The pathogenesis of thyroid autoimmune diseases: New T lymphocytes – Cytokines circuits beyond the Th1−Th2 paradigm

Unraveling the molecular architecture of autoimmune thyroid diseases at spatial resolution

Autoimmune thyroid diseases (AITD) such as Graves' disease (GD) or Hashimoto's thyroiditis (HT) are organ-specific diseases that involve complex interactions between distinct components of thyroid tissue. Here, we use spatial transcriptomics to explore the molecular architecture, heterogeneity and location of different cells present in the thyroid tissue, including thyroid follicular cells (TFCs), stromal cells such as fibroblasts, endothelial cells, and thyroid infiltrating lymphocytes. We identify damaged antigen-presenting TFCs with upregulated CD74 and MIF expression in thyroid samples from AITD patients. Furthermore, we discern two main fibroblast subpopulations in the connective tissue including ADIRF+ myofibroblasts, mainly enriched in GD, and inflammatory fibroblasts, enriched in HT patients. We also demonstrate an increase of fenestrated PLVAP+ vessels in AITD, especially in GD. Our data unveil stromal and thyroid epithelial cell subpopulations that could play a role in the pathogenesis of AITD.

Experimental rat models for Hashimoto's thyroiditis

PURPOSE

Hashimoto's thyroiditis (HT) is an autoimmune thyroid disease characterized by T lymphocyte-mediated destruction of thyroid follicles. To study the pathogenesis of HT and the efficacy of new substances for its treatment, an easily obtained and adequate to the human disease experimental model is needed. The aim of our study was to find out whether it is possible to induce experimental autoimmune thyroiditis (EAT) similar to Hashimoto's thyroiditis by injecting with thyroglobulin (Tg) without using agents that enhance its thyroiditogenicity and without taking into account the genetic sensitivity of animals.

METHODS

Wistar rats were immunized with freshly isolated rat Tg or porcine Tg. In 8 weeks, histological studies of the thyroid and parathyroid glands were performed. Thyroid function and total serum calcium level were also evaluated.

RESULTS

Immunization with both rat and porcine freshly isolated Tg caused T lymphocytic infiltration of the thyroid gland, thyroid follicle atrophy and degradation in Wistar rats. EAT caused by porcine Tg was characterized by greater severity than EAT induced with rat Tg. In 55% of rats with porcine Tg-induced EAT, oxyphilic metaplasia was detected in the parathyroid glands. In addition, low total serum calcium was observed in these rats.

CONCLUSION

Two rat models of autoimmune thyroiditis were obtained. EAT caused in Wistar rats by immunization with rat Tg is similar to Hashimoto's thyroiditis. EAT induced with porcine Tg was accompanied by oxyphil cell metaplasia in the parathyroids and hypocalcemia.

Clinical efficacy and molecular mechanism of Chinese medicine in the treatment of autoimmune thyroiditis

ETHNOPHARMACOLOGICAL RELEVANCE

Autoimmune Thyroiditis (AIT) is a common refractory autoimmune disease of the endocrine system that may eventually lead to complete loss of thyroid function, with subsequent severe effects on the metabolism. Because of the deficiency in current clinical management of AIT, the need for alternative therapies is highlighted. With its multi-component and multi-target characteristics, Chinese medicine has good potential as an alternative therapy for AIT.

AIM OF THE STUDY

The aim of this study was to systematically summarize the clinical efficacy and safety evaluation of TCM and its active ingredients in the treatment and regulation of AIT. Additionally, we provide an in-depth discussion of the relevant mechanisms and molecular targets to understand the protective effects of traditional Chinese medicine on AIT and explore new ideas for clinical treatment.

MATERIALS AND METHODS

The literature related to "Hashimoto", "autoimmune thyroiditis", "traditional Chinese medicine," and "Chinese herbal medicine" was systematically summarized and reviewed from Web of Science Core Collection, PubMed, CNKI, and other databases. Domestic and international literature were analyzed, compared, and reviewed.

RESULTS

An increasing number of studies have demonstrated that herbal medicines can intervene in immunomodulation, with pharmacological effects such as antibody lowering, anti-inflammatory, anti-apoptotic thyroid follicular cells, regulation of intestinal flora, and regulation of estrogen and progesterone levels. The signaling pathways and molecular targets of the immunomodulatory effects of Chinese herbal medicine for AIT may include Fas/FasL, Caspase, BCL-2, and TLRs/MyD88/NF-κB et al. CONCLUSIONS: The use of Chinese herbs in the treatment and management of AIT is clinically experienced, satisfactory, and safe. Future studies may evaluate the influence of herbal medicines on the occurrence and development of AIT by modulating the interaction between immune factors and conventional signaling pathways.

Causal relationship between inflammatory cytokines and autoimmune thyroid disease: a bidirectional two-sample Mendelian randomization analysis

Background

Autoimmune thyroid disease (AITD) ranks among the most prevalent thyroid diseases, with inflammatory cytokines playing a decisive role in its pathophysiological process. However, the causal relationship between the inflammatory cytokines and AITD remains elusive.

Methods

A two-sample Mendelian randomization (MR) analysis was performed to elucidate the causal connection between AITD and 41 inflammatory cytokines. Genetic variations associated with inflammatory cytokines were sourced from the FinnGen biobank, whereas a comprehensive meta-analysis of genome-wide association studies (GWASs) yielded data on Graves' disease (GD) and Hashimoto thyroiditis. Regarding the MR analysis, the inverse variance-weighted, MR-Egger, and weighted median methods were utilized. Additionally, sensitivity analysis was conducted using MR-Egger regression, MR-pleiotropy residual sum, and outliers.

Results

Seven causal associations were identified between inflammatory cytokines and AITD. High levels of tumor necrosis factor-β and low levels of stem cell growth factor-β were indicative of a higher risk of GD. In contrast, high levels of interleukin-12p70 (IL-12p70), IL-13, and interferon-γ and low levels of monocyte chemotactic protein-1 (MCP-1) and TNF-α suggested a higher risk of HD. Moreover, 14 causal associations were detected between AITD and inflammatory cytokines. GD increases the levels of macrophage inflammatory protein-1β, MCP-1, monokine induced by interferon-γ (MIG), interferon γ-induced protein 10 (IP-10), stromal cell-derived factor-1α, platelet-derived growth factor BB, β-nerve growth factor, IL-2ra, IL-4, and IL-17 in blood, whereas HD increases the levels of MIG, IL-2ra, IP-10, and IL-16 levels.

Conclusion

Our bidirectional MR analysis revealed a causal relationship between inflammatory cytokines and AITD. These findings offer valuable insights into the pathophysiological mechanisms underlying AITD.

Association of autoimmune thyroid disease with type 1 diabetes mellitus and its ultrasonic diagnosis and management

As a common hyperglycemic disease, type 1 diabetes mellitus (T1DM) is a complicated disorder that requires a lifelong insulin supply due to the immune-mediated destruction of pancreatic β cells. Although it is an organ-specific autoimmune disorder, T1DM is often associated with multiple other autoimmune disorders. The most prevalent concomitant autoimmune disorder occurring in T1DM is autoimmune thyroid disease (AITD), which mainly exhibits two extremes of phenotypes: hyperthyroidism [Graves' disease (GD)] and hypo-thyroidism [Hashimoto's thyroiditis, (HT)]. However, the presence of comorbid AITD may negatively affect metabolic management in T1DM patients and thereby may increase the risk for potential diabetes-related complications. Thus, routine screening of thyroid function has been recommended when T1DM is diagnosed. Here, first, we summarize current knowledge regarding the etiology and pathogenesis mechanisms of both diseases. Subsequently, an updated review of the association between T1DM and AITD is offered. Finally, we provide a relatively detailed review focusing on the application of thyroid ultrasonography in diagnosing and managing HT and GD, suggesting its critical role in the timely and accurate diagnosis of AITD in T1DM.

Alterations in CD4+ T Cell Cytokines Profile in Female Patients with Hashimoto's Thyroiditis Following Vitamin D Supplementation: A Double-blind, Randomized Clinical Trial

BACKGROUND

Hashimoto's thyroiditis (HT) is an autoimmune disease characterized by the destruction of thyroid cells through immune processes involving T helper (Th)1 cytokines. This clinical trial investigates the impact of vitamin D supplementation on serum cytokine levels and gene expression in CD4+ T cells from HT patients, aiming to understand its effects on Th-1, Th-2, Th-17, and regulatory T (Treg) cell-associated factors.

METHODS

Female patients were randomly assigned in a double-blind design to either a vitamin D-supplemented group, which received cholecalciferol (1, 25(OH)2D3) at a dose of 50,000 IU, or the placebo group, which received a weekly placebo for a duration of three months. Serum cytokine levels were assessed using enzyme-linked immunosorbent assay (ELISA), while genes' expression levels were measured using real-time PCR.

RESULTS

Serum 25-hydroxyvitamin D and levels exhibited a significant increase following vitamin D supplementation, in comparison to the placebo group. Additionally, the vitamin D supplementation resulted in a significant elevation of serum calcium (Ca) levels compared to baseline. In the vitamin D group, there was a significant decrease in both serum levels and expression of the interleukin (IL)-17 gene when compared to baseline, although no statistical difference was observed between the placebo and vitamin D groups. The gene expression of transforming growth factor-beta (TGFβ) was significantly increased in the vitamin D group compared to baseline, with no significant difference between the two study groups. Vitamin D treatment had no effect on serum levels of interferon-gamma (IFNϒ) and IL-4. While the gene expression of IL-4 in the vitamin D group did not exhibit a statistically significant increase, the level of GATA3 transcription factor increased significantly when compared to the placebo group. The expression of IFNϒ and transcription factors, T-bet, RORc, and forkhead box protein 3 (FOXP3) in genes did not show significant changes following vitamin D supplementation.

CONCLUSION

The findings suggest that vitamin D supplementation may hold potential benefits for autoimmune diseases, such as HT. However, further longitudinal clinical trials are necessary to gain a more comprehensive understanding of the specific effects of vitamin D on HT.

Interleukin (IL)-23, IL-31, and IL-33 Play a Role in the Course of Autoimmune Endocrine Diseases

BACKGROUND

Interleukins (IL)-23, 31, and 33 are involved in the regulation of T helper 17 (Th17)/regulatory T (Treg) cells balance. The role of IL-23, 31 and 33 in non-endocrine autoimmune diseases has been confirmed. Data on the involvement of these cytokines in endocrine autoimmune diseases are limited.

OBJECTIVE

This study aimed to determine the involvement of cytokines regulating the T helper 17 (Th17)/regulatory T (Treg) cells axis in the course of autoimmune endocrine diseases.

METHODS

A total number of 80 participants were divided into 4 groups: the autoimmune polyendocrine syndrome (APS) group consisting of APS type 2 (APS-2) and type 3 (APS-3) subgroups, the Hashimoto's thyroiditis (HT) group, the Graves' disease (GD) group and the control (C) group. Fifteen cytokines related to Th17 and Treg lymphocytes were determined in the serum of all participants.

RESULTS

Higher levels of IL-23 and IL-31 were found in the APS, GD, and HT groups compared to the C group. Higher levels of IL-23 and IL-31 were also observed in the APS-2 group, in contrast to the APS-3 group. Correlation analysis of variables in the groups showed a statistically significant correlation between the cytokines IL-23, IL-31, and IL-33 in the APS and APS-2 groups, but no correlation in the APS-3 and C groups.

CONCLUSION

IL-23 and IL-31 are independent factors in the course of HT, GD, and APS-2, in contrast to APS-3. The positive correlation between IL-23 and IL-31, IL-23 and IL-33, and between IL-31 and IL-33 in the APS, APS-2 groups, but the lack of correlation in the APS-3 and C groups may further suggest the involvement of these cytokines in the course of Addison's disease.

A Review of Thyroid Dysfunction Due to COVID-19

Coronavirus disease 2019 (COVID-19) affects thyroid function. These changes are due to the direct impact of the virus on thyroid cells via angiotensin-converting-enzyme 2 (ACE2) receptors, inflammatory reaction, apoptosis in thyroid follicular cells, suppression of hypothalamus-pituitarythyroid axis, an increase in activity of adrenocortical axis, and excess cortisol release due to cytokine storm of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Euthyroid sick syndrome (ESS), thyroiditis, clinical and subclinical hypothyroidism, central hypothyroidism, exacerbation of underlying autoimmune thyroid disease, and clinical and subclinical hyperthyroidism can be associated with coronavirus. Adjuvants in coronavirus vaccines induce autoimmune/inflammatory syndrome known as vaccine adjuvants (ASIA) syndrome. Thyroiditis and Graves' disease have been reported to be associated with ASIA syndrome after some coronavirus vaccinations. Some coronavirus medications, such as hydroxychloroquine, monoclonal antibodies, lopinavir/ritonavir, remdesivir, naproxen, anticoagulants, and glucocorticoids can also affect thyroid tests, and correct diagnosis of thyroid disorders will be more difficult. Changes in thyroid tests may be one of the most important manifestations of COVID-19. These changes can be confusing for clinicians and can lead to inappropriate diagnoses and decisions. Prospective studies should be conducted in the future to increase epidemiological and clinical data and optimize the management of thyroid dysfunctions in patients with COVID-19.

A Case of Polymyositis Associated with Cytomegalovirus Infection in a Patient with Hashimoto's Thyroiditis

Polymyositis is a rare condition with an unknown etiology occurring more frequently in adult women. There is a lack of evidence on the coexistence of PM and CMV infection in a patient with hypothyroidism due to Hashimoto's Thyroiditis. However, the growing occurrence of both CMV infection and the simultaneous occurrence of autoimmune diseases points out a relationship, while the association direction remains unclear. Case outline: A 32-year-old woman recently treated for HT hypothyroidism was admitted to the hospital two weeks after being treated for common flu by the family doctor, complaining about a worsening condition with muscle pain, weakness, frequent falls, and fatigue. The first tests showed a normalized thyroid function, with elevated values of troponin and serum creatinine kinase (CK). The immunological tests revealed the presence of a high titer of CMV IgG antibodies and raised levels of CMV DNA. Pelvis MRI images demonstrated markedly elevated signals on the STIR sequences in the pelvis, thighs, and calves, indicating active and severe multifocal myositis. The diagnosis of PM was confirmed with the muscle biopsy on day 7 of hospitalization. The patient showed significant improvements within two weeks after the medical therapy and physiotherapy.

Th17 cytokines and factors modulating their activity in patients with pernicious anemia

The effects of specific cytokines produced by T cell subsets (such as Th1, Th2, and newly discovered Th17, Treg, Tfh, or Th22) are diverse, depending on interactions with other cytokines, distinct signaling pathways, phase of the disease, or etiological factor. The immunity equilibrium of the immune cells, such as the Th1/Th2, the Th17/Treg, and the Th17/Th1 balance is necessary for the maintenance of the immune homeostasis. If the balance of the T cells subsets is damaged, the autoimmune response becomes enhanced which leads to autoimmune diseases. Indeed, both the Th1/Th2 and the Th17/Treg dichotomies are involved in the pathomechanism of autoimmune diseases. The aim of the study was to determine the cytokines of Th17 lymphocytes as well as the factors modulating their activity in patients with pernicious anemia. The magnetic bead-based immunoassays used (Bio-Plex) allow simultaneous detection of multiple immune mediators from one serum sample. In our study, we showed that patients suffering from pernicious anemia develop the Th1/Th2 imbalance with a quantitative advantage of cytokines participating in Th1-related immune response, the Th17/Treg imbalance with a quantitative advantage of cytokines participating in Treg-related response, as well as the Th17/Th1 imbalance with a quantitative predominance of cytokines participating in Th1-related immune response. Our study results indicate that T lymphocytes and their specific cytokines play an role in the course of pernicious anemia. The observed changes may indicate the immune response to pernicious anemia or be an element of the pernicious anemia pathomechanism.

DBP exposure induces thyroid inflammatory impairment through activating AKT/NF-κB/NLRP3 signaling

Previous studies exhibited reproductive and neurodevelopmental toxicity in rats exposed to Di-n-butyl phthalate (DBP). However, the effects of DBP exposure on the other endocrine organ are still unclear. This study aimed to assess the impact of DBP exposure on the thyroid of male rats and the associated mechanisms. Here, rats were respectively treated with DBP at 0 (control), 50 (low dose), 250 (medium dose), or 500 (high dose) mg/kg/day dissolved in 1 ml quantity of corn oil by intragastrical administration for two weeks. The results demonstrated that the proliferation and inflammatory response changes were significantly different compared to the control. In vivo DBP is mainly converted to mono-n-butyl phthalate (MBP), an active form producing untoward reactions of DBP exposure. Therefore, for in vitro experiments, we treated the thyroid follicular epithelial cell line (Nthy-ori 3-1) in a temporal gradient using 1 mM MBP. Further in vitro studies showed that MBP exposure upregulated tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), as well as interleukin-1β (IL-1β) by activating AKT/NF-κB/NLRP3 signaling. Meanwhile, we detected that Pellino2 (Peli2) played an essential role in promoting the activation of NLRP3 inflammasome. Briefly speaking, this study confirmed that DBP exposure caused impaired thyroid structure and thyroid inflammation in male rats, which offered new views into the harm of DBP exposure on the endocrine organ.

Menstrual disturbances following COVID-19 vaccination: A probable puzzle about the role of endocrine and immune pathways

Menstruation is a monthly shedding of the uterine wall, presented by menstrual bleeding in women of reproductive age. Menstruation is regulated by fluctuation of estrogen and progesterone, as well as other endocrine and immune pathways. Many women experienced menstrual disturbances after vaccination against the novel coronavirus in the last two years. Vaccine-induced menstrual disturbances have led to discomfort and concern among reproductive-age women, such that some decided not to receive the subsequent doses of the vaccine. Although many vaccinated women report these menstrual disturbances, the mechanism is still poorly understood. This review article discusses the endocrine and immune changes following COVID-19 vaccination and the possible mechanisms of vaccine-related menstrual disturbances.

Invited review: From heat stress to disease-Immune response and candidate genes involved in cattle thermotolerance

Heat stress implies unfavorable effects on primary and functional traits in dairy cattle and, in consequence, on the profitability of the whole production system. The increasing number of days with extreme hot temperatures suggests that it is imperative to detect the heat stress status of animals based on adequate measures. However, confirming the heat stress status of an individual is still challenging, and, in consequence, the identification of novel heat stress biomarkers, including molecular biomarkers, remains a very relevant issue. Currently, it is known that heat stress seems to have unfavorable effects on immune system mechanisms, but this information is of limited use in the context of heat stress phenotyping. In addition, there is a lack of knowledge addressing the molecular mechanisms linking the relevant genes to the observed phenotype. In this review, we explored the potential molecular mechanisms explaining how heat stress affects the immune system and, therefore, increases the occurrence of immune-related diseases in cattle. In this regard, 2 relatively opposite hypotheses are under focus: the immunosuppressive action of cortisol, and the proinflammatory effect of heat stress. In both hypotheses, the modulation of the immune response during heat stress is highlighted. Moreover, it is possible to link candidate genes to these potential mechanisms. In this context, immune markers are very valuable indicators for the detection of heat stress in dairy cattle, broadening the portfolio of potential biomarkers for heat stress.

Graves' disease as a driver of depression: a mechanistic insight

Graves' disease (GD) is characterized by diffuse enlargement and overactivity of the thyroid gland, which may be accompanied by other physical symptoms. Among them, depression can dramatically damage patients' quality of life, yet its prevalence in GD has not received adequate attention. Some studies have established a strong correlation between GD and increased risk of depression, though the data from current study remains limited. The summary of mechanistic insights regarding GD and depression has underpinned possible pathways by which GD contributes to depression. In this review, we first summarized the clinical evidence that supported the increased prevalence of depression by GD. We then concentrated on the mechanistic findings related to the acceleration of depression in the context of GD, as mounting evidence has indicated that GD promotes the development of depression through various mechanisms, including triggering autoimmune responses, inducing hormonal disorders, and influencing the thyroid-gut-microbiome-brain axis. Finally, we briefly presented potential therapeutic approaches to decreasing the risk of depression among patients with GD.

Characterizing the Interplay of Lymphocytes in Graves' Disease

Graves' disease (GD) is a thyroid-specific autoimmune disease with a high prevalence worldwide. The disease is primarily mediated by B cells, which produce autoantibodies against the thyroid-stimulating hormone receptor (TSHR), chronically stimulating it and leading to high levels of thyroid hormones in the body. Interest in characterizing the immune response in GD has motivated many phenotyping studies. The immunophenotype of the cells involved and the interplay between them and their secreted factors are crucial to understanding disease progression and future treatment options. T cell populations are markedly distinct, including increased levels of Th17 and follicular helper T cells (Tfh), while Treg cells appear to be impaired. Some B cells subsets are autoreactive, and anti-TSHR antibodies are the key disease-causing outcome of this interplay. Though some consensus across phenotyping studies will be discussed here, there are also complexities that are yet to be resolved. A better understanding of the immunophenotype of Graves' disease can lead to improved treatment strategies and novel drug targets.

How does Hashimoto's thyroiditis affect bone metabolism?

Bone marrow contains resident cellular components that are not only involved in bone maintenance but also regulate hematopoiesis and immune responses. The immune system and bone interact with each other, coined osteoimmunology. Hashimoto's thyroiditis (HT) is one of the most common chronic autoimmune diseases which is accompanied by lymphocytic infiltration. It shows elevating thyroid autoantibody levels at an early stage and progresses to thyroid dysfunction ultimately. Different effects exert on bone metabolism during different phases of HT. In this review, we summarized the mechanisms of the long-term effects of HT on bone and the relationship between thyroid autoimmunity and osteoimmunology. For patients with HT, the bone is affected not only by thyroid function and the value of TSH, but also by the setting of the autoimmune background. The autoimmune background implies a breakdown of the mechanisms that control self-reactive system, featuring abnormal immune activation and presence of autoantibodies. The etiology of thyroid autoimmunity and osteoimmunology is complex and involves a number of immune cells, cytokines and chemokines, which regulate the pathogenesis of HT and osteoporosis at the same time, and have potential to affect each other. In addition, vitamin D works as a potent immunomodulator to influence both thyroid immunity and osteoimmunology. We conclude that HT affects bone metabolism at least through endocrine and immune pathways.

Correlation between the intestinal microflora and peripheral blood Th1/Th2 balance in hypothyroidism during the first half of pregnancy

Objective

This study aimed to investigate the relationship between intestinal microflora characteristics and the peripheral blood T helper cell (Th)1/Th2 balance in patients with hypothyroidism during the first half of pregnancy.

Methods

The Th1/Th2 ratios in the peripheral blood of pregnant women in the hypothyroidism and control groups were determined using flow cytometry. The cytometric bead array assay was used to determine the serum levels of interleukin-2 (IL-2), IL-4, IL-6, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ. Moreover, 16S rRNA amplicon sequencing was used to determine the intestinal microbial composition in the two groups. Finally, the relationships between intestinal microflora, Th1/Th2 cells, cytokines, and clinical indicators were analyzed.

Results

C-reactive protein levels were higher in the hypothyroidism group than in the control group. In contrast to the control group, the hypothyroidism group showed an increase in Th1 cells and the Th1/Th2 ratio, and a decrease in Th2 cells. The hypothyroidism group had higher serum IL-2, TNF-α, and IFN-γ levels, and lower IL-10 levels, than the control group. The richness of the intestinal microflora in the hypothyroidism group increased whereas the diversity decreased. The linear discriminant analysis effect size revealed that the hypothyroidism group had a higher abundance of Prevotella and Faecalibacterium, but a lower abundance of Bacteroides, compared to the control group. Prevotella was positively correlated with Th1 cells, the Th1/2 ratio, and TNF-α. Bacteroides was positively correlated with Th2 cells and IL-10, but negatively correlated with Th1 cells, the Th1/2 ratio, TNF-α, and IFN-γ. The thyroid peroxidase antibody level was directly proportional to TNF-α.

Conclusion

A Th1/Th2 imbalance occurs in patients with hypothyroidism during the first half of pregnancy. Disorders of the intestinal microflora may lead to hypothyroidism during pregnancy by affecting the Th1/Th2 balance.

Molecular Mechanisms in Autoimmune Thyroid Disease

The most common cause of acquired thyroid dysfunction is autoimmune thyroid disease, which is an organ-specific autoimmune disease with two presentation phenotypes: hyperthyroidism (Graves-Basedow disease) and hypothyroidism (Hashimoto's thyroiditis). Hashimoto's thyroiditis is distinguished by the presence of autoantibodies against thyroid peroxidase and thyroglobulin. Meanwhile, autoantibodies against the TSH receptor have been found in Graves-Basedow disease. Numerous susceptibility genes, as well as epigenetic and environmental factors, contribute to the pathogenesis of both diseases. This review summarizes the most common genetic, epigenetic, and environmental mechanisms involved in autoimmune thyroid disease.

The Role of Toll-like Receptor 2 (TLR2) in the Development and Progression of Hashimoto’s Disease (HD): A Case Study on Female Patients in Poland

Chronic lymphocytic thyroiditis, commonly known as HD, is one of the most common thyroid disorders. Due to the diverse factors affecting the etiopathogenesis of this disease (hormonal disorders and genetic and environmental factors), as well as the direct involvement of the immune system, scientists are increasingly willing to undertake research aimed at explaining the impact of the loss of immune tolerance and reactivity of autoantigens on the development of the disease. One of the directions of research in recent years is the role of the innate immune response, particularly Toll-like receptors (TLRs), in the pathogenesis of HD. The purpose of this study was to determine the importance of Toll-like receptor 2 (TLR2) expression on selected populations of immune cells, namely, monocytes (MONs) and dendritic cells (DCs), in the course of HD. Particular attention was paid to the analysis of TLR2’s correlation with clinical parameters and the possibility its use as a potential biomarker molecule in the diagnostic process. Based on the obtained results, we found a statistically significant increase in the percentage of all analyzed populations of immune cells, i.e., mDC BDCA-1+CD19−, pDC BDCA-1+CD123, classical MONs CD14+CD16−, and non-classical MONs CD14+CD16+ showing on their surface TLR2 expression in patients diagnosed with HD compared to the healthy volunteers. Moreover, in the study group, we noted a more than 6-fold increase in the concentration of the soluble form of TLR2 in plasma compared to healthy patients. In addition, the correlation analysis showed significant positive correlations between the level of TLR2 expression on selected subpopulations of immune cells and biochemical indicators of thyroid function. Based on the obtained results, we can assume that TLR2 may be involved in the immunopathogenesis of HD.

Graves' orbitopathy post-SARS-CoV-2 vaccines: report on six patients

CONTEXT

Autoimmune and inflammatory thyroid diseases (Graves' disease, subacute thyroiditis, chronic autoimmune thyroiditis) have been reported following SARS-CoV-2 vaccines but Graves' orbitopathy (GO) post-COVID-19 vaccination is uncommon.

METHODS

We describe six new patients seen in Endocrinology Departments with Outpatient Clinics for GO following SARS-CoV-2 vaccines in France.

RESULTS

After COVID-19 vaccination, GO was observed in six patients (three men, three women, mean age 53 ± 6 years) with a personal past history of Graves' disease (5/6) or orbitopathy (4/6). New-onset (n = 2) or recurrence (n = 4) of GO was observed following mRNA vaccines after the first (3/6) or second (3/6) dose, with the mean time from vaccination to GO at 23.8 ± 10.4 days. In one patient, thyrotoxicosis was confirmed by increased free T4 and low TSH concentrations while others had normal TSH levels, during chronic levothyroxine treatment in three patients. Four patients had significant anti-TSH receptor antibodies levels. According to the severity and activity of GO, the patients were treated using selenium (n = 2), intravenous glucocorticoids (n = 2), teprotumumab (n = 1), tocilizumab (n = 2) and orbital decompression (n = 1) with a significant improvement in GO signs and symptoms observed by most patients.

CONCLUSION

In this study, we report the main data from six new patients with GO following SARS-CoV-2 vaccines. Clinicians need to be aware of the risk of new-onset or recurrent GO in predisposed patients with autoimmune thyroid diseases after COVID-19 vaccination. This study should not raise any concerns regarding SARS-CoV-2 vaccination since the risk of COVID-19 undoubtedly outweighs the incidence of uncommon GO after SARS-CoV-2 vaccination.

Clinical significance of elevated serum IL-36γ levels in patients with early-stage Hashimoto's thyroiditis

OBJECTIVES

Hashimoto's thyroiditis (HT) is the predominant cause of primary hypothyroidism. Interleukin (IL)-36γ is a member of the IL-36 family. Recently, IL-36γ was shown to possess proinflammatory properties in autoimmune diseases. However, the role of IL-36γ in HT is insufficiently understood. The purpose of the present study was to investigate the potential relationship between IL-36γ and HT.

DESIGN & METHODS

We included 100 subjects, among whom, 52 had early-stage HT and 48 were healthy controls (HC). The subjects' basic clinical information was obtained through physical examination and clinical histories of signs and symptoms. Thyroid function and measurements of thyroid-stimulating hormone (TSH), free triiodothyronine 3, free triiodothyronine 4 (FT4), thyroid peroxidase antibody (TPO-Ab), and thyroid globulin antibody were measured using a fully automated chemiluminescent immunoassay analyzer. The expression levels of serum IL-36γ were determined using an enzyme-linked immunosorbent assay.

RESULTS

The serum IL-36γ level in the HT group was significantly higher compared with that of the HC group [91.91 (67.52, 130.90) pg/mL vs 62.50 (44.61, 91.53) pg/mL, P < 0.0001]. Correlation analysis showed a negative correlation between serum IL-36γ and TPO-Ab titers in the HT group (r = -0.3507, P = 0.0054). According to receiver operating characteristic curve analysis, the area under the curve (AUC) for IL-36γ was 0.7278 (P < 0.0001), and the AUC for IL-36γ combined with TSH and FT4 was 0.8109 (P < 0.0001).

CONCLUSIONS

The present study indicates that serum IL-36γ expression is increased in patients with HT and negatively correlates with TPO-Ab. Our findings suggest that IL-36γ may be involved in the development of HT and may therefore serve as a potential new diagnostic biomarker for HT.

Thyrotoxicosis after COVID-19 Infection with a Delay in Graves' Disease Antibody Positivity

Background and Objective. Mounting evidence implicates COVID-19 as a cause of thyroid dysfunction, including thyrotoxicosis due to both thyroiditis and Graves' disease (GD). In this report, we present a case of thyrotoxicosis following COVID-19 infection that was ultimately found to represent GD with significantly delayed diagnostic serum antibody positivity. Case Report. A 65-year-old woman with a history of uncomplicated COVID-19 infection one month prior, presented to the Emergency Department with exertional dyspnea and palpitations, and was found to be in atrial fibrillation with rapid ventricular response (AF with RVR). Labs showed subclinical hyperthyroidism and the patient was started on a beta-blocker and methimazole. One month later, thyroid-stimulating immunoglobulin (TSI) resulted negative and thyroid function tests had normalized. The clinical picture suggested thyroiditis, and methimazole was stopped. One month later, the patient again presented in AF with RVR, with labs showing overt biochemical thyrotoxicosis. Antibodies were re-tested, and the thyrotropin receptor antibody (TRAb) and TSI resulted positive, confirming GD. Discussion. Most notable in this case is the feature of delayed GD antibody positivity: the diagnostic immunoassay for GD resulted negative one and two months after infection, but was ultimately positive three months after infection. To the authors' knowledge, this represents the longest delayed antibody positivity reported to date, amongst cases of new-onset GD following COVID. Conclusion. The clinical course of GD following COVID-19 infection is highly variable. This case underscores the need for vigilance in monitoring for delayed GD antibody positivity due to the important therapeutic implications of distinguishing thyroiditis from GD.

Helper T Cell 17 and Regulatory T Cell Levels in Peripheral Blood of Newly Diagnosed Patients with Autoimmune Thyroid Disease: A Meta-Analysis

This article aims to explore associated immune indicators of autoimmune thyroid disease (AITD) through a meta-analysis of published case-control studies on newly diagnosed AITD patients, intending to provide some suggestions for research on the mechanisms of AITD. Six electronic databases were searched for case-control studies on newly diagnosed AITD patients from inception to August 15, 2022. A random-effects model was used to calculate the standardized mean difference (SMD), odds ratio (OR), and 95% confidence interval (95% CI). A total of 26 articles were included in this meta-analysis. Patients with newly diagnosed AITD had higher levels of helper T cell 17 (Th17) (Hashimoto's disease (HT): SMD=2.35, 95% CI: 1.98, 2.72; Graves' disease (GD): SMD=1.61, 95% CI: 1.23, 1.98), lower levels of regulatory T cell (Treg) (HT: SMD=-2.04, 95% CI: -2.67, -1.42; GD: SMD=-1.35, 95% CI: -2.11, -0.58), and lower levels of forkhead box P3 (FoxP3) mRNA (HT: SMD=-2.58, 95% CI: -3.12, -2.05; GD: SMD=-2.13, 95% CI: -2.56, -1.70), compared to the healthy population. In addition, the single nucleotide polymorphism rs3761548 and rs3761549 in the promoter region of FoxP3 showed a higher frequency in the comparison of genotype "CT" only in HT patients than in the healthy population (OR=1.66, 95%CI: 1.18, 2.34). In patients with newly diagnosed AITD, the Th17/Treg ratio imbalance may develop AITD. Monitoring Th17 and Treg levels may become an essential tool to assess the organism's immune homeostasis and hopefully guide clinical diagnosis and treatment.

Promotion of IL‑17/NF‑κB signaling in autoimmune thyroid diseases

IL-17 and other cytokines have a number of immunomodulatory effects on thyroid cells. The present study investigated the changes and correlations amongst IL-17, NF-κB, IL-6, IL-10, interferon-γ (IFN-γ), TNF-α, IL-2 and IL-4 in patients with different autoimmune thyroid diseases in order to further clarify the pathogenesis of autoimmune thyroid disease. A total of 82 patients with autoimmune thyroid diseases (41 with Graves' disease and 41 with Hashimoto's thyroiditis) and 53 healthy controls were enrolled. All relevant thyroid hormones were detected by electrochemiluminescence analyzer. The serum levels of IL-17 and other cytokines were detected using flow cytometry, NF-κB was detected by ELISA, reverse transcription-quantitative PCR was used to detect the protein expression of various mRNAs, and the correlations between IL-17 and these factors were analyzed. Significant differences occurred amongst all groups. NF-κB, TNF-α, IL-6, IL-17 and their mRNA levels were significantly higher in the healthy controls compared with those in the patients; whereas IFN-γ and IL-10 levels were significantly lower in the healthy controls compared with those in the patients . Correlation analysis showed that the expression levels of IL-17 and its mRNA were significantly positively correlated with the expression levels of NF-κB, IL-6, thyroid peroxidase antibody, thyroid gland globulin, thyroglobulin antibody, TNF-α and IFN-γ, and were also significantly negatively correlated with IL-10 . These findings suggested that IL-17 was elevated in patients with autoimmune thyroid disease and that IL-17 could activate the NF-κB signaling pathway, stimulate the production and release of inflammatory factors such as TNF-α, IL-6 and IFN-γ and participate in the pathogenesis of autoimmune thyroid injury.

Circular RNA profile in Graves' disease and potential function of hsa_circ_0090364

Background

Graves' disease is a common autoimmune disease. Cytokines and their signalling pathways play a major part in the pathogenesis of Graves' disease; however, the underlying mechanism needs to be clarified.

Aims

The aim of this study was to explore whether circular RNAs participate in the immunological pathology of Graves' disease via cytokine-related signalling pathways.

Methods

Bioinformatics analysis was performed to identify differentially expressed circular RNAs and their targets and associated pathways. A total of three patients with Graves' disease and three sex- and age-matched healthy controls were enrolled for validation with microarray analysis and real-time quantitative PCR (qPCR). An additional 24 patients with Graves' disease and 24 gender- and age-matched controls were included for validation by real-time fluorescent qPCR. Flow cytometry and CCK8 assays were used to detect the apoptotic and proliferative levels of Jurkat cells (T lymphocytes) with the silenced expression of circRNA. ELISA was performed to detect the growth and apoptosis-related proteins. The competition mechanism of endogenous RNA was explored by real-time fluorescence qPCR.

Results

A total of 366 significantly differentially expressed circular RNAs were identified in the Graves' disease group compared to healthy controls. The level of hsa_circ_0090364 was elevated in Graves' disease patients and positively correlated with thyroid-stimulating hormone receptor antibodies. Further analyses suggested that hsa_circ_0090364 may regulate the JAK-STAT pathway via the hsa-miR-378a-3p/IL-6ST/IL21R axis to promote cell growth.

Conclusions

These results provide novel clues into the pathophysiological mechanisms of Graves' disease and potential targets for drug treatment.

Comprehensive analysis of lncRNA-mediated ceRNA regulatory networks and key genes associated with papillary thyroid cancer coexistent with Hashimoto's thyroiditis

OBJECTIVE

The incidence of papillary thyroid cancer (PTC) concomitant with Hashimoto's thyroiditis (HT) is gradually increasing over the past decades. This study aims to identify differentially expressed lncRNAs between tumor tissues of PTC with or without HT and further to confer a better understanding of lncRNA-based competing endogenous RNA (ceRNA) network in PTC with HT.

METHODS

GSE138198 containing tissue mRNA data and GSE192560 containing lncRNA data were utilized to perform differentially expression analysis. The ceRNA network was constructed based on miRNA-mRNA interactions merging with lncRNA-microRNA interactions. Functional enrichment analysis and protein-protein interaction (PPI) analysis were performed. The mRNA levels of core genes in the PPI analysis in tumor tissues collected from 112 PTC patients including 35 cases coexistent with HT were determined by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

A total of 57 genes and 40 lncRNAs, with value of |log2 fold change (FC)|≥ 1 and the adjusted P-value < 0.05, were deemed as differentially expressed genes and lncRNAs between PTC with and without HT. The pathways most significantly enriched by differentially expressed genes between PTC with and without HT were viral protein interaction with cytokine and cytokine receptor and cytokine-cytokine receptor interaction. CXCL10, CXCL9, CCL5, FCGR3A, and CCR2 owned degree values not less than 10 were deemed as core genes differentially expressed between PTC with and without HT. A total of 76 pairs of lncRNA-miRNA-mRNA ceRNA were obtained. Results of qRT-PCR partially demonstrated the bioinformatics results that the mRNA levels of CXCL10, CXCL9, CCL5, and CCR2 were remarkably elevated in tumor tissues collected from PTC patients coexistent with HT than those without HT (P < 0.001).

CONCLUSION

Our study offers a better understanding of the lncRNA-related ceRNA network involved in PTC with HT, providing novel key genes associated with PTC coexistent with HT.

High iodine promotes autoimmune thyroid disease by activating hexokinase 3 and inducing polarization of macrophages towards M1

Autoimmune thyroid disease (AITD), the most common autoimmune disease, includes Graves’ disease (GD) and Hashimoto’s thyroiditis (HT). Currently, the pathogenesis of AITD is not fully understood. Our study aimed to examine the presence of macrophage polarization imbalance in AITD patients, to investigate whether high iodine can cause macrophage polarization imbalance, and to investigate the role of key genes of metabolic reprogramming in macrophage polarization imbalance caused by high iodine. We synergistically used various research strategies such as systems biology, clinical studies, cell culture and mouse disease models. Gene set enrichment analysis (GSEA) revealed that M1 macrophage hyperpolarization was involved in the pathogenesis of AITD. In vitro and in vivo experiments showed that high iodine can affect the polarization of M1 or M2 macrophages and their related cytokines. Robust rank aggregation (RRA) method revealed that hexokinase 3 (HK3) was the most aberrantly expressed metabolic gene in autoimmune diseases. In vitro and in vivo studies revealed HK3 could mediate macrophage polarization induced by high iodine. In summary, hyperpolarization of M1-type macrophages is closely related to the pathogenesis of AITD. High iodine can increase HK3 expression in macrophages and promote macrophage polarization towards M1. Targeting HK3 can inhibit M1 polarization induced by high iodine.

HLA-DRA Gene Polymorphisms Are Associated with Graves’ Disease as an Autoimmune Thyroid Disease

Background

Autoimmune thyroid disease (AITD), one of the most prevalent organ-specific autoimmune diseases, mainly includes Graves' disease (GD) and Hashimoto's thyroiditis (HT). This study was aimed at researching the association between AITD and single nucleotide polymorphisms (SNPs) of the HLA-DRA gene.

Methods

Using Hi-SNP high-throughput sequencing technology, we detected the distribution of three SNPs (rs3177928, rs7197, and rs3129878) of HLA-DRA genotypes in 1033 AITD patients (634 GD and 399 HT ones) and 791 healthy volunteers in Chinese Han Population. Chi-square test, multivariate logistic regression, and haplotype analysis were performed by SPSS and Haploview software to analyze the relationship between HLA-DRA gene polymorphisms and AITD.

Results

The results show that allele frequency and genotype distribution of rs3177928 and rs7197 were correlated with AITD and GD compared with the healthy control group, but not with HT. Rs3177928 and rs7197 were correlated with AITD and HT in the allele model, dominant model, and overdominant model before and after gender and age adjustment, but not with HT. In addition, we found that two loci (rs3177928 and rs7197) constituted a linkage disequilibrium (LD) region, and haplotype AA was associated with AITD and GD. However, we found no association between rs3129878 and AITD.

Conclusion

Our study is the first to find that rs3177928 and rs7197 of HLA-DRA are significantly correlated with AITD and GD in the Chinese Han population. This will help further reveal the pathogenesis of AITD and provide new candidate genes for the prediction or treatment of AITD.

Hyperthyroidism and clinical depression: a systematic review and meta-analysis

Hyperthyroidism and clinical depression are common, and there is preliminary evidence of substantial comorbidity. The extent of the association in the general population, however, has not yet been estimated meta-analytically. Therefore we conducted this systematic review and meta-analysis (registered in PROSPERO: CRD42020164791). Until May 2020, Medline (via PubMed), PsycINFO, and Embase databases were systematically searched for studies on the association of hyperthyroidism and clinical depression, without language or date restrictions. Two reviewers independently selected epidemiological studies providing laboratory or ICD-based diagnoses of hyperthyroidism and diagnoses of depression according to operationalized criteria (e.g. DSM) or to cut-offs in established rating scales. All data, including study quality based on the Newcastle-Ottawa Scale, were independently extracted by two authors. Odds ratios for the association of clinical depression and hyperthyroidism were calculated in a DerSimonian-Laird random-effects meta-analysis. Out of 3372 papers screened we selected 15 studies on 239 608 subjects, with 61% women and a mean age of 50. Relative to euthyroid individuals, patients with hyperthyroidism had a higher chance of being diagnosed with clinical depression: OR 1.67 ([95% CI: 1.49; 1.87], I²: 6%; prediction interval: 1.40 to 1.99), a result supported in a number of sensitivity and subgroup analyses. The OR was slightly less pronounced for subclinical as opposed to overt hyperthyroidism (1.36 [1.06; 1.74] vs. 1.70 [1.49; 1.93]). This comorbidity calls for clinical awareness and its reasons need investigation and may include neurobiological mechanisms, common genetic vulnerability and a generally heightened risk for clinical depression in patients with chronic somatic disorders.

IL-33/ST2 axis in autoimmune disease

Interleukin-33 (IL-33) is a member of the IL-1 family and plays an ambivalent role in autoimmune diseases. IL-33 signals via the ST2 receptor and drives cytokine production in mast cells, basophils, eosinophils, NK cells, and T lymphocyte cells. The vital role of IL-33 as an active component gives rise to aberrant local and systemic damage which has been demonstrated in numerous inflammatory disorders and immune-mediated pathological conditions including multiple sclerosis (MS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriasis, Sjogren's syndrome, inflammatory bowel disease (IBD), etc. IL-33/ST2 axis can up-regulate pro-inflammatory cytokine release in autoimmune disease, however, in some metabolic diseases like diabetes mellitus type 1 IL-33 can be considered an anti-inflammatory cytokine. The purpose of this review is to discuss selected studies on IL-33/ST2 axis in autoimmune diseases and its potential role as a pathogenic or protective cytokine.

Role of Nuclear Factor Erythroid 2 (Nrf2) in the Recovery of Long COVID-19 Using Natural Antioxidants: A Systematic Review

Coronavirus disease 2019 (COVID-19) is an infectious disease with approximately 517 million confirmed cases, with the average number of cases revealing that patients recover immediately without hospitalization. However, several other cases found that patients still experience various symptoms after 3–12 weeks, which is known as a long COVID syndrome. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can activate nuclear factor kappa beta (NF-κβ) and unbind the nuclear factor erythroid 2-related factor 2 (Nrf2) with Kelch-like ECH-associated protein 1 (Keap1), causing inhibition of Nrf2, which has an important role in antioxidant response and redox homeostasis. Disrupting the Keap1–Nrf2 pathway enhances Nrf2 activity, and has been identified as a vital approach for the prevention of oxidative stress and inflammation. Hence, natural antioxidants from various sources have been identified as a promising strategy to prevent oxidative stress, which plays a role in reducing the long COVID-19 symptoms. Oxygen-rich natural antioxidant compounds provide an effective Nrf2 activation effect that interact with the conserved amino acid residues in the Keap1-binding pocket, such as Ser602, Ser363, Ser508, and Ser555. In this review, the benefits of various natural antioxidant compounds that can modulate the Nrf2 signaling pathway, which is critical in reducing and curing long COVID-19, are highlighted and discussed.

High-throughput DNA methylation analysis in ITP confirms NOTCH1 hypermethylation through the Th1 and Th2 cell differentiation pathways

BACKGROUND

Immune thrombocytopenia (ITP) is a prevalent autoimmune disease with a complex aetiology where DNA methylation changes are becoming triggers.

METHOD

To investigate novel abnormally methylated genes in the pathogenesis of ITP, we performed a high-throughput methylation analysis on 21 ITP patients and 9 normal control samples. We analysed the extent of key methylated genes and their downstream cytokines through Luminex assay or qRT-PCR. Then, bone marrow mononuclear cells were extracted from ITP patients, and decitabine (demethylation drug) was added to the culture medium of cultured cells. qRT-PCR and ELISA were used to detect whether decitabine could effectively affect target genes and related cytokines.

RESULTS

Through the STRING and Metascape databases, hypermethylated NOTCH1 can be identified and can influence ITP by regulating many downstream cytokines through Th1 and Th2 cell differentiation pathways. Compared with those in the normal control group, the expression levels of NOTCH1 and its downstream Th2 cytokines (IL-4, IL-10, and GATA3) were significantly decreased and those of Th1 cytokines (IFN-γ, IL-12, and TNF-α) were significantly increased in the ITP group. Decitabine exerts its demethylation effect, so the expression of NOTCH1 and its related cytokines in the ITP group treated with 100 nM decitabine were significantly reversed.

CONCLUSIONS

Our results suggest that the pathogenesis of ITP may exert its influence on epigenetics through alteration of DNA methylation at regulatory regions of the target NOTCH1 gene in the Th1 and Th2 cell differentiation pathways. At the same time, decitabine may achieve a therapeutic effect on ITP by demethylation.

A Global Regulatory Network for Dysregulated Gene Expression and Abnormal Metabolic Signaling in Immune Cells in the Microenvironment of Graves' Disease and Hashimoto's Thyroiditis

Background

Although the pathogenetic mechanisms of Hashimoto’s thyroiditis (HT) and Graves’ disease (GD) have been elucidated, the molecular mechanisms by which the abnormal immune function of cellular subpopulations trigger an autoimmune attack on thyroid tissue largely remains unexplained.

Methods

The study included 2 HT patients, 2 GD patients, and 1 control donor. The thyroid samples were extracted for single-cell RNA sequencing, whole transcriptome, full-length transcriptome (Oxford Nanopore Technologies), and metabolome sequencing. Identification of immune cells with dysregulated gene expression and abnormal metabolic signaling was performed in the microenvironment, both at the bulk and single-cell levels. Based on functional enrichment analysis, the biological processes and pathways involved in abnormal immune cells were further explored. Finally, according to cell communication analysis, the global regulatory network of immune cells was constructed.

Results

CD4⁺ T cells, CD8⁺ T cells, and macrophages were abnormally increased in patients with HT and GD. The differentially expressed genes of these cells were significantly involved in signaling pathways, including Th1 and Th2 cell differentiation, Th17 cell differentiation, cytokine–cytokine receptor interaction, and NF-kappa B signaling pathway. Moreover, in HT, CD4⁺ T cells interact with macrophages via the IL16-CCR5/FGF10-FGFR1/CXCL13-CXCR3 axis, and macrophages interact with CD8⁺ T cells via the CD70-CD27 axis, thereby activating the T-cell receptor signaling pathway and NF-kappa B signaling pathway. In GD, CD4⁺ T cells interact with macrophages via the CXCR3-CXCL10/PKM-CD44/MHCII-NFKBIE axis, and macrophages interact with CD8⁺ T cells via the IFNG-IFNGR1/CCR7-CCL21 axis, thereby activating T-cell receptor signaling pathway, Th1 and Th2 cell differentiation, and chemokine signaling pathway.

Conclusion

In HT and GD, immune dysregulated cells interact and activate relevant immune pathways and further aggravate the immune response. This may trigger the immune cells to target the thyroid tissue and influence the development of the disease.

HDAC6-specific inhibitor alleviates hashimoto's thyroiditis through inhibition of Th17 cell differentiation

OBJECTIVE

Hashimoto's thyroiditis (HT) is one of the commonest autoimmune disorders. This study was performed to investigate the potential effect of histone deacetylase 6-specific inhibitor (HDAC6i) on Th17 cell differentiation in animal model and the underlying mechanism.

METHODS

Experimental autoimmune thyroiditis (EAT) mouse model was established by subcutaneously immunization of porcine thyroglobulin (pTg) and adjuvant, and the HDACi Tubastatin A (TSA) or HDAC6i (ACY-1215) was intraperitoneally injected into mice in the following. The histological examination and immune analysis in EAT mice were carried out. Next, the CD4+ T cells were isolated from peripheral blood mononuclear cells (PBMCs) of EAT mice followed by Th17 cell differentiation assay. The associated factor levels, and the protein interaction between HDAC6 and PKM2 were examined. Subsequently, the effect of STAT3 activation on Th17 cell differentiation was explored.

RESULTS

ACY-1215 or TSA treatment reduced lymphocytic infiltration and alleviated thyroid tissue injury in EAT mice. Correspondingly, either ACY-1215 or TSA treatment reduced the levels of anti-thyroglobulin (Tg), anti-thyroid peroxidase (TPO), IL-17A, and IFN-γ in the serum, decreased Th17 cell differentiation, but enhanced TGF-β level and promoted Treg cell differentiation. In vitro, after induction of Th17 cell differentiation from CD4+ T cells, HDAC6 activity and Th17 cell differentiation were significantly decreased when treated with ACY-1215 or TSA. HDAC6 could interact with PKM2, and HDAC6 overexpression promoted the phosphorylation of STAT3 and PKM2 nuclear translocation. Furthermore, the STAT3 activator treatment reversed the effects of ACY-1215 or TSA treatment.

CONCLUSION

HDAC6i suppresses Th17 cell differentiation and attenuates HT via PKM2/STAT3 axis.

The role of transforming growth factor beta in thyroid autoimmunity: current knowledge and future perspectives

The complex mechanisms, which are related to the pathophysiology and the development of autoimmune thyroid diseases, involve transforming growth factor beta (TGF-β) and its interplay with the immune system. The aim of this review is to examine the role of TGF-β regarding thyroid autoimmunity and explore the potent role of this molecule either as a diagnostic or prognostic marker or a therapeutic target regarding autoimmune thyroid diseases. TGF-β is clearly a master regulator of the immune response, exerting either inhibitory or facilitatory effects on cells of the immune system. Thus, this molecule is involved in the pathogenesis and development of autoimmune thyroid diseases. Recent research has revealed the involvement of TGF-β in the pathophysiology of autoimmune thyroid diseases. The role of TGF-β in the development of autoimmune thyroid diseases varies, depending on its concentrations, the type of the activated TGF-β signalling pathway, the genetic predisposition of the patient and the pathophysiologic stage of the disease. TGF-β could emerge as a useful diagnostic or prognostic marker for the evolution of thyroid autoimmunity. Promising perspectives for the effective therapeutic use of TGF-β regarding thyroid autoimmunity exist. The main treatment approaches incorporate either enhancement of the immunosuppressive role of TGF-β or inhibition of its facilitatory role in the autoimmune thyroid diseases. Further research towards deeper understanding of TGF-β physiology and clinical application of its possible therapeutic role regarding thyroid autoimmunity is needed.

Effects of Fisetin on Allergic Contact Dermatitis via Regulating the Balance of Th17/Treg in Mice

Background. Allergic contact dermatitis (ACD) is a form of chronic cutaneous inflammatory disease of immunological origin that has adverse impacts on patient quality of life, underscoring the need for the development of safe and effective therapeutic agents to treat affected individuals. Fisetin is a Chinese herbal preparation that reportedly exhibits antitumor, antioxidant, antimicrobial, anticoagulatory, and antimalarial activity. In the current report, the immunomodulatory activity of fisetin was appraised by assessing its impact on balance between regulatory T (Treg) and Th17 cells in an ACD model. Methods. BALB/c mice ( $n=60$ ) were randomized into control, ACD model, CTX positive control (20 mg/kg), and fisetin treatment groups (three dose levels: 2, 4, or 8 mg/kg). ACD induction was achieved by sensitizing mice on the shaved ventral abdomen via the application of 5% DNFB (50 μL) on days 1 and 2, followed by rechallenge in the right ear with 5% DNFB (20 μL) on day 5. Beginning on day 1, immunized mice were intraperitoneally injected with the appropriate fisetin dose (in saline) once per day for 7 days. On day 7, ear swelling, transcription factor expression, Th17/Treg cell populations, and cytokine production were assessed in vivo. Results. Fisetin treatment significantly suppressed ear swelling and associated inflammatory cell infiltration, besides reducing the production of Th17 cytokines (IL-17, TNF-α, and IL-6) and the expression of the Th17 lineage transcription factor RORγt while simultaneously enhancing Treg-specific cytokine production (TGF-β and IL-10) and the expression of the Treg lineage transcription factor Foxp3, thereby restoring the Th17/Treg cell in ACD mice. Conclusions. These data indicate that fisetin exhibits immunomodulatory activity and can alter the Th17/Treg cell balance, highlighting its potential value as a treatment drug for ACD.

Gut Microbiome and the Role of Metabolites in the Study of Graves’ Disease

Graves’ disease (GD) is an autoimmune thyroid disease (AITD), which is one of the most common organ-specific autoimmune disorders with an increasing prevalence worldwide. But the etiology of GD is still unclear. A growing number of studies show correlations between gut microbiota and GD. The dysbiosis of gut microbiota may be the reason for the development of GD by modulating the immune system. Metabolites act as mediators or modulators between gut microbiota and thyroid. The purpose of this review is to summarize the correlations between gut microbiota, microbial metabolites and GD. Challenges in the future study are also discussed. The combination of microbiome and metabolome may provide new insight for the study and put forward the diagnosis, treatment, prevention of GD in the future.

COVID-19-Induced Graves’ Disease

COVID-19, a multi-system disease, could potentially play a role in thyroid dysfunction. New reports show a prevalence of COVID-related thyroiditis. Recent studies suggest that there may be a higher risk of thyroiditis in the setting of SARS-CoV-2, and several cases of Graves’ disease have been reported in individuals with SARS-CoV-2, although the incidence of such findings and their relationship to COVID-19 is unknown. In this report, we present Graves’ hyperthyroidism in a 48-year-old African American male who was admitted to the hospital for complaints of cough, fatigue, and palpitations. He tested positive for SARS-CoV-2 and was found to have suppressed thyroid-stimulating hormone (TSH) and an elevated free T4. The patient had no prior history of thyroid disease. Initially, it was thought to be a case of viral thyroiditis, and he was discharged on prednisone. However, he was found to have positive thyroid-stimulating immunoglobulin (TSI) and a diffuse increase in flow on doppler ultrasound of the thyroid. Subsequently, he was started on anti-thyroid medications with significant improvement. What is unique about this case is that, unlike other described cases in the literature where there was a relapse of a known Graves' disease after COVID-19 disease, our patient did not have a history or symptoms of thyroid disease prior to this event, which should raise the concern about possible activation of Graves' disease after SARS-CoV-2 infection through an autoimmune pathway. In our opinion, physicians, particularly endocrinologists, must be aware of this condition and keep it in mind as a potential differential diagnosis when encountering a similar clinical scenario.

Genetics, Epigenetics, Cellular Immunology, and Gut Microbiota: Emerging Links With Graves' Disease

Graves’ disease (GD) is a well-known organ-specific autoimmune disease characterized by hyperthyroidism, goiter, and exophthalmos. The incidence of GD is approximately 2.0–3.0% in China and 0.5–2.0% in Western countries. Due to the complex pathogenesis and etiology of GD, current treatment methods have great side effects that seriously endanger human health. Therefore, it is particularly important to understand the pathogenesis of GD. Various studies have shown that genetics, epigenetics, cellular immunology, and gut microbiota are all involved in the development of GD. Genetically, CD25 gene and VDR gene polymorphisms are involved in the development of GD by increasing the ratio of Th17/Treg cells. Epigenetically, miR-23a-3p and lncRNA-MEG3 lead to Th17/Treg imbalance and participate in the progression of GD. Moreover, commensal microbe deletion can disrupt Th17/Treg balance and participate in the occurrence of GD. The imbalance of Th17/Treg cells induced by genetics, epigenetics, and gut microbiota plays a vital role in the pathogenesis of GD. Therefore, this article reviews the role of genetics, epigenetics, cellular immunology, and gut microbiota in the pathogenic mechanism of GD. This may lead to the development of novel therapeutic strategies and providing promising therapeutic targets.

Long COVID a New Derivative in the Chaos of SARS-CoV-2 Infection: The Emergent Pandemic?

Coronavirus disease 2019 (COVID-19) is a multisystem illness caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which can manifest with a multitude of symptoms in the setting of end-organ damage, though it is predominantly respiratory. However, various symptoms may remain after acute SARS-CoV-2 infection, and this condition is referred to as "Long COVID" (LC). Patients with LC may develop multi-organ symptom complex that remains 4-12 weeks after the acute phase of illness, with symptoms intermittently persisting over time. The main symptoms are fatigue, post-exertional malaise, cognitive dysfunction, and limitation of functional capacity. Pediatric patients developed the main symptoms of LC like those described in adults, although there may be variable presentations of LC in children. The underlying mechanisms of LC are not clearly known, although they may involve pathophysiological changes generated by virus persistence, immunological alterations secondary to virus-host interaction, tissue damage of inflammatory origin and hyperactivation of coagulation. Risk factors for developing LC would be female sex, more than five early symptoms, early dyspnea, previous psychiatric disorders, and alterations in immunological, inflammatory and coagulation parameters. There is currently no specific treatment for LC, but it could include pharmacological treatments to treat symptoms, supplements to restore nutritional, metabolic, and gut flora balance, and functional treatments for the most disabling symptoms. In summary, this study aims to show the scientific community the current knowledge of LC.

The Roles of Exosomes in Immunoregulation and Autoimmune Thyroid Diseases

Exosomes are extracellular microvesicles (30-150 nm) released from cells that contain proteins, lipids, RNA and DNA. They can deliver bioactive molecules and serve as carriers facilitating cell-cell communication, such as antigen presentation, inflammatory activation, autoimmune diseases (AIDs) and tumor metastasis. Recently, much attention has been attracted to the biology and functions of exosomes in immune regulation and AIDs, including autoimmune thyroid diseases (AITDs). Some studies have shown that exosomes are involved in the occurrence and development of AITDs, but they are still in the preliminary stage of exploration. This review mainly introduces the association of exosomes with immune regulation and emphasizes the potential role of exosomes in AITDs, aiming to provide new research strategies and directions for the pathogenesis and early diagnosis of AITDs.

SARS-CoV-2: Emerging Role in the Pathogenesis of Various Thyroid Diseases

Coronavirus disease-2019 (COVID-19) is asymptomatic in most cases, but it is impartible and fatal in fragile and elderly people. Heretofore, more than four million people succumbed to COVID-19, while it spreads to every part of the globe. Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) induces various dysfunctions in many vital organs including the thyroid by utilizing ACE2 as a receptor for cellular entry. Emerging reports clearly show the involvement of SARS-CoV-2 in diverse thyroid disorders. Thus, this review article aims to review comprehensively all the recent developments in SARS-CoV-2-induced pathogenesis of thyroid diseases. The review briefly summarizes the recent key findings on the mechanism of SARS-CoV-2 infection, the role of ACE2 receptor in viral entry, SARS-CoV-2-activated molecular signaling in host cells, ACE2 expression in the thyroid, cytokine storm, and its vital role in thyroid dysfunction and long-COVID in relation to thyroid and autoimmunity. Further, it extensively discusses rapidly evolving knowledge on the potential part of SARS-CoV-2 in emerging various thyroid dysfunctions during and post-COVID-19 conditions which include subacute thyroiditis, Graves' diseases, Hashimoto’s thyroiditis, thyrotoxicosis, and other recent advances in further discerning the implications of this virus within thyroid dysfunction. Unraveling the pathophysiology of SARS-CoV-2-triggered thyroid dysfunctions may aid pertinent therapeutic options and management of these patients in both during and post-COVID-19 scenarios.

Simulation Model for Hashimoto Autoimmune Thyroiditis Disease

Hashimoto thyroiditis (HT) is a pathology that often causes a gradual thyroid insufficiency in affected patients due to the autoimmune destruction of this gland. The cellular immune response mediated by T helper lymphocytes TH1 and TH17 can induce the HT disease. In this pathologic condition, there is an imbalance between the TH17 and Treg lymphocytes as well as a gut microbiota dysfunction. The objective of this work was to describe the interactions of the cell subpopulations that participate in HT. To achieve this goal, we generated a mathematical model that allowed the simulation of different scenarios for the dynamic interaction between thyroid cells, the immune system, and the gut microbiota. We used a hypothetical-deductive design of mathematical modeling based on a system of ordinary differential equations, where the state variables are the TH1, TH17, and Treg lymphocytes, the thyrocytes, and the bacteria from gut microbiota. This work generated a compartmental model of the cellular immune response occurring in the thyroid gland. It was observed that TH1 and TH17 lymphocytes could increase the immune cells' activity, as well as activate effector cells directly and trigger the apoptosis and inflammation processes of healthy thyrocytes indirectly. Likewise, the model showed that a reduction in Treg lymphocytes could increase the activity of TH17 lymphocytes when an imbalance of the gut microbiota composition occurred. The numerical results highlight the TH1, TH17, and bacterial balance of the gut microbiota activities as important factors for the development of HT disease.

[T-lymphocytes phenotypic composition of peripheral blood in patients with Graves' disease undergoing conservative therapy with thiamazole]

BACKGROUND

Effective control of autoimmune inflammation in Graves' disease determines necessity to study the T helper (Th) and cytotoxic T-lymphocytes dysfunction, as well as the level of regulatory T-cells (Treg) activation in patients with Graves' disease on thyrostatic medication, which will clarify the immunomodulatory effects of long-term thiamazole treatment serve as targets for more specific therapies.

AIM

To study the phenotypic composition of T-lymphocytes in the peripheral blood of patients with Graves' disease to assess the direction of immune response depending on thimazole-induced euthyroidism duration.

MATERIALS AND METHODS

A single-center, cohort, continuous, open-label, controlled trial was conducted to assess the phenotypic composition of T-lymphocytes in peripheral blood in women with Graves' disease on long-term thiamazole treatment. The phenotypic composition of T-lymphocytes was determined by flow cytometry using direct immunofluorescence with conjugated FITC monoclonal antibodies depending on the duration of thimazole-induced euthyroidism of long-term thiamazole treatment.

RESULTS

The study included 135 women with Graves' disease, mean age 43.09±12.81 years, 120 (88.91%) with a relapse of the disease and 15 (11.09%) with newly diagnosed hyperthyroidism. An increase of activated CD3+CD4+CD25+ was found in patients with Graves' disease with a duration of thimazole-induced euthyroidism 5-8 months and 9-12 months, respectively, Me=0.94 (0.48-1.45), p=0.020) and Me=0.95 (0.41-1.80), p=0.025), in control group - Me=0.12 (0.03-0.68). Compared to the control an increase of CD4+CD25+CD127Low (Treg) was found in patients with a duration of thimazole-induced euthyroidism 5-8 and 9-12 months. The content of Treg in peripheral blood in Graves' disease patients with a duration of thimazole-induced euthyroidism more than 12 months decreases, but remains elevated relative to the control.

CONCLUSION

In patients with Graves' disease with a duration of thimazole-induced euthyroidism 5-8 months and 9-12 months the level of Treg has been increased. The increase of activated Th (CD3+CD4+CD25+) persists independently of thimazole-induced euthyroidism. In patients with Graves' disease with a duration of thimazole-induced euthyroidism for more than 12 months, there is a compensatory increase in regulatory T-lymphocyte, and the total number of T-helpers is restored to the control.

Clinical Observation of Levothyroxine Sodium Combined with Selenium in the Treatment of Patients with Chronic Lymphocytic Thyroiditis and Hypothyroidism and the Effects on Thyroid Function, Mood, and Inflammatory Factors

The purpose of this study was to investigate the therapeutic effects of levothyroxine sodium combined with selenium treatment and single levothyroxine sodium treatment on patients with chronic lymphocytic thyroiditis and hypothyroidism and to analyze the effects of different treatment regimens on patients' thyroid function, mood, and inflammatory factors, with the aim of providing a reference for clinical treatment. The subjects of the current study were 138 chronic lymphocytic thyroiditis (CLT) patients with hypothyroidism admitted to our hospital from May 2016 to September 2019 and were randomly divided into a control group taking levothyroxine sodium (LT4) treatment and a combined group of LT4 combined with selenium treatment, with 69 cases each. Patients in both groups were evaluated for efficacy after 3 months of treatment, and their thyroid function was observed by total triiodothyronine (TT3), total thyroxine (TT4), thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), and thyroid globulin antibody (TGAb), and their mood changes were observed by Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) scores. The levels of inflammatory factors such as interleukin-2 (IL-2), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) were measured, and the occurrence of adverse drug reactions during the treatment period was observed and recorded in all patients. The results showed that the total effective rate of the combined group was significantly higher than that of the control group. The levels of TT3, TT4, TSH, TgAb, and TPOAb, SAS and SDS scores, and levels of inflammatory factors such as IL-2, IL-10, and TNF-α were significantly improved in both groups after treatment. Compared with the control group, TGAb, TPOAb, IL-2, TNF-α levels, and SAS and SDS scores decreased more and IL-10 levels increased more in the combined group, while the differences of other indexes were not statistically significant. This suggests that LT4 has certain efficacy in treating CLT with hypothyroidism, and the combined selenium treatment can improve the therapeutic effect of LT4 and can play a greater role in improving patients' mood and immune and inflammatory responses.

Long COVID or post-COVID-19 syndrome: putative pathophysiology, risk factors, and treatments

Long COVID or post-COVID-19 syndrome first gained widespread recognition among social support groups and later in scientific and medical communities. This illness is poorly understood as it affects COVID-19 survivors at all levels of disease severity, even younger adults, children, and those not hospitalized. While the precise definition of long COVID may be lacking, the most common symptoms reported in many studies are fatigue and dyspnoea that last for months after acute COVID-19. Other persistent symptoms may include cognitive and mental impairments, chest and joint pains, palpitations, myalgia, smell and taste dysfunctions, cough, headache, and gastrointestinal and cardiac issues. Presently, there is limited literature discussing the possible pathophysiology, risk factors, and treatments in long COVID, which the current review aims to address. In brief, long COVID may be driven by long-term tissue damage (e.g. lung, brain, and heart) and pathological inflammation (e.g. from viral persistence, immune dysregulation, and autoimmunity). The associated risk factors may include female sex, more than five early symptoms, early dyspnoea, prior psychiatric disorders, and specific biomarkers (e.g. D-dimer, CRP, and lymphocyte count), although more research is required to substantiate such risk factors. While preliminary evidence suggests that personalized rehabilitation training may help certain long COVID cases, therapeutic drugs repurposed from other similar conditions, such as myalgic encephalomyelitis or chronic fatigue syndrome, postural orthostatic tachycardia syndrome, and mast cell activation syndrome, also hold potential. In sum, this review hopes to provide the current understanding of what is known about long COVID.