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d’Alessandro M, Gangi S, Soccio P, Cantó E, Osuna-Gómez R, Bergantini L, Cameli P, Fabbri G, Croce S, Scioscia G, Montuori G, Fanetti M, Moriondo G, Mezzasalma F, Castillo D, Lacedonia D, Vidal S, Bargagli E. The Effects of Interstitial Lung Diseases on Alveolar Extracellular Vesicles Profile: A Multicenter Study. Int J Mol Sci 2023; 24:ijms24044071. [PMID: 36835481 PMCID: PMC9964169 DOI: 10.3390/ijms24044071] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
Diagnosis of interstitial lung diseases (ILD) is difficult to perform. Extracellular vesicles (EVs) facilitate cell-to-cell communication, and they are released by a variety of cells. Our goal aimed to investigate EV markers in bronchoalveolar lavage (BAL) from idiopathic pulmonary fibrosis (IPF), sarcoidosis and hypersensitivity pneumonitis (HP) cohorts. ILD patients followed at Siena, Barcelona and Foggia University Hospitals were enrolled. BAL supernatants were used to isolate the EVs. They were characterized by flow cytometry assay through MACSPlex Exsome KIT. The majority of alveolar EV markers were related to the fibrotic damage. CD56, CD105, CD142, CD31 and CD49e were exclusively expressed by alveolar samples from IPF patients, while HP showed only CD86 and CD24. Some EV markers were common between HP and sarcoidosis (CD11c, CD1c, CD209, CD4, CD40, CD44, CD8). Principal component analysis distinguished the three groups based on EV markers with total variance of 60.08%. This study has demonstrated the validity of the flow cytometric method to phenotype and characterize EV surface markers in BAL samples. The two granulomatous diseases, sarcoidosis and HP, cohorts shared alveolar EV markers not revealed in IPF patients. Our findings demonstrated the viability of the alveolar compartment allowing identification of lung-specific markers for IPF and HP.
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Affiliation(s)
- Miriana d’Alessandro
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
- Correspondence: or ; Tel.: +39-0577586713; Fax: +39-0577280744
| | - Sara Gangi
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
| | - Piera Soccio
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
- Institute of Respiratory Diseases, Policlinico Riuniti of Foggia, 71122 Foggia, Italy
| | - Elisabet Cantó
- Inflammatory Diseases, Biomedical Research Institute Sant Pau (IIB Sant Pau), 08041 Barcelona, Spain
| | - Rubén Osuna-Gómez
- Inflammatory Diseases, Biomedical Research Institute Sant Pau (IIB Sant Pau), 08041 Barcelona, Spain
| | - Laura Bergantini
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
| | - Paolo Cameli
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
| | - Gaia Fabbri
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
| | - Sara Croce
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
| | - Giulia Scioscia
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
- Institute of Respiratory Diseases, Policlinico Riuniti of Foggia, 71122 Foggia, Italy
| | - Giusy Montuori
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
| | - Matteo Fanetti
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
| | - Giorgia Moriondo
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
- Institute of Respiratory Diseases, Policlinico Riuniti of Foggia, 71122 Foggia, Italy
| | - Fabrizio Mezzasalma
- Diagnostic and Interventional Bronchoscopy Unit, Cardio-Thoracic and Vascular Department, University Hospital of Siena (Azienda Ospedaliera Universitaria Senese—AOUS), 53100 Siena, Italy
| | - Diego Castillo
- Respiratory Department, Hospital de la Santa Creu i Sant Pau, Sant Pau Biomedical Research Institute (IIB-Sant Pau), 08041 Barcelona, Spain
| | - Donato Lacedonia
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
- Institute of Respiratory Diseases, Policlinico Riuniti of Foggia, 71122 Foggia, Italy
| | - Silvia Vidal
- Inflammatory Diseases, Biomedical Research Institute Sant Pau (IIB Sant Pau), 08041 Barcelona, Spain
| | - Elena Bargagli
- Respiratory Diseases and Lung Transplantation Unit, Department of Medical and Surgical Sciences & Neuro-Sciences, University of Siena, 53100 Siena, Italy
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Yang X, Chitalia SV, Matsuura S, Ravid K. Integrins and their role in megakaryocyte development and function. Exp Hematol 2022; 106:31-39. [PMID: 34910941 PMCID: PMC8795491 DOI: 10.1016/j.exphem.2021.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 02/03/2023]
Abstract
Mature megakaryocytes, the platelet precursors, originate from hematopoietic stem cell progenitors, which, once committed to this lineage, undergo endomitosis leading to polyploidization. The process entails repeated rounds of DNA replication without cell division, yielding polyploid cells. Supporting the cell's developmental process and various cellular functions are integrin receptors, a conduit of communication between the extracellular environment and the cell actin cytoskeleton. Integrins are heterodimers of α and β subunits, where different combinations of the known 18 α and 8 β subunits confer specificity to the receptor. Integrin ligands range from extracellular matrices through soluble ligands, infectious agents, and counterreceptors, to cells. In this review, we describe the different integrins expressed on bone marrow megakaryocytes and their attributed roles in lineage development and cellular functions, including adhesion, spreading, proplatelet formation, and functional interaction with other cells. Pathologies associated with dysregulated megakaryocyte integrin expression are also reviewed.
