Fibrinogen Enhances Homing-Related Responses of CD34+ by Incorporating Membrane Type1-Matrix Metalloproteinase into Membrane Lipid Rafts.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3188-3188
Author(s):  
Neeta Shirvaikar ◽  
A. Robert Turner ◽  
Mariusz Z. Ratajczak ◽  
Anna Janowska-Wieczorek
Keyword(s):  
Lipid Rafts ◽  
Stromal Cells ◽  
Leading Edge ◽  
Membrane Lipid ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Chemokine Gradient ◽  
Cord Blood Cells ◽  
First Time ◽  
Mobilized Peripheral Blood

Abstract Clinical studies have shown that transplanted mobilized peripheral blood (mPB) hematopoietic stem/progenitor cells (HSPC) home faster to the bone marrow (BM) than harvested BM or cord blood cells. We previously showed that fibrinogen has a priming effect on HSPC homing by enhancing the chemotactic responses of CD34+ cells towards a low SDF-1 gradient by incorporating CXCR4 into membrane lipid rafts (Blood2005; 105:40). In this study we further investigated the mechanism of priming by determining the effect of fibrinogen on matrix metalloproteinases (MMPs) expressed by CD34+ cells, particularly MT1-MMP which is localized on the leading edge of migrating cells and not only activates latent MMPs but by itself degrades several extracellular matrix (ECM) components such as collagens, laminin, fibrin and fibronectin. We found that fibrinogen highly upregulated MT1-MMP protein expression (Western blot) in CD34+ cells as well as proMMP-2 and proMMP-9 secretion (zymography); primed trans-Matrigel chemoinvasion of CD34+ cells towards a low SDF-1 gradient (20 ng/mL), which was inhibited by epigallocatechin-3-gallate, a potent inhibitor of MT1-MMP; and stimulated MMP-2 activation in co-cultures of stromal cells (BM fibroblasts and HUVEC) with CD34+ cells. Moreover, we demonstrate by confocal microscopy, for the first time, that in CD34+ cells MT1-MMP is localized in the GM1-fraction of lipid rafts where it co-localizes with CXCR4; this co-localization is enhanced when CD34+ cells are stimulated with fibrinogen. Furthermore, disruption of lipid raft formation by the cholesterol-depleting agent methyl-b-cyclodextrin inhibited MT1-MMP incorporation into membrane lipid rafts and also trans-Matrigel chemoinvasion of CD34+ cells towards an SDF-1 gradient. Thus we conclude that fibrinogen enhances homing-related responses of CD34+ cells towards SDF-1 by increased incorporation and co-localization of CXCR4 and MT1-MMP in membrane lipid rafts. Further, we postulate that while the presence of CXCR4 in lipid rafts allows the cells to better sense the SDF-1 chemokine gradient, the upregulated MT1-MMP in the lipid rafts facilitates their migration through the ECM and possibly towards the BM niches.

Upregulation of MT1-MMP by Molecules Present in Leukaphereis Products Primes CD34+ Cell Homing.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5273-5273
Author(s):  
Neeta Shirvaikar ◽  
Jencet Montano ◽  
A.Robert Turner ◽  
Mariusz Z. Ratajczak ◽  
Anna Janowska-Wieczorek
Keyword(s):  
Lipid Rafts ◽  
Leading Edge ◽  
Membrane Lipid ◽  
Rt Pcr ◽  
Hematopoietic Stem ◽  
Cell Homing ◽  
Mmp Inhibitor ◽  
Cd34 Cells ◽  
Mobilized Peripheral Blood ◽  
Stimulation Of

Abstract Hematopoietic stem/progenitor cells (HSPC) derived from mobilized peripheral blood engraft faster than those from bone marrow (BM) or cord blood (CB). We recently postulated that leukapheresis product supernatants (collected from G-CSF-mobilized patients) and their components (fibrinogen, fibronectin, thrombin, hyaluronic acid (HA) and C3 cleavage fragments) have a priming effect on HSPC homing by enhancing chemotactic responses to SDF-1 through increased incorporation of CXCR4 into membrane lipid rafts and stimulation of matrix metalloproteinase (proMMP-2 and proMMP-9) secretion in these cells (Blood2005; 105:40). As MT1-MMP has been shown to activate latent forms of MMP-2 and (indirectly) MMP-9 and is known to localize proteolytic activity at the leading edge of migrating cells, we decided to investigate MT1-MMPs’ role in the priming of HSPC homing. We observed that stimulation of BM and CB CD34+ cells with priming agents (HA, fibrinogen or thrombin) not only increased secretion of proMMP-2 and proMMP-9 (zymography) but also highly upregulated levels of MT1-MMP transcript (RT-PCR) and protein (Western blotting) in these cells. Moreover, trans-Matrigel chemoinvasion of CD34+ cells towards a low SDF-1 gradient (20 ng/mL), enhanced by priming agents, was inhibited by the potent MT1-MMP inhibitor epigallocatechin-3-gallate. Furthermore, priming agents (HA, fibrinogen and thrombin) increased levels of active MMP-2 in co-cultures of stromal cells (endothelial cells and BM fibroblasts) with CD34+ cells. To elucidate the mechanism of MT1-MMP upregulation by priming agents, we evaluated whether they affected MT1-MMP incorporation in ganglioside M1-enriched membrane lipid rafts in the same way as for CXCR4. We found that stimulation of hematopoietic and THP-1 cells with HA, fibrinogen and thrombin increased incorporation of MT1-MMP into membrane lipid rafts and these observations were confirmed using confocal microscopy. Hence it appears that MT1-MMP, like CXCR4, localizes in membrane lipid rafts, and this is enhanced by priming agents, leading to better homing of HSPC.

