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Bone marrow Schwann cells induce hematopoietic stem cell hibernation. Int J Hematol 2014; 99:695-8. [PMID: 24817152 DOI: 10.1007/s12185-014-1588-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 04/25/2014] [Indexed: 01/09/2023]
Abstract
Hematopoietic stem cells (HSCs) are clonogenic cells capable of both self-renewal and multilineage differentiation. In adult mouse bone marrow (BM), most HSCs remain in the non-dividing G0-phase of cell cycle, in close contact with supporting cells known as the HSC "niche". In the present study, we focused on signaling mechanisms that regulate stem cell dormancy in the BM niche. We show that TGF-β type II receptor deficiency causes reduced phosphorylation of Smad2/3 and impairs long-term repopulating activity in HSCs, suggesting a significant role for TGF-β/Smad signaling in hematopoiesis. Furthermore, we aimed at defining the candidate BM niche responsible for homeostasis of hematopoiesis, and revealed that non-myelinating Schwann cells sustain HSC hibernation by converting TGF-β from its latent to its active form.
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Katayama H, Mori T, Seki Y, Anraku M, Iseki M, Ikutani M, Iwasaki Y, Yoshida N, Takatsu K, Takaki S. Lnk prevents inflammatory CD8⁺ T-cell proliferation and contributes to intestinal homeostasis. Eur J Immunol 2014; 44:1622-32. [PMID: 24536025 DOI: 10.1002/eji.201343883] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 01/15/2014] [Accepted: 02/13/2014] [Indexed: 12/17/2022]
Abstract
The intracellular adaptor Lnk (also known as SH2B3) regulates cytokine signals that control lymphohematopoiesis, and Lnk(-/-) mice have expanded B-cell, megakaryocyte, and hematopoietic stem-cell populations. Moreover, mutations in the LNK gene are found in patients with myeloproliferative disease, whereas LNK polymorphisms have recently been associated with inflammatory and autoimmune diseases, including celiac disease. Here, we describe a previously unrecognized function of Lnk in the control of inflammatory CD8(+) T-cell proliferation and in intestinal homeostasis. Mature T cells from newly generated Lnk-Venus reporter mice had low but substantial expression of Lnk, whereas Lnk expression was downregulated during homeostatic T-cell proliferation under lymphopenic conditions. The numbers of CD44(hi) IFN-γ(+) CD8(+) effector or memory T cells were found to be increased in Lnk(-/-) mice, which also exhibited shortening of villi in the small intestine. Lnk(-/-) CD8(+) T cells survived longer in response to stimulation with IL-15 and proliferated even in nonlymphopenic hosts. Transfer of Lnk(-/-) CD8(+) T cells together with WT CD4(+) T cells into Rag2-deficient mice recapitulated a sign of villous abnormality. Our results reveal a link between Lnk and immune cell-mediated intestinal tissue destruction.
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Affiliation(s)
- Hiroko Katayama
- Department of Immune Regulation, Research Institute, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan
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Abstract
LNK (SH2B3) is an adaptor protein studied extensively in normal and malignant hematopoietic cells. In these cells, it downregulates activated tyrosine kinases at the cell surface resulting in an antiproliferative effect. To date, no studies have examined activities of LNK in solid tumors. In this study, we found by in silico analysis and staining tissue arrays that the levels of LNK expression were elevated in high-grade ovarian cancer. To test the functional importance of this observation, LNK was either overexpressed or silenced in several ovarian cancer cell lines. Remarkably, overexpression of LNK rendered the cells resistant to death induced by either serum starvation or nutrient deprivation, and generated larger tumors using a murine xenograft model. In contrast, silencing of LNK decreased ovarian cancer cell growth in vitro and in vivo. Western blot studies indicated that overexpression of LNK upregulated and extended the transduction of the mitogenic signal, whereas silencing of LNK produced the opposite effects. Furthermore, forced expression of LNK reduced cell size, inhibited cell migration and markedly enhanced cell adhesion. Liquid chromatography-mass spectroscopy identified 14-3-3 as one of the LNK-binding partners. Our results suggest that in contrast to the findings in hematologic malignancies, the adaptor protein LNK acts as a positive signal transduction modulator in ovarian cancers.
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Ishihara J, Umemoto T, Yamato M, Shiratsuchi Y, Takaki S, Petrich BG, Nakauchi H, Eto K, Kitamura T, Okano T. Nov/CCN3 regulates long-term repopulating activity of murine hematopoietic stem cells via integrin αvβ3. Int J Hematol 2014; 99:393-406. [PMID: 24563081 DOI: 10.1007/s12185-014-1534-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 01/29/2014] [Accepted: 01/30/2014] [Indexed: 01/01/2023]
Abstract
Throughout life, hematopoietic stem cells (HSCs) sustain the blood cell supply through their capacities for self-renewal and multilineage differentiation. These processes are regulated within a specialized microenvironment termed the 'niche'. Here, we show a novel mechanism for regulating HSC function that is mediated by nephroblastoma overexpressed (Nov/CCN3), a matricellular protein member of the CCN family. We found that Nov contributes to the maintenance of long-term repopulating (LTR) activity through association with integrin αvβ3 on HSCs. The resultant β3 integrin outside-in signaling is dependent on thrombopoietin (TPO), a crucial cytokine involved in HSC maintenance. TPO was required for Nov binding to integrin αvβ3, and stimulated Nov expression in HSCs. However, in the presence of IFNγ, a cytokine known to impair HSC function, not only was TPO-induced expression of Nov suppressed, but the LTR activity was conversely impaired by TPO-mediated ligation of integrin αvβ3 with exogenous ligands, including Nov, as well. Thus, Nov/integrin αvβ3-mediated maintenance of HSCs appears to be modulated by simultaneous stimulation by other cytokines. Our finding suggests that this system contributes to the regulation of HSCs within the bone marrow niche.
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Affiliation(s)
- Jun Ishihara
- Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, 8-1 Kawadacho, Shinjuku-ku, Tokyo, 162-8666, Japan
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55
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Sonoda Y. Human CD34-negative Hematopoietic Stem Cells. STEM CELL BIOLOGY AND REGENERATIVE MEDICINE 2014. [DOI: 10.1007/978-1-4939-1001-4_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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56
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Aghabozorg Afjeh SS, Ghaderian SMH, Mirfakhraie R, Piryaei M, Zaim Kohan H. Association Study of rs3184504 C>T Polymorphism in Patients With Coronary Artery Disease. INTERNATIONAL JOURNAL OF MOLECULAR AND CELLULAR MEDICINE 2014; 3:157-65. [PMID: 25317402 PMCID: PMC4170489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/21/2014] [Accepted: 07/12/2014] [Indexed: 10/31/2022]
Abstract
Cardiovascular disease has become the main factor of death and birth defects in the world and also in Iran. New clinical studies have shown that early diagnosis of patients with coronary artery disease (CAD) can contribute to effective prevention or therapeutic structures, which reduce mortality or the next chance of cardiovascular events, and increase the quality of life. Most studies on CAD disease and its genetic risk factors so far, have been done excluding the Iranian population. PubMed was used to search for all relevant studies published on or before 2013 and rs3184504 was selected for association study for CAD. A total of 200 subjects with 100 cases and 100 controls were ultimately included in the analysis. Blood samples were collected and after DNA extraction the DNA analysis was performed by TaqMan Probe Real Time PCR to evaluate the association between candidate variant with the disease and some blood biochemical factors. Our study demonstrated that there was not a direct association between rs3184504 C>T variant with risk of CAD in Iranian population, whereas, there is a significant association between this variant with increased blood LDL and diastolic blood pressure. Further molecular analysis and other disease association studies are necessary in the Iranian population.
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Affiliation(s)
| | - Sayyed Mohammad Hossein Ghaderian
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Corresponding author: Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Reza Mirfakhraie
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Piryaei
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hooshang Zaim Kohan
- Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran
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Lnk adaptor suppresses radiation resistance and radiation-induced B-cell malignancies by inhibiting IL-11 signaling. Proc Natl Acad Sci U S A 2013; 110:20599-604. [PMID: 24297922 DOI: 10.1073/pnas.1319665110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Lnk (Sh2b3) adaptor protein dampens the response of hematopoietic stem cells and progenitors (HSPCs) to a variety of cytokines by inhibiting JAK2 signaling. As a consequence, Lnk(-/-) mice develop hematopoietic hyperplasia, which progresses to a phenotype resembling the nonacute phase of myeloproliferative neoplasm. In addition, Lnk mutations have been identified in human myeloproliferative neoplasms and acute leukemia. We find that Lnk suppresses the development of radiation-induced acute B-cell malignancies in mice. Lnk-deficient HSPCs recover more effectively from irradiation than their wild-type counterparts, and this resistance of Lnk(-/-) HSPCs to radiation underlies the subsequent emergence of leukemia. A search for the mechanism responsible for radiation resistance identified the cytokine IL-11 as being critical for the ability of Lnk(-/-) HSPCs to recover from irradiation and subsequently become leukemic. In IL-11 signaling, wild-type Lnk suppresses tyrosine phosphorylation of the Src homology region 2 domain-containing phosphatase-2/protein tyrosine phosphatase nonreceptor type 11 and its association with the growth factor receptor-bound protein 2, as well as activation of the Erk MAP kinase pathway. Indeed, Src homology region 2 domain-containing phosphatase-2 has a binding motif for the Lnk Src Homology 2 domain that is phosphorylated in response to IL-11 stimulation. IL-11 therefore drives a pathway that enhances HSPC radioresistance and radiation-induced B-cell malignancies, but is normally attenuated by the inhibitory adaptor Lnk.
