ORCID Profile
0000-0002-7299-6025
Current Organisation
Mater Research Institute The University of Queensland
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Cellular Interactions (incl. Adhesion, Matrix, Cell Wall) | Infectious Agents | Animal Physiology - Cell | Biochemistry and Cell Biology | Cell Development, Proliferation and Death |
Skeletal System and Disorders (incl. Arthritis) | Skin and Related Disorders | Cancer and Related Disorders | Immune System and Allergy | Infectious Diseases
Publisher: Springer Science and Business Media LLC
Date: 02-03-2017
Abstract: Current in vivo models for investigating human primary bone tumors and cancer metastasis to the bone rely on the injection of human cancer cells into the mouse skeleton. This approach does not mimic species-specific mechanisms occurring in human diseases and may preclude successful clinical translation. We have developed a protocol to engineer humanized bone within immunodeficient hosts, which can be adapted to study the interactions between human cancer cells and a humanized bone microenvironment in vivo. A researcher trained in the principles of tissue engineering will be able to execute the protocol and yield study results within 4-6 months. Additive biomanufactured scaffolds seeded and cultured with human bone-forming cells are implanted ectopically in combination with osteogenic factors into mice to generate a physiological bone 'organ', which is partially humanized. The model comprises human bone cells and secreted extracellular matrix (ECM) however, other components of the engineered tissue, such as the vasculature, are of murine origin. The model can be further humanized through the engraftment of human hematopoietic stem cells (HSCs) that can lead to human hematopoiesis within the murine host. The humanized organ bone model has been well characterized and validated and allows dissection of some of the mechanisms of the bone metastatic processes in prostate and breast cancer.
Publisher: Springer Berlin Heidelberg
Date: 2007
DOI: 10.1007/978-3-540-68976-8_1
Abstract: Bone marrow (BM) is a source of various stem and progenitor cells in the adult, and it is able to regenerate a variety of tissues following transplantation. In the 1970s the first BM stem cells identified were hematopoietic stem cells (HSCs). HSCs have the potential to differentiate into all myeloid (including erythroid) and lymphoid cell lineages in vitro and reconstitute the entire hematopoietic and immune systems following transplantation in vivo. More recently, nonhematopoietic stem and progenitor cells have been identified that can differentiate into other cell types such as endothelial progenitor cells (EPCs), contributing to the neovascularization of tumors as well as ischemic tissues, and mesenchymal stem cells (MSCs), which are able to differentiate into many cells of ectodermal, endodermal, and mesodermal origins in vitro as well as in vivo. Following adequate stimulation, stem and progenitor cells can be forced out of the BM to circulate into the peripheral blood, a phenomenon called "mobilization." This chapter reviews the molecular mechanisms behind mobilization and how these have led to the various strategies employed to mobilize BM-derived stem and progenitor cells in experimental and clinical settings. Mobilization of HSCs will be reviewed first, as it has been best-explored--being used extensively in clinics to transplant large numbers of HSCs to rescue cancer patients requiring hematopoietic reconstitution--and provides a paradigm that can be generalized to the mobilization of other types of BM-derived stem and progenitor cells in order to repair other tissues.
Publisher: Wiley
Date: 13-12-2022
DOI: 10.1002/JBMR.4482
Abstract: Neurogenic heterotopic ossifications (NHOs) form in periarticular muscles after severe spinal cord (SCI) and traumatic brain injuries. The pathogenesis of NHO is poorly understood with no effective preventive treatment. The only curative treatment remains surgical resection of pathological NHOs. In a mouse model of SCI‐induced NHO that involves a transection of the spinal cord combined with a muscle injury, a differential gene expression analysis revealed that genes involved in inflammation such as interleukin‐1β (IL‐1β) were overexpressed in muscles developing NHO. Using mice knocked‐out for the gene encoding IL‐1 receptor (IL1R1) and neutralizing antibodies for IL‐1α and IL‐1β, we show that IL‐1 signaling contributes to NHO development after SCI in mice. Interestingly, other proteins involved in inflammation that were also overexpressed in muscles developing NHO, such as colony‐stimulating factor‐1, tumor necrosis factor, or C‐C chemokine ligand‐2, did not promote NHO development. Finally, using NHO biopsies from SCI and TBI patients, we show that IL‐1β is expressed by CD68 + macrophages. IL‐1α and IL‐1β produced by activated human monocytes promote calcium mineralization and RUNX2 expression in fibro‐adipogenic progenitors isolated from muscles surrounding NHOs. Altogether, these data suggest that interleukin‐1 promotes NHO development in both humans and mice. © 2021 American Society for Bone and Mineral Research (ASBMR).
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.SEMCDB.2016.08.009
Abstract: Macrophages, named for their phagocytic ability, participate in homeostasis, tissue regeneration and inflammatory responses. Bone and adjacent marrow contain multiple functionally unique resident tissue macrophage subsets which maintain and regulate anatomically distinct niche environments within these interconnected tissues. Three subsets of bone-bone marrow resident tissue macrophages have been characterised erythroblastic island macrophages, haematopoietic stem cell niche macrophages and osteal macrophages. The role of these macrophages in controlling homeostasis and repair in bone and bone marrow niches is reviewed in detail.
Publisher: Humana Press
Date: 21-12-2011
DOI: 10.1007/978-1-61779-527-5_3
Abstract: The hematopoietic system is highly proliferative in the bone marrow (BM) due to the short half-life of granulocytes and platelets in the blood. Analysis of cell cycling and cell proliferation in vivo in specific populations of the mouse BM has highlighted some key properties of adult hematopoietic stem cells (HSCs). For instance, despite their enormous proliferation and repopulation potential, most true HSC are deeply quiescent in G(0) phase of the cell cycle and ide very infrequently, while less potent lineage-restricted progenitors ide rapidly to replace the daily consumption of blood leukocytes, erythrocytes, and platelets. In response to stress, e.g., following ablative chemotherapy or irradiation, HSC must enter the cell cycle to rapidly repopulate the BM with progenitors. Due to their extreme rarity in the BM, at least five color flow cytometry for cell surface antigens has to be combined with staining for DNA content and nuclear markers of proliferation to analyze cell cycle and proliferation of HSC in vivo. In this chapter, we describe two methods to stain mouse HSC to (1) distinguish all phases of the cell cycle (G(0), G(1), S, and G(2)/M) and (2) analyze the isional history of HSC in vivo by incorporation of the thymidine analog 5-bromo-2-deoxyuridine.
Publisher: Cold Spring Harbor Laboratory
Date: 13-09-2020
DOI: 10.1101/2020.09.13.292227
Abstract: Prior chemotherapy and/or underlying morbidity commonly leads to poor mobilisation of hematopoietic stem cells (HSC) for transplantation in cancer patients. Increasing the number of available HSC prior to mobilisation is a potential strategy to overcome this deficiency. Resident bone marrow (BM) macrophages are essential for maintenance of niches that support HSC and enable engraftment in transplant recipients. Here we examined potential of donor treatment with colony stimulating factor-1 (CSF1) to modify the BM niche and expand the potential HSC pool for autologous transplantation. We administrated CSF1 Fc fusion protein (CSF1-Fc) to naive C57Bl/6 mice and assessed the impacts on HSC number and function and overall haematopoiesis. Outcomes were assessed by in situ imaging and ex vivo flow cytometry with functional validation by colony formation and competitive transplantation assay. CSF1-Fc treatment caused a transient expansion of monocyte-macrophage cells within BM and spleen at the expense of BM B lymphopoiesis and hematopoietic stem and progenitor cell (HSPC) homeostasis. During the recovery phase after cessation of CSF1-Fc treatment, normalisation of haematopoiesis was accompanied by an increase in the total available HSPC pool. In the spleen, increased HSC was associated with expression of the BM niche marker CD169 in red pulp macrophages. Pre-treatment with CSF1-Fc increased the number and reconstitution potential of HSPC in blood following a HSC mobilising regimen of granulocyte colony stimulating factor (G-CSF) treatment. These results indicate that CSF1-Fc conditioning could represent a therapeutic strategy to overcome poor HSC mobilisation and subsequently improve autologous or heterologous HSC transplantation outcomes. 1) Recovery from Fc-modified colony stimulating factor-1 (CSF1-Fc) treatment was accompanied by an increase in total haematopoietic stem cells. 2) Pre-conditioning with CSF1-Fc increased the reconstitution potential of blood after haematopoietic stem cell mobilisation.
Publisher: Proceedings of the National Academy of Sciences
Date: 09-1986
Abstract: The possibility that the mitogenic effect of fibrinogen, a major plasma protein (3 mg/ml), is mediated by specific membrane receptors was studied. Specific binding analysis showed that fibrinogen receptors are present only on hemopoietic cell lines that respond to its mitogenic effect. The mitogenic fibrinogen receptor is not recognized by antibodies specific for the platelet fibrinogen receptor or is not competitively blocked by synthetic peptides containing the Arg-Gly-Asp sequence, which is common to fibronectin, fibrinogen, vitronectin, and other cell-attachment proteins. The lymphoma-derived pre-B-cells (Raji) have 149,000 receptors, whereas the lymphoma-derived T cells (JM), which are 3 times smaller, have 54,000 receptors. These receptors have a Kd of 2 X 10(-7) M. They are inducible by stimuli specific for the cell lineage: activators of the breakdown of phosphatidylinositol phosphates, such as platelet activating factor for Raji cells, and adenylate cyclase agonists and cAMP analogues for JM cells. The stimuli have no mitogenic effect in the absence of fibrinogen they do not change the Kd. Each stimulus increases the number of fibrinogen receptors in a dose-dependent manner, which correlates strongly (r = -0.98, n = 5) with an increased growth rate of cells in the presence of fibrinogen. This correlation concludes that the mitogenic effect of fibrinogen is controlled via receptor modulation.
Publisher: Humana Press
Date: 21-12-2012
DOI: 10.1007/978-1-61779-527-5_4
Abstract: Identification of the precise location, where hematopoietic stem cells (HSCs) reside in the bone marrow, has made a great leap forward with the advance of live time-lapse video 2-photon fluorescent microscopy. These studies have shown that HSCs preferentially resides in the endosteal region of the BM, at an average of two cell diameters from osteoblasts covering endosteal bone surfaces. However, this equipment is very sophisticated and only a very few laboratories can perform these studies. To investigate functional attributes of these niches, we have developed a flow cytometry technique in which mice are perfused with the cell-permeable fluorescent dye Hoechst33342 in vivo before bone marrow cells are collected and antibody stained. This method enables to position phenotypic HSC, multipotent and myeloid progenitors, as well as BM nonhematopoietic stromal cells relative to blood flow in vivo. This technique enables prospective isolation of HSCs based on the in vivo perfusion of the niches in which they reside.
Publisher: Springer Science and Business Media LLC
Date: 13-09-2022
DOI: 10.1038/S41375-021-01413-Z
Abstract: We show that pro-inflammatory oncostatin M (OSM) is an important regulator of hematopoietic stem cell (HSC) niches in the bone marrow (BM). Treatment of healthy humans and mice with granulocyte colony-stimulating factor (G-CSF) dramatically increases OSM release in blood and BM. Using mice null for the OSM receptor (OSMR) gene, we demonstrate that OSM provides a negative feed-back acting as a brake on HSPC mobilization in response to clinically relevant mobilizing molecules G-CSF and CXCR4 antagonist. Likewise, injection of a recombinant OSM molecular trap made of OSMR complex extracellular domains enhances HSC mobilization in poor mobilizing C57BL/6 and NOD.Cg-Prkdc
Publisher: Elsevier BV
Date: 02-2005
DOI: 10.1016/J.EXPHEM.2004.10.018
Abstract: The two endothelial selectins, P- and E-selectin, are critically important for adhesion and homing of hematopoietic progenitor cells (HPC) into the bone marrow. Little is known, however, about the roles of these two selectins in hematopoiesis. Here, we demonstrate that the most primitive HPC capable of long-term in vivo repopulation express P-selectin glycoprotein ligand-1/CD162 (PSGL-1), a receptor common to both P- and E-selectin. In addition, we demonstrate that P-selectin delays the differentiation of HPC whereas E-selectin enhances their differentiation along the monocyte/granulocyte pathway, describing different roles for these selectins in the regulation of hematopoiesis. Murine bone marrow HPC were isolated according to their expression of c-kit and PSGL-1, transplanted into lethally irradiated congenic recipients, and chimerism analyzed 6 months posttransplant. Bone marrow lineage-negative (Lin(-)) Sca-1(+)c-kit(+) cells were then cultured on immobilized P- or E-selectin for 4 weeks in the presence of cytokines. Hematopoietic potential was assessed using in vitro phenotyping and colony-forming assays and in vivo spleen colony-forming unit (CFU-S) and long-term competitive repopulation assays. Long-term competitive repopulating HSCs were Lin(-)c-kit(bright) and expressed intermediate levels of PSGL-1. Both P- and E-selectin slowed the proliferation of Lin(-)Sca-1(+)c-kit(+) cells during the first two weeks of liquid culture. After two weeks, however, cells cultured on immobilized P-selectin showed increased proliferation with increased production of both colony-forming cells (CFC) and CFU-S(12) compared to the other cultures. In contrast, E-selectin enhanced the differentiation of Lin(-)Sca-1(+)c-kit(+) cells into cells that expressed the granulocyte maturation marker, Gr-1, accompanied by loss of CFC potential from these cultured cells. Finally, the long-term repopulation potential of these cells was not maintained following culture on either selectin. These results suggest that the two endothelial selectins, E-selectin and P-selectin, have very different effects on HPC. E-selectin accelerates the differentiation of maturing HPC towards granulocyte and monocyte lineages while maintaining the production of more immature CFU-S(12) in ex vivo liquid suspension culture. In marked contrast, P-selectin delays the differentiation of Lin(-)Sca-1(+)c-kit(+) cells, allowing enhanced ex vivo expansion of CFC and CFU-S(12) but not HSCs.
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.BIOMATERIALS.2015.04.057
Abstract: Advances in tissue-engineering have resulted in a versatile tool-box to specifically design a tailored microenvironment for hematopoietic stem cells (HSCs) in order to study diseases that develop within this setting. However, most current in vivo models fail to recapitulate the biological processes seen in humans. Here we describe a highly reproducible method to engineer humanized bone constructs that are able to recapitulate the morphological features and biological functions of the HSC niches. Ectopic implantation of biodegradable composite scaffolds cultured for 4 weeks with human mesenchymal progenitor cells and loaded with rhBMP-7 resulted in the development of a chimeric bone organ including a large number of human mesenchymal cells which were shown to be metabolically active and capable of establishing a humanized microenvironment supportive of the homing and maintenance of human HSCs. A syngeneic mouse-to-mouse transplantation assay was used to prove the functionality of the tissue-engineered ossicles. We predict that the ability to tissue engineer a morphologically intact and functional large-volume bone organ with a humanized bone marrow compartment will help to further elucidate physiological or pathological interactions between human HSCs and their native niches.
Publisher: Elsevier BV
Date: 04-1999
DOI: 10.1016/S0301-472X(98)00069-1
Abstract: Significant progress has been made recently in the understanding of cell adhesion signaling. Many components of focal adhesion complexes have been identified in fibroblasts and endothelial cells, showing considerable overlap and complementarity between growth signaling mediated by growth factor receptors and adhesive signaling mediated by cell adhesion receptors such as integrins. These studies showed that the cytoskeleton is essential for the correct intracellular localization of large signaling complexes that regulate the cellular machinery. Although adhesive interactions are essential to maintain steady-state hemopoiesis, the study of the function and role of adhesive interactions in hemopoietic progenitor and stem cells is less advanced. As in fibroblasts, functional overlap between hemopoietic growth factor receptors and cell adhesion receptors has been demonstrated, with the cytoskeleton likely playing a critical role in integrating information provided by soluble factors and cell adhesion molecules constituting the hemopoietic microenvironment. The intention of this article is to give a critical review of the current knowledge about the cytoskeleton and integrin-mediated signaling in hemopoietic progenitor cells.
Publisher: Rockefeller University Press
Date: 05-1995
Abstract: Cytokines are known to be important regulators of normal hemopoiesis, acting in concert with components of the bone marrow microenvironment. Interactions with this microenvironment are known to regulate the proliferation, differentiation, and homing of hemopoietic progenitor (CD34+) cells. Adhesive interactions with the extracellular matrix retain CD34+ cells in close proximity to cytokines, but may also provide important costimulatory signals. Thus, the functional states of adhesion receptors are critical properties of CD34+ cells, but the physiological mechanisms responsible for regulating functional properties of cell adhesion receptors on primitive hemopoietic cells are still unknown. We confirm that the integrins very late antigen (VLA)-4 and VLA-5 are expressed on the CD34+ cell lines MO7e, TF1, and on normal bone marrow CD34+ progenitor cells, but in a low affinity state, conferring on them a weak adhesive phenotype on fibronectin (Fn). Herein, we show that the cytokines interleukin (IL)-3, granulocyte-macrophage CSF (GM-CSF), and KIT ligand (KL) are physiological activators of VLA-4 and VLA-5 expressed by MO7e, TF1, and normal bone marrow CD34+ progenitor cells. Cytokine-stimulated adhesion on Fn is dose dependent and transient, reaching a maximum between 15 and 30 min and returning to basal levels after 2 h. This cytokine-dependent activation is specific for VLA-4 and VLA-5, since activation of other beta 1 integrins was not observed. The addition of second messenger antagonists staurosporine and W7 abolished all cytokine-stimulated adhesion to Fn. In contrast, genistein inhibited KL-stimulated adhesion, but failed to inhibit GM-CSF- and IL-3-stimulated adhesion. Our data suggest that cytokines GM-CSF and IL-3 specifically stimulate beta 1 integrin function via an "inside-out" mechanism involving protein kinase activity, while KL stimulates integrin activity through a similar, but initially distinct, pathway via the KIT tyrosine-kinase. Thus, in addition to promoting the survival, proliferation, and development of hemopoietic progenitors, cytokines also regulate adhesive interactions between progenitor cells and the bone marrow microenvironment by modifying the functional states of specific integrins. These data are of importance in understanding the fundamental processes of beta 1 integrin activation and cellular response to mitogenic cytokines as well as on the clinical setting where cytokines induce therapeutic mobilization of hematopoietic progenitors.
Publisher: Elsevier BV
Date: 1987
DOI: 10.1016/S0769-2625(87)80055-7
Abstract: In a defined medium in which transferrin (3 micrograms/ml) was the only source of exogenous proteins, Raji cells of the human pre-B lymphoblastoid cell line died within 48 h after forming polykaryons. The simple addition of purified C3 at a concentration equal to or higher than 3 micrograms/ml allowed Raji cells to ide. This preliminary report provides a defined system for studying the mitogenic effect of human C3 or C3 fragments upon proliferation of human B-cells lines.
Publisher: Wiley
Date: 06-1998
Publisher: Wiley
Date: 08-1987
Abstract: We have previously established that the mitogenic effect of fibrinogen on hemopoietic cell lines Raji and JM is mediated via a specific receptor (Levesque, J.-P. et al.: Proc. Natl. Acad. Sci. USA 83:6494-6498, 1986). In this study, we have further characterized the fibrinogen domain involved in the binding to the mitogenic receptor. This binding was not inhibited either by a monoclonal antibody against the C-terminal sequence of the fibrinogen gamma chains or by synthetic peptides containing the Arg-Gly-Asp sequence. Such inhibition is specific of the platelet fibrinogen receptor, the glycoprotein IIb-IIIa complex. Fragments containing the fibrinogen D domain were the only plasmin degradation products of fibrinogen which were mitogenic. These fragments acted via direct binding on the mitogenic receptor with a Kd of 2.24 X 10(-6) M. This value was similar to the KI value of unlabeled fragments D (2.47 X 10(-6) M). Our results suggest the presence of two different functional types of fibrinogen receptors: the glycoprotein IIb-IIIa receptor responsible both for platelet aggregation and leukocyte adhesion and killing, and the mitogenic receptor involved in proliferation control of hemopoietic cells.
Publisher: Elsevier BV
Date: 03-2016
DOI: 10.1016/J.EXPHEM.2015.11.004
Abstract: The cytokines granulocyte colony-stimulating factor (G-CSF) and Flt3 ligand (Flt3-L) mobilize hematopoietic stem and progenitor cells into the peripheral blood of primates, humans, and mice. We recently reported that G-CSF administration causes a transient blockade of medullar erythropoiesis by suppressing erythroblastic island (EI) macrophages in the bone marrow. In the study described here, we investigated the effect of mobilizing doses of Flt3-L on erythropoiesis in mice in vivo. Similar to G-CSF, Flt3-L caused whitening of the bone marrow with significant reduction in the numbers of EI macrophages and erythroblasts. This was compensated by an increase in the numbers of EI macrophages and erythroblasts in the spleen. However, unlike G-CSF, Flt3-L had an indirect effect on EI macrophages, as it was not detected at the surface of EI macrophages or erythroid progenitors.
Publisher: American Society of Hematology
Date: 02-12-2010
DOI: 10.1182/BLOOD-2009-11-253534
Abstract: In the bone marrow, hematopoietic stem cells (HSCs) reside in specific niches near osteoblast-lineage cells at the endosteum. To investigate the regulation of these endosteal niches, we studied the mobilization of HSCs into the bloodstream in response to granulocyte colony-stimulating factor (G-CSF). We report that G-CSF mobilization rapidly depletes endosteal osteoblasts, leading to suppressed endosteal bone formation and decreased expression of factors required for HSC retention and self-renewal. Importantly, G-CSF administration also depleted a population of trophic endosteal macrophages (osteomacs) that support osteoblast function. Osteomac loss, osteoblast suppression, and HSC mobilization occurred concomitantly, suggesting that osteomac loss could disrupt endosteal niches. Indeed, in vivo depletion of macrophages, in either macrophage Fas-induced apoptosis (Mafia) transgenic mice or by administration of clodronate-loaded liposomes to wild-type mice, recapitulated the: (1) loss of endosteal osteoblasts and (2) marked reduction of HSC-trophic cytokines at the endosteum, with (3) HSC mobilization into the blood, as observed during G-CSF administration. Together, these results establish that bone marrow macrophages are pivotal to maintain the endosteal HSC niche and that the loss of such macrophages leads to the egress of HSCs into the blood.
Publisher: Mary Ann Liebert Inc
Date: 08-2002
DOI: 10.1089/153685902760213868
Abstract: Cell adhesion receptors of the integrin superfamily can be expressed in different affinity states towards their ligands. It has been previously demonstrated that beta(1) integrins alpha4beta(1) and alpha5beta(1) are expressed in a nonligand binding form by human hemopoietic progenitor cells but can be activated into a ligand binding form by a variety of stimuli including intracellular stimuli generated by cytokine receptors and extracellular stimuli generated by function-activating anti-beta(1) integrin monoclonal antibodies (MAbs). In both instances, the activation of beta(1) integrins is believed to be the result of conformational changes propagating along the beta(1) integrin chain which in turn increase accessibility to the ligand. A cluster of either function-activating or function-inhibiting anti-beta(1) integrin MAbs have been shown to bind within a 12 amino acid long regulatory loop between residues 207 and 218 of the human beta(1) integrin chain. We describe in this report the first MAb (96.9H9) specific for this regulatory loop whose binding is cation-dependent and requires either Ca(2+) or Mn(2+) but not Mg(2+). In addition, the activation of alpha4beta(1) and alpha5beta(1) integrins by 96.9H9 is a two-step process with distinct cation requirements. Whereas Ca(2+) is sufficient to promote binding of the antibody to the beta(1) integrin chain, Mg(2+) is necessary for activating function following 96.9H9 binding. Our data therefore suggest that the regulatory epitope of the human beta(1) integrin chain is flexible with multiple conformations according to the cationic environment.
Publisher: American Society of Hematology
Date: 15-08-1996
DOI: 10.1182/BLOOD.V88.4.1168.BLOODJOURNAL8841168
Abstract: Adhesive interactions with the extracellular matrix of the bone marrow (BM) stroma are of critical importance in the regulation of hematopoiesis. In part, these interactions are presumed to play an important role in retaining CD34+ hematopoietic progenitor cells (HPCs) within the BM environment, in close proximity with BM stromal cells and the cytokines they produce. Evidence of a more direct role for cell adhesion in the regulation of hematopoiesis is provided by recent data showing that adhesive interactions can also provide important costimulatory signals. We have previously shown that normal CD34+ HPCs express high levels of fibronectin (Fn) receptors very late antigen-4 (VLA-4) and VLA-5 in a low-affinity state, which do not allow HPCs to strongly adhere on immobilized Fn, and that cytokines such as interleukin-3, granulocyte-monocyte colony-stimulating factor, and stem cell factor transiently activate these receptors, providing HPCs with an adhesive phenotype on Fn. Thus, knowledge of the functional states of adhesion receptors is critical to our understanding of the physiological mechanisms responsible for the regulation of normal hematopoiesis. Herein, we show that combinations of cytokines that synergize to stimulate the proliferation of CD34+ HPCs result in additive stimulation of the adhesion of these cells to Fn. Thus, the activation level of Fn receptors expressed by normal CD34+ HPCs is highly correlated with their proliferative state, suggesting a functional link between these two events. Therefore, we propose a 2- step model with an initial activation of VLA-4 and VLA-5 generated by cytokine receptors that is followed by a secondary signal resulting from Fn binding to VLA-4 and VLA-5, which may cooperate with those generated by cytokine receptors.
Publisher: Wiley
Date: 23-02-2005
DOI: 10.1111/J.1399-0039.2005.00358.X
Abstract: Endolyn (CD164) is a sialomucin that functions as an adhesion molecule and a negative regulator of CD34+ CD38- human haematopoietic precursor cell proliferation. The 105A5 and 103B2/9E10 CD164 monoclonal antibodies (mAbs), which act as surrogate ligands, recognize distinct glycosylation-dependent classes I and II epitopes located on domain I of the native and recombinant CD164 proteins. Here, we document five new CD164 mAbs, the 96 series, that rely on conformational integrity, but not glycosylation, of exons 2- and 3-encoded CD164 domains, thereby resembling the class III mAbs, N6B6 and 67D2. Although all the 96 series class III mAbs labelled both the 105A5+ and 103B2/9E10+ cells, cross-competition and immunoblotting studies allow them to be categorized into two distinct class III subgroups, i.e. the N6B6-like subgroup that only recognizes 80-100 kDa proteins and the 67D2-like subgroup that also recognizes a higher molecular weight (>220 kDa) form. To more closely define the reactivity patterns of mAbs to the classes I and II epitopes, the global glycosylation patterns of the soluble human (h) CD164 proteins were determined using lectin binding, high-performance liquid chromatography (HPLC) and mass spectrometry. hCD164 recombinant proteins bound to the lectins, Galanthus nivalis agglutinin, Datura stramonium agglutinin, Sambucus nigra agglutinin, Maackia amurensis agglutinin and peanut agglutinin, indicating the presence of high mannose and complex N-glycans, in addition to core 1 O-glycans (the Tn antigen) and alpha2-3 and alpha2-6 sialic acid moieties. Our HPLC and mass spectrometry results revealed both high mannose and complex N-glycosylation with various numbers of branches increasing the complexity of the glycosylation pattern. Most O-glycans were small, core 1 or 2 based. High levels of sialylation in alpha2-3 and alpha2-6 linkages, without sialyl-Lewis X, indicate that the majority of these hCD164 recombinant proteins are unable to bind to selectins in our assay system, but may interact with Siglec molecules.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.BIOMATERIALS.2017.10.033
Abstract: Osteal macrophages (osteomacs) contribute to bone homeostasis and regeneration. To further distinguish their functions from osteoclasts, which share many markers and growth factor requirements, we developed a rapid, enzyme-free osteomac enrichment protocol that permitted characterization of minimally manipulated osteomacs by flow cytometry. Osteomacs differ from osteoclasts in expression of Siglec1 (CD169). This distinction was confirmed using the CD169-diphtheria toxin (DT) receptor (DTR) knock-in model. DT treatment of naïve CD169-DTR mice resulted in selective and striking loss of osteomacs, whilst osteoclasts and trabecular bone area were unaffected. Consistent with a previously-reported trophic interaction, osteomac loss was accompanied by a concomitant and proportionately striking reduction in osteoblasts. The impact of CD169
Publisher: Springer Science and Business Media LLC
Date: 13-10-2016
Publisher: Springer Science and Business Media LLC
Date: 21-10-2012
DOI: 10.1038/NM.2969
Abstract: The microenvironment, or niche, surrounding a stem cell largely governs its cellular fate. Two anatomical niches for hematopoietic stem cells (HSCs) have been reported in the bone marrow, but a distinct function for each of these niches remains unclear. Here we report a new role for the adhesion molecule E-selectin expressed exclusively by bone marrow endothelial cells in the vascular HSC niche. HSC quiescence was enhanced and self-renewal potential was increased in E-selectin knockout (Sele(-/-)) mice or after administration of an E-selectin antagonist, demonstrating that E-selectin promotes HSC proliferation and is a crucial component of the vascular niche. These effects are not mediated by canonical E-selectin ligands. Deletion or blockade of E-selectin enhances HSC survival threefold to sixfold after treatment of mice with chemotherapeutic agents or irradiation and accelerates blood neutrophil recovery. As bone marrow suppression is a severe side effect of high-dose chemotherapy, transient blockade of E-selectin is potentially a promising treatment for the protection of HSCs during chemotherapy or irradiation.
Publisher: Wiley
Date: 20-01-2011
DOI: 10.1002/JBMR.334
Publisher: Wiley
Date: 05-1993
Abstract: We have previously shown (Zhou et al: Blood, 72:1870, 1988) that IL3, added with low concentrations of CSF-1 (1 ng/ml) to normal human CD34+ enriched cells, promoted the development of various types of colonies including those containing immature monocytes. However, when high concentrations of CSF-1 (20 ng/ml) were added alone or together with IL3, smaller colonies with mature macrophages were found. Here we show by in situ hybridization that IL3 allows the development, from CD34+ cells, of a subpopulation of immature progenitors which express the CSF-1 receptor (c-fms) mRNA. The expression of c-FMS protein was also substantiated by immunocytochemical studies using anti-c-fms antibody. The percentage of c-fms positive cells peaked at day 7 and began to decrease thereafter. When anti-CSF-1 antibodies were included in the culture, the decrease in c-fms mRNA after day 7 was abrogated. This indicated that endogenous CSF-1 was produced as CD34+ cells developed into monocytes or progenitors of monocytes and that CSF-1 modulates c-fms expression. We further demonstrated that when a high dose of CSF-1 (20 ng/ml) was added at day 7 to IL3-stimulated CD34+ cells, a rapid down-regulation of c-fms mRNA and protein was seen. No down-regulation was observed with low concentration of CSF-1 (1 ng/ml). The possibility that different concentrations of CSF-1 could modulate the development of monocytic progenitors is discussed.
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.EXPHEM.2014.03.009
Abstract: Similarly to other tissues, the bone marrow contains subsets of resident tissue macrophages, which are essential to maintain bone formation, functional hematopoietic stem cell (HSC) niches, and erythropoiesis. Pharmacologic doses of granulocyte colony-stimulating factor (G-CSF) mobilize HSC in part by interfering with the HSC niche-supportive function of BM resident macrophages. Because bone marrow macrophages are key to both maintenance of HSC within their niche and erythropoiesis, we investigated the effect of mobilizing doses of G-CSF on erythropoiesis in mice. We now report that G-CSF blocks medullar erythropoiesis by depleting the erythroid island macrophages we identified as co-expressing F4/80, vascular cell adhesion molecule-1, CD169, Ly-6G, and the ER-HR3 erythroid island macrophage antigen. Both broad macrophage depletion, achieved by injecting clodronate-loaded liposomes, and selective depletion of CD169(+) macrophages, also concomitantly depleted F4/80(+)VCAM-1(+)CD169(+)ER-HR3(+)Ly-6G(+) erythroid island macrophages and blocked erythropoiesis. This more precise phenotypic definition of erythroid island macrophages will enable studies on their biology and function in normal settings and on diseases associated with anemia. Finally, this study further illustrates that macrophages are a potent relay of innate immunity and inflammation on bone, hematopoietic, and erythropoietic maintenance. Agents that affect these macrophages, such as G-CSF, are likely to affect these three processes concomitantly.
Publisher: EDP Sciences
Date: 03-2013
Publisher: Wiley
Date: 08-2011
DOI: 10.1111/J.1445-5994.2011.02544.X
Abstract: Mobilization and collection of haemopoietic stem and progenitor cells (HSPC) is the cornerstone of autologous and allogeneic stem cell transplantation for a wide variety of haematological and some non-haematological malignancies. Centres providing this service face the challenge of optimizing the likelihood of successful collection of transplantable doses of cells, while maximizing the efficiency of the apheresis unit and minimizing the risk of toxicity as well as mobilization failure. Recent developments in the understanding of the molecular mechanisms of mobilization have led to the emergence of novel strategies for HSPC mobilization, which may assist in meeting these imperatives. The task for clinicians is how to incorporate the use of these strategies into practice, in the light of emerging evidence for efficacy and safety of these agents. Herein, the literature is reviewed, and a proposed algorithm for HSPC mobilization is presented.
Publisher: American Society of Hematology
Date: 09-2001
Abstract: Mobilized progenitor cells currently represent the most commonly used source of hematopoietic progenitor cells (HPCs) to effect hematopoietic reconstitution following myeloablative chemotherapies. Despite their widespread use, the molecular mechanisms responsible for the enforced egress of HPCs from the bone marrow (BM) into the circulation in response to mobilizing agents such as cytokines remain to be determined. Results of this study indicate that expression of vascular cell adhesion molecule-1 (VCAM-1) is strongly reduced in vivo in the BM during HPC mobilization by granulocyte colony-stimulating factor (G-CSF) and stem cell factor. Two serine proteases, namely, neutrophil elastase and cathepsin G, were identified, which cleave VCAM-1 and are released by neutrophils accumulating in the BM during the course of immobilization induced by G-CSF. The proposal is made that an essential step contributing to the mobilization of HPCs is the proteolytic cleavage of VCAM-1 expressed by BM stromal cells, an event triggered by the degranulation of neutrophils accumulating in the BM in response to the administration of G-CSF.
Publisher: American Society for Clinical Investigation
Date: 02-05-2019
Publisher: Rockefeller University Press
Date: 28-03-2005
DOI: 10.1084/JEM.20042299
Abstract: Mobilization of hematopoietic progenitor cells into the blood involves a massive release of neutrophil serine proteases in the bone marrow. We hypothesize that the activity of these neutrophil serine proteases is regulated by the expression of naturally occurring inhibitors (serpina1 and serpina3) produced locally within the bone marrow. We found that serpina1 and serpina3 were transcribed in the bone marrow by many different hematopoietic cell populations and that a strong reduction in expression occurred both at the protein and mRNA levels during mobilization induced by granulocyte colony-stimulating factor or chemotherapy. This decreased expression was restricted to the bone marrow as serpina1 expression was maintained in the liver, leading to no change in plasma concentrations during mobilization. The down-regulation of serpina1 and serpina3 during mobilization may contribute to a shift in the balance between serine proteases and their inhibitors, and an accumulation of active neutrophil serine proteases in bone marrow extravascular fluids that cleave and inactivate molecules essential to the retention of hematopoietic progenitor cells within the bone marrow. These data suggest an unexpected role for serpina1 and serpina3 in regulating the bone marrow hematopoietic microenvironment as well as influencing the migratory behavior of hematopoietic precursors.
Publisher: Frontiers Media SA
Date: 05-03-2021
DOI: 10.3389/FCELL.2021.611842
Abstract: Hematopoiesis and bone interact in various developmental and pathological processes. Neurogenic heterotopic ossifications (NHO) are the formation of ectopic hematopoietic bones in peri-articular muscles that develop following severe lesions of the central nervous system such as traumatic cerebral or spinal injuries or strokes. This review will focus on the hematopoietic facet of NHO. The characterization of NHO demonstrates the presence of hematopoietic marrow in which quiescent hematopoietic stem cells (HSC) are maintained by a functional stromal microenvironment, thus documenting that NHOs are neo-formed ectopic HSC niches. Similarly to adult bone marrow, the NHO permissive environment supports HSC maintenance, proliferation and differentiation through bidirectional signaling with mesenchymal stromal cells and endothelial cells, involving cell adhesion molecules, membrane-bound growth factors, hormones, and secreted matrix proteins. The participation of the nervous system, macrophages and inflammatory cytokines including oncostatin M and transforming growth factor (TGF)-β in this process, reveals how neural circuitry fine-tunes the inflammatory response to generate hematopoietic bones in injured muscles. The localization of NHOs in the peri-articular muscle environment also suggests a role of muscle mesenchymal cells and bone metabolism in development of hematopoiesis in adults. Little is known about the establishment of bone marrow niches and the regulation of HSC cycling during fetal development. Similarities between NHO and development of fetal bones make NHOs an interesting model to study the establishment of bone marrow hematopoiesis during development. Conversely, identification of stage-specific factors that specify HSC developmental state during fetal bone development will give more mechanistic insights into NHO.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2016
Publisher: Elsevier BV
Date: 02-2003
DOI: 10.1016/S0301-472X(02)01028-7
Abstract: Administration of granulocyte colony-stimulating factor (G-CSF) results in the mobilization of hematopoietic progenitor and stem cells from the bone marrow into the peripheral blood. Although the mechanisms leading to the mobilization of primitive hematopoietic cells is not fully understood, it has been noted that the yield of mobilization in humans is correlated to the down-regulation of c-KIT/CD117 expression on mobilized cells. We sought to determine the mechanisms responsible for the reduced expression of c-KIT on mobilized hematopoietic progenitor cells. Mice were mobilized with G-CSF and primitive hematopoietic cells were collected from bone marrow and blood to analyze c-KIT expression. Using cell lines expressing mouse and human c-KIT and a recombinant protein comprising the entire extracellular domain of human c-KIT, we analyzed by flow cytometry and immunoblotting the proteolytic cleavage of c-KIT by proteases released in bone marrow extracellular fluids extracted from mobilized mice. Administration of G-CSF into mice results in the reduction of c-KIT expression on primitive hematopoietic cells in bone marrow and peripheral blood. Bone marrow extracellular fluids isolated from G-CSF-mobilized mice contain serine proteases that cleave c-KIT into discrete fragments. Proteases capable of cleaving c-KIT include neutrophil elastase, cathepsin G, proteinase-3 and matrix metalloproteinase-9. In addition to transcriptional controls, exocytosis, and ligand-induced internalization, the direct proteolytic cleavage of c-KIT by neutrophil and macrophage proteases represents a novel pathway to regulate the levels of c-KIT expression at the surface of hematopoietic cells and may be responsible in part for the down-regulation of c-KIT expression on mobilized hematopoietic progenitors in vivo.
Publisher: Wiley
Date: 17-09-2020
DOI: 10.1002/JBMR.4118
Publisher: American Society of Hematology
Date: 11-04-2013
DOI: 10.1182/BLOOD-2013-02-485144
Abstract: In this issue of Blood, Corselli et al purify CD1461 pericytes from human adipose or fetal bone marrow and demonstrate that these cells are capable of supporting the self-renewal and proliferation of transplantable human cord blood hematopoietic stem cells (HSCs).
Publisher: Informa UK Limited
Date: 15-02-2019
Publisher: European Respiratory Society (ERS)
Date: 17-11-2022
DOI: 10.1183/13993003.01306-2022
Abstract: Severe viral respiratory infections are often characterised by extensive myeloid cell infiltration and activation and persistent lung tissue injury. However, the immunological mechanisms driving excessive inflammation in the lung remain poorly understood. To identify the mechanisms that drive immune cell recruitment in the lung during viral respiratory infections and identify novel drug targets to reduce inflammation and disease severity. Preclinical murine models of influenza A virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Oxidised cholesterols and the oxysterol-sensing receptor GPR183 were identified as drivers of monocyte/macrophage infiltration to the lung during influenza A virus (IAV) and SARS-CoV-2 infection. Both IAV and SARS-CoV-2 infection upregulated the enzymes cholesterol 25-hydroxylase (CH25H) and cytochrome P450 family 7 subfamily member B1 (CYP7B1) in the lung, resulting in local production of the oxidised cholesterols 25-hydroxycholesterol (25-OHC) and 7α,25-dihydroxycholesterol (7α,25-OHC). Loss-of-function mutation of Gpr183 or treatment with a GPR183 antagonist reduced macrophage infiltration and inflammatory cytokine production in the lungs of IAV- or SARS-CoV-2-infected mice. The GPR183 antagonist significantly attenuated the severity of SARS-CoV-2 infection and viral loads. Analysis of single-cell RNA-sequencing data on bronchoalveolar lavage s les from healthy controls and COVID-19 patients with moderate and severe disease revealed that CH25H , CYP7B1 and GPR183 are significantly upregulated in macrophages during COVID-19. This study demonstrates that oxysterols drive inflammation in the lung via GPR183 and provides the first preclinical evidence for the therapeutic benefit of targeting GPR183 during severe viral respiratory infections.
Publisher: Elsevier BV
Date: 06-1999
Publisher: Wiley
Date: 26-11-2016
Publisher: American Society of Hematology
Date: 12-1988
DOI: 10.1182/BLOOD.V72.6.1870.BLOODJOURNAL7261870
Abstract: By using human bone marrow cells enriched for early progenitors by selective immunoadsorption and plated at low cell density (10(3) to 10(4) cells/mL/9.6 cm2) in semisolid methylcellulose culture, we have analyzed the cooperative effects of human colony-stimulating factor 1 (CSF-1), granulocyte-macrophage-CSF (GM-CSF), interleukin-1 alpha (IL-1 alpha), and gibbon as well as human recombinant IL-3 on the formation of monocytic colonies. CSF-1 alone stimulated mature monocytic colony formation by human CFU-M. However, in the presence of IL-3 and erythropoietin, CSF-1 stimulated maximal immature monocytic colony formation at low concentrations and inhibited the formation of granulomonocytic, erythrocytic, and mixed colonies. Cultures with CSF-1 and IL-3 contained more immature monocytic colonies than did cultures with CSF-1 alone. IL-1 alpha alone had little effect. However, IL-1 alpha in combination with optimal concentrations of either CSF-1, GM- CSF, or IL-3 increased the number of colonies containing immature or mature monocytic colonies.
Publisher: Springer Science and Business Media LLC
Date: 23-01-2012
DOI: 10.1038/LEU.2012.17
Abstract: The CXCR4 antagonist AMD3100 is progressively replacing cyclophosphamide (CYP) as adjuvant to granulocyte colony-stimulating factor (G-CSF) to mobilize hematopoietic stem cells (HSC) for autologous transplants in patients who failed prior mobilization with G-CSF alone. It has recently emerged that G-CSF mediates HSC mobilization and inhibits bone formation via specific bone marrow (BM) macrophages. We compared the effect of these three mobilizing agents on BM macrophages, bone formation, osteoblasts, HSC niches and HSC reconstitution potential. Both G-CSF and CYP suppressed niche-supportive macrophages and osteoblasts, and inhibited expression of endosteal cytokines resulting in major impairment of HSC reconstitution potential remaining in the mobilized BM. In sharp contrast, although AMD3100 was effective at mobilizing HSC, it did not suppress osteoblasts, endosteal cytokine expression or reconstitution potential of HSC remaining in the mobilized BM. In conclusion, although G-CSF, CYP and AMD3100 efficiently mobilize HSC into the blood, their effects on HSC niches and bone formation are distinct with both G-CSF and CYP targeting HSC niche function and bone formation, whereas AMD3100 directly targets HSC without altering niche function or bone formation.
