Polymorphism −2604G>A variants in TLR4 promoter are associated with different gene expression level in peripheral blood of atherosclerotic patients

Toll-like receptor-4 (TLR4) is a primary receptor of the innate immune reaction and compelling evidence demonstrates its involvement in the pathogenesis of atherosclerosis and stroke. TLR4 is constitutively expressed on monocytes and endothelial cells; it is highly expressed in atherosclerotic plaques and in peripheral blood of patients after ischemic stroke. Polymorphisms in the promoter region that alter the transcriptional regulation of this gene may represent genetic risk factors involved in the predisposition to atherosclerotic disease. In this study we investigated the effect on TLR4 gene expression of three polymorphisms in the upstream regulatory region at positions −1607T>C/rs10759932, −2026A>G/rs1927914 and −2604G>A/rs10759931 in peripheral blood of atherosclerotic patients. RNA from individuals homozygous for the −2604A allele showed a lower expression of the gene when compared to patients carrying the counterparts GG+GA. Electrophoretic mobility shift assays showed differences in the electrophoretic mobility of the DNA–nuclear protein complexes formed by the G>A variants, suggesting that the two alleles differ in their binding affinity to transcriptional factors.