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Yamamoto R, Morita Y, Ooehara J, Hamanaka S, Onodera M, Rudolph KL, Ema H, Nakauchi H. Clonal analysis unveils self-renewing lineage-restricted progenitors generated directly from hematopoietic stem cells. Cell 2013; 154:1112-1126. [PMID: 23993099 DOI: 10.1016/j.cell.2013.08.007] [Citation(s) in RCA: 500] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/20/2013] [Accepted: 08/06/2013] [Indexed: 12/19/2022]
Abstract
Consensus holds that hematopoietic stem cells (HSCs) give rise to multipotent progenitors (MPPs) of reduced self-renewal potential and that MPPs eventually produce lineage-committed progenitor cells in a stepwise manner. Using a single-cell transplantation system and marker mice, we unexpectedly found myeloid-restricted progenitors with long-term repopulating activity (MyRPs), which are lineage-committed to megakaryocytes, megakaryocyte-erythroid cells, or common myeloid cells (MkRPs, MERPs, or CMRPs, respectively) in the phenotypically defined HSC compartment together with HSCs. Paired daughter cell assays combined with transplantation revealed that HSCs can give rise to HSCs via symmetric division or directly differentiate into MyRPs via asymmetric division (yielding HSC-MkRP or HSC-CMRP pairs). These myeloid bypass pathways could be essential for fast responses to ablation stress. Our results show that loss of self-renewal and stepwise progression through specific differentiation stages are not essential for lineage commitment of HSCs and suggest a revised model of hematopoietic differentiation.
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Affiliation(s)
- Ryo Yamamoto
- Division of Stem Cell Therapy, Center for Stem Cell Biology and Regeneration Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Yohei Morita
- Division of Stem Cell Therapy, Center for Stem Cell Biology and Regeneration Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan; Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena 07745, Germany
| | - Jun Ooehara
- Division of Stem Cell Therapy, Center for Stem Cell Biology and Regeneration Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Sanae Hamanaka
- Division of Stem Cell Therapy, Center for Stem Cell Biology and Regeneration Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan; Japan Science Technology Agency, ERATO, Nakauchi Stem Cell and Organ Regeneration Project, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Masafumi Onodera
- Department of Human Genetics, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Karl Lenhard Rudolph
- Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena 07745, Germany
| | - Hideo Ema
- Division of Stem Cell Therapy, Center for Stem Cell Biology and Regeneration Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Hiromitsu Nakauchi
- Division of Stem Cell Therapy, Center for Stem Cell Biology and Regeneration Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan; Japan Science Technology Agency, ERATO, Nakauchi Stem Cell and Organ Regeneration Project, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
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59
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Thrombopoietin promotes NHEJ DNA repair in hematopoietic stem cells through specific activation of Erk and NF-κB pathways and their target, IEX-1. Blood 2013; 123:509-19. [PMID: 24184684 DOI: 10.1182/blood-2013-07-515874] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Loss of hematopoietic stem cell (HSC) function and increased risk of developing hematopoietic malignancies are severe and concerning complications of anticancer radiotherapy and chemotherapy. We have previously shown that thrombopoietin (TPO), a critical HSC regulator, ensures HSC chromosomal integrity and function in response to γ-irradiation by regulating their DNA-damage response. TPO directly affects the double-strand break (DSB) repair machinery through increased DNA-protein kinase (DNA-PK) phosphorylation and nonhomologous end-joining (NHEJ) repair efficiency and fidelity. This effect is not shared by other HSC growth factors, suggesting that TPO triggers a specific signal in HSCs facilitating DNA-PK activation upon DNA damage. The discovery of these unique signaling pathways will provide a means of enhancing TPO-desirable effects on HSCs and improving the safety of anticancer DNA agents. We show here that TPO specifically triggers Erk and nuclear factor κB (NF-κB) pathways in mouse hematopoietic stem and progenitor cells (HSPCs). Both of these pathways are required for a TPO-mediated increase in DSB repair. They cooperate to induce and activate the early stress-response gene, Iex-1 (ier3), upon DNA damage. Iex-1 forms a complex with pERK and the catalytic subunit of DNA-PK, which is necessary and sufficient to promote TPO-increased DNA-PK activation and NHEJ DSB repair in both mouse and human HSPCs.
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Abstract
The SH2B adaptor protein 3 (SH2B3) gene encodes a negative regulator of cytokine signaling with a critical role in the homeostasis of hematopoietic stem cells and lymphoid progenitors. Here, we report the identification of germline homozygous SH2B3 mutations in 2 siblings affected with developmental delay and autoimmunity, one in whom B-precursor acute lymphoblastic leukemia (ALL) developed. Mechanistically, loss of SH2B3 increases Janus kinase-signal transducer and activator of transcription signaling, promotes lymphoid cell proliferation, and accelerates leukemia development in a mouse model of NOTCH1-induced ALL. Moreover, extended mutation analysis showed homozygous somatic mutations in SH2B3 in 2 of 167 ALLs analyzed. Overall, these results demonstrate a Knudson tumor suppressor role for SH2B3 in the pathogenesis of ALL and highlight a possible link between genetic predisposition factors in the pathogenesis of autoimmunity and leukemogenesis.
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61
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Gäbler K, Behrmann I, Haan C. JAK2 mutants (e.g., JAK2V617F) and their importance as drug targets in myeloproliferative neoplasms. JAKSTAT 2013; 2:e25025. [PMID: 24069563 PMCID: PMC3772115 DOI: 10.4161/jkst.25025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/13/2013] [Accepted: 05/13/2013] [Indexed: 12/25/2022] Open
Abstract
The Janus kinase 2 (JAK2) mutant V617F and other JAK mutants are found in patients with myeloproliferative neoplasms and leukemias. Due to their involvement in neoplasia and inflammatory disorders, Janus kinases are promising targets for kinase inhibitor therapy. Several small-molecule compounds are evaluated in clinical trials for myelofibrosis, and ruxolitinib (INCB018424, Jakafi®) was the first Janus kinase inhibitor to receive clinical approval. In this review we provide an overview of JAK2V617F signaling and its inhibition by small-molecule kinase inhibitors. In addition, myeloproliferative neoplasms are discussed regarding the role of JAK2V617F and other mutant proteins of possible relevance. We further give an overview about treatment options with special emphasis on possible combination therapies.
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Affiliation(s)
- Karoline Gäbler
- Signal Transduction Laboratory; Life Sciences Research Unit; University of Luxembourg; Luxembourg
| | - Iris Behrmann
- Signal Transduction Laboratory; Life Sciences Research Unit; University of Luxembourg; Luxembourg
| | - Claude Haan
- Signal Transduction Laboratory; Life Sciences Research Unit; University of Luxembourg; Luxembourg
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62
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Koren-Michowitz M, Gery S, Tabayashi T, Lin D, Alvarez R, Nagler A, Koeffler HP. SH2B3 (LNK) mutations from myeloproliferative neoplasms patients have mild loss of function against wild type JAK2 and JAK2 V617F. Br J Haematol 2013; 161:811-20. [PMID: 23590807 PMCID: PMC3672250 DOI: 10.1111/bjh.12327] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 02/26/2013] [Indexed: 12/17/2022]
Abstract
Somatic point mutations in the PH domain of SH2B3 (LNK), an adaptor protein that is highly expressed in haematopoietic cells, were recently described in patients with myeloproliferative neoplasms. We studied the effect of these mutations on the JAK2 signalling pathway in cells expressing either wild type JAK2 or the JAK2 V617F mutation. Compared to wild type SH2B3, PH domain mutants have mild loss of function, with no evidence for a dominant-negative effect. Mutants retain binding capacity for JAK2, an established SH2B3 target, as well as for the adaptor proteins 14-3-3 and CBL. Our data suggest that the loss of SH2B3 inhibitory function conferred by the PH domain mutations is mild and may collaborate with JAK2 V617F and CBL mutations in order to promote either the development or the progression of myeloproliferative neoplasms.
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Affiliation(s)
- Maya Koren-Michowitz
- Hematology/Oncology, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA 90048, USA.
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63
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Generation of engraftable hematopoietic stem cells from induced pluripotent stem cells by way of teratoma formation. Mol Ther 2013; 21:1424-31. [PMID: 23670574 DOI: 10.1038/mt.2013.71] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 03/17/2013] [Indexed: 12/31/2022] Open
Abstract
In vitro generation of hematopoietic stem cells (HSCs) from induced pluripotent stem cells (iPSCs) has the potential to provide novel therapeutic approaches for replacing bone marrow (BM) transplantation without rejection or graft versus host disease. Hitherto, however, it has proved difficult to generate truly functional HSCs transplantable to adult host mice. Here, we demonstrate a unique in vivo differentiation system yielding engraftable HSCs from mouse and human iPSCs in teratoma-bearing animals in combination with a maneuver to facilitate hematopoiesis. In mice, we found that iPSC-derived HSCs migrate from teratomas into the BM and their intravenous injection into irradiated recipients resulted in multilineage and long-term reconstitution of the hematolymphopoietic system in serial transfers. Using this in vivo generation system, we could demonstrate that X-linked severe combined immunodeficiency (X-SCID) mice can be treated by HSCs derived from gene-corrected clonal iPSCs. It should also be noted that neither leukemia nor tumors were observed in recipients after transplantation of iPSC-derived HSCs. Taken our findings together, our system presented in this report should provide a useful tool not only for the study of HSCs, but also for practical application of iPSCs in the treatment of hematologic and immunologic diseases.
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64
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65
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Stine RR, Matunis EL. JAK-STAT signaling in stem cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 786:247-67. [PMID: 23696361 DOI: 10.1007/978-94-007-6621-1_14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adult stem cells are essential for the regeneration and repair of tissues in an organism. Signals from many different pathways converge to regulate stem cell maintenance and differentiation while preventing overproliferation. Although each population of adult stem cells is unique, common themes arise by comparing the regulation of various stem cell types in an organism or by comparing similar stem cell types across species. The JAK-STAT signaling pathway, identified nearly two decades ago, is now known to be involved in many biological processes including the regulation of stem cells. Studies in Drosophila first implicated JAK-STAT signaling in the control of stem cell maintenance in the male germline stem cell microenvironment, or niche; subsequently it has been shown play a role in other niches in both Drosophila and mammals. In this chapter, we will address the role of JAK-STAT signaling in stem cells in the germline, intestinal, hematopoietic and neuronal niches in Drosophila as well as the hematopoietic and neuronal niches in mammals. We will comment on how the study of JAK-STAT signaling in invertebrate systems has helped to advance our understanding of signaling in vertebrates. In addition to the role of JAK- STAT signaling in stem cell niche homeostasis, we will also discuss the diseases, including cancers, that can arise when this pathway is misregulated.
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Affiliation(s)
- Rachel R Stine
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD, 21205 USA
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66
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Tashiro K, Omori M, Kawabata K, Hirata N, Yamaguchi T, Sakurai F, Takaki S, Mizuguchi H. Inhibition of Lnk in Mouse Induced Pluripotent Stem Cells Promotes Hematopoietic Cell Generation. Stem Cells Dev 2012; 21:3381-90. [DOI: 10.1089/scd.2012.0100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Katsuhisa Tashiro
- Laboratory of Stem Cell Regulation, National Institute of Biomedical Innovation, Osaka, Japan
| | - Miyuki Omori
- Laboratory of Stem Cell Regulation, National Institute of Biomedical Innovation, Osaka, Japan
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Kenji Kawabata
- Laboratory of Stem Cell Regulation, National Institute of Biomedical Innovation, Osaka, Japan
- Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Nobue Hirata
- Laboratory of Stem Cell Regulation, National Institute of Biomedical Innovation, Osaka, Japan
| | - Tomoko Yamaguchi
- Laboratory of Stem Cell Regulation, National Institute of Biomedical Innovation, Osaka, Japan
| | - Fuminori Sakurai
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Satoshi Takaki
- Department of Immune Regulation, National Center for Global Health and Medicine, Research Institute, Tokyo, Japan
| | - Hiroyuki Mizuguchi
- Laboratory of Stem Cell Regulation, National Institute of Biomedical Innovation, Osaka, Japan
- Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
- The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan
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67
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Norddahl GL, Wahlestedt M, Gisler S, Sigvardsson M, Bryder D. Reduced repression of cytokine signaling ameliorates age-induced decline in hematopoietic stem cell function. Aging Cell 2012; 11:1128-31. [PMID: 22809070 DOI: 10.1111/j.1474-9726.2012.00863.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Aging causes profound effects on the hematopoietic stem cell (HSC) pool, including an altered output of mature progeny and enhanced self-propagation of repopulating-defective HSCs. An important outstanding question is whether HSCs can be protected from aging. The signal adaptor protein LNK negatively regulates hematopoiesis at several cellular stages. It has remained unclear how the enhanced sensitivity to cytokine signaling caused by LNK deficiency affects hematopoiesis upon aging. Our findings demonstrate that aged LNK-/- HSCs displayed a robust overall reconstitution potential and gave rise to a hematopoietic system with a balanced lineage distribution. Although aged LNK-/- HSCs displayed a distinct molecular profile in which reduced proliferation was central, little or no difference in the proliferation of aged LNK-/- HSCs was observed after transplantation when compared to aged WT HSCs. This coincided with equal telomere maintenance in WT and LNK-/- HSCs. Collectively, our studies suggest that enhanced cytokine signaling can counteract functional age-related HSC decline.
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Affiliation(s)
- Gudmundur L Norddahl
- Lund University, Institution for Experimental Medical Science, Immunology section, BMC D14, Tornavägen 10, 221 84 Lund, Sweden
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68
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Abstract
Enormous numbers of adult blood cells are constantly regenerated throughout life from hematopoietic stem cells through a series of progenitor stages. Accessibility, robust functional assays, well-established prospective isolation, and successful clinical application made hematopoiesis the classical mammalian stem cell system. Most of the basic concepts of stem cell biology have been defined in this system. At the same time, many long-standing disputes in hematopoiesis research illustrate our still limited understanding. Here we discuss the embryonic development and lifelong maintenance of the hematopoietic system, its cellular components, and some of the hypotheses about the molecular mechanisms involved in controlling hematopoietic cell fates.
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Affiliation(s)
- Michael A Rieger
- Georg-Speyer-Haus, Institute for Biomedical Research, Frankfurt (Main), Germany
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69
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Bersenev A, Rozenova K, Balcerek J, Jiang J, Wu C, Tong W. Lnk deficiency partially mitigates hematopoietic stem cell aging. Aging Cell 2012; 11:949-59. [PMID: 22812478 DOI: 10.1111/j.1474-9726.2012.00862.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Upon aging, the number of hematopoietic stem cells (HSCs) in the bone marrow increases while their repopulation potential declines. Moreover, aged HSCs exhibit lineage bias in reconstitution experiments with an inclination toward myeloid at the expense of lymphoid potential. The adaptor protein Lnk is an important negative regulator of HSC homeostasis, as Lnk deficiency is associated with a 10-fold increase in HSC numbers in young mice. However, the age-related increase in functional HSC numbers found in wild-type HSCs was not observed in Lnk-deficient animals. Importantly, HSCs from aged Lnk null mice possess greatly enhanced self-renewal capacity and diminished exhaustion, as evidenced by serial transplant experiments. In addition, Lnk deficiency ameliorates the aging-associated lineage bias. Transcriptome analysis revealed that WT and Lnk-deficient HSCs share many aging-related changes in gene expression patterns. Nonetheless, Lnk null HSCs displayed altered expression of components in select signaling pathways with potential involvement in HSC self-renewal and aging. Taken together, these results suggest that loss of Lnk partially mitigates age-related HSC alterations.
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Affiliation(s)
- Alexey Bersenev
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104-4318, USA
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70
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Gery S, Koeffler HP. Role of the adaptor protein LNK in normal and malignant hematopoiesis. Oncogene 2012; 32:3111-8. [DOI: 10.1038/onc.2012.435] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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71
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Velazquez L. The Lnk adaptor protein: a key regulator of normal and pathological hematopoiesis. Arch Immunol Ther Exp (Warsz) 2012; 60:415-29. [PMID: 22990499 DOI: 10.1007/s00005-012-0194-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 08/06/2012] [Indexed: 01/24/2023]
Abstract
The development and function of blood cells are regulated by specific growth factors/cytokines and their receptors' signaling pathways. In this way, these factors influence cell survival, proliferation and differentiation of hematopoietic cells. Central to this positive and/or negative control are the adaptor proteins. Since their identification 10 years ago, members of the Lnk adaptor protein family have proved to be important activators and/or inhibitors in the hematopoietic, immune and vascular system. In particular, the generation of animal and cellular models for the Lnk and APS proteins has helped establish the physiological role of these molecules through the identification of their specific signaling pathways and the characterization of their binding partners. Moreover, the recent identification of mutations in the LNK gene in myeloproliferative disorders, as well as the correlation of a single nucleotide polymorphism on LNK with hematological, immune and vascular diseases have suggested its involvement in the pathophysiology of these malignancies. The latter findings have thus raised the possibility of addressing Lnk signaling for the treatment of certain human diseases. This review therefore describes the pathophysiological role of this adaptor protein in hematological malignancies and the potential benefits of Lnk therapeutic targeting.
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Affiliation(s)
- Laura Velazquez
- UMR U978 Inserm/Université Paris 13, UFR SMBH, Bobigny, France.
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72
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Abstract
Fms-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase with important roles in hematopoietic progenitor cell survival and proliferation. It is mutated in approximately one-third of AML patients, mostly by internal tandem duplications (ITDs). Adaptor protein Lnk is a negative regulator of hematopoietic cytokine signaling. In the present study, we show that Lnk interacts physically with both wild-type FLT3 (FLT3-WT) and FLT3-ITD through the SH2 domains. We have identified the tyrosine residues 572, 591, and 919 of FLT3 as phosphorylation sites involved in direct binding to Lnk. Lnk itself was tyrosine phosphorylated by both FLT3 ligand (FL)-activated FLT3-WT and constitutively activated FLT3-ITD. Both shRNA-mediated depletion and forced overexpression of Lnk demonstrated that activation signals emanating from both forms of FLT3 are under negative regulation by Lnk. Moreover, Lnk inhibited 32D cell proliferation driven by different FLT3 variants. Analysis of primary BM cells from Lnk-knockout mice showed that Lnk suppresses the expansion of FL-stimulated hematopoietic progenitors, including lymphoid-primed multipotent progenitors. The results of the present study show that through direct binding to FLT3, Lnk suppresses FLT3-WT/ITD-dependent signaling pathways involved in the proliferation of hematopoietic cells. Therefore, modulation of Lnk expression levels may provide a unique therapeutic approach for FLT3-ITD-associated hematopoietic disease.
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73
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Heffner GC, Clutter MR, Nolan GP, Weissman IL. Novel hematopoietic progenitor populations revealed by direct assessment of GATA1 protein expression and cMPL signaling events. Stem Cells 2012; 29:1774-82. [PMID: 21898686 DOI: 10.1002/stem.719] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Hematopoietic stem cells (HSCs) must exhibit tight regulation of both self-renewal and differentiation to maintain homeostasis of the hematopoietic system as well as to avoid aberrations in growth that may result in leukemias or other disorders. In this study, we sought to understand the molecular basis of lineage determination, with particular focus on factors that influence megakaryocyte/erythrocyte-lineage commitment, in hematopoietic stem and progenitor cells. We used intracellular flow cytometry to identify two novel hematopoietic progenitor populations within the mouse bone-marrow cKit(+) Lineage (-) Sca1(+) (KLS) Flk2 (+) compartment that differ in their protein-level expression of GATA1, a critical megakaryocyte/erythrocyte-promoting transcription factor. GATA1-high repopulating cells exhibited the cell surface phenotype KLS Flk2(+ to int), CD150(int), CD105(+), cMPL(+), and were termed "FSE cells." GATA1-low progenitors were identified as KLS Flk2(+), CD150(-), and cMPL(-), and were termed "Flk(+) CD150(-) cells." FSE cells had increased megakaryocyte/platelet potential in culture and transplant settings and exhibited a higher clonal frequency of colony-forming unit-spleen activity compared with Flk(+) CD150(-) cells, suggesting functional consequences of GATA1 upregulation in promoting megakaryocyte and erythroid lineage priming. Activation of ERK and AKT signal-transduction cascades was observed by intracellular flow cytometry in long-term HSCs and FSE cells, but not in Flk(+) CD150(-) cells in response to stimulation with thrombopoietin, an important megakaryocyte-promoting cytokine. We provide a mechanistic rationale for megakaryocyte/erythroid bias within KLS Flk2(+) cells, and demonstrate how assessment of intracellular factors and signaling events can be used to refine our understanding of lineage commitment during early definitive hematopoiesis.
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Affiliation(s)
- Garrett C Heffner
- Program in Immunology, Ludwig Center at Stanford, Institute of Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California, USA
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74
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Jiang J, Balcerek J, Rozenova K, Cheng Y, Bersenev A, Wu C, Song Y, Tong W. 14-3-3 regulates the LNK/JAK2 pathway in mouse hematopoietic stem and progenitor cells. J Clin Invest 2012; 122:2079-91. [PMID: 22546852 DOI: 10.1172/jci59719] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 03/09/2012] [Indexed: 11/17/2022] Open
Abstract
Hematopoietic stem and progenitor cell (HSPC) functions are governed by intricate signaling networks. The tyrosine kinase JAK2 plays an essential role in cytokine signaling during hematopoiesis. The adaptor protein LNK is a critical determinant of this process through its inhibitory interaction with JAK2, thereby limiting HSPC self-renewal. LNK deficiency promotes myeloproliferative neoplasm (MPN) development in mice, and LNK loss-of-function mutations are found in human MPNs, emphasizing its pivotal role in normal and malignant HSPCs. Here, we report the identification of 14-3-3 proteins as LNK binding partners. 14-3-3 interfered with the LNK-JAK2 interaction, thereby alleviating LNK inhibition of JAK2 signaling and cell proliferation. Binding of 14-3-3 required 2 previously unappreciated serine phosphorylation sites in LNK, and we found that their phosphorylation is mediated by glycogen synthase kinase 3 and PKA kinases. Mutations of these residues abrogated the interaction and augmented the growth inhibitory function of LNK. Conversely, forced 14-3-3 binding constrained LNK function. Furthermore, interaction with 14-3-3 sequestered LNK in the cytoplasm away from the plasma membrane-proximal JAK2. Importantly, bone marrow transplantation studies revealed an essential role for 14-3-3 in HSPC reconstitution that can be partially mitigated by LNK deficiency. We believe that, together, this work implicates 14-3-3 proteins as novel and positive HSPC regulators by impinging on the LNK/JAK2 pathway.
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Affiliation(s)
- Jing Jiang
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104-4318, USA
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75
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Ahlenius H, Devaraju K, Monni E, Oki K, Wattananit S, Darsalia V, Iosif RE, Torper O, Wood JC, Braun S, Jagemann L, Nuber UA, Englund E, Jacobsen SEW, Lindvall O, Kokaia Z. Adaptor protein LNK is a negative regulator of brain neural stem cell proliferation after stroke. J Neurosci 2012; 32:5151-64. [PMID: 22496561 PMCID: PMC6622083 DOI: 10.1523/jneurosci.0474-12.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 02/25/2012] [Accepted: 02/29/2012] [Indexed: 01/07/2023] Open
Abstract
Ischemic stroke causes transient increase of neural stem and progenitor cell (NSPC) proliferation in the subventricular zone (SVZ), and migration of newly formed neuroblasts toward the damaged area where they mature to striatal neurons. The molecular mechanisms regulating this plastic response, probably involved in structural reorganization and functional recovery, are poorly understood. The adaptor protein LNK suppresses hematopoietic stem cell self-renewal, but its presence and role in the brain are poorly understood. Here we demonstrate that LNK is expressed in NSPCs in the adult mouse and human SVZ. Lnk(-/-) mice exhibited increased NSPC proliferation after stroke, but not in intact brain or following status epilepticus. Deletion of Lnk caused increased NSPC proliferation while overexpression decreased mitotic activity of these cells in vitro. We found that Lnk expression after stroke increased in SVZ through the transcription factors STAT1/3. LNK attenuated insulin-like growth factor 1 signaling by inhibition of AKT phosphorylation, resulting in reduced NSPC proliferation. Our findings identify LNK as a stroke-specific, endogenous negative regulator of NSPC proliferation, and suggest that LNK signaling is a novel mechanism influencing plastic responses in postischemic brain.
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Affiliation(s)
| | | | | | - Koichi Oki
- Laboratory of Neural Stem Cell Biology and Therapy
| | | | | | | | - Olof Torper
- Laboratory of Neural Stem Cell Biology and Therapy
| | | | | | | | | | - Elisabet Englund
- and Division of Neuropathology, Lund Stem Cell Center, Lund University Hospital, SE-221 84 Lund, Sweden
| | | | | | - Zaal Kokaia
- Laboratory of Neural Stem Cell Biology and Therapy
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76
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Devallière J, Chatelais M, Fitau J, Gérard N, Hulin P, Velazquez L, Turner CE, Charreau B. LNK (SH2B3) is a key regulator of integrin signaling in endothelial cells and targets α-parvin to control cell adhesion and migration. FASEB J 2012; 26:2592-606. [PMID: 22441983 DOI: 10.1096/fj.11-193383] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Focal adhesion (FA) formation and disassembly play an essential role in adherence and migration of endothelial cells. These processes are highly regulated and involve various signaling molecules that are not yet completely identified. Lnk [Src homology 2-B3 (SH2B3)] belongs to a family of SH2-containing proteins with important adaptor functions. In this study, we showed that Lnk distribution follows that of vinculin, localizing Lnk in FAs. Inhibition of Lnk by RNA interference resulted in decreased spreading, whereas sustained expression dramatically increases the number of focal and cell-matrix adhesions. We demonstrated that Lnk expression impairs FA turnover and cell migration and regulates β1-integrin-mediated signaling via Akt and GSK3β phosphorylation. Moreover, the α-parvin protein was identified as one of the molecular targets of Lnk responsible for impaired FA dynamics and cell migration. Finally, we established the ILK protein as a new molecular partner for Lnk and proposed a model in which Lnk regulates α-parvin expression through its interaction with ILK. Collectively, our results underline the adaptor Lnk as a novel and effective key regulator of integrin-mediated signaling controlling endothelial cell adhesion and migration.
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Affiliation(s)
- Julie Devallière
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 643, Nantes, France
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77
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Suzuki N, Yamazaki S, Ema H, Yamaguchi T, Nakauchi H, Takaki S. Homeostasis of hematopoietic stem cells regulated by the myeloproliferative disease associated-gene product Lnk/Sh2b3 via Bcl-xL. Exp Hematol 2011; 40:166-74.e3. [PMID: 22101255 DOI: 10.1016/j.exphem.2011.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 10/25/2011] [Accepted: 11/09/2011] [Indexed: 01/15/2023]
Abstract
Hematopoietic stem cells (HSCs) are maintained at a very low frequency in adult bone marrow under steady-state conditions. However, it is not fully understood how homeostasis of bone marrow HSCs is maintained. We attempted to identify a key molecule involved in the regulation of HSC numbers, a factor that, in the absence of Lnk, leads to HSC expansion. Here, we demonstrate that upon stimulation with thrombopoietin, expression of Bcl-xL, an antiapoptotic protein, was highly enhanced in Lnk-deficient HSCs compared to normal HSCs. As a result, Lnk-deficient HSCs underwent reduced apoptosis following exposure to lethal radiation. Downregulation of Bcl-xL expression in Lnk-deficient HSCs by short-hairpin RNA resulted in a great reduction of their capacity for reconstitution. These findings suggest that Lnk/Sh2b3 constrains the expression of Bcl-xL and that the loss of Lnk/Sh2b3 function enhances survival of HSCs by inhibiting apoptosis. Furthermore, our observations indicate that HSCs in patients with an Lnk/Sh2b3 mutation might become resistant to apoptosis due to thrombopoietin-mediated enhanced expression of Bcl-xL. Consequently, reduced apoptosis could facilitate accumulation of HSCs with oncogenic mutations leading to development of myeloproliferative disorders.
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Affiliation(s)
- Nao Suzuki
- Laboratory of Stem Cell Therapy, Center for Experimental Medicine, The Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, Japan
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78
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Wang TC, Chiu H, Chang YJ, Hsu TY, Chiu IM, Chen L. The adaptor protein SH2B3 (Lnk) negatively regulates neurite outgrowth of PC12 cells and cortical neurons. PLoS One 2011; 6:e26433. [PMID: 22028877 PMCID: PMC3196555 DOI: 10.1371/journal.pone.0026433] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 09/27/2011] [Indexed: 12/11/2022] Open
Abstract
SH2B adaptor protein family members (SH2B1-3) regulate various physiological responses through affecting signaling, gene expression, and cell adhesion. SH2B1 and SH2B2 were reported to enhance nerve growth factor (NGF)-induced neuronal differentiation in PC12 cells, a well-established neuronal model system. In contrast, SH2B3 was reported to inhibit cell proliferation during the development of immune system. No study so far addresses the role of SH2B3 in the nervous system. In this study, we provide evidence suggesting that SH2B3 is expressed in the cortex of embryonic rat brain. Overexpression of SH2B3 not only inhibits NGF-induced differentiation of PC12 cells but also reduces neurite outgrowth of primary cortical neurons. SH2B3 does so by repressing NGF-induced activation of PLCγ, MEK-ERK1/2 and PI3K-AKT pathways and the expression of Egr-1. SH2B3 is capable of binding to phosphorylated NGF receptor, TrkA, as well as SH2B1β. Our data further demonstrate that overexpression of SH2B3 reduces the interaction between SH2B1β and TrkA. Consistent with this finding, overexpressing the SH2 domain of SH2B3 is sufficient to inhibit NGF-induced neurite outgrowth. Together, our data demonstrate that SH2B3, unlike the other two family members, inhibits neuronal differentiation of PC12 cells and primary cortical neurons. Its inhibitory mechanism is likely through the competition of TrkA binding with the positive-acting SH2B1 and SH2B2.
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Affiliation(s)
- Tien-Cheng Wang
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Hsun Chiu
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Yu-Jung Chang
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Tai-Yu Hsu
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Ing-Ming Chiu
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Linyi Chen
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
- Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan
- * E-mail:
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79
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Tracking single hematopoietic stem cells in vivo using high-throughput sequencing in conjunction with viral genetic barcoding. Nat Biotechnol 2011; 29:928-33. [PMID: 21964413 PMCID: PMC3196379 DOI: 10.1038/nbt.1977] [Citation(s) in RCA: 316] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 08/19/2011] [Indexed: 01/19/2023]
Abstract
Disentangling cellular heterogeneity is a challenge in many fields, particularly in the stem cell and cancer biology fields. Here, we demonstrate how to combine viral genetic barcoding with high-throughput sequencing to track single cells in a heterogeneous population. We use this technique to track the in vivo differentiation of unitary hematopoietic stem cells (HSCs). The results are consistent with single cell transplantation studies, but require two orders of magnitude fewer mice. In addition to its high throughput, the high sensitivity of the technique allows for a direct examination of the clonality of sparse cell populations such as HSCs. We show how these capabilities offer a clonal perspective of the HSC differentiation process. In particular, our data suggests that HSCs do not equally contribute to blood cells after irradiation-mediated transplantation, and that two distinct HSC differentiation patterns co-exist in the same recipient mouse post irradiation. This technique can be applied to any viral accessible cell type for both in vitro and in vivo processes.
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80
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Abstract
Abstract
Myeloproliferative neoplasms (MPNs) are clonal disorders characterized by excessive production of mature blood cells. In the majority of classic MPN—polycythemia vera, essential thrombocythemia, and primitive myelofibrosis—driver oncogenic mutations affecting Janus kinase 2 (JAK2) or MPL lead to constitutive activation of cytokine-regulated intracellular signaling pathways. LNK, c-CBL, or SOCSs (all negative regulators of signaling pathways), although infrequently targeted, may either drive the disease or synergize with JAK2 and MPL mutations. IZF1 deletions or TP53 mutations are mainly found at transformation phases and are present at greater frequency than in de novo acute myeloid leukemias. Loss-of-function mutations in 3 genes involved in epigenetic regulation, TET2, ASXL1, and EZH2, may be early events preceding JAK2V617F but may also occur late during disease progression. They are more frequently observed in PMF than PV and ET and are also present in other types of malignant myeloid diseases. A likely hypothesis is that they facilitate clonal selection, allowing the dominance of the JAK2V617F subclone during the chronic phase and, together with cooperating mutations, promote blast crisis. Their precise roles in hematopoiesis and in the pathogenesis of MPN, as well as their prognostic impact and potential as a therapeutic target, are currently under investigation.
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81
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Devallière J, Charreau B. The adaptor Lnk (SH2B3): an emerging regulator in vascular cells and a link between immune and inflammatory signaling. Biochem Pharmacol 2011; 82:1391-402. [PMID: 21723852 DOI: 10.1016/j.bcp.2011.06.023] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 12/20/2022]
Abstract
A better knowledge of the process by which inflammatory extracellular signals are relayed from the plasma membrane to specific intracellular sites is a key step to understand how inflammation develops and how it is regulated. This review focuses on Lnk (SH2B3) a member, with SH2B1 and SH2B2, of the SH2B family of adaptor proteins that influences a variety of signaling pathways mediated by Janus kinase and receptor tyrosine kinases. SH2B adaptor proteins contain conserved dimerization, pleckstrin homology, and SH2 domains. Initially described as a regulator of hematopoiesis and lymphocyte differentiation, Lnk now emerges as a key regulator in hematopoeitic and non hematopoeitic cells such as endothelial cells (EC) moderating growth factor and cytokine receptor-mediated signaling. In EC, Lnk is a negative regulator of TNF signaling that reduce proinflammatory phenotype and prevent EC from apoptosis. Lnk is a modulator in integrin signaling and actin cytoskeleton organization in both platelets and EC with an impact on cell adhesion, migration and thrombosis. In this review, we discuss some recent insights proposing Lnk as a key regulator of bone marrow-endothelial progenitor cell kinetics, including the ability to cell growth, endothelial commitment, mobilization, and recruitment for vascular regeneration. Finally, novel findings also provided evidences that mutations in Lnk gene are strongly linked to myeloproliferative disorders but also autoimmune and inflammatory syndromes where both immune and vascular cells display a role. Overall, these studies emphasize the importance of the Lnk adaptor molecule not only as prognostic marker but also as potential therapeutic target.
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82
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Chatelais M, Devallière J, Galli C, Charreau B. Gene transfer of the adaptor Lnk (SH2B3) prevents porcine endothelial cell activation and apoptosis: implication for xenograft’s cytoprotection. Xenotransplantation 2011; 18:108-20. [DOI: 10.1111/j.1399-3089.2011.00629.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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83
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Coskun S, Hirschi KK. Establishment and regulation of the HSC niche: Roles of osteoblastic and vascular compartments. ACTA ACUST UNITED AC 2011; 90:229-42. [PMID: 21181885 DOI: 10.1002/bdrc.20194] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hematopoietic stem cells (HSC) are multi-potent cells that function to generate a lifelong supply of all blood cell types. During mammalian embryogenesis, sites of hematopoiesis change over the course of gestation: from extraembryonic yolk sac and placenta, to embryonic aorta-gonad-mesonephros region, fetal liver, and finally fetal bond marrow where HSC reside postnatally. These tissues provide microenviroments for de novo HSC formation, as well as HSC maturation and expansion. Within adult bone marrow, HSC self-renewal and differentiation are thought to be regulated by two major cellular components within their so-called niche: osteoblasts and vascular endothelial cells. This review focuses on HSC generation within, and migration to, different tissues during development, and also provides a summary of major regulatory factors provided by osteoblasts and vascular endothelial cells within the adult bone marrow niche.
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Affiliation(s)
- Suleyman Coskun
- Center for Cell and Gene Therapy, Baylor College of Medicine; Houston, Texas, 77030, USA
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84
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Seita J, Weissman IL. Hematopoietic stem cell: self-renewal versus differentiation. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 2:640-53. [PMID: 20890962 DOI: 10.1002/wsbm.86] [Citation(s) in RCA: 541] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mammalian blood system, containing more than 10 distinct mature cell types, stands on one specific cell type, hematopoietic stem cell (HSC). Within the system, only HSCs possess the ability of both multipotency and self-renewal. Multipotency is the ability to differentiate into all functional blood cells. Self-renewal is the ability to give rise to HSC itself without differentiation. Since mature blood cells (MBCs) are predominantly short-lived, HSCs continuously provide more differentiated progenitors while properly maintaining the HSC pool size throughout life by precisely balancing self-renewal and differentiation. Thus, understanding the mechanisms of self-renewal and differentiation of HSC has been a central issue. In this review, we focus on the hierarchical structure of the hematopoietic system, the current understanding of microenvironment and molecular cues regulating self-renewal and differentiation of adult HSCs, and the currently emerging systems approaches to understand HSC biology.
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Affiliation(s)
- Jun Seita
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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85
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Abstract
The process of megakaryopoiesis and platelet production is complex, with the potential for regulation at multiple stages. Megakaryocytes are derived from the hematopoietic stem cell through successive lineage commitment steps, and they undergo a unique maturation process that includes polyploidization, development of an extensive internal demarcation membrane system, and finally formation of pro-platelet processes. Platelets are shed from these processes into vascular sinusoids within the bone marrow. Megakaryocyte differentiation is regulated both positively and negatively by transcription factors and cytokine signaling. Thrombopoietin (TPO) is the most important hematopoietic cytokine for platelet production. Clinically, acquired and inherited mutations affecting megakaryocytic transcription factors and thrombopoietin signaling have been identified in disorders of thrombocytopenia and thrombocytosis.
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Affiliation(s)
- Amy E Geddis
- Pediatric Hematology-Oncology, University of California, San Diego, La Jolla, CA 92023, USA.
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86
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Expression level and differential JAK2-V617F–binding of the adaptor protein Lnk regulates JAK2-mediated signals in myeloproliferative neoplasms. Blood 2010; 116:5961-71. [DOI: 10.1182/blood-2009-12-256768] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Abstract
Activating mutations in signaling molecules, such as JAK2-V617F, have been associated with myeloproliferative neoplasms (MPNs). Mice lacking the inhibitory adaptor protein Lnk display deregulation of thrombopoietin/thrombopoietin receptor signaling pathways and exhibit similar myeloproliferative characteristics to those found in MPN patients, suggesting a role for Lnk in the molecular pathogenesis of these diseases. Here, we showed that LNK levels are up-regulated and correlate with an increase in the JAK2-V617F mutant allele burden in MPN patients. Using megakaryocytic cells, we demonstrated that Lnk expression is regulated by the TPO-signaling pathway, thus indicating an important negative control loop in these cells. Analysis of platelets derived from MPN patients and megakaryocytic cell lines showed that Lnk can interact with JAK2-WT and V617F through its SH2 domain, but also through an unrevealed JAK2-binding site within its N-terminal region. In addition, the presence of the V617F mutation causes a tighter association with Lnk. Finally, we found that the expression level of the Lnk protein can modulate JAK2-V617F–dependent cell proliferation and that its different domains contribute to the inhibition of multilineage and megakaryocytic progenitor cell growth in vitro. Together, our results indicate that changes in Lnk expression and JAK2-V617F–binding regulate JAK2-mediated signals in MPNs.
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87
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Martelli AM, Evangelisti C, Chiarini F, Grimaldi C, Cappellini A, Ognibene A, McCubrey JA. The emerging role of the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling network in normal myelopoiesis and leukemogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:991-1002. [DOI: 10.1016/j.bbamcr.2010.04.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 04/06/2010] [Accepted: 04/06/2010] [Indexed: 12/19/2022]
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88
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Bersenev A, Wu C, Balcerek J, Jing J, Kundu M, Blobel GA, Chikwava KR, Tong W. Lnk constrains myeloproliferative diseases in mice. J Clin Invest 2010; 120:2058-69. [PMID: 20458146 PMCID: PMC2877957 DOI: 10.1172/jci42032] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 03/31/2010] [Indexed: 12/24/2022] Open
Abstract
Hematopoietic stem and progenitor cell (HSPC) expansion is regulated by intrinsic signaling pathways activated by cytokines. The intracellular kinase JAK2 plays an essential role in cytokine signaling, and activating mutations in JAK2 are found in a number of hematologic malignancies. We previously demonstrated that lymphocyte adaptor protein (Lnk, also known as Sh2b3) binds JAK2 and attenuates its activity, thereby limiting HSPC expansion. Here we show that loss of Lnk accelerates and exacerbates oncogenic JAK2-induced myeloproliferative diseases (MPDs) in mice. Specifically, Lnk deficiency enhanced cytokine-independent JAK/STAT signaling and augmented the ability of oncogenic JAK2 to expand myeloid progenitors in vitro and in vivo. An activated form of JAK2, unable to bind Lnk, caused greater myeloid expansion than activated JAK2 alone and accelerated myelofibrosis, indicating that Lnk directly inhibits oncogenic JAK2 in constraining MPD development. In addition, Lnk deficiency cooperated with the BCR/ABL oncogene, the product of which does not directly interact with or depend on JAK2 or Lnk, in chronic myeloid leukemia (CML) development, suggesting that Lnk also acts through endogenous pathways to constrain HSPCs. Consistent with this idea, aged Lnk-/- mice spontaneously developed a CML-like MPD. Taken together, our data establish Lnk as a bona fide suppressor of MPD in mice and raise the possibility that Lnk dysfunction contributes to the development of hematologic malignancies in humans.
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Affiliation(s)
- Alexey Bersenev
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA.
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pathology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Chao Wu
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA.
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pathology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Joanna Balcerek
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA.
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pathology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jiang Jing
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA.
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pathology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Mondira Kundu
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA.
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pathology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Gerd A. Blobel
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA.
