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1.
OBJECTIVE: Busulfan (BU) is often used in conditioning regimens prior to bone marrow transplantation, but its mechanism of action remains to be resolved. We have examined the possibility that BU may exert part of its toxic effects via DNA alkylation at the O6 position of guanine as this might provide an approach to improving the conditioning regimen. METHODS: Survival of LAMA-84 and RJKO cells was assessed by colony-forming assay and cell counting, respectively. O6-alkylguanine-DNA alkyltransferase (ATase) activity was assayed by transfer of radioactivity from [3H]-methylated DNA. Colony-forming potential of normal human bone marrow cells (BMC) was measured in the presence of appropriate growth factors as the formation of both granulocyte-macrophage colony-forming units (CFU-GM) or burst-forming unit erythroids (BFU-E) within the same assay. Murine hematopoietic precursors were grown under a bone marrow stromal cell line to allow measurement of the frequency of cobblestone area-forming cells (CAFC) that correspond to CFU-GM, spleen colony-forming units (CFU-S), and the primitive stem cells with long-term repopulating ability. RESULTS: Inactivation of ATase by O6-benzylguanine (O6-BeG) sensitized a human erythromegakaryocytic cell line (LAMA-84) and normal human bone marrow progenitors to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) but not to BU toxicity. BCNU, but not BU, inactivated ATase in LAMA-84 cells. Overexpression of human ATase in cDNA transfected Chinese hamster cells attenuated the toxicity of BCNU but not BU. Finally, the in vivo treatment of mice showed that the depletion of primitive stem cells by BU as measured in the CAFC assay was not affected by addition of O6-BeG. O6-BeG did, however, dramatically potentiate BCNU toxicity in all CAFC subsets, leading to depletion of more than 99% stem cells. CONCLUSION: These data suggest that BU does not elicit toxicity via alkylation at the O6 position of guanine in DNA in a way that can be influenced by ATase modulation.  相似文献   

2.
M G Kruger  R L Riley  E A Riley  J M Elia 《Blood》1990,76(2):383-392
Murine Ly1+ pre-B cell lines, including 70Z/3 and three pre-B cell lines derived from long-term bone marrow cultures, exhibited selective adherence to bone marrow stromal cells. In contrast, splenic B cells, the A20 B-cell lymphoma, and four Ly1- B cell lines derived from long-term bone marrow cultures failed to adhere substiantially to bone marrow cultures failed to adhere substiantially to bone marrow stroma. Ly1+ pre-B cell lines were induced to express kappa light chains by exposure to either lipopolysaccharide (LPS), recombinant interleukin-1 (IL-1), or stromal cells. However, induction of kappa light chains failed to prevent pre-B cell adherence to stromal cells. Supernatants derived from primary bone marrow stromal cells decreased Ly1 expression on the Ly1+ pre-B cell lines. These experiments suggest that (1) expression of immunoglobulin light chains by developing Ly1+ pre-B cells is mediated by bone marrow stromal cells; (2) loss of specific adherence to stroma is progressive and occurs post-light chain induction; and (3) soluble products of stromal cells may downregulate expression of surface Ly1 on otherwise Ly1+ pre-B cells. The importance of these observations to the development of both the Ly1- and Ly1+ B cell lineages in the mouse is discussed.  相似文献   

3.
Summary The production of granulocyte-macrophage colony-forming cells (GM-CFC) and the proliferation period in human long-term bone marrow cultures are inferior to murine cultures. There is also evidence that recharge of the cultures after establishing confluent stromal layers will not greatly improve myelopoiesis. Data in the literature indicate that PHA-responsive T lymphocytes persist for up to 5 weeks in human but not in murine long-term marrow cultures. We therefore analyzed the effects of recharging micro long-term bone marrow cultures with bone marrow cell samples depleted by T lymphocytes. Depletion was performed in a complement-mediated cytotoxicity assay by applying the monoclonal antibody CAMPATH-1. Our data show that regardless of whether T cells were removed only at recharge, at both initiation and recharge, or only at initiation, obvious enhancement could neither be achieved in the GM-CFC production nor in the proliferation period. Furthermore, no advantage was seen when using syngeneic marrow cells. We conclude that in allogeneic long-term marrow cultures hemopoiesis is not limited by immunological incompatibilities.  相似文献   

4.
Porter  CD; Parkar  MH; Collins  MK; Levinsky  RJ; Kinnon  C 《Blood》1996,87(9):3722-3730
The primary immunodeficiencies are attractive candidates for the development of gene therapy approaches based on the transduction of hematopoietic cells. We have constructed a high-titer recombinant retrovirus for expression of gp91-phox, deficiencies of which cause the X-linked form of chronic granulomatous disease (X-CGD). We have used this vector to transduce human bone marrow, using either unfractionated mononuclear cells or purified CD34+ cells as targets and evaluated several infection protocols. Efficient gene transfer to progenitors and long-term culture-initiating cells (LTC-IC) was obtained for each target population. Importantly for potential clinical application, this could be achieved without the use of exogenous cytokines or polybrene. Progenitors representing each of the lineages detectable in vitro were transduced at equal efficiencies. The vector was shown partially to restore gp91-phox deficiency and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in transduced cells derived from X- CGD patients. These data demonstrate that it is possible to transduce primitive human hematopoietic cells efficiently and reconstitute NADPH oxidase.  相似文献   

5.
The effects of several hematopoietic growth factors on primitive murine bone marrow progenitor cells [colony-forming unit(s)-spleen (CFU-S)] have been investigated during culture for 2-6 days. Interleukin 3 (IL-3) was required for CFU-S survival in culture, and the combination of IL-3 and interleukin 6 (IL-6) increased the number of CFU-S in culture 10-fold over the number obtained with IL-3 alone. Stem cell function was measured by competitive repopulation; IL-3 was required, and IL-3 and IL-6 appear to act synergistically to enhance stem cell recovery from these cultures. These data appear to be relevant for retroviral-mediated gene transfer into stem and progenitor cells. Murine bone marrow cells were infected with a retrovirus containing the human beta-globin gene in the presence of various growth factors. Only 2 of 17 mice reconstituted with cells infected in the presence of IL-3 alone showed long-term expression of the human beta-globin gene (12 months), as opposed to 6 of 11 mice reconstituted with cells infected in the presence of IL-3 and IL-6. Medium conditioned by 5637 bladder carcinoma cells, a source of several hematopoietic growth factors, increased the frequency of infection of CFU-S but did not enhance stem cell infection or the repopulating potential of cultured bone marrow cells. Stem cells containing the human beta-globin provirus from these animals were shown to be capable of reconstituting secondary recipients in which the human beta-globin gene was expressed.  相似文献   

6.
A recombinant retroviral vector (MFG-GC) was used to study the efficiency of transduction of the human gene encoding glucocerebrosidase (GC; D-glucosyl-N-acylsphingosine glucohydrolase, EC 3.2.1.45), in mouse hematopoietic stem cells and expression in their progeny. Transfer of the GC gene to CFU-S (spleen cell colony-forming units) in primary and secondary recipients was virtually 100%. In mice 4-7 months after transplantation, highly efficient transfer of the human gene to bone marrow cells capable of long-term reconstitution was confirmed by detection of one or two copies per mouse genome in hematopoietic tissues and in cultures of pure macrophages. Expression of the human gene exceeded endogenous activity by several fold in primary and secondary CFU-S, tissues from long-term reconstituted mice, and explanted macrophages cultures. These studies are evidence of the feasibility of efficient transfer of the GC gene to hematopoietic stem cells and expression in their progeny for many months after reconstitution. The results of this study strengthen the rationale for gene therapy as a treatment for Gaucher disease.  相似文献   

7.
8.
Laneuville  P; Chang  W; Kamel-Reid  S; Fauser  AA; Dick  JE 《Blood》1988,71(3):811-814
Retroviral vectors containing the selectable bacterial gene for G418 resistance (neo) were used to demonstrate gene transfer into primary human bone-marrow progenitor cells. To obtain populations of cells in which a high proportion of cells were expressing the neo gene, several important modifications were made to earlier procedures. Cells from normal donors were infected in vitro, were exposed to high concentrations of G418 for two days in liquid culture to enrich for cells expressing the neo gene, and were plated in semisolid medium. Gene transfer and expression were detected in colonies arising from progenitors of granulocyte-macrophage and erythroid lineages. Survival curves indicated that a high proportion of progenitor cells, approaching 100%, were G418 resistant. Furthermore, addition of growth factors contained in 5637-conditioned medium to the bone marrow improved the recovery of G418-resistant progenitors twofold to threefold. In addition to these biological measurements of gene expression in progenitor cells, significant levels of neo-specific RNA, similar to the levels of RNA expression in the virus-producing fibroblast cell line, were detected in the bone marrow cells after preselection. These results demonstrate that retrovirus vectors can be used successfully to transfer genes at high efficiency into progenitor cells in the human blood-forming system.  相似文献   

9.
Fabry disease is a lysosomal storage disorder that is due to a deficiency in alpha-galactosidase A (alpha-gal A). Previously we have shown that a recombinant retrovirus synthesized for the transfer of the human alpha-gal A coding sequence was able to engineer enzymatic correction of the hydrolase deficiency in fibroblasts and lymphoblasts from Fabry patients. The corrected cells secreted alpha-gal A that was taken up and utilized by uncorrected bystander cells, thus demonstrating metabolic cooperativity. In separate experiments we used transduced murine bone marrow cells and successfully tested and quantitated this phenomenon in vivo. In the present studies, which were designed to bring this therapeutic approach closer to clinical utility, we establish that cells originating from the bone marrow of numerous Fabry patients and normal volunteers can be effectively transduced and that these target cells demonstrate metabolic cooperativity. Both isolated CD34+-enriched cells and long-term bone marrow culture cells, including nonadherent hematopoietic cells and adherent stromal cells, were transduced. The transferred gene generates increased intracellular alpha-gal A enzyme activity in these cells. Further, it causes functional correction of lipid accumulation and provides for long-term alpha-gal A secretion. Collectively, these results indicate that a multifaceted gene transfer approach to bone marrow cells may be of therapeutic benefit for patients with Fabry disease.  相似文献   

10.
This study demonstrates that in vivo exposure to cigarette smoke (CS) and in vitro treatment of long-term bone marrow cultures (LTBMCs) with nicotine, a major constituent of CS, result in inhibition of hematopoiesis. Nicotine treatment significantly delayed the onset of hematopoietic foci and reduced their size. Furthermore, the number of long-term culture-initiating cells (LTC-ICs) within an adherent layer of LTBMCs was significantly reduced in cultures treated with nicotine. Although the production of nonadherent mature cells and their progenitors in nicotine-treated LTBMCs was inhibited, this treatment failed to influence the proliferation of committed hematopoietic progenitors when added into methylcellulose cultures. Bone marrow stromal cells are an integral component of the hematopoietic microenvironment and play a critical role in the regulation of hematopoietic stem cell proliferation and self-renewal. Exposure to nicotine decreased CD44 surface expression on primary bone marrow-derived fibroblastlike stromal cells and MS-5 stromal cell line, but not on hematopoietic cells. In addition, mainstream CS altered the trafficking of hematopoietic stem/progenitor cells (HSPC) in vivo. Exposure of mice to CS resulted in the inhibition of HSPC homing into bone marrow. Nicotine and cotinine treatment resulted in reduction of CD44 surface expression on lung microvascular endothelial cell line (LEISVO) and bone marrow-derived (STR-12) endothelial cell line. Nicotine treatment increased E-selectin expression on LEISVO cells, but not on STR-12 cells. These findings demonstrate that nicotine can modulate hematopoiesis by affecting the functions of the hematopoiesis-supportive stromal microenvironment, resulting in the inhibition of bone marrow seeding by LTC-ICs and interfering with stem cell homing by targeting microvascular endothelial cells.  相似文献   

11.
Human B-lymphopoiesis is supported by bone marrow-derived stromal cells   总被引:2,自引:0,他引:2  
We have recently reported an in vitro culture system that allows the clonal growth and differentiation of normal human bone marrow B-lineage cells. In the report presented here, we have used this B-cell colony assay to study the influence of cellular components of the human bone marrow microenvironment on B-lymphopoiesis. It is demonstrated that bone marrow stromal cells were able to provide all the necessary requirements for the growth and differentiation of B-lineage cells under the conditions of the B-cell colony assay. These stromal cells were obtained from long-term bone marrow cultures (LTBMC) that had been established from the spicules in human bone marrow. When these stromal cells were plated as an adherent underlayer in the double-agar B-cell colony assay, both immature and mature B-lineage cells were induced to differentiate into colonies containing cells that secreted immunoglobulin. The stromal cells from these spicule-derived LTBMCs maintained the capacity to support B-cell colony formation for up to 9 months.  相似文献   

12.
The low level of amphotropic retrovirus-mediated gene transfer into human hematopoietic stem cells (HSC) has been a major impediment to gene therapy for hematopoietic diseases. In the present study, we have examined amphotropic retrovirus receptor (amphoR) and ecotropic retrovirus receptor mRNA expression in highly purified populations of mouse and human HSC. Murine HSC with low to undetectable levels of amphoR mRNA and relatively high levels of ecotropic retrovirus receptor mRNA were studied. When these HSC were analyzed simultaneously for ecotropic and amphotropic retrovirus transduction, ecotropic provirus sequences were detected in 10 of 13 long-term repopulated animals, while amphotropic proviral sequences were detected in only one recipient. A second distinct population of murine HSC were isolated that express 3-fold higher levels of amphoR mRNA. When these HSC were analyzed simultaneously for ecotropic and amphotropic retrovirus transduction, 11 of 11 repopulated mice contained ecotropic provirus and 6 of 11 contained amphotropic provirus sequences, a significant increase in the amphotropic retrovirus transduction (P = 0.018). These results indicate that, among the heterogeneous populations of HSC present in adult mouse bone marrow, the subpopulation with the highest level of amphoR mRNA is more efficiently transduced by amphotropic retrovirus. In a related study, we found low levels of human amphoR mRNA in purified populations of human HSC (CD34+ CD38-) and higher levels in committed progenitor cells (CD34+ CD38+). We conclude that the amphoR mRNA level in HSC correlates with amphotropic retrovirus transduction efficiency.  相似文献   

13.
P F Hughes  C J Eaves  D E Hogge  R K Humphries 《Blood》1989,74(6):1915-1922
We used a helper-free recombinant retrovirus carrying the neomycin resistance (neor) gene to investigate methods for improving gene transfer efficiencies to clonogenic hematopoietic progenitor cells of human origin and to assess the possibility of gene transfer to the more primitive cells from which clonogenic cells are derived after several weeks in long-term human marrow cultures. The proportion of neor CFU-GM in methylcellulose assays of infected fresh marrow was increased by six- to eightfold (mean 37.4%) by the addition of extra GM colony-stimulating factor and interleukin-1 beta or medium conditioned by a human marrow "stromal" cell line to medium conditioned by agar-stimulated human leukocytes both during the infection and the colony growth period. Similar increases were also noted in the proportion of neor BFU-E, although the efficiencies overall were somewhat lower (up to 25.7%, mean 16.3%). Initiation of long-term cultures with marrow exposed to virus under the same growth factor-supplemented conditions but without any immediate selection step resulted in sustained production of a high proportion of neor CFU-GM and BFU-E for 6 weeks in both the nonadherent and adherent fractions. Molecular analysis was used to confirm the presence of the neo gene after culture. These results demonstrate that stable, high-efficiency gene transfer can be accomplished to the most primitive class of human hematopoietic cells currently detectable that may also have in vivo reconstituting potential. Further use of this approach should provide new insights into human hematopoietic stem cell regulation and allow continued development and assessment of gene therapy procedures.  相似文献   

14.
Croisille  L; Auffray  I; Katz  A; Izac  B; Vainchenker  W; Coulombel  L 《Blood》1994,84(12):4116-4124
Very primitive human hematopoietic progenitor cells are identified indirectly by their ability to give rise to clonogenic progenitors in the presence of either human or murine stromal cells. These long-term culture-initiating cell (LTC-IC) assays are usually performed in the presence of hydrocortisone based on the initial observation that hydrocortisone was required for prolonged hematopoiesis in standard long-term bone marrow cultures. In this report, we investigated the role of hydrocortisone in LTC-IC assays initiated with CD34++/CD38- cells seeded onto either human bone marrow LTC-derived adherent cells or a murine marrow-derived stromal cell line, MS-5. It was found that weekly addition of hydrocortisone to the cultures reduced the frequency of LTC-IC (from 1/5 to 1/20) calculated from limiting dilution experiments and also reduced fivefold to 10-fold the number of their progeny clonogenic cells detected after 4 to 5 weeks. In contrast, the frequency and differentiative potential of CD34++/CD38- grown in the presence of human marrow feeders was unaltered by the addition of glucocorticoids. Data are consistent with the hypothesis that hydrocortisone inhibited LTC-IC differentiation by downregulating the expression of a synergistic factor produced by MS-5 cells. (1) In the absence of hydrocortisone, the number of clonogenic progenitors generated by LTC-IC was much higher in cultures seeded on MS-5 than in cultures seeded on human marrow adherent cells, which was also true when cytokines were added to the cocultures. However, based on the phenotype of the colonies, progenitors produced in MS-5 cocultures were more mature than those generated on human marrow adherent cells. (2) Hydrocortisone counteracted the stimulatory effect of recombinant human cytokines (interleukin-3, interleukin-6, and steel factor) in assays performed on MS-5 but not on human marrow feeders. (3) Hydrocortisone led to a 50% decrease in the numbers of colony-forming units- granulocyte-macrophage found in methycellulose colony assays of CD34++/CD38- cells performed in the presence of MS-5 cells. Taken together, our results indicate that hydrocortisone acts differently on a murine stromal cell line and on marrow-derived human stromal cells and may suppress the expression by MS-5 cells of an activity selectively promoting amplification of clonogenic cells derived from primitive LTC-IC.  相似文献   

15.
16.
Isolation of a candidate human hematopoietic stem-cell population.   总被引:35,自引:8,他引:35       下载免费PDF全文
We have identified a rare (0.05-0.1%) subset of human fetal bone marrow cells that contains multipotent hematopoietic precursors. The population of human precursor cells that express Thy-1 and CD34 but no known lineage markers is enriched for clonogenic activity that establishes long-term, multilineage (myelomonocytic and B lymphoid) cultures on mouse marrow stromal lines. Further, the Thy-1+CD34+ subset that takes up little of the fluorescent mitochondrial dye rhodamine 123 contains virtually all the cells that establish long-term cultures. In human fetal thymus transplanted into SCID (severe combined immunodeficiency) mice, Thy-1+CD34+ fetal bone marrow cells differentiate into T lymphocytes. In two of nine cases, allogeneic Thy-1+CD34+ cells could engraft intact human fetal bone marrow grown in SCID mice, resulting in donor-derived myeloid and B cells. By extrapolation, the rare human Thy-1+Lin-CD34+ cell population contains pluripotent hematopoietic progenitors; we propose that it is highly enriched for candidate hematopoietic stem cells.  相似文献   

17.
Differences in the plastic adhesive properties of bone marrow (BM) cells were used to initiate modified stromal layers (MSL) from long-term cultures by removing non-adherent cells shortly (4 to 18 hours) after initial seeding. Following this early modification, adherent cells generated a confluent layer after 21 days of culture. Cellular characteristics of volume and spontaneous fluorescence determined by flow cytometry showed that the MSL included 82% fibroblastic stromal cells, 8% macrophages and 10% myelomonocytic cells. Furthermore, clonogenic assays revealed that the MSL were devoid of hematopoietic progenitor cells. MSL were found to sustain long-term myelopoiesis for at least 7 weeks from exogenously added hematopoietic progenitors isolated from bone marrow (CD34+ cells), thereby demonstrating their functionality. The present experimental model appears of interest for the study of interactions between defined populations of hematopoietic cells and cells of the adherent layer. Of importance, our present modifications of human long-term bone marrow culture are technically simple and do not involve manipulation of the stromal cells.  相似文献   

18.
The cytokines interleukin 1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) have been implicated in protecting normal hematopoiesis from both irradiation and chemotherapy damage. The mechanism of action of these cytokines and which cells are protected is not known. In this study, we report on the ability of IL-1 and TNF-alpha to protect hematopoietic cells capable of repopulating irradiated long-term bone marrow stromal cultures from 4-hydroperoxycyclophosphamide (4-HC). Irradiated long-term bone marrow cultures recharged with hematopoietic cells pretreated with IL-1 and TNF-alpha prior to 4-HC were shown to give rise to greater numbers of colony-forming cells at 4-5 weeks of culture within both the nonadherent and adherent cell populations of the long-term cultures when compared to controls. These results suggest that IL-1 and TNF-alpha can protect human long-term culture-initiating cells, which are closely related to reconstituting stem cells.  相似文献   

19.
Yao L  Yokota T  Xia L  Kincade PW  McEver RP 《Blood》2005,106(13):4093-4101
In vitro studies suggest that bone marrow endothelial cells contribute to multilineage hematopoiesis, but this function has not been studied in vivo. We used a Cre/loxP-mediated recombination to produce mice that lacked the cytokine receptor subunit gp130 in hematopoietic and endothelial cells. Although normal at birth, the mice developed bone marrow dysfunction that was accompanied by splenomegaly caused by extramedullary hematopoiesis. The hypocellular marrow contained myeloerythroid progenitors and functional repopulating stem cells. However, long-term bone marrow cultures produced few hematopoietic cells despite continued expression of gp130 in most stromal cells. Transplanting gp130-deficient bone marrow into irradiated wild-type mice conferred normal hematopoiesis, whereas transplanting wild-type bone marrow into irradiated gp130-deficient mice did not cure the hematopoietic defects. These data provide evidence that gp130 expression in the bone marrow microenvironment, most likely in endothelial cells, makes an important contribution to hematopoiesis.  相似文献   

20.
OBJECTIVE: Low-dose methotrexate (MTX) is often used in the treatment of rheumatoid arthritis (RA). To be effective, treatment must be long-term, and there are concerns that MTX may impair bone formation in a population already predisposed to osteoporosis. The purpose of this investigation was to determine the direct effects of MTX at clinically relevant doses on the growth and differentiation of human cells of the osteoblast (bone-forming) lineage. METHODS: Cells derived from the marrow stroma (BMSC) and trabecular surfaces [human bone-derived cells (HBDC)] of adult ribs were cultured in the absence or presence of MTX (1-1000 nM). To promote the differentiation and further maturation of cells of the osteoblast lineage, one half of the cultures were treated additionally with 10 nM dexamethasone (Dx). RESULTS: In cultures of BMSC, treatment with MTX (+/-Dx) did not affect the total number of colonies that formed or the expression of the developmental markers STRO-1 and alkaline phosphatase (AP). At concentrations > or =10 nM, however, there was a statistically significant reduction in the number of cells harvested at the end of primary culture. In cultures of HBDC, treatment with MTX (in the presence of Dx) did not affect cell number or the expression of AP. CONCLUSIONS: At concentrations > or =10 nM, treatment with MTX inhibits the proliferation of primitive marrow stromal cells, but not their ability to undergo osteogenic differentiation. The proliferation and further maturation of cells of the osteoblast lineage is not affected by treatment with MTX. These findings are reassuring for clinicians using MTX in the treatment of RA.  相似文献   

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