Association of IRF8 gene polymorphisms with autoimmune thyroid disease

Associations of serum keratin 1 with thyroid function and immunity in Graves' disease

BACKGROUND

Autoimmune thyroid disease (AITD) can cause enormous health burdens; however, trustworthy biomarkers in identifying the onset and progression of AITD are limited. In this study, we attempted to discover new potential serum biomarkers to discriminate AITD using mass spectrometry (MS).

METHODS

In the biomarker study cohort, 20 patients with Graves' disease (GD), 20 patients with Hashimoto's thyroiditis (HT), and 20 healthy controls were enrolled for a liquid chromatographic-tandem MS assessment. A novel biomarker, keratin 1 (KRT1), was selected for further evaluation in the validation cohort, including 125 patients with GD, 34 patients with HT, and 77 controls. Relationships of serum KRT1 with AITD-related immunomodulatory cytokines were also analyzed using enzyme-linked immunosorbent assays (ELISAs).

RESULTS

In the MS analysis, KRT1 was the single marker overexpressed in GD, while it was underexpressed in HT. In the ELISA analysis of the validation cohort, KRT1 was consistently upregulated in GD, while it was not downregulated in HT. There were significant associations of KRT1 levels with thyroid function in GD, AITD, and overall subjects. Additionally, a significant association of KRT1 levels with thyroid-stimulating hormone receptor antibody (TSHRAb) levels was observed. Moreover, there were significant associations of KRT1 with osteopontin (OPN) and B-cell activating factor (BAFF) levels in GD.

CONCLUSIONS

Serum KRT1 levels were upregulated in GD and were associated with thyroid function and TSHRAb levels. Moreover, KRT1 was correlated with the BAFF and OPN levels in GD patients. Further molecular-based research to elucidate the role of KRT1 in the pathogenesis of AITD is needed.

IRF8: Mechanism of Action and Health Implications

Interferon regulatory factor 8 (IRF8) is a transcription factor of the IRF protein family. IRF8 was originally identified as an essentialfactor for myeloid cell lineage commitment and differentiation. Deletion of Irf8 leads to massive accumulation of CD11b⁺Gr1⁺ immature myeloid cells (IMCs), particularly the CD11b⁺Ly6C^hi/+Ly6G⁻ polymorphonuclear myeloid-derived suppressor cell-like cells (PMN-MDSCs). Under pathological conditions such as cancer, Irf8 is silenced by its promoter DNA hypermethylation, resulting in accumulation of PMN-MDSCs and CD11b⁺ Ly6G⁺Ly6C^lo monocytic MDSCs (M-MDSCs) in mice. IRF8 is often silenced in MDSCs in human cancer patients. MDSCs are heterogeneous populations of immune suppressive cells that suppress T and NK cell activity to promote tumor immune evasion and produce growth factors to exert direct tumor-promoting activity. Emerging experimental data reveals that IRF8 is also expressed in non-hematopoietic cells. Epithelial cell-expressed IRF8 regulates apoptosis and represses Osteopontin (OPN). Human tumor cells may use the IRF8 promoter DNA methylation as a mechanism to repress IRF8 expression to advance cancer through acquiring apoptosis resistance and OPN up-regulation. Elevated OPN engages CD44 to suppress T cell activation and promote tumor cell stemness to advance cancer. IRF8 thus is a transcription factor that regulates both the immune and non-immune components in human health and diseases.

Serum interferon levels associated with the disease activity in women with overt Graves' disease

BACKGROUND

Inflammatory cytokines participate in immune reactions and the pathogenesis of autoimmunity. Herein, we quantified four groups of inflammatory cytokines, including interferons (IFNs), the tumor necrosis factor (TNF) superfamily (TNFSF), interleukin (IL)-related cytokines, and bone and extracellular matrix remodeling-related cytokines to determine their contributions in women with overt Graves' disease (GD).

