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Fasouli ES, Katsantoni E. Age-associated myeloid malignancies - the role of STAT3 and STAT5 in myelodysplastic syndrome and acute myeloid leukemia. FEBS Lett 2024. [PMID: 39048534 DOI: 10.1002/1873-3468.14985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 06/08/2024] [Accepted: 06/17/2024] [Indexed: 07/27/2024]
Abstract
In the last few decades, the increasing human life expectancy has led to the inflation of the elderly population and consequently the escalation of age-related disorders. Biological aging has been associated with the accumulation of somatic mutations in the Hematopoietic Stem Cell (HSC) compartment, providing a fitness advantage to the HSCs leading to clonal hematopoiesis, that includes non-malignant and malignant conditions (i.e. Clonal Hematopoiesis of Indeterminate Potential, Myelodysplastic Syndrome and Acute Myeloid Leukemia). The Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) pathway is a key player in both normal and malignant hematopoiesis. STATs, particularly STAT3 and STAT5, are greatly implicated in normal hematopoiesis, immunity, inflammation, leukemia, and aging. Here, the pleiotropic functions of JAK-STAT pathway in age-associated hematopoietic defects and of STAT3 and STAT5 in normal hematopoiesis, leukemia, and inflammaging are reviewed. Even though great progress has been made in deciphering the role of STATs, further research is required to provide a deeper understanding of the molecular mechanisms of leukemogenesis, as well as novel biomarkers and therapeutic targets for improved management of age-related disorders.
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Affiliation(s)
- Eirini Sofia Fasouli
- Biomedical Research Foundation, Academy of Athens, Basic Research Center, Athens, Greece
| | - Eleni Katsantoni
- Biomedical Research Foundation, Academy of Athens, Basic Research Center, Athens, Greece
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2
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Zhang M, Meng Y, Ying Y, Zhou P, Zhang S, Fang Y, Yao Y, Li D. Selective activation of STAT3 and STAT5 dictates the fate of myeloid progenitor cells. Cell Death Discov 2023; 9:274. [PMID: 37507383 PMCID: PMC10382539 DOI: 10.1038/s41420-023-01575-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/20/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
The molecular programs that govern the directed differentiation of myeloid progenitor cells are still poorly defined. Using a previously established immortalized, phenotypically normal myeloid progenitor cell model mEB8-ER, we unveil a new mechanism mediated by STAT5 and STAT3 at a bifurcation point of myeloid progenitor cell-fate specification. We find that myeloid progenitor cells can spontaneously differentiate into neutrophils with a basal level of STAT3 phosphorylation, which is enhanced by G-CSF treatment or STAT3 over-expression, leading to elevated neutrophil differentiation. Reduced STAT3 phosphorylation caused by GM-CSF treatment, STAT3 specific inhibitor, or STAT3 depletion leads to attenuated myeloid differentiation into neutrophils, while elevating differentiation into monocytes/macrophages. In contrast, STAT5 appears to have an antagonistic function to STAT3. When activated by GM-CSF, STAT5 promotes myeloid differentiation into monocytes/macrophages but inhibits neutrophil differentiation. At the mechanistic level, GM-CSF activates STAT5 to up-regulate SOCS3, which attenuates STAT3 phosphorylation and consequently neutrophil differentiation, while enhancing monocyte/macrophage differentiation. Furthermore, inhibition of STAT5 and STAT3 in primary myeloid progenitors recapitulates the results from the mEB8-ER model. Together, our findings provide new mechanistic insights into myeloid differentiation and may prove useful for the diagnosis and treatment of diseases related to abnormal myeloid differentiation.
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Affiliation(s)
- Meichao Zhang
- Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yiling Meng
- Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yingxia Ying
- Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Pingting Zhou
- Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Suning Zhang
- Department of Emergency, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yong Fang
- Department of Burns and Plastic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
| | - Yuan Yao
- Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
| | - Dong Li
- Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
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3
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Smith MR, Satter LRF, Vargas-Hernández A. STAT5b: A master regulator of key biological pathways. Front Immunol 2023; 13:1025373. [PMID: 36755813 PMCID: PMC9899847 DOI: 10.3389/fimmu.2022.1025373] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/29/2022] [Indexed: 01/25/2023] Open
Abstract
The Signal Transducer and Activator of Transcription (STAT)-5 proteins are required in immune regulation and homeostasis and play a crucial role in the development and function of several hematopoietic cells. STAT5b activation is involved in the expression of genes that participate in cell development, proliferation, and survival. STAT5a and STAT5b are paralogs and only human mutations in STAT5B have been identified leading to immune dysregulation and hematopoietic malignant transformation. The inactivating STAT5B mutations cause impaired post-natal growth, recurrent infections and immune dysregulation, whereas gain of function somatic mutations cause dysregulated allergic inflammation. These mutations are rare, and they are associated with a wide spectrum of clinical manifestations which provide a disease model elucidating the biological mechanism of STAT5 by studying the consequences of perturbations in STAT5 activity. Further, the use of Jak inhibitors as therapy for a variety of autoimmune and malignant disorders has increased substantially heading relevant lessons for the consequences of Jak/STAT immunomodulation from the human model. This review summarizes the biology of the STAT5 proteins, human disease associate with molecular defects in STAT5b, and the connection between aberrant activation of STAT5b and the development of certain cancers.
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Affiliation(s)
- Madison R. Smith
- Department of Pediatrics, Division of Immunology, Allergy, and Retrovirology, Baylor College of Medicine, Houston, TX, United States,William T. Shearer Texas Children’s Hospital Center for Human Immunobiology, Houston, TX, United States
| | - Lisa R. Forbes Satter
- Department of Pediatrics, Division of Immunology, Allergy, and Retrovirology, Baylor College of Medicine, Houston, TX, United States,William T. Shearer Texas Children’s Hospital Center for Human Immunobiology, Houston, TX, United States
| | - Alexander Vargas-Hernández
- Department of Pediatrics, Division of Immunology, Allergy, and Retrovirology, Baylor College of Medicine, Houston, TX, United States,William T. Shearer Texas Children’s Hospital Center for Human Immunobiology, Houston, TX, United States,*Correspondence: Alexander Vargas-Hernández,
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4
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Fan X, Krzyzanski W, Wong RSM, Yan X. Fate determination role of erythropoietin and romiplostim in the lineage commitment of hematopoietic progenitors. J Pharmacol Exp Ther 2022; 382:31-43. [PMID: 35489782 DOI: 10.1124/jpet.122.001130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/13/2022] [Indexed: 11/22/2022] Open
Abstract
Erythropoietin (EPO) and thrombopoietin (TPO) have long been known to promote erythropoiesis and megakaryopoiesis, respectively. However, the fate changing role of EPO and TPO on megakaryocyte-erythroid progenitors (MEPs) to develop along the erythroid versus megakaryocyte (MK) lineage remains unclear. We have previously shown that EPO may have fate changing role because EPO treatment could induce progenitor cells depletion and resulted in EPO resistance. Therefore, we hypothesize that a combination of romiplostim, a TPO receptor agonist that could stimulate the expansion of progenitors, with EPO can treat EPO resistance. Using rats with anemia due to chronic kidney disease, we demonstrated that romiplostim synergized with EPO to promote red blood cells production while EPO inhibited platelet production in a dose-dependent manner to reduce the risk of thrombosis. Corroborating findings from in vivo, in vitro experiments demonstrated that romiplostim expanded hematopoietic stem cells and stimulated megakaryopoiesis, while EPO drove the progenitors toward an erythroid fate. We further developed a novel pharmacokinetic-pharmacodynamic model to quantify the effects of EPO and romiplostim on megakaryopoiesis and erythropoiesis simultaneously. The modeling results demonstrated that EPO increased the differentiation rate of MEPs into burst-forming unit-erythroid up to 22-fold, indicating that the slight increase of MEPs induced by romiplostim could be further amplified and recruited by EPO to promote erythropoiesis. The data herein support that romiplostim in combination with EPO can treat EPO resistance. Significance Statement This study clarified that erythropoietin (EPO) drives the fate of megakaryocyte-erythroid progenitors (MEP) toward the erythroid lineage, thus reducing their megakaryocyte (MK) lineage commitment, whereas romiplostim, a thrombopoietin (TPO) receptor agonist (RA), stimulates megakaryopoiesis through the MK-committed progenitor and MEP bifurcation pathways simultaneously. These findings support an innovative combination of romiplostim and EPO to treat EPO-resistant anemia, because the combination therapy further promotes erythropoiesis compared to EPO monotherapy and inhibit platelet production compared to romiplostim monotherapy.
