain complex. There are already encouraging results from targeting GPVI, with reduced aggregation and smaller arterial thrombi, without major bleeding complications, likely due to overlapping activation signaling pathways with other receptors such as the GPIb-V-IX complex. An alternative approach to reduce platelet activation could be to inhibit this signaling pathway by targeting the inhibitory pathways intrinsic to platelets. Stimulation of endogenous negative modulators could provide more specific inhibition of platelet function, but is this feasible? In this review, we explore the potential of the two major platelet immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing inhibitory receptors, G6b-B and PECAM-1, as antithrombotic targets.
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Affiliation(s)
- Eva M Soriano Jerez
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, UK.,Institute of Experimental Biomedicine, University Hospital Würzburg and Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Jonathan M Gibbins
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, UK
| | - Craig E Hughes
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, UK
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15
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Learning the Ropes of Platelet Count Regulation: Inherited Thrombocytopenias. J Clin Med 2021; 10:jcm10030533. [PMID: 33540538 PMCID: PMC7867147 DOI: 10.3390/jcm10030533] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 02/06/2023] Open
Abstract
Inherited thrombocytopenias (IT) are a group of hereditary disorders characterized by a reduced platelet count sometimes associated with abnormal platelet function, which can lead to bleeding but also to syndromic manifestations and predispositions to other disorders. Currently at least 41 disorders caused by mutations in 42 different genes have been described. The pathogenic mechanisms of many forms of IT have been identified as well as the gene variants implicated in megakaryocyte maturation or platelet formation and clearance, while for several of them the pathogenic mechanism is still unknown. A range of therapeutic approaches are now available to improve survival and quality of life of patients with IT; it is thus important to recognize an IT and establish a precise diagnosis. ITs may be difficult to diagnose and an initial accurate clinical evaluation is mandatory. A combination of clinical and traditional laboratory approaches together with advanced sequencing techniques provide the highest rate of diagnostic success. Despite advancement in the diagnosis of IT, around 50% of patients still do not receive a diagnosis, therefore further research in the field of ITs is warranted to further improve patient care.
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16
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Salama ME. Important Pathologic Considerations for Establishing the Diagnosis of Myelofibrosis. Hematol Oncol Clin North Am 2021; 35:267-278. [PMID: 33641868 DOI: 10.1016/j.hoc.2020.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Diagnostic criteria for primary myelofibrosis as defined by the 2017 revised World Health Organization (WHO) classification system incorporate clinical and laboratory findings, including driver mutational status (JAK2, MPL, CALR. and triple negative). The WHO emphasized the role of histopathology in making an accurate diagnosis of primary myelofibrosis and successfully incorporated a fibrosis scoring system and scoring schemas for collagen fibrosis and osteosclerosis. These steps represent a significant addition to the standardization of myelofibrosis evaluation and minimize the risk for misdiagnosis. This article reviews important pathologic considerations along with highlights of potentially relevant pitfalls relevant to histopathological diagnosis of myelofibrosis.
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Affiliation(s)
- Mohamed E Salama
- Department of Laboratory Medicine and Pathology, Division of Hematopathology, Mayo Clinic School of Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA.
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17
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Interplay between the tyrosine kinases Chk and Csk and phosphatase PTPRJ is critical for regulating platelets in mice. Blood 2020; 135:1574-1587. [PMID: 32016283 DOI: 10.1182/blood.2019002848] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 01/06/2020] [Indexed: 12/17/2022] Open
Abstract
The Src family kinases (SFKs) Src, Lyn, and Fyn are essential for platelet activation and also involved in megakaryocyte (MK) development and platelet production. Platelet SFKs are inhibited by C-terminal Src kinase (Csk), which phosphorylates a conserved tyrosine in their C-terminal tail, and are activated by the receptor-type tyrosine phosphatase PTPRJ (CD148, DEP-1), which dephosphorylates the same residue. Deletion of Csk and PTPRJ in the MK lineage in mice results in increased SFK activity, but paradoxically hypoactive platelets resulting from negative feedback mechanisms, including upregulation of Csk homologous kinase (Chk) expression. Here, we investigate the role of Chk in platelets, functional redundancy with Csk, and the physiological consequences of ablating Chk, Csk, and PTPRJ in mice. Platelet count was normal in Chk knockout (KO) mice, reduced by 92% in Chk;Csk double KO (DKO) mice, and partially rescued in Chk;Csk;Ptprj triple KO (TKO) mice. Megakaryocyte numbers were significantly increased in both DKO and TKO mice. Phosphorylation of the inhibitory tyrosine of SFKs was almost completely abolished in DKO platelets, which was partially rescued in Src and Fyn in TKO platelets. This residual phosphorylation was abolished by Src inhibitors, revealing an unexpected mechanism in which SFKs autoinhibit their activity by phosphorylating their C-terminal tyrosine residues. We demonstrate that reduced inhibitory phosphorylation of SFKs leads to thrombocytopenia, with Csk being the dominant inhibitor in platelets and Chk having an auxiliary role. PTPRJ deletion in addition to Chk and Csk ameliorates the extent of thrombocytopenia, suggesting targeting it may have therapeutic benefits in such conditions.
