Endothelial nitric oxide synthase polymorphism G298T in association with oxidative DNA damage in coronary atherosclerosis

Histone Methylation Related Therapeutic Challenge in Cardiovascular Diseases

The epidemic of cardiovascular diseases (CVDs) is predicted to spread rapidly in advanced countries accompanied by the high prevalence of risk factors. In terms of pathogenesis, the pathophysiology of CVDs is featured by multiple disorders, including vascular inflammation accompanied by simultaneously perturbed pathways, such as cell death and acute/chronic inflammatory reactions. Epigenetic alteration is involved in the regulation of genome stabilization and cellular homeostasis. The association between CVD progression and histone modifications is widely known. Among the histone modifications, histone methylation is a reversible process involved in the development and homeostasis of the cardiovascular system. Abnormal methylation can promote CVD progression. This review discusses histone methylation and the enzymes involved in the cardiovascular system and determine the effects of histone methyltransferases and demethylases on the pathogenesis of CVDs. We will further demonstrate key proteins mediated by histone methylation in blood vessels and review histone methylation-mediated cardiomyocytes and cellular functions and pathways in CVDs. Finally, we will summarize the role of inhibitors of histone methylation and demethylation in CVDs and analyze their therapeutic potential, based on previous studies.

Association Between Endothelial Nitric Oxide Synthase (eNOS) -786 T/C and 27-bp VNTR 4b/a Polymorphisms and Preeclampsia Development

The aim of the present study was to analyze the distribution of genotypes and haplotypes of functional eNOS gene polymorphisms in the promoter (-786 T/C), intron 4 (VNTR4b/a) and exon 7 (894 G/T), in Serbian population of pregnant women, and establish a possible association between these polymorphisms and preeclampsia development. DNA was isolated from venous blood samples of 50 heathy pregnant women and 50 preeclampsia patients. Polymerase Chain Reaction/Restriction Fragment Length Polymorphism (PCR/RFLP) technique, with appropriate sets of primers and specific restriction enzymes, was used to determine polymorphisms in eNOS gene. Statistical analysis was done using the SPSS and HAPLOVIEW software packages. eNOS -786 T/C polymorphism was significantly associated with preeclampsia (P = 0.006). Homozygotes for the VNTR polymorphism had also an elevated risk of developing preeclampsia (OR=7.68, 95%CI (0.89-65.98)), especially the mild (OR=9.33, 95%CI (0.98-88.57)) and late form (OR=8.52, 95%CI (0.90-80.58)). The 894 G/T polymorphism was not associated with preeclampsia. "G-C-b" and "T-4a-T" haplotypes were more frequent in preeclampsia, though without reaching statistical significance. -786 T/C and VNTR 4b/a eNOS gene polymorphisms were associated with preeclampsia risk in Serbian patients.

Genetic association between eNOS gene polymorphisms and risk of carotid atherosclerosis : A meta-analysis

BACKGROUND

Endothelial nitric oxide synthase (eNOS) has been reported to be involved in the atherosclerotic process. A number of studies have investigated the association between eNOS gene polymorphisms and the risk of carotid atherosclerosis (CAS). However, the results are conflicting and inconclusive. The aim of this study was to evaluate precisely the association between the eNOS T786C, G894T, and 4a/4b polymorphisms and CAS risk.

MATERIAL AND METHODS

A meta-analysis was carried out by retrieving relevant studies from PubMed, Embase, China National Knowledge Infrastructure (CNKI), and Cochrane databases without a restriction on publication year. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to describe the strength of the association with CAS.

RESULTS

Data were obtained from eight case-control studies comprising 2975 cases and 2624 controls. Significant associations were detected between the allelic and recessive models of the eNOS T786C polymorphism (allelic: p = 0.04; OR, 95% CI = 1.57 [1.01, 2.44]; recessive: p = 0.03; OR, 95% CI = 1.53 [1.04, 2.24]), as well as the allelic and dominant models of the eNOS 4a/4b polymorphism, and CAS risk in an Asian subgroup (allelic: p = 0.02; OR, 95% CI = 1.49 [1.07, 2.07]; dominant: p = 0.01; OR, 95% CI = 1.50 [1.09, 2.05]), but not in a Caucasian subgroup (p > 0.05). No association was observed between the eNOS G894T polymorphism and CAS risk (p > 0.05).

CONCLUSION

Our study provides evidence that the allelic and recessive models of the eNOS T786C polymorphism and the allelic and dominant models of the eNOS 4a/4b polymorphism may increase the risk of CAS in Asian populations.

Heme oxygenase-1 ameliorates oxidative stress-induced endothelial senescence via regulating endothelial nitric oxide synthase activation and coupling

AIM

Premature senescence of vascular endothelial cells is a leading cause of various cardiovascular diseases. Therapies targeting endothelial senescence would have important clinical implications. The present study was aimed to evaluate the potential of heme oxygenase-1 (HO-1) as a therapeutic target for endothelial senescence.

METHODS AND RESULTS

Upregulation of HO-1 by Hemin or adenovirus infection reversed H₂O₂-induced senescence in human umbilical vein endothelial cells (HUVECs); whereas depletion of HO-1 by siRNA or HO-1 inhibitor protoporphyrin IX zinc (II) (ZnPP) triggered HUVEC senescence. Mechanistically, overexpression of HO-1 enhanced the interaction between HO-1 and endothelial nitric oxide synthase (eNOS), and promoted the interaction between eNOS and its upstream kinase Akt, thus resulting in an enhancement of eNOS phosphorylation at Ser1177 and a subsequent increase of nitric oxide (NO) production. Moreover, HO-1 induction prevented the decrease of eNOS dimer/monomer ratio stimulated by H₂O₂ via its antioxidant properties. Contrarily, HO-1 silencing impaired eNOS phosphorylation and accelerated eNOS uncoupling. In vivo, Hemin treatment alleviated senescence of endothelial cells of the aorta from spontaneously hypertensive rats, through upregulating eNOS phosphorylation at Ser1177.

CONCLUSIONS

HO-1 ameliorated endothelial senescence through enhancing eNOS activation and defending eNOS uncoupling, suggesting that HO-1 is a potential target for treating endothelial senescence.