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Wirth F, Lubosch A, Hamelmann S, Nakchbandi IA. Fibronectin and Its Receptors in Hematopoiesis. Cells 2020; 9:cells9122717. [PMID: 33353083 PMCID: PMC7765895 DOI: 10.3390/cells9122717] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/08/2020] [Accepted: 12/15/2020] [Indexed: 02/07/2023] Open
Abstract
Fibronectin is a ubiquitous extracellular matrix protein that is produced by many cell types in the bone marrow and distributed throughout it. Cells of the stem cell niche produce the various isoforms of this protein. Fibronectin not only provides the cells a scaffold to bind to, but it also modulates their behavior by binding to receptors on the adjacent hematopoietic stem cells and stromal cells. These receptors, which include integrins such as α4β1, α9β1, α4β7, α5β1, αvβ3, Toll-like receptor-4 (TLR-4), and CD44, are found on the hematopoietic stem cell. Because the knockout of fibronectin is lethal during embryonal development and because fibronectin is produced by almost all cell types in mammals, the study of its role in hematopoiesis is difficult. Nevertheless, strong and direct evidence exists for its stimulation of myelopoiesis and thrombopoiesis using in vivo models. Other reviewed effects can be deduced from the study of fibronectin receptors, which showed their activation modifies the behavior of hematopoietic stem cells. Erythropoiesis was only stimulated under hemolytic stress, and mostly late stages of lymphocytic differentiation were modulated. Because fibronectin is ubiquitously expressed, these interactions in health and disease need to be taken into account whenever any molecule is evaluated in hematopoiesis.
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Affiliation(s)
- Franziska Wirth
- Institute of Immunology, University of Heidelberg, 69120 Heidelberg, Germany; (F.W.); (A.L.); (S.H.)
| | - Alexander Lubosch
- Institute of Immunology, University of Heidelberg, 69120 Heidelberg, Germany; (F.W.); (A.L.); (S.H.)
| | - Stefan Hamelmann
- Institute of Immunology, University of Heidelberg, 69120 Heidelberg, Germany; (F.W.); (A.L.); (S.H.)
| | - Inaam A. Nakchbandi
- Institute of Immunology, University of Heidelberg, 69120 Heidelberg, Germany; (F.W.); (A.L.); (S.H.)
- Max-Planck Institute for Medical Research, 69120 Heidelberg, Germany
- Correspondence: ; Tel.: +49-622-156-8744
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Rossnagl S, Altrock E, Sens C, Kraft S, Rau K, Milsom MD, Giese T, Samstag Y, Nakchbandi IA. EDA-Fibronectin Originating from Osteoblasts Inhibits the Immune Response against Cancer. PLoS Biol 2016; 14:e1002562. [PMID: 27653627 PMCID: PMC5031442 DOI: 10.1371/journal.pbio.1002562] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 08/25/2016] [Indexed: 01/29/2023] Open
Abstract
Osteoblasts lining the inner surface of bone support hematopoietic stem cell differentiation by virtue of proximity to the bone marrow. The osteoblasts also modify their own differentiation by producing various isoforms of fibronectin (FN). Despite evidence for immune regulation by osteoblasts, there is limited knowledge of how osteoblasts modulate cells of the immune system. Here, we show that extra domain A (EDA)-FN produced by osteoblasts increases arginase production in myeloid-derived cells, and we identify α5β1 as the mediating receptor. In different mouse models of cancer, osteoblasts or EDA-FN was found to up-regulate arginase-1 expression in myeloid-derived cells, resulting in increased cancer growth. This harmful effect can be reduced by interfering with the integrin α5β1 receptor or inhibiting arginase. Conversely, in tissue injury, the expression of arginase-1 is normally beneficial as it dampens the immune response to allow wound healing. We show that EDA-FN protects against excessive fibrotic tissue formation in a liver fibrosis model. Our results establish an immune regulatory function for EDA-FN originating from the osteoblasts and identify new avenues for enhancing the immune reaction against cancer. Osteoblasts produce an isoform of fibronectin (EDA-fibronectin) that acts on myeloid cells to increase arginase-1 expression and protect against fibrosis. However, it can also enhance cancer growth; interfering with the interaction between EDA-fibronectin and its receptor diminishes this effect. Osteoblasts, which are the cells that produce bone, line the inner surface of the bone and are adjacent to the marrow that generates all the different blood