2-iodohexadecanal induces autophagy during goiter involution.

BACKGROUND: Iodine plays an important role in thyroid physiology and biochemistry. The thyroid is capable of producing different iodolipids such as 2-iodohexadecanal (2-IHDA). Data from different laboratories have shown that 2-IHDA inhibits several thyroid parameters and it has been postulated as intermediary on the action of iodide function. OBJECTIVE: To explore different mechanisms involved during the involution of the hyperplastic thyroid gland of Wistar rats towards normality induced by 2-IHDA. METHODS: Goiter was induced by the administration of MMI for 10 days, then the treatment was discontinued and Wistar rats were injected with 2-IHDA or KI. RESULTS: During involution, 2-IHDA treatment reduced PCNA expression compared to spontaneous involution. KI treatment caused an increase of Caspase-3 activity and TUNEL-positive cells. In contrast, 2-IHDA failed to alter this value but induced an increase of LC3B expression. KI but not 2-IHDA led to an increase in peroxides levels, catalase and glutathione peroxidase activity. CONCLUSIONS: We demonstrated that 2-IHDA, in contrast to iodide, did not lead to an increase in oxidative stress or apoptosis induction, indicating that the involution triggered by 2-IHDA in Wistar rats, is primarily due to the inhibition of cell proliferation and the induction of autophagy.

Immunophenotyping with high-dimensional flow cytometry identifies Treg cell subsets associated with recurrence in papillary thyroid carcinoma.

The activation of Treg cell subsets is critical for the prognosis of tumor patients; however, their heterogeneity and disease association in papillary thyroid carcinoma (PTC) need further investigation. We performed high-dimensional flow cytometry for immunophenotyping on thyroid tissues and matched peripheral blood samples from patients with multinodular goiters or PTC. We analyzed CD4+ T cell and Treg cell phenotypes and compared the recurrence-free survival of PTC patients with different Treg cell subset characteristics using TCGA. Furthermore, PTC recurrent and non-recurrent group were compared by multiplex immunohistochemistry. High-dimensional flow cytometry and bioinformatics analysis revealed an enrichment of Tregs in tumors compared with multinodular goiters and peripheral blood specimens. Moreover, effector Tregs (e-Tregs) as well as FOXP3+ non-Tregs were enriched in tumor samples, and the expression of CD39, PD-1, and CD103 increased on tumor Tregs. TCGA data analysis showed that individuals with CD39hi PD-1loCD103loe-Treghi and CD39loPD-1loCD103hie-Treghi expression patterns had a high recurrence rate. According to the multiplex immunohistochemistry and analysis, compared with non-recurrent group, the proportion of high recurrence rate effector Treg clusters (CD39+PD-1-CD103- plus CD39-PD-1-CD103+) was increased in recurrent patients. Overall, our results highlight the potential of e-Treg subsets as future immunotherapy targets for PTC recurrence.

Maintaining the thyroid gland in mutant thyroglobulin-induced hypothyroidism requires thyroid cell proliferation that must continue in adulthood.

Congenital hypothyroidism with biallelic thyroglobulin (Tg protein, encoded by the TG gene) mutation is an endoplasmic reticulum (ER) storage disease. Many patients (and animal models) grow an enlarged thyroid (goiter), yet some do not. In adulthood, hypothyroid TGcog/cog mice (bearing a Tg-L2263P mutation) exhibit a large goiter, whereas adult WIC rats bearing the TGrdw/rdw mutation (Tg-G2298R) exhibit a hypoplastic thyroid. Homozygous TG mutation has been linked to thyroid cell death, and cytotoxicity of the Tg-G2298R protein was previously thought to explain the lack of goiter in WIC-TGrdw/rdw rats. However, recent studies revealed that TGcog/cog mice also exhibit widespread ER stress-mediated thyrocyte death, yet under continuous feedback stimulation, thyroid cells proliferate in excess of their demise. Here, to examine the relative proteotoxicity of the Tg-G2298R protein, we have used CRISPR-CRISPR-associated protein 9 technology to generate homozygous TGrdw/rdw knock-in mice in a strain background identical to that of TGcog/cog mice. TGrdw/rdw mice exhibit similar phenotypes of defective Tg protein folding, thyroid histological abnormalities, hypothyroidism, and growth retardation. TGrdw/rdw mice do not show evidence of greater ER stress response or stress-mediated cell death than TGcog/cog mice, and both mouse models exhibit sustained thyrocyte proliferation, with comparable goiter growth. In contrast, in WIC-TGrdw/rdw rats, as a function of aging, the thyrocyte proliferation rate declines precipitously. We conclude that the mutant Tg-G2298R protein is not intrinsically more proteotoxic than Tg-L2263P; rather, aging-dependent difference in maintenance of cell proliferation is the limiting factor, which accounts for the absence of goiter in adult WIC-TGrdw/rdw rats.

Pathogenesis of Multinodular Goiter in Elderly XB130-Deficient Mice: Alteration of Thyroperoxidase Affinity with Iodide and Hydrogen Peroxide.

Background: Multinodular goiter (MNG) is the most common disorder of the thyroid gland. Aging and genetic mutations that impair thyroid hormone (TH) production have been implicated in the development of MNG. XB130 is an adaptor/scaffold protein predominantly expressed in the thyroid gland. XB130 deficiency leads to transient postnatal growth retardation in mice due to congenital hypothyroidism. We studied the formation of MNG and possible mechanisms in elderly mice. Methods: Thyroid glands of male and female Xb130-knockout (Xb130-/-), heterozygous (Xb130+/-), and wild-type (Xb130+/+) mice at the ages of 12-20 months were harvested for visual examination, histopathological, and immunohistological analyses. Blood and thyroid samples were collected after feeding elderly mice with a low iodine diet for 125I uptake and perchlorate discharge assay. The activity of thyroperoxidase (Tpo) was examined by spectrophotometric evaluation of iodide oxidation. Results: While moderate MNG was seen in Xb130+/+ and Xb130+/- mice, severe MNG, characterized by multiple nodules intermixed with dilated colloid-rich macrofollicles, was found only in Xb130-/- mice at 18 months. Thyrocyte cytoskeletal structure and cell adhesion molecules were disorganized, and TH production was significantly reduced. Reduced iodide organification was seen in elderly Xb130+/+ mice and further enhanced in Xb130-/- mice. In Xb130+/+ mice, Tpo shows high affinity with hydrogen peroxide (H2O2) throughout aging, but reduced affinity with iodide in an age-dependent manner. By contrast, in elderly Xb130-/- mice, the affinity of Tpo for iodide remained high, but the affinity of Tpo for H2O2 was reduced. Conclusions: The pathophysiological features in the thyroid glands of aged Xb130-/- mice closely resemble the features of MNG in humans. Moderate MNG in elderly mice was dramatically aggravated by XB130 deficiency. Reduced affinity of Tpo for H2O2 may contribute to MNG development via oxidative stress. This could be specific to XB130 deficiency but also could be a common mechanism in MNG. Its clinical relevance should be further investigated.

Periostin expression and its supposed roles in benign and malignant thyroid nodules: an immunohistochemical study of 105 cases.

BACKGROUND: Thyroid tumors are often difficult to histopathologically diagnose, particularly follicular adenoma (FA) and follicular carcinoma (FC). Papillary carcinoma (PAC) has several histological subtypes. Periostin (PON), which is a non-collagenous extracellular matrix molecule, has been implicated in tumor invasiveness. We herein aimed to elucidate the expression status and localization of PON in thyroid tumors. METHOD: We collected 105 cases of thyroid nodules, which included cases of adenomatous goiter, FA, microcarcinoma (MIC), PAC, FC, poorly differentiated carcinoma (PDCa), and undifferentiated carcinoma (UCa), and immunohistochemically examined the PON expression patterns of these lesions. RESULTS: Stromal PON deposition was detected in PAC and MIC, particularly in the solid/sclerosing subtype, whereas FA and FC showed weak deposition on the fibrous capsule. However, the invasive and/or extracapsular regions of microinvasive FC showed quite strong PON expression. Except for it, we could not find any significant histopathological differences between FA and FC. There were no other significant histopathological differences between FA and FC. Although PDCa showed a similar PON expression pattern to PAC, UCa exhibited stromal PON deposition in its invasive portions and cytoplasmic expression in its carcinoma cells. Although there was only one case of UCa, it showed strong PON immunopositivity. PAC and MIC showed similar patterns of stromal PON deposition, particularly at the invasive front. CONCLUSIONS: PON may play a role in the invasion of thyroid carcinomas, particularly PAC and UCa, whereas it may act as a barrier to the growth of tumor cells in FA and minimally invasive FC.

Functions of the Thyroid-Stimulating Hormone on Key Developmental Features Revealed in a Series of Zebrafish Dyshormonogenesis Models.

The hypothalamic-pituitary-thyroid (HPT) axis regulates many critical features in vertebrates. Utilizing TALENs and CRISPR/Cas9 techniques, thyroid-stimulating hormone subunit beta a (tshba), thyroglobulin (tg), and solute carrier family 16 member 2 (slc16a2) mutant zebrafish lines were generated. Among the three mutants, the earliest time point for the significantly altered T3 contents was observed in tshba mutants, which resulted in the most severe defects, including typical defects such as the retardation of inflated anterior swimming bladder (aSB), proper formation of fin ray and posterior squamation (SP), the larval-to-juvenile transition (LTJT) process, juvenile growth retardation, and mating failure. In tg mutants, which are actually compensated with an alternative splicing form, growth retardation was observed in the juvenile stage without LTJT and reproductive defects. The evident goiter phenotype was only observed in tg- and slc16a2 mutants, but not in tshba mutants. Other than goiters being observed, no other significant developmental defects were found in the slc16a2 mutants. Regarding the reproductive defects observed in tshba mutants, the defective formation of the secondary sex characteristics (SSCs) was observed, while no obvious alterations during gonad development were found. Based on our analyses, zebrafish at the 6-12 mm standard length or 16-35 days post-fertilization (dpf) should be considered to be in their LTJT phase. Using a series of zebrafish dyshormonogenesis models, this study demonstrated that the TSH function is critical for the proper promotion of zebrafish LTJT and SSC formation. In addition, the elevation of TSH levels appears to be essential for goiter appearance in zebrafish.

A case-control study on the association of mineral elements exposure and thyroid tumor and goiter.

Thyroid tumor and thyroid goiter are prevalent disease around the world. In this case-control study, we investigated the association between exposure to a total of twelve mineral elements and thyroid disease as well as thyroid functions. Participants with thyroid tumor or goiter (N = 197) were matched with a healthy population (N = 197) by age (± 2 years old) and same sex. Questionnaires were used to collect data about the demographic characteristics and information of subjects. Serum and urine samples were collected simultaneously for each of the subjects. Mineral elements, iodine level of urine and levels of the total seven thyroid function indexes in serum were detected respectively. Conditional logistic regression was applied to estimate the associations between mineral elements and the risk of thyroid tumor and goiter through single-element models and multiple-element models. Multiple linear regression was used to evaluate relationships between mineral elements and percentage changes of thyroid functions. Higher concentrations of mineral elements in the recruited population were found in this study than other comparable studies, and the levels of chromium (Cr), manganese (Mn), nickel (Ni), arsenic (As), cadmium (Cd), selenium (Se), antimony (Sb), thallium (Tl) and lead (Pb) in the case group were lower than the control group. According to the single-element models, Cr, Mn, Ni, Sb and Tl showed significant negative associations with the risk of thyroid tumor and goiter, and, Cd showed nonmonotonic dose response. Cd and mercury (Hg) showed a nonmonotonic percentage change with T4, while Tl was associated with the increased FT4 in the control group. Therefore, Cd, Hg and Tl may disturb the balance of thyroid function to some extent, and Cr, Mn, Ni, Cd, Sb, and Tl may become potential influencing factors for the risk of thyroid tumor and goiter.

