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0274 : Exosomes from metabolic syndrome patients induce endothelial dysfunction through mitochondrial-generated oxidative stress
216
Archives of Cardiovascular Diseases Supplements (2016) 8, 216-218
Topic 10 – Oxidative Stress, NO April 07th, Thursday 2016
0274 Exosomes from metabolic syndrome patients induce endothelial dysfunction through mitochondrial-generated oxidative stress Marine Malloci * (1), Séverine Dubois (2), Ramaroson Andriantsitohaina (1), Gilles Simard (1), Carmen Martinez (1) (1) Université d’Angers – IBS, CHU Angers, INSERM U1063, Angers, France – (2) CHU Angers, Angers, France * Corresponding author: [email protected] (Marine Malloci) Metabolic syndrome (MetS) is characterized by a cluster of interrelated risk factors -hyperglycemia, dyslipidemia, hypertension and obesity-leading to an increased risk of cardiovascular events. Exosomes are nanoscaled vesicles (30100 nm) released by cells, that bear proteins and nucleic acids. It has been demonstrated that circulating exosome rate is positively correlated with (i) an increase of inflammation, (ii) a decrease of HDL cholesterol and (iii) prevalence of MetS. However, it is unknown whether exosomes from MetS patients can act as biological vectors through their interaction with target cells.We hypothesized that exosomes may be implicated in MetS-associated endothelial dysfunction. Circulating exosomes from healthy subjects and MetS patients have been isolated from plasma and, then, characterized. As expected, isolated exosomes have an average size of 63±15 nm and are enriched in exosomal specific proteins, tetraspanins such as CD81, CD9, CD63 and endolysosomal protein TSG101. Moreover, the majority of plasmatic exosomes are from leukocyte and platelet origins in both healthy subjects and MetS patients. MetS patients display increased levels of exosomes compared to healthy subjects. We demonstrated that treatment of human endothelial aortic cells with exosomes from MetS patients induce endothelial dysfunction associated with decreased nitric oxide and increased reactive oxygen species (ROS) production. The increase on fluorescence associated to Mitosox suggests an enhanced production of mitochondrial ROS following 4 hours of MetS exosome treatment. These data provide evidence that circulating exosomes from MetS patients induce endothelial dysfunction via both increased oxidative stress and reduced nitric oxide production. Altogether, we show exosomes as novel players implicated in endothelial dysfunction associated with MetS and consequently potential targets to prevent and treat vascular consequences of this syndrome. The author hereby declares no conflict of interest
0343 Importance of the membrane estrogen receptor alpha (ER ) in the vascular response to shear stress in mice Julie Favre * (1), Emilie Vessière (1), Anne-Laure Guihot (1), Linda Grimaud (1), Laurent Loufrani (1), Jean-François Arnal (2), Françoise Lenfant (2), Daniel Henrion (1) (1) Faculté de Médecine, CNRS UMR6214, INSERM UMR1083, Angers, France – (2) CHU Toulouse, Rangueil, INSERM/UPS UMR 1048, Toulouse, France * Corresponding author: [email protected] (Julie Favre) Resistance arteries are sensitive to mechanical forces exerted on the vessel wall. While endothelial shear stress triggers flow-mediated dilation (FMD), chronic increase in shear forces drives expansive arterial remodeling. We showed previously that endothelial estrogen receptor alpha (ERα) controlled this adaptive remodeling. We aimed to evaluate ERα contribution in acute response to flow, by using various genetic models of ERα deficiency in male mice, reducing estrogen hormonal influence. FMD was evaluated following step increase in flow applied to pressurized mesenteric arteries (arteriography). Arteries were isolated from wild-type (WT), (i) ERαKO, or mice invalidated for (ii) the ligand-dependent transactivation function AF2 of ERa (AF2°) and (iii) the plasma membrane-located ERα (mutated for the palmitoylation site C451A). In mice deficient in ERα, FMD was attenuated (dilation 50μl/min
© Elsevier Masson SAS. All rights reserved.
WT: 59+/–4% vs. ERαKO: 41+/–4% p<0.01) without significant modification in response to acetylcholine. Invalidation of AF2 (ERα nuclear transcriptional action) only partially impacted FMD (WT: 61+/–5% vs. AF2°: 51+/–5%). Ex vivo ligand-dependent activation of ERα with 17β estradiol or blockade by ICI 182,780 had no significant effect on FMD in WT arteries. Importantly, invalidation of membrane ERα (C451A) markedly altered FMD (WT: 56+/–7% vs. C451A: 34+/–6% p<0.05). In contrast to ERαKO and AF2°, C451A arteries showed a reduced dilating response to acetylcholine but only a decreased sensitivity to insulin, which shares common intracellular pathways triggered by shear stress, without altering maximal vasodilation (WT: 31+/–7% vs. C451A: 15+/–3% p<0.05). We show for the first time that membrane ERα contributes to arterial shear-sensing irrespective of the presence of its agonist. Cell membrane ERα participates to vascular homeostasis and could constitute a novel therapeutical target in peripheral vascular diseases. The author hereby declares no conflict of interest
0169 Effects of intermittent hypoxia on rat ophthalmic artery reactivity: role of endothelin 1, oxidative stress and endothelium derived hyperpolarizing factors Marielle Mentek *, Marie Baldazza, Jessica Morand, Gilles Faury, Florent Aptel, Diane Godin-Ribuot, Christophe Chiquet Université de Grenoble, INSERM U1042, Grenoble, France * Corresponding author: [email protected] (Marielle Mentek) Obstructive sleep apnea (OSA) is a common disease, characterized by recurrent desaturation-reoxygenation sequences. Intermittent hypoxia (IH) has been proposed as major component of OSA. OSA has been recently associated with a higher frequency of optic neuropathies. There are currently no pathophysiological data regarding the effect of HI or OSA on ocular vascular system. This study aims to characterize IH impact on rat ophthalmic artery (OA) reactivity. Particularly, the role of endothelin 1 (ET-1), oxidative stress and endothelium derived hyperpolarizing factors (EDHF) were studied. Rats were exposed to 14 days IH (IH rats) or normoxia (NX rats). Ophthalmic artery reactivity was studied using wire myography. Endothelin A receptor (ETRA) expression and superoxide anions production in OA were studied by immunohistolabelling and DHE labelling respectively. After 14 days IH, ETRA immunolabeling and superoxide anions expression in OA were increased by 22 % (p = 0.015) and 23 % (p = 0.04) respectively in IH rats. Ophthalmic artery contraction to 3.10-8 M ET-1 was increased by 16% (p<0.05) in IH rats. ETRA blockage (BQ-123) almost completely abolished contractile response to ET-1 in both groups. Endothelin B receptor (ETRB) blockage (BQ-788) increased response to ET-1 in NX rats but not in IH rats. Relaxation to acetylcholine (Ach) was significantly delayed in IH rats (p<0.0001). After NOS blockade with L-NAME, difference in Ach induced relaxation between groups was abolished. Cytochrome P450 inhibition by fluconazole had an opposite effect on response to Ach in NX and IH rats, increasing relaxation to Ach in IH rats and delaying it in NX rats. 14-day IH-exposure induces endothelial dysfunction in rat ophtalmic artery, associated with increase in oxidative stress and change in EDHF contribution to endothelial function. The increased contractile response to ET-1 in IH rats was due to an increase in ETRA -vasoconstriction and a decrease in ETRB vasorelaxation. The author hereby declares no conflict of interest
0134 Atrial fibrillation is associated with a marker of endothelial function and oxidative stress in patients with acute myocardial infarction Karim Stamboul (1), Julie Lorin (2), Luc Lorgis (1), Jean-Claude Beer (1), Claude Touzery (1), Luc Rochette (2), Catherine Vergely (2), Yves Cottin (1), Marianne Zeller * (2) (1) CHU Dijon, Bocage, Dijon, France – (2) Université de Bourgogne, INSERM U866, Dijon, France * Corresponding author: [email protected] (Marianne Zeller) Background Atrial fibrillation (AF), whether silent or symptomatic, is a frequent and severe complication of acute myocardial infarction (AMI). Asymmetric dimethylarginine (ADMA), an endogenous eNOS inhibitor, is a
Archives of Cardiovascular Diseases Supplements (2016) 8, 216-218
Topic 10 – Oxidative Stress, NO April 07th, Thursday 2016
0274 Exosomes from metabolic syndrome patients induce endothelial dysfunction through mitochondrial-generated oxidative stress Marine Malloci * (1), Séverine Dubois (2), Ramaroson Andriantsitohaina (1), Gilles Simard (1), Carmen Martinez (1) (1) Université d’Angers – IBS, CHU Angers, INSERM U1063, Angers, France – (2) CHU Angers, Angers, France * Corresponding author: [email protected] (Marine Malloci) Metabolic syndrome (MetS) is characterized by a cluster of interrelated risk factors -hyperglycemia, dyslipidemia, hypertension and obesity-leading to an increased risk of cardiovascular events. Exosomes are nanoscaled vesicles (30100 nm) released by cells, that bear proteins and nucleic acids. It has been demonstrated that circulating exosome rate is positively correlated with (i) an increase of inflammation, (ii) a decrease of HDL cholesterol and (iii) prevalence of MetS. However, it is unknown whether exosomes from MetS patients can act as biological vectors through their interaction with target cells.We hypothesized that exosomes may be implicated in MetS-associated endothelial dysfunction. Circulating exosomes from healthy subjects and MetS patients have been isolated from plasma and, then, characterized. As expected, isolated exosomes have an average size of 63±15 nm and are enriched in exosomal specific proteins, tetraspanins such as CD81, CD9, CD63 and endolysosomal protein TSG101. Moreover, the majority of plasmatic exosomes are from leukocyte and platelet origins in both healthy subjects and MetS patients. MetS patients display increased levels of exosomes compared to healthy subjects. We demonstrated that treatment of human endothelial aortic cells with exosomes from MetS patients induce endothelial dysfunction associated with decreased nitric oxide and increased reactive oxygen species (ROS) production. The increase on fluorescence associated to Mitosox suggests an enhanced production of mitochondrial ROS following 4 hours of MetS exosome treatment. These data provide evidence that circulating exosomes from MetS patients induce endothelial dysfunction via both increased oxidative stress and reduced nitric oxide production. Altogether, we show exosomes as novel players implicated in endothelial dysfunction associated with MetS and consequently potential targets to prevent and treat vascular consequences of this syndrome. The author hereby declares no conflict of interest
0343 Importance of the membrane estrogen receptor alpha (ER ) in the vascular response to shear stress in mice Julie Favre * (1), Emilie Vessière (1), Anne-Laure Guihot (1), Linda Grimaud (1), Laurent Loufrani (1), Jean-François Arnal (2), Françoise Lenfant (2), Daniel Henrion (1) (1) Faculté de Médecine, CNRS UMR6214, INSERM UMR1083, Angers, France – (2) CHU Toulouse, Rangueil, INSERM/UPS UMR 1048, Toulouse, France * Corresponding author: [email protected] (Julie Favre) Resistance arteries are sensitive to mechanical forces exerted on the vessel wall. While endothelial shear stress triggers flow-mediated dilation (FMD), chronic increase in shear forces drives expansive arterial remodeling. We showed previously that endothelial estrogen receptor alpha (ERα) controlled this adaptive remodeling. We aimed to evaluate ERα contribution in acute response to flow, by using various genetic models of ERα deficiency in male mice, reducing estrogen hormonal influence. FMD was evaluated following step increase in flow applied to pressurized mesenteric arteries (arteriography). Arteries were isolated from wild-type (WT), (i) ERαKO, or mice invalidated for (ii) the ligand-dependent transactivation function AF2 of ERa (AF2°) and (iii) the plasma membrane-located ERα (mutated for the palmitoylation site C451A). In mice deficient in ERα, FMD was attenuated (dilation 50μl/min
© Elsevier Masson SAS. All rights reserved.
WT: 59+/–4% vs. ERαKO: 41+/–4% p<0.01) without significant modification in response to acetylcholine. Invalidation of AF2 (ERα nuclear transcriptional action) only partially impacted FMD (WT: 61+/–5% vs. AF2°: 51+/–5%). Ex vivo ligand-dependent activation of ERα with 17β estradiol or blockade by ICI 182,780 had no significant effect on FMD in WT arteries. Importantly, invalidation of membrane ERα (C451A) markedly altered FMD (WT: 56+/–7% vs. C451A: 34+/–6% p<0.05). In contrast to ERαKO and AF2°, C451A arteries showed a reduced dilating response to acetylcholine but only a decreased sensitivity to insulin, which shares common intracellular pathways triggered by shear stress, without altering maximal vasodilation (WT: 31+/–7% vs. C451A: 15+/–3% p<0.05). We show for the first time that membrane ERα contributes to arterial shear-sensing irrespective of the presence of its agonist. Cell membrane ERα participates to vascular homeostasis and could constitute a novel therapeutical target in peripheral vascular diseases. The author hereby declares no conflict of interest
0169 Effects of intermittent hypoxia on rat ophthalmic artery reactivity: role of endothelin 1, oxidative stress and endothelium derived hyperpolarizing factors Marielle Mentek *, Marie Baldazza, Jessica Morand, Gilles Faury, Florent Aptel, Diane Godin-Ribuot, Christophe Chiquet Université de Grenoble, INSERM U1042, Grenoble, France * Corresponding author: [email protected] (Marielle Mentek) Obstructive sleep apnea (OSA) is a common disease, characterized by recurrent desaturation-reoxygenation sequences. Intermittent hypoxia (IH) has been proposed as major component of OSA. OSA has been recently associated with a higher frequency of optic neuropathies. There are currently no pathophysiological data regarding the effect of HI or OSA on ocular vascular system. This study aims to characterize IH impact on rat ophthalmic artery (OA) reactivity. Particularly, the role of endothelin 1 (ET-1), oxidative stress and endothelium derived hyperpolarizing factors (EDHF) were studied. Rats were exposed to 14 days IH (IH rats) or normoxia (NX rats). Ophthalmic artery reactivity was studied using wire myography. Endothelin A receptor (ETRA) expression and superoxide anions production in OA were studied by immunohistolabelling and DHE labelling respectively. After 14 days IH, ETRA immunolabeling and superoxide anions expression in OA were increased by 22 % (p = 0.015) and 23 % (p = 0.04) respectively in IH rats. Ophthalmic artery contraction to 3.10-8 M ET-1 was increased by 16% (p<0.05) in IH rats. ETRA blockage (BQ-123) almost completely abolished contractile response to ET-1 in both groups. Endothelin B receptor (ETRB) blockage (BQ-788) increased response to ET-1 in NX rats but not in IH rats. Relaxation to acetylcholine (Ach) was significantly delayed in IH rats (p<0.0001). After NOS blockade with L-NAME, difference in Ach induced relaxation between groups was abolished. Cytochrome P450 inhibition by fluconazole had an opposite effect on response to Ach in NX and IH rats, increasing relaxation to Ach in IH rats and delaying it in NX rats. 14-day IH-exposure induces endothelial dysfunction in rat ophtalmic artery, associated with increase in oxidative stress and change in EDHF contribution to endothelial function. The increased contractile response to ET-1 in IH rats was due to an increase in ETRA -vasoconstriction and a decrease in ETRB vasorelaxation. The author hereby declares no conflict of interest
0134 Atrial fibrillation is associated with a marker of endothelial function and oxidative stress in patients with acute myocardial infarction Karim Stamboul (1), Julie Lorin (2), Luc Lorgis (1), Jean-Claude Beer (1), Claude Touzery (1), Luc Rochette (2), Catherine Vergely (2), Yves Cottin (1), Marianne Zeller * (2) (1) CHU Dijon, Bocage, Dijon, France – (2) Université de Bourgogne, INSERM U866, Dijon, France * Corresponding author: [email protected] (Marianne Zeller) Background Atrial fibrillation (AF), whether silent or symptomatic, is a frequent and severe complication of acute myocardial infarction (AMI). Asymmetric dimethylarginine (ADMA), an endogenous eNOS inhibitor, is a