MT1-MMP Associates with Membrane Lipid Rafts and Is Required for G-CSF-Induced Hematopoietic Stem/Progenitor Cell Mobilization.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3536-3536
Author(s):  
Neeta Shirvaikar ◽  
Leah A. Marquez-Curtis ◽  
Andrew Shaw ◽  
A. Robert Turner ◽  
Anna Janowska-Wieczorek
Keyword(s):  
Flow Cytometry ◽  
Steady State ◽  
Western Blot ◽  
Lipid Rafts ◽  
Stromal Cells ◽  
Hematopoietic Cells ◽  
Membrane Lipid ◽  
Rt Pcr ◽  
Hematopoietic Stem ◽  
Cd34 Cells

Abstract Abstract 3536 Poster Board III-473 Hematopoietic stem/progenitor cells (HSPC) that have been mobilized from bone marrow (BM) to peripheral blood (PB) by granulocyte-colony stimulating factor (G-CSF) are being used for autologous and allogeneic transplantation. However, the molecular mechanisms of HSPC mobilization are not completely understood. The key molecules and interactions that regulate HSPC mobilization include various adhesion molecules, chemokine stromal cell-derived factor (SDF)-1 and its receptor CXCR4, and proteases including the soluble matrix metalloproteinase (MMP)-9. Membrane type (MT)-1 MMP, which is localized on the leading edge of migrating cells, has strong pericellular proteolytic activity, activates the latent MMPs especially proMMP-2, and has been implicated in mediating migration of tumor cells, monocytes, endothelial as well as CD34+ HSPC. MT1-MMP not only degrades several extracellular matrix molecules in the pericellular space, but also cleaves cell surface molecules such as CXCR4 and CD44, cytokines, and chemokines including SDF-1. In this study we focused on characterizing the role of MT1-MMP during G-CSF-induced migration, its regulation and subcellular localization in HSPC and mature cells. We found that MT1-MMP mRNA and protein expression (as determined by RT-PCR and flow cytometry) in G-CSF-mobilized mature hematopoietic cells (monocytes and neutrophils) as well as immature CD34+ cells was significantly higher than in their steady-state BM counterparts. Moreover, G-CSF stimulation (i) upregulated MT1-MMP transcription (RT-PCR) and protein synthesis (flow cytometry, Western blot, and confocal microscopy) in BM MNC and CD34+ cells but not in BM stromal cells; and (ii) increased their trans-Matrigel chemoinvasion towards an SDF-1 gradient which was inhibited by the MT1-MMP inhibitor epigallocatechin 3-gallate, by anti-MT1-MMP mAb, and by siRNA silencing of MT1-MMP. To determine the effect of high MT1-MMP expression in hematopoietic cells on the BM microenvironment we co-cultured steady-state BM CD34+ cells with BM fibroblasts. Zymographic analysis of the cell-conditioned media revealed that activation of proMMP-2 occurs only when the co-cultures were stimulated with G-CSF indicating that upregulation of MT1-MMP in CD34+ cells is necessary for proMMP-2 activation as media conditioned by CD34+ cells (silenced with MT1-MMP siRNA) co-cultured with stromal cells did not show proMMP-2 activation. We next focused on determining the signaling pathways that regulate MT1-MMP expression and localization in hematopoietic cells including HSPC during G-CSF-induced migration. We found that although G-CSF activated both phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways (Western blot), upregulation of MT1-MMP by G-CSF, and proMMP-2 activation were PI3K-dependent. Moreover, we demonstrated for the first time that G-CSF incorporated MT1-MMP to membrane lipid rafts of hematopoietic cells in a PI3K-dependent manner since inhibition of this axis by PI3K inhibitor LY290042 reduced MT1-MMP incorporation, an effect not observed with the MAPK inhibitor PD98059. We further demonstrated that by disrupting raft formation using the cholesterol sequestering agent methyl-beta-cyclodextrin, PI3K phosphorylation was inhibited. Subsequently MT1-MMP incorporation into lipid rafts was abrogated resulting in reduced both proMMP-2 activation and HSPC trans-Matrigel migration. We conclude that G-CSF-induced upregulation of MT1-MMP and its incorporation into membrane lipid rafts of hematopoietic cells contributes to the activation of proMMP-2 and to the generation of a highly proteolytic microenvironment in BM, which facilitates egress of HSPC into circulation. Our results suggest that manipulating MT1-MMP expression could become a new strategy to enhance mobilization of HSPC and improve the outcome of transplantation. Disclosures: No relevant conflicts of interest to declare.

A Novel Role for Thrombin in Hematopoietic Stem/Progenitor Cell Homing.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3374-3374
Author(s):  
Neeta Shirvaikar ◽  
Ali Jalili ◽  
Mariusz Z. Ratajczak ◽  
Anna Janowska-Wieczorek
Keyword(s):  
Protein Expression ◽  
Lipid Rafts ◽  
Leading Edge ◽  
Membrane Lipid ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
And Migration ◽  
Stimulation Of

Abstract Thrombin, an important serine protease, not only plays a pivotal role in platelet aggregation and coagulation, but also through activation of its receptor, seven transmembrane, G-protein-coupled receptor PAR-1, elicits numerous cellular responses in platelets and endothelial cells such as induction of adhesion molecules, production of chemokines, activation of matrix metalloproteinase (MMP)-2, cytoskeletal reorganization and migration. Thrombin is also one of the inflammatory molecules elevated during G-CSF mobilization of hematopoietic stem/progenitor cells (HSPC) and their collection by leukapheresis. We recently reported that components of leukapheresis products including thrombin enhance in vitro chemotaxis of CD34+ cells towards an SDF-1 gradient and in vivo homing to bone marrow (BM) niches in a murine model (Blood2005; 105:40). In this study we investigated whether thrombin enhances the homing-related responses of human HSPC (CD34+ cells) through MMPs, especially membrane-type (MT)1-MMP which is known to be localized on the leading edge of migrating cells and both activates latent proMMPs (MMP-2, -9) and itself has strong pericellular proteolytic activity. We found that stimulation of CD34+ cells with thrombin upregulates mRNA for MT1-MMP and MMP-9 as well as MT1-MMP protein expression (Western blot, flow cytometry) and proMMP-2 and proMMP-9 secretion (zymography). Thrombin was also found to (i) prime trans-Matrigel chemoinvasion of CD34+ cells towards a low SDF-1 gradient (20 ng/mL), which was inhibited by epigallocatechin-3-gallate, a potent inhibitor of MT1-MMP, and (ii) activate MMP-2 in of co-cultures of CD34+ cells with stromal cells (BM fibroblasts and HUVEC) which secrete proMMP-2. We also found that SDF-1 upregulates mRNA and protein expression of MT1-MMP. Moreover, using confocal microscopy we demonstrate for the first time that in CD34+ cells, PAR-1, like CXCR4, is localized in the GM1 fraction of lipid rafts and stimulation of these cells with thrombin as well as SDF-1 increases incorporation of MT1-MMP into membrane lipid rafts. Furthermore, disruption of lipid raft formation by the cholesterol-depleting agent methyl-b-cyclodextrin inhibits MT1-MMP incorporation into membrane lipid rafts and also trans-Matrigel chemoinvasion of CD34+ cells towards SDF-1. Thus we conclude that thrombin, through PAR-1 signalling and the SDF-1-CXCR4 axis, upregulates the incorporation of MT1-MMP into membrane lipid rafts and the interaction of these axes enhances the homing-related responses of HSPC towards SDF-1.

Incorporation of CXCR4 into membrane lipid rafts primes homing-related responses of hematopoietic stem/progenitor cells to an SDF-1 gradient

Blood ◽  
2005 ◽  
Vol 105 (1) ◽  
pp. 40-48 ◽  
Author(s):  
Marcin Wysoczynski ◽  
Ryan Reca ◽  
Janina Ratajczak ◽  
Magda Kucia ◽  
Neeta Shirvaikar ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Lipid Rafts ◽  
Adhesion Molecule ◽  
Actin Polymerization ◽  
Membrane Lipid ◽  
Small Gtpase ◽  
Calcium Flux ◽  
Urokinase Plasminogen Activator Receptor ◽  
Hematopoietic Stem ◽  
Cd34 Cells

Abstract We found that supernatants of leukapheresis products (SLPs) of patients mobilized with granulocyte–colony-stimulating factor (G-CSF) or the various components of SLPs (fibrinogen, fibronectin, soluble vascular cell adhesion molecule-1 [VCAM-1], intercellular adhesion molecule-1 [ICAM-1], and urokinase plasminogen activator receptor [uPAR]) increase the chemotactic responses of hematopoietic stem/progenitor cells (HSPCs) to stromal-derived factor-1 (SDF-1). However, alone they do not chemoattract HSPCs, but they do increase or prime the cells' chemotactic responses to a low or threshold dose of SDF-1. We observed that SLPs increased calcium flux, phosphorylation of mitogen-activated protein kinase (MAPK) p42/44 and AKT, secretion of matrix metalloproteinases, and adhesion to endothelium in CD34+ cells. Furthermore, SLPs increased SDF-dependent actin polymerization and significantly enhanced the homing of human cord blood (CB)– and bone marrow (BM)–derived CD34+ cells in a NOD/SCID mouse transplantation model. Moreover, the sensitization or priming of cell chemotaxis to an SDF-1 gradient was dependent on cholesterol content in the cell membrane and on the incorporation of the SDF-1 binding receptor CXCR4 and the small GTPase Rac-1 into membrane lipid rafts. This colocalization of CXCR4 and Rac-1 in lipid rafts facilitated guanosine triphosphate (GTP) binding/activation of Rac-1. Hence, we postulate that CXCR4 could be primed by various factors related to leukapheresis and mobilization that increase its association with membrane lipid rafts, allowing the HSPCs to better sense the SDF-1 gradient. This may partially explain why HSPCs from mobilized peripheral blood leukapheresis products engraft more quickly in patients than do those from BM or CB. Based on our findings, we suggest that the homing of HSPCs is optimal when CXCR4 is incorporated in membrane lipid rafts and that ex vivo priming of HSPCs with some of the SLP-related molecules before transplantation could increase their engraftment.

Impaired Engraftment of Hematopoietic Stem/Progenitor Cells (HSPC) in Immunodefcient Mice Supports an Important Role of Complement System for Optimal Homing.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 338-338
Author(s):  
Reca Ryan ◽  
Marcin Wysoczynski ◽  
Janina Ratajczak ◽  
Mariusz Z. Ratajczak
Keyword(s):  
Progenitor Cells ◽  
Lipid Rafts ◽  
Membrane Lipid ◽  
Scid Mice ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Human Cd34 ◽  
Cell Counts ◽  
Cd34 Cells

Abstract Recently we demonstrated that conditioning for transplantation (radio-chemotherapy) activates complement (C) in bone marrow (BM) and that the third complement component (C3) cleavage fragments (C3a and desArgC3a) increase responsiveness of hematopoietic stem/progenitor cells (HSPC) to stromal-derived factor (SDF)-1 gradient by enhancing the incorporation of CXCR4 into membrane lipid rafts – what enables its better interaction with small GTPases from the Rho/Rac family (Blood2003, 101, 3784, Blood2005, 105, 40–48). Based on these data we hypothesized that C could affect the homing/engraftment of HSPC. Thus we performed transplant experiments in several strains of immunodeficient animals. First, we noticed that lethally irradiated NOD/SCID mice engrafted worse with wt HSPC as compared to wt animals (~30% decrease in a presence of donor-derived clonogeneic CFU-GM in marrow cavities 24 hrs after transplantation). This impaired engraftment correlated with the lack of C activation in BM after conditioning for transplantation by lethal irradiation. The lack of C activation in NOD/SCID mice after conditioning for transplant could be explained by a lack of IgM antibodies that activate C by classical IgM-dependent pathway. Next, to learn more on the molecular mechanisms of C cascade activation during conditioning for transplantation and the role of the C3a-C3aR axis in engraftment of HSPC we studied engraftment i) of wild type (wt) murine HSPC in immunodeficient mice (C3−/− and C3aR−/−) and ii) murine HSPC derived from C3aR−/− or C3−/− deficient mice in wild type littermates. The engraftment of HSPC was evaluated by i) recovery of peripheral blood cell counts in transplanted animals, ii) number of CFU-S colonies and iii) number of clonogeneic progenitors in marrow cavities 16 day after transplantation. We noticed that both C3−/− and C3aR−/− mice had impaired engraftment with wt HSPC. At the same time HSPC from C3aR−/− mice but not C3−/− animals showed poor engraftment in wt recipients. This suggests that i) C3aR expressed on HSPC interacts with C3a generated during C-activation in BM environment and ii) that this interaction is important for optimal homing of HSPC. To support further this notion, human CD34+ cells were exposed to nontoxic doses of C3aR antagonist SB290157 and transplanted into NOD/SCID mice. Subsequently, 24 hrs after transplantation cells were isolated from the marrow cavities and stimulated to grow human CFU-GM colonies. By employing this assay we noticed reduced engraftment of human CD34+ cells (~30%, p<0.0001) as compared to mice transplanted with control CD34+ cells unexposed to SB290157. These data allow for the following conclusions: i) C is activated in BM during conditioning for transplantation by irradiation ii) C is activated after exposure of a natural neoepitope in damaged marrow which is recognized by natural IgM activating C via the classical pathway, iii) C3 cleavage product C3a binds to C3aR on transplanted HSPC and increases incorporation of CXCR4 into membrane lipid rafts enhancing responsiveness of HSPC to an SDF-1 gradient, and finally iv) a proper interplay between the C system and SDF-1-CXCR axis ensures optimal homing of HSPC.

Upregulation of MT1-MMP Expression by Hyaluronic Acid Enhances Homing-Related Responses of Hematopoietic CD34+ Cells to an SDF-1 Gradient.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2889-2889 ◽  
Author(s):  
Neeta Shirvaikar ◽  
Jencet Montano ◽  
Andrew R. Turner ◽  
Mariusz Z. Ratajczak ◽  
Anna Janowska-Wieczorek
Keyword(s):  
Hyaluronic Acid ◽  
Leading Edge ◽  
Cell Surface Receptor ◽  
Migration And Invasion ◽  
Hematopoietic Stem ◽  
Tumor Cell Migration ◽  
Cell Engraftment ◽  
Cd34 Cells ◽  
Surface Receptor ◽  
And Migration

Abstract Hyaluronic acid (HA), the bone marrow (BM) extracellular matrix microenvironment (ECM) component, not only supports cell adhesion but also promotes migration and homing of hematopoietic stem/progenitor cells (HSPC) by interacting with its cell surface receptor CD44. CD44 has been shown to co-localize with matrix metalloproteinases (MMPs), particularly membrane-type (MT)-1 MMP and MMP-9, at the leading edge of migrating tumor cells, and the cleavage of CD44 by MT1-MMP is critical for tumor cell migration and invasion. MT1-MMP has strong pericellular proteolytic activity and also activates latent forms of MMP-2 and MMP-9. In this study we examined the effect of HA on MT1-MMP expression and migration of BM, peripheral blood and cord blood CD34+ cells. We found that HA upregulates mRNA for MT1-MMP and MMP-9, increases MT1-MMP protein (as evaluated by Western blotting) and stimulates MMP-9 and MMP-2 activity (as determined by zymography) in CD34+ cells. In chemotaxis assays HA alone did not show any chemotactic activity but primed the chemotaxis of CD34+ cells to a low SDF-1 gradient (10 ng/mL) and their trans-Matrigel chemoinvasion to a low SDF-1 gradient. Similarly, SDF-1 besides stimulating MMP-2 and MMP-9 (as we previously described in Exp Hematol2000; 28:1274), also upregulated MT1-MMP in CD34+ cells. In addition, we found that the HA enhanced activation of latent MMP-2 in co-cultures of CD34+ cells with HUVEC. In conclusion, we demonstrate for the first time that (i) HA primes CD34+ cell chemotaxis and chemoinvasion to a low SDF-1 gradient; (ii) that both HA and SDF-1 stimulate MT1-MMP, MMP-2 and MMP-9 in CD34+ cells, and (iii) HA enhances activation of proMMP-2 in the ECM. Hence the interaction of HA and SDF-1 with MT1-MMP could play an important role in HSPC migration and homing and we postulate that pretreatment of HSPC with HA before transplantation could enhance their homing by inducing expression of MMPs that is optimal for stem cell engraftment.

Muc1 Expression Identifies Human Self-Renewing Stem/Progenitor Populations and Is Elevated in AML CD34+ Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4040-4040
Author(s):  
Szabolcs Fatrai ◽  
Simon M.G.J. Daenen ◽  
Edo Vellenga ◽  
Jan J. Schuringa
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Stromal Cells ◽  
Bone Marrow Stromal Cells ◽  
Fold Increase ◽  
Marrow Stromal Cells ◽  
Muc1 Expression ◽  
Hematopoietic Stem ◽  
Cd34 Cells

Abstract Mucin1 (Muc1) is a membrane glycoprotein which is expressed on most of the normal secretory epithelial cells as well as on hematopoietic cells. It is involved in migration, adhesion and intracellular signalling. Muc1 can be cleaved close to the membrane-proximal region, resulting in an intracellular Muc1 that can associate with or activate various signalling pathway components such as b-catenin, p53 and HIF1a. Based on these properties, Muc1 expression was analysed in human hematopoietic stem/progenitor cells. Muc1 mRNA expression was highest in the immature CD34+/CD38− cells and was reduced upon maturation towards the progenitor stage. Cord blood (CB) CD34+ cells were sorted into Muc1+ and Muc1− populations followed by CFC and LTC-IC assays and these experiments revealed that the stem and progenitor cells reside predominantly in the CD34+/Muc1+ fraction. Importantly, we observed strongly increased Muc1 expression in the CD34+ subfraction of AML mononuclear cells. These results tempted us to further study the role of Muc1 overexpression in human CD34+ stem/progenitor cells. Full-length Muc1 (Muc1F) and a Muc1 isoform with a deleted extracellular domain (DTR) were stably expressed in CB CD34+ cells using a retroviral approach. Upon coculture with MS5 bone marrow stromal cells, a two-fold increase in expansion of suspension cells was observed in both Muc1F and DTR cultures. In line with these results, we observed an increase in progenitor counts in the Muc1F and DTR group as determined by CFC assays in methylcellulose. Upon replating of CFC cultures, Muc1F and DTR were giving rise to secondary colonies in contrast to empty vector control groups, indicating that self-renewal was imposed on progenitors by expression of Muc1. A 3-fold and 2-fold increase in stem cell frequencies was observed in the DTR and Muc1F groups, respectively, as determined by LTC-IC assays. To determine whether the above mentioned phenotypes in MS5 co-cultures were stroma-dependent, we expanded Muc1F and DTR-transduced cells in cytokine-driven liquid cultures. However, no proliferative advantage or increase in CFC frequencies was observed suggesting that Muc1 requires bone marrow stromal cells. In conclusion, our data indicate that HSCs as well as AML cells are enriched for Muc1 expression, and that overexpression of Muc1 in CB cells is sufficient to increase both progenitor and stem cell frequencies.

Analysis of Mesenchymal Stromal Cells (MSC) and Their Interactions with CD34 Stem and Progenitor Cells in Patients with Myelodysplastic Syndromes (MDS)

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2393-2393
Author(s):  
Stefanie Geyh ◽  
Ron Patrick Cadeddu ◽  
Julia Fröbel ◽  
Ingmar Bruns ◽  
Fabian Zohren ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Myelodysplastic Syndromes ◽  
Stromal Cells ◽  
Median Number ◽  
Lower Number ◽  
Differentiation Potential ◽  
Receptor Ligand ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Stem And Progenitor Cells

Abstract Abstract 2393 Background: Myelodysplastic syndromes (MDS) represent a heterogeneous group of hematopoietic stem cell disorders and research in this field has mainly focused on hematopoietic stem and progenitor cells (HSPC). Still, recent data from mouse models indicate that the bone marrow (BM) microenvironment might be involved in the pathogenesis MDS (Raaijmakers et al., 2010). The role of mesenchymal stromal cells (MSC) in particular as a key component of the BM microenvironment remains elusive in human MDS and data so far are controversial. Design/Methods: We therefore investigated MSC and immunomagnetically enriched CD34+ HSPC from BM of 42 untreated patients (pts) with MDS (12 RCMD, 12 RAEB, 12 sAML, 3 del5q, 1 CMML-1, 1 MDS hypocellular, 1 MDS unclassifiable according to WHO) and age-matched healthy controls (HC, n=13). MSC were examined with regard to growth kinetics, morphology and differential potential after isolation and expansion according standard procedures in line with the international consensus criteria (Dominici et al., 2006). Furthermore corresponding receptor-ligand pairs on MSC and CD34+ cells (Kitlg/c-kit; CXCL12/CXCR4; Jagged1/Notch1; Angpt1-1/Tie-2; ICAM1/LFA-1) were investigated by RT-PCR. Results: In MDS, the colony forming activity (CFU-F) of MSC was significantly reduced in comparison to HC (median number of colonies per 1×107MNC in MDS: 8, range 2–74 vs. HC: 175, 10–646, p=0.003) and this was also true when looking at the different subtypes (RCMD median: 16, p=0.04; RAEB median: 8, p=0.31; sAML median: 26, p=0.02). According to this, MSC from pts with RCMD and del5q could only be maintained in culture for a lower number of passages (median number of passages: MDS 3 passages, range 1–15; HD 14 passages, range 8–15, p=0.01), had a lower number of cumulative population doublings (CPD) and needed a longer timer to reach equivalent CPD (MDS median: 18,16 CPD, HD median: 33,68 CPD, p=0,0059). All types of MDS-MSC showed an abnormal morphology, while an impaired osteogenic differentiation potential was exclusively observed in pts with RCMD. These findings of an altered morphology together with a diminished growth and differentiation potential prompted us to test, whether the interaction between MSC and CD34+ HSPC in BM of pts with MDS was also disturbed. On the MDS-MSC, we found a significant lower expression of Angpt1 in pts with RAEB (3.5-fold, p=0.01) and del5q (4.9-fold, p=0.009) compared to HD. The expression of CXCL12 (2.5-fold, p=0.057) and jagged1 was reduced in trend in MSC from pts with MDS, while no differences were observed with regard to the expression of kitlg and ICAM1. When looking on CD34+ cells, we found a significantly reduced expression of CXCR4 (RCMD 2.5-fold, p=0.02; RAEB 2.46-fold, p=0.02), notch1 (RCMD 6-fold, p=0.04) and Tie-2 (RAEB 5.91-fold, p=0.02) in pts with MDS, while LFA-1 was overexpressed in pts with RAEB (2.6-fold, p=0.036). Conclusion: Taken together, our data indicate that MSC from pts with MDS are structurally altered and that the crosstalk between CD34+ HSPC and MSC in the BM microenvironment of pts with MDS might be deregulated as a result of an abnormal expression of relevant receptor-ligand pairs. Ongoing research is required to corroborate these findings and to definitely address their functional relevance for the pathogenesis of MDS. Disclosures: No relevant conflicts of interest to declare.

Neuropeptide Y Is Critical for Bone Marrow Stromal Cells and Hematopoietic Recovery Following Injury

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 173-173
Author(s):  
Pratibha Singh ◽  
Louis M. Pelus
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Stromal Cells ◽  
Nerve Fibers ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Hematopoietic Recovery ◽  
Donor Cells ◽  
Cd34 Cells ◽  
Stem And Progenitor Cells

Abstract Bone marrow suppression is the most common limiting side-effect of conventional cancer chemo/radio therapy and is the primary cause of morbidity/mortality after accidental exposure to a high dose of ionizing radiation. The mechanisms mediating radiation-induced hematopoietic stem and stromal cell dysfunction however are not well understood. Radiation therapy causes substantial sensory neuropathy in patients. Recent studies reveal that bone marrow cells are highly innervated by sympathetic nerve fibers and that chemotherapy induced nerve-damage can impair hematopoietic regeneration, suggesting a contribution of nerve fibers in the regulation of hematopoietic stem cell and stromal cell activities. Whether irradiation- mediated nerve injury is a crucial lesion that causes deficits in hematopoietic recovery is not known. We recently discovered that differential signaling from the neuropeptide Y (NPY) receptors on bone marrow endothelial cells regulates vascular permeability and stem cell egress. NPY is an important neurotransmitter of the sympathetic nervous system and the principal adreno-medullary hormone. In this study, we found that NPY is important for reconstitution of the bone marrow niche and hematopoietic regeneration following sublethal irradiation (650 cGy). The levels of NPY were significantly reduced in bone marrow of irradiated mice suggesting damage to nerve fibers. Treatment of wild-type mice with full length NPY (1µg/mouse/day) for 3 consecutive days after irradiation markedly reduced the loss of mesenchymal stem cells (CD45-Ter119-CD31-Nestin+PDGFR+CD51+), endothelial cells (CD45-Ter119-CD31+VE-cadherin+) and hematopoietic stem and progenitor cells (SLAM LSK and LSK) in the bone marrow and promoted faster hematopoietic recovery. In addition, pharmacological NPY treatment prevented irradiation mediated nerve fiber damage. In contrast, in NPY knockout mice, regeneration of CD45neg stromal cells, SLAM LSK and LSK cells after irradiation was significantly reduced compared to wild-type controls. This reduced hematopoietic recovery in NPY deficient mice following irradiation was associated with increased apoptosis/necrosis of stromal cells and hematopoietic stem and progenitor cells. We also examined whether NPY played an intrinsic or extrinsic role in stem cell homing. Wild-type or NPY deficient BM cells were transplanted into wild-type or NPY knockout recipients. Strikingly, the homing of wild-type donor cells into NPY deficient recipients or NPY knockout donor cells into wild-type recipients were both reduced. To explore whether NPY regulates human stem cells, we treated human cord blood CD34+ cells ex vivo with NPY for 3 days and evaluated cell expansion. Long-term culture assays demonstrated that NPY treatment enhanced the clonal expansion of CD34+ cells. In conclusion, our studies suggests that NPY plays both an intrinsic and extrinsic role in hematopoiesis and that NPY-mediated protection of the sympathetic nervous system within the bone marrow can facilitate stem cell niche regeneration and enhance regenerative hematopoiesis following irradiation/injury. Disclosures No relevant conflicts of interest to declare.

scholarly journals Characterization of the Hematopoietic Supporting Activity of Osteoblasts Derived from Bone Marrow Mesenchymal Stromal Cells

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4358-4358
Author(s):  
Manal Alsheikh ◽  
Roya Pasha ◽  
Nicolas Pineault
Keyword(s):  
Bone Marrow ◽  
Osteogenic Differentiation ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Conflicts Of Interest ◽  
Soluble Factors ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
The Impact ◽  
Myeloid Progenitors

Abstract Osteoblasts (OST) found within the endosteal niche are important regulators of Hematopoietic Stem and Progenitor Cells (HSPC) under steady state and during hematopoietic reconstitution. OST are derived from mesenchymal stromal cells (MSC) following osteogenic differentiation. MSC and OST secrete a wide array of soluble factors that sustain hematopoiesis. Recently, we showed that media conditioned with OST derived from MSC (referred as M-OST) after 6 days of osteogenic differentiation were superior to MSC conditioned media (CM) for the expansion of cord blood (CB) progenitors, and CB cells expanded with M-OST CM supported a more robust engraftment of platelets in NSG mice after transplantation. These findings raised the possibility that M-OST could be superior to MSC for the ex vivoexpansion HSPC. In this study, we set out to test the hypothesis that the growth modulatory activity of M-OST would vary as a function of their maturation status. The objectives were to first monitor the impact of M-OST differentiation and maturation status on the expression of soluble factors that promote HSPC expansion and in second, to investigate the capacity of M-OST CMs prepared from M-OST at distinct stages of differentiation to support the expansion and differentiation of HSPCs in culture. M-OST at distinct stages of differentiation were derived by culturing bone marrow MSC in osteogenic medium for various length of time (3 to 21 days). All CB CD34+ enriched (92±7% purity) cell cultures were done with serum free media conditioned or not with MSC or M-OST and supplemented with cytokines SCF, TPO and FL. We first confirmed the progressive differentiation and maturation of M-OST as a function of osteogenic culture length, which was evident by the induction of the osteogenic transcription factors Osterix, Msx2 and Runx2 mRNAs, the gradual increase in osteopontin and alkaline phosphatase positive cells and quantitative increases in calcium deposit. Next, we investigated the expression in MSC and M-OSTs of genes known to collaborate for the expansion of HSPCs by Q-PCR. Transcript copy numbers for IGFBP-2 increased swiftly during osteogenic differentiation, peaking at day-3 (˃100-fold vs MSC, n=2) and returning below MSC level by day-21. In contrast, ANGPTL members (ANGPTL-1, -2, -3 and -5) remained superior in M-OSTs throughout osteogenic differentiation with expression levels peaking around day 6 (n=2). Next, we tested the capacity of media conditioned with primitive (day-3, -6), semi-mature (day-10, -14) and mature M-OST (day-21) to support the growth of CB cells. All M-OST CMs increased (p˂0.03) the growth of total nucleated cells (TNC) after 6 days of culture compared to non-conditioned medium used as control (mean 2.0-fold, n=4). Moreover, there was a positive correlation between cell growth and M-OST maturation status though differences between the different M-OST CMs tested were not significant. The capacity of M-OST CMs to increase (mean 2-fold, n=4) the expansion of CD34+ cells was also shared by all M-OST CMs (p˂0.05), as supported by significant increases with immature day-3 (mean ± SD of 18 ± 6, p˂0.02) and mature day-21 M-OST CMs (14 ± 5, p˂0.05) vs. control (8 ± 3, n=4). Conversely, expansions of TNC and CD34+ cells in MSC CM cultures were in-between that of control and M-OST CMs cultures. Interestingly, M-OST CMs also modulated the expansion of the HSPC compartment. Indeed, while the expansion of multipotent progenitors defined as CD34+CD45RA+ was promoted in control culture (ratio of 4.5 for CD34+CD45RA+/CD34+CD45RA- cells), M-OST CMs supported greater expansion of the more primitive CD34+CD45RA- HSPC subpopulation reducing the ratio to 3.3±0.4 for M-OST cultures (cumulative mean of 10 cultures, n=2). Moreover, the expansions of CD34+CD38- cells and of the long term HSC-enriched subpopulation (CD34+CD38-CD45RA-Thy1+) in M-OST CM cultures were respectively 2.7- and 2.8-fold greater than those measured in control cultures (n=2-4). Finally, the impact of M-OST CMs on the expansion of myeloid progenitors was investigated using a colony forming assay; expansion of myeloid progenitors were superior in all M-OST CM cultures (1.6±0.2 fold, n=2). In conclusion, our results demonstrate that M-OST rapidly acquire the expression of growth factors known to promote HSPC expansion. Moreover, the capacity of M-OST CMs to support the expansion of HSPCs appears to be a property shared by M-OST at various stages of maturation. Disclosures No relevant conflicts of interest to declare.

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