Publisher: Springer Science and Business Media LLC
Date: 12-01-2015
DOI: 10.1038/LEU.2015.8
Publisher: INIST-CNRS
Date: 1993
DOI: 10.4267/10608/2815
Publisher: Wiley
Date: 26-03-2015
DOI: 10.1002/PATH.4519
Abstract: Neurological heterotopic ossification (NHO) is the abnormal formation of bone in soft tissues as a consequence of spinal cord or traumatic brain injury. NHO causes pain, ankyloses, vascular and nerve compression and delays rehabilitation in this high-morbidity patient group. The pathological mechanisms leading to NHO remain unknown and consequently there are no therapeutic options to prevent or reduce NHO. Genetically modified mouse models of rare genetic forms of heterotopic ossification (HO) exist, but their relevance to NHO is questionable. Consequently, we developed the first model of spinal cord injury (SCI)-induced NHO in genetically unmodified mice. Formation of NHO, measured by micro-computed tomography, required the combination of both SCI and localized muscular inflammation. Our NHO model faithfully reproduced many clinical features of NHO in SCI patients and both human and mouse NHO tissues contained macrophages. Muscle-derived mesenchymal progenitors underwent osteoblast differentiation in vitro in response to serum from NHO mice without additional exogenous osteogenic stimuli. Substance P was identified as a candidate NHO systemic neuropeptide, as it was significantly elevated in the serum of NHO patients. However, antagonism of substance P receptor in our NHO model only modestly reduced the volume of NHO. In contrast, ablation of phagocytic macrophages with clodronate-loaded liposomes reduced the size of NHO by 90%, supporting the conclusion that NHO is highly dependent on inflammation and phagocytic macrophages in soft tissues. Overall, we have developed the first clinically relevant model of NHO and demonstrated that a combined insult of neurological injury and soft tissue inflammation drives NHO pathophysiology.
Publisher: Wiley
Date: 05-11-2013
Abstract: Stem cells and their malignant counterparts require the support of a specific microenvironment or "niche". While various anti-cancer therapies have been broadly successful, there are growing opportunities to target the environment in which these cells reside to further improve therapeutic efficacy and outcome. This is particularly true when the aim is to target normal or malignant stem cells. The field aiming to target or use the niches that harbor, protect, and support stem cells could be designated as "nichotherapy". In this essay, we provide a few ex les of nichotherapies. Some have been employed for decades, such as hematopoietic stem cell mobilization, whereas others are emerging, such as chemosensitization of leukemia stem cells by targeting their niche.
Publisher: Wiley
Date: 23-09-2023
DOI: 10.1002/JBMR.4905
Abstract: Neurogenic heterotopic ossifications (NHO) are heterotopic bones that develop in periarticular muscles following severe central nervous system injuries (CNS). Several retrospective studies have shown that NHO prevalence is higher in patients who suffer concomitant infections. However, it is unclear whether these infections directly contribute to NHO development or reflect the immunodepression observed in patients with CNS injury. Using our mouse model of NHO induced by spinal cord injury (SCI) between vertebrae T11‐T13, we demonstrate that lipopolysaccharides (LPS) from gram‐negative bacteria exacerbate NHO development in a toll‐like receptor‐4 (TLR4)‐dependent manner, signaling through the TIR‐domain‐containing adapter‐inducing interferon‐β (TRIF/TICAM1) adaptor rather than the myeloid differentiation primary response‐88 (MYD88) adaptor. We find that T11‐T13 SCI did not significantly alter intestinal integrity nor cause intestinal bacteria translocation or endotoxemia, suggesting that NHO development is not driven by endotoxins from the gut in this model of SCI‐induced NHO. Relevant to the human pathology, LPS increased expression of osteoblast markers in cultures of human fibro‐adipogenic progenitors isolated from muscles surrounding NHO biopsies. In a case–control retrospective study in patients with traumatic brain injuries, infections with gram‐negative Pseudomonas species were significantly associated with NHO development. Together these data suggest a functional association between gram‐negative bacterial infections and NHO development and highlights infection management as a key consideration to avoid NHO development in patients. This article is protected by copyright. All rights reserved.
Publisher: American Society of Hematology
Date: 31-01-2013
DOI: 10.1182/BLOOD-2012-02-408419
Abstract: HIF-1α protein stabilization increases HSC quiescence in vivo. HIF-1α protein stabilization increases HSC resistance to irradiation and accelerates recovery.
Publisher: Springer Science and Business Media LLC
Date: 06-01-2021
DOI: 10.1186/S13045-020-00997-W
Abstract: Prior chemotherapy and/or underlying morbidity commonly leads to poor mobilisation of hematopoietic stem cells (HSC) for transplantation in cancer patients. Increasing the number of available HSC prior to mobilisation is a potential strategy to overcome this deficiency. Resident bone marrow (BM) macrophages are essential for maintenance of niches that support HSC and enable engraftment in transplant recipients. Here we examined potential of donor treatment with modified recombinant colony-stimulating factor 1 (CSF1) to influence the HSC niche and expand the HSC pool for autologous transplantation. We administered an acute treatment regimen of CSF1 Fc fusion protein (CSF1-Fc, daily injection for 4 consecutive days) to naive C57Bl/6 mice. Treatment impacts on macrophage and HSC number, HSC function and overall hematopoiesis were assessed at both the predicted peak drug action and during post-treatment recovery. A serial treatment strategy using CSF1-Fc followed by granulocyte colony-stimulating factor (G-CSF) was used to interrogate HSC mobilisation impacts. Outcomes were assessed by in situ imaging and ex vivo standard and imaging flow cytometry with functional validation by colony formation and competitive transplantation assay. CSF1-Fc treatment caused a transient expansion of monocyte-macrophage cells within BM and spleen at the expense of BM B lymphopoiesis and hematopoietic stem and progenitor cell (HSPC) homeostasis. During the recovery phase after cessation of CSF1-Fc treatment, normalisation of hematopoiesis was accompanied by an increase in the total available HSPC pool. Multiple approaches confirmed that CD48 − CD150 + HSC do not express the CSF1 receptor, ruling out direct action of CSF1-Fc on these cells. In the spleen, increased HSC was associated with expression of the BM HSC niche macrophage marker CD169 in red pulp macrophages, suggesting elevated spleen engraftment with CD48 − CD150 + HSC was secondary to CSF1-Fc macrophage impacts. Competitive transplant assays demonstrated that pre-treatment of donors with CSF1-Fc increased the number and reconstitution potential of HSPC in blood following a HSC mobilising regimen of G-CSF treatment. These results indicate that CSF1-Fc conditioning could represent a therapeutic strategy to overcome poor HSC mobilisation and subsequently improve HSC transplantation outcomes.
Publisher: American Society of Hematology
Date: 09-1995
DOI: 10.1182/BLOOD.V86.5.1729.BLOODJOURNAL8651729
Abstract: We have previously shown that early human CD34high hematopoietic progenitors are maintained quiescent in part through autocrine transforming growth factor-beta 1 (TGF-beta 1). We also demonstrated that, in the presence of interleukin-3, interleukin-6, granulocyte colony-stimulating factor, and erythropoietin, TGF-beta 1 antisense oligonucleotides or anti-TGF-beta serum have an additive effect with KIT ligand (Steel factor [SF]), which suggests that they control different pathways of regulation in these conditions. This finding also suggests that autocrine TGF-beta 1 might suppress c-kit expression in primitive human hematopoietic progenitors. We have now distinguished two subpopulations of CD34high cells. One subpopulation expresses a c- kit mRNA that can be downmodulated by exogenous TGF-beta 1 within 6 hours. Another subpopulation of early CD34high cells expresses a low or undetectable level of c-kit mRNA, but its expression can be upmodulated within 6 hours by anti-TGF-beta. These effects disappear 48 hours after induction and cannot be maintained longer than 72 hours, even if TGF- beta 1 or anti-TGF-beta serum are added every day. Similar kinetics, although delayed, are observed with KIT protein expression. On the contrary, no specific effect of TGF-beta 1 was observed on c-fms, GAPDH, and transferrin receptor gene expression in these early progenitors. These results clarify the complex interaction between TGF- beta 1 and SF in normal early hematopoietic progenitors. SF does not switch off the TGF-beta 1 inhibitory pathway. Autocrine TGF-beta 1 appears to maintain these cells in a quiescent state, suppressing cell ision by downmodulating the receptor of SF, a key cytokine costimulator of early progenitors.
Publisher: American Society of Hematology
Date: 10-1998
DOI: 10.1182/BLOOD.V92.7.2461.2461_2461_2470
Abstract: The interaction between p145c-KIT and p210bcr-abl in transduced cell lines, and the selective outgrowth of normal progenitors during long-term culture of chronic myeloid leukemia (CML) cells on stroma deficient in stem-cell factor (SCF) suggests that the response of CML cells to SCF may be abnormal. We examined the proliferative effect of SCF(100 ng/mL), provided as the sole stimulus, on in idual CD34+ cells from five normal donors and five chronic-phase CML patients. Forty-eight percent of isolated single CML CD34+ cells proliferated after 6 days of culture to a mean of 18 cells, whereas only 8% of normal CD34+ cells proliferated (mean number of cells generated was 4). SCF, as a single agent, supported the survival and expansion of colony-forming unit–granulocyte-macrophage (CFU-GM) from CML CD34+CD38+ cells and the more primitive CML CD34+CD38− cells. These CFU-GM colonies were all bcr-abl positive, showing the specificity of SCF stimulation for the leukemic cell population. Coculture of CML and normal CD34+ cells showed exclusive growth of Ph+cells, suggesting that growth in SCF alone is not dependent on secretion of cytokines by CML cells. SCF augmentation of β1-integrin–mediated adhesion of CML CD34+cells to fibronectin was not increased when compared with the effect on normal CD34+ cells, suggesting that the proliferative and adhesive responses resulting from SCF stimulation are uncoupled. The increased proliferation may contribute to the accumulation of leukemic progenitors, which is a feature of CML.
Publisher: Public Library of Science (PLoS)
Date: 30-08-2017
Publisher: Humana Press
Date: 2012
DOI: 10.1007/978-1-61779-943-3_11
Abstract: An important factor contributing to hematopoietic stem cell (HSC) mobilization is the ability of mobilizing cytokines and chemotherapy to disturb the cellular components of HSC niches, particularly osteoblasts and their progenitors, and to inhibit the production of HSC supportive cytokines and chemokines. Although the mechanisms by which niche cells are inhibited by mobilizing treatments is still incompletely understood, it has recently emerged that bone marrow macrophages play a critical role in maintaining osteoblasts, bone formation, and the expression of CXCL12, KIT ligand, and angiopoietin-1 necessary to HSC maintenance. In this chapter, we describe how to mobilize HSC into the blood in mice by depleting macrophages with clodronate-loaded liposomes and compare this mode of mobilization to mobilization induced by granulocyte colony-stimulating factor and cyclophosphamide. Detailed methods to analyze mobilization of phenotypic and functional reconstituting HSC are described with ex les.
Publisher: The American Association of Immunologists
Date: 15-07-2000
DOI: 10.4049/JIMMUNOL.165.2.840
Abstract: The novel sialomucin, CD164, functions as both an adhesion receptor on human CD34+ cell subsets in bone marrow and as a potent negative regulator of CD34+ hemopoietic progenitor cell proliferation. These erse effects are mediated by at least two functional epitopes defined by the mAbs, 103B2/9E10 and 105A5. We report here the precise epitope mapping of these mAbs together with that of two other CD164 mAbs, N6B6 and 67D2. Using newly defined CD164 splice variants and a set of soluble recombinant chimeric proteins encoded by exons 1–6 of the CD164 gene, we demonstrate that the 105A5 and 103B2/9E10 functional epitopes map to distinct glycosylated regions within the first mucin domain of CD164. The N6B6 and 67D2 mAbs, in contrast, recognize closely associated and complex epitopes that rely on the conformational integrity of the CD164 molecule and encompass the cysteine-rich regions encoded by exons 2 and 3. On the basis of their sensitivities to reducing agents and to sialidase, O-sialoglycoprotease, and N-glycanase treatments, we have characterized CD164 epitopes and grouped them into three classes by analogy with CD34 epitope classification. The class I 105A5 epitope is sialidase, O-glycosidase, and O-sialoglycoprotease sensitive the class II 103B2/9E10 epitope is N-glycanase, O-glycosidase, and O-sialoglycoprotease sensitive and the class III N6B6 and 67D2 epitopes are not removed by such enzyme treatments. Collectively, this study indicates that the previously observed differential expression of CD164 epitopes in adult tissues is linked with cell type specific post-translational modifications and suggests a role for epitope-associated carbohydrate structures in CD164 function.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2008
Publisher: Elsevier BV
Date: 08-2021
DOI: 10.1016/J.EXPHEM.2021.07.001
Abstract: The bone marrow (BM) contains a mosaic of niches specialized in supporting different maturity stages of hematopoietic stem and progenitor cells such as hematopoietic stem cells and myeloid, lymphoid, and erythroid progenitors. Recent advances in BM imaging and conditional gene knockout mice have revealed that niches are a complex network of cells of mesenchymal, endothelial, neuronal, and hematopoietic origins, together with local physicochemical parameters. Within these complex structures, phagocytes, such as neutrophils, macrophages, and dendritic cells, all of which are of hematopoietic origin, have been found to be important in regulating several niches in the BM, including hematopoietic stem cell niches, erythropoietic niches, and niches involved in endosteal bone formation. There is also increasing evidence that these macrophages have an important role in adapting hematopoiesis, erythropoiesis, and bone formation in response to inflammatory stressors and play a key part in maintaining the integrity and function of these. Likewise, there is also accumulating evidence that subsets of monocytes, macrophages, and other phagocytes contribute to the progression and response to treatment of several lymphoid malignancies such as multiple myeloma, Hodgkin lymphoma, and non-Hodgkin lymphoma, as well as lymphoblastic leukemia, and may also play a role in myelodysplastic syndrome and myeloproliferative neoplasms associated with Noonan syndrome and aplastic anemia. In this review, the potential functions of macrophages and other phagocytes in normal and pathologic niches are discussed, as are the challenges in studying BM and other tissue-resident macrophages at the molecular level.
