Effects of dietary polyphenols on gene expression in human vascular endothelial cells

Abstract

Previous studies have shown that consumption of fruit and vegetables plays a role in preventing the onset of CVD. These beneficial effects have been linked to the presence of polyphenolic compounds in plant-derived foods and their antioxidant capacity. It has been hypothesised that polyphenols may also have a direct effect on vascular endothelial cell growth and the expression of genes involved in angiogenesis and other roles of the endothelium. Previous studies in this area have tended to use concentrations of polyphenols that are supraphysiological (1-100 mM). The effects of more physiological concentrations (0 . 1 mM) of various individual polyphenols on gene expression were therefore investigated in cultured human umbilical vein endothelial cells (HUVEC) using both microarray and quantitative RT-PCR methodologies. Treatment of HUVEC with ferulic acid, quercetin or resveratrol (0 . 1 mM) resulted in changes to gene expression that for the three treatments amounted to significant ( > 2-fold) down-regulation of the expression of 363 genes and significant ( > 2-fold) up-regulation of 233 genes of the 10 000 genes present on the microarray. The majority of these genes were affected by resveratrol. Quantitative RT-PCR studies indicated that resveratrol (0 . 1 mM) significantly increased the expression of the gene encoding endothelial NO synthase (eNOS), which synthesises the vasodilator molecule NO, and both resveratrol and quercetin decreased expression of the potent vasoconstrictor, endothelin-1 (ET-1), while ferulic acid had no effect. The effects of resveratrol (0 . 1 mM) were also investigated when HUVEC were under oxidative stress following treatment with H 2 O 2 (0-50 mM), which dose-dependently increased expression of eNOS and ET-1. Resveratrol stimulated eNOS mRNA in the absence of H 2 O 2 and still allowed the increase with H 2 O 2 , but the effects were not additive. In contrast, resveratrol blocked the stimulatory effect of H 2 O 2 on ET-1 expression. Hence, resveratrol has potent effects at a physiological concentration (0 . 1 mM) that would be expected to result in vasodilation and therefore help reduce blood pressure and the risk of CVD. Polyphenols: Human umbilical vein endothelial cells: Gene expressionIn the UK there was a dramatic increase in the incidence rates of CVD such as CHD and atherosclerosis during the 20th century up to the end of the 1970s (1) . Although the numbers of deaths from these diseases are currently decreasing within the UK population, CVD are still the main cause of death in the UK, and the incidence rates of CVD are on the increase worldwide. In 2005 CVD was the main cause of morbidity in the UK, resulting in 208 229 deaths, with CHD accounting for 48 . 5% of these cases (1) . Thus, efforts are being made to identify methods for both the prevention and the treatment of CVD to further reduce the rate of incidence of these diseases within both the UK population and worldwide.

The Effects of Chronic Resveratrol Treatment on Vascular Responsiveness of Streptozotocin-Induced Diabetic Rats

“…14) Resveratrol significantly increased the expression of the gene encoding eNOS, which synthesis the vasodilator molecule NO, and decreased expression of the potent vasoconstrictor, endothelin-1 (ET-1). 15) Resveratrol reduces the generation of H 2 O 2 and normalizes the levels of oxidized glutathione reductase and myeloperoxidase (MPO) activities. By normalization of the reductive oxygen species (ROS) levels, resveratrol limits the oxidative stress, which inhibits NO synthesis by eNOS necessary for vasorelaxation.…”

The Inhibitory Effect of Quercetin on the Agonist-Induced Regulation of Vascular Contractility

“…Interestingly, the mechanism involved seems to be not only endothelium-dependent but also to involve the inhibition of Rho-kinase and the partial inhibition of MEK activity. It has been reported that the health benefi ts of quercetin include relief of menopausal symptoms, lower plasma cholesterol levels, a reduction in the risks of certain hormone-related cancers, enhanced endothelium-dependent vasorelaxation (Nicholson et al, 2008;Khoo et al, 2010) and a reduced risk of cardiovascular disease due to its anti-atherosclerotic properties (Zang et al, 2006). Although these effects of quercetin suggest that it could protect against vascular disease, the mechanism involved seems to be primarily endothelium-dependent and it is known to be defi cient in several adult or metabolic diseases such as hypertension or diabetes.…”

“…It is possible that the contractions induced by fl uoride involve the RhoA/Rho-kinase pathway (Jeon et al, 2006). However, it has not been reported as to whether this pathway is inhibited during quercetin-induced vascular smooth muscle relaxation in aortic rings precontracted with Rho-kinase activator fl uoride or phorbol ester primarily attributing to endothelial nitric oxide synthesis (Nicholson et al, 2008;Khoo et al, 2010). Therefore, the aim of the present study was to investigate the possible roles of Rho-kinase or MEK inhibition on Ca 2+ desensitization during the quercetininduced relaxation of isolated rat aortas by using RhoA/Rhokinase activators such as a full activator thromboxane A 2 or a partial activator phorbol ester excluding endothelial nitric oxide synthesis.…”

“…lished (Nicholson et al, 2008;Khoo et al, 2010). Furthermore, endothelial dysfunction is known to contribute to the pathophysiologies of conditions like hypertension or diabetes.…”

Porcine Aortic Endothelial Cell Genes Responsive to Selected Inflammatory Stimulators

“…In xenotransplantaion with porcine tissues, porcine endothelial cells become activated by human cytokines such as TNF-. Gene expression changes induced by human cytokines in human endothelial cells have been extensively studied [1,6,24,29]. In this study we established porcine endothelial cell lines that lack surface expression of VCAM1 and thus mimic endothelial cells in quiescent resting status.…”