cells. Osteoblasts have a close relationship with hematopoiesis, and it has been shown that a transient elimination of osteoblasts leads to the decrease of hematopoietic stem cells and progenitor cells. Fibronectin (FN) is an extracellular matrix protein with a known role in hematopoiesis in vitro that is secreted by osteoblasts. Here, we analyze the role of FN in hematopoiesis and find that an isoform that contains the extra domain A (EDA) and is produced by the osteoblasts affects both the number and future behavior of a subset of immune cells. EDA-FN protects against excessive fibrotic tissue formation in a liver fibrosis model. The same process, however, is detrimental in cancer, because it prevents the organism from mounting a potent immune response against the cancer and induces an increase of cancer growth. Mechanistically, we find that the EDA domain binds to the cell surface receptor α5β1 integrin and enhances the production of the anti-inflammatory and immunosuppressive factor arginase-1. We conclude that EDA-FN production by osteoblasts modulates immune cell behavior, and that interfering with this mechanism opens up new possibilities for enhancing an immune reaction against cancer.
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Affiliation(s)
- Stephanie Rossnagl
- Max-Planck Institute of Biochemistry, Martinsried, Germany
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
| | - Eva Altrock
- Max-Planck Institute of Biochemistry, Martinsried, Germany
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
| | - Carla Sens
- Max-Planck Institute of Biochemistry, Martinsried, Germany
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
| | - Sabrina Kraft
- Max-Planck Institute of Biochemistry, Martinsried, Germany
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
| | - Katrin Rau
- Max-Planck Institute of Biochemistry, Martinsried, Germany
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
| | - Michael D. Milsom
- German Cancer Research Center (DKFZ), Division of Stem Cells and Cancer, Experimental Hematology Group, and Heidelberg Institute for Stem Cell Technology and Experimental Medicine, gGmbH (HI-STEM), Heidelberg, Germany
| | - Thomas Giese
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
| | - Yvonne Samstag
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
| | - Inaam A. Nakchbandi
- Max-Planck Institute of Biochemistry, Martinsried, Germany
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
- * E-mail:
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Duval C, Zaniolo K, Leclerc S, Salesse C, Guérin SL. Characterization of the human α9 integrin subunit gene: Promoter analysis and transcriptional regulation in ocular cells. Exp Eye Res 2015; 135:146-63. [PMID: 25746835 DOI: 10.1016/j.exer.2015.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 01/26/2015] [Accepted: 03/02/2015] [Indexed: 11/29/2022]
Abstract
α9β1 is the most recent addition to the integrin family of membrane receptors and consequently remains the one that is the least characterized. To better understand how transcription of the human gene encoding the α9 subunit is regulated, we cloned the α9 promoter and characterized the regulatory elements that are required to ensure its transcription. Transfection of α9 promoter/CAT plasmids in primary cultured human corneal epithelial cells (HCECs) and uveal melanoma cell lines demonstrated the presence of both negative and positive regulatory elements along the α9 promoter and positioned the basal α9 promoter to within 118 bp from the α9 mRNA start site. In vitro DNaseI footprinting and in vivo ChIP analyses demonstrated the binding of the transcription factors Sp1, c-Myb and NFI to the most upstream α9 negative regulatory element. The transcription factors Sp1 and NFI were found to bind the basal α9 promoter individually but Sp1 binding clearly predominates when both transcription factors are present in the same extract. Suppression of Sp1 expression through RNAi also caused a dramatic reduction in the expression of the α9 gene. Most of all, addition of tenascin-C (TNC), the ligand of α9β1, to the tissue culture plates prior to seeding HCECs increased α9 transcription whereas it simultaneously decreased expression of the α5 integrin subunit gene. This dual regulatory action of TNC on the transcription of the α9 and α5 genes suggests that both these integrins must work together to appropriately regulate cell adhesion, migration and differentiation that are hallmarks of tissue wound healing.
