Versican accumulation drives Nos2 induction and aortic disease in Marfan syndrome via Akt activation.

Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening condition associated with Marfan syndrome (MFS), a disease caused by fibrillin-1 gene mutations. While various conditions causing TAAD exhibit aortic accumulation of the proteoglycans versican (Vcan) and aggrecan (Acan), it is unclear whether these ECM proteins are involved in aortic disease. Here, we find that Vcan, but not Acan, accumulated in Fbn1C1041G/+ aortas, a mouse model of MFS. Vcan haploinsufficiency protected MFS mice against aortic dilation, and its silencing reverted aortic disease by reducing Nos2 protein expression. Our results suggest that Acan is not an essential contributor to MFS aortopathy. We further demonstrate that Vcan triggers Akt activation and that pharmacological Akt pathway inhibition rapidly regresses aortic dilation and Nos2 expression in MFS mice. Analysis of aortic tissue from MFS human patients revealed accumulation of VCAN and elevated pAKT-S473 staining. Together, these findings reveal that Vcan plays a causative role in MFS aortic disease in vivo by inducing Nos2 via Akt activation and identify Akt signaling pathway components as candidate therapeutic targets.

The Probiotic Lactobacillus fermentum Prevents Dysbiosis and Vascular Oxidative Stress in Rats with Hypertension Induced by Chronic Nitric Oxide Blockade.

SCOPE: Whether the probiotic Lactobacillus fermentum CECT5716 (LC40) ameliorates hypertension in rats with chronic nitric oxide (NO) synthase inhibition is tested. METHODS AND RESULTS: Rats are randomly divided into four different groups and treated for 4 weeks: a) vehicle (control), b) vehicle plus NG -nitro-l-arginine methyl ester (l-NAME; 50 mg 100 mL-1 in drinking water), c) LC40 (109 colony-forming units d-1 by gavage), and d) LC40 plus l-NAME. l-NAME induces gut dysbiosis, characterized mainly by an increased Fimicutes/Bacteroidetes (F/B) ratio and reduced Bifidobacterium content, increased Th17 cells and reduced Treg in mesenteric lymph nodes (MLN), increased aortic Th17 infiltration and reactive oxygen species, reduced aortic endothelium-dependent relaxant response to acetylcholine, and hypertension. LC40 prevents gut dysbiosis, alters the Th17/Treg balance in MLN, vascular oxidative stress, and inflammation, slightly improves endothelial dysfuncion but do not inhibit the development of l-NAME-induced hypertension. CONCLUSION: Chronic LC40 treatment, in this model of chronic inhibition of NO synthesis, reduces early events involved in atherosclerosis development, such as vascular oxidative stress and pro-inflammatory status, as a result of prevention of gut dysbiosis and immune changes in MLN, but not hypertension, confirming the critical role of NO in the antihypertensive effects of LC40 in genetic hypertension.

Protective vascular effects of quercitrin in acute TNBS-colitis in rats: the role of nitric oxide.

Quercitrin (quercetin 3-rhamnoside) is a bioflavonoid with anti-inflammatory activity in experimental colitis. Several studies have suggested that vascular injury might be a primary process in Crohn's disease, but there is no information about the function of the mesenteric bed in the experimental models of colitis. The aims of this study were to analyse whether the reactivity to vasoconstrictor agents is altered in the mesenteric vascular bed from animals with colitis induced by administration of trinitrobenzenesulfonic acid (TNBS) in the early stages of this pathology, and to determine the effects of quercitrin on such vascular alterations. Contraction of mesenteric beds produced by vasoconstrictor agents such as noradrenaline and KCl is reduced in rats in the early stages of experimental TNBS-induced colitis. This alteration was partially reverted by non-selective nitric oxide synthase (NOS) inhibition with N-nitro-l-arginine methylester, and enhanced by non-selective cyclooxygenase (COX) inhibition with indomethacin. However, the endothelium-dependent relaxant responses to acetylcholine were not significantly altered. iNOS, COX-2, NOX-1, tumor necrosis factor α (TNFα) and interleukin 1ß (IL1ß) expressions were higher in the mesenteric arteries from TNBS-treated rats, without changes in both eNOS expression and eNOS-Ser1177 phosphorylation. The in vivo pre-treatment with 5 mg kg-1 of the flavonoid quercitrin reverts both the early hyporesponse of mesenteric arteries to noradrenaline and the up-regulation of iNOS, COX2, NOX1, TNFα and IL1ß in colitic rats. In conclusion, quercitrin improves the impaired mesenteric vascular reactivity in the acute phase of this colitis model, at least in part by reducing NO overproduction from iNOS.

Role of UCP2 in the protective effects of PPARß/δ activation on lipopolysaccharide-induced endothelial dysfunction.

