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G Migliaccio

Publications and source records attributed to G Migliaccio.

At least 91 records · Page 5Linked to original sources
PubMed1989

Biosynthesis, membrane translocation, and surface expression of Sindbis virus E1 glycoprotein.

Sindbis virus glycoproteins PE2 (precursor of E2) and E1 are coded in this order by the same monocistronic mRNA, cotranslationally inserted in the endoplasmic reticulum membrane and then transported to the cell surface where the progeny virus is released by budding. In the virion, three E1 plus three E2 molecules form hexameric spike complexes. Previous work (S. Bonatti, G. Migliaccio, G. Blobel, and P. Walter (1984), Eur. J. Biochem. 140, 499-502) revealed a single signal sequence for cotranslational translocation located at the aminoterminus of PE2. We have generated progressive deletions of the coding region upstream of E1 and have engineered the resulting cDNAs in plasmids suitable for in vitro transcription/translation and in vivo expression. The results we obtained with this approach show that (i) internal signal sequence(s) are present upstream of E1, and this protein may be generated and inserted in the endoplasmic reticulum membrane independently of the PE2 signal sequence; and (ii) E1 is efficiently transported to the plasma membrane in the absence of PE2/E2; exit from the endoplasmic reticulum of E1 takes place with almost the same timing in the presence or in the absence of PE2.

Animals↗
PubMed1989

Selection of lineage-restricted cell lines immortalized at different stages of hematopoietic differentiation from the murine cell line 32D.

Erythropoietin (Epo), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor- (G-CSF) dependent cell lines have been derived from the murine hematopoietic cell line 32D with a selection strategy involving the culture of the cells in FBS-deprived medium supplemented only with pure recombinant Epo, GM-CSF, or G-CSF. The cells retain the diploid karyotype of the original 32D clone, do not grow in the absence of exogenous growth factor, and do not induce tumors when injected into syngeneic recipients. The morphology of the Epo-dependent cell lines (32D Epo1, -2, and -3) was heterogeneous and evolved with passage. The percent of differentiated cells also was a function of the cell line investigated. Benzidine-positive cells ranged from 1-2% (32D Epo3) to 50-60% (32D Epo1). These erythroid cells expressed carbonic anhydrase I and/or globin mRNA but not carbonic anhydrase II. The GM-CSF- and G-CSF-dependent cell lines had predominantly the morphology of undifferentiated myeloblasts or metamyelocytes, respectively. The GM-CSF-dependent cell lines were sensitive to either GM-CSF or interleukin-3 (IL-3) but did not respond to G-CSF. The G-CSF-dependent cell lines grew to a limited extent in IL-3 but did not respond to GM-CSF. These results indicate that the cell line 32D, originally described as predominantly a basophil/mast cell line, has retained the capacity to give rise to cells which proliferate and differentiate in response to Epo, GM-CSF, and/or G-CSF. These cells represent the first nontransformed cell lines which can be maintained in growth factors other than IL-3 and which differentiate in the presence of physiologic signals. As such, they may represent a model to study the molecular mechanisms underlying the process of hematopoietic differentiation, as well as sensitive targets for bioassays of specific growth factors.

Animals↗
PubMed1989

Regulation of differentiation of murine progenitor cells derived from blast cell colonies under serum-deprived conditions.

We have examined the effect of interleukin 3 (IL-3), granulocyte-macrophage (GM)-, granulocyte (G)-, and macrophage (M)-colony-stimulating factors (CSFs) on the induction of GM colonies from highly enriched murine hematopoietic progenitor cells under serum-deprived conditions. Each growth factor was tested alone or in combination with suboptimal concentrations of the others. The effect of each CSF on GM colony growth in fetal bovine serum (FBS)-supplemented cultures of unfractionated marrow cells is reported for comparison. GM-CSF induced GM colony growth in serum-deprived cultures of purified progenitor cells to the same extent as in FBS-supplemented cultures of unfractionated marrow cells. In contrast, IL-3 was only one-tenth as active in promoting the growth of enriched progenitor cells under serum-deprived conditions when compared with its effect on colony growth from unfractionated marrow. M-CSF and G-CSF were almost completely ineffective in both cases. G-CSF induction of GM colony growth from purified progenitor cells was restored by addition of suboptimal concentrations of IL-3 or GM-CSF, suggesting that either IL-3 or GM-CSF is required to observe the effect of G-CSF. Addition of G-CSF to GM-CSF-stimulated cultures did not increase the maximal number of colonies detected, indicating that these two growth factors may act on the same subset of progenitor cells. Addition of GM-CSF or IL-3 to IL-3- or GM-CSF-stimulated cultures, respectively, increased by 40% the maximal number of colonies detected, suggesting that these two factors act on at least partially separate subsets of GM progenitors. These data parallel the recent observations on the control of human GM colony formation under FBS-deprived conditions and support a model for the control of myeloid differentiation that requires the interplay of different growth factors.

Animals↗
PubMed1988

Human embryonic hemopoiesis: control mechanisms underlying progenitor differentiation in vitro.

In order to investigate differences in control mechanisms between embryonic and adult hemopoiesis, we have studied the sensitivity of human embryonic progenitors (5-8 weeks postconception) to either positive (erythropoietin (Ep), granulocyte-macrophage colony-stimulating factor (GM-CSF) and insulin-like growth factor 1 (IGF-1] or negative (tumor necrosis factor (TNF) and interferon-gamma (IFN-gamma] in vitro regulators of adult hemopoietic differentiation. Growth stimulators were analyzed under serum-deprived conditions whereas growth inhibitors were investigated in serum-supplemented culture. Formation of granulocyte-macrophage colonies from embryonic progenitors was induced by GM-CSF but inhibited by TNF and IFN-gamma. Early erythroid progenitors resemble adult erythroid burst-forming cells (BFU-E) in their sensitivity to Ep and TNF but differ in their lack of response to GM-CSF or other adult sources of burst-promoting activity, and absence of inhibition by IFN-gamma. IGF-1 promoted erythroid burst formation in the absence of insulin, but did not have Ep-like activity. These data indicate that embryonic and adult erythroid progenitors differ at least in terms of in vitro sensitivity to GM-CSF and IFN-gamma and suggest that different cellular response to control signals may underlie the differences observed in vivo between embryonic and adult hemopoiesis.

Cell Differentiation↗
PubMed1988

In vitro differentiation of human granulocyte/macrophage and erythroid progenitors: comparative analysis of the influence of recombinant human erythropoietin, G-CSF, GM-CSF, and IL-3 in serum-supplemented and serum-deprived cultures.

The effects of recombinant human erythropoietin (Ep), granulocyte/macrophage (GM) and granulocyte (G) colony-stimulating factors (CSF), and interleukin-3 (IL-3) on erythroid burst and GM colony growth have been studied in fetal bovine serum (FBS)-supplemented and FBS-deprived culture. Sources of progenitor cells were nonadherent or nonadherent T-lymphocyte-depleted marrow or peripheral blood cells from normal humans. G-CSF, in concentrations up to 2.3 X 10(-10) mol/L, induced only the formation of neutrophil colonies. In contrast, GM-CSF and IL-3 both induced GM colonies and sustained the formation of erythroid bursts in the presence of Ep. However, the activities of these growth factors were affected by the culture conditions. IL-3 induction of GM colonies depended on the presence of FBS, whereas the degree of GM-CSF induction of GM colonies in FBS-deprived cultures depended on the method by which adherent cells were removed. GM-CSF increased colony numbers in a concentration-dependent manner only if the cells had been prepared by overnight adherence. Both GM-CSF and IL-3 exhibited erythroid burst-promoting activity in FBS-deprived cultures. However, some lineage restriction was evident because GM-CSF was two- to threefold more active than IL-3 in inducing GM colonies but IL-3 was two- to threefold more active in promoting erythroid burst growth. Furthermore, in FBS-deprived cultures, the number of both erythroid bursts and GM colonies reached the maximum only when Ep, GM-CSF, and IL-3 or GM-CSF, IL-3, and G-CSF, respectively, were added together. These results suggest that the colonies induced by IL-3, GM-CSF, and G-CSF are derived from different progenitors.

Bone Marrow Cells↗
PubMed1988

Effect of recombinant hematopoietic growth factors on proliferation of human marrow progenitor cells in serum-deprived liquid culture.

We investigated the effects of recombinant interleukin-3 (IL-3), granulocyte-macrophage and granulocyte colony-stimulating factors (GM-CSF and G-CSF), and erythropoietin (Ep) on the number of human hematopoietic progenitors after two to ten days of incubation in liquid cultures deprived of fetal bovine serum (FBS). The source of progenitor cells was normal human marrow depleted of T lymphocytes and/or adherent cells. When adherent cell-depleted marrow was cultured without growth factors, the number of progenitor cells was relatively constant for periods up to eight days. In contrast, a progressive decline in the number of progenitor cells was detected in cultures of nonadherent, T-cell-depleted marrow cells. In both cases, the addition of IL-3 increased by two- to fourfold over input the number of erythroid burst-forming cells (BFU-E) per culture. The number of BFU-E peaked either at day 4 or 8. G-CSF had no effect on the number of progenitor cells per culture. GM-CSF and Ep had no effect in cultures of nonadherent marrow cells but maintained the number of BFU-E in cultures of nonadherent, T-cell-depleted marrow cells. The addition of a neutralizing anti-GM-CSF monoclonal antibody, but not anti-IL-3 neutralizing antiserum, decreased the number of BFU-E in cultures of nonadherent marrow cells. None of the growth factors investigated enhanced the number of GM progenitors to the same degree as the number of BFU-E. However, in cultures of nonadherent, T-cell-depleted marrow cells, IL-3 and GM-CSF maintained the number of GM progenitors up to eight days. These results indicate that IL-3 alone is capable of increasing the number of BFU-E and of maintaining the number of GM progenitors in liquid culture, whereas GM-CSF and Ep are capable of maintaining, but not increasing, BFU-E in this system.

Blood Physiological Phenomena↗
PubMed1988

Synergism between erythropoietin and interleukin-3 in the induction of hematopoietic stem cell proliferation and erythroid burst colony formation.

The influence of recombinant erythropoietin (Ep) and interleukin-3 (IL-3) on the proliferation and differentiation of murine hematopoietic stem and progenitor cells was investigated in serum-deprived cultures. The differentiation of progenitor cells, purified by collecting blast cell colonies from spleen cell cultures of 5-fluorouracil-treated mice, was evaluated by scoring the number and type of colonies appearing after eight days in semisolid culture. IL-3 induced the formation of both erythroid and granulocyte-macrophage colonies in a concentration-dependent fashion, the plateau being reached at 300 U/mL. However, concentrations of IL-3 alone that had little or no effect (less than or equal to 10 U/mL) induced maximal numbers of erythroid bursts in the presence of Ep (1.5 IU/mL). In the presence of Ep alone, no colonies were seen. Proliferation of quiescent hematopoietic stem cells, purified by cell sorting and evaluated by spleen colony assay (CFU-S), was investigated by measuring the total cell number and CFU-S content and the DNA histogram at 20 and 48 hours of liquid culture. Almost no cells or CFU-S survived 20 hours of incubation without the addition of IL-3. The presence of either IL-3 (400 U/mL) or the combination of EP and IL-3 (10 U/mL), supported the maintenance of nearly 40% of sorted CFU-S for 48 hours. Approximately 10% of these cells were in the S phase of the cell cycle at 20 hours and an increase in the total cell number per culture, but not in the CFU-S content, was detected at 48 hours. These data indicate that IL-3 exerts a differentiative and proliferative effect on early stem and progenitor cells, which is concentration dependent. At IL-3 concentrations, which had little or no activity alone, Ep acted synergistically to induce both proliferation of stem cells and differentiation of erythroid progenitors.

Animals↗
PubMed1987

Regional distribution of Sindbis virus glycoproteins on the plasma membrane of infected baby hamster kidney cells.

Sindbis virus-infected baby hamster kidney (BHK) cells were analysed in surface replicas or conventional thin sections after specific immunolabelling with antiviral glycoprotein antibodies in conjunction with colloidal gold-conjugated protein A. Newly synthesized viral glycoproteins were detected, beginning 1 1/2 h after infection, while the virus maturation started 3 h after infection. The glycoproteins appeared to be inserted on the plasma membrane in large spots located mainly in the central area of the cells: no clustering of the labelling was detected. Later, the glycoproteins appeared to arrange linearly in regions in the medial portion of the cells. No labelling was found in the peripheral area or on the cell edges. A drastic change in the surface labelling was detected following the commencement of virus maturation: gold particles were organized mostly in small clusters, each labelling a budding virus. Very few glycoproteins appeared not to be involved in budding figures. The maturation of the virus was clearly regionalized, but during this time it also involved the peripheral area and the cell edges; preferential budding in narrow cellular processes was often observed. It appeared thus that either isolated glycoproteins soon after infection, or clustered glycoproteins at later times, are strictly regionalized on the plasma membrane: however, the early post-infection distribution is clearly different from that seen later during virus maturation. Our experiments support the concept of discrete plasma membrane domains even in cells that do not display distinct specialization of their surface.

Animals↗
PubMed1987

Free diffusion to and from the inner nuclear membrane of newly synthesized plasma membrane glycoproteins.

Sindbis virus-infected baby hamster kidney (BHK) cells were analyzed by thin section fracture-label. Specific immunolabel with antiviral glycoprotein antibodies was used in conjunction with colloidal gold-conjugated protein A. As we previously reported (Torrisi, M. R., and S. Bonatti, 1985, J. Cell Biol., 101:1300-1306), Sindbis transmembrane glycoproteins are present in the inner nuclear membrane as well as in the outer nuclear membrane, endoplasmic reticulum, Golgi stacks and vesicles, and plasma membranes. Viral glycoproteins located on the inner nuclear membrane resemble those present on the outer membrane in terms of amount, distribution, and preferential partition after fracture. We show in this paper that Sindbis glycoproteins after treatment with cycloheximide are removed from the inner nuclear membrane with the same kinetics as their counterparts present on the outer membrane. This finding strongly suggests that newly synthesized transmembrane glycoproteins may freely diffuse to and from the inner nuclear membrane before entering into the intracellular transport pathway to the plasma membrane.

Animals↗
PubMed1987

Cloning of human erythroid progenitors (BFU-E) in the absence of fetal bovine serum.

We describe culture conditions which enabled us to clone early human erythroid progenitors (BFU-E) in the absence of fetal bovine serum (FBS). Our medium, which is chemically fully defined, supports proliferation and differentiation of erythroid progenitors comparable to that in FBS-supplemented cultures. Furthermore, it allows cloning of BFU-E from all human haemopoietic tissues (adult marrow, embryonic liver and yolk sac) and adult or perinatal blood. This system should facilitate the investigation of human erythroid differentiation in vitro (e.g. cell-cell interaction, mechanism of action of haemopoietins and inhibitors, regulation of Hb synthesis) as well as the mechanisms underlying myeloproliferative disorders. As an example, we have found that recombinant Ep shows, in this culture system, the same dose response as Ep from conventional sources.

Adult↗
PubMed1987

Early hemopoietic differentiation: the action of multi-CSF is complemented by lineage specific growth factors.

Although mechanisms controlling differentiation of hemopoietic stem and early progenitor cells are still poorly understood, it is generally conceded that a pivotal role is played by hemopoietic growth factors (HGFs). However, in-vitro analysis of their action on early progenitors may be obscured by cell-cell interaction, as well as by the presence of fetal bovine serum (FBS). To overcome these limitations, we investigated the action of pure multipotent or lineage-specific HGFs on purified progenitors grown in FBS-free cultures. In the murine system, highly purified progenitors were cultured in the presence of multipotent colony-stimulating factor (multi-CSF, also termed interleukin-3), erythropoietin (Ep) and macrophagic-CSF (M-CSF). Each HGF was unable by itself to induce significant colony growth. However, combined addition of multi-CSF and either Ep or M-CSF gave rise only to pure erythroid or macrophagic colonies, respectively. Partly purified human progenitors were challenged by human granulomonocytic-CSF (GM-CSF), pluripotent CSF (PPO, also termed granulocytic-CSF, G-CSF) and Ep. Here again, each HGF was unable per se to promote colony growth, but combined addition of GM-CSF or PPO and Ep gave rise only to pure erythroid colonies. These results support a model of early hemopoietic differentiation according to which multi-lineage HGFs represent "competence" GFs, the action of which is complemented by lineage-specific "progression" HGFs.

Adult↗
PubMed1987

Evidence for direct action of human biosynthetic (recombinant) GM-CSF on erythroid progenitors in serum-free culture.

