scholarly journals Iodinated phospholipids and the in vitro iodination of proteins of dog thyroid gland

1977 ◽  
Vol 168 (2) ◽  
pp. 155-160 ◽  
Author(s):  
Joseph L. Rabinowitz ◽  
Carl J. Tavares
Keyword(s):  
Thyroid Gland ◽  
Plasma Membranes ◽  
Fatty Acyl ◽  
Thyroid Cell ◽  
Membrane Phospholipids ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
Covalently Linked ◽  
A Minor

Slices of dog thyroid gland were incubated with liposomes consisting of 125I-labelled phosphatidylcholine (the iodine was covalently linked to unsaturated fatty acyl chains). The 125I label of 125I-labelled liposomes was incorporated into thyroid protein and/or thyroglobulin at a higher rate than was the 131I label of either Na131I or 131I2. The iodine was shown to be protein-bound by the co-migration of the labelled iodine with protein under conditions where free iodine, iodide and lipid-bound iodine were removed from protein. The uptake of iodine from the iodinated phospholipid was probably due to phospholipid exchange between the iodinated liposomes and the thyroid cell membrane, since (a) 14C-labelled phospholipid was metabolized to 14CO2 and (b) many lipids in the tissue slice became 14C-labelled. A very strong inhibition of iodide ‘uptake’ from Na131I, caused by thiosulphate, produced only a minor inhibition of the incorporation of 125I from 125I-labelled liposomes into thyroid protein and/or thyroglobulin. This implies that free iodide may not necessarily be formed from the iodinated phospholipids before their entrance or utilization in the cell. Synthetic polytyrosine polypeptide suspensions showed some iodination by 131I-labelled liposomes. In tissues with low tyrosine contents, such as liver and kidney, only a trace uptake was observed. Salivary gland showed some uptake. Endoplasmic reticulum of thyroid gland showed a higher iodine uptake than that of the corresponding plasma membranes. These experiments, together with the demonstration of the diet-dependent presence of iodinated phospholipids in dog thyroid, leads us to suggest that iodination of the membrane phospholipids of thyroid cells may be directly or indirectly involved at some stage in the synthesis of thyroglobulin, or exists as a scavenger mechanism, to re-utilize and/or recover released iodine from unstable compounds inside the thyroid cell.

Evaluation of the rat thyroid cell strain FRTL-5 as an in-vitro bioassay system for thyrotrophin

1984 ◽  
Vol 101 (3) ◽  
pp. 269-NP ◽  
Author(s):  
S. P. Bidey ◽  
L. Chiovato ◽  
A. Day ◽  
M. Turmaine ◽  
R. P. Gould ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Human Thyroid ◽  
Thyroid Cell ◽  
Tissue Slices ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
Rat Thyroid ◽  
Bovine Tsh ◽  
Stimulation Of

ABSTRACT The cyclic AMP response to bovine TSH was characterized in a strain of rat thyroid follicular cells (FRTL-5) maintained in continuous culture. Significant stimulation of intracellular cyclic AMP was attained at a TSH dose of 5 μu./ml. Cyclic AMP accumulation continued to increase, at higher TSH doses, with no evidence for attainment of a maximum level at the highest dose tested (5 mu./ml). The precision of TSH measurement was better than 10% over the range 50–5000 μu./ml, comparing favourably with that observed with analogous assays based on human cells, tissue slices or membrane preparations. Using sequential subcultures of FRTL-5 cells, the between-assay variation in response to a single dose of a standard preparation of bovine TSH (53/11; 370 μu./ml) was of the order of 20% which compared favourably with the between-assay variation observed with different cultures of human thyroid cells. Prolongation of the incubation of FRTL-5 cells with TSH to 3 h revealed a progressive increase in the extracellular accumulation of cyclic AMP. Addition of TSH to resting FRTL-5 cells resulted in a stimulation of inorganic iodide uptake with pronounced bell-shaped dose–response characteristics. Thus a maximum uptake was observed at a TSH dose of 100 μu./ml with a significant reduction at higher doses. Acute stimulation of cells with TSH (100 μu./ml) resulted in a rapid and marked alteration in cell morphology, with evidence of cellular retraction and surface ruffling. J. Endocr. (1984) 101, 269–276

scholarly journals Regulation of thymosin beta10 expression by TSH and other mitogenic signals in the thyroid gland and in cultured thyrocytes

1999 ◽  
pp. 597-607 ◽  
Author(s):  
G Viglietto ◽  
D Califano ◽  
P Bruni ◽  
G Baldassarre ◽  
MT Vento ◽  
...  
Keyword(s):  
Thyroid Gland ◽  
Actin Polymerization ◽  
Mrna Level ◽  
Thyroid Cell ◽  
Dependent Manner ◽  
Follicular Cells ◽  
Thyroid Cells ◽  
Rat Thyroid

OBJECTIVE: To investigate the expression of thymosin beta10 - a small conserved acidic protein involved in the inhibition of actin polymerization - in human and experimental thyroid goiters as well as the regulation exerted by TSH on thymosin beta10 expression in thyroid follicular cells both in vivo and in vitro. DESIGN: To this aim, we have used 5 bioptic specimens from patients affected by thyroid goiter, a well known experimental model of thyroid goitrogenesis (rat fed with the drug propylthiouracil) and a cultured rat thyroid cell line (PC Cl 3 cells) as a model system. RESULTS: We report that the mRNA expression of thymosin beta10 is markedly enhanced in human goiters compared with normal thyroid. In vivo results showed that the steady-state level of thymosin beta10 mRNA is up-regulated in the thyroid gland of propylthiouracil-fed rats in parallel with follicular cell proliferation: iodide administration to goitrous rats, which induced a marked involution of thyroid hyperplasia, reduced the mRNA level of thymosin beta10. Finally, in vitro studies showed that in cultured rat thyrocytes, the expression of thymosin beta10 mRNA is induced in a time- and dose-dependent manner by the activation of pathways which are mitogenic for thyroid cells (i.e. the protein kinase (PK) A and PKC pathways). CONCLUSION: Taken together, the findings reported here demonstrate that thymosin beta10 expression is regulated by extracellular signals that stimulate growth of thyroid cells both in vitro and in vivo, and suggest a role for this protein in thyroid diseases characterized by proliferation of follicular cells.

scholarly journals Trace Amine-Associated Receptor 1 Trafficking to Cilia of Thyroid Epithelial Cells

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1518
Author(s):  
Maria Qatato ◽  
Vaishnavi Venugopalan ◽  
Alaa Al-Hashimi ◽  
Maren Rehders ◽  
Aaron D. Valentine ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Lines ◽  
Human Thyroid ◽  
Apical Plasma Membrane ◽  
Thyroid Cell ◽  
Thyroid Cells ◽  
Trace Amine ◽  
Rat Thyroid

Trace amine-associated receptor 1 (rodent Taar1/human TAAR1) is a G protein-coupled receptor that is mainly recognized for its functions in neuromodulation. Previous in vitro studies suggested that Taar1 may signal from intracellular compartments. However, we have shown Taar1 to localize apically and on ciliary extensions in rodent thyrocytes, suggesting that at least in the thyroid, Taar1 may signal from the cilia at the apical plasma membrane domain of thyrocytes in situ, where it is exposed to the content of the follicle lumen containing putative Taar1 ligands. This study was designed to explore mouse Taar1 (mTaar1) trafficking, heterologously expressed in human and rat thyroid cell lines in order to establish an in vitro system in which Taar1 signaling from the cell surface can be studied in future. The results showed that chimeric mTaar1-EGFP traffics to the apical cell surface and localizes particularly to spherical structures of polarized thyroid cells, procilia, and primary cilia upon serum-starvation. Moreover, mTaar1-EGFP appears to form high molecular mass forms, possibly homodimers and tetramers, in stably expressing human thyroid cell lines. However, only monomeric mTaar1-EGFP was cell surface biotinylated in polarized human thyrocytes. In polarized rat thyrocytes, mTaar1-EGFP is retained in the endoplasmic reticulum, while cilia were reached by mTaar1-EGFP transiently co-expressed in combination with an HA-tagged construct of the related mTaar5. We conclude that Taar1 trafficking to cilia depends on their integrity. The results further suggest that an in vitro cell model was established that recapitulates Taar1 trafficking in thyrocytes in situ, in principle, and will enable studying Taar1 signaling in future, thus extending our general understanding of its potential significance for thyroid autoregulation.

scholarly journals Acrylamide does not induce tumorigenesis or major defects in mice in vivo

2008 ◽  
Vol 198 (2) ◽  
pp. 301-307 ◽  
Author(s):  
Ling Jin ◽  
Vanessa Chico-Galdo ◽  
Claude Massart ◽  
Christine Gervy ◽  
Viviane De Maertelaere ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Chronic Administration ◽  
Serum Levels ◽  
Human Thyroid ◽  
Thyroid Cell ◽  
Thyroid Cells ◽  
Hormone Synthesis ◽  
Rat Thyroid

Chronic administration of acrylamide has been shown to induce thyroid tumors in rat. In vitro acrylamide also causes DNA damage, as demonstrated by the comet assay, in various types of cells including human thyroid cells and lymphocytes, as well as rat thyroid cell lines. In this work, mice were administered acrylamide in their drinking water in doses comparable with those used in rats, i.e., around 3–4 mg/kg per day for mice treated 2, 6, and 8 months. Some of the mice were also treated with thyroxine (T4) to depress the activity of the thyroid. Others were treated with methimazole that inhibits thyroid hormone synthesis and consequently secretion and thus induces TSH secretion and thyroid activation. These moderate treatments were shown to have their known effect on the thyroid (e.g. thyroid hormone and thyrotropin serum levels, thyroid gland morphology…). Besides, T4 induced an important polydipsia and degenerative hypertrophy of adrenal medulla. Acrylamide exerted various discrete effects and at high doses caused peripheral neuropathy, as demonstrated by hind-leg paralysis. However, it did not induce thyroid tumorigenesis. These results show that the thyroid tumorigenic effects of acrylamide are not observed in another rodent species, the mouse, and suggest the necessity of an epidemiological study in human to conclude on a public health policy.

scholarly journals Low Doses of Methylmercury Induce the Proliferation of Thyroid Cells In Vitro Through Modulation of ERK Pathway

2020 ◽  
Vol 21 (5) ◽  
pp. 1556 ◽  
Author(s):  
Valentina Maggisano ◽  
Stefania Bulotta ◽  
Marilena Celano ◽  
Jessica Maiuolo ◽  
Saverio Massimo Lepore ◽  
...  
Keyword(s):  
Cell Viability ◽  
Prolonged Exposure ◽  
Signal Transduction Pathway ◽  
Immunoblot Analysis ◽  
Thyroid Cell ◽  
Promoting Effect ◽  
Thyroid Cells ◽  
M Phase ◽  
High Concentrations

Exposure to environmental endocrine disruptors has been associated with an increased frequency of thyroid pathology. In this study, we evaluated the effects of various concentrations of methylmercury (MeHg) on immortalized, non-tumorigenic thyroid cells (Nthy-ori-3-1). Exposure to MeHg at 2.5 and 5 µM for 24 h caused a reduction in cell viability with a decrease of the cell population in sub-G0 phase, as detected by MTT and flow cytometry. Conversely, MeHg at the lower concentration of 0.1 µM increased the cell viability with a rise of G2/M phase. An immunoblot analysis showed higher expression levels of phospho-ERK and not of phospho-Akt. Further enhancement of the cell growth rate was observed after a prolonged exposure of the cells up to 18 days to MeHg 0.1 µM. The present findings demonstrate the toxicity of high concentrations of MeHg on thyroid cells, while showing that treatment with lower doses of Hg, as may occur after prolonged exposure to this environmental contaminant, exerts a promoting effect on thyroid cell proliferation, by acting on the ERK-mediated pro-oncogenic signal transduction pathway.

Effects of protein kinase C activators on the in-vitro action of thyrotrophin in pigs

1988 ◽  
Vol 118 (2) ◽  
pp. 199-203 ◽  
Author(s):  
J. Ginsberg ◽  
P. G. Murray
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Thyroid Function ◽  
Receptor Site ◽  
Thyroid Cell ◽  
Thyroid Cells ◽  
Cell Extracts ◽  
Kinase C

ABSTRACT The ability of the non-phorbol protein kinase C (PKC) activator 12-hydroxy-daphnetoxin (mezerein) to modulate differentiated thyroid function was examined in vitro. A dose-dependent inhibition of TSH-stimulated iodide organification was observed in porcine thyroid cells exposed to mezerein. Under identical conditions mezerein caused the translocation of PKC from its inactive cytosolic form to an active membrane-bound form in thyroid cell extracts. The relative biological potencies of mezerein and the phorbol ester, 12-0-tetradecanoylphorbol-13-acetate (TPA), to inhibit thyroid function in vitro corresponded to their abilities to activate PKC. This effect was also observed when dibutyryl cyclic AMP was used, implying a post-receptor site of action. To provide further evidence for this concept, the effects of mezerein and TPA on receptor-related events were studied. Neither mezerein nor TPA had any effect on the binding of radiolabelled TSH to solubilized porcine thyroid membranes. However, both mezerein and TPA were capable of stimulating cyclic AMP (cAMP) production in porcine thyroid cells in the basal state but could not augment TSH or forskolin-activated cAMP release. These data provide evidence that activation of PKC plays a role in the regulation of differentiated thyroid function in vitro and suggest that the effects of PKC are complex, with independent actions on cAMP accumulation and post-receptor events. J. Endocr. (1988) 118, 199–203

Connexin-32 acts as a downregulator of growth of thyroid gland

2008 ◽  
Vol 294 (2) ◽  
pp. E291-E299 ◽  
Author(s):  
Gaëlle Prost ◽  
Françoise Bernier-Valentin ◽  
Yvonne Munari-Silem ◽  
Samia Selmi-Ruby ◽  
Bernard Rousset
Keyword(s):  
Thyroid Gland ◽  
Sodium Perchlorate ◽  
Growth Potential ◽  
Thyroid Cell ◽  
Wild Type ◽  
Thyroid Cells ◽  
Growth Increase ◽  
Thyroid Hyperplasia ◽  
Regulatory Functions

Thyroid epithelial cells communicate through gap junctions formed from connexin (Cx)32, Cx43, and Cx26. We previously reported that reexpression of Cx32 in “gap junction-deficient” FRTL-5 and FRT thyroid cell lines induces a reduction of cell proliferation rate and an activation of expression of cell differentiation. The present study aimed at determining whether Cx32 could exert similar regulatory functions in vivo. We investigated morphological and functional characteristics of thyroid gland of Cx32-deficient mice (Cx32-KO), mice overexpressing Cx32 selectively in the thyroid (Cx32-T+), and Cx32-KO mice with a thyroid-selective Cx32 complementation obtained by crossing Cx32-KO and Cx32-T+ mice. In basal conditions, Cx32-KO mice did not present any detectable thyroid alteration, whereas Cx32-T+ mice showed a thyroid hypoplasia (20% reduction) associated with a slight increase in thyroid functional activity. Under thyrotropin stimulation (following sodium perchlorate treatment), Cx32-KO mice developed a larger goiter (≤65% increase) than wild-type littermates, whereas Cx32-T+ mice exhibited the same thyroid hyperplasia as wild-type mice. Restoration of Cx32 expression in the thyroid of Cx32-KO mice abrogated the thyroid growth increase related to Cx32 deficiency. All together, these data show that Cx32 acts as a downregulator of growth of thyroid gland; an excess of Cx32 limits growth of thyroid cells in the basal state, whereas a lack of Cx32 confers an additional growth potential to TSH-stimulated thyroid cells.

scholarly journals The Flavonoid Quercetin Induces AP-1 Activation in FRTL-5 Thyroid Cells

Antioxidants ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 112 ◽  
Author(s):  
Cesidio Giuliani
Keyword(s):  
Binding Site ◽  
Thyroid Function ◽  
Thyroid Cell ◽  
Consensus Binding Site ◽  
Thyroid Cells ◽  
Basal Activity ◽  
Reporter Vector ◽  
Rat Thyroid

Previous studies have shown that quercetin inhibits thyroid function both in vitro and in vivo. An attempt to evaluate the effect of quercetin at the promoter level of the thyroid-specific genes led to the observation that this compound induces the basal activity of the reporter vector. Therefore, the action of quercetin has been evaluated on the basal activity of several reporter vectors: The PGL3 basic, promoter and control vectors from Promega, and a pSV-based chloramphenicol acetyltransferase (CAT) reporter vector. In the Fisher Rat Thyroid cell Line FRTL-5 thyroid cells transiently transfected, quercetin 10 μM increased the basal activity of all the reporter vectors evaluated, although the degree of the effect was significantly different among them. The analysis of the difference among the regulatory regions of these vectors identified the activator protein 1 (AP-1) binding site as one of the potential sites involved in the quercetin effect. Electromobility shift assay experiments showed that the treatment with quercetin induced the binding of a protein complex to an oligonucleotide containing the AP-1 consensus binding site. This is the first study showing an effect of quercetin on AP-1 activity in thyroid cells. Further studies are in progress to understand the role of AP-1 activation in the effects of quercetin on thyroid function.

scholarly journals Reevaluation of the Effect of Iodine on Thyroid Cell Survival and Function Using PCCL3 and Nthy-ori 3-1 Cells

2020 ◽  
Vol 4 (11) ◽  
Author(s):  
Tomomi Kurashige ◽  
Mika Shimamura ◽  
Yuji Nagayama
Keyword(s):  
Normal Function ◽  
Iodine Uptake ◽  
Thyroid Cell ◽  
Dependent Manner ◽  
Messenger Rnas ◽  
Thyroid Cells ◽  
Excess Iodine ◽  
Wide Range ◽  
And Function

Abstract The appropriate amount of iodine is critical for normal function of thyroid cells synthesizing thyroid hormones. Although normal thyroid cell lines such as rat PCCL3 and FRTL5 and human Nthy-ori 3-1 have been widely used for in vitro studies on physiological and pathophysiological effects of iodine on thyroid cells, we have recently pointed out the critical differences between FRTL5/PCCL3 cells and Nthy-ori 3-1 cells. Therefore, we here directly compared some of the cellular characteristics—iodine uptake, differentiated status, iodine-induced cytotoxicity, and iodine-regulation of autophagy—between PCCL3 and Nthy-ori 3-1 cells. PCCL3 cells express messenger RNAs for thyrotropin receptor and sodium/iodine symporter and incorporate iodine in a thyrotropin-dependent manner, whereas Nthy-ori 3-1 cells do not either. Nevertheless, both cells were comparably resistant to iodine cytotoxicity: Only far excess iodine (5 × 10–2 M) killed 20% to 40% cells in 24 hours with perchlorate exhibiting no effect, suggesting this cytotoxic effect is due to extracellular iodine. In contrast, a wide range of iodine (5 × 10–9 to 5 × 10–2 M) induced autophagy in PCCL3 cells, which was abolished by perchlorate, indicating intracellular iodine-induction of autophagy, but this effect was not observed in Nthy-ori 3-1 cells. In conclusion, it is critical to discriminate the effect of iodine incorporated into cells from that of extracellular iodine on thyroid cells. Iodine-uptake competent thyroid cells such as PCCL3 and FRTL5 cells, not Nthy-ori 3-1 cells, should be used for studies on iodine effect on thyroid cells.

IN-VITRO STUDIES OF NORMAL HUMAN THYROID CELLS: RESPONSES TO THYROTROPHIN AND DIBUTYRYL CYCLIC AMP

1977 ◽  
Vol 72 (1) ◽  
pp. 87-96 ◽  
Author(s):  
S. P. BIDEY ◽  
P. MARSDEN ◽  
J. ANDERSON ◽  
C. G. McKERRON ◽  
H. BERRY
Keyword(s):  
Cyclic Amp ◽  
Thyroid Tissue ◽  
Three Dimensional ◽  
Human Thyroid ◽  
Dibutyryl Cyclic Amp ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
Normal Human

SUMMARY Follicular cells isolated from normal human thyroid tissue have been cultured for up to 140 h with bovine thyrotrophin (TSH) or dibutyryl cyclic AMP (DBcAMP). Both compounds induced marked reorganization of the cells into three-dimensional follicular structures, whilst non-supplemented cells assumed a monolayer form. Cultures treated initially with TSH or DBcAMP showed a greater iodide uptake capacity, in comparison with unsupplemented cultures, in which iodide uptake was markedly diminished after 24 h. The release of tri-iodothyronine (T3) and thyroxine (T4) into the medium was determined by radioimmunoassay. Both TSH- and DBcAMP-treated cells showed a significant increase in iodothyronine output compared with unsupplemented control cells. In contrast to the 'classical' TSH-induced depression of the T4:T3 ratio in vivo, an increase in the ratio was observed for both TSH- and DBcAMP-supplemented cells in vitro. The ratio was also significantly greater after TSH than after DBcAMP, and possible implications of this finding are discussed.

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