Emerging Insights Into the Role of Epigenetics and Gut Microbiome in the Pathogenesis of Graves' Ophthalmopathy

The role of IL-6 in thyroid eye disease: an update on emerging treatments

Elevated serum interleukin-6 (IL-6) levels have been shown to correlate with disease activity in patients with thyroid eye disease (TED), a complex, heterogeneous, autoimmune disease affecting thousands of people worldwide. IL-6 plays a pivotal role in the pathogenesis of TED through three key mechanisms that together may contribute to inflammation, tissue expansion, remodeling, and fibrosis within the orbit. First, IL-6 drives an autoimmune response targeting the thyroid-stimulating hormone receptor (TSHR) by promoting the production of autoantibodies (i.e. TSHR-Ab, TSI), thereby triggering TSHR-dependent immune pathways. Second, IL-6 stimulates the activation and differentiation of orbital fibroblasts, which contributes to the inflammatory process and increase adipogenesis. Finally, IL-6 stimulates T-cell-mediated inflammation, amplifying the immune response within orbital tissues. Although corticosteroids and surgery have served as mainstays of TED treatment, a multimodal approach is often required due to the disease's heterogeneous presentation and response to current treatment options. TED is a chronic, lifelong condition characterized by periods of exacerbation and remission, with inflammation playing a central role in disease progression and severity. Because inflammation can flare intermittently throughout a patient's life, there is growing interest in targeting specific components of the immune system to reduce disease activity and severity. This review focuses on the current evidence supporting IL-6 as a key mediator of TED pathogenesis and explores its potential as a diagnostic biomarker and therapeutic target of the disease.

Endoplasmic reticulum protein TXNDC5 modulates thyroid eye disease TGF-β1-induced myofibroblast transdifferentiation

AIM

There remain limited therapies to treat thyroid eye disease (TED) orbital fibrosis, highlighting the urgency to develop novel targets. Transforming growth factor-β1 (TGF-β1)-induced myofibroblast transdifferentiation from orbital fibroblasts are important pathogenetic factor of TED. Endoplasmic reticulum (ER) stress may play a role in TED pathogenesis since it has been linked to liver, kidney, heart and lung fibrotic remodelling. We would evaluate the role of thioredoxin domain containing 5 (TXNDC5), a fibroblast-enriched ER protein, in TGF-β1-induced myofibroblast transdifferentiation from TED orbital fibroblasts.

METHODS

Orbital fibroblasts from patients with TED were treated with TGF-β1 to investigate ER stress-relative gene expression especially for TXNDC5. To determine if TXNDC5 is involved in TGF-β1-induced fibrosis, we transfected TED orbital fibroblasts by lentivirus with a small hairpin RNA of pLKO-TXNDC5 gene (shTXNDC5) to knockdown TXNDC5 protein expression levels. After transfection of shTXNDC5 in TED orbital fibroblast followed by TGF-β1 treatment, we analysed TGF-β1-induced fibrosis protein expression.

RESULTS

We measured increased TXNDC5 gene and protein expression in primary TED orbital fibroblasts. TXNDC5 protein levels were increased in TED orbital fibroblasts under TGF-β1 stimulation (2.5, 5, 10 and 20 ng/mL). Moreover, TXNDC5 knockdown of attenuated TGFβ1 (5 ng/mL)-induced myofibroblast transdifferentiation and extracellular matrix protein upregulation whereas increasing TXNDC5 expression by a recombinant protein of TXNDC5 (rhTXNDC5) addition increased alpha smooth muscle actin, fibronectin and connective tissue growth factor protein expression.

CONCLUSION

In conclusion, targeting TXNDC5 may be a novel therapeutic approach against TGF-β1-induced myofibroblast transdifferentiation in TED orbital fibroblasts.

Unraveling host regulation of gut microbiota through the epigenome-microbiome axis

Recent studies of dynamic interactions between epigenetic modifications of a host organism and the composition or activity of its associated gut microbiota suggest an opportunity for the host to shape its microbiome through epigenetic alterations that lead to changes in gene expression and noncoding RNA activity. We use insights from microbiota-induced epigenetic changes to review the potential of the host to epigenetically regulate its gut microbiome, from which a bidirectional 'epigenome-microbiome axis' emerges. This axis embeds environmentally induced variation, which may influence the adaptive evolution of host-microbe interactions. We furthermore present our perspective on how the epigenome-microbiome axis can be understood and investigated within a holo-omic framework with potential applications in the applied health and food sciences.

Therapeutic role of histone deacetylase inhibition in an in vitro model of Graves' orbitopathy

Graves' orbitopathy (GO), a manifestation of Graves' disease, is characterized by orbital fibroblast‑induced inflammation, leading to fibrosis or adipogenesis. Histone deacetylase (HDAC) serves a central role in autoimmune diseases and fibrosis. The present study investigated HDAC inhibition in orbital fibroblasts from patients with GO to evaluate its potential as a therapeutic agent. Primary cultured orbital fibroblasts were treated with an HDAC inhibitor, panobinostat, under the stimulation of IL‑1β, TGF‑β or adipogenic medium. Inflammatory cytokines, and fibrosis‑ and adipogenesis‑related proteins were analyzed using western blotting. The effects of panobinostat on HDAC mRNA expression were measured in GO orbital fibroblasts, and specific HDACs were inhibited using small interfering RNA transfection. Panobinostat significantly reduced the IL‑1β‑induced production of inflammatory cytokines and TGF‑β‑induced production of fibrosis‑related proteins. It also suppressed adipocyte differentiation and adipogenic transcription factor production. Furthermore, it significantly attenuated HDAC7 mRNA expression in GO orbital fibroblasts. In addition, the silencing of HDAC7 led to anti‑inflammatory and anti‑fibrotic effects. In conclusion, by inhibiting HDAC7 gene expression, panobinostat may suppress the production of inflammatory cytokines, profibrotic proteins and adipogenesis in GO orbital fibroblasts. The present in vitro study suggested that HDAC7 could be a potential therapeutic target for inhibiting the inflammatory, adipogenic and fibrotic mechanisms of GO.

Gut Microbiota Changes and Its Potential Relations with Thyroid Disorders: From Composition to Therapeutic Targets

Composed of over 1200 species of anaerobes and aerobes bacteria along with bacteriophages, viruses, and fungal species, the human gut microbiota (GM) is vital to health, including digestive equilibrium, immunologic, hormonal, and metabolic homeostasis. Micronutrients, usually refer to trace elements (copper, iodine, iron, selenium, zinc) and vitamins (A, C, D, E), interact with the GM to influence host immune metabolism. So far, microbiome studies have revealed an association between disturbances in the microbiota and various pathological disorders, such as anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, anxiety, depression, early-onset cancers, type 1 diabetes (T1D) and type 2 diabetes (T2D). As common conditions, thyroid diseases, encompassing Graves' disease (GD), Graves' orbitopathy (GO), Hashimoto's thyroiditis (HT), benign nodules, and papillary thyroid cancer (TC), have negative impacts on the health of all populations. Following recent studies, GM might play an integral role in triggering diseases of the thyroid gland. Not only do environmental triggers and genetic predisposing background lead to auto-aggressive damage, involving cellular and humoral networks of the immune system, but the intestinal microbiota interacts with distant organs by signals that may be part of the bacteria themselves or their metabolites. The review aims to describe the current knowledge about the GM in the metabolism of thyroid hormones and the pathogenesis of thyroid diseases and its involvement in the appearance of benign nodules and papillary TC. We further focused on the reciprocal interaction between GM composition and the most used treatment drugs for thyroid disorders. However, the exact etiology has not yet been known. To elucidate more precisely the mechanism for GM involvement in the development of thyroid diseases, future work is needed.

Thyroid Eye Disease: Pilot Study Comparison Between Patients in United States-Based and India-Based Practices

PURPOSE

Thyroid eye disease (TED) phenotype varies by ethnicity/race and genetic/environmental factors. This study compared demographic and clinical characteristics of TED patients from the US and India.

DESIGN

Observational pilot study .

METHODS

Sixty-four patients with TED ages ≥18 years old with active disease (onset of symptoms ≤18 months or presenting clinical activity score (CAS) ≥4) were recruited between March and October 2021 from clinical practices in the United States (Philadelphia, PA) (n = 30) and India (Hyderabad, India) (n = 34). Data collection at baseline and 3 months included clinical measurements, thyroid disease history, and photographs. Ocular symptoms and quality of life data were obtained by phone interview. CAS was calculated using the standard 7-point scale.

RESULTS

There was no statistically significant difference in age, TED duration, or smoking status between patient groups. Both groups had good vision, a low rate of optic neuropathy, and comparable exophthalmometry. US patients were predominantly female (86.7% [26/30]), with a history of hyperthyroidism (96% 29/30). In comparison, Indian patients were 52.9% (18/34, P = .004) female; underlying thyroid disease was distributed between hyperthyroidism (52%), hypothyroidism (17.6%) and euthyroid (9.7%). Mean (SD) CAS in the US cohort was double the score in the India cohort (4.2 (1.7) vs 1.65 (1.7), respectively) (P < .0001). However, patients at both sites experienced subjective symptoms of TED at a similar frequency.

CONCLUSIONS

Observed differences in TED between US and Indian patients warrant further investigation to elucidate differences in pathogenesis, disease expression, or other factors that may influence TED in diverse populations.

A comprehensive epigenetic network can influence the occurrence of thyroid-associated ophthalmopathy by affecting immune and inflammatory response

The primary objective of this study is to understand the regulatory role of epigenetics in thyroid-associated ophthalmopathy (TAO) using multi-omics sequencing data. We utilized tRFs sequencing data, DNA methylation sequencing data, and lncRNA/circRNA/mRNA sequencing data, as well as several RNA methylation target prediction websites, to analyze the regulatory effect of DNA methylation, non-coding RNA, and RNA methylation on TAO-associated genes. Through differential expression analysis, we identified 1019 differentially expressed genes, 985 differentially methylated genes, and 2601 non-coding RNA. Functional analysis showed that differentially expressed genes were mostly associated with the PI3K signaling pathway and the IL17 signaling pathway. Genes regulated by DNA epigenetic regulatory networks were mainly related to the Cytokine-cytokine receptor interaction pathway, whereas genes regulated by RNA epigenetic regulatory networks were primarily related to the T cell receptor signaling pathway. Finally, our integrated regulatory network analysis revealed that epigenetics mainly impacts the occurrence of TAO through its effects on key pathways such as cell killing, cytokine production, and immune response. In summary, this study is the first to reveal a new mechanism underlying the development of TAO and provides new directions for future TAO research.

EZH2 as a major histone methyltransferase in PDGF-BB-activated orbital fibroblast in the pathogenesis of Graves' ophthalmopathy

Graves' ophthalmopathy (GO) is an extra-thyroidal complication of Graves' disease which can lead to vision loss in severe cases. Currently, treatments of GO are not sufficiently effective, so novel therapeutic strategies are needed. As platelet-derived growth factor (PDGF)-BB induces several effector mechanisms in GO orbital fibroblasts including cytokine production and myofibroblast activation, this study aims to investigate the roles of histone lysine methyltransferases (HKMTs) in PDGF-BB-activated GO orbital fibroblasts by screening with HKMTs inhibitors library. From the total of twelve selective HKMT inhibitors in the library, EZH2, G9a and DOT1L inhibitors, DZNeP, BIX01294 and Pinometostat, respectively, prevented PDGF-BB-induced proliferation and hyaluronan production by GO orbital fibroblasts. However, only EZH2 inhibitor, DZNeP, significantly blocked pro-inflammatory cytokine production. For the HKMTs expression in GO orbital fibroblasts, PDGF-BB significantly and time-dependently induced EZH2, G9a and DOT1L mRNA expression. To confirm the role of EZH2 in PDGF-BB-induced orbital fibroblast activation, EZH2 silencing experiments revealed suppression of PDGF-BB-induced collagen type I and α-SMA expression along with decreasing histone H3 lysine 27 trimethylation (H3K27me3) level. In a more clinically relevant model than orbital fibroblast culture experiments, DZNeP treated GO orbital tissues significantly reduced pro-inflammatory cytokine production while slightly reduced ACTA2 mRNA expression. Our data is the first to demonstrate that among all HKMTs EZH2 dominantly involved in the expression of myofibroblast markers in PDGF-BB-activated orbital fibroblast from GO presumably via H3K27me3. Thus, EZH2 may represent a novel therapeutics target for GO.

Identification of potential immunotherapeutic targets and prognostic biomarkers in Graves' disease using weighted gene co-expression network analysis

Graves' disease (GD) is an autoimmune disorder characterized by hyperthyroidism resulting from autoantibody-induced stimulation of the thyroid gland. Despite recent advancements in understanding GD's pathogenesis, the molecular processes driving disease progression and treatment response remain poorly understood. In this study, we aimed to identify crucial immunogenic factors associated with GD prognosis and immunotherapeutic response. To achieve this, we implemented a comprehensive screening strategy that combined computational immunogenicity-potential scoring with multi-parametric cluster analysis to assess the immunomodulatory genes in GD-related subtypes involving stromal and immune cells. Utilizing weighted gene co-expression network analysis (WGCNA), we identified co-expressed gene modules linked to cellular senescence and immune infiltration in CD4+ and CD8+ GD samples. Additionally, gene set enrichment analysis enabled the identification of hallmark pathways distinguishing high- and low-immune subtypes. Our WGCNA analysis revealed 21 gene co-expression modules comprising 1,541 genes associated with immune infiltration components in various stages of GD, including T cells, M1 and M2 macrophages, NK cells, and Tregs. These genes primarily participated in T cell proliferation through purinergic signaling pathways, particularly neuroactive ligand-receptor interactions, and DNA binding transcription factor activity. Three genes, namely PRSS1, HCRTR1, and P2RY4, exhibited robustness in GD patients across multiple stages and were involved in immune cell infiltration during the late stage of GD (p < 0.05). Importantly, HCRTR1 and P2RY4 emerged as potential prognostic signatures for predicting overall survival in high-immunocore GD patients (p < 0.05). Overall, our study provides novel insights into the molecular mechanisms driving GD progression and highlights potential key immunogens for further investigation. These findings underscore the significance of immune infiltration-related cellular senescence in GD therapy and present promising targets for the development of new immunotherapeutic strategies.

The connection between epigenetics and gut microbiota-current perspective

Both the epigenetic changes and gut microbiota (GM) have attracted a growing interest in establishing effective diagnostics and potential therapeutic strategies for a number of diseases. These disorders include metabolic, central nervous system-related diseases, autoimmune, and gastrointestinal infections (GI). Despite the number of studies, there is no extensive review that connects the epigenetics modifications and GM as biomarkers that could confer effective diagnostics and confer treatment options. To this end, this review hopes to give detailed information on connecting the modifications in epigenetic and GM. An updated and detailed information on the connection between the epigenetics factors and GM that influence diseases are given. In addition, the review showed some associations between the epigenetics to the maternal GM and offspring health. Finally, the limitations of the concept and prospects into this new emerging discipline were also looked into. Although this review elucidated on the maternal diet and response to offspring health with respect to GM and epigenetic modifications, there still exist various limitations to this newly emerging discipline. In addition to integrating complementary multi-omics data, longitudinal sampling will aid with the identification of functional mechanisms that may serve as therapeutic targets. To this end, this review gave a detailed perspective into harnessing disease diagnostics, prevention and treatment options through epigenetics and GM.

Understanding the clinical and molecular basis of thyroid orbitopathy: a review of recent evidence

Thyroid eye disease (TED) is an autoimmune orbital inflammatory disease which ranges from mild to severe. Tissue remodeling, fibrosis and fat proliferation cause changes in the orbital tissues which can affect esthetics and visual function. In its severe form, it is sight threatening, debilitating, and disfiguring and may lead to social stigma, the embarrassment about which has an impact on the quality of life of those affected and the family members. The pathogenesis of TED, which is influenced by genetic, immunological, and environmental factors, is complex and not fully elucidated. However, it remains unknown what factors determine the severity of the disease. Recent research has revealed a number of diagnostic and prognostic biomarkers of this disease. In this overview of TED, we focus on new insights and perspectives regarding biological agents that may provide a basis for new treatment modalities.

The relationship between thyroid and human-associated microbiota: A systematic review of reviews

In recent years, a growing number of studies have examined the relationship between thyroid pathophysiology and intestinal microbiota composition. The reciprocal influence between these two entities has been proven so extensive that some authors coined the term "gut-thyroid axis". However, since some papers reported conflicting results, several aspects of this correlation need to be clarified. This systematic review was conceived to achieve more robust information about: 1)the characteristics of gut microbiota composition in patients with the more common morphological, functional and autoimmune disorders of the thyroid; 2)the influence of gut microbial composition on micronutrients that are essential for the maintenance of thyroid homeostasis; 3)the effect of probiotics, prebiotics and synbiotics, some of the most popular over-the-counter products, on thyroid balance; 4)the opportunity to use specific dietary advice. The literature evaluation was made by three authors independently. A five steps strategy was a priori adopted. After duplicates removal, 1106 records were initially found and 38 reviews were finally included in the analysis. The systematic reviews of reviews found that: 1) some significant variations characterize the gut microbiota composition in patients with thyroid disorders. However, geographical clustering of most of the studies prevents drawing definitive conclusions on this topic; 2) the available knowledge about the effect of probiotics and synbiotics are not strong enough to suggest the routine use of these compounds in patients with thyroid disorders; 3) specific elimination nutrition should not be routine suggested to patients, which, instead have to be checked for possible micronutrients and vitamins deficiency, often owed to gastrointestinal autoimmune comorbidities.

Gut microbiota and thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is a multifactorial-mediated autoimmune orbital disease with the highest incidence of orbital disease in adults. Due to the complex clinical manifestations and prolonged course,TAO seriously affect the physical and mental health of patients.The pathogenesis of TAO has not been fully elucidated and the treatment lacks specificity. Therefore, in-depth research on the pathogenesis of TAO is to find effective treatments. In recent years, studies have suggested that there is gut microbiota disorder in TAO, and the risk factors of TAO can promote gut microbiota disorder. Disordered gut microbiota can participate in the occurrence and development of TAO via influencing T cell differentiation, mimicking autoantigens, and influencing host non-coding RNA expression. Modulating the gut microbiota also has therapeutic effects on TAO and is a promising therapeutic approach.

Machine learning-based prediction of diagnostic markers for Graves' orbitopathy

PURPOSE

The pathogenesis of Graves' orbitopathy/thyroid-associated orbitopathy (TAO) is still unclear, and abnormal DNA methylation in TAO has been reported. Thus, selecting and exploring TAO biomarkers associated with DNA methylation may provide a reference for new therapeutic targets.

METHODS

The TAO-associated expression data and methylation data were downloaded from The Gene Expression Omnibus database. Firstly, weighted gene co-expression network analysis was used to obtain the TAO-related genes, which were intersected with differentially methylated genes (DMGs), and differentially expressed genes between TAO samples and normal samples to obtain TAO-associated DMGs (TA-DMGs). Thereafter, the functions of the TA-DMGs were analyzed, and diagnostic markers were screened by least absolute shrinkage and selection operator (Lasso) regression analysis and support vector machine (SVM) analysis. The expression levels and diagnostic values of the diagnostic markers were also analyzed. Furthermore, single gene pathway enrichment analysis was performed for each diagnostic marker separately using gene set enrichment analysis (GSEA) software. Next, we also performed immune infiltration analysis for each sample in the GSE58331 dataset using the single-sample GSEA algorithm, and the correlation between diagnostic markers and differential immune cells was explored. Lastly, the expressions of diagnostic markers were explored by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

A total of 125 TA-DMGs were obtained. The enrichment analysis results indicated that these TA-DMGs were mainly involved in immune-related pathways, such as Th1 and Th2 cell differentiation and the regulation of innate immune response. Moreover, two diagnostic markers, including S100A11 and NKD2, were obtained by Lasso regression analysis and SVM analysis. Single gene pathway enrichment analysis showed that S100A11 was involved in protein polyufmylation, pancreatic-mediated proteolysis, and NKD2 was involved in innate immune response in mucosa, Wnt signaling pathway, etc. Meanwhile, immune cell infiltration analysis screened 12 immune cells, including CD56 dim natural killer cells and Neutrophil cells that significantly differed between TAO and normal samples, with the strongest positive correlation between NKD2 and CD56 dim natural killer cells. Finally, the qRT-PCR illustrated the expressions of NKD2 and S100A11 between normal and TAO.

CONCLUSION

NKD2 and S100A11 were screened as biomarkers of TAO and might be regulated by DNA methylation in TAO, providing a new reference for the diagnosis and treatment of TAO patients.

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.

New Onset or Deterioration of Thyroid Eye Disease After mRNA SARS-CoV-2 Vaccines: Report of 2 Cases and Literature Review

CONTEXT

Occurrence of Graves' disease (GD) has been reported following SARS-CoV-2 vaccine administration, but little is known about thyroid eye disease (TED) after SARS-CoV-2 vaccination.

OBJECTIVE

We describe 2 cases of TED activation following mRNA SARS-CoV-2 vaccination and review additional cases reported in the literature.

METHODS

We report 2 cases of TED activation following SARS-CoV-2 vaccination: 1 case of TED worsening in a patient with GD, and 1 of de novo active TED progressing to dysthyroid optic neuropathy in a patient with a history of Hashimoto hypothyroidism. Our literature search revealed 8 additional reported TED cases associated with SARS-CoV-2 vaccination until June 2022. We review the characteristics, duration, and management of TED following SARS-CoV-2 vaccination in these cases.

RESULTS

Of all 10 reported TED cases following SARS-CoV-2 vaccination, 4 developed new-onset TED and 6 previously stable TED cases experienced significant deterioration. Six patients had known GD and 2 patients had Hashimoto thyroiditis. Two cases progressed to dysthyroid optic neuropathy, 6 had moderate/severe active disease, and 2 had mild disease that did not require treatment. Seven TED cases received teprotumumab and had a favorable response, 2 of whom had prior limited response to initial prednisone or methylprednisolone and tocilizumab therapy.

CONCLUSION

New diagnosis or deterioration of TED after mRNA SARS-CoV-2 vaccination can occur, with most cases described in patients with underlying autoimmune thyroid disease. Our report raises awareness to this potential complication to promote early recognition and prompt management of TED associated with mRNA SARS-CoV-2 vaccines. Further studies are needed to explore the mechanism, risk factors, prevention, and treatment of TED following mRNA SARS-CoV-2 vaccination.

DNA Methylation in Autoimmune Thyroid Disease

Graves disease and Hashimoto disease form part of the spectrum of autoimmune thyroid disease (AITD), to which genetic and environmental factors are recognized contributors. Epigenetics provides a potential link between environmental influences, gene expression, and thyroid autoimmunity. DNA methylation (DNAm) is the best studied epigenetic process, and global hypomethylation of leukocyte DNA is reported in several autoimmune disorders. This review summarizes the current understanding of DNAm in AITD. Targeted DNAm studies of blood samples from AITD patients have reported differential DNAm in the promoter regions of several genes implicated in AITD, including TNF, IFNG, IL2RA, IL6, ICAM1, and PTPN22. In many cases, however, the findings await replication and are unsupported by functional studies to support causal roles in AITD pathogenesis. Furthermore, thyroid hormones affect DNAm, and in many studies confounding by reverse causation has not been considered. Recent studies have shown that DNAm patterns in candidate genes including ITGA6, PRKAA2, and DAPK1 differ between AITD patients from regions with different iodine status, providing a potential mechanism for associations between iodine and AITD. Research focus in the field is moving from candidate gene studies to an epigenome-wide approach. Genome-wide methylation studies of AITD patients have demonstrated multiple differentially methylated positions, including some in immunoregulatory genes such as NOTCH1, HLA-DRB1, TNF, and ICAM1. Large, epigenome-wide studies are required to elucidate the pathophysiological role of DNAm in AITD, with the potential to provide novel diagnostic and prognostic biomarkers as well as therapeutic targets.

Looking Beyond Th17 Cells: A Role for Th17.1 Cells in Thyroid-associated Ophthalmopathy?

Thyroid-associated ophthalmopathy (TAO), an ordinary extrathyroid syndrome of Graves' disease (GD), is closely associated with immunity. T helper (Th) 17, Th1, and Th2 cells in Th lineages are thought to be related to the disease pathogenesis. Recently, there has been growing evidence that Th17.1 cells are involved in the development and progression of TAO. The characteristics of this pathology are similar to those of Th1 and Th17 lymphocytes, which secrete interferon (IFN)-γ and interleukin (IL)-17A. This paper reviews the potential role of the Th17.1 subgroup pathogenesis of TAO. The therapeutic effects of drugs that can modulate Th17.1 cell populations are also highlighted. Rich Th17.1 cells exist in peripheral blood and ocular tissues of patients suffering from thyroid eye disease (TED), especially those with severe or steroid-resistant TAO. The bias of Th17.1 cells to secrete cytokines partly determines the pathological outcome of TAO patients. Th17.1 cells are important in regulating fibrosis, adipocyte differentiation, and hyaluronic acid production. In summary, the Th17.1 subpopulation is essential in the onset and progression of TED, and targeting Th17.1 cell therapy may be a promising therapeutic approach.

A cause-effect relationship between Graves' disease and the gut microbiome contributes to the thyroid-gut axis: A bidirectional two-sample Mendelian randomization study

Background

An association between Graves' disease (GD) and the gut microbiome has been identified, but the causal effect between them remains unclear.

Methods

Bidirectional two-sample Mendelian randomization (MR) analysis was used to detect the causal effect between GD and the gut microbiome. Gut microbiome data were derived from samples from a range of different ethnicities (18,340 samples) and data on GD were obtained from samples of Asian ethnicity (212,453 samples). Single nucleotide polymorphisms (SNPs) were selected as instrumental variables according to different criteria. They were used to evaluate the causal effect between exposures and outcomes through inverse-variance weighting (IVW), weighted median, weighted mode, MR-Egger, and simple mode methods. F-statistics and sensitivity analyses were performed to evaluate bias and reliability.

Results

In total, 1,560 instrumental variables were extracted from the gut microbiome data (p< 1 × 10⁵). The classes Deltaproteobacteria [odds ratio (OR) = 3.603] and Mollicutes, as well as the genera Ruminococcus torques group, Oxalobacter, and Ruminococcaceae UCG 011 were identified as risk factors for GD. The family Peptococcaceae and the genus Anaerostipes (OR = 0.489) were protective factors for GD. In addition, 13 instrumental variables were extracted from GD (p< 1 × 10^-8), causing one family and eight genera to be regulated. The genus Clostridium innocuum group (p = 0.024, OR = 0.918) and Anaerofilum (p = 0.049, OR = 1.584) had the greatest probability of being regulated. Significant bias, heterogeneity, and horizontal pleiotropy were not detected.

Conclusion

A causal effect relationship exists between GD and the gut microbiome, demonstrating regulatory activity and interactions, and thus providing evidence supporting the involvement of a thyroid-gut axis.

Graves' disease and inflammatory bowel disease: A bidirectional Mendelian randomization

CONTEXT

Both Graves' disease (GD) and inflammatory bowel disease (IBD) are common autoimmune diseases that severely damage patients' quality of life. Previous epidemiological studies have suggested associations between GD and IBD. However, whether a causal relationship exists between these two diseases remains unknown.

OBJECTIVE

To infer a causal relationship between GD and IBD using bidirectional two-sample Mendelian randomization(MR).

METHODS

We performed bidirectional two-sample MR to infer a causal relationship between GD and IBD using GWAS summary data obtained from Biobank Japan (BBJ) and the International Inflammatory Bowel Disease Genetic Consortium (IIBDGC). Several methods (random-effect inverse variance weighted, weighted median, MR‒Egger regression, and MR-PRESSO) were used to ensure the robustness of the causal effect. Heterogeneity was measured based on Cochran's Q value. Horizontal pleiotropy was evaluated by MR‒Egger regression and leave-one-out analysis.

RESULTS

Genetically predicted IBD may increase the risk of GD by 24% (OR 1.24, 95% CI 1.01-1.52, p = 0.041). Crohn's disease (CD) may increase the risk of GD, whereas ulcerative colitis (UC) may prevent patients from developing GD. Conversely, genetically predicted GD may slightly increase the risk of CD, although evidence indicating that the presence of GD increased the risk of UC or IBD was lacking. Outlier-corrected results were consistent with raw causal estimates.

CONCLUSIONS

Our study revealed a potentially higher comorbidity rate for GD and CD. However, UC might represent a protective factor for GD. The underlying mechanism and potential common pathways await discovery.

Insights into the role of DNA methylation and gene expression in Graves' orbitopathy

CONTEXT

A role of DNA methylation in Graves' orbitopathy (GO) has been proposed. Design. To investigate DNA methylation and gene expression in orbital fibroblasts from control and GO patients, under basal conditions or following challenge with an anti-TSH receptor antibody (M22) or cytokines involved in GO; to investigate the relationship between DNA methylation and cell function (proliferation); to perform a methylome analysis. Setting. Referral Center. Materials. Orbital fibroblasts from six GO and six control patients. Intervention. None. Main Outcome Measure. Methylome analysis of the whole genome. Results. Global DNA methylation increased significantly both in control and GO fibroblasts upon incubation with M22. Expression of two selected genes (CYP19A1 and AIFM2) was variably affected by M22 and interleukin-6. M22 increased cell proliferation in control and GO fibroblasts, which correlated with global DNA methylation. Methylome analysis revealed 19,869 DNA regions differently methylated in GO fibroblasts, encompassing 3,957 genes and involving CpG islands, shores and shelves. One-hundred and nineteen gene families and subfamilies, 89 protein groups, 402 biological processes and seven pathways were involved. Three genes found to be differentially expressed were concordantly hyper- or hypomethylated. Among the differently methylated genes, insulin-like growth factor-1 receptor and several fibroblast growth factors and receptors were included.

CONCLUSIONS

We propose that, when exposed to an autoimmune environment, orbital fibroblasts undergo hyper- or hypomethylation of certain genes, involving CpG promoters, which results in differential gene expression, which may be responsible for functional alterations, in particular higher proliferation, and ultimately for the GO phenotype in vivo.

Current concepts regarding Graves' orbitopathy

Graves' orbitopathy (GO) is an orbital autoimmune disorder and the main extrathyroidal manifestation of Graves' disease, the most common cause of hyperthyroidism. GO affects about 30% of Graves' patients, although fewer than 10% have severe forms requiring immunosuppressive treatments. Management of GO requires a multidisciplinary approach. Medical therapies for active moderate-to-severe forms of GO (traditionally, high-dose glucocorticoids) often provide unsatisfactory results, and subsequently surgeries are often needed to cure residual manifestations. The aim of this review is to provide an updated overview of current concepts regarding the epidemiology, pathogenesis, assessment, and treatment of GO, and to present emerging targeted therapies and therapeutic perspectives. Original articles, clinical trials, systematic reviews, and meta-analyses from 1980 to 2021 were searched using the following terms: Graves' disease, Graves' orbitopathy, thyroid eye disease, glucocorticoids, orbital radiotherapy, rituximab, cyclosporine, azathioprine, teprotumumab, TSH-receptor antibody, smoking, hyperthyroidism, hypothyroidism, thyroidectomy, radioactive iodine, and antithyroid drugs. Recent studies suggest a secular trend toward a milder phenotype of GO. Standardized assessment at a thyroid eye clinic allows for a better general management plan. Treatment of active moderate-to-severe forms of GO still relies in most cases on high-dose systemic-mainly intravenous-glucocorticoids as monotherapy or in combination with other therapies-such as mycophenolate, cyclosporine, azathioprine, or orbital radiotherapy-but novel biological agents-including teprotumumab, rituximab, and tocilizumab-have achieved encouraging results.

Potential Therapeutic Activity of Berberine in Thyroid-Associated Ophthalmopathy: Inhibitory Effects on Tissue Remodeling in Orbital Fibroblasts

Purpose

Berberine (BBR), an alkaloid produced by a traditional Chinese plant, was recently attributed multiple effects on lipometabolism, inflammation, and fibrosis. Thyroid-associated ophthalmopathy (TAO) is highly associated with these pathologic changes. Thus, we aimed to examine the potential therapeutic effect of BBR in an in vitro model of TAO.

Methods

Orbital fibroblasts (OFs) obtained from control donors (n = 6) or patients with TAO (n = 6) were cultured. The CCK-8 assay was conducted for assessing the optimal concentration range. Oil Red O staining, Western blotting, and quantitative RT-PCR (qRT-PCR) were conducted to assess adipogenesis in OFs. RNA sequencing (RNA-seq) was used to screen the key pathways of the antiadipogenic effect mediated by BBR. Along with incremental concentrations of BBR, IL-1β–induced expression of proinflammatory molecules was determined by ELISA and qRT-PCR. In addition, TGF-β–induced hyaluronan (HA) production and fibrosis were evaluated by ELISA, qRT-PCR, and Western blotting.

Results

TAO-OFs, but not control fibroblasts (CON-OFs), were readily differentiated into adipocytes with the commercial medium. Intracellular lipid accumulation was dose-dependently decreased by BBR, and adipogenic markers were also downregulated. Moreover, the PPARγ and AMPK pathways were screened out by RNA-seq and their downstream effectors were suppressed by BBR. Besides, BBR attenuated IL-1β–induced expression of proinflammatory molecules in both TAO-OFs and CON-OFs by blocking nuclear factor–κB signaling. BBR's inhibitory effect on TGF-β–mediated tissue remodeling was also confirmed in OFs.

Conclusions

These findings demonstrate BBR has outstanding capabilities of controlling adipogenesis, inflammation, HA production, and fibrosis in OFs, highlighting its potential therapeutic role in TAO management.

Research progress on the pathogenesis of Graves’ ophthalmopathy: Based on immunity, noncoding RNA and exosomes

Graves’ ophthalmopathy (GO), also known as thyroid-associated ophthalmopathy, is a common potentially vision-threatening organ-specific autoimmune disease and the most common extrathyroidal manifestation of Graves’ disease. It can happen to those who have hyperthyroidism or euthyroidism. At present, the pathogenesis of GO has not been fully elucidated, and the majority of clinical treatments are symptomatic. Therefore, we are eager to discover any new therapeutic strategies that target the etiology of GO. To provide fresh ideas for the creation of new therapeutic techniques, this study primarily discusses the research state and progress of GO-related pathogenesis from the perspectives of GO’s cellular immunity, autoantigens, non-coding RNAs, and exosomes.