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Affiliation(s)
- Xiaosheng Yang
- Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118
| | - Shlok V. Chitalia
- Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118
| | - Shinobu Matsuura
- Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118
| | - Katya Ravid
- Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118,To whom correspondence should be addressed: Katya Ravid, Boston University School of Medicine, 700 Albany St, W-6, Boston, MA 02118, Tel: (617)358-8042,
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3
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Matsuura S, Thompson CR, Ng SK, Ward CM, Karagianni A, Mazzeo C, Malara A, Balduini A, Ravid K. Adhesion to fibronectin via α5β1 integrin supports expansion of the megakaryocyte lineage in primary myelofibrosis. Blood 2020; 135:2286-2291. [PMID: 32294178 PMCID: PMC7316217 DOI: 10.1182/blood.2019004230] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/10/2020] [Indexed: 12/11/2022] Open
Abstract
Excessive accumulation of extracellular matrix (ECM) is a hallmark of bone marrow (BM) milieu in primary myelofibrosis (PMF). Because cells have the ability to adhere to the surrounding ECM through integrin receptors, we examined the hypothesis that an abnormal ECM-integrin receptor axis contributes to BM megakaryocytosis in JAK2V617F+ PMF. Secretion of ECM protein fibronectin (FN) by BM stromal cells from PMF patients correlates with fibrosis and disease severity. Here, we show that Vav1-hJAK2V617F transgenic mice (JAK2V617F+) have high BM FN content associated with megakaryocytosis and fibrosis. Further, megakaryocytes from JAK2V617F+ mice have increased cell surface expression of the α5 subunit of the α5β1 integrin, the major FN receptor in megakaryocytes, and augmented adhesion to FN compared with wild-type controls. Reducing adhesion to FN by an inhibitory antibody to the α5 subunit effectively reduces the percentage of CD41+ JAK2V617F+ megakaryocytes in vitro and in vivo. Corroborating our findings in mice, JAK2V617F+ megakaryocytes from patients showed elevated expression of α5 subunit, and a neutralizing antibody to α5 subunit reduced adhesion to FN and megakaryocyte number derived from CD34+ cells. Our findings reveal a previously unappreciated contribution of FN-α5β1 integrin to megakaryocytosis in JAK2V617F+ PMF.
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Affiliation(s)
- Shinobu Matsuura
- Department of Medicine-Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA
| | - Cristal Reyna Thompson
- Department of Medicine-Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA
| | - Seng Kah Ng
- Department of Medicine-Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA
| | - Christina Marie Ward
- Department of Medicine-Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA
| | - Aikaterini Karagianni
- Department of Medicine-Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA
- Department of Internal Medicine, School of Medicine, University of Crete, Heraklion, Greece
| | - Carla Mazzeo
- Department of Medicine-Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA
| | | | - Alessandra Balduini
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Department of Biomedical Engineering, Tufts University, Medford, MA; and
| | - Katya Ravid
- Department of Medicine-Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA
- Departments of Biochemistry and Biology, Boston University School of Medicine, Boston, MA
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β4GALT1 controls β1 integrin function to govern thrombopoiesis and hematopoietic stem cell homeostasis. Nat Commun 2020; 11:356. [PMID: 31953383 PMCID: PMC6968998 DOI: 10.1038/s41467-019-14178-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 12/13/2019] [Indexed: 12/26/2022] Open
Abstract
Glycosylation is critical to megakaryocyte (MK) and thrombopoiesis in the context of gene mutations that affect sialylation and galactosylation. Here, we identify the conserved B4galt1 gene as a critical regulator of thrombopoiesis in MKs. β4GalT1 deficiency increases the number of fully differentiated MKs. However, the resulting lack of glycosylation enhances β1 integrin signaling leading to dysplastic MKs with severely impaired demarcation system formation and thrombopoiesis. Platelets lacking β4GalT1 adhere avidly to β1 integrin ligands laminin, fibronectin, and collagen, while other platelet functions are normal. Impaired thrombopoiesis leads to increased plasma thrombopoietin (TPO) levels and perturbed hematopoietic stem cells (HSCs). Remarkably, β1 integrin deletion, specifically in MKs, restores thrombopoiesis. TPO and CXCL12 regulate β4GalT1 in the MK lineage. Thus, our findings establish a non-redundant role for β4GalT1 in the regulation of β1 integrin function and signaling during thrombopoiesis. Defective thrombopoiesis and lack of β4GalT1 further affect HSC homeostasis.
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Fibronectin in Cancer: Friend or Foe. Cells 2019; 9:cells9010027. [PMID: 31861892 PMCID: PMC7016990 DOI: 10.3390/cells9010027] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/13/2019] [Accepted: 12/18/2019] [Indexed: 01/10/2023] Open
Abstract
The role of fibronectin (FN) in tumorigenesis and malignant progression has been highly controversial. Cancerous FN plays a tumor-suppressive role, whereas it is pro-metastatic and associated with poor prognosis. Interestingly, FN matrix deposited in the tumor microenvironments (TMEs) promotes tumor progression but is paradoxically related to a better prognosis. Here, we justify how FN impacts tumor transformation and subsequently metastatic progression. Next, we try to reconcile and rationalize the seemingly conflicting roles of FN in cancer and TMEs. Finally, we propose future perspectives for potential FN-based therapeutic strategies.
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Mechanisms coupling thrombin to metastasis and tumorigenesis. Thromb Res 2018; 164 Suppl 1:S29-S33. [PMID: 29703481 DOI: 10.1016/j.thromres.2017.12.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/29/2017] [Indexed: 01/01/2023]
Abstract
The association of malignancy and thrombophilia is bidirectional, as evidenced by four decades of studies in animal models showing that hemostatic system components support cancer progression. Consistent with this view, clinical studies have suggested that anticoagulants not only limit thromboembolic complications associated with cancer, but also improve survival by impeding cancer progression, and may even prevent the development of cancer. In order to fully capitalize on this association, a detailed understanding of the mechanisms coupling hemostatic factors to cancer pathogenesis is required. Multiple studies have shown that thrombin-mediated procoagulant functions strongly promote metastatic potential. In particular, the platelet/fibrin(ogen) axis has been shown to protect newly formed micrometastases from innate immune surveillance, contribute to creation of a metastatic niche by recruitment of prometastatic inflammatory cells, and promote the epithelial to mesenchymal transition of metastatic cells. Thrombin-mediated functions have also been shown to support tumor growth in some contexts, and have even been linked to tumorigenesis in the setting of inflammation-driven colon cancer. Here, local thrombin-mediated extravascular fibrin deposition, and specifically fibrin-αMβ2 integrin interaction, push intestinal inflammatory cells toward a pro-tumorigenic phenotype, resulting in the elaboration of key cytokines and growth factors that support the proliferation and survival of transformed intestinal epithelial cells. These studies reveal that hemostatic factors can serve as a bridge between pathological inflammation and the development of cancer. As a large proportion of cancers are caused by pathological inflammation, these studies suggest that therapies targeting the nexus between hemostasis and inflammation could be used to prevent cancer development.
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7
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Leiva O, Leon C, Kah Ng S, Mangin P, Gachet C, Ravid K. The role of extracellular matrix stiffness in megakaryocyte and platelet development and function. Am J Hematol 2018; 93:430-441. [PMID: 29247535 DOI: 10.1002/ajh.25008] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/11/2017] [Accepted: 12/13/2017] [Indexed: 12/16/2022]
Abstract
The extracellular matrix (ECM) is a key acellular structure in constant remodeling to provide tissue cohesion and rigidity. Deregulation of the balance between matrix deposition, degradation, and crosslinking results in fibrosis. Bone marrow fibrosis (BMF) is associated with several malignant and nonmalignant pathologies severely affecting blood cell production. BMF results from abnormal deposition of collagen fibers and enhanced lysyl oxidase-mediated ECM crosslinking within the marrow, thereby increasing marrow stiffness. Bone marrow stiffness has been recently recognized as an important regulator of blood cell development, notably by modifying the fate and differentiation process of hematopoietic or mesenchymal stem cells. This review surveys the different components of the ECM and their influence on stem cell development, with a focus on the impact of the ECM composition and stiffness on the megakaryocytic lineage in health and disease. Megakaryocyte maturation and the biogenesis of their progeny, the platelets, are thought to respond to environmental mechanical forces through a number of mechanosensors, including integrins and mechanosensitive ion channels, reviewed here.
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Affiliation(s)
- Orly Leiva
- Department of Medicine; Whitaker Cardiovascular Institute, Boston University School of Medicine; Boston Massachusetts
| | - Catherine Leon
- Université de Strasbourg, INSERM, EFS Grand-Est, BPPS UMR-S 949, FMTS; Strasbourg F-67000 France
| | - Seng Kah Ng
- Department of Medicine; Whitaker Cardiovascular Institute, Boston University School of Medicine; Boston Massachusetts
| | - Pierre Mangin
- Université de Strasbourg, INSERM, EFS Grand-Est, BPPS UMR-S 949, FMTS; Strasbourg F-67000 France
| | - Christian Gachet
- Université de Strasbourg, INSERM, EFS Grand-Est, BPPS UMR-S 949, FMTS; Strasbourg F-67000 France
| | - Katya Ravid
- Department of Medicine; Whitaker Cardiovascular Institute, Boston University School of Medicine; Boston Massachusetts
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Abstract
The hematopoietic microenvironment, and in particular the hematopoietic stromal cell element, are intimately involved in megakaryocyte development. The process of megakaryocytopoiesis occurs within a complex bone marrow microenvironment where adhesive interactions, chemokines, as well as cytokines play a pivotal role. Here we review the effect of stromal cells and cytokines on megakaryocytopoiesis with the aim of exploring new therapeutic strategies for platelet recovery after hematopoietic stem cell transplantation (HSCT).
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Affiliation(s)
- Yimei Feng
- Department of Hematology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
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9
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Megakaryocyte-matrix interaction within bone marrow: new roles for fibronectin and factor XIII-A. Blood 2010; 117:2476-83. [PMID: 21131589 DOI: 10.1182/blood-2010-06-288795] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The mechanisms by which megakaryocytes (MKs) differentiate and release platelets into the circulation are not well understood. However, growing evidence indicates that a complex regulatory mechanism involving MK-matrix interactions may contribute to the quiescent or permissive microenvironment related to platelet release within bone marrow. To address this hypothesis, in this study we demonstrate that human MKs express and synthesize cellular fibronectin (cFN) and transglutaminase factor XIII-A (FXIII-A). We proposed that these 2 molecules are involved in a new regulatory mechanism of MK-type I collagen interaction in the osteoblastic niche. In particular, we demonstrate that MK adhesion to type I collagen promotes MK spreading and inhibits pro-platelet formation through the release and relocation to the plasma membrane of cFN. This regulatory mechanism is dependent on the engagement of FN receptors at the MK plasma membrane and on transglutaminase FXIII-A activity. Consistently, the same mechanism regulated the assembly of plasma FN (pFN) by adherent MKs to type I collagen. In conclusion, our data extend the knowledge of the mechanisms that regulate MK-matrix interactions within the bone marrow environment and could serve as an important step for inquiring into the origins of diseases such as myelofibrosis and congenital thrombocytopenias that are still poorly understood.
