Proteome analysis for identification of target proteins of genistein in primary human endothelial cells stressed with oxidized LDL or homocysteine

Background Epidemiological studies suggest that soy consumption contributes to the prevention of coronary heart disease. The proposed anti-atherogenic effects of soy appear to be carried by the soy isoflavones with genistein as the most abundant compound. Aim of the study To identify proteins or pathways by which genistein might exert its protective activities on atherosclerosis, we analyzed the proteomic response of primary human umbilical vein endothelial cells ( HUVEC) that were exposed to the pro-atherosclerotic stressors homocysteine or oxidized low-density lipoprotein (ox-LDL). Methods HUVEC were incubated with physiological concentrations of homocysteine or ox-LDL in the absence and presence of genistein at concentrations that can be reached in human plasma by a diet rich in soy products (2.5 muM) or by pharmacological intervention ( 25 muM). Proteins from HUVEC were separated by two-dimensional polyacrylamide gel electrophoresis and those that showed altered expression level upon genistein treatment were identified by peptide mass fingerprints derived from tryptic digests of the protein spots. Results Several proteins were found to be differentially affected by genistein. The most interesting proteins that were potently decreased by homocysteine treatment were annexin V and lamin A. Annexin V is an antithrombotic molecule and mutations in nuclear lamin A have been found to result in perturbations of plasma lipids associated with hypertension. Genistein at low and high concentrations reversed the stressor-induced decrease of these anti-atherogenic proteins. Ox-LDL treatment of HUVEC resulted in an increase in ubiquitin conjugating enzyme 12, a protein involved in foam cell formation. Treatment with genistein at both doses reversed this effect. Conclusions Proteome analysis allows the identification of potential interactions of dietary components in the molecular process of atherosclerosis and consequently provides a powerful tool to define biomarkers of response.

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 mu M 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, endothetin-2, estrogen related receptor a and atria[ 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. (c) 2005 Elsevier B.V. All rights reserved.

Increased levels of microparticles originating from endothelial cells, platelets and erythrocytes in subjects with metabolic syndrome: relationship with oxidative stress

Background and aims The Metabolic Syndrome (MetS) is associated with increased cardiovascular risk. Circulating microparticles (MP) are involved in the pathogenesis of atherothrombotic disorders and are raised in individual with CVD. We measured their level and cellular origin in subjects with MetS and analyzed their associations with 1/anthropometric and biological parameters of MetS, 2/inflammation and oxidative stress markers. Methods and results Eighty-eight subjects with the MetS according to the NCEP-ATPIII definition were enrolled in a bicentric study and compared to 27 healthy controls. AnnexinV-positive MP (TMP), MP derived from platelets (PMP), erythrocytes (ErMP), endothelial cells (EMP), leukocytes (LMP) and granulocytes (PNMP) were determined by flow cytometry. MetS subjects had significantly higher counts/μl of TMP (730.6 ± 49.7 vs 352.8 ± 35.6), PMP (416.0 ± 43.8 vs 250.5 ± 23.5), ErMP (243.8 ± 22.1 vs 73.6 ± 19.6) and EMP (7.8 ± 0.8 vs 4.0 ± 1.0) compared with controls. LMP and PNMP were not statistically different between groups. Multivariate analysis demonstrated that each criterion for the MetS influenced the number of TMP. Waist girth was a significant determinant of PMP and EMP level and blood pressure was correlated with EMP level. Glycemia positively correlated with PMP level whereas dyslipidemia influenced EMP and ErMP levels. Interestingly, the oxidative stress markers, plasma glutathione peroxydase and urinary 8-iso-prostaglandin F2 α, independently influenced TMP and PMP levels whereas inflammatory markers did not, irrespective of MP type. Conclusion Increased levels of TMP, PMP, ErMP and EMP are associated with individual metabolic abnormalities of MetS and oxidative stress. Whether MP assessment may represent a marker for risk stratification or a target for pharmacological intervention deserves further investigation.