A matrix-assisted laser desorption/ionization imaging mass spectrometric approach to study weight-related changes within thyroid tissue.

Obesity is associated with numerous comorbidities along with abnormalities of the endocrine system, more commonly manifesting as dysfunctions of the thyroid gland such as goiter. Changes in weight, especially an increase, could lead to an increase in the incidence of thyroid dysfunction; however, its pathophysiology remains to be elucidated. In the present study, we aimed to interrogate the changes in the protein distribution and abundance between the lean patients and patients with obesity thyroid tissue sections through utilizing this technique. The FFPE-fixed thyroid tissue blocks from the selected cases and controls were identified and targeted for matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) analysis. Patients in the 30 to 75 years age group and undergoing total thyroidectomy for benign thyroid disease were recruited. Patients with thyroid cancers, autoimmune disorders, and other inflammatory conditions were excluded from the study. The selected patients were divided into two groups according to their BMIs: lean (BMI < 25) and obese (BMI > 35). An initial trial set was used as a pilot study for the optimization of the MALDI IMS protocol that was next applied to the selected thyroid tissues. MALDI IMS data from all the samples were aligned and statistical analysis carried out by k-means and linear discriminant analysis (LDA) classification model using principle component analysis (PCA) results were evaluated between the two groups: controls (lean) and cases (obese). Receiver operator characteristic (ROC) curves were alternatively used to calculate the variability of the identified peptides. The discriminating peptides were also independently identified and related to their corresponding proteins by using liquid chromatography and tandem mass spectrometry (LC-MS/MS) analyses. Eight peptides mainly from thyroglobulin were found to be upregulated whereas 10 others were found to be downregulated in the lean compared to the obese group. Through this technique, we will be able to better understand the relationship between the disease entity and obesity.

The correlation between ultrasonographic features, bFGF, and the local invasiveness of thyroid papillary carcinoma.

The present study aimed to investigate the correlation between ultrasonographic features, basic fibroblast growth factor (bFGF), and the local invasiveness of papillary thyroid carcinoma (PTC).A total of 350 samples of thyroid nodules were collected. Routine ultrasonography was performed before the operation and routine pathological diagnosis and bFGF detection were performed after the operation.'These 350 samples of thyroid nodules included 90 samples of nodular goiter, 36 samples of focal thyroiditis, and 224 samples of PTC. A total of 326 thyroid nodules were examined for bFGF. The results revealed that the difference in the expression of bFGF between the benign and malignant groups was statistically significant (P < .05) and the difference in the positive expression of bFGF between the invasive and non-invasive PTC groups was statistically significant (P < .05).Whether the shape of PTC is regular or not and whether there is micro-calcification in PTC and other ultrasonographic features, the size and location of the lesions and the age of the patient help make a preliminary prediction of local invasiveness before the operation. Postoperative detection of bFGF is helpful for further risk assessments of PTC.

Inhibition of the thyroid hormonogenic H2O2 production by Duox/DuoxA in zebrafish reveals VAS2870 as a new goitrogenic compound.

Thyroid hormone (TH) synthesis requires extracellular hydrogen peroxide generated by the NADPH oxidases, DUOX1 and DUOX2, with maturation factors, DUOXA1 and DUOXA2. In zebrafish, only one duox and one duoxa gene are present. Using a thyroid-specific reporter line, we investigated the role of Duox and Duoxa for TH biosynthesis in zebrafish larvae. Analysis of several zebrafish duox and duoxa mutant models consistently recovered hypothyroid phenotypes with hyperplastic goiter caused by impaired TH synthesis. Mutant larvae developed enlarged thyroids and showed increased expression of the EGFP reporter and thyroid functional markers including wild-type and mutated duox and duoxa transcripts. Treatment of zebrafish larvae with the NADPH oxidase inhibitor VAS2870 phenocopied the thyroid effects observed in duox or duoxa mutants. Additional functional in vitro assays corroborated the pharmacological inhibition of Duox activity by VAS2870. These data support the utility of this new experimental model to characterize endocrine disruptors of the thyroid function.

Immunomorphological Pattern of Molecular Chaperones in Normal and Pathological Thyroid Tissues and Circulating Exosomes: Potential Use in Clinics.

The thyroid is a major component of the endocrine system and its pathology can cause serious diseases, e.g., papillary carcinoma (PC). However, the carcinogenic mechanisms are poorly understood and clinical useful biomarkers are scarce. Therefore, we determined if there are quantitative patterns of molecular chaperones in the tumor tissue and circulating exosomes that may be useful in diagnosis and provide clues on their participation in carcinogenesis. Hsp27, Hsp60, Hsp70, and Hsp90 were quantified by immunohistochemistry in PC, benign goiter (BG), and normal peritumoral tissue (PT). The same chaperones were assessed in plasma exosomes from PC and BG patients before and after ablative surgery, using Western blotting. Hsp27, Hsp60, and Hsp90 were increased in PC in comparison with PT and BG but no differences were found for Hsp70. Similarly, exosomal levels of Hsp27, Hsp60, and Hsp90 were higher in PC than in BG, and those in PC were higher before ablative surgery than after it. Hsp27, Hsp60, and Hsp90 show distinctive quantitative patterns in thyroid tissue and circulating exosomes in PC as compared with BG, suggesting some implication in the carcinogenesis of these chaperones and indicating their potential as biomarkers for clinical applications.

Upregulated tissue expression of T helper (Th) 17 pathogenic interleukin (IL)-23 and IL-1ß in Hashimoto's thyroiditis but not in Graves' disease.

T helper (Th) 17 cells and interleukin (IL)-17 play a significant role in the pathogenesis of autoimmune thyroid disease (AITD). However, it has recently become clear that Th17 cells are more heterogeneous and exhibit two different phenotypes, whereas IL-23 and IL-1ß are crucial for the generation of pathogenic Th17 lymphocytes. We aimed to investigate the association between IL-17 and Th17-promoting cytokines in AITD by studying the immunoexpression patterns of IL-17, IL-23, and IL-1ß in thyroid tissue. Following thyroidectomy, 29 patients with AITD (21 cases of Hashimoto's thyroiditis (HT) and 8 cases of Graves' disease (GD)) and 18 patients with colloid goiter, as controls, were enrolled in this study, and immunohistochemistry was performed. The expression level of IL-17 in thyrocytes was significantly higher in HT and GD patients than in colloid goiter patients. Immunopositivity for both IL-23 and IL-1ß was significantly increased in HT patients compared to GD and colloid goiter patients. However, no difference was found between IL-23 or IL-1ß expression in patients with GD and colloid goiter. A positive correlation between IL-17 and IL-23 as well as IL-17 and IL-1ß expression was observed in HT patients (r = 0.574, p = 0.007 and r = 0.461, p = 0.036, respectively). In the GD group, IL-17 was positively correlated with IL-1ß (r = 0.817, p = 0.013) but not with IL-23 expression. We found increased IL-23 and IL-1ß expression in the HT group but not in the GD group. Furthermore, both interleukins were correlated with IL-17 immunopositivity in thyroid tissue, suggesting that pathogenic Th17-promoting cytokines may play a role in HT pathogenesis.

Type 1 and type 2 iodothyronine deiodinases in the thyroid gland of patients with huge goitrous Hashimoto's thyroiditis.

PURPOSE: The serum free triiodothyronine (FT3)/free thyroxine (FT4) ratio in patients with huge goitrous Hashimoto's thyroiditis (HG-HT) is relatively high. We investigated the cause of high FT3/FT4 ratios. METHODS: We measured the serum FT3, FT4, and thyrotropin (TSH) levels of seven patients with HG-HT who had undergone a total thyroidectomy. Eleven patients with papillary thyroid carcinoma served as controls. The activities and mRNA levels of type 1 and type 2 iodothyronine deiodinases (D1 and D2, respectively) were measured in the thyroid tissues of HG-HT and perinodular thyroid tissues of papillary thyroid carcinoma. RESULTS: The TSH levels in the HG-HT group were not significantly different from those of the controls. The FT4 levels in the HG-HT group were significantly lower than those of the controls, whereas the FT3 levels and FT3/FT4 ratios were significantly higher in the HG-HT group. The FT3/FT4 ratios in the HG-HT group who had undergone total thyroidectomy and received levothyroxine therapy decreased significantly to normal values. Both the D1 and D2 activities in the thyroid tissues of the HG-HT patients were significantly higher than those of the controls. However, the mRNA levels of both D1 and D2 in the HG-HT patients' thyroid tissues were comparable to those of the controls. Interestingly, there were significant correlations between the HG-HT patients' D1 and D2 activities, and their thyroid gland volume or their FT3/FT4 ratios. CONCLUSIONS: Our results indicate that increased thyroidal D1 and D2 activities may be responsible for the higher serum FT3/FT4 ratio in patients with HG-HT.

Socioeconomic status of the population - a prime determinant in evaluating iodine nutritional status even in a post salt iodization scenario.

Background To compare the state of iodine nutrition among school age children (SAC) in high- (HSGs) and low-socioeconomic groups (LSGs) during a post iodation scenario in Kolkata. Methods Clinical examinations of the goiter, median urinary iodine (MUI), mean urinary thiocyanate (MUSCN) in SAC (6-12 years) from both sexes in the different socioeconomic groups were carried out and the iodine content of edible salt was measured. Results A total of 5315 SAC, of which 2875 SAC were from a HSG and another 2440 SAC from an LSG were clinically examined for goiter. In the HSGs the total goiter prevalence (TGP) was 3.2% and in the LSGs the TGP was 9.1% and the difference was statistically significant (p<0.001). The MUI of the HSGs was 242 µg/L as compared to 155 µg/L in the LSGs (p<0.001). MUSCN of the HSGs was 0.77±0.45 mg/dL while in the LSGs it was 0.94±0.44 mg/dL and the difference was statistically significant (p<0.01). In the HSGs 19.4% salt samples had 15-30 ppm iodine and 80.6% salt samples were above 30 ppm as compared to 26.3% salt samples which were below 15 ppm, 37.1% salt samples which were between 15 and 30 ppm and 36.6% salt samples which were above 30 ppm in the LSGs. Conclusions The population of the LSGs was clinically mildly iodine deficient having no biochemical iodine deficiency while in the HSGs it was more than the adequate requirement and the HSG children are possibly at risk of excess iodine induced thyroid diseases. Existing goiter prevalence in the LSGs was from their relatively high consumption of dietary goitrogens. Therefore, socioeconomic status plays a pivotal role in the management of iodine nutrition even in a post salt iodation scenario.

TBX1 Functions as a Tumor Suppressor in Thyroid Cancer Through Inhibiting the Activities of the PI3K/AKT and MAPK/ERK Pathways.

