Search

Abstract Background Inflammatory diseases are often initiated by the activation of inflammasomes triggered by pathogen-associated molecular patterns (PAMPs) and endogenous damage-associated molecular patterns (DAMPs), which mediate pyroptosis. Although pyroptosis resulting from aberrant inflammasome triggering in thyroid follicular cells (TFCs) has been observed in Hashimoto's thyroiditis (HT) patients, the underlying mechanisms remain largely unknown. Given the extensive involvement of protein ubiquitination and deubiquitination in inflammatory diseases, we aimed to investigate how deubiquitinating enzymes regulate thyroid follicular cell pyroptosis and HT pathogenesis. Methods Our study specifically investigated the role of Ubiquitin-specific peptidase 1 (USP1), a deubiquitinase (DUB), in regulating the inflammasome components NLRP3 and AIM2, which are crucial in pyroptosis. We conducted a series of experiments to elucidate the function of USP1 in promoting pyroptosis associated with inflammasomes and the progression of HT. These experiments involved techniques such as USP1 knockdown or inhibition, measurement of key pyroptosis indicators including caspase-1, caspase-1 p20, and GSDMD-N, and examination of the effects of USP1 abrogation on HT using a mouse model. Furthermore, we explored the impact of USP1 on NLRP3 transcription and its potential interaction with p65 nuclear transportation. Results Our findings provide compelling evidence indicating that USP1 plays a pivotal role in promoting inflammasome-mediated pyroptosis and HT progression by stabilizing NLRP3 and AIM2 through deubiquitination. Furthermore, we discovered that USP1 modulates the transcription of NLRP3 by facilitating p65 nuclear transportation. Knockdown or inhibition of USP1 resulted in weakened cell pyroptosis, as evidenced by reduced levels of caspase-1 p20 and GSDMD-N, which could be restored upon AIM2 overexpression. Remarkably, USP1 abrogation significantly ameliorated HT in the mice model, likely to that treating mice with pyroptosis inhibitors VX-765 and disulfiram. Conclusions Our study highlights a regulatory mechanism of USP1 on inflammasome activation and pyroptosis in TFCs during HT pathogenesis. These findings expand our understanding of HT and suggest that inhibiting USP1 may be a potential treatment strategy for managing HT.

Background: Inflammatory diseases are often initiated by the activation of inflammasomes triggered by pathogen-associated molecular patterns (PAMPs) and endogenous damage-associated molecular patterns (DAMPs), which mediate pyroptosis. Although pyroptosis resulting from aberrant inflammasome triggering in thyroid follicular cells (TFCs) has been observed in Hashimoto's thyroiditis (HT) patients, the underlying mechanisms remain largely unknown. Given the extensive involvement of protein ubiquitination and deubiquitination in inflammatory diseases, we aimed to investigate how deubiquitinating enzymes regulate thyroid follicular cell pyroptosis and HT pathogenesis. Methods: Our study specifically investigated the role of Ubiquitin-specific peptidase 1 (USP1), a deubiquitinase (DUB), in regulating the inflammasome components NLRP3 and AIM2, which are crucial in pyroptosis. We conducted a series of experiments to elucidate the function of USP1 in promoting pyroptosis associated with inflammasomes and the progression of HT. These experiments involved techniques such as USP1 knockdown or inhibition, measurement of key pyroptosis indicators including caspase-1, caspase-1 p20, and GSDMD-N, and examination of the effects of USP1 abrogation on HT using a mouse model. Furthermore, we explored the impact of USP1 on NLRP3 transcription and its potential interaction with p65 nuclear transportation. Results: Our findings provide compelling evidence indicating that USP1 plays a pivotal role in promoting inflammasome-mediated pyroptosis and HT progression by stabilizing NLRP3 and AIM2 through deubiquitination. Furthermore, we discovered that USP1 modulates the transcription of NLRP3 by facilitating p65 nuclear transportation. Knockdown or inhibition of USP1 resulted in weakened cell pyroptosis, as evidenced by reduced levels of caspase-1 p20 and GSDMD-N, which could be restored upon AIM2 overexpression. Remarkably, USP1 abrogation significantly ameliorated HT in the mice model, likely to that treating mice with pyroptosis inhibitors VX-765 and disulfiram. Conclusions: Our study highlights a regulatory mechanism of USP1 on inflammasome activation and pyroptosis in TFCs during HT pathogenesis. These findings expand our understanding of HT and suggest that inhibiting USP1 may be a potential treatment strategy for managing HT. [ABSTRACT FROM AUTHOR]

