ISSN:0897-7194    

DOI:10.3109/08977199308991577

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractWhen human cytotrophoblastic cells in the early stage of pregnancy were cultured in a serum-free medium in the presence of human macrophage colony-stimulating factor (M-CSF), the cytotrophoblastic cells fused and formed a typical syncytiotrophoblast which had a dense distribution of microvilli revealed under an electron microscope. On the other hand, cytotrophoblasts incubated with anti-M-CSF antibody showed hardly any syncytiotrophoblast formation.Following this finding, we studied the differentiation of chorionic cells from the viewpoint of hormone secretion. When cytotrophoblasts were incubated in the presence of M-CSF, the supernatant of the culture showed an increase in human chorionic gonadotropin and human placental lactogen levels in proportion to the concentration of M-CSF added. When cytotrophoblasts were incubated in the presence of anti-M-CSF antibody or anti-fms antibody, human chorionic gonadotropin and human placental lactogen secretion were suppressed. Thus, M-CSF was morphologically and endocrinologically found to induce the differentiation of chorionic cells.

ISSN:0897-7194    

DOI:10.3109/08977199308991578

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractWe have examined the role ofGiαin haemopoietic cells using the myelomonocytic progenitor cell lines FDC-P1 and WEHI-3B (JCS). During growth factor-dependent proliferation of FDC-PI cells GIαwas found predominantly in the nucleus and associated with the plasma membrane. Following removal of growth factor,Giαaccumulated in the cytoplasm and at the plasma membrane. Treatment of FDC-PI cells with pertussis toxin (PT) completely inhibited translocation ofGiαto the nucleus and reduced the sensitivity of FDC-P1 cells to the proliferative effects of growth factors, indicating that translocalion ofGiαplays a regulatory role in, but may not be essential for, cell division. Giαinitially associated with DNA during S/G2 of the FDC-P1 cell cycle but separated from condensing chromosomes during mitosis. In contrast to FDC-P1 cells, WEHI-3B (JCS) cells proliferate in the absence of added growth factors but can be induced to differentiate by TNF-α. In proliferating JCS cells Giαwas again associated with the nucleus but when proliferation was inhibited by TNF-α, Giαaccumulated in the cytoplasm with none detected in the nucleus. Thus the cytokine regulated accumulation ofGiαat different intracellular sites correlated with the ability of the cell to progress through the proliferative cycle. When the tyrosine kinase inhibitor genistein was added to FDC-P1 cells prior to stimulation with IL-3 or GM-CSF, proliferation was almost completely inhibited but translocation ofGiαwas not affected, suggesting that tyrosine phosphorylation was not involved in G protein translocation but was essential for cytokine induced cell division. Cholera toxin (CT) also inhibited proliferation of FDC-P1 cells but had no effect on translocation ofGiαto the nucleus. The near complete inhibition of cell division by genistein and CT without a corresponding effect on Giαmovement indicates that Giαcan be regulated independently of tyrosine kinase and adenylyl cyclase activities, respectively.

ISSN:0897-7194    

DOI:10.3109/08977199308991579

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractWhen granulocyte-macrophage colony-stimulating factor (GM-CSF) is chemically conjugated to the ribosome-inactivating protein saporin, the resulting protein conjugate is highly toxic for cells expressing the GM-CSF receptor. Structural and Western blot analyses of the purified conjugate establish that it contains equimolar amounts of the starting materials and is free of any contamination by the non-conjugated components. The resulting bifunctional reagent is specifically cytotoxic to cells expressing the GM-CSF receptor, but is ineffective to cells that do not express the receptor. The cytotoxic activity is inhibited in a dose-dependent manner by GM-CSF, but not by any one of five other peptide growth factors. This is the first report of a mitotoxin for cells that express the GM-CSF receptor and which promises to be a valuable tool to study the expression of the GM-CSF receptor in normal and pathological states.

