Effect of oxidized low-density lipoprotein on differential gene expression in primary human endothelial cells

Impact of dairy fat manipulation on endothelial function and lipid regulation in human aortic endothelial cells exposed to human plasma samples: an in vitro investigation from the RESET study

PURPOSE

Longer-term intake of fatty acid (FA)-modified dairy products (SFA-reduced, MUFA-enriched) was reported to attenuate postprandial endothelial function in humans, relative to conventional (control) dairy. Thus, we performed an in vitro study in human aortic endothelial cells (HAEC) to investigate mechanisms underlying the effects observed in vivo.

METHODS

This sub-study was conducted within the framework of the RESET study, a 12-week randomised controlled crossover trial with FA-modified and control dairy diets. HAEC were incubated for 24 h with post-intervention plasma samples from eleven adults (age: 57.5 ± 6.0 years; BMI: 25.7 ± 2.7 kg/m2) at moderate cardiovascular disease risk following representative sequential mixed meals. Markers of endothelial function and lipid regulation were assessed.

RESULTS

Relative to control, HAEC incubation with plasma following the FA-modified treatment increased postprandial NOx production (P-interaction = 0.019), yet up-regulated relative E-selectin mRNA gene expression (P-interaction = 0.011). There was no impact on other genes measured.

CONCLUSION

Incubation of HAEC with human plasma collected after longer-term dairy fat manipulation had a beneficial impact on postprandial NOx production. Further ex vivo research is needed to understand the impact of partial replacement of SFA with unsaturated fatty acids in dairy foods on pathways involved in endothelial function.

Insights Into the Role of Platelet-Derived Growth Factors: Implications for Parkinson’s Disease Pathogenesis and Treatment

Parkinson’s disease (PD), the second most common neurodegenerative disease after Alzheimer’s disease, commonly occurs in the elderly population, causing a significant medical and economic burden to the aging society worldwide. At present, there are few effective methods that achieve satisfactory clinical results in the treatment of PD. Platelet-derived growth factors (PDGFs) and platelet-derived growth factor receptors (PDGFRs) are important neurotrophic factors that are expressed in various cell types. Their unique structures allow for specific binding that can effectively regulate vital functions in the nervous system. In this review, we summarized the possible mechanisms by which PDGFs/PDGFRs regulate the occurrence and development of PD by affecting oxidative stress, mitochondrial function, protein folding and aggregation, Ca2+ homeostasis, and cell neuroinflammation. These modes of action mainly depend on the type and distribution of PDGFs in different nerve cells. We also summarized the possible clinical applications and prospects for PDGF in the treatment of PD, especially in genetic treatment. Recent advances have shown that PDGFs have contradictory roles within the central nervous system (CNS). Although they exert neuroprotective effects through multiple pathways, they are also associated with the disruption of the blood–brain barrier (BBB). Our recommendations based on our findings include further investigation of the contradictory neurotrophic and neurotoxic effects of the PDGFs acting on the CNS.

Transcriptome analysis of the Tan sheep testes: Differential expression of antioxidant enzyme-related genes and proteins in response to dietary vitamin E supplementation

Gene-chip technology was employed to study the effect of dietary vitamin E on gene expression in sheep testes based on our previous research. Thirty-five male Tan sheep (20-30 days after weaning) with similar body weight were randomly allocated into five groups and supplemented 0, 20, 100, 200 and 2,000 IU sheep(-1)day(-1) vitamin E (treatments denoted as E0, E20, E100, E200, and E2000, respectively) for 120 days. At the end of the study the sheep were slaughtered and the testis samples were immediately collected and stored in liquid nitrogen. Differences in gene expression between different treated groups were identified. Based on GO enrichment analysis and the KEGG database to evaluate the gene expression data we found that vitamin E might affect genes in the testes by modulating the oxidation level, by affecting the expression of various receptors and transcription factors in biological pathways, and by regulating the expression of metabolism-associated genes. The effect of vitamin E supplementation on the expression of oxidative enzyme-related genes was detected by quantitative real-time PCR (qRT-PCR) and Western blot. The results show that dietary vitamin E, at various doses, can significantly increase (P<0.05) the mRNA and protein expression of Glutathione peroxidase 3 and Glutathione S-transferase alpha 1. In addition, the results of qRT-PCR of the antioxidant enzyme genes were consistent with those obtained using the gene chip microarray analysis. In summary, the dietary vitamin E treatment altered the expression of a number of genes in sheep testes. The increase in the mRNA and protein levels of antioxidant enzyme genes, coupled with the elevation in the activity of the antioxidant enzymes were primarily responsible for the improved reproductive performance promoted by dietary vitamin E.

