Polymorphisms in Th17-related genes and the pathogenesis of autoimmune thyroid disease.

The prognosis of autoimmune thyroid disease (AITD) including Graves' disease (GD) and Hashimoto's disease (HD) is difficult to predict. We previously suggested that Th17 cells may be associated with the pathogenesis of AITD. However, the association between gene polymorphisms in Th17-related genes and the prognosis of AITD was not clarified. To clarify this association, we genotyped 12 polymorphisms in 11 Th17-related genes (IL1Ra, IL6R, IL17R, IL21R, IL23R, CCR6, SOCS3, RORC, IL17A, IL17F and IL21) in 142 HD patients including 58 patients with severe HD and 48 patients with mild HD, 170 patients with GD including 81 patients with intractable GD and 49 patients with GD in remission, and 84 healthy volunteers. The frequency of the IL17F rs763780 T allele was higher in patients with severe HD than in patients with mild HD (p = .008). The frequency of the IL17R rs9606615 T allele was higher in patients with HD than in normal subjects (p = .011). The frequencies of the SOCS3 rs4969170 AA genotype, CCR6 rs3093024 AA genotype, and IL21 rs907715 AA genotype were higher in patients with intractable GD than in patients with GD in remission (p = .035, p = .002 and p = .030, respectively). In conclusion, IL17R rs9607715 and IL17F rs763780 polymorphisms are associated with the susceptibility and severity of HD, respectively. IL21 rs907715, SOCS3 rs4969170 and CCR6 rs3093024 polymorphisms are associated with the intractability of GD.

Functional Polymorphisms of the Type 1 and Type 2 Iodothyronine Deiodinase Genes in Autoimmune Thyroid Diseases.

Graves' disease (GD) and Hashimoto's disease (HD) are major autoimmune thyroid diseases (AITDs), and their pathological conditions vary among patients. Type 1 iodothyronine deiodinase (D1) and type 2 iodothyronine deiodinase (D2) convert from thyroxine (T4) to triiodothyronine (T3). However, few findings have been described concerning the association between polymorphisms in D1 and D2 genes and AITD. Therefore, we genotyped D1 rs11206244, D2 rs225014, and rs12885300 polymorphisms in 134 GD patients, including 54 patients with intractable GD and 44 patients with GD in remission and 132 HD patients, including 57 patients with severe HD, 45 patients with mild HD, and 84 healthy controls using PCR-RFLP. In the D2 rs225014 polymorphism, the TT genotype, which was correlated with higher D2 activity, was less frequent in AITD, especially in HD, than in control subjects (P = 0.0032 and 0.0002, respectively). Moreover, they were also less frequent in HD than in GD (P = 0.0199). The TT genotype and T allele were less frequent in severe HD and mild HD than in control subjects (P = 0.0003, 0.0006, 0.0432, and 0.0427, respectively). In conclusion, the low frequency of the TT genotype D2 rs225014 polymorphism was associated with the development of AITD and severity of HD.

Association of IL-10-Regulating MicroRNAs in Peripheral Blood Mononuclear Cells with the Pathogenesis of Autoimmune Thyroid Disease.

Interleukin (IL)-10 is known to suppress inflammation in autoimmune diseases. IL-10 can be regulated by miRNAs. To elucidate the involvement of miRNAs that regulate IL-10 expression with the pathogenesis of autoimmune thyroid disease (AITD), we examined the expression levels of hsa-miR-27a-3p, hsa-miR-98-5p, hsa-miR-106a-5p, and hsa-miR-223-3p in peripheral blood mononuclear cells (PBMCs) from 43 patients with Graves' disease (GD), 38 patients with Hashimoto's disease (HD), and 21 healthy volunteers. We evaluated the association between the expression levels of four miRNAs and intracellular expression of IL-10 in PBMCs from 11 healthy volunteers. We also genotyped MIR27A rs895819 G/A and MIR106A rs3747440 C/G polymorphisms, which may be related to the expression of these miRNAs in 141 patients with GD, 178 patients with HD, and 84 healthy volunteers. The expression level of hsa-miR-106a-5p was significantly higher in patients with intractable GD than in those with GD in remission (p = 0.0113). The expression level of hsa-miR-223-3p was significantly lower in GD than in HD and lower in patients with intractable GD than in healthy volunteers (p = 0.0094, 0.0340). We found a negative correlation between the expression levels of hsa-miR-98-5p and the proportions of IL-10+ cells in stimulated PBMCs from healthy volunteers (p = 0.0092). The G allele of the MIR27A polymorphism was significantly more frequent in patients with mild HD than in healthy volunteers (p = 0.0432). In conclusion, the expression levels of hsa-miR-106a-5p and hsa-miR-223-3p were associated with the pathogenesis of AITDs. hsa-miR-98-5p may negatively regulate the expression of IL-10. The functional polymorphism of MIR27A was associated with HD severity.

Polymorphisms and expression of toll-like receptors in autoimmune thyroid diseases.

Graves' disease (GD) and Hashimoto's disease (HD) are autoimmune thyroid diseases (AITDs). Prognosis of AITDs varies in each patient. Toll-like receptors (TLRs) are pattern-recognition receptors that activate signaling pathways involved in the production of proinflammatory cytokines. UNC93B1 is a transcription factor of TLR7 and TLR9. In this study, we examined the association of TLR expression and TLR and UNC93B1 polymorphisms with the development and prognosis of AITDs. The ratio of intracellular TLR7 (iTLR7) and iTLR9 intensities in B cells was lower in patients with GD in remission than in patients with intractable GD (p = 0.0007). The frequency of G allele of TLR7 rs3853839 G/C polymorphism was significantly higher in male patients with GD and intractable GD than in control subjects (p = 0.0062 and 0.0173, respectively). The frequencies of T allele of TLR9 rs187084 C/T polymorphism and C allele of TLR9 rs352140 C/T polymorphism were significantly higher in patients with intractable GD who had GG genotype of TLR7 rs3853839 polymorphism, which is associated with higher TLR7 expression, than in patients with GD in remission (p = 0.0334 and 0.0023, respectively). The frequencies of AA genotype and A allele of UNC93B1 rs308328 polymorphism were significantly higher in patients with GD than in patients with HD (p = 0.0406 and 0.0316, respectively). These results suggested that the ratio of iTLR7 and iTLR9 intensities was associated with the development and intractability of GD and that TLR7 and UNC93B1 polymorphisms were associated with the development of GD.

Involvement of genes encoding apoptosis regulatory factors (FAS, FASL, TRAIL, BCL2, TNFR1 and TNFR2) in the pathogenesis of autoimmune thyroid diseases.

Apoptosis is necessary for the maintenance of self-tolerance by eliminating autoreactive immune cells in the periphery. To clarify the association between the pathogenesis of autoimmune thyroid disease (AITD) and genes encoding apoptosis regulatory factors, we genotyped the FAS -1377G/A, -670A/G, FASL -844C/T, TRAIL -716C/T, BCL2 -938C/A, +127G/A, TNFR1 -383A/C and TNFR2 +676T/G polymorphisms. The frequencies of the FASL -844CC and BCL2 -938AA genotypes were significantly lower in AITD patients than in control subjects (P=0.0101 and 0.0307, respectively). The frequency of the TNFR2 +676TT genotype was significantly lower in Graves' disease (GD) patients than in controls (P=0.0284). The serum sFasL level was significantly higher in GD and Hashimoto's disease (HD) patients than in control subjects (P=0.0003 and 0.0017, respectively). The serum sFasL levels in control subjects were significantly lower than those in intractable GD, GD in remission, and HD without treatment (P=0.0310, 0.0007 and 0.0002, respectively). The serum sFasL levels in HD with treatment were significantly lower than those in HD without treatment (P=0.0490). The polymorphisms in genes encoding apoptosis regulatory factors (FASL, BCL2) and serum levels of sFasL may be associated with immune dysregulation.

Association of the polymorphisms of chemokine genes (IL8, RANTES, MIG, IP10, MCP1 and IL16) with the pathogenesis of autoimmune thyroid diseases.

Chemokines induce leukocyte chemotaxis and contribute to chronic inflammation. To clarify the association between functional polymorphisms in genes encoding some chemokines and the pathogenesis of Autoimmune thyroid disease (AITD), we genotyped IL8 -251T/A, Regulated upon Activation, Normal T cell Expressed and presumably Secreted (RANTES) - 403G/A, -28C/G, MIG rs2276886G/A, IP10 -1596C/T, Monocyte Chemoattractant Protein1 (MCP1) - 2518G/A and IL16 -295T/C polymorphisms. We genotyped these polymorphisms using the PCR-RFLP method in 149 Graves' disease (GD) patients, including 59 patients with intractable GD and 53 patients with GD in remission, as well as 131 Hashimoto's disease (HD) patients, including 54 patients with severe HD, 46 patients with mild HD and 99 healthy controls. The IL8 -251TT genotype and MIG rs2276886 A allele were more frequent in patients with AITD (p = 0.0139 and p = 0.0005, respectively). The RANTES - 403AA and -28GG genotypes were less frequent in patients with AITD (p = 0.0164 and p = 0.0221, respectively). The MCP1 -2518GG genotype was more frequent in HD patients (p = 0.0323). The MIG rs2276886 AG genotype was less frequent in patients with intractable GD (p = 0.0051). Interestingly, the age of onset in GD patients with the RANTES - 28CC genotype was younger than in those with -28CG and GG genotypes (p = 0.0028). In this study, we first reported that the polymorphisms in IL8, RANTES and MIG genes are associated with the development of AITD, and that the MIG rs2276886 AG genotype is associated with the intractability of GD. The RANTES - 28CC genotype is associated with young onset of GD.

Increases of microRNA let-7e in peripheral blood mononuclear cells in Hashimoto's disease.

MicroRNA (miRNA) is a family of non-coding RNAs that have important roles in various vital functions. It has been reported that let-7e, a miRNA, may be involved in the regulation of interleukin (IL)-10 production. The purpose of this study was to evaluate the role of let-7e as a regulator of IL-10 production in the pathological processes of autoimmune thyroid diseases (AITDs). We evaluated the association between let-7e expression and intracellular expression of IL-10 in the peripheral blood mononuclear cells (PBMCs) collected from 11 healthy volunteers. Then we investigated the expression levels of let-7e in the PBMCs of 50 patients with Graves' disease (GD), 42 patients with Hashimoto's disease (HD) and 28 healthy controls. We found negative correlations between the expression level of let-7e and IL-10 messengerRNA (mRNA) and between the expression level of let-7e and proportion of IL-10(+) cells in stimulated PBMCs from healthy volunteers (r = -0.44, p = 0.0267 and r = -0.49, p = 0.0166, respectively). The expression levels of let-7e were significantly increased in HD patients compared with those in GD patients and healthy volunteers (p = 0.0003 and p = 0.0011, respectively). let-7e may be associated with the pathogenesis of HD through the regulation of intracellular IL-10 expression.