Excess iodine promotes apoptosis of thyroid follicular epithelial cells by inducing autophagy suppression and is associated with Hashimoto thyroiditis disease

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.

Tetrabromobisphenol A induces neuronal cytotoxicity by inhibiting PINK1-Parkin-mediated mitophagy via upregulating ATF3 expression

Tetrabromobisphenol A (TBBPA), as a widely used brominated flame retardant, has been implicated as a potential neurotoxicant. However, the mechanism of TBBPA-induced neurotoxicity has not been fully elucidated yet. In this study, using mouse hippocampal neuron cell HT22 as the in vitro model, the neuronal cytotoxicity of TBBPA and the mechanism by focusing on mitophagy have been studied. We found that neuronal cytotoxic effects were indeed induced by TBBPA exposure at concentrations of >20 μM for 24 h, including decreased cell viability (to 92.38 % at 20 μM; 18.25 % at 80 μM), enhanced ROS (enhanced 53.26 % at IC50 of 60 μM, compared with that in the control group) and mitochondrial ROS (mtROS) levels (enhanced 24.12 % at 60 μM), reduced mitochondrial membrane potential (MMP) (decreased 33.60 % at 60 μM). As a protective mechanism in cells, autophagy was initiated; however, mitophagy was inhibited, where PINK1 (PINK1-Parkin activation is critical in the depolarized MMP-induced mitophagy) expression was found to be repressed and decreased, further leading to the failure of Parkin recruitment to the damaged mitochondria. Mitophagy activator, nicotinamide mononucleotide (β-NMN) that activates the PINK1-Parkin pathway, could alleviate TBBPA-induced mitophagy deficiency and further reduce the neuronal cytotoxicity, demonstrating that TBBPA-induced PINK1-Parkin-mediated mitophagy deficiency contributed to the neuronal cytotoxicity. Furthermore, we found TBBPA caused the upregulation of Atf3 (activating transcription factor 3) gene transcription and expression levels, alongside reduced Pink1 levels; whereas enhanced Pink1 transcript levels were observed after ATF3 depletion even under TBBPA treatment, demonstrating TBBPA-induced overexpression of ATF3 should be responsible for the reduced PINK1 expression. Therefore, for the first time, here we demonstrate that TBBPA can inhibit PINK1-Parkin-mediated mitophagy via upregulating ATF3 expression, which further contributes to its neuronal cytotoxicity. This study should be able to improve our understanding of the mechanism of TBBPA-induced neuronal cytotoxicity.

Biological regulation on iodine using nano-starch for preventing thyroid dysfunction

The growing incidence of thyroid disease triggered by excess iodine uptake poses a severe health threat throughout the world. Extracellular interference therapies impede iodine transport across the sodium-iodide symporter (NIS) membrane protein and thus prevent excessive iodine uptake by thyroid cells, which may lessen the occurrence of disease. Herein, we for the first time utilized nano-starch particles (St NPs) to regulate iodine transport across the NIS protein of thyroid cells by using extracellular interference therapy. By precisely encapsulating iodine within the cavity of a glucan α-helix via hydrogen bonding, extracellular St NPs prevented excess iodine uptake by thyroid cells in vitro and in vivo; this down-regulated the expression of NIS protein (0.06-fold) and autophagy protein LC3B-II (0.35-fold). We also found that St NPs regulated the metabolic pathway of iodine in zebrafish. We believe this proposed strategy offers a novel insight into controlling iodine uptake by the thyroid and indicates a new direction for preventing iodine-induced thyroid disease.

Interaction between potassium iodide and bovine serum albumin, ovalbumin and lysozyme under different temperature induction

In this study, the interaction between potassium iodide and protein molecules under different temperature induction was studied, taking potassium iodide (KI) and protein molecules as a model system. The effects of KI on protein conformation, size, surface charge, binding constant, and binding site were analyzed by fluorescence spectrum, infrared spectrum, and diffusing wave spectroscopy. The results revealed that bovine serum albumin (BSA)/ovalbumin (OVA) and I-1 formed the 1: 1 complex and significantly affected the hydrodynamic radius and spatial structure. This could be attributed to the exposure of tyrosine residues inside the proteins to the polar conditions under increased temperature. The unfolding of protein structures induced the interaction between KI/KCl and proteins. As for BSA and OVA, the particle size and surface charge of the complex increased significantly in the presence of KI/KCl. KI had a strong static quenching effect on the fluorescence of BSA and OVA. Overall, these results provide insights into the physiological effects of iodine ions.

Thyroid hormones and minerals in immunocorrection of disorders in autoimmune thyroid diseases

Thyroid hormones and essential elements iodine (I), selenium (Se), iron (Fe), copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), etc. play an important role in the work of many organs and systems of the body, including the immune system and the thyroid gland, and a violation of their supply can be the cause of pathological changes in them. In pathology, the interaction between thyroid hormones (TG), minerals and the immune system is disturbed. The review of the literature examines the immunomodulatory role of TG, minerals, their properties, and their participation in the pathogenesis of autoimmune thyroid diseases (AITD). The study of the relationship between the excess or deficiency of minerals and AITD is described. The basis of the development of AITD - Hashimoto's thyroiditis (HT), Graves' disease (GD), Graves' ophthalmopathy (GO) is the loss of immune tolerance to thyroid antigens - thyroid peroxidase (TPO), thyroglobulin (Tg) and thyroid-stimulating hormone receptor (TSH-R). Immune-mediated mechanisms - production of autoantibodies to thyroid antigens and lymphocytic thyroid infiltration - are involved in the pathogenesis of AITD. Insufficiency of regulatory T cells (Treg) and regulatory B cells (Breg), imbalance between Th17-lymphocytes and Treg-lymphocytes, abnormal production of pro-inflammatory cytokines has a significant influence on the progression of AITD. With AITD, the balance between oxidants and antioxidants is disturbed and oxidative stress (OS) occurs. The lack of modern effective pharmacological therapy of AITD prompted us to consider the mechanisms of influence, possibilities of immunocorrection of pathogenetic factors using TG, micro/macronutrients. In order to develop a more effective treatment strategy, as well as approaches to prevention, a critical analysis of the ways of immunotherapeutic use of dietary supplements of I, Se, Zn, Mg and other minerals in AITD was carried out.

Excessive iodine induces thyroid follicular epithelial cells apoptosis by activating HIF-1α-mediated hypoxia pathway in Hashimoto thyroiditis

BACKGROUND

Hashimoto thyroiditis (HT) is considered the most common autoimmune thyroid disease. A growing body of evidence suggests that HT incidence correlates with excessive iodine intake. We should probe the effects of excessive iodine intake in HT development and its possible mechanism.

METHODS AND RESULTS

The study recruited 20 patients: 10 with HT and 10 with nodular goiter. We detected the expression of an apoptosis-related protein caspase-3 by immunohistochemistry. In vitro study, we explored the proliferation and apoptosis status in thyroid follicular cells (TFCs) stimulated with different iodine concentrations by MTT and flow cytometry. Then we performed RNA sequence analysis of Nthy-ori3-1 cells treated for 48 h with KI to probe the underlying mechanism. Finally, we used RT-PCR and siRNA interference to verify the results. We identified apoptosis in thyroid tissue obtained from HT patients coincides with the increase of caspase-3 levels. In vitro study, iodine suppressed proliferation of TFCs and promoted TFCs apoptosis in a dose-dependent manner with regulating caspase-3 activation. HIF-1α-NDRG1 mediated hypoxia pathway activation promoted the transmission of essential apoptosis signals in TFCs.

CONCLUSION

Our study confirmed that excessive iodine adsorption activates the HIF-1α-mediated hypoxia pathway to promote apoptosis of TFCs, which may be an important risk factor contributing to HT development.

The role behind the scenes of Tregs and Th17s in Hashimoto's thyroiditis: Toward a pivotal role of FOXP3 and BACH2

In Hashimoto's thyroiditis (HT), the genetic bases play a central role in determining development of the disease. In particular, the most frequent genes involved in the onset of HT are the Human Leukocyte Antigen (HLA). However, there are other genes and transcription factors in the autoimmune background of HT, both isolated and as part of autoimmune polyendocrine syndromes (APS). Recently more interest is being fueled toward BACH2 (BTB Domain and CNC Homolog 2), that promotes Tregs (T regulators lymphocytes) differentiation and enhances Treg-mediated immunity. The synergistic interaction between environmental agents and the aforementioned genes leads to the onset of autoimmunity and ultimately to damage of the thyroid gland. In this scenario, the role of Th17 (T helper-17 lymphocytes) and Treg cells is still less defined as compared to action of Th1 cells (T helper-1 lymphocytes) and cytotoxic lymphocytes (CD8 ⁺ T lymphocytes). Evidences show that an imbalance of Th17/Treg ratio represents a prognostic factor with respect to the gland damage. Moreover, the deficient ability of Treg to inhibit the proliferation of T cells against the self can break the immune balance. In light of these considerations, the use of genetic panels and the progress of immunotherapy could allow for better targeting treatment and preventive interventions in subjects with potential or early stage of HT.

Effects of herbal cake-partitioned moxibustion on the expression of thyroid autophagy-related factors LC3B and Beclin-1 in rats with autoimmune thyroiditis

Objective

To observe the anti-inflammatory effect, as well as the effect on the expression of microtubule-associated protein light chain 3B (LC3B) and Beclin-1 of herbal cake-partitioned moxibustion in rats with experimental autoimmune thyroiditis (EAT).

Methods

Female Sprague-Dawley rats were randomly divided into a normal group and a modeling group. The EAT rat model was prepared by a combination of antigen immunization plus iodine agent induction. After the model was prepared, rats in the modeling group were randomly and equally divided into a model group and a herbal cake-partitioned moxibustion group. In the herbal cake-partitioned moxibustion group, moxibustion was alternately applied to two groups of points [Dazhui (GV14)-Mingmen (GV4) and Tiantu (CV22)-Guanyuan (CV4)], and the treatment continued for 30 d. Rats in the normal and model groups were only fixed identically without intervention. Histopathological manifestations of thyroid glands were observed by hematoxylin-eosin staining; the concentrations of thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TGAb), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay; real-time fluorescence quantitative polymerase chain reaction and immunohistochemistry were used to detect the mRNA and protein expression of autophagy-related factors LC3B and Beclin-1 in thyroid tissue.

Results

There were massive follicular destruction, lymphocytic infiltration, and interstitial fibrous tissue hyperplasia of the thyroid glands in the model group. Some follicles of the thyroid glands were destroyed with few lymphocyte infiltrations and fibrous tissue hyperplasia in the moxibustion group. Compared with the normal group, the concentrations of serum TPOAb, TGAb, IL-1β, IL-6, and TNF-α were increased in the model rats (P<0.05); the mRNA and protein expression levels of LC3B and Beclin-1 in thyroid tissue were reduced in the model group (P<0.05). Compared with the model group, the concentrations of serum TPOAb, TGAb, IL-1β, IL-6, and TNF-α were reduced in the herbal cake-partitioned moxibustion group (P<0.05); the mRNA and protein expression levels of LC3B and Beclin-1 in thyroid tissue were increased in the herbal cake-partitioned moxibustion group (P<0.05). The mRNA and protein expression of LC3B and Beclin-1 in thyroid tissue was negatively correlated with the serum levels of TPOAb and TGAb.

Conclusion

Herbal cake-partitioned moxibustion reduces the inflammatory response in the thyroid glands of EAT rats and lowers the levels of serum TPOAb and TGAb. This may be related to the regulation of mRNA and protein expression of the autophagy-associated factors LC3B and Beclin-1 in rat thyroid tissue.

Mediterranean Diet and Thyroid: An Interesting Alliance

The Mediterranean diet, recognized as being cultural heritage by UNESCO, is mostly plant-based and includes a high consumption of whole-grain, fruit, and vegetables with a moderate consumption of alcohol during meals. Thus, it provides a small amount of saturated fatty acids and a high quantity of antioxidants and fiber. For this reason, it has been considered to have an important role in preventing cardiovascular diseases, chronic kidney diseases, type 2 diabetes mellitus, and cancer, but its relationship with thyroid function and diseases is still under debate. The aim of this review was to search for the possible correlation between the Mediterranean diet and thyroid function, and to critically evaluate the pathophysiological link between selected food intake and thyroid disorders.

Decreased β-catenin expression contributes to IFNγ-induced chemokine secretion and lymphocyte infiltration in Hashimoto's thyroiditis

Hashimoto's thyroiditis (HT) is a very common organ-specific autoimmune disease characterized by lymphocyte infiltration and the destruction of thyroid follicular cells (TFCs), in which IFN-γ and chemokines play pivotal roles. Moreover, β-catenin has been implicated in the regulation of T cell infiltration. However, whether β-catenin is involved in Hashimoto's thyroiditis is unknown. Here, we examined β-catenin expression in thyroid tissues and investigated its role in the pathogenesis of HT. The results showed that β-catenin expression was markedly reduced in the thyroid tissues of HT patients; more importantly, IFN-γ treatment markedly reduced the expression of β-catenin and was accompanied by the secretion of chemokines such as CCL5, CXCL16, GRO-β, and GRO-γ in TFCs in vitro, which was attributed to GSK-3β/β-catenin signaling pathway activation. Collectively, the decreased expression of β-catenin might contribute to IFNγ-induced chemokine secretion and lymphocyte infiltration in the development of HT.

Nickel Sulfate Induces Autophagy in Human Thyroid Follicular Epithelial Cells

Nickel is an industrial and environmental toxic metal, which is toxic to humans in certain forms at high doses. Here, we investigated the cytotoxic effects of nickel sulfate (NiSO₄) exposure on the human thyroid follicular epithelial cells (Nthy-ori 3-1) and its underlying toxicological mechanisms. The results showed that NiSO₄ reduced the cell viability of Nthy-ori 3-1 cells in a dose- and time-dependent manner, inducing S and G2/M phases cell-cycle arrest and apoptosis. Electron microscopy demonstrated that abundant autophagic vacuoles were found in Nthy-ori 3-1 cells after NiSO₄ treatment. Accordingly, exposure of Nthy-ori 3-1 cells to NiSO₄ resulted in a dose-dependent increase of LC3II/I ratio, an induction of Beclin-1 expression, and a decrease in p62 levels. Blockade of autophagy with 3-methyladenine (3-MA) potentiated the NiSO₄-induced apoptotic cell death, while induction of autophagy significantly alleviated toxicity of NiSO₄. From a molecular standpoint, NiSO₄ markedly promoted the activation of p38 and IKKβ by increasing their phosphorylation. In conclusion, we showed that autophagy was induced to protect thyroid cells from Ni²⁺ mediated apoptosis, thus providing rational strategy to prevent against nickel toxicity in the thyroid.

Proteomics and Organoid Culture Reveal the Underlying Pathogenesis of Hashimoto's Thyroiditis

Hashimoto’s thyroiditis (HT) is an autoimmune disease, and its incidence continues to rise. Although scientists have studied this disease for many years and discovered the potential effects of various proteins in it, the specific pathogenesis is still not fully comprehended. To understand HT and translate this knowledge to clinical applications, we took the mass spectrometric analysis on thyroid tissue fine-needle puncture from HT patients and healthy people in an attempt to make a further understanding of the pathogenesis of HT. A total of 44 proteins with differential expression were identified in HT patients, and these proteins play vital roles in cell adhesion, cell metabolism, and thyroxine synthesis. Combining patient clinical trial sample information, we further compared the transient changes of gene expression regulation in HT and papillary thyroid carcinoma (PTC) samples. More importantly, we developed patient-derived HT and PTC organoids as a promising new preclinical model to verify these potential markers. Our data revealed a marked characteristic of HT organoid in upregulating chemokines that include C-C motif chemokine ligand (CCL) 2 and CCL3, which play a key role in the pathogenesis of HT. Overall, our research has enriched everyone’s understanding of the pathogenesis of HT and provides a certain reference for the treatment of the disease.

Clinical Studies on Potassium Iodide-induced Painless Thyroiditis in 11 Graves' Disease Patients

Objective Painless thyroiditis (PT) is characterized by transient hyperthyroidism with a low ^99mTc uptake. We herein describe 11 cases of PT that occurred during treatment with potassium iodide (KI) for Graves' disease (GD). Methods From August 2016 to December 2018, 11 women with GD who developed PT during treatment with KI were enrolled. Of these patients, 10 discontinued antithyroid drug (ATD) because of side effects and began KI, and 1 patient switched from thiamazole to KI because she was planning a pregnancy. The mean patient age was 40.1 years old. Thyroid function tests, thyroid autoantibodies including anti thyroglobulin antibody (TgAb), anti-thyroperoxidase antibody (TPOAb), and M22-TRAb, and the ^99mTc uptake were evaluated at the time of PT. Results All 11 women patients presented with transient thyrotoxicosis in which ^99mTc scans revealed a low uptake of 0.34±0.15% (normal 0.70-1.02%). M22-TRAb was absent in all cases except for one (2.4 IU/L), whereas TgAb and TPOAb were present in 10 and 6 cases, respectively. Ten patients returned to a euthyroid status without passing through the post-hypothyroid phase, and one patient underwent total thyroidectomy during the euthyroid phase of PT. Only four patients require beta-blocker therapy. All patients with KI-induced PT except 1 displayed GD remission during a mean observation period of 23.3 months, and 1 patient had recurrence of GD after PT. Conclusion We encountered 11 GD patients who developed PT during treatment with KI, which was initiated after ATD had been discontinued due to side effects.

Long-term Observation of Thyroid Volume Changes in Hashimoto's Thyroiditis in a Series of Women on or off Levo-Thyroxine Treatment in an Area of Moderate Iodine Sufficiency

CONTEXT

Large variations in thyroid volume (TV) have been reported in Hashimoto's thyroiditis (HT). The need for long-term levo-thyroxine (L-T4) administration in order to control TV, as well as to normalise thyroid function, has not been well defined.

SUBJECTS AND METHODS

Retrospective data on TV in 94 adult women with HT were analysed in an ambulatory setting in Liguria, an area of moderate iodine sufficiency. TV was evaluated by means of ultrasonography (US). Thyroid function, anthropometric data, smoking habits and pharmaceutical drugs were registered at each examination.

RESULTS

At the baseline, an atrophic gland was noted in 16% of the women, and goitre in 13%. The women were evaluated 56 and 102 months after the baseline examination. At the time of each examination, 50%, 78% and 83% of women, respectively, were on L-T4 treatment. Baseline TV was not significantly different in women on/off L-T4 treatment. However, in those on L-T4, TV decreased significantly over the period of follow-up, while in those without L-T4 treatment, it did not change. By the end of the study, the percentage of L-T4-treated women with an atrophic gland had increased to 27%, and that of women with goitre had dropped to 6%; in untreated women, only minor changes were noted. There was a significant negative correlation between TV% change and baseline TSH levels in HT women on L-T4 treatment.

CONCLUSION

The majority of HT women living in an area of moderate iodine sufficiency have normal TV. Moreover, long-term L-T4 treatment can be used to control TV, as well as to maintain normal thyroid parameters.

Relationship between Gene Polymorphisms and Urine Iodine Levels on Susceptibility to Thyroid Peroxidase Antibody Positivity in the Chinese Population

BACKGROUND/AIMS

Hashimoto thyroiditis, characterized by positive thyroid peroxidase antibodies (TPOAbs), is caused by the interaction of genetic and environment factors. The aim of this study was to clarify the interaction of gene polymorphisms and iodine intake in the incidence of TPOAb positivity.

METHODS

1,733 subjects were included in this study. Genomic DNA was extracted from peripheral blood white cells. Four SNPs (rs11675434 [TPO], rs3094228 [HCP5], rs9277555 [HLA-DPB1], and rs301799 [RERE]) were selected for genotyping. Weighted TPOAb genetic risk score (GRS) was calculated based on these 4 SNPs. Thyroid hormones and autoimmune antibodies (TPOAb and thyroglobulin antibody) were determined using the electrochemiluminescence immunoassay method.

RESULTS

The mean serum thyrotropin level in TPOAb-positive subjects was higher than in TPOAb-negative subjects (p < 0.01). Genotype GG of rs9277555 was associated with an increased risk of TPOAb positivity (OR = 1.64, 5-95% CI 1.09, 2.47, p = 0.02). Genotype TT of rs11675434 showed marginal increased risk of TPOAb positivity (OR = 1.57, 5-95% CI 1.01, 2.43, p = 0.048). Logistic regression analysis showed TPOAb-GRS and rs9277555 were associated with TPOAb positivity (OR = 5.09, 5-95% CI 1.30, 19.91, p = 0.02 and OR = 1.30, 5-95% CI 1.05, 1.61, p = 0.02). Subjects with a high TPOAb-GRS had a 52% increased risk of TPOAb positivity compared to subjects with a low TPOAb-GRS (OR 1.52, 5-95% CI 1.05, 2.21, p = 0.03).

CONCLUSION

TPOAb-GRS was associated with an increased risk of TPOAb positivity in a Chinese Han population. This effect might be attribute to rs9277555.

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

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.

Association between excessive chronic iodine exposure and the occurrence of papillary thyroid carcinoma

The aim of the present study was to elucidate the association between excessive chronic iodine exposure and the risk of developing papillary thyroid carcinoma (PTC). The demographic information and pathological characteristics of patients with thyroid nodules were retrieved from medical records at The Second Hospital of Shandong University. A fasting urine specimen was collected, and creatinine and urinary iodine concentration (UIC) were determined. The water iodine data from the domicile districts of these patients were collated from published reports. The results revealed that almost half of the patients with PTC (44.3%) also exhibited a high UIC (≥300 µg/l). Multivariate analysis revealed that the adjusted odds ratio for high UIC was 3.987 (95% CI: 1.355–11.736) and the adjusted area under the receiver operating characteristic curve was 0.776 (95% CI: 0.687–0.864), which was associated with PTC risk in patients with thyroid nodules. Integrated ecological assessment of chronic iodine exposures demonstrated that >80% (81.4%) of the patients with PTC who also exhibited a high UIC were from historically non-iodine-deficient regions, and 66.7% of patients with PTC who resided in historically iodine-excessive regions were characterized by high UICs. Importantly, a high UIC was significantly associated with capsular invasion and extrathyroid metastasis (P<0.05). Moreover, self-matching results indicated that, in patients with PTC, there were no significant differences in UIC grading between the pre- and postoperative specimens. In conclusion, excessive chronic iodine exposure is significantly associated with the risk of PTC, which contributes to increased capsular invasion and extrathyroid metastases. However, further research is required to validate these findings and to elucidate the potential molecular mechanisms involved.

Hormonal Regulation of Autophagy in Thyroid PCCL3 Cells and the Thyroids of Male Mice

Autophagy is an evolutionarily conserved catabolic process by which cells degrade intracellular proteins and organelles in the lysosomes and recycle their metabolites. We have recently demonstrated the crucial role for the basal level of autophagic activity in thyrocyte survival and homeostasis using the thyroid-specific autophagy knockout mice. Here, we first studied hormonal regulation of autophagy in thyrocytes in vitro using a rat thyroid cell line PCCl3 and in vivo with mice. In cultured PCCl3 cells, thyroxine decreased microtubule-associated protein 1 light chain 3 (LC3) puncta (a component of autophagosome) and increased p62 (an autophagy substrate) levels, showing thyroxine-suppression of autophagy. In contrast, TSH increased both LC3 puncta and p62 levels, but at the same time stabilized p62 protein by inhibiting p62 degradation, indicating TSH induction of autophagy. Our experiments with various inhibitors identified that both the cAMP-protein kinase (PK) A-cAMP response element binding protein/ERK and PKC signaling pathways regulates positively autophagic activity. The in vivo results obtained with wild-type mice treated with methimazole and perchlorate or thyroxine were consistent with in vitro results. Next, in thyroid-specific autophagy knockout mice treated with methimazole and perchlorate (that is, mice were placed under a stressed condition where enhanced autophagy was required) for 2 months, lower follicle sizes and lower thyroglobulin contents in thyrocytes were observed, suggesting impaired thyroglobulin production presumably from insufficient nutrient supply. We therefore conclude that TSH positively regulates autophagic activity through the cAMP-PKA-cAMP response element binding protein/ERK and PKC signaling pathways, whereas thyroid hormones inhibit its activity in thyrocytes. Metabolites produced by autophagy appear to be necessary for protein synthesis stimulated by TSH.

Excess iodine impairs spermatogenesis by inducing oxidative stress and perturbing the blood testis barrier

Approximately 2 billion people worldwide are susceptible to iodine deficiency. Iodine deficiency has largely been tackled by iodine fortification in salt; however indiscriminate use of iodine raises the risk of iodine toxicity. In this study, we aimed to investigate the molecular mechanisms underlying adverse effect of excess iodine on spermatogenesis. Sprague Dawley (SD) rats were orally administered with 0.7 mg potassium iodide (KI)/100 g Bw and 3.5 mg potassium iodide (KI)/100 g Bw for a period of 60 days. This resulted in significant loss of sperm count and motility. Molecular investigations provided evidence for the generation of oxidative stress with high SOD levels, reduced Nrf2, HO-1 and increased NF-kB and Follistatin. Further investigations showed increased apoptosis evidenced by reduced expression of anti-apoptotic (BCL-2, Survivin), increased expression of pro-apoptotic (Bid, Bax) markers, and increased expression of p53 and other modulators/effectors of apoptosis (cytochrome c, cleaved PARP, caspase3 and caspase9). Analysis of the blood testis barrier proteins showed reduced expression of tight junction (JAM-A, Tricellulin), ectoplasmic specialization (Integrin- β1), adherens junction (N-Cadherin, E-cadherin, β-catenin) proteins, and reduced expression of other junction protein coding genes (Claudin1, Claudin 5, Occludin, ZO-1, Testin, Fibronectin, CAR-F). Focal adhesion kinase (FAK) and key regulators of spermatogenesis (c-Kit receptor, androgen receptor) were also parallelly decreased. Further investigation showed reduced expression of germ cell proliferation and differentiation markers (PCNA, Cyclin D1, c-Kit, Cdk-4). These findings collectively explain the loss of spermatogenesis under excess iodine conditions. In conclusion, excess iodine causes loss of spermatogenesis by inducing oxidative stress and disrupting the blood testis barrier and cytoskeleton.

AATF and SMARCA2 are associated with thyroid volume in Hashimoto's thyroiditis patients

Thyroid volume of Hashimoto’s thyroiditis (HT) patients varies in size over the course of disease and it may reflect changes in biological function of thyroid gland. Patients with subclinical hypothyroidism predominantly have increased thyroid volume whereas patients with more pronounced hypothyroidism have smaller thyroid volumes. Suggested mechanism for thyroid atrophy is thyrocyte death due to apoptosis. We performed the first genome-wide association study (GWAS) of thyroid volume in two groups of HT patients, depending on levothyroxine (LT4) therapy, and then meta-analysed across. Study included 345 HT patients in total and 6 007 322 common autosomal genetic variants. Underlying hypothesis was that genetic components that are involved in regulation of thyroid volume display their effect in specific pathophysiologic conditions of thyroid gland of HT patients. We additionally performed immunohistochemical analysis using thyroid tissues and analysed differences in expression levels of identified proteins and apoptotic marker between HT patients and controls. We found genome-wide significant association of two loci, both involved in apoptosis, with thyroid volume of HT patients: rs7212416 inside apoptosis-antagonizing transcription factor AATF (P = 8.95 × 10⁻⁹) and rs10738556 near chromatin-remodeling SMARCA2 (P = 2.83 × 10⁻⁸). In immunohistochemical analysis we observed that HT patients with homozygous AATF risk genotypes have decreased AATF expression (0.46-fold, P < 0.0001) and increased apoptosis (3.99-fold, P = 0.0001) in comparison to controls. HT patients with heterozygous SMARCA2 genotypes have decreased SMARCA2 expression, albeit without reaching statistical significance (1.07-fold, P = 0.5876), and significantly increased apoptosis (4.11-fold, P < 0.0001). By two lines of evidence we show that two highly plausible genetic loci, AATF and SMARCA2, may be involved in determining the thyroid volume of HT patients. The results of our study significantly add to the current knowledge of disturbed biological mechanisms in thyroid gland of HT patients.

Caveolin-1 Regulates CCL5 and PPARγ Expression in Nthy-ori 3-1 Cells: Possible Involvement of Caveolin-1 and CCL5 in the Pathogenesis of Hashimoto's Thyroiditis

BACKGROUND

Hashimoto's thyroiditis (HT) is characterized by lymphocytic infiltration of the thyroid parenchyma, which ultimately leads to tissue destruction and loss of function. Caveolin-1 (Cav-1) is an essential structural constituent of lipid rafts in the plasma membrane of cells and is reported to be significantly reduced in thyrocytes from HT patients. However, the mechanism of Cav-1 involvement in HT pathogenesis is still largely unclear.

METHODS

Cav-1 expression in thyroid tissues from HT patients and euthyroid nodular goiter tissues was detected by immunohistochemistry staining. Cav-1 knockdown and overexpression were constructed by lentiviral transfection in the human thyroid follicular epithelial cell (TFC) line of Nthy-ori 3-1. The mRNA expression levels of chemokines in TFCs were determined by quantitative real-time PCR (qPCR). Cav-1 and peroxisome proliferator-activated receptor gamma (PPARγ) levels were analysed by qPCR and Western blot analysis. The migration ability of peripheral blood mononuclear cells (PBMCs) was detected by the Transwell assay.

RESULTS

In this study, Cav-1 and PPARγ expression was reduced in the thyroid tissues from HT patients. In vitro experiments showed that the expressions of chemokine (C-C motif) ligand 5 (CCL5) and migration of PBMCs were markedly increased, while the level of PPARγ was significantly decreased after the lentivirus-mediated knockdown of Cav-1 in Nthy-ori 3-1 cells. Interestingly, pioglitazone, a PPARγ agonist, not only upregulated PPARγ and Cav-1 proteins significantly, but also effectively reversed the Cav-1-knockdown-induced upregulation of CCL5 in Nthy-ori 3-1 cells and reduced the infiltration of lymphocytes.

CONCLUSION

The inhibition of Cav-1 upregulated the CCL5 expression and downregulated the PPARγ expression in TFC while pioglitazone, a PPARγ agonist, reversed the detrimental consequence. This outcome might be a potential target for the treatment of lymphocyte infiltration into the thyroid gland and HT development.

Genetic Polymorphisms on 4q21.1 Contributed to the Risk of Hashimoto's Thyroiditis

Background: Hashimoto's thyroiditis (HT) is a common autoimmune disease characterized by lymphoid infiltration of the thyroid gland, including both T- and B-cells. Early studies have shown that HT is a complex disorder affected by both environmental and genetic factors. Recently, the single nucleotide polymorphism (SNP) rs2276886 associated with the CXCL9 gene was identified as associated with autoimmune thyroid disease susceptibility in Japanese populations. The aim of the present study was to validate this result for HT in a Chinese Han population. Methods: Study subjects, including 688 HT cases and 1456 healthy controls, were recruited, and 10 SNPs located within the CXCL9 gene were genotyped. Genetic association analyses were performed by fitting logistic models. Bioinformatics tools, including RegulomeDB and GTEx were utilized to investigate the functional consequences of the SNPs found to be significantly associated with HT. Results: SNP rs2276886 was identified as significantly associated with the risk of HT (odds ratio [OR] = 1.25, p = 0.0006). No significant expression quantitative trait loci (eQTL) signals could be identified for CXCL9. Significant eQTL signals were found for other genes, including ART3, CXCL10, CXCL11, NAAA, PPEF2, and SCARB2. This SNP physically maps to the CXCL9 gene region; however, further bioinformatic analyses indicated that this SNP might be associated with the gene NAAA. Conclusions: The rs2276886 SNP was found to be significantly associated with HT susceptibility. However, our findings suggest that this SNP which maps to the chromosomal region 4q21.1 likely effects the NAAA gene (as opposed to the CXCL9 gene), but still contributes to the susceptibility to HT in Han Chinese populations.

Basal Autophagy Deficiency Causes Thyroid Follicular Epithelial Cell Death in Mice

Autophagy is a catabolic process that involves the degradation of cellular components through the lysosomal machinery, relocating nutrients from unnecessary processes to more pivotal processes required for survival. It has been reported that systemic disruption of the Atg5 or Atg7 gene, a component of autophagy, is lethal and that its tissue-specific disruption causes tissue degeneration in several organs. However, the functional significance of autophagy in the thyroid glands remains unknown. Our preliminary data imply the possible involvement of dysfunctional autophagy in radiation-induced thyroid carcinogenesis. Therefore, we evaluated the effect of Atg5 gene knockout (KO) on thyroid morphology and function. To this end, Atg5flox/flox mice were crossed with TPO-Cre mice, yielding the thyroid follicular epithelial cell (thyrocyte)‒specific ATG5-deficient mice (Atg5thyr-KO/KO). Atg5 gene KO was confirmed by a lack of ATG5 expression, and disruption of autophagy was demonstrated by a decrease in microtubule-associated protein 1 light chain 3-II puncta and an increase in p62. Atg5thyr-KO/KO mice were born normally, and thyroid morphology, thyroid weights, and serum T4 and TSH levels were almost normal at 4 months. However, at 8 and 12 months, a decrease in the number of thyrocytes and an increase in TUNEL+-thyrocytes were observed in Atg5thyr-KO/KO mice even though thyroid function was still normal. The number of irregularly shaped (gourd-shaped) follicles was also increased. Excess oxidative stress was indicated by increased 8-hydroxy-2'-deoxyguanosine and 53BP1 foci in Atg5thyr-KO/KO mice. These data demonstrate that thyrocytes gradually undergo degradation/cell death in the absence of basal levels of autophagy, indicating that autophagy is critical for the quality control of thyrocytes.

Sphk1/S1P/S1PR1 Signaling is Involved in the Development of Autoimmune Thyroiditis in Patients and NOD.H-2h4 Mice

Background: There is growing evidence that sphingosine-1-phosphate (S1P), a pleiotropic bioactive sphingolipid metabolite synthesized intracellularly by two closely related sphingosine kinases (SphKs), SphK1 and SphK2, is involved in inflammation. However, the role of SphKs/S1P/S1P receptors (S1PRs) in autoimmune thyroiditis (AIT) has not been studied to date. Methods: This study examined whether SphK1/S1P/S1PR1 signaling is aberrantly altered in thyroid tissues and serum of both AIT patients and a spontaneously autoimmune thyroiditis (SAT) mouse model. Murine CD4+T cells were employed to further investigate the downstream signaling of SphK1/S1P/S1PR1. Furthermore, a total of 102 NOD.H-2^h4 mice, randomly divided into different groups, were used to investigate the therapeutic effect of S1PR1 blockade and its potential mechanism. Results: We found that components of the SphK1/S1P/S1PR1 pathway were abnormally expressed in patients with Hashimoto thyroiditis and in a SAT mouse model. In addition, S1P could activate signal transducer and activator of transcription 3 (STAT3) through S1PR1 and its downstream signaling pathways in CD4+T cells of NOD.H-2^h4 mice. Furthermore, an in vivo study demonstrated that blocking S1PR1 by FTY720 administration could reduce the incidence and severity of thyroiditis and goiter in SAT mice in a time-dependent manner. The proportions of STAT3-related and inflammation-related cell subtypes, such as T helper 1, T helper 17, and follicular T helper cells, were elevated in the SAT group when compared to the control group, and these cell subtypes decreased after FTY720 administration. Furthermore, the downstream inflammatory cytokines of STAT3 were also downregulated after FTY720 administration. Conclusion: The present study shows that blocking Sphk1/S1P/S1PR1 signaling can ameliorate the severity of AIT, providing evidence of a promising therapeutic target for AIT.

2,3',4,4',5-Pentachlorobiphenyl induced autophagy of the thyrocytes via DAPK2/PKD/VPS34 pathway

2,3',4,4',5-Pentachlorobiphenyl (PCB118) has been shown to cause thyroidal ultrastructure lesions, but the underlying mechanism remains elusive. This study aimed to elucidate the mechanism by which PCB118 induces the abnormalities of the thyrocytes. Wistar rats were injected intraperitoneally with PCB118 (0, 10, 100 and 1000 μg/kg/d) for 13 weeks, and FRTL-5 cells were treated with PCB118 (0, 0.25, 2.5 and 25 nM). Transmission electron microscopy showed typical autophagosomes in the thyroid of PCB118-treated rats. Immunofluorescence staining showed dose-dependent increase of autophagy in FRTL-5 cells exposed to PCB118. In vivo and vitro studies found that Tubulin beta 3 class III (Tubb3) mRNA and protein levels decreased significantly, while Death-associated protein kinase 2 (DAPK2) increased after PCB118 exposure, and the binding between Tubb3 and DAPK2 was enhanced by PCB118 in a dose-dependent manner. Moreover, PCB118 resulted in the upregulation of Protein kinase D (PKD) and downregulation of Phosphatidylinositol 3-kinase (VPS34) in mRNA levels, and the activation of PKD and VPS34 phosphorylation. Additionally, Tubb3 small interfering RNA (siTubb3) suppressed DAPK2 protein expression and PKD phosphorylation in FRTL-5 cells, while VPS34 phosphorylation was inhibited by siPKD. Furthermore, DAPK2, PKD and VPS34 were upregulated by Tubb3 overexpression following PCB118 exposure. Our results demonstrate that low concentrations of PCB118 could promote thyroid autophagy formation and cause the abnormalities in thyroidal ultrastructure, and these effects are likely to be mediated by DAPK2/PKD/VPS34 dependent pathway.

Rheumatoid arthritis and thyroid dysfunction: A cross-sectional study and a review of the literature

Thyroid dysfunction appears to show increased prevalence in many autoimmune diseases; however, this comorbidity has not been properly investigated in patients with RA. This issue was addressed in this cross-sectional study. Using the database of the Clalit Health Services (CHS) in Israel, RA patients were paired with age- and sex-matched controls to compare the prevalence of hypothyroidism and hyperthyroidism. Chi-squared and t-tests were used for univariate analysis and a logistic regression model was used for multivariate analysis. The study included 11,782 patients with RA and 57,973 controls. The rate of thyroid dysfunction diseases in RA patients was increased compared with the prevalence in controls (16.0% and 11.7%, p < 0.001, for hypothyroidism; and 2.33% and 1.81%, p < 0.001 in hyperthyroidism, respectively). In a multivariate analysis, RA was associated with hypothyroidism (OR = 1.42, 95% CI 1.34-1.50) and hyperthyroidism (OR = 1.26, 95% CI 1.10-1.45). RA is associated with thyroid dysfunction. Therefore, physicians treating patients with RA should be aware of the possibility of comorbid thyroid dysfunction and treat accordingly.

miRNA-125a modulates autophagy of thyroiditis through PI3K/Akt/mTOR signaling pathway

The present study examined the potential function and underlying mechanisms of microRNA-125a (miR-125a) in thyroiditis. Mice were subcutaneously administered with 100 µg porcine thyroglobulin weekly for 2 weeks to establish the thyroiditis model. Results of the in vivo study demonstrated that miR-125a serum expression was upregulated in thyroiditis mice compared with the control group. In vitro studies were performed on a mouse macrophage cell line in which a model of thyroiditis was established using 10 ng/ml human interferon-γ. Upregulated miR-125a expression was achieved via mimic transfection. Increased miR-125a expression reduced autophagy and cell proliferation, increased the apoptotic rate and the expression of pro-inflammatory factors tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and IL-18 via downregulation of the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway. PI3K inhibition enhanced the ability of miR-125a to increase the inflammatory response in vitro via regulation of the PI3K/Akt/mTOR signaling pathway. These results suggest miR-125a inhibited autophagy in a model of thyroiditis through the PI3K/Akt/mTOR signaling pathway.

DINP aggravates autoimmune thyroid disease through activation of the Akt/mTOR pathway and suppression of autophagy in Wistar rats

Di-isononyl phthalate (DINP) is used as a substitute for traditional phthalates, in a wide range of applications. However, there is growing concern regarding its toxicity. Studies have indicated that DINP is related to thyroid hormone disorder and that phthalates can affect thyroid normal function. In this study, we aim to determine any effects of DINP exposure on autoimmune thyroid disease (AITD), the most common autoimmune disease, and to understand the underlying causal mechanism. AITD model Wistar rats were exposed to 0.15 mg/kg, 1.5 mg/kg or 15 mg/kg DINP. We assessed the thyroid globulin antibody levels, Th1/Th2 balance, histopathological changes and caspase-3 levels in the thyroid. The data show that exposure to DINP does indeed aggravate AITD. To explore the underlying mechanisms, we examined the levels of microtubule-associated protein 1 light chain 3 B (LC3B), Sequestosome 1 (SQSTM1) and the appearance of autophagosomes or autolysosomes to assess autophagy in the thyroid. The results show that DINP can suppress normal autophagy. We found that DINP induced an exacerbation of oxidative stress and the activation of the Akt/mTOR pathway, indicating that oxidative stress and activation of mTOR may play a key role in these processes. Moreover, the activation of mTOR also promoted the expression of IL-17. Importantly, blocking oxidative stress with VE or blocking Akt/mTOR with rapamycin mitigated the exacerbation of AITD and the suppression of normal autophagy. All these results indicate that exposure to DINP, especially high doses of DINP, can aggravate oxidative stress and activate the Akt/mTOR pathway. This exposure then leads to a suppression of normal autophagy and expression of IL-17 in the thyroid, resulting in an eventual exacerbation of AITD.

Excessive Iodine Promotes Pyroptosis of Thyroid Follicular Epithelial Cells in Hashimoto's Thyroiditis Through the ROS-NF-κB-NLRP3 Pathway

Hashimoto's thyroiditis (HT) is a common autoimmune thyroid disease. In recent years, increasing evidence has proven that the incidence of HT is associated with the excessive iodine intake of the body. In the present study, we measured the status of pyroptosis in thyroid tissues from patients with HT and the effects of excessive iodine on the pyroptosis in thyroid follicular cells (TFCs), in an attempt to illuminate the effects of iodine excess on the development of HT disease. Our results showed that increased pyroptosis occurred in the thyroid tissues of HT patients and that an increase in pyroptosis activity in TFCs was primed by excessive iodine in vitro. This process was mediated by reactive oxygen species (ROS) and activation of the NF-κB signaling pathway. In addition, excessive iodine caused NLRP3 inflammasome activation in TFCs, which promoted TFC pyroptosis. Moreover, the release of interleukin-1β (IL-1β) was closely linked to pyroptosis activation. Taken together, our results suggested that excessive iodine contributed to aberrant activation of pyroptosis in TFCs, which could be a pivotal predisposing factor for HT development.

Perigestational exposure to low doses of PBDE-47 induces excessive ER stress, defective autophagy and the resultant apoptosis contributing to maternal thyroid toxicity

Brominated flame retardant 2,2',4,4'‑tetrabromodiphenyl ether (PBDE-47) is known to induce developmental neurotoxicity by disturbing thyroid hormones (THs). Evidence shows that maternal THs are crucial for brain development and growth of fetuses and infants. However, little is known about the effects of PBDE-47 on maternal thyroid status and its mode of action. Here, using female Sprague-Dawley rats orally exposed to low doses of PBDE-47 (0.1, 1.0, 10 mg/kg/day) from pre-pregnancy until weaning of offspring to mimic human exposure, we show that perigestational exposure to PBDE-47 elevated serum triiodothyronine and thyroxine levels in mother rats. This is accompanied by disrupted thyroid follicle structure including expanded follicles, hyperplastic epithelial cells and shed cell remnants filled in the exhausted follicular lumen. Mechanistically, PBDE-47 enhanced apoptosis in thyroid tissue, as demonstrated by Caspase-3 activation, PARP cleavage and DNA fragmentation. Further study identified that PBDE-47 upregulated the levels of GRP78, ATF4, active Caspase-12 and CHOP, suggesting endoplasmic reticulum (ER) stress and unfolded protein response activation. Moreover, PBDE-47 reduced the levels of LC3-II, an autophagy marker protein essential for the autophagosomes formation, while increased the autophagy substrate p62 accumulation, indicating autophagy defect. Importantly, the colocalization of apoptotic cells with CHOP, a key mediator of ER stress-induced apoptosis, or p62, uncovered the contribution of excessive ER stress and defective autophagy to apoptosis. Collectively, our results suggest that excessive ER stress, defective autophagy and the resultant apoptosis are implicated in maternal thyroid injury following perigestational PBDE-47 exposure, which offers insight into a better understanding of PBDE-47-induced maternal thyroid toxicity.

Caveolin-1 regulates autophagy activity in thyroid follicular cells and is involved in Hashimoto's thyroiditis disease

Hashimoto's thyroiditis (HT) is considered a T helper-type 1 (Th1) cytokine-dominant autoimmune thyroid disease. Caveolin-1 (Cav-1), a part of the thyroxisome multiprotein complex, is localized at the apical pole of thyrocytes and is indispensable for synthesis of thyroid hormones and modulation of oxidative stress in order to avoid cell damage and apoptosis. Reduced autophagy induces thyroid follicular cells (TFC) apoptosis by activating reactive oxygen species (ROS) in HT patients. Nevertheless, whether Cav-1 has roles in the regulation of autophagy remains largely unclear. In this study, we examined Th1 cytokines and Cav-1 expression in HT thyroid tissues, determined the effects of interleukin-1beta (IL-1β) and interferon-gamma (IFN-γ) on Cav-1 and autophagy activity in TFC, and investigated the association between Cav-1 and autophagy activity in vitro. Our results indicate that higher levels of IL-1β and IFN-γ and lower levels of Cav-1 were expressed in thyroid tissues of HT patients than in those of normal controls. Cav-1 mRNA and protein levels were significantly decreased in TFC exposed to IL-1β and IFN-γ, accompanied by decreased expression of autophagy-related protein LC3B-II. Interestingly, small interfering RNA (siRNA)-mediated Cav-1 knockdown in TFC reduced LC3B-II protein expression. Taken together, these results suggest that lack of Cav-1 expression inhibited autophagy activity in TFC exposed to Th1 cytokines (IL-1β and IFN-γ), which might be a novel pathogenetic mechanism of HT.

Nitric oxide is involved in the hypothyroidism with significant morphology changes in female Wistar rats induced by chronic exposure to high water iodine from potassium iodate

Epidemiological studies indicated that chronic exposure to high water iodine is associated with primary hypothyroidism (PH) and subclinical hypothyroidism (SCH). However, the mechanism is not well understood. In this study, we explored whether chronic exposure to high water iodine from potassium iodate (KIO₃) can induce hypothyroidism in addition to determining if nitric oxide (NO) is involved in the pathogenesis. 96 female Wistar rats were divided into six groups: control, I_1000μg/L, I_3000μg/L, I_6000μg/L, N-nitro-L-arginine methylester (L-NAME) and L-NAME+I_6000μg/L. After 3 months, urine iodine concentration, thyroid hormone, NO and nitric oxide synthase (NOS) serum levels were determined. Additionally, thyroid expression of inducible nitric oxide synthase (iNOS) was also investigated. Thyroid morphology was observed under light microscopy and transmission electron microscope. SCH as indicated by elevated serum thyrotropin (TSH) was induced among rats exposed to 3000 μg/L I^-, while rats treated with 6000 μg/L I^- presented PH characterized by elevated TSH and lowered total thyroxine in serum. Moreover, serum NO, NOS and iNOS expression in the thyroid were significantly increased in I_3000μg/L and I_6000μg/L groups. Changes in thyroid function and morphology in the L-NAME+I_6000μg/L group were extenuated compared to I_6000μg/L group. These findings suggested that chronic exposure to high water iodine from KIO₃ likely induces hypothyroidism with significant morphology changes in female Wistar rats and NO appears to be involved in the pathogenesis.