METHODS

Forty-three women with GD were enrolled in this cross-sectional study. Thirty-seven cytokines, thyroid-stimulating hormone (TSH), free thyroxine, and TSH receptor antibody (TSHRAb) were quantified. GD patients with a low TSH level at the time of sample collection were defined as having active GD.

RESULTS

Patients with active GD had higher IFN-α2, IFN-γ, IFN-λ1, and IFN-λ2 levels than those with inactive GD. In addition, certain TNFSF cytokines, including soluble cluster of differentiation 30 (sCD30), TNFSF member 14 (TNFSF14), pentraxin (PTX)-3, soluble TNF receptor 2 (sTNF-R2), and thymic stromal lymphopoietin (TSLP) were higher in active GD than in inactive GD. Moreover, active GD patients had higher IL-2, IL-12(p40), osteocalcin (OCN), and matrix metalloproteinase (MMP)-3 than inactive GD patients. All IFNs except IFN-λ1 were correlated with TSHRAb titers. Moreover, TNFSF cytokines, consisting of B-cell-activating factor, sCD30, TNFSF14, PTX-3, sTNF-R2, and TSLP, were associated with TSHRAb levels.

CONCLUSIONS

Serum IFNs could be the most remarkable cytokines in modulating the disease severity and TSHRAb titers in women with full-blown GD. Further molecular-based research to clarify the actual role of IFNs in the disease progression of GD is needed.

Simultaneous measurement of twenty-nine circulating cytokines and growth factors in female patients with overt autoimmune thyroid diseases

Cytokines and growth factors participate in immune responses, and the pathogenesis of autoimmune diseases. Herein, we simultaneously examined differential levels of 29 circulating factors to determine their associations in female patients with overt autoimmune thyroid disease (AITD). We enrolled 40 patients with Graves' disease (GD), 20 patients with Hashimoto's thyroiditis (HT), and 14 healthy controls. Twenty-nine circulating factors were simultaneously measured. GD patients with low thyroid-stimulating hormone at the time of sample collection were defined as having active GD. B-cell activating factor (BAFF) levels were associated with GD and HT (p = .001 and .001, respectively) and interferon (IFN)-α levels were higher in the HT group than in the control group (p = .021). Significant associations of serum BAFF and tumour necrosis factor (TNF)-α levels with free thyroxin (FT4) were present in HT (r = -0.498, p = .026, and r = 0.544, p = .013, respectively). Meanwhile, there were significant associations of FT4 with interleukin (IL)-4 and eotaxin levels in GD (r = 0.354, p = .025 and r = 0.384, p = .014, respectively). In active GD, serum BAFF and eotaxin level were correlated with FT4 levels (r = 0.465, p = .034, and r = 0.463, p = .035, respectively). In conclusion, BAFF is the best circulating indicator to identify GD and HT among all chosen 29 biomarkers, and it could be used to predict the disease severity in HT and active GD. Meanwhile, IFN-α could be another reliable parameter for recognising HT.

Genome-Wide Analysis Identifies Two Susceptibility Loci for Positive Thyroid Peroxidase and Thyroglobulin Antibodies

INTRODUCTION

Thyroid peroxidase (TPO) and thyroglobulin (Tg) are main components of the thyroid gland and play an essential role in thyroid hormone synthesis. The development of antibodies to thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) is the major diagnostic hallmark and early indicator of autoimmune thyroid disease. TPOAb and TgAb are under strong genetic influence; however, genetic factors that determine thyroid antibody positivity are largely unknown.

MATERIALS AND METHODS

To identify novel loci associated with TPOAb and/or TgAb positivity, we performed a genome-wide meta-analysis in a total of 2613 individuals from Croatia. Participants with elevated plasma TPOAb and/or TgAb were defined as cases (N = 619) and those with TPOAb and TgAb within reference values were defined as controls (N = 1994).