Chemical Characterization, Free Radical Scavenging, and Cellular Antioxidant and Anti-Inflammatory Properties of a Stilbenoid-Rich Root Extract of Vitis vinifera

Dietary stilbenoids are receiving increasing attention due to their potential health benefits. However, most studies concerning the bioactivity of stilbenoids were conducted with pure compounds, for example, resveratrol. The aim of this study was to characterize a complex root extract of Vitis vinifera in terms of its free radical scavenging and cellular antioxidant and anti-inflammatory properties. HPLC-ESI-MS/MS analyses of the root extract of Vitis vinifera identified seven stilbenoids including two monomeric (resveratrol and piceatannol), two dimeric (trans-ɛ-viniferin and ampelopsin A), one trimeric (miyabenol C), and two tetrameric (r-2-viniferin = vitisin A and r-viniferin = vitisin B) compounds which may mediate its biological activity. Electron spin resonance and spin trapping experiments indicate that the root extract scavenged 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, galvinoxyl, and superoxide free radicals. On a cellular level it was observed that the root extract of Vitis vinifera protects against hydrogen peroxide-induced DNA damage and induces Nrf2 and its target genes heme oxygenase-1 and γ-glutamylcysteine synthetase. Furthermore, the root extract could induce the antiatherogenic hepatic enzyme paraoxonase 1 and downregulate proinflammatory gene expression (interleukin 1β, inducible nitric oxide synthase) in macrophages. Collectively our data suggest that the root extract of Vitis vinifera exhibits free radical scavenging as well as cellular antioxidant and anti-inflammatory properties.

Modulation of Growth Factor Gene Expression in Vascular Cells by Oxidative Stress

Reactive oxygen species (ROS) generated in and around vascular endothelium may play a role in normal cellular signaling mechanisms but may also be an important causative factor in endothelial dysfunction underlying the development of atherosclerosis, diabetes complications, and ischemia-reperfusion injury. ROS influence a variety of molecular and cellular activities, including changes in the cellular localization of regulatory factors, protein modification, and altered gene expression, which in turn influence cellular phenotype. One mechanism by which ROS exert their cellular effects involves their ability to modulate the expression and function of vascular genes, such as vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and platelet-derived growth factor (PDGF), which play key atherogenic roles by their regulation of cell growth, differentiation, and fibroproliferative responsiveness. In this review the authors describe the changes induced by oxidative stress on the profile of growth factor gene expression in endothelial cells, and the impact these modifications have on endothelial phenotype as well as on the behavior of neighboring vascular smooth muscle cells and fibroblasts. The authors also discuss the involvement of redox-sensitive transcription factors in these regulatory processes.

Daily quercetin supplementation dose-dependently increases plasma quercetin concentrations in healthy humans

Our aim was to investigate the effects of an oral supplementation of quercetin at 3 different doses on plasma concentrations of quercetin, parameters of oxidant/antioxidant status, inflammation, and metabolism. To this end, 35 healthy volunteers were randomly assigned to take 50, 100, or 150 mg/d (group Q50-Q150) quercetin for 2 wk. Fasting blood samples were collected at the beginning and end of the supplementation period. Compared with baseline, quercetin supplementation significantly increased plasma concentrations of quercetin by 178% (Q50), 359% (Q100), and 570% (Q150; P < 0.01 for all). High interindividual variation was found for plasma quercetin concentrations (36-57%). Quercetin did not affect concentrations of serum uric acid or plasma alpha- and gamma-tocopherols, oxidized LDL, and tumor necrosis factor-alpha, or plasma antioxidative capacity as assessed by the ferric-reducing antioxidant potential and oxygen radical absorbance capacity assays. In addition, serum lipids and lipoproteins, body composition, and resting energy expenditure did not significantly change during quercetin supplementation. Pharmacokinetics of quercetin were investigated in a subgroup of 15 volunteers. The areas under the plasma concentration-time curves ranged from 76.1 mumol.min.L(-1) to 305.8 mumol.min.L(-1) (50- and 150-mg dosages, respectively). Median maximum plasma concentrations of quercetin (431 nmol/L) were observed 360 min after intake of 150 mg quercetin. In conclusion, daily supplementation of healthy humans with graded concentrations of quercetin for 2 wk dose-dependently increased plasma quercetin concentrations but did not affect antioxidant status, oxidized LDL, inflammation, or metabolism.

Proteome analysis suggests that mitochondrial dysfunction in stressed endothelial cells is reversed by a soy extract and isolated isoflavones

Apoptosis is a driving force in atherosclerosis development. A soy extract or a combination of the soy isoflavones genistein and daidzein inhibited apoptosis induced by oxidized LDL in endothelial cells. Proteome analysis revealed that the LDL-induced alterations of numerous proteins were reversed by the extract and the genistein/daidzein mixture but only three protein entities, all functionally linked to mitochondrial dysfunction, were regulated in common by both treatments.

Genistein affects the expression of genes involved in blood pressure regulation and angiogenesis in primary human endothelial cells

BACKGROUND

Several lines of evidence suggest that the dietary isoflavone genistein (Gen) has beneficial effects with regard to cardiovascular disease and in particular on aspects related to blood pressure and angiogenesis. The biological action of Gen may be, at least in part, attributed to its ability to affect cell signalling and response. However, so far, most of the molecular mechanisms underlying the activity of Gen in the endothelium are unknown.

METHODS AND RESULTS

To examine the transcriptional response to 2.5 microM Gen on primary human endothelial cells (HUVEC), we applied cDNA array technology both under baseline condition and after treatment with the pro-atherogenic stimulus, copper-oxidized LDL. The alteration of the expression patterns of individual transcripts was substantiated using either RT-PCR or Northern blotting. Gen significantly affected the expression of genes encoding for proteins centrally involved in the vascular tone such as endothelin-converting enzyme-1, endothelin-2, estrogen related receptor alpha and atrial natriuretic peptide receptor A precursor. Furthermore, Gen countered the effect of oxLDL on mRNA levels encoding for vascular endothelial growth factor receptor 165, types 1 and 2.

CONCLUSIONS

Our data indicate that physiologically achievable levels of Gen change the expression of mRNA encoding for proteins involved in the control of blood pressure under baseline conditions and reduce the angiogenic response to oxLDL in the endothelium.

Genistein reverses changes of the proteome induced by oxidized-LDL in EA.hy 926 human endothelial cells

Endothelial cells are primary targets for pro-atherosclerotic stressors such as oxidized LDL (ox-LDL). The isoflavone genistein, on the other hand, is suggested to prevent a variety of processes underlying atherosclerosis and cardiovascular diseases. By analyzing the proteome of EA.hy 926 endothelial cells, here we show, that genistein reverses the ox-LDL-induced changes of the steady-state levels of several proteins involved in atherosclerosis. These alterations caused by genistein are functionally linked to the inhibition of ox-LDL induced apoptosis.

Expression profiling of cardiovascular disease

Cardiovascular disease is the most important cause of morbidity and mortality in developed countries, causing twice as many deaths as cancer in the USA. The major cardiovascular diseases, including coronary artery disease (CAD), myocardial infarction (MI), congestive heart failure (CHF) and common congenital heart disease (CHD), are caused by multiple genetic and environmental factors, as well as the interactions between them. The underlying molecular pathogenic mechanisms for these disorders are still largely unknown, but gene expression may play a central role in the development and progression of cardiovascular disease. Microarrays are high-throughput genomic tools that allow the comparison of global expression changes in thousands of genes between normal and diseased cells/tissues. Microarrays have recently been applied to CAD/MI, CHF and CHD to profile changes in gene expression patterns in diseased and non-diseased patients. This same technology has also been used to characterise endothelial cells, vascular smooth muscle cells and inflammatory cells, with or without various treatments that mimic disease processes involved in CAD/MI. These studies have led to the identification of unique subsets of genes associated with specific diseases and disease processes. Ongoing microarray studies in the field will provide insights into the molecular mechanism of cardiovascular disease and may generate new diagnostic and therapeutic markers.

Genetics, genomics and proteomics in atherosclerosis research

Atherosclerosis and its clinical manifestations are the leading cause of death in Western countries. Atherosclerosis is a multifactorial disease characterized by endothelial dysfunction, smooth muscle cell (SMC) proliferation and migration, inflammation, lipid and matrix accumulation and thrombus formation. Multiple genetic and environmental features and interactions between these factors influence the disease process. To understand fundamental pathobiological mechanisms in atherogenesis and to develop and target new therapies, information on genetic factors (atherogenetics), gene expression patterns (atherogenomics) and protein expression patterns (atheroproteomics) are needed. This review will summarize current knowledge in these areas of atherosclerosis research with a special emphasis on microarray technology.

Identification of hepatic molecular mechanisms of action of alpha-tocopherol using global gene expression profile analysis in rats

The recent discovery that vitamin E (VE) regulates gene activity at the transcriptional level indicates that VE may exert part of its biological effects by mechanisms which may be independent of its well-recognised antioxidant function. The objective of this study was the identification of hepatic vitamin E-sensitive genes and examination of the effects of VE on their corresponding biological endpoints. Two groups of male rats were randomly assigned to either a VE-sufficient diet or to a control diet deficient in VE for 290 days. High-density oligonucleotide microarrays comprising over 7000 genes were used to assess the transcriptional response of the liver. Differential gene expression was monitored over a period of 9 months, at four different time-points, and rats were individually profiled. This experimental strategy identified several VE-sensitive genes, which were chronically altered by dietary VE. VE supplementation down-regulated scavenger receptor CD36, coagulation factor IX and 5-alpha-steroid reductase type 1 mRNA levels while hepatic gamma glutamyl-cysteinyl synthetase was significantly up-regulated. Measurement of the corresponding biological endpoints such as activated partial thromboplastin time, plasma dihydrotestosterone and hepatic glutathione substantiated the gene chip data which indicated that dietary VE plays an important role in a range of metabolic processes within the liver.