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Thrombospondin-1 is not the major activator of TGF-β1 in thrombopoietin-induced myelofibrosis. Blood 2010; 117:246-9. [PMID: 20944070 DOI: 10.1182/blood-2010-07-294447] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transforming growth factor-β1 (TGF-β1) is the most important cytokine involved in the promotion of myelofibrosis. Mechanisms leading to its local activation in the bone marrow environment remain unclear. As a recent study has highlighted the role of thrombospondin-1 (TSP-1) in platelet-derived TGF-β1 activation, we investigated the role of TSP-1 in the TPO(high) murine model of myelofibrosis. Two groups of engrafted mice, WT TPO(high) and Tsp-1-null TPO(high), were constituted. All mice developed a similar myeloproliferative syndrome and an increase in total TGF-β1 levels in the plasma and in extracellular fluids of marrow and spleen. Surprisingly, we were able to detect the active form of TGF-β1 in Tsp-1-null TPO(high) mice. Accordingly, these mice developed marrow and spleen fibrosis, with intriguingly a higher grade than in WT TPO(high) mice. Our results show that TSP-1 is not the major activator of TGF-β1 in TPO-induced myelofibrosis, suggesting the contribution of another mechanism in the megakaryocyte/platelet compartment.
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12
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Steinbrecher KA, Horowitz NA, Blevins EA, Barney KA, Shaw MA, Harmel-Laws E, Finkelman FD, Flick MJ, Pinkerton MD, Talmage KE, Kombrinck KW, Witte DP, Palumbo JS. Colitis-associated cancer is dependent on the interplay between the hemostatic and inflammatory systems and supported by integrin alpha(M)beta(2) engagement of fibrinogen. Cancer Res 2010; 70:2634-43. [PMID: 20233870 PMCID: PMC4288842 DOI: 10.1158/0008-5472.can-09-3465] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A link between colitis and colon cancer is well established, but the mechanisms regulating inflammation in this context are not fully defined. Given substantial evidence that hemostatic system components are powerful modulators of both inflammation and tumor progression, we used gene-targeted mice to directly test the hypothesis that the coagulation factor fibrinogen contributes to colitis-associated colon cancer in mice. This fundamental provisional matrix protein was found to be an important determinant of colon cancer. Fibrinogen deficiency resulted in a dramatic diminution in the number of colonic adenomas formed following azoxymethane/dextran sodium sulfate challenge. More detailed analyses in mice expressing a mutant form of fibrinogen that retains clotting function, but lacks the leukocyte integrin receptor alpha(M)beta(2) binding motif (Fibgamma(390-396A)), revealed that alpha(M)beta(2)-mediated engagement of fibrin(ogen) is mechanistically coupled to local inflammatory processes (e.g., interleukin-6 elaboration) and epithelial alterations that contribute to adenoma formation. Consistent with these findings, the majority of Fibgamma(390-396A) mice developed no discernable adenomas, whereas penetrance was 100% in controls. Furthermore, the adenomas harvested from Fibgamma(390-396A) mice were significantly smaller than those from control mice and less proliferative based on quantitative analyses of mitotic indices, suggesting an additional role for fibrin(ogen) in the growth of established adenomas. These studies show, for the first time, a unique link between fibrin(ogen) and the development of inflammation-driven malignancy. Given the importance of antecedent inflammation in the progression of numerous cancers, these studies suggest that therapies targeting fibrin(ogen)-alpha(M)beta(2) interactions may be useful in preventing and/or treating this important subset of malignancies.
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Affiliation(s)
- Kris A Steinbrecher
- Divisions of Gastroenterology, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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Eto K, Nishikii H, Ogaeri T, Suetsugu S, Kamiya A, Kobayashi T, Yamazaki D, Oda A, Takenawa T, Nakauchi H. The WAVE2/Abi1 complex differentially regulates megakaryocyte development and spreading: implications for platelet biogenesis and spreading machinery. Blood 2007; 110:3637-47. [PMID: 17664349 DOI: 10.1182/blood-2007-04-085860] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Actin polymerization is crucial in throm-bopoiesis, platelet adhesion, and mega-karyocyte (MK) and platelet spreading. The Wiskott-Aldrich syndrome protein (WASp) homolog WAVE functions downstream of Rac and plays a pivotal role in lamellipodia formation. While MKs and platelets principally express WAVE1 and WAVE2, which are associated with Abi1, the physiologic significance of WAVE isoforms remains undefined. We generated WAVE2−/− embryonic stem (ES) cells because WAVE2-null mice die by embryonic day (E) 12.5. We found that while WAVE2−/− ES cells differentiated into immature MKs on OP9 stroma, they were severely impaired in terminal differentiation and in platelet production. WAVE2−/− MKs exhibited a defect in peripheral lamellipodia on fibrinogen even with phorbol 12-myristate 13-acetate (PMA) costimulation, indicating a requirement of WAVE2 for integrin αIIbβ3-mediated full spreading. MKs in which expression of Abi1 was reduced by small interfering RNA (siRNA) exhibited striking similarity to WAVE2−/− MKs in maturation and spreading. Interestingly, the knockdown of IRSp53, a Rac effector that preferentially binds to WAVE2, impaired the development of lamellipodia without affecting proplatelet production. In contrast, thrombopoiesis in vivo and platelet spreading on fibrinogen in vitro were intact in WAVE1-null mice. These observations clarify indispensable roles for the WAVE2/Abi1 complex in αIIbβ3-mediated lamellipodia by MKs and platelets through Rac and IRSp53, and additionally in thrombopoiesis independent of Rac and IRSp53.
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Affiliation(s)
- Koji Eto
- Laboratory of Stem Cell Therapy, Center for Experimental Medicine, The Institute of Medical Science, University of Tokyo, Japan.
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Hoffmann S, Zhou L, Gu Y, Davenport R, Cooling L. Delayed platelet engraftment in group O patients after autologous progenitor cell transplantation. Transfusion 2005; 45:885-95. [PMID: 15934986 DOI: 10.1111/j.1537-2995.2005.04346.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Fucosylated glycans, including H-antigen, play critical roles in hematopoietic progenitor cell homing, adhesion, growth, and differentiation. H-active antigens are strongly expressed on CD34+ progenitor cells and committed megakaryocytic progenitors and may mediate adhesion to marrow stromal fibroblasts. We examined the possible influence of donor ABO type on platelet (PLT) engraftment after autologous peripheral blood progenitor cell transplant (PBPCT). STUDY DESIGN AND METHODS A retrospective analysis of all patients who underwent a single autologous PBPCT between 1996 and 2000 were reviewed. Neutrophil and PLT engraftment were compared by patient ABO type and CD34+ cell dose by t test, chi-square test, analysis of variance, Kaplan-Meier probability, and log-rank test. RESULTS Engraftment data was available in 195 patients. PLT engraftment was delayed in all patients, regardless of ABO type, at CD34+ PBPC doses of 2x10(6) to 3x10(6) per kg (p<0.001). When examined by ABO type, late PLT engraftment (PLT count>50x10(9)/L) was significantly delayed in group O patients relative to all non-group O patients (32.4 days vs. 19.6 days, p<0.001). Approximately 50 percent of group O patients required more than 40 days to achieve late PLT recovery (p<0.005). CONCLUSIONS A group O phenotype may be associated with delayed PLT engraftment at lower CD34 doses.
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Affiliation(s)
- Sandra Hoffmann
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
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15
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Gonzalez AL, Gobin AS, West JL, McIntire LV, Smith CW. Integrin interactions with immobilized peptides in polyethylene glycol diacrylate hydrogels. ACTA ACUST UNITED AC 2005; 10:1775-86. [PMID: 15684686 DOI: 10.1089/ten.2004.10.1775] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This study employs tissue-engineering technologies to evaluate neutrophil interactions with extracellular matrix (ECM)-mimetic peptides. We have used a polyethylene glycol (PEG) diacrylate derivative to form a hydrogel as a biologically inert surface. Covalent attachment of bioactive moieties to the hydrogel makes it bioactive. The goal is to define the mechanisms by which these moieties influence the interactions of neutrophils with this bioactive hydrogel, and thus understand the likely effects of similar ligands in the ECM. The current experiments analyze the interactions of isolated human neutrophils with PEG hydrogels modified with Arg-Gly-Asp-Ser (RGDS), a known ligand for some beta(1) and beta(3) integrins, and Thr-Met-Lys-Ile-Ile-Pro-Phe-Asn-Arg-Leu-Thr-Ile-Gly-Gly (TMKIIPFNRLTIGG), a ligand for Mac-1, a beta(2) integrin. Our results demonstrate that neutrophils, independent of chemotactic stimulation, show little ability to adhere to unmodified PEG hydrogels. However, cell adhesion and spreading are robust on peptide-modified hydrogels. Incorporating distinct bioactive peptides, either alone or in combination, has enabled recognition of differential functions of alpha(v)beta(3), beta(1), and beta(2) integrins on neutrophil adhesion and spreading. Combined interactions result in activity that differs markedly from that seen with either integrin independently engaged. This model allows investigation of specific ligand-induced leukocyte functions and the development of engineered matrices with defined bioactive properties.
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Affiliation(s)
- Anjelica L Gonzalez
- Section of Leukocyte Biology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
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Fox NE, Kaushansky K. Engagement of integrin alpha4beta1 enhances thrombopoietin-induced megakaryopoiesis. Exp Hematol 2005; 33:94-9. [PMID: 15661402 DOI: 10.1016/j.exphem.2004.10.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Revised: 10/01/2004] [Accepted: 10/04/2004] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Studies in numerous adherent cell systems have indicated that engagement of integrins is required for cell survival and proliferation. Although not classically thought of as an adherent cell type, megakaryocytes in the marrow develop in juxtaposition to endothelial cells which display a number of integrin counter-receptors. Moreover, a number of other hematopoietic cell types, including stem cells and erythroid progenitors, have been shown to engage and be affected by integrin ligands. METHODS The role of beta1 integrins in thrombopoietin-mediated megakaryopoiesis was studied using both gain-of-function and loss-of-function strategies. RESULTS We found that pan-blockade of integrins with a relatively nonspecific disintegrin blocked TPO-induced MK growth, but that an alpha5beta1 disintegrin, and a function-blocking monoclonal antibody, failed to affect megakaryopoiesis in vitro. In contrast, a neutralizing alpha4beta1 monoclonal antibody blocked TPO-induced MK growth, and an integrin alpha4beta1 ligand, the H296 fragment of fibronectin, enhanced MK growth at all concentrations of TPO. CONCLUSIONS These findings have important implications for thrombopoiesis in general, and potentially for the enhanced platelet production found in states of systemic inflammation and following the use of therapeutic strategies designed to block alpha4beta1 integrin engagement in states of chronic inflammation and autoimmunity.
