SIRT1-Regulated Abnormal Acetylation of FOXP3 Induces Regulatory T-Cell Function Defect in Hashimoto's Thyroiditis

The causal effects between autoimmune thyroid disease and urticaria: evidence from a Mendelian randomization study

Previous studies have suggested a comorbidity between autoimmune thyroid disease (AITD) and urticaria. However, the causal effects between AITD and urticaria remain unclear. This study employed genome-wide association study (GWAS) data to analyze the associations between AITD and urticaria through bidirectional Mendelian randomization (MR), meanwhile, examined the role of 731 immune traits as mediators between the two diseases through mediation analysis. The IVW results indicated that Graves' disease (GD) and Hashimoto's thyroiditis (HT) have a potential risk effect on urticaria, particularly increasing the risk of other and unspecified urticaria and idiopathic urticaria. Urticaria, mainly other and unspecified urticaria, dermatographic urticaria demonstrated a potential risk effect on HT. The mediation analysis revealed that GD likely increases the risk of other and unspecified urticaria by reducing CD4-CD8- Natural Killer T Absolute Counts, and reduces the levels of three types of T cells thereby increasing the risk of idiopathic urticaria. HT increased the risk of idiopathic urticaria through reducing the levels of two types of myeloid Dendritic Cells. The study revealed both GD and HT have causal associations with urticaria, particularly with other and unspecified urticaria and idiopathic urticaria. GD and HT may elevate the risk of spontaneous urticaria by regulating different immune traits.

3D-hUMSCs Exosomes Ameliorate Vitiligo by Simultaneously Potentiating Treg Cells-Mediated Immunosuppression and Suppressing Oxidative Stress-Induced Melanocyte Damage

Vitiligo is an autoimmune disease characterized by epidermal melanocyte destruction, with abnormal autoimmune responses and excessive oxidative stress as two cardinal mechanisms. Human umbilical mesenchymal stem cells-derived exosomes (hUMSCs-Exos) are regarded as promising therapeutic choice for autoimmune diseases due to potent immunosuppressive and anti-oxidative properties, which can be potentiated under 3D cell culture condition. Nevertheless, whether exosomes derived from 3D spheroids of hUMSCs (3D-Exos) exhibit considerable therapeutic effect on vitiligo and the underlying mechanism remain elusive. In this study, systemic administration of 3D-Exos showed a remarkable effect in treating mice with vitiligo, as revealed by ameliorated skin depigmentation, less CD8+T cells infiltration, and expanded Treg cells in skin, and 3D-Exos exerted a better effect than 2D-Exos. Mechanistically, 3D-Exos can prominently facilitate the expansion of Treg cells in vitiligo lesion and suppress H2O2-induced melanocytes apoptosis. Forward miRNA profile analysis and molecular experiments have demonstrated that miR-132-3p and miR-125b-5p enriched in 3D-Exos greatly contributed to these biological effects by targeting Sirt1 and Bak1 respectively. In aggregate, 3D-Exos can efficiently ameliorate vitiligo by simultaneously potentiating Treg cells-mediated immunosuppression and suppressing oxidative stress-induced melanocyte damage via the delivery of miR-132-3p and miR-125b-5p. The employment of 3D-Exos will be a promising treament for vitiligo.

Unraveling the molecular architecture of autoimmune thyroid diseases at spatial resolution

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

The dual role of regulatory T cells in hepatitis B virus infection and related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a major contributor to cancer-related deaths worldwide. Hepatitis B virus (HBV) infection is a major etiologic factor leading to HCC. While there have been significant advancements in controlling HBV replication, achieving a complete cure for HBV-related HCC (HBV-HCC) remains an intricate challenge. HBV persistence is attributed to a myriad of mechanisms, encompassing both innate and adaptive immune responses. Regulatory T cells (Tregs) are pivotal in upholding immune tolerance and modulating excessive immune activation. During HBV infection, Tregs mediate specific T cell suppression, thereby contributing to both persistent infection and the mitigation of liver inflammatory responses. Studies have demonstrated an augmented expression of circulating and intrahepatic Tregs in HBV-HCC, which correlates with impaired CD8+ T cell function. Consequently, Tregs play a dual role in the context of HBV infection and the progression of HBV-HCC. In this comprehensive review, we discuss pertinent studies concerning Tregs in HBV infection, HBV-related cirrhosis and HCC. Furthermore, we summarize Treg responses to antiviral therapy and provide Treg-targeted therapies specific to HBV and HCC.

Targeting post-translational modifications of Foxp3: a new paradigm for regulatory T cell-specific therapy

A healthy immune system is pivotal for the hosts to resist external pathogens and maintain homeostasis; however, the immunosuppressive tumor microenvironment (TME) damages the anti-tumor immunity and promotes tumor progression, invasion, and metastasis. Recently, many studies have found that Foxp3+ regulatory T (Treg) cells are the major immunosuppressive cells that facilitate the formation of TME by promoting the development of various tumor-associated cells and suppressing the activity of effector immune cells. Considering the role of Tregs in tumor progression, it is pivotal to identify new therapeutic drugs to target and deplete Tregs in tumors. Although several studies have developed strategies for targeted deletion of Treg to reduce the TME and support the accumulation of effector T cells in tumors, Treg-targeted therapy systematically affects the Treg population and may lead to the progression of autoimmune diseases. It has been understood that, nevertheless, in disease conditions, Foxp3 undergoes several definite post-translational modifications (PTMs), including acetylation, glycosylation, phosphorylation, ubiquitylation, and methylation. These PTMs not only elevate or mitigate the transcriptional activity of Foxp3 but also affect the stability and immunosuppressive function of Tregs. Various studies have shown that pharmacological targeting of enzymes involved in PTMs can significantly influence the PTMs of Foxp3; thus, it may influence the progression of cancers and/or autoimmune diseases. Overall, this review will help researchers to understand the advances in the immune-suppressive mechanisms of Tregs, the post-translational regulations of Foxp3, and the potential therapeutic targets and strategies to target the Tregs in TME to improve anti-tumor immunity.

Sirtuin family in autoimmune diseases

In recent years, epigenetic modifications have been widely researched. As humans age, environmental and genetic factors may drive inflammation and immune responses by influencing the epigenome, which can lead to abnormal autoimmune responses in the body. Currently, an increasing number of studies have emphasized the important role of epigenetic modification in the progression of autoimmune diseases. Sirtuins (SIRTs) are class III nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylases and SIRT-mediated deacetylation is an important epigenetic alteration. The SIRT family comprises seven protein members (namely, SIRT1-7). While the catalytic core domain contains amino acid residues that have remained stable throughout the entire evolutionary process, the N- and C-terminal regions are structurally divergent and contribute to differences in subcellular localization, enzymatic activity and substrate specificity. SIRT1 and SIRT2 are localized in the nucleus and cytoplasm. SIRT3, SIRT4, and SIRT5 are mitochondrial, and SIRT6 and SIRT7 are predominantly found in the nucleus. SIRTs are key regulators of various physiological processes such as cellular differentiation, apoptosis, metabolism, ageing, immune response, oxidative stress, and mitochondrial function. We discuss the association between SIRTs and common autoimmune diseases to facilitate the development of more effective therapeutic strategies.

miR-142-3p encapsulated in T lymphocyte-derived tissue small extracellular vesicles induces Treg function defect and thyrocyte destruction in Hashimoto's thyroiditis

BACKGROUND

Hashimoto's thyroiditis (HT) is an organ-specific autoimmune disease characterized by lymphocyte infiltration that destroys thyrocyte cells. The aim of the present study was to elucidate the role and mechanisms of tissue small extracellular vesicle (sEV) microRNAs (miRNAs) in the pathogenesis of HT.

METHODS

Differentially expressed tissue sEV miRNAs were identified between HT tissue and normal tissue by RNA sequencing in the testing set (n = 20). Subsequently, using quantitative real-time polymerase chain reaction (qRT‒PCR) assays and logistic regression analysis in the validation set (n = 60), the most relevant tissue sEV miRNAs to HT were verified. The parental and recipient cells of that tissue sEV miRNA were then explored. In vitro and in vivo experiments were further performed to elucidate the function and potential mechanisms of sEV miRNAs that contribute to the development of HT.

RESULTS

We identified that miR-142-3p encapsulated in T lymphocyte-derived tissue sEVs can induce Treg function defect and thyrocyte destruction through an intact response loop. Inactivation of miR-142-3p can effectively protect non-obese diabetic (NOD).H-2^h4 mice from HT development display reduced lymphocyte infiltration, lower antibody titers, and higher Treg cells. Looking at the mechanisms underlying sEV action on thyrocyte destruction, we found that the strong deleterious effect mediated by tissue sEV miR-142-3p is due to its ability to block the activation of the ERK1/2 signaling pathway by downregulating RAC1.

CONCLUSIONS

Our findings highlight the fact that tissue sEV-mediated miR-142-3p transfer can serve as a communication mode between T lymphocytes and thyrocyte cells in HT, favoring the progression of HT.

SIRT1 downregulation provokes immune-inflammatory responses in hair follicle outer root sheath cells and may contribute to development of alopecia areata

BACKGROUND

Silent information regulator 1 (SIRT1), a type III histone deacetylase, is involved in various cutaneous and systemic autoimmune diseases including systemic lupus erythematosus, rheumatoid arthritis, and psoriasis. However, little is known about the role of SIRT1 in the development of alopecia areata (AA).

OBJECTIVES

This study investigated whether SIRT1 regulates the hair follicle immune system and is involved in AA pathogenesis.

METHODS

SIRT1 expression in human scalp tissue was analyzed using immunohistochemical staining, qPCR, and western blotting. The regulatory effect of SIRT1 was evaluated after stimulation with the double-stranded RNA mimic polyinosinic:polycytidylic acid (poly I:C) in hair follicle outer root sheath (ORS) cells and C3H/HeJ mice.

RESULTS

SIRT1 expression was significantly reduced in the AA scalp compared to the normal scalp. SIRT1 inhibition upregulated MHC class I polypeptide-related sequence A and UL16 binding protein 3 in hair follicle ORS cells. SIRT1 inhibition also promoted the production of Th1 cytokines (IFN-γ and TNF-α), IFN-inducible chemokines (CXCL9 and CXCL10), and T cell migration in ORS cells. Conversely, SIRT1 activation suppressed the autoreactive inflammatory responses. The counteractive effect of the immune response by SIRT1 was mediated through the deacetylation of NF-κB and phosphorylation of STAT3.

CONCLUSION

SIRT1 downregulation induces immune-inflammatory responses in hair follicle ORS cells and may contribute to AA development.

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

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

Epigenetic regulation and T-cell responses in endometriosis – something other than autoimmunity

Endometriosis is defined as the presence of endometrial-like glands and stroma located outside the uterine cavity. This common, estrogen dependent, inflammatory condition affects up to 15% of reproductive-aged women and is a well-recognized cause of chronic pelvic pain and infertility. Despite the still unknown etiology of endometriosis, much evidence suggests the participation of epigenetic mechanisms in the disease etiopathogenesis. The main rationale is based on the fact that heritable phenotype changes that do not involve alterations in the DNA sequence are common triggers for hormonal, immunological, and inflammatory disorders, which play a key role in the formation of endometriotic foci. Epigenetic mechanisms regulating T-cell responses, including DNA methylation and posttranslational histone modifications, deserve attention because tissue-resident T lymphocytes work in concert with organ structural cells to generate appropriate immune responses and are functionally shaped by organ-specific environmental conditions. Thus, a failure to precisely regulate immune cell transcription may result in compromised immunological integrity of the organ with an increased risk of inflammatory disorders. The coexistence of endometriosis and autoimmunity is a well-known occurrence. Recent research results indicate regulatory T-cell (Treg) alterations in endometriosis, and an increased number of highly active Tregs and macrophages have been found in peritoneal fluid from women with endometriosis. Elimination of the regulatory function of T cells and an imbalance between T helper cells of the Th1 and Th2 types have been reported in the endometria of women with endometriosis-associated infertility. This review aims to present the state of the art in recognition epigenetic reprogramming of T cells as the key factor in the pathophysiology of endometriosis in the context of T-cell-related autoimmunity. The new potential therapeutic approaches based on epigenetic modulation and/or adoptive transfer of T cells will also be outlined.

Bone Mesenchymal Stem Cell-Derived Exosome-Enclosed miR-181a Induces CD4+CD25+FOXP3+ Regulatory T Cells via SIRT1/Acetylation-Mediated FOXP3 Stabilization

Bone marrow mesenchymal stem cells (BMSCs) have been identified as a potential therapeutic approach to immune-related diseases. Here, we show that BMSC-derived exosomes promote FOXP3 expression and induce the conversion of CD4⁺ T cells into CD4⁺CD25⁺FOXP3⁺ Treg cells, which is significant for immunosuppressive activity. We found that miR-181a-5p is upregulated in BMSC-derived exosomes and can be transferred to CD4⁺ T cells. In CD4⁺ cells, miR-181a directly targets SIRT1 and suppresses its expression. Moreover, downregulated SIRT1 enhances FOXP3 via protein acetylation. In conclusion, our data demonstrated that BMSC-derived exosomal miR-181a is critical in the maintenance of immune tolerance. Furthermore, our results reveal that BMSC-derived exosomal miR-181a induces the production of CD4⁺CD25⁺FOXP3⁺ Treg cells via SIRT1/acetylation/FOXP3.

Regulatory T Cells in Autoimmune Vasculitis

Blood vessels are indispensable for host survival and are protected from inappropriate inflammation by immune privilege. This protection is lost in patients with autoimmune vasculitides, a heterogeneous group of diseases causing damage to arteries, arterioles, and capillaries. Vasculitis leads to vascular wall destruction and/or luminal occlusion, resulting in hemorrhage and tissue ischemia. Failure in the quantity and quality of immunosuppressive regulatory T cells (Treg) has been implicated in the breakdown of the vascular immune privilege. Emerging data suggest that Treg deficiencies are disease-specific, affecting distinct pathways in distinct vasculitides. Mechanistic studies have identified faulty CD8+ Tregs in Giant Cell Arteritis (GCA), a vasculitis of the aorta and the large aortic branch vessels. Specifically, aberrant signaling through the NOTCH4 receptor expressed on CD8+ Treg cells leads to rerouting of intracellular vesicle trafficking and failure in the release of immunosuppressive exosomes, ultimately boosting inflammatory attack to medium and large arteries. In Kawasaki’s disease, a medium vessel vasculitis targeting the coronary arteries, aberrant expression of miR-155 and dysregulated STAT5 signaling have been implicated in undermining CD4+ Treg function. Explorations of mechanisms leading to insufficient immunosuppression and uncontrolled vascular inflammation hold the promise to discover novel therapeutic interventions that could potentially restore the immune privilege of blood vessels and pave the way for urgently needed innovations in vasculitis management.

The Importance of the Transcription Factor Foxp3 in the Development of Primary Immunodeficiencies

Transcription factors are an extremely important group of proteins that are responsible for the process of selective activation or deactivation of other cellular proteins, usually at the last stage of signal transmission in the cell. An important family of transcription factors that regulate the body's response is the FOX family which plays an important role in regulating the expression of genes involved in cell growth, proliferation, and differentiation. The members of this family include the intracellular protein Foxp3, which regulates the process of differentiation of the T lymphocyte subpopulation, and more precisely, is responsible for the development of regulatory T lymphocytes. This protein influences several cellular processes both directly and indirectly. In the process of cytokine production regulation, the Foxp3 protein interacts with numerous proteins and transcription factors such as NFAT, nuclear factor kappa B, and Runx1/AML1 and is involved in the process of histone acetylation in condensed chromatin. Malfunctioning of transcription factor Foxp3 caused by the mutagenesis process affects the development of disorders of the immune response and autoimmune diseases. This applies to the impairment or inability of the immune system to fight infections due to a disruption of the mechanisms supporting immune homeostasis which in turn leads to the development of a special group of disorders called primary immunodeficiencies (PID). The aim of this review is to provide information on the role of the Foxp3 protein in the human body and its involvement in the development of two types of primary immunodeficiency diseases: IPEX (Immunodysregulation Polyendocrinopathy Enteropathy X-linked syndrome) and CVID (Common Variable Immunodeficiency).

Exosomes Secreted by Mesenchymal Stem Cells Induce Immune Tolerance to Mouse Kidney Transplantation via Transporting LncRNA DANCR

Mesenchymal stem cells induce kidney transplant tolerance by increasing regulatory T (Treg) cells. Bone marrow mesenchymal stem cell exosomes (BMMSC-Ex) promote Treg cell differentiation. Long non-coding RNA differentiation antagonizing non-protein coding RNA (DANCR) is expressed in BMMSCs and can be encapsulated in exosomes. We aimed to explore the role of DANCR in BMMSC-Ex in immune tolerance after kidney transplantation and related mechanism. The isogenic/allograft kidney transplantation mouse model was established, and levels of serum creatinine (SCr) were determined. Hematoxylin-eosin staining was conducted to detect the inflammation, and immunohistochemistry was performed to detect the infiltration of CD4+ T cells. Levels of IFN-γ, IL-17, and IL-2 were examined by ELISA. Flow cytometry was conducted to determine Treg cells. In the allograft group, the inflammatory response was severe, CD4+ T cell infiltration, SCr levels, and plasma rejection-related factors were up-regulated, while injection of BMMSC-Ex reversed the results. BMMSC-Ex increased Treg cells in kidney transplantation mice. Interference with DANCR reversed the promoting effect of BMMSC-Ex on Treg cell differentiation. DANCR bound to SIRT1, promoted ubiquitination and accelerated its degradation. The injection of BMMSC-Ex (after interference with DANCR) promoted SIRT1 levels, inflammatory response, CD4+ T cell infiltration, SCr levels, and plasma rejection related factors' expression, while Treg cells were decreased. LncRNA DANCR in BMMSC-Ex promoted Treg cell differentiation and induced immune tolerance of kidney transplantation by down-regulating SIRT1 expression in CD4+ T cells.

Oxidative Stress Promotes Instability of Regulatory T Cells in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

We investigated the characteristics of regulatory T cells (Tregs), focusing on the relationship between their stability and reactive oxygen species (ROS), in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Intracellular expressions of effector cytokines, forkhead box protein 3 (FoxP3), ROS, phosphorylated mammalian target of rapamycin (mTOR), and sirtuin 1 (SIRT1) in Tregs from peripheral blood mononuclear cells (PBMCs) of patients with AAV and healthy controls (HC) were analyzed. The alterations in and functional ability of Tregs were compared before and after resveratrol (RVL) treatment of PBMCs in patients with AAV. Significantly higher expressions of interferon (IFN)-γ, interleukin (IL)-17, IL-4, ROS, and phosphorylated mTOR (pho-mTOR) and lower expression of SIRT1 in CD4+CD25+FoxP3+ cells were found in patients with AAV than in the HC. FoxP3 expression in CD4+CD25+ cells and suppressive function of Tregs were significantly lower in patients with AAV than in the HC. Tregs after RVL treatment demonstrated significant decreases in IFN-γ, ROS, and pho-mTOR levels and increases in FoxP3, SIRT1 levels, and functional activity. Conversely, the direct activation of SIRT1 by SRT1720 resulted in decreased FoxP3 expression, with no reduction in ROS levels. The pho-mTOR levels were significantly higher in Tregs after activation by SRT1720 than in those after RVL treatment. This study suggested that imbalanced changes in Tregs could be attributed to mTOR activation, in which ROS overproduction was predominantly implicated. Therefore, ROS is a key mediator for promoting Tregs instability in AAV.

Analysis of Expression of Different Histone Deacetylases in Autoimmune Thyroid Disease

CONTEXT

Histone deacetylases (HDACs) and histone acetyltransferases (HAT) have an important role in the regulation of gene transcription as well as in the development and function of CD4+Foxp3+ T regulatory (Treg) cells. Our group and others have reported that patients with autoimmune thyroid disease (AITD) show abnormalities in the levels and function of different Treg cell subsets.

OBJECTIVE

We aimed to analyze the levels of expression of several HDACs and the Tip60 HAT in the thyroid gland and immune cells from patients with AITD.

METHODS

The expression of HDAC1-11 and the Tip60 HAT, at RNA and protein levels, were determined in thyroid tissue from 20 patients with AITD and 10 healthy controls and these findings were correlated with clinical data. HDAC9 and Tip60 levels were also analyzed in thyroid cell cultures, stimulated or not with proinflammatory cytokines, as well as in different cell subsets from peripheral blood mononuclear cells.

RESULTS

Altered expression of different HDACs was observed in thyroid tissue from AITD patients, including a significant increase in HDAC9, at RNA and protein levels. Likewise, HDAC9 expression was increased in peripheral blood mononuclear cells particularly in Treg cells in patients with AITD. In contrast, Tip60 expression was reduced in thyroid gland samples from patients with Hashimoto thyroiditis.

CONCLUSION

Our results indicate that HDAC expression is dysregulated in thyroid gland and immune cells from patients with AITD, suggesting involvement in the pathogenesis of this condition.

5-Aza-2-deoxycytidine alleviates the progression of primary biliary cholangitis by suppressing the FoxP3 methylation and promoting the Treg/Th17 balance

Primary biliary cholangitis (PBC) is a common autoimmune liver disease manifested by the infiltration of CD4+ T cells, and the subsequent targeted injury of biliary epithelial cells (BECs). As important components of CD4 subsets, the Treg/Th17 axis maintains an immunological balance between self-tolerance and inflammation in the liver microenvironment. However, the role and regulatory mechanism of the Treg/Th17 axis in PBC remain unclear. In this study, we examined the Treg/Th17 axis in PBC patients and found that the Treg/Th17 axis was imbalanced in PBC at both the transcriptional and cellular levels, with Treg being a weak candidate, which correlates with the PBC progression. This imbalanced Treg/Th17 axis was likely to be affected by the FoxP3 hypermethylation, which was related to the increase of DNA methyltransferase. Furthermore, the effect of 5-Aza-2-deoxycytidine (DAC)-mediated FoxP3 demethylation on PBC mice was investigated. We verified that DAC significantly suppressed the FoxP3 methylation and rebuilt the Treg/Th17 balance, resulting in the alleviation of liver lesions and inflammation. Taken together, our data indicate that DAC plays a positive role in alleviating the progression of PBC through the inhibition of DNA methylation of FoxP3 to rebuild the balanced Treg/Th17 axis. DAC could be considered as a potential candidate for the development of new anti-inflammation strategies in the treatment of PBC.

The Anti-Inflammatory Effect of Zhibaidihuang Decoction on Recurrent Oral Ulcer with Sirt1 as the Key Regulatory Target

The syndrome of ROU is generally manifested as obvious pain, redness, and swelling of local ulceration area, accompanied by flushed face, red eyes, sore throat, and swollen gums. Traditional Chinese medicine (TCM) doctors believe that "yin deficiency" is one causative factor of ROU. Zhibaidihuang decoction (ZBDHD) is a prescriptively developed receipt, where Anemarrhena asphodeloides and Phellodendri amurensis Cortex are added in the original Liuweidihuang decoction. It is generally used for "yin deficiency" treatment. It can effectively reduce the recurrence of oral ulcers and release the severity of the disease. However, the mechanism of this activity remains to be elucidated. In this study, we found that ZBDHD has a certain therapeutic effect on the pathological changes of oral mucosa. Furthermore, the results of serum metabolomics showed ZBDHD influenced the synthesis and metabolism of certain fatty acids. The results of western blot, immunochemical, and immunofluorescence staining indicate that ZBDHD could increase the expression of Sirt1 and Foxp3 and suppress the expression and acetylation of NF-κB in oral mucosa cells. By screening active ingredients in ZBDHD, we found berberine, as well as other compounds, presenting high fitness of the Sirt1 reactive centre. Therefore, it is possible that ZBDHD can regulate the Sirt1-NF-κB pathway to improve fatty acids metabolism in the body, thereby achieving the effect of treating ROU.

Association of FOXP3 and GAGE10 promoter polymorphisms and decreased FOXP3 expression in regulatory T cells with susceptibility to generalized vitiligo in Gujarat population

Alterations in regulatory T (Treg) cells have been observed in generalized vitiligo (GV) patients and decreased Forkhead Box P3 (FOXP3) has been implicated in the disease pathogenesis. The present study examined FOXP3 rs3761547(A > G), rs3761548(C > A), rs2232365(A > G) and GAGE10 rs11798415(A > T) promoter single nucleotide polymorphisms (SNPs) in 419 GV patients and 429 controls from Gujarat population using PCR-RFLP and ARMS-PCR. Real-time PCR and flow cytometry were used for assessment of FOXP3 mRNA and protein levels respectively in 96 GV patients and 90 controls. The frequency of genotypes (p < 0.001) and alleles (p = 0.012 & p = 0.040) for rs3761547(A > G) and rs11798415(A > T) SNPs significantly differed between GV patients and controls. FOXP3 mRNA and protein levels were significantly decreased (p < 0.001) in GV Tregs compared to controls. Active vitiligo (AV) Tregs showed significantly reduced FOXP3 mRNA and protein levels compared to that of stable vitiligo (SV) (p = 0.02 & p = 0.039). The correlation of genotype-phenotype of FOXP3 SNPs suggested reduced FOXP3 mRNA (p = 0.019, p < 0.001 & p < 0.001) and protein (p = 0.028, p < 0.001 & p = 0.022) levels in patients with susceptible GG, AA and GG genotypes respectively. The GAGT, GCGT & ACGT haplotypes were prevalent in GV patients (p = 0.004, p = 0.004 & p = 0.016); however, GAGT & GCGT were overrepresented in patients with AV (p = 0.044 & p = 0.024). The susceptible GAGT and GCGT haplotypes in patients exhibited reduction in FOXP3 mRNA (p = 0.014 & p = 0.019) and protein (p = 0.024 & p = 0.028). DNA-protein docking analysis revealed reduced binding for transcription factor C/EBP to the susceptible allele 'G' (rs3761547) compared to A allele. For the first time, the study suggests significant association of FOXP3 rs3761547(A > G) & GAGE10 rs11798415(A > T) SNPs with susceptibility to GV in Gujarat population. In addition, the likely role of these SNPs in altered FOXP3 expression of Tregs may possibly affect Treg suppressive function in GV.

Dioscin alleviates hashimoto's thyroiditis by regulating the SUMOylation of IRF4 to promote CD4+CD25+Foxp3+ treg cell differentiation

Dioscin has been used as a treatment for Hashimoto's thyroiditis (HT) in China. However, the molecular mechanisms governing the modes of action of dioscin have not been elucidated. In this study, flow cytometry and Western blotting were used to identify the proportions of CD4⁺CD25⁺ regulatory T (Treg) cells and the expression of forkhead box P3 (Foxp3) and SUMO-specific protease 1 (SENP1) in HT patients' peripheral blood mononuclear cells (PBMCs). A pTg-induced rat model of HT was established by injection of 100 μg pTg. Then, the model rats were randomly divided into three groups (n = 5): control (NC), model (HT) and dioscin treatment. After oral administration of dioscin each day for two weeks, CD4⁺CD25⁺Foxp3⁺ Treg cells were analysed by flow cytometry, and the protein expression levels of SENP1, Foxp3, SUMO-1 and SUMO-2/3 were measured by Western blotting. Co-immunoprecipitation (Co-IP) was used to identify the SUMOylation of interferon regulatory factor 4 (IRF4). The results showed that the proportions of CD4⁺CD25⁺ Treg cells and the expression of Foxp3 were significantly decreased in HT patients, but the expression of SENP1 was enhanced compared to healthy controls (HCs). However, compared to the pTg-induced HT rat group, the expression of Foxp3, SUMO-1, and SUMO-2/3 and the proportions of CD4⁺CD25⁺Foxp3⁺ Treg cells were increased, whereas the expression of SENP1 was decreased, in the dioscin-treated group. Furthermore, the SUMOylation of IRF4 was increased after SENP1 was knocked down. The results of our study indicate that dioscin can promote the differentiation of the CD4⁺CD25⁺Foxp3⁺ Treg cells and subsequently upregulate the SUMOylation of IRF4 by downregulating SENP1 expression.

Genome-wide DNA methylation analysis of Hashimoto's thyroiditis during pregnancy

Hashimoto's thyroiditis (HT) during pregnancy is usually accompanied by an elevation of thyroid‐stimulating hormone and a reduction of serum‐free thyroxine during gestation, which may lead to abortion, preterm delivery, and reduced intellectual function of the offspring. Epigenetic alterations may provide important insights into genetic–environmental interactions in HT. Here, we examined global DNA methylation patterns in patients with HT during pregnancy. DNA was extracted from 13 women with HT during pregnancy (HTDP) and eight healthy pregnant women as a control group. Genome‐wide methylation was detected with the use of an Illumina Human Methylation 850K Beadchip. A total of 652 differentially methylated positions (DMPs) and 27 differentially methylated regions (DMRs) were identified between the HTDP and control groups. GO analysis revealed that DMPs were significantly enriched in 540 GO terms, which included regulation of the differentiation of keratinocytes, T helper cell differentiation, and alpha‐beta T‐cell differentiation. Moreover, significant enrichment of KEGG pathways of the DMPs included mucin‐type O‐glycan biosynthesis, focal adhesion, and the insulin signaling pathway. The GO items associated with DMRs included muscle cell proliferation, response to biotic stimulus, anatomical structure formation involved in morphogenesis, and genes primarily involved in the FoxO signaling pathway. Finally, the DTNA gene was identified as the seed gene of functional epigenetic modules. In summary, the DNA methylation pattern of the HTDP group was distinct from that of the control group, and thus, changes in DNA methylation may influence the development of HT by regulation of the autoimmunity process.

Clinicopathological characterization and prognostic implication of FOXP3 and CK19 expression in papillary thyroid carcinoma and concomitant Hashimoto's thyroiditis

Papillary thyroid carcinoma (PTC) is considered the most prevalent thyroid malignancy. The association between Hashimoto's thyroiditis (HT) and PTC is still unclear. We aimed to examine the clinicopathological impact of immunohistochemical staining of FOXP3 and Cytokeratin 19 in PTC and concomitant HT and their correlation with patients' outcome and survival. Eighty thyroid biopsies obtained from patients with PTC were immunostained by FOXP3 and CK19.The patients were treated by radioactive iodine (I131) and followed up. FOXP3 and CK19 expression were detected in 45% and 80% studied cases of PTC respectively. 16.7% of PTC with associated HT showed FOXP3+ lymphocytes in lymphocytic infiltrate of HT, while most of PTC associated HT express cytoplasmic CK19 positive Hurtle cells. FOXP3 was more expressed in PTC female patients more than 45 years with higher stage, lymph node, and distant metastasis, extracapsular extension, number of I131doses, and cumulative radioiodine doses with a highly statistically significant difference (p < 0.001). The relation was significant between CK19 immunostaining as regard 10-year Overall Survival and death (p value = 0.027 and 0.036, respectively). HT represents a step in the process of autoimmune inflammatory disease ending by the evolution of PTC with better prognosis, therefore appropriate follow up of these cases is needed. FOXP3 tends to be more expressed in PTC cases with worse prognostic variables and is predictable to become a recent prognostic and targeted therapy for PTC. There was a significant relation between CK19 immunostaining and 10 year overall survival.

The proportion of peripheral blood Tregs among the CD4+ T cells of autoimmune thyroid disease patients: a meta-analysis

Autoimmune thyroid disease (AITD) is characterized by a loss of self-tolerance to thyroid antigen. Tregs, whose proportions are controversial among CD4+ T cell from AITD patients (AITDs), are crucial in immune tolerance. Considering that drugs might affect Treg levels, we assumed that the differences originated from different treatment statuses. Thus, we performed a meta-analysis to explore proportions of Tregs in untreated and treated AITDs. PubMed, Embase and ISI Web of Knowledge were searched for relevant studies. Review Manager 5.3 and Stata 14.0 were used to conduct the meta-analysis. Subgroup analysis based on different diseases and cell surface markers was performed. Egger linear regression analysis was used to assess publication bias. Approximately 1,100 AITDs and healthy controls (HCs) from fourteen studies were included. Proportions of Tregs among CD4+ T cells of untreated AITDs were significantly lower than those in HCs (p = 0.002), but were not in treated patients (p = 0.40). Subgroup analysis revealed lower proportions of Tregs in untreated Graves' disease patients (GDs) (p = 0.001) but did not show obvious differences in untreated Hashimoto's thyroiditis patients (HTs) (p = 0.62). Furthermore, proportions of circulating FoxP3+ Tregs were reduced in untreated GDs (p < 0.00001) and HTs (p = 0.04). No publication bias was found. In this first meta-analysis exploring proportions of circulating Tregs among CD4+ T cells of AITDs with different treatment statuses, we found that Tregs potentially contribute to the pathogenesis of AITD but function differently in GD and HT. Remarkably, FoxP3+ Tregs, which were decreased in both diseases, might be promising targets for novel therapies.

Molecular Mechanisms Controlling Foxp3 Expression in Health and Autoimmunity: From Epigenetic to Post-translational Regulation

The discovery of the transcription factor Forkhead box-p3 (Foxp3) has shed fundamental insights into the understanding of the molecular determinants leading to generation and maintenance of T regulatory (Treg) cells, a cell population with a key immunoregulatory role. Work over the past few years has shown that fine-tuned transcriptional and epigenetic events are required to ensure stable expression of Foxp3 in Treg cells. The equilibrium between phenotypic plasticity and stability of Treg cells is controlled at the molecular level by networks of transcription factors that bind regulatory sequences, such as enhancers and promoters, to regulate Foxp3 expression. Recent reports have suggested that specific modifications of DNA and histones are required for the establishment of the chromatin structure in conventional CD4⁺ T (Tconv) cells for their future differentiation into the Treg cell lineage. In this review, we discuss the molecular events that control Foxp3 gene expression and address the associated alterations observed in human diseases. Also, we explore how Foxp3 influences the gene expression programs in Treg cells and how unique properties of Treg cell subsets are defined by other transcription factors.

The exploration of Hashimoto's Thyroiditis related miscarriage for better treatment modalities

Hashimoto's thyroiditis (HT) is the most prevalent autoimmune thyroid disease (ATD) worldwide and is strongly associated with miscarriage and even recurrent miscarriage (RM). Moreover, with a deepening understanding, emerging evidence has shown that immune dysfunctions caused by HT conditions, including imbalanced subsets of CD4+ T-helper cells, B regulatory (Breg) cells, high expression levels of CD56dim natural killer (NK) cells, and cytokines, possibly play an important role in impairing maternal tolerance to the fetus. In recent years, unprecedented progress has been made in recognizing the specific changes in immune cells and molecules in patients with HT, which will be helpful in exploring the mechanism of HT-related miscarriage. Based on these findings, research investigating some potentially more effective treatments, such as selenium (Se), vitamin D3, and intravenous immunoglobulin (IVIG), has been well developed over the past few years. In this review, we highlight some of the latest advances in the possible immunological pathogenesis of HT-related miscarriage and focus on the efficacies of treatments that have been widely introduced to clinical trials or practice described in the most recent literature.

MiR-23a-3p-regulated abnormal acetylation of FOXP3 induces regulatory T cell function defect in Graves’ disease

This study aims to investigate the mechanism of miR-23a-3p in regulating Treg dysfunction in Graves’ disease (GD). The percentage of Treg cells and interleukin (IL)-17+ T cells were determined by flow cytometry. The expression of forkhead box P3 (FOXP3), sirtuin 1 (SIRT1), RAR-related orphan receptor gamma t (RORγt) and miR-23a-3p was analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) or Western blot. CD4+ T cells were treated with SIRT1 specific inhibitor EX-527 or left untreated. MiR-23a-3p mimic or inhibitor were transfected into CD4+ T cells. Acetylation expression of FOXP3 was analyzed by immunoprecipitation. The suppressive function of Treg was analyzed by the carboxyfluorescein succinimidyl ester (CFSE) assay. The results showed that GD patients have significantly less Treg cells and more IL-17+ T cells. FOXP3 and miR-23a-3p were significantly down-regulated meanwhile SIRT1 and RORγt were up-regulated in GD patients. FOXP3 acetylation level of the GD group was lower than that of control groups. After EX-527 treatment, the percentage of Treg cells, expression and acetylation level of FOXP3 were significantly increased in the GD group. GD Tregs exhibited weaker suppressive activity, miR-23a-3p mimic suppressed SIRT1 expression and suppressive-activity of Tregs whereas it promoted the expression and acetylation level of FOXP3 in the GD group. Our findings suggest that the Treg function defect in GD patients is mediated by the abnormal acetylation of FOXP3, which is regulated by miR-23a-3p via targeting SIRT1.