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.EXPHEM.2016.01.001
Abstract: Harvest of granulocyte colony-stimulating factor (G-CSF)-mobilized hematopoietic stem cells (HSCs) begins at day 5 of G-CSF administration, when most donors have achieved maximal mobilization. This is based on surrogate markers for HSC mobilization, such as CD34(+) cells and colony-forming activity in blood. However, CD34(+) cells or colony-forming units in culture (CFU-C) are heterogeneous cell populations with hugely ergent long-term repopulation potential on transplantation. HSC behavior is influenced by the vascular bed in the vicinity of which they reside. We hypothesized that G-CSF may mobilize sequentially cells proximal and more distal to bone marrow venous sinuses where HSCs enter the blood. We addressed this question with functional serial transplantation assays using blood and bone marrow after specific time points of G-CSF treatment in mice. We found that in mice, blood collected after only 48 hours of G-CSF administration was as enriched in serially reconstituting HSCs as blood collected at 5 days of G-CSF treatment. Similarly, mobilized Lin(-)CD34(+) cells were relatively enriched in more primitive Lin(-)CD34(+)CD38(-) cells at day 2 of G-CSF treatment compared with later points in half of human donors tested (n = 6). This suggests that in both humans and mice, hematopoietic progenitor and stem cells do not mobilize uniformly according to their maturation stage, with most potent HSCs mobilizing as early as day 2 of G-CSF.
Publisher: Informa UK Limited
Date: 12-2009
DOI: 10.1586/EHM.09.61
Abstract: The International Society of Experimental Hematology holds its annual meeting every northern summer. This year the meeting comprised of eight plenary sessions with distinguished invited speakers on in vivo imaging and tracking of hematopoietic stem cells (HSCs), HSC niches, epigenetic regulations of stem cells and regulation of stem cell fate, leukemogenesis, and mesenchymal stem cells. The small size of the meeting (300 attendees) permitted excellent discussion and face-to-face contacts between students, junior scientists and experts. Owing to the large number of keynote speakers, this report focuses on the most novel, unpublished data presented during the meeting.
Publisher: Oxford University Press (OUP)
Date: 21-05-2015
DOI: 10.1002/STEM.1978
Abstract: Despite positive testing in animal studies, more than 80% of novel drug candidates fail to proof their efficacy when tested in humans. This is primarily due to the use of preclinical models that are not able to recapitulate the physiological or pathological processes in humans. Hence, one of the key challenges in the field of translational medicine is to “make the model organism mouse more human.” To get answers to questions that would be prognostic of outcomes in human medicine, the mouse's genome can be altered in order to create a more permissive host that allows the engraftment of human cell systems. It has been shown in the past that these strategies can improve our understanding of tumor immunology. However, the translational benefits of these platforms have still to be proven. In the 21st century, several research groups and consortia around the world take up the challenge to improve our understanding of how to humanize the animal's genetic code, its cells and, based on tissue engineering principles, its extracellular microenvironment, its tissues, or entire organs with the ultimate goal to foster the translation of new therapeutic strategies from bench to bedside. This article provides an overview of the state of the art of humanized models of tumor immunology and highlights future developments in the field such as the application of tissue engineering and regenerative medicine strategies to further enhance humanized murine model systems. Stem Cells 2015 :1696–1704
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2007
Publisher: Ferrata Storti Foundation (Haematologica)
Date: 09-05-2019
Publisher: American Society of Hematology
Date: 11-1998
DOI: 10.1182/BLOOD.V92.9.3465.421K35_3465_3473
Abstract: The cellular and molecular mechanisms responsible for hematopoietic progenitor cell (HPC) mobilization from bone marrow (BM) into peripheral blood after administration of cytokines such as granulocyte colony-stimulating factor (G-CSF) are still unknown. In this study we show that high concentrations of soluble calcium induce the detachment of BM CD34+ HPC adherent on fibronectin, a major component of BM extracellular matrix. Because G-CSF has been shown to induce osteoporosis in patients with congenital neutropenia and in G-CSF–overexpressing transgenic mice, we hypothesized that short-term G-CSF administration may be sufficient to induce bone resorption, resulting in the release of soluble calcium in the endosteum leading in turn to the inhibition of attachment to fibronectin and the egress of HPC from the BM. We show herein that in humans, serum osteocalcin concentration, a specific marker of bone formation, is strongly reduced after 3 days of G-CSF administration. Furthermore, in patients mobilized with G-CSF either alone or in association with stem cell factor or interleukin-3, the reduction of serum osteocalcin is significantly correlated with the number of HPC mobilized in peripheral blood. Urine levels of deoxypyridinoline (DPyr), a specific marker of bone resorption, gradually elevated during the time course of G-CSF administration until day 7 after cessation of G-CSF, showing a simultaneous stimulation of bone degradation during G-CSF–induced HPC mobilization. In an in vivo murine model, we found that the number of osteoclasts was dramatically increased paralleling the elevation of DPyr after G-CSF administration. When pamidronate, an inhibitor of osteoclast-mediated bone resorption, was administered together with G-CSF in mice, the G-CSF–induced increase of DPyr levels was completely abolished whereas the numbers of colony-forming cells mobilized in peripheral blood were not decreased, but unexpectedly increased relative to the numbers elicited by G-CSF alone. Collectively, our data therefore show that short-term administration of G-CSF induces bone degradation by a simultaneous inhibition of bone formation and an enhanced osteoclast-mediated bone resorption. This increased bone resorption is inhibited by pamidronate without reducing G-CSF–induced HPC mobilization, suggesting that the activation of bone resorption after G-CSF administration is not the direct cause of HPC mobilization as initially hypothesized, but a parallel event. © 1998 by The American Society of Hematology.
Publisher: Oxford University Press (OUP)
Date: 26-12-2014
Abstract: Hypoxia-inducible factors (HIFs) are oxygen-sensitive transcription factors regulated by oxygen-dependent prolyl hydroxylase domain (PHD) enzymes and are key to cell adaptation to low oxygen. The hematopoietic stem cell (HSC) niche in the bone marrow is highly heterogeneous in terms of microvasculature and thus oxygen concentration. The importance of hypoxia and HIFs in the hematopoietic environment is becoming increasingly recognized. Many small compounds that inhibit PHDs have been developed, enabling HIFs to be pharmacologically stabilized in an oxygen-independent manner. The use of PHD inhibitors for therapeutic intervention in hematopoiesis is being increasingly investigated. PHD inhibitors are well established to increase erythropoietin production to correct anemia in hemodialysis patients. Pharmacological stabilization of HIF-1α protein with PHD inhibitors is also emerging as an important regulator of HSC proliferation and self-renewal. Administration of PHD inhibitors increases quiescence and decreases proliferation of HSCs in the bone marrow in vivo, thereby protecting them from high doses of irradiation and accelerating hematological recovery. Recent findings also show that stabilization of HIF-1α increases mobilization of HSCs in response to granulocyte colony-stimulating factor and plerixafor, suggesting that PHD inhibitors could be useful agents to increase mobilization success in patients requiring transplantation. These findings highlight the importance of the hypoxia-sensing pathway and HIFs in clinical hematology
Publisher: Springer Science and Business Media LLC
Date: 12-09-2013
DOI: 10.1038/LEU.2013.266
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.EXPHEM.2017.05.004
Abstract: Granulocyte colony-stimulating factor (G-CSF) is used routinely in the clinical setting to mobilize hematopoietic stem progenitor cells (HSPCs) into the patient's blood for collection and subsequent transplantation. However, a significant proportion of patients who have previously received chemotherapy or radiotherapy and require autologous HSPC transplantation cannot mobilize the minimal threshold of mobilized HSPCs to achieve rapid and successful hematopoietic reconstitution. Although several alternatives to the G-CSF regime have been tested, few are used in the clinical setting. We have shown previously in mice that administration of prolyl 4-hydroxylase domain enzyme (PHD) inhibitors, which stabilize hypoxia-inducible factor (HIF)-1α, synergize with G-CSF in vivo to enhance mouse HSPC mobilization into blood, leading to enhanced engraftment via an HSPC-intrinsic mechanism. To evaluate whether PHD inhibitors could be used to enhance mobilization of human HSPCs, we humanized nonobese, diabetic severe combined immune-deficient Il2rg
Publisher: Mary Ann Liebert Inc
Date: 18-06-2021
Publisher: American Society of Hematology
Date: 07-02-2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2011
Publisher: Elsevier BV
Date: 08-1991
Publisher: Cold Spring Harbor Laboratory
Date: 28-04-2021
DOI: 10.1101/2021.04.28.441876
Abstract: Mouse hematopoietic tissues contain abundant and heterogeneous populations of tissue-resident macrophages attributed trophic functions in control of immunity, hematopoiesis and bone homeostasis. A systematic strategy to characterise macrophage subsets in mouse bone marrow (BM), spleen and lymph node, unexpectedly revealed macrophage surface marker staining typically emanated from membrane-bound subcellular remnants associated with unrelated cell types. Remnant-restricted macrophage-specific membrane markers, cytoplasmic fluorescent reporters and mRNA were all detected in non-macrophage cell populations including isolated stem and progenitor cells. The profile of macrophage remnant association reflects adhesive interactions between macrophages and other cell types in vivo. Applying this knowledge, reduced macrophage remnant attachment to BM granulocytes in Siglec1 deficient mice was associated with compromised emergency granulocytosis, revealing a function for Siglec1 -dependent granulocyte-macrophage interactions. Analysis of published RNA-seq data for purified macrophage and non-macrophage populations indicates that macrophage fragmentation is a general phenomenon that confounds bulk and single cell analysis of disaggregated tissues.
Publisher: Elsevier BV
Date: 08-1997
DOI: 10.1016/S0022-1759(97)00109-9
Abstract: We report a simple procedure for the rapid development of an ELISA with the potential for wide application to any defined protein antigen. The procedure involves the expression of protein encoded by a PCR product, using a commercially available T-vector that adds a biotin tag, and a single step purification by affinity for streptavidin for direct use in ELISA. In our experiments, a recombinant protein from the nucleocapsid domain of the feline foamy virus gag gene was expressed as a fusion protein with a biotin tag and then applied directly to streptavidin-coated ELISA wells. An extract from a clone with the insert in antisense orientation was used as a control. Non-specific reactions with antigen extracts from both sense and antisense clones were observed in 6 of the 376 (1.6%) sera tested. Antibody to feline foamy virus, which forms a stable persistent infection in cats, was detected in 107 of 201 (53%) Australian cats, but none of 175 sera from veterinarians. There was a 100% correlation between FeFV antibody detected by ELISA, immunoblot, serum neutralisation and virus isolation, confirming that this test is sensitive and specific.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2015
Publisher: Springer Science and Business Media LLC
Date: 23-09-2010
DOI: 10.1038/LEU.2010.214
Abstract: The concept of hematopoietic stem cell (HSC) niche was formulated in 1978, but HSC niches remained unidentified for the following two decades largely owing to technical limitations. Sophisticated live microscopy techniques and genetic manipulations have identified the endosteal region of the bone marrow (BM) as a preferential site of residence for the most potent HSC - able to reconstitute in serial transplants - with osteoblasts and their progenitors as critical cellular elements of these endosteal niches. This article reviews the path to the discovery of these endosteal niches (often called 'osteoblastic' niches) for HSC, what cell types contribute to these niches with their known physical and biochemical features. In the past decade, a first wave of research uncovered many mechanisms responsible for HSC homing to, and mobilization from, the whole BM tissue. However, the recent discovery of endosteal HSC niches has initiated a second wave of research focusing on the mechanisms by which most primitive HSC lodge into and migrate out of their endosteal niches. The second part of this article reviews the current knowledge of the mechanisms of HSC lodgment into, retention in and mobilization from osteoblastic niches.
Publisher: Elsevier BV
Date: 02-1985
DOI: 10.1016/0014-4827(85)90563-4
Abstract: A gradient has been developed for separating free ligand from ligand bound to cells growing in suspension. This method can be used with all kinds of ligand but it is particularly useful for those ligands having the tiresome tendency to adhere to the cells non-specifically or to polymerize by themselves. This is the case of fibronectin, fibrinogen, immunoglobulins and many other plasma proteins. The gradient consists of two layers: an upper aqueous phase and a lower hydrophobic organic phase. The aqueous phase, a sucrose buffer, allows the cells to become well dispersed before they enter the hydrophobic phase which excludes the free ligand efficiently. This reduces non-specific binding and allows the accurate measurement of specific binding which could not be obtained with a gradient made of a single phase. Depending upon the size and the density of the cells, and the nature of the ligand, the assay method can be modified by changing the density or the nature of the hydrophilic and hydrophobic phases.
Publisher: American Society of Hematology
Date: 22-07-2010
DOI: 10.1182/BLOOD-2009-07-233437
Abstract: Hematopoietic stem cell (HSC) niches have been reported at the endosteum or adjacent to bone marrow (BM) vasculature. To investigate functional attributes of these niches, mice were perfused with Hoechst 33342 (Ho) in vivo before BM cell collection in presence of pump inhibitors and antibody stained. We report that the position of phenotypic HSCs, multipotent and myeloid progenitors relative to blood flow, follows a hierarchy reflecting differentiation stage, whereas mesenchymal stromal cells are perivascular. Furthermore, during granulocyte colony-stimulating factor–induced mobilization, HSCs migrated closer to blood flow, whereas stromal cells did not. Interestingly, phenotypic Lin−Sca1+KIT+CD41−CD48−CD150+ HSCs segregated into 2 groups (Honeg or Homed), based on degree of blood/Ho perfusion of their niche. HSCs capable of serial transplantation and long-term bromodeoxyuridine label retention were enriched in Honeg HSCs, whereas Homed HSCs cycled more frequently and only reconstituted a single host. This suggests that the most potent HSC niches are enriched in locally secreted factors and low oxygen tension due to negligible blood flow. Importantly, blood perfusion of niches correlates better with HSC function than absolute distance from vasculature. This technique enables prospective isolation of serially reconstituting HSCs distinct from other less potent HSCs of the same phenotype, based on the in vivo niche in which they reside.
Publisher: Springer Science and Business Media LLC
Date: 10-12-2016
DOI: 10.1007/S12185-016-2162-4
Abstract: Hematopoietic stem cells (HSC) reside in perivascular regions of the bone marrow (BM) embedded within a complex regulatory unit called the niche. Cellular components of HSC niches include vascular endothelial cells, mesenchymal stromal progenitor cells and a variety of mature hematopoietic cells such as macrophages, neutrophils, and megakaryocytes-further regulated by sympathetic nerves and complement components as described in this review. Three decades ago the discovery that cytokines induce a large number of HSC to mobilize from the BM into the blood where they are easily harvested, revolutionised the field of HSC transplantation-curative for immune-deficiencies and some malignancies. However, despite now routine use of granulocyte-colony stimulating factor (G-CSF) to mobilise HSC for transplant, only in last 15 years has research on the mechanisms behind why and how HSC can be induced to move into the blood began. These studies have revealed the complexity of the niche that retains HSC in the BM. This review describes how BM niches and HSC themselves change during administration of G-CSF-or in the recovery phase of chemotherapy-to facilitate movement of HSC into the blood, and research now leading to development of novel therapeutics to further boost HSC mobilization and transplant success.