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18
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Pecci A, Balduini CL. Inherited thrombocytopenias: an updated guide for clinicians. Blood Rev 2020; 48:100784. [PMID: 33317862 DOI: 10.1016/j.blre.2020.100784] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/05/2020] [Accepted: 10/28/2020] [Indexed: 02/06/2023]
Abstract
The great advances in the knowledge of inherited thrombocytopenias (ITs) made since the turn of the century have significantly changed our view of these conditions. To date, ITs encompass 45 disorders with different degrees of complexity of the clinical picture and very wide variability in the prognosis. They include forms characterized by thrombocytopenia alone, forms that present with other congenital defects, and conditions that predispose to acquire additional diseases over the course of life. In this review, we recapitulate the clinical features of ITs with emphasis on the forms predisposing to additional diseases. We then discuss the key issues for a rational approach to the diagnosis of ITs in clinical practice. Finally, we aim to provide an updated and comprehensive guide to the treatment of ITs, including the management of hemostatic challenges, the treatment of severe forms, and the approach to the manifestations that add to thrombocytopenia.
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Affiliation(s)
- Alessandro Pecci
- Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy.
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19
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Abstract
PURPOSE OF REVIEW The increasing use of high throughput sequencing and genomic analysis has facilitated the discovery of new causes of inherited platelet disorders. Studies of these disorders and their respective mouse models have been central to understanding their biology, and also in revealing new aspects of platelet function and production. This review covers recent contributions to the identification of genes, proteins and variants associated with inherited platelet defects, and highlights how these studies have provided insights into platelet development and function. RECENT FINDINGS Novel genes recently implicated in human platelet dysfunction include the galactose metabolism enzyme UDP-galactose-4-epimerase in macrothrombocytopenia, and erythropoietin-producing hepatoma-amplified sequence receptor transmembrane tyrosine kinase EPHB2 in a severe bleeding disorder with deficiencies in platelet agonist response and granule secretion. Recent studies of disease-associated variants established or clarified roles in platelet function and/or production for the membrane receptor G6b-B, the FYN-binding protein FYB1/ADAP, the RAS guanyl-releasing protein RASGRP2/CalDAG-GEFI and the receptor-like protein tyrosine phosphatase PTPRJ/CD148. Studies of genes associated with platelet disorders advanced understanding of the cellular roles of neurobeachin-like 2, as well as several genes influenced by the transcription regulator RUNT-related transcription factor 1 (RUNX1), including NOTCH4. SUMMARY The molecular bases of many hereditary platelet disorders have been elucidated by the application of recent advances in cell imaging and manipulation, genomics and protein function analysis. These techniques have also aided the detection of new disorders, and enabled studies of disease-associated genes and variants to enhance understanding of platelet development and function.
