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a Division of Experimental Hematology, Cincinnati Children’s Research Foundation, Cincinnati, OH, USA;
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' n, ^3 Y7 ^% K0 l* p; V# Db Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA;- t( G- w5 _- A
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c Hoxworth Blood Center, University of Cincinnati Medical Center, Cincinnati, OH, USA
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Key Words. Stem Cells ? Rho GTPase ? RAC ? Engraftment ? Homing( f# R+ A* D7 Y. M$ x
6 j$ ^" T2 o! J5 QCorrespondence: David A. Williams, M.D., Division of Experimental Hematology, Cincinnati Children’s Hospital Research Foundation, 3333 Burnet Avenue, ML 7013, Cincinnati, OH 45215. Telephone: 513-636-0364; Fax: 513-636-3768; e-mail: David.Williams@cchmc.org
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1 \+ ~' K$ _- v: s) ~ABSTRACT' v- a/ w, F3 }; ?) R: g" E( V& x
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Hematopoietic stem cells (HSC) are comprised of a pluripotent cell population residing near the endosteum of the bone medullary cavity of adult mammals . These cells are responsible for maintaining multilineage hematopoiesis by generating committed progenitors that ultimately differentiate into mature elements of the blood. HSC are also capable of self-renewal divisions that maintain the stem cell compartment throughout the lifetime of the individual . Interaction with a variety of cells, extracellular matrix components, and growth factors, making up the hematopoietic microenvironment, appears to be crucial for maintenance of the stem cell compartment . These interactions include adhesion to the mesenchymal cells, possibly osteoblasts of the bone marrow stroma that display membrane-associated growth factors such as stem cell factor (SCF) and produce extracellular matrix proteins, including collagen, laminins, and fibronectin. In addition, matrix proteins also provide a reservoir of secreted growth factors such as interleukin-3 (IL-3) and chemoattractants, such as stromal cell–derived factor-1 alpha (SDF-1), which appears to have a pivotal role in stem cell migration .
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, ~3 {# m `; q3 |2 `Adhesion receptors expressed on hematopoietic cells mediate direct contact with mesenchymal cells and matrix proteins, and are therefore, highly relevant to localization of these cells in the hematopoietic microenvironment. These same receptors may also initiate signaling pathways following adhesion . The heterodimeric beta-1 integrins, particularly the 4?1 (VLA-4) and 5?1 (VLA-5) integrins, and the adhesion molecule CD44 appear to be of critical importance for homing and localization of HSC to the hematopoietic microenvironment mediating binding to fibronectin, as well as the vascular cell adhesion molecule (VCAM-1) and proteoglycans. The localization of HSC in the hematopoietic microenvironment is of particular importance in transplantation biology and cellular therapy since after infusion or mobilization of HSC into the bloodstream these cells must translocate from the peripheral blood into the bone marrowspace. The migration of HSC into the appropriate location in the medullary cavity is thought to be a nonrandom process and is termed "homing."9 l+ _" p% g9 t V5 j: \
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Analogous to the well-described process involved in egress of leukocytes from the bloodstream, homing of HSC presumably requires a complex series of interactions with the vascular endothelium and bone marrow extracellular matrix. Leukocyte egress from the blood is initiated by capture and rolling of cells on the endothelium, then mediated via interaction of selectins on the hematopoietic cells to proteoglycans expressed on endothelial cells. This is followed by firm adhesion of these cells to the blood vessel wall via activated integrins and cytokine/chemokine/chemoattractant-induced transendothelial transmigration . For HSC this process is thought to be directed in part by SDF-1, which binds to the cellular receptor CXCR4 expressed on hematopoietic cells .
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The migration of HSC in and out of the hematopoietic microenvironment likely requires significant changes in cell shape, adhesion or de-adhesion to different ligands, and activation of directed cellular migration . In addition, it has been hypothesized that open "space" in the hematopoietic microenvironment, so-called stem cell niches, favor successful engraftment of transplanted cells . Appropriate localization of HSC in specific niches of the hematopoietic microenvironment likely requires orchestrated binding to the extracellular matrix proteins and interactions with a variety of soluble and membrane-bound growth factors .
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+ L$ X0 y+ \2 i1 VThe process of migration is regulated in many cell types by the small Rho GTPase family , and downstream effectors (reviewed by Symons ). In addition, in some cells, both integrins and growth factor receptors have been shown to transduce signals that converge on Rho GTPases, leading to cross-talk between these surface receptors . Such converging signals lead to migration of mast cells on fibronectin after stimulation by stem cell factor (SCF) via activation of Vav, a guanine exchange factor (GEF) for Rac, and subsequent Rac activation . Rho GTPases act as molecular switches by cycling between an active GTP-bound form and an inactive GDP-bound state. Upon activation via specific but multiple different receptors, GTP-bound Rho GTPases have been implicated in a variety of cellular responses that ultimately regulate significant cell shape changes. Actin polymerization leading to cytoskeleton remodeling, integrin clustering, and integrin-mediated adhesion and motility are regulated via Rho GTPases .9 R) g7 J0 Z. f& d& S/ T5 E- `! H$ l
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We previously demonstrated that the hematopoietic-specific Rac2 protein, a member of the Rac subfamily of Rho-GTPases has unique roles in blood cell development and function, including regulation of migration, phagocytosis, degranulation, and adhesion of a variety of differentiated myeloid cells . More recently, Rac2 has also been implicated in adhesion, migration, and cell shape changes of primitive HSC . Furthermore, the highly homologous Rho GTPase Rac1 has been shown to regulate both overlapping and unique functions in blood cells and HSC. The cellular changes associated with Rac deficiency lead to increased in vivo trafficking of HSC, as measured by elevated numbers of these cells in the peripheral blood of Rac2–/– mice and more dramatically in Rac1–/–; Rac2–/– cells. To date, the effect of Rac2 deficiency on homing and long-term engraftment of HSC has not been examined.
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Because adhesion is thought to play a critical part in the localization of HSC in the hematopoietic microenvironment and is defective in Rac2-deficient HSC, we hypothesized that the increased circulating HSC seen in Rac2–/– mice was associated with increased availability of stem cell niches in the medullary hematopoietic microenvironment of these mice. The experiments described here were designed to address this hypothesis by determining if wild-type (WT) HSC preferentially engraft in nonablated Rac2–/– bone marrow. Here we report that HSC from WT mice, defined both phenotypically and by secondary transplantation, display significantly higher multiline age repopulation in nonablated Rac2–/–recipients than in WT recipients. We also observe long-term defects of Rac2–/– HSC in engraftment studies. These data suggest that Rac2 has a significant physiologic role in the localization of HSC to the hematopoietic microenvironment and provides quantitative evidence of the central role of Rac GTPases in the long-term engraftment process.2 a. U1 v+ F* O5 E T
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MATERIALS AND METHODS' Z8 x9 L: F6 }+ V8 K+ N, ~
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WT HSC Preferentially Engraft in Nonablated Rac2–/– Mice7 |6 E0 `+ m5 b W
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We previously demonstrated an increase in the circulation of hematopoietic stem cells/progenitors HSC/P (day 12 colony-forming unit, spleen) in Rac2–/– mice at baseline and after stimulation with granulocyte colony-stimulating factor (G-CSF) . We hypothesized that increased circulating HSC/P would be associated with increased frequency of empty stem cell niches in the medullary cavity and that defective adhesion would be associated with a lower capacity of Rac2–/– hematopoietic stem cells (HSC) to provide long-term engraftment. To test this hypothesis, WT (CD45.1 ) low-density bone marrow (LDBM) cells were transplanted into nonablated WT or Rac2–/– (both CD45.2 ) recipients, and engraftment was followed in the peripheral blood and hematopoietic organs over 4 months. In each of three independent experiments, the number of peripheral blood cells derived from WT donor HSC/P was significantly higher in nonablated Rac2–/– recipient mice (KO), than in WT recipient mice (Fig. 1A). These differences occurred despite similar total bone marrow cellularity of naive WT and Rac2–/– mice (data not shown). WT donor engraftment in Rac2–/– recipients remained significantly higher at all time points analyzed, reaching a maximum level of 8- to 10-fold higher in Rac2–/– recipients than in WT recipients at 4 months. These data suggest a more pronounced defect in the primitive stem cell compartment of these mice compared with the progenitor compartment, which gives rise to blood cells early and transiently after engraftment. WT donor cells contributed to multilineage reconstitution in the blood of recipient mice (Fig. 1C), suggesting a defect in multipotential HSC/P in Rac2–/– mice. Engraftment of WT cells was also significantly higher in all other hematopoietic organs examined at 4 months in Rac2–/– mice compared with WT mice, including bone marrow, spleen, and lymph nodes (Fig. 1B)./ I/ d: ?' t5 I& v7 [
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Figure 1. Engraftment and lineage contribution of donor-derived LDBM cells in nonablated recipient mice. In Figure 1A to 1C, data for transplantation of WT (CD45.1 ) donor cells into nonablated WT or Rac2–/– (KO) recipient mice are shown, while Figure 1D and 1E represent data from transplantation of WT or Rac2–/– cells (both CD45.2 ) into nonablated WT (CD45.1 ) recipient animals. (A): The data show percentage of WT donor-derived (CD45.1 ) cells in the peripheral blood in the first 4 months post-transplant for a representative experiment (n = 8–10 animals per group). Lineage analysis includes granulocytes (Gr-1 ; white bars), B-lymphocytes (CD45R/B220 ; black bars), and T cells (CD3 ;striped bars). Cells not characterized by the antibodies used are indicated as stippled bars (*p # R( b) V* X) E- D) y; o1 e
3 T6 R( y/ U S) E" ], C6 `( jWhile the contribution of WT donor cells was multilineage in nonablated Rac2–/– recipients, WT chimerism was highest in the spleen and in lymph nodes. These data are consistent with the previously described defect in recirculating B-cell populations in Rac2–/– mice, which includes a pronounced deficiency of splenic marginal zone B cells . We further analyzed the presence of WT donor B cells in the spleen of reconstituted, nonablated recipient mice. A significantly higher percentage of WT donor-derived marginal zone B cells (CD21high, CD23low) were present in the spleens of Rac2–/– recipients in comparison with WT recipients (24.6% ± 6.5% vs. 16.7% ± 7.1%, p
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The evidence of a defect in Rac2–/– mice at the level of the stem cell is further supported by experiments that study engraftment of Rac2–/– hematopoietic cells (CD45.2 ) in nonablated congenic WT-recipient mice. In these experiments, Rac2–/– cells show significantly lower engraftment, than WT cells, as measured by contribution of donor-derived cells to the peripheral blood (Fig. 1D) over a 4-month period. This defect was not the result of a difference of HSC/P content in the transplant, as lineage–, c-Kit (LK) and lineage–, Sca-1 , c-Kit (LSK) frequencies in the harvested bone marrow of untreated WT and Rac2–/– animals do not show statistically significant differences (data not shown). The ~two-fold reduction in engraftment is observed at both early and late time points post-transplant. The donor cell contribution from both genotypes is multilineage, providing evidence that the engraftment is the result of donor-derived HSC. Furthermore, the lower engraftment capability of Rac2–/– HSC is not only reflected in the peripheral blood but is also seen in all other hematopoietic tissues examined (Fig. 1E).
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( T8 n5 q+ N9 q8 I( rAs demonstrated above, donor-derived WT cells engrafted in nonablated Rac2–/– recipients are capable of producing multilineage mature progeny over a period of 4 months after transplantation. To confirm a defect in the stem cell compartment in these mice, we transplanted whole bone marrow cells from nonablated primary WT and Rac2–/– recipients into lethally irradiated WT secondary recipient animals. As seen in Figure 2A, the donor-derived WT cells that preferentially engrafted in Rac2–/– (KO) mice reconstituted multilineage hematopoiesis (consisting of granulocytes, B cells, and T lymphocytes) for up to 4 months in the secondary recipients. In addition, donor-derived WT cells were present in the bone marrow, lymph nodes, and spleens of these secondary recipients when examined at 4 months after transplant (Fig. 2B). As expected, due to the low level of donor-derived engraftment in the BM of nonablated primary WT recipients, the mice transplanted with these bone marrow cells showed an overall low level of donor-derived WT cells in all hematopoietic tissues tested, never exceeding 0.5%. In contrast, WT donor-derived cells from primary Rac2–/– recipients averaged ~3% in the peripheral blood, equaling an approximately sixfold higher engraftment. The level of WT donor-derived cells from primary Rac2–/– recipients in different tissues of secondary transplanted mice 4 months after transplant resembled the distribution in primary animals, with the highest chimerism seen in the spleen followed by lymph nodes, peripheral blood, and bone marrow.
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Figure 2. Secondary transplantation of WT or Rac2–/– (KO); nonablated primary recipients engrafted with WT LDBM cells. (A): The data show the percentage of WT cells derived from the primary recipients (CD45.1 ) in the peripheral blood of secondary recipients over a period of 4 months postsecondary transplantation. Given are the mean overall percentage (height of the bar) of WT donor cells and the relative percentage of lineage marker positive cells (shaded areas). Lineage analysis includes granulocytes (Gr-1 ; white), B-lymphocytes (CD45R/B220 ; black), and T cells (CD3 ; striped). Cells not characterized by the antibodies used are indicated as stippled bars (*p & z, Y& @: F3 f* m6 \9 N7 |+ ~* A9 j
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Defective Long-Term Reconstitution in Competitive Repopulation Assays Despite Normal Homing
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% h H/ k ?/ K) p$ @) u' Z& p# BThese data demonstrate that Rac2–/– stem cells have an engraftment defect compared with WT stem cells. To measure this defect precisely, we performed competitive repopulation assays. Mixtures of congenic WT (CD45.1 ) and Rac2–/– (CD45.2 ) low-density bone marrow cells were infused at ratios of 3:1, 1:1, and 1:3 into lethally irradiated WT recipient animals. As shown in Figure 3A, at all ratios of infused cells, WT stem cells had a significant repopulation advantage over Rac2–/– stem cells, demonstrated by an increased ratio of WT:Rac2–/– cells in the peripheral blood over 4 months after transplant. At 4 months after transplant, the contribution of WT cells was increased ~threefold (range: 2.58 to 3.06) over Rac2–/– cells for each mixture of starting cells (to 9.17:1, 2.8:1, and 0.85:1 from 3:1, 1:1, and 1:3, respectively, p
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' P% z5 g W" ?2 h% Q' [Figure 3. Competitive repopulation capacity of WT and Rac2–/– KO low-density LDBM cells. (A): Time course of chimerism in the peripheral blood after transplantation of WT (CD45.1 ) and Rac2–/– (CD45.2 ) cells. Data are plotted in comparison with pretransplant mixtures of each genotype at different ratios. Shown are the mean and standard deviation error bars. The asterisk indicates statistically significant differences of pre-transplant ratios versus the ratios at 4 months post-transplant with p
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2 ^3 @2 y1 B) H+ Q C$ C" KThe increased ratio of WT: Rac2–/– cells was seen in all lineages, consistent with the preferential engraftment of pluripotent WT cells (Fig. 3B). The number of WT cells was also higher than Rac2–/– (KO) cells in the bone marrow of the recipient mice at 4 months post-transplantation (Fig. 3C) where the ratio of WT vs. Rac2–/– cells in the three groups increased to 6.18:1, 2:1, and 0.4:1, representing an average engraftment advantage of WT cells of 1.8 (range: 1.33–2.06). At 4 months post-transplantation, WT cells represented up to 65% of bone marrow cells in mice infused with a 1:1 ratio of WT: Rac2–/– cells (n = 5, p
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Engraftment of HSC in vivo is a multistep process that depends initially on appropriate homing of infused cells to the bone marrow medullary cavity and adhesion in the hematopoietic microenvironment, specifically in the stem cell niche. Since Rac2–/– cells showed defective adhesion to fibronectin (FN) in vitro, and Rac2–/– neutrophils demonstrate defects in endothelial capture and rolling , we compared the homing capacity of WT and Rac2–/– cells in vivo. Lethally irradiated recipients were transplanted with WT or Rac2–/– LDBM cells stained with the carboxyfluorescein succinimidyl ester (CFSE) dye. Surprisingly, as seen in Figure 4, there was no significant difference in the percentage of labeled WT versus Rac2–/– (KO) donor cells in the bone marrow 24 hours post-transplantation. In addition, no differences were detected specifically in the homing of the more primitive Sca-1 (Fig. 4) or c-Kit (data not shown) cells to the bone marrow. These data suggest that Rac2-deficient cells home normally to the bone marrow cavity compared with WT cells, as measured by the currently used "homing" assay.
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5 u: g7 ?4 v, u p% R: XFigure 4. Homing of WT and Rac2–/– (KO) low-density LDBM cells to the bone marrow cavity. Recovery of diacetate CFSE (light dotted bars) and CFSE , Sca-1 (dark dotted bars) cells from the hind limbs of lethally irradiated recipients 24 hours after infusion of 4 x 106 CFSE-labeled WT or Rac2–/–LDBM cells. The data show the means ± SD of one representative experiment (n = 8 per group) out of four independent experiments with similar results. Abbreviations: CFSE, carboxyfluorescein succinmidyl ester; KO, Knockout; LDBM, Low-density mononuclear bone marrow; WT, wild-type.7 s; u5 K0 n2 D6 v
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Differential Growth Abnormalities in Stromal-Independent Cultures Associated with Defective Adhesion to the Hematopoietic Microenvironment& r, u3 I- p. Y0 h6 ]. A* K
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Since Rac2–/– cells appeared to home normally to the medullary cavity of the bone marrow, we next determined if increased engraftment of WT cells in nonablated Rac2–/– mice and defects in competitive engraftment of Rac2–/– bone marrow cells was due to reduced intrinsic proliferation of primitive Rac2–/– hematopoietic cells. The growth of high proliferative potential colony-forming cells (HPP-CFCs), a measure of the number and proliferation of primitive hematopoietic stem and progenitor cells, from purified LSK bone marrow cells of Rac2–/– and WT mice was examined in response to SCF, GM-CSF, IL-1, and IL-3 in double-layer soft agar assays. As seen in Figure 5A, the growth of HPP-CFCs was equivalent for Rac2–/– (KO) and WT bone marrow cells.
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/ \4 B$ i. Q! m" |+ {$ |Figure 5. Growth of primitive WT and Rac2–/– (KO) hematopoietic cells in vitro. (A): Growth of HPP (white bars) and LPP (black bars) CFCs from WT and Rac2–/– lineage–, Sca-1 , c-Kit (LSK) cells, in response to SCF, GM-CSF, IL-3, and IL-1, is shown. The bars represent the frequency of CFC/300 plated in a double-layer agar assay. Data represent mean ± SD (n = 3). (B) and (C): Frequency of CAFCs in lineage–, c-Kit (LK) and LDBM cells from WT and Rac2–/– mice. Figure 5C shares the same y-axis label as Figure 5B. The frequency of CAFCs per 1 x 105 LK cells of WT (black bars) and Rac2–/– (white bars) from FACS-purified (B) LK cells or (C) LDBM was measured in a limiting dilution assay. Cells were plated on confluent monolayers of the FBMD-1 cell line in 96-well cluster plates. Displayed is the mean frequency (± standard error of the mean) of CAFCs at culture days 28, 35, and 42, calculated using Poisson statistics. Data are shown on a logarithmic scale. The figure shows data from one of two independent experiments with similar results (*p x0 u$ P. y/ M
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In contrast, the frequency of HSC/P measured in the stromal-dependent, limiting dilution CAFC assays, which requires coordinated adhesion and migration of HSC/P under a layer of supporting stromal cells, was consistently abnormal in Rac2–/– mice. As seen in Figure 5B, Rac2–/– LK cells (white bars) showed a 2.7- to 3.1-fold decrease in the frequency of d28, d35, and d42 CAFCs compared with WT cells (black bars). A similar reduction in the frequency of CAFCs was present in Rac2–/– LDBM cells (Fig. 5C). This defect is intrinsic to the Rac2–/– HSC as WT stromal cells do not express Rac2, as determined by reverse transcription polymerase chain reaction (data not shown).6 Z. L' d( K$ o2 W+ W8 \% L
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However, when analyzing cell cycle status of LK cells that successfully adhered to FBMD-1 cells after 24 and 48 hours of coculture, there was no significant difference between WT and Rac2–/– cells in the percentage of cells in different stages of the cell cycle (Table 1). These data, together with the growth of cells in HPP-CFC assays, suggests that there is no defect in the intrinsic proliferative capacity in Rac2–/– HSC/P but implicate defective stromal interactions of Rac2–/– HSC/P. Furthermore, the ability of Rac2–/– bone marrow to establish robust long-term marrow (Dexter) cultures was significantly reduced, even in the presence of WT stromal cells. In contrast, stromal cells from Rac2–/– animals were capable of supporting long-term marrow cultures initiated with WT hematopoietic cells (data not shown).- F$ g7 v( K2 W6 U" C
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Table 1. Cell cycle analysis of bone marrow cells (percentage) cultured on confluent femur bone marrow density 1 (FBMD-1)' k$ i$ o: ^4 ?6 e
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Taken together, the normal growth of Rac2–/– HPP-CFCs compared with WT bone marrow but reduced growth of immature hematopoietic cells in CAFC assays and long-term cultures suggests defective interactions with the hematopoietic microenvironment. To directly measure this interaction, we next determined the adhesion of Rac2–/–hematopoietic cells to bone marrow–derived stromal cells in vitro. Rac2–/– LDBM cells and more purified LK cells showed 2.1- and 8.7-fold reduction (LDBM: Rac2–/– 9.3% ± 2.5% vs. WT 19.7% ± 5.6%; LK: Rac2–/– 7.9% ± 1.8% vs. WT 68.9% ± 5.7%) in adhesion to stromal cells, respectively, compared with WT cells (p
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DISCUSSION; p+ x1 B1 W+ v, ]) C }
- ~# o, G+ a& eWe thank Jamie Siefring, Aparna Jasti, and Victoria Summey-Harner for technical support. We are also grateful to the members of the laboratory for helpful discussion and to Keisha Steward and Eva Meunier for administrative assistance. This work was supported by National Institutes of Health grant
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# Z, t) H2 N9 Y1 a5 p4 |REFERENCES9 x. `5 [# [- ]( H+ e& W+ j) P
, x% W1 t& w. i! ~
Lord BI, Testa AG, Hendry JH. The relative spatial distributions of CFUs and CFUs in the normal mouse femur. Blood 1975;46:65–72.
. O# Y; {: O) B% W/ s! e2 ~9 _. A
+ ?! t: f5 C3 f: ~" b" S" }Rosendaal M, Adam J. Haemopoietic progenitors in different parts of one femur perform different functions during regeneration. Blood Cells 1987;12:629–646.
1 k7 d4 H9 v8 g; v
& Z' B6 _& X! D6 |6 c1 j& JUchida N, Fleming WH, Alpern EJ et al. Heterogeneity of hematopoietic stem cells. Curr Opin Immunol 1993;5:177–184.
& J) _% T( p. X# b/ q
9 y1 P) @( i! u0 m, ^Coulombel L, Auffray I, Gaugler MH et al. Expression and function of integrins on hematopoietic progenitor cells. Acta Haematol 1997;97:13–21.2 T& v+ K9 o# g/ u" O; X% Z
$ K3 g0 @. t- oGallagher JJ, Spooncer EP, Dexter TM. Role of the cellular matrix in haemopoiesis. I. Synthesis of glycosaminoglycan by mouse bone marrow cell cultures. J Cell Sci 1983;632:1565–1571.
/ u! }3 i8 A3 v) Z3 {7 ~
# H w5 L8 w7 h) I3 U+ yCalvi LM, Adams GB, Weibrecht KW et al. Osteoblastic cells regulate the haematopoietic stem cell niche. Nature 2003;425:841–846.2 s0 |/ }* u) v* c! j) L8 s
! m! \1 P- ]! y! M
Moore MA. Cytokine and chemokine networks influencing stem cell proliferation, differentiation, and marrow homing. J Cell Biochem Suppl 2002;38:29–38.
! X' c& n# c* L2 y0 F! p% r5 a6 M" [$ q8 ?) a K
Srour EF, Jetmore A, Wolber FM et al. Homing, cell cycle kinetics and fate of transplanted hematopoietic stem cells. Leukemia 2001;15:1681–1684.
* c B) ]" ~/ q& j, V) `
. N4 Q' }9 q" L% {$ f0 ]& M0 UQuesenberry PJ, Stewart FM, Becker P et al. Stem cell engraftment strategies. Ann N Y Acad Sci 2001;938:54–61; discussion 2., ]9 Q) i: w3 z3 Z* d8 N" ^
) g* C- ~7 B4 C& ^1 N# b% {Bingaman AW, Waitze SY, Alexander DZ et al. Transplantation of the bone marrow microenvironment leads to hematopoietic chimerism without cytoreductive conditioning. Transplantation 2000;69:2491–2496.) E# x" W" _# h% S% F
" N8 ]8 y# E* S GTorok-Storb B, Holmberg L. Role of marrow microenvironment in engraftment and maintenance of allogeneic hematopoietic stem cells. Bone Marrow Transplant 1994;14(Suppl 4):S71–73.
2 c' h7 ?9 S9 B, ?5 K' U$ b. k
, {" g R* _+ K- q( ]Friel J, Heberlein C, Itoh K et al. Role of the stem cell factor (SCF) receptor and the alternative forms of its ligand (SCF) in the induction of long-term growth by stroma cells. Leukemia 1997;11(Suppl 3):493–495.
u! l$ }# x: P+ w0 @) ~1 X0 N, g' U( s
Friel J, Itoh K, Bergholz U et al. Hierarchy of stroma-derived factors in supporting growth of stroma-dependent hemopoietic cells: membrane-bound SCF is sufficient to confer stroma competence to epithelial cells. Growth Factors 2002;20:35–51. V* b9 \7 X8 I3 L
, Q1 p( b2 k* H/ v" y" H
Slanicka Krieger M, Nissen C, Manz CY et al. The membrane-bound isoform of stem cell factor synergizes with soluble flt3 ligand in supporting early hematopoietic cells in long-term cultures of normal and aplastic anemia bone marrow. Exp Hematol 1998;26:365–373.
$ x, h# ^2 [0 _ H$ v
+ s1 h+ u1 P- }0 LBruno E, Luikart SD, Long MW et al. Marrow-derived heparan sulfate proteoglycan mediates the adhesion of hematopoietic progenitor cells to cytokines. Exp Hematol 1995;23:1212–1217.( k. q, K6 f. D+ n8 ~
: O+ p/ v! ^' m; n
Roberts R, Gallagher J, Spooncer E et al. Heparin sulphate bound growth factors: a mechanism for stromal cell mediated haemopoiesis. Nature 1988;332:376–378.2 R+ B5 M( L. `- b: ` Q) T
6 m9 E* U( } ]$ C1 y
Peled A, Kollet O, Ponomaryov T et al. The chemokine SDF-1 activates the integrins LFA-1, VLA-4, and VLA-5 on immature human CD34 cells: role in transendothelial/stromal migration and engraftment of NOD/SCID mice. Blood 2000;95:3289–3296.: w6 ?& C- C- W" ?! t
& @8 p2 X$ e V7 {9 q0 m4 [
Plett PA, Frankovitz SM, Wolber FM et al. Treatment of circulating CD34 cells with SDF-1 or anti-CXCR4 antibody enhances migration and NOD/SCID repopulating potential. Exp Hematol 2002;30:1061–1069.) K! s% Z- `6 p# X
$ ~( j; x' l; j0 A/ vTan BL, Yazicioglu MN, Ingram D et al. Genetic evidence for convergence of c-Kit and 4 integrin-mediated signals on class IA PI-3 kinase and Rac pathway in regulating integrin directed migration in mast cells. Blood 2003;101:4725–4732.- y* M7 V: o: t/ ~' q
( x9 N$ {2 w# p2 [' f- ?: Z2 w) {8 l6 H
Wagner N, Muller W. Functions of alpha 4-and beta 7-integrins in hematopoiesis, lymphocyte trafficking and organ development. Curr Top Microbiol Immunol 1998;231:23–32.- ]* t; ?. X9 d" i& v: X
; G$ x1 g4 V4 p8 W tHemler ME, Lobb RR. The leukocyte beta 1 integrins. Curr Opin Hematol 1995;2:61–67.4 @" B l0 j2 o
( b0 m* I" l% k, {
Berrios VM, Dooner GJ, Nowakowski G et al. The molecular basis for the cytokine-induced defect in homing and engraftment of hematopoietic stem cells. Exp Hematol 2001;29:1326–1335.
0 } }1 d# L0 |4 e. S
7 Z3 _' ?; D2 N* FVerfaillie CM, Benis A, Iida J et al. Adhesion of committed human hematopoietic progenitors to synthetic peptides from the C-terminal heparin-binding domain of fibronectin: cooperation between the integrin a4 b1 and the CD44 adhesion receptor. Blood 1994;84:1802–1811.
/ q' R2 c2 K' i* n
! ?; m1 U0 A# I$ k9 k0 ~- uOostendorp RA, Reisbach G, Spitzer E et al. VLA-4 and VCAM-1 are the principal adhesion molecules involved in the interaction between blast colony-forming cells and bone marrow stromal cells. Br J Haematol 1995;91:275–284.. h: z' H0 r' X; v4 a7 K- ^1 Y
4 }+ v9 e1 s! r0 F6 F# l
Roy V, Verfaillie CM. Expression and function of cell adhesion molecules on fetal liver, cord blood and bone marrow hematopoietic progenitors: implications for anatomical localization and developmental stage specific regulation of hematopoiesis. Exp Hematol 1999;27:302–312.
! x: s5 [: M; f) ^6 Q+ ?& ?9 c: V7 L# h. E* g% @+ |2 z
Williams DA, Rios M, Stephens C,. Fibronectin and VLA-4 in haematopoietic stem cell-microenvironment interactions. Nature 1991;352:438–441. B8 V6 {4 R# x; b1 a( S
. t. k1 u5 A$ _4 V" [4 [0 a+ F
van der Loo JC, Xiao X, McMillin D et al. VLA-5 is expressed by mouse and human long-term repopulating hematopoietic cells and mediates adhesion to extracellular matrix protein fibronectin. J Clin Invest 1998;102:1051–1061.
" B0 q- m3 H3 F+ H+ a2 T
! N& h7 N" G7 A/ m7 p& |' h; hPapayannopoulou T, Craddock C, Nakamoto B et al. The VLA4/VCAM-1 adhesion pathway defines contrasting mechanisms of lodgement of transplanted murine hemopoietic progenitors between bone marrow and spleen. Proc Natl Acad Sci U S A 1995;92:9647–9651.
# u5 ^- Y+ B8 i9 [0 C) d0 F. b( a
Papayannopoulou T, Priestley GV, Nakamoto B et al. Molecular pathways in bone marrow homing: dominant role of 4 ?1 over ?2-integrins and selectins. Blood 2001;98:2403–2411.
3 I% l1 ^+ R0 P; r, L
! H1 Y6 S3 Q6 B; Y. H- D5 C9 j6 tWiesmann A, Spangrude GJ. Marrow engraftment of hematopoietic stem and progenitor cells is independent of Gi-coupled chemokine receptors. Exp Hematol 1999;27:946–955., o2 F, r& }$ c0 ] c2 t
d/ q' c" X# l. a
Frenette PS, Wagner DD. Adhesion molecules〞Part 1. N Engl J Med 1996;334:1526–1529.
( ^2 Q3 k6 Y/ e u3 K5 [6 h
3 o, q; G3 h9 g/ a, z6 y! G# GFrenette PS, Wagner DD. Adhesion molecules_Part 2. Blood vessels and blood cells. N Engl J Med 1996;335:43–45.
( S2 a! K; E; @! M
9 a ]: P. `. a- ~( E7 J$ TNetelenbos T, Zuijderduijn S, Van Den Born J et al. Proteoglycans guide SDF-1-induced migration of hematopoietic progenitor cells. J Leukoc Biol 2002;72:353–362.
6 E8 u/ t; o! x1 w; _3 X" O: J
/ D4 V) y' x) b0 `% A6 wPilarski LM, Pruski E, Wizniak J et al. Potential role for hyaluronan and the hyaluronan receptor RHAMM in mobilization and trafficking of hematopoietic progenitor cells. Blood 1999;93:2918–2927.
- W {1 K5 O& D6 ~% s, B4 H
- [% |# g( _7 H1 Z e) OMicklem HS, Clarke CM, Evans EP et al. Fate of chromosome-marked mouse bone marrow cells tranfused into normal syngeneic recipients. Transplantation 1968;6:299–302.
1 H; q0 e' i* N) y
, _/ w3 Q/ N8 v6 xSchofield R. The relationship between the spleen colony-forming cell and the haemopoietic stem cell: a hypothesis. Blood Cells 1978;4:7–25.
4 d) ?$ g7 n8 Z. Y3 Q# [# z3 L/ q
2 N( q0 a1 L6 L8 ^$ H; l; o c* |7 DTakada Y, Takada A. Proliferation of donor hematopoietic cells in irradiated and unirradiated host mice. Transplantation 1971;12:334–338., I, C) Y0 Q8 J; x; Y0 r
" m& g( _8 h6 |1 q% U. xTabbara IA, Robinson BE. Hematopoietic growth factors. Anticancer Res 1991;11:81–90.
$ ]3 @7 D" b/ k3 h4 Y$ o) N
) }; x+ |. A: I- H# ~Saito M. Recent trends in research on differentiation of hematopoietic cells and lymphokines (hemopoietins). Hum Cell 1992;5:54–69.# o, W& \8 h8 u ^- D/ h+ R1 E# P8 V
+ v3 [' R# v" i+ PSimmons PJ, Levesque JP, Haylock DN. Mucin-like molecules as modulators of the survival and proliferation of primitive hematopoietic cells. Ann N Y Acad Sci 2001;938:196–206; discussion 7.8 ?/ a& S; W. ^
E; m( F8 A% a* l! I9 R0 p
Rafii S, Mohle R, Shapiro F et al. Regulation of hematopoiesis by microvascular endothelium. Leuk Lymphoma 1997;27:375–386.
" a. s9 i. f) W7 d n% T/ |% j c" n$ F3 Q5 T! h/ W7 t) q1 S- K
Croker BA, Handman E, Hayball JD et al. Rac2-deficient mice display perturbed T-cell distribution and chemotaxis, but only minor abnormalities in T(H)1 responses. Immunol Cell Biol 2002;80:231–240.
5 g% C) s5 B. _/ t f6 ?( s& {% y' v
Croker BA, Tarlinton DM, Cluse LA et al. The Rac2 guanosine triphosphatase regulates B lymphocyte antigen receptor responses and chemotaxis and is required for establishment of B-1a and marginal zone B lymphocytes. J Immunol 2002;168:3376–3386. e, A2 _! |6 d8 C7 O+ }
0 ~8 ?0 |2 Q8 Y5 Q. J: c6 l9 W7 ^( V
Hall AJ, Haar JL, McCormick KR et al. Conditioning of Nude bone marrow increases in vitro migration to thymus supernatant. Thymus 1992;20:227–238.6 }& W3 ~! J2 H2 t& F' g) l6 _% {
" N: c8 h0 G" O! v1 ^
Etienne-Manneville S, Hall A. Integrin-mediated activation of Cdc42 controls cell polarity in migrating astrocytes through PKC. Cell 2001;106:489–498.6 T3 G& o9 R' ^$ Q! B) O! s- @& `+ S
2 R* @" c x- HSymons M. Adhesion signaling: PAK meets Rac on solid ground. Curr Biol 2000;10:R535–537.
$ M5 ^ ?% q0 B4 o+ y" n
8 [2 A" x& U; i* FNarumiya S, Ishizaki T, Watanabe N. Rho effectors and reorganization of actin cytoskeleton. FEBS Lett 1997;410:68–72.8 t W- N+ d" a; x/ I, j! y4 D
e7 |: e! J$ F7 y" \Williams DA, Tao W, Yang FC et al. Dominant negative mutation of the hematopoietic-specific RhoGTPase, Rac 2, is associated with a human phagocyte immunodeficiency. Blood 2000;96:1646–1654.
+ h* G* b; S# h+ E: [" @5 D8 | X1 F8 e7 @! P. ~0 A/ ~6 }
Kapur R, Cooper R, Zhang L et al. Cross-talk between 4?1/5?1 and c-Kit results in opposing effect on growth and survival of hematopoietic cells via the activation of focal adhesion kinase, mitogen-activated protein kinase, and Akt signaling pathways. Blood 2001;97:1975–1981." Z/ u7 R5 y" p" D7 _
& S; v! [: J( {' x1 ]: G5 Q0 u
Yang FC, Kapur R, King AJ et al. Rac 2 stimulates Akt activation affecting BAD/Bcl-XL expression while mediating survival and actin-based cell functions in primary mast cells. Immunity 2000;12:557–568.+ Q K0 z* E1 c {
3 S$ p. f. j$ L B W, b: w8 UYang FC, Atkinson SJ, Gu Y et al. Rac and Cdc42 GTPases control hematopoietic stem cell shape, adhesion, migration, and mobilization. Proc Natl Acad Sci U S A 2001;98:5614–5618./ u' p0 p, Q$ X2 L4 ?) ~7 E- O
y' f" A% M- V8 a; S% jRoberts AW, Kim C, Zhen L et al. Deficiency of the hematopoietic cell-specific Rho family GTPase Rac2 is characterized by abnormalities in neutrophil function and host defense. Immunity 1999;10:183–196.
/ q4 q! @& K1 F: T p. X
: }+ w, g( }% I, y g( B* y4 P% nLaudanna C, Campbell JJ, Butcher EC. Role of Rho in chemoattractant-activated leukocyte adhesion through integrins. Science 1996;271:981–983.7 R' P9 y7 ?1 e/ ~- ]$ j+ D
8 h5 A! g( u5 Y4 f
Zigmond SH. Signal transduction and actin filament organization. Curr Opin Cell Biol 1996;8:66–73.
3 x- `( d$ r& B3 S6 H* ^! p% R8 N! E
Tapon N, Hall A. Rho, Rac and Cdc42 GTPases regulate the organization of the actin cytoskeleton. Curr Opin Cell Biol 1997;9:86–92.0 ?7 {) k, x1 w, l- X" l6 K9 @, h! q5 x
/ O6 H% u) U7 G9 D Y$ |0 LBengtsson T, Sarndahl E, Stendahl O et al. Involvement of GTP-binding proteins in actin polymerization in human neutrophils. Proc Natl Acad Sci U S A 1990;87:2921–2925.
* r7 V. y0 E- X i/ D) Z: M. _/ t( C! ^, [2 U9 o" I
Didsbury J, Weber RF, Bokosh GM et al. Rac, a novel ras-related family of proteins that are botulinum toxin substrates. J Biol Chem 1989;264:16378–16382.: h: Q9 h& j* k% G
: f0 q3 T- x0 P0 X0 a
Shirsat NV, Pignolo RJ, Kreider BL et al. A member of the ras gene superfamily is expressed specifically in T, B and myeloid hemopoietic cells. Oncogene 1990;5:769–772.0 ]5 A* M3 m$ W7 c3 @3 z
4 S( \, s. z8 {, u H& @6 _; t
Moll J, Sansig G, Fattori E et al. The murine rac1 gene: cDNA cloning, tissue distribution and regulated expression of rac1 mRNA by disassembly of actin microfilaments. Oncogene 1991;6:863–866.
$ R0 w' v5 R8 Z
/ I, b; w, P# X& ^% M1 WHaataja L, Groffen J, Heisterkamp N. Characterization of RAC3, a novel member of the Rho family. J Biol Chem 1997;272:20384–20388.
8 H; D# o& }; @/ t! j: p( d' x
0 Y9 a9 m2 }3 J( O$ y& NGu Y, Williams DA. RAC2 GTPase deficiency and myeloid cell dysfunction in human and mouse. J Pediatr Hematol Oncol 2002;24:791–794.
" w9 C) X2 K/ b
1 {7 n7 U0 a' M6 V7 EGu Y, Jia B, Yang FC et al. Biochemical and biological characterization of a human Rac2 GTPase mutant associated with phagocytic immunodeficiency. J Biol Chem 2001;276:15929–15938.
/ U5 k% F5 P0 c5 ^! }: ^ G
, d# n( `7 Z0 C6 G3 e; GGu Y, Filippi MD, Cancelas JA et al. Hematopoietic cell regulation by Rac1 and Rac2 guanosine triphosphatases. Science 2003;302:445–449.
- V" F* f& z Z+ q
F" k! r' P5 ~2 _Breems DA, Blokland EA, Neben S et al. Frequency analysis of human primitive haematopoietic stem cell subsets using a cobblestone area forming cell assay. Leukemia 1994;8:1095–1104.( v" M. X$ e" c% \3 ]7 }
4 t1 V& O# }& r+ u
Quesenberry PJ, Ramshaw H, Crittenden RB et al. Engraftment of normal murine marrow into nonmyeloablated host mice. Blood Cells 1994;20:348–350. ^) e# W: J1 R. d! P, F$ _* ?
! r6 e: S( V) f9 |7 P
Clapp DW, Freie B, Srour E et al. Myeloproliferative sarcoma virus directed expression of beta-galactosidase following retroviral transduction of murine hematopoietic cells. J Exp Hematol 1995;23:630–638.
6 o' b. Q* I8 q; ^* N) D6 t Y; S
Harrison DE, Stone M, Astle CM. Effects of transplantation on the primitive immunohematopoietic stem cell. J Exp Med 1990;172:431–437.
6 R* u- O; r/ O J- v& b& s9 ^4 O1 Z6 K/ I, T1 w* W7 O
Ploemacher RE, van der Sluijs JP, Voerman JS et al. An in vitro limiting-dilution assay of long-term repopulating hematopoietic stem cells in the mouse. Blood 1989;74:2755–2763.
# T" n8 H. [# K ^
& a% u g& }% U1 K, G2 |Bradley TR, Hodgson GS. Detection of primitive macrophage progenitor cells in mouse bone marrow. Blood 1979;54:1446–1450.) U. H! r, G7 R; ], D& N/ {9 b
. ]- `- f& j' l! @ q! p4 tGu Y, Byrne MC, Paranavitana NC et al. Rac2, a hematopoiesis-specific Rho GTPase, specifically regulates mast cell protease gene expression in bone marrow-derived mast cells. Mol Cell Biol 2002;22:7645–7657.. V0 s$ T* _8 g+ }) w
& A# a( D: s6 m3 ~Levesque JP, Takamatsu Y, Nilsson SK et al. Vascular cell adhesion molecule-1 (CD106) is cleaved by neutrophil pro-teases in the bone marrow following hematopoietic progenitor cell mobilization by granulocyte colony-stimulating factor. Blood 2001;98:1289–1297.
: F* u! Q; r, x0 M" G* ~# x Q* {& z6 I5 T' X" r O
Allen WE, Jones GE, Pollard JW et al. Rho, Rac and Cdc42 regulate actin organization and cell adhesion in macrophages. J Cell Sci 1997;110:707–720.
4 @* F, w. j& _% w" ~4 x8 r8 L* [* j- @% F4 q9 |! p: {
D’Souza-Schorey C, Boettner B, Van Aelst L. Rac regulates integrin-mediated spreading and increased adhesion of T lymphocytes. Mol Cell Biol 1998;18:3936–3946.* p2 }, M" z4 {5 ]7 K
6 h6 p) I" u V: k) LCraddock CF, Nakamoto B, Andrews RG et al. Antibodies to VLA4 integrin mobilize long-term repopulating cells and augment cytokine-induced mobilization in primates and mice. Blood 1997;90:4779–4788.. I d- ~( n- ?+ K1 {. {9 r S- L9 x
# f3 E o% c5 ? o* K* ?
Papayannopoulou T, Nakamoto B. Peripheralization of hemopoietic progenitors in primates treated with anti-VLA4 integrin. Proc Natl Acad Sci U S A 1993;90:9374–9378.( e8 g- C9 j+ i" R& }0 n5 s2 s$ q
; M3 }( }* D/ F: n8 dVermeulen M, Le Pesteur F, Gagnerault MC et al. Role of adhesion molecules in the homing and mobilization of murine hematopoietic stem and progenitor cells. Blood 1998;92:894–900." @) K: ~3 t! \3 O9 L6 q. y
6 h: w z" \- U4 u. h+ n! W0 t2 {Scott LM, Priestley GV, Papayannopoulou T. Deletion of alpha4 integrins from adult hematopoietic cells reveals roles in homeostasis, regeneration, and homing. Mol Cell Biol 2003;23:9349–9360.(Michael Jansena, Feng-Chu) |
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