A promoter polymorphism of the endothelial nitric oxide synthase gene is associated with reduced mRNA and protein expression in failing human myocardium.
BACKGROUND
Alterations of endothelial nitric oxide synthase (eNOS) enzyme activity via eNOS gene polymorphisms have been associated with significant cardiovascular morbidity and mortality. Both the thymidine to cytosine transition mutation (T(-786)-->C) in the promoter region and the missense mutation in the exon 7 coding region of the eNOS gene (G(894)-->T) have been associated with several cardiovascular disease states. We hypothesized that heart transplant recipients who carried at least 1 allele of either of the polymorphisms would have reduced myocardial tissue expression of eNOS measured in the explanted heart.


RESULTS
Genomic DNA was isolated from myocardial tissue samples obtained from 43 explanted human hearts using standard methods. Regions of the eNOS gene were amplified from genomic DNA with a polymerase chain reaction using specific primers. Protein expression of eNOS was measured by Western blot analysis. There was a statistically significant decrease in mean eNOS expression in samples containing at least one allele for the T(-786)-->C promoter polymorphism (P=.04) compared with patients homozygous for the T allele. There was no change in eNOS expression associated with the G(894)-->T exonic polymorphisms.


CONCLUSIONS
Our data show in failing human myocardium that the T(-786)-->C promoter polymorphism is associated with reduced eNOS expression, whereas the G(894)-->T polymorphism of exon 7 is not associated with change in either eNOS mRNA or protein expression. Reduced eNOS expression associated with the promoter polymorphism may contribute to the vascular, contractile, and autonomic responses to ventricular failure.
Doshi
Amit A
AA
Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH 43210, USA.
Ziolo
Mark T
MT
Wang
Honglan
H
Burke
Emily
E
Lesinski
Amanda
A
Binkley
Philip
P
D000328:Adult; D003597:Cytosine Nucleotides / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D006333:Heart Failure / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology*; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D013942:Thymine Nucleotides / Q000235:genetics
D003597:Cytosine Nucleotides; D012333:RNA, Messenger; D013942:Thymine Nucleotides; D052250:Nitric Oxide Synthase Type III