Publisher: Informa UK Limited
Date: 1998
DOI: 10.3109/15419069809010781
Abstract: Beta-1 integrins have essential functions in hemopoietic and immune systems by controlling phenomenons such as cell homing and cell activation. The function alpha 4 beta 1 and alpha 5 beta 1 integrins is regulated by alent cations and, as demonstrated more recently, by mitogenic cytokines which activate them by "inside-out" mechanisms. Using the adhesive interaction of a cytokine-dependent human hemopoietic cell line to immobilized fibronectin, we have analyzed the requirements in alent cations Mn2+, Mg2+ and Ca2+ for alpha 4 beta 1 and alpha 5 beta 1 activation by "inside-out" mechanisms triggered by cytokines such as granulocyte-macrophage colony stimulating factor or KIT ligand, or by external conformational constraints with the function-activating anti-beta 1 integrin monoclonal antibody 8A2. The intrinsic difference between these two modes of beta 1 integrin activation was revealed by their different requirements in alent cations. We found that in the absence of any alent cations, alpha 4 beta 1 and alpha 5 beta 1 were non-functional even after further stimulation by cytokines or 8A2. However, whilst either Ca2+, Mg2+ or Mn2+ were able to restore adhesive functions of alpha 4 beta 1 and alpha 5 beta 1 when activated by 8A2, only Mg2+ and Mn2+ were able to support activation of alpha 4 beta 1 and alpha 5 beta 1 by cytokines. Furthermore, high concentrations of Ca2+ exceeding 20 mM dramatically inhibited cell adhesion to fibronectin induced by Mn2+ and cytokines but not by 8A2. On the contrary, in the presence of both Ca2+ and Mg2+, Mn2+ had an additive effect on the activation of alpha 4 beta 1 and alpha 5 beta 1 by mitogenic cytokines. The presence of the absence of these alent cations did not inhibit early tyrosine phosphorylation induced by the binding of KIT ligand to its tyrosine-kinase receptor KIT. Therefore, we propose that in hemopoietic cells, Ca2+, Mg2+ and Mn2+ may modulate in vivo alpha 4 beta 1 and alpha 5 beta 1 regulation by mitogenic cytokines, a phenomenon involved in the regulation of hemopoietic progenitor cell homing within the bone marrow.
Publisher: American Society of Hematology
Date: 15-03-1997
Abstract: Adhesive interactions between CD34+ hematopoietic progenitor cells (HPC) and bone marrow stroma are crucial for normal hematopoiesis, yet their molecular bases are still poorly elucidated. We have investigated whether cell surface proteoglycan CD44 can mediate adhesion of human CD34+ HPC to immobilized hyaluronan (HA), an abundant glycosaminoglycan of the bone marrow extracellular matrix. Our data show that, although CD34+ cells strongly express CD44, only 13.3% ± 1.1% spontaneously adheres to HA. Short-term methylcellulose assay showed that HA-adherent CD34+ cells comprised granulo-monocytic and erythroid committed progenitors (19.6% ± 2.5% and 7.3% ± 1.0% of the input, respectively). More primitive progenitors, such as pre–colony-forming units, also adhered to HA. Moreover, we found that CD44-mediated adhesion of CD34+ cells to HA could be enhanced by phorbol 12-myristate 13-acetate (PMA), the function-activating anti-CD44 monoclonal antibody H90, and cytokines such as granulocyte-monocyte colony-stimulating factor, interleukin-3 (IL-3), and stem cell factor. Enhancement through PMA required several hours, was protein-synthesis–dependent, and was associated with an increase of CD44 cell surface expression, whereas stimulation of adhesion by H90 monoclonal antibody and cytokines was very rapid and without alteration of CD44 expression. H90-induced activation occurred at 4°C and lasted for at least 2 hours, whereas activation by cytokines required incubation at 37°C and was transient. These data, which show for the first time that CD34+ HPC can directly adhere to HA via CD44, point out that this adhesive interaction to HA is a process that may also be physiologically regulated by cytokines.
Publisher: Elsevier BV
Date: 02-1990
DOI: 10.1016/0014-4827(90)90304-S
Abstract: Normal human hemopoietic cells such as early bone marrow progenitors, or lymphoma-derived cell lines such as Raji or JM cells, possess a low-affinity receptor specific for fibrinogen. This receptor triggers a mitogenic effect. It differs from the glycoprotein IIb-IIIa which is involved in fibrinogen-induced platelet aggregation. We demonstrate here that this mitogenic fibrinogen receptor (MFR) can be internalized or reexpressed, depending on culture conditions. Internalization was temperature-dependent. At 37 degrees C in the presence of cycloheximide or actinomycin D, the half-life of cell surface MFRs was 2 h, independent of receptor occupancy. Binding of fibrinogen to the MFR resulted in a down-regulation which was fibrinogen dose-dependent. This occurred in serum-supplemented medium but not in defined medium supplemented with fatty acids. Reexpression of MFRs could be induced in 28 to 42 h by serum removal. The down-regulation of mitogenic receptors in plasma or serum could explain why normal cells do not proliferate in the peripheral blood.
Publisher: Mary Ann Liebert Inc
Date: 10-2008
Abstract: We compared potential trafficking mechanisms used by human (h) multipotent mesenchymal stem cells (MSC) derived from bone marrow (bm) or placenta (p). Both hbmMSC and hpMSC expressed a broad range of cell surface adhesion molecules including beta1-integrins (CD29) and CD44. Array data showed that both hbmMSC and hpMSC expressed mRNA for the cell adhesion molecules CD54 (ICAM-1), E-cadherin, CD166 (ALCAM), CD56 (NCAM), CD106 (VCAM-1), CD49a, b, c, e and f (integrins alpha1, 2, 3, 4 and 6), integrin alpha11, CD51 (integrin alphaV), and CD29 (integrins beta1). Functional binding of hpMSC, but not hbmMSC to VCAM-1 was demonstrated using recombinant chimeric constructs. Neither bone marrow nor placental MSC expressed ligands to endothelial selectins such as PSGL-1 or sialyl Lewis X (sLe(x)) carbohydrates and neither were able to bind functionally to chimeric constructs of the endothelial selectins CD62E (E-selectin) and CD62P (P-selectin). Furthermore, MSC expressed a restricted range of transferases necessary for expression of sLe(x), with no detectable expression of fucosyl transferases IV or VII. Placental MSC, but not hbmMSC, expressed mRNA for the chemokine receptors CCR1 and CCR3, and both hbmMSC and hpMSC expressed mRNA for CCR7, CCR8, CCR10, CCR11, CXCR4 and CXCR6. Intracellular chemokine receptor protein expression of CCR1, CCR3, CXCR3, CXCR4 and CXCR6 was detected in both hbmMSC and hpMSC. Cell surface expression of chemokine receptors was much more restricted with only CXCR6 displaying a strong signal on hbmMSC and hpMSC. Although cell surface expression of CXCR4 was not detected, MSC migrated in response to its ligand, CXCL12 (SDF-1). Thus, hbmMSC and hpMSC have an almost identical profile for cell surface adhesion and chemokine receptor molecules at the mRNA and protein levels. However, at the functional level, hpMSC likely utilise VLA-4-mediated binding in a superior manner to hbmMSC and thus may have superior engraftment properties to hbmMSC in vivo.
Publisher: Springer Science and Business Media LLC
Date: 27-04-2020
DOI: 10.1038/S41467-020-15817-5
Abstract: The endothelial cell adhesion molecule E-selectin is a key component of the bone marrow hematopoietic stem cell (HSC) vascular niche regulating balance between HSC self-renewal and commitment. We now report in contrast, E-selectin directly triggers signaling pathways that promote malignant cell survival and regeneration. Using acute myeloid leukemia (AML) mouse models, we show AML blasts release inflammatory mediators that upregulate endothelial niche E-selectin expression. Alterations in cell-surface glycosylation associated with oncogenesis enhances AML blast binding to E-selectin and enable promotion of pro-survival signaling through AKT/NF-κB pathways. In vivo AML blasts with highest E-selectin binding potential are 12-fold more likely to survive chemotherapy and main contributors to disease relapse. Absence (in Sele −/− hosts) or therapeutic blockade of E-selectin using small molecule mimetic GMI-1271/Uproleselan effectively inhibits this niche-mediated pro-survival signaling, d ens AML blast regeneration, and strongly synergizes with chemotherapy, doubling the duration of mouse survival over chemotherapy alone, whilst protecting endogenous HSC.
Publisher: Proceedings of the National Academy of Sciences
Date: 15-09-1993
Abstract: Using optimal culture conditions in which the transforming growth factor beta 1 (TGF-beta 1) inhibitory loop has been interrupted by antisense TGF-beta 1 oligonucleotides or anti-TGF-beta serum, we have compared the proliferative capacities and the abilities of the CD34+ CD38- cell populations from bone marrow and umbilical cord blood to generate early progenitors in long-term cultures. The CD34+ CD38- fraction of umbilical cord blood accounts for 4% of the CD34+ fraction compared to only 1% in bone marrow, indicating that umbilical cord blood may be relatively enriched in stem cells. We estimate that the CD34+ CD38- cells from a typical umbilical cord blood s le produce equivalent numbers of colony-forming units (CFU)-granulocyte/erythrocyte/macrophage/megakaryocyte, twice as many CFU-granulocyte/macrophage (GM) and 3 times as many burst-forming units-erythroid as the same population from an average bone marrow s le used in adult transplantation. In addition, the colonies resulting from the umbilical cord blood s les were significantly larger than those from bone marrow, indicating a greater growth potential. However, the content of later progenitors, which may be important for short-term reconstitution, was less in umbilical cord blood-derived than in bone marrow-derived cell preparations, as estimated by a 4-fold lower production of CFU-GM in long-term cultures of CD34+ CD38+ cells. This deficit is partially compensated by the higher growth capacity of the resulting CFU-GM. These studies suggest that umbilical cord blood is a suitable source of cells for adult transplantation.
Publisher: American Society of Hematology
Date: 03-2004
DOI: 10.1182/BLOOD-2003-06-1921
Abstract: Although both P- and E-selectin are constitutively expressed on bone marrow endothelial cells, their role in the regulation of hematopoiesis has only recently been investigated. We have previously shown that P-selectin glycoprotein ligand-l (PSGL-1/CD162) is expressed by primitive human bone marrow CD34+ cells, mediates their adhesion to P-selectin, and, more importantly, inhibits their proliferation. We now demonstrate that adhesion to E-selectin inhibits the proliferation of human CD34+ cells isolated either from human umbilical cord blood, adult mobilized blood, or steady-state bone marrow. Furthermore, a subpopulation, which does not contain the most primitive hematopoietic progenitor cells, undergoes apoptosis following E-selectin–mediated adhesion. The same phenomenon was observed in cells isolated from mouse bone marrow. Using lineage-negative Sca-1+ c-KIT+ bone marrow cells from PSGL-1–/– and wild-type mice, we establish that PSGL-1 is not the ligand involved in E-selectin–mediated growth inhibition and apoptosis. Moreover, stable transfection of the human myeloid cell line K562 (which does not express PSGL-1) with α(1,3) fucosyltransferase VII alone was sufficient to recapitulate the E-selectin–mediated growth inhibition and apoptosis observed in hematopoietic progenitor cells. These data demonstrate that an E-selectin ligand(s) other than PSGL-1 transduces growth inhibitory and proapoptotic signals and requires posttranslational fucosylation to be functional.
Publisher: Springer Science and Business Media LLC
Date: 21-10-2020
DOI: 10.1007/S11914-020-00636-W
Abstract: Neurogenic heterotopic ossification (NHO) is the abnormal formation of extra-skeletal bones in periarticular muscles after damage to the central nervous system (CNS) such as spinal cord injury (SCI), traumatic brain injury (TBI), stroke, or cerebral anoxia. The purpose of this review is to summarize recent developments in the understanding of NHO pathophysiology and pathogenesis. Recent animal models of NHO and recent findings investigating the communication between CNS injury, tissue inflammation, and upcoming NHO therapeutics are discussed. Animal models of NHO following TBI or SCI have shown that NHO requires the combined effects of a severe CNS injury and soft tissue damage, in particular muscular inflammation and the infiltration of macrophages into damaged muscles plays a key role. In the context of a CNS injury, the inflammatory response to soft tissue damage is exaggerated and persistent with excessive signaling via substance P-, oncostatin M-, and TGF-β1-mediated pathways. This review provides an overview of the known animal models and mechanisms of NHO and current therapeutic interventions for NHO patients. While some of the inflammatory mechanisms leading to NHO are common with other forms of traumatic and genetic heterotopic ossifications (HO), NHOs uniquely involve systemic changes in response to CNS injury. Future research into these CNS-mediated mechanisms is likely to reveal new targetable pathways to prevent NHO development in patients.
Publisher: American Society of Hematology
Date: 16-08-2018
DOI: 10.1182/BLOOD-2018-01-829663
Abstract: Recipient macrophages persist in hematopoietic tissues and self-repopulate via in situ proliferation after syngeneic transplantation. Targeted depletion of recipient CD169+ macrophages after transplant impaired long-term bone marrow engraftment of hematopoietic stem cells.
Publisher: American Society of Hematology
Date: 24-04-2014
DOI: 10.1182/BLOOD-2012-02-413187
Abstract: A mutation preventing interaction between c-Myb and p300 prevents transformation and leukemia induction by MLL-AF9 and AML1-ETO9a oncogenes. Identifying agents that block the c-Myb-p300 interaction may be a valuable approach to developing a therapy for acute myeloid leukemia.
Publisher: Elsevier BV
Date: 09-1997
DOI: 10.1016/S0950-3536(97)80022-4
Abstract: In the adult mammal, haemopoiesis is restricted to the extravascular compartment of the bone marrow (BM) where primitive haemopoietic stem cells (HSC) and their clonogenic progeny develop in intimate contiguity with a heterogeneous population of stromal cells that comprise the haemopoietic micro-environment (HM). Although the importance of cellular interactions between primitive haemopoietic progenitor cells (HPC) and marrow stromal cells is well established, precise definition of the nature of many of these interactions at the molecular level is lacking and remains an objective of fundamental importance to understanding of haemopoietic regulation. Current data suggest that a wide variety of cell surface molecules representing several adhesion molecule superfamilies, including integrins, selectins, sialomucins and the immunoglobulin gene superfamily, are involved in supporting cell-cell and cell-extracellular matrix (ECM) interactions. These erse CAM-ligand interactions, rather than simply serving to initiate and maintain contact between HPC and stromal cells and ECM components, also have an additional, more direct role in controlling the growth and development of primitive haemopoietic cells.
