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Role of polyphenols in improving endothelial dysfunction in diabetes
C.G. Fraga, P. Oteiza / Free Radical Biology and Medicine 75 (2014) S3–S12
The modulation of the HDL receptor scavenger receptor B1 (SRB1) was evaluated in skin fibroblasts isolated from Rett syndrome (RTT) patients, a rare neurodevelopmental disorder affecting almost exclusively females associated in up to 95% of cases to de novo loss-of-function mutations in the Xchromosome-linked gene encoding the methyl-CpG-binding protein 2 (MeCP2). Patients showed an altered plasma lipid profile, while their skin fibroblasts showed a dramatic reduction in SRB1 (immunogold, Western blot and immunohistochemistry). The decreased SRB1 levels were demonstrated to be the consequence of its binding with 4-hydroxy-2-nonenal (4HNE), a product of lipid peroxidation, and its increased ubiquitination. Therefore the loss of SRB1 in RTT cells is a consequence of the chronic oxidative stress status present in RTT. In addition RTT fibroblast presented high intracellular levels of H2O2 and 4HNE protein adducts. This finding was correlated with the constitutive activation of NADPH oxidase (NOX) and was reverted by DPI (NOX inhibitor) or Desferal (Iron chelator) pre-treatment. To confirm the alteration of status redox in RTT cells, the activity of several enzymes involved in protecting the cell from OS was also evaluated. Glutathione peroxidase (GPx), Supeoxide dismutase and Glucose-6-phosphate dehydrogenase (G6PDH) activity were decreased respect to control. These data paralleled with a constitutive activation of NRF2 and elevated gene expression of Heme oxigenase-1 (HO-1) and NAD(P)H dehydrogenase quinone 1 (NQO-1). Of note, when NRF2 pathway was stimulated via exogenous oxidants, RTT fibroblast did not respond as the control cells.
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.855
Symposium 8: Cardiovascular nutrigenomics: Perspectives for ageing, healthspan and beyond
S11
S8-2
Nutrigenomic programming of cardiovascular and metabolic diseases Susan Ozanne University of Cambridge (Institute of Metabolic Science), Clinical Biochemistry, UK Over twenty five years ago epidemiological studies revealed that there was a relationship between patterns of early growth and subsequent risk of diseases such as type 2 diabetes, cardiovascular disease and the metabolic syndrome. Studies of identical twins, individuals who were in utero during periods of famine, discordant siblings and animal models have provided strong evidence that the early environment plays an important role in mediating these relationships. Early nutrition is one such important environmental factor. The concept of early life programming is therefore widely accepted and the underlying mechanisms starting to emerge. These include: (1) Permanent structural changes in an organ due to exposure to suboptimal levels of essential hormones or nutrients during a critical period of development leading to permanent changes in tissue function (2) Persistent epigenetic changes such as DNA methylation and histone modifications and miRNAs leading to changes in gene expression. (3) Permanent effects on regulation of cellular ageing through increases in oxidative stress and mitochondrial dysfunction leading to DNA damage and telomere shortening. Further understanding of these processes will enable the development of preventative and intervention strategies to combat the burden of common diseases such as type 2 diabetes and cardiovascular disease.
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.857
S8-1
MicroRNAs as novel cardiovascular health
nutrigenomic
targets
for S8-3
Dragan Milenkovic INRA, Centre de Clermont-Ferrand/Theix, Unité de Nutrition Humaine, Clermont-Ferrand, France Consumption of flavanol-rich foods is associated with a reduced risk of cardiovascular diseases, which was linked to improvements in endothelial function. The specific flavanols involved in these beneficial effects and underlying molecular mechanisms is still largely unknown. We have shown that exposure of TNFα-activated endothelial cells to flavanol metabolites (4’-Omethyl( )-epicatechin, 4’-O-methyl( )-epicatechin-7-β-D-glucuronide and ()epicatechin-4’-sulfate) at physiologically-relevant concentrations decreased the adhesion of monocytes to endothelial monolayers. Nutrigenomic analysis showed that these metabolites modulate expression of genes involved in the regulation of cell adhesion/junctions, focal adhesion or cytoskeleton remodeling, and this by affecting phosphorylation levels of p65 and p38 of NF-κB and MAPK cell-signaling pathways respectively. Together with cell signaling pathways, microRNAs (short, endogenous, noncoding, single-stranded RNAs) represent another class of molecular post-transcriptional regulators of gene expression. Our nutrigenomic studies have shown that exposure of endothelial cells to the same metabolites can also modulate the expression of miRNAs. Among differentially-expressed miRNAs are those involved in the regulation of inflammation or cell adhesion, such as miR-221 and miR-181. Bioinformatic analysis shows that the potential target genes these miRNAs are also involved in regulation of cell adhesion, cytoskeleton, focal adhesion, transendothelial migration. These miRNAs could exert post-transcriptional regulation by inhibiting protein synthesis, as BIRC2, or by inducing mRNA degradation, as WASP1. These data suggest that miRNAs are important molecular targets of flavanol metabolites involved in the regulation of expression of genes controlling adhesion and transendothelial migration processes. This original result contributes to increase the knowledge about the mechanisms underlying the protective effect of flavanols on vascular endothelium.
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.856
Role of polyphenols in dysfunction in diabetes
improving
endothelial
Valérie Schini-Kerth Faculté de Pharmacie, UMR CNRS 7213, Strasbourg University, Strasbourg, France
Endothelial cells covering the luminal surface of all blood vessels have a pivotal role in the control of vascular homeostasis mostly via the activation of protective mechanisms. These mechanisms include the endothelial formation of nitric oxide (NO) in response to the activation of endothelial NO synthase, endothelium-dependent hyperpolarization involving endothelial SKCa and IKCa, which is subsequently transmitted to the underlying vascular smooth muscle via myoendothelial junctions, and in some blood vessels, also prostacyclin. These endothelial protective mechanisms will promote vasodilatation, inhibit platelet activation, and also prevent the expression of pro-atherothrombotic factors. In most types of cardiovascular diseases including type 1 and 2 diabetes (T2D), an endothelial dysfunction as indicated by blunted endotheliumdependent vasorelaxations and often also by the appearance of endothelium-dependent cyclooxygenase-mediated contractile responses is observed early in the development of the pathology and has been suggested to contribute to the development of both macro-vascular and micro-vascular complications in T2D. The impaired endothelium-dependent relaxations in T2D has indicated the involvement of reduced NO and endotheliumdependent hyperpolarization components and is associated with increased oxidative stress in the arterial wall involving superoxide anion and hydrogen peroxide predominantly due to an up-regulation of NADPH oxidase and possibly also uncoupling of endothelial NO synthase. Investigations in experimental animals and humans have also suggested that the angiotensin system contributes to the impaired endothelial function in T2D.
S12
C.G. Fraga, P. Oteiza / Free Radical Biology and Medicine 75 (2014) S3–S12
Several sources of polyphenols (i.e., cocoa and plant extracts) have been shown to retard the induction of endothelial dysfunction in TD2 in part by preventing oxidative stress in the arterial wall most likely by normalizing the expression of NADPH oxidase, cyclooxygenase-1 and 2, eNOS uncoupling, and the angiotensin system. Both pre-clinical and clinical data will be presented and discussed. In addition, polyphenols may possibly also improve the endothelial function by preventing the induction of endothelial senescence to high glucose and angiotensin II. Thus, polyphenols by improving the endothelial dysfunction might help to retard the development of both macroand micro-vascular complications in diabetes.
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.858
S8-4
Flavanols and vascular health: molecular mechanisms to build evidence-based recommendations Cesar G. Fraga a, Patricia Oteiza b
Observational studies as well as public awareness and ancient medicine identify tea, wine and cocoa as healthy foods. Further compilations of epidemiological data reinforce the healthy properties of the grape, tea and cocoa derived foods and drinks made from, especially when considering cardiovascular disease, some cancers and other inflammation-related pathologies. Flavanols have emerged as bioactives responsible for such health effects, and flavanol-rich foods have been used in clinical studies. Results of these studies show a major participation of flavanols in mechanisms positively affecting endpoints of cardiovascular disease, i.e. hypertension and vascular function. In line, based on the chemistry (bioavailability and molecular structure of flavanol and target entities) several physiological mechanisms have been described backing the epidemiological and clinical studies. In summary, the discussion for defining evidence-based recommendations for flavanols is based on: a) the extensive research done and the positive results obtained support the incorporation of flavanol-rich foods as part of a healthy diet, this is a cost-effective action to ameliorate silent undesirable conditions as it is chronic inflammation; b) the fact that cardiovascular health seems especially sensitive to the beneficial effects of flavanols: based on clinical and mechanistic studies showing that certain flavanols, favor NO production; and c) the increasing technical possibilities to evaluate flavanols in foods and biological samples. Supported by UBACyT 20020120100177, CONICET PIP20110100752, and ANPCyT PICT 2012/0765. & 2014 Published by Elsevier Inc.
a
University of Buenos Aires (School of Pharmacy and Biochemistry), Physical Chemistry-IBIMOL, Argentina b University of California (Davis), Department of Nutrition and Department of Environmental Toxicology, USA
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.859
The modulation of the HDL receptor scavenger receptor B1 (SRB1) was evaluated in skin fibroblasts isolated from Rett syndrome (RTT) patients, a rare neurodevelopmental disorder affecting almost exclusively females associated in up to 95% of cases to de novo loss-of-function mutations in the Xchromosome-linked gene encoding the methyl-CpG-binding protein 2 (MeCP2). Patients showed an altered plasma lipid profile, while their skin fibroblasts showed a dramatic reduction in SRB1 (immunogold, Western blot and immunohistochemistry). The decreased SRB1 levels were demonstrated to be the consequence of its binding with 4-hydroxy-2-nonenal (4HNE), a product of lipid peroxidation, and its increased ubiquitination. Therefore the loss of SRB1 in RTT cells is a consequence of the chronic oxidative stress status present in RTT. In addition RTT fibroblast presented high intracellular levels of H2O2 and 4HNE protein adducts. This finding was correlated with the constitutive activation of NADPH oxidase (NOX) and was reverted by DPI (NOX inhibitor) or Desferal (Iron chelator) pre-treatment. To confirm the alteration of status redox in RTT cells, the activity of several enzymes involved in protecting the cell from OS was also evaluated. Glutathione peroxidase (GPx), Supeoxide dismutase and Glucose-6-phosphate dehydrogenase (G6PDH) activity were decreased respect to control. These data paralleled with a constitutive activation of NRF2 and elevated gene expression of Heme oxigenase-1 (HO-1) and NAD(P)H dehydrogenase quinone 1 (NQO-1). Of note, when NRF2 pathway was stimulated via exogenous oxidants, RTT fibroblast did not respond as the control cells.
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.855
Symposium 8: Cardiovascular nutrigenomics: Perspectives for ageing, healthspan and beyond
S11
S8-2
Nutrigenomic programming of cardiovascular and metabolic diseases Susan Ozanne University of Cambridge (Institute of Metabolic Science), Clinical Biochemistry, UK Over twenty five years ago epidemiological studies revealed that there was a relationship between patterns of early growth and subsequent risk of diseases such as type 2 diabetes, cardiovascular disease and the metabolic syndrome. Studies of identical twins, individuals who were in utero during periods of famine, discordant siblings and animal models have provided strong evidence that the early environment plays an important role in mediating these relationships. Early nutrition is one such important environmental factor. The concept of early life programming is therefore widely accepted and the underlying mechanisms starting to emerge. These include: (1) Permanent structural changes in an organ due to exposure to suboptimal levels of essential hormones or nutrients during a critical period of development leading to permanent changes in tissue function (2) Persistent epigenetic changes such as DNA methylation and histone modifications and miRNAs leading to changes in gene expression. (3) Permanent effects on regulation of cellular ageing through increases in oxidative stress and mitochondrial dysfunction leading to DNA damage and telomere shortening. Further understanding of these processes will enable the development of preventative and intervention strategies to combat the burden of common diseases such as type 2 diabetes and cardiovascular disease.
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.857
S8-1
MicroRNAs as novel cardiovascular health
nutrigenomic
targets
for S8-3
Dragan Milenkovic INRA, Centre de Clermont-Ferrand/Theix, Unité de Nutrition Humaine, Clermont-Ferrand, France Consumption of flavanol-rich foods is associated with a reduced risk of cardiovascular diseases, which was linked to improvements in endothelial function. The specific flavanols involved in these beneficial effects and underlying molecular mechanisms is still largely unknown. We have shown that exposure of TNFα-activated endothelial cells to flavanol metabolites (4’-Omethyl( )-epicatechin, 4’-O-methyl( )-epicatechin-7-β-D-glucuronide and ()epicatechin-4’-sulfate) at physiologically-relevant concentrations decreased the adhesion of monocytes to endothelial monolayers. Nutrigenomic analysis showed that these metabolites modulate expression of genes involved in the regulation of cell adhesion/junctions, focal adhesion or cytoskeleton remodeling, and this by affecting phosphorylation levels of p65 and p38 of NF-κB and MAPK cell-signaling pathways respectively. Together with cell signaling pathways, microRNAs (short, endogenous, noncoding, single-stranded RNAs) represent another class of molecular post-transcriptional regulators of gene expression. Our nutrigenomic studies have shown that exposure of endothelial cells to the same metabolites can also modulate the expression of miRNAs. Among differentially-expressed miRNAs are those involved in the regulation of inflammation or cell adhesion, such as miR-221 and miR-181. Bioinformatic analysis shows that the potential target genes these miRNAs are also involved in regulation of cell adhesion, cytoskeleton, focal adhesion, transendothelial migration. These miRNAs could exert post-transcriptional regulation by inhibiting protein synthesis, as BIRC2, or by inducing mRNA degradation, as WASP1. These data suggest that miRNAs are important molecular targets of flavanol metabolites involved in the regulation of expression of genes controlling adhesion and transendothelial migration processes. This original result contributes to increase the knowledge about the mechanisms underlying the protective effect of flavanols on vascular endothelium.
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.856
Role of polyphenols in dysfunction in diabetes
improving
endothelial
Valérie Schini-Kerth Faculté de Pharmacie, UMR CNRS 7213, Strasbourg University, Strasbourg, France
Endothelial cells covering the luminal surface of all blood vessels have a pivotal role in the control of vascular homeostasis mostly via the activation of protective mechanisms. These mechanisms include the endothelial formation of nitric oxide (NO) in response to the activation of endothelial NO synthase, endothelium-dependent hyperpolarization involving endothelial SKCa and IKCa, which is subsequently transmitted to the underlying vascular smooth muscle via myoendothelial junctions, and in some blood vessels, also prostacyclin. These endothelial protective mechanisms will promote vasodilatation, inhibit platelet activation, and also prevent the expression of pro-atherothrombotic factors. In most types of cardiovascular diseases including type 1 and 2 diabetes (T2D), an endothelial dysfunction as indicated by blunted endotheliumdependent vasorelaxations and often also by the appearance of endothelium-dependent cyclooxygenase-mediated contractile responses is observed early in the development of the pathology and has been suggested to contribute to the development of both macro-vascular and micro-vascular complications in T2D. The impaired endothelium-dependent relaxations in T2D has indicated the involvement of reduced NO and endotheliumdependent hyperpolarization components and is associated with increased oxidative stress in the arterial wall involving superoxide anion and hydrogen peroxide predominantly due to an up-regulation of NADPH oxidase and possibly also uncoupling of endothelial NO synthase. Investigations in experimental animals and humans have also suggested that the angiotensin system contributes to the impaired endothelial function in T2D.
S12
C.G. Fraga, P. Oteiza / Free Radical Biology and Medicine 75 (2014) S3–S12
Several sources of polyphenols (i.e., cocoa and plant extracts) have been shown to retard the induction of endothelial dysfunction in TD2 in part by preventing oxidative stress in the arterial wall most likely by normalizing the expression of NADPH oxidase, cyclooxygenase-1 and 2, eNOS uncoupling, and the angiotensin system. Both pre-clinical and clinical data will be presented and discussed. In addition, polyphenols may possibly also improve the endothelial function by preventing the induction of endothelial senescence to high glucose and angiotensin II. Thus, polyphenols by improving the endothelial dysfunction might help to retard the development of both macroand micro-vascular complications in diabetes.
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.858
S8-4
Flavanols and vascular health: molecular mechanisms to build evidence-based recommendations Cesar G. Fraga a, Patricia Oteiza b
Observational studies as well as public awareness and ancient medicine identify tea, wine and cocoa as healthy foods. Further compilations of epidemiological data reinforce the healthy properties of the grape, tea and cocoa derived foods and drinks made from, especially when considering cardiovascular disease, some cancers and other inflammation-related pathologies. Flavanols have emerged as bioactives responsible for such health effects, and flavanol-rich foods have been used in clinical studies. Results of these studies show a major participation of flavanols in mechanisms positively affecting endpoints of cardiovascular disease, i.e. hypertension and vascular function. In line, based on the chemistry (bioavailability and molecular structure of flavanol and target entities) several physiological mechanisms have been described backing the epidemiological and clinical studies. In summary, the discussion for defining evidence-based recommendations for flavanols is based on: a) the extensive research done and the positive results obtained support the incorporation of flavanol-rich foods as part of a healthy diet, this is a cost-effective action to ameliorate silent undesirable conditions as it is chronic inflammation; b) the fact that cardiovascular health seems especially sensitive to the beneficial effects of flavanols: based on clinical and mechanistic studies showing that certain flavanols, favor NO production; and c) the increasing technical possibilities to evaluate flavanols in foods and biological samples. Supported by UBACyT 20020120100177, CONICET PIP20110100752, and ANPCyT PICT 2012/0765. & 2014 Published by Elsevier Inc.
a
University of Buenos Aires (School of Pharmacy and Biochemistry), Physical Chemistry-IBIMOL, Argentina b University of California (Davis), Department of Nutrition and Department of Environmental Toxicology, USA
http://dx.doi.org/10.1016/j.freeradbiomed.2014.10.859