RESULTS

We identified 2 novel loci, of which 1 is located within the YES1 gene (rs77284350, P = 1.50 × 10-8), and the other resides within the IRF8 gene (rs16939945, P = 5.04 × 10-8).

CONCLUSIONS

Although the observed variants were associated with TPOAb and TgAb positivity for the first time, both YES1 and IRF8 were previously linked to susceptibility to other autoimmune diseases, and represent plausible biological candidates. This study adds to the knowledge of genetics underlying thyroid antibodies and provides a good basis for further research.

Associations of gene polymorphisms in interferon-alpha signature-related genes with autoimmune thyroid diseases

Interferon (IFN)-α treatment predisposes patients to the occurrence of autoimmune thyroid disease (AITD).

METHODS

We investigated associations of single nucleotide polymorphisms (SNPs) of molecules participating in the IFN-α signature, including rs2304204 and rs2304206 of IFN regulatory factor 3 (IRF3), rs1061501 of IRF7, and rs7708392 of TNFA1P3-interacting protein 1 with serum IFN-α levels and AITD in an ethnic Chinese (ie Taiwanese) population. Totally, 319 patients with Graves' disease (GD), 83 patients with Hashimoto's thyroiditis (HT) and 351 healthy controls were recruited.

RESULTS

There were increased percentages of the C allele, and CC and TC + CC genotypes of rs1061501 in GD patients compared to the controls. HT patients had higher serum IFN-α levels compared to the controls, while there was no difference in serum IFN-α levels between patients with GD and controls. However, patients with GD in a remission status had lower serum IFN-α levels than those without remission. On the other hand, the C allele of rs1061501 was only associated with serum IFN-α levels in patients with HT.

CONCLUSIONS

The SNP rs1061501 of IRF7 was associated with the development of GD. Serum IFN-α levels were associated with HT, while they might modify the disease status of GD. Moreover, a genetic effect of rs1061501 on regulating serum IFN-α production was observed in HT.

Synchronized expressions of serum osteopontin and B cell-activating factor in autoimmune thyroid disease

BACKGROUND

Osteopontin (OPN) is recognized as a potent immunoregulator of autoimmune disease. In the study, we tried to explore the association of serum OPN levels with autoimmune thyroid disease, including Graves' disease (GD) and Hashimoto's thyroiditis (HT), in an ethnic Chinese population.

MATERIALS AND METHODS

We enrolled 131 patients with GD, 33 patients with HT and 123 healthy controls. Serum OPN, B cell-activating factor (BAFF) and interferon (IFN)-α levels were quantified. Graves' disease patients with high thyroid function at the time of sample collection were defined as having active GD, while the other patients were defined as having inactive GD.

RESULTS

Serum OPN levels were higher in active GD than in inactive GD and the control groups (P = 0.001 and P = 0.018, respectively). In GD, significant associations of OPN levels with thyroid-stimulating hormone receptor antibody (TSHRAb) levels were observed in women (r = -0.344, P = 0.002, and r = 0.440, P = 0.004, respectively) but not in men. Osteopontin levels were associated with BAFF levels only in women with GD or HT (r = 0.506, P < 0.001 and r = 0.430, P = 0.025, respectively), but not in men with GD or HT.

CONCLUSIONS

Serum OPN levels were upregulated in active GD, and serum OPN levels were associated with thyroid function and TSHRAb levels in GD. Additionally, OPN levels were correlated with BAFF levels in GD and HT. The associations of OPN levels with clinical phenotypes of GD and BAFF levels showed a dimorphic pattern.

Ankylosing spondylitis is associated with aberrant DNA methylation of IFN regulatory factor 8 gene promoter region

OBJECTIVES

To investigate the role of methylation levels of the IFN regulatory factor 8 (IRF8) gene promoter in the development of ankylosing spondylitis (AS).

METHODS

In this study, we compared the methylation levels of the IRF8 gene promoter between 99 AS patients and 99 healthy controls using MethylTarget approach. Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) was performed to compare the mRNA levels of the IRF8 gene in the other 19 AS patients and 19 healthy controls.

RESULTS

Differential methylation was found in 91 CpG sites of the IRF8 gene promoter, and 4 CpG regions were highly methylated in AS patients compared to healthy controls (p < 0.05). In the verification stage, we found that the mRNA levels of the IRF8 gene in AS patients were significantly lower than that in controls (AS 0.77 (0.39-1.74), P = 0.038). Positive correlations between methylation of the IRF8 gene and the duration of disease, BASFI, and ESR were observed in AS patients.

CONCLUSIONS

We found a significant hypermethylation of the IRF8 gene promoter and a downregulation of the mRNA levels of the IRF8 gene in AS patients. This suggests that aberrant methylation of the IRF8 gene promoter may probably contribute to the development and pathogenesis of AS through regulating the expression of mRNA.

Associations of secreted phosphoprotein 1 and B lymphocyte kinase gene polymorphisms with autoimmune thyroid disease

BACKGROUND

Dysregulation of the type 1 interferon (IFN)-related signalling pathway predisposes one to autoimmune diseases. Possible associations of single-nucleotide polymorphisms (SNPs) of secreted phosphoprotein 1 (SPP1) and B lymphocyte kinase (BLK) of the type 1 IFN-related signalling pathway with autoimmune thyroid disease (AITD) in an ethnic Chinese (ie Taiwanese) population were tested.

METHODS

Totally, 83 Hashimoto's thyroiditis (HT) patients, 319 Graves' disease (GD) patients and 369 controls were enrolled. Genotypes of the two SNPs (rs1126772 and rs1126616) of SPP1 and two SNPs (rs13277113 and rs2736340) of BLK were determined.

RESULTS

Our results showed reduced percentages of the G allele of rs13277113 of BLK in GD (P = 0.037, odds ratio [OR] = 0.78, 95% confidence interval [CI] = 0.62-0.99) and HT (P = 0.002, OR = 0.54, 95% CI = 0.36-0.81), compared to the controls. At the same time, lower frequencies of the C allele of rs2736340 of BLK in GD (P = 0.025, OR = 0.76, 95% CI = 0.60-0.97) and HT (P = 0.003, OR = 0.53, 95% CI = 0.35-0.81) than the controls were also observed. There were significantly higher AT haplotype frequencies of rs1327713 and rs2736340 in GD and HT patients than in the controls (P = 0.025, OR = 1.31, 95% CI = 1.03-1.67, and P = 0.003, OR = 1.89, 95% CI = 1.24-2.87, respectively). Moreover, the anti-microsomal antibody titre was associated with rs2736340.

CONCLUSIONS

Genetic variants of rs13277113 and rs2736340 of BLK were associated with susceptibility to GD, HT and AITD in an ethnic Chinese population. Our results suggest the BLK may participate in the pathogenesis of GD, HT and AITD.

Exploring immunomodulation by endocrine changes in Lady Windermere syndrome

Lung disease due to nontuberculous mycobacteria (NTM) occurs with disproportionate frequency in postmenopausal women with a unique phenotype and without clinically apparent predisposing factors. Dubbed 'Lady Windermere syndrome', the phenotype includes low body mass index (BMI), tall stature and higher than normal prevalence of scoliosis, pectus excavatum and mitral valve prolapse. Although the pathomechanism for susceptibility to NTM lung disease in these patients remains uncertain, it is likely to be multi-factorial. A role for the immunomodulatory consequences of oestrogen deficiency and altered adipokine production has been postulated. Altered levels of adipokines and dehydroepiandrosterone have been demonstrated in patients with NTM lung disease. Case reports of NTM lung disease in patients with hypopituitarism support the possibility that altered endocrine function influences disease susceptibility. This paper catalogues the evidence for immunomodulatory consequences of predicted endocrine changes in Lady Windermere syndrome, with emphasis on the immune response to NTM. Collectively, the data warrant further exploration of an endocrine link to disease susceptibility in Lady Windermere syndrome.

IRF7 Gene Variations Confer Susceptibility to Autoimmune Thyroid Diseases and Graves' Ophthalmopathy

The objective of this study was to investigate whether IRF7 polymorphisms are associated with autoimmune thyroid diseases (AITDs). We selected three single nucleotide polymorphisms (SNPs) of IRF7, namely, rs1061501, rs1131665, and rs1061502 for genotyping using PCR-based ligase detection reaction (LDR) method in a total of 1659 participants (592 with Graves' disease, 297 with Hashimoto's thyroiditis, and 770 healthy controls). Gene-disease and genotype-clinical phenotype associations were evaluated for the three SNPs. Our results showed that the AG genotype and the minor allele G frequency of rs1131665 and rs1061502 in AITD patients were both higher than those of the controls (rs1131665: AG genotype: P = 0.017, OR = 1.968; allele G: P = 0.018, OR = 1.946; rs1061502: AG genotype: P = 0.029, OR = 1.866; allele G: P = 0.031, OR = 1.847). Subgroup analysis also showed that the AG genotype and the minor allele G frequency of rs1131665 and rs1061502 in Graves' disease patients were both higher than those of the controls (rs1131665: AG genotype: P = 0.015, OR = 2.074; allele G: P = 0.016, OR = 2.048; rs1061502: AG genotype: P = 0.034, OR = 1.919; allele G: P = 0.035, OR = 1.898). Furthermore, the allele G frequency of rs1061501 was associated with Graves' ophthalmopathy (P = 0.035, OR = 1.396). No significant difference in IRF7 polymorphisms was found between Hashimoto's thyroiditis patients and controls. Our study has revealed for the first time that IRF7 is a susceptibility gene for AITD, especially for Graves' disease and Graves' ophthalmopathy.

Associations of melatonin receptor gene polymorphisms with Graves' disease

Background

Melatonin plays an important role in immunity and has been linked to autoimmune diseases. Possible associations of single-nucleotide polymorphisms (SNPs) of melatonin receptor type 1A (MTNR1A) and 1B (MTNR1B), with autoimmune thyroid disease in an ethnic Chinese (i.e., Taiwanese) population were examined.

Materials and methods

Totally, 83 Hashimoto’s thyroiditis patients, 319 Graves’ disease (GD), and 369 controls were recruited. Three SNPs (rs6553010, rs13140012, and rs2119882) of MTNR1A and three SNPs (rs1387153, rs10830963, and rs1562444) of MTNR1B were genotyped.

Results

There were a reduced frequency of the C allele of rs2119882 and a reduced percentage of the CC+CT genotype in the GD group compared to the control group (p = 0.039, odds ratio (OR) = 0.79, 95% confidence interval (CI) = 0.63~0.99, and p = 0.032, OR = 0.72, 95% CI = 0.53~0.97, respectively). There was a significant difference in the percentage of the AT haplotype of the combination of rs13140012 and rs2119882 between the GD and control groups (p = 0.010, OR = 1.34, 95% CI = 1.07~1.67). In addition, there were significant associations of anti-thyroid peroxidase antibody titers with rs13140012 and rs2119882, and the AATT genotype of the combination of rs13140012 and rs2119882 (p = 0.003, 0.003, and 0.004, respectively). There were no significant associations of SNPs and possible haplotypes of MTNR1B with susceptibility to GD.

Conclusions

Genetic variants of rs2119882 of MTNR1A and the AT haplotype of the combination of rs2119882 and rs13140012 were associated with GD susceptibility in an ethnic Chinese population. The results support the involvement of the melatonin pathway in the pathogenesis of GD.

