RESUMO
Objectives: The arachidonate 5-lipoxygenase activating protein (ALOX5AP) regulates synthesis of leukotrienes (LTs), which are important mediators of inflammation and connective tissue remodelling. The aim of this study was to evaluate if single nucleotide polymorphisms (SNPs) of ALOX5AP confer risk of SSc and/or SSc-related organ involvement. Methods: Seven SNPs of ALOX5AP (rs17222814, rs17216473, rs10507391, rs4769874, rs9551963, rs9315050 and rs7222842) were genotyped in a cohort of 977 patients with SSc and 558 healthy controls from centres collaborating within the European Scleroderma Trials and Research group. In 22 SSc patients, concentrations of cysteinyl LTs and LT B4 (LTB4) were measured in the supernatants of ionophore-stimulated peripheral blood mononuclear cells (PBMCs) by means of commercially available enzyme immunoassay kits. Results: Significant association was found between rs10507391 polymorphism (T/A) of ALOX5AP and the risk of SSc [odds ratio (OR) 1.27 (95% CI 1.07, 1.50), P < 0.05 vs controls], the presence of SSc-related interstitial lung disease on high-resolution CT of the lungs [OR 1.45 (95% CI 1.17, 1.79), P < 0.05 vs patients without SSc-related interstitial lung disease] as well as with restrictive ventilatory defect [forced vital capacity <70% of predicted; OR 1.51 (95% CI 1.16, 1.97), P < 0.05 vs SSc patients without pulmonary restriction]. PBMCs from SSc carriers of rs10507391 allele A synthesized greater amounts of cysteinyl LTs as compared with SSc patients with rs10507391 TT genotype ( P < 0.05). Synthesis of LTB4 did not differ significantly between the two groups. Conclusion: The results of our study indicate that the genetic variants of ALOX5AP might play a role in the development of SSc-related pulmonary fibrosis.
Assuntos
Proteínas Ativadoras de 5-Lipoxigenase/genética , Polimorfismo de Nucleotídeo Único/genética , Fibrose Pulmonar/genética , Escleroderma Sistêmico/genética , Estudos de Casos e Controles , Células Cultivadas , Feminino , Frequência do Gene , Heterozigoto , Homozigoto , Humanos , Leucócitos Mononucleares/fisiologia , Masculino , Transtornos Respiratórios/genéticaAssuntos
Adenosina Trifosfatases/genética , Escleroderma Sistêmico/genética , Anticorpos Antinucleares/imunologia , Autoanticorpos/imunologia , Estudos de Casos e Controles , Estudos de Coortes , DNA Topoisomerases Tipo I/imunologia , Humanos , Mutação de Sentido Incorreto , Escleroderma Sistêmico/imunologia , População Branca/genéticaRESUMO
Systemic sclerosis (SSc) and systemic lupus erythematosus (SLE) are two archetypal systemic autoimmune diseases which have been shown to share multiple genetic susceptibility loci. In order to gain insight into the genetic basis of these diseases, we performed a pan-meta-analysis of two genome-wide association studies (GWASs) together with a replication stage including additional SSc and SLE cohorts. This increased the sample size to a total of 21,109 (6835 cases and 14,274 controls). We selected for replication 19 SNPs from the GWAS data. We were able to validate KIAA0319L (P = 3.31 × 10(-11), OR = 1.49) as novel susceptibility loci for SSc and SLE. Furthermore, we also determined that the previously described SLE susceptibility loci PXK (P = 3.27 × 10(-11), OR = 1.20) and JAZF1 (P = 1.11 × 10(-8), OR = 1.13) are shared with SSc. Supporting these new discoveries, we observed that KIAA0319L was overexpressed in peripheral blood cells of SSc and SLE patients compared with healthy controls. With these, we add three (KIAA0319L, PXK and JAZF1) and one (KIAA0319L) new susceptibility loci for SSc and SLE, respectively, increasing significantly the knowledge of the genetic basis of autoimmunity.