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20
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Human models of NUP98-KDM5A megakaryocytic leukemia in mice contribute to uncovering new biomarkers and therapeutic vulnerabilities. Blood Adv 2020; 3:3307-3321. [PMID: 31698461 DOI: 10.1182/bloodadvances.2019030981] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 08/11/2019] [Indexed: 12/13/2022] Open
Abstract
Acute megakaryoblastic leukemia (AMKL) represents ∼10% of pediatric acute myeloid leukemia cases and typically affects young children (<3 years of age). It remains plagued with extremely poor treatment outcomes (<40% cure rates), mostly due to primary chemotherapy refractory disease and/or early relapse. Recurrent and mutually exclusive chimeric fusion oncogenes have been detected in 60% to 70% of cases and include nucleoporin 98 (NUP98) gene rearrangements, most commonly NUP98-KDM5A. Human models of NUP98-KDM5A-driven AMKL capable of faithfully recapitulating the disease have been lacking, and patient samples are rare, further limiting biomarkers and drug discovery. To overcome these impediments, we overexpressed NUP98-KDM5A in human cord blood hematopoietic stem and progenitor cells using a lentiviral-based approach to create physiopathologically relevant disease models. The NUP98-KDM5A fusion oncogene was a potent inducer of maturation arrest, sustaining long-term proliferative and progenitor capacities of engineered cells in optimized culture conditions. Adoptive transfer of NUP98-KDM5A-transformed cells into immunodeficient mice led to multiple subtypes of leukemia, including AMKL, that phenocopy human disease phenotypically and molecularly. The integrative molecular characterization of synthetic and patient NUP98-KDM5A AMKL samples revealed SELP, MPIG6B, and NEO1 as distinctive and novel disease biomarkers. Transcriptomic and proteomic analyses pointed to upregulation of the JAK-STAT signaling pathway in the model AMKL. Both synthetic models and patient-derived xenografts of NUP98-rearranged AMKL showed in vitro therapeutic vulnerability to ruxolitinib, a clinically approved JAK2 inhibitor. Overall, synthetic human AMKL models contribute to defining functional dependencies of rare genotypes of high-fatality pediatric leukemia, which lack effective and rationally designed treatments.
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21
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Saliba AN, Ferrer A, Gangat N, Pruthi RK, Tefferi A, Higgins A, Bezerra ED, Buglioni A, Salama ME, Klee EW, Pinto E Vairo F, Mangaonkar A, Majerus J, Chen D, Patnaik MM. Aetiology and outcomes of secondary myelofibrosis occurring in the context of inherited platelet disorders: A single institutional study of four patients. Br J Haematol 2020; 190:e316-e320. [PMID: 32567678 DOI: 10.1111/bjh.16897] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Alejandro Ferrer
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | | | | | | | | | | | - Alessia Buglioni
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Mohamed E Salama
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Filippo Pinto E Vairo
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | | | - Julie Majerus
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Dong Chen
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
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22
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Nurden AT, Nurden P. Inherited thrombocytopenias: history, advances and perspectives. Haematologica 2020; 105:2004-2019. [PMID: 32527953 PMCID: PMC7395261 DOI: 10.3324/haematol.2019.233197] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/08/2020] [Indexed: 12/11/2022] Open
Abstract
Over the last 100 years the role of platelets in hemostatic events and their production by megakaryocytes have gradually been defined. Progressively, thrombocytopenia was recognized as a cause of bleeding, first through an acquired immune disorder; then, since 1948, when Bernard-Soulier syndrome was first described, inherited thrombocytopenia became a fascinating example of Mendelian disease. The platelet count is often severely decreased and platelet size variable; associated platelet function defects frequently aggravate bleeding. Macrothrombocytopenia with variable proportions of enlarged platelets is common. The number of circulating platelets will depend on platelet production, consumption and lifespan. The bulk of macrothrombocytopenias arise from defects in megakaryopoiesis with causal variants in transcription factor genes giving rise to altered stem cell differentiation and changes in early megakaryocyte development and maturation. Genes encoding surface receptors, cytoskeletal and signaling proteins also feature prominently and Sanger sequencing associated with careful phenotyping has allowed their early classification. It quickly became apparent that many inherited thrombocytopenias are syndromic while others are linked to an increased risk of hematologic malignancies. In the last decade, the application of next-generation sequencing, including whole exome sequencing, and the use of gene platforms for rapid testing have greatly accelerated the discovery of causal genes and extended the list of variants in more common disorders. Genes linked to an increased platelet turnover and apoptosis have also been identified. The current challenges are now to use next-generation sequencing in first-step screening and to define bleeding risk and treatment better.
