Sirtuin1 protects endothelial Caveolin-1 expression and preserves endothelial function via suppressing miR-204 and endoplasmic reticulum stress.

Sirtuin1 (Sirt1) is a class III histone deacetylase that regulates a variety of physiological processes, including endothelial function. Caveolin1 (Cav1) is also an important determinant of endothelial function. We asked if Sirt1 governs endothelial Cav1 and endothelial function by regulating miR-204 expression and endoplasmic reticulum (ER) stress. Knockdown of Sirt1 in endothelial cells, and in vivo deletion of endothelial Sirt1, induced endothelial ER stress and miR-204 expression, reduced Cav1, and impaired endothelium-dependent vasorelaxation. All of these effects were reversed by a miR-204 inhibitor (miR-204 I) or with overexpression of Cav1. A miR-204 mimic (miR-204 M) decreased Cav1 in endothelial cells. In addition, high-fat diet (HFD) feeding induced vascular miR-204 and reduced endothelial Cav1. MiR-204-I protected against HFD-induced downregulation of endothelial Cav1. Moreover, pharmacologic induction of ER stress with tunicamycin downregulated endothelial Cav1 and impaired endothelium-dependent vasorelaxation that was rescued by overexpressing Cav1. In conclusion, Sirt1 preserves Cav1-dependent endothelial function by mitigating miR-204-mediated vascular ER stress

Efectos de pravastatina en la disfunción endotelial, estrés oxidativo y otros parámetros cardiovasculares

[EN] Pravastatin, used to lower cholesterol levels, also has independent effects of lipid-lowering action. We study the effects of administration of 20 mg / kg / day of this statin for four weeks, in rats with different degrees of hypertension (spontaneously hypertensive rats, SHR). Pravastatin had no effect on systolic blood pressure in normotensive controls (WKY), prevented the rise in incipient hypertensive SHR decreased it slightly but significantly in SHR with established hypertension. Cholesterol levels were unchanged in either group. The treatment improved endothelial function of conductance arteries (aorta) and resistance (mesenteric, renal vascular bed). This effect was accompanied by an increase in the levels of NO and eNOS expression and a reduction in the expression of COX-2. In addition, the oxidative state generated cushioned by high reducing superoxide anion production stimulated by NADPH oxidase. The evaluation of morphological and histological parameters indicates that vascular remodeling caused by hypertension improved significantly after treatment. Pravastatin reduced cardiac hypertrophy, cardiomyocyte size and collagen deposition. The analysis of markers involved in fibrotic processes indicates a reduction in the expression of collagen I, fibronectin and PAI-1. Additional experiments performed quimiolumiscencia functionality and in aortic rings of SHR and Wistar indicate that the antioxidant action of pravastatin is involved, besides the inhibition of NADPH oxidase, an effect scavenger. In human arteries from patients undergoing coronary bypass surgery, incubation with pravastatin improved endothelium-dependent response and reduced the response to thromboxane and superoxide radical production. These results indicate that pravastatin, irrespective of their cholesterol-lowering effect could be beneficial in cardiovascular diseases.[ES] La pravastatina, usada para disminuir los niveles de colesterol, posee también efectos independientes de su acción hipolipemiante. En este trabajo estudiamos los efectos de la administración de 20 mg/kg/día de esta estatina, durante cuatro semanas, en ratas con diferente grado de hipertensión (ratas espontáneamente hipertensas, SHR). Pravastatina no tuvo efecto sobre la presión arterial sistólica en controles normotensos (WKY), impidió la subida en SHR con hipertensión incipiente y la redujo, ligera pero significativamente, en SHR con hipertensión establecida. Los niveles de colesterol no se modificaron en ninguno de los grupos. El tratamiento mejoró la función endotelial en arterias de conductancia (aorta) y de resistencia (mesentéricas, lecho vascular renal). Este efecto se acompañó de un incremento en los niveles de NO y en la expresión de eNOS, y una reducción en la expresión de COX-2. Además, amortiguó el estado oxidativo generado por la hipertensión reduciendo la producción de aniones superóxido estimulada por NADPH-oxidasa. La valoración de parámetros morfo-histológicos indica que el remodelado vascular causado por la hipertensión mejoró significativamente tras el tratamiento. Pravastatina redujo la hipertrofia cardiaca, el tamaño de los cardiomiocitos y la deposición de colágeno. El análisis de marcadores implicados en los procesos fibróticos indica una reducción en la expresión de colágeno I, fibronectina y PAI-1. Experimentos adicionales de funcionalidad y quimiolumiscencia realizados en anillos de aorta de SHR y Wistar indican que en la acción antioxidante de pravastatina interviene, además de la inhibición de la NADPH oxidasa, un efecto "scavenger". En arterias humanas procedentes de pacientes sometidos a cirugía de bypass coronario, la incubación con pravastatina mejoró la respuesta endotelio-dependiente y redujo la respuesta a tromboxano y la producción de radicales superóxido. Estos resultados nos indican que pravastatina, independientemente de su efecto hipolipemiante, podría resultar beneficiosa en patologías cardiovasculares

The Beneficial Effect of Lomitapide on the Cardiovascular System in LDLr^−/− Mice with Obesity

Objectives: Homozygous familial hypercholesteremia (HoFH) is a rare, life-threatening metabolic disease, mainly caused by a mutation in the LDL receptor. If untreated, HoFH causes premature death from acute coronary syndrome. Lomitapide is approved by the FDA as a therapy to lower lipid levels in adult patients with HoFH. Nevertheless, the beneficial effect of lomitapide in HoFH models remains to be defined. In this study, we investigated the effect of lomitapide on cardiovascular function using LDL receptor-knockout mice (LDLr−/−). Methods: Six-week-old LDLr−/− mice were fed a standard diet (SD) or a high-fat diet (HFD) for 12 weeks. Lomitapide (1 mg/Kg/Day) was given by oral gavage for the last 2 weeks in the HFD group. Body weight and composition, lipid profile, blood glucose, and atherosclerotic plaques were measured. Vascular reactivity and markers for endothelial function were determined in conductance arteries (thoracic aorta) and resistance arteries (mesenteric resistance arteries (MRA)). Cytokine levels were measured by using the Mesoscale discovery V-Plex assays. Results: Body weight (47.5 ± 1.5 vs. 40.3 ± 1.8 g), % of fat mass (41.6 ± 1.9% vs. 31.8 ± 1.7%), blood glucose (215.5 ± 21.9 vs. 142.3 ± 7.7 mg/dL), and lipid levels (cholesterol: 600.9 ± 23.6 vs. 451.7 ± 33.4 mg/dL; LDL/VLDL: 250.6 ± 28.9 vs. 161.1 ± 12.24 mg/dL; TG: 299.5 ± 24.1 vs. 194.1 ± 28.1 mg/dL) were significantly decreased, and the % of lean mass (56.5 ± 1.8% vs. 65.2 ± 2.1%) was significantly increased in the HFD group after lomitapide treatment. The atherosclerotic plaque area also decreased in the thoracic aorta (7.9 ± 0.5% vs. 5.7 ± 0.1%). After treatment with lomitapide, the endothelium function of the thoracic aorta (47.7 ± 6.3% vs. 80.7 ± 3.1%) and mesenteric resistance artery (66.4 ± 4.3% vs. 79.5 ± 4.6%) was improved in the group of LDLr−/− mice on HFD. This was correlated with diminished vascular endoplasmic (ER) reticulum stress, oxidative stress, and inflammation. Conclusions: Treatment with lomitapide improves cardiovascular function and lipid profile and reduces body weight and inflammatory markers in LDLr−/− mice on HFD

Protective Role of Short-Chain Fatty Acids against Ang- II-Induced Mitochondrial Dysfunction in Brain Endothelial Cells: A Potential Role of Heme Oxygenase 2

Objectives: Short-chain fatty acids (SCFAs), the main metabolites released from the gut microbiota, are altered during hypertension and obesity. SCFAs play a beneficial role in the cardiovascular system. However, the effect of SCFAs on cerebrovascular endothelial cells is yet to be uncovered. In this study, we use brain endothelial cells to investigate the in vitro effect of SCFAs on heme oxygenase 2 (HO-2) and mitochondrial function after angiotensin II (Ang-II) treatment. Methods: Brain human microvascular endothelial cells were treated with Ang-II (500 nM for 24 h) in the presence and absence of an SCFAs cocktail (1 μM; acetate, propionate, and butyrate) and/or HO-2 inhibitor (SnPP 5 μM). At the end of the treatment, HO-2, endothelial markers (p-eNOS and NO production), inflammatory markers (TNFα, NFκB-p50, and -p65), calcium homeostasis, mitochondrial membrane potential, mitochondrial ROS and H2O2, and mitochondrial respiration were determined in all groups of treated cells. Key Results: Our data showed that SCFAs rescued HO-2 after Ang-II treatment. Additionally, SCFAs rescued Ang-II-induced eNOS reduction and mitochondrial membrane potential impairment and mitochondrial respiration damage. On the other hand, SCFAs reduced Ang-II-induced inflammation, calcium dysregulation, mitochondrial ROS, and H2O2. All of the beneficial effects of SCFAs on endothelial cells and mitochondrial function occurred through HO-2. Conclusions: SCFAs treatment restored endothelial cells and mitochondrial function following Ang-II-induced oxidative stress. SCFAs exert these beneficial effects by acting on HO-2. Our results are opening the door for more studies to investigate the effect the of SCFAs/HO-2 axis on hypertension and obesity-induced cerebrovascular diseases

Sirtuin1 protects endothelial Caveolin-1 expression and preserves endothelial function via suppressing miR-204 and endoplasmic reticulum stress.

Sirtuin1 (Sirt1) is a class III histone deacetylase that regulates a variety of physiological processes, including endothelial function. Caveolin1 (Cav1) is also an important determinant of endothelial function. We asked if Sirt1 governs endothelial Cav1 and endothelial function by regulating miR-204 expression and endoplasmic reticulum (ER) stress. Knockdown of Sirt1 in endothelial cells, and in vivo deletion of endothelial Sirt1, induced endothelial ER stress and miR-204 expression, reduced Cav1, and impaired endothelium-dependent vasorelaxation. All of these effects were reversed by a miR-204 inhibitor (miR-204 I) or with overexpression of Cav1. A miR-204 mimic (miR-204 M) decreased Cav1 in endothelial cells. In addition, high-fat diet (HFD) feeding induced vascular miR-204 and reduced endothelial Cav1. MiR-204-I protected against HFD-induced downregulation of endothelial Cav1. Moreover, pharmacologic induction of ER stress with tunicamycin downregulated endothelial Cav1 and impaired endothelium-dependent vasorelaxation that was rescued by overexpressing Cav1. In conclusion, Sirt1 preserves Cav1-dependent endothelial function by mitigating miR-204-mediated vascular ER stress

Enhanced endoplasmic reticulum and mitochondrial stress in abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a degenerative vascular disease with a complex aetiology that remains to be fully elucidated. Clinical management of AAA is limited to surgical repair, while an effective pharmacotherapy is still awaited. Endoplasmic reticulum (ER) stress and mitochondrial dysfunction have been involved in the pathogenesis of cardiovascular diseases (CVDs), although their contribution to AAA development is uncertain. Therefore, we aimed to determine their implication in AAA and investigated the profile of oxysterols in plasma, specifically 7-ketocholesterol (7-KC), as an ER stress inducer.In the present study, we determined aortic ER stress activation in a large cohort of AAA patients compared with healthy donors. Higher gene expression of activating transcription factor (ATF) 6 (ATF6), IRE-1, X-binding protein 1 (XBP-1), C/EBP-homologous protein (CHOP), CRELD2 and suppressor/enhancer of Lin-12-like (SEL1L) and greater protein levels of active ATF6, active XBP1 and of the pro-apoptotic protein CHOP were detected in human aneurysmatic samples. This was accompanied by an exacerbated apoptosis, higher reactive oxygen species (ROS) production and by a reduction in mitochondrial biogenesis in the vascular wall of AAA. The quantification of oxysterols, performed by liquid chromatography-(atmospheric pressure chemical ionization (APCI))-mass spectrometry, showed that levels of 7-KC were significantly higher while those of 7α-hydroxycholesterol (HC), 24-HC and 27-HC were lower in AAA patients compared with healthy donors. Interestingly, the levels of 7-KC correlate with the expression of ER stress markers.Our results evidence an induction of ER stress in the vascular wall of AAA patients associated with an increase in circulating 7-KC levels and a reduction in mitochondrial biogenesis suggesting their implication in the pathophysiology of this disease.This work was supported by the Spanish Ministerio de Economía y Competitividad (MINECO)-Instituto de Salud Carlos III (ISCIII) [grant numbers CP15/00126, PI17/08137 (to M.G.), PI18/0919 (to C.R.) and RTI2018-094727-B-100 (to J.M.G.)]; the CIBERCV [grant number CB16/11/00257]; the ISCIII, Miguel Servet I program (grant number CP15/00126 (to M.N.M. and M.G.)]; and by Agencia de Gestio d’Ajuts Universitaris i de Recerca (AGAUR; program of support to Research Groups. Ref. 2017-SGR-00333). The study was co-founded by Fondo Europeo de Desarrollo Regional (FEDER)-The way to build Europ