Yiannis Vasilopoulos

Epidermal barrier dysfunction in atopic dermatitis.

Atopic dermatitis (AD) is a multifactorial, heterogenous disease that arises as a result of the interaction between both environmental and genetic factors. Changes in at least three groups of genes encoding structural proteins, epidermal proteases, and protease inhibitors predispose to a defective epidermal barrier and increase the risk of developing AD. Loss-of-function mutations found within the FLG gene encoding the structural protein, filaggrin, represent the most significant genetic factor predisposing to AD identified to date. Enhanced protease activity and decreased synthesis of the lipid lamellae lead to exacerbated breakdown of the epidermal barrier. Environmental factors, including the use of soap and detergents, exacerbate epidermal barrier breakdown, attributed to the elevation of stratum corneum pH. A sustained increase in pH enhances the activity of degradatory proteases and decreases the activity of the lipid synthesis enzymes. The strong association between both genetic barrier defects and environmental insults to the barrier with AD suggests that epidermal barrier dysfunction is a primary event in the development of this disease. Our understanding of gene-environment interactions should lead to a better use of some topical products, avoidance of others, and the increased use and development of products that can repair the skin barrier.

Pharmacogenetic analysis of TNF, TNFRSF1A, and TNFRSF1B gene polymorphisms and prediction of response to anti-TNF therapy in psoriasis patients in the Greek population.

AbstractBackground: Although biologic therapies have revolutionized the treatment of psoriasis, patients exhibit a substantial heterogeneous response that could be due to complex genetic heterogeneity. Objective: The aim of this study was to investigate the possible influence of tumor necrosis factor-α (TNF), TNF receptor I (TNFRSF1A), and TNF receptor II (TNFRSF1B) gene polymorphisms on anti-TNF treatment responsiveness in psoriasis patients. Methods: A Greek multicenter collaboration was established to recruit a cohort of patients (n = 80) with psoriasis treated with anti-TNF drugs. Single nucleotide polymorphisms (SNPs) in TNF -238G>A, -308G>A, -857C>T), TNFRSF1A (36A>G), and TNFRSF1B (676T>G) were genotyped by PCR-restriction fragment length polymorphism assays. SNPs and haplotypes, including stratification by comorbidity status, were analyzed for association with treatment response after 6 months of therapy, defined as a reduction in the Psoriasis Area and Severity Index (PASI) score by >75% (responders) or ≤50% (nonresponders). Results: Sixty-three patients (78.8%) were defined as responders (PASI score reduction >75%) and 17 patients (21.2%) were defined as nonresponders (PASI score reduction ≤50%). Carriage of TNF -857C or TNFRSF1B 676T alleles was associated with positive response to drug treatment in patients treated with etanercept (p = 0.002 and p = 0.001, respectively). None of the genotyped SNPs were associated with responsiveness to treatment with infliximab or adalimumab. Additionally, when patients were stratified by comorbidity status, none of the genotyped SNPs were alone associated with responsiveness to drug treatment. Conclusion: This study is the first in the field of psoriasis demonstrating a strong association between genetic markers and positive response to drug treatment. Validation of this result in larger studies, as well as analysis of other drug treatments, could provide the basis for individually tailored treatment, along with increased cost effectiveness and reduced unnecessary exposure to toxicity.

A nonsynonymous substitution of cystatin A, a cysteine protease inhibitor of house dust mite protease, leads to decreased mRNA stability and shows a significant association with atopic dermatitis

Background:  Cystatin A (CSTA) is a strong candidate for atopic dermatitis (AD) because it maps to AD susceptibility locus on chromosome 3q21 and it does inhibit Der p 1 and Der f 1, major house dust mite cysteine proteases and environmental triggers for AD and asthma.

The autoimmune regulator gene (AIRE) is strongly associated with vitiligo

Background  Vitiligo is an autoimmune disorder that occurs with greatly increased frequency in the rare recessive autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy syndrome (APECED) caused by mutations of the autoimmune regulator (AIRE) gene on chromosome 21q22·3. We have previously detected an association between alopecia areata and single nucleotide polymorphisms (SNPs) in the AIRE gene.

