Stana Tokić

Lack of association of vitamin D receptor gene 3′‐haplotypes with psoriasis in Croatian patients

Cis‐acting regulatory variants in biologically relevant pathways and target tissues are a common source of phenotypic variations and individual disease susceptibility. In the skin, vitamin D receptor (VDR) is a master regulator of epidermal barrier function, inflammation, stem cell proliferation and microbial defense; therefore, we tested whether VDR 3′‐regulatory haplotypes, a portion of which affect VDR transcriptional efficiency, allelic symmetry and mRNA turnover, were associated with psoriasis vulgaris. For this purpose, three VDR tag polymorphisms that capture most of the variability of the VDR 3′‐regulatory element (rs1544410, rs7975232 and rs731236) were genotyped by the polymerase chain reaction restriction fragment length polymorphism method in 180 Caucasian patients with chronic plaque psoriasis and 366 ethnically matched, healthy controls of the Croatian origin. We found no evidence of association for any of the selected polymorphisms. Similarly, none of the 3′‐VDR restriction haplotypes were associated with the risk for development of psoriasis in Croatian patients. These results show that neither VDR 3′‐restriction polymorphisms nor common 3′‐regulatory haplotypes contribute to psoriasis risk in the Croatian population.

The Expression of T Cell FOXP3 and T-Bet Is Upregulated in Severe but Not Euthyroid Hashimoto's Thyroiditis

Hashimotos thyroiditis (HT) is an organ-specific autoimmune disorder characterized by progressive thyroid failure. Th1 and Treg subset of CD4+ cells have been implicated in the pathogenesis; however, less is known about their respective roles across the spectrum of HT clinical presentations. To shed more light on CD4+ subsets role in HT, we investigated the mRNA expression levels of several Th1/Treg-associated transcription factors (T-bet/ETS1, HIF1α/BLIMP1/FOXP3) in peripheral blood T cells of 10 hypothyroid, untreated HT patients, 10 hypothyroid patients undergoing hormone replacement therapy, 12 euthyroid HT subjects, and 11 healthy controls by the qRT-PCR. Compared to euthyroid HT patients and controls, both hypothyroid (2.34-fold difference versus controls, P < 0.01) and thyroxine-supplemented patients (2.5-fold, P < 0.001) showed an increased FOXP3 mRNA expression in T cells. Similarly, mRNA expression levels of T-bet were upregulated in severely affected but not in euthyroid HT subjects (2.37-fold and 3.2-fold, hypothyroid and thyroxine-supplemented HT patients versus controls, resp., P < 0.01). By contrast, no differences in mRNA expression levels of ETS1, BLIMP1, and HIF1α were observed across the study groups. In summary, severe but not euthyroid HT was associated with robust upregulation of T-bet and FOXP3 mRNA in peripheral T cells, independent of the thyroid hormone status but proportional to disease activity.

Pilot study of variants of the IL-23R and STAT3 genes reveals no association with Hashimoto’s thyroiditis in the Croatian population

Abstract Interleukin-23 receptor (IL-23R) and signal transducer and activator of transcription 3 (STAT3) polymorphisms are common risk factors for a number of T helper (Th) 17-mediated autoimmune diseases. However, the importance of genetic variations in Th17 pathways to thyroid autoimmunity, and particularly Hashimoto’s thyroiditis (HT), is not fully understood. In this study, we genotyped three single nucleotide polymorphisms (SNPs) within the IL-23R (rs11209026/p.Arg381Gln, rs7530511) and STAT3 (rs744166) genes in 217 Croatian patients with HT and 161 healthy controls using fluorescence resonance energy transfer technology and melting curve analysis of polymerase chain reaction products. None of the tested SNPs or IL-23R haplotypes was associated with HT susceptibility or disease severity. These results suggest that the studied IL-23R/STAT3 polymorphisms affecting Th17 signaling efficiency are not major determinants of HT risk in the Croatian population. Further work is necessary to determine if these loci contribute modestly or conditionally to the risk of HT.

Expression of TIGIT and FCRL3 is Altered in T Cells from Patients with Distinct Patterns of Chronic Autoimmune Thyroiditis

BACKGROUND Co-inhibitory receptors (IR), such as TIGIT and FCRL3, provide a checkpoint against highly destructive immune responses. Co-expression of TIGIT and FCRL3, in particular, has been linked to the HELIOS+ subset of regulatory CD4+FOXP3+T-cells. Of these, CD4+FOXP3-exon(E)2+ cells have higher expression of IR and exhibit strongest suppressive properties. Nevertheless, how the expression of TIGIT, FCRL3, HELIOS, and FOXP3E2 is regulated in chronic autoimmune thyroiditis (AT), is not known. METHODS Thirty patients with AT [encompassing spontaneously euthyroid (euAT), hypothyroid-untreated and L-thyroxine-treated cases)] and 10 healthy controls (HC) were recruited. FCRL3, TIGIT, HELIOS and FOXP3E2 mRNA expression levels in peripheral blood (PB) T cells were measured via quantitative real-time PCR and compared to clinicopathological factors. RESULTS The TIGIT and FCRL3 expression levels from T cells of AT cases were inversely related to the thyroid volume, and were significantly increased in hypothyroid patients (on+off L-thyroxine), but not euAT cases. The FCRL3 expression in PB T cells positively correlated with thyroid-peroxidase autoantibody levels; by contrast, T cells from aged AT patients and combined samples (AT+HC) accumulated more TIGIT mRNA. The patients with higher TIGIT mRNA levels had a greater prevalence of hypothyroidism, showing higher peak thyrotropin levels at diagnosis or at follow-up. CONCLUSIONS Multiple IR, namely FCRL3 and TIGIT, but not the transcription factors HELIOS and FOXP3E2, showed increased mRNA levels in PB T cells from end-stage, long-standing and/or more aggressive AT, in proportion to disease severity. A relation with major clinical subphenotypes was observed, thereby identifying IR as potentially important players in AT.

Zmiana ekspresji mRNA dla CTLA-4, CD28, VDR i CD45 w limfocytach T u osób z chorobą Hashimoto — badanie pilotowe

INTRODUCTION CD28/T-cell receptor (TCR)/cytotoxic T-lymphocyte antigen 4 (CTLA4) complex controls T-cell tolerance and autoimmunity in Hashimotos thyroiditis (HT). In addition, CD45 protein tyrosine phosphatase (PTPase) and vitamin D receptor (VDR) cooperatively interact with the TCR complex to affect autoimmune processes central to the pathogenesis of HT. Nevertheless, their role in HT aetiology has been less well established. In this study, we aimed to explore mRNA expression levels of CTLA4, CD28, CD45, and VDR in T-cells, across different outcomes of HT. MATERIAL AND METHODS The study included 45 HT patients and 13 euthyroid, healthy controls. T-lymphocytes were isolated from peripheral blood mononuclear cells, total mRNA was extracted from T-cells, and gene expression was studied by reverse transcription-polymerase chain reaction (RT-PCR) and ImageQuant method relative to glyceraldehyde-3-phosphate dehydrogenase RT-PCR products. RESULTS Nominally higher expression levels of VDR, CTLA4, CD28, and CD45RAB mRNA were found in unsorted T-lymphocytes of healthy controls when compared to the HT patients. No difference was observed between hypothyroid/untreated, spontaneously euthyroid and LT4-treated HT patients. VDR mRNA expression was linked to both T3 levels and CTLA4 gene expression, whilst CD45RB mRNA expression coincided with CTLA4 and CD28 transcript levels. Conversely, older age and lower T3 levels were associated with increased abundance of CD45R0 isoform in HT patients. CONCLUSIONS The results suggest a cross talk between endocrine and immune functions in HT pathology: an altered peripheral T cell mRNA profile with reduced VDR, CTLA4, CD28, and CD45RAB transcript levels is accompanied by age-related shift from naive to memory/late-differentiated T cell CD45R mRNA signature and associated with thyroid hormone status in the HT patients.