Bone Marrow Endothelial Cell Support of Primitive Hematopoietic Cells

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3573-3573
Author(s):  
Xiaoying Zhou ◽  
Dilani Rosa ◽  
Cynthia Cunningham ◽  
Gregor B. Adams

Abstract Hematopoietic stem cells (HSCs) in the bone marrow (BM) reside in specialized microenvironments known as the stem cell niche. Many reports have found the HSCs to be resident next to the endosteal surface of bone where cells of the osteoblastic lineage are a key component of the so-called endosteal niche. However, HSCs have also been found to reside adjacent to sinusoidal blood vessels. These observations have led to the proposal that HSCs in the adult BM may also reside in a vascular niche. However, the functional role of the vascular niche in hematopoiesis remains to be determined. We wished to evaluate the role that BM endothelial cells (BMECs) play in HSC physiology. To examine this we cultured BMEC-enriched cells in vitro, identified by expression of CD31, Tie-2, VE-cadherin and LDL uptake. We compared these cells to spleen derived ECs and BM stromal cells (BMSCs) in their ability to support primitive hematopoietic cells for extended periods in in vitro culture. We found that BMECs were superior in their ability to support the cobblestone area forming cell activity of VEGF-R1+ HSCs than spleen ECs or BMSCs. We also found that the number of cobblestone area cells was markedly reduced when VEGF-R1− HSCs were cultured on any of the supportive cell layers, however this may be due to an intrinsic difference between these cells as a much higher proportion of VEGF-R1+ HSCs were found to be in the G0 phase of the cell cycle than VEGF-R1− cells. To evaluate the supportive role of BMECs, spleen ECs or BMSCs on hematopoietic progenitor cells (HPC) we cultured purified primitive cells on these supportive layers and the total number of colony-forming unit-culture (CFU-C) cells were examined after 4-days or 7-days co-culture with the feeder cells. The results showed that BMECs or spleen ECs can promote the generation of CFU-C from VEGFR1+ HSCs or VEGFR1− HSCs, yet the tot al number of CFU-C produced from VEGFR1+ HSCs was greater than that from VEGFR1- HSCs. However, both of these cell types were able to support the generation of CFU-Cs to a greater degree than BMSCs. To examine the mechanism of enhanced support of VEGF-R1+ HSCs by the BMECs, we performed real-time PCR analysis for the expression of the VEGF-R1 ligands. Both BMECs and spleen ECs were found to express VEGF-A and –B to similar levels, however the expression of placental growth factor was higher in the BMECs. Whether the increased expression of this factor plays a functional role in the support of the HSCs in currently being evaluated. Our findings suggest that the ECs from BM or spleen can promote the proliferation of hematopoietic progenitor cells, while BMECs can maintain the long-term culture of VEGFR1+ HSCs in vitro. The functional relevance of this in vivo is currently being investigated.

Blood ◽  
1994 ◽  
Vol 83 (9) ◽  
pp. 2436-2443 ◽  
Author(s):  
MC Yoder ◽  
VE Papaioannou ◽  
PP Breitfeld ◽  
DA Williams

Abstract The mechanisms involved in the induction of yolk sac mesoderm into blood islands and the role of visceral endoderm and mesoderm cells in regulating the restricted differentiation and proliferation of hematopoietic cells in the yolk sac remain largely unexplored. To better define the role of murine yolk sac microenvironment cells in supporting hematopoiesis, we established cell lines from day-9.5 gestation murine yolk sac visceral endoderm and mesoderm layers using a recombinant retrovirus vector containing Simian virus 40 large T- antigen cDNA. Obtained immortalized cell lines expressed morphologic and biosynthetic features characteristic of endoderm and mesoderm cells from freshly isolated yolk sacs. Similar to the differentiation of blood island hematopoietic cells in situ, differentiation of hematopoietic progenitor cells in vitro into neutrophils was restricted and macrophage production increased when bone marrow (BM) progenitor cells were cultured in direct contact with immortalized yolk sac cell lines as compared with culture on adult BM stromal cell lines. Yolk sac- derived cell lines also significantly stimulated the proliferation of hematopoietic progenitor cells compared with the adult BM stromal cell lines. Thus, yolk sac endoderm- and mesoderm-derived cells, expressing many features of normal yolk sac cells, alter the growth and differentiation of hematopoietic progenitor cells. These cells will prove useful in examining the cellular interactions between yolk sac endoderm and mesoderm involved in early hematopoietic stem cell proliferation and differentiation.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2674-2674
Author(s):  
Seiji Fukuda ◽  
Hal E. Broxmeyer ◽  
Louis M. Pelus

Abstract The Flt3 receptor tyrosine kinase (Flt3) is expressed on primitive normal and transformed hematopoietic cells and Flt3 ligand (FL) facilitates hematopoietic stem cell mobilization in vivo. The CXC chemokine SDF-1α(CXCL12) attracts primitive hematopoietic cells to the bone marrow microenvironment while disruption of interaction between SDF-1α and its receptor CXCR4 within bone marrow may facilitate their mobilization to the peripheral circulation. We have previously shown that Flt3 ligand has chemokinetic activity and synergistically increases migration of CD34+ cells and Ba/F3-Flt3 cells to SDF-1α in short-term migration assays; this was associated with synergistic phosphorylation of MAPKp42/p44, CREB and Akt. Consistent with these findings, over-expression of constitutively active ITD (internal tandem duplication) Flt3 found in patients with AML dramatically increased migration to SDF-1α in Ba/F3 cells. Since FL can induce mobilization of hematopoietic stem cells, we examined if FL could antagonize SDF-1α/CXCR4 function and evaluated the effect of FL on in vivo homing of normal hematopoietic progenitor cells. FL synergistically increased migration of human RS4;11 acute leukemia cells, which co-express wild-type Flt3 and CXCR4, to SDF-1α in short term migration assay. Exogenous FL had no effect on SDF-1α induced migration of MV4-11 cells that express ITD-Flt3 and CXCR4 however migration to SDF-1α was partially blocked by treatment with the tyrosine kinase inhibitor AG1296, which inhibits Flt3 kinase activity. These results suggest that FL/Flt3 signaling positively regulates SDF-1α mediated chemotaxis of human acute leukemia cells in short-term assays in vitro, similar to that seen with normal CD34+ cells. In contrast to the enhancing effect of FL on SDF-1α, prolonged incubation of RS4;11 and THP-1 acute myeloid leukemia cells, which also express Flt3 and CXCR4, with FL for 48hr, significantly inhibited migration to SDF-1α, coincident with reduction of cell surface CXCR4. Similarly, prolonged exposure of CD34+ or Ba/F3-Flt3 cells to FL down-regulates CXCR4 expression, inhibits SDF-1α-mediated phosphorylation of MAPKp42/p44, CREB and Akt and impairs migration to SDF-1α. Despite reduction of surface CXCR4, CXCR4 mRNA and intracellular CXCR4 in Ba/F3-Flt3 cells were equivalent in cells incubated with or without FL, determined by RT-PCR and flow cytometry after cell permeabilization, suggesting that the reduction of cell surface CXCR4 expression is due to accelerated internalization of CXCR4. Furthermore, incubation of Ba/F3-Flt3 cells with FL for 48hr or over-expression of ITD-Flt3 in Ba/F3 cells significantly reduced adhesion to VCAM1. Consistent with the negative effect of FL on in vitro migration and adhesion to VCAM1, pretreatment of mouse bone marrow cells with 100ng/ml of FL decreased in vivo homing of CFU-GM to recipient marrow by 36±7% (P<0.01), indicating that FL can negatively regulate in vivo homing of hematopoietic progenitor cells. These findings indicate that short term effect of FL can provide stimulatory signals whereas prolonged exposure has negative effects on SDF-1α/CXCR4-mediated signaling and migration and suggest that the FL/Flt3 axis regulates hematopoietic cell trafficking in vivo. Manipulation of SDF-1α/CXCR4 and FL/Flt3 interaction could be clinically useful for hematopoietic cell transplantation and for treatment of hematopoietic malignancies in which both Flt3 and CXCR4 are expressed.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1285-1285
Author(s):  
Jianhua Wang ◽  
Russell Taichman ◽  
Younghun Jung ◽  
Aaron Havens ◽  
Yanxi Sun ◽  
...  

Abstract Osteoblasts constitute part of the stromal cell support system in marrow for hematopoiesis, however little is known as to how they interact with hematopoietic stem cells (HSCs). In vitro studies have demonstrated that the survival of HSCs in co-culture with osteoblasts requires intimate cell-to-cell contact. This suggests that the osteoblast-derived factor(s) that supports stem cell activities are either produced in very small quantities, are rapidly turned over, may be membrane-anchored and/or requires the engagement of cell-cell adhesion molecules yet to be determined. In the present report we found that survival of hematopoietic progenitor cells on osteoblasts is dependent upon the engagement of VLA-4 (α4β1) and VLA-5 (α5ß1) receptors using function blocking antibodies. Surprisingly, cell-to-cell contact is not absolutely required to support progenitor activity, but does not require receptor-ligand engagement of the VLA-4 and LFA-1 complexes, which can in part be replaced through the use of recombinant ligands (fibronectin, ICAM-1, VCAM-1). Moreover conditioned once these receptors were engaged, medium derived from HSCs grown on osteoblasts ligands supported significantly greater hematopoietic progenitors in vitro than did osteoblast-conditioned or HSC-conditioned medium alone. As an initial attempt to identify the activity we examined which genes are activated following the establishment of osteoblast-CD34+ cell co-cultures nine separate co-cultures were establsihed and the RNA was pooled and analyized on Affymetrix HG-U133A chips at 24 hours. Initially our analysis revealed that there were 259 genes that are up regulated at 24 hours, and 14 genes that are down regulated. Inspection revealed that 30 of these signals were repeated at least once suggesting that 206 genuine gene candidates were differentially expressed resulting from the co-culture. A significant proportion of the differentially expressed cDNAs represent intracellular signaling ligands 16.5% (n=34) and cell surface receptors 13.5% (n=28). Molecules associated with assembly of the extra cellular matrix or its degradation comprised 7.2% (n=15) of the differentially up regulated molecules. Molecules associated with intracellular signaling, novel sequences and intermediate metabolism comprised the majority of the remaining activities. Amoung the candidates of extra cellular signaling molecules, we noted that IL-6, LIF, MIP-1alpha and SDF-1 were identified in the microarray analysis. This observation was most gratifying as we had previously reported that IL-6, LIF and MIP-1α activities are critical components of an HSC-osteoblast microenvironment. Other notable cytokine messages for BMP-2, CCL7, FGF2b, GRO1α, GRO3, IGF1, IL1ß, IL-8, IL-11, LIF, PDGF-D and the receptors for CCL7 (CCR7). Elevations in mRNA for fibronectin, lysine hydroxylase-like proteins, laminin and Type I collagen suggest that the presence of hematopoietic cells also induces osteoblastic activities. While the identity of those molecules present in the co-cultured medium remain to be identified, the data suggests that hematopoietic cells cooperate with osteoblasts to assemble the various marrow microenvironments by directing the synthesis of osteoblast-derived cytokines to improve HSC survival.


Blood ◽  
2000 ◽  
Vol 96 (6) ◽  
pp. 2074-2080 ◽  
Author(s):  
Nobuyuki Onai ◽  
Yan-yun Zhang ◽  
Hiroyuki Yoneyama ◽  
Toshio Kitamura ◽  
Sho Ishikawa ◽  
...  

Both SDF-1 and CXCR4 disruption are lethal to mice at the embryonic stage and cause abnormalities in B lymphopoiesis, myelopoiesis, cardiogenesis, vasculogenesis, and cerebellar development. To investigate the role of SDF-1 and CXCR4 in hematopoiesis during the adult stage, mice reconstituted with bone marrow–derived hematopoietic progenitor cells transduced with either the SDF-1 or a genetically modified SDF-1–intrakine gene using a retroviral expression vector were analyzed. Flow cytometric (FCM) analysis showed a dramatic reduction of CXCR4 expression on the cells of intrakine-transduced mice, whereas CCR7 and CCR1 expression was unchanged or marginally decreased on splenocytes. Migration of splenocytes and bone marrow cells to SDF-1 was markedly suppressed in intrakine-transduced mice. FCM analysis of bone marrow cells of intrakine-transduced mice exhibited decreased numbers of pro-B (B220+ CD43+), pre-B (B220+CD43−), and immature B (B220+IgM+) cells and a decreased number of granulocytes/myeloid (Gr1+ CD11b+) cells. Impaired B lymphopoiesis and myelopoiesis in intrakine-transduced mice were confirmed by an in vitro colony-forming assay of bone marrow cells. In contrast, B lymphopoiesis and myelopoiesis were enhanced in SDF-1–transduced mice. Interestingly, T-cell maturation in the thymus was impaired both in intrakine- and SDF-1–transduced mice, suggesting that SDF-1 and CXCR4 play an important role in T lymphopoiesis as well as in B lymphopoiesis and myelopoiesis in adults. These results demonstrate an essential role of CXCR4 and its ligand SDF-1 in adult hematopoiesis, and they indicate the intrakine method as a powerful tool for functional analysis of chemokines/chemokine receptors in vivo and as a potential therapeutic approach for acquired immunodeficiency syndrome.


Blood ◽  
2000 ◽  
Vol 96 (6) ◽  
pp. 2074-2080 ◽  
Author(s):  
Nobuyuki Onai ◽  
Yan-yun Zhang ◽  
Hiroyuki Yoneyama ◽  
Toshio Kitamura ◽  
Sho Ishikawa ◽  
...  

Abstract Both SDF-1 and CXCR4 disruption are lethal to mice at the embryonic stage and cause abnormalities in B lymphopoiesis, myelopoiesis, cardiogenesis, vasculogenesis, and cerebellar development. To investigate the role of SDF-1 and CXCR4 in hematopoiesis during the adult stage, mice reconstituted with bone marrow–derived hematopoietic progenitor cells transduced with either the SDF-1 or a genetically modified SDF-1–intrakine gene using a retroviral expression vector were analyzed. Flow cytometric (FCM) analysis showed a dramatic reduction of CXCR4 expression on the cells of intrakine-transduced mice, whereas CCR7 and CCR1 expression was unchanged or marginally decreased on splenocytes. Migration of splenocytes and bone marrow cells to SDF-1 was markedly suppressed in intrakine-transduced mice. FCM analysis of bone marrow cells of intrakine-transduced mice exhibited decreased numbers of pro-B (B220+ CD43+), pre-B (B220+CD43−), and immature B (B220+IgM+) cells and a decreased number of granulocytes/myeloid (Gr1+ CD11b+) cells. Impaired B lymphopoiesis and myelopoiesis in intrakine-transduced mice were confirmed by an in vitro colony-forming assay of bone marrow cells. In contrast, B lymphopoiesis and myelopoiesis were enhanced in SDF-1–transduced mice. Interestingly, T-cell maturation in the thymus was impaired both in intrakine- and SDF-1–transduced mice, suggesting that SDF-1 and CXCR4 play an important role in T lymphopoiesis as well as in B lymphopoiesis and myelopoiesis in adults. These results demonstrate an essential role of CXCR4 and its ligand SDF-1 in adult hematopoiesis, and they indicate the intrakine method as a powerful tool for functional analysis of chemokines/chemokine receptors in vivo and as a potential therapeutic approach for acquired immunodeficiency syndrome.


Blood ◽  
1994 ◽  
Vol 83 (9) ◽  
pp. 2436-2443 ◽  
Author(s):  
MC Yoder ◽  
VE Papaioannou ◽  
PP Breitfeld ◽  
DA Williams

The mechanisms involved in the induction of yolk sac mesoderm into blood islands and the role of visceral endoderm and mesoderm cells in regulating the restricted differentiation and proliferation of hematopoietic cells in the yolk sac remain largely unexplored. To better define the role of murine yolk sac microenvironment cells in supporting hematopoiesis, we established cell lines from day-9.5 gestation murine yolk sac visceral endoderm and mesoderm layers using a recombinant retrovirus vector containing Simian virus 40 large T- antigen cDNA. Obtained immortalized cell lines expressed morphologic and biosynthetic features characteristic of endoderm and mesoderm cells from freshly isolated yolk sacs. Similar to the differentiation of blood island hematopoietic cells in situ, differentiation of hematopoietic progenitor cells in vitro into neutrophils was restricted and macrophage production increased when bone marrow (BM) progenitor cells were cultured in direct contact with immortalized yolk sac cell lines as compared with culture on adult BM stromal cell lines. Yolk sac- derived cell lines also significantly stimulated the proliferation of hematopoietic progenitor cells compared with the adult BM stromal cell lines. Thus, yolk sac endoderm- and mesoderm-derived cells, expressing many features of normal yolk sac cells, alter the growth and differentiation of hematopoietic progenitor cells. These cells will prove useful in examining the cellular interactions between yolk sac endoderm and mesoderm involved in early hematopoietic stem cell proliferation and differentiation.


Blood ◽  
1996 ◽  
Vol 88 (10) ◽  
pp. 3774-3784 ◽  
Author(s):  
F Morel ◽  
SJ Szilvassy ◽  
M Travis ◽  
B Chen ◽  
A Galy

The CD34 antigen is expressed on most, if not all, human hematopoietic stem cells (HSCs) and hematopoietic progenitor cells, and its use for the enrichment of HSCs with repopulating potential is well established. However, despite homology between human and murine CD34, its expression on subsets of primitive murine hematopoietic cells has not been examined in full detail. To address this issue, we used a novel monoclonal antibody against murine CD34 (RAM34) to fractionate bone marrow (BM) cells that were then assayed in vitro and in vivo with respect to differing functional properties. A total of 4% to 17% of murine BM cells expressed CD34 at intermediate to high levels, representing a marked improvement over the resolution obtained with previously described polyclonal anti-CD34 antibodies. Sixty percent of CD34+ BM cells lacked lineage (Lin) markers expressed on mature lymphoid or myeloid cells. Eighty-five percent of Sca-1+Thy-1(10)Lin- /10 cells that are highly enriched in HSCs expressed intermediate, but not high, levels of CD34 antigen. The remainder of these phenotypically defined stem cells were CD34-. In vitro colony-forming cells, day-8 and -12 spleen colony-forming units (CFU-S), primitive progenitors able to differentiate into B lymphocytes in vitro or into T lymphocytes in SCID mice, and stem cells with radioprotective and competitive long-term repopulating activity were all markedly enriched in the CD34+ fraction after single-parameter cell sorting. In contrast, CD34-BM cells were depleted of such activities at the cell doses tested and were capable of only short-term B-cell production in vitro. The results indicate that a significant proportion of murine HSCs and multilineage progenitor cells express detectable levels of CD34, and that the RAM34 monoclonal antibody is a useful tool to subset primitive murine hematopoietic cells. These findings should facilitate more direct comparisons of the biology of CD34+ murine and human stem and progenitor cells.


Blood ◽  
1993 ◽  
Vol 81 (3) ◽  
pp. 801-807 ◽  
Author(s):  
T Leemhuis ◽  
D Leibowitz ◽  
G Cox ◽  
R Silver ◽  
EF Srour ◽  
...  

Chronic myeloid leukemia (CML) is a malignant disorder of the hematopoietic stem cell. It has been shown that normal stem cells coexist with malignant stem cells in the bone marrow of patients with chronic-phase CML. To characterize the primitive hematopoietic progenitor cells within CML marrow, CD34+DR- and CD34+DR+ cells were isolated using centrifugal elutriation, monoclonal antibody labeling, and flow cytometric cell sorting. Polymerase chain reaction analysis of RNA samples from these CD34+ subpopulations was used to detect the presence of the BCR/ABL translocation characteristic of CML. The CD34+DR+ subpopulation contained BCR/ABL(+) cells in 11 of 12 marrow samples studied, whereas the CD34+DR- subpopulation contained BCR/ABL(+) cells in 6 of 9 CML marrow specimens. These cell populations were assayed for hematopoietic progenitor cells, and individual hematopoietic colonies were analyzed by PCR for their BCR/ABL status. Results from six patients showed that nearly half of the myeloid colonies cloned from CD34+DR- cells were BCR/ABL(+), although the CD34+DR- subpopulation contained significantly fewer BCR/ABL(+) progenitor cells than either low-density bone marrow (LDBM) or the CD34+DR+ fraction. These CD34+ cells were also used to establish stromal cell-free long-term bone marrow cultures to assess the BCR/ABL status of hematopoietic stem cells within these CML marrow populations. After 28 days in culture, three of five cultures initiated with CD34+DR- cells produced BCR/ABL(-) cells. By contrast, only one of eight cultures initiated with CD34+DR+ cells were BCR/ABL(-) after 28 days. These results indicate that the CD34+DR- subpopulation of CML marrow still contains leukemic progenitor cells, although to a lesser extent than either LDBM or CD34+DR+ cells.


Blood ◽  
1993 ◽  
Vol 82 (5) ◽  
pp. 1436-1444 ◽  
Author(s):  
Y Shiota ◽  
JG Wilson ◽  
K Harjes ◽  
ED Zanjani ◽  
M Tavassoli

Abstract The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells.


Blood ◽  
1993 ◽  
Vol 81 (3) ◽  
pp. 801-807 ◽  
Author(s):  
T Leemhuis ◽  
D Leibowitz ◽  
G Cox ◽  
R Silver ◽  
EF Srour ◽  
...  

Abstract Chronic myeloid leukemia (CML) is a malignant disorder of the hematopoietic stem cell. It has been shown that normal stem cells coexist with malignant stem cells in the bone marrow of patients with chronic-phase CML. To characterize the primitive hematopoietic progenitor cells within CML marrow, CD34+DR- and CD34+DR+ cells were isolated using centrifugal elutriation, monoclonal antibody labeling, and flow cytometric cell sorting. Polymerase chain reaction analysis of RNA samples from these CD34+ subpopulations was used to detect the presence of the BCR/ABL translocation characteristic of CML. The CD34+DR+ subpopulation contained BCR/ABL(+) cells in 11 of 12 marrow samples studied, whereas the CD34+DR- subpopulation contained BCR/ABL(+) cells in 6 of 9 CML marrow specimens. These cell populations were assayed for hematopoietic progenitor cells, and individual hematopoietic colonies were analyzed by PCR for their BCR/ABL status. Results from six patients showed that nearly half of the myeloid colonies cloned from CD34+DR- cells were BCR/ABL(+), although the CD34+DR- subpopulation contained significantly fewer BCR/ABL(+) progenitor cells than either low-density bone marrow (LDBM) or the CD34+DR+ fraction. These CD34+ cells were also used to establish stromal cell-free long-term bone marrow cultures to assess the BCR/ABL status of hematopoietic stem cells within these CML marrow populations. After 28 days in culture, three of five cultures initiated with CD34+DR- cells produced BCR/ABL(-) cells. By contrast, only one of eight cultures initiated with CD34+DR+ cells were BCR/ABL(-) after 28 days. These results indicate that the CD34+DR- subpopulation of CML marrow still contains leukemic progenitor cells, although to a lesser extent than either LDBM or CD34+DR+ cells.


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