Actin cytoskeleton dynamics linked to synovial fibroblast activation as a novel pathogenic principle in TNF‐driven arthritis

Rheumatoid arthritis is a chronic inflammatory disorder whose origin of defect has been the subject of extensive research during the past few decades. While a number of immune and non-immune cell types participate in the development of chronic destructive inflammation in the arthritic joint, synovial fibroblasts have emerged as key effector cells capable of modulating both joint destruction and propagation of inflammation. Ample evidence of aberrant changes in the morphology and biochemical behaviour of rheumatoid arthritis synovial fibroblasts have established the tissue evading and “transformed” character of this cell type. We have recently demonstrated that actin cytoskeletal rearrangements determine the pathogenic activation of synovial fibroblasts in modelled TNF-mediated arthritis, a finding correlating with similar gene expression changes which we observed in human rheumatoid arthritis synovial fibroblasts. Here, we show that pharmacological inhibition of actin cytoskeleton dynamics alters potential pathogenic properties of the arthritogenic synovial fibroblast, such as proliferation, migration and resistance to apoptosis, indicating novel opportunities for therapeutic intervention in arthritis. Recent advances in this field of research are reviewed and discussed.

Association of FCGR2A with the response to infliximab treatment of patients with rheumatoid arthritis.

Objectives We aimed to assess a functional polymorphism in FCGR2A H131R, for association with the treatment response to Fc-containing inhibitors of tumor necrosis factor (TNF). Methods A total of 429 biologic-naive patients with rheumatoid arthritis collected in two sets (299 and 130) were treated during standard care with infliximab (INX), etanercept, or adalimumab. Response to the treatment was evaluated at 3, 6, and 12 months of follow-up as the change in the Disease Activity Score (DAS) 28 from baseline and as the response by the European League Against Rheumatism (EULAR) criteria. These variables were analyzed for association with linear and logistic regression models that included sex, inhibitors of TNF, and baseline DAS28 as covariates. Results Significant association was found between the FCGR2A H131R polymorphism and the response to treatment with INX, but not with the other two TNF inhibitors. The 131R allele was associated with a lower change in DAS28 (P=0.04–0.008 at different times) in the first set of patients and confirmed in the second group of patients (P=0.026 at 3 months of follow-up). Association was also found in the comparison between nonresponders and responders to INX by the EULAR criteria. Conclusion We found an association of the FCGR2A 131R allele with poor response to INX. This finding could be of utility to understand the mechanisms behind treatment failure and contribute to biomarker panels for INX response prediction.

Genetic analysis of autoimmune regulator haplotypes in alopecia areata.

Alopecia areata is an immune-mediated disorder, occurring with the highest observed frequency in the rare recessive autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome caused by mutations of the autoimmune regulator (AIRE) gene on chromosome 21q22.3. We have previously detected association between alopecia areata and a single nucleotide polymorphism (SNP) in the AIRE gene in patients without APECED, and we now report the findings of an extended examination of the association of alopecia areata with haplotype analysis including six SNPs in the AIRE gene: C-103T, C4144G, T5238C, G6528A, T7215C and T11787C. In Caucasian groups of 295 patients and 363 controls, we found strong association between the AIRE 7215C allele and AA [P = 3.8 x 10(-8), OR (95% CI): 2.69 (1.8-4.0)]. The previously reported association between AA and the AIRE 4144G allele was no longer significant on correction for multiple testing. The AIRE haplotypes CCTGCT and CGTGCC showed a highly significant association with AA [P = 6.05 x 10(-6), 9.47 (2.91-30.8) and P = 0.001, 3.51 (1.55-7.95), respectively]. To select the haplotypes most informative for analysis, we tagged the polymorphisms using SNPTag software. Employing AIRE C-103T, G6528A, T7215C and T11787C as tag SNPs, two haplotypes were associated with AA; AIRE CGCT and AIRE CGCC [P = 3.84 x 10(-7), 11.40 (3.53-36.9) and P = 3.94 x 10(-4), 2.13 (1.39-3.24) respectively]. The AIRE risk haplotypes identified in this study potentially account for a major component of the genetic risk of developing alopecia areata.

