Fas/FasL gene polymorphism in patients with Hashimoto's thyroiditis in Turkish population

A rare co-existence of histiocytic necrotizing lymphadenitis with metastatic papillary thyroid carcinoma and review of the literature

Histiocytic necrotizing lymphadenitis (HNL) is a benign, self-limiting disease that is rare clinically. The coexistence of HNL and tumor is rarer. We report a male patient who was preoperatively diagnosed with papillary thyroid carcinoma with cervical lymph nodes metastasis, and the postoperative pathological examination showed histiocytic necrotizing lymphadenitis combined with metastatic papillary thyroid carcinoma in the same single lymph node. More interestingly, Epstein‒Barr virus was positive in these lymph nodes by in situ hybridization. This may suggest a trigger for the coexistence of the two diseases.

Excessive iodine induces thyroid follicular epithelial cells apoptosis by activating HIF-1α-mediated hypoxia pathway in Hashimoto thyroiditis

BACKGROUND

Hashimoto thyroiditis (HT) is considered the most common autoimmune thyroid disease. A growing body of evidence suggests that HT incidence correlates with excessive iodine intake. We should probe the effects of excessive iodine intake in HT development and its possible mechanism.

METHODS AND RESULTS

The study recruited 20 patients: 10 with HT and 10 with nodular goiter. We detected the expression of an apoptosis-related protein caspase-3 by immunohistochemistry. In vitro study, we explored the proliferation and apoptosis status in thyroid follicular cells (TFCs) stimulated with different iodine concentrations by MTT and flow cytometry. Then we performed RNA sequence analysis of Nthy-ori3-1 cells treated for 48 h with KI to probe the underlying mechanism. Finally, we used RT-PCR and siRNA interference to verify the results. We identified apoptosis in thyroid tissue obtained from HT patients coincides with the increase of caspase-3 levels. In vitro study, iodine suppressed proliferation of TFCs and promoted TFCs apoptosis in a dose-dependent manner with regulating caspase-3 activation. HIF-1α-NDRG1 mediated hypoxia pathway activation promoted the transmission of essential apoptosis signals in TFCs.

CONCLUSION

Our study confirmed that excessive iodine adsorption activates the HIF-1α-mediated hypoxia pathway to promote apoptosis of TFCs, which may be an important risk factor contributing to HT development.

ALPS, FAS, and beyond: from inborn errors of immunity to acquired immunodeficiencies

Autoimmune lymphoproliferative syndrome (ALPS) is a primary immune regulatory disorder characterized by benign or malignant lymphoproliferation and autoimmunity. Classically, ALPS is due to mutations in FAS and other related genes; however, recent research revealed that other genes could be responsible for similar clinical features. Therefore, ALPS classification and diagnostic criteria have changed over time, and several ALPS-like disorders have been recently identified. Moreover, mutations in FAS often show an incomplete penetrance, and certain genotypes have been associated to a dominant or recessive inheritance pattern. FAS mutations may also be acquired or could become pathogenic when associated to variants in other genes, delineating a possible digenic type of inheritance. Intriguingly, variants in FAS and increased TCR αβ double-negative T cells (DNTs, a hallmark of ALPS) have been identified in multifactorial autoimmune diseases, while FAS itself could play a potential role in carcinogenesis. These findings suggest that alterations of FAS-mediated apoptosis could trespass the universe of inborn errors of immunity and that somatic mutations leading to ALPS could only be the tip of the iceberg of acquired immunodeficiencies.

Association between FAS gene -670 A/G and -1377 G/A polymorphisms and the risk of autoimmune diseases: a meta-analysis

Objectives: FAS plays a critical role in the extrinsic apoptosis pathway in autoimmune diseases. Previous studies investigating the association between FAS gene −670 A/G and −1377 G/A polymorphisms and the risk of autoimmune diseases reported controversial results. We performed the meta-analysis to evaluate the possible association. Methods: Relevant studies were identified by searching the PubMed, Embase, CNKI, and Wanfang databases up to December 2018. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to determine the association. Results: A total of 43 articles including 67 studies (52 studies for FAS −670 A/G and 15 studies for −1377 G/A) were included in the meta-analysis. Our meta-analysis showed that the FAS −670 A/G polymorphism was associated with the risk of autoimmune diseases (GG vs. GA: OR = 1.079, 95% CI = 1.004–1.160, P=0.038), especially in Caucasians (GG vs. GA: OR = 1.12, 95% CI = 1.03–1.23, P=0.012), Asians (G vs. A: OR = 0.89, 95% CI = 0.83–0.96, P=0.002), systemic lupus erythematosus (SLE) (G vs. A: OR = 0.85, 95% CI = 0.77–0.94, P=0.001), multiple sclerosis (MS) (GG+GA vs. AA: OR = 0.83, 95% CI = 0.70–0.99, P=0.043), systemic sclerosis (SSc) (GG vs. GA: OR = 1.20, 95% CI = 1.07–1.36, P=0.003) and Hashimoto’s thyroiditis (HT) (G vs. A: OR = 1.45, 95% CI = 1.10–1.90, P=0.008); the FAS −1377 G/A polymorphism was associated with the risk of autoimmune diseases (A vs. G: OR = 1.11, 95% CI = 1.03–1.20, P=0.008), especially in Asians (A vs. G: OR = 1.15, 95% CI = 1.05–1.25, P=0.002) and high quality studies (A vs. G: OR = 1.14, 95% CI = 1.05–1.24, P=0.002). Conclusion: This meta-analysis demonstrated that the FAS –670A/G and –1377 G/A polymorphisms were associated with the risk of autoimmune diseases.

Genetic Susceptibility to Joint Occurrence of Polycystic Ovary Syndrome and Hashimoto's Thyroiditis: How Far Is Our Understanding?

Polycystic ovary syndrome (PCOS) and Hashimoto’s thyroiditis (HT) are endocrine disorders that commonly occur among young women. A higher prevalence of HT in women with PCOS, relative to healthy individuals, is observed consistently. Combined occurrence of both diseases is associated with a higher risk of severe metabolic and reproductive complications. Genetic factors strongly impact the pathogenesis of both PCOS and HT and several susceptibility loci associated with a higher risk of both disorders have been identified. Furthermore, some candidate gene polymorphisms are thought to be functionally relevant; however, few genetic variants are proposed to be causally associated with the incidence of both disorders together.

Microorganisms associated to thyroid autoimmunity

Autoimmune thyroid diseases are a group of diseases characterized by a dysfunction of the immune system concerning the thyroid gland, associated with hypothyroidism or hyperthyroidism. The thyroid gland autoimmunity has been recognized as multifactorial. It has been reported that microorganisms may play a role on the pathogenesis of Hashimoto's thyroiditis and Graves´ disease. These could explain the high incidence of the autoimmune thyroid diseases. Helicobacter Pylori (H. pylori) and Hepatitis C virus (HCV) are the microorganisms in which the association with autoimmune thyroid diseases is clearer. The pathophysiologic mechanisms are still not well defined. For H. pylori, molecular mimicry has been the most accepted mechanism. It has been proposed Hepatitis C virus as the trigger of the thyroid autoimmunity by exacerbating the production of thyroid auto-antibodies, while some mention that the real factor that triggers the thyroid autoimmunity is the treatment with Interferon alpha (IFN-alpha) by upregulating MHC class I and inducing ligation of CD40+ cells to thyrocytes. Other microorganisms such as Toxoplasma gondii, Human Immunodeficiency virus, Herpes virus and others have reported information about their association with thyroid autoimmune diseases There are no proposals on how these last microorganisms induce thyroid autoimmunity. There is still a lack of evidence on this topic. Further research must be done to determine the interaction of these microorganisms and the best way to manage these patients.

CEP128 is a crucial risk locus for autoimmune thyroid diseases

Autoimmune thyroid disease (AITD) mainly includes Graves' disease (GD) and Hashimoto's thyroiditis (HT), and its pathogenesis is not clearly defined. This study was designed to explore risk loci for AITD. Genome-wide genetic data were analyzed to identify important risk loci for GD, and a case-control study with 845 AITD patients and 694 healthy controls was also conducted. The functional role of possible risk loci for GD was explored by analyzing the correlations of Centrosomal protein 128 (CEP128) expression level with intrathyroidal immune cells and key genes for candidate immune cells in GD thyroid tissues. CEP128 was identified as an important risk locus for GD in the genome-wide genetic analysis, and it was located near TSHR without obvious linkage disequilibrium with TSHR. Two tag single-nucleotide variants in CEP128 including a missense variant rs327463 were substantially related to genetic predisposition to GD and HT in the case-control study. CEP128 rs327463 was substantially related to GD under the allele model (OR = 1.31, 95%CI 1.08-1.59, P = 0.006) and the dominant model (OR = 1.37, 95%CI 1.09-1.72, P = 0.008), and it was related to HT under the recessive model (OR = 1.85, P = 0.031) and the homozygous model (OR = 1.91, P = 0.025). Moreover, CEP128 was substantially correlated with the frequencies of T-follicular helper (Tfh) cell and M1 macrophages in GD tissues. Gene set enrichment analysis suggested that CEP128 was related to several common immune pathways involved in GD pathogenesis, such as interferon-γ mediated signaling pathway and toll-like receptor signaling pathway. This study highlight the crucial role of CEP128 in the pathogenesis of GD, and polymorphisms in CEP128 contribute to genetic predisposition to both GD and HT.

How much of the predisposition to Hashimoto's thyroiditis can be explained based on previously reported associations?

PURPOSE

Our insight in the genetics of Hashimoto's thyroiditis (HT) has become clearer through information provided by genome-wide association studies and candidate gene studies, but remains still not fully understood. Our aim was to assess how many different genetic risk variants contribute to the development of HT.

METHODS

147 HT cases (10.2% men) and 147 controls (13.6% men) were qualified for the analysis. Intrinsic and environmental factors were controlled for. Polymorphisms (SNP) were chosen based on the literature and included markers of the genes PTPN22, CTLA4, TG, TPO among others, and of genomic regions pointed by GWAS studies. SNP were typed on a microarray. Variants in the HLA-DRB1 gene were identified by Sanger sequencing.

RESULTS

Multivariate predisposition to HT was modeled. Based on the investigated group, a model of seven variables was obtained. The variability explained by this model was assessed at only 5.4821% (p = 2 × 10^-6), which indicates that many dozens of factors are required simultaneously to explain HT predisposition.

CONCLUSIONS

We analyzed genetic regions commonly and most significantly associated with autoimmune thyroid disorders in the literature, on a carefully selected cohort. Our results indicated a lack of possibility to predict the risk of HT development, even with a multivariate model. We therefore conclude that strong associations of single genetic regions with HT should be interpreted with great caution. We believe that a change in the attitude towards genetic association analyses of HT predisposition is necessary. Studies including multiple factors simultaneously are needed to unravel the intricacies of genetic associations with HT.

Nuclear factor-kappa B activation inhibits proliferation and promotes apoptosis of vascular smooth muscle cells

Objectives

To investigate the role of nuclear factor-kappa B (NF-κB) performed in cell proliferation and apoptosis of vascular smooth muscle cells (VSMCs), and to assess the mechanisms.

Methods

Human aorta VSMCs were divided into control, NF-κB inhibitor, NF-κB overexpression + NF-κB inhibitor, control vector + NF-κB inhibitor, NF-κB overexpression, and control vector groups. NF-κB overexpression vector was constructed and transfected into VSMCs. Proliferation of VSMCs in each group was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide. Apoptosis of VSMCs was detected by flow cytometry. The expression of NF-κB, FasL, and hypertension-related gene (HRG-1) was measured by Western blotting.

Results

NF-κB overexpression vector was constructed correctly by restriction endonuclease, and the results showed that the activation of NF-κB could inhibit the proliferation of VSMCs. The results of flow cytometry also confirmed that NF-κB overexpression promoted apoptosis of VSMCs. Mechanically, NF-κB overexpression could up-regulate the expression of FasL and HRG-1.

Conclusions

NF-κB overexpression promotes apoptosis and inhibits cell proliferation of VSMCs. The mechanisms might be regulated by promoting FasL and HRG-1 expression.