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Schlafens Can Put Viruses to Sleep. Viruses 2022; 14:v14020442. [PMID: 35216035 PMCID: PMC8875196 DOI: 10.3390/v14020442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 12/21/2022] Open
Abstract
The Schlafen gene family encodes for proteins involved in various biological tasks, including cell proliferation, differentiation, and T cell development. Schlafens were initially discovered in mice, and have been studied in the context of cancer biology, as well as their role in protecting cells during viral infection. This protein family provides antiviral barriers via direct and indirect effects on virus infection. Schlafens can inhibit the replication of viruses with both RNA and DNA genomes. In this review, we summarize the cellular functions and the emerging relationship between Schlafens and innate immunity. We also discuss the functions and distinctions of this emerging family of proteins as host restriction factors against viral infection. Further research into Schlafen protein function will provide insight into their mechanisms that contribute to intrinsic and innate host immunity.
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Heterozygous mutation SLFN14 K208N in mice mediates species-specific differences in platelet and erythroid lineage commitment. Blood Adv 2021; 5:377-390. [PMID: 33496736 DOI: 10.1182/bloodadvances.2020002404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 12/01/2020] [Indexed: 11/20/2022] Open
Abstract
Schlafen 14 (SLFN14) has recently been identified as an endoribonuclease responsible for cleaving RNA to regulate and inhibit protein synthesis. Early studies revealed that members of the SLFN family are capable of altering lineage commitment during T-cell differentiation by using cell-cycle arrest as a means of translational control by RNase activity. SLFN14 has been reported as a novel gene causing an inherited macrothrombocytopenia and bleeding in human patients; however, the role of this endoribonuclease in megakaryopoiesis and thrombopoiesis remains unknown. To investigate this, we report a CRISPR knock-in mouse model of SLFN14 K208N homologous to the K219N mutation observed in our previous patient studies. We used hematological analysis, in vitro and in vivo studies of platelet and erythrocyte function, and analysis of spleen and bone marrow progenitors. Mice homozygous for this mutation do not survive to weaning age, whereas heterozygotes exhibit microcytic erythrocytosis, hemolytic anemia, splenomegaly, and abnormal thrombus formation, as revealed by intravital microscopy, although platelet function and morphology remain unchanged. We also show that there are differences in erythroid progenitors in the spleens and bone marrow of these mice, indicative of an upregulation of erythropoiesis. This SLFN14 mutation presents distinct species-specific phenotypes, with a platelet defect reported in humans and a severe microcytic erythrocytosis in mice. Thus, we conclude that SLFN14 is a key regulator in mammalian hematopoiesis and a species-specific mediator of platelet and erythroid lineage commitment.
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Hou Y, Shao L, Zhou H, Liu Y, Fisk DG, Spiteri E, Zehnder JL, Peng J, Zhang BM, Hou M. Identification of a pathogenic TUBB1 variant in a Chinese family with congenital macrothrombocytopenia through whole genome sequencing. Platelets 2021; 32:1108-1112. [PMID: 33400601 DOI: 10.1080/09537104.2020.1869714] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Congenital macrothrombocytopenia is a genetically heterogeneous group of rare disorders. We herein report a large Chinese family presented with phenotypic variability involving thrombocytopenia and/or giant platelets. Whole genome sequencing (WGS) of the proband and one of his affected brothers identified a potentially pathogenic c.952 C > T heterozygous variant in the TUBB1 gene. This p.R318W β1-tubulin variant was also identified in three additional siblings and five members of the next generation. These findings were consistent with an autosomal dominant inheritance with incomplete penetrance. Moreover, impaired platelet agglutination in response to ristocetin was detected in the patient's brother. Half of the family members harboring the p.R318W mutation displayed significantly decreased external release of p-selectin by stimulated platelets. The p.R318W β1-tubulin mutation was identified for the first time in a Chinese family with congenital macrothrombocytopenia using WGS as an unbiased sequencing approach. Affected individuals within the family demonstrated impaired platelet aggregation and/or release functions.
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Affiliation(s)
- Yu Hou
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Shandong Provincial Key Laboratory of Immunohematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Linlin Shao
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Hai Zhou
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yanfeng Liu
- Shandong Provincial Key Laboratory of Immunohematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Dianna G Fisk
- Clinical Genomics Program, Stanford Health Care, Palo Alto, United States
| | - Elizabeth Spiteri
- Clinical Genomics Program, Stanford Health Care, Palo Alto, United States.,Department of Pathology, Stanford University School of Medicine, Palo Alto, United States
| | - James L Zehnder
- Department of Pathology, Stanford University School of Medicine, Palo Alto, United States
| | - Jun Peng
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Shandong Provincial Key Laboratory of Immunohematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Bing M Zhang
- Department of Pathology, Stanford University School of Medicine, Palo Alto, United States
| | - Ming Hou
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Shandong Provincial Key Laboratory of Immunohematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Leading Research Group of Scientific Innovation, Department of Science and Technology of Shandong Province, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
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Khan AO, Slater A, Maclachlan A, Nicolson PLR, Pike JA, Reyat JS, Yule J, Stapley R, Rayes J, Thomas SG, Morgan NV. Post-translational polymodification of β1-tubulin regulates motor protein localisation in platelet production and function. Haematologica 2020; 107:243-259. [PMID: 33327716 PMCID: PMC8719104 DOI: 10.3324/haematol.2020.270793] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Indexed: 11/17/2022] Open
Abstract
In specialized cells, the expression of specific tubulin isoforms and their subsequent post-translational modifications drive and coordinate unique morphologies and behaviors. The mechanisms by which b1-tubulin, the platelet and megakaryocyte (MK) lineage restricted tubulin isoform, drives platelet production and function remains poorly understood. We investigated the roles of two key post-translational tubulin polymodifications (polyglutamylation and polyglycylation) on these processes using a cohort of thrombocytopenic patients, human induced pluripotent stem cell derived MK, and healthy human donor platelets. We find distinct patterns of polymodification in MK and platelets, mediated by the antagonistic activities of the cell specific expression of tubulin tyrosine ligase like enzymes and cytosolic carboxypeptidase enzymes. The resulting microtubule patterning spatially regulates motor proteins to drive proplatelet formation in megakaryocytes, and the cytoskeletal reorganization required for thrombus formation. This work is the first to show a reversible system of polymodification by which different cell specific functions are achieved.
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Affiliation(s)
- Abdullah O Khan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT.
| | - Alexandre Slater
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Annabel Maclachlan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Phillip L R Nicolson
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Jeremy A Pike
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT; Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands
| | - Jasmeet S Reyat
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Jack Yule
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands
| | - Rachel Stapley
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Julie Rayes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT; Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands
| | - Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK, B15 2TT.
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