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Affiliation(s)
- Céline Duval
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Karine Zaniolo
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Steeve Leclerc
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Christian Salesse
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada; Département d'Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Sylvain L Guérin
- Centre Universitaire d'Ophtalmologie-Recherche, Axe Médecine Régénératrice, Hôpital du Saint-Sacrement, Centre de Recherche FRQS du CHU de Québec, Québec, Canada; Département d'Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.
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Hosoi H, Ikeda H, Imai N, Amaike C, Wang L, Orito Y, Yamane M, Ueno H, Ideno M, Nukaya I, Enoki T, Mineno J, Takesako K, Hirano S, Shiku H. Stimulation through very late antigen-4 and -5 improves the multifunctionality and memory formation of CD8⁺ T cells. Eur J Immunol 2014; 44:1747-58. [PMID: 24723437 DOI: 10.1002/eji.201343969] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 02/11/2014] [Accepted: 04/04/2014] [Indexed: 01/01/2023]
Abstract
T cells express multiple integrin molecules. The significance of signaling through these molecules on acquisition of T-cell effector functions and memory formation capacity remains largely unknown. Moreover, the impact of stimulation through these signals on the generation of T cells for adoptive immunotherapy has not been elucidated. In this study, using a recombinant fragment of fibronectin, CH-296, we demonstrated that stimulation via very late Ag (VLA)-4 and VLA-5 in human and BALB/c mouse CD8(+) T cells, in combination with TCR stimulation, enhances effector multifunctionality and in vivo memory formation. Using TCR-transgenic mouse-derived CD8(+) T cells expressing TCR specific for the syngeneic CMS5 fibrosarcoma-derived tumor Ag, we showed that stimulation by CH-296 improved the ability of tumor-specific CD8(+) T cells to inhibit CMS5 tumor growth when adoptively transferred into hosts with progressing tumors. Improved antitumor effects were associated with decreased infiltration of Foxp3(+) CD4(+) Treg cells in tumors. These results suggest that stimulation via VLA-4 and VLA-5 modulates the qualities of effector T cells and could potentially increase the efficacy of adoptive therapy against cancer.
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Affiliation(s)
- Hayato Hosoi
- Department of Immuno-Gene Therapy, Mie University Graduate School of Medicine, Tsu, Japan; Department of Surgical Oncology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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5
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CD41 expression marks myeloid-biased adult hematopoietic stem cells and increases with age. Blood 2013; 121:4463-72. [PMID: 23564910 DOI: 10.1182/blood-2012-09-457929] [Citation(s) in RCA: 230] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The hematopoietic stem cell (HSC) compartment is heterogeneous, yet our understanding of the identities of different HSC subtypes is limited. Here we show that platelet integrin CD41 (αIIb), currently thought to only transiently mark fetal HSCs, is expressed on an adult HSC subtype that accumulates with age. CD41+ HSCs were largely quiescent and exhibited myeloerythroid and megakaryocyte gene priming, governed by Gata1, whereas CD41- HSCs were more proliferative and exhibited lymphoid gene priming. When isolated without the use of blocking antibodies, CD41+ HSCs possessed long-term repopulation capacity on serial transplantations and showed a marked myeloid bias compared with CD41- HSCs, which yielded a more lymphoid-biased progeny. CD41-knockout (KO) mice displayed multilineage hematopoietic defects coupled with decreased quiescence and survival of HSCs, suggesting that CD41 is functionally relevant for HSC maintenance and hematopoietic homeostasis. Transplantation experiments indicated that CD41-KO-associated defects are long-term transplantable, HSC-derived and, in part, mediated through the loss of platelet mass leading to decreases in HSC exposure to important platelet released cytokines, such as transforming growth factor β1. In summary, our data provide a novel marker to identify a myeloid-biased HSC subtype that becomes prevalent with age and highlights the dogma of HSC regulation by their progeny.
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Macpherson GR, Hanson CA, Thompson DM, Perella CM, Cmarik JL, Ruscetti SK. Retrovirus-transformed erythroleukemia cells induce central nervous system failure in a new syngeneic mouse model of meningeal leukemia. Leuk Res 2011; 36:369-76. [PMID: 21924771 DOI: 10.1016/j.leukres.2011.08.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/15/2011] [Accepted: 08/22/2011] [Indexed: 12/25/2022]
Abstract
Lack of suitable mouse models for central nervous system (CNS)-associated leukemias has hindered mechanism-guided development of therapeutics. By transplanting retrovirus-transformed mouse erythroleukemia cells into syngeneic mice, we developed a new animal model of meningeal leukemia associated with rapid paralysis. Necropsy revealed massive proliferation of the leukemic cells in the bone marrow (BM) followed by pathological angiogenesis and invasion of the leukemic cells into the meninges of the CNS. Further analysis demonstrated that the erythroleukemia cells secreted high levels of VEGF and preferentially adhered in vitro to fibronectin. This unique animal model for meningeal leukemia should facilitate studies of engraftment and proliferation of leukemic cells in the BM and their invasion of the CNS as well as pre-clinical evaluation of experimental therapeutics for CNS-associated leukemias.
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Affiliation(s)
- Gordon R Macpherson
- Laboratory of Cancer Prevention, National Cancer Institute-Frederick, Frederick, MD 21702-1201, USA
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Rosová I, Link D, Nolta JA. shRNA-mediated decreases in c-Met levels affect the differentiation potential of human mesenchymal stem cells and reduce their capacity for tissue repair. Tissue Eng Part A 2011; 16:2627-39. [PMID: 20367286 DOI: 10.1089/ten.tea.2009.0363] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mesenchymal stem cells/marrow stromal cells (MSC) are adult multipotent cells that can augment tissue repair. We previously demonstrated that culturing MSC in hypoxic conditions causes upregulation of the hepatocyte growth factor (HGF) receptor c-Met, allowing them to respond more robustly to HGF. MSC preconditioned in hypoxic environments contributed to restoration of blood flow after an ischemic injury more rapidly than MSC cultured in normoxic conditions. We now investigated the specific role of HGF/c-Met signaling in MSC function. An shRNA-mediated knockdown (KD) of c-Met in MSC did not alter their phenotypic profile, proliferation, or viability in vitro. However, we determined that while HGF/c-Met signaling does not play a role in the adipogenic differentiation of the cells, the disruption of this signaling pathway inhibited the ability of MSC to differentiate into the osteogenic and chondrogenic lineages. We next assessed the impact of c-Met KD on human MSC function in a xenogeneic hindlimb ischemia injury model. A 70% KD of c-Met in MSC resulted in a significant decrease in their capacity to regenerate blood flow to the ischemic limb, as compared to the MSC transduced with control shRNA. MSC with only a 60% KD of c-Met exhibited an intermediate capacity to restore blood flow, suggesting that MSC function is sensitive to the dosage of c-Met signaling. The current study highlights the significance of HGF/c-Met signaling in the capacity of MSC to restore blood flow after an ischemic injury and in their ability to differentiate into the osteogenic and chondrogenic lineages.
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Affiliation(s)
- Ivana Rosová
- Division of Oncology, Stem Cell Biology Program, Washington University School of Medicine, St. Louis, Missouri, USA
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Lazar-Karsten P, Dorn I, Meyer G, Lindner U, Driller B, Schlenke P. The influence of extracellular matrix proteins and mesenchymal stem cells on erythropoietic cell maturation. Vox Sang 2010; 101:65-76. [DOI: 10.1111/j.1423-0410.2010.01453.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Meyerrose T, Olson S, Pontow S, Kalomoiris S, Jung Y, Annett G, Bauer G, Nolta JA. Mesenchymal stem cells for the sustained in vivo delivery of bioactive factors. Adv Drug Deliv Rev 2010; 62:1167-74. [PMID: 20920540 DOI: 10.1016/j.addr.2010.09.013] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 09/24/2010] [Indexed: 12/13/2022]
Abstract
Mesenchymal stem cells (MSC) are a promising tool for cell therapy, either through direct contribution to the repair of bone, tendon and cartilage or as an adjunct therapy through protein production and immune mediation. They are an attractive vehicle for cellular therapies due to a variety of cell intrinsic and environmentally responsive properties. Following transplantation, MSC are capable of systemic migration, are not prone to tumor formation, and appear to tolerize the immune response across donor mismatch. These attributes combine to allow MSC to reside in many different tissue types without disrupting the local microenvironment and, in some cases, responding to the local environment with appropriate protein secretion. We describe work done by our group and others in using human MSC for the sustained in vivo production of supraphysiological levels of cytokines for the support of cotransplanted hematopoietic stem cells and enzymes that are deficient in animal models of lysosomal storage disorders such as MPSVII. In addition, the use of MSC engineered to secrete protein products has been reviewed in several fields of tissue injury repair, including but not limited to revascularization after myocardial infarction, regeneration of intervertebral disc defects and spine therapy, repair of stroke, therapy for epilepsy, skeletal tissue repair, chondrogenesis/knee and joint repair, and neurodegenerative diseases. Genetically engineered MSC have thus proven safe and efficacious in numerous animal models of disease modification and tissue repair and are poised to be tested in human clinical trials. The potential for these interesting cells to secrete endogenous or transgene products in a sustained and long-term manner is highly promising and is discussed in the current review.
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Horiuchi Y, Onodera M, Miyagawa Y, Sato B, Onda K, Katagiri YU, Okita H, Okada M, Otsu M, Kume A, Okuyama T, Fujimoto J, Kuratsuji T, Kiyokawa N. Kinetics and effect of integrin expression on human CD34(+) cells during murine leukemia virus-derived retroviral transduction with recombinant fibronectin for stem cell gene therapy. Hum Gene Ther 2010; 20:777-83. [PMID: 19284246 DOI: 10.1089/hum.2008.159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The CH-296 recombinant fragment of human fibronectin is essential for murine leukemia virus (MLV)-derived retroviral transduction of CD34(+) cells for the purpose of stem cell gene therapy. Although the major effect of CH-296 is colocalization of the MLV-derived retrovirus and target cells at specific adhesion domains of CH-296 mediated by integrins expressed on CD34(+) cells, the precise roles of the integrins are unclear. We examined the kinetics of integrin expression on CD34(+) cells during the course of MLV-derived retrovirus-mediated gene transduction with CH-296. Flow cytometry revealed that the levels of both very late activation protein (VLA)-4 and VLA-5 on CD34(+) cells freshly isolated from cord blood were insufficient for effective MLV-derived retroviral transduction. However, increases were achieved during culture for preinduction and MLV-derived retrovirus-mediated gene transduction in the presence of a cocktail of cytokines. In addition, we confirmed by using specific antibodies that inhibition of the cell adhesion mediated by the integrins significantly reduced transduction efficiency, indicating that integrin expression is indeed important for CH-296-based MLV-derived retroviral transduction. Only a few cytokines are capable of inducing integrin expression, and stem cell factor plus thrombopoietin was found to be the minimal combination that was sufficient for effective transduction of an MLV-derived retrovirus based on CH-296. Our findings should be useful for improving the culture conditions for CH-296-based MLV-derived retroviral transduction in stem cell gene therapy.
