Anti-M3 muscarinic acetylcholine receptor antibodies in systemic lupus erythematosus

Background: Evidences have shown that anti-M3 muscarinic acetylcholine receptor IgG (anti-M3 mAChR IgG) are clinically useful autoantibody that exert a cholinergic pharmacologic effect binding and interacting with M3 mAChR at the level of exocrine gland (salivary and ocular). Aims: The aim of this study was to determine the associations between serum level of anti-M3 mAChR IgG in patients with systemic lupus erythematosus (SLE) and other autoantibodies, serum prostaglandin E2 (PGE2), and clinical manifestations. Methods: Serum autoantibodies against M3 mAChR synthetic peptide were measured by enzyme-linked immuno absorbent assay (ELISA) using, as an antigen, a 25-mer peptide K-R-T-V-P-D-N-Q-C-F-I-Q-F-L-S-N-P-A-V-T-F-G-T-A-I corresponding to the amino acid sequence of the second extracellular loop of the human M3 mAChR. Serum levels of antinuclear antibodies (ANA), anti-Smith (Sm) antibodies, anti-phospholipid (APL) antibodies, and PGE2 were determined by ELISA in patients with SLE. Results: We found significantly enhanced titers of anti-M3 mAChR IgG in sera from SLE patients compared with healthy individuals (control). In addition, serum levels of PGE2 were significantly higher in SLE patients than in control patients and were significantly higher in active than in non-active SLE. No correlation was found with other autoantibodies present in SLE. By contrast, a positive correlation was found between anti-M3 mAChR IgG and PGE2 serum levels in SLE. Conclusions: As anti-M3 mAChR antibodies present in the sera of SLE patients may be another factor in the pathogenesis of this disease, and the increment of PGE2 in the sera of SLE has a modulatory action on the inflammatory process, suggesting that the presence of these autoantibodies against M3 mAChR may contribute to sustained immune deregulation and the strong inflammatory component observed in SLE.Fil: Reina, Silvia Lorena. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pisoni, Cecilia. Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”; ArgentinaFil: Eimon, Alicia. Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”; ArgentinaFil: Carrizo, Carolina. Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”; ArgentinaFil: Arana, Roberto. Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”; ArgentinaFil: Borda, Enri Santiago. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Changes in Cyclooxygenase-2’s Expression, and PGE2 ’s and 6-keto-PGF1α’s Levels in the Presence of the Muscarinic Acethylcholine Receptor Antibody in Primary Sjögren Syndrome

AbstractAims: This paper investigates the action of M3 muscarinic acetylcholine receptor antibody present in serum from patients with Sjögren syndrome (SS). Methods: Enzyme-linked immunoabsorbent assay (ELISA) was performed in the presence or absence of different enzymatic and specific receptors?antagonist drugs. The levels and the generation of PGE2, 6-keto-PGF1α and cyclic AMP (cAMP) in rat submandibular gland acini?s preparations and in serum from pSS patients were measured in the presence of pSS IgG anti M3 peptide. COX-2 mRNA gene?s expression at Real Time PCR was done in acini?s preparations from rat submandibular gland in the presence of the autoantibodies alone or once previously incubated with different inhibitors.Results: In this study, we show that the activation of M3 mAChR of rat submandibular gland acini?s preparation triggers an increment both in the production of COX-2 mRNA gene?s expression and in the production of PGE2 and 6-keto-PGF1α. These phenomena are accompanied by an increment in the production of cAMP in the acini?s preparation and do not affect COX-1 mRNA?s levels. Both prostanoids are augmented in the sera of pSS patients as compared with healthy individuals.Conclusions: The present study suggests a complex interplay between different factors involved in adaptativa autoimmunity in pSS patients at the level of exocrine glands. The presence of pSS IgG anti M3 peptide, the enhancement of COX-2 mRNA gene?s expression and the increment in the generation of PGE2 and 6-keto-PGF1α abolished by M3 specific cholinergic antagonist, could provide evidence of a link between autoimmunity and the submandibular gland parasympathetic system in the course of Sjögren?s syndrome. This evidence is further supported by an increment in the production of AMP cyclic nucleotide (cAMP), and the subsequent induction of desensitization, internalization and/or intracellular degradation of the glandular M3 mAChR displayed by the cholinergic autoantibody. All of these statements cited above, are responsible for xerostomy, xerophthalmia and other parasympathetic symptoms observed in SS patients.Fil: Reina, Silvia Lorena. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pisoni, Cecilia. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Eimon, Alicia. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Carrizo, Carolina. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Ganzinelli, Sabrina Belen. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arana, Roberto. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; ArgentinaFil: Borda, Enri Santiago. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Monocytes from Sjögren's syndrome patients display increased vasoactive intestinal peptide receptor 2 expression and impaired apoptotic cell phagocytosis

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by salivary and lacrimal gland dysfunction. Clinical observations and results from animal models of SS support the role of aberrant epithelial cell apoptosis and immune homeostasis loss in the glands as triggering factors for the autoimmune response. Vasoactive intestinal peptide (VIP) promotes potent anti-inflammatory effects in several inflammatory and autoimmune disease models, including the non-obese diabetic (NOD) mouse model of SS. With the knowledge that VIP modulates monocyte function through vasoactive intestinal peptide receptors (VPAC) and that immune homeostasis maintenance depends strongly upon a rapid and immunosuppressant apoptotic cell clearance by monocytes/macrophages, in this study we explored VPAC expression on monocytes from primary SS (pSS) patients and the ability of VIP to modulate apoptotic cell phagocytic function and cytokine profile. Monocytes isolated from individual pSS patients showed an increased expression of VPAC2 subtype of VIP receptors, absent in monocytes from control subjects, with no changes in VPAC1 expression. VPAC2 receptor expression could be induced further with lipopolysaccharide (LPS) in pSS monocytes and VIP inhibited the effect. Moreover, monocytes from pSS patients showed an impaired phagocytosis of apoptotic epithelial cells, as evidenced by reduced engulfment ability and the failure to promote an immunosuppressant cytokine profile. However, VIP neither modulated monocyte/macrophage phagocytic function nor did it reverse their inflammatory profile. We conclude that monocytes from pSS patients express high levels of VPAC2 and display a deficient clearance of apoptotic cells that is not modulated by VIP.Fil: Hauk, Vanesa Cintia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Inmunofarmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Fraccaroli, Laura Virginia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Inmunofarmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Grasso, Esteban Nicolas. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Inmunofarmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Eimon, Alicia. Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”; ArgentinaFil: Ramhorst, Rosanna Elizabeth. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Inmunofarmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Hubscher, Osvaldo. Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”; ArgentinaFil: Perez Leiros, Claudia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Inmunofarmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

Study of functional variants of the BANK1 gene in rheumatoid arthritis

Objective. To investigate 1 functional (rs17266594) and 2 potentially functional (rs10516487 and rs3733197) BANK1 variants, which were previously identified as systemic lupus erythematosus (SLE) susceptibility markers, to test whether they are associated with rheumatoid arthritis (RA). Methods. Four different cohorts were included in the study: 1,080 RA patients and 1,368 healthy controls from Spain, 278 RA patients and 568 healthy controls from Sweden, 288 RA patients and 287 healthy controls from Argentina, and 288 RA patients and 288 healthy controls from Mexico. Samples were genotyped for BANK] single-nucleotide polymorphisms (SNPs) using a TaqMan 5'-allele discrimination assay. Statistical analysis comparing allele and genotype distributions was performed with the chi-square test. Results. We did not find a significant association between RA and the rs10516487 and rs17266594 BANK1 polymorphisms. However, there was an increase in the major alleles among RA patients. Similarly, for rs3733197, there was an increase in the major allele among patients in every cohort. Nevertheless, this skewing reached statistical significance in the Spanish (P = 0.01, odds ratio [OR] 1.17 [95% confidence interval (95% CI) 1.03-1.32]) and Argentinean (P = 0.04, OR 1.31. [95% CI 1.00-1.72]) populations. We found a significant association of rs10516487 (P = 0.005, OR 1.15 [95% CI 1.04-1.28]) and rs3733197 (P = 0.0009, OR.1.17 [95% CI 1.07-1.29]) with RA in the pooled analysis. In a 3-SNP haplotype analysis, we found that the major TGG haplotype was significantly associated with RA (P = 0.005, OR 1.14 [95% CI 1.04-1.25]). In addition, we found a common CAA haplotype that was protective against RA (P = 0.0004, OR 0.82 [95% CI 0.74-0.921). Conclusion. These results suggest that BANK1 SNPs and haplotypes may contribute to RA susceptibility with a low risk

Effects of Amerindian Genetic Ancestry on Clinical Variables and Therapy in Patients with Rheumatoid Arthritis.

To define whether Amerindian genetic ancestry correlates with clinical and therapeutic variables in admixed individuals with rheumatoid arthritis (RA) from Latin America. Patients with RA (n = 1347) and healthy controls (n = 1012) from Argentina, Mexico, Chile, and Peru were included. Samples were genotyped for the Immunochip v1 using the Illumina platform. Clinical data were obtained through interviews or the clinical history. Percentage of Amerindian ancestry was comparable between cases and controls. Morning stiffness (p Amerindian ancestry protects against most major clinical criteria of RA, but regarding the association of RF with increased European ancestry, age, sex, and smoking are modifiers. Ancestry also correlates with the therapeutic profiles

Identification of a new putative functional IL18 gene variant through an association study in systemic lupus erythematosus

Interleukin-18 (IL-18) is a proinflammatory cytokine that plays an important role in chronic inflammation and autoimmune disorders. In this study, we aimed to determine the potential role of the IL18 gene in SLE. To define the genetic association of the IL18 and SLE, we have genotyped nine SNPs in an independent set of Spanish cases and controls. The IL18 polymorphisms were genotyped by PCR, using a predeveloped TaqMan allele discrimination assay. Two SNPs were still significant after fine mapping of the IL18 gene. The SNP (rs360719) surviving correction for multiple tests was genotyped in two replication cohorts from Italy and Argentina. After the analysis, a significance with rs360719 C-allele remained across the sets and after the meta-analysis (Pooled OR 5 1.37, 95% CI 1.21-1.54, combined P 5 3.8E-07, Pc 5 1.16E-06). Quantitative real-time PCR was performed to assess IL18 mRNA expression in PBMC from subjects with different IL18 rs360719 genotypes. We tested the effect of the IL18 rs360719 polymorphism on the transcription of IL18 by electrophoretic mobility shift assay and western blot. We found a significant increase in the relative expression of IL18 mRNA in individuals carrying the rs360719 C-risk allele; in addition we show that the polymorphism creates a binding site for the transcriptional factor OCT-1. These findings suggest that the novel IL18 rs360719 variant may play an important role in determining the susceptibility to SLE and it could be a key factor in the expression of the IL18 gene. © The Author 2009. Published by Oxford University Press. All rights reserved