1
|
Noh JY. Megakaryopoiesis and Platelet Biology: Roles of Transcription Factors and Emerging Clinical Implications. Int J Mol Sci 2021; 22:ijms22179615. [PMID: 34502524 PMCID: PMC8431765 DOI: 10.3390/ijms22179615] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/02/2021] [Accepted: 09/02/2021] [Indexed: 12/13/2022] Open
Abstract
Platelets play a critical role in hemostasis and thrombus formation. Platelets are small, anucleate, and short-lived blood cells that are produced by the large, polyploid, and hematopoietic stem cell (HSC)-derived megakaryocytes in bone marrow. Approximately 3000 platelets are released from one megakaryocyte, and thus, it is important to understand the physiologically relevant mechanism of development of mature megakaryocytes. Many genes, including several key transcription factors, have been shown to be crucial for platelet biogenesis. Mutations in these genes can perturb megakaryopoiesis or thrombopoiesis, resulting in thrombocytopenia. Metabolic changes owing to inflammation, ageing, or diseases such as cancer, in which platelets play crucial roles in disease development, can also affect platelet biogenesis. In this review, I describe the characteristics of platelets and megakaryocytes in terms of their differentiation processes. The role of several critical transcription factors have been discussed to better understand the changes in platelet biogenesis that occur during disease or ageing.
Collapse
Affiliation(s)
- Ji-Yoon Noh
- Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea
| |
Collapse
|
2
|
Jin S, Li J, Barati M, Rane S, Lin Q, Tan Y, Zheng Z, Cai L, Rane MJ. Loss of NF-E2 expression contributes to the induction of profibrotic signaling in diabetic kidneys. Life Sci 2020; 254:117783. [DOI: 10.1016/j.lfs.2020.117783] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/02/2020] [Accepted: 05/10/2020] [Indexed: 01/14/2023]
|
3
|
Paul M, Kemparaju K, Girish KS. Inhibition of constitutive NF-κB activity induces platelet apoptosis via ER stress. Biochem Biophys Res Commun 2017; 493:1471-1477. [PMID: 28986259 DOI: 10.1016/j.bbrc.2017.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Accepted: 10/03/2017] [Indexed: 12/15/2022]
Abstract
Platelets are anucleate cells, known for their pivotal roles in hemostasis, inflammation, immunity, and disease progression. Being anuclear, platelets are known to express several transcriptional factors which exert nongenomic functions, including the positive and negative regulation of platelet activation. NF-κB is one such transcriptional factor involved in the regulation of genes for survival, proliferation, inflammation and immunity. Although, the role NF-κB in platelet activation and aggregation is partially known, its function in management of platelet survival and apoptosis remain unexplored. Therefore, two unrelated inhibitors of NF-κB activation, BAY 11-7082 and MLN4924 were used to determine the role of NF-κB in platelets. Inhibition of NF-κB caused decreased SERCA activity and increased cytosolic Ca2+ level causing ER stress which was determined by the phosphorylation of eIF2-α. Further, there was increased BAX and decreased BCl-2 levels, incidence of mitochondrial membrane potential depolarization, release of cytochrome c into cytosol, caspase activation, PS externalization and cell death in BAY 11-7082 and MLN4924 treated platelets. The obtained results demonstrate the critical role played by NF-κB in Ca2+ homeostasis and survival of platelets. In addition, the study demonstrates the potential side effects associated with NF-κB inhibitors employed during inflammation and cancer therapy.
Collapse
Affiliation(s)
- Manoj Paul
- DOS in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570 006, India
| | - Kempaiah Kemparaju
- DOS in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570 006, India.
| | - Kesturu S Girish
- DOS in Biochemistry, University of Mysore, Manasagangothri, Mysuru 570 006, India; Department of Studies and Research in Biochemistry, Tumkur University, Tumakuru 572 103, India.
| |
Collapse
|
4
|
Solier S, Fontenay M, Vainchenker W, Droin N, Solary E. Non-apoptotic functions of caspases in myeloid cell differentiation. Cell Death Differ 2017; 24:1337-1347. [PMID: 28211870 DOI: 10.1038/cdd.2017.19] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/06/2017] [Accepted: 01/16/2017] [Indexed: 12/26/2022] Open
Abstract
Subtle caspase activation is associated with the differentiation of several myeloid lineages. A tightly orchestrated dance between caspase-3 activation and the chaperone HSP70 that migrates to the nucleus to protect the master regulator GATA-1 from cleavage transiently occurs in basophilic erythroblasts and may prepare nucleus and organelle expel that occurs at the terminal phase of erythroid differentiation. A spatially restricted activation of caspase-3 occurs in maturing megakaryocytes to promote proplatelet maturation and platelet shedding in the bloodstream. In a situation of acute platelet need, caspase-3 could be activated in response to IL-1α and promote megakaryocyte rupture. In peripheral blood monocytes, colony-stimulating factor-1 provokes the formation of a molecular platform in which caspase-8 is activated, which downregulates nuclear factor-kappa B (NF-κB) activity and activates downstream caspases whose target fragments such as those generated by nucleophosmin (NPM1) cleavage contribute to the generation of resting macrophages. Human monocytes secrete mature IL-1β in response to lipopolysaccharide through an alternative inflammasome activation that involves caspase-8, a pathway that does not lead to cell death. Finally, active caspase-3 is part of the proteases contained in secretory granules of mast cells. Many questions remain on how these proteases are activated in myeloid cell lineages, which target proteins are cleaved, whereas other are protected from proteolysis, the precise role of cleaved proteins in cell differentiation and functions, and the link between these non-apoptotic functions of caspases and the death of these diverse cell types. Better understanding of these functions may generate therapeutic strategies to control cytopenias or modulate myeloid cell functions in various pathological situations.