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Affiliation(s)
- Alan T Nurden
- Institut Hospitalo-Universitaire LIRYC, Pessac, France
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23
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Chen H, Zheng J, Chen Z, Ma H, Zhang R, Wu R. Case report of a novel MPIG6B gene mutation in a Chinese boy with pancytopenia and splenomegaly. Gene 2019; 715:143957. [DOI: 10.1016/j.gene.2019.143957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/01/2019] [Accepted: 07/01/2019] [Indexed: 12/16/2022]
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24
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Vögtle T, Sharma S, Mori J, Nagy Z, Semeniak D, Scandola C, Geer MJ, Smith CW, Lane J, Pollack S, Lassila R, Jouppila A, Barr AJ, Ogg DJ, Howard TD, McMiken HJ, Warwicker J, Geh C, Rowlinson R, Abbott WM, Eckly A, Schulze H, Wright GJ, Mazharian A, Fütterer K, Rajesh S, Douglas MR, Senis YA. Heparan sulfates are critical regulators of the inhibitory megakaryocyte-platelet receptor G6b-B. eLife 2019; 8:e46840. [PMID: 31436532 PMCID: PMC6742478 DOI: 10.7554/elife.46840] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 08/21/2019] [Indexed: 02/06/2023] Open
Abstract
The immunoreceptor tyrosine-based inhibition motif (ITIM)-containing receptor G6b-B is critical for platelet production and activation. Loss of G6b-B results in severe macrothrombocytopenia, myelofibrosis and aberrant platelet function in mice and humans. Using a combination of immunohistochemistry, affinity chromatography and proteomics, we identified the extracellular matrix heparan sulfate (HS) proteoglycan perlecan as a G6b-B binding partner. Subsequent in vitro biochemical studies and a cell-based genetic screen demonstrated that the interaction is specifically mediated by the HS chains of perlecan. Biophysical analysis revealed that heparin forms a high-affinity complex with G6b-B and mediates dimerization. Using platelets from humans and genetically modified mice, we demonstrate that binding of G6b-B to HS and multivalent heparin inhibits platelet and megakaryocyte function by inducing downstream signaling via the tyrosine phosphatases Shp1 and Shp2. Our findings provide novel insights into how G6b-B is regulated and contribute to our understanding of the interaction of megakaryocytes and platelets with glycans.
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Affiliation(s)
- Timo Vögtle
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Sumana Sharma
- Cell Surface Signalling LaboratoryWellcome Trust Sanger InstituteCambridgeUnited Kingdom
| | - Jun Mori
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Zoltan Nagy
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Daniela Semeniak
- Institute of Experimental BiomedicineUniversity Hospital WürzburgWürzburgGermany
| | - Cyril Scandola
- Université de Strasbourg, Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de StrasbourgStrasbourgFrance
| | - Mitchell J Geer
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Christopher W Smith
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Jordan Lane
- Sygnature Discovery LimitedNottinghamUnited Kingdom
| | | | - Riitta Lassila
- Coagulation Disorders Unit, Department of Hematology, Comprehensive Cancer CenterUniversity of Helsinki, Helsinki University HospitalHelsinkiFinland
- Aplagon OyHelsinkiFinland
| | - Annukka Jouppila
- Coagulation Disorders UnitHelsinki University Hospital Research InstituteHelsinkiFinland
| | - Alastair J Barr
- Department of Biomedical Science, Faculty of Science & TechnologyUniversity of WestminsterLondonUnited Kingdom
| | - Derek J Ogg
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | - Tina D Howard
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | | | - Juli Warwicker
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | - Catherine Geh
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | | | - W Mark Abbott
- Peak Proteins LimitedAlderley ParkCheshireUnited Kingdom
| | - Anita Eckly
- Université de Strasbourg, Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de StrasbourgStrasbourgFrance
| | - Harald Schulze
- Institute of Experimental BiomedicineUniversity Hospital WürzburgWürzburgGermany