Publisher: Oxford University Press (OUP)
Date: 03-05-2007
DOI: 10.1634/STEMCELLS.2006-0688
Abstract: Despite the fact that many hypoxia-inducible genes are important in hematopoiesis, the spatial distribution of oxygen in the bone marrow (BM) has not previously been explored in vivo. Using the hypoxia bioprobe pimonidazole, we showed by confocal laser scanning microscopy that the endosteum at the bone-BM interface is hypoxic, with constitutive expression of hypoxia-inducible transcription factor-1α (HIF-1α) protein in steady-state mice. Interestingly, at the peak of hematopoietic stem and progenitor cell (HSPC) mobilization induced by either granulocyte colony-stimulating factor or cyclophosphamide, hypoxic areas expand through the central BM. Furthermore, we found that HSPC mobilization leads to increased levels of HIF-1α protein and increased expression of vascular endothelial growth factor A (VEGF-A) mRNA throughout the BM, with an accumulation of VEGF-A protein in BM endothelial sinuses. VEGF-A is a cytokine known to induce stem cell mobilization, vasodilatation, and vascular permeability in vivo. We therefore propose that the expansion in myeloid progenitors that occurs during mobilization depletes the BM hematopoietic microenvironment of O2, leading to local hypoxia, stabilization of HIF-1α transcription factor in BM cells, increased transcription of VEGF-A, and accumulation of VEGF-A protein on BM sinuses that increases vascular permeability. Disclosure of potential conflicts of interest is found at the end of this article.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2016
Publisher: Elsevier BV
Date: 02-2020
Publisher: Frontiers Media SA
Date: 06-10-2020
Publisher: Wiley
Date: 09-03-2021
DOI: 10.1111/IMCB.12447
Abstract: The endothelial adhesion protein E‐selectin/CD62E is not required for leukocyte homing, unlike closely related family member P‐selectin/CD62P. As transmigration through the endothelium is one of the first steps in generating a local immune response, we hypothesized that E‐selectin may play additional roles in the early stages of immune activation. We found contact with E‐selectin, but not P‐selectin or vascular cell adhesion molecule 1 (CD106), induced phosphorylation of protein kinase B (AKT) and nuclear factor‐κB in mouse bone marrow‐derived macrophages (BMDMs) in vitro . This occurred within 15 min of E‐selectin contact and was dependent on phosphatidylinositol‐3 kinase activity. Binding to E‐selectin activated downstream proteins including mammalian target of rapamycin, p70 ribosomal protein S6 kinase and eukaryotic translation initiation factor 4E‐binding protein 1. Functionally, adhesion to E‐selectin induced upregulation of CD86 expression and CCL2 secretion. We next asked whether contact with E‐selectin impacts further BMDM stimulation. We found enhanced secretion of both interleukin (IL)‐10 and CCL2, but not tumor necrosis factor or IL‐6 in response to lipopolysaccharide (LPS) stimulation after adhesion to E‐selectin. Importantly, adhesion to E‐selectin did not polarize BMDMs to one type of response but enhanced both arginase activity and nitric oxide production following IL‐4 or LPS stimulation, respectively. In cultured human monocytes, adhesion to E‐selectin similarly induced phosphorylation of AKT. Finally, when E‐selectin was blocked in vivo in mice, thioglycollate‐elicited macrophages showed reduced CD86 expression, validating our in vitro studies. Our results imply functions for E‐selectin beyond homing and suggest that E‐selectin plays an early role in priming and lifying innate immune responses.
Publisher: Informa UK Limited
Date: 1996
DOI: 10.3109/10428199609093438
Abstract: The CD44 cell surface molecule has been shown to be the principal cell surface receptor for hyaluronan (or hyaluronic acid), a glycosaminoglycan component of marrow extracellular matrix. However, its affinity for hyaluronan is not constitutive, since it depends on the cell type, the stage of differentiation and on activation by external stimuli including certain anti-CD44 antibodies and phorbol esters. Except for a few lymphoid cell lines, hematopoietic cells do not spontaneously bind hyaluronan and initial studies reported that, contrary to lymphocytes, myeloid cells could not be activated to bind hyaluronan. Because CD44 plays an important role in the initial phases of hematopoiesis, as shown by experiments using blocking anti-CD44 monoclonal antibodies, its capacity to mediate adhesion of primitive myeloid cells has been investigated. It was found that CD44 could mediate spontaneous adhesion to hyaluronan of immature myeloid cell lines KG1, KG1a, and TF1, which serve as a model for hematopoietic progenitors. However, despite expressing high amounts of CD44, no more than 15% of bone marrow progenitors could adhere to hyaluronan. Recent experiments have shown that a very important feature of CD44 is its capacity to be rapidly activated by certain antibodies and cytokines (GM-CSF and KL) from a low affinity to a high affinity state for hyaluronan. These data shed light on striking similarities in the functional regulation of CD44 and of the two integrin receptors VLA-4 (a4b1), and VLA-5 (a5b1), which are also expressed on hematopoietic progenitors. The relevance of these data to the regulation of normal hematopoiesis and mobilization of CD34+ progenitors in the view of cell grafting is analyzed. In addition, we show that in idiopathic myelofibrosis, the amount of hyaluronan is markedly increased in the extracellular matrix from the myeloproliferative spleen. Considering that the production of cytokines is enhanced in this disease, we discuss whether CD44-hyaluronan interaction may have a role in the pathophysiology of this myeloproliferative syndrome.
Publisher: Springer Science and Business Media LLC
Date: 25-02-2022
DOI: 10.1038/S41413-022-00188-Y
Abstract: The cells of origin of neurogenic heterotopic ossifications (NHOs), which develop frequently in the periarticular muscles following spinal cord injuries (SCIs) and traumatic brain injuries, remain unclear because skeletal muscle harbors two progenitor cell populations: satellite cells (SCs), which are myogenic, and fibroadipogenic progenitors (FAPs), which are mesenchymal. Lineage-tracing experiments using the Cre recombinase/LoxP system were performed in two mouse strains with the fluorescent protein ZsGreen specifically expressed in either SCs or FAPs in skeletal muscles under the control of the Pax7 or Prrx1 gene promoter, respectively. These experiments demonstrate that following muscle injury, SCI causes the upregulation of PDGFRα expression on FAPs but not SCs and the failure of SCs to regenerate myofibers in the injured muscle, with reduced apoptosis and continued proliferation of muscle resident FAPs enabling their osteogenic differentiation into NHOs. No cells expressing ZsGreen under the Prrx1 promoter were detected in the blood after injury, suggesting that the cells of origin of NHOs are locally derived from the injured muscle. We validated these findings using human NHO biopsies. PDGFRα + mesenchymal cells isolated from the muscle surrounding NHO biopsies could develop ectopic human bones when transplanted into immunocompromised mice, whereas CD56 + myogenic cells had a much lower potential. Therefore, NHO is a pathology of the injured muscle in which SCI reprograms FAPs to undergo uncontrolled proliferation and differentiation into osteoblasts.
Publisher: Rockefeller University Press
Date: 03-03-2021
DOI: 10.1084/JEM.20201452
Abstract: Vincristine is an important component of many regimens used for pediatric and adult malignancies, but it causes a dose-limiting sensorimotor neuropathy for which there is no effective treatment. This study aimed to delineate the neuro-inflammatory mechanisms contributing to the development of mechanical allodynia and gait disturbances in a murine model of vincristine-induced neuropathy, as well as to identify novel treatment approaches. Here, we show that vincristine-induced peripheral neuropathy is driven by activation of the NLRP3 inflammasome and subsequent release of interleukin-1β from macrophages, with mechanical allodynia and gait disturbances significantly reduced in knockout mice lacking NLRP3 signaling pathway components, or after treatment with the NLRP3 inhibitor MCC950. Moreover, treatment with the IL-1 receptor antagonist anakinra prevented the development of vincristine-induced neuropathy without adversely affecting chemotherapy efficacy or tumor progression in patient-derived medulloblastoma xenograph models. These results detail the neuro-inflammatory mechanisms leading to vincristine-induced peripheral neuropathy and suggest that repurposing anakinra may be an effective co-treatment strategy to prevent vincristine-induced peripheral neuropathy.
Publisher: Wiley
Date: 27-12-2018
DOI: 10.1002/JBMR.3346
Publisher: Springer US
Date: 2023
Publisher: American Society of Hematology
Date: 11-2005
DOI: 10.1182/BLOOD-2004-01-0272
Abstract: Accumulating evidence indicates that interaction of stromal cell-derived factor 1 (SDF-1/CXCL12 [CXC motif, ligand 12]) with its cognate receptor, CXCR4 (CXC motif, receptor 4), generates signals that regulate hematopoietic progenitor cell (HPC) trafficking in the bone marrow. During granulocyte colony-stimulating factor (G-CSF)–induced HPC mobilization, CXCL12 protein expression in the bone marrow decreases. Herein, we show that in a series of transgenic mice carrying targeted mutations of their G-CSF receptor and displaying markedly different G-CSF–induced HPC mobilization responses, the decrease in bone marrow CXCL12 protein expression closely correlates with the degree of HPC mobilization. G-CSF treatment induced a decrease in bone marrow CXCL12 mRNA that closely mirrored the fall in CXCL12 protein. Cell sorting experiments showed that osteoblasts and to a lesser degree endothelial cells are the major sources of CXCL12 production in the bone marrow. Interestingly, osteoblast activity, as measured by histomorphometry and osteocalcin expression, is strongly down-regulated during G-CSF treatment. However, the G-CSF receptor is not expressed on osteoblasts accordingly, G-CSF had no direct effect on osteoblast function. Collectively, these data suggest a model in which G-CSF, through an indirect mechanism, potently inhibits osteoblast activity resulting in decreased CXCL12 expression in the bone marrow. The consequent attenuation of CXCR4 signaling ultimately leads to HPC mobilization.
Publisher: Frontiers Media SA
Date: 07-03-2019
Publisher: Springer Science and Business Media LLC
Date: 14-05-2022
DOI: 10.1007/S11914-022-00729-8
Abstract: Inflammasomes are multimeric protein structures with crucial roles in host responses against infections and injuries. The importance of inflammasome activation goes beyond host defense as a dysregulated inflammasome and subsequent secretion of IL-1 family members is believed to be involved in the pathogenesis of various diseases, some of which also produce skeletal manifestations. The purpose of this review is to summarize recent developments in the understanding of inflammasome regulation and IL-1 family members in bone physiology and pathology and current therapeutics will be discussed. Small animal models have been vital to help understand how the inflammasome regulates bone dynamics. Animal models with gain or loss of function in various inflammasome components or IL-1 family signaling have illustrated how these systems can impact numerous bone pathologies and have been utilized to test new inflammasome therapeutics. It is increasingly clear that a tightly regulated inflammasome is required not only for host defense but for skeletal homeostasis, as a dysregulated inflammasome is linked to diseases of pathological bone accrual and loss. Given the complexities of inflammasome activation and redundancies in IL-1 activation and secretion, targeting these pathways is at times challenging. Ongoing research into inflammasome-mediated mechanisms will allow the development of new therapeutics for inflammasome/IL-1 diseases.
Publisher: American Society of Hematology
Date: 08-1993
DOI: 10.1182/BLOOD.V82.3.800.800
Abstract: The effect of human fibrinogen on the proliferation of purified SBA- CD34+ human bone marrow progenitors was investigated in clonal cultures. Fibrinogen alone or in combination with erythropoietin had no significant effect. However, in the presence of recombinant human interleukin-3 (IL-3), fibrinogen increased significantly in a dose- dependent manner the number of mixed and burst-forming unit-ethrocyte-- derived colonies, whereas the number of other colonies did not significantly change. In the presence of fibrinogen, low concentrations of IL-3 (0.17 U/mL) produced three times more mixed colonies than without fibrinogen, reaching the number of colonies obtained with optimal concentrations of IL-3 (1.67 U/mL). Fibrinogen fragment D had the same effect in the presence of IL-3 as intact fibrinogen, whereas fibrinogen fragment E and human collagen IV did not. This effect was not mediated by integrins, because peptides or monoclonal antibodies that block fibrinogen binding on integrins alpha IIb beta 3, alpha v beta 3 (RGD-peptides), alpha m beta 2 (OKM-1), and alpha x beta 2 (HC1/1) did not affect the observed mitogenic effect. The mitogenic effect of fibrinogen and its D fragment was not mediated by induction of IL-6 or granulocyte--colony-stimulating factor secretion, because it was not inhibited by blocking antisera against these two growth factors. Our results indicate that fibrinogen potentiates the effect of IL-3 on primitive hematopoietic progenitors and suggest that the mitogenic effect of fibrinogen could be mediated via a specific mitogenic receptor that does not belong to the integrin family.
Publisher: American Society of Hematology
Date: 27-10-2011
DOI: 10.1182/BLOOD-2011-06-318220
Abstract: Transplantation with 2-5 × 106 mobilized CD34+cells/kg body weight lowers transplantation costs and mortality. Mobilization is most commonly performed with recombinant human G-CSF with or without chemotherapy, but a proportion of patients/donors fail to mobilize sufficient cells. BM disease, prior treatment, and age are factors influencing mobilization, but genetics also contributes. Mobilization may fail because of the changes affecting the HSC rogenitor cell/BM niche integrity and chemotaxis. Poor mobilization affects patient outcome and increases resource use. Until recently increasing G-CSF dose and adding SCF have been used in poor mobilizers with limited success. However, plerixafor through its rapid direct blockage of the CXCR4/CXCL12 chemotaxis pathway and synergy with G-CSF and chemotherapy has become a new and important agent for mobilization. Its efficacy in upfront and failed mobilizers is well established. To maximize HSC harvest in poor mobilizers the clinician needs to optimize current mobilization protocols and to integrate novel agents such as plerixafor. These include when to mobilize in relation to chemotherapy, how to schedule and perform apheresis, how to identify poor mobilizers, and what are the criteria for preemptive and immediate salvage use of plerixafor.
