Science.gov

Sample records for endothelial barrier function

  1. [Vascular endothelial Barrier Function].

    PubMed

    Ivanov, A N; Puchinyan, D M; Norkin, I A

    2015-01-01

    Endothelium is an important regulator of selective permeability of the vascular wall for different molecules and cells. This review summarizes current data on endothelial barrier function. Endothelial glycocalyx structure, its function and role in the molecular transport and leukocytes migration across the endothelial barrier are discussed. The mechanisms of transcellular transport of macromolecules and cell migration through endothelial cells are reviewed. Special section of this article addresses the structure and function of tight and adherens endothelial junction, as well as their importance for the regulation of paracellular transport across the endothelial barrier. Particular attention is paid to the signaling mechanism of endothelial barrier function regulation and the factors that influence on the vascular permeability.

  2. Blood cells and endothelial barrier function

    PubMed Central

    Rodrigues, Stephen F; Granger, D Neil

    2015-01-01

    Abstract The barrier properties of endothelial cells are critical for the maintenance of water and protein balance between the intravascular and extravascular compartments. An impairment of endothelial barrier function has been implicated in the genesis and/or progression of a variety of pathological conditions, including pulmonary edema, ischemic stroke, neurodegenerative disorders, angioedema, sepsis and cancer. The altered barrier function in these conditions is often linked to the release of soluble mediators from resident cells (e.g., mast cells, macrophages) and/or recruited blood cells. The interaction of the mediators with receptors expressed on the surface of endothelial cells diminishes barrier function either by altering the expression of adhesive proteins in the inter-endothelial junctions, by altering the organization of the cytoskeleton, or both. Reactive oxygen species (ROS), proteolytic enzymes (e.g., matrix metalloproteinase, elastase), oncostatin M, and VEGF are part of a long list of mediators that have been implicated in endothelial barrier failure. In this review, we address the role of blood borne cells, including, neutrophils, lymphocytes, monocytes, and platelets, in the regulation of endothelial barrier function in health and disease. Attention is also devoted to new targets for therapeutic intervention in disease states with morbidity and mortality related to endothelial barrier dysfunction. PMID:25838983

  3. Novel regulators of endothelial barrier function

    PubMed Central

    Ravindran, Krishnan; Kuebler, Wolfgang M.

    2014-01-01

    Endothelial barrier function is an essential and tightly regulated process that ensures proper compartmentalization of the vascular and interstitial space, while allowing for the diffusive exchange of small molecules and the controlled trafficking of macromolecules and immune cells. Failure to control endothelial barrier integrity results in excessive leakage of fluid and proteins from the vasculature that can rapidly become fatal in scenarios such as sepsis or the acute respiratory distress syndrome. Here, we highlight recent advances in our understanding on the regulation of endothelial permeability, with a specific focus on the endothelial glycocalyx and endothelial scaffolds, regulatory intracellular signaling cascades, as well as triggers and mediators that either disrupt or enhance endothelial barrier integrity, and provide our perspective as to areas of seeming controversy and knowledge gaps, respectively. PMID:25381026

  4. Role of microtubule cytoskeleton in regulation of endothelial barrier function.

    PubMed

    Alieva, I B

    2014-09-01

    Cytoplasmic microtubules are an obligatory component of the cytoskeleton of all types of cells. Microtubules are involved in many cellular processes including directed transport of vesicles and signaling molecules and changes in cell shape during its spreading, polarization, and movement. The intracellular organization of the system of microtubules and their dynamic properties are different in different types of cells because they play a key role in the implementation of a variety of cell and tissue functions, including the regulation of the endothelial barrier function. This review presents an overview of current studies on the properties of endothelial microtubules, their interaction with other components of the cytoskeleton and cell adhesion structures, and the role of microtubules in the regulation of the endothelial barrier function.

  5. Neddylated Cullin 3 is required for vascular endothelial-cadherin-mediated endothelial barrier function.

    PubMed

    Sakaue, Tomohisa; Fujisaki, Ayako; Nakayama, Hironao; Maekawa, Masashi; Hiyoshi, Hiromi; Kubota, Eiji; Joh, Takashi; Izutani, Hironori; Higashiyama, Shigeki

    2017-02-01

    Vascular endothelial (VE)-cadherin, a major endothelial adhesion molecule, regulates vascular permeability, and increased vascular permeability has been observed in several cancers. The aim of this study was to elucidate the role of the NEDD8-Cullin E3 ligase, in maintaining barrier permeability. To this end, we investigated the effects of the inhibition of Cullin E3 ligases, by using inhibitors and knockdown techniques in HUVECs. Furthermore, we analyzed the mRNA and protein levels of the ligases by quantitative RT-PCR and Western blotting, respectively. The results revealed that NEDD8-conjugated Cullin 3 is required for VE-cadherin-mediated endothelial barrier functions. Treatment of HUVECs with MLN4924, a chemical inhibitor of the NEDD8-activating enzyme, led to high vascular permeability due to impaired cell-cell contact. Similar results were obtained when HUVECs were treated with siRNA directed against Cullin 3, one of the target substrates of NEDD8. Immunocytochemical staining showed that both treatments equally depleted VE-cadherin protein localized at the cell-cell borders. However, quantitative RT-PCR showed that there was no significant difference in the VE-cadherin mRNA levels between the treatment and control groups. In addition, cycloheximide chase assay revealed that the half-life of VE-cadherin protein was dramatically reduced by Cullin 3 depletion. Together, these findings suggest that neddylated Cullin 3 plays a crucial role in endothelial cell barrier function by regulating VE-cadherin. © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  6. Update on pulmonary edema: the role and regulation of endothelial barrier function.

    PubMed

    Patterson, C E; Lum, H

    2001-01-01

    Discovery of the pathophysiologic mechanisms leading to pulmonary edema and identification of effective strategies for prevention remain significant clinical concerns. Endothelial barrier function is a key component for maintenance of the integrity of the vascular boundary in the lung, particularly since the gas exchange surface area of the alveolar-capillary membrane is large. This review is focused on new insights in the pulmonary endothelial response to injury and recovery, reversible activation by edemagenic agents, and the biochemical/structural basis for regulation of endothelial barrier function. This information is discussed in the context of fundamental concepts of lung fluid balance and pulmonary function.

  7. Rab11a Mediates Vascular Endothelial-Cadherin Recycling and Controls Endothelial Barrier Function.

    PubMed

    Yan, Zhibo; Wang, Zhen-Guo; Segev, Nava; Hu, Sanyuan; Minshall, Richard D; Dull, Randal O; Zhang, Meihong; Malik, Asrar B; Hu, Guochang

    2016-02-01

    Vascular endothelial (VE)-cadherin is the predominant component of endothelial adherens junctions essential for cell-cell adhesion and formation of the vascular barrier. Endocytic recycling is an important mechanism for maintaining the expression of cell surface membrane proteins. However, little is known about the molecular mechanism of VE-cadherin recycling and its role in maintenance of vascular integrity. Using calcium-switch assay, confocal imaging, cell surface biotinylation, and flow cytometry, we showed that VE-cadherin recycling required Ras-related proteins in brain (Rab)11a and Rab11 family-interacting protein 2. Yeast 2-hybrid assay and coimmunoprecipitation demonstrated that direct interaction of VE-cadherin with family-interacting protein 2 (at aa 453-484) formed a ternary complex with Rab11a in human endothelial cells. Silencing of Rab11a or Rab11 family-interacting protein 2 in endothelial cells prevented VE-cadherin recycling and VE-cadherin expression at endothelial plasma membrane. Furthermore, inactivation of Rab11a signaling blocked junctional reannealing after vascular inflammation. Selective knockdown of Rab11a in pulmonary microvessels markedly increased vascular leakage in mice challenged with lipopolysaccharide or polymicrobial sepsis. Rab11a/Rab11 family-interacting protein 2-mediated VE-cadherin recycling is required for formation of adherens junctions and restoration of VE barrier integrity and hence a potential target for clinical intervention in inflammatory disease. © 2015 American Heart Association, Inc.

  8. Actin dynamics in the regulation of endothelial barrier functions and neutrophil recruitment during endotoxemia and sepsis.

    PubMed

    Schnoor, Michael; García Ponce, Alexander; Vadillo, Eduardo; Pelayo, Rosana; Rossaint, Jan; Zarbock, Alexander

    2017-02-02

    Sepsis is a leading cause of death worldwide. Increased vascular permeability is a major hallmark of sepsis. Dynamic alterations in actin fiber formation play an important role in the regulation of endothelial barrier functions and thus vascular permeability. Endothelial integrity requires a delicate balance between the formation of cortical actin filaments that maintain endothelial cell contact stability and the formation of actin stress fibers that generate pulling forces, and thus compromise endothelial cell contact stability. Current research has revealed multiple molecular pathways that regulate actin dynamics and endothelial barrier dysfunction during sepsis. These include intracellular signaling proteins of the small GTPases family (e.g., Rap1, RhoA and Rac1) as well as the molecules that are directly acting on the actomyosin cytoskeleton such as myosin light chain kinase and Rho kinases. Another hallmark of sepsis is an excessive recruitment of neutrophils that also involves changes in the actin cytoskeleton in both endothelial cells and neutrophils. This review focuses on the available evidence about molecules that control actin dynamics and regulate endothelial barrier functions and neutrophil recruitment. We also discuss treatment strategies using pharmaceutical enzyme inhibitors to target excessive vascular permeability and leukocyte recruitment in septic patients.

  9. Effects of Fe particle irradiation on human endothelial barrier structure and function

    NASA Astrophysics Data System (ADS)

    Sharma, Preety; Guida, Peter; Grabham, Peter

    2014-07-01

    Space travel involves exposure to biologically effective heavy ion radiation and there is consequently a concern for possible degenerative disorders in humans. A significant target for radiation effects is the microvascular system, which is crucial to healthy functioning of the tissues. Its pathology is linked to disrupted endothelial barrier function and is not only a primary event in a range of degenerative diseases but also an important influencing factor in many others. Thus, an assessment of the effects of heavy ion radiation on endothelial barrier function would be useful for estimating the risks of space travel. This study was aimed at understanding the effects of high LET Fe particles (1 GeV/n) and is the first investigation of the effects of charged particles on the function of the human endothelial barrier. We used a set of established and novel endpoints to assess barrier function after exposure. These include, trans-endothelial electrical resistance (TEER), morphological effects, localization of adhesion and cell junction proteins (in 2D monolayers and in 3D tissue models), and permeability of molecules through the endothelial barrier. A dose of 0.50 Gy was sufficient to cause a progressive reduction in TEER measurements that were significant 48 hours after exposure. Concurrently, there were morphological changes and a 14% loss of cells from monolayers. Gaps also appeared in the normally continuous cell-border localization of the tight junction protein - ZO-1 but not the Platelet endothelial cell adhesion molecule (PECAM-1) in both monolayers and in 3D vessel models. Disruption of barrier function was confirmed by increased permeability to 3 kDa and 10 kDa dextran molecules. A dose of 0.25 Gy caused no detectible change in cell number, morphology, or TEER, but did cause barrier disruption since there were gaps in the cell border localization of ZO-1 and an increased permeability to 3 kDa dextran. These results indicate that Fe particles potently have

  10. Biosensor Technology Reveals the Disruption of the Endothelial Barrier Function and the Subsequent Death of Blood Brain Barrier Endothelial Cells to Sodium Azide and Its Gaseous Products.

    PubMed

    Kho, Dan T; Johnson, Rebecca H; O'Carroll, Simon J; Angel, Catherine E; Graham, E Scott

    2017-09-21

    Herein we demonstrate the sensitive nature of human blood-brain barrier (BBB) endothelial cells to sodium azide and its gaseous product. Sodium azide is known to be acutely cytotoxic at low millimolar concentrations, hence its use as a biological preservative (e.g., in antibodies). Loss of barrier integrity was noticed in experiments using Electric Cell-substrate Impedance Sensing (ECIS) biosensor technology, to measure endothelial barrier integrity continuously in real-time. Initially the effect of sodium azide was observed as an artefact where it was present in antibodies being employed in neutralisation experiments. This was confirmed where antibody clones that were azide-free did not mediate loss of barrier function. A delayed loss of barrier function in neighbouring wells implied the influence of a liberated gaseous product. ECIS technology demonstrated that the BBB endothelial cells had a lower level of direct sensitivity to sodium azide of ~3 µM. Evidence of gaseous toxicity was consistently observed at 30 µM and above, with disrupted barrier function and cell death in neighbouring wells. We highlight the ability of this cellular biosensor technology to reveal both the direct and gaseous toxicity mediated by sodium azide. The sensitivity and temporal dimension of ECIS technology was instrumental in these observations. These findings have substantial implications for the wide use of sodium azide in biological reagents, raising issues of their application in live-cell assays and with regard to the protection of the user. This research also has wider relevance highlighting the sensitivity of brain endothelial cells to a known mitochondrial disruptor. It is logical to hypothesise that BBB endothelial dysfunction due to mitochondrial dys-regulation could have an important but underappreciated role in a range of neurological diseases.

  11. The role of cytoskeleton in the regulation of vascular endothelial barrier function.

    PubMed

    Bogatcheva, Natalia V; Verin, Alexander D

    2008-11-01

    The cytoskeleton is vital to the function of virtually all cell types in the organism as it is required for cell division, cell motility, endo- or exocytosis and the maintenance of cell shape. Endothelial cells, lining the inner surface of the blood vessels, exploit cytoskeletal elements to ensure the integrity of cell monolayer in quiescent endothelium, and to enable the disintegration of the formed barrier in response to various agonists. Vascular permeability is defined by the combination of transcellular and paracellular pathways, with the latter being a major contributor to the inflammation-induced barrier dysfunction. This review will analyze the cytoskeletal elements, which reorganization affects endothelial permeability, and emphasize signaling mechanisms with barrier-protective or barrier-disruptive potential.

  12. Short term effects of gamma radiation on endothelial barrier function: uncoupling of PECAM-1.

    PubMed

    Sharma, Preety; Templin, Thomas; Grabham, Peter

    2013-03-01

    A limiting factor in the treatment of cancer with radiotherapy is the damage to surrounding normal tissue, particularly the vasculature. Vessel pathologies are a major feature of the side effects of radiotherapy and little is known about early events that could initiate subsequent diseases. We tested the hypothesis that gamma radiation has early damaging effects on the human endothelial barrier. Two models were used; Human Brain Microcapillary Endothelial Cells (HBMEC), and Human Umbilical Vein Endothelial Cells (HUVEC). Endpoints included Trans-Endothelial Electrical Resistance (TEER), barrier permeability to 10 kDa and 70 kDa tracer molecules, and the localization of F-actin, and junction proteins and the Platelet Endothelial Cell Adhesion Molecule (PECAM-1). Radiation induced a rapid and transient decrease in TEER at 3 h, with effects also seen at the radiotherapy doses. This dip in resistance correlated to the transient loss of PECAM-1 in discrete areas where cells often detached from the monolayer leaving gaps. Redistribution of PECAM-1 was also seen in 3-D human tissue models. By 6 h, the remaining cells had migrated to reseal the barrier, coincident with TEER returning to control levels. Resealed monolayers contained fewer cells per unit area and their barrier function was weakened as evidenced by an increased permeability over 24 h. This is the first demonstration of a transient and rapid effect of gamma radiation on human endothelial barriers that involves cell detachment and the loss of PECAM-1. Considering the association of cell adhesion molecules with vasculopathies, such an effect has the potential to be clinically relevant to the longer-term effects of radiotherapy. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Modulation of Rac1 Activity by ADMA/DDAH Regulates Pulmonary Endothelial Barrier Function

    PubMed Central

    Torondel, Belen; Zhao, Lan; Renné, Thomas; Leiper, James M.

    2009-01-01

    Endogenously produced nitric oxide synthase inhibitor, asymmetric methylarginine (ADMA) is associated with vascular dysfunction and endothelial leakage. We studied the role of ADMA, and the enzymes metabolizing it, dimethylarginine dimethylaminohydrolases (DDAH) in the regulation of endothelial barrier function in pulmonary macrovascular and microvascular cells in vitro and in lungs of genetically modified heterozygous DDAHI knockout mice in vivo. We show that ADMA increases pulmonary endothelial permeability in vitro and in in vivo and that this effect is mediated by nitric oxide (NO) acting via protein kinase G (PKG) and independent of reactive oxygen species formation. ADMA-induced remodeling of actin cytoskeleton and intercellular adherens junctions results from a decrease in PKG-mediated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and a subsequent down-regulation of Rac1 activity. The effects of ADMA on endothelial permeability, Rac1 activation and VASP phosphorylation are prevented by overexpression of active DDAHI and DDAHII, whereas inactive DDAH mutants have no effect. These findings demonstrate for the first time that ADMA metabolism critically determines pulmonary endothelial barrier function by modulating Rac1-mediated remodeling of the actin cytoskeleton and intercellular junctions. PMID:18923147

  14. Hydroxyalkenals and oxidized phospholipids modulation of endothelial cytoskeleton, focal adhesion and adherens junction proteins in regulating endothelial barrier function.

    PubMed

    Usatyuk, Peter V; Natarajan, Viswanathan

    2012-01-01

    Lipid peroxidation of polyunsaturated fatty acids generates bioactive aldehydes, which exhibit pro- and anti-inflammatory effects in cells and tissues. Accumulating evidence indicates that 4-hydroxynonenal (4-HNE), a major aldehyde derived from lipid peroxidation of n-6 polyunsaturated fatty acids trigger signals that modulates focal adhesion and adherens junction proteins thereby inducing endothelial barrier dysfunction. Similarly, oxidized phospholipids (Ox-PLs) generated by lipid peroxidation of phospholipids with polyunsaturated fatty acids have been implicated in atherogenesis, inflammation and gene expression. Interestingly, physiological concentration of Ox-PLs is anti-inflammatory and protect against endotoxin- and ventilator-associated acute lung injury. Thus, excess generation of bioactive hydroxyalkenals and Ox-PLs during oxidative stress contributes to pathophysiology of various diseases by modulating signaling pathways that regulate pro- and anti-inflammatory responses and barrier regulation. This review summarizes the role of 4-HNE and Ox-PLs affecting cell signaling pathways and endothelial barrier dysfunction through modulation of the activities of proteins/enzymes by Michael adducts formation, enhancing the level of protein tyrosine phosphorylation of the target proteins, and by reorganization of cytoskeletal, focal adhesion, and adherens junction proteins. A better understanding of molecular mechanisms of hydroxyalkenals- and Ox-PLs-mediated pro-and anti-inflammatory responses and barrier function may lead to development of novel therapies to ameliorate oxidative stress related cardio-pulmonary disorders. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Methamphetamine disrupts blood-brain barrier function by induction of oxidative stress in brain endothelial cells.

    PubMed

    Ramirez, Servio H; Potula, Raghava; Fan, Shongshan; Eidem, Tess; Papugani, Anil; Reichenbach, Nancy; Dykstra, Holly; Weksler, Babette B; Romero, Ignacio A; Couraud, Pierre O; Persidsky, Yuri

    2009-12-01

    Methamphetamine (METH), a potent stimulant with strong euphoric properties, has a high abuse liability and long-lasting neurotoxic effects. Recent studies in animal models have indicated that METH can induce impairment of the blood-brain barrier (BBB), thus suggesting that some of the neurotoxic effects resulting from METH abuse could be the outcome of barrier disruption. In this study, we provide evidence that METH alters BBB function through direct effects on endothelial cells and explore possible underlying mechanisms leading to endothelial injury. We report that METH increases BBB permeability in vivo, and exposure of primary human brain microvascular endothelial cells (BMVEC) to METH diminishes the tightness of BMVEC monolayers in a dose- and time-dependent manner by decreasing the expression of cell membrane-associated tight junction (TJ) proteins. These changes were accompanied by the enhanced production of reactive oxygen species, increased monocyte migration across METH-treated endothelial monolayers, and activation of myosin light chain kinase (MLCK) in BMVEC. Antioxidant treatment attenuated or completely reversed all tested aspects of METH-induced BBB dysfunction. Our data suggest that BBB injury is caused by METH-mediated oxidative stress, which activates MLCK and negatively affects the TJ complex. These observations provide a basis for antioxidant protection against brain endothelial injury caused by METH exposure.

  16. Inhibition of Murine Pulmonary Microvascular Endothelial Cell Apoptosis Promotes Recovery of Barrier Function under Septic Conditions

    PubMed Central

    Wang, Lefeng; Mehta, Sanjay; Brock, Michael

    2017-01-01

    Sepsis is characterized by injury of the