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Affiliation(s)
- Norma E Fox
- Department of Medicine, University of California San Diego, 92103-8811, USA
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17
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Decraene C, Garçon L, Lacout C, Sabri S, Auffray C, Vainchenker W, Duménil D, Piétu G, Svinartchuk F. Zyxin is up-regulated during megakaryocytic differentiation of human UT-7/c-mpl cells. Biochem Biophys Res Commun 2004; 318:439-43. [PMID: 15120620 DOI: 10.1016/j.bbrc.2004.04.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Indexed: 11/20/2022]
Abstract
To characterize genes involved in megakaryocytic commitment, we compared expression profiles of bipotent cells (UT-7/c-mpl) with those of the same cells induced to differentiate towards megakaryopoiesis in the presence of TPO. Using cDNA arrays, we showed that 12 out of 2260 genes changed their expression level after 6h of TPO stimulation. One of these genes encodes for zyxin, a cytoskeleton protein component. Zyxin is up-regulated at the mRNA and protein levels in UT-7/c-mpl cells in response to TPO confirming the reliability of the cDNA array technology. Similarly, when CD34 positive cells were induced to differentiate into megakaryocytes, zyxin mRNA was accumulated. Furthermore, when megakaryocytes were allowed to spread on fibrinogen, formation of stress fibers and lamellipodia was induced and zyxin was localized at the picks of actin stress fibers. These results suggest an important role for zyxin during megakaryocytic differentiation and more precisely in the regulation of the integrin mediated adhesion process in megakaryocytes.
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Affiliation(s)
- C Decraene
- Genexpress, CNRS ERS1984, BP8, 94801 Villejuif, France
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18
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Aguzzi MS, Giampietri C, De Marchis F, Padula F, Gaeta R, Ragone G, Capogrossi MC, Facchiano A. RGDS peptide induces caspase 8 and caspase 9 activation in human endothelial cells. Blood 2004; 103:4180-7. [PMID: 14982875 DOI: 10.1182/blood-2003-06-2144] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AbstractPeptides containing the Arg-Gly-Asp (RGD) motif inhibit cell adhesion and exhibit a variety of other biologic effects including anticoagulant and antimetastatic activities. The aim of the present study was to examine the anchorage-independent effects of an RGD-containing peptide, Arg-Gly-Asp-Ser (RGDS), on human umbilical vein endothelial cells (HUVECs). Assays were performed on HUVECs seeded onto collagen IV; under these experimental conditions RGDS did not exert antiadhesive effects but significantly reduced FGF-2-dependent chemotaxis after 4 hours of treatment and reduced proliferation after 24 hours of treatment. Experiments carried out with caspase-specific inhibitors indicated that the observed antichemotactic effects required caspase 8 and caspase 9 activation. RGDS activated both caspase 8 and caspase 9 after 4 hours of treatment and caspase 3 after 24 hours of treatment, and markedly enhanced HUVEC apoptosis by transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)/Hoechst staining and fluorescence-activated cell sorting (FACS) analysis. Finally, confocal microscopy showed that RGDS localizes in the cytoplasm of live HUVECs within 4 hours and in vitro experiments showed that RGDS directly interacts with recombinant caspases 8 and 9 in a specific way. In summary, these results indicate that RGDS directly binds and activates caspases 8 and 9, inhibits chemotaxis, and induces apoptosis of HUVECs with a mechanism independent from its antiadhesive effect.
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Affiliation(s)
- Maria Simona Aguzzi
- Laboratorio Patologia Vascolare, Istituto Dermopatico dell'Immacolata, IDI, Rome, Italy
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19
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Coelho ALJ, De Freitas MS, Mariano-Oliveira A, Rapozo DCM, Pinto LFR, Niewiarowski S, Zingali RB, Marcinkiewicz C, Barja-Fidalgo C. RGD- and MLD-disintegrins, jarastatin and EC3, activate integrin-mediated signaling modulating the human neutrophils chemotaxis, apoptosis and IL-8 gene expression. Exp Cell Res 2004; 292:371-84. [PMID: 14697344 DOI: 10.1016/j.yexcr.2003.09.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects of jarastatin (JT), a monomeric RGD-disintegrin, were compared with those of the heterodimeric MLD-disintegrin, EC3, on human neutrophil activation and functions. Both disintegrins inhibited neutrophil chemotaxis induced by fMet-Leu-Phe and were also potent chemotactic agents. These effects were accompanied by an increase in actin polymerization, and both were inhibited by genistein, a tyrosine kinase inhibitor. While JT, but not other RGD-disintegrins, inhibited EC3-induced chemotaxis, EC3 was not able to inhibit JT effect. The chemotactic effect of JT was blocked by anti-alpha(M) antibody whereas anti-alpha(9)beta(1) inhibited EC3 effect. Both JT and EC3 induced focal adhesion kinase (FAK) and phosphoinositide 3-kinase (PI3K) activation. Accordingly, LY294002, a PI3K inhibitor, impaired their chemotactic effect on neutrophils. JT induced Erk-2 translocation to nucleus and a delay of the spontaneous apoptosis of neutrophils in vitro. In contrast, EC3 inhibited Erk-2 activation and had a proapoptotic effect. These effects were reverted by PD98059, an MEK 1/2 inhibitor and blocked by z-VAD-FMK, a caspase inhibitor. In addition, JT, but not EC3, increased the IL-8 mRNA levels in neutrophils. The data indicate that JT and EC3 directly activate an integrin-coupled signaling and modulate the MAPK pathway in different ways, leading the neutrophils to express different functional response.
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Affiliation(s)
- Ana Lucia J Coelho
- Departamento de Farmacologia, Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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20
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Affiliation(s)
- D H Sachs
- Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Department of Medicine, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts 02129, USA
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21
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Sahara M, Inoue S, Sunaga S, Kitagawa H, Ako J, Hoshino S, Toba K, Ouchi Y. Megakaryoblastic transformation of chronic myelomonocytic leukemia presenting with severe bone pain. Geriatr Gerontol Int 2002. [DOI: 10.1046/j.1444-1586.2002.00027.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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22
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Abstract
Induction of mixed chimerism has the potential to overcome the current limitations of transplantation, namely chronic rejection, complications of immunosuppressive therapy and the need for xenografts to overcome the current shortage of allogeneic organs. Successful achievement of mixed chimerism had been shown to tolerize T cells, B cells and possibly natural killer cells, the lymphocyte subsets that pose major barriers to allogeneic and xenogeneic transplants. Current understanding of the mechanisms involved in tolerization of each cell type is reviewed. Considerable advances have been made in reducing the potential toxicity of conditioning regimens required for the induction of mixed chimerism in rodent models, and translation of these strategies to large animal models and in a patient are important advances toward more widespread clinical application of the mixed chimerism approach for tolerance induction.
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Affiliation(s)
- M Sykes
- Transplantation Biology Research Center, Surgical Service, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA.
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23
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Wickenhauser C, Schmitz B, Baldus SE, Henze F, Farahmand P, Frimpong S, Thiele J, Fischer R. Selectins (CD62L, CD62P) and megakaryocytic glycoproteins (CD41a, CD42b) mediate megakaryocyte-fibroblast interactions in human bone marrow. Leuk Res 2000; 24:1013-21. [PMID: 11077115 DOI: 10.1016/s0145-2126(00)00063-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Previous in vitro studies are in keeping with the finding that isolated and enriched megakaryocytes attach to bone marrow fibroblasts and generate an increased growth of these cells. This process was assumed to depend on a close spatial relationship between both cell types which supports the paracrine effect of platelet-derived growth factor (PDGF) and transforming growth factor (TGF)-beta1. Moreover, adhesion molecules including beta1 integrin receptors and fucosylated structures were determined to play an important role in these complex interactions. However, up to now the influence of megakaryocyte expressed glycoproteins CD41a and CD42b in these processes was not investigated. In addition, the role of megakaryocytic CD62P and also of CD62L, both adhesion molecules of the selectin group, could also be of interest. Following isolation and enrichment of bone marrow megakaryocytes and fibroblasts, both cell populations were characterized regarding their expression of these factors by applying immunocytochemical techniques. Additionally, their influence on adhesion of megakaryocytes to fibroblasts as well as fibroblast growth was evaluated by comparative megakaryocyte-fibroblast co-cultures and inhibition studies using specific monoclonal antibodies (mabs). Fibroblast monocultures served as controls. In these experiments, selectin-specific antibodies significantly reduced megakaryocyte attachment to fibroblast feeder layers and fibroblast growth in the co-cultures. The effect of CD41a and CD42b specific antibodies was limited to megakaryocyte-dependent fibroblast growth. These results elucidate the involvement of the selectins CD62P and CD62L in the basal activation of megakaryocytes inducing their attachment to bone marrow fibroblasts. In contrast, the megakaryocyte glycoproteins CD41a and CD42b exert their effect on the megakaryocyte dependent fibroblast growth. Altogether, it is tempting to speculate that the various interactions of these mediators reflect certain steps in the complex pathomechanisms causing the evolution of (reactive) myelofibrosis in hematopoietic neoplasias accompanied by megakaryocytic proliferation.
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Affiliation(s)
- C Wickenhauser
- Institute of Pathology, University of Cologne, Joseph-Stelzmann-Str. 9, D-50934, Cologne, Germany.
