Polarized properties of thyroid cells: A study with cultured porcine cells

1987 ◽  
Vol 116 (1_Suppl) ◽  
pp. S220-S224 ◽  
Author(s):  
Jean Mauchamp ◽  
Odile Chabaud ◽  
Marianne Chambard ◽  
Corinne Gerard ◽  
Claude Penel ◽  
...  

Abstract. In primary culture porcine cells form polarized cell layers. We have designed culture conditions in which we can have access to only one side of the cell layer, either the apical or the basal surface. In addition, using culture chambers with permeable bottom we can have access to either side of the cell layer which separates two compartments. Using these organized systems we have shown that the iodide concentrating mechanism and the TSH-reseptor adenyl cyclase complex are localized on the basolateral domain of the thyroid cell plasma membrane. We also demonstrated the existence on the apical surface of an amiloride sensitive sodium uptake. Finally we observed that about 10% of newly synthesized thyroglobulin appears to be secreted directly into the basal compartment, 90% being secreted in the apical compartment.

2004 ◽  
pp. 841-849 ◽  
Author(s):  
A Demelash ◽  
JO Karlsson ◽  
M Nilsson ◽  
U Bjorkman

OBJECTIVE: Hydrogen peroxide (H2O2), necessary for thyroid hormonogenesis, is produced at the apical surface of the thyroid follicular epithelium. Excess H2O2 is potentially cytotoxic and may contribute to the development of hypothyroidism, e.g. in severe selenium deficiency. Yet it is unclear how H2O2 contributes to thyroid cell death. DESIGN AND METHODS: H2O2-induced apoptosis and necrosis were studied in primary cultured pig thyroid cells. Glutathione peroxidase (GPx) activity was altered by culture in low serum with or without selenite substitution. Apoptosis was evaluated by spectrofluorometric measurement of caspase-3-specific substrate cleavage, and by analysis of DNA fragmentation by agarose gel electrophoresis. Necrosis was detected by 51Cr release from prelabeled cells. RESULTS: Exogenous H2O2 dose-dependently (100-400 micromol/l) activated caspase-3 within 3-12 h, and DNA degradation was observed after 24 h. The potency of H2O2 to induce apoptosis was low compared with that of staurosporine, a strong proapoptotic agent. H2O2-treated cells with reduced GPx activity showed increased caspase-3 activation. Incubation of serum-starved cells with selenite (10-100 nmol/l) normalized the GPx activity and reduced the activation of caspase-3 by H2O2. High H2O2 concentrations (400-800 micromol/l) were required to obtain necrosis. The H2O2-induced necrosis was exaggerated by both low GPx activity and catalase inhibition. CONCLUSIONS: Cytotoxic effects of H2O2 on thyroid cells include caspase-3-dependent apoptosis that occurs at H2O2 concentrations insufficient to induce necrosis. Selenium deficiency aggravates the apoptotic response, probably due to impaired capacity of GPx to degrade H2O2.


2000 ◽  
Vol 85 (9) ◽  
pp. 3458-3467
Author(s):  
Michele Marinò ◽  
Luca Chiovato ◽  
Nicholas Mitsiades ◽  
Francesco Latrofa ◽  
David Andrews ◽  
...  

Abstract After its endocytosis from the colloid, some thyroglobulin (Tg) is transcytosed intact across thyrocytes, accounting in part for its presence in the circulation. We previously showed that megalin (gp330), an endocytic Tg receptor, mediates apical to basolateral Tg transcytosis. Here we investigated whether a portion of megalin remains combined with Tg after its transcytosis, using studies with cultured thyroid cells and in vivo observations. FRTL-5 cells, a rat thyroid cell line, cultured on filters in dual chambers form tight junctions and exhibit features of polarity, with expression of megalin exclusively on the upper (apical) surface. After the addition of unlabeled Tg to the upper chamber and incubation at 37 C, some Tg was transcytosed intact across FRTL-5 cells into the lower chamber. Two antimegalin ectodomain antibodies precipitated transcytosed Tg in fluids collected from the lower chamber. After the addition of Tg to surface-biotinylated FRTL-5 cells, an anti-Tg antibody and the two antimegalin ectodomain antibodies precipitated high molecular mass biotinylated material in fluids collected from the lower chamber, corresponding to much of the megalin ectodomain, as well as smaller amounts of lower molecular mass material. The results indicate that Tg transcytosed across FRTL-5 cells remains complexed with megalin ectodomain components, which we refer to as megalin secretory components. In aminotriazole-treated rats, which develop increased megalin-mediated Tg transcytosis, antimegalin antibodies precipitated some of the Tg in the serum. Tg was also precipitated by antimegalin antibodies in sera from patients with Graves’ disease, in which we found increased megalin expression on the apical surface of thyrocytes. In contrast, in thyroidectomized patients with metastatic papillary thyroid carcinoma, in whom Tg is directly secreted by neoplastic thyroid cells into the circulation rather than transcytosed, serum Tg was not precipitated by antimegalin antibodies. The detection of Tg-megalin complexes may help identify the source of serum Tg in patients with thyroid diseases.


2008 ◽  
Vol 295 (5) ◽  
pp. C1445-C1453 ◽  
Author(s):  
Sarah J. Heaton ◽  
John J. Eady ◽  
Mary L. Parker ◽  
Kathryn L. Gotts ◽  
Jack R. Dainty ◽  
...  

BeWo cells are a placental cell line that has been widely used as an in vitro model for the placenta. The b30 subclone of these cells can be grown on permeable membranes in bicameral chambers to form confluent cell layers, enabling rates of both nutrient uptake into the cells from the apical surface and efflux from the basolateral membrane to be determined. The aim of this study was to evaluate structural and functional properties of confluent b30 BeWo cell layers grown in bicameral chambers, focusing on the potential application for studying receptor-mediated uptake and transport of transferrin (Tf)-bound iron (Fe-Tf). While it proved extremely difficult to establish and maintain an intact BeWo cell monolayer, it was possible to grow the cells to a confluent multilayer. Iron, applied as Fe-Tf, was rapidly transported across this cell layer; 9.3 ± 0.5% of the total dose was transported after 8 h, equivalent to 38.8 ± 2.1 pmol·cm−2·h−1. Transfer of Tf across the cell layer was much more limited; 2.4 ± 0.2% of the total dose was transported after 8 h, equivalent to 5.0 ± 0.4 pmol·cm−2·h−1. Compartmental modeling of these data suggested that iron was transported across the cell layer predominantly, if not exclusively, via a transcellular route, whereas Tf taken up into the cells was predominantly recycled back to the apical compartment. The results suggest that these cells are very efficient at transporting iron and, under carefully controlled conditions, can be a valuable tool for the study of iron transport in the placenta.


Endocrine ◽  
2021 ◽  
Author(s):  
Francesca Coperchini ◽  
Gianluca Ricci ◽  
Laura Croce ◽  
Marco Denegri ◽  
Rubina Ruggiero ◽  
...  

Abstract Introduction Angiotensin-converting-enzyme-2 (ACE-2) was demonstrated to be the receptor for cellular entry of SARS-CoV-2. ACE-2 mRNA was identified in several human tissues and recently also in thyroid cells in vitro. Purpose Aim of the present study was to investigate the effect of pro-inflammatory cytokines on the ACE-2 mRNA levels in human thyroid cells in primary cultures. Methods Primary thyroid cell cultures were treated with IFN-γ and TNF-α alone or in combination for 24 h. ACE-2 mRNA levels were measured by RT-PCR. As a control, the levels of IFN-γ inducible chemokine (CXCL10) were measured in the respective cell culture supernatants. Results The mean levels of ACE-2 mRNA increased after treatment with IFN-γ and TNF-α in all the thyroid cell preparations, while the combination treatment did not consistently synergically increase ACE-2-mRNA. At difference, CXCL10 was consistently increased by IFN-γ and synergically further increased by the combination treatment with IFN-γ + TNF-α, with respect to IFN-γ alone. Conclusions The results of the present study show that IFN-γ and, to a lesser extent TNF-α consistently increase ACE-2 mRNA levels in NHT primary cultures. More interestingly, the combined stimulation (proven to be effective according to the synergic effect registered for CXCL10) produces different responses in terms of ACE-2 mRNA modulation. These results would suggest that elevated levels of pro-inflammatory cytokines could facilitate the entering of the virus in cells by further increasing ACE-2 expression and/or account for the different degree of severity of SARS-COV-2 infection. This hypothesis deserves to be confirmed by further specific studies.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1518
Author(s):  
Maria Qatato ◽  
Vaishnavi Venugopalan ◽  
Alaa Al-Hashimi ◽  
Maren Rehders ◽  
Aaron D. Valentine ◽  
...  

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.


Methods ◽  
1997 ◽  
Vol 12 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Matthew F Mescher ◽  
Elena Savelieva

1960 ◽  
Vol 20 (2) ◽  
pp. 83-NP ◽  
Author(s):  
W. J. IRVINE

SUMMARY Human thyroid cells were grown in tissue culture in media containing normal human serum, Hashimoto serum, and rabbit sera containing antibodies to purified human thyroglobulin and to crude thyroid extract, respectively. The thyroid cells grew equally well in all media, with the exception of the rabbit serum containing antibodies to crude thyroid extract. Intact thyroid cells obtained from tissue culture failed to fix Hashimoto antibodies in the presence of complement, whereas the constituents of disrupted thyroid cells gave a strongly positive complement-fixation test with Hashimoto serum. It is therefore suggested that the intact thyroid cell is impermeable to complement-fixing Hashimoto antibody. The evidence afforded by the present work adds further weight to the belief that Hashimoto's disease may not be due to a simple auto-immunizing process consequent upon the interaction of thyroid antigen and the known circulating auto-antibodies. Evidence in support of an alternative hypothesis involving 'cell-bound' antibodies with disruption of the follicular basement membrane is discussed.


1981 ◽  
Vol 9 (2) ◽  
pp. 232P-232P
Author(s):  
G. J. Belsham ◽  
R. W. Brownsey ◽  
R. M. Denton

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