Michala Varejckova

High soluble endoglin levels do not induce endothelial dysfunction in mouse aorta.

Increased levels of a soluble form of endoglin (sEng) circulating in plasma have been detected in various pathological conditions related to cardiovascular system. High concentration of sEng was also proposed to contribute to the development of endothelial dysfunction, but there is no direct evidence to support this hypothesis. Therefore, in the present work we analyzed whether high sEng levels induce endothelial dysfunction in aorta by using transgenic mice with high expression of human sEng. Transgenic mice with high expression of human sEng on CBAxC57Bl/6J background (Sol-Eng +) and age-matched transgenic littermates that do not develop high levels of human soluble endoglin (control animals in this study) on chow diet were used. As expected, male and female Sol-Eng + transgenic mice showed higher levels of plasma concentrations of human sEng as well as increased blood arterial pressure, as compared to control animals. Functional analysis either in vivo or ex vivo in isolated aorta demonstrated that the endothelium-dependent vascular function was similar in Sol-Eng + and control mice. In addition, Western blot analysis showed no differences between Sol-Eng + and control mice in the protein expression levels of endoglin, endothelial NO-synthase (eNOS) and pro-inflammatory ICAM-1 and VCAM-1 from aorta. Our results demonstrate that high levels of soluble endoglin alone do not induce endothelial dysfunction in Sol-Eng + mice. However, these data do not rule out the possibility that soluble endoglin might contribute to alteration of endothelial function in combination with other risk factors related to cardiovascular disorders.

High Levels of Soluble Endoglin Induce a Proinflammatory and Oxidative-Stress Phenotype Associated with Preserved NO-Dependent Vasodilatation in Aortas from Mice Fed a High-Fat Diet

Aims: A soluble form of endoglin (sEng) was proposed to participate in the induction of endothelial dysfunction in small blood vessels. Here, we tested the hypothesis that high levels of sEng combined with a high-fat diet induce endothelial dysfunction in an atherosclerosis-prone aorta. Methods and Results: Six-month-old female and male transgenic mice overexpressing human sEng (Sol-Eng+) with low (Sol-Eng+low) or high (Sol-Eng+high) levels of plasma sEng were fed a high-fat rodent diet containing 1.25% cholesterol and 40% fat for 3 months. The plasma cholesterol and mouse sEng levels did not differ in the Sol-Eng+high and Sol-Eng+low mice. The expression of proinflammatory (P-selectin, ICAM-1, pNFκB and COX-2) and oxidative-stress-related markers (HO-1, NOX-1 and NOX-2) in the aortas of Sol-Eng+high female mice was significantly higher than in Sol-Eng+low female mice. Endothelium-dependent vasodilatation induced by acetylcholine was preserved better in the Sol-Eng+ high female mice than in the Sol-Eng+low female mice. Conclusion: These results suggest that high concentrations of sEng in plasma in combination with a high-fat diet induce the simultaneous activation of proinflammatory, pro-oxidative and vasoprotective mechanisms in mice aorta and the balance of these biological processes determines whether the final endothelial phenotype is adaptive or maladaptive.

Soluble endoglin modulates the pro-inflammatory mediators NF-κB and IL-6 in cultured human endothelial cells

Aims: Endoglin is a transmembrane glycoprotein, that plays an important role in regulating endothelium. Proteolytic cleavage of membrane endoglin releases soluble endoglin (sEng), whose increased plasma levels have been detected in diseases related to the cardiovascular system. It was proposed that sEng might damage vascular endothelium, but detailed information about the potential mechanisms involved is not available. Thus, we hypothesized that sEng contributes to endothelial dysfunction, leading to a pro‐inflammatory phenotype by a possible modulation of the TGF‐&bgr; and/or inflammatory pathways. Main methods: Human umbilical vein endothelial cells (HUVECs) and Human embryonic kidney cell line (HEK293T) were treated with different sEng concentration and time in order to reveal possible effect on biomarkers of inflammation and TGF‐&bgr; signaling. IL6 and NF&kgr;B reporter luciferase assays, quantitative real‐time PCR analysis, Western blot analysis and immunofluorescence flow cytometry were used. Key findings: sEng treatment results in activation of NF‐&kgr;B/IL‐6 expression, increased expression of membrane endoglin and reduced expression of Id‐1. On the other hand, no significant effects on other markers of endothelial dysfunction and inflammation, including eNOS, peNOSS1177, VCAM‐1, COX‐1, COX‐2 and ICAM‐1 were detected. Significance: As a conclusion, sEng treatment resulted in an activation of NF‐&kgr;B, IL‐6, suggesting activation of pro‐inflammatory phenotype in endothelial cells. The precise mechanism of this activation and its consequence remains to be elucidated. A combined treatment of sEng with other cardiovascular risk factors will be necessary in order to reveal whether sEng is not only a biomarker of cardiovascular diseases, but also a protagonist of endothelial dysfunction.

Endoglin is crucial for atorvastatin induced eNOS expression in endothelial cells in vitro

Introduction and aims: Endoglin, a 180 kDa membrane glycoprotein, is a TGF-beta co-receptor which is overexpressed in several models of chronic kidney disease but its specific function in renal fibrosis remains still undefined. Two membrane isoforms generated by alternative splicing have been described, full length Endoglin (L-Eng, the most abundant isoform) and S-Endoglin (short) that differ from L-Eng in the absence of the cytoplasmic tail. We have recently demonstrated that L-Eng overexpression enhances fibrosis in the unilateral ureteral obstruction (UUO) model of kidney fibrosis. The aim of the present study was to assess the effect of S-Endoglin overexpression in renal tubulo-interstitial fibrosis induced by unilateral ureteral obstruction (UUO). Methods: For this purpose, a transgenic mouse which ubiquitously overexpresses human S-Endoglin (SENG+) was generated. UUO was performed in S-ENG+ mice and their wild type littermates. Kidney Fibrosis was determined by morphometric techniques and by the expression of fibrosis-related molecules (collagen I, fibronectin) by western blot. Results: Obstructed kidneys from S-ENG+ mice showed reduced tubulo-interstitial fibrotic area and lower amounts of collagen I and fibronectin than obstructed kidneys from WT mice. Moreover, western blot analysis showed that levels of p-Smad1 and p-Smad3 were higher in obstructed kidneys, being these increase significantly lower in obstructed kidneys from S-ENG+ than in those from WT animals. Conclusions: The overexpression of S-ENG reduces kidney fibrosis. These results are exactly the opposite of those obtained in L-ENG mice. Therefore, we conclude that the intracellular domain of endoglin plays a major role in regulating its fibrotic effects.1Department of Biological and Medical Sciences, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic; 2Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic; 3Centro de Investigaciones Biologicas, Consejo Superior de Investigaciones Científicas (CSIC), and Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), Madrid, Spainendoglin release upon vascular injury Bernabeu C1; Gallardo-Vara E1; Blanco F1; Roque M2; Friedman SL3; Suzuki T4; Botella LM1 1Centro de Investigaciones Biológicas, CSIC, and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28040 Madrid, Spain; 2Servei de Cardiología, Institut del Torax, Hospital Clinic, Barcelona, Spain; 3Division of Liver Disease, Mount Sinai School of Medicine, New York, NY, USA; 4Department of Cardiovascular Medicine, The University of Tokyo, Tokyo, Japan11th International HHT Scientific Conference June 11–14, 2015 Captiva, Florida USA Springer Science+Business Media Dordrecht 2015 SCIENTIFIC PROGRAM COMMITTEE