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Affiliation(s)
- Yasuomi Horiuchi
- Department of Developmental Biology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan
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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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Harima A, Nakaseko C, Yokota A, Kitagawa M, Morimoto C, Harigaya K, Saito Y. Fibronectin promotes cell proliferation of human pre-B cell line via its interactions with VLA-4 and VLA-5. ACTA ACUST UNITED AC 2009; 13:236-43. [PMID: 18796250 DOI: 10.1179/102453308x348315] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Fibronectin (FN) is thought to play an important role in various aspects of hematopoiesis through binding to very late antigen (VLA)-4 and VLA-5. Little is known, however, about the effects of FN on the proliferation of B cell progenitors. In this study, we investigated the effects of immobilized FN on the proliferation of the pre-B cell line, Nalm-6, which expresses both VLA-4 and VLA-5. Immobilized FN significantly promoted the proliferation of Nalm-6 cells through the synergistic effects of VLA-4 and VLA-5. Furthermore, FN induced the phosphorylation of mitogen-activated protein kinases (MAPKs) of Nalm-6 cells. The MAPK kinase 1 (MEK1) inhibitor, PD98059, and Src family tyrosine kinase inhibitor, herbimycin A, inhibited the FN-promoted proliferation of Nalm-6 cells. These results demonstrate that the interactions of FN and VLA-4/VLA-5 transmit the growth signals that are mediated through Src family tyrosine kinases and the MAPK cascade in Nalm-6 cells. The precise mechanism of synergistic effect of VLA-4 and VLA-5 on FN-promoted proliferation of Nalm-6 cells should be further investigated.
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Affiliation(s)
- Akane Harima
- Department of Clinical Cell Biology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 2, Japan
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Abstract
PURPOSE OF REVIEW To provide an overview of the hematopoietic stem cell (HSC) niche in the bone marrow. In addition to highlighting recent advances in the field, we will also discuss components of the niche that may contribute to the development of cancer, or cancer metastases to the bone. RECENT FINDINGS Much progress has been very recently made in the understanding of the cellular and molecular interactions in the HSC microenvironment. These recent findings point out the extraordinary complexity of the HSC microenvironment. Emerging data also suggest convergence of signals important for HSC and for leukemia or metastatic disease support. SUMMARY The HSC niche comprises complex interactions between multiple cell types and molecules requiring cell-cell signaling as well as local secretion. These components can be thought of as therapeutic targets not only for HSC expansion, but also to modify behavior of hematopoietic malignancies and cancer metastases to the bone.
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Oncostatin M-Mediated Regulation of KIT-Ligand-Induced Extracellular Signal-Regulated Kinase Signaling Maintains Hematopoietic Repopulating Activity of Lin−CD34+CD133+Cord Blood Cells. Stem Cells 2008; 26:2164-72. [DOI: 10.1634/stemcells.2007-1049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Rosová I, Dao M, Capoccia B, Link D, Nolta JA. Hypoxic preconditioning results in increased motility and improved therapeutic potential of human mesenchymal stem cells. Stem Cells 2008; 26:2173-82. [PMID: 18511601 DOI: 10.1634/stemcells.2007-1104] [Citation(s) in RCA: 523] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mesenchymal stem cells (MSC) are adult multipotent cells found in bone marrow, adipose tissue, and other adult tissues. MSC have been shown to improve regeneration of injured tissues in vivo, but the mechanisms remain unclear. Typically, MSC are cultured under ambient, or normoxic, conditions (21% oxygen). However, the physiological niches for MSC in the bone marrow and other sites have much lower oxygen tension. When used as a therapeutic tool to repair tissue injuries, MSC cultured in standard conditions must adapt from 21% oxygen in culture to less than 1% oxygen in the ischemic tissue. We therefore examined the effects of preculturing human bone marrow-derived MSC in hypoxic conditions (1%-3% oxygen) to elucidate the best conditions that enhance their tissue regenerative potential. We demonstrated that MSC cultured in hypoxia activate the Akt signaling pathway while maintaining their viability and cell cycle rates. We also showed that MSC cultured in hypoxia induced expression of cMet, the major receptor for hepatocyte growth factor (HGF), and enhanced cMet signaling. MSC cultured in hypoxic conditions increased their migration rates. Since migration and HGF