scholarly journals Rapid regulation of thyroid sodium–iodide symporter activity by thyrotrophin and iodine

2005 ◽  
Vol 184 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Andrea C F Ferreira ◽  
Lívia P Lima ◽  
Renata L Araújo ◽  
Glaucia Müller ◽  
Renata P Rocha ◽  
...  

Transport of iodide into thyrocytes, a fundamental step in thyroid hormone biosynthesis, depends on the presence of the sodium–iodide symporter (NIS). The importance of the NIS for diagnosis and treatment of diseases has raised several questions about its physiological control. The goal of this study was to evaluate the influence of thyroid iodine content on NIS regulation by thyrotrophin (TSH) in vivo. We showed that 15-min thyroid radioiodine uptake can be a reliable measurement of NIS activity in vivo. The effect of TSH on the NIS was evaluated in rats treated with 1-methyl-2-mercaptoimidazole (MMI; hypothyroid with high serum TSH concentrations) for 21 days, and after 1 (R1d), 2 (R2d), or 5 (R5d) days of withdrawal of MMI. NIS activity was significantly greater in both MMI and R1d rats. In R2d and R5d groups, thyroid iodide uptake returned to normal values, despite continuing high serum TSH, possibly as a result of the re-establishment of iodine organification after withdrawal of MMI. Excess iodine (0.05% NaI for 6 days) promoted a significant reduction in thyroid radioiodide uptake, an effect that was blocked by concomitant administration of MMI, confirming previous findings that iodine organification is essential for the iodide transport blockade seen during iodine overload. Therefore, our data show that modulation of the thyroid NIS by TSH depends primarily on thyroid iodine content and, further, that the regulation of NIS activity is rapid.

2007 ◽  
Vol 51 (5) ◽  
pp. 672-682 ◽  
Author(s):  
Denise P. Carvalho ◽  
Andrea C.F. Ferreira

The thyroid gland has the ability to uptake and concentrate iodide, which is a fundamental step in thyroid hormone biosynthesis. Radioiodine has been used as a diagnostic and therapeutic tool for several years. However, the studies related to the mechanisms of iodide transport were only possible after the cloning of the gene that encodes the sodium/iodide symporter (NIS). The studies about the regulation of NIS expression and the possibility of gene therapy with the aim of transferring NIS gene to cells that normally do not express the symporter have also become possible. In the majority of hypofunctioning thyroid nodules, both benign and malignant, NIS gene expression is maintained, but NIS protein is retained in the intracellular compartment. The expression of NIS in non-thyroid tumoral cells in vivo has been possible through the transfer of NIS gene under the control of tissue-specific promoters. Apart from its therapeutic use, NIS has also been used for the localization of metastases by scintigraphy or PET-scan with 124I. In conclusion, NIS gene cloning led to an important development in the field of thyroid pathophysiology, and has also been fundamental to extend the use of radioiodine for the management of non-thyroid tumors.


Endocrinology ◽  
2009 ◽  
Vol 150 (3) ◽  
pp. 1084-1090 ◽  
Author(s):  
Aigerim Bizhanova ◽  
Peter Kopp

Thyroid hormones are essential for normal development and metabolism. Thyroid hormone biosynthesis requires iodide uptake into the thyrocytes and efflux into the follicular lumen, where it is organified on selected tyrosyls of thyroglobulin. Uptake of iodide into the thyrocytes is mediated by an intrinsic membrane glycoprotein, the sodium-iodide symporter (NIS), which actively cotransports two sodium cations per each iodide anion. NIS-mediated transport of iodide is driven by the electrochemical sodium gradient generated by the Na+/K+-ATPase. NIS is expressed in the thyroid, the salivary glands, gastric mucosa, and the lactating mammary gland. TSH and iodide regulate iodide accumulation by modulating NIS activity via transcriptional and posttranscriptional mechanisms. Biallelic mutations in the NIS gene lead to a congenital iodide transport defect, an autosomal recessive condition characterized by hypothyroidism, goiter, low thyroid iodide uptake, and a low saliva/plasma iodide ratio. Pendrin is an anion transporter that is predominantly expressed in the inner ear, the thyroid, and the kidney. Biallelic mutations in the SLC26A4 gene lead to Pendred syndrome, an autosomal recessive disorder characterized by sensorineural deafness, goiter, and impaired iodide organification. In thyroid follicular cells, pendrin is expressed at the apical membrane. Functional in vitro data and the impaired iodide organification observed in patients with Pendred syndrome support a role of pendrin as an apical iodide transporter. This review shows how the sodium-iodide symporter mediates the active transport of iodide at the basolateral membrane of thyrocytes and discusses biallelic mutations in NIS and the effects of pendrin.


Thyroid ◽  
2000 ◽  
Vol 10 (11) ◽  
pp. 939-943 ◽  
Author(s):  
Jan W.A. Smit ◽  
Janny P. Schröder-van der Elst ◽  
Marcel Karperien ◽  
Ivo Que ◽  
Gabri van der Pluijm ◽  
...  

2011 ◽  
Vol 96 (9) ◽  
pp. E1435-E1443 ◽  
Author(s):  
Garcilaso Riesco-Eizaguirre ◽  
Antonio De la Vieja ◽  
Irene Rodríguez ◽  
Soledad Miranda ◽  
Pilar Martín-Duque ◽  
...  

Abstract Context: Telomerase promoters (hTERT and hTR) are useful for transcriptional targeting in gene therapy models of cancer. Telomerase-driven expression of the sodium iodide symporter (NIS) in tumor cells has been successfully used as a reporter gene in vivo using positron emission tomography (PET) imaging. Objective: The aim of this study was to investigate the NIS-mediated therapeutic effect of telomerase promoters in a wide variety of human cancer cell lines. Design and Methods: Promoter fragments from either hTERT or hTR were used to drive the expression of NIS in cell lines derived from melanoma (M14), breast (MDA-MB-231), colon (HT-29), lung (H460), ovarian (OVCAR-3), and thyroid (TPC-1) carcinomas. Iodide uptake assays, protein immunodetection, and clonigenic assays were used to confirm NIS functional expression and the 131I-mediated cytopathic effect. Tumor xenografts in mice were infected with hTERT and hTR and then treated using radioiodide. Results: Both promoters were selectively active in cancer cells that were effectively killed by exposure to 131I. One single dose of 1 mCi 131I markedly suppressed tumor growth of melanoma-derived tumor xenografts compared with controls. This effect was more modest in colon cancer-derived xenografts in part due to the reduced infectivity and the tumor cystic nature. The therapeutic effect of hTR promoter was found to be stronger than that of hTERT promoter. Conclusions: These results demonstrate that telomerase-driven expression of NIS could potentially have applications for 131I therapy of a wide variety of cancers. Additionally, this is the first study to report NIS-mediated 131I therapy of melanoma tumors in vivo.


2016 ◽  
Author(s):  
Alice Fletcher ◽  
Vikki Poole ◽  
Bhavika Modasia ◽  
Waraporn Imruetaicharoenchoke ◽  
Rebecca Thompson ◽  
...  

2017 ◽  
Author(s):  
Alice Fletcher ◽  
Vikki Poole ◽  
Bhavika Modasia ◽  
Waraporn Imruetaicharoenchoke ◽  
Rebecca Thompson ◽  
...  

2005 ◽  
Vol 11 (4) ◽  
pp. 1483-1489 ◽  
Author(s):  
Roisin M. Dwyer ◽  
Elizabeth R. Bergert ◽  
Michael K. O'Connor ◽  
Sandra J. Gendler ◽  
John C. Morris

2007 ◽  
Vol 6 (7) ◽  
pp. 1130-1135 ◽  
Author(s):  
Hyun Joo Kim ◽  
Yong Hyun Jeon ◽  
Joo Hyun Kang ◽  
Yong Jin Lee ◽  
Kwang Kim ◽  
...  

2011 ◽  
Vol 210 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Vicki E Smith ◽  
Jayne A Franklyn ◽  
Christopher J McCabe

Pituitary tumor-transforming gene (PTTG)-binding factor (PBF; PTTG1IP) was initially identified through its interaction with the human securin, PTTG. Like PTTG, PBF is upregulated in multiple endocrine tumours including thyroid cancer. PBF is believed to induce the translocation of PTTG into the cell nucleus where it can drive tumourigenesis via a number of different mechanisms. However, an independent transforming ability has been demonstrated both in vitro and in vivo, suggesting that PBF is itself a proto-oncogene. Studied in only a limited number of publications to date, PBF is emerging as a protein with a growing repertoire of roles. Recent data suggest that PBF possesses a complex multifunctionality in an increasing number of tumour settings. For example, PBF is upregulated by oestrogen and mediates oestrogen-stimulated cell invasion in breast cancer cells. In addition to a possible role in the induction of thyroid tumourigenesis, PBF overexpression in thyroid cancers inhibits iodide uptake. PBF has been shown to repress sodium iodide symporter (NIS) activity by transcriptional regulation of NIS expression through the human NIS upstream enhancer and further inhibits iodide uptake via a post-translational mechanism of NIS governing subcellular localisation. This review discusses the current data describing PBF expression and function in thyroid cancer and highlights PBF as a novel target for improving radioiodine uptake and thus prognosis in thyroid cancer.


2007 ◽  
Vol 92 (10) ◽  
pp. 4046-4051 ◽  
Author(s):  
Huika Li ◽  
Kerry Richard ◽  
Brett McKinnon ◽  
Robin H. Mortimer

Abstract Context: Active placental transport of maternal iodide by the thyroidal sodium iodide symporter (NIS) provides an essential substrate for fetal thyroid hormone synthesis. NIS is expressed in trophoblast and is regulated by human choriogonadotropin (hCG). In thyroid, iodide down-regulates expression of several genes including NIS. Placentas of iodine-deficient rats demonstrate up-regulation of NIS mRNA, suggesting a role for iodide in regulating placental NIS. Objectives and Methods: The objectives were to examine effects of iodide on expression of NIS and hCG in BeWo choriocarcinoma cells. Gene expression was studied by quantitative real-time PCR. Effects on NIS protein expression were assessed by Western blotting. Functional activity of NIS was measured by 125I uptake. Expression of hCG protein was assessed by immunoassay of secreted hormone. Results: Iodide inhibited NIS mRNA and membrane protein expression as well as 125I uptake, which were paralleled by decreased βhCG mRNA expression and protein secretion. Iodide had no effects on pendrin expression. Addition of hCG increased NIS mRNA expression. This effect was partially inhibited by addition of iodide. The inhibitory effects of iodide on NIS mRNA expression were abolished by propylthiouracil and dithiothreitol. Conclusions: We conclude that expression of placental NIS is modulated by maternal iodide. This may occur through modulation of hCG effects on NIS and hCG gene expression.


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