Hypoxic modulation of ca(2+) signaling in human venous and arterial endothelial cells

Our understanding of vascular endothelial cell physiology is based on studies of endothelial cells cultured from various vascular beds of different species for varying periods of time. Systematic analysis of the properties of endothelial cells from different parts of the vasculature is lacking. Here, we compare Ca(2+) homeostasis in primary cultures of endothelial cells from human internal mammary artery and saphenous vein and how this is modified by hypoxia, an inevitable consequence of bypass grafting (2.5% O(2), 24 h). Basal [Ca(2+)]( i ) and store depletion-mediated Ca(2+) entry were significantly different between the two cell types, yet agonist (ATP)-mediated mobilization from endoplasmic reticulum stores was similar. Hypoxia potentiated agonist-evoked responses in arterial, but not venous, cells but augmented store depletion-mediated Ca(2+) entry only in venous cells. Clearly, Ca(2+) signaling and its remodeling by hypoxia are strikingly different in arterial vs. venous endothelial cells. Our data have important implications for the interpretation of data obtained from endothelial cells of varying sources.

Comparative effect of dairy fatty acids on cell adhesion molecules, nitric oxide and relative gene expression in healthy and diabetic human aortic endothelial cells

Dairy intake, despite its high saturated fatty acid (SFA) content, is associated with a lower risk of cardiovascular disease and diabetes. This in vitro study determined the effect of individual fatty acids (FA) found in dairy, and FA mixtures representative of a high SFA and a low SFA dairy lipid on markers of endothelial function in healthy and type II diabetic aortic endothelial cells.

Syk and Src family kinases regulate C-type lectin receptor 2 (CLEC-2)-mediated clustering of podoplanin and platelet adhesion to lymphatic endothelial cells

The interaction of C-type lectin receptor 2 (CLEC-2) on platelets with Podoplanin on lymphatic endothelial cells initiates platelet signaling events that are necessary for prevention of blood-lymph mixing during development. In the present study, we show that CLEC-2 signaling via Src family and Syk tyrosine kinases promotes platelet adhesion to primary mouse lymphatic endothelial cells at low shear. Using supported lipid bilayers containing mobile Podoplanin, we further show that activation of Src and Syk in platelets promotes clustering of CLEC-2 and Podoplanin. Clusters of CLEC-2-bound Podoplanin migrate rapidly to the center of the platelet to form a single structure. Fluorescence lifetime imaging demonstrates that molecules within these clusters are within 10 nm of one another and that the clusters are disrupted by inhibition of Src and Syk family kinases. CLEC-2 clusters are also seen in platelets adhered to immobilized Podoplanin using direct stochastic optical reconstruction microscopy. These findings provide mechanistic insight by which CLEC-2 signaling promotes adhesion to Podoplanin and regulation of Podoplanin signaling, thereby contributing to lymphatic vasculature development.

p22phox C242T SNP inhibits inflammatory oxidative damage to endothelial cells and vessels

Background— T NADPH oxidase, by generating reactive oxygen species, is involved in the pathophysiology of many cardiovascular diseases and represents a therapeutic target for the development of novel drugs. A single-nucleotide polymorphism (SNP) C242T of the p22phox subunit of NADPH oxidase has been reported to be negatively associated with coronary heart disease (CHD) and may predict disease prevalence. However, the underlying mechanisms remain unknown. Methods and Results— Using computer molecular modelling we discovered that C242T SNP causes significant structural changes in the extracellular loop of p22phox and reduces its interaction stability with Nox2 subunit. Gene transfection of human pulmonary microvascular endothelial cells showed that C242T p22phox reduced significantly Nox2 expression but had no significant effect on basal endothelial O2.- production or the expression of Nox1 and Nox4. When cells were stimulated with TNFα (or high glucose), C242T p22phox inhibited significantly TNFα-induced Nox2 maturation, O2.- production, MAPK and NFκB activation and inflammation (all p<0.05). These C242T effects were further confirmed using p22phox shRNA engineered HeLa cells and Nox2-/- coronary microvascular endothelial cells. Clinical significance was investigated using saphenous vein segments from non CHD subjects after phlebectomies. TT (C242T) allele was common (prevalence of ~22%) and compared to CC, veins bearing TT allele had significantly lower levels of Nox2 expression and O2.- generation in response to high glucose challenge. Conclusions— C242T SNP causes p22phox structural changes that inhibit endothelial Nox2 activation and oxidative response to TNFα or high glucose stimulation. C242T SNP may represent a natural protective mechanism against inflammatory cardiovascular diseases.

Melatonin inhibits LPS-induced NO production in rat endothelial cells

Endothelial cells produce NO by activation of constitutive nitric oxide synthase (NOS) and transcription of inducible NOS (iNOS). We have previously shown that melatonin, in the nanomolar range, inhibits activation of constitutive NOS, and in the present paper, we evaluated whether it could interfere with the expression of iNOS, which is activated by lipopolysaccharide (LPS), a major component of gram-negative bacteria cell walls. Primary cultures of rat endothelial cells were loaded with fluorescent probe for NO detection. Nuclear factor kappa B (NF-kappa B) translocation in endothelial cells elicited by LPS was measured by electromobility shift assay, and the vasodilation of aortic rings was accessed by recording isometric contraction. Melatonin in a micromolar but not in a nanomolar range inhibits the NO production induced by LPS. This effect is not dependent on the activation of G protein-coupled melatonin receptors. The nuclear NF-kappa B translocation is a process necessary for iNOS transcription, and melatonin also inhibits its translocation. LPS induced vasodilation only in endothelium-intact aortic rings, and melatonin (10 mu m) inhibits the vasodilation. Here, we show that concentrations compatible with nocturnal melatonin surge (nm) did not interfere with the activity of iNOS. Considering that micromolar melatonin concentrations could be locally achieved through production by activated immune competent cells, extra-pineal melatonin could have a protective effect against tissue injury. We propose that melatonin blocked the LPS-induced vasodilation by inhibiting the NF-kappa B pathway. Finally, we propose that the effect of melatonin on vascular reactivity is one of the mechanisms that underlies the protective effect of this indolamine against LPS.

Proinsulin C-peptide induces c-Jun N-terminal kinase 1 expression in LEII mouse lung capillary endothelial cells

To characterize the roles of C-peptide in vascular homeostatic processes, we examined the genes regulated by C-peptide in LEII mouse lung microvascular endothelial cells. Treatment of the cells with C-peptide increased the expression of c-Jun N-terminal kinase 1 (JNK1) mRNA dose-dependently, accompanied by an increase in JNK1 protein content. Prior treatment of the cells with PD98059, an ERK kinase inhibitor or SB203580, a p38MAPK inhibitor, abrogated the C-peptide-elicited JNK1 mRNA expression. These results indicate that C-peptide increases JNK1 protein levels, possibly through ERK- and p38MAPK-dependent activation of JNK. gene transcription.

Putative outer membrane proteins of Leptospira interrogans stimulate human umbilical vein endothelial cells (HUVECS) and express during infection

Cell adhesion molecules (CAMs) are surface receptors present in eukaryotic cells that mediate cell-cell or cell-extracellular matrix interactions. Vascular endothelium stimulation in vitro that lead to the upregulation of CAMs was reported for the pathogenic spirochaetes, including rLIC10365 of Leptospira interrogans. In this study, we report the cloning of LIC10507, LIC10508, LIC10509 genes of L interrogans using Escherichia coli as a host system. The rational for selecting these sequences is due to their location in L. interrogans serovar Copenhageni genome that has a potential involvement in pathogenesis. The genes encode for predicted lipoproteins with no assigned functions. The purified recombinant proteins were capable to promote the upregulation of intercellular adhesion molecule 1 (ICAM-1) and E-selectin on monolayers of human umbilical vein endothelial cells (HUVECS). In addition, the coding sequences are expressed in the renal tubules of animal during bacterial experimental infection. The proteins are probably located at the outer membrane of the bacteria since they are detected in detergent-phase of L interrogans Triton X-114 extract. Altogether our data suggest a possible involvement of these proteins during bacterial infection and provide new insights into the role of this region in the pathogenesis of Leptospira. (C) 2008 Elsevier Ltd. All rights reserved.

Differential vascular adaptive response to stress exposure in male and female rats: Role of gonadal hormones and endothelial cells

Although there are reports concerning a vascular adaptive response to stress in males, this is not yet defined in females. The aim of this study was to delineate functional gender differences in the rat vascular adaptive response to stress and to determine the ability of sex hormones to modulate the stress-induced vascular adaptive response. Responses to noradrenaline were evaluated in aortas, with and without endothelium, from intact, gonadectomized and gonadectomized-hormone-replaced males and females submitted or not to stress (2-h immobilization). Reactivity of the aorta of stressed and non-stressed intact males and females (n = 6-14 per group) was also examined in the presence of L-NAME or indomethacin. Stress decreased and gonadectomy increased maximal responses to noradrenaline in aortas with intact endothelium from both genders. Stress also reduced noradrenaline potency in males. In females, but not males, stress decreased the gonadectomy-induced noradrenaline hyper-reactivity to near that of intact non-stressed rats. Hormone replacement restored the gonadectomy-induced impaired vascular adaptive response to stress. L-NAME, but not indomethacin, abolished the stress-induced decrease in aorta reactivity of males and females. None of the procedures altered reactivity of aortas denuded of endothelium. Conclusion: Stress-induced vascular adaptive responses show gender differences. The magnitude of the adaptive response is dependent on testicular hormones and involves endothelial nitric oxide-system hyperactivity.

Interaction of human neutrophils with endothelial cells regulates the expression of endogenous proteins annexin 1, galectin-1 and galectin-3

Annexin 1 (ANXA1), galectin-1 (Gal-1) and galectin-3 (Gal-3) proteins have been identified as important mediators that promote or inhibit leukocyte migration. The expression of these proteins was studied in human neutrophils and endothelial cells (ECs) during a transmigration process induced by IL-8. Upon neutrophil adhesion to EC, a significant increase in the cleaved ANXA1 (LCS3, raised against all ANXA1 isoforms) expression was detected in the plasma membrane of adhered neutrophils and ECs compared to intact ANXA1 isoform (LCPS1, against N-terminus of protein). Adherent neutrophils had elevated Gal-3 levels in the nucleus and cytoplasm, and ECs in their plasma membranes. In contrast, a decrease in the total amounts of Gal-1 was detected in migrated compared to non-migrated neutrophils. Therefore, ANXA1 and Gal-3 changed in their content and localization when neutrophils adhere to endothelia, suggesting a process of sensitive-balance between two endogenous anti- and pro-inflammatory mediators. (c) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

Alchornea glandulosa Ethyl Acetate Fraction Exhibits Antiangiogenic Activity: Preliminary Findings from In Vitro Assays Using Human Umbilical Vein Endothelial Cells

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fibrinogen-Induced Streptococcus mutans Biofilm Formation and Adherence to Endothelial Cells

Streptococcus mutans, the predominant bacterial species associated with dental caries, can enter the bloodstream and cause infective endocarditis. The aim of this study was to investigate S. mutans biofilm formation and adherence to endothelial cells induced by human fibrinogen. The putative mechanism by which biofilm formation is induced as well as the impact of fibrinogen on S. mutans resistance to penicillin was also evaluated. Bovine plasma dose dependently induced biofilm formation by S. mutans. Of the various plasma proteins tested, only fibrinogen promoted the formation of biofilm in a dose-dependent manner. Scanning electron microscopy observations revealed the presence of complex aggregates of bacterial cells firmly attached to the polystyrene support. S. mutans in biofilms induced by the presence of fibrinogen was markedly resistant to the bactericidal effect of penicillin. Fibrinogen also significantly increased the adherence of S. mutans to endothelial cells. Neither S. mutans cells nor culture supernatants converted fibrinogen into fibrin. However, fibrinogen is specifically bound to the cell surface of S. mutans and may act as a bridging molecule to mediate biofilm formation. In conclusion, our study identified a new mechanism promoting S. mutans biofilm formation and adherence to endothelial cells which may contribute to infective endocarditis.

Inflammatory response of endothelial cells to hepatitis C virus recombinant envelope glycoprotein 2 protein exposure

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)