Lack of validation of genetic variants associated with anti-tumor necrosis factor therapy response in rheumatoid arthritis: a genome-wide association study replication and meta-analysis

IntroductionIn this study, our aim was to elucidate the role of four polymorphisms identified in a prior large genome-wide association study (GWAS) in which the investigators analyzed the responses of patients with rheumatoid arthritis (RA) to treatment with tumor necrosis factor inhibitors (TNFi). The authors of that study reported that the four genetic variants were significantly associated. However, none of the associations reached GWAS significance, and two subsequent studies failed to replicate these associations.MethodsThe four polymorphisms (rs12081765, rs1532269, rs17301249 and rs7305646) were genotyped in a total of 634 TNFi-treated RA patients of Spanish Caucasian origin. Four outcomes were evaluated: changes in the Disease Activity Score in 28 joints (DAS28) after 6 and 12 months of treatment and classification according to the European League Against Rheumatism (EULAR) response criteria at the same time points. Association with DAS28 changes was assessed by linear regression using an additive genetic model. Contingency tables of genotype and allele frequencies between EULAR responder and nonresponder patients were compared. In addition, we combined our data with those of previously reported studies in a meta-analysis including 2,998 RA patients.ResultsNone of the four genetic variants showed an association with response to TNFi in any of the four outcomes analyzed in our Spanish patients. In addition, only rs1532269 yielded a suggestive association (P = 0.0033) with the response to TNFi when available data from previous studies were combined in the meta-analysis.ConclusionOur data suggest that the rs12081765, rs1532269, rs17301249 and rs7305646 genetic variants do not have a role as genetic predictors of TNFi treatment outcomes.

Association Between Polymorphisms in MTHFR and APOA5 and Metabolic Syndrome in the Greek Population

Impaired energy homeostasis and low-grade inflammation have been related to components of the metabolic syndrome (MetS) such as dyslipidemia, obesity, and insulin resistance. Single-nucleotide polymorphisms in the genes encoding for IL-6 (g.-634G>C; c.174G>C), TNFα (g.-308G>A), methylenetetrahydrofolate reductase (MTHFR) (c.677C>T), APOC3 (c.3175C>G), and APOA5 (g.-1131T>C) have been implicated in the processes of inflammation and energy intake that take place in the development of MetS manifestations. The aim of this study was to investigate the association between these polymorphisms and MetS, as defined by the National Cholesterol Education Program-Adult treatment Panel III criteria, in the Greek population. Overall, 30 unrelated subjects who met the criteria of MetS and 60 matched control subjects from central Greece were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis. There was a significant association between both MTHFR c.677C>T (odds ratio: 4.02; confidence interval: 1.496-10.777; p=0.003) and APOA5 g.-1131T>C (odds ratio: 3.514; confidence interval: 1.065-11.585; p=0.035) and MetS. Analysis of constructed haplotypes showed a highly significant association between 677C-1131T-3175C haplotype and MetS (p<0.0001). Carriers of both MTHFR c.677T and APOA5 g.-1131C were associated with increased triglyceride levels (p=0.001 and p=0.003, respectively), compared with noncarriers. These results support a role for MTHFR and APOA5 as risk factors for MetS and suggest their further validation in larger independent populations.

Association analysis of the skin barrier gene cystatin A at the PSORS5 locus in psoriatic patients: evidence for interaction between PSORS1 and PSORS5

Family-based analysis has revealed several loci for psoriasis and the locus, PSORS5, on chromosome 3q21 has been found in two independent studies. In this region, cystatin A (CSTA) encodes a skin barrier cystein protease inhibitor found in human sweat and it is over-expressed in psoriatic skin. Three CSTA markers at positions –190 (g.−190T>C), +162 (c.162T>C) and +344 (c.344C>T) were analysed in 107 unrelated patients and 216 matched controls. There was a significant trend for association with CSTA c.162T>C and psoriasis (odds ratio (OR)=3.45, P<0.001). Analysis of constructed haplotypes showed a highly significant association between disease and CSTA –190T/+162C/+344C (CSTA TCC) (P=10−6). In independent study, a TDT analysis in 126 nuclear families confirmed the over-transmission of CSTA TCC (P=0.0001). The presence of statistical interaction between CSTA TCC haplotype and HLA-Cw6 at PSORS1 locus was detected by performing TDT analysis on CSTA haplotypes stratified by the presence or absence of the risk allele at HLA-Cw6 locus. To estimate the disease risk we employed conditional logistic regression on the family data. The CSTA TCC haplotype is only associated with psoriasis in those individuals carrying the risk allele at the HLA-Cw6 locus (OR=2.22, P=0.0004, 95% CI= 1.42, 3.49). These results represent a major step towards the dissection of genetic factors involved in the pathogenesis of psoriasis.