Publisher: Elsevier BV
Date: 05-2019
Publisher: Springer Science and Business Media LLC
Date: 06-1992
DOI: 10.1007/BF02634052
Publisher: Wiley
Date: 06-2001
DOI: 10.1111/J.1749-6632.2001.TB03590.X
Abstract: Current data suggest that interplay between two classes of molecules contributes to the regulation of hematopoiesis: hematopoietic growth factors, which regulate the survival, proliferation, and development of primitive hematopoietic cells and cell adhesion molecules (CAMs), which are responsible for the localization of hematopoiesis to the bone marrow (BM) and for mediating physical association between developing hematopoietic cells and marrow stromal tissue. A range of cell surface molecules representing several CAM superfamilies including integrins, selectins, the immunoglobulin gene superfamily and an emerging family of mucin-like molecules (the sialomucins) are involved in supporting cell-cell and cell-extracellular matrix (ECM) interactions between primitive hematopoietic cells and the stromal cell-mediated hematopoietic microenvironment (HM) of the bone marrow. There is abundant evidence in non-hematopoietic tissues that CAMs are signalling molecules which participate in a range of signal transduction events important not only for regulating cell adhesion and motility, but also for cell growth and survival. Although the signalling functions of CAMs have not been studied extensively in primitive hematopoietic progenitors (HPCs), extrapolation from burgeoning data in other systems is consistent with the hypothesis that hematopoiesis within the BM is regulated by interaction between signals generated locally by CAMs and those elicited by cytokines. Evidence in support of this notion was initially provided by studies on normal HPCs demonstrating cross-talk between members of the integrin superfamily and cytokine receptors. In this article we review recent reports that mucin-like molecules are also signalling molecules on primitive hematopoietic cells and that the signals they deliver potently inhibit hematopoiesis.
Publisher: American Society for Clinical Investigation
Date: 02-11-2017
Publisher: Elsevier BV
Date: 09-1999
DOI: 10.1016/S1074-7613(00)80112-0
Abstract: Cellular interactions are critical for the regulation of hematopoiesis. The sialomucin PSGL-1/CD162 mediates the attachment of mature leukocytes to P-selectin. We now show that PSGL-1 also functions as the sole receptor for P-selectin on primitive human CD34+ hematopoietic progenitor cells (HPC). More importantly, ligation of PSGL-1 by immobilized or soluble ligand or anti-PSGL-1 antibody results in a profound suppression of HPC proliferation stimulated by potent combinations of early acting hematopoietic growth factors. These data demonstrate an unanticipated but extremely marked growth-inhibitory effect of P-selectin on hematopoiesis and provide direct evidence that PSGL-1, in addition to its well-documented role as an adhesion molecule on mature leukocytes, is a potent negative regulator of human hematopoietic progenitors.
Publisher: Rockefeller University Press
Date: 10-1991
Abstract: We have used antisense oligonucleotides to study the roles of transforming growth factor beta (TGF-beta) and the two antioncogenes, retinoblastoma susceptibility (Rb) and p53, in the negative regulation of proliferation of early hematopoietic cells in culture. The antisense TGF-beta sequence significantly enhanced the frequency of colony formation by multi-lineage, early erythroid, and granulomonocytic progenitors, but did not affect colony formation by late progenitors. Single cell culture and limiting dilution analysis indicated that autocrine TGF-beta is produced by a subpopulation of early progenitors. Antisense Rb but not antisense p53 yielded similar results in releasing multipotential progenitors (colony-forming unit-granulocyte/erythroid/macrophage/megakaryocyte) from quiescence. Rb antisense could partially reverse the inhibitory effect of exogenous TGF-beta. Anti-TGF-beta blocking antibodies, antisense TGF-beta, or Rb oligonucleotides all had similar effects. No additive effects were observed when these reagents were combined, suggesting a common pathway of action. Our results are consistent with the model that autocrine production of TGF-beta negatively regulates the cycling status of early hematopoietic progenitors through interaction with the Rb gene product.
Publisher: Elsevier BV
Date: 05-2002
DOI: 10.1016/S0301-472X(02)00788-9
Abstract: Hematopoietic stem and progenitor cells normally reside in the bone marrow but can be mobilized into the peripheral blood following treatment with granulocyte colony-stimulating factor (G-CSF) or myelosuppressive chemotherapy. Although the number of transplants performed with mobilized blood currently exceeds those performed with bone marrow, little is known of the molecular mechanisms responsible for this phenomenon. We sought to determine whether mobilization induced by G-CSF or chemotherapy was triggered by common or distinct mechanisms. Balb/c mice were mobilized with either G-CSF alone, cyclophosphamide alone, or the combination of both agents. Spleens, peripheral blood, bone marrow extracellular fluids, and cells were taken at different time points and analyzed for the expression of VCAM-1, the number of peripheral blood progenitor cells, concentration of neutrophil proteases, and number of granulocytes. Administration of either G-CSF or the myelosuppressive agent cyclophosphamide results in a sharp reduction of VCAM-1/CD106 expression in the bone marrow that coincides with the accumulation of granulocytic precursors and release of active neutrophil proteases neutrophil elastase and cathepsin G that directly cleave VCAM-1/CD106 in vitro. These events follow precisely the kinetics of hematopoietic progenitor cell mobilization into the peripheral blood. We have identified a commonality of events during mobilization induced by either G-CSF or chemotherapy, which include the accumulation in the bone marrow of active neutrophil proteases that directly cleave VCAM-1 and lead to the sharp reduction of VCAM-1 expression in this tissue.
Publisher: Wiley
Date: 27-04-2016
DOI: 10.1002/PATH.4718
Abstract: Skeletal metastases present a major clinical challenge for prostate cancer patient care, inflicting distinctive mixed osteoblastic and osteolytic lesions that cause morbidity and refractory skeletal complications. Macrophages are abundant in bone and bone marrow and can influence both osteoblast and osteoclast function in physiology and pathology. Herein, we examined the role of macrophages in prostate cancer bone lesions, particularly the osteoblastic response. First, macrophage and lymphocyte distributions were qualitatively assessed in patient's prostate cancer skeletal lesions by immunohistochemistry. Second, macrophage functional contributions to prostate tumour growth in bone were explored using an immune-competent mouse model combined with two independent approaches to achieve in vivo macrophage depletion: liposome encapsulated clodronate that depletes phagocytic cells (including macrophages and osteoclasts) and targeted depletion of CD169(+) macrophages using a suicide gene knock-in model. Immunohistochemistry and histomorphometric analysis were performed to quantitatively assess cancer-induced bone changes. In human bone metastasis specimens, CD68(+) macrophages were consistently located within the tumour mass. Osteal macrophages (osteomacs) were associated with pathological woven bone within the metastatic lesions. In contrast, lymphocytes were inconsistently present in prostate cancer skeletal lesions and when detected, had varied distributions. In the immune-competent mouse model, CD169(+) macrophage ablation significantly inhibited prostate cancer-induced woven bone formation, suggesting that CD169(+) macrophages within pathological woven bone are integral to tumour-induced bone formation. In contrast, pan-phagocytic cell, but not targeted CD169(+) macrophage depletion resulted in increased tumour mass, indicating that CD169(-) macrophage subset(s) and/or osteoclasts influenced tumour growth. In summary, these observations indicate a prominent role for macrophages in prostate cancer bone metastasis that may be therapeutically targetable to reduce the negative skeletal impacts of this malignancy, including tumour-induced bone modelling. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Publisher: Mary Ann Liebert Inc
Date: 02-2022
Publisher: Public Library of Science (PLoS)
Date: 30-09-2010
Publisher: Frontiers Media SA
Date: 24-07-2020
Publisher: Elsevier BV
Date: 08-2006
DOI: 10.1016/J.EXPHEM.2006.04.005
Abstract: Mobilization is now used worldwide to collect large numbers of hematopoietic stem and progenitor cells (HSPCs) for transplantation. Although the first mobilizing agents were discovered largely by accident, discovery of more efficient mobilizing agents will require a better understanding of the molecular mechanisms responsible. During the past 5 years, a number of mechanisms have been identified, shedding new light on the dynamics of the hematopoietic system in vivo and on the intricate relationship between hematopoiesis, innate immunity, and bone. After briefly reviewing the mechanisms by which circulating HSPCs home into the bone marrow and what keeps them there, the current knowledge of mechanisms responsible for HSPC mobilization in response to hematopoietic growth factors such as granulocyte colony-stimulating factor, chemotherapy, chemokines, and polyanions will be discussed together with current strategies developed to further increase HSPC mobilization.
Publisher: Elsevier BV
Date: 11-2021
DOI: 10.1016/J.EXPHEM.2021.08.011
Abstract: It has recently emerged that tissue-resident macrophages are key regulators of several stem cell niches orchestrating tissue formation during development, as well as postnatally, when they also organize the repair and regeneration of many tissues including the hemopoietic tissue. The fact that macrophages are also master regulators and effectors of innate immunity and inflammation allows them to coordinate hematopoietic response to infections, injuries, and inflammation. After recently reviewing the roles of phagocytes and macrophages in regulating normal and pathologic hematopoietic stem cell niches, we now focus on the key roles of macrophages in regulating erythropoiesis and iron homeostasis. We review herein the recent advances in understanding how macrophages at the center of erythroblastic islands form an erythropoietic niche that controls the terminal differentiation and maturation of erythroblasts into reticulocytes how red pulp macrophages in the spleen control iron recycling and homeostasis how these macrophages coordinate emergency erythropoiesis in response to blood loss, infections, and inflammation and how persistent infections or inflammation can lead to anemia of inflammation via macrophages. Finally, we discuss the technical challenges associated with the molecular characterization of erythroid island macrophages and red pulp macrophages.
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 11-2021
DOI: 10.1016/J.CELREP.2021.110058
Abstract: Mouse hematopoietic tissues contain abundant tissue-resident macrophages that support immunity, hematopoiesis, and bone homeostasis. A systematic strategy to characterize macrophage subsets in mouse bone marrow (BM), spleen, and lymph node unexpectedly reveals that macrophage surface marker staining emanates from membrane-bound subcellular remnants associated with unrelated cells. Intact macrophages are not present within these cell preparations. The macrophage remnant binding profile reflects interactions between macrophages and other cell types in vivo. Depletion of CD169
Publisher: Mary Ann Liebert Inc
Date: 1993
Abstract: Human umbilical cord blood CD34+ cells were purified using a two-step procedure by elimination of the soybean agglutinin-binding cells and by a positive panning selection with a CD34 monoclonal antibody. The isolated fraction was 88-97% pure CD34+ cells. A yield of 48.5% was obtained when comparing the number of cells recovered in the CD34(+)-purified fraction and the number of CD34+ cells detected in the initial mononuclear cell fraction. By flow cytometry, we observed that the CD34+ cells that were not recovered were those that had the lower expression of CD34 antigen and were therefore the more mature cells. A high recovery of CFU-GEMM progenitors (73.9%) was also observed. These data suggest the possibility of purifying CD34+ umbilical cord blood cells for clinical applications, in particular for umbilical cord blood banking.
Publisher: American Society of Hematology
Date: 07-2004
DOI: 10.1182/BLOOD-2003-05-1589
Abstract: Recent evidence suggests that protease release by neutrophils in the bone marrow may contribute to hematopoietic progenitor cell (HPC) mobilization. Matrix metalloproteinase-9 (MMP-9), neutrophil elastase (NE), and cathepsin G (CG) accumulate in the bone marrow during granulocyte colony-stimulating factor (G-CSF) treatment, where they are thought to degrade key substrates including vascular cell adhesion molecule-1 (VCAM-1) and CXCL12. To test this hypothesis, HPC mobilization was characterized in transgenic mice deficient in one or more hematopoietic proteases. Surprisingly, HPC mobilization by G-CSF was normal in MMP-9–deficient mice, NE × CG-deficient mice, or mice lacking dipeptidyl peptidase I, an enzyme required for the functional activation of many hematopoietic serine proteases. Moreover, combined inhibition of neutrophil serine proteases and metalloproteinases had no significant effect on HPC mobilization. VCAM-1 expression on bone marrow stromal cells decreased during G-CSF treatment of wild-type mice but not NE × CG-deficient mice, indicating that VCAM-1 cleavage is not required for efficient HPC mobilization. G-CSF induced a significant decrease in CXCL12α protein expression in the bone marrow of Ne × CG-deficient mice, indicating that these proteases are not required to down-regulate CXCL12 expression. Collectively, these data suggest a complex model in which both protease-dependent and -independent pathways may contribute to HPC mobilization.
Publisher: Springer Science and Business Media LLC
Date: 06-2013
DOI: 10.1038/NM.3231
Publisher: Ferrata Storti Foundation (Haematologica)
Date: 28-08-2012
Publisher: Elsevier BV
Date: 09-2021
Publisher: American Society of Hematology
Date: 12-07-2012
DOI: 10.1182/BLOOD-2012-05-431148
Abstract: In this issue of Blood, Bromberg et al and Greenbaum et al delete the gene encoding the cell adhesion molecule N-cadherin in osteoblastic cells forming the hematopoietic stem cell (HSC) niche to demonstrate that N-cadherin has no role in regulating hematopoiesis.
Publisher: American Society for Clinical Investigation
Date: 15-01-2003
DOI: 10.1172/JCI15994
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.BBMT.2008.02.003
Abstract: The recent explosion in the understanding of the cellular and molecular mechanisms underlying hematopoietic stem and progenitor cell (HSPC) mobilization has facilitated development of novel therapeutic agents, targeted at improving mobilization kinetics as well as HSPC yield. With the development of new agents comes the challenge of choosing efficient and relevant preclinical studies for the testing of the HSPC mobilization efficacy of these agents. This article reviews the use of the mouse as a convenient small animal model of HSPC mobilization and transplantation, and outlines the range of murine assays that can be applied to assess novel HSPC mobilizing agents. Techniques to demonstrate murine HSPC mobilization are discussed, as well as the role of murine assays to confirm human HSPC mobilization, and techniques to investigate the biologic phenotype of HSPC mobilized by these novel agents. Technical aspects regarding mobilization regimens and control arms, and choice of experimental animals are also discussed.
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.SEMCDB.2016.08.010
Abstract: Inflammation is a natural part of wound healing but it can also cause secondary (bystander) damage and/or negatively interfere with endogenous repair mechanisms if non-resolving. Regulation of inflammation is traditionally looked at from the perspective of danger signals, cytokines and chemokines, and their respective receptors. A neuronal contribution to the regulation of inflammation is, however, increasingly appreciated, and this has important implications for the bodily response under conditions where the nervous system itself may be damaged. In this review article, we provide an up-to-date overview of the current literature on neural innervation of primary and secondary lymphoid organs, focusing in particular on the bone marrow and spleen, its significance in relation to immune function and, lastly, also briefly discussing how a major neurotraumatic event like spinal cord injury (SCI) may impact on this.
Location: Australia
Start Date: 2011
End Date: 12-2011
Amount: $330,000.00
Funder: Australian Research Council
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