Oxidative stress-mediated autophagic cell death participates in the neurotoxic effect on SH-SY5Y cells induced by excessive iodide

Excessive iodide could induce intellectual damage in children, which has attracted broad attention. To investigate the neurotoxic effect of iodide and its mechanism, a human dopaminergic neuroblastoma cell line (SH-SY5Y) was treated with different concentrations of potassium iodide (KI). The results showed that excessive iodide could decrease cell viability, reduce glutathione (GSH) and superoxide dismutase (SOD), and increase the degree of autophagy (by changing the cellular ultrastructure and raising the autophagy-related mRNA and protein expression of LC3, Beclin1, and p62), which were correlated with the immunofluorescence labeling. Furthermore, treatment with the autophagy inhibitor 3-methyladenine (3MA), antioxidant N-acetylcysteine (NAC) and 30 mM KI for 24 h was conducted in the following research. 3MA significantly decreased autophagy-related mRNA and protein expression and improved cell viability, indicating that excess iodide induced autophagic cell death. In addition, oxidative stress regulated autophagy, reflected by the results that NAC decreased the mRNA and protein expression of LC3, Beclin1, and p62. In summary, autophagic cell death mediated by oxidative stress may participate in excessive iodide-induced SH-SY5Y cell death.

Aberrant MRP14 expression in thyroid follicular cells mediates chemokine secretion through the IL-1β/MAPK pathway in Hashimoto's thyroiditis

Myeloid-related protein 14 (MRP14) is responsible for inflammatory reactions. However, the correlation between MRP14 and Hashimoto's thyroiditis (HT) is still not clear. In this study, we examined the status of MRP14 in thyroid tissues and sera of HT patients and explored the mechanism of IL-1β-mediated regulation of MRP14 expression, as well as the effects of MRP14 on pro-inflammatory chemokine secretion in thyroid follicular cells (TFCs), to elucidate the role of MRP14 in HT development. Our results showed dramatically increased MRP14 expression in thyroid tissues and sera from HT patients. In addition, IL-1β significantly promoted the expression of MRP14 in TFCs, which was mediated by activation of the MAPK/NF-κB signalling pathway. More importantly, IL-1β induced the secretion of the chemokines GRO-2, CXCL9 and CCL22, which was dependent on the regulation of MRP14 in TFCs. Therefore, these findings suggested that under pro-inflammatory conditions, TFCs secreted chemokines with the help of MRP14 regulation, which might suggest a potential pathological mechanism of lymphocyte infiltration into the thyroid gland in HT.

Autoimmunity in 2016

The number of peer-reviewed articles published during the 2016 solar year and retrieved using the "autoimmunity" key word remained stable while gaining a minimal edge among the immunology articles. Nonetheless, the quality of the publications has been rising significantly and, importantly, acquisitions have become available through scientific journals dedicated to immunology or autoimmunity. Major discoveries have been made in the fields of systemic lupus erythematosus, rheumatoid arthritis, autoimmunity of the central nervous system, vasculitis, and seronegative spondyloarthrithritides. Selected examples include the role of IL17-related genes and long noncoding RNAs in systemic lupus erythematosus or the effects of anti-pentraxin 3 (PTX3) in the treatment of this paradigmatic autoimmune condition. In the case of rheumatoid arthritis, there have been reports of the role of induced regulatory T cells (iTregs) or fibrocytes and T cell interactions with exciting implications. The large number of studies dealing with neuroimmunology pointed to Th17 cells, CD56(bright) NK cells, and low-level TLR2 ligands as involved in multiple sclerosis, along with a high salt intake or the micriobiome-derived Lipid 654. Lastly, we focused on the rare vasculitides to which numerous studies were devoted and suggested that unsuspected cell populations, including monocytes, mucosal-associated invariant T cells, and innate lymphoid cells, may be crucial to ANCA-associated manifestations. This brief and arbitrary discussion of the findings published in 2016 is representative of a promising background for developments that will enormously impact the work of laboratory scientists and physicians at an exponential rate.

Sparstolonin B attenuates spinal cord injury‑induced inflammation in rats by modulating TLR4‑trafficking

The present study used a spinal cord injury (SCI) model to evaluate whether sparstolonin B was able to prevent SCI, and to investigate the underlying signaling mechanism. Sparstolonin B attenuated the SCI‑induced Batto, Beattie and Bresnahan score and water content in rats. Sparstolonin B attenuated the mRNA expression of proinflammatory cytokines interleukin (IL)‑18, IL‑6, IL‑1β, and IL‑23, decreased the levels of tumor necrosis factor‑α and interferon‑γ, and decreased caspase‑3 activity and apoptosis regulator Bax protein expression in SCI rats. Similarly, sparstolonin B inhibited monocyte chemoattractant protein‑1 mRNA levels, and Toll‑like receptor (TLR) 4, myeloid differentiation primary response protein MyD88 (MyD88) and nuclear factor (NF)‑κB protein levels in SCI rats. The present results suggested that sparstolonin B may attenuate SCI‑induced inflammation and apoptosis in rats by modulating the TLR4/MyD88/NF‑κB signaling pathway.

IL-34 Expression Is Reduced in Hashimoto's Thyroiditis and Associated With Thyrocyte Apoptosis

Hashimoto's thyroiditis (HT) is a common autoimmune disease accompanied by lymphocyte infiltration and thyroid tissue destruction. IL-34 was first described in 2008, and its involvement in the development of many autoimmune diseases has been recently identified. However, whether IL-34 is a regulatory factor in HT is unclear. Here, we demonstrate that IL-34 is expressed on thyroid follicular epithelial cells and that IL-34 expression is significantly reduced in thyroid tissue in patients with HT and spontaneous autoimmune thyroiditis (SAT) models. Serum IL-34 levels in patients with HT are also significantly reduced. In addition, IL-34 is associated with thyroid autoantibodies in both thyroid tissue and serum. Furthermore, our data show that IL-34 participates in the apoptosis resistance of thyrocytes in HT induced by CSF-1R and may be a potential indicator for evaluating thyrocyte damage.

Iodinated TG in Thyroid Follicles Regulate TSH/TSHR Signaling for NIS Expression

Our previous research has suggested that high degree of iodinated thyroglobulin (TG) may inhibit the expression and function of sodium iodide symporter (NIS), but the underlying mechanism remains unclear. In present study, we discuss a newly constructed follicle model in vitro, which was used to simulate the follicular structure of the thyroid and explore the regulatory roles of iodinated TG in the follicular lumen on NIS expression. The results showed that both NIS expression and PKA activity were increased in lowly iodinated TG group, while decreased NIS expression with increased PKC activity was found in highly iodinated TG group. Also, NIS expression was increased in PKA agonist-treated group, while decreased NIS was found in PKC agonist-treated group. Moreover, when the PLC-PKC pathway was blocked by PKC-specific inhibitor, highly iodinated TG significantly promoted the expression of NIS. However, when the cAMP-PKA pathway was blocked by a PKA-specific blocker, highly iodinated TG slightly suppressed NIS expression. TG with a low degree of iodination had the reverse effect on NIS. When the PLC-PKC pathway was blocked, TG with a low degree of iodination slightly promoted NIS expression. However, when the cAMP-PKA pathway was blocked, TG with a low degree of iodination greatly inhibited NIS expression. All these suggested that iodinated TG inhibited the expression of NIS by PLC-PKC pathway and promoted NIS expression via the cAMP-PKA pathway. When highly iodinated TG was present, the PLC-PKC pathway became dominant. In the presence of lowly iodinated TG, the cAMP-PKA became the major pathway.