The biologic activity of human biosynthetic granulocyte-monocyte colony stimulating factor (GM-CSF) was investigated in serum-free culture of erythroid progenitors derived from adult peripheral blood. The morphology of erythroid bursts and the cloning efficiency of BFU-E under serum-free conditions were similar to those observed in dishes with fetal bovine serum (FBS). For these experiments, progenitor cells were partially purified by Ficoll-Paque density centrifugation, adherence to a plastic surface, and complement-mediated cytotoxicity of Leu-1+ elements. For some studies, blastlike cells were harvested directly from 6-day-old semisolid cultures. In serum-free culture of the light-density cell fraction, biosynthetic erythropoietin (Ep) was sufficient for formation of pure and mixed erythroid colonies whereas GM-CSF was required for granulocyte-monocytic colonies. When adherent and Leu-1+ cells were removed, or when in vitro differentiated blast cells were used as a source of progenitors, neither Ep or GM-CSF alone induced colony formation. In dishes supplemented with both growth factors, erythroid bursts were detected. Although the presence of GM-CSF alone did not induce formation of any colony or clusters, BFU-E were recorded when Ep was added 8 days later, suggesting that BFU-E could be maintained. Terminal maturation of the resulting erythroid bursts was delayed by 8 days. These results provide evidence that GM-CSF acts directly on early erythroid progenitors. Furthermore, they suggest that both Ep and GM-CSF are necessary to start the differentiation process.

Adult↗
PubMed1986

Human embryonic hemopoiesis. Kinetics of progenitors and precursors underlying the yolk sac----liver transition.

Human embryonic development involves transition from yolk sac (YS) to liver (L) hemopoiesis. We report the identification of pluripotent, erythroid, and granulo-macrophage progenitors in YS, L, and blood from human embryos. Furthermore, comprehensive studies are presented on the number of hemopoietic progenitors and precursors, as well as of other cell types, in YS, L, and blood at precisely sequential stages in embryos and early fetuses (i.e., at 4.5-8 wk and 9-10 wk postconception, respectively). Our results provide circumstantial support to a monoclonal hypothesis for human embryonic hemopoiesis, based on migration of stem and early progenitor cells from a generation site (YS) to a colonization site (L) via circulating blood. The YS----L transition is associated with development of the differentiation program in proliferating stem cells: their erythroid progeny shows, therefore, parallel switches of multiple parameters, e.g., morphology (megaloblasts----macrocytes) and globin expression (zeta----alpha, epsilon----gamma).

Colony-Forming Units Assay↗
PubMed1986

Bromodeoxyuridine treatment of normal adult erythroid colonies: an in vitro model for reactivation of human fetal globin genes.

We report that bromodeoxyuridine (BrdU) addition in semi-solid cultures of normal adult erythroid progenitors causes a sharp rise of gamma-globin gene expression in erythroid colonies. Control studies were carefully carried out to exclude the possibility of toxic effects exerted by the drug in these experimental conditions. In particular, BrdU addition induces a sharp increase in the level of relative gamma-globin synthesis and content in pooled BFU-E-derived colonies: this rise is clearly observed in single bursts of the mature type (largely composed of late erythroblasts) but not in immature ones (essentially comprising early erythroblasts). Furthermore, it is associated with an increase of the G gamma/G gamma + A gamma synthetic ratio from adult up to fetal like values. Reactivation of gamma-synthesis was observed even if BrdU was added to colonies composed essentially of early erythroblasts, ie, when BrdU was added to either bursts at day 10 of culture or late CFU-E-derived clones at day 1. These in vitro observations indicate modulation of gamma-synthesis at the stage of erythroblasts from normal adults. At the molecular level we suggest that BrdU, by replacing thymidine in DNA, may inhibit the switch from a fetal-like biosynthetic program expressed in early erythroblastic differentiation to the adult program expressed in later stages of maturation.

Azacitidine↗
PubMed1985

mRNA activity of a Sindbis virus defective-interfering RNA.

We obtained Sindbis defective-interfering particles by nine and undiluted passages of standard virus on chicken embryo fibroblasts. These particles contain a deleted 20S RNA molecule which has mRNA activity, as shown by translation in cell-free systems in vitro. In infected cells, this mRNA activity appeared to be totally inhibited except at very late times postinfection.

Defective Viruses↗