Regulation of Orbital Fibrosis and Adipogenesis by Pathogenic Th17 Cells in Graves Orbitopathy

Single-cell multiomic analysis unveils the immune landscape dynamics of graves' ophthalmopathy

Graves' ophthalmopathy (GO) is an autoimmune disease that occurs concurrently with Graves' disease, potentially leading to facial disfigurement and irreversible vision loss. However, the molecular characteristics of cellular changes in the peripheral immune environment of GO patients remain unclear. This study presents a multi-omics single-cell analysis of peripheral blood from GO patients and healthy controls, revealing key molecular alterations in immune cell subpopulations. We identify increased chromatin accessibility and regulatory activity of pro-inflammatory factors, such as FOS and NF-κB family. Immune repertoire analysis shows enhanced diversity in GO patients. Notably, GO-specific clonal expansions are enriched in CD8 effector T (CD8 Te) cells, which exhibit signs of enhanced T cell chemotaxis and exhaustion. Multi-omics integration analysis reveals that changes in SLC35G1 and IDNK expression in CD8 Te are linked to disease phenotypes, with trends aligning with experimental results. We find that this cell cluster could infiltrate into orbital tissues and upregulate fibrosis-related pathways associated with fibroblasts in GO. These findings indicate its potential role in driving disease progression. Our study reveals the epigenetic and transcriptomic landscape in the peripheral blood of GO patients, enhancing the understanding of the pathogenic molecular mechanisms and offering potential directions for prevention and treatment.

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.

Targeted immunotherapies for Graves' thyroidal & orbital diseases

Background

Graves' hyperthyroidism and its associated Graves' orbitopathy are common autoimmune disorders associated with significant adverse health impact. Current standard treatments have limitations regarding efficacy and safety, and most do not specifically target the pathogenic mechanisms. We aim to review the latest development of targeted immunotherapies in these two closely related disorders.

Summary

Targeted immunotherapies of Graves' hyperthyroidism have recently demonstrated clinical efficacy in early phase clinical studies. They include rituximab, an anti-CD20 monoclonal antibody which causes rapid B cell depletion; ATX-GD-59, an antigen specific immunotherapy which restores immune tolerance to thyrotropin receptor; iscalimab, an anti-CD40 monoclonal antibody which blocks the CD40-CD154 co-stimulatory pathway in B-T cell interaction; and K1-70, a thyrotropin receptor blocking monoclonal antibody. Furthermore, there have been major therapeutic advances in the management of Graves' orbitopathy. Mycophenolate has a dual mechanism of action both inhibiting the proliferation of activated B & T cells as well as the mammalian target of rapamycin growth intracellular pathway. Rituximab appears to be effective in active disease of recent onset without impending dysthyroid optic neuropathy. Both tocilizumab (anti-interleukin 6 receptor monoclonal antibody) and sirolimus (mammalian target of rapamycin inhibitor) showed promise in glucocorticoid resistant active disease. Teprotumumab, an anti-insulin-like growth factor-1 receptor monoclonal antibody, demonstrated remarkable all-round efficacy across a wide disease spectrum. Linsitinib, a dual small molecule inhibitor of insulin-like growth factor-1 receptor and insulin receptor, displayed significant proptosis reduction in its phase 2b/3 study. Finally, Batoclimab, an anti-neonatal fragment crystallizable receptor monoclonal antibody, which blocks recycling of pathogenic thyrotropin receptor antibody, showed promising signals for significant proptosis reduction, disease inactivation, overall response, and improvement of quality of life.

Conclusion

Therapeutic advances will continue to optimize our management of Graves' hyperthyroidism and its associated orbitopathy in an effective and safe manner.

Novel perspectives on the pharmacological treatment of thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO), an autoimmune disease closely related to thyroid dysfunction, remains a challenging ophthalmic condition among adults. Its clinical manifestations are complex and diverse, and disease progression can lead to exophthalmos, diplopia, exposure keratitis, corneal ulceration, and compressive optic neuropathy, resulting in irreversible vision damage or even blindness. Traditional treatment methods for TAO, including glucocorticoids, immunosuppressants, and radiation therapy, often have limitations and side effects, making this disease problematic in ophthalmology. As a result, the development of novel targeted drugs has become a research hotspot for addressing the pathogenesis of TAO. A range of novel targeted drugs, such as teprotumumab and tocilizumab, have been successfully developed and demonstrated remarkable efficacy in relieving inflammation and managing this disease. In addition, some drug candidates and molecular targets identified in the TAO in vitro model have shown promising prospects. This article briefly reviews the potential new strategies for future clinical treatment and the progress of new drug therapies for TAO.

Ocular immune-related diseases: molecular mechanisms and therapy

Ocular immune-related diseases, represent a spectrum of conditions driven by immune system dysregulation, include but not limit to uveitis, diabetic retinopathy, age-related macular degeneration, Graves' ophthalmopathy, etc. The molecular and cellular mechanisms underlying these diseases are typically dysfunctioned immune responses targeting ocular tissues, resulting in inflammation and tissue damage. Recent advances have further elucidated the pivotal role of different immune responses in the development, progression, as well as management of various ocular immune diseases. However, there is currently a relative lack of connection between the cellular mechanisms and treatments of several immune-related ocular diseases. In this review, we discuss recent findings related to the immunopathogenesis of above-mentioned diseases. In particular, we summarize the different types of immune cells, inflammatory mediators, and associated signaling pathways that are involved in the pathophysiology of above-mentioned ophthalmopathies. Furthermore, we also discuss the future directions of utilizing anti-inflammatory regime in the management of these diseases. This will facilitate a better understanding of the pathogenesis of immune-related ocular diseases and provide new insights for future treatment approaches.

Dynamic transition of Tregs to cytotoxic phenotype amid systemic inflammation in Graves' ophthalmopathy

Graves' disease (GD) is an autoimmune condition that can progress to Graves' ophthalmopathy (GO), leading to irreversible damage to orbital tissues and potential blindness. The pathogenic mechanism is not fully understood. In this study, we conducted single-cell multi-omics analyses on healthy individuals, patients with GD without GO, newly diagnosed patients with GO, and treated patients with GO. Our findings revealed gradual systemic inflammation during GO progression, marked by overactivation of cytotoxic effector T cell subsets, and expansion of specific T cell receptor clones. Importantly, we observed a decline in the immunosuppressive function of activated Treg (aTreg) accompanied by a cytotoxic phenotypic transition. In vitro experiments revealed that dysfunction and transition of GO-autoreactive Treg were regulated by the yin yang 1 (YY1) upon secondary stimulation of thyroid stimulating hormone receptor (TSHR) under inflammatory conditions. Furthermore, adoptive transfer experiments of the GO mouse model confirmed infiltration of these cytotoxic Treg into the orbital lesion tissues. Notably, these cells were found to upregulate inflammation and promote pathogenic fibrosis of orbital fibroblasts (OFs). Our results reveal the dynamic changes in immune landscape during GO progression and provide direct insights into the instability and phenotypic transition of Treg, offering potential targets for therapeutic intervention and prevention of autoimmune diseases.

IL-22, a vital cytokine in autoimmune diseases

Interleukin-22 (IL-22) is a vital cytokine that is dysregulated in various autoimmune conditions including rheumatoid arthritis (RA), multiple sclerosis (MS), and Alzheimer's disease (AD). As the starting point for the activation of numerous signaling pathways, IL-22 plays an important role in the initiation and development of autoimmune diseases. Specifically, imbalances in IL-22 signaling can interfere with other signaling pathways, causing cross-regulation of target genes which ultimately leads to the development of immune disorders. This review delineates the various connections between the IL-22 signaling pathway and autoimmune disease, focusing on the latest understanding of the cellular sources of IL-22 and its effects on various cell types. We further explore progress with pharmacological interventions related to targeting IL-22, describing how such therapeutic strategies promise to usher in a new era in the treatment of autoimmune disease.

Graves disease: latest understanding of pathogenesis and treatment options

Graves disease is the most common cause of hyperthyroidism in iodine-sufficient areas. The main responsible mechanism is related to autoantibodies that bind and activate the thyrotropin receptor (TSHR). Although Graves hyperthyroidism is relatively common, no causal treatment options are available. Established treatment modalities are antithyroid drugs, which reduce thyroid hormone synthesis, radioactive iodine and surgery. However, emerging drugs that target the main autoantigen (monoclonal antibodies, small molecules, peptides) or block the immune pathway have been recently tested in clinical trials. Graves disease can involve the thyroid exclusively or it can be associated with extrathyroidal manifestations, among which Graves orbitopathy is the most common. The presence of Graves orbitopathy can change the management of the disease. An established treatment for moderate-to-severe Graves orbitopathy is intravenous glucocorticoids. However, recent advances in understanding the pathogenesis of Graves orbitopathy have allowed the development of new target-based therapies by blocking pro-inflammatory cytokine receptors, lymphocytic infiltration or the insulin-like growth factor 1 receptor (IGF1R), with several clinical trials providing promising results. This article reviews the new discoveries in the pathogenesis of Graves hyperthyroidism and Graves orbitopathy that offer several important tools in disease management.

A Comprehensive Review of Thyroid Eye Disease Pathogenesis: From Immune Dysregulations to Novel Diagnostic and Therapeutic Approaches

Thyroid eye disease is a complex inflammatory disorder of the orbit that has gained tremendous interest over the past years, and numerous scientific efforts have been deployed to elucidate its pathophysiology for novel drug development. Our manuscript will delve into the molecular dysregulations involved in the pathogenesis of thyroid eye disease that led to its clinical manifestations. Abnormalities within the apoptotic pathway, inflammatory cascade, and autoimmune regulatory systems will be covered. We will further discuss the challenges involved in its diagnosis and management and provide a summary of the current diagnostic tools (i.e., molecular biomarkers, diagnostic scores) from the perspective of clinicians. Finally, our comprehensive literature review will provide a thorough summary of most recent preclinical and clinical studies around the topic of thyroid eye disease, with an emphasis on the manuscripts published within the last five years. We believe our manuscript will bring novelty within the field by bridging the fundamental sciences with the clinical aspect of this disease. This review will be a great tool for clinicians in better understanding the pathogenesis of thyroid eye disease while providing an outlook on future perspectives (i.e., liquid biopsies, artificial intelligence).

A combined transcriptomics and proteomics approach reveals S100A4 as a potential biomarker for Graves' orbitopathy

Background

There are no reliable biomarkers to identify Graves' disease patients who will develop severe Graves' orbitopathy (GO). We hypothesize that integrating various omics platforms can enhance our understanding of disease mechanisms and uncover potential biomarkers. This study aimed to (1) elucidate the differential gene expression profile of orbital fibroblasts in GO during early adipogenesis to better understand disease mechanisms and (2) compare tear protein profiles from our earlier study and the transcriptome profiles of orbital fibroblasts (OFs) to identify possible biomarkers of the disease.

Methods

OFs were grown from orbital adipose tissue obtained from nine GO patients (three for discovery and six for validation experiments). Total RNA was extracted from OFs on day 0 as the baseline for each sample and from differentiated OFs on days 4 and 8. Protein-protein interaction (PPI) analysis and functional enrichment analysis were also carried out. The differentially expressed genes (DEGs) from the RNA sequencing experiments were then compared to the full tear proteome profile from the author's previous study, which examined the tear protein changes of GO patients based on fold change > 1.6 or < -1.6. FDR < 0.05 was applied within all datasets. Further validation of S100 calcium-binding protein A4 (S100A4) downregulation in GO was performed via quantitative real-time PCR (qPCR).

Results

The whole transcriptomic analysis revealed 9 upregulated genes and 15 downregulated genes in common between the discovery and validation experiments. From the PPI network analysis, an interaction network containing six identified DEGs (ALDH2, MAP2K6, MT2A, SOCS3, S100A4, and THBD) was observed. The functional enrichment network analysis identified a set of genes related to oxysterol production. S100A4 was found to be consistently downregulated in both our transcriptome studies and the full-tear proteome profile from the author's previous study.

Conclusion

Our study identified several DEGs and potential gene pathways in GO patients, which concurred with the results of other studies. Tear S100A4 may serve as a biomarker for the propensity to develop thyroid eye disease (TED) in patients with autoimmune thyroid disease (AITD) before clinical manifestation and should be confirmed in future studies.

IL-17 and IL-38 gene polymorphisms in thyroid-associated ophthalmopathy

BACKGROUND

Thyroid-associated ophthalmopathy (TAO) is an autoimmune condition commonly linked with Graves' disease (GD), characterized by orbital tissue inflammation and fibrosis. It is hypothesized that gene polymorphisms may influence production of the IL-17 and IL-38 cytokines, thereby impacting TAO development and progression. This study focused on investigating the gene polymorphisms of IL-17 (rs9463772 C/T in IL17F) and IL-38 (rs3811058 C/T, rs7570267 A/G in IL1F10) in patients with GD.

METHODS

A case-control study was conducted on 132 patients with TAO and 153 patients without TAO according to eligibility criteria. After clinical examination blood samples were collected for further investigations. Genotyping was performed with the TaqMan™ Master Mix kit. Allele and genotype frequencies were compared between studied groups and subgroups.

RESULTS

No significant differences were found in age, duration of GD, or thyroid hormone between patients with and without TAO. However, a higher predisposition to develop TAO was observed among smokers (OR = 1.682, p = 0.03). Overall, no significant associations between gene polymorphisms and TAO development were identified in GD patients. Further analysis revealed that the CC genotype in IL1F10 rs3811058 polymorphism among Caucasians was associated with an increased risk of TAO (OR = 2.7, p = 0.02), as well as allele differences were also significant (OR = 2.8, p = 0.001).

CONCLUSIONS

These findings shed light on TAO genetic predispositions in Kazakhstani GD patients, notably among Caucasians, underscoring the need for further research. These results may offer valuable targets for the development of novel treatments for TAO.

Peripheral CD3+CD4+ T cells as indicators of disease activity in thyroid eye disease: age-dependent significance

PURPOSE

To provide an in-depth analysis of the association of peripheral lymphocytes and the disease activity of thyroid eye disease (TED).

METHODS

This retrospective study enrolled 65 active TED patients and 46 inactive TED patients. Comparative analyses of peripheral lymphocyte subsets were conducted between active and inactive patients. Subgroup analyses were performed based on sex, age, disease duration, and severity. Correlation analyses explored the associations between lymphocyte subsets and TED activity indicators. Prediction models for TED activity were established using objective indicators.

RESULTS

Significantly elevated levels of CD3+CD4+ T cells were observed in active TED patients compared to inactive patients (P = 0.010). Subgroup analyses further revealed that this disparity was most prominent in females (P = 0.036), patients aged 50 years and younger (P = 0.003), those with long-term disease duration (P = 0.022), and individuals with moderate-to-severe disease (P = 0.021), with age exerting the most substantial impact. Subsequent correlation analysis confirmed the positive association between CD3+CD4+ T cells and the magnetic resonance imaging indicator of TED activity among patients aged 50 years and younger (P = 0.038). The combined prediction models for TED activity, established using objective indicators including CD3+CD4+ T cells, yielded areas under curve of 0.786 for all patients and 0.816 for patients aged 50 years and younger.

CONCLUSIONS

Peripheral CD3+CD4+ T cells are associated with disease activity of TED, especially in patients aged 50 years and younger. Our study has deepened the understanding of the peripheral T cell profiles in TED patients.

Role of Inositol-Requiring Enzyme 1 and Autophagy in the Pro-Fibrotic Mechanism Underlying Graves' Orbitopathy

PURPOSE

Orbital fibroblasts play key roles in the pathogenesis of Graves' orbitopathy (GO), and previous findings have shown that endoplasmic reticulum (ER) stress and autophagy also contribute to GO. In this study, we investigated the presently unclear roles of inositol-requiring enzyme 1 (IRE1) and related autophagy processes in the pro-fibrotic mechanism of GO.

MATERIALS AND METHODS

Orbital adipose/connective tissues were obtained from eight GO patients and six normal individuals during surgery. GO fibroblasts were transfected with IRE1 small-interfering RNA and treated with bafilomycin A1 (Baf-A1) to evaluate the inhibitory effects of ER stress and autophagy, and protein-expression levels were analyzed through western blotting after stimulation with transforming growth factor (TGF)-β.

RESULTS

TGF-β stimulation upregulated IRE1 in GO orbital fibroblasts, whereas silencing IRE1 suppressed fibrosis and autophagy responses. Similarly, Baf-A1, an inhibitor of late-phase autophagy, decreased the expression of pro-fibrotic proteins.

CONCLUSION

IRE1 mediates autophagy and the pro-fibrotic mechanism of GO, which provides a more comprehensive interpretation of GO pathogenesis and suggests potential therapeutic targets.

Immune checkpoints: new insights into the pathogenesis of thyroid eye disease

Thyroid eye disease (TED) is a disfiguring autoimmune disease characterized by changes in the orbital tissues and is caused by abnormal thyroid function or thyroid-related antibodies. It is the ocular manifestation of Graves' disease. The expression of thyroid-stimulating hormone receptor (TSHR) and the insulin-like growth factor-1 receptor (IGF-1 R) on the cell membrane of orbital fibroblasts (OFs) is responsible for TED pathology. Excessive inflammation is caused when these receptors in the orbit are stimulated by autoantibodies. CD34+ fibrocytes, found in the peripheral blood and orbital tissues of patients with TED, express immune checkpoints (ICs) like MHC II, B7, and PD-L1, indicating their potential role in presenting antigens and regulating the immune response in TED pathogenesis. Immune checkpoint inhibitors (ICIs) have significantly transformed cancer treatment. However, it can also lead to the occurrence of TED in some instances, suggesting the abnormality of ICs in TED. This review will examine the overall pathogenic mechanism linked to the immune cells of TED and then discuss the latest research findings on the immunomodulatory role of ICs in the development and pathogenesis of TED. This will offer fresh perspectives on the study of pathogenesis and the identification of potential therapeutic targets.

Single-cell BCR and transcriptome analysis reveals peripheral immune signatures in patients with thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is the most prevalent orbital disease in adults caused by an autoimmune disorder, which can lead to disfigurement and vision impairment. Developing effective treatments for this condition presents challenges due to our limited understanding of its underlying immune aberrations. In this study, we profiled the immune components in the peripheral blood of patients with TAO as well as healthy individuals, utilizing single-cell RNA sequencing and B-cell receptor repertoires (BCR) analysis. We observed a significant reduction in the proportions of regulatory B cells (Bregs) and type 2 conventional dendritic cells (DCs) in patients with TAO during the active phase. Conversely, there was a significant increase in the proportion of type 1 DCs. Further analysis of cell differentiation trajectory revealed potential impairment in the transition of B cells towards Breg phenotype during the active phase of TAO. Besides, the activation process of TAO appeared to involve inflammation and immune dysfunction, as indicated by the dynamic changes in the activities of key regulators. The abnormalities in the peripheral immune system, such as the reduced capacity of Bregs to suppress inflammation, were primarily driven by the enhanced interaction among Breg, DCs, and monocytes (i.e., CD22-PTPRC and BTLA-TNFRSF14). Collectively, our findings offer a comprehensive insight into the molecular regulation and cellular reconfiguration during the active phase of TAO at the single-cell level, in order to explore the pathogenesis of TAO and provide new ideas for the future treatment of TAO.

Redox mechanisms in autoimmune thyroid eye disease

Thyroid eye disease (TED) is an autoimmune condition affecting the orbit and the eye with its adnexa, often occurring as an extrathyroidal complication of Graves' disease (GD). Orbital inflammatory infiltration and the stimulation of orbital fibroblasts, triggering de novo adipogenesis, an overproduction of hyaluronan, myofibroblast differentiation, and eventual tissue fibrosis are hallmarks of the disease. Notably, several redox signaling pathways have been shown to intensify inflammation and to promote adipogenesis, myofibroblast differentiation, and fibrogenesis by upregulating potent cytokines, such as interleukin (IL)-1β, IL-6, and transforming growth factor (TGF)-β. While existing treatment options can manage symptoms and potentially halt disease progression, they come with drawbacks such as relapses, side effects, and chronic adverse effects on the optic nerve. Currently, several studies shed light on the pathogenetic contributions of emerging factors within immunological cascades and chronic oxidative stress. This review article provides an overview on the latest advancements in understanding the pathophysiology of TED, with a special focus of the interplay between oxidative stress, immunological mechanisms and environmental factors. Furthermore, cutting-edge therapeutic approaches targeting redox mechanisms will be presented and discussed.

Immunological Processes in the Orbit and Indications for Current and Potential Drug Targets

Thyroid eye disease (TED) is an extrathyroidal manifestation of Graves' disease (GD). Similar to GD, TED is caused by an autoimmune response. TED is an autoimmune inflammatory disorder of the orbit and periorbital tissues, characterized by upper eyelid retraction, swelling, redness, conjunctivitis, and bulging eyes. The pathophysiology of TED is complex, with the infiltration of activated T lymphocytes and activation of orbital fibroblasts (OFs) and autoantibodies against the common autoantigen of thyroid and orbital tissues. Better understanding of the multifactorial pathogenesis of TED contributes to the development of more effective therapies. In this review, we present current and potential drug targets. The ideal treatment should slow progression of the disease with as little interference with patient immunity as possible. In the future, TED treatment will target the immune mechanism involved in the disease and will be based on a strategy of restoring tolerance to autoantigens.

Current and promising therapies based on the pathogenesis of Graves' ophthalmopathy

Graves' ophthalmopathy (GO) is a hyperthyroidism-related and immune-mediated disease that poses a significant threat to human health. The pathogenesis of GO primarily involves T cells, B cells, and fibroblasts, suggesting a pivotal role for the thyrotropin-antibody-immunocyte-fibroblast axis. Traditional treatment approaches for Graves' disease (GD) or GO encompass antithyroid drugs (ATDs), radioactive iodine, and beta-blockers. However, despite decades of treatment, there has been limited improvement in the global incidence of GO. In recent years, promising therapies, including immunotherapy, have emerged as leading contenders, demonstrating substantial benefits in clinical trials by inhibiting the activation of immune cells like Th1 and B cells. Furthermore, the impact of diet, gut microbiota, and metabolites on GO regulation has been recognized, suggesting the potential of non-pharmaceutical interventions. Moreover, as traditional Chinese medicine (TCM) components have been extensively explored and have shown effective results in treating autoimmune diseases, remarkable progress has been achieved in managing GO with TCM. In this review, we elucidate the pathogenesis of GO, summarize current and prospective therapies for GO, and delve into the mechanisms and prospects of TCM in its treatment.

Graves' Orbitopathy Models: Valuable Tools for Exploring Pathogenesis and Treatment

Graves' orbitopathy (GO) is the most common extrathyroidal complication of Graves' disease (GD) and severely affects quality of life. However, its pathogenesis is still poorly understood, and therapeutic options are limited. Animal models are important tools for preclinical research. The animals in some previous models only exhibited symptoms of hyperthyroidism without ocular lesions. With the improvements achieved in modeling methods, some progressive animal models have been established. Immunization of mice with A subunit of the human thyroid stimulating hormone receptor (TSHR) by either adenovirus or plasmid (with electroporation) is widely used and convincing. These models are successful to identify that the gut microbiota influences the occurrence and severity of GD and GO, and sex-related risk factors may be key contributors to the female bias in the occurrence of GO rather than sex itself. Some data provide insight that macrophages and CD8+ T cells may play an important pathogenic role in the early stage of GO. Our team also replicated the time window from GD onset to GO onset and identified a group of CD4+ cytotoxic T cells. In therapeutic exploration, TSHR derived peptides, fingolimod, and rapamycin offer new potential options. Further clinical trials are needed to investigate these drugs. With the increasing use of these animal models and more in-depth studies of the new findings, scientists will gain a clearer understanding of the pathogenesis of GO and identify more treatments for patients.

Gut Microbiome Associated With Graves Disease and Graves Orbitopathy: The INDIGO Multicenter European Study

CONTEXT

Gut bacteria can influence host immune responses but little is known about their role in tolerance-loss mechanisms in Graves disease (GD; hyperthyroidism caused by autoantibodies, TRAb, to the thyrotropin receptor, TSHR) and its progression to Graves orbitopathy (GO).

OBJECTIVE

This work aimed to compare the fecal microbiota in GD patients, with GO of varying severity, and healthy controls (HCs).

METHODS

Patients were recruited from 4 European countries (105 GD patients, 41 HCs) for an observational study with cross-sectional and longitudinal components.

RESULTS

At recruitment, when patients were hyperthyroid and TRAb positive, Actinobacteria were significantly increased and Bacteroidetes significantly decreased in GD/GO compared with HCs. The Firmicutes to Bacteroidetes (F:B) ratio was significantly higher in GD/GO than in HCs. Differential abundance of 15 genera was observed in patients, being most skewed in mild GO. Bacteroides displayed positive and negative correlations with TSH and free thyroxine, respectively, and was also significantly associated with smoking in GO; smoking is a risk factor for GO but not GD. Longitudinal analyses revealed that the presence of certain bacteria (Clostridiales) at diagnosis correlated with the persistence of TRAb more than 200 days after commencing antithyroid drug treatment.

CONCLUSION

The increased F:B ratio observed in GD/GO mirrors our finding in a murine model comparing TSHR-immunized with control mice. We defined a microbiome signature and identified changes associated with autoimmunity as distinct from those due to hyperthyroidism. Persistence of TRAb is predictive of relapse; identification of these patients at diagnosis, via their microbiome, could improve management with potential to eradicate Clostridiales.

Pathophysiology of thyroid-associated orbitopathy

Thyroid-associated orbitopathy, the most common extrathyroidal manifestation of Graves' disease, is characterized by orbital inflammatory infiltration and activation of orbital fibroblasts, which mediates de novo adipogenesis, excessive production of hyaluronan, myofibroblast differentiation and ultimately tissue fibrosis. Interactions among T cells, B cells, and orbital fibroblasts result in their activation and perpetuation of orbital inflammation as well as tissue remodelling. T helper 17 cells belong to a newly identified pathogenic CD4+ T cell subset which possesses prominent pro-inflammatory and profibrotic capabilities. Thyroid stimulating hormone receptor/insulin-like growth factor-1 receptor crosstalk and the downstream signalling pathways of both receptors represent the major mechanisms leading to activation of orbital fibroblasts. Thyroid stimulating hormone receptor autoantibody is the disease specific biomarker of great clinical relevance and utility. There is growing evidence that oxidative stress, gut microbiome and epigenetics also play a role in the pathogenesis and their manipulation may represent novel therapeutic strategies.

M1-Like Macrophages Modulate Fibrosis and Inflammation of Orbital Fibroblasts in Graves' Orbitopathy: Potential Relevance to Soluble Interleukin-6 Receptor

Background: Graves' orbitopathy (GO) is a disfiguring and sight-threatening autoimmune disease. Previous studies have shown the infiltration of macrophages in GO orbital connective tissues. However, the immunophenotypes of macrophages and their modulatory effects on orbital fibroblasts (OFs) have not been examined so far. In this study, we sought to determine the pathophysiology of macrophages in GO. Methods: In this case-control study, orbital connective tissues collected from 40 GO patients and 20 healthy controls were immunohistochemically stained for cytokines and macrophage cell surface antigens. The polarization of orbital-infiltrating macrophages was investigated by flow cytometry and immunofluorescence. Effects of interleukin (IL)-6 combined with soluble IL-6 receptor (sIL-6R) on the proliferation, differentiation, and inflammation of different OF subsets were examined by CCK-8, Western blotting, and Luminex assays, respectively. The antigen-presenting abilities of different OF subsets under IL-6/sIL-6R signaling were studied by proteomics. Finally, the differentiation of CD8⁺ IL-17A-producing T cells by sIL-6R was tested. Results: GO orbital connective tissues displayed increased IL-6, sIL-6R, STAT3, and IL-17A levels. CD86⁺ M1-like macrophages were predominant in active GO patients, while stable GO patients tended to have more CD163⁺ M2-like macrophages. The expression of IL-6 was higher in M1-like macrophages, and the expression of transforming growth factor-β was higher in M2-like macrophages both in GO orbital connective tissues in situ in vivo and in cell culture system in vitro. The IL-6/sIL-6R stimulation promoted the fibrosis of both CD34⁺ and CD34^- OFs. Monocyte chemoattractant protein-1 expression was also induced by IL-6/sIL-6R stimulation in both OF subsets. IL-6/sIL-6R stimulation enhanced the antigen processing of CD34⁺ OFs through upregulating the intact major histocompatibility complex I and antigen transporters. However, the protein expressions of the thyrotropin receptor and insulin-like growth factor 1 receptor could not be directly increased by IL-6/sIL-6R stimulation in CD34⁺ OFs. Furthermore, sIL-6R was conducive to the differentiation of CD8⁺ IL-17A-producing T cells. Conclusions: Our study demonstrated the immunophenotypes of orbital-infiltrating macrophages that may activate OFs depending on the IL-6/sIL-6R signaling in GO. Our preclinical findings implicate, at least in part, the molecular rationale for blocking sIL-6R as a promising therapeutic agent for GO.

Pathogenic role of Th17 cells in autoimmune thyroid disease and their underlying mechanisms

Autoimmune thyroid disease, encompassing Graves' disease and Hashimoto's thyroiditis, has a very complex etiology. Pathogenesis of the disease involves both genetic susceptibility and environmental triggers. Traditionally, imbalance of T helper cell 1 and 2 was thought to result in the immune disorders in Graves' disease and Hashimoto's thyroiditis. However, increasing evidence recently revealed the important role of T helper 17 cell and its relative cellular and secretory components in the pathogenesis and progression of autoimmune thyroid disease. This review is aimed to summarize the published studies on the involvement of T helper 17 cell in autoimmune thyroid disease and discuss the underlying regulatory mechanisms, which could possibly serve as the foundation of discovering new 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 review of TSHR- and IGF-1R-related pathogenesis and treatment of Graves' orbitopathy

Graves' orbitopathy (GO) is an organ-specific autoimmune disease, but its pathogenesis remains unclear. There are few review articles on GO research from the perspective of target cells and target antigens. A systematic search of PubMed was performed, focusing mainly on studies published after 2015 that involve the role of target cells, orbital fibroblasts (OFs) and orbital adipocytes (OAs), target antigens, thyrotropin receptor (TSHR) and insulin-like growth factor-1 receptor (IGF-1R), and their corresponding antibodies, TSHR antibodies (TRAbs) and IGF-1R antibodies (IGF-1R Abs), in GO pathogenesis and the potentially effective therapies that target TSHR and IGF-1R. Based on the results, OFs may be derived from bone marrow-derived CD34+ fibrocytes. In addition to CD34+ OFs, CD34- OFs are important in the pathogenesis of GO and may be involved in hyaluronan formation. CD34- OFs expressing Slit2 suppress the phenotype of CD34+ OFs. β-arrestin 1 can be involved in TSHR/IGF-1R crosstalk as a scaffold. Research on TRAbs has gradually shifted to TSAbs, TBAbs and the titre of TRAbs. However, the existence and role of IGF-1R Abs are still unknown and deserve further study. Basic and clinical trials of TSHR-inhibiting therapies are increasing, and TSHR is an expected therapeutic target. Teprotumumab has become the latest second-line treatment for GO. This review aims to effectively describe the pathogenesis of GO from the perspective of target cells and target antigens and provide ideas for its fundamental treatment.

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.

Immunophenotype of Lacrimal Glands in Graves Orbitopathy: Implications for the Pathogenesis of Th1 and Th17 Immunity

Background: Recent studies have reported a wide spectrum of ocular surface injuries in the context of autoimmune reactions in Graves' orbitopathy (GO). Increased expression of inflammatory mediators in tears of GO patients suggests that the lacrimal glands could be a target for immune responses. However, the immunophenotype for GO lacrimal microenvironment is not known. This study aimed to elucidate the pathological changes of GO lacrimal glands. Methods: In this case-control study, lacrimal glands were surgically collected from GO patients who underwent orbital decompression surgery and control subjects who underwent other ocular-related surgery. Bulk RNA-sequencing, flow cytometry with dimensional reduction, and immunohistochemical and multiplexed stainings were conducted. Western blotting and multipathway assays were performed in CD34⁺ fibroblasts derived from lacrimal and orbital tissues. Results: Increased expression of cytokines and chemokines accompanied by a variety of immune cell infiltrations mainly involving T cells, B cells, and monocytes was found in GO lacrimal glands. An in-depth investigation into T cell subsets revealed interferon (IFN)-γ-producing T helper (Th)1 and interleukin (IL)-17A-producing Th17 cell-dominated autoimmunity in the active GO lacrimal microenvironment. Both fibrosis and adipogenesis were observed in GO lacrimal tissue remodeling. IL-17A, not IFN-γ, stimulated transforming growth factor-β-initiated myofibroblast differentiation as well as 15-deoxy-Δ^12,14-prostaglandin J₂-initiated adipocyte differentiation in CD34⁺ lacrimal fibroblasts (LFs) and orbital fibroblasts (OFs), respectively. IL-17A activated many fibrotic and adipogenic-related signaling pathways in CD34⁺ LFs and OFs. A novel anti-IL-17A monoclonal antibody SHR-1314 could reverse the promoting effect of IL-17A on fibrosis and adipogenesis in CD34⁺ LFs and OFs. Conclusions: Our findings provide evidence for the infiltration of different lymphocytes into GO lacrimal microenvironment, where Th1 and Th17 cells characterize the onset of active lacrimal inflammation and contribute to tissue remodeling. These findings may have potential future therapeutic implications regarding the utility of anti-IL-17A therapy, which should be studied in future research.

Changes in Th9 and Th17 lymphocytes and functional cytokines and their relationship with thyroid-stimulating hormone receptor antibodies at different stages of graves’ disease

Objective

Graves’ disease (GD) is an organ-specific autoimmune disease characterized by the production of thyroid-stimulating antibodies (TSAb). The newly discovered CD4⁺ T helper cells, Th9 and Th17 lymphocytes, have been confirmed to be closely associated with a variety of immune diseases. However, relationships with the onset and development of GD remain unclear. The purpose of this study was to investigate the roles of Th9 and Th17 in the pathogenesis and prognosis of GD.

Patients

We recruited 26 patients with newly diagnosed GD, 45 patients with GD in remission, and 20 healthy individuals.

Measurements

Thyroid function and autoantibodies were evaluated using chemiluminescence immunoassays. Th9 and Th17 cells were analyzed using flow cytometry. The expression of Foxo1, IRF-4, RORc, IL-9, and IL-17 mRNA was examined using real-time PCR, and IL-9 and IL-17 protein levels were measured using enzyme-linked immunosorbent assay.

Results

Th9, Th17, and characteristic cytokines IL-9 and IL-17 in the GD-untreated group were significantly higher than those in the control and remission groups. The above indexes significantly decreased in the remission group, with the levels in the TRAb⁻ remission group being similar to those in the normal group, while in the TRAb⁺ remission group, levels were differentially increased. TRAb titer was positively correlated with the levels of Th9, Th17, and their functional cytokines.

Conclusions

Th9 and Th17 cells may be involved in the pathogenesis and disease outcome of GD, which could provide a new direction for developing immunotherapy for patients with GD.

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.

2021 update on thyroid-associated ophthalmopathy

PURPOSE

Our understanding of thyroid-associated ophthalmopathy (TAO, A.K.A Graves' orbitopathy, thyroid eye disease) has advanced substantially, since one of us (TJS) wrote the 2010 update on TAO, appearing in this journal.

METHODS

PubMed was searched for relevant articles.

RESULTS

Recent insights have resulted from important studies conducted by many different laboratory groups around the World. A clearer understanding of autoimmune diseases in general and TAO specifically emerged from the use of improved research methodologies. Several key concepts have matured over the past decade. Among them, those arising from the refinement of mouse models of TAO, early stage investigation into restoring immune tolerance in Graves' disease, and a hard-won acknowledgement that the insulin-like growth factor-I receptor (IGF-IR) might play a critical role in the development of TAO, stand out as important. The therapeutic inhibition of IGF-IR has blossomed into an effective and safe medical treatment. Teprotumumab, a β-arrestin biased agonist monoclonal antibody inhibitor of IGF-IR has been studied in two multicenter, double-masked, placebo-controlled clinical trials demonstrated both effectiveness and a promising safety profile in moderate-to-severe, active TAO. Those studies led to the approval by the US FDA of teprotumumab, currently marketed as Tepezza for TAO. We have also learned far more about the putative role that CD34+ fibrocytes and their derivatives, CD34+ orbital fibroblasts, play in TAO.

CONCLUSION

The past decade has been filled with substantial scientific advances that should provide the necessary springboard for continually accelerating discovery over the next 10 years and beyond.

Current insights of applying MRI in Graves' ophthalmopathy

Graves' ophthalmopathy (GO) is an autoimmune disease related to Grave's disease (GD). The therapeutic strategies for GO patients are based on precise assessment of the activity and severity of the disease. However, the current assessment systems require development to accommodate updates in treatment protocols. As an important adjunct examination, magnetic resonance imaging (MRI) can help physicians evaluate GO more accurately. With the continuous updating of MRI technology and the deepening understanding of GO, the assessment of this disease by MRI has gone through a stage from qualitative to precise quantification, making it possible for clinicians to monitor the microstructural changes behind the eyeball and better integrate clinical manifestations with pathology. In this review, we use orbital structures as a classification to combine pathological changes with MRI features. We also review some MRI techniques applied to GO clinical practice, such as disease classification and regions of interest selection.

Effect of systemic steroid therapy in Graves' orbitopathy on regulatory T cells and Th17/Treg ratio

PURPOSE

Glucocorticoids are a mainstay treatment for Graves' orbitopathy, yet their exact mechanisms of action remain unclear. We aimed to determine whether the therapeutic effects of systemic steroid therapy in Graves' orbitopathy are mediated by changes in regulatory T lymphocytes (Tregs) and T helper 17 lymphocytes (Th17).

METHODS

We assessed Treg and Th17 levels in the peripheral blood of 32 patients with active, moderate-to-severe Graves' orbitopathy who received 12 weekly pulses of methylprednisolone, and determined their association with disease severity, disease activity, and treatment outcomes. The acute orbitopathy phase was confirmed based on clinical evaluation and magnetic resonance imaging, and assessed using the clinical activity score (CAS). The severity of the disease was classified according to ETA/EUGOGO guidelines, and quantified based on the total eye score. Treatment response was determined based on specific criteria (e.g., changes in CAS score, diplopia grade, visual acuity, etc.). Treg and Th17 cells were identified using flow cytometry.

RESULTS

Methylprednisolone treatment improved the activity of the disease and altered the Th17/Treg balance (i.e., the percentage of Tregs decreased while the number of Th17 cells remained unchanged). There was no association between the Treg/Th17 ratio and the activity and severity of the disease or the treatment response.

CONCLUSIONS

Therapeutic effects of steroid therapy in Graves' orbitopathy are not mediated by Treg and Th17 alterations in the peripheral blood. The decrease in peripheral Treg percentage is likely a consequence of the non-specific effects of steroids and does not impact clinical outcome.

Adipose/Connective Tissue From Thyroid-Associated Ophthalmopathy Uncovers Interdependence Between Methylation and Disease Pathogenesis: A Genome-Wide Methylation Analysis

In response to pathological stimulation, methylation status conversion of the genome drives changes of cell feature and is able to promote disease development. Yet the role of methylation in the development of thyroid-associated ophthalmopathy (TAO) remains to be evaluated. Overexpansion of orbital tissue is the key feature of TAO. In this study, the methylation profile of orbital adipose/connective tissue from TAO patients and normal individuals were compared. After screening 3,739 differentially methylated probes, the distribution and properties of these probes were analyzed. Furthermore, enriched biological functions of these genes associated with differential methylation and the relationship between their methylation status and expression profile were also identified, including PTPRU and VCAM-1. According to our results, methylation was involved in disregulated immune response and inflammation in TAO and might contribute to activation of fibroblast and adipogenesis, leading to the expansion of orbital tissue. Neuropathy and neurobehavioral symptoms were also potentially associated with methylation. These results may help to extend the understanding of methylation in TAO and provide more insights into diagnosis and treatment of patients.

In Search of Excellence: From a Small Clinical Unit to an Internationally Recognized Center for Orbital Diseases Research and Surgery at the Department of Ophthalmology, Shanghai Ninth People's Hospital, China

ABSTRACT

"Where there is a will, there is a way." It is never easy to make progress and development but with full dedication and firm commitment, many aspirations can still be realized. We would like to share with the readers the story of how we develop our division of orbital diseases and surgery from scratch to strengths over a period of 2 decades at the Department of Ophthalmology of Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, China.

Clinical relevance of estimating circulating interleukin-17 and interleukin-23 during methylprednisolone therapy in Graves' orbitopathy: A preliminary study

PURPOSE

Graves' orbitopathy (GO) is an important problem in endocrinology. Currently used methods of assessing the degree of activity of the autoimmune process are not satisfactory. Therefore, there is a need to establish indicators of greater utility.

PATIENTS AND METHODS

The study included 35 patients: 15 with GO, 10 with Graves' disease (GD) without GO and 10 controls. Patients with GO received methylprednisolone (MP) for 12 weeks. Concentrations of thyrotropin receptor antibodies (TSHRab), interleukin 17 (IL-17) and 23 (IL-23) were obtained before administering the first dose of MP, after 6 and 12 weeks of therapy, and 3 months after treatment cessation. Patients were classified as responders (n ​= ​11) if a reduction of ≥2 points in the Clinical Activity Score (CAS) was observed.

RESULTS

A significant decrease in exophthalmos, muscles' thickness and CAS value was demonstrated after MP treatment in responders group. Significantly higher concentrations were found in baseline IL-23 between the GD and GO groups compared to controls. No statistically significant differences in serum concentrations of IL-17 and IL-23 were observed during treatment with MP and 3 months after treatment cessation. A statistically significant reduction in TSHRab concentration was demonstrated 3 months after treatment cessation compared to baseline values in responders group.

CONCLUSIONS

Low baseline IL-17 concentration, in addition to high TSHRab titre, serves as marker of disease activity. Although, we expect that low IL-23 concentration, in addition to high TSHRab titre, could be used as predictors of disease activity and a prognostic factor of response to immunosuppressive therapy in GO.

TGF-β Physiology as a Novel Therapeutic Target Regarding Autoimmune Thyroid Diseases: Where Do We Stand and What to Expect

Transforming growth factor beta (TGF-β), as a master regulator of immune response, is deeply implicated in the complex pathophysiology and development of autoimmune thyroid diseases. Based on the close interplay between thyroid autoimmunity and TGF-β, scientific interest was shifted to the understanding of the possible role of this molecule regarding the diagnosis, prognosis, and therapy of these diseases. The main aim of this review is to present research data about possible treatment options based on the role of TGF-β in thyroid autoimmunity. Suggested TGF-β-mediated therapeutic strategies regarding autoimmune thyroid diseases include either the enhancement of its immunosuppressive role or inhibition of its facilitatory role in thyroid autoimmunity. For example, the application of hr-TGF-β can be used to bolster the inhibitory role of TGF-β regarding the development of thyroid diseases, whereas anti-TGF-β antibodies and similar molecules could impede its immune-promoting effects by blocking different levels of TGF-β biosynthesis and activation pathways. In conclusion, TGF-β could evolve to a promising, novel therapeutic tool for thyroid autoimmunity.

Differential expression and alternative splicing of transcripts in orbital adipose/connective tissue of thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy is a typical autoimmune disease of orbital tissues. Alternative splicing significantly influences many diseases progression, including cancer, age-related macular degeneration, and multiple sclerosis, by modulating the expression of transcripts. However, its role in thyroid-associated ophthalmopathy is still unclear. In this study, differential expression transcripts and differential alternative splicing genes in orbital adipose/connective tissues of thyroid-associated ophthalmopathy patients were detected using RNA sequencing, Cuffdiff, and replicate multivariate analysis of transcript splicing. Three thousand ninety six differential expression transcripts and 2355 differential alternative splicing genes were screened out, while functional enrichment analysis indicated that differential expression transcript and differential alternative splicing genes were associated with immune modulation, extracellular matrix remodeling, and adipogenesis. The expression of the SORBS1, SEPT2, COL12A1, and VCAN gene transcripts was verified by qRT-PCR. In conclusion, prevalent alternative splicing is involved in the disease development in thyroid-associated ophthalmopathy. More attention should be paid to the mechanism of alternative splicing to explore more potential therapeutic targets in thyroid-associated ophthalmopathy.

A novel CD4+ CTL subtype characterized by chemotaxis and inflammation is involved in the pathogenesis of Graves' orbitopathy

Graves' orbitopathy (GO), the most severe manifestation of Graves' hyperthyroidism (GH), is an autoimmune-mediated inflammatory disorder, and treatments often exhibit a low efficacy. CD4+ T cells have been reported to play vital roles in GO progression. To explore the pathogenic CD4+ T cell types that drive GO progression, we applied single-cell RNA sequencing (scRNA-Seq), T cell receptor sequencing (TCR-Seq), flow cytometry, immunofluorescence and mixed lymphocyte reaction (MLR) assays to evaluate CD4+ T cells from GO and GH patients. scRNA-Seq revealed the novel GO-specific cell type CD4+ cytotoxic T lymphocytes (CTLs), which are characterized by chemotactic and inflammatory features. The clonal expansion of this CD4+ CTL population, as demonstrated by TCR-Seq, along with their strong cytotoxic response to autoantigens, localization in orbital sites, and potential relationship with disease relapse provide strong evidence for the pathogenic roles of GZMB and IFN-γ-secreting CD4+ CTLs in GO. Therefore, cytotoxic pathways may become potential therapeutic targets for GO.

Modulating gut microbiota in a mouse model of Graves' orbitopathy and its impact on induced disease

BACKGROUND

Graves' disease (GD) is an autoimmune condition in which autoantibodies to the thyrotropin receptor (TSHR) cause hyperthyroidism. About 50% of GD patients also have Graves' orbitopathy (GO), an intractable disease in which expansion of the orbital contents causes diplopia, proptosis and even blindness. Murine models of GD/GO, developed in different centres, demonstrated significant variation in gut microbiota composition which correlated with TSHR-induced disease heterogeneity. To investigate whether correlation indicates causation, we modified the gut microbiota to determine whether it has a role in thyroid autoimmunity. Female BALB/c mice were treated with either vancomycin, probiotic bacteria, human fecal material transfer (hFMT) from patients with severe GO or ddH2O from birth to immunization with TSHR-A subunit or beta-galactosidase (βgal; age ~ 6 weeks). Incidence and severity of GD (TSHR autoantibodies, thyroid histology, thyroxine level) and GO (orbital fat and muscle histology), lymphocyte phenotype, cytokine profile and gut microbiota were analysed at sacrifice (~ 22 weeks).

RESULTS

In ddH2O-TSHR mice, 84% had pathological autoantibodies, 67% elevated thyroxine, 77% hyperplastic thyroids and 70% orbital pathology. Firmicutes were increased, and Bacteroidetes reduced relative to ddH2O-βgal; CCL5 was increased. The random forest algorithm at the genus level predicted vancomycin treatment with 100% accuracy but 74% and 70% for hFMT and probiotic, respectively. Vancomycin significantly reduced gut microbiota richness and diversity compared with all other groups; the incidence and severity of both GD and GO also decreased; reduced orbital pathology correlated positively with Akkermansia spp. whilst IL-4 levels increased. Mice receiving hFMT initially inherited their GO donors' microbiota, and the severity of induced GD increased, as did the orbital brown adipose tissue volume in TSHR mice. Furthermore, genus Bacteroides, which is reduced in GD patients, was significantly increased by vancomycin but reduced in hFMT-treated mice. Probiotic treatment significantly increased CD25+ Treg cells in orbital draining lymph nodes but exacerbated induced autoimmune hyperthyroidism and GO.

CONCLUSIONS

These results strongly support a role for the gut microbiota in TSHR-induced disease. Whilst changes to the gut microbiota have a profound effect on quantifiable GD endocrine and immune factors, the impact on GO cellular changes is more nuanced. The findings have translational potential for novel, improved treatments. Video abstract.

Mechanisms That Underly T Cell Immunity in Graves' Orbitopathy

Graves' orbitopathy (GO), also known as thyroid-associated ophthalmopathy, is the most common ocular abnormality of Graves' disease. It is a disfiguring, invalidating, and potentially blinding orbital disease mediated by an interlocking and complicated immune network. Self-reactive T cells directly against thyroid-stimulating hormone receptor-bearing orbital fibroblasts contribute to autoimmune inflammation and tissue remodeling in GO orbital connective tissues. To date, T helper (Th) 1 (cytotoxic leaning) and Th2 (antibody leaning) cell subsets and an emerging role of Th17 (fibrotic leaning) cells have been implicated in GO pathogenesis. The potential feedback loops between orbital native residential CD34^- fibroblasts, CD34⁺ infiltrating fibrocytes, and effector T cells may affect the T cell subset bias and the skewed pattern of cytokine production in the orbit, thereby determining the outcomes of GO autoimmune reactions. Characterization of the T cell subsets that drive GO and the cytokines they express may significantly advance our understanding of orbital autoimmunity and the development of promising therapeutic strategies against pathological T cells.

Elevated IL-38 inhibits IL-23R expression and IL-17A production in thyroid-associated ophthalmopathy

IL-23/IL-23R and PGE₂/EP2+EP4 have been recognized as crucial signals that promote Th17 differentiation in many autoimmune diseases, including thyroid-associated ophthalmopathy (TAO). However, the interactive role of IL-23R in IL-23/Th17 signaling and PGE₂/Th17 signaling has not been clarified in TAO. Furthermore, the role of IL-38, a novel anti-inflammatory cytokine, has not been explored in TAO. Thus, we aimed to investigate the roles of IL-23R and IL-38 in the pathogenesis of TAO. Activated peripheral blood mononuclear cells (PBMCs) were cultured with or without IL-23 and PGE₂. The results showed that IL-23R and IL-17A were upregulated to different degrees and reached the highest levels with both stimuli, indicating that IL-23 induced PBMCs to secrete PGE₂, which further boosted the proportion of IL-23R+CD4+T cells to promote IL-17A secretion. Pretreatment with antagonists aimed at EP2/EP4 receptors diminished PGE₂-induced upregulation of IL-23R and IL-17A. IL-38 in TAO patients was increased. Activated orbital fibroblasts (OFs) and PBMCs were pretreated with different concentrations of IL-38. IL-23R and IL-17A expression in circulating PBMCs and IL-6 and IL-8 in resident OFs were suppressed by IL-38 at relatively low concentrations. Our findings suggest that the feedback loop of IL-23/IL-23R/PGE₂/EP2+EP4/IL-23R/IL-17A plays a significant role in the pathogenesis of TAO and that IL-23R is one of the key targets. Increased IL-38 in TAO could not only inhibit the expression of IL-23R and IL-17A in PBMCs but also suppress inflammation in OFs. Therapies targeting IL-23R may be effective, and IL-38 could be a potential therapeutic approach for TAO.

Novel Approaches for Immunosuppression in Graves' Hyperthyroidism and Associated Orbitopathy

BACKGROUND

Both Graves' hyperthyroidism (GH) and Graves' orbitopathy (GO) are associated with significant adverse health consequences. All conventional treatment options have limitations regarding efficacy and safety. Most importantly, they do not specifically address the underlying immunological mechanisms. We aim to review the latest development of treatment approaches in these two closely related disorders.

SUMMARY

Immunotherapies of GH have recently demonstrated clinical efficacy in preliminary studies. They include ATX-GD-59, an antigen-specific immunotherapy which restores immune tolerance to the thyrotropin receptor; iscalimab, an anti-CD40 monoclonal antibody which blocks the CD40-CD154 costimulatory pathway in B-T cell interaction; and K1-70, a thyrotropin receptor-blocking monoclonal antibody. Novel treatment strategies have also become available in GO. Mycophenolate significantly increased the overall response rate combined with standard glucocorticoid (GC) treatment compared to GC monotherapy. Tocilizumab, an anti-interleukin 6 receptor monoclonal antibody, displayed strong anti-inflammatory action in GC-resistant cases. Teprotumumab, an anti-insulin-like growth factor 1 receptor monoclonal antibody, resulted in remarkable improvement in terms of disease activity, proptosis, and diplopia. Further, rituximab appears to be useful in active disease of recent onset without impending dysthyroid optic neuropathy.

KEY MESSAGES

Therapeutic advances will continue to optimize our management of GH and associated orbitopathy in an effective and safe manner.

Proteomics Screening of Differentially Expressed Cytokines in Tears of Patients with Graves' Ophthalmopathy

BACKGROUND

The current study aimed at exploring the cytokine profile in the tears of patients with Graves' ophthalmopathy (GO).

METHODS

Tears were sampled from the eyes of 7 patients with active GO and 7 healthy volunteers using filter paper. Then the levels of up to 34 cytokines in the tears of each subject were detected using high-throughput protein microarray technology in line with the introduction.

RESULTS

The results of cytokine protein microarray screening showed that 10 proteins, namely, CD40, CD40 Ligand, GITR, IL-12p70, IL-1 beta, IL-2, IL-21, IL-6, MIP-3 alpha and TRANCE, were overexpressed (with fold change >1.20) and 3 proteins, namely, GM-CSF, IL-1 sRI and IL-13 were downregulated (with fold change < 0.83) in GO patients. In addition, the protein levels of CD40 and CD40 ligand (CD40L) were significantly different between GO patients and healthy controls (P=0.028 and 0.011, respectively). Further Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of differently expressed proteins showed that these proteins were involved in biological functions including biological processes (positive regulation of cytokine production, JAK-STAT cascade and leukocyte proliferation), molecular functions (cytokine and growth factor receptors binding and cytokine activity), and other important pathways (cytokine-cytokine receptor interaction, JAK-STAT signaling pathway, IL-17 signaling pathway, NF-kappa B signaling pathway, Th17 cell differentiation, and intestinal immune network for IgA production), all of which might be involved in the pathology of GO.

CONCLUSION

Our cytokine protein microarray analysis indicated that several proteins were differentially expressed in GO patients, which provides potential targets for GO prevention.

Progress in the pathogenesis of thyroid-associated ophthalmopathy and new drug development

Thyroid-associated ophthalmopathy (TAO) is the most common extrathyroidal manifestation of toxic diffuse goiter (Graves' disease), also known as Graves' ophthalmopathy/orbitopathy. As an organ-specific autoimmune disease, the pathogenesis of TAO is still unclear. In recent years, great progress has been made in revealing the mechanism of TAO. Various biological and immunosuppressive agents have emerged in an endless stream, showing encouraging results. Strengthening the basic research, establishing ideal animal models, deeply understanding the pathogenesis, and developing novel targeted drugs are of great significance to guide the clinical diagnosis and management of TAO and improve the prognosis of patients.

Evidence for Associations Between Th1/Th17 "Hybrid" Phenotype and Altered Lipometabolism in Very Severe Graves Orbitopathy

PURPOSE

The purpose of this article is to investigate the characteristics of Th1-cell and Th17-cell lineages for very severe Graves orbitopathy (GO) development.

METHODS

Flow cytometry was performed with blood samples from GO and Graves disease (GD) patients and healthy controls, to explore effector T-cell phenotypes. Lipidomics was conducted with serum from very severe GO patients before and after glucocorticoid (GC) therapy. Immunohistochemistry and Western blotting were used to examine orbital-infiltrating Th17 cells or in vitro models of Th17 polarization.

RESULTS

In GD, Th1 cells predominated in peripheral effector T-cell subsets, whereas in GO, Th17-cell lineage predominated. In moderate-to-severe GO, Th17.1 cells expressed retinoic acid receptor-related orphan receptor-γt (RORγt) independently and produced interleukin-17A (IL-17A), whereas in very severe GO, Th17.1 cells co-expressed RORγt and Tbet and produced interferon-γ (IFN-γ). Increased IFN-γ-producing Th17.1 cells positively correlated with GO activity and were associated with the development of very severe GO. Additionally, GC therapy inhibited both Th1-cell and Th17-cell lineages and modulated a lipid panel consisting of 79 serum metabolites. However, in GC-resistant, very severe GO, IFN-γ-producing Th17.1 cells remained at a high level, correlating with increased serum triglycerides. Further, retro-orbital tissues from GC-resistant, very severe GO were shown to be infiltrated by CXCR3+ Th17 cells expressing Tbet and STAT4 and rich in triglycerides that promoted Th1 phenotype in Th17 cells in vitro.

CONCLUSIONS

Our findings address the importance of Th17.1 cells in GO pathogenesis, possibly promoting our understanding of the association between Th17-cell plasticity and disease severity of GO.

Ocular conditions and dry eye due to traditional and new forms of smoking: A review

Addiction to cigarette smoking has high prevalence rates recorded worldwide. Smoking has been linked to several life-threatening systemic conditions such as cancer, heart attack and stroke, in addition to a range of ocular pathologies. In recent years, electronic cigarettes (EC) have emerged as alternatives to smoking. ECs are nicotine delivery devices which produce an aerosol by heating, rather than combusting, a liquid which contains nicotine, flavours and preservatives. This review focuses on the association of traditional and new forms of smoking with dry eye disease, contact lens wear and four other common ocular diseases: cataract, age-related macular degeneration, glaucoma and Graves' ophthalmopathy. It is concluded that smoking and vaping appear as a risk factor for the aforementioned ocular conditions. An evidence-based, clear link between cigarette smoking, or EC vaping and ocular problems is yet to be discovered.

Fibrosis in dysthyroid eye disease

Dysthyroid eye disease is a rare condition, mainly found in people with Graves' hyperthyroidism. Autoimmune responses to thyroid/orbit shared antigens drive extensive tissue remodelling. This includes excess adipogenesis and over-production of extra-cellular matrix, which both tend to occur in the earlier 'active' inflammatory stages of disease. With time these give way to fibrosis, which has a profound impact on eye motility and may be life-long. Progress has been made in identifying the shared autoantigen(s) and the role of specific T cells and autoantibodies in remodelling, which have facilitated development of novel therapies. However relatively little is known of the autoimmune processes under-pinning fibrosis and currently there are no adequate medical treatments.

Immunohistochemical analysis of human orbital tissue in Graves' orbitopathy

PURPOSE

Immunohistochemistry of orbital tissues offers a correlation between the microscopic changes and macroscopic clinical manifestation of Graves' orbitopathy (GO). Summarizing the participation of different molecules will help us to understand the pathogenesis of GO.

METHODS

The pertinent and current literature on immunohistochemistry of human orbital tissue in GO was reviewed using the NCBI PubMed database.

RESULTS

33 articles comprising over 700 orbital tissue samples were included in this review. The earliest findings included the demonstration of HLA-DR and T cell (to a lesser extent B cell) markers in GO orbital tissues. Subsequent investigators further contributed by characterizing cellular infiltration, confirming the presence of HLA-DR and TSHR, as well as revealing the participation of cytokines, growth factors, adhesion molecules and miscellaneous substances. HLA-DR and TSHR are over-expressed in orbital tissues of GO patients. The inflammatory infiltration mainly comprises CD4 + T cells and macrophages. Cytokine profile suggests the importance of Th1 (especially in early active phase) and Th17 immunity in the pathogenesis of GO. Upregulation of proinflammatory/profibrotic cytokines, adhesion molecules and growth factors finally culminate in activation of orbital fibroblasts and perpetuation of orbital inflammation. The molecular status of selected parameters correlates with the clinical presentation of GO.

CONCLUSION

Further investigation is warranted to define precisely the role of different molecules and ongoing search for new players yet to be discovered is also important. Unfolding the molecular mechanisms behind GO will hopefully provide insights into the development of novel therapeutic strategies and optimize our clinical management of the disease.

New insights into the pathogenesis and nonsurgical management of Graves orbitopathy

Graves orbitopathy, also known as thyroid eye disease or thyroid-associated orbitopathy, is visually disabling, cosmetically disfiguring and has a substantial negative impact on a patient's quality of life. There is increasing awareness of the need for early diagnosis and rapid specialist input from endocrinologists and ophthalmologists. Glucocorticoids are the mainstay of treatment; however, recurrence occurs frequently once these are withdrawn. Furthermore, in >60% of cases, normal orbital anatomy is not restored, and skilled rehabilitative surgery is required. Clinical trials have shown that considerable benefit can be derived from the addition of antiproliferative agents (such as mycophenolate or azathioprine) in preventing deterioration after steroid cessation. In addition, targeted biologic therapies have shown promise, including teprotumumab, which reduces proptosis, rituximab (anti-CD20), which reduces inflammation, and tocilizumab, which potentially benefits both of these parameters. Other strategies such as orbital radiotherapy have had their widespread role in combination therapy called into question. The pathophysiology of Graves orbitopathy has also been revised with identification of new potential therapeutic targets. In this Review we provide an up-to-date overview of the field, outline the optimal management of Graves orbitopathy and summarize the research developments in this area to highlight future research questions and direct future clinical trials.