Open AccessThe –786 C/T single‐nucleotide polymorphism in the promoter of the gene for endothelial nitric oxide synthase: Insensitivity to physiologic stimuli as a risk factor for rheumatoid arthritis
Author(s) -
Melchers Inga,
Blaschke Sabine,
Hecker Markus,
Cattaruzza Marco
Publication year - 2006
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.22147
Subject(s) - single nucleotide polymorphism , microbiology and biotechnology , genotype , biology , nitric oxide synthase , cytokine , gene expression , gene , promoter , immunology , medicine , endocrinology , nitric oxide , genetics
Objective Shear stress is the main physiologic stimulus for the expression of NOS3 , the gene for human endothelial nitric oxide synthase. Interestingly, a promoter variant of the NOS3 gene, the –786 C variant, is insensitive to shear stress, and individuals homozygous for this single‐nucleotide polymorphism (SNP) have an increased risk of developing coronary artery disease. The cytokine interleukin‐10 (IL‐10) is also capable of up‐regulating endothelial NOS3 expression through binding of the transcription factor STAT‐3 to a nearby promoter sequence. The aim of this study was to explore the possibility that the –786 C variant of the NOS3 gene is also insensitive to IL‐10 and that individuals with the –786 C/C genotype are more prone to developing rheumatoid arthritis (RA). Methods Endothelial cells were isolated from human umbilical cord veins, clonally expanded, and analyzed for NOS3 and IL‐12 expression by real‐time quantitative reverse transcription–polymerase chain reaction and enzyme‐linked immunosorbent assay. Umbilical cord arteries and blood samples from RA patients were genotyped for the –786 C/T SNP of the NOS3 gene. Results In contrast to cells of other genotypes, endothelial cells of the –786 C/C genotype did not reveal an increase in NOS3 expression upon exposure to IL‐10, and the cytokine failed to suppress IL‐12 expression upon stimulation of CD40. Preincubation of these cells with a 16‐mer C‐type decoy oligonucleotide fully reconstituted the defective IL‐10–induced suppression of IL‐12 synthesis. The frequency of the –786 C/C genotype was significantly higher in the 596 RA patients than in the general population (19.1% versus 12.1%; P < 0.0001). Conclusion Individuals with the –786 C/C genotype have an increased risk of developing RA. This may be explained by the IL‐10 insensitivity of the C‐type NOS3 gene promoter and the resulting failure to subdue CD40‐mediated proinflammatory gene expression.