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24
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Shiraga M, Ritchie A, Aidoudi S, Baron V, Wilcox D, White G, Ybarrondo B, Murphy G, Leavitt A, Shattil S. Primary megakaryocytes reveal a role for transcription factor NF-E2 in integrin alpha IIb beta 3 signaling. J Cell Biol 1999; 147:1419-30. [PMID: 10613901 PMCID: PMC2174239 DOI: 10.1083/jcb.147.7.1419] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/1999] [Accepted: 11/24/1999] [Indexed: 01/10/2023] Open
Abstract
Platelet integrin alphaIIbbeta3 responds to intracellular signals by binding fibrinogen and triggering cytoskeletal reorganization, but the mechanisms of alphaIIbbeta3 signaling remain poorly understood. To better understand this process, we established conditions to study alphaIIbbeta3 signaling in primary murine megakaryocytes. Unlike platelets, these platelet precursors are amenable to genetic manipulation. Cytokine-stimulated bone marrow cultures produced three arbitrary populations of alphaIIbbeta3-expressing cells with increasing size and DNA ploidy: small progenitors, intermediate-size young megakaryocytes, and large mature megakaryocytes. A majority of the large megakaryocytes bound fibrinogen in response to agonists, while almost none of the smaller cells did. Fibrinogen binding to large megakaryocytes was inhibited by Sindbis virus-mediated expression of isolated beta3 integrin cytoplasmic tails. Strikingly, large megakaryocytes from mice deficient in the transcription factor NF-E2 failed to bind fibrinogen in response to agonists, despite normal surface expression of alphaIIbbeta3. Furthermore, while megakaryocytes from wild-type mice spread on immobilized fibrinogen and exhibited filopodia, lamellipodia and Rho-dependent focal adhesions and stress fibers, NF-E2-deficient megakaryocytes adhered poorly. These studies establish that agonist-induced activation of alphaIIbbeta3 is controlled by NF-E2-regulated signaling pathways that mature late in megakaryocyte development and converge at the beta3 cytoplasmic tail. Megakaryocytes provide a physiologically relevant and tractable system for analysis of bidirectional alphaIIbbeta3 signaling.
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Affiliation(s)
- Masamichi Shiraga
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Alec Ritchie
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Sallouha Aidoudi
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Veronique Baron
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - David Wilcox
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Gilbert White
- Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | | | - George Murphy
- Department of Laboratory Medicine, The University of California at San Francisco, San Francisco, California 94143
| | - Andrew Leavitt
- Department of Laboratory Medicine, The University of California at San Francisco, San Francisco, California 94143
| | - Sanford Shattil
- Department of Vascular Biology, The Scripps Research Institute, La Jolla, California 92037
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25
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Ex Vivo Cultured Megakaryocytes Express Functional Glycoprotein IIb-IIIa Receptors and Are Capable of Adenovirus-Mediated Transgene Expression. Blood 1999. [DOI: 10.1182/blood.v94.12.4084.424k28_4084_4092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Investigation of the molecular basis of megakaryocyte (MK) and platelet biology has been limited by an inadequate source of genetically manipulable cells exhibiting physiologic MK and platelet functions. We hypothesized that ex vivo cultured MKs would exhibit agonist inducible glycoprotein (GP) IIb-IIIa activation characteristic of blood platelets and that these cultured MKs would be capable of transgene expression. Microscopic and flow cytometric analyses confirmed that human hematopoietic stem cells cultured in the presence of pegylated recombinant human MK growth and development factor (PEG-rHuMGDF) differentiated into morphologic and phenotypic MKs over 2 weeks. Cultured MKs expressed functional GPIIb-IIIa receptors as assessed by agonist inducible soluble fibrinogen and PAC1 binding. The specificity and kinetics of fibrinogen binding to MK GPIIb-IIIa receptors were similar to those described for blood platelets. The reversibility and internalization of ligands bound to MK GPIIb-IIIa also shared similarities with those observed in platelets. Cultured MKs were transduced with an adenoviral vector encoding green fluorescence protein (GFP) or β-galactosidase (β-gal). Efficiency of gene transfer increased with increasing multiplicities of infection and incubation time, with 45% of MKs expressing GFP 72 hours after viral infection. Transduced MKs remained capable of agonist induced GPIIb-IIIa activation. Thus, ex vivo cultured MKs (1) express agonist responsive GPIIb-IIIa receptors, (2) are capable of expressing transgenes, and (3) may prove useful for investigation of the molecular basis of MK differentiation and GPIIb-IIIa function.
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26
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Ex Vivo Cultured Megakaryocytes Express Functional Glycoprotein IIb-IIIa Receptors and Are Capable of Adenovirus-Mediated Transgene Expression. Blood 1999. [DOI: 10.1182/blood.v94.12.4084] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractInvestigation of the molecular basis of megakaryocyte (MK) and platelet biology has been limited by an inadequate source of genetically manipulable cells exhibiting physiologic MK and platelet functions. We hypothesized that ex vivo cultured MKs would exhibit agonist inducible glycoprotein (GP) IIb-IIIa activation characteristic of blood platelets and that these cultured MKs would be capable of transgene expression. Microscopic and flow cytometric analyses confirmed that human hematopoietic stem cells cultured in the presence of pegylated recombinant human MK growth and development factor (PEG-rHuMGDF) differentiated into morphologic and phenotypic MKs over 2 weeks. Cultured MKs expressed functional GPIIb-IIIa receptors as assessed by agonist inducible soluble fibrinogen and PAC1 binding. The specificity and kinetics of fibrinogen binding to MK GPIIb-IIIa receptors were similar to those described for blood platelets. The reversibility and internalization of ligands bound to MK GPIIb-IIIa also shared similarities with those observed in platelets. Cultured MKs were transduced with an adenoviral vector encoding green fluorescence protein (GFP) or β-galactosidase (β-gal). Efficiency of gene transfer increased with increasing multiplicities of infection and incubation time, with 45% of MKs expressing GFP 72 hours after viral infection. Transduced MKs remained capable of agonist induced GPIIb-IIIa activation. Thus, ex vivo cultured MKs (1) express agonist responsive GPIIb-IIIa receptors, (2) are capable of expressing transgenes, and (3) may prove useful for investigation of the molecular basis of MK differentiation and GPIIb-IIIa function.
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