Microsomal PGE synthase 1 (mPGES-1) is the terminal enzyme in the induced state of prostaglandin E-2 (PGE(2)) synthesis and constitutes a therapeutic target for rheumatoid arthritis (RA) treatment.... Show moreMicrosomal PGE synthase 1 (mPGES-1) is the terminal enzyme in the induced state of prostaglandin E-2 (PGE(2)) synthesis and constitutes a therapeutic target for rheumatoid arthritis (RA) treatment. We examined the role of the prostaglandin E synthase (PTGES) gene polymorphism in susceptibility to and severity of RA and related variations in the gene to its function. The PTGES gene polymorphism was analyzed in 3081 RA patients and 1900 controls from two study populations: Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) and the Leiden Early Arthritis Clinic (Leiden EAC). Baseline disease activity score (DAS28) was employed as a disease severity measure. mPGES-1 expression was analyzed in synovial tissue from RA patients with known genotypes using immunohistochemistry. In the Swedish study population, among women a significant association with risk for RA was observed for PTGES single-nucleotide polymorphisms (SNPs) in univariate analysis and for the distinct haplotype. These results were substantiated by meta-analysis of data from EIRA and Leiden EAC studies with overall OR 1.31 (95% confidence interval 1.11-1.56). Several PTGES SNPs were associated with earlier onset of disease or with higher DAS28 in women with RA. Patients with the genotype associated with higher DAS28 exhibited significantly higher mPGES-1 expression in synovial tissue. Our data reveal a possible influence of PTGES polymorphism on the pathogenesis of RA and on disease severity through upregulation of mPGES-1 at the sites of inflammation. Genetically predisposed individuals may develop earlier and more active disease owing to this mechanism. European Journal of Human Genetics (2011) 19, 908-914; doi:10.1038/ejhg.2011.50; published online 30 March 2011 Show less
Cui, J.; Saevarsdottir, S.; Thomson, B.; Padyukov, L.; Helm-van Mil, A.H.M. van der; Nititham, J.; ... ; Ge 2010
Objective. Anti-tumor necrosis factor alpha (anti-TNF) therapy is a mainstay of treatment in rheumatoid arthritis (RA). The aim of the present study was to test established RA genetic risk factors... Show moreObjective. Anti-tumor necrosis factor alpha (anti-TNF) therapy is a mainstay of treatment in rheumatoid arthritis (RA). The aim of the present study was to test established RA genetic risk factors to determine whether the same alleles also influence the response to anti-TNF therapy. Methods. A total of 1,283 RA patients receiving etanercept, infliximab, or adalimumab therapy were studied from among an international collaborative consortium of 9 different RA cohorts. The primary end point compared RA patients with a good treatment response according to the European League Against Rheumatism (EULAR) response criteria (n = 505) with RA patients considered to be nonresponders (n = 316). The secondary end point was the change from baseline in the level of disease activity according to the Disease Activity Score in 28 joints (Delta DAS28). Clinical factors such as age, sex, and concomitant medications were tested as possible correlates of treatment response. Thirty-one single-nucleotide polymorphisms (SNPs) associated with the risk of RA were genotyped and tested for any association with treatment response, using univariate and multivariate logistic regression models. Results. Of the 31 RA-associated risk alleles, a SNP at the PTPRC (also known as CD45) gene locus (rs10919563) was associated with the primary end point, a EULAR good response versus no response (odds ratio [OR] 0.55, P = 0.0001 in the multivariate model). Similar results were obtained using the secondary end point, the Delta DAS28 (P = 0.0002). There was suggestive evidence of a stronger association in autoantibody-positive patients with RA (OR 0.55, 95% confidence interval [95% CI] 0.39-0.76) as compared with autoantibody-negative patients (OR 0.90, 95% CI 0.41-1.99). Conclusion. Statistically significant associations were observed between the response to anti-TNF therapy and an RA risk allele at the PTPRC gene locus. Additional studies will be required to replicate this finding in additional patient collections. Show less
Seddighzadeh, M.; Korotkova, M.; Kallberg, H.; Ding, B.; Daha, N.; Kurreeman, F.A.S.; ... ; Padyukov, L. 2010
It has repeatedly been suggested that the development of complex diseases can be elucidated by gene-gene interactions. Recently, we found that HTR2A, a member of the serotonin receptor family, is... Show moreIt has repeatedly been suggested that the development of complex diseases can be elucidated by gene-gene interactions. Recently, we found that HTR2A, a member of the serotonin receptor family, is associated with rheumatoid arthritis (RA). This study was aimed to investigate the possibility of a gene-gene interaction between HTR2A and the major genetic risk factor for RA, HLA-DRB1 shared epitope (SE) alleles. We studied 4095 RA cases and 3223 controls from three different populations from Sweden, the United States and the Netherlands - to test for interaction between the protective HTR2A haplotype and HLA-DRB1 SE alleles. Further, we analyzed mRNA and/or protein expression of HTR2A and HLA-DR in biopsy samples and in synovial fibroblasts from RA patients. The interaction was defined as departure from additivity of effects using attributable proportion due to interaction. First, we could demonstrate and further replicate an interaction between a protective haplotype in HTR2A and HLA-DRB1 SE alleles regarding risk of developing autoantibody-positive RA. Second, we could show that both genes are constitutively expressed in fibroblasts from synovial tissue of RA patients, and, by double immunofluorescence staining, we demonstrated that these two proteins are colocalized in these cells. In conclusion, our data demonstrate a statistical interaction between HTR2A and HLA-DRB1 SE alleles and colocalization of the product of these two genes in inflamed synovial tissue, which suggest a possible biological relationship between these two proteins. This finding may lead to the development of treatment based on enhancing the protective features of 5-HT2A in individuals with a certain HLA genotype. European Journal of Human Genetics (2010) 18, 821-826; doi: 10.1038/ejhg.2010.12; published online 24 February 2010 Show less
To identify new genetic risk factors for rheumatoid arthritis, we conducted a genome-wide association study meta-analysis of 5,539 autoantibody-positive individuals with rheumatoid arthritis (cases... Show moreTo identify new genetic risk factors for rheumatoid arthritis, we conducted a genome-wide association study meta-analysis of 5,539 autoantibody-positive individuals with rheumatoid arthritis (cases) and 20,169 controls of European descent, followed by replication in an independent set of 6,768 rheumatoid arthritis cases and 8,806 controls. Of 34 SNPs selected for replication, 7 new rheumatoid arthritis risk alleles were identified at genome-wide significance (P < 5 x 10(-8)) in an analysis of all 41,282 samples. The associated SNPs are near genes of known immune function, including IL6ST, SPRED2, RBPJ, CCR6, IRF5 and PXK. We also refined associations at two established rheumatoid arthritis risk loci (IL2RA and CCL21) and confirmed the association at AFF3. These new associations bring the total number of confirmed rheumatoid arthritis risk loci to 31 among individuals of European ancestry. An additional 11 SNPs replicated at P < 0.05, many of which are validated autoimmune risk alleles, suggesting that most represent genuine rheumatoid arthritis risk alleles. Show less
