Update on the Role of Cannabinoid Receptors after Ischemic Stroke

Cannabinoids are considered as key mediators in the pathophysiology of inflammatory diseases, including atherosclerosis. In particular, they have been shown to reduce the ischemic injury after acute cardiovascular events, such as acute myocardial infarction and ischemic stroke. These protective and anti-inflammatory properties on peripheral tissues and circulating inflammatory have been demonstrated to involve their binding with both selective cannabinoid type 1 (CB1) and type 2 (CB2) transmembrane receptors. On the other hands, the recent discoveries of novel different classes of cannabinoids and receptors have increased the complexity of this system in atherosclerosis. Although only preliminary data have been reported on the activities of novel cannabinoid receptors, several studies have already investigated the role of CB1 and CB2 receptors in ischemic stroke. While CB1 receptor activation has been shown to directly reduce atherosclerotic plaque inflammation, controversial data have been shown on neurotransmission and neuroprotection after stroke. Given its potent anti-inflammatory activities on circulating leukocytes, the CB2 activation has been proven to produce protective effects against acute poststroke inflammation. In this paper, we will update evidence on different cannabinoid-triggered avenues to reduce inflammation and neuronal injury in acute ischemic stroke

L-NAME treatment enhances exercise-induced content of myocardial heat shock protein 72 (Hsp72) in rats

Background/Aim: Nitric oxide (NO) modulates the expression of the chaperone Hsp72 in the heart, and exercise stimulates both NO production and myocardial Hsp72 expression. The main purpose of the study was to investigate whether NO interferes with an exercise-induced myocardial Hsp72 expression. Methods: Male Wistar rats (70-100 days) were divided into control (C, n= 12), L-NAME-treated (L, n= 12), exercise (E, n= 13) and exercise plus L-NAME-treated (EL, n= 20) groups. L-NAME was given in drinking water (700 mg. L-1) and the exercise was performed on a treadmill (15-25 m.min(-1), 40-60 min. day(-1)) for seven days. Left ventricle (LV) protein Hsp content, NOS and phosphorylated-NOS (p-NOS) isoforms were measured using Western blotting. The activity of NOS was assayed in LV homogenates by the conversion of [H-3] L-arginine to [H-3] L-citrulline. Results: Hsp72 content was increased significantly (223%; p < 0.05) in the E group compared to the C group, but exercise alone did not alter the NOS content, p-NOS isoforms or NOS activity. Contrary to our expectation, L-NAME enhanced (p < 0.05) the exercise-induced Hsp72 content (EL vs. C, L and E groups = 1019%, 548% and 457%, respectively). Although the EL group had increased stimulatory p-eNOS(Ser1177) (over 200%) and decreased inhibitory p-nNOS(Ser852) (similar to 50%) compared to both the E and L groups (p < 0.05), NOS activity was similar in all groups. Conclusions: Our results suggest that exercise-induced cardiac Hsp72 expression does not depend on NO. Conversely, the in vivo L-NAME treatment enhances exercise-induced Hsp72 production. This effect may be due to an increase in cardiac stress. Copyright (C) 2011 S. Karger AG, Basel275479486CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA E INOVAÇÃO DO ESPÍRITO SANTO - FAPESsem informaçã

Role of renin-angiotensin system in inflammation, immunity and aging

Recent data support the idea that the effects of RAS are not restricted to the cardiovascular and renal systems. Importantly, RAS modulates free radical production and the cellular synthesis of several molecules such as cytokines, chemokines and transcription factors. These functions reflect directly the RAS ability to modulate the cell growth, senescence and migration. Activation of the classic RAS, ACE/Ang II/AT1R, has been strictly related to down regulation of pro-survival genes (Nampt and Sirt3), increase in ROS production and pro-inflammatory cytokines and chemokines release, leading to cell senescence, inflammation and development of autoimmune dysfunctions. However, the new view of RAS, points to the ACE2/Ang-(1-7)/Mas receptor axis as a counter-regulator of the effects of the classic Ang II-mediated effects. This new pathway is not totally elucidated. However, some studies suggest an important role of this novel axis in the control of cytokines release as well as cell migration and synthesis, preventing extra-cellular matrix deposition and cell apoptosis. Classic RAS blockers have been proposed as anti-inflammatory and immunomodulatory agents and some studies suggest a new potential application of RAS blockers in autoimmune diseases. The aim of the present review is to update the novel roles of classical and new RAS components and their possible implication during the physiological aging, in the immune system and inflammation