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pathology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kudakwashe R. Chikwava
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA.
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pathology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Wei Tong
- Division of Hematology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Department of Pathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA.
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Pathology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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89
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Kamei N, Kwon SM, Alev C, Ishikawa M, Yokoyama A, Nakanishi K, Yamada K, Horii M, Nishimura H, Takaki S, Kawamoto A, Ii M, Akimaru H, Tanaka N, Nishikawa SI, Ochi M, Asahara T. Lnk deletion reinforces the function of bone marrow progenitors in promoting neovascularization and astrogliosis following spinal cord injury. Stem Cells 2010; 28:365-75. [PMID: 19859984 DOI: 10.1002/stem.243] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Lnk is an intracellular adaptor protein reported as a negative regulator of proliferation in c-Kit positive, Sca-1 positive, lineage marker-negative (KSL) bone marrow cells. The KSL fraction in mouse bone marrow is believed to represent a population of hematopoietic and endothelial progenitor cells (EPCs). We report here that, in vitro, Lnk(-/-) KSL cells form more EPC colonies than Lnk(+/+) KSL cells and show higher expression levels of endothelial marker genes, including CD105, CD144, Tie-1, and Tie2, than their wild-type counterparts. In vivo, the administration of Lnk(+/+) KSL cells to a mouse spinal cord injury model promoted angiogenesis, astrogliosis, axon growth, and functional recovery following injury, with Lnk(-/-) KSL being significantly more effective in inducing and promoting these regenerative events. At day 3 following injury, large vessels could be observed in spinal cords treated with KSL cells, and reactive astrocytes were found to have migrated along these large vessels. We could further show that the enhancement of astrogliosis appears to be caused in conjunction with the acceleration of angiogenesis. These findings suggest that Lnk deletion reinforces the commitment of KSL cells to EPCs, promoting subsequent repair of injured spinal cord through the acceleration of angiogenesis and astrogliosis.
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Affiliation(s)
- Naosuke Kamei
- Group of Vascular Regeneration, Institute of Biomedical Research and Innovation, 2-2 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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90
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Morita Y, Ema H, Nakauchi H. Heterogeneity and hierarchy within the most primitive hematopoietic stem cell compartment. ACTA ACUST UNITED AC 2010; 207:1173-82. [PMID: 20421392 PMCID: PMC2882827 DOI: 10.1084/jem.20091318] [Citation(s) in RCA: 315] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hematopoietic stem cells (HSCs) have been extensively characterized based on functional definitions determined by experimental transplantation into lethally irradiated mice. In mice, HSCs are heterogeneous with regard to self-renewal potential, in vitro colony-forming activity, and in vivo behavior. We attempted prospective isolation of HSC subsets with distinct properties among CD34(-/low) c-Kit+Sca-1+Lin- (CD34-KSL) cells. CD34-KSL cells were divided, based on CD150 expression, into three fractions: CD150high, CD150med, and CD150neg cells. Compared with the other two fractions, CD150high cells were significantly enriched in HSCs, with great self-renewal potential. In vitro colony assays revealed that decreased expression of CD150 was associated with reduced erythroblast/megakaryocyte differentiation potential. All three fractions were regenerated only from CD150high cells in recipient mice. Using single-cell transplantation studies, we found that a fraction of CD150high cells displayed latent and barely detectable myeloid engraftment in primary-recipient mice but progressive and multilineage reconstitution in secondary-recipient mice. These findings highlight the complexity and hierarchy of reconstitution capability, even among HSCs in the most primitive compartment.
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Affiliation(s)
- Yohei Morita
- Division of Stem Cell Therapy and FACS Core Laboratory, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
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91
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Han L, Schuringa JJ, Mulder A, Vellenga E. Dasatinib impairs long-term expansion of leukemic progenitors in a subset of acute myeloid leukemia cases. Ann Hematol 2010; 89:861-71. [PMID: 20387067 PMCID: PMC2908401 DOI: 10.1007/s00277-010-0948-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 03/17/2010] [Indexed: 11/25/2022]
Abstract
A number of signaling pathways might be frequently disrupted in acute myeloid leukemia (AML). We questioned whether the dual SRC/ABL kinase inhibitor dasatinib can affect AML cells and whether differences can be observed with normal CD34(+) cells. First, we demonstrated that normal cord blood (CB) CD34(+) cells were unaffected by dasatinib at a low concentration (0.5 nM) in the long-term culture on MS5 stromal cells. No changes were observed in proliferation, differentiation, and colony formation. In a subset of AML cases (3/15), a distinct reduction in cell proliferation was observed, ranging from 48% to 91% inhibition at 0.5 nM of dasatinib, in particular, those characterized by BCR-ABL or KIT mutations. Moreover, the inhibitory effects of dasatinib were cytokine specific. Stem cell factor-mediated proliferation was significantly impaired, associated with a reduced phosphorylation of ERK1/2 and STAT5, whereas no effect was observed on interleukin-3 and thrombopoietin-mediated signaling despite SRC activation. In conclusion, this study demonstrates that dasatinib is a potential inhibitor in a subgroup of AML, especially those that express BCR-ABL or KIT mutations.
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Affiliation(s)
- Lina Han
- Department of Hematology, University of Groningen and University Medical Center Groningen, P.O. Box 30001, 9700 RB Groningen, the Netherlands
- Department of Hematology, The First Clinical College of Harbin Medical University, Harbin, China
| | - Jan Jacob Schuringa
- Department of Hematology, University of Groningen and University Medical Center Groningen, P.O. Box 30001, 9700 RB Groningen, the Netherlands
| | - André Mulder
- Department of Clinical Chemistry, University of Groningen and University Medical Center Groningen, Groningen, the Netherlands
| | - Edo Vellenga
- Department of Hematology, University of Groningen and University Medical Center Groningen, P.O. Box 30001, 9700 RB Groningen, the Netherlands
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92
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Takizawa H, Nishimura S, Takayama N, Oda A, Nishikii H, Morita Y, Kakinuma S, Yamazaki S, Okamura S, Tamura N, Goto S, Sawaguchi A, Manabe I, Takatsu K, Nakauchi H, Takaki S, Eto K. Lnk regulates integrin alphaIIbbeta3 outside-in signaling in mouse platelets, leading to stabilization of thrombus development in vivo. J Clin Invest 2009; 120:179-90. [PMID: 20038804 DOI: 10.1172/jci39503] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 10/28/2009] [Indexed: 12/20/2022] Open
Abstract
The nature of the in vivo cellular events underlying thrombus formation mediated by platelet activation remains unclear because of the absence of a modality for analysis. Lymphocyte adaptor protein (Lnk; also known as Sh2b3) is an adaptor protein that inhibits thrombopoietin-mediated signaling, and as a result, megakaryocyte and platelet counts are elevated in Lnk-/- mice. Here we describe an unanticipated role for Lnk in stabilizing thrombus formation and clarify the activities of Lnk in platelets transduced through integrin alphaIIbbeta3-mediated outside-in signaling. We equalized platelet counts in wild-type and Lnk-/- mice by using genetic depletion of Lnk and BM transplantation. Using FeCl3- or laser-induced injury and in vivo imaging that enabled observation of single platelet behavior and the multiple steps in thrombus formation, we determined that Lnk is an essential contributor to the stabilization of developing thrombi within vessels. Lnk-/- platelets exhibited a reduced ability to fully spread on fibrinogen and mediate clot retraction, reduced tyrosine phosphorylation of the beta3 integrin subunit, and reduced binding of Fyn to integrin alphaIIbbeta3. These results provide new insight into the mechanism of alphaIIbbeta3-based outside-in signaling, which appears to be coordinated in platelets by Lnk, Fyn, and integrins. Outside-in signaling modulators could represent new therapeutic targets for the prevention of cardiovascular events.
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Affiliation(s)
- Hitoshi Takizawa
- Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo, Japan
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93
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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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94
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Nishino T, Miyaji K, Ishiwata N, Arai K, Yui M, Asai Y, Nakauchi H, Iwama A. Ex vivo expansion of human hematopoietic stem cells by a small-molecule agonist of c-MPL. Exp Hematol 2009; 37:1364-1377.e4. [DOI: 10.1016/j.exphem.2009.09.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 08/31/2009] [Accepted: 09/02/2009] [Indexed: 10/20/2022]
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95
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Sigvardsson M. New light on the biology and developmental potential of haematopoietic stem cells and progenitor cells. J Intern Med 2009; 266:311-24. [PMID: 19765177 DOI: 10.1111/j.1365-2796.2009.02154.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Even though stem cells have been identified in several tissues, one of the best understood somatic stem cells is the bone marrow residing haematopoietic stem cell (HSC). These cells are able to generate all types of blood cells found in the periphery over the lifetime of an animal, making them one of the most profound examples of tissue-restricted stem cells. HSC therapy also represents one of the absolutely most successful cell-based therapies applied both in the treatment of haematological disorders and cancer. However, to fully explore the clinical potential of HSCs we need to understand the molecular regulation of cell maturation and lineage commitment. The extensive research effort invested in this area has resulted in a rapid development of the understanding of the relationship between different blood cell lineages and increased understanding for how a balanced composition of blood cells can be generated. In this review, several of the basic features of HSCs, as well as their multipotent and lineage-restricted offspring, are addressed, providing a current view of the haematopoietic development tree. Some of the basic mechanisms believed to be involved in lineage restriction events including activities of permissive and instructive external signals are also discussed, besides transcription factor networks and epigenetic alterations to provide an up-to-date view of early haematopoiesis.
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Affiliation(s)
- M Sigvardsson
- The Institution for Clinical and Experimental Research, Linköping University, Sweden.
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96
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Insights into signaling and function of hematopoietic stem cells at the single-cell level. Curr Opin Hematol 2009; 16:255-8. [PMID: 19465850 DOI: 10.1097/moh.0b013e32832c6705] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW Development of a technique prospectively to isolate hematopoietic stem cells (HSCs) to near homogeneity has enabled clonal analysis and thus converted our understanding of HSCs from conceptual and qualitative to realistic and quantitative. Recent studies have revealed that despite their high proliferation potential, most HSCs are in G0 and enter cell cycle only after a long interval. This dormancy of HSCs, which seems to be important for long-term maintenance of 'stemness', appears to be regulated by the exchange of signals between HSCs and the bone marrow niche. Analysis of intersignaling and intrasignaling events in HSCs in and out of the bone marrow niche has begun. RECENT FINDINGS With the help of advances in confocal microscopy, laser scanning microscopy, and personal computer computational power over the last decade, it has become evident that thrombopoietin/c-Mpl signaling plays a role in HSC self-renewal and AKT-forkhead box O signaling in HSC dormancy. Furthermore, transforming growth factor-beta has been indicated as a candidate niche signal to induce hibernation in HSCs. SUMMARY Understanding of the signaling events between HSCs and niche is critical not only for stem cell biology in general and for transplantation medicine but also for the development of novel cancer therapy.
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97
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Gery S, Gueller S, Nowak V, Sohn J, Hofmann WK, Koeffler HP. Expression of the adaptor protein Lnk in leukemia cells. Exp Hematol 2009; 37:585-592.e2. [PMID: 19375649 DOI: 10.1016/j.exphem.2009.01.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 01/08/2009] [Accepted: 01/28/2009] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Tyrosine kinases are involved in cytokine signaling and are frequently aberrantly activated in hematological malignancies. Lnk, a negative regulator of cytokine signaling, plays critical nonredundant roles in hematopoiesis. By binding to phosphorylated tyrosine kinases, Lnk inhibits major cytokine receptor signaling, including c-KIT; erythropoietin receptor-Janus kinase 2 (JAK2); and MPL-JAK2. In the present study, we investigated Lnk expression and possible function in transformed hematopoietic cells. MATERIALS AND METHODS Coimmunoprecipitations were performed to identify binding between Lnk and mutant tyrosine kinases. Proliferation assays were done to examine the affect of Lnk overexpression on cancer cell growth. Real-time polymerase chain reaction analysis was used to determine Lnk expression in patient samples. RESULTS We show that, in parallel to binding wild-type JAK2 and c-KIT, Lnk associates with and is phosphorylated by mutant alleles of JAK2 and c-KIT. In contrast, Lnk does not bind to and is not phosphorylated by BCR-ABL fusion protein. Ectopic expression of Lnk strongly attenuates growth of some leukemia cell lines, while others as well as most solid tumor cancer cell lines are either moderately inhibited or completely insensitive to Lnk. Furthermore, Lnk-mediated growth inhibition is associated with differential downregulation of phosphatidylinositol 3 kinase/Akt/mammalian target of rapamycin and mitogen-activated protein kinase/extracellular signal-regulated kinase signaling in leukemia cell lines. Surprisingly, analysis of Lnk in a large panel of myelodysplastic syndrome and acute myeloid leukemia patient samples revealed high levels of Lnk in nearly half of the samples. CONCLUSION Although how leukemic cells overcome the antiproliferative effects of Lnk is not yet clear, our data highlight the multifaceted role negative feedback mechanisms play in malignant transformation.
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Affiliation(s)
- Sigal Gery
- Division of Hematology/Oncology, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, Calif. 90048, USA.
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98
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Prospective isolation and molecular characterization of hematopoietic stem cells with durable self-renewal potential. Blood 2009; 113:6342-50. [PMID: 19377048 DOI: 10.1182/blood-2008-12-192054] [Citation(s) in RCA: 240] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Hematopoietic stem cells (HSCs) are generally defined by their dual properties of pluripotency and extensive self-renewal capacity. However, a lack of experimental clarity as to what constitutes extensive self-renewal capacity coupled with an absence of methods to prospectively isolate long-term repopulating cells with defined self-renewal activities has made it difficult to identify the essential components of the self-renewal machinery and investigate their regulation. We now show that cells capable of repopulating irradiated congenic hosts for 4 months and producing clones of cells that can be serially transplanted are selectively and highly enriched in the CD150(+) subset of the EPCR(+)CD48(-)CD45(+) fraction of mouse fetal liver and adult bone marrow cells. In contrast, cells that repopulate primary hosts for the same period but show more limited self-renewal activity are enriched in the CD150(-) subset. Comparative transcriptome analyses of these 2 subsets with each other and with HSCs whose self-renewal activity has been rapidly extinguished in vitro revealed 3 new genes (VWF, Rhob, Pld3) whose elevated expression is a consistent and selective feature of the long-term repopulating cells with durable self-renewal capacity. These findings establish the identity of a phenotypically and molecularly distinct class of pluripotent hematopoietic cells with lifelong self-renewal capacity.
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99
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Takaki S. [Sh2b3/Lnk family adaptor proteins in the regulation of lymphohematopoiesis]. NIHON RINSHO MEN'EKI GAKKAI KAISHI = JAPANESE JOURNAL OF CLINICAL IMMUNOLOGY 2009; 31:440-7. [PMID: 19122374 DOI: 10.2177/jsci.31.440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sh2b3/Lnk consisting of an N-terminal proline-rich region, PH-, SH2-domains and a tyrosine phosphorylation site, forms an intracellular adaptor protein family conserved from drosophila to mammals, together with Sh2b1/SH2-B and Sh2b2/APS (adaptor protein with PH and SH2 domains). Lnk negatively regulates lymphopoiesis and early hematopoiesis. The lnk-deficiency results in enhanced production of B cells, and expansion as well as enhanced function of hematopoietic stem cells (HSCs), demonstrating negative regulatory functions of Sh2b3/Lnk in cytokine signaling. Our recent studies also revealed that Sh2b3/Lnk functions in responses controlled by cell adhesion and in crosstalk between integrin- and cytokine-mediated signaling. Importantly, recent genome-wide association studies of the autoimmune type 1 diabetes or celiac disease identified risk variants in the SH2B3/LNK region, indicating possible unrevealed functions mediated by this adaptor molecule. This review summarizes roles of Sh2b3/Lnk in the regulation of B-lymphopoiesis and HSCs expansion and function, and briefly introduces our approach for modulating HSCs function by targeting Sh2b3/Lnk-mediated pathways.
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Affiliation(s)
- Satoshi Takaki
- Research Institute, International Medical Center of Japan
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100
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Kalaitzidis D, Neel BG. Flow-cytometric phosphoprotein analysis reveals agonist and temporal differences in responses of murine hematopoietic stem/progenitor cells. PLoS One 2008; 3:e3776. [PMID: 19020663 PMCID: PMC2582484 DOI: 10.1371/journal.pone.0003776] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 11/03/2008] [Indexed: 02/07/2023] Open
Abstract
Hematopoietic stem cells (HSCs) are probably the best-studied adult tissue-restricted stem cells. Although methods for flow cytometric detection of phosphoproteins in hematopoeitic progenitors and mature cells are available, analogous protocols for HSC are lacking. We present a robust method to study intracellular signaling in immunophenotypically-defined murine HSC/progenitor cell (HPC)-enriched populations. Using this method, we uncover differences in the response dynamics of several phosphoproteins representative of the Ras/MAP-Kinase(K), PI3K, mTOR and Jak/STAT pathways in HSC/HPCs stimulated by Scf, Thpo, as well as several other important HSC/HPC agonists.
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Affiliation(s)
- Demetrios Kalaitzidis
- Hematology/Oncology-Cancer Biology Program, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
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