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Affiliation(s)
- Xiaoqing Fan
- School of Pharmacy, The Chinese University of Hong Kong, Hong Kong
| | | | - Raymond S M Wong
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong
| | - Xiaoyu Yan
- School of Pharmacy, The Chinese University of Hong Kong, Hong Kong
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5
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Zingariello M, Martelli F, Verachi P, Bardelli C, Gobbo F, Mazzarini M, Migliaccio AR. Novel targets to cure primary myelofibrosis from studies on Gata1 low mice. IUBMB Life 2019; 72:131-141. [PMID: 31749302 DOI: 10.1002/iub.2198] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 10/24/2019] [Indexed: 01/06/2023]
Abstract
In 2002, we discovered that mice carrying the hypomorphic Gata1low mutation that reduces expression of the transcription factor GATA1 in megakaryocytes (Gata1low mice) develop myelofibrosis, a phenotype that recapitulates the features of primary myelofibrosis (PMF), the most severe of the Philadelphia-negative myeloproliferative neoplasms (MPNs). At that time, this discovery had a great impact on the field because mutations driving the development of PMF had yet to be discovered. Later studies identified that PMF, as the others MPNs, is associated with mutations activating the thrombopoietin/JAK2 axis raising great hope that JAK inhibitors may be effective to treat the disease. Unfortunately, ruxolitinib, the JAK1/2 inhibitor approved by FDA and EMEA for PMF, ameliorates symptoms but does not improve the natural course of the disease, and the cure of PMF is still an unmet clinical need. Although GATA1 is not mutated in PMF, reduced GATA1 content in megakaryocytes as a consequence of ribosomal deficiency is a hallmark of myelofibrosis (both in humans and mouse models) and, in fact, a driving event in the disease. Conversely, mice carrying the hypomorphic Gata1low mutation express an activated TPO/JAK2 pathway and partially respond to JAK inhibitors in a fashion similar to PMF patients (reduction of spleen size but limited improvement of the natural history of the disease). These observations cross-validated Gata1low mice as a bona fide animal model for PMF and prompted the use of this model to identify abnormalities that might be targeted to cure the disease. We will summarize here data generated in Gata1low mice indicating that the TGF-β/P-selectin axis is abnormal in PMF and represents a novel target for its treatment.
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Affiliation(s)
- Maria Zingariello
- Unit of Microscopic and Ultrastructural Anatomy, Department of Medicine, University Campus Bio-Medico, Rome, Italy
| | | | - Paola Verachi
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy
| | - Claudio Bardelli
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy
| | - Francesca Gobbo
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy
| | - Maria Mazzarini
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy
| | - Anna Rita Migliaccio
- Department of Biological and Neurobiological Medicine, University of Bologna, Bologna, Italy.,Myeloproliferative Neoplasms Research Consortium, New York, New York
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6
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Maurer B, Kollmann S, Pickem J, Hoelbl-Kovacic A, Sexl V. STAT5A and STAT5B-Twins with Different Personalities in Hematopoiesis and Leukemia. Cancers (Basel) 2019; 11:E1726. [PMID: 31690038 PMCID: PMC6895831 DOI: 10.3390/cancers11111726] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/25/2019] [Accepted: 11/01/2019] [Indexed: 12/14/2022] Open
Abstract
The transcription factors STAT5A and STAT5B have essential roles in survival and proliferation of hematopoietic cells-which have been considered largely redundant. Mutations of upstream kinases, copy number gains, or activating mutations in STAT5A, or more frequently in STAT5B, cause altered hematopoiesis and cancer. Interfering with their activity by pharmacological intervention is an up-and-coming therapeutic avenue. Precision medicine requests detailed knowledge of STAT5A's and STAT5B's individual functions. Recent evidence highlights the privileged role for STAT5B over STAT5A in normal and malignant hematopoiesis. Here, we provide an overview on their individual functions within the hematopoietic system.
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Affiliation(s)
- Barbara Maurer
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, 1210 Vienna, Austria.
| | - Sebastian Kollmann
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Judith Pickem
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Andrea Hoelbl-Kovacic
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Veronika Sexl
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, 1210 Vienna, Austria
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7
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Mesuraca M, Amodio N, Chiarella E, Scicchitano S, Aloisio A, Codispoti B, Lucchino V, Montalcini Y, Bond HM, Morrone G. Turning Stem Cells Bad: Generation of Clinically Relevant Models of Human Acute Myeloid Leukemia through Gene Delivery- or Genome Editing-Based Approaches. Molecules 2018; 23:E2060. [PMID: 30126100 PMCID: PMC6222541 DOI: 10.3390/molecules23082060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 08/09/2018] [Accepted: 08/14/2018] [Indexed: 02/07/2023] Open
Abstract
Acute myeloid leukemia (AML), the most common acute leukemia in the adult, is believed to arise as a consequence of multiple molecular events that confer on primitive hematopoietic progenitors unlimited self-renewal potential and cause defective differentiation. A number of genetic aberrations, among which a variety of gene fusions, have been implicated in the development of a transformed phenotype through the generation of dysfunctional molecules that disrupt key regulatory mechanisms controlling survival, proliferation, and differentiation in normal stem and progenitor cells. Such genetic aberrations can be recreated experimentally to a large extent, to render normal hematopoietic stem cells "bad", analogous to the leukemic stem cells. Here, we wish to provide a brief outline of the complementary experimental approaches, largely based on gene delivery and more recently on gene editing, employed over the last two decades to gain insights into the molecular mechanisms underlying AML development and progression and on the prospects that their applications offer for the discovery and validation of innovative therapies.
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Affiliation(s)
- Maria Mesuraca
- Laboratory of Molecular Haematopoiesis and Stem Cell Biology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
| | - Nicola Amodio
- Laboratory of Medical Oncology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
| | - Emanuela Chiarella
- Laboratory of Molecular Haematopoiesis and Stem Cell Biology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
| | - Stefania Scicchitano
- Laboratory of Molecular Haematopoiesis and Stem Cell Biology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
| | - Annamaria Aloisio
- Laboratory of Molecular Haematopoiesis and Stem Cell Biology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
| | - Bruna Codispoti
- Tecnologica Research Institute-Marrelli Hospital, 88900 Crotone, Italy.
| | - Valeria Lucchino
- Laboratory of Molecular Haematopoiesis and Stem Cell Biology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany.
| | - Ylenia Montalcini
- Laboratory of Molecular Haematopoiesis and Stem Cell Biology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
| | - Heather M Bond
- Laboratory of Molecular Haematopoiesis and Stem Cell Biology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
| | - Giovanni Morrone
- Laboratory of Molecular Haematopoiesis and Stem Cell Biology, Department of Experimental and Clinical Medicine, University Magna Græcia, 88100 Catanzaro, Italy.
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8
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Kollmann K, Warsch W, Gonzalez-Arias C, Nice FL, Avezov E, Milburn J, Li J, Dimitropoulou D, Biddie S, Wang M, Poynton E, Colzani M, Tijssen MR, Anand S, McDermott U, Huntly B, Green T. A novel signalling screen demonstrates that CALR mutations activate essential MAPK signalling and facilitate megakaryocyte differentiation. Leukemia 2017; 31:934-944. [PMID: 27740635 PMCID: PMC5383931 DOI: 10.1038/leu.2016.280] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 08/18/2016] [Accepted: 08/24/2016] [Indexed: 12/15/2022]
Abstract
Most myeloproliferative neoplasm (MPN) patients lacking JAK2 mutations harbour somatic CALR mutations that are thought to activate cytokine signalling although the mechanism is unclear. To identify kinases important for survival of CALR-mutant cells, we developed a novel strategy (KISMET) that utilizes the full range of kinase selectivity data available from each inhibitor and thus takes advantage of off-target noise that limits conventional small-interfering RNA or inhibitor screens. KISMET successfully identified known essential kinases in haematopoietic and non-haematopoietic cell lines and identified the mitogen activated protein kinase (MAPK) pathway as required for growth of the CALR-mutated MARIMO cells. Expression of mutant CALR in murine or human haematopoietic cell lines was accompanied by myeloproliferative leukemia protein (MPL)-dependent activation of MAPK signalling, and MPN patients with CALR mutations showed increased MAPK activity in CD34 cells, platelets and megakaryocytes. Although CALR mutations resulted in protein instability and proteosomal degradation, mutant CALR was able to enhance megakaryopoiesis and pro-platelet production from human CD34+ progenitors. These data link aberrant MAPK activation to the MPN phenotype and identify it as a potential therapeutic target in CALR-mutant positive MPNs.
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Affiliation(s)
- K Kollmann
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - W Warsch
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - C Gonzalez-Arias
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - F L Nice
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - E Avezov
- Cambridge Institute for Medical Research, Wellcome Trust MRC Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Cambridge, UK
| | - J Milburn
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - J Li
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - D Dimitropoulou
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - S Biddie
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - M Wang
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - E Poynton
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - M Colzani
- Department of Haematology, University of Cambridge, and National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
| | - M R Tijssen
- Department of Haematology, University of Cambridge, and National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
| | - S Anand
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - U McDermott
- Cancer Genome Project, Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridgeshire, UK
| | - B Huntly
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - T Green
- Cambridge Institute for Medical Research and Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
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9
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Ward D, Carter D, Homer M, Marucci L, Gampel A. Mathematical modeling reveals differential effects of erythropoietin on proliferation and lineage commitment of human hematopoietic progenitors in early erythroid culture. Haematologica 2015; 101:286-96. [PMID: 26589912 DOI: 10.3324/haematol.2015.133637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/18/2015] [Indexed: 02/06/2023] Open
Abstract
Erythropoietin is essential for the production of mature erythroid cells, promoting both proliferation and survival. Whether erythropoietin and other cytokines can influence lineage commitment of hematopoietic stem and progenitor cells is of significant interest. To study lineage restriction of the common myeloid progenitor to the megakaryocyte/erythroid progenitor of peripheral blood CD34(+) cells, we have shown that the cell surface protein CD36 identifies the earliest lineage restricted megakaryocyte/erythroid progenitor. Using this marker and carboxyfluorescein succinimidyl ester to track cell divisions in vitro, we have developed a mathematical model that accurately predicts population dynamics of erythroid culture. Parameters derived from the modeling of cultures without added erythropoietin indicate that the rate of lineage restriction is not affected by erythropoietin. By contrast, megakaryocyte/erythroid progenitor proliferation is sensitive to erythropoietin from the time that CD36 first appears at the cell surface. These results shed new light on the role of erythropoietin in erythropoiesis and provide a powerful tool for further study of hematopoietic progenitor lineage restriction and erythropoiesis.
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Affiliation(s)
- Daniel Ward
- Department of Engineering Mathematics, Faculty of Engineering, University of Bristol
| | - Deborah Carter
- School of Biochemistry, Faculty of Medical and Veterinary Science, University of Bristol, UK
| | - Martin Homer
- Department of Engineering Mathematics, Faculty of Engineering, University of Bristol
| | - Lucia Marucci
- Department of Engineering Mathematics, Faculty of Engineering, University of Bristol
| | - Alexandra Gampel
- School of Biochemistry, Faculty of Medical and Veterinary Science, University of Bristol, UK
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10
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Zhang L, Tran NT, Su H, Wang R, Lu Y, Tang H, Aoyagi S, Guo A, Khodadadi-Jamayran A, Zhou D, Qian K, Hricik T, Côté J, Han X, Zhou W, Laha S, Abdel-Wahab O, Levine RL, Raffel G, Liu Y, Chen D, Li H, Townes T, Wang H, Deng H, Zheng YG, Leslie C, Luo M, Zhao X. Cross-talk between PRMT1-mediated methylation and ubiquitylation on RBM15 controls RNA splicing. eLife 2015; 4:07938. [PMID: 26575292 PMCID: PMC4775220 DOI: 10.7554/elife.07938] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 11/16/2015] [Indexed: 12/24/2022] Open
Abstract
RBM15, an RNA binding protein, determines cell-fate specification of many tissues including blood. We demonstrate that RBM15 is methylated by protein arginine methyltransferase 1 (PRMT1) at residue R578, leading to its degradation via ubiquitylation by an E3 ligase (CNOT4). Overexpression of PRMT1 in acute megakaryocytic leukemia cell lines blocks megakaryocyte terminal differentiation by downregulation of RBM15 protein level. Restoring RBM15 protein level rescues megakaryocyte terminal differentiation blocked by PRMT1 overexpression. At the molecular level, RBM15 binds to pre-messenger RNA intronic regions of genes important for megakaryopoiesis such as GATA1, RUNX1, TAL1 and c-MPL. Furthermore, preferential binding of RBM15 to specific intronic regions recruits the splicing factor SF3B1 to the same sites for alternative splicing. Therefore, PRMT1 regulates alternative RNA splicing via reducing RBM15 protein concentration. Targeting PRMT1 may be a curative therapy to restore megakaryocyte differentiation for acute megakaryocytic leukemia. DOI:http://dx.doi.org/10.7554/eLife.07938.001 The many different cell types in an adult animal all develop from a single fertilized egg. The development of cells into more specialized cell types is called ‘differentiation’. Proteins and other molecules from both inside and outside of the cells regulate the differentiation process. RNA is a molecule that is similar to DNA, and performs several important roles inside cells. Perhaps most importantly, RNA molecules act as messengers and carry genetic instructions during gene expression. RBM15 is an RNA-binding protein that is found throughout nature, and is involved in a number of developmental processes. Previous research has linked the incorrect control of RBM15 with an increased risk of certain cancers, including megakaryocytic leukemia. However, it is not clear what role RNA-binding proteins such as RBM15 play during differentiation. Now, Zhang, Tran, Su et al. have investigated the role of RBM15 during the development of large cells found in human bone marrow (called megakaryocytes). First, the experiments demonstrated that an enzyme called PRMT1 modifies RBM15. This enzyme adds a chemical mark called a methyl group at a specific site (an arginine amino acid) on the RNA-binding protein. Next, Zhang, Tran, Su et al. showed that the addition of this methyl group earmarks RBM15 for destruction. This means that an increase in PRMT1 levels reduces the amount of RBM15 in cells, while decreases in PRMT1 have the opposite effect. Further experiments showed that RBM15 normally processes the RNA messengers that carry the genetic instructions needed for the differentiation of bone marrow cells. An excess of PRMT1 enzyme leads to a lack of this RNA-binding protein. This in turn interferes with the differentiation process, and can contribute to the development of cancers such as megakaryocytic leukemia. Future work will therefore explore whether targeting PRMT1 with drugs could represent an effective treatment for these kinds of cancers. DOI:http://dx.doi.org/10.7554/eLife.07938.002
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Affiliation(s)
- Li Zhang
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Ngoc-Tung Tran
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Hairui Su
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Rui Wang
- Program of Molecular Pharmacology, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Yuheng Lu
- Computational Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Haiping Tang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Sayura Aoyagi
- Cell Signaling Technology, Inc., Danvers, United States
| | - Ailan Guo
- Cell Signaling Technology, Inc., Danvers, United States
| | - Alireza Khodadadi-Jamayran
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Dewang Zhou
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Kun Qian
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, United States
| | - Todd Hricik
- Human Oncology and Pathogenesis Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Xiaosi Han
- Department of Neurology, Comprehensive Cancer Center, The University of Alabama at Birmingham, Birmingham, United States
| | - Wenping Zhou
- Department of Internal Medicine, Zhengzhou - Henan Cancer Hospital, Zhengzhou, China
| | - Suparna Laha
- Division of Hematology and Oncology, University of Massachusetts Medical School, Worcester, United States
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Ross L Levine
- Human Oncology and Pathogenesis Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Glen Raffel
- Division of Hematology and Oncology, University of Massachusetts Medical School, Worcester, United States
| | - Yanyan Liu
- Department of Internal Medicine, Zhengzhou - Henan Cancer Hospital, Zhengzhou, China
| | - Dongquan Chen
- Division of Preventive Medicine, The University of Alabama at Birmingham, Birmingham, United States
| | - Haitao Li
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Tim Townes
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Hengbin Wang
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
| | - Haiteng Deng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Y George Zheng
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, United States
| | - Christina Leslie
- Computational Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Minkui Luo
- Program of Molecular Pharmacology, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Xinyang Zhao
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, The University of Alabama at Birmingham, Birmingham, United States
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11
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Matsuo Y, Park JH, Miyamoto T, Yamamoto S, Hisada S, Alachkar H, Nakamura Y. TOPK inhibitor induces complete tumor regression in xenograft models of human cancer through inhibition of cytokinesis. Sci Transl Med 2015; 6:259ra145. [PMID: 25338756 DOI: 10.1126/scitranslmed.3010277] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
TOPK (T-lymphokine-activated killer cell-originated protein kinase) is highly and frequently transactivated in various cancer tissues, including lung and triple-negative breast cancers, and plays an indispensable role in the mitosis of cancer cells. We report the development of a potent TOPK inhibitor, OTS964 {(R)-9-(4-(1-(dimethylamino)propan-2-yl)phenyl)-8-hydroxy-6-methylthieno[2,3-c]quinolin-4(5H)-one}, which inhibits TOPK kinase activity with high affinity and selectivity. Similar to the knockdown effect of TOPK small interfering RNAs (siRNAs), this inhibitor causes a cytokinesis defect and the subsequent apoptosis of cancer cells in vitro as well as in xenograft models of human lung cancer. Although administration of the free compound induced hematopoietic adverse reactions (leukocytopenia associated with thrombocytosis), the drug delivered in a liposomal formulation effectively caused complete regression of transplanted tumors without showing any adverse reactions in mice. Our results suggest that the inhibition of TOPK activity may be a viable therapeutic option for the treatment of various human cancers.
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Affiliation(s)
- Yo Matsuo
- OncoTherapy Science Inc., Kawasaki, Kanagawa 213-0012, Japan
| | - Jae-Hyun Park
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | | | - Shinji Yamamoto
- OncoTherapy Science Inc., Kawasaki, Kanagawa 213-0012, Japan
| | - Shoji Hisada
- OncoTherapy Science Inc., Kawasaki, Kanagawa 213-0012, Japan
| | - Houda Alachkar
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Yusuke Nakamura
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA.
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12
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Wang L, Jiang R, Song SD, Hua ZS, Wang JW, Wang YP. Angelica Sinensis Polysaccharide Induces Erythroid Differentiation of Human Chronic Myelogenous Leukemia K562 Cells. Asian Pac J Cancer Prev 2015; 16:3715-21. [DOI: 10.7314/apjcp.2015.16.9.3715] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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13
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JAK2V617F promotes replication fork stalling with disease-restricted impairment of the intra-S checkpoint response. Proc Natl Acad Sci U S A 2014; 111:15190-5. [PMID: 25288776 DOI: 10.1073/pnas.1401873111] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cancers result from the accumulation of genetic lesions, but the cellular consequences of driver mutations remain unclear, especially during the earliest stages of malignancy. The V617F mutation in the JAK2 non-receptor tyrosine kinase (JAK2V617F) is present as an early somatic event in most patients with myeloproliferative neoplasms (MPNs), and the study of these chronic myeloid malignancies provides an experimentally tractable approach to understanding early tumorigenesis. Introduction of exogenous JAK2V617F impairs replication fork progression and is associated with activation of the intra-S checkpoint, with both effects mediated by phosphatidylinositide 3-kinase (PI3K) signaling. Analysis of clonally derived JAK2V617F-positive erythroblasts from MPN patients also demonstrated impaired replication fork progression accompanied by increased levels of replication protein A (RPA)-containing foci. However, the associated intra-S checkpoint response was impaired in erythroblasts from polycythemia vera (PV) patients, but not in those from essential thrombocythemia (ET) patients. Moreover, inhibition of p53 in PV erythroblasts resulted in more gamma-H2Ax (γ-H2Ax)-marked double-stranded breaks compared with in like-treated ET erythroblasts, suggesting the defective intra-S checkpoint function seen in PV increases DNA damage in the context of attenuated p53 signaling. These results demonstrate oncogene-induced impairment of replication fork progression in primary cells from MPN patients, reveal unexpected disease-restricted differences in activation of the intra-S checkpoint, and have potential implications for the clonal evolution of malignancies.
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14
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Staerk J, Constantinescu SN. The JAK-STAT pathway and hematopoietic stem cells from the JAK2 V617F perspective. JAKSTAT 2014; 1:184-90. [PMID: 24058768 PMCID: PMC3670242 DOI: 10.4161/jkst.22071] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 07/25/2012] [Accepted: 09/04/2012] [Indexed: 12/30/2022] Open
Abstract
Janus kinases (JAKs) are non-receptor tyrosine kinases essential for activation of signaling mediated by cytokine receptors that lack catalytic activity, including receptors for erythropoietin, thrombopoietin, most interleukins and interferon. Upon hormone binding, JAKs phosphorylate tyrosine residues in the receptor cytoplasmic domains and in JAKs themselves leading to recruitment and activation of downstream signaling proteins such as signal transducer and activator of transcription (STAT). The JAK-STAT pathway is important for functional hematopoiesis and several activating mutations in JAK proteins have recently been described as underlying cause of blood disorders. One of the best studied examples is the JAK2 V617F mutant which is found in 95% of polycythemia vera patients and 50% of patients suffering from essential thrombocythemia and primary myelofibrosis. Much effort has been made to understand how the JAK2 V617F affects hematopoietic stem cell (HSC) renewal and lineage differentiation, since convincing evidence has been provided to support the notion that the mutation is acquired at the HSC level. We discuss several in vivo models that support contrary conclusions with respect to the advantage given to HSCs by JAK2 V617F. Moreover, we provide the current knowledge about STAT5 activation and its link to HSC expansion as well as amplification of the erythroid compartment. Evidence for both JAK2 V617F mutated HSCs exhibiting skewed differentiation potential and for amplification occurring after erythroid commitment has been provided, and we will discuss whether this evidence is relevant for the disease.
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Affiliation(s)
- Judith Staerk
- Stem Cell Group; Nordic EMBL Partnership; Centre for Molecular Medicine Norway (NCMM); University of Oslo; Oslo, Norway ; Department of Hematology; Oslo University Hospital; Oslo, Norway
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15
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Abstract
The molecular pathways that regulate megakaryocyte production have historically been identified through multiple candidate gene approaches. Several transcription factors critical for generating megakaryocytes were identified by promoter analysis of megakaryocyte-specific genes, and their biological roles then verified by gene knockout studies; for example, GATA-1, NF-E2, and RUNX1 were identified in this way. In contrast, other transcription factors important for megakaryopoiesis were discovered through a systems approach; for example, c-Myb was found to be critical for the erythroid versus megakaryocyte lineage decision by genome-wide loss-of-function studies. The regulation of the levels of these transcription factors is, for the most part, cell intrinsic, although that assumption has recently been challenged. Epigenetics also impacts megakaryocyte gene expression, mediated by histone acetylation and methylation. Several cytokines have been identified to regulate megakaryocyte survival, proliferation, and differentiation, most prominent of which is thrombopoietin. Upon binding to its receptor, the product of the c-Mpl proto-oncogene, thrombopoietin induces a conformational change that activates a number of secondary messengers that promote cell survival, proliferation, and differentiation, and down-modulate receptor signaling. Among the best studied are the signal transducers and activators of transcription (STAT) proteins; phosphoinositol-3-kinase; mitogen-activated protein kinases; the phosphatases PTEN, SHP1, SHP2, and SHIP1; and the suppressors of cytokine signaling (SOCS) proteins. Additional signals activated by these secondary mediators include mammalian target of rapamycin; β(beta)-catenin; the G proteins Rac1, Rho, and CDC42; several transcription factors, including hypoxia-inducible factor 1α(alpha), the homeobox-containing proteins HOXB4 and HOXA9, and a number of signaling mediators that are reduced, including glycogen synthase kinase 3α(alpha) and the FOXO3 family of forkhead proteins. More recently, systematic interrogation of several aspects of megakaryocyte formation have been conducted, employing genomics, proteomics, and chromatin immunoprecipitation (ChIP) analyses, among others, and have yielded many previously unappreciated signaling mechanisms that regulate megakaryocyte lineage determination, proliferation, and differentiation. This chapter focuses on these pathways in normal and neoplastic megakaryopoiesis, and suggests areas that are ripe for further study.
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16
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Hirata S, Takayama N, Jono-Ohnishi R, Endo H, Nakamura S, Dohda T, Nishi M, Hamazaki Y, Ishii EI, Kaneko S, Otsu M, Nakauchi H, Kunishima S, Eto K. Congenital amegakaryocytic thrombocytopenia iPS cells exhibit defective MPL-mediated signaling. J Clin Invest 2013; 123:3802-14. [PMID: 23908116 DOI: 10.1172/jci64721] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 05/30/2013] [Indexed: 12/20/2022] Open
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is caused by the loss of thrombopoietin receptor-mediated (MPL-mediated) signaling, which causes severe pancytopenia leading to bone marrow failure with onset of thrombocytopenia and anemia prior to leukopenia. Because Mpl(-/-) mice do not exhibit the human disease phenotype, we used an in vitro disease tracing system with induced pluripotent stem cells (iPSCs) derived from a CAMT patient (CAMT iPSCs) and normal iPSCs to investigate the role of MPL signaling in hematopoiesis. We found that MPL signaling is essential for maintenance of the CD34+ multipotent hematopoietic progenitor (MPP) population and development of the CD41+GPA+ megakaryocyte-erythrocyte progenitor (MEP) population, and its role in the fate decision leading differentiation toward megakaryopoiesis or erythropoiesis differs considerably between normal and CAMT cells. Surprisingly, complimentary transduction of MPL into normal or CAMT iPSCs using a retroviral vector showed that MPL overexpression promoted erythropoiesis in normal CD34+ hematopoietic progenitor cells (HPCs), but impaired erythropoiesis and increased aberrant megakaryocyte production in CAMT iPSC-derived CD34+ HPCs, reflecting a difference in the expression of the transcription factor FLI1. These results demonstrate that impaired transcriptional regulation of the MPL signaling that normally governs megakaryopoiesis and erythropoiesis underlies CAMT.
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Affiliation(s)
- Shinji Hirata
- Clinical Application Department, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
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Tibes R, Bogenberger JM, Geyer HL, Mesa RA. JAK2 inhibitors in the treatment of myeloproliferative neoplasms. Expert Opin Investig Drugs 2012; 21:1755-74. [PMID: 22991927 DOI: 10.1517/13543784.2012.721352] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Dysregulation of JAK-STAT signaling is a pathogenetic hallmark of myeloproliferative neoplasms (MPNs) arising from several distinct molecular aberrations, including mutations in JAK2, the thrombopoietin receptor (MPL), mutations in negative regulators of JAK-STAT signaling, such as lymphocyte-specific adapter protein (SH2B3), and epigenetic dysregulation as seen with Suppressor of Cytokine Signaling (SOCS) proteins. In addition, growth factor/cytokine stimulatory events activate JAK-STAT signaling independent of mutations. AREAS COVERED The various mutations and molecular events activating JAK-STAT signaling in MPNs are reviewed. Detailed inhibitory kinase profiles of the currently developed JAK inhibitors are presented. Clinical trial results for currently developed JAK targeting agents are comprehensively summarized. The limitations of JAK-STAT targeting in MPNs, as well as potential rational combination therapies with JAK2 inhibitors, are discussed. EXPERT OPINION Aberrant JAK-STAT signaling is an underlying theme in the pathogenesis of MPNs. While JAK2 inhibitors are active in JAK2V617F and wild-type JAK2 MPNs, JAK2V617F mutation-specific or JAK2-selective inhibitors may possess unique clinical attributes. Complimentary targeting of parallel pathways operating in MPNs may offer novel therapeutic approaches in combination with JAK inhibition. Understanding the intricacies of JAK-STAT pathway activation, including growth factor/cytokine-driven signaling, will open new avenues for therapeutic intervention at known and novel molecular vulnerabilities of MPNs.
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Affiliation(s)
- Raoul Tibes
- Mayo Clinic, Hematology, 200 First Street SW, Rochester, MN 55905, USA.
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18
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Lorenzo PI, Brendeford EM, Gilfillan S, Gavrilov AA, Leedsak M, Razin SV, Eskeland R, Sæther T, Gabrielsen OS. Identification of c-Myb Target Genes in K562 Cells Reveals a Role for c-Myb as a Master Regulator. Genes Cancer 2012; 2:805-17. [PMID: 22393465 DOI: 10.1177/1947601911428224] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 10/08/2011] [Indexed: 11/17/2022] Open
Abstract
The c-Myb transcription factor is an important regulator of hematopoietic cell development. c-Myb is expressed in immature hematopoietic cells and plays a direct role in lineage fate selection, cell cycle progression, and differentiation of myeloid as well as B- and T-lymphoid progenitor cells. As a DNA-binding transcription factor, c-Myb regulates specific gene programs through activation of target genes. Still, our understanding of these programs is incomplete. Here, we report a set of novel c-Myb target genes, identified using a combined approach: specific c-Myb knockdown by 2 different siRNAs and subsequent global expression profiling, combined with the confirmation of direct binding of c-Myb to the target promoters by ChIP assays. The combination of these 2 approaches, as well as additional validation such as cloning and testing the promoters in reporter assays, confirmed that MYADM, LMO2, GATA2, STAT5A, and IKZF1 are target genes of c-Myb. Additional studies, using chromosome conformation capture, demonstrated that c-Myb target genes may directly interact with each other, indicating that these genes may be coordinately regulated. Of the 5 novel target genes identified, 3 are transcription factors, and one is a transcriptional co-regulator, supporting a role of c-Myb as a master regulator controlling the expression of other transcriptional regulators in the hematopoietic system.
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Tounkara FK, Dumont N, Fournier S, Boyer L, Nadeau P, Pineault N. Mild hyperthermia promotes and accelerates development and maturation of erythroid cells. Stem Cells Dev 2012; 21:3197-208. [PMID: 22564002 DOI: 10.1089/scd.2012.0112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hyperthermia treatment has at times been associated with increased platelet levels in humans. The heat shock protein HSP70, which can be induced by hyperthermia in megakaryocytes and erythrocytes, was recently shown to protect GATA-1 from degradation and to be required for erythroid differentiation. Based on these findings, we hypothesize that mild hyperthermia (MH), such as fever (39°C), could impact the differentiation of hematopoietic progenitors into erythrocytes and their subsequent maturation. Cell growth and erythroid differentiation increased dramatically in cord blood CD34(+) cell cultures incubated under MH. Erythroid maturation was also strongly promoted, which resulted in an increased proportion of hemoglobinized and enucleated erythroids. The rise in erythroid development was traced to a strong synergistic activity between MH and erythropoietin (EPO). The molecular basis for this potent synergy appears to originate from the capacity of MH to increase the basal activation of several signaling molecules downstream of the EPO receptor and the transcriptional activity of GATA-1. Moreover, the potent impact of MH on erythroid development was found be dependent on increased intracellular levels of reactive oxygen species. Thus, fever-like temperatures can promote the differentiation of progenitors along the erythroid lineage and accelerate their maturation through normal regulatory circuitry.
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Increased basal intracellular signaling patterns do not correlate with JAK2 genotype in human myeloproliferative neoplasms. Blood 2011; 118:1610-21. [DOI: 10.1182/blood-2011-02-335042] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Abstract
Myeloproliferative neoplasms (MPNs) are associated with recurrent activating mutations of signaling proteins such as Janus kinase 2 (JAK2). However, the actual downstream signaling events and how these alter myeloid homeostasis are poorly understood. We developed an assay to measure basal levels of phosphorylated signaling intermediates by flow cytometry during myeloid differentiation in MPN patients. Our study provides the first systematic demonstration of specific signaling events and their comparison with disease phenotype and JAK2 mutation status. We demonstrate increased basal signaling in MPN patients, which occurs in both early and later stages of myeloid differentiation. In addition, the pattern of signaling is not correlated with JAK2 mutation status and signaling intensity is poorly correlated with mutant JAK2 allele burden. In contrast, signaling differences are detected between different MPN disease phenotypes. Finally, we demonstrate that signaling can be inhibited by a JAK2-selective small molecule, but that this inhibition is not JAK2 V617F specific, because MPN patients with mutant JAK2, wild-type JAK2, and control patients were inhibited to a similar degree. Our data suggest that, in addition to JAK2 mutations, other factors contribute significantly to the MPN phenotype, results that are relevant to both the pathogenesis and therapy of MPN.
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21
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Division of labor by dual feedback regulators controls JAK2/STAT5 signaling over broad ligand range. Mol Syst Biol 2011; 7:516. [PMID: 21772264 PMCID: PMC3159971 DOI: 10.1038/msb.2011.50] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 06/10/2011] [Indexed: 02/06/2023] Open
Abstract
Cellular signal transduction is governed by multiple feedback mechanisms to elicit robust cellular decisions. The specific contributions of individual feedback regulators, however, remain unclear. Based on extensive time-resolved data sets in primary erythroid progenitor cells, we established a dynamic pathway model to dissect the roles of the two transcriptional negative feedback regulators of the suppressor of cytokine signaling (SOCS) family, CIS and SOCS3, in JAK2/STAT5 signaling. Facilitated by the model, we calculated the STAT5 response for experimentally unobservable Epo concentrations and provide a quantitative link between cell survival and the integrated response of STAT5 in the nucleus. Model predictions show that the two feedbacks CIS and SOCS3 are most effective at different ligand concentration ranges due to their distinct inhibitory mechanisms. This divided function of dual feedback regulation enables control of STAT5 responses for Epo concentrations that can vary 1000-fold in vivo. Our modeling approach reveals dose-dependent feedback control as key property to regulate STAT5-mediated survival decisions over a broad range of ligand concentrations.
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22
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van de Laar L, van den Bosch A, Wierenga ATJ, Janssen HLA, Coffer PJ, Woltman AM. Tight Control of STAT5 Activity Determines Human CD34-Derived Interstitial Dendritic Cell and Langerhans Cell Development. THE JOURNAL OF IMMUNOLOGY 2011; 186:7016-24. [DOI: 10.4049/jimmunol.1003977] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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23
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Chen E, Beer PA, Godfrey AL, Ortmann CA, Li J, Costa-Pereira AP, Ingle CE, Dermitzakis ET, Campbell PJ, Green AR. Distinct clinical phenotypes associated with JAK2V617F reflect differential STAT1 signaling. Cancer Cell 2010; 18:524-35. [PMID: 21074499 PMCID: PMC2996868 DOI: 10.1016/j.ccr.2010.10.013] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 10/07/2010] [Accepted: 10/13/2010] [Indexed: 01/17/2023]
Abstract
The JAK2V617F mutation is associated with distinct myeloproliferative neoplasms, including polycythemia vera (PV) and essential thrombocythemia (ET), but it remains unclear how it generates disparate disorders. By comparing clonally-derived mutant and wild-type cells from individual patients, we demonstrate that the transcriptional consequences of JAK2V617F are subtle, and that JAK2V617F-heterozygous erythroid cells from ET and PV patients exhibit differential interferon signaling and STAT1 phosphorylation. Increased STAT1 activity in normal CD34-positive progenitors produces an ET-like phenotype, whereas downregulation of STAT1 activity in JAK2V617F-heterozygous ET progenitors produces a PV-like phenotype. Our results illustrate the power of clonal analysis, indicate that the consequences of JAK2V617F reflect a balance between STAT5 and STAT1 activation and are relevant for other neoplasms associated with signaling pathway mutations.
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Affiliation(s)
- Edwin Chen
- Cambridge Institute for Medical Research and Department of Haematology, University of Cambridge, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Philip A Beer
- Cambridge Institute for Medical Research and Department of Haematology, University of Cambridge, Hills Road, Cambridge, CB2 0XY, United Kingdom
- Department of Haematology, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0XY
| | - Anna L Godfrey
- Cambridge Institute for Medical Research and Department of Haematology, University of Cambridge, Hills Road, Cambridge, CB2 0XY, United Kingdom
- Department of Haematology, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0XY
| | - Christina A Ortmann
- Cambridge Institute for Medical Research and Department of Haematology, University of Cambridge, Hills Road, Cambridge, CB2 0XY, United Kingdom
- Department of Haematology, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0XY
| | - Juan Li
- Cambridge Institute for Medical Research and Department of Haematology, University of Cambridge, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Ana P. Costa-Pereira
- Imperial College London, Department of Surgery and Cancer, Hammersmith Hospital, London W12 0NN
| | | | | | - Peter J Campbell
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA
| | - Anthony R. Green
- Cambridge Institute for Medical Research and Department of Haematology, University of Cambridge, Hills Road, Cambridge, CB2 0XY, United Kingdom
- Department of Haematology, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0XY
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Yu JH, Zhu BM, Wickre M, Riedlinger G, Chen W, Hosui A, Robinson GW, Hennighausen L. The transcription factors signal transducer and activator of transcription 5A (STAT5A) and STAT5B negatively regulate cell proliferation through the activation of cyclin-dependent kinase inhibitor 2b (Cdkn2b) and Cdkn1a expression. Hepatology 2010; 52:1808-18. [PMID: 21038417 PMCID: PMC3152209 DOI: 10.1002/hep.23882] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Although the cytokine-inducible transcription factor signal transducer and activator of transcription 5 (STAT5) promotes proliferation of a wide range of cell types, there are cell-specific and context-specific cases in which loss of STAT5 results in enhanced cell proliferation. Here, we report that loss of STAT5 from mouse embryonic fibroblasts (MEFs) leads to enhanced proliferation, which was linked to reduced levels of the cell cycle inhibitors p15(INK4B) and p21(CIP1). We further demonstrate that growth hormone, through the transcription factor STAT5, enhances expression of the Cdkn2b (cyclin-dependent kinase inhibitor 2B) gene and that STAT5A binds to interferon-gamma-activated sequence sites within the promoter. We recently demonstrated that ablation of STAT5 from liver results in hepatocellular carcinoma upon CCl₄ treatment. We now establish that STAT5, like in MEFs, activates expression of the Cdkn2b gene in liver tissue. Loss of STAT5 led to diminished p15(INK4B) and increased hepatocyte proliferation. CONCLUSION This study for the first time demonstrates that cytokines, through STAT5, induce the expression of a key cell cycle inhibitor. These experiments therefore shed mechanistic light on the context-specific role of STAT5 as tumor suppressor.
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Affiliation(s)
- Ji Hoon Yu
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bing-Mei Zhu
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark Wickre
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gregory Riedlinger
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Weiping Chen
- Genomics Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Atsushi Hosui
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Gertraud W. Robinson
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lothar Hennighausen
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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25
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Inducible Fli-1 gene deletion in adult mice modifies several myeloid lineage commitment decisions and accelerates proliferation arrest and terminal erythrocytic differentiation. Blood 2010; 116:4795-805. [PMID: 20733157 DOI: 10.1182/blood-2010-02-270405] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study investigated the role of the ETS transcription factor Fli-1 in adult myelopoiesis using new transgenic mice allowing inducible Fli-1 gene deletion. Fli-1 deletion in adult induced mild thrombocytopenia associated with a drastic decrease in large mature megakaryocytes number. Bone marrow bipotent megakaryocytic-erythrocytic progenitors (MEPs) increased by 50% without increase in erythrocytic and megakaryocytic common myeloid progenitor progeny, suggesting increased production from upstream stem cells. These MEPs were almost unable to generate pure colonies containing large mature megakaryocytes, but generated the same total number of colonies mainly identifiable as erythroid colonies containing a reduced number of more differentiated cells. Cytological and fluorescence-activated cell sorting analyses of MEP progeny in semisolid and liquid cultures confirmed the drastic decrease in large mature megakaryocytes but revealed a surprisingly modest (50%) reduction of CD41-positive cells indicating the persistence of a megakaryocytic commitment potential. Symmetrical increase and decrease of monocytic and granulocytic progenitors were also observed in the progeny of purified granulocytic-monocytic progenitors and common myeloid progenitors. In summary, this study indicates that Fli-1 controls several lineages commitment decisions at the stem cell, MEP, and granulocytic-monocytic progenitor levels, stimulates the proliferation of committed erythrocytic progenitors at the expense of their differentiation, and is a major regulator of late stages of megakaryocytic differentiation.
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Vignudelli T, Selmi T, Martello A, Parenti S, Grande A, Gemelli C, Zanocco-Marani T, Ferrari S. ZFP36L1 negatively regulates erythroid differentiation of CD34+ hematopoietic stem cells by interfering with the Stat5b pathway. Mol Biol Cell 2010; 21:3340-51. [PMID: 20702587 PMCID: PMC2947470 DOI: 10.1091/mbc.e10-01-0040] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ZFP36L1 is a member of a family of CCCH tandem zinc finger proteins (TTP family) able to bind to AU-rich elements in the 3'-untranslated region of mRNAs, thereby triggering their degradation. The present study suggests that such mechanism is used during hematopoiesis to regulate differentiation by posttranscriptionally modulating the expression of specific target genes. In particular, it demonstrates that ZFP36L1 negatively regulates erythroid differentiation by directly binding the 3' untranslated region of Stat5b encoding mRNA. Stat5b down-regulation obtained by ZFP36L1 overexpression results, in human hematopoietic progenitors, in a drastic decrease of erythroid colonies formation. These observations have been confirmed by silencing experiments targeting Stat5b and by treating hematopoietic stem/progenitor cells with drugs able to induce ZFP36L1 expression. Moreover, this study shows that different members of ZFP36L1 family act redundantly, because cooverexpression of ZFP36L1 and family member ZFP36 determines a cumulative effect on Stat5b down-regulation. This work describes a mechanism underlying ZFP36L1 capability to regulate hematopoietic differentiation and suggests a new target for the therapy of hematopoietic diseases involving Stat5b/JAK2 pathway, such as chronic myeloproliferative disorders.
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Affiliation(s)
- Tatiana Vignudelli
- Università di Modena e Reggio Emilia, Dipartimento di Scienze Biomediche, Sezione di Chimica Biologica, 41100, Modena, Italy
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Dynamics of progenitor cells and ventricular assist device intervention. J Cardiovasc Transl Res 2010; 3:147-52. [PMID: 20560028 DOI: 10.1007/s12265-009-9141-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 10/05/2009] [Indexed: 10/20/2022]
Abstract
Experimental and clinical evidence suggests that a heterogeneous group of bone-marrow-derived circulating progenitor cells, with variations in phenotype and function, provide an endogenous repair mechanism, contributing to vascular healing and remodeling under physiological and pathological conditions, such as cancer, atherosclerosis, myocardial infarction, and end-stage heart failure. Implantation of ventricular assist devices (VADs) for circulatory support is indicated in selected patients with end-stage heart failure as a bridge to heart transplantation, however seldom; improvement of ventricular contractility has been well documented with prolonged cardiac unloading. The current review summarizes recent findings from in vitro and in vivo studies, focusing on the biological features and the possible role of progenitor cells in the transient myocardial recovery, occasionally seen after VAD implantation, and speculates on their clinical utilities for the treatment of the failing human heart.
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Down-regulation of GATA1 uncouples STAT5-induced erythroid differentiation from stem/progenitor cell proliferation. Blood 2010; 115:4367-76. [DOI: 10.1182/blood-2009-10-250894] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Previously, we have shown that overexpression of an activated mutant of signal transducer and activator of transcription-5 (STAT5) induces erythropoiesis, impaired myelopoiesis, and an increase in long-term proliferation of human hematopoietic stem/progenitor cells. Because GATA1 is a key transcription factor involved in erythropoiesis, the involvement of GATA1 in STAT5-induced phenotypes was studied by shRNA-mediated knockdown of GATA1. CD34+ cord blood cells were double transduced with a conditionally active STAT5 mutant and a lentiviral vector expressing a short hairpin against GATA1. Erythropoiesis was completely abolished in the absence of GATA1, indicating that STAT5-induced erythropoiesis is GATA1-dependent. Furthermore, the impaired myelopoiesis in STAT5-transduced cells was restored by GATA1 knockdown. Interestingly, early cobblestone formation was only modestly affected, and long-term growth of STAT5-positive cells was increased in the absence of GATA1, whereby high progenitor numbers were maintained. Thus, GATA1 down-regulation allowed the dissection of STAT5-induced differentiation phenotypes from the effects on long-term expansion of stem/progenitor cells. Gene expression profiling allowed the identification of GATA1-dependent and GATA1-independent STAT5 target genes, and these studies revealed that several proliferation-related genes were up-regulated by STAT5 independent of GATA1, whereas several erythroid differentiation-related genes were found to be GATA1 as well as STAT5 dependent.
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Auto-SCT induces a phenotypic shift from CMP to GMP progenitors, reduces clonogenic potential and enhances in vitro and in vivo cycling activity defined by 18F-FLT PET scanning. Bone Marrow Transplant 2010; 46:110-5. [DOI: 10.1038/bmt.2010.75] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Harrison C. Rethinking disease definitions and therapeutic strategies in essential thrombocythemia and polycythemia vera. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2010; 2010:129-134. [PMID: 21239782 DOI: 10.1182/asheducation-2010.1.129] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The seminal discovery of the JAK2V617F mutation, which is highly prevalent in Philadelphia-negative myeloproliferative disorders, now renamed neoplasms, triggered an almost unprecedented explosion of interest and data in the field. Descriptions of additional mutations in exon 12 of JAK2, at position 515 in MPL, and a number of other mutations at low frequency followed these discoveries. These advances in our understanding of molecular pathogenesis of these conditions coincided with the publication of results from two major clinical studies, ECLAP and PT-1, which contributed important clinical insights and facilitated significant correlative data collection. This article, focusing mainly upon essential thrombocythemia and polycythemia vera, reviews four major themes: the impact upon classification of these disorders considering a radical review of current terminology, and then three areas pertinent to clinical management: the indications for cytoreductive therapy in which the key targets are to reduce thrombohemorrhagic complications, relieve disease-related symptoms, and minimize the risk of transformation to secondary myeloid malignancy such as myelodysplasia, leukemia, and secondary myelofibrosis; and second reviewing current and, last, future therapeutic options, in particular interferon and JAK2 inhibitors.
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Affiliation(s)
- Claire Harrison
- Guy's and St. Thomas' National Health Service Foundation Trust, London, United Kingdom.
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STAT5 requires the N-domain for suppression of miR15/16, induction of bcl-2, and survival signaling in myeloproliferative disease. Blood 2009; 115:1416-24. [PMID: 20008792 DOI: 10.1182/blood-2009-07-234963] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Phosphorylated signal transducer and activator of transcription 5 (STAT5) is a biomarker and potential molecular target for hematologic malignancies. We have shown previously that lethal myeloproliferative disease (MPD) in mice mediated by persistently activated STAT5 (STAT5a(S711F)) requires the N-domain, but the mechanism was not defined. We now demonstrate by retrovirally complementing STAT5ab(null/null) primary mast cells that relative to wild-type STAT5a, STAT5a lacking the N-domain (STAT5aDeltaN) ineffectively protected against cytokine withdrawal-induced cell death. Both STAT5a and STAT5aDeltaN bound to a site in the bcl-2 gene and both bound near the microRNA 15b/16 cluster. However, only STAT5a could effectively induce bcl-2 mRNA and reciprocally suppress miR15b/16 leading to maintained bcl-2 protein levels. After retroviral complementation of STAT5ab(null/null) fetal liver cells and transplantation, persistently active STAT5a(S711F) lacking the N-domain (STAT5aDeltaN(S711F)) was insufficient to protect c-Kit(+)Lin(-)Sca-1(+) (KLS) cells from apoptosis and unable to induce bcl-2 expression, whereas STAT5a(S711F) caused robust KLS cell expansion, induction of bcl-2, and lethal MPD. Severe attenuation of MPD by STAT5aDeltaN(S711F) was reversed by H2k/bcl-2 transgenic expression. Overall, these studies define N-domain-dependent survival signaling as an Achilles heel of persistent STAT5 activation and highlight the potential therapeutic importance of targeting STAT5 N-domain-mediated regulation of bcl-2 family members.
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Single-cell STAT5 signal transduction profiling in normal and leukemic stem and progenitor cell populations reveals highly distinct cytokine responses. PLoS One 2009; 4:e7989. [PMID: 19956772 PMCID: PMC2776352 DOI: 10.1371/journal.pone.0007989] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 10/30/2009] [Indexed: 01/17/2023] Open
Abstract
Background Signal Transducer and Activator of Transcription 5 (STAT5) plays critical roles in normal and leukemic hematopoiesis. However, the manner in which STAT5 responds to early-acting and lineage-restricted cytokines, particularly in leukemic stem/progenitor cells, is largely unknown. Methodology/Principal Findings We optimized a multiparametric flow cytometry protocol to analyze STAT5 phosphorylation upon cytokine stimulation in stem and progenitor cell compartments at a single-cell level. In normal cord blood (CB) cells, STAT5 phosphorylation was efficiently induced by TPO, IL-3 and GM-CSF within CD34+CD38− hematopoietic stem cells (HSCs). EPO- and SCF-induced STAT5 phosphorylation was largely restricted to the megakaryocyte-erythroid progenitor (MEP) compartment, while G-CSF as well IL-3 and GM-CSF were most efficient in inducing STAT5 phosphorylation in the myeloid progenitor compartments. Strikingly, mobilized adult peripheral blood (PB) CD34+ cells responded much less efficiently to cytokine-induced STAT5 activation, with the exception of TPO. In leukemic stem and progenitor cells, highly distinct cytokine responses were observed, differing significantly from their normal counterparts. These responses could not be predicted by the expression level of cytokine receptors. Also, heterogeneity existed in cytokine requirements for long-term expansion of AML CD34+ cells on stroma. Conclusions/Significance In conclusion, our optimized multiparametric flow cytometry protocols allow the analysis of signal transduction at the single cell level in normal and leukemic stem and progenitor cells. Our study demonstrates highly distinctive cytokine responses in STAT5 phosphorylation in both normal and leukemic stem/progenitor cells.
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Mazharian A, Watson SP, Séverin S. Critical role for ERK1/2 in bone marrow and fetal liver-derived primary megakaryocyte differentiation, motility, and proplatelet formation. Exp Hematol 2009; 37:1238-1249.e5. [PMID: 19619605 PMCID: PMC2755112 DOI: 10.1016/j.exphem.2009.07.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 07/01/2009] [Accepted: 07/07/2009] [Indexed: 12/12/2022]
Abstract
Objective Megakaryopoiesis and platelet formation is a multistep process through which hematopoietic progenitor cells develop into mature megakaryocytes (MKs) and form proplatelets. The present study investigates the regulation of different steps of megakaryopoiesis (i.e., differentiation, migration, and proplatelet formation) by extracellar signal-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK) in two models of primary murine MKs derived from bone marrow (BM) cells and fetal liver (FL) cells. Materials and Methods A preparation of MKs was generated from BM obtained from femora and tibiae of C57BL6 mice. FL-derived MKs were obtained from the liver of mouse fetuses aged 13 to 15 days. Results For both cell populations, activation of MEK-ERK1/2 pathway by thrombopoietin was found to have a critical role in MK differentiation, regulating polyploidy and surface expression of CD34, GPIIb, and GPIb. The MEK-ERK1/2 pathway plays a major role in migration of BM-derived MKs toward a stromal-cell−derived factor 1α (SDF1α) gradient, whereas unexpectedly, FL-derived cells fail to migrate in response to the chemokine due to negligible expression of its receptor, CXCR4. The MEK-ERK1/2 pathway also plays a critical role in the generation of proplatelets. In contrast, p38MAPK pathway was not involved in any of these processes. Conclusion This report demonstrates a critical role of MEK-ERK1/2 pathway in MK differentiation, motility, and proplatelet formation. This study highlights several differences between BM- and FL-derived MKs, which are discussed.
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Affiliation(s)
| | | | - Sonia Séverin
- Offprint requests to: Sonia Séverin, Ph.D., Centre for Cardiovascular Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Wolfson Drive, Edgbaston, Birmingham, B15 2TT, UK
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Fuhler GM, Tyl MR, Olthof SGM, Lyndsay Drayer A, Blom N, Vellenga E. Distinct roles of the mTOR components Rictor and Raptor in MO7e megakaryocytic cells. Eur J Haematol 2009; 83:235-45. [PMID: 19341427 DOI: 10.1111/j.1600-0609.2009.01263.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE During megakaryopoiesis, hematopoietic progenitor cells in the bone marrow proliferate and ultimately differentiate in mature megakaryocytes (MK). We and others have recently described a role for the mammalian target of Rapamycin (mTOR) in proliferation and differentiation of MK cells. Two non-redundant complexes of mTOR have been described; mTORC1 containing rapamycin-associated TOR protein (Raptor) and mTORC2 containing Rapamycin-insensitive companion of mTOR (Rictor). The individual roles of these complexes in MK development have so far not been elucidated, and were investigated in this study. METHODS We have used an siRNA approach to selectively knock down either Rictor or Raptor expression in MO7e megakaryoblastic cells. Using flow cytometry, nuclear ploidity, and cell cycling as assessed by BrdU incorporation were investigated. Electron microscopy and cotransductions with GFP-LC3 were used to quantify autophagy. Activation of intracellular signal transduction pathways was studied by Western blot analysis. RESULTS We observed a reduced cell cycling upon Rictor siRNA transduction, resulting in decreased numbers of polypoid cells. Knocking down Raptor expression resulted in a reduced expansion and a reduced cell size. In addition, increased autophagy was observed in Raptor siRNA-transduced cells, in correspondence with an attenuation of activation of the p70S6K/S6, and 4E-BP pathways. CONCLUSIONS The current study shows that the mTORC1 and mTORC2 complexes have distinct, non-redundant functions in MO7e MK cell proliferation, and development. The mTOR/Rictor complex affects megakaryopoiesis by regulating nuclear division and subsequent cell cycle progression, whereas Raptor signaling protects MK cells from autophagic cell death, enabling normal megakaryopoiesis to take place.
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Affiliation(s)
- Gwenny M Fuhler
- Division of Hematology, Department of Medicine, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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Beer PA, Green AR. Pathogenesis and management of essential thrombocythemia. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2009; 2009:621-628. [PMID: 20008247 DOI: 10.1182/asheducation-2009.1.621] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The last four years have seen an explosion in our understanding of the myeloproliferative neoplasms. Important and often unexpected insights into the molecular mechanisms responsible for these disorders have been accompanied by the development of new diagnostic tests and by an improved understanding of the relationship between the different disease entities. This review will focus on recent developments in the pathogenesis and management of essential thrombocythemia with a particular emphasis on its phenotypic overlap with polycythemia vera and primary myelofibrosis.
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Affiliation(s)
- Philip A Beer
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
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Abstract
The BCR-ABL-negative myeloproliferative neoplasms (MPNs), polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF), entered the spotlight in 2005 when the unique somatic acquired JAK2 V617F mutation was described in >95% of PV and in 50% of ET and PMF patients. For the very rare PV patients who do not harbor the JAK2 V617F mutation, exon 12 JAK2 mutants were discovered also to result in activated forms of JAK2. A minority of ET and PMF patients harbor mutations that constitutively activate the thrombopoietin receptor (TpoR). In bone marrow reconstitution models based on retroviral transduction, the phenotype induced by JAK2 V617F is less severe and different from the rapid fatal myelofibrosis induced by TpoR W515L. The reasons for these differences are unknown. Exactly by which mechanism(s) one acquired somatic mutation, JAK2 V617F, can promote three different diseases remains a mystery, although gene dosage and host genetic variation might have important functions. We review the recent progress made in deciphering signaling anomalies in PV, ET and PMF, with an emphasis on the relationship between JAK2 V617F and cytokine receptor signaling and on cross-talk with several other signaling pathways.
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