BACKGROUND: TBX1 is a member of the T-box family of transcription factors characterized by a conserved DNA binding domain termed T-box. TBX1 has been reported to be downregulated in mouse skin tumors and is considered a negative regulator of tumor cell growth in mice. However, its role and exact mechanism in human cancers, including thyroid cancer, remain totally unknown. METHODS: Quantitative reverse transcription polymerase chain reaction and Western blot assays were performed to evaluate the expression of investigated genes. Methylation-specific polymerase chain reaction and pyrosequencing were used to analyze TBX1 promoter methylation. The biological functions of TBX1 in thyroid cancer cells were determined by a series of in vitro and in vivo experiments. Chromatin immunoprecipitation sequencing and dual-luciferase reporter assays were used to identify its downstream targets. RESULTS: This study demonstrates that TBX1 is frequently downregulated by promoter methylation in both papillary thyroid cancers and thyroid cancer cell lines. Ectopic expression of TBX1 in thyroid cancer cells dramatically inhibits cell viability, colony formation, and tumorigenic potential in nude mice, and induces cell-cycle arrest and apoptosis through modulating a panel of cell-cycle and apoptosis-related genes. In addition, ectopic expression of TBX1 significantly decreases the migration and invasion potential of thyroid cancer cells through inhibiting the process of epithelial-mesenchymal transition and the expression of matrix metalloproteinases. On the other hand, TBX1 knockdown markedly promotes thyroid cancer cell viability and invasiveness. Mechanistically, TBX1 exerts its tumor suppressor function in thyroid cancer cells through inhibiting phosphorylation of AKT at Ser473 and ERK via regulating its downstream targets such as RNF41, PARK2, and PHLPP2. CONCLUSIONS: The data show that TBX1 is frequently inactivated by promoter methylation and functions as a potential tumor suppressor in thyroid cancer through inhibiting the activities of the PI3K/AKT and MAPK/ERK signaling pathways.

Regulation of thyroid sodium-iodide symporter in different stages of goiter: Possible involvement of reactive oxygen species.

Na+ /I- symporter (NIS) transports iodide into thyrocytes, a fundamental step for thyroid hormone biosynthesis. Our aim was to evaluate NIS regulation in different status of goitrogenesis and its underlying mechanisms. Wistar rats were treated with methimazole (MMI) for 5 and 21 days, to achieve different status of goiter. We then evaluated the effect of MMI removal for 1 day (R1d), after 5 (R1d-5d) or 21 (R1d-21d) days of MMI treatment. MMI increased thyroid weight, iodide uptake and in vitro TPO activity in a time-dependent way. Although MMI removal evoked a rapid normalization of TPO activity in R1d-5d, it was still high in R1d-21d. On the other hand, iodide uptake was rapidly down-regulated in R1d-21d, but not in R1d-5d, suggesting that the increased TPO activity in R1d-21d led to increased intraglandular organified iodine (I-X), which is known to inhibit iodide uptake. Since TGFß has been shown to mediate some effects of I-X, we evaluated TGFß and TGFß receptor mRNA levels, which were increased in R1d-21d. Moreover, it has been demonstrated that TGFß stimulates NOX4. Accordingly, our data revealed increased NOX4 expression and H2 O2 generation in R1d-21d. Finally, we evaluated the effect of H2 O2 on NIS function and mRNA levels in PCCL3 thyroid cell line, which were reduced. Thus, the present study suggests that there is a relationship between the size of the goiter and NIS regulation and that the mechanism might involve I-X, TGFß, NOX4 and increased ROS production.

Expression level and clinical significance of IL-2, IL-6 and TGF-ß in elderly patients with goiter and hyperthyroidism.