responsiveness are thought to be key mediators of MSC recruitment and/or activation in vivo, we next examined the tissue regenerative potential of MSC cultured under hypoxic conditions, using a murine hind limb ischemia model. We showed that local expression of HGF is increased in ischemic muscle in this model. Intra-arterial injection of MSC cultured in either normoxic or hypoxic conditions 24 hours after surgical induction of hind limb ischemia enhanced revascularization compared with saline controls. However, restoration of blood flow was observed significantly earlier in mice that had been injected with hypoxic preconditioned MSC. Collectively, these data suggest that preculturing MSC under hypoxic conditions prior to transplantation improves their tissue regenerative potential. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Ivana Rosová
- Stem Cell Program, University of California at Davis, Room 653, 2425 Stockton Boulevard, Sacramento, California 95817, USA
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Alternative RNA splicing produces multiple forms of c-Myb with unique transcriptional activities. Mol Cell Biol 2008; 28:2091-101. [PMID: 18195038 DOI: 10.1128/mcb.01870-07] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The c-Myb transcription factor regulates the proliferation and differentiation of hematopoietic cells, and activated alleles of c-myb induce leukemias and lymphomas in animals. Relatively minor changes in the structure of c-Myb protein change the genes that it regulates and can unleash its latent transforming activities. Here, quantitative assays were used to analyze the alternative splicing of human c-myb transcripts. We identified an array of variant transcripts, expressed in highly regulated, lineage-specific patterns, that were formed through the use of alternate exons 8A, 9A, 9B, 10A, 13A, and 14A. Expression levels of the different splice variant transcripts were regulated independently of one another during human hematopoietic cell differentiation, and the alternative splicing of c-myb mRNAs was increased in primary leukemia samples. The alternatively spliced c-myb transcripts were associated with polysomes and encoded a series of c-Myb proteins with identical DNA binding domains but unique C-terminal domains. In several types of assays, the variant c-Myb proteins exhibited quantitative and qualitative differences in transcriptional activities and specificities. The results suggest that the human c-myb gene encodes a family of related proteins with different transcriptional activities. Enhanced alternative splicing may be a mechanism for unmasking the transforming activity of c-myb in human leukemias.
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Maxwell DJ, Bonde J, Hess DA, Hohm SA, Lahey R, Zhou P, Creer MH, Piwnica-Worms D, Nolta JA. Fluorophore-conjugated iron oxide nanoparticle labeling and analysis of engrafting human hematopoietic stem cells. Stem Cells 2007; 26:517-24. [PMID: 18055451 DOI: 10.1634/stemcells.2007-0016] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The use of nanometer-sized iron oxide particles combined with molecular imaging techniques enables dynamic studies of homing and trafficking of human hematopoietic stem cells (HSC). Identifying clinically applicable strategies for loading nanoparticles into primitive HSC requires strictly defined culture conditions to maintain viability without inducing terminal differentiation. In the current study, fluorescent molecules were covalently linked to dextran-coated iron oxide nanoparticles (Feridex) to characterize human HSC labeling to monitor the engraftment process. Conjugating fluorophores to the dextran coat for fluorescence-activated cell sorting purification eliminated spurious signals from nonsequestered nanoparticle contaminants. A short-term defined incubation strategy was developed that allowed efficient labeling of both quiescent and cycling HSC, with no discernable toxicity in vitro or in vivo. Transplantation of purified primary human cord blood lineage-depleted and CD34(+) cells into immunodeficient mice allowed detection of labeled human HSC in the recipient bones. Flow cytometry was used to precisely quantitate the cell populations that had sequestered the nanoparticles and to follow their fate post-transplantation. Flow cytometry endpoint analysis confirmed the presence of nanoparticle-labeled human stem cells in the marrow. The use of fluorophore-labeled iron oxide nanoparticles for fluorescence imaging in combination with flow cytometry allows evaluation of labeling efficiencies and homing capabilities of defined human HSC subsets.
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Affiliation(s)
- Dustin J Maxwell
- Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri, USA
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