epidermal-growth-factor and Graves-Disease

Topics: Adult; Aged; Aging; Alcoholism; Amino Acids; Anesthetics, Local; Animals; Anti-Infective Agents; Anti-Inflammatory Agents; Aqueous Humor; Autonomic Nervous System; Biological Transport, Active; Brain Chemistry; Cardiac Glycosides; Catecholamines; Cell Differentiation; Central Nervous System; Diabetes Mellitus, Type 1; Diabetic Retinopathy; Epidermal Growth Factor; Eye; Fibrinolysis; Glaucoma; Granuloma; Graves Disease; Hallucinogens; Humans; Hypertension; Immunity, Cellular; Infant; Infant, Newborn; Leukotriene B4; Metabolism, Inborn Errors; Multiple Sclerosis; Muscle Relaxation; Nutritional Physiological Phenomena; Oxygen; Oxygen Consumption; Pigment Epithelium of Eye; Pineal Gland; Prostaglandin Antagonists; Prostaglandins; Psychotropic Drugs; Retina; Retinal Degeneration; Serotonin; Smoking; SRS-A; Stress, Physiological; Water-Electrolyte Balance

We observed amino acid homology between the cysteine-rich N terminus of the thyrotropin receptor (TSHR) ectodomain and epidermal growth factor-like repeats in the laminin gamma1 chain. Thyroid-stimulating autoantibodies (TSAb), the cause of Graves' disease, interact with this region of the TSHR in a manner critically dependent on antigen conformation. We studied the role of the cluster of four cysteine (Cys) residues in this region of the TSHR on the functional response to TSAb in Graves' patients' sera. As a benchmark we also studied TSH binding and action. Removal in various permutations of the four cysteines at TSHR positions 24, 29, 31, and 41 (signal peptide residues are 1-21) revealed Cys(41) to be the key residue for receptor expression. Forced pairing of Cys(41) with any one of the three upstream Cys residues was necessary for trafficking to the cell surface of a TSHR with high affinity TSH binding similar to the wild-type receptor. However, for a full biological response to TSAb, forced pairing of Cys(41) with Cys(29) or with Cys(31), but not with Cys(24), retained functional activity comparable with the wild-type TSHR. These data suggest that an N-terminal disulfide-bonded loop between Cys(41) and Cys(29) or its close neighbor Cys(31) comprises, in part, the highly conformational epitope for TSAb at the critical N terminus of the TSHR. Amino acid homology, as well as cysteine pairing similar to the laminin gamma1 chain epidermal growth factor-like repeat 11, suggests conformational similarity between the two molecules and raises the possibility of molecular mimicry in the pathogenesis of Graves' disease.

Topics: Amino Acid Sequence; Animals; Autoantibodies; CHO Cells; Cricetinae; Disulfides; Epidermal Growth Factor; Graves Disease; Humans; Laminin; Molecular Sequence Data; Receptors, Thyrotropin; Sequence Homology, Amino Acid

Epidermal growth factor (EGF) has widespread growth effects, and in some tissues proliferation is associated with the nuclear localization of EGF and epidermal growth factor receptor (EGFR). In the thyroid, EGF promotes growth but differs from thyrotropin (TSH) in inhibiting rather than stimulating functional parameters. We have therefore studied the occurrence and cellular distribution of EGF and EGFR in normal thyroid, in Graves' disease, where growth is mediated through the thyrotropin receptor (TSHR), and in a variety of human thyroid tumors. In the normal gland the staining was variable, but largely cytoplasmic, for both EGF and EGFR. In Graves' disease there was strong cytoplasmic staining for both EGF and EGFR, with frequent positive nuclei. Nuclear positivity for EGF and particularly for EGFR was also a feature of both follicular adenomas and follicular carcinomas. Interestingly, nuclear staining was almost absent in papillary carcinomas. These findings document for the first time the presence of nuclear EGF and EGFR in thyroid. Their predominant occurrence in tissues with increased growth (Graves' disease, follicular adenoma, and carcinoma) may indicate that nuclear EGF and EGFR play a role in growth regulation in these conditions. The absence of nuclear EGF and EGFR in papillary carcinomas would suggest that the role played by EGF in growth control differs between papillary carcinoma and follicular adenomas/carcinomas of the thyroid.

Topics: Adenoma; Carcinoma; Carcinoma, Papillary; Cell Nucleus; Epidermal Growth Factor; ErbB Receptors; Goiter, Nodular; Graves Disease; Humans; Immunohistochemistry; Reference Values; Thyroid Gland; Thyroid Neoplasms; Tissue Distribution

We evaluated the concentration of epidermal growth factor (EGF) in platelets, serum and plasma obtained from 47 patients with Graves' disease, 7 with hypothyroidism and 20 healthy subjects. The platelets of the subjects were collected from platelet rich plasma and lysed by freezing and thawing. Subsequently the platelet debris was treated with Triton X-100. The EGF concentration was determined by homologous radioimmunoassay. The concentration of EGF in the platelets in 14 patients with untreated Graves' disease was significantly higher than that in the healthy controls. After treating these 14 patients with antithyroid agents, the EGF concentration in the platelets decreased to the level of the healthy controls. The EGF concentration in the platelets in the 7 untreated hypothyroid patients decreased after replacement therapy with thyroxine. The mean volume of the platelets in the 14 patients with untreated Graves' disease was significantly larger than in the control and decreased after treatment with antithyroid agents. The serum and plasma levels of EGF in the 7 untreated hypothyroid increased after replacement therapy. In conclusion, thyroid function affected the concentration of EGF in the platelets of patients with thyroid disorders.

Topics: Adult; Blood Platelets; Epidermal Growth Factor; Female; Graves Disease; Humans; Hypothyroidism; Male; Methimazole; Middle Aged; Platelet Count; Propylthiouracil; Thyroid Diseases; Thyroxine

A stimulation of thyroid epithelial cell proliferation by epidermal growth factor (EGF) has been repeatedly reported in different in vitro systems. Furthermore, a suppression of thyroid epithelial cell function by EGF has been described in vitro. In order to investigate the effects of EGF on the thyroid in vivo, human Graves' disease tissue was transplanted to 59 nu/nu mice. EGF was given once, and over a period of 7 days 7 times intermittently or continuously by osmotic mini pumps to mice. 3-H-thymidine histoautoradiography of transplants showed an increased 3-H-thymidine incorporation of thyroid epithelial cells and mesenchymal cells, following each form of EGF application. Thyroid epithelial cell nuclear volume, which has previously been shown to be a parameter for thyroid epithelial cell function showed a decrease following EGF application. There was a tendency to a more intensive proliferation and differentiation following intermittent EGF application compared to continuous stimulation. These results demonstrate that EGF does stimulate proliferation of thyroid epithelial as well as mesenchymal cells in vivo. The growth stimulating effect of EGF is linked with a concomitant decrease of thyroid function in vivo. The latter is most likely due to the dedifferentiating action of EGF previously shown in in vitro systems.

Topics: Animals; Cell Division; Epidermal Growth Factor; Epithelial Cells; Epithelium; Graves Disease; Humans; Mice; Mice, Nude; Stimulation, Chemical; Thymidine; Thyroid Gland; Transplantation, Heterologous

To investigate the role of interleukins on the growth of human thyroid cells, the effect of IL-2, IL-4 and IL-6 was studied on EGF-induced [3H]-thymidine uptake, cell cycle by flow cytometry, and mRNA levels of cellular proto-oncogene c-fos in thyroid monolayer cells from eighteen patients with Graves' disease and sixteen with non-thyroidal disease. EGF stimulated the DNA synthesis and the expression of c-fos mRNA both in Graves' thyroid cells and in normal thyroid cells. A dose-dependent inhibition of Graves' thyroid cell growth was observed with increasing concentration of IL-2 regardless of coculture with EGF. IL-2 did not influence [3H]-thymidine uptake nor the percentage of S+G2/M phase in cell cycle in normal thyroid cells. Such effects were not modified by the elimination or addition of lymphocytes. IL-2 did not affect the EGF-induced expression of c-fos mRNA in both Graves' and normal thyroid cells. IL-6 (10(-2)-10 ng/ml) stimulated the [3H]-thymidine uptake up to 218-303 % of control level, and the percentage of cells in S+G2/M phase was increased in IL-6-treated normal thyroid cells as compared to EGF-treated cells. IL-6 did not augment these parameters in Graves' thyroid cells. When EGF was included with IL-6, the level in c-fos mRNA was further augmented in normal thyroid cells. Such an additive effect was not seen in Graves' thyroid cells. Incubation of Graves' or normal thyroid cells with IL-4 did not affect the [3H]-thymidine uptake nor the percentage of S+G2/M. These data suggest that, compared with normal cells, the growth factors (such as cytokines), may act in an opposite way in Graves' thyroid cells. The different behavior between Graves' and normal thyroid cells in response to IL-2 and IL-6 might contribute to the pathogenesis of goiter formation.

Topics: Cell Cycle; Cell Division; Cells, Cultured; DNA; Epidermal Growth Factor; Graves Disease; Humans; Interleukin-2; Interleukin-4; Interleukin-6; Proto-Oncogene Mas; Proto-Oncogene Proteins c-fos; Reference Values; RNA, Messenger; Stimulation, Chemical; Thyroid Gland

Monensin is a carboxylic ionophore which perturbs the structure and function of the Golgi apparatus and lysosomes. In the present study, we investigated the functional significance of these organelle in the growth factor-mediated cell proliferation in cultured human thyroid cells from normal and Graves' disease. DNA synthesis was estimated by [3H]-thymidine uptake and flow cytometric analysis. Monensin inhibited both [3H]-thymidine uptake in a dose-dependent manner and the transition of G1 to S phase determined by flow cytometric analysis. Monensin partially blocked the effect of bovine TSH in normal thyroid cells. [3H]-thymidine uptake was suppressed to 56.7 +/- 37.3% of the control value with bTSH and monensin, but it was still higher than those with monensin alone (21.9 +/- 15.0% of the control). The percentage of cells in the S phase was also increased from 7.64 +/- 1.91% with monensin alone to 11.54 +/- 2.82% with bTSH at t = 24h. Forskolin or 12-O-tetradecanoylphorbol 13-acetate (TPA) could not mimic the action of TSH. On the other hand, insulin and EGF most effectively counteracted monensin-induced inhibition of DNA synthesis in Graves' thyroid cells. [3H]-thymidine uptake was not completely inhibited, being 73.5 +/- 24.0% with EGF, 105.0 +/- 25.4% with insulin, and 49.2 +/- 6.6% with monensin alone, respectively. The percentage of cells in the S phase also increased from 8.31 +/- 2.61% with monensin alone to 11.25 +/- 4.27% with EGF and 12.86 +/- 3.12% with insulin. In conclusion, the functional maintenance of the Golgi apparatus and lysosomes is necessary for DNA synthesis in both normal and Graves' thyroid cells, in which bTSH, insulin, and EGF might be differently involved in the regulation of DNA synthesis.

Topics: Cell Cycle; Cells, Cultured; DNA; Endocytosis; Epidermal Growth Factor; Flow Cytometry; Golgi Apparatus; Graves Disease; Humans; Insulin; Lysosomes; Monensin; Signal Transduction; Tetradecanoylphorbol Acetate; Thymidine; Thyroid Gland; Thyrotropin

To determine whether serum immunoglobulin in addition to epidermal growth factor (EGF) augment growth in human thyroid cells, effects of these factors on thyrocytes were tested using IgG derived from 34 patients with Graves' disease and 12 normal subjects. The cell growth was estimated by [3H]-thymidine uptake, cell cycle determined by FACS analysis and the expression of c-fos mRNA in monolayer thyrocytes enzymatically prepared from Graves' thyroid. The addition of IgG taken from patients with Graves' disease inhibited the [3H]-thymidine uptake compared to that taken from control subjects. IgG taken from Graves' disease suppressed EGF-induced increase of S + G2/M phase in cell cycle and the expression of c-fos mRNA, while those taken from normal subjects did not affect at all. [3H]-thymidine uptake was more suppressed by IgG from patients with a smaller-sized goiter than by those with a larger-sized one. There was a negative correlation between the suppression of [3H]-thymidine uptake and levels of TBII (p less than 0.05). There was no correlation between the degree of suppression and the levels of T3, T4, TSAb, TSBAb or MCHA. Thus, in conclusion, IgG derived from sera of Graves' may inhibit the growth of Graves' thyrocytes, leading to the determination of the goiter size.

Topics: Chromatography, DEAE-Cellulose; Epidermal Growth Factor; Gene Expression; Genes, fos; Graves Disease; Humans; Immunoglobulin G; RNA, Messenger; Thymidine; Thyroglobulin; Thyroid Gland

We analyzed epidermal growth factor receptors (EGF-R) and the growth stimulatory effects of epidermal growth factor (EGF) in the presence or absence of TSH on cultured human non-neoplastic and Graves' thyroid cells. All cells studied possessed EGF-R composed of two components. There was no significant differences in the binding characters of EGF-R among non-neoplastic thyroid cells whether they were obtained from thyroid tissues adjacent to malignant carcinoma or benign adenoma. Ten nM of EGF stimulated (3H)-thymidine (dTR) incorporation of non-neoplastic thyroid cells by about 50%. However, TSH had no effect on the growth of these cells. Both EGF-R binding parameters and cell proliferation effects of EGF and TSH were simultaneously examined in non-neoplastic thyroid cells from 8 patients. A significant inverse correlation (r = -0.757) was observed between binding affinity (Ka1) and EGF-induced increase of dTR incorporation. Binding capacity (Cmax) did not correlate significantly with dTR incorporation. In Graves' thyroid cells, all parameters of EGF-R were significantly lower than those of non-neoplastic thyroid cells, higher basal dTR incorporation was observed, and their goiter size significantly correlated with EGF-induced increase of dTR incorporation (r = 0.879) and also appeared to correlate inversely with Ka1. These data indicate a close relationship between the binding affinity of EGF-R and thyroid cell growth.

Topics: Cell Division; Cells, Cultured; Epidermal Growth Factor; ErbB Receptors; Graves Disease; Humans; Thymidine; Thyroid Gland; Thyroid Neoplasms