ISSN:0897-7194    

DOI:10.3109/08977199308991580

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractTo measure the effect of endogenous IL-3 (Multi-CSF) expression on hematopoietic cellsin vivo, we have infected several kinds of hematopoietic cell populations with retroviral vectors carrying the IL-3 gene (M3MuV)in vitroand injected the virus-producing cells into mice to“target”the virus to sites of hematopoiesis. Mast cell lines (Elut cells) or multipotent cell lines (FDC-Pmix) were infected with MPSV-based replication defective retroviral vectors carrying either the neomycin resistance gene alone (M3neoV) or the neomycin gene plus the IL-3 gene (M3MuV). These cell lines produced infective retroviral particles consisting of the replication defective vectors and helper virus constitutively produced by the target cell populations. Irradiated and non-irradiated virus-producing Elut cells and the virus-producing FDC-Pmix cells were transplanted into syngeneic mice to“target”virus infection to the sites of hemopoiesis. Control mice injected with M3neoV-producing cells did not develop a disease up to 6 months following transplantation, whereas mice injected with M3MuV-producing cells developed a myeloproliferative disease within 3 months. Hematopoietic cell lines were rescued from diseased and control mice. In all cases these cell lines were of host origin. Cell lines derived from control mice were of basophil/mast cell morphology only, and required IL-3 for their continued proliferation (similar to cell lines derived from uninfected animals), whereas the cell lines generated from spleen and bone marrow cells of host mice with myeloproliferative disease carried the M3MuV vector, were G418 resistant and IL-3 independent. The biologic properties of M3MuV infected host derived cell lines varied considerably. Some were multipotential and could be induced to differentiate in response to stromal cells and serum factors, others were more restricted to the granulocyte/macrophage lineage but were also differentiation inducible, and some were blocked in differentiation at the myeloblast/promyelocyte stage. We conclude that the injected donor cells acted as“infectious centers”to facilitate the infection of host hematopoietic cells with the M3MuV vector. Our results indicate that the“targeted”in vivoinfection of primitive hematopoietic cells with M3MuV can initiate the immortalization and leukaemogenesis of multipotential and lineage restricted progenitor cells.

ISSN:0897-7194    

DOI:10.3109/08977199308991581

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractC3H10T1/2 cells are an established mesenchymal stem cell line which can differentiate into muscle, fat and cartilage cells when treated with azacytidine. Bone morphogenetic protein-2 (BMP-2) caused a dose dependent differentiation of these cells into fat, cartilage and bone cells—low concentrations favoring adipocytes and high concentrations chondrocytes and osteoblasts. The differentiated phenotypes were stable in the absence of BMP-2. Furthermore, the addition of other growth factors during the differentiation process altered the frequency of the differentiated colony formation. Transfection of the C3H10T1/2 cells with a BMP-2 cDNA also induced a phenotypic change from the parental fibroblast to adipocytes and osteoblasts. Our results in this model system indicate that a single protein factor can cause differentiation of a stem cell line to multiple phenotypes, that phenotypes induced can be regulated by factor concentration, and that other factors can also influence BMP-2 induced differentiation.

ISSN:0897-7194    

DOI:10.3109/08977199308991582

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractIntravenous administration of human basic fibroblast growth factor (bFGF) for 2 weeks stimulated osteoblast proliferation and new bone formation in various skeletal bones in young and aged rats at dosage levels of 0.1 mg/kg/day and greater. Morphometry of the soft X-ray radiograms of cross sections of the tibia indicated about a 20% increase in the calcified bone area of the diaphysis at 0.1 mg/kg/day. The Ca and hydroxyproline contents showed statistically significant increases at this dosage. The new bone formation was found only on the endosteal side, and no periosteal bone formation was found. Similar systemic osteogenic potential was seen after intravenous administration of other growth factors of the FGF family, human acidic FGF and human heparin-binding secretory transforming protein-1. The above results suggest a potential therapeutic role for these growth factors in bone-loss diseases such as osteoporosis.

ISSN:0897-7194    

DOI:10.3109/08977199308991583

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractTreatment of quiescent cultures of mouse embryo-derived AKR-2B cells with transforming growth factorβresulted in an induction of basic fibroblast growth factor (bFGF) mRNA and bFGF protein in the stimulated cells. In contrast to bFGF, acidic fibroblast growth factor (aFGF) was not induced by TGFβ. The mitogenic effect of transforming growth factorβon AKR-2B cells may be mediated by the induction of bFCF in these cells.

ISSN:0897-7194    

DOI:10.3109/08977199308991584

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor