Circulating Microvesicles Regulate Treg and Th17 Differentiation in Human Autoimmune Thyroid Disorders

A systematic review of dysregulated microRNAs in Hashimoto's thyroiditis

BACKGROUND

Plenty of evidence suggests that dysregulated microRNAs are linked to developing autoimmune thyroid diseases. In this study, we aimed to identify commonly linked dysregulated microRNAs in Hashimoto's thyroiditis(HT) and explore microRNA-targeted genes and the involved pathways.

METHODS

Embase, PubMed, Web of Science, and Scopus databases were searched using the MeSH terms and free text terms, which yielded 11879 articles published up to July 2023. Two-step screening(first for titles and second for abstracts) was completed according to inclusion and exclusion criteria. The search strategy was formulated using the PEO format(Population, Exposure, and Outcome) for observational studies. The corresponding target genes and relevant signaling pathways were also identified using web servers of Diana Tools/its mirPath v.3 software, miRNA Enrichment Analysis, Mirpath DB2, miRPathDB 2.0, and miRmap.

RESULTS

Review inclusion criteria were met by 16 studies. Thirty-three microRNAs were identified as differentially expressed in HT patients compared to a healthy control after qRT-PCR or RNA sequencing confirmation. Only three miR-146a, miR-142, and miR-301 showed significant results in more than two studies comparing HT cases with healthy controls.

CONCLUSION

Three key microRNAs in HT were identified by systematic review; the corresponding target genes and signaling pathways involved in the target genes were also identified. These microRNAs regulate the immune response and inflammation and may favor the development and progression of HT. These data may be beneficial to make a step forward to understand the exact etiology of HT and use of these MicroRNAs as possible diagnostic and prognostic biomarkers and as target therapy.

Potential involvement of circulating exosomal miRNA-146a in disease activity and TRAF6 gene expression in juvenile proliferative lupus nephritis

BACKGROUND

Juvenile SLE (JSLE) is a complex autoimmune disorder that predominantly affects children and adolescents with several unique challenges, and microRNA-146a (miRNA-146a) might be an interesting anti-inflammatory molecule. Because exosomes in the blood might protect miRNAs, the association between circulating exosomal miRNA-146a and lupus proinflammatory genes, such as IRAK1 and TRAF6, was studied in peripheral blood mononuclear cells from people with JSLE.

METHODS

Blood samples from 12 patients were collected every 3 months until 1 year with the recorded disease activity, and quantitative real-time PCR was used to determine the circulating exosomal miRNA-146a and the gene expression (IRAK1 and TRAF6).

RESULTS

The mean age was 12.60±0.43 years at diagnosis and all patients had a complete response at 12 months. According to the nanoparticle tracking analysis, the abundance of exosomes was significantly lower at 3, 6 and 12 months compared with 0 months, while the level of circulating exosomal miRNA-146a was significantly higher at 12 months than at diagnosis (p<0.001). There was a negative correlation between the level of circulating exosomal miRNA-146a expression and the level of TRAF6 mRNA (r=-0.30, p=0.049). Moreover, there were correlations between circulating exosomal miRNA-146a and disease severity such as SLE Disease Activity Index 2000 score, anti-double-stranded DNA antibody and proteinuria (urine protein-creatinine ratio), respectively. Therefore, increasing the level of circulating exosomal miRNA-146a, which might control TRAF6 mRNA expression, could have an effect on the production of inflammatory cytokines.

CONCLUSION

This suggests that miRNA-146a might serve as a non-invasive biomarker to evaluate the response to treatment in patients with juvenile lupus nephritis.

Clinical and molecular impact of concurrent thyroid autoimmune disease and thyroid cancer: From the bench to bedside

The recent incorporation of immune checkpoint inhibitors targeting the PD-1 (programmed cell death receptor 1) and CTLA-4 (cytotoxic T lymphocyte antigen 4) pathways into the therapeutic armamentarium of cancer has increased the need to understand the correlation between the immune system, autoimmunity, and malignant neoplasms. Both autoimmune thyroid diseases and thyroid cancer are common clinical conditions. The molecular pathology of autoimmune thyroid diseases is characterized by the important impact of the PD-1/PD-L1 axis, an important inhibitory pathway involved in the regulation of T-cell responses. Insufficient inhibitory pathways may prone the thyroid tissue to a self-destructive immune response that leads to hypothyroidism. On the other hand, the PD-1/PD-L1 axis and other co-inhibitory pathways are the cornerstones of the immune escape mechanisms in thyroid cancer, which is a mechanism through which the immune response fails to recognize and eradicate thyroid tumor cells. This common mechanism raises the idea that thyroid autoimmunity and thyroid cancer may be opposite sides of the same coin, meaning that both conditions share similar molecular signatures. When associated with thyroid autoimmunity, thyroid cancer may have a less aggressive presentation, even though the molecular explanation of this clinical consequence is unclear. More studies are warranted to elucidate the molecular link between thyroid autoimmune disease and thyroid cancer. The prognostic impact that thyroid autoimmune disease, especially chronic lymphocytic thyroiditis, may exert on thyroid cancer raises important insights that can help physicians to better individualize the management of patients with thyroid cancer.

Regulatory T Cells in the Pathogenesis of Graves' Disease

Maintaining a delicate balance between the prompt immune response to pathogens and tolerance towards self-antigens and commensals is crucial for health. T regulatory (Treg) cells are pivotal in preserving self-tolerance, serving as negative regulators of inflammation through the secretion of anti-inflammatory cytokines, interleukin-2 neutralization, and direct suppression of effector T cells. Graves' disease (GD) is a thyroid-specific autoimmune disorder primarily attributed to the breakdown of tolerance to the thyroid-stimulating hormone receptor. Given the limitations of currently available GD treatments, identifying potential pathogenetic factors for pharmacological targeting is of paramount importance. Both functional impairment and frequency reduction of Tregs seem likely in GD pathogenesis. Genome-wide association studies in GD have identified polymorphisms of genes involved in Tregs' functions, such as CD25 (interleukin 2 receptor), and Forkhead box protein P3 (FOXP3). Clinical studies have reported both functional impairment and a reduction in Treg frequency or suppressive actions in GD, although their precise involvement remains a subject of debate. This review begins with an overview of Treg phenotype and functions, subsequently delves into the pathophysiology of GD and into the existing literature concerning the role of Tregs and the balance between Tregs and T helper 17 cells in GD, and finally explores the ongoing studies on target therapies for GD.

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.

MicroRNAs in autoimmune thyroid diseases and their role as biomarkers

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the posttranscriptional level. They are emerging as potential biomarkers and as therapeutic targets for several diseases including autoimmune thyroid diseases (AITD). They control a wide range of biological phenomena, including immune activation, apoptosis, differentiation and development, proliferation and metabolism. This function makes miRNAs attractive as disease biomarker candidates or even as therapeutic agents. Because of their stability and reproducibility circulating miRNAs have been an interesting area of research in many diseases, and studies describing their role in the immune response and in autoimmune diseases have progressively developed. The mechanisms underlying AITD remain elusive. AITD pathogenesis is characterized by a multifactorial interplay based on the synergy between susceptibility genes and environmental stimulation, together with epigenetic modulation. Understanding the regulatory role of miRNAs could lead to identify potential susceptibility pathways, diagnostic biomarkers and therapeutic targets for this disease. Herein we update our present knowledge on the role of microRNAs in AITD and discuss on their importance as possible diagnostic and prognostic biomarkers in the most prevalent AITDs: Hashimoto's thyroiditis (HT), Graves' disease (GD) and Graves' Ophthalmopathy (GO). This review provides an overview of the state of the art in the pathological roles of microRNAs as well as in possible novel miRNA-based therapeutic approaches in AITD.

Role of Extracellular Vesicles in Thyroid Physiology and Diseases: Implications for Diagnosis and Treatment

Extracellular vesicles are spherical subcellular structures delimited by a lipid bilayer and released by most cells in the human body. They are loaded with a myriad of molecules (i.e., nucleic acids and proteins) depending on their cell of origin and provide the ability to transmit a message to surrounding or distant target cells. In several organs, including the thyroid, abundant recent literature reports that extracellular vesicles are responsible for intercellular communication in physiological and pathological processes, and that their utilization as a potential biomarker of pathological states (i.e., cancer, autoimmune diseases) or as therapeutic delivery vehicles promise clinical options. In this review, we present the current knowledge and understanding regarding the role of extracellular vesicles in developing thyroid diseases and diagnosis.

Extracellular Vesicles From Kidney Allografts Express miR-218-5p and Alter Th17/Treg Ratios

Delayed graft function (DGF) in kidney transplantation is associated with ischemic injury and carries long term functional and immunological risks. Extracellular vesicles (EV) released from allografts may signal a degree of ischemic stress, and are thought to play an important role in the development of anti-donor immunity. Here, we show that kidney perfusate-derived extracellular vesicles (KP-EV) express donor-specific human leukocyte antigen. KP-EV from kidneys that experience DGF increase the T-helper 17 (Th17) to T-regulatory (Treg) ratio in third party peripheral blood mononuclear cells to a greater degree than those from kidneys with immediate function. We report miR-218-5p upregulation in KP-EV of kidney transplant recipients with DGF. Levels of miR-218-5p in KP-EV inversely correlated with recipient eGFR at multiple time points following transplantation. Additionally, the degree of increase in Th17/Treg ratio by KP-EV positively correlated with miR-218-5p expression in KP-EV samples. Taken together, these data provide evidence that KP-EV may contribute to modulating immune responses in transplant recipients. This could lead to novel intervention strategies to inhibit DGF in order to improve graft function and survival.

Research progress on the role and mechanism of action of exosomes in autoimmune thyroid disease

Exosomes are widely distributed extracellular vesicles (EVs), which are currently a major research hotspot for researchers based on their wide range of sources, stable membrane structure, low immunogenicity, and containing a variety of biomolecules. A large number of literatures have shown that exosomes and exosome cargoes (especially microRNAs) play an important role in the activation of inflammation, development of tumor, differentiation of cells, regulation of immunity and so on. Studies have found that exosomes can stimulate the immune response of the body and participate in the occurrence and development of various diseases, including autoimmune diseases. Furthermore, the potential of exosomes as therapeutic tools in various diseases has also attracted much attention. Autoimmune thyroid disease (AITD) is one of the most common autoimmune diseases, mainly composed of Graves' disease (GD) and Hashimoto's thyroiditis (HT), which affects the health of many people and has a genetic predisposition, but its pathogenesis is still being explored. Starting from the relevant biological characteristics of exosomes, this review summarizes the current research status of exosomes and the association between exosomes and some diseases, with a focus on the situation of AITD and the potential role of exosomes (including substances in their vesicles) in AITD in combination with the current published literature, aiming to provide new directions for the pathogenesis, diagnosis or therapy of AITD.Supplemental data for this article is available online at.

Extracellular Vesicles as Signal Carriers in Malignant Thyroid Tumors?

Extracellular vesicles (EVs) are small, membranous structures involved in intercellular communication. Here, we analyzed the effects of thyroid cancer-derived EVs on the properties of normal thyroid cells and cells contributing to the tumor microenvironment. EVs isolated from thyroid cancer cell lines (CGTH, FTC-133, 8505c, TPC-1 and BcPAP) were used for treatment of normal thyroid cells (NTHY), as well as monocytes and endothelial cells (HUVEC). EVs' size/number were analyzed by flow cytometry and confocal microscopy. Gene expression, protein level and localization were investigated by qRT-PCR, WB and ICC/IF, respectively. Proliferation, migration and tube formation were analyzed. When compared with NTHY, CGTH and BcPAP secreted significantly more EVs. Treatment of NTHY with cancer-derived EVs changed the expression of tetraspanin genes, but did not affect proliferation and migration. Cancer-derived EVs suppressed tube formation by endothelial cells and did not affect the phagocytic index of monocytes. The number of 6 μm size fraction of cancer-derived EVs correlated negatively with the CD63 and CD81 expression in NTHY cells, as well as positively with angiogenesis in vitro. Thyroid cancer-derived EVs can affect the expression of tetraspanins in normal thyroid cells. It is possible that 6 μm EVs contribute to the regulation of NTHY gene expression and angiogenesis.

HIV-Sheltering Platelets From Immunological Non-Responders Induce a Dysfunctional Glycolytic CD4+ T-Cell Profile

Immunological non-responders (InRs) are HIV-infected individuals in whom the administration of combination antiretroviral therapy (cART), although successful in suppressing viral replication, cannot properly reconstitute patient circulating CD4⁺ T-cell number to immunocompetent levels. The causes for this immunological failure remain elusive, and no therapeutic strategy is available to restore a proper CD4⁺ T-cell immune response in these individuals. We have recently demonstrated that platelets harboring infectious HIV are a hallmark of InR, and we now report on a causal connection between HIV-containing platelets and T-cell dysfunctions. We show here that in vivo, platelet–T-cell conjugates are more frequent among CD4⁺ T cells in InRs displaying HIV-containing platelets (<350 CD4⁺ T cells/μl blood for >1 year) as compared with healthy donors or immunological responders (IRs; >350 CD4⁺ T cells/μl). This contact between platelet containing HIV and T cell in the conjugates is not infectious for CD4⁺ T cells, as coculture of platelets from InRs containing HIV with healthy donor CD4⁺ T cells fails to propagate infection to CD4⁺ T cells. In contrast, when macrophages are the target of platelets containing HIV from InRs, macrophages become infected. Differential transcriptomic analyses comparing InR and IR CD4⁺ T cells reveal an upregulation of genes involved in both aerobic and anaerobic glycolysis in CD4⁺ T cells from InR vs. IR individuals. Accordingly, InR platelets containing HIV induce a dysfunctional increase in glycolysis-mediated energy production in CD4⁺ T cells as compared with T cells cocultured with IR platelets devoid of virus. In contrast, macrophage metabolism is not affected by platelet contact. Altogether, this brief report demonstrates a direct causal link between presence of HIV in platelets and T-cell dysfunctions typical of InR, contributing to devise a platelet-targeted therapy for improving immune reconstitution in these individuals.

The Roles of Exosomes in Immunoregulation and Autoimmune Thyroid Diseases

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

The pathogenic, therapeutic and diagnostic role of exosomal microRNA in the autoimmune diseases

Exosomes are a nano-vesicle surrounded by a bilipid layer that can release from almost all cells and could be detected in tissues and biological liquids. These vesicles contain lipids, proteins, and nucleic acids (including DNA, mRNA, and miRNA) inside and on the exosomes' surface constitute their content. Exosomes can transfer their cargo into the recipient cell, which can modify recipient cells' biological activities. Recently it has been deciphering that the miRNA pattern of exosomes reveals the cellular pathophysiological situation and modifies various biological processes. Increasing data regarding exosomes highlights that the exosomes and their cargo, especially miRNAs, are implicated in the pathophysiology of various disorders, such as autoimmune disease. The current evidence on the deciphering of mechanisms in which exosomal miRNAs contributed to autoimmunity was indicated that exosomal miRNA might hold information that can reprogram the function of many of the immune cells involved in autoimmune diseases' pathogenesis. In the present study, we summarized the pathogenic role of exosomal miRNAs in several autoimmune diseases, including myasthenia gravis (MG), psoriasis, inflammatory bowel disease (IBD), type 1 diabetes (T1D), multiple sclerosis (MS), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjogren's Syndrome (SS), systemic sclerosis (SSc), vitiligo, and autoimmune thyroid diseases (AITD). Moreover, in this work, we present evidence of the potential role of exosomal miRNAs as therapeutic and diagnostic agents in autoimmune diseases.

Correlation and integration of circulating miRNA and peripheral whole blood gene expression profiles in patients with venous thromboembolism

The main aim of this work was to evaluate differential expression and biological functions of circulating miRNA and whole peripheral blood (PB) genes in patients affected by venous thromboembolism (VTE) and in healthy subjects. Circulating miRNA sequences and PB expression profiles were obtained from GEO datasets. Ten miRNAs with the most significant differential expression rate (dif-miRNA) were subjected to miRbase to confirm their identity. Dif-miRNA targets were predicted by TargetScan and aligned with differentially expressed genes to obtain overlapping co-genes. Biological functions of co-genes were analyzed by Gene Ontology and KEGG analysis. Interaction network of dif-miRNAs, co-genes, and their downstream pathways were studied by analyzing protein-protein interaction (PPI) clusters (STRING) and determining the crucial hubs (Cytoscape).MiR-522-3p and miR-134 dif-miRNAs are involved in protein translation and apoptosis by regulating their respective co-genes in PB. Co-genes are present in nucleolus and extracellular exosomes and are involved in oxidative phosphorylation and ribosome/poly(A)-RNA organization. The predicted PPI network covered 107 clustered genes and 220 marginal joints, where ten hub genes participating in PPIs were found. All these hub genes were down-regulated in VTE patients. Our study identifies new miRNAs as potential biological markers and therapeutic targets for VTE.

Circulating Exosomes From Patients With Graves' Disease Induce an Inflammatory Immune Response

Exosomes are extracellular vesicles that can participate in autoimmune diseases. The purpose of this study was to explore whether circulating exosomes are involved in Graves' disease (GD) pathogenesis. In this study, serum exosomes were extracted from 26 healthy controls (HC-EXO), 26 GD patients (GD-EXO), and 7 Graves' ophthalmopathy patients (GO-EXO). For each group, the total protein content was detected, and thyrotropin receptor, insulin-like growth factor 1 receptor (IGF-1R), heat shock protein 60 (HSP60), and cluster of differentiation (CD) 63 expression were analyzed by Western blotting (WB). Healthy volunteer-derived peripheral blood mononuclear cells (PBMCs) and HC-EXO or GD-EXO were cocultured for 24 h, and immunofluorescence was used to observe the locations of the exosomes and toll-like receptor (TLR) 2/3. CD11c+TLR2+ and CD11c+TLR3+ cell percentages were determined by flow cytometry. Myeloid differentiation factor 88 (MyD88), toll/interleukin (IL)-1 receptor domain-containing adaptor inducing interferon-β (TRIF) and p-P65 expression were analyzed by WB. IL-6 and IL-1β supernatant levels were detected using enzyme-linked immunosorbent assay. The results showed that the total protein concentration was similar among GD-EXO, GO-EXO, and HC-EXO. IGF-1R and HSP60 expression was significantly higher in GD-EXO and GO-EXO than in HC-EXO. After coculturing PBMCs with GD-EXO or HC-EXO for 24 h, GD-EXO could bind to TLR2/3. GD-EXO significantly increased CD11c+TLR2+ and CD11c+TLR3+ cell percentages; MyD88, TRIF, and p-P65 protein expression; and IL-6 and IL-1β levels. In conclusion, we first demonstrated that GD-EXO and GO-EXO highly expressed IGF-1R and HSP60. GD-EXO may induce an inflammatory response through the TLR/NF-κB signaling pathway and be involved in the pathogenesis of GD.

MicroRNA-146a-5p enhances T helper 17 cell differentiation via decreasing a disintegrin and metalloprotease 17 level in primary sjögren's syndrome

In clinical practice, we found that microRNA (miR)-146a-5p is significantly up-regulated in peripheral blood mononuclear cells (PBMCs) of primary sjögren’s syndrome (pSS) patients. In vitro experiments confirmed that miR-146a-5p promotes T helper 17 (Th17) cell differentiation, but the specific mechanism is still unknown. To solve this problem, 20 pSS patients and 20 healthy subjects were enrolled in this study and PBMCs were isolated from their blood. The expression of the membrane IL-23 R (mIL-23 R) in PBMCs was determined. CD3⁺ T cells were also isolated and used to further analyze the relationship between the ectodomain shedding of mIL-23 R and a disintegrin and metalloprotease 17 (ADAM17). Finally, miR-146a-5p inhibitor and mimics were transfected into PBMCs to evaluate the relationship between ADAM17 and mIL-23 R, and explore the role of mIL-23 R and ADAM17 in Th17 cell differentiation. Our results revealed a significantly increased expression of miR-146a-5p in PBMCs from pSS patients and significantly increased percentage of Th17 cells compared to PBMCs from healthy controls. Under polarization culture conditions, pSS patient-derived PBMCs can more easily differentiate into Th17 cells, which was, to a great extent, attributable to the increased expression of mIL-23 R. Moreover, ADAM17, an ectodomain sheddase of mIL-23 R, was targeted and negatively regulated by miR-146a-5p, which reduced the ectodomain shedding of mIL-23 R. Overall, our results suggested that miR-146a-5p could promote Th17 cell differentiation through targeting and negatively regulating ADAM17. Thus, these results might offer a new approach in the treatment of pSS.

Role of Extracellular Vesicles in Autoimmune Pathogenesis

Autoimmune diseases are conditions that emerge from abnormal immune responses to natural parts of the body. Extracellular vesicles (EVs) are membranous structures found in almost all types of cells. Because EVs often transport “cargo” between cells, their ability to crosstalk may be an important communication pathway within the body. The pathophysiological role of EVs is increasingly recognized in autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, Type 1 diabetes, and autoimmune thyroid disease. EVs are considered as biomarkers of these diseases. This article outlines existing knowledge on the biogenesis of EVs, their role as messegers in cellular communication and the function in T/B cell differentiation and maturation, and focusing on their potential application in autoimmune diseases.

Emerging Roles for Noncoding RNAs in Autoimmune Thyroid Disease

Autoimmune thyroid disease (AITD) is one of the most frequent autoimmune disorders. However, the pathogenesis of AITD has not been fully elucidated. Recently, accumulating evidence has demonstrated that abnormal expression of noncoding RNAs (ncRNAs) is closely related to the etiopathogenesis of AITD. microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) are 3 major groups of ncRNAs that are attracting increasing attention. Herein, we summarized our present knowledge on the role of miRNAs, lncRNAs, and circRNAs in AITD. This review focused on the importance of ncRNAs in development of the most prevalent AITD, such as Hashimoto disease and Graves' diseases. Altogether, the main purpose of this review is to provide new insights in the pathogenesis of AITD and the possibility of developing novel potential therapeutic targets.

Thyrocyte-derived exosome-targeted dendritic cells stimulate strong CD4+ T lymphocyte responses

Exosomes have been intensively studied in autoimmune diseases, and circulating exosomes and microvesicles have also been explored in autoimmune thyroiditis (AITD). However, the role of thyroid cell-derived exosomes in immune responses is unclear. We showed that IFN-γ-treated Nthy-ori 3-1 cell-derived exosomes (IFN-γ-Exo) harbored TPO, HSP60 and MHC-II and activated dendritic cells (DCs) in vitro. Compared with Exo-targeted DCs (DC_Exo), IFN-γ-Exo-targeted DCs (DC_IFN-γ-Exo) promoted the expression and release of proinflammatory cytokines, such as IFN-γ, IL-17A and IL-22, from CD4⁺ T lymphocytes and inhibited the expression and release of anti-inflammatory cytokines, such as IL-4, IL-10 and TGF-β1; however, IFN-γ-Exo did not have this effect compared with Nthy-ori 3-1 cell-derived exosomes (Exo). DC_IFN-γ-Exo stimulates the expression and release of cytokines from CD4⁺ T lymphocytes more efficiently than IFN-γ-Exo. Thus, DC_IFN-γ-Exo may effectively induce CD4⁺ T lymphocyte-mediated immune responses and play a role in the occurrence and development of AITD.

Circulating Exosomes Activate Dendritic Cells and Induce Unbalanced CD4+ T Cell Differentiation in Hashimoto Thyroiditis

OBJECTIVE

This study explored whether circulating exosomes effectively participate in the inflammatory response in Hashimoto thyroiditis (HT).

DESIGN

Exosomes were extracted from the serum of 30 patients with HT and 30 healthy control (HC) subjects. The expression of thyroperoxidase (TPO), thyroglobulin, high mobility group box 1 (HMGB1), heat shock protein 60 (HSP60), major histocompatibility complex class II (MHC-II), and intercellular adhesion molecule 1 (ICAM1) in exosomes was determined by Western blotting. Flow cytometry and immunofluorescence were performed to confirm that exosomes were taken up by healthy peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs). Then, either DCs or PBMCs were stimulated with HT exosomes (serum exosomes from patients with HT) or HC exosomes (serum exosomes from HC subjects) in the presence or absence of Toll-like receptor (TLR)2/3 inhibitors.

RESULTS

TPO, HSP60, and MHC-II expression was higher in HT exosomes than in HC exosomes. Exosomes were mainly taken up by CD14+ monocytes and CD11c+ DCs. After DCs were stimulated by HT exosomes, significant elevations were observed in MyD88, TRIF, and p-P65 expression; median fluorescence intensity of CD40 and CD83; and IL-6 production. After stimulating PBMCs with HT exosomes, CD11c+TLR2+/TLR3+ and CD4+IFN-γ+Th1/IL-17A+Th17A cell percentages were significantly elevated, and CD4+CD25+Foxp3+ Treg cell percentage was significantly decreased. HT exosomes induced increased IL-17A and IFN-γ production, whereas IL-10 production was suppressed. However, addition of TLR2 or TLR3 inhibitor reversed most of the abovementioned results.

CONCLUSIONS

Our study demonstrates that HT exosomes can present antigens to DCs and bind TLR2/3, causing DC activation via the nuclear factor κB signaling pathway, leading to an imbalance in CD4+ T lymphocyte differentiation, and potentially contributing to HT onset.

Autophagy enhances mesenchymal stem cell-mediated CD4+ T cell migration and differentiation through CXCL8 and TGF-β1

BACKGROUND

Mesenchymal stem cells (MSCs) have been recognized as a promising tool for the treatment of various inflammatory disorders and autoimmune diseases. Stress conditions affect immune-mediated treatment and activate autophagy in MSCs. However, whether autophagy affects the MSC-mediated recruitment and differentiation of CD4⁺ T cells remains elusive.

METHODS

MSCs were pretreated with 3-methyladenine (3-MA) and rapamycin to regulate autophagy, and then co-cultured with CD4⁺ T cells. CD4⁺ T cell migration and differentiation were detected by flow cytometry. Further, gene expression levels of well-known chemokines were analyzed by quantitative real-time PCR. Enzyme-linked immunosorbent assays and western blot analysis were performed to detect C-X-C motif chemokine ligand 8 (CXCL8) and transforming growth factor (TGF)-β1 protein levels. An exogenous antibody and short hairpin RNA were used to regulate CXCL8 and TGF-β1 levels, which enabled us to evaluate how autophagy affected MSC-mediated CD4⁺ T cell migration and differentiation.

RESULTS

3-MA inhibited autophagy in MSCs, which was activated by rapamycin. Rapamycin increased the migration of CD4⁺ T cells, whereas 3-MA decreased their migration. Mechanistically, we found that autophagy strengthened CXCL8 secretion, and the addition of exogenous CXCL8 and an anti-CXCL8 antibody eliminated the difference of CD4⁺ T cell migration among groups. Further, the ratio of regulatory T (Treg) cells was increased in rapamycin-pretreated MSCs, but the ratio of T helper 1 (Th1) cells was decreased, while pretreatment of MSCs with 3-MA induced the opposite effect compared with the control group. TGF-β1 overexpression and knockdown using lentiviruses rectified the differences in the ratios of Treg and Th1 cells among the groups.

CONCLUSION

This study demonstrates that autophagy of mesenchymal stem cells mediates CD4⁺ T cell migration and differentiation through CXCL8 and TGF-β1, respectively. These results provide a potential new strategy for improving MSC-mediated therapy.

Extracellular vesicles in autoimmune vasculitis - Little dirts light the fire in blood vessels

Systemic vasculitis is diverse group of autoimmune disorders which are characterized by inflammation of blood vessel walls with deep aching and burning pain. Their underlying etiology and pathophysiology still remain poorly understood. Extracellular vesicles (EVs), including exosomes, microvesicles (MVs), and apoptotic bodies, are membrane vesicular structures that are released either during cell activation, or when cells undergo programmed cell death, including apoptosis, necroptosis, and pyroptosis. Although EVs were thought as cell dusts, but now they have been found to be potently active since they harbor bioactive molecules, such as proteins, lipids, nucleic acids, or multi-molecular complexes. EVs can serve as novel mediators for cell-to-cell communications by delivery bioactive molecules from their parental cells to the recipient cells. Earlier studies mainly focused on MVs budding from membrane surface. Recent studies demonstrated that EVs may also carry molecules from cytoplasm or even from nucleus of their parental cells, and these EVs may carry autoantigens and are important in vasculitis. EVs may play important roles in vasculitis through their potential pathogenic involvements in inflammation, autoimmune responses, procoagulation, endothelial dysfunction/damage, angiogenesis, and intimal hyperplasia. EVs have also been used as specific biomarkers for diagnostic use or disease severity monitoring. In this review, we have focused on the aspects of EV biology most relevant to the pathogenesis of vasculitis, discussed their perspective insights, and summarized the exist literature on EV relevant studies in vasculitis, therefore provides an integration of current knowledge regarding the novel role of EVs in systemic vasculitis.

Patients With Autoimmune Thyroiditis Show Diminished Levels and Defective Suppressive Function of Tr1 Regulatory Lymphocytes

CONTEXT

T regulatory type 1 (Tr1) cells are a subpopulation of T lymphocytes (CD4+CD49+LAG-3+IL-10+) that exert a considerable immunosuppressive effect. However, their possible role in autoimmune thyroid disease (AITD) has not been explored so far.

PURPOSE

To analyze the levels and function of Tr1 cells in peripheral blood and thyroid tissue of patients with AITD.

DESIGN

Cases and controls, observational study.

SETTING

Department of Endocrinology, Hospital Universitario de la Princesa, Madrid, Spain.

PATIENTS

Thirty-eight patients with AITD (23 with Graves disease and 15 with Hashimoto thyroiditis) and 26 controls.

INTERVENTION

Multiparametric flow cytometry and immunofluorescence techniques were used to analyze the levels in peripheral blood (n = 38) and thyroid mononuclear cells (n = 5). An in vitro assay of suppression of cellular activation and cytokine release was performed to study the function of Tr1 cells.

MAIN OUTCOME MEASURE

Levels and function of Tr1 cells in patients with AITD and controls.

RESULTS

Levels of Tr1 cells were significantly diminished in peripheral blood from patients with AITD. Functional studies showed that Tr1 cells from patients with AITD exhibit a diminished suppressive function compared with healthy controls. Tr1 levels were associated with disease severity, including longer duration of the disease and ophthalmopathy activity, and with autoantibody titers.

CONCLUSIONS

The low levels of Tr1 cells and their diminished function may have a relevant role in the defective immune-regulatory function characteristic of patients with AITD.

Genome-wide Integration Study of Circulating miRNAs and Peripheral Whole-Blood mRNAs of Male Acute Ischemic Stroke Patients

Several circulating microRNAs (miRNAs) have been proved to serve as stable biomarkers in blood for acute ischemic stroke (AIS). However, the functions of these biomarkers remain elusive. By conducting the integration analysis of circulating miRNAs and peripheral whole-blood mRNAs using bioinformatics methods, we explored the biological role of these circulating markers in peripheral whole blood at the genome-wide level. Stroke-related circulating miRNA profile data (GSE86291) and peripheral whole-blood mRNA expression data (GSE16561) were collected from the Gene Expression Omnibus (GEO) datasets. We selected male patients to avoid any gender differences in stroke pathology. Male stroke-related miRNAs (M-miRNAs) and mRNAs (M-mRNAs) were detected using GEO2R. Nine M-miRNAs (five up- and four down-regulated) were applied to TargetScan to predict the possible target mRNAs. Next, we intersected these targets with the M-mRNAs (38 up- and three down-regulated) to obtain the male stroke-related overlapped mRNAs (Mo-mRNAs). Finally, we analyzed biological functions of Mo-mRNAs using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and constructed networks among the Mo-mRNAs, overlapped M-miRNAs (Mo-miRNAs), and their functions. The Mo-mRNAs were enriched in functions such as platelet degranulation, immune response, and pathways associated with phagosome biology and Staphylococcus aureus infection. This study provides an integrated view of interactions among circulating miRNAs and peripheral whole-blood mRNAs involved in the pathophysiological processes of male AIS.

Human Endothelial Cells Modulate CD4+ T Cell Populations and Enhance Regulatory T Cell Suppressive Capacity

Endothelial cells (ECs) line the luminal surface of blood vessels and have an active role in the recruitment of leukocytes, including immune cell activation. Regulatory T cells (Tregs) are immune suppressor cells that maintain peripheral tolerance and must interact with the endothelium as they traffic into tissue. We hypothesized that human ECs could modulate Tregs and their suppressor function. Cocultures of CD4⁺ T cells with human umbilical vein ECs (HUVECs) or dermal microvascular ECs (HDMECs) were conducted and analyzed for activation and proliferation after 72 and 120 h using flow cytometry. In monocyte-depleted cultures, human ECs were found to support CD4⁺ T cell proliferation in the presence of external mitogens phytohemagglutinin or anti-CD3/28 antibodies (aCD3/28). Activation was shown by CD25 expression in these cells that also transiently expressed the Treg transcription factor FOXP3. HUVECs supported the specific concurrent proliferation of both effector T cells and Tregs when cocultured with aCD3/28. Purified Tregs were also functionally activated by prior coculture with EC to suppress effector T (Teff) cell proliferation. Both direct coculture and indirect coculture of EC and Treg showed activation of the Treg suppressive phenotype. However, whereas HUVEC showed enhancement of suppression by both mechanisms, HDMEC only supported Treg suppressive activity via the contact-independent mechanism. In the contact-independent cultures, the soluble mediators IL-6, GM-CSF, or G-CSF released from ECs following interferon-γ activation were not responsible for the enhanced Treg suppressor function. Following direct coculture, Treg expression of inhibitory receptors PD-1 and OX40 was elevated while activated EC expressed the counter ligands programmed death ligand (PD-L)1 and PD-L2. Therefore, human ECs have a role in supporting T cell proliferation and increasing Treg suppressor function. This ability of EC to enhance Treg function could offer novel targets to boost Treg activity during inflammatory disorders.

A MicroRNA Signature for Evaluation of Risk and Severity of Autoimmune Thyroid Diseases

CONTEXT

Circulating microRNAs (miRNAs) are emerging as an interesting research area because of their potential role as novel biomarkers and therapeutic targets. Their involvement in autoimmune thyroid diseases (AITDs) has not been fully explored.

OBJECTIVE

To compare the expression profile of miRNAs in thyroid tissue from patients with AITD and controls, using next-generation sequencing, further validated our findings in thyroid and serum samples.

DESIGN

Twenty fresh-frozen thyroid tissues (15 from patients with AITD and 5 from controls) were used for miRNA next-generation sequencing. Thirty-six thyroid samples were recruited for the qRT-PCR validation test and 58 serum samples for further validation in peripheral blood.

RESULTS

Expression of several miRNAs that had been previously associated with relevant immunological functions was significantly dysregulated. Specifically, eight differentially expressed miRNAs (miR-21-5p, miR-142-3p, miR-146a-5p, miR-146b-5p, miR-155-5p, miR-338-5p, miR-342-5p, and miR-766-3p) were confirmed using qRT-PCR in thyroid samples, and three had the same behavior in tissue and serum samples (miR-21-5p, miR-142-3p, and miR-146a-5p). Furthermore, when the expression of these miRNAs was assessed together with five additional ones previously related to AITD in peripheral blood, the expression of five (miR-Let7d-5p, miR-21-5p, miR-96-5p, miR-142-3p, and miR-301a-3p) was significantly expressed in AITD and, in patients with Graves disease (GD), was correlated with a higher severity of disease, including active ophthalmopathy, goiter, higher antibody titers, and/or higher recurrence rates.

CONCLUSIONS

The present findings identify a serum five-signature miRNA that could be an independent risk factor for developing AITD and a predisposition of a worse clinical picture in patients with GD.

Noncoding RNAs Carried by Extracellular Vesicles in Endocrine Diseases

RNA molecules are essential and fine regulators of important biological processes. Their role is well documented also in the endocrine system, both in physiological and pathological conditions. Increasing interest is arising about the function and the importance of noncoding RNAs shuttled by extracellular vesicles (EVs). In fact, EV membrane protects nucleic acids from enzyme degradation. Nowadays, the research on EVs and their cargoes, as well as their biological functions, faces the lack of standardization in EV purification. Here, the main techniques for EV isolation are discussed and compared for their advantages and vulnerabilities. Despite the possible discrepancy due to methodological variability, EVs and their RNA content are reported to be key mediators of intercellular communication in pathologies of main endocrine organs, including the pancreas, thyroid, and reproductive system. In particular, the present work describes the role of RNAs contained in EVs in pathogenesis and progression of several metabolic dysfunctions, including obesity and diabetes, and their related manifestations. Their importance in the establishment and progression of thyroid autoimmunity disorders and complicated pregnancy is also discussed. Preliminary studies highlight the attractive possibility to use RNAs contained in EVs as biomarkers suggesting their exploitation for new diagnostic approaches in endocrinology.

The cell biology of the thyroid-disrupting mechanism of dichlorodiphenyltrichloroethane (DDT)

OBJECTIVE

Dichlorodiphenyltrichloroethane (DDT) is an organochlorine known for its pesticide properties and for its negative effects on human health. It was banned in most countries for its toxicity to the endocrine system, but due to its persistence at clinically relevant concentrations in both soil and animal tissues, DDT is still linked to several health and social problems.

METHODS

We have previously shown that DDT exposure is causally related to the extracellular release of vesicular organelles such as microvesicles and/or exosomes by using immunocytochemistry with gold-tagged antibodies and various fluorescent membrane markers.

RESULTS

It is now well recognized that microvesicles and/or exosomes organelles are implicated in cell-to-cell communication, and that they are fundamental elements for transferring proteins, RNA, DNA, lipids and transcriptional factors among cells. In this short review, we discussed the role of extracellular vesicle formation in the thyroid-disrupting mechanism of DDT. In particular, we described how DDT, by dislodging the thyrotropin hormone (TSH) receptor from the raft containing compartments of the cells, prevents its activation and internalization.

CONCLUSION

Based on our earlier finding and on the large body of evidence here reviewed, we propose that DDT-induced formation of extracellular vesicles containing the TSH receptor could be directly involved in the development of autoimmune responses against the TSH receptor and that, therefore, their release could lead to the development of the Graves' disease.

Autoimmune thyroid diseases and Th17/Treg lymphocytes

Years of researches have demonstrated that the imbalance of Th17 and Tregs contribute to the thyroid autoimmunity and the severity of autoimmune thyroid disease (AITD). The underlying mechanism comprises inherent genetic predisposition, abnormality of Th17 and Treg related biological molecules, and gut microbiota disorder. New therapeutic strategies have been developed to improve the Th17/Treg equilibrium, including regulation of intracellular signaling pathways, neutralization of Th17-related cytokines, as well as manipulation of Th17 and Treg specific transcription factors. Although a few of these agents are applied into AITD, the clinic prospect is promising.

The Emerging Role of Epigenetics in Autoimmune Thyroid Diseases

Autoimmune thyroid diseases (AITD) are a group of both B cell- and T cell-mediated organ-specific autoimmune diseases. Graves’ disease and Hashimoto thyroiditis are the two main clinical presentations of AITD. Both genetic and environmental factors have important roles in the development of AITD. Epigenetics have been considered to exert key roles in integrating those genetic and environmental factors, and epigenetic modifications caused by environmental factors may drive genetically susceptibility individuals to develop AITD. Recent studies on the epigenetics of AITD have provided some novel insights into the pathogenesis of AITD. The aim of this review is to provide an overview of recent advances in the epigenetic mechanisms of AITD, such as DNA methylation, histone modifications, and non-coding RNAs. This review highlights the key roles of epigenetics in the pathogenesis of AITD and potential clinical utility. However, the epigenetic roles in AITD are still not fully elucidated, and more researches are needed to provide further deeper insights into the roles of epigenetics in AITD and to uncover new therapeutic targets. Although there are many studies assessing the epigenetic modifications in AITD patients, the clinical utility of epigenetics in AITD remains poorly defined. More studies are needed to identify the underlying epigenetic modifications that can contribute to accurate diagnosis of AITD, adequate choice of treatment approach, and precise prediction of treatment outcomes.

Circulating MicroRNAs in Graves' Disease in Relation to Clinical Activity

BACKGROUND

Understanding the roles of circulating microRNAs (miRNAs) can provide important and novel information regarding disease pathogenesis and a patient's clinical condition. Circulating miRNAs, such as exosomal miRNA, may regulate various bioactivities related to intercellular communication. However, the circulation of miRNAs in Graves' disease (GD) in relation to disease activity has never been elucidated. This study aimed to identify circulating miRNAs in GD in relation to disease activity and whether their exosomes play a role in the pathogenesis of GD.

METHODS

Circulating miRNAs were measured in serum obtained from seven intractable GD patients, seven GD patients in remission, and seven healthy controls using the miScript miRNA PCR Array. Altered miRNAs selected from array data were validated in 65 subjects. To investigate exosome biology, peripheral blood mononuclear cells (PBMCs) were incubated with exosomes isolated from the subjects' sera. mRNAs were quantified for cytokines using quantitative real-time polymerase chain reaction.

RESULTS

Circulating miR-23b-5p and miR-92a-39 were increased in GD patients in remission compared with intractable GD patients (p < 0.05). On the other hand, let-7g-3p and miR-339-5p were decreased in GD patients in remission compared with intractable GD patients (p < 0.05). Exosomes from intractable GD patients stimulated mRNA expression for IL-1β and TNF-α compared with GD patients in remission or healthy controls.

CONCLUSIONS

This study demonstrates that different levels of circulating miRNAs are associated with intractable GD. Moreover, serum exosomes of patients with intractable GD may activate immune cells, which may play an important role in GD pathogenesis.

Pathogenesis of thyroid autoimmune disease: the role of cellular mechanisms

Hashimoto's thyroiditis (HT) and Graves' disease (GD) are two very common organ-specific autoimmune diseases which are characterized by circulating antibodies and lymphocyte infiltration. Although humoral and cellular mechanisms have been classically considered separately in the pathogenesis of autoimmune thyroid diseases (AITD), recent research suggests a close reciprocal relationship between these two immune pathways. Several B- and T-cell activation pathways through antigen-presenting cells (APCs) and cytokine production lead to specific differentiation of T helper (Th) and T regulatory (Treg) cells. This review will focus on the cellular mechanisms involved in the pathogenesis of AITD. Specifically, it will provide reasons for discarding the traditional simplistic dichotomous view of the T helper type 1 and 2 pathways (Th1/Th2) and will focus on the role of the recently characterized T cells, Treg and Th17 lymphocytes, as well as B lymphocytes and APCs, especially dendritic cells (DCs).