Bacterial endotoxin lipopolysaccharide (LPS) activates inflammatory pathways, induces cytokine expression in the endothelium, augments reactive oxygen species (ROS) production in the vascular wall, and induces endothelial dysfunction. The aim of the present study was to analyze the effects of peroxisome proliferator-activated receptor (PPAR)ß/δ activation on LPS-induced inflammation, oxidative stress and endothelial dysfunction and to determine whether uncoupling protein-2 (UCP2) plays a role in these effects. In vivo, the PPARß/δ agonist GW0742 treatment prevented the LPS-induced reduction in aortic relaxation, the increase in vascular ROS production, the upregulation of NOX1, NOX2, p47(phox), and p22(phox) mRNA levels, and the endoplasmic reticulum (ER) stress markers in mice. We show that in mouse aortic endothelial cells (MAECs), GW0742 prevented the decreased A23187-stimulated nitric oxide (NO) production, and the increased intracellular ROS levels caused by exposure to LPS in vitro. The PPARß/δ antagonist GSK0660 abolished all these in vivo and in vitro protective effects induced by GW0742. This agonist also restored the reduced expression of UCP2 and mitofusin-2 induced by LPS. The effects of GW0742 on NO and ROS production in MAEC exposed to LPS were abolished by the UCP2 inhibitor genipin or by siRNA targeting UCP-2. Genipin also suppressed the expressional changes on NADPH oxidase and ER stress markers induced by GW0742. In conclusion, PPARß/δ activation restored the LPS-induced endothelial dysfunction by upregulation of UCP2, with the subsequent alleviation of ER stress and NADPH oxidase activity, thus reducing intracellular ROS production and increasing NO bioavailability.

Chronic peroxisome proliferator-activated receptorß/δ agonist GW0742 prevents hypertension, vascular inflammatory and oxidative status, and endothelial dysfunction in diet-induced obesity.

OBJECTIVE: Endothelial dysfunction plays a key role in obesity-induced risk of cardiovascular disease. The aim of the present study was to analyze the effect of chronic peroxisome proliferator-activated receptor (PPAR)ß/δ agonist GW0742 treatment on endothelial function in obese mice fed a high-fat diet (HFD). METHODS AND RESULTS: Five-week-old male mice were allocated to one of the following groups: control, control-treated (GW0742, 3 mg/kg per day, by oral gavage), HFD, HFD + GW0742, HFD + GSK0660 (1 mg/kg/day, intraperitoneal) or HFD-GW0742-GSK0660 and followed for 11 or 13 weeks. GW0742 administration to mice fed HFD prevented the gain of body weight, heart and kidney hypertrophy, and fat accumulation. The increase in plasma levels of fasting glucose, glucose tolerance test, homeostatic model assessment of insulin resistance, and triglyceride found in the HFD group was suppressed by GW0742. This agonist increased plasma HDL in HFD-fed mice and restored the levels of tumor necrosis factor-α and adiponectin in fat. GW0742 prevented the impaired nitric oxide-dependent vasodilatation induced by acetylcholine in aortic rings from mice fed HFD. Moreover, GW0742 increased both aortic Akt and endothelial nitric oxide synthase phosphorylation, and inhibited the increase in caveolin-1/endothelial nitric oxide synthase interaction, ethidium fluorescence, NOX-1, Toll-like receptor 4, tumor necrosis factor-α, and interleukin-6 expression, and IκBα phosphorylation found in aortae from the HFD group. GSK0660 prevented all changes induced by GW0742. CONCLUSION: PPARß/δ activation prevents obesity and exerts protective effects on hypertension and on the early manifestations of atherosclerosis, that is, endothelial dysfunction and the vascular pro-oxidant and pro-inflammatory status, in HFD-fed mice.

The probiotic Lactobacillus coryniformis CECT5711 reduces the vascular pro-oxidant and pro-inflammatory status in obese mice.

Obesity is associated with intestine dysbiosis and is characterized by a low-grade inflammatory status, which affects vascular function. In the present study, we evaluated the effects of a probiotic with immunomodulatory properties, Lactobacillus coryniformis CECT5711, in obese mice fed on an HFD (high-fat diet). The probiotic treatment was given for 12 weeks, and it did not affect the weight evolution, although it reduced basal glycaemia and insulin resistance. L. coryniformis administration to HFD-induced obese mice induced marked changes in microbiota composition and reduced the metabolic endotoxaemia as it decreased the LPS (lipopolysaccharide) plasma level, which was associated with a significant improvement in gut barrier disruption. Furthermore, it lowered TNFα (tumour necrosis factor α) expression in liver, improving the inflammatory status, and thus the glucose metabolism. Additionally, the probiotic reversed the endothelial dysfunction observed in obese mice when endothelium- and NO (nitric oxide)-dependent vasodilatation induced by acetylcholine in aortic rings was studied. It also restored the increased vessel superoxide levels observed in obese mice, by reducing NADPH oxidase activity and increasing antioxidant enzymes. Moreover, chronic probiotic administration for 2 weeks also improved endothelial dysfunction and vascular oxidative stress induced by in vivo administration of LPS in control mice fed on a standard chow diet. The results of the present study demonstrate an endothelial-protective effect of L. coryniformis CECT5711 in obese mice by increasing NO bioavailability, suggesting the therapeutic potential of this gut microbiota manipulation to prevent vasculopathy in obesity.