Role of ERK1/2 activation and nNOS uncoupling on endothelial dysfunction induced by lysophosphatidylcholine

Background and aims: Lysophosphatidylcholine (LPC) - a main component of oxidized LDL -is involved in endothelial dysfunction that precedes atherosclerosis, with an increased superoxide anions and a reduced NO production via endothelial NO synthase (eNOS) uncoupling. However, there is no evidence about the mechanisms involved in neuronal NOS (nNOS) uncoupling. Extracellular signal-regulated kinase (ERK) is related to the control of NO production and inflammatory gene transcription activation in atherosclerosis. Our aim was to investigate the role of nNOS/ERK1/2 pathway on endothelial dysfunction induced by LPC, in mouse aorta and human endothelial cells. Methods: Thoracic aorta from wild type mice was used to perform vascular reactivity studies in the presence or absence of LPC. Human endothelial cells were used to investigate the effect of LPC on expression of nNOS and his products NO and H2O2. Results: LPC reduced acetylcholine (ACh)-induced vasodilation in mouse aorta (Emax(CT/LPC) = similar to 95 +/- 2/ 62 +/- 3%, p = 0.0004) and increased phenylephrine-induced vasoconstriction (Emax(CT/LPC) = similar to 4 +/- 0,1/ 6 +/- 0,1 mN/mm, p = 0.0002), with a reduction in NO (fluorescence intensity(CT/LPC) = 91 +/- 3/62 +/- 2 x 10(3), p = 0.0002) and H2O2 (fluorescence intensityCT/LPC = similar to 16 +/- 0,8/10 +/- 0,7 x 10(3), p = 0.0041) production evocated by ACh. An inhibition of nNOS by TRIM (Emax(CT/CT+TRIM) = similar to 93 +/- 1/43 +/- 3%, p = 0,0048; Emax(LPC/LPC+TRIM) = similar to 62 +/- 3/65 +/- 3%) or H2O2 degradation by catalase (Emax(CT/CT+cat) = similar to 93 +/- 1/46 +/- 2%, p < 0,001; Emax(LPC/LPC+cat) = similar to 62,8 +/- 3,2/60,5 +/- 4,7%) reduced the relaxation in the control but not in LPC group. PD98059, an ERK1/2 inhibitor, abolished the increase in vasoconstriction in LPC-treated vessels (Emax(LPC/LPC+PD) = similar to 6 +/- 0,1/3 +/- 0,1 mN/mm, p = 0.0001). LPC also reduced the dimer/monomer proportion and increased nNOS(ser852) phosphorylation. Conclusions: LPC induced nNOS uncoupling and nNOS(Ser852) phosphorylation, reduced NO and H2O2 production and improved superoxide production by modulating ERK1/2 activity in human and murine endothelial cells. (C) 2016 Elsevier Ireland Ltd. All rights reserved

Paraquat poisoning induces TNF-α-dependent iNOS/NO mediated hyporesponsiveness of the aorta to vasoconstrictors in rats.

Paraquat is a toxic herbicide that may induce acute lung injury, circulatory failure and death. The present work aimed at investigating whether there is systemic inflammation and vascular dysfunction after paraquat exposure and whether these parameters were related. There was neutrophilia and accumulation of neutrophils in lung and bronchoalveolar lavage of animals given paraquat. This was associated with an increase in serum levels of TNF-α. In rats given paraquat, the relaxant response of aortic rings to acetylcholine was not modified but the contractile response to phenylephrine was greatly reduced. Endothelium removal or treatment with non-selective (L-NAME) or selective (L-NIL) inhibitors of inducible nitric oxide synthase (iNOS) restored contraction of aortas. There was greater production of nitric oxide (NO), which was restored to basal level by L-NIL, and greater expression of iNOS in endothelial cells, as seen by Western blot analyses and confocal microscopy. Blockade of TNF-α reduced pulmonary and systemic inflammation and vascular dysfunction. Together, our results clearly show that paraquat causes pulmonary and systemic inflammation, and vascular dysfunction in rats. Vascular dysfunction is TNF-α dependent, associated with enhanced expression of iNOS in aortic endothelial cells and greater NO production, which accounts for the decreased responsiveness of aortas to vasoconstrictors. Blockers of TNF-α may be useful in patients with paraquat poisoning

Vascular Kinin B1 and B2 Receptors Determine Endothelial Dysfunction through Neuronal Nitric Oxide Synthase

B1- and B2-kinin receptors are G protein-coupled receptors that play an important role in the vascular function. Therefore, the present study was designed to evaluate the participation of kinin receptors in the acetylcholine (ACh)-induced vascular relaxation, focusing on the protein-protein interaction involving kinin receptors with endothelial and neuronal nitric oxide synthases (eNOS and nNOS). Vascular reactivity, nitric oxide (NO·) and reactive oxygen species (ROS) generation, co-immunoprecipitation were assessed in thoracic aorta from male wild-type (WT), B1- (B1R−/−), B2- (B2R−/−) knockout mice. Some vascular reactivity experiments were also performed in a double kinin receptors knockout mice (B1B2R−/−). For pharmacological studies, selective B1- and B2-kinin receptors antagonists, NOS inhibitors and superoxide dismutase (SOD) mimetic were used. First, we show that B1- and B2-kinin receptors form heteromers with nNOS and eNOS in thoracic aorta. To investigate the functionality of these protein-protein interactions, we took advantage of pharmacological tools and knockout mice. Importantly, our results show that kinin receptors regulate ACh-induced relaxation via nNOS signaling in thoracic aorta with no changes in NO· donor-induced relaxation. Interestingly, B1B2R−/− presented similar level of vascular dysfunction as found in B1R−/− or B2R−/− mice. In accordance, aortic rings from B1R−/− or B2R−/− mice exhibit decreased NO· bioavailability and increased superoxide generation compared to WT mice, suggesting the involvement of excessive ROS generation in the endothelial dysfunction of B1R−/− and B2R−/− mice. Alongside, we show that impaired endothelial vasorelaxation induced by ACh in B1R−/− or B2R−/− mice was rescued by the SOD mimetic compound. Taken together, our findings show that B1- and B2-kinin receptors regulate the endothelium-dependent vasodilation of ACh through nNOS activity and indicate that molecular disturbance of short-range interaction between B1- and B2-kinin receptors with nNOS might be involved in the oxidative pathogenesis of endothelial dysfunction

<i>In vitro</i> effect of paraquat in aortic rings.

<p>Effects of <i>in vitro</i> treatment of endothelium-intact aortic rings with paraquat (5 µM) for 20 min on vasodilation induced by acetylcholine. The values are mean ± SE from five experiments. ***p<0.001.</p

L-NAME Treatment Enhances Exercise-induced Content of Myocardial Heat Shock Protein 72 (Hsp72) in Rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Background/Aim: Nitric oxide (NO) modulates the expression of the chaperone Hsp72 in the heart, and exercise stimulates both NO production and myocardial Hsp72 expression. The main purpose of the study was to investigate whether NO interferes with an exercise-induced myocardial Hsp72 expression. Methods: Male Wistar rats (70-100 days) were divided into control (C, n= 12), L-NAME-treated (L, n= 12), exercise (E, n= 13) and exercise plus L-NAME-treated (EL, n= 20) groups. L-NAME was given in drinking water (700 mg. L(-1)) and the exercise was performed on a treadmill (15-25 m.min(-1), 40-60 min. day(-1)) for seven days. Left ventricle (LV) protein Hsp content, NOS and phosphorylated-NOS (p-NOS) isoforms were measured using Western blotting. The activity of NOS was assayed in LV homogenates by the conversion of [(3)H] L-arginine to [(3)H] L-citrulline. Results: Hsp72 content was increased significantly (223%; p < 0.05) in the E group compared to the C group, but exercise alone did not alter the NOS content, p-NOS isoforms or NOS activity. Contrary to our expectation, L-NAME enhanced (p < 0.05) the exercise-induced Hsp72 content (EL vs. C, L and E groups = 1019%, 548% and 457%, respectively). Although the EL group had increased stimulatory p-eNOS(Ser1177) (over 200%) and decreased inhibitory p-nNOS(Ser852) (similar to 50%) compared to both the E and L groups (p < 0.05), NOS activity was similar in all groups. Conclusions: Our results suggest that exercise-induced cardiac Hsp72 expression does not depend on NO. Conversely, the in vivo L-NAME treatment enhances exercise-induced Hsp72 production. This effect may be due to an increase in cardiac stress. Copyright (C) 2011 S. Karger AG, Basel275479486Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundacao de Amparo a Pesquisa do Espirito Santo - Pronex (FAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq