Modulation of the epidermal growth factor receptor of mouse embryonic palatal mesenchyme cells in vitro by growth factors

• Published in: The International journal of developmental biology Vol. 36; no. 2; pp. 275 - 282
• Main Authors: SHARPE, P. M, BRUNET, C. L, FERGUSON, M. W. J
• Format: Journal Article
• Language: English
• Published: Bilbao University of the Basque Country Press 01-06-1992
• Subjects: Animals; Binding Sites; Biological and medical sciences; Cells, Cultured; Embryology: invertebrates and vertebrates. Teratology; Epidermal Growth Factor - metabolism; Fibroblast Growth Factor 2 - antagonists & inhibitors; Fibroblast Growth Factor 2 - pharmacology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Insulin-Like Growth Factor II - pharmacology; Mesoderm - metabolism; Mice; Organogenesis. Fetal development; Organogenesis. Physiological fonctions; Palate - embryology; Palate - metabolism; Receptor, Epidermal Growth Factor - drug effects; Temperature; Transforming Growth Factor beta - pharmacology; Embryonic development; Vertebrata; Embryo; Mammalia; Epidermal growth factor; Mouse; Rodentia; Mesenchyma; Palate; Growth factor; Biological receptor
• ISSN: 0214-6282; 1696-3547

A single class of high-affinity receptors for EGF were detected on mouse embryonic palatal mesenchyme (MEPM) cells cultured in vitro. The degree of confluence of the cultured cells did not affect the number or affinity of the binding sites. Culture of MEPM cells in the presence of bFGF, IGF-II or TGF-beta 1 induced changes in 125I-EGF binding. TGF-beta 1 caused a marked reduction in binding to 40% of control levels. This reduction was achieved after 2 h and persisted for 24 h after addition of the growth factor. IGF-II induced a similar reduction but this effect was transitory; after a 12 h pretreatment with IGF-II, binding was restored to control levels. The effects of bFGF were biphasic. Initially, a short pre-treatment period (3-5 h) with bFGF caused a small reduction in 125I-EGF binding; longer periods of pre-incubation (24 h) resulted in a large increase in receptor number. Pre-incubation in medium containing both bFGF and TGF-beta 1 resulted in a decrease in EGF binding. Thus, TGF-beta 1 negated the large increase in receptor number induced by bFGF alone. Changes in receptor number were usually, but not always, directly related to changes in the biological activity of EGF, as assessed by a thymidine incorporation assay. This study highlights the possible interactive role of growth factors known to be present in the developing palate.