Collapse
Affiliation(s)
- Stéphanie Solier
- Inserm U1170, Université Paris-Sud, Faculté de Médecine Paris-Sud, Gustave Roussy, Villejuif, France
| | - Michaela Fontenay
- INSERM U1016, Institut Cochin, Paris, France.,Assistance Publique-Hôpitaux de Paris, Service d'Hématologie Biologique, Hôpitaux Universitaires Paris Centre, Paris, France
| | - William Vainchenker
- Inserm U1170, Université Paris-Sud, Faculté de Médecine Paris-Sud, Gustave Roussy, Villejuif, France
| | - Nathalie Droin
- Inserm U1170, Université Paris-Sud, Faculté de Médecine Paris-Sud, Gustave Roussy, Villejuif, France
| | - Eric Solary
- Inserm U1170, Université Paris-Sud, Faculté de Médecine Paris-Sud, Gustave Roussy, Villejuif, France.,Department of Hematology, Gustave Roussy, Villejuif, France
| |
Collapse
|
5
|
Morishima N, Nakanishi K. Proplatelet formation in megakaryocytes is associated with endoplasmic reticulum stress. Genes Cells 2016; 21:798-806. [PMID: 27296088 DOI: 10.1111/gtc.12384] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 05/08/2016] [Indexed: 01/02/2023]
Abstract
Although previous studies suggest that proplatelet formation in megakaryocytes involves caspase-3, the mechanism underlying the activation of caspase-3 is unknown. Here, we analyzed caspase activation in a human megakaryoblastic cell line, MEG-01, which forms proplatelets spontaneously. Specific activation of caspase-3 and caspase-4 was found in proplatelets. Consistent with previous observations of caspase-4 autoactivation in response to endoplasmic reticulum (ER) stress, several ER stress marker proteins were expressed during proplatelet formation. A pharmacological ER stressor enhanced platelet production via proplatelet formation, whereas inhibition of caspase-4 caused suppression. These results suggest that ER stress is a mechanism underlying the maturation of megakaryocytes.
Collapse
Affiliation(s)
- Nobuhiro Morishima
- Lipid Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Keiko Nakanishi
- Lipid Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| |
Collapse
|
6
|
Gasiorek JJ, Blank V. Regulation and function of the NFE2 transcription factor in hematopoietic and non-hematopoietic cells. Cell Mol Life Sci 2015; 72:2323-35. [PMID: 25721735 PMCID: PMC11114048 DOI: 10.1007/s00018-015-1866-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/27/2015] [Accepted: 02/16/2015] [Indexed: 01/01/2023]
Abstract
The NFE2 transcription factor was identified over 25 years ago. The NFE2 protein forms heterodimers with small MAF proteins, and the resulting complex binds to regulatory elements in a large number of target genes. In contrast to other CNC transcription family members including NFE2L1 (NRF1), NFE2L2 (NRF2) and NFE2L3 (NRF3), which are widely expressed, earlier studies had suggested that the major sites of NFE2 expression are hematopoietic cells. Based on cell culture studies it was proposed that this protein acts as a critical regulator of globin gene expression. However, the knockout mouse model displayed only mild erythroid abnormalities, while the major phenotype was a defect in megakaryocyte biogenesis. Indeed, absence of NFE2 led to severely impaired platelet production. A series of recent data, also summarized here, shed new light on the various functional roles of NFE2 and the regulation of its activity. NFE2 is part of a complex regulatory network, including transcription factors such as GATA1 and RUNX1, controlling megakaryocytic and/or erythroid cell function. Surprisingly, it was recently found that NFE2 also has a role in non-hematopoietic tissues, such as the trophoblast, in which it is also expressed, as well as the bone, opening the door to new research areas for this transcription factor. Additional data showed that NFE2 function is controlled by a series of posttranslational modifications. Important strides have been made with respect to the clinical significance of NFE2, linking this transcription factor to hematological disorders such as polycythemias.
Collapse
Affiliation(s)
- Jadwiga J. Gasiorek
- Lady Davis Institute for Medical Research, McGill University, 3755 Chemin de la Côte Sainte-Catherine, Montreal, QC H3T 1E2 Canada
- Department of Medicine, McGill University, Montreal, QC Canada
| | - Volker Blank
- Lady Davis Institute for Medical Research, McGill University, 3755 Chemin de la Côte Sainte-Catherine, Montreal, QC H3T 1E2 Canada
- Department of Medicine, McGill University, Montreal, QC Canada
- Department of Physiology, McGill University, Montreal, QC Canada
| |
Collapse
|
7
|
Glembotsky AC, Bluteau D, Espasandin YR, Goette NP, Marta RF, Marin Oyarzun CP, Korin L, Lev PR, Laguens RP, Molinas FC, Raslova H, Heller PG. Mechanisms underlying platelet function defect in a pedigree with familial platelet disorder with a predisposition to acute myelogenous leukemia: potential role for candidate RUNX1 targets. J Thromb Haemost 2014; 12:761-72. [PMID: 24606315 DOI: 10.1111/jth.12550] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Indexed: 01/14/2023]
Abstract
BACKGROUND Familial platelet disorder with a predisposition to acute myelogenous leukemia (FPD/AML) is an inherited platelet disorder caused by a germline RUNX1 mutation and characterized by thrombocytopenia, a platelet function defect, and leukemia predisposition. The mechanisms underlying FPD/AML platelet dysfunction remain incompletely clarified. We aimed to determine the contribution of platelet structural abnormalities and defective activation pathways to the platelet phenotype. In addition, by using a candidate gene approach, we sought to identify potential RUNX1-regulated genes involved in these defects. METHODS Lumiaggregometry, α-granule and dense granule content and release, platelet ultrastructure, αIIb β3 integrin activation and outside-in signaling were assessed in members of one FPD/AML pedigree. Expression levels of candidate genes were measured and luciferase reporter assays and chromatin immunoprecipitation were performed to study NF-E2 regulation by RUNX1. RESULTS A severe decrease in platelet aggregation, defective αIIb β3 integrin activation and combined αδ storage pool deficiency were found. However, whereas the number of dense granules was markedly reduced, α-granule content was heterogeneous. A trend towards decreased platelet spreading was found, and β3 integrin phosphorylation was impaired, reflecting altered outside-in signaling. A decrease in the level of transcription factor p45 NF-E2 was shown in platelet RNA and lysates, and other deregulated genes included RAB27B and MYL9. RUNX1 was shown to bind to the NF-E2 promoter in primary megakaryocytes, and wild-type RUNX1, but not FPD/AML mutants, was able to activate NF-E2 expression. CONCLUSIONS The FPD/AML platelet function defect represents a complex trait, and RUNX1 orchestrates platelet function by regulating diverse aspects of this process. This study highlights the RUNX1 target NF-E2 as part of the molecular network by which RUNX1 regulates platelet biogenesis and function.
Collapse
Affiliation(s)
- A C Glembotsky
- Departamento de Hematología Investigación, Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Tijssen MR, Ghevaert C. Transcription factors in late megakaryopoiesis and related platelet disorders. J Thromb Haemost 2013; 11:593-604. [PMID: 23311859 PMCID: PMC3824237 DOI: 10.1111/jth.12131] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2013] [Indexed: 01/09/2023]
Abstract
Cell type-specific transcription factors regulate the repertoire of genes expressed in a cell and thereby determine its phenotype. The differentiation of megakaryocytes, the platelet progenitors, from hematopoietic stem cells is a well-known process that can be mimicked in culture. However, the efficient formation of platelets in culture remains a challenge. Platelet formation is a complicated process including megakaryocyte maturation, platelet assembly and platelet shedding. We hypothesize that a better understanding of the transcriptional regulation of this process will allow us to influence it such that sufficient numbers of platelets can be produced for clinical applications. After an introduction to gene regulation and platelet formation, this review summarizes the current knowledge of the regulation of platelet formation by the transcription factors EVI1, GATA1, FLI1, NFE2, RUNX1, SRF and its co-factor MKL1, and TAL1. Also covered is how some platelet disorders including myeloproliferative neoplasms, result from disturbances of the transcriptional regulation. These disorders give us invaluable insights into the crucial role these transcription factors play in platelet formation. Finally, there is discussion of how a better understanding of these processes will be needed to allow for efficient production of platelets in vitro.
Collapse
Affiliation(s)
- M R Tijssen
- Department of Haematology, University of CambridgeUK
- Department of Haematology, University of Cambridge, and NHS Blood and TransplantCambridge, UK
| | - C Ghevaert
- Department of Haematology, University of Cambridge, and NHS Blood and TransplantCambridge, UK
| |
Collapse
|
9
|
Matsubara Y, Ono Y, Suzuki H, Arai F, Suda T, Murata M, Ikeda Y. OP9 bone marrow stroma cells differentiate into megakaryocytes and platelets. PLoS One 2013; 8:e58123. [PMID: 23469264 PMCID: PMC3585802 DOI: 10.1371/journal.pone.0058123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 01/31/2013] [Indexed: 01/04/2023] Open
Abstract
Platelets are essential for hemostatic plug formation and thrombosis. The mechanisms of megakaryocyte (MK) differentiation and subsequent platelet production from stem cells remain only partially understood. The manufacture of megakaryocytes (MKs) and platelets from cell sources including hematopoietic stem cells and pluripotent stem cells have been highlighted for studying the platelet production mechanisms as well as for the development of new strategies for platelet transfusion. The mouse bone marrow stroma cell line OP9 has been widely used as feeder cells for the differentiation of stem cells into MK lineages. OP9 cells are reported to be pre-adipocytes. We previously reported that 3T3-L1 pre-adipocytes differentiated into MKs and platelets. In the present study, we examined whether OP9 cells differentiate into MKs and platelets using MK lineage induction (MKLI) medium previously established to generate MKs and platelets from hematopoietic stem cells, embryonic stem cells, and pre-adipocytes. OP9 cells cultured in MKLI medium had megakaryocytic features, i.e., positivity for surface markers CD41 and CD42b, polyploidy, and distinct morphology. The OP9-derived platelets had functional characteristics, providing the first evidence for the differentiation of OP9 cells into MKs and platelets. We then analyzed gene expressions of critical factors that regulate megakaryopoiesis and thrombopoiesis. The gene expressions of p45NF-E2, FOG, Fli1, GATA2, RUNX1, thrombopoietin, and c-mpl were observed during the MK differentiation. Among the observed transcription factors of MK lineages, p45NF-E2 expression was increased during differentiation. We further studied MK and platelet generation using p45NF-E2-overexpressing OP9 cells. OP9 cells transfected with p45NF-E2 had enhanced production of MKs and platelets. Our findings revealed that OP9 cells differentiated into MKs and platelets in vitro. OP9 cells have critical factors for megakaryopoiesis and thrombopoiesis, which might be involved in a mechanism of this differentiation. p45NF-E2 might also play important roles in the differentiation of OP9 cells into MK lineages cells.
Collapse
Affiliation(s)
- Yumiko Matsubara
- Department of Laboratory Medicine, Keio University School of Medicine, Tokyo, Japan.
| | | | | | | | | | | | | |
Collapse
|
10
|
Abstract
Determinant factors leading from stem cells to megakaryocytes (MKs) and subsequently platelets have yet to be identified. We now report that a combination of nuclear factor erythroid-derived 2 p45 unit (p45NF-E2), Maf G, and Maf K can convert mouse fibroblast 3T3 cells and adult human dermal fibroblasts into MKs. To screen MK-inducing factors, gene expressions were compared between 3T3 cells that do not differentiate into MKs and 3T3-L1 cells known to differentiate into MKs. 3T3 cells transfected with candidate factors were cultured in a defined MK lineage induction medium. Among the tested factors, transfection with p45NF-E2/MafG/MafK lead to the highest frequency of CD41-positive cells. Adult human dermal fibroblasts transfected with these genes were cultured in MK lineage induction medium. Cultured cells had megakaryocytic features, including surface markers, ploidy, and morphology. More than 90% of MK-sized cells expressed CD41, designated induced MK (iMK). Infusion of these iMK cells into immunodeficient mice led to a time-dependent appearance of CD41-positive, platelet-sized particles. Blood samples from iMK-infused into thrombocytopenic immunodeficient mice were perfused on a collagen-coated chip, and human CD41-positive platelets were incorporated into thrombi on the chip, demonstrating their functionality. These findings demonstrate that a combination of p45NF-E2, Maf G, and Maf K is a key determinant of both megakaryopoiesis and thrombopoiesis.
Collapse
|
11
|
Matsubara Y, Murata M, Ikeda Y. Culture of megakaryocytes and platelets from subcutaneous adipose tissue and a preadipocyte cell line. Methods Mol Biol 2012; 788:249-258. [PMID: 22130712 DOI: 10.1007/978-1-61779-307-3_17] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The molecular mechanisms whereby stem cells develop into platelet-producing megakaryocytes (MKs) are not yet fully understood. Within this chapter we describe a two-step in vitro culture system in which MKs and platelets are generated from primary subcutaneous adipose tissues and the preadipocyte cell line 3T3L1. The cells are first cultured in an adipocyte induction medium for 10-12 days, followed by 8-14 days culture in a MK differentiation medium. Adipose tissue-derived MKs and platelets display a number of morphological and functional characteristics (e.g., secretory granules, open canalicular membranes) comparable with the native cell type. The use of subcutaneous adipose tissue to produce a large number of platelets is advantageous because this tissue is easily obtained and available in large quantities. Thus, this in vitro culture system may prove useful in both regenerative medicine, but it may also be used in understanding fundamental research questions within MK and platelet research, including further elucidation of the pathways that cause cells to differentiate along the MK lineage ultimately leading to platelet production.
Collapse
Affiliation(s)
- Yumiko Matsubara
- Department of Laboratory Medicine, School of Medicine, Keio University, Tokyo, Japan.
| | | | | |
Collapse
|
12
|
Ono M, Matsubara Y, Shibano T, Ikeda Y, Murata M. GSK-3β negatively regulates megakaryocyte differentiation and platelet production from primary human bone marrow cells in vitro. Platelets 2011; 22:196-203. [PMID: 21231855 DOI: 10.3109/09537104.2010.541959] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Glycogen synthase kinase (GSK)-3, a constitutively active serine-threonine kinase, acts as a key regulator of major signaling pathways, including the Wnt, Hedgehog, and Notch pathways. Although a number of studies have demonstrated that GSK-3 plays a critical role in several cellular processes, such as differentiation, growth, and apoptosis, the effects of GSK-3 on platelet production have not been explored. There are two GSK-3 isoforms, GSK-3α and GSK-3β. GSK-3β is more highly expressed in platelets. In the present study, primary human bone marrow cells were cultured for 12 days in megakaryocyte lineage induction (MKLI) media to induce their differentiation into megakaryocyte (MK) lineage cells, in the presence or absence (+/-) of TWS119, a GSK-3β inhibitor, during MK differentiation from stem cells and subsequent platelet production. MK maturation, MK production, and subsequent platelet production were markedly enhanced in cells cultured in TWS119 (+) compared with cells cultured in TWS119 (-). These effects on MK lineage cells were thrombopoietin (TPO)-dependent. We next performed the experiment focusing on the inhibitory effect of GSK-3β on platelet production. Bone marrow cell-derived CD41 (+)/CD42b (+)/propidium iodide (-) cells in the large (MK)-sized cell population (day 8), as living mature MKs, were further cultured in the MKLI media in TWS119 (+/-) for 6 days. Platelet production from mature MKs in TWS119 (+) was approximately two-fold higher than that in TWS119 (-). The mature MKs were cultured in MKLI media in TWS119, in TPO (+/-), and platelet production was markedly decreased in TPO (-). This indicated that the GSK-3β inhibition affects thrombopoiesis under these conditions with TPO. To identify the target(s) of GSK-3β inhibition during differentiation into MK lineage cells, we performed a differential gene expression study and subsequent pathway analysis of the large (MK)-sized CD41 (+)/propidium iodide (-) cells cultured in TWS119 (+/-) for 3 days. The results of the analysis indicated that GSK-3β inhibition during differentiation into MK lineage cells affected factors related to transcription, apoptosis, cell division, cell cycle, blood coagulation, lipid transport, keratin filament, metabolic processes, and the Wnt signaling and transforming growth factor-β signaling pathways. These observations suggest that GSK-3β inhibition and TPO treatment affect both megakaryopoiesis and thrombopoiesis in an in vitro differentiation system for primary human bone marrow cells.
Collapse
Affiliation(s)
- Mayumi Ono
- The Keio-Daiichi Sankyo Project on Genetics of Thrombosis, Keio University School of Medicine, Tokyo, Japan
| | | | | | | | | |
Collapse
|
13
|
Perdomo J, Fock EL, Kaur G, Yan F, Khachigian LM, Jans DA, Chong BH. A monopartite sequence is essential for p45 NF-E2 nuclear translocation, transcriptional activity and platelet production. J Thromb Haemost 2010; 8:2542-53. [PMID: 20854373 DOI: 10.1111/j.1538-7836.2010.04058.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND p45 NF-E2 is a bZIP transcription factor crucial for thrombopoiesis, as indicated by the fact that loss of p45 NF-E2 function results in dramatic embryonic lethal thrombopoietic defects and its overexpression boosts platelet release. OBJECTIVES In the present study, we set out to identify the sequences responsible for p45 NF-E2 nuclear import, evaluate its transport mechanism and ascertain its functional significance. METHODS A series of p45 NF-E2 deletion constructs fused to green fluorescent protein (GFP) was created and their cellular localization examined in mammalian cells, with the factor responsible for nuclear import identified using an in vitro transport assay. A p45 NF-E2 derivative mutated in the nuclear targeting sequence (NLS) was generated and its biological activity compared with wild type (wt) in luciferase assays, and proplatelet and platelet production measured in murine megakaryocytes transduced with a retroviral vector. RESULTS Here we show that residues 271-273 are essential for nuclear import of p45 NF-E2 in COS-7 and in primary bone marrow cells. The p45 NF-E2 NLS facilitates nuclear import specifically via importin (IMP) 7. Although within the DNA-binding domain of p45 NF-E2, the NLS is not essential for DNA-binding, but is crucial for transcriptional activation and biological activity; where, in contrast to wt, a mutant derivative with a mutated NLS failed to promote proplatelet and platelet production in murine megakaryocytes. CONCLUSIONS The NLS is critical for p45 NF-E2 function, with the present study being the first to demonstrate the importance of NLS-dependent nuclear import of p45 NF-E2 for platelet development.
Collapse
Affiliation(s)
- J Perdomo
- Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia
| | | | | | | | | | | | | |
Collapse
|
14
|
Matsubara Y, Suzuki H, Ikeda Y, Murata M. Generation of megakaryocytes and platelets from preadipocyte cell line 3T3-L1, but not the parent cell line 3T3, in vitro. Biochem Biophys Res Commun 2010; 402:796-800. [PMID: 21040704 DOI: 10.1016/j.bbrc.2010.10.120] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 10/26/2010] [Indexed: 10/18/2022]
Abstract
Platelets are produced from megakaryocytes (MKs), although the pathway leading from stem cells to MK lineages are not yet fully understood. Recently, we reported to obtain abundant MKs and platelets from human subcutaneous adipose tissues. Adipose tissues contain various cell types, most of which are lineage cells from mesenchymal or adipocyte-derived stem cells, distinct from hematopoietic cells. To identify the cells responsible for the differentiation MK lineages in adipose tissues, this study examined whether the preadipocyte cell line 3T3-L1 and fibroblast cell line 3T3 differentiated into MK lineages in vitro. Cells were cultured in megakaryocyte lineage induction medium. By day 4, most of 3T3 cell-derived cells leaded to cell death. In contrast, 3T3-L1-derived cells on days 8 showed to have typical characterizations of MK lineages in analyses for specific marker, DNA ploidy, transmission electro micrograph. 3T3-L1-derived platelet-sized cells on day 12 could be stimulated by ADP and PAR4-activating peptide. This study clearly shows in vitro differentiation from 3T3-L1 cells, not from 3T3 cells, into MK lineages.
Collapse
Affiliation(s)
- Yumiko Matsubara
- Department of Laboratory Medicine, School of Medicine, Keio University, Tokyo, Japan.
| | | | | | | |
Collapse
|
15
|
Kleiman NS, Freedman JE, Tracy PB, Furie BC, Bray PF, Rao SV, Phillips DR, Storey RF, Rusconi CP, French PA, Steinhubl SR, Becker RC. Platelets: Developmental biology, physiology, and translatable platforms for preclinical investigation and drug development. Platelets 2009; 19:239-51. [DOI: 10.1080/09537100801947442] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
16
|
López JJ, Redondo PC, Salido GM, Pariente JA, Rosado JA. N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine induces apoptosis through the activation of caspases-3 and -8 in human platelets. A role for endoplasmic reticulum stress. J Thromb Haemost 2009; 7:992-9. [PMID: 19548908 DOI: 10.1111/j.1538-7836.2009.03431.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Apoptosis or programmed cell death involves a number of biochemical events, including the activation of caspases, which lead to specific cell morphology changes and ultimately cell death. Traditionally, two apoptotic pathways have been described: the cell-surface death receptor-dependent extrinsic pathway and the mitochondria-dependent intrinsic pathway. Alternatively, apoptosis has been reported to be induced by endoplasmic reticulum (ER) stress, which is mainly induced by a reduction in intraluminal free Ca(2+) concentration ([Ca(2+)](ER)). OBJECTIVES The present study aimed to investigate the development of apoptotic events after ER stress induced by N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), an ER Ca(2+) chelator, in human platelets. METHODS Changes in cytosolic free Ca(2+) concentration, caspase activity and phosphatidylserine externalization were determined by fluorimetric techniques. RESULTS Our results indicate that TPEN reduces the amount of free Ca(2+) releasable by the Ca(2+)-mobilizing agonist thrombin. TPEN induced activation of caspase-3, -8 and -9 and subsequent phosphatidylserine externalization. The ability of TPEN to induce phosphatidylserine externalization was smaller than that of thrombin. In addition, TPEN was able to induce phosphorylation of the eukaryotic initiation factor 2 alpha (eIF2 alpha). TPEN-mediated caspase-3 activation requires functional caspase-8, but is independent of H(2)O(2) generation. Activation of caspase-3 and -8 by TPEN was prevented by salubrinal, an agent that prevents ER stress-induced apoptosis. CONCLUSION These findings provide experimental evidence for the existence of ER stress-mediated apoptosis in human platelets, a process that might limit platelet life span upon prolonged stimulation with agonists.
Collapse
Affiliation(s)
- J J López
- Department of Physiology, University of Extremadura, Cáceres, Spain
| | | | | | | | | |
Collapse
|
17
|
Matsubara Y, Saito E, Suzuki H, Watanabe N, Murata M, Ikeda Y. Generation of megakaryocytes and platelets from human subcutaneous adipose tissues. Biochem Biophys Res Commun 2009; 378:716-20. [DOI: 10.1016/j.bbrc.2008.11.117] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 11/19/2008] [Indexed: 12/21/2022]
|
18
|
Fock EL, Yan F, Pan S, Chong BH. NF-E2-mediated enhancement of megakaryocytic differentiation and platelet production in vitro and in vivo. Exp Hematol 2007; 36:78-92. [PMID: 17923245 DOI: 10.1016/j.exphem.2007.08.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 08/07/2007] [Accepted: 08/09/2007] [Indexed: 12/31/2022]
Abstract
OBJECTIVE NF-E2 is a prime regulator of megakaryocyte (MK) terminal differentiation and platelet release. By overexpressing the p45 subunit of NF-E2, we aim to increase the proportion of mature MKs and the potential for platelet production in vitro and in vivo. METHODS Retroviral vectors expressing p45-NF-E2 together with the enhanced green fluorescent protein (eGFP) were used to transduce murine bone marrow cells (BMCs). Aspects of MK differentiation, proliferation, proplatelet, and platelet production were evaluated. RESULTS Compared to controls, a higher proportion of BMCs overexpressing p45-NF-E2 were found to express the MK markers CD41, CD42a, and CD42b, with some effect on cell proliferation. Early MK differentiation, characterized by colony-forming unit (CFU)-MK formation, was enhanced by p45-NF-E2 overexpression at the expense of CFU-granulocyte macrophage development. An increased number of acetylcholinesterase(+) MKs was also observed in NF-E2(++) cultures. Although endomitosis was found not to be affected, the resultant upregulation of NF-E2 target genes was also followed by significant increases in proplatelet and functional platelet production. Transplantation of enriched MK progenitor cells overexpressing p45-NF-E2 into lethally irradiated mice resulted in a threefold increase in eGFP(+)/NF-E2(++) platelet production in vivo over 10 days, although no appreciable expansion in their number was observed over 32 days. CONCLUSION These results suggest that enforced expression of p45-NF-E2 selectively enhances many aspects of MK differentiation, including MK maturation, proplatelet formation, and platelet release. In addition, p45 overexpression increases MK commitment during early megakaryopoiesis, while inhibiting white blood cell differentiation.
Collapse
Affiliation(s)
- Ee-ling Fock
- Centre for Vascular Research, Department of Medicine, St. George Clinical School, University of New South Wales, Sydney, Australia
| | | | | | | |
Collapse
|
19
|
Chen Z, Hu M, Shivdasani RA. Expression analysis of primary mouse megakaryocyte differentiation and its application in identifying stage-specific molecular markers and a novel transcriptional target of NF-E2. Blood 2007; 109:1451-9. [PMID: 17047147 PMCID: PMC1794061 DOI: 10.1182/blood-2006-08-038901] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 09/25/2006] [Indexed: 12/22/2022] Open
Abstract
Megakaryocyte (MK) differentiation is well described in morphologic terms but its molecular counterparts and the basis for platelet release are incompletely understood. We profiled mRNA expression in populations of primary mouse MKs representing successive differentiation stages. Genes associated with DNA replication are highly expressed in young MKs, in parallel with endomitosis. Intermediate stages are characterized by disproportionate expression of genes associated with the cytoskeleton, cell migration, and G-protein signaling, whereas terminally mature MKs accumulate hemostatic factors, including many membrane proteins. We used these expression profiles to extract a reliable panel of molecular markers for MKs of early, intermediate, or advanced differentiation and establish the value of this marker panel using mouse models of defective thrombopoiesis resulting from absence of GATA1, NF-E2, or tubulin beta1. Computational analysis of the promoters of late-expressed MK genes identified new candidate targets for NF-E2, a critical transcriptional regulator of platelet release. One such gene encodes the kinase adaptor protein LIMS1/PINCH1, which is highly expressed in MKs and platelets and significantly reduced in NF-E2-deficient cells. Transactivation studies and chromatin immunoprecipitation implicate Lims1 as a direct target of NF-E2 regulation. Attribution of stage-specific genes, in combination with various applications, thus constitutes a powerful way to study MK differentiation and platelet biogenesis.
Collapse
Affiliation(s)
- Zhao Chen
- Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Brigham & Women's Hospital, Boston, MA 02115, USA
| | | | | |
Collapse
|
20
|
Liu J, DeNofrio J, Yuan W, Wang Z, McFadden AW, Parise LV. Genetic Manipulation of Megakaryocytes to Study Platelet Function. Curr Top Dev Biol 2007; 80:311-35. [DOI: 10.1016/s0070-2153(07)80008-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
|
21
|
|
22
|
McCormack MP, Hall MA, Schoenwaelder SM, Zhao Q, Ellis S, Prentice JA, Clarke AJ, Slater NJ, Salmon JM, Jackson SP, Jane SM, Curtis DJ. A critical role for the transcription factor Scl in platelet production during stress thrombopoiesis. Blood 2006; 108:2248-56. [PMID: 16763211 PMCID: PMC1895552 DOI: 10.1182/blood-2006-02-002188] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Accepted: 05/30/2006] [Indexed: 12/12/2022] Open
Abstract
The generation of platelets from megakaryocytes in the steady state is regulated by a variety of cytokines and transcription factors, including thrombopoietin (TPO), GATA-1, and NF-E2. Less is known about platelet production in the setting of stress thrombopoiesis, a pivotal event in the context of cytotoxic chemotherapy. Here we show in mice that the transcription factor Scl is critical for platelet production after chemotherapy and in thrombopoiesis induced by administration of TPO. Megakaryocytes from these mice showed appropriate increases in number and ploidy but failed to shed platelets. Ultrastructural examination of Scl-null megakaryocytes revealed a disorganized demarcation membrane and reduction in platelet granules. Quantitative real-time polymerase chain reaction showed that Scl-null platelets lacked NF-E2, and chromatin immunoprecipitation analysis demonstrated Scl binding to the NF-E2 promoter in the human megakaryoblastic-cell line Meg-01, along with its binding partners E47, Lmo2, and the cofactors Ldb1 and GATA-2. These findings suggest that Scl acts up-stream of NF-E2 expression to control megakaryocyte development and platelet release in settings of thrombopoietic stress.
Collapse
Affiliation(s)
- Matthew P McCormack
- Bone Marrow Research Laboratories, Royal Melbourne Hospital, Melbourne Health Research Directorate, c/o Royal Melbourne Hospital Post Office, Grattan St, Parkville VIC 3050 Australia
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Nurden P, Debili N, Vainchenker W, Bobe R, Bredoux R, Corvazier E, Combrie R, Fressinaud E, Meyer D, Nurden AT, Enouf J. Impaired megakaryocytopoiesis in type 2B von Willebrand disease with severe thrombocytopenia. Blood 2006; 108:2587-95. [PMID: 16720832 DOI: 10.1182/blood-2006-03-009449] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In type 2B von Willebrand disease, there is spontaneous binding of mutated von Willebrand factor (VWF) multimers to platelets. Here we report a family in which severe thrombocytopenia may also be linked to abnormal megakaryocytopoiesis. A heterozygous mutation in the VWF A1 domain gave a R1308P substitution in an interactive site for glycoprotein Ibalpha (GPIbalpha). Electron microscopy showed clusters of platelets in close contact. Binding of antibodies to the GPIbalpha N-terminal domain was decreased, whereas GPIX and GPV were normally detected. In Western blotting (WB), GPIbalpha, alphaIIb, and beta3 were normally present. Proteins involved in Ca(2+) homeostasis were analyzed by quantitating platelet mRNA or by WB. Plasma membrane Ca(2+) ATPase (PMCA)-4b and type III inositol trisphosphate receptor (InsP(3)-R3) were selectively increased. The presence of degradation products of polyadenosine diphosphate (ADP)-ribose polymerase protein (PARP) suggested ongoing caspase-3 activity. These were findings typical of immature normal megakaryocytes cultured from peripheral blood CD34(+) cells with TPO. Significantly, megakaryocytes from the patients in culture produced self-associated and interwoven proplatelets. Immunolocalization showed VWF not only associated with platelets, but already on the megakaryocyte surface and within internal channels. In this family, type 2B VWD is clearly associated with abnormal platelet production.
Collapse
Affiliation(s)
- Paquita Nurden
- Centre de Référence des Pathologies Plaquettaires and Institut Fédératif de Recherche No. 4, Laboratoire d'Hématologie, Hôpital Cardiologique, 33604 Pessac, France.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Larson MK, Watson SP. Regulation of proplatelet formation and platelet release by integrin alpha IIb beta3. Blood 2006; 108:1509-14. [PMID: 16670270 DOI: 10.1182/blood-2005-11-011957] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mature megakaryocytes form structures called proplatelets that serve as conduits for platelet packaging and release at vascular sinusoids. Since the megakaryocyte expresses abundant levels of integrin alpha IIb beta3, we have examined a role for fibrinogen in proplatelet development and platelet release alongside that of other matrices. Primary mature murine megakaryocytes from bone marrow aspirates readily formed proplatelets when plated on fibrinogen at a degree that was significantly higher than that seen on other matrices. In addition, alpha IIb beta3 was essential for proplatelet formation on fibrinogen, as megakaryocytes failed to develop proplatelets in the presence of alpha IIb beta3 antagonists. Interestingly, inhibition of Src kinases or Ca2+ release did not inhibit proplatelet formation, indicating that alpha IIb beta3-mediated outside-in signals are not required for this response. Immunohistochemical studies demonstrated that fibrinogen is localized to the bone marrow sinusoids, a location that would allow it to readily influence platelet release. Further, thrombopoietin-stimulated alpha IIb-/- mice had a reduced increase in platelet number relative to controls. A similar observation was not observed for platelet recovery in alpha IIb-/- mice in response to antibody-induced thrombocytopenia, indicating the existence of additional pathways of regulation of proplatelet formation. These results demonstrate that fibrinogen is able to regulate proplatelet formation via integrin alpha IIb beta3.
Collapse
Affiliation(s)
- Mark K Larson
- Centre for Cardiovascular Sciences, Institute for Biomedical Research, University of Birmingham, United Kingdom.
| | | |
Collapse
|
25
|
Patel SR, Hartwig JH, Italiano JE. The biogenesis of platelets from megakaryocyte proplatelets. J Clin Invest 2006; 115:3348-54. [PMID: 16322779 PMCID: PMC1297261 DOI: 10.1172/jci26891] [Citation(s) in RCA: 363] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Platelets are formed and released into the bloodstream by precursor cells called megakaryocytes that reside within the bone marrow. The production of platelets by megakaryocytes requires an intricate series of remodeling events that result in the release of thousands of platelets from a single megakaryocyte. Abnormalities in this process can result in clinically significant disorders. Thrombocytopenia (platelet counts less than 150,000/microl) can lead to inadequate clot formation and increased risk of bleeding, while thrombocythemia (platelet counts greater than 600,000/microl) can heighten the risk for thrombotic events, including stroke, peripheral ischemia, and myocardial infarction. This Review will describe the process of platelet assembly in detail and discuss several disorders that affect platelet production.
Collapse
Affiliation(s)
- Sunita R Patel
- Hematology Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
| | | | | |
Collapse
|
26
|
Gaur M, Kamata T, Wang S, Moran B, Shattil SJ, Leavitt AD. Megakaryocytes derived from human embryonic stem cells: a genetically tractable system to study megakaryocytopoiesis and integrin function. J Thromb Haemost 2006; 4:436-42. [PMID: 16420577 DOI: 10.1111/j.1538-7836.2006.01744.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND The platelet fibrinogen receptor, a heterodimer consisting of integrin subunits alpha(IIb) and beta(3), is required for platelet aggregation, spreading, and hemostasis. Platelet agonists such as thrombin and adenosine diphosphate (ADP) lead to the activation of alpha(IIb)beta(3), thereby enhancing its affinity and avidity for binding fibrinogen (inside-out signaling). Furthermore, fibrinogen binding to alpha(IIb)beta(3) triggers cytoskeletal changes and granule release (outside-in signaling). AIM Genetic approaches to characterize the molecular pathways involved in alpha(IIb)beta(3) signaling are not possible with anucleate blood platelets. Therefore, we have established an OP9 stromal cell co-culture system to generate megakaryocytes from human embryonic stem cells (hESCs). RESULTS alpha(IIb)beta(3) activation, measured by soluble fibrinogen binding to hESC-derived megakaryocytes, /GPIbalpha(+) cells, is readily detectable following stimulation with known platelet agonists. Dose-response curves for peptide agonists specific for the two platelet thrombin receptors, protease-activated receptor 1 (PAR1) and PAR4, show a relative responsiveness that mirrors that of human platelets, and sub-maximal ADP responses are augmented by epinephrine. Moreover, hESC-derived megakaryocytes undergo lamellipodia formation, actin filament assembly, and vinculin localization at focal adhesions when plated on a fibrinogen-coated surface, characteristic of alpha(IIb)beta(3) outside-in signaling. Undifferentiated hESCs genetically modified by lentiviral infection can be cloned and maintained in an undifferentiated state and then differentiated into megakaryocytes capable of alpha(IIb)beta(3) activation. CONCLUSION Using hESCs, we have developed a renewable source of human megakaryocytes, and a genetically tractable system for studying megakaryocytopoiesis and alpha(IIb)beta(3) signaling in the native cellular environment.
Collapse
Affiliation(s)
- M Gaur
- Department of Laboratory Medicine, University of California, San Francisco, CA 94142, USA
| | | | | | | | | | | |
Collapse
|
27
|
Rosado JA, Lopez JJ, Gomez-Arteta E, Redondo PC, Salido GM, Pariente JA. Early caspase-3 activation independent of apoptosis is required for cellular function. J Cell Physiol 2006; 209:142-52. [PMID: 16791842 DOI: 10.1002/jcp.20715] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A number of pro-apoptotic stimuli induce the activation of caspase-9, an initiator protease that activates executioner caspases, such as caspase-3, leading to the development of programmed cell death. Here we demonstrate that cell (platelets and pancreatic acinar cells) stimulation with agonists induces a bimodal activation of caspase-3. The early caspase-3 activation occurs within 1 min of stimulation and is independent on caspase-9 or mitochondrial cytochrome c release suggesting that is a non-apoptotic event. The ability of agonists to induce early activation of caspase-3 is similar to that observed for other physiological processes. Activation of caspase-3 by physiological concentrations of cellular agonists, including thrombin or CCK-8, is independent of rises in cytosolic calcium concentration but requires PKC activation, and is necessary for agonist-induced activation of the tyrosine kinases Btk and pp60src and for several cellular functions, including store-operated calcium entry, platelet aggregation, or pancreatic secretion. Thus, early activation of caspase-3 seems to be a non-apoptotic event required for cellular function.
Collapse
Affiliation(s)
- Juan A Rosado
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, Cáceres, Spain.
| | | | | | | | | | | |
Collapse
|
28
|
Muntean AG, Crispino JD. Differential requirements for the activation domain and FOG-interaction surface of GATA-1 in megakaryocyte gene expression and development. Blood 2005; 106:1223-31. [PMID: 15860665 PMCID: PMC1895209 DOI: 10.1182/blood-2005-02-0551] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Accepted: 04/12/2005] [Indexed: 11/20/2022] Open
Abstract
GATA1 is mutated in patients with 2 different disorders. First, individuals with a GATA1 mutation that blocks the interaction between GATA-1 and its cofactor Friend of GATA-1 (FOG-1) suffer from dyserythropoietic anemia and thrombocytopenia. Second, children with Down syndrome who develop acute megakaryoblastic leukemia harbor mutations in GATA1 that lead to the exclusive expression of a shorter isoform named GATA-1s. To determine the effect of these patient-specific mutations on GATA-1 function, we first compared the gene expression profile between wild-type and GATA-1-deficient megakaryocytes. Next, we introduced either GATA-1s or a FOG-binding mutant (V205G) into GATA-1-deficient megakaryocytes and assessed the effect on differentiation and gene expression. Whereas GATA-1-deficient megakaryocytes failed to undergo terminal differentiation and proliferated excessively in vitro, GATA-1s-expressing cells displayed proplatelet formation and other features of terminal maturation, but continued to proliferate aberrantly. In contrast, megakaryocytes that expressed V205G GATA-1 exhibited reduced proliferation, but failed to undergo maturation. Examination of the expression of megakaryocyte-specific genes in the various rescued cells correlated with the observed phenotypic differences. These studies show that GATA-1 is required for both normal regulation of proliferation and terminal maturation of megakaryocytes, and further, that these functions can be uncoupled by mutations in GATA1.
