Influence of endothelial nitric oxide synthase haplotypes on nitric oxide and peroxynitrite productions

The impact of four clinically significant genetic variants of endothelial nitric oxide synthase (eNOS) polymorphisms on the concentrations of nitric oxide [NO] and peroxynitrite [ONOO^-] has been given scant consideration. This study utilized a [NO]/[ONOO^-] ratio to determine the extent of endothelial dysfunction caused by these variations in the eNOS gene. The single nucleotide polymorphisms (T-786C, C-665T, and Glu298Asp) and a variable number of tandem repeats (intron 4 a/b/c) were genotyped in human umbilical vein endothelial cells (HUVEC), using sanger sequencing and DNA electrophoresis, respectively. Nanosensors were used to determine the maximal [NO] and [ONOO^-], while traditional and low-temperature SDS-PAGE were used to evaluate the expression of eNOS and the eNOS dimer-to-monomer ratio, respectively. The study results indicate that the eNOS haplotype H3 (G T/C C 4a/c allele) may have a protective effect against cardiovascular disease (CVD) with the [NO]/[ONOO^-] ratio higher than 2. However, the eNOS haplotypes H2 (G T/C C 4a/b) and H5 (T T/C C 4b) increase the susceptibility to CVD with [NO]/[ONOO^-] ratio lower than 1. The results suggest that certain eNOS genetic variants may influence susceptibility to cardiovascular disease (CVD) while other variants may have a protective effect.