Analysis of Associations of Human BAFF Gene Polymorphisms with Autoimmune Thyroid Diseases

Background

The B-lymphocyte-activating factor (BAFF) is associated with B-cell functions, and gene polymorphisms of the BAFF have been linked to autoimmune diseases (AIDs). In this study, we explored possible associations of two BAFF single-nucleotide polymorphisms (SNPs), rs1041569 and rs2893321, with autoimmune thyroid diseases (AITDs) in an ethnic Chinese population.

Material and Methods

In total, 319 Graves’ disease (GD), 83 Hashimoto’s thyroiditis (HT) patients, and 369 healthy controls were enrolled. Polymerase chain reaction-restriction fragment length polymorphism and direct sequencing were used to genotype rs2893321 and rs1041569.

Results

There was a significant difference in frequencies of the G allele and AG+GG genotype of rs2893321 between the GD and control groups (p = 0.013, odds ratio (OR) = 0.76, and p = 0.017, OR = 0.68, respectively) and between the AITD and control groups (p = 0.009, OR = 0.76, and, p = 0.014, OR = 0.69, respectively). The AA genotype of rs2893321 was associated with low titers of the thyroid-stimulating hormone receptor antibody (TSHRAb) (p = 0.015) in males but not in females. The AA genotype of rs2893321 was associated with the presence of two different types of thyroid autoantibody (TAb) (TSHRAb and Hashimoto’s autoantibody (anti-thyroglobulin or anti-microsomal antibody)) in females and with that of one type in males.

Conclusions

rs2893321 may be a susceptible genetic variant for the development of GD and AITDs. Associations of rs2893321 with susceptibility to GD and AITDs and the correlation between rs2893321 and TAb exhibit a dimorphic pattern. Additional studies with larger sample sizes are required to confirm our findings.

Fish IRF3 up-regulates the transcriptional level of IRF1, IRF2, IRF3 and IRF7 in CIK cells

Interferon Regulatory Factors (IRFs) belong to a family of transcription factor involved in transcriptional regulation of type I IFN and IFN-stimulated genes (ISG) in cells. In the present study, an IRF3 full-length cDNA (termed CiIRF3, JX999055) and its promoter sequence were cloned by homology cloning strategy and genome walking from grass carp (Ctenopharyngodon idella). The full-length cDNA sequence of CiIRF3 is comprised of a 5'UTR (195 bp), a 3'UTR (269 bp) and a largest open reading frame (ORF) of 1377 bp encoding a polypeptide of 458 amino acids. CiIRF3 has a conservative DNA-binding domain (DBD) at N-terminal and a relatively conserved interferon regulatory factors association domain (IAD). Phylogenetic tree analysis indicated that CiIRF3 gathers together with other IRF-3 from higher vertebrates in the same branch. The promoter sequence of CiIRF3 (596 bp) consists of three IRF-E, a C/EBP beta, a NF-kappa B and a TATA-BOX. CiIRF3 was constitutively expressed at low level in different grass carp tissues but was rapidly up-regulated with Poly I:C stimulation. To study the molecular mechanism of CiIRF3 regulating the transcription of IRFs, CiIRF3 was expressed in Escherichia coli BL21 and purified by affinity chromatography with the Ni-NTA His-Bind Resin. Gel mobility shift assays revealed the affinity of CiIRF3 protein with promoters of CiIRF1, CiIRF2, CiIRF3 and CiIRF7 respectively. Then, CIK cells were co-transfected with pcDNA3.1-CiIRF3, pGL3-promotor (pGL3-CiIRF1, pGL3-CiIRF2, pGL3-CiIRF3, pGL3-CiIRF7) and luciferase reporter vector respectively. The cotransfection experiment showed that CiIRF3 increased the promoter activity of CiIRF1, CiIRF2, CiIRF3 and CiIRF7. Furthermore, overexpression of CiIRF3 in CIK cells also up-regulated the expressions of CiIRF1, CiIRF2, CiIRF3 and CiIRF7. So, CiIRF3 can improve the transcriptional level of CiIRF1, CiIRF2, CiIRF3 and CiIRF7.