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L Guilbert

Publications and source records attributed to L Guilbert.

14 recordsLinked to original sources
PubMed2002

Growth factor rescue of cytokine mediated trophoblast apoptosis.

INTRODUCTION: Apoptosis can be induced in cytotrophoblasts and syncytiotrophoblast in culture by a combination of TNF-alpha and IFN-gamma (Yui et al., 1994a; Garcia-Lloret et al., 1996). This apoptotic action of TNF-alpha and IFN-gamma can be inhibited/'rescued' by EGF (Garcia-Lloret et al., 1996). Additional 'survival' factors have been sought which might protect cells against apoptosis induced by TNF-alpha/IFN-gamma. The survival factors investigated were bFGF, IGF-1, PDGF-AA, VEGF and PLGF. These cytokines were chosen specifically because in common with EGF, the receptors for these molecules are all direct protein tyrosine kinases. MATERIALS AND METHODS: All the experiments were carried out using a standard cell culture protocol (Yui et al., 1994a, b; Garcia-Lloret et al., 1996). Apoptosis was induced using TNF-alpha/IFN-gamma, and rescue was attempted using the various cytokines. Apoptosis was identified using the TUNEL technique and quantified by counting 3000 cells in each experimental well. RESULTS: As in previous studies EGF produced a complete inhibition of the apoptotic action of TNF-alpha/IFN-gamma. bFGF, IGF-1, and PDGF-AA produced a partial but significant inhibition of the apoptotic action of TNF-alpha/IFN-gamma. VEGF and PLGF in these experiments had no protective effects against TNF-alpha/IFN-gamma induced apoptosis. DISCUSSION: Previous studies relating to EGF have been confirmed. bFGF, IGF-1, and PDGF have all been shown to provide partial protection against TNF-alpha/IFN-gamma induced apoptosis. VEGF and PLGF did not protect against apoptosis, and the mechanisms of action remain unclear.

Apoptosis↗
PubMed1993

Synthesis of T helper 2-type cytokines at the maternal-fetal interface.

Clinical and experimental evidence has indicated that the maternal immune response is biased toward antibody production and away from cell-mediated immunity during pregnancy, especially in the vicinity of the fetoplacental unit. Because antibody responses are often associated with the Th2 cytokine pattern, this suggests that Th2-type cytokines might predominate locally in the regulation of the maternal immune response. In order to test this hypothesis, we examined the local and distal release of cytokines during murine pregnancy using ELISA assays. We report here that the Th2-specific cytokines IL-4, IL-5, and IL-10 were readily detectable in cell supernatants derived from fetal-placental units in all three trimesters of gestation. IL-3 was also present. These cytokines were detected in lysates of freshly isolated, day 12 decidual and placental cells, and in supernatants as early as 15 min after the beginning of culture. The presence of functional IL-10 was confirmed by specific bioassay. IL-10 mRNA was localized to the decidua at day 6 of gestation by in situ hybridization. IFN-gamma was also found in the supernatants from the first trimester of pregnancy, but was barely detectable in the second, and undetectable in the third trimester. Cytokine expression was consistently detected in samples from individual mice. None of these cytokines was produced by unstimulated spleen or mesenteric lymph nodes from pregnant mice. IL-4, IL-10, and IFN-gamma were produced by Con A-stimulated spleen cells from virgin mice, but in ratios opposite to those found in the placenta. These observations indicate that Th2-specific cytokines are normally produced at the maternal-fetal interface. The continuous presence of IL-4, IL-5, and IL-10, with early and transient expression of IFN-gamma, can provide a molecular basis for the antibody/Th2-like bias of the maternal immune response during pregnancy.

Animals↗
PubMed1993

CSF-1 stimulates nucleoside transport in S1 macrophages.

We have examined nucleoside transport (NT) in a cell line derived from primary day 7 murine bone marrow macrophages (S1 macrophages) in response to the macrophage growth factor, colony-stimulating factor 1 (CSF-1). Adenosine and uridine transport in quiescent S1 macrophages occurred primarily by two facilitated diffusional routes, one that was sensitive and one that was relatively resistant to the inhibitor nitrobenzylthioinosine (NBMPR). Addition of CSF-1 to quiescent cultures resulted in increased adenosine and uridine transport with biphasic kinetics with respect to the cell cycle. Basal NT activity was elevated (about twofold) within 15 min of CSF-1 addition, returned to near basal levels by 1 h, and then increased again (three- to fourfold) 8-12 h later, returning again to basal levels by 48 h post CSF-1 stimulation. We propose that the large increase in NT activity at 8-12 h corresponded with the time when cultures synchronously began to enter the S phase of the cell cycle. In addition to these changes in the absolute rates, the proportions of NBMPR-sensitive and NBMPR-insensitive transport also change after CSF-1 addition. Quiescent cultures exhibited primarily NBMPR-insensitive transport while logrithmically growing cultures exhibited primarily NBMPR-sensitive nucleoside transport activity. The increase in the NBMPR-sensitive component of the transport process paralleled a similar increase in the number of high-affinity NBMPR binding sites, suggesting that the mechanism for upregulating NBMPR-sensitive NT activity involves increases in the number of NBMPR-sensitive transporter sites. Interestingly, we were unable to detect Na(+)-dependent concentrative uptake of adenosine, uridine, or formycin-B either in the S1 macrophage cell line or in primary (day 7) murine macrophages. Thus these bone marrow derived macrophages did not display the characteristically large Na(+)-dependent transport systems observed by others in peritoneal macrophages, implying that these two populations of macrophages are, indeed, functionally distinct.

3-O-Methylglucose↗
PubMed1993

The trophoblast as an integral component of a macrophage-cytokine network.

The trophoblast, an epithelial cell of fetal origin that forms the physical barrier between the mother and developing conceptus, becomes a component of the host immune system during pregnancy. Of the classical immune cells, it most closely resembles the macrophage, also present in high numbers in the pregnant uterus. The macrophage and trophoblast, as cell classes, share characteristics such as phagocytosis, syncytialization, invasiveness, expression of the proteins CD4, CD14, IgG receptor (FcR), non-specific esterase, granulocyte macrophage-CSF (GM-CSF), colony stimulating factor 1 (CSF-1), interleukin-1 (IL-1), interleukin-6 (IL-6), tumour necrosis factor (TNF-alpha), transforming growth factors (TGF), platelet-alpha derived growth factor (PDGF) and receptors for these cytokines. In the uterus both cell types appear regulated by a common element, the uterine epithelium, that secretes cytokines such as CSF-1, GM-CSF, TNF alpha, TGF beta, IL-6, and leukaemia inhibitory factor (LIF) that target both macrophages and trophoblasts. The common characteristics and regulation that make teleological sense in terms of co-ordinating local uterine immunity during pregnancy may also be important in transmission of congenital diseases such as AIDS. The production by the uterine epithelium of a number of cytokines previously only associated with mononuclear phagocyte production and function predicts the existence of a similar, but broader, shared cytokine network encompassing trophoblast and the principal immune regulatory cell, the T lymphocyte.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Different molecular mechanisms lead to same endpoints with different function: TNF-alpha induces non-functional CSF-1 receptors on HL-60 cells in contrast to interferon-gamma.

Tumour necrosis factor-alpha (TNF-alpha) induces differentiation on human promyelocytic leukemia cells (HL-60) as assessed by growth inhibition accompanied by reduction of c-myc levels, and expression of surface colony-stimulating factor-1 (CSF-1) receptors reported as molecular markers for acute myeloid leukemia (AML). CSF-1 receptors can be readily demonstrated by direct binding of 125I-CSF-1 and expression of v-fms whose gene product retains a complete ligand binding domain. Although the same findings have been previously demonstrated on HL-60 cells after interferon-gamma (IFN-gamma) treatment, the major difference between the two pathways of cellular differentiation is the functional state of the induced receptors: when IFN-gamma is used as differentiation agent, the cells are driven to express a high number of CSF-1 receptors and are able to respond to a CSF-1 stimulus. Such mitogenic response is not obtained when TNF-alpha is applied as inducer indicating that the newly expressed receptors are not functional. This difference may be due to different molecular mechanisms the two factors trigger in order to reach the same endpoint: the maturation of this leukemic population.

Cell Differentiation↗
PubMed1990

Expression of novel cytokine transcripts in the murine placenta.

It is increasingly apparent that lymphohematopoietic cytokines play a unique role during gestation. For example, placentally derived cells, including trophoblast and choriocarcinomas, respond to granulocyte-macrophage (GM)/colony-stimulating factor (CSF) and to colony-stimulating factor 1 (CSF-1), both formerly considered to be hematopoietic cytokines. It has been shown that CSF-1 is produced by the uterine epithelium and GM-CSF by the decidua. However, evidence is emerging that placentally derived cytokines may also influence reproductive function, and the question arises whether anything unique about their expression allows them to function in this particular environment. We have therefore analyzed the expression of cytokine genes in the murine placenta using a panel of cDNA probes that detect GM-CSF, CSF-1, tumor necrosis factor (TNF), interleukin (IL)-1, IL-2, IL-3, and IL-5. We report here the detection of mRNA encoding IL-1, TNF, and CSF-1 that are identical in size to those found in macrophage and fibroblast cell lines. In contrast, five distinct GM-CSF transcripts, four of which are larger than T-cell GM-CSF transcripts, were present. These novel transcripts ranged in size from 5.2, 3.9, 2.4, and 2.1 to 1 kb. Restriction analysis did not reveal any major structural alterations in the placental GM-CSF gene. Thus, the unique placental GM-CSF mRNAs detected most likely result from modified transcription of the GM-CSF gene in the placenta rather than transcription from a modified placental GM-CSF gene. Transcription of enkaryotic genes involves a number of regulatory mechanisms that can generate functionally and structurally diverse polypeptides from a single gene. Modified transcription of the GM-CSF gene in the placenta may serve to generate functionally diverse cytokines which provide the growth and differentiation signals that help to sustain pregnancy. This observation may clarify the unique role played by GM-CSF in reproductive function.

Animals↗
PubMed1988

Growth response of human myeloid leukemia cells to colony-stimulating factors.

The effects of human recombinant granulocyte and granulocyte-macrophage- (G- and GM-CSF), and of purified macrophage-stimulating factors (CSF-1), were tested on populations of leukemia cells isolated from 18 patients with different types of acute myeloid leukemia. Cell proliferation and differentiation were studied by culturing the cells in suspension for 7 days in the presence of CSF or medium alone. Spontaneous cell proliferation, as assessed by tritiated thymidine uptake, was observed in 9 of the 18 cases. GM-CSF induced proliferation in seven of the nine cases without spontaneous growth and increased spontaneous proliferation in nine cases. G-CSF added alone was also found to strongly stimulate leukemic blast cell proliferation, in which a translocation involving the long arm of chromosome 17 was observed. Low levels of CSF-1 stimulation were also observed in some cases. No clear morphological modification supporting evidence of terminal differentiation was observed, whereas modulation of some cell surface antigens was detected by flow cytometry. Thus, most leukemia cells still depend on growth factors for their proliferation, GM-CSF appearing the most effective. On the other hand these factors were not able to induce terminal differentiation.

Antigens, Surface↗
PubMed1987

The immunostimulatory effect of T cells and T cell lymphokines on murine fetally derived placental cells.

Evidence for maternal immune recognition of the fetus can be found during pregnancy, yet the conceptus remains unharmed. Indeed, in some cases immunizing the mother with cells sharing histocompatibility antigens with the fetus is beneficial to fetal survival. This could be due to the effect of maternally derived lymphokines on placental growth and function, according to the immunostimulation hypothesis. We demonstrate here that placental cells in culture proliferate upon the addition of T cell-derived lymphokines. The lymphokine activity has been separated from IL 2 and B cell growth factor, and copurified with IL 3 and granulocyte-macrophage colony-stimulating factor (CSF-GM). Recombinant CSF-GM and recombinant IL 3 showed a similar effect. The placental cells that proliferate in culture are of fetal origin and are characterized by strong adherence, phagocytosis, nonspecific esterase staining, and response to the macrophage-specific colony-stimulating factor CSF-1. In addition, treatment of pregnant females with anti-thymocyte serum as well as anti-Ly-2.1 monoclonal antibody, at gestational times before Ly-2 antigen appearance in the fetus, leads to a reduction of the proliferative and phagocytic capacity of day 12 placentae. These results clearly demonstrate that maternal T cells act upon fetally derived placental cells to improve their proliferative and phagocytic potential, and thus provide evidence for the immunostimulatory role of these cells during pregnancy.

Animals↗
PubMed1984

Differential expression of c-fos in hematopoietic cells: correlation with differentiation of monomyelocytic cells in vitro.

Among various neonatal mouse tissues, elevated levels of c-fos transcripts have been detected in crude preparations of bone. Here, we show that c-fos expression originates in the bone marrow, and to a lesser extent in adherent cells (macrophages). High levels of c-fos expression were also detected in primary cultures of differentiated bone marrow-derived macrophages, but not in cell lines resembling immature hematopoietic cells. However, when the human promyelocytic cell line HL60 was induced in vitro to differentiate into macrophages, c-fos expression was readily detectable. These findings suggest that c-fos expression in mononuclear phagocytic cells is restricted to late stages of differentiation. This pattern of c-fos expression is in marked contrast to those of the c-myb and c-myc genes which are transcriptionally active predominantly in precursor cells. In the amnion, where c-fos expression increases to high levels at late stages of gestation, synthesis of c-fos protein occurs in cells that do not resemble macrophages. It thus appears that c-fos expression in several distinct cell types is correlated with differentiation processes.

Amnion↗
PubMedDate not supplied

Induction of c-fos during myelomonocytic differentiation and macrophage proliferation.

Previous studies have suggested a role for c-fos in cellular differentiation in fetal membranes, haematopoietic cells and teratocarcinoma stem cells. In other cell types, such as fibroblasts, c-fos expression is normally very low, but is rapidly induced by peptide growth factors, implicating c-fos in growth control mechanisms. Here, we show that the TPA (12-O-tetradecanoylphorbol-13-acetate)-induced macrophage-like differentiation of HL60 human promyelocytic precursor cells is accompanied by the induction of both c-fos mRNA and protein within 15 min after treatment, suggesting a functional role for c-fos in this differentiation system. In quiescent terminally differentiated macrophages, expression of c-fos is inducible by the macrophage-specific growth factor colony-stimulating factor-1 (CSF-1). The kinetics of c-fos induction, however, are entirely different from those in growth factor-stimulated fibroblasts, supporting the view that the c-fos gene product may serve different functions in different cell types.

Cell Differentiation↗
PubMedDate not supplied

Disseminated Fusarium solani infection with endocarditis in a lung transplant recipient.

Eleven days after double lung transplantation for cystic fibrosis, an 18-year-old patient developed a disseminated Fusarium solani infection with tricuspid valve endocarditis. This infection occurred under fluconazole and immunosuppressive therapy with cyclosporin, prednisone and azathioprine, with a normal leucocyte count. Liposomal amphotericin B allowed blood culture negativation. The patient died from a bacterial septic shock.

Adolescent↗