Endogenous thyrocyte-produced nitric oxide inhibits iodide uptake and thyroid-specific gene expression in FRTL-5 thyroid cells

Fozzatti, Laura; Vélez, María Laura; Lucero, Ariel Maximiliano; Nicola, Juan Pablo; Mascanfroni, Iván; Macció, Daniela R.; Pellizas, Claudia G.; Roth, German A.; Masini-Repiso, Ana M.

doi:10.1677/joe.1.06967

Cited by 22 publications

(23 citation statements)

References 42 publications

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“…Total RNA purification, cDNA synthesis, and PCR were performed as described (16). The primer sequences for TLR4 (555 bp) were 5Ј-CGCTTTCAGCTTTGCCTTCATTA C-3Ј (sense) and 5Ј-TGCTACT-TCCTTGTGCCC TGTGAG-3Ј (antisense), for CD14 (364 bp) were 5Ј-GCTCCCACTCTCAGAATC-3Ј (sense) and 5Ј-CGCAGGGTTCCGAA-TAGA-3Ј (antisense), and for MD2 (379 bp) were 5Ј-CTTTTCGACGCT-GCTTTCTC-3Ј (sense) and 5Ј-ATCTGTGATGGCCCTTAGGA-3Ј (antisense).…”

Section: Rna Extraction and Rt-pcrmentioning

confidence: 99%

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Functional Toll-Like Receptor 4 Conferring Lipopolysaccharide Responsiveness Is Expressed in Thyroid Cells

et al. 2009

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Lipopolysaccharide (LPS), a glycolipid found in the cell wall of Gram-negative bacteria, exerts pleiotropic biological effects in different cell types. LPS is mainly recognized by the Toll-like receptor (TLR) 4/MD2/Cluster of differentiation 14 complex (CD14). We previously demonstrated that LPS produced a direct action on thyroid cells, including up-regulation of thyroglobulin gene expression. This work aimed to study further the effect of LPS on thyroid function and to elucidate the mechanism by which LPS is recognized by the thyroid cell. We could detect the transcript and protein expression of TLR4, MD2, and CD14 in thyroid cells, and that these proteins are localized at the plasma membrane. The sodium iodide symporter (NIS) is the transporter involved in the iodide uptake, the first step in thyroid hormonogenesis. We demonstrated that LPS increases the TSH-induced iodide uptake and NIS protein expression. The LPS agonist lipid A reproduced LPS effect, whereas the LPS antagonist, polymyxin B, abrogated it. By the use of anti-TLR4 blocking antibodies and the transient expression of TLR4 dominant-negative forms, we evidenced the involvement of TLR4 in the LPS action. The enrichment of TLR4 expressing Fisher rat thyroid cell line-5 (FRTL-5) cells confirmed that TLR4 confers LPS responsiveness to thyroid cells. In conclusion, we revealed for the first time that all the components of the LPS receptor complex are expressed in thyroid cells. Evidence that the effects of LPS on rodent thyroid function involve TLR4-induced signaling was obtained. The fact that thyroid cells are able to recognize and respond to LPS supports a role of the endotoxin as a potential modifier of thyroid function.

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Section: Rna Extraction and Rt-pcrmentioning

confidence: 99%

“…The DNA amount was determined by the diphenylamine method on the material not extracted by ethanol after trichloroacetic acid precipitation (16). Iodide uptake was expressed as picomol of iodide per g DNA (pmol/g DNA).…”

Section: Iodide Uptakementioning

confidence: 99%

Functional Toll-Like Receptor 4 Conferring Lipopolysaccharide Responsiveness Is Expressed in Thyroid Cells

et al. 2009

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“…Although porcine thyrocytes re-organized into follicle-like structures similar to those seen in human, the TSH-induced increase in iodide uptake was slightly smaller than reported for human cells (7–10 times,[45,46]). More importantly, the reaction to thiamazole differed between porcine and human thyrocytes.…”

Section: Discussionmentioning

confidence: 70%

Interspecies differences in membrane-associated protease activities of thyrocytes and their relevance for thyroid cancer studies

Frőhlich

Maier

Wahl

2012

J Exp Clin Cancer Res

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BackgroundTo understand the role of proteases involved in human thyroid cancer progression and tissue invasion, thyrocytes from other species could potentially be used provided their characteristics are similar. It is not known whether dipeptidyl peptidase IV and aminopeptidase N activities, which are overexpressed in human thyroid cancer, are, as in human, also absent in normal thyrocytes of other species, making them suitable models for studies on the regulation of these proteases.MethodsTo assess the role of these proteases, activity was measured in thyroid tissue of human, mouse, rat, porcine, bovine and ovine origin. The lysosomal protease, dipeptidyl peptidase II, was used for comparison.ResultsMurine, rat, ovine, bovine and human thyrocytes all lacked dipeptidyl peptidase IV and aminopeptidase N activity, but porcine thyrocytes were found to possess both. In contrast, lysosomal dipeptidyl peptidase II was strongly expressed in all species. These activity patterns were maintained in cultured cells. Cultured porcine thyrocytes formed follicles with typical morphology upon stimulation with TSH but differed from human thyrocytes in their response to thiamazole.ConclusionsThese species differences in the expression of dipeptidyl peptidase IV and aminopeptidase N, indicate that porcine thyrocytes cannot be considered appropriate for the study of proteases in human cancer development.

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“…The 125 I − accumulated in the cells was extracted with ice‐cold ethanol and quantified in a γ‐counter. For standardization, the amount of DNA was determined by the diphenylamine method after trichloroacetic acid precipitation (Fozzatti et al 2007).…”

Section: Methodsmentioning

confidence: 99%

“…Total RNA purification and cDNA synthesis were performed as previously described (Fozzatti et al 2007). The qPCR analysis was performed using an ABI Prism 7500 detection system (Applied Biosystems, Foster City, CA, USA) and SYBR green chemistry as previously described (Nicola et al 2010).…”

Section: Methodsmentioning

confidence: 99%

Dietary iodide controls its own absorption through post‐transcriptional regulation of the intestinal Na⁺/I⁻ symporter

Nicola

Reyna-Neyra

Carrasco

et al. 2012

The Journal of Physiology

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Key points• Expression of the Na + /I − symporter (NIS) at the apical surface of the epithelium of the small intestine is key to I − absorption, the first step in I − metabolism.− at high concentrations in enterocytes decreases its own NIS-mediated uptake by a newly discovered mechanism, downregulating NIS expression at the plasma membrane, increasing NIS protein degradation and decreasing NIS mRNA levels by reducing NIS mRNA stability, involving the NIS 3 -untranslated region.• In conclusion, we have uncovered that I − regulates intestinal NIS expression, and thus its own intestinal absorption, by a complex array of post-transcriptional mechanisms. Abstract Dietary I− absorption in the gastrointestinal tract is the first step in I − metabolism. Given that I− is an essential constituent of the thyroid hormones, its concentrating mechanism is of significant physiological importance. We recently described the expression of the Na + /I − symporter (NIS) on the apical surface of the intestinal epithelium as a central component of the I − absorption system and reported reduced intestinal NIS expression in response to an I − -rich diet in vivo. Here, we evaluated the mechanism involved in the regulation of NIS expression by I − itself in enterocytes. Excess I − reduced NIS-mediated I − uptake in IEC-6 cells in a dose-and time-dependent fashion, which was correlated with a reduction of NIS expression at the plasma membrane. Perchlorate, a competitive inhibitor of NIS, prevented these effects, indicating that an increase in intracellular I − regulates NIS. Iodide induced rapid intracellular recruitment of plasma membrane NIS molecules and NIS protein degradation. Lower NIS mRNA levels were detected in response to I − treatment, although no transcriptional effect was observed. Interestingly, I − decreased NIS mRNA stability, affecting NIS translation. Heterologous green fluorescent protein-based reporter constructs revealed a significant repressive effect of the I − -targeting NIS mRNA 3 untranslated region. In conclusion, excess I − downregulates NIS expression in enterocytes by virtue of a complex mechanism. Our data suggest that I − regulates intestinal NIS mRNA expression at the post-transcriptional level as part of an autoregulatory effect of I − on its own metabolism.

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Endogenous thyrocyte-produced nitric oxide inhibits iodide uptake and thyroid-specific gene expression in FRTL-5 thyroid cells

Cited by 22 publications

References 42 publications

Functional Toll-Like Receptor 4 Conferring Lipopolysaccharide Responsiveness Is Expressed in Thyroid Cells

Functional Toll-Like Receptor 4 Conferring Lipopolysaccharide Responsiveness Is Expressed in Thyroid Cells

Interspecies differences in membrane-associated protease activities of thyrocytes and their relevance for thyroid cancer studies

Dietary iodide controls its own absorption through post‐transcriptional regulation of the intestinal Na⁺/I⁻ symporter

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Endogenous thyrocyte-produced nitric oxide inhibits iodide uptake and thyroid-specific gene expression in FRTL-5 thyroid cells

Cited by 22 publications

References 42 publications

Functional Toll-Like Receptor 4 Conferring Lipopolysaccharide Responsiveness Is Expressed in Thyroid Cells

Functional Toll-Like Receptor 4 Conferring Lipopolysaccharide Responsiveness Is Expressed in Thyroid Cells

Interspecies differences in membrane-associated protease activities of thyrocytes and their relevance for thyroid cancer studies

Dietary iodide controls its own absorption through post‐transcriptional regulation of the intestinal Na+/I− symporter

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Dietary iodide controls its own absorption through post‐transcriptional regulation of the intestinal Na⁺/I⁻ symporter