摘要:

AbstractThe localization of acidic fibroblast growth factor (aFGF) in the male mouse brain was studied with biochemical and immunocytochemical techniques. Using two peptide-based aFGF antisera directed against independent epitopes, Western gel analysis of dissected brain demonstrated significant levels of aFGF immunoreactivity in the pons-medulla, hypothalamus and cerebellum. The cortex contained much less immunoreactivity. Consistent with the biochemical data, immunocytochemical analysis with the same two antisera demonstrated that aFGF immunoreactivity is localized in neuronal cell bodies in these regions. Numerous immunoreactive neurons were observed in the reticular formation of the pons and medulla, as well as in several other brainstem nuclei and areas. Immunoreactive neurons were also present in the lateral and medial hypothalamus, and some thalamic, subthalamic and epithalamic nuclei. In the basal ganglia, immunoreactive neurons were present in the amygdala and septum. Few intensely stained immunoreactive neurons were observed in the striatum, pallidum and neocortex. Limbic cortices contained more numerous immunoreactive neurons than neocortex. These results support the concept that aFGF is present in the brain, where it is heterogeneously distributed in neuronal cell bodies in regions involved in sensory, extrapyramidal motor, limbic and autonomic functions. The results are consistent with various neurotrophic, autogenic, and neuromodulatory functions associated with aFGF in the mammalian central nervous system.

ISSN:0897-7194    

DOI:10.3109/08977199209021528

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractPreviously we reported that,in vitro, lens cells proliferate, migrate or differentiate in response to low, medium and high concentrations of FGF respectively. To examine further the role of FGF in lens development we used immunohistochemistry to study the distribution of aFGF and bFGF in the eye of the 20 day rat foetus. Strong aFGF-like reactivity was localised in a band of cells near the lens equator which included the germinative zone where most cell proliferation occurs and the transitional zone where epithelial cells differentiate into fibres. The closely apposed inner epithelial layer of the ciliary and iridial retina also reacted strongly. Reactivity for aFGF was also found in the epidermis and in the corneal and conjunctival epithelia. In the neural retina, reactivity was found in the nerve fibre layer and in isolated cells of the inner plexiform layer. bFGF-like reactivity was found in the retinal ganglion cell layer, extra-ocular muscles and associated with endothelial cells of the hyaloid, lenticular and choroid vasculatures. Pre-digestion of sections with hyaluronidase caused loss of cell-associated reactivity but revealed strong bFGF-like reactivity in ocular basement membranes, in particular, the lens capsule. The sensitivity of this capsular bFGF localisation to heparinase indicates that bFGF in the extracellular matrix is complexed with heparan sulphate proteoglycans. The results of this study are consistent with the hypothesis that FGF plays an important role in lens development via both autocrine and paracrine mechanisms.

ISSN:0897-7194    

DOI:10.3109/08977199209021529

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0897-7194    

DOI:10.3109/08977199209021530

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0897-7194    

DOI:10.3109/08977199209021531

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractThe effect of three different isoforms of transforming growth factor-β(TGF-β) on the expression of TGF-β2 mRNA was studied in several continuous tumor cell lines. As previously reported for the mouse fibroblast cell line AKR-2B, the expression of TGF-β2 mRNA transcripts of 5.4, 4.7, 3.7 and 3.0 kb was decreased after a 24 hr treatment with 5ng/ml of TGF-β1, TGF-β2 or TGF-β3. In A549, HBL-100 and BSC-1 epithelial cell lines, five distinct TGF-β2 mRNA transcripts of 5.8, 5.1, 4.0, 3.8 and 2.8 kb were detected by Northern blot analysis. Treatment of these cells with TGF-β1, TGF-β2 or TGF-β3 for 24 hr resulted in a 2–3 fold increase in the 5.8, 4.0 and 3.8 kb transcripts, with little detectable change in abundance of the 5.1 and 2.8 kb transcripts. The effect of the TGF-βproteins was dose (5 ng/ml) and time (3–6 hr) dependent. A similar 2–3 fold increase in the level of secreted TGF-β2 was observed following treatment of A549 cells with TGF-β1. Basal level and induced expression of TGF-β2 mRNA in response to TGF-βisoforms was decreased in the presence of actinomycin D. In all cell lines studied, the expression of the 2.5 kb TGF-β1 mRNA was relatively unchanged or markedly increased in response to treatment with TGF-β. These studies support the hypothesis that expression of TGF-β2 is regulated by members of the TGF-βfamily and is dependent upon cell type.

ISSN:0897-7194    

DOI:10.3109/08977199209021532

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractUsing inununohistochemical methods we have investigated the presence of transforming growth factorsβ1,β2 andβ1 precursor in a two-week-old trilaminar human embryo. TGF-β1 precursor was seen in both the epiblast and the hypoblast. In contrast to the widespread localization of TGF-β1 precursor in the embryo proper, antibodies to the mature TGF-β1 peptide localized preferentially to the hypoblast with only weak staining in the epiblast. Staining with antibodies to TGF-β2 was generally weak in both the epiblast and hypoblast layers of the embryo proper. These results show that TGF-β1 andβ2 peptides are detectable as early as the second week of human development.

ISSN:0897-7194    

DOI:10.3109/08977199209021533

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractWe have isolated and sequenced a cDNA (mrfms) encoding ratc-fmsgene (CSF-1 receptor) from proliferating L6α1 myoblasts. The predicted amino acid sequence was highly identical with thec-fmsprotein found in monocytes and macrophages (98, 76 and 84% identity from mouse, cat and humanc-fmsproteins, respectively). The mechanisms responsible for the regulation of mrfms gene expression during myogenesis were examined. Mrfms products were observed during proliferation of L6α1 myoblasts and were downregulated during differentiation. Run-on transcription assays demonstrated that the mrfms gene was transcriptionally active only in undifferentiated myoblasts. These findings suggested that mrfms levels in L6α1 myoblasts are controlled by transcriptional mechanisms. The half-life of mrfms transcripts was found to be at least 5 hr while inhibition of protein synthesis with cycloheximide (CHX) decreased this half-life to 30 min without changes in the rate of mrfms gene transcription. In addition oncogenic transformation of L6al myoblasts by thev-frnsinduced constitutive upregulation of mrfms mRNAs, and nuclear run-on assays demonstrated that mrfms transcription was not growth-factor dependent. Furthermore, these findings with others previously published indicate that mrfms gene products may play a role in the normal and neoplastic growth of muscular cells.

ISSN:0897-7194    

DOI:10.3109/08977199209021534

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractIn order to explain the high proliferative potential of human placental cytotrophoblasts, we have addressed the potential involvement of platelet-derived growth factor (PDGF) ligand and receptors. Although PDGF is usually described as a mitogen for cells of mesenchymal origin, we show in this report that extra-villous term placental cytotrophoblasts express the PDGFα-andβ-receptor genes, bothin vivoandin vitro. In addition, cytotrophoblasts produce significant amounts of PDGF-B protein. By immunohistochemical analysisof receptor expression, we found that the PDGF a-receptors could be detected at the cell surface, while the PDGFβ-receptors were only detected inrracellularly. In addition, double immunostaining analysisshowed that the PDGFα-andβ-receptor molecules are expressed in different subpopulations of cytotrophoblasts. The addition of PDGF-AA and PDGF-BB homodimers to cytotrophoblast primary cultures induced a significant increase in DNA synthesis. We conclude, therefore, that PDGF is a growth factor for placental cytotrophoblasts and suggest that the growth of cytotrophoblasts can partly be explained by a PDGF autostimulatory loop, limited by the number of receptor-positive cytotrophoblasts.

ISSN:0897-7194    

DOI:10.3109/08977199209021535

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractContinuous proliferation of the immortalized myeloid progenitor cell line FDC-P1 depends on stimulation with either interleukin-3 (IL-3) or granulocyte-macrophage colony stimulating factor (GM-CSF). Two other cytokines, interferon-γ(IFN-γ) and IL-4, were found to prolong FDC-P1 survival for several days. Surviving cells incorporated [3H]thymidine and a minority completed up to 3 cell divisions before dying. This transient proliferative response was a direct effect of IFN-γand IL-4 since these cytokines did not induce production of detectable IL-3 or GM-CSF and the response was unaffected by cell concentration. IL-6, a constitutive product of FDC-P1 cells whose secretion was increased by IL-3, GM-CSF and IL-4 but not by IFN-γ, was not responsible for the proliferative response. FDC-P1 lines that constirutively expressed the cell cycle-associated oncogenemycor the survival-associated oncogenebcl-2also responded only transiently to IFN-γor IL-4, indicating that expression of these genes did not complement the signals delivered by IFN-γor IL-4. By contrast, the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) prolonged survival of FDC-P1 cells on its own and potentiated the response to IFN-γor IL-4, although the combination of stimuli did not support long-term growth. It is concluded that IFN-γand IL-4 trigger only some of the signalling events that lead to mitogenesis; these events are complemented by stimulation with PMA but additional signals are required for sustained proliferation.

ISSN:0897-7194    

DOI:10.3109/08977199209021536

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractEpidermal growth factor (EGF) stimulates the mitosis and differentiation of a variety of cellular types. It also delays the cell senescencein vitro. Because of its multiple functions, the effects of EGF on cells from isolated, explanted calf renal glomeruli have been studied. The cell types emerging from glomeruli cultured with and without EGF were compared and identified by morphological, immunofluorescence and electron microscopy criteria. Two cell types: visceral epithelial cells or podocytes (type I) and mesangial cells (type II) emerged from glomeruli cultivated without EGF. A third cell type, called type III cells, appeared only in the presence of EGF. These cells divided, were mobile and had prolonged lifespan in culture. They appeared pavement-like, and acquired progressively the morphological features and cytoskeletal components of type I cells. They also showed certain characteristics of podocytesin vivo. We suggest that type III epithelial-like cells are precursor cells of podocytes, that EGF triggers their emergence from glomeruli and their subsequent proliferation and differentiationin vitro. EGF also prolongs their lifetime in culture.

ISSN:0897-7194    

DOI:10.3109/08977199209021537

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor