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D Claisse

Publications and source records attributed to D Claisse.

9 recordsLinked to original sources
PubMed1999

Influence of transforming growth factor beta1 (TGF-beta1) on the behaviour of porcine thyroid epithelial cells in primary culture through thrombospondin-1 synthesis.

Transforming growth factor beta1 (TGF-beta1) is a secreted polypeptide that is thought to play a major role in the regulation of folliculogenesis and differentiation of thyroid cells. On porcine thyroid follicular cells cultured on plastic substratum, TGF-beta1, in a concentration-dependent way, promoted the disruption of follicles, cell spreading, migration and confluency by a mechanism that did not involve cell proliferation. TGF-beta1 strongly activated the production of thrombospondin-1 and (alpha)vbeta3 integrin in a concentration-dependent manner whereas the expression of thyroglobulin was unaffected. Anisomycin, an inhibitor of protein synthesis, inhibited the effect of TGF-beta1 on cell organization. Thrombospondin-1 reproduced the effect of TGF-beta1. In the presence of thrombospondin-1 cells did not organize in follicle-like structures but, in contrast, spreaded and reached confluency independently of cell proliferation. This effect is suppressed by an RGD-containing peptide. The adhesive properties of thrombospondin-1 for thyroid cells were shown to be mediated by both the amino-terminal heparin-binding domain and the RGD domain of thrombospondin-1. Adhesion was shown to involve (alpha)vbeta3 integrin. The results show that TGF-beta1 exerted an influence upon function and behaviour of follicle cells partly mediated by the synthesis of thrombospondin-1 and of its receptor (alpha)vbeta3 integrin.

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PubMed1996

In vivo modulation of annexins I, II and V expression by thyroxine and methylthiouracil.

Regulation of annexin concentration and localization were investigated in thyroid tissues of hypothyroid [methylthiouracil (MeSur) treatment], euthyroid (control) and hyperthyroid [thyroxine (T4) treatment] rats. A low level of circulating thyroid hormones induces a decrease of total thyroid calcium-binding protein concentration when compared with the concentration in unstimulated animals. Conversely, concentrations of annexins I, II and V increase. The accumulation of these proteins in two subcellular compartments (cytosolic and particulate fractions) can be reversed by addition of thyroid hormones. The finding of a specific increase in annexins concentration in thyroid-hormone-deficient rats, with a general decrease of the total calcium-binding protein content points to a very important role of these proteins in the cells. Furthermore, hyperthyroidisnt gives opposite results. To investigate the transduction pathway of annexins I-, II- and V-induced biosynthesis by thyroid hormones in thyroid glands, we used cultured pig thyroid cells as in vitro model system. In previous work [16], we have shown that annexin concentrations and localization are under TSH control via the adenylate cyclase pathway. In the presence of MeSur (in the culture medium), the protein-binding iodine remains low, indicative of weak thyroid hormone synthesis (data not shown) and that the annexins content is unchanged. These results suggest that, in thyroid tissue, an indirect mechanism links thyroid hormones to annexin expressions via the TSH feed-back loop, and excludes autocrine regulation.

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PubMed1994

Differential expression of thrombospondin, collagen, and thyroglobulin by thyroid-stimulating hormone and tumor-promoting phorbol ester in cultured porcine thyroid cells.

In the present study, we have investigated the potential regulation of thyroglobulin (Tg) and extracellular matrix components synthesis by thyroid-stimulating hormone (TSH) and tetradecanoyl phorbol-13-acetate (TPA) on thyroid cells. Porcine thyroid cells isolated by trypsin-EGTA digestion of thyroid glands were maintained in serum containing medium on poly (L-lysine)-coated dishes. Cells differentiated into follicular or vesicular-like structures were distinguished by their ability to organify Na[125I] and to respond to TSH stimulation. After an incubation of the cells with radiolabeled proline or methionine, two major proteins were identified, p450-480 and p290 (so named because of their molecular masses). Tg (p290) synthesis was demonstrated by the synthesis of [131I]-labeled polypeptides with electrophoretic properties identical to those of authentic Tg molecules. P450-480 resolved to M(r) 190,000 under reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) conditions. It was identified as thrombospondin by its reactivity with a monoclonal anti-human thrombospondin and by peptide sequencing of some of its tryptic fragments that displayed identity to thrombospondin I. Collagen synthesis was demonstrated by the formation of radioactive hydroxyproline and by the synthesis of pepsin-resistant polypeptides ranging from M(rs) 120,000 to 200,000. When the cells were cultured in the presence of 100 nM TPA, the culture medium contents of thrombospondin and collagen were increased by 2.7 and 1.6-fold, respectively, whereas Tg content was decreased by a factor 3.9. In contrast, the acute treatment of control cells with TPA induced a decrease in both Tg and collagen content by factors 3.0 and 1.5, respectively, and an increase in thrombospondin content by a factor 2.5. In the presence of 100 nM TPA, TSH (1 mU/ml) did not counteract the stimulating effect of TPA on extracellular matrix components synthesis. In contrast, when cells were cultured in the presence of TSH alone at concentrations higher than 0.1 mU/ml, collagen and thrombospondin in the medium were decreased by a factor 2.0 and 1.9, respectively, and TSH preferentially activated Tg synthesis. However, no acute response to TSH was observed in cells incubated for 2 days without effectors (control cells). On TSH differentiated cells, TPA decreased both collagen and Tg accumulation by factors 1.2 and 1.8, respectively, whereas it increased the one of thrombospondin by a factor 2. These results, together with the stimulating effect of TPA on TSH mediated cell proliferation, argue for a role of thrombospondin in cell adhesion and migration events within the thyroid epithelium.

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PubMed1994

Cyclic AMP regulation of annexins I, II, V synthesis and localization in cultured porcine thyroid cells.

Porcine thyroid cells cultured in the presence of TSH (0.1 mU/ml) or forskolin (10(-5) M) for 4 days display an increased annexin I, II, V biosynthesis when compared with unstimulated cells. Annexin I mostly accumulates in the cytosolic fraction and annexins II and V in the particulate fraction. TSH and forskolin affect in the same manner annexin biosynthesis and localization. In the TSH and forskolin treated cells PGE2 production is very low in comparison with the very high PLA2 activity observed in the dedifferentiated control cells. A strong inhibition of the PGE2 production is observed in control cells incubated with a purified annexin V preparation. These results suggest the existence, in porcine thyroid cells, of a cross-talk between the adenylyl cyclase system and the phospholipase A2 mediated pathways. Annexins' biosynthesis and localization are under the control of the adenylyl cyclase system and participate in this cross-talk.

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