P98	Genotype-dependent NOS-3 expression and rheumatoid arthritis.
1M.Cattaruzza, 2I.Melchers, 1M.Hecker
1Institute of Physiology and Pathophysiology, Heidelberg, DE; 2Clinical Research Unit for Rheumatology, Freiburg, DE.

Background The hochgestellt(-786)C-variant of the human endothelial nitric oxide synthase (nos-3) gene is associated with coronary artery disease because of a blunted inducibility of gene expression. Interleukin-10 (IL-10) is involved in T tiefgestellt(H1)/T tiefegstellt(H2)-cell differentiation and for this involvement is thought to slow down T tiefgestellt(H1)-mediated diseases. As it has been recently shown that IL-10 also stimulates endothelial NOS-3 expression, we here address the question whether IL-10-induced NOS-3 expression is decreased in individuals with hochgestellt(-786)C/C genotype and if so, whether the TH1-mediated disease rheumatoid arthritis is associated with this genotype. Methods Endothelial cells were isolated and cultured from single human umbilical veins (HUVEC) and used as primary cells. NOS-3 expression was quantitatively analysed by real time RT-PCR. HUVEC and Patients blood were genotyped for the nos-3 hochgestellt(-786)C/T single nucleotide polymorphism. Patients donating blood after informed consent met the revised criteria of the ACR for the rheumatoid arthritis classification. Results HUVEC with hochgestellt(-786)C/C genotype did not respond with an increase in NOS-3 expression to IL-10 (5 ng/mL) and IL-10 did not suppress CD40-induced interleukin-12 expression in these cells. Pre-incubation of hochgestellt(-786)C/C HUVEC with decoy-oligonucleotides (10 mmol/L) comprising position -794 to -779 of the C-type nos-3 promoter reconstituted IL-10-mediated NOS-3 expression and IL-12 suppression. Among 615 patients with rheumatoid arthritis incidences for the hochgestellt(-786)C/C genotype were significantly higher as in the general population (18.9% vs. 11.7%; *P=0.0005). Conclusion NOS-3 mediates anti-inflammatory IL-10-actions in endothelial cells. Individuals with hochgestellt(-786)C/C nos-3-genotype have an increased risk for the development of rheumatoid arthritis. This might be due to the IL-10-insensitivity of the C-variant of the promoter.

Copyright © 2005 S. Karger AG, Basel. Any further use of this abstract requires written permission from the publisher.