Collapse
Affiliation(s)
- Andrew G Muntean
- Ben May Institute for Cancer Research, Univeristy of Chicago, IL, USA
| | | |
Collapse
|
29
|
Wee JL, Jackson DE. The Ig-ITIM superfamily member PECAM-1 regulates the "outside-in" signaling properties of integrin alpha(IIb)beta3 in platelets. Blood 2005; 106:3816-23. [PMID: 16081692 DOI: 10.1182/blood-2005-03-0911] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Previous studies have implicated the immunoglobulin (Ig)-immunoreceptor tyrosine-based inhibitory motif (ITIM) superfamily member platelet endothelial cell adhesion molecule-1 (PECAM-1) in the regulation of integrin function. While PECAM-1 has been demonstrated to play a role as an inhibitory coreceptor of immunoreceptor tyrosine-based activation motif (ITAM)-associated Fcgamma receptor IIa (FcgammaRIIa) and glycoprotein VI (GPVI)/FcR gamma-chain signaling pathways in platelets, its physiologic role in integrin alpha(IIb)beta3-mediated platelet function is unclear. In this study, we investigate the functional importance of PECAM-1 in murine platelets. Using PECAM-1-deficient mice, we show that the platelets have impaired "outside-in" integrin alpha(IIb)beta3 signaling with impaired platelet spreading on fibrinogen, failure to retract fibrin clots in vitro, and reduced tyrosine phosphorylation of focal adhesion kinase p125 (125FAK) following integrin alpha(IIb)beta3-mediated platelet aggregation. This functional integrin alpha(IIb)beta3 defect could not be attributed to altered expression of integrin alpha(IIb)beta3. PECAM-1-/- platelets displayed normal platelet alpha granule secretion, normal platelet aggregation to protease-activated receptor-4 (PAR-4), adenosine diphosphate (ADP), and calcium ionophore, and static platelet adhesion. In addition, PECAM-1-/- platelets displayed normal "inside-out" integrin alpha(IIb)beta3 signaling properties as demonstrated by normal agonist-induced binding of soluble fluoroscein isothiocyanate (FITC)-fibrinogen, JON/A antibody binding, and increases in cytosolic-free calcium and inositol (1,4,5)P3 triphosphate (IP3) levels. This study provides direct evidence that PECAM-1 is essential for normal integrin alpha(IIb)beta3-mediated platelet function and that disruption of PECAM-1 induced a moderate "outsidein" integrin alpha(IIb)beta3 signaling defect.
Collapse
Affiliation(s)
- Janet L Wee
- Kronheimer Building, Austin Research Institute, Austin Health, Studley Road, Heidelberg, Victoria 3084, Australia
| | | |
Collapse
|
30
|
Abstract
Megakaryocytes (MKs) expand and differentiate over several days in response to thrombopoietin (Tpo) before releasing innumerable blood platelets. The final steps in platelet assembly and release represent a unique cellular transformation that is orchestrated by a range of transcription factors, signaling molecules, and cytoskeletal elements. Here we review recent advances in the physiology and molecular basis of MK differentiation. Genome-wide approaches, including transcriptional profiling and proteomics, have been used to identify novel platelet products and differentiation markers. The extracellular factors, stromal-derived factor (SDF)-1 chemokine and fibroblast growth factor (FGF)-4 direct MK interactions with the bone marrow stroma and regulate cytokine-independent cell maturation. An abundance of bone marrow MKs induce pathologic states, including excessive bone formation and myelofibrosis, and the basis for these effects is now better appreciated. We review the status of transcription factors that control MK differentiation, with special emphasis on nuclear factor-erythroid 2 (NF-E2) and its two putative target genes, beta1-tubulin and 3-beta-hydroxysteroid reductase. MKs express steroid receptors and some estrogen ligands, which may constitute an autocrine loop in formation of proplatelets, the cytoplasmic protrusions within which nascent blood platelets are assembled. Finally, we summarize our own studies on cellular and molecular facets of proplatelet formation and place the findings within the context of outstanding questions about mechanisms of thrombopoiesis.
Collapse
Affiliation(s)
- H Schulze
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | | |
Collapse
|
31
|
Lau LM, Wee JL, Wright MD, Moseley GW, Hogarth PM, Ashman LK, Jackson DE. The tetraspanin superfamily member CD151 regulates outside-in integrin αIIbβ3 signaling and platelet function. Blood 2004; 104:2368-75. [PMID: 15226180 DOI: 10.1182/blood-2003-12-4430] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe tetraspanin family member CD151 forms complexes with integrins and regulates cell adhesion and migration. While CD151 is highly expressed in megakaryocytes and to a lesser extent in platelets, its physiologic role in platelets is unclear. In this study, we investigate the physical and functional importance of CD151 in murine platelets. Immunoprecipitation/Western blot studies reveal a constitutive physical association of CD151 with integrin αIIbβ3 complex under strong detergent conditions. Using CD151-deficient mice, we show that the platelets have impaired “outside-in” integrin αIIbβ3 signaling with defective platelet aggregation responses to protease-activated receptor 4 (PAR-4) agonist peptide, collagen, and adenosine diphosphate (ADP); impaired platelet spreading on fibrinogen; and delayed kinetics of clot retraction in vitro. This functional integrin αIIbβ3 defect could not be attributed to altered expression of integrin αIIbβ3. CD151–/– platelets displayed normal platelet alpha granule secretion, dense granule secretion, and static platelet adhesion. In addition, CD151–/– platelets displayed normal “inside-out” integrin αIIbβ3 signaling properties as demonstrated by normal agonist-induced binding of soluble fluorescein isothiocyanate (FITC)–fibrinogen, JON/A antibody binding, and increases in cytosolic-free calcium and inositol 1,4,5 triphosphate (IP3) levels. This study provides the first direct evidence that CD151 is essential for normal platelet function and that disruption of CD151 induced a moderate outside-in integrin αIIbβ3 signaling defect.
Collapse
Affiliation(s)
- Lai-Man Lau
- Kronheimer Building, Austin Research Institute, Austin Hospital, Studley Rd, Heidelberg, Victoria 3084 Australia
| | | | | | | | | | | | | |
Collapse
|