OBJECTIVE: To investigate the level of expression and the clinical significance of IL-2 (interleukin-2), IL-6 (interleukin-6) and TGF-ß (transforming growth factor-ß) in elderly patients with goiter and hyperthyroidism. PATIENTS AND METHODS: Gender, age, course of disease, BMI (Body Mass Index), serum FT3 (Free triiodothyronine-3), FT4 (Free triiodothyronine-4), TT3 (Total triiodothyronine-3), TT4 (Total triiodothyronine-4), TSH (Thyroid Stimulating Hormone) and clinical manifestations on admission and other general clinical data and laboratory examination results were collected and statistically analyzed as case group in 128 elderly patients with goiter and hyperthyroidism. Additional 128 over 60-year-old patients with hyperthyroidism were selected as control group. The thyroid tissue of these patients and the control group were examined by fine needle aspiration biopsy. The expressions of IL-2, IL-6, TGF-ß of the thyroid tissue in all patients were detected by immunohistochemistry, qRT-PCR (Real-time Quantitative Polymerase Chain Reaction) and Western blot method respectively, and the statistical analysis was carried out. p < 0.05 indicated that the difference had statistical significance. RESULTS: Compared with the control group, the expressions of IL-2, IL-6 and TGF-ß in the group of patients were significantly higher (p < 0.05). The significantly higher expression of IL-2, IL-6, and TGF-ß was mainly concentrated in the thyroid follicular cells of patients with hyperthyroidism and thyroid enlargement (p < 0.05). In the patients with goiter, hyperthyroidism, and symptoms of exophthalmos, the level of expression of IL-6 was significantly higher than that of patients without exophthalmos (p < 0.05). In the patients with goiter, hyperthyroidism and symptoms of exophthalmos, and the patients with goiter, hyperthyroidism without symptoms of exophthalmos, IL-2 and TGF-ß expression level were not different (p > 0.05). CONCLUSIONS: The expression levels of IL-2, IL-6, and TGF-ß were significantly increased in the patients with senile goiter and hyperthyroidism, but in the senile patients with goiter, hyperthyroidism and exophthalmos symptoms, IL-6 levels were significantly higher than those without exophthalmos. The use of IL-2, IL-6, and TGF-ß is of great significance in the diagnosis of goiter with hyperthyroidism, especially for elderly patients with atypical clinical symptoms of hyperthyroidism.

GLIS3 is indispensable for TSH/TSHR-dependent thyroid hormone biosynthesis and follicular cell proliferation.

Deficiency in Krüppel-like zinc finger transcription factor GLI-similar 3 (GLIS3) in humans is associated with the development of congenital hypothyroidism. However, the functions of GLIS3 in the thyroid gland and the mechanism by which GLIS3 dysfunction causes hypothyroidism are unknown. In the current study, we demonstrate that GLIS3 acts downstream of thyroid-stimulating hormone (TSH) and TSH receptor (TSHR) and is indispensable for TSH/TSHR-mediated proliferation of thyroid follicular cells and biosynthesis of thyroid hormone. Using ChIP-Seq and promoter analysis, we demonstrate that GLIS3 is critical for the transcriptional activation of several genes required for thyroid hormone biosynthesis, including the iodide transporters Nis and Pds, both of which showed enhanced GLIS3 binding at their promoters. The repression of cell proliferation of GLIS3-deficient thyroid follicular cells was due to the inhibition of TSH-mediated activation of the mTOR complex 1/ribosomal protein S6 (mTORC1/RPS6) pathway as well as the reduced expression of several cell division-related genes regulated directly by GLIS3. Consequently, GLIS3 deficiency in a murine model prevented the development of goiter as well as the induction of inflammatory and fibrotic genes during chronic elevation of circulating TSH. Our study identifies GLIS3 as a key regulator of TSH/TSHR-mediated thyroid hormone biosynthesis and proliferation of thyroid follicular cells and uncovers a mechanism by which GLIS3 deficiency causes neonatal hypothyroidism and prevents goiter development.

Hypothyroidism associated with parathyroid disorders.

Hypothyroidism may occur in association with congenital parathyroid disorders determining parathyroid hormone insufficiency, which is characterized by hypocalcemia and concomitant inappropriately low secretion of parathormone (PTH). The association is often due to loss of function of genes common to thyroid and parathyroid glands embryonic development. Hypothyroidism associated with hypoparathyroidism is generally mild and not associated with goiter; moreover, it is usually part of a multisystemic involvement not restricted to endocrine function as occurs in patients with 22q11 microdeletion/DiGeorge syndrome, the most frequent disorders. Hypothyroidism and hypoparathyroidism may also follow endocrine glands' damages due to autoimmunity or chronic iron overload in thalassemic disorders, both genetically determined conditions. Finally, besides PTH deficiency, hypocalcemia can be due to PTH resistance in pseudohypoparathyroidism; when hormone resistance is generalized, patients can suffer from hypothyroidism due to TSH resistance. In evaluating patients with hypothyroidism and hypocalcemia, physical examination and clinical history are essential to drive the diagnostic process, while routine genetic screening is not recommended.