Abstract Background Loss of the transcription factor GLI-Similar 3 (GLIS3) function causes congenital hypothyroidism (CH) in both humans and mice due to decreased expression of several thyroid hormone (TH) biosynthetic genes in thyroid follicular cells. Whether and to what extent, GLIS3 regulates thyroid gene transcription in coordination with other thyroid transcriptional factors (TFs), such as PAX8, NKX2.1 and FOXE1, is poorly understood. Methods PAX8, NKX2.1, and FOXE1 ChIP-Seq analysis with mouse thyroid glands and rat thyrocyte PCCl3 cells was performed and compared to that of GLIS3 to analyze the co-regulation of gene transcription in thyroid follicular cells by these TFs. Results Analysis of the PAX8, NKX2.1, and FOXE1 cistromes identified extensive overlaps between these TF binding loci and those of GLIS3 indicating that GLIS3 shares many of the same regulatory regions with PAX8, NKX2.1, and FOXE1, particularly in genes associated with TH biosynthesis, induced by thyroid stimulating hormone (TSH), and suppressed in Glis3KO thyroid glands, including Slc5a5 (Nis), Slc26a4, Cdh16, and Adm2. ChIP-QPCR analysis showed that loss of GLIS3 did not significantly affect PAX8 or NKX2.1 binding and did not cause major alterations in H3K4me3 and H3K27me3 epigenetic signals. Conclusions Our study indicates that GLIS3 regulates transcription of TH biosynthetic and TSH-inducible genes in thyroid follicular cells in coordination with PAX8, NKX2.1, and FOXE1 by binding within the same regulatory hub. GLIS3 does not cause major changes in chromatin structure at these common regulatory regions. GLIS3 may induce transcriptional activation by enhancing the interaction of these regulatory regions with other enhancers and/or RNA Polymerase II (Pol II) complexes.

Background: Loss of the transcription factor GLI-Similar 3 (GLIS3) function causes congenital hypothyroidism (CH) in both humans and mice due to decreased expression of several thyroid hormone (TH) biosynthetic genes in thyroid follicular cells. Whether and to what extent, GLIS3 regulates thyroid gene transcription in coordination with other thyroid transcriptional factors (TFs), such as PAX8, NKX2.1 and FOXE1, is poorly understood. Methods: PAX8, NKX2.1, and FOXE1 ChIP-Seq analysis with mouse thyroid glands and rat thyrocyte PCCl3 cells was performed and compared to that of GLIS3 to analyze the co-regulation of gene transcription in thyroid follicular cells by these TFs. Results: Analysis of the PAX8, NKX2.1, and FOXE1 cistromes identified extensive overlaps between these TF binding loci and those of GLIS3 indicating that GLIS3 shares many of the same regulatory regions with PAX8, NKX2.1, and FOXE1, particularly in genes associated with TH biosynthesis, induced by thyroid stimulating hormone (TSH), and suppressed in Glis3KO thyroid glands, including Slc5a5 (Nis), Slc26a4, Cdh16, and Adm2. ChIP-QPCR analysis showed that loss of GLIS3 did not significantly affect PAX8 or NKX2.1 binding and did not cause major alterations in H3K4me3 and H3K27me3 epigenetic signals. Conclusions: Our study indicates that GLIS3 regulates transcription of TH biosynthetic and TSH-inducible genes in thyroid follicular cells in coordination with PAX8, NKX2.1, and FOXE1 by binding within the same regulatory hub. GLIS3 does not cause major changes in chromatin structure at these common regulatory regions. GLIS3 may induce transcriptional activation by enhancing the interaction of these regulatory regions with other enhancers and/or RNA Polymerase II (Pol II) complexes. [ABSTRACT FROM AUTHOR]

ObjectiveThe differentiation program for human thyroid follicular cells (TFCs) relies on the interplay between sequence-specific transcription factors and transcriptional co-regulators. Transcriptional co-activator with PDZ-binding motif (TAZ) is a co-activator that regulates several transcription factors, including PAX8 and NKX2-1, which play a central role in thyroid-specific gene transcription. TAZ and PAX8/NKX2-1 are co-expressed in the nuclei of thyroid cells, and TAZ interacts directly with both PAX8 and NKX2-1, leading to their enhanced transcriptional activity on the thyroglobulin (TG) promoter and additional genes.MethodsThe use of a small molecule, ethacridine, recently identified as a TAZ activator, in the differentiation of thyroid cells from human embryonic stem (hES) cells was studied. First, endodermal cells were derived from hES cells using Activin A, followed by induction of differentiation into thyroid cells directed by ethacridine and thyrotropin (TSH).ResultsThe expression of TAZ was increased in the Activin A-derived endodermal cells by ethacridine in a dose-dependent manner and followed by increases in PAX8 and NKX2-1 when assessed by both quantitative polymerase chain reaction and immunostaining. Following further differentiation with the combination of ethacridine and TSH, the thyroid-specific genes TG, TPO, TSHR, and NIS were all induced in the differentiated hES cells. When these cells were cultured with extracellular matrix-coated dishes, thyroid follicle formation and abundant TG protein expression were observed. Furthermore, such hES cell-derived thyroid follicles showed a marked TSH-induced and dose-dependent increase in radioiodine uptake and protein-bound iodine accumulation.ConclusionThese data show that fully functional human thyroid cells can be derived from hES cells using ethacridine, a TAZ activator, which induces thyroid-specific gene expression and promotes thyroid cell differentiation from the hES cells. These studies again demonstrate the importance of transcriptional regulation in thyroid cell development. This approach also yields functional human thyrocytes, without any gene transfection or complex culture conditions, by directly manipulating the transcriptional machinery without interfering with intermediate signaling events.

The transcription factor CREB3L1 is expressed in a wide variety of tissues including cartilage, pancreas, and bone. It is located in the endoplasmic reticulum and upon stimulation is transported to the Golgi where is proteolytically cleaved. Then, the N-terminal domain translocates to the nucleus to activate gene expression. In thyroid follicular cells, CREB3L1 is a downstream effector of thyrotropin (TSH), promoting the expression of proteins of the secretory pathway along with an expansion of the Golgi volume. Here, we analyzed the role of CREB3L1 as a TSH-dependent transcriptional regulator of the expression of the sodium/iodide symporter (NIS), a major thyroid protein that mediates iodide uptake. We show that overexpression and inhibition of CREB3L1 induce an increase and decrease in the NIS protein and mRNA levels, respectively. This, in turn, impacts on NIS-mediated iodide uptake. Furthermore, CREB3L1 knockdown hampers the increase the TSH-induced NIS expression levels. Finally, the ability of CREB3L1 to regulate the promoter activity of the NIS-coding gene (Slc5a5) was confirmed. Taken together, our findings highlight the role of CREB3L1 in maintaining the homeostasis of thyroid follicular cells, regulating the adaptation of the secretory pathway as well as the synthesis of thyroid-specific proteins in response to TSH stimulation. [ABSTRACT FROM AUTHOR]

Stem cell-based therapies to reconstitute in vivo organ function hold great promise for future clinical applications to a variety of diseases. Hypothyroidism resulting from congenital lack of functional thyrocytes, surgical tissue removal, or gland ablation, represents a particularly attractive endocrine disease target that may be conceivably cured by transplantation of long-lived functional thyroid progenitors or mature follicular epithelial cells, provided a source of autologous cells can be generated and a variety of technical and biological challenges can be surmounted. Here we review the emerging literature indicating that thyroid follicular epithelial cells can now be engineered in vitro from the pluripotent stem cells (PSCs) of mice, normal humans, or patients with congenital hypothyroidism. We review the in vivo embryonic development of the thyroid gland and explain how emerging discoveries in developmental biology have been utilized as a roadmap for driving PSCs, which resemble cells of the early embryo, into mature functional thyroid follicles in vitro. Finally, we discuss the bioengineering, biological, and clinical hurdles that now need to be addressed if the goals of life-long cure of hypothyroidism through cell- and/or gene-based therapies are to be attained.

Stem cell-based therapies to reconstitute in vivo organ function hold great promise for future clinical applications to a variety of diseases. Hypothyroidism resulting from congenital lack of functional thyrocytes, surgical tissue removal, or gland ablation, represents a particularly attractive endocrine disease target that may be conceivably cured by transplantation of long-lived functional thyroid progenitors or mature follicular epithelial cells, provided a source of autologous cells can be generated and a variety of technical and biological challenges can be surmounted. Here we review the emerging literature indicating that thyroid follicular epithelial cells can now be engineered in vitro from the pluripotent stem cells (PSCs) of mice, normal humans, or patients with congenital hypothyroidism. We review the in vivo embryonic development of the thyroid gland and explain how emerging discoveries in developmental biology have been utilized as a roadmap for driving PSCs, which resemble cells of the early embryo, into mature functional thyroid follicles in vitro. Finally, we discuss the bioengineering, biological, and clinical hurdles that now need to be addressed if the goals of life-long cure of hypothyroidism through cell- and/or gene-based therapies are to be attained. [ABSTRACT FROM AUTHOR]

The transcription factor CREB3L1 is expressed in a wide variety of tissues including cartilage, pancreas, and bone. It is located in the endoplasmic reticulum and upon stimulation is transported to the Golgi where is proteolytically cleaved. Then, the N-terminal domain translocates to the nucleus to activate gene expression. In thyroid follicular cells, CREB3L1 is a downstream effector of thyrotropin (TSH), promoting the expression of proteins of the secretory pathway along with an expansion of the Golgi volume. Here, we analyzed the role of CREB3L1 as a TSH-dependent transcriptional regulator of the expression of the sodium/iodide symporter (NIS), a major thyroid protein that mediates iodide uptake. We show that overexpression and inhibition of CREB3L1 induce an increase and decrease in the NIS protein and mRNA levels, respectively. This, in turn, impacts on NIS-mediated iodide uptake. Furthermore, CREB3L1 knockdown hampers the increase the TSH-induced NIS expression levels. Finally, the ability of CREB3L1 to regulate the promoter activity of the NIS-coding gene (Slc5a5) was confirmed. Taken together, our findings highlight the role of CREB3L1 in maintaining the homeostasis of thyroid follicular cells, regulating the adaptation of the secretory pathway as well as the synthesis of thyroid-specific proteins in response to TSH stimulation.

Introduction: Thyroid disorders are very common all over India, more so in Kerala. Although definite histologic criteria exist for diagnosing various thyroid lesions, there is an overlap of many nuclear and cytoplasmic features like nuclear atypia, enlargement etc., between both non-neoplastic and neoplastic lesions. This sometimes leads to a diagnostic dilemma in differentiating these lesions. CD56 is expressed by many tissues in the body including normal thyroid follicular epithelium, this expressivity being absent or reduced in Papillary Thyroid Carcinoma (PTC). Normal thyroid follicular cells do not express p63. Aberrant expression of p63 on thyroid epithelium is thus a marker of proliferation and tumourigenesis. Aim: To assess the expression of CD56 and p63 in various nonneoplastic and neoplastic thyroid lesions and to calculate the percentage of positivity and negativity in these lesions. Materials and Methods: This was a prospective study of 100 thyroidectomy specimens submitted to the Department of Pathology, Govt. TD Medical College, Alappuzha from January 2016 to June 2017. H&E stained sections of these specimens were studied and Immunohistochemical (IHC) staining with CD56 and p63 markers was performed on all and their expressions, positive or negative, were evaluated and expressed as percentage values. Results: Out of 100 thyroidectomy specimens studied, total number of non-neoplastic cases was 58 and neoplastic lesions (benign and malignant) were 42. The most common nonneoplastic lesion was lymphocytic thyroiditis (39/58). Most common malignant thyroid neoplasm was PTC (35/42). CD56 showed membranous positivity in 53/58 (91.4%) non-neoplastic lesions and only 4/42 (9.5%) neoplastic lesions. Nuclear positivity for p63 was seen in only a small proportion (18/100, i.e., 18%) of all lesions. Conclusion: Significance of this study lies in the fact that CD56 is expressed in most non-neoplastic lesions of thyroid and is found negative in thyroid malignancies. The p63 even though considered to be a proliferation marker is negative in most of nonneoplastic as well as neoplastic lesions in the present study.

We aimed to investigate the role of programmed cell death protein 1 (PD-1) and T lymphocytes in the proliferation, apoptosis and secretion of cells from patients and mice with Graves' disease (GD). The levels of serum hormones, related antibodies and inflammatory cytokines in GD patients were determined by electrochemiluminescence immunoassay and ELISA. The percentages of CD4 and CD8 T-lymphocytes and PD-1 expression were examined by flow cytometry. A GD mouse model, a thyroid follicular epithelial cell, and a CD4+PD-1+, CD4+PD-1- and CD8+PD-1+, CD8+PD-1- T lymphocyte co-culture system were constructed. The viability, apoptosis-related markers, serum hormones, related antibodies and inflammatory cytokines in thyroid follicular epithelial cells were determined by CCK-8, Western blot, qTR-PCR, electrochemiluminescence immunoassay and ELISA. Elevated free thyroid hormones (FT3, FT4), thyroid hormone antibodies (TRAb, TPOAb and TGAb), inflammatory cytokines, and inhibited TSH were observed in GD patients. The percentage of CD4+ T cells was increased, while that of CD8+ T cells was reduced in GD patients. PD-1 expression level was lifted in both CD4+ and CD8+ cells from GD patients. In mouse thyroid follicular epithelial cells co-cultured with CD4+PD-1+ and CD8+PD-1+ T lymphocytes, the cell viability, TH and TRAb levels and inflammatory cytokines level were the highest, while the TSH level and apoptosis were the lowest. PD-1 positive T lymphocytes were able to promote viability and inhibit apoptosis of thyroid follicular epithelial cells, which further caused a more accelerated development of GD. [ABSTRACT FROM AUTHOR]

Introduction: Thyroid disorders are very common all over India, more so in Kerala. Although definite histologic criteria exist for diagnosing various thyroid lesions, there is an overlap of many nuclear and cytoplasmic features like nuclear atypia, enlargement etc., between both non-neoplastic and neoplastic lesions. This sometimes leads to a diagnostic dilemma in differentiating these lesions. CD56 is expressed by many tissues in the body including normal thyroid follicular epithelium, this expressivity being absent or reduced in Papillary Thyroid Carcinoma (PTC). Normal thyroid follicular cells do not express p63. Aberrant expression of p63 on thyroid epithelium is thus a marker of proliferation and tumourigenesis. Aim: To assess the expression of CD56 and p63 in various nonneoplastic and neoplastic thyroid lesions and to calculate the percentage of positivity and negativity in these lesions. Materials and Methods: This was a prospective study of 100 thyroidectomy specimens submitted to the Department of Pathology, Govt. TD Medical College, Alappuzha from January 2016 to June 2017. H&E stained sections of these specimens were studied and Immunohistochemical (IHC) staining with CD56 and p63 markers was performed on all and their expressions, positive or negative, were evaluated and expressed as percentage values. Results: Out of 100 thyroidectomy specimens studied, total number of non-neoplastic cases was 58 and neoplastic lesions (benign and malignant) were 42. The most common nonneoplastic lesion was lymphocytic thyroiditis (39/58). Most common malignant thyroid neoplasm was PTC (35/42). CD56 showed membranous positivity in 53/58 (91.4%) non-neoplastic lesions and only 4/42 (9.5%) neoplastic lesions. Nuclear positivity for p63 was seen in only a small proportion (18/100, i.e., 18%) of all lesions. Conclusion: Significance of this study lies in the fact that CD56 is expressed in most non-neoplastic lesions of thyroid and is found negative in thyroid malignancies. The p63 even though considered to be a proliferation marker is negative in most of nonneoplastic as well as neoplastic lesions in the present study. [ABSTRACT FROM AUTHOR]

Lithium (Li) is used for the treatment and prophylaxis of mental disorders, associated with many serious hazards. Resveratrol (RSV) has various beneficial therapeutic effects. Platelet-rich plasma (PRP) is a new promising curative tool. This study aimed to assess the impacts of RSV versus PRP on lithium-induced thyroid follicular cell toxicity in adult male rats. Forty-nine adult male rats were divided into four groups: group I: control rats; group II: lithium-treated rats; group III: lithium- and resveratrol-treated rats; group IV: lithium and PRP-treated rats. Thyroid specimens were taken and processed for histological and immunohistochemical methods. Morphometrical studies and statistical analysis were done. Group II showed distorted thyroid follicles, significantly increased collagen fibers, and highly positive P53 immunostaining (P < 0.01). Ultrastructural examination showed dilated rough endoplasmic reticulum and damaged mitochondria. Groups III and IV exhibited significant amelioration of the histological and electron microscopic changes mentioned previously. PRP remedy was more effective than RSV for treatment of Li-induced thyroid follicular cell toxicity. [ABSTRACT FROM AUTHOR]

The replacement of regenerated thyroid follicular cells (TFCs) is a promising therapeutic strategy for patients with hypothyroidism. Here, we have succeeded in inducing functional TFCs from human-induced pluripotent stem cells (iPSCs) in scalable suspension culture. Differentiation of iPSCs with Activin A treatment produced Sox17- and FoxA2-expressing definitive endodermal cells that also expressed thyroid transcription factors Pax8 and Nkx2-1. Further treatment with thyroid-stimulating hormone (TSH) induced TFCs expressing various types of thyroid proteins including TSH receptor, sodium–iodide symporter, thyroglobulin, and thyroid peroxidase. Interestingly, differentiated cells secreted free thyroxine in vitro. These results indicate successful differentiation of human iPSCs to functional TFCs that may enable us to fabricate thyroid tissues for regenerative medicine and disease models.

In contrast to studies in women, male osteoporosis is poorly understood and strictly related to advancing age. Among the first antiresorptive substances used in the prevention and treatment of osteoporosis is calcitonin ( CT), a hypocalcemic hormone that potently inhibits osteoclastic bone resorption. Natural CT is produced and secreted by thyroid C-cells. The other endocrine population of thyroid cells produces thyroid hormones ( TH), which also affect bone turnover. The aim of this study was to evaluate the influence of salmon CT on trabecular bone microarchitecture with special reference to effects on the structure and function of both CT- and TH-producing thyroid cells in orchidectomized (Orx) middle-aged rats. Twenty-four male Wistar rats aged 15 months were randomly divided into Orx and sham-operated ( SO) groups. One group of Orx animals received (s.c.) synthetic salmon CT (Orx + CT; 100 IU kg−1 b.w.) subcutaneously every second day for 6 weeks. The second Orx group and SO rats were given the same volume of vehicle alone by the same schedule. Trabecular bone histomorphometrical parameters were: cancellous bone area (B.Ar), trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular separation (Tb.Sp) were obtained with an ImageJ public-domain image-processing program. The peroxidase-antiperoxidase method was applied for localization of CT in C-cells. Anti-human CT antisera served as the primary antibodies. For immunohistochemical characterization of vascular endothelial growth factor ( VEGF) in thyroid tissue, rabbit antisera against human VEGF, served as primary antibodies. CT-immunopositive thyroid C-cells, thyroid follicular epithelium, interstitium and colloid were evaluated morphometrically. Blood serum samples were analyzed for CT, osteocalcin ( OC), and thyroxine (T4), and calcium (Ca2+) concentration was determined in urine samples. Salmon CT application significantly increased B.Ar, TbTh and TbN, but markedly decreased Tb.Sp. Administration of exogenous CT significantly decreased mean volume (Vc) and relative volume density (Vv) of thyroid C-cells in relation to both SO and Orx groups. The Vv of the colloid was higher, whereas the VV of the follicular epithelium was lower after CT treatment compared with Orx alone. CT treatment markedly elevated serum CT, whereas serum OC, T4 and urinary Ca2+ concentrations were lower than in the Orx group. These results indicate that salmon CT stimulates trabecular bone microarchitecture, strongly inhibits thyroid C-cells and changes the structure of the thyroid gland, indicating hypoactivity. [ABSTRACT FROM AUTHOR]

Background Extract from the leaves of the Ginkgo biloba tree are used as a herbal remedy and dietary supplement. Numerous studies have suggested its therapeutic activity against many health disorders. However, it was found to be associated with histological changes in some organs. Recently, increased awareness about its safety and the potential hazards associated with its use were spotlighted. Aim The goal of the study was to assess the impact of G. biloba extract (GBE) on the histological structure and function of thyroid follicular cells of adult male albino rats. Materials and methods Thirty rats were categorized into three equal groups: group I, group II, and group III. Animals of group I were given distilled water and served as controls. GBE was given (100 mg/kg) orally for 4 and 6 weeks to group II and group III rats, respectively. At the designated times of the study, blood samples were taken for determination of serum triiodothyronine, thyroxin, and thyroid stimulating hormone. Rats were then euthanized, and thyroid lobes were processed for both light and electron microscopic examinations. Results The groups of animals exposed to GBE experienced histological changes in the follicular cells. These lesions included hypertrophy and hyperplasia of follicular cells. Group II showed evidence of hypertrophy wherein the follicles were lined with tall columnar cells. Nevertheless, group III showed many follicles lined with more than one layer of cells, along with colloid depletion. Ultrastructurally, dilated rough endoplasmic reticulum and swollen disrupted mitochondria as well as nuclear changes were further encountered in both groups. These histological changes were accompanied by alteration in the measured hormonal levels. Conclusion The study concluded that GBE administration to albino rats, either for 4 or for 6 weeks, caused alteration of thyroid follicular cell structure and function. [ABSTRACT FROM AUTHOR]

Abstract: (C–X–C motif) ligand (CXCL)10 (CXCL10) belongs to the ELR− CXC subfamily chemokine. CXCL10 exerts its function through binding to chemokine (C–X–C motif) receptor 3 (CXCR3), a seven trans-membrane receptor coupled to G proteins. CXCL10 and its receptor, CXCR3, appear to contribute to the pathogenesis of many autoimmune diseases, organ specific (such as type 1 diabetes, autoimmune thyroiditis, Graves' disease and ophthalmopathy), or systemic (such as rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, mixed cryoglobulinemia, Sjögren syndrome, or systemic sclerosis). The secretion of CXCL10 by cluster of differentiation (CD)4+, CD8+, natural killer (NK) and NK-T cells is dependent on interferon (IFN)-γ, which is itself mediated by the interleukin-12 cytokine family. Under the influence of IFN-γ, CXCL10 is secreted by several cell types including endothelial cells, fibroblasts, keratinocytes, thyrocytes, preadipocytes, etc. Determination of high level of CXCL10 in peripheral fluids is therefore a marker of host immune response, especially T helper (Th)1 orientated T-cells. In tissues, recruited Th1 lymphocytes may be responsible for enhanced IFN-γ and tumor necrosis factor-α production, which in turn stimulates CXCL10 secretion from a variety of cells, therefore creating an amplification feedback loop, and perpetuating the autoimmune process. Further studies are needed to investigate interactions between chemokines and cytokines in the pathogenesis of autoimmune diseases and to evaluate whether CXCL10 is a novel therapeutic target in various autoimmune diseases. [Copyright &y& Elsevier]

Background: The role of costimulatory molecules expressed on lymphocytes and thyrocytes in hyperthyroidism has attracted increasing attention and research has shown a close correlation between variant expression of these molecules on lymphocytes and thyrocytes and the development of GD. Meterials and Methods: Thyroid tissues were collected from GD patients during surgery and from Hashimoto disease (HT) and non-toxic goiter (NTG) patients as controls. ICOSL expression on infiltrated B cells and TFC was detected by flow cytometry (FCM), reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC). Variation in ICOSL expression on TFC in primary cultures was analyzed in the absence or presence of cytokines using FCM assays. The role of ICOS-ICOSL signaling in proliferation, thyroid hormone production and thyroglobulin (Tg) release was investigated in primary TFC cultures using ICOS gene transfected L929 cells (ICOS-L929 cells) and the blocking ICOSL antibody (11 C4) in MTT assays and radioimmunoassays. Results and Discussion: ICOSL expression on infiltrated B cells and TFC was detected in GD patient tissue. However, ICOSL expression was only detected on infiltrated B cells in control HT and NTG patient tissue. ICOSL expression on TFC was induced in vitro by the proinflammatory cytokines IFN-γ, IL-6 and TNF-α. Compared with mock transfected L929 (mock-L929) control cells, ICOS-L929 cells promoted significant proliferation of primary cultured TFC, with increased thyroid hormone and Tg production (all P < 0.01). TFC proliferation and production of thyroid hormones and Tg were inhibited significantly in the presence of ICOSL blocking antibody (11 C4) (all P < 0.05). Our observations suggest that ICOS-ICOSL signal plays a direct role in proliferation and differentiation of TFC and may exert important effects in the initiation, maintenance and exaggeration of autoimmune responses in local tissue. [ABSTRACT FROM AUTHOR]

Terminal complement complexes have been identified around thyroid follicles in Graves' disease and Hashimoto's thyroiditis, and the concentrations of such complexes are increased in the sera of these patients, suggesting a role for complement activation and membrane attack complexes (MAC) in autoimmune thyroiditis. This has been investigated further using cultured human and rat thyroid cells. Thyrocytes were resistant to lysis by homologous complement, in contrast to the effects of heterologous (rabbit) complement. The formation of non-lethal amounts of MAC, using reactive lysis or classical pathway activation, significantly reduced cAMP production by these cells in response to thyroid-stimulating hormone (TSH) (P<0.01); similar effects were seen with thyroid stimulating antibodies. Thyroid cells were able to recover rapidly from complement attack after washing and incubation for 30 min. Non-lethal MAC formation also resulted in reactive oxygen metabolite production, detected by luminol-dependent chemiluminescence in three out of five thyroid cell preparations tested. Ionomycin, but not TSH, also stimulated reactive oxygen metabolite production. These results suggest that repeated or continuous sub-lethal complement attack on thyroid cells may exacerbate hypothyroidism in Hashimoto's thyroiditis, or partially counter the effects of thyroid-stimulating antibodies in Graves' disease. Furthermore, the production of reactive oxygen metabolites in these circumstances could increase the intra-thyroidal inflammatory response; oxygen radical scavenging by anti-thyroid drugs (which are concentrated by thyrocytes)may account in part for the amelioration of thyroiditis observed with such treatment. [ABSTRACT FROM AUTHOR]

Porcine thyroid cells were cultured alone or in mixed cultures with mesenchymal cells. The formation of a basal lamina in vitro was investigated ultrastructurally. Follicular reassociation of thyroid cells occurred in both types of culture; however, it was followed by formation of the basal lamina only when mesenchymal cells were present. The present findings suggest an epithelial origin of the basal lamina resulting from an interaction with mesenchymal cells. [ABSTRACT FROM AUTHOR]

Histologic and ultrastructural lesions in thyroid follicular cells of Osborne-Mendel rats produced by feeding diets containing 5, 50, and 500 ppm polychlorinated biphenyls (PCB) for 4 weeks were compared with alterations produced by low (Remington diet) and high (1%KI) iodide diets, chronic thyroxine administration, and a single injection of thyrotropin. Exposure to PCB resulted in a dose-dependent hypertrophy and hyperplasia of follicular cells with an abnormal accumulation of large colloid droplets and irregular lysosomes. There was limited evidence of colloid droplet-lysosome interaction necessary for the secretion of thyroid hormones. Microvilli on luminal surfaces were decreased, abnormally shaped, and short. Serum thyroxine and triiodothyronine were decreased significantly after feeding PCB. Follicular cells in rats fed the iodine-deficient diet underwent hypertrophy and hyperplasia with increased development of rough endoplasmic reticulum. They had increased numbers of round lysosomes and colloid droplets. There were numerous uniformly long microvilli and occasional pseudopodia were present engulfing colloid. Serum thyroxine was significantly decreased but triiodothyronine levels were increased. The iodide-excess diet resulted in hypertrophy and hyperplasia of follicular cells which contained numerous colloid droplets and abnormally shaped lysosomes with little evidence of fusion. Numerous long microvilli extended into the lumen. Many follicular cells contained unique intracytoplasmic microfollicles lined by uniform microvilli. Serum thyroxine was significantly reduced. Follicular cells of rats chronically administered thyroxine underwent involution and had only a few short microvilli, scattered round lysosomes, and poorly developed organelles. Serum thyroxine and triiodothyronine were elevated significantly. Thyrotropin (TSH) produced hypertrophy of follicular cells by 30 min post-injection with increased large colloid droplets and small round lysosomes. Large pseudopod-like projections of follicular cells were involved in endocytosis of colloid. There was evidence of fusion of lysosomal membranes with colloid droplets. Circulating thyroid hormone levels were significantly elevated from 30 min to 8 h after administration of thyrotropin but normal by 24 h. The ultrastructural alterations produced by PCB in the luminal plasma membrane and structure of microvilli were distinct from changes observed with acute stimulation by TSH, long-term stimulation by iodide excess or deficient diets, and chronic suppression by thyroxine. The changes in lysosomal structure and the accumulation of colloid droplets with little evidence of fusion in follicular cells of rats fed PCB closely resembled the findings in rats fed the iodide-excess diet. The principal effect of PCB on follicular cells appeared to be on limiting colloid droplet-lysosome interaction thereby inhibiting the proteolysis of thyroglobulin necessary for the release of thyroid hormones. [ABSTRACT FROM AUTHOR]

We aimed to investigate the role of programmed cell death protein 1 (PD-1) and T lymphocytes in the proliferation, apoptosis and secretion of cells from patients and mice with Graves' disease (GD). The levels of serum hormones, related antibodies and inflammatory cytokines in GD patients were determined by electrochemiluminescence immunoassay and ELISA. The percentages of CD4 and CD8 T-lymphocytes and PD-1 expression were examined by flow cytometry. A GD mouse model, a thyroid follicular epithelial cell, and a CD4+PD-1+, CD4+PD-1- and CD8+PD-1+, CD8+PD-1- T lymphocyte co-culture system were constructed. The viability, apoptosis-related markers, serum hormones, related antibodies and inflammatory cytokines in thyroid follicular epithelial cells were determined by CCK-8, Western blot, qTR-PCR, electrochemiluminescence immunoassay and ELISA. Elevated free thyroid hormones (FT3, FT4), thyroid hormone antibodies (TRAb, TPOAb and TGAb), inflammatory cytokines, and inhibited TSH were observed in GD patients. The percentage of CD4 + T cells was increased, while that of CD8 + T cells was reduced in GD patients. PD-1 expression level was lifted in both CD4 + and CD8 + cells from GD patients. In mouse thyroid follicular epithelial cells co-cultured with CD4 + PD-1 + and CD8 + PD-1 + T lymphocytes, the cell viability, TH and TRAb levels and inflammatory cytokines level were the highest, while the TSH level and apoptosis were the lowest. PD-1 positive T lymphocytes were able to promote viability and inhibit apoptosis of thyroid follicular epithelial cells, which further caused a more accelerated development of GD.