Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.2 (focal adhesion kinase)
44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously reported the development of in vivo functional assays for primitive human hematopoietic cells based on their ability to repopulate the bone marrow (BM) of severe combined immunodeficient (SCID) and nonobese diabetic/SCID (NOD/SCID) mice following intravenous transplantation. Accumulated data from gene marking and cell purification experiments indicate that the engrafting cells (defined as SCID-repopulating cells or SRC) are biologically distinct from and more primitive than most cells that can be assayed in vitro. Here we demonstrate through limiting dilution analysis that the NOD/SCID xenotransplant model provides a quantitative assay for SRC. Using this assay, the frequency of SRC in cord blood (CB) was found to be 1 in 9.3 x 10(5) cells. This was significantly higher than the frequency of 1 SRC in 3.0 x 10(6) adult BM cells or 1 in 6.0 x 10(6) mobilized peripheral blood (PB) cells from normal donors. Mice transplanted with limiting numbers of SRC were engrafted with both lymphoid and multilineage myeloid human cells. This functional assay is currently the only available method for quantitative analysis of human hematopoietic cells with repopulating capacity. Both CB and mobilized PB are increasingly being used as alternative sources of hematopoietic stem cells in allogeneic transplantation. Thus, the findings reported here will have important clinical as well as biologic implications.
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PMID:Primitive human hematopoietic cells are enriched in cord blood compared with adult bone marrow or mobilized peripheral blood as measured by the quantitative in vivo SCID-repopulating cell assay. 916 28

Many experimental and clinical protocols are being developed that involve ex vivo culture of human hematopoietic cells on stroma or in the presence of cytokines. However, the effect of these manipulations on primitive hematopoietic cells is not known. Our severe combined immune-deficient mouse (SCID)-repopulating cell (SRC) assay detects primitive human hematopoietic cells based on their ability to repopulate the bone marrow (BM) of immune-deficient non-obese diabetic/SCID (NOD/SCID) mice. We have examined here the maintenance of SRC, colony-forming cells (CFC), and long-term culture-initiating cells (LTC-IC) during coculture of adult human BM or umbilical cord blood (CB) cells with allogeneic human stroma. Transplantation of cultured cells in equivalent doses as fresh cells resulted in lower levels of human cell engraftment after 1 and 2 weeks of culture for BM and CB, respectively. Similar results were obtained using CD34+-enriched CB cells. By limiting dilution analysis, the frequency of SRC in BM declined sixfold after 1 week of culture. In contrast to the loss of SRC as measured by reduced repopulating capacity, the transplanted inocula of cultured cells frequently contained equal or higher numbers of CFC and LTC-IC compared with the inocula of fresh cells. The differential maintenance of CFC/LTC-IC and SRC suggests that SRC are biologically distinct from the majority of these in vitro progenitors. This report demonstrates the importance of the SRC assay in the development of ex vivo conditions that will allow maintenance of primitive human hematopoietic cells with repopulating capacity.
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PMID:Differential maintenance of primitive human SCID-repopulating cells, clonogenic progenitors, and long-term culture-initiating cells after incubation on human bone marrow stromal cells. 922 64

In vitro studies have provided little consensus on the kinetic abnormality underlying the myeloid expansion of chronic myelogenous leukemia (CML). Transplantation of human CML cells into non-obese diabetic mice with severe immunodeficiency disease (NOD/SCID mice) may therefore be a useful model. A CML cell line (BV173) and peripheral blood cells collected from CML patients in chronic phase (CP), accelerated phase (AP), or blastic phase (BP) were injected into preirradiated NOD/SCID mice. Animals were killed at serial intervals; cell suspensions and/or tissue sections from different organs were studied by immunohistochemistry and/or flow cytometry using antihuman CD45 monoclonal antibodies (MoAbs), and by fluorescence in situ hybridization (FISH) for the BCR-ABL fusion gene. One hour after injection, cells were sequestered in the lungs and liver, but 2 weeks later they were no longer detectable in either site. Similar short-term kinetics were observed using 51Cr-labeled cells. The first signs of engraftment for BV173, AP, and BP cells were detected in the bone marrow (BM) at 4 weeks. At 8 weeks the median percentages of human cells in murine marrow were 4% (range, 1 to 9) for CP, 11% (range, 5 to 36) for AP, 38.5% (range, 18 to 79) for BP, and 54% (range, 31 to 69) for BV173. CP cells progressively infiltrated BM (21%) and spleen (6%) by 18 to 20 weeks; no animals injected with the cell line or BP cells survived beyond 12 weeks. The rate of increase in human cell numbers was higher for BP (7.3%/week) as compared with CP (0.9%/week) and AP (0. 5%/week). FISH analysis with BCR and ABL probes showed that some of the human cells engrafting after injection of CP cells lacked a BCR-ABL gene and were presumably normal. We conclude that CML cells proliferate in NOD/SCID mice with kinetics that recapitulate the phase of the donor's disease, thus providing an in vivo model of CML biology.
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PMID:The kinetics and extent of engraftment of chronic myelogenous leukemia cells in non-obese diabetic/severe combined immunodeficiency mice reflect the phase of the donor's disease: an in vivo model of chronic myelogenous leukemia biology. 969 28

The detection of primitive hematopoietic cells based on repopulation of immune-deficient mice is a powerful tool to characterize the human stem-cell compartment. Here, we identify a newly discovered human repopulating cell, distinct from previously identified repopulating cells, that initiates multilineage hematopoiesis in NOD/SCID mice. We call such cells CD34neg-SCID repopulating cells, or CD34neg-SRC. CD34neg-SRC are restricted to a Lin-CD34-CD38- population without detectable surface markers for multiple lineages and CD38 or those previously associated with stem cells (HLA-DR, Thy-1 and CD34). In contrast to CD34+ subfractions, Lin-CD34-CD38- cells have low clonogenicity in short-and long-term in vitro assays. The number of CD34neg-SRC increased in short-term suspension cultures in conditions that did not maintain SRC derived from CD34+ populations, providing independent biological evidence of their distinctiveness. The identification of this newly discovered cell demonstrates complexity of the organization of the human stem-cell compartment and has important implications for clinical applications involving stem-cell transplantation.
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PMID:A newly discovered class of human hematopoietic cells with SCID-repopulating activity. 973 90

Retrovirus-mediated gene transfer into long-lived human pluripotent hematopoietic stem cells (HSCs) is a widely sought but elusive goal. A major problem is the quiescent nature of most HSCs, with the perceived requirement for ex vivo prestimulation in cytokines to induce stem cell cycling and allow stable gene integration. However, ex vivo culture may impair stem cell function, and could explain the disappointing clinical results in many current gene transfer trials. To address this possibility, we examined the ex vivo survival of nonobese diabetic/severe combined immune-deficient (NOD/SCID) repopulating cells (SRCs) over 3 days. After 1 day of culture, the SRC number and proliferation declined twofold, and was further reduced by day 3; self-renewal was only detectable in noncultured cells. To determine if the period of ex vivo culture could be shortened, we used a vesicular stomatitis virus G protein (VSV-G) pseudotyped retrovirus vector that was concentrated to high titer. The results showed that gene transfer rates were similar without or with 48 hours prestimulation. Thus, the use of high-titer VSV-G pseudotyped retrovirus may minimize the loss of HSCs during culture, because efficient gene transfer can be obtained without the need for extended ex vivo culture.
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PMID:One-day ex vivo culture allows effective gene transfer into human nonobese diabetic/severe combined immune-deficient repopulating cells using high-titer vesicular stomatitis virus G protein pseudotyped retrovirus. 1009 Sep 30

Nonobese diabetic/severe combined immune deficiency (NOD/SCID) mouse repopulating cells (SRC) have been proposed to represent a more primitive human stem cell subset than the cobblestone area-forming cell (CAFC) week (wk) 6 or the long-term culture-initiating cell (LTC-IC) wk 5 on the basis of their difference in frequency, phenotype, transfectibility, and multilineage outgrowth potential in immunodeficient recipients. We have assessed the percentage of various progenitor cell populations (colony-forming cell [CFC] and CAFC subsets) contained in unsorted NOD/SCID BM nucleated cells (nc), human umbilical cord blood (UCB) nc, bone marrow (BM) nc, peripheral blood stem cells (PBSC), and CD34(+) selected UCB nc, seeding in the BM and spleen of NOD/SCID mice within 24 hours after transplantation. The seeding efficiency of NOD/SCID BM CAFC wk 5 was median (range) in the spleen 2.9% (0.7% to 4.0%) and in the total BM 8.7% (2.0% to 9.2%). For human unsorted UCB nc, BM nc, PBSC, and CD34(+) UCB cells, the seeding efficiency for CAFC wk 6 in the BM of NOD/SCID mice was 4.4% (3.5% to 6.3%), 0.8% (0.3% to 1.7%), 5.3% (1. 4% to 13.6%), and 4.4% (3.5% to 6.3%), respectively. Using flow cytometry, the percentage CD34(+) UCB cells retrieved from the BM of sublethally or supralethally irradiated NOD/SCID mice was 2.3 (1.4 to 2.8) and 2.5 (1.6 to 2.7), respectively. Because we did not observe any significant differences in the seeding efficiencies of the various stem cell subsets, it may be assumed that the SRC seeding efficiency in NOD/SCID mice is similarly low. Our data indicate that the seeding efficiency of a graft can be of great influence when assessing stem cell frequencies in in vivo repopulation assays.
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PMID:Seeding efficiency of primitive human hematopoietic cells in nonobese diabetic/severe combined immune deficiency mice: implications for stem cell frequency assessment. 1055 89

BCR-ABL is a chimeric oncogene generated by translocation of sequences from the chromosomal counterpart (c-ABL gene) on chromosome 9 into the BCR gene on chromosome 22. Alternative chimeric proteins, BCR-ABL(p190) and BCR-ABL(p210), are produced that are characteristic of chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(1)-ALL). In CML, the transformation occurs at the level of pluripotent stem cells. However, Ph(1)-ALL is thought to affect progenitor cells with lymphoid differentiation. Here we demonstrate that the cell capable of initiating human Ph(1)-ALL in non-obese diabetic mice with severe combined immunodeficiency disease (NOD/SCID), termed SCID leukemia-initiating cell (SL-IC), possesses the differentiative and proliferative capacities and the potential for self-renewal expected of a leukemic stem cell. The SL-ICs from all Ph(1)-ALL analyzed, regardless of the heterogeneity in maturation characteristics of the leukemic blasts, were exclusively CD34(+ )CD38(-), which is similar to the cell-surface phenotype of normal SCID-repopulating cells. This indicates that normal primitive cells, rather than committed progenitor cells, are the target for leukemic transformation in Ph(1)-ALL.
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PMID:A primitive hematopoietic cell is the target for the leukemic transformation in human philadelphia-positive acute lymphoblastic leukemia. 1078 38

The growth factor combination containing early acting cytokines FLT-3 ligand (FL), Stem Cell Factor (SCF) and thrombopoietin (TPO) is able to maintain, for an extended culture period, early stem cells, defined as long-term repopulating NOD/SCID mice (Scid Repopulating Cell-SRC) contained in cord blood (CB). In this culture system, the role of IL-6 and IL-3 has not been clearly established. Using a combination of FL+TPO+SCF with or without IL-6, we were able to form CB CD34+ cells for 30 weeks. The CB CD34+ cells cultured in this system engrafted NOD/SCID mice after 6 weeks of culture; the cells from primary recipients were also able to engraft secondary NOD/SCID mice. When CB CD34+ cells were cultured in the presence of IL-3 in the place of IL-6 we observed an even better expansion of cells and a similar clonogenic progenitor output in the first 8 weeks of culture. However, more primitive LTC-IC output increased up to week 6 with the growth factor combination containing IL-3 and then decreased and disappeared, while with the growth factor combination with or without IL-6 increased up to week 23. Cells cultured for 4 weeks with the 4-factor combination containing IL-3 engrafted NOD/SCID mice less efficiently. Repopulation of NOD/SCID mice was no longer observed when ex vivo expansion was performed for 6 weeks. This study provides some evidence that no differences could be detected in long-term maintenance and even expansion of human primitive cord blood cells cultured with FL+TPO+SCF in the presence or absence of IL-6. Under the culture conditions employed in this study, the presence of IL-3 reduced the repopulating potential of expanded CB CD34+ cells.
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PMID:Different growth factor requirements for the ex vivo amplification of transplantable human cord blood cells in a NOD/SCID mouse model. 1138 43

Human haemopoietic stem and progenitor cells may be distinguished by the pattern of cell surface markers they display. The cells defined as 'stem' cells are heterogeneous and lack specific markers for their detection. However, they may be identified in in vitro assays such as the long-term culture initiating cell (LTC-IC) and in transplant assays involving immunosuppressed NOD/SCID mice. It is still not clear to what extent, if any, these cell populations overlap. The chemokine macrophage inflammatory protein-1alpha (MIP-1alpha) prolongs survival of LTC-IC in suspension cultures and we now show that in longterm bone marrow cultures (LTBMC) maintenance of haemopoiesis was significantly better from the CD34+ cells which possess MIP-1alpha receptors (P < 0.006). We examined one MIP-1alpha receptor, CCR1, which is present on CD34+ cells from haemopoietic tissues. In LTBMC the production of GM-CFC from CD34+CCR1- cells was significantly higher (P < 0.02) than that from CD34+CCR1+ cultures and the incidence of LTC-IC was 3- to 6-fold higher in the CD34+CCR1- cell fraction. In contrast, the cells responsible for high levels of engraftment in NOD/SCID mice were contained in the CD34+CCR1+ cell fraction. The CD34+CCR1+ cells engrafted to high levels in NOD/SCID and generated large numbers of progenitor cells. Therefore, we conclude that LTC-IC and SRC may be distinguished on the basis of expression of the chemokine receptor CCR1.
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PMID:NOD/SCID repopulating cells but not LTC-IC are enriched in human CD34+ cells expressing the CCR1 chemokine receptor. 1145 79

The migration of immunocytes within the extracellular matrix (ECM) is influenced by the activation state of the incoming cell and its responses to the presence of chemokines and cytokines. We studied the regulatory role of TGF-beta1 on T cell homing to secondary lymphatic organs, such as the spleen, and chemotaxis within an ECM-like environment in using an ECM-like 3-dimensional gel system designed to follow the migration of individual leukocytes along chemokine gradients in real time. The numbers of migrating naive, but not memory T cells toward SDF-1alpha markedly increased after pre-incubating the cells with TGF-beta1 (0.25 ng/ml) for 24 h. The mechanisms underlying TGFbeta1-modulated migration involve the up-regulation of the expression of the SDF-1alpha receptor CXCR4, the enhancement of the SDF-1alpha-induced actin polymerization, and increased phosphorylation of Pyk2, a focal adhesion kinase involved in integrin-mediated lymphocyte migration, adhesion and interactions with ECM. Interestingly, priming of naive human T cells with TGF-beta1 increased homing of these cells to the spleen of NOD/SCID mice in a CXCR4-dependent manner. We propose that the effect of TGF-beta1 on the chemotaxis of naive T cells may be important in the locomotion of naive T cells toward SDF-1alpha-rich niches.
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PMID:TGF-beta1 enhances SDF-1alpha-induced chemotaxis and homing of naive T cells by up-regulating CXCR4 expression and downstream cytoskeletal effector molecules. 1175 60


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