Implication of VDR Rs7975232 and FCGR2A Rs1801274 Gene Polymorphisms in the Risk and the Prognosis of autoimmune Thyroid Diseases in the Tunisian Population.

Hashimoto's thyroiditis (HT) and Graves' disease (GD) are autoimmune thyroid diseases (AITD) that cause hypothyroidism and hyperthyroidism, respectively. The vitamin D receptor (VDR) and the Fey receptor IIA (FcγRIIA), are implicated in the etiology of AITD. This study was conducted to examine the implication of VDR rs7975232 and FCGR2A rs 1801274 variations in the susceptibility and the prognosis of AITD in the Tunisian population. The rs7975232 and rs1801274 (R131H) polymorphisms were analyzed in 162 controls and 162 AITD patients (106 HT and 56 GD) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and amplification of refractory mutation system-PCR (ARMS-PCR), respectively. No significant difference was demonstrated for the rs7975232 between patients and controls. However, a significant association was shown between the rs1801274 polymorphism and AITD or HT in the dominant (p = 0.03 or p = 0.01), codominant (p = 0.019 or p = 0.026) and allelic (p = 0.011 or p = 0.012) models. The rs7975232 was associated with the absence or the presence of anti-thyroglobulin antibody, with the age of AITD and GD patients during the first diagnosis (p = 0.01 and p = 0.009, respectively) and with a high T4 level at the beginning of HT disease. However, the FCGR2A gene polymorphism was associated with a low T4 level at the beginning of GD disease. In conclusion, this study indicates that only the FCGR2A variation could be related to AITD and HT susceptibility and that VDR and FCGR2A gene variations constitute factors to prognosticate the severity of AITD, HT and GD.

Association Between Polymorphisms of IL-23/IL-17 Pathway and Clinical Phenotypes of Autoimmune Thyroid Diseases.

BACKGROUND: Several autoimmune and inflammatory disorders, including autoimmune thyroid diseases (AITD), have been linked to Th17 cells and the IL-23/IL-17 axis. Current data suggest that genetic variation contributes greatly to disease susceptibility to AITD. OBJECTIVES: To study the role of single nucleotide polymorphisms (SNPs) of IL-23/IL-17 pathway in AITD predisposition and test the gene-gene/gene-sex interactions in these loci. METHODS: A total of 1051 patients with AITD, including 657 patients with Graves' disease (GD) and 394 patients with Hashimoto's thyroiditis (HT), and 874 healthy controls were enrolled in this case-control association study. Six SNPs were selected and genotyped by multiplex PCR combined with high-throughput sequencing. Interactions were tested by the general multifactor dimensionality reduction (GMDR) method. RESULTS: Allele C and combinational genotype AC+CC of rs3212227 within IL-23 were significantly associated with GD with goiter (p=0.003 and 0.014, respectively). Allele G and combinational genotype AG+GG of rs4819554 within IL-17RA were significantly related to HT with family history and the severity of HT (p=0.011 and 0.027; p=0.041 and 0.035). Also, allele T and genotype CT+TT of rs9463772 within IL-17F were significantly correlated with the severity of HT (p=0.001 and 0.027, respectively). Moreover, high dimensional gene-sex interaction (IL-23R-IL-23-IL-17RA-IL-17F-sex) was identified in AITD, GD, and HT patients with GMDR analysis. CONCLUSIONS: Our study identified the novel loci and gene-sex interaction in AITD. This evidence, from another perspective, suggests that sex, IL-23/IL-17 pathway, and Th17 cells play an important role in the pathogenesis of AITD.

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.

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.

Dysregulated Antibody, Natural Killer Cell and Immune Mediator Profiles in Autoimmune Thyroid Diseases.

The pathogenesis of autoimmune thyroid diseases (AITD) is poorly understood and the association between different immune features and the germline variants involved in AITD are yet unclear. We previously observed systemic depletion of IgG core fucosylation and antennary α1,2 fucosylation in peripheral blood mononuclear cells in AITD, correlated with anti-thyroid peroxidase antibody (TPOAb) levels. Fucose depletion is known to potentiate strong antibody-mediated NK cell activation and enhanced target antigen-expressing cell killing. In autoimmunity, this may translate to autoantibody-mediated immune cell recruitment and attack of self-antigen expressing normal tissues. Hence, we investigated the crosstalk between immune cell traits, secreted proteins, genetic variants and the glycosylation patterns of serum IgG, in a multi-omic and cross-sectional study of 622 individuals from the TwinsUK cohort, 172 of whom were diagnosed with AITD. We observed associations between two genetic variants (rs505922 and rs687621), AITD status, the secretion of Desmoglein-2 protein, and the profile of two IgG N-glycan traits in AITD, but further studies need to be performed to better understand their crosstalk in AITD. On the other side, enhanced afucosylated IgG was positively associated with activatory CD335- CD314+ CD158b+ NK cell subsets. Increased levels of the apoptosis and inflammation markers Caspase-2 and Interleukin-1α positively associated with AITD. Two genetic variants associated with AITD, rs1521 and rs3094228, were also associated with altered expression of the thyrocyte-expressed ligands known to recognize the NK cell immunoreceptors CD314 and CD158b. Our analyses reveal a combination of heightened Fc-active IgG antibodies, effector cells, cytokines and apoptotic signals in AITD, and AITD genetic variants associated with altered expression of thyrocyte-expressed ligands to NK cell immunoreceptors. Together, TPOAb responses, dysregulated immune features, germline variants associated with immunoactivity profiles, are consistent with a positive autoreactive antibody-dependent NK cell-mediated immune response likely drawn to the thyroid gland in AITD.

Polymorphisms in MIR499A and MIR125A gene are associated with autoimmune thyroid diseases.

BACKGROUND: Single nucleotide polymorphisms (SNPs) of the miR-146a, miR-499a and miR-125a have been shown to be associated with the susceptibility to several autoimmune diseases. This study was conducted to identify the association of SNPs rs2910164, rs57095329, rs3746444 and rs12976445 with autoimmune thyroid diseases (AITDs) in a Chinese Han population. METHODS: We enrolled 1061 patients with AITDs, including 701 patients with Graves' disease (GD) and 360 patients with Hashimoto's thyroiditis (HT), and 938 healthy individuals for a case-control genetic association study. Four SNPs were selected for genotyping by multiplex polymerase chain reaction and ligase detection reaction. RESULTS: The frequencies of rs3746444 genotypes in patients with AITD and GD differed significantly from those in the controls. The frequencies of rs12976445 genotypes in patients with HT differed significantly from those in the controls. The frequencies of allele C in HT groups were significantly higher than those in control group. For the rs3746444 polymorphism, genetic associations between the combinational genotype and AITD/GD risk were observed in the dominant model, recessive model, and overdominant model. For the rs12976445 polymorphism, genetic associations between the combinational genotype and HT risk were also found in the dominant model and overdominant model. Moreover, gene-sex interactions were identified by GMDR and 2 × 2 crossover analysis. CONCLUSIONS: Our results suggest rs3746444 (miR-499a) and rs12976445 (miR-125a) associated with AITD susceptibility and potential gene-sex interactions between the four polymorphisms and AITD.