| | - Gavin J Wright
- Cell Surface Signalling LaboratoryWellcome Trust Sanger InstituteCambridgeUnited Kingdom
| | - Alexandra Mazharian
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Klaus Fütterer
- School of Biosciences, College of Life and Environmental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Sundaresan Rajesh
- Institute of Cancer and Genomic Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - Michael R Douglas
- Institute of Inflammation and Ageing, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
- Department of NeurologyDudley Group NHS Foundation TrustDudleyUnited Kingdom
- School of Life and Health SciencesAston UniversityBirminghamUnited Kingdom
| | - Yotis A Senis
- Institute of Cardiovascular Sciences, College of Medical and Dental SciencesUniversity of BirminghamBirminghamUnited Kingdom
- Université de Strasbourg, Institut National de la Santé et de la Recherche Médicale, Etablissement Français du Sang Grand Est, Unité Mixte de Recherche-S 1255, Fédération de Médecine Translationnelle de StrasbourgStrasbourgFrance
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25
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Nagy M, van Geffen JP, Stegner D, Adams DJ, Braun A, de Witt SM, Elvers M, Geer MJ, Kuijpers MJE, Kunzelmann K, Mori J, Oury C, Pircher J, Pleines I, Poole AW, Senis YA, Verdoold R, Weber C, Nieswandt B, Heemskerk JWM, Baaten CCFMJ. Comparative Analysis of Microfluidics Thrombus Formation in Multiple Genetically Modified Mice: Link to Thrombosis and Hemostasis. Front Cardiovasc Med 2019; 6:99. [PMID: 31417909 PMCID: PMC6682619 DOI: 10.3389/fcvm.2019.00099] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/03/2019] [Indexed: 12/15/2022] Open
Abstract
Genetically modified mice are indispensable for establishing the roles of platelets in arterial thrombosis and hemostasis. Microfluidics assays using anticoagulated whole blood are commonly used as integrative proxy tests for platelet function in mice. In the present study, we quantified the changes in collagen-dependent thrombus formation for 38 different strains of (genetically) modified mice, all measured with the same microfluidics chamber. The mice included were deficient in platelet receptors, protein kinases or phosphatases, small GTPases or other signaling or scaffold proteins. By standardized re-analysis of high-resolution microscopic images, detailed information was obtained on altered platelet adhesion, aggregation and/or activation. For a subset of 11 mouse strains, these platelet functions were further evaluated in rhodocytin- and laminin-dependent thrombus formation, thus allowing a comparison of glycoprotein VI (GPVI), C-type lectin-like receptor 2 (CLEC2) and integrin α6β1 pathways. High homogeneity was found between wild-type mice datasets concerning adhesion and aggregation parameters. Quantitative comparison for the 38 modified mouse strains resulted in a matrix visualizing the impact of the respective (genetic) deficiency on thrombus formation with detailed insight into the type and extent of altered thrombus signatures. Network analysis revealed strong clusters of genes involved in GPVI signaling and Ca2+ homeostasis. The majority of mice demonstrating an antithrombotic phenotype in vivo displayed with a larger or smaller reduction in multi-parameter analysis of collagen-dependent thrombus formation in vitro. Remarkably, in only approximately half of the mouse strains that displayed reduced arterial thrombosis in vivo, this was accompanied by impaired hemostasis. This was also reflected by comparing in vitro thrombus formation (by microfluidics) with alterations in in vivo bleeding time. In conclusion, the presently developed multi-parameter analysis of thrombus formation using microfluidics can be used to: (i) determine the severity of platelet abnormalities; (ii) distinguish between altered platelet adhesion, aggregation and activation; and (iii) elucidate both collagen and non-collagen dependent alterations of thrombus formation. This approach may thereby aid in the better understanding and better assessment of genetic variation that affect in vivo arterial thrombosis and hemostasis.
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Affiliation(s)
- Magdolna Nagy
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Johanna P van Geffen
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - David Stegner
- Rudolf Virchow Center, Institute of Experimental Biomedicine, University Hospital Würzburg, University of Würzburg, Würzburg, Germany
| | - David J Adams
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Attila Braun
- Rudolf Virchow Center, Institute of Experimental Biomedicine, University Hospital Würzburg, University of Würzburg, Würzburg, Germany
| | - Susanne M de Witt
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Margitta Elvers
- Department of Vascular Surgery, Experimental Vascular Medicine, Heinrich Heine University, Düsseldorf, Germany
| | - Mitchell J Geer
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Marijke J E Kuijpers
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Karl Kunzelmann
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Jun Mori
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Cécile Oury
- GIGA-Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - Joachim Pircher
- Medizinische Klinik und Poliklinik I, Klinikum der Universität München, Ludwig-Maximilians-University, and DZHK (German Center for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
| | - Irina Pleines
- Rudolf Virchow Center, Institute of Experimental Biomedicine, University Hospital Würzburg, University of Würzburg, Würzburg, Germany
| | - Alastair W Poole
- Department of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Yotis A Senis
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Remco Verdoold
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Christian Weber
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands.,Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Bernhard Nieswandt
- Rudolf Virchow Center, Institute of Experimental Biomedicine, University Hospital Würzburg, University of Würzburg, Würzburg, Germany
| | - Johan W M Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Constance C F M J Baaten
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands.,Institute for Molecular Cardiovascular Research (IMCAR), University Hospital Aachen, Aachen, Germany
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26
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Rayes J, Watson SP, Nieswandt B. Functional significance of the platelet immune receptors GPVI and CLEC-2. J Clin Invest 2019; 129:12-23. [PMID: 30601137 DOI: 10.1172/jci122955] [Citation(s) in RCA: 195] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although platelets are best known for their role in hemostasis, they are also crucial in development, host defense, inflammation, and tissue repair. Many of these roles are regulated by the immune-like receptors glycoprotein VI (GPVI) and C-type lectin receptor 2 (CLEC-2), which signal through an immunoreceptor tyrosine-based activation motif (ITAM). GPVI is activated by collagen in the subendothelial matrix, by fibrin and fibrinogen in the thrombus, and by a remarkable number of other ligands. CLEC-2 is activated by the transmembrane protein podoplanin, which is found outside of the vasculature and is upregulated in development, inflammation, and cancer, but there is also evidence for additional ligands. In this Review, we discuss the physiological and pathological roles of CLEC-2 and GPVI and their potential as targets in thrombosis and thrombo-inflammatory disorders (i.e., disorders in which inflammation plays a critical role in the ensuing thrombosis) relative to current antiplatelet drugs.
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Affiliation(s)
- Julie Rayes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Steve P Watson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, United Kingdom
| | - Bernhard Nieswandt
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
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27
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28
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Abstract
In this issue of Blood, Hofmann et al and Geer et al describe signal-transducing properties of G6b-B that are required for normal platelet production by megakaryocytes in both humans and mice.1,2
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29
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Uncoupling ITIM receptor G6b-B from tyrosine phosphatases Shp1 and Shp2 disrupts murine platelet homeostasis. Blood 2018; 132:1413-1425. [PMID: 29891536 DOI: 10.1182/blood-2017-10-802975] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 06/05/2018] [Indexed: 01/08/2023] Open
Abstract
The immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing receptor G6b-B has emerged as a key regulator of platelet homeostasis. However, it remains unclear how it mediates its effects. Tyrosine phosphorylation of ITIM and immunoreceptor tyrosine-based switch motif (ITSM) within the cytoplasmic tail of G6b-B provides a docking site for Src homology 2 domain-containing protein-tyrosine phosphatases Shp1 and Shp2, which are also critical regulators of platelet production and function. In this study, we investigate the physiological consequences of uncoupling G6b-B from Shp1 and Shp2. To address this, we generated a transgenic mouse model expressing a mutant form of G6b-B in which tyrosine residues 212 and 238 within ITIM and ITSM were mutated to phenylalanine. Mice homozygous for the mutation (G6b-B diY/F) were macrothrombocytopenic, as a result of the reduction in platelet production, and had large clusters of megakaryocytes and myelofibrosis at sites of hematopoiesis, similar to those observed in G6b-deficient mice and patients. Platelets from G6b-B diY/F mice were hyporesponsive to collagen, as a result of the significant reduction in the expression of the immunoreceptor tyrosine-based activation motif (ITAM)-containing collagen receptor complex GPVI-FcR γ-chain, as well as thrombin, which could be partially rescued by costimulating the platelets with adenosine diphosphate. In contrast, platelets from G6b-B diY/F, G6b KO, and megakaryocyte-specific Shp2 KO mice were hyperresponsive to antibody-mediated cross-linking of the hemi-ITAM-containing podoplanin receptor CLEC-2, suggesting that G6b-B inhibits CLEC-2-mediated platelet activation through Shp2. Findings from this study demonstrate that G6b-B must engage with Shp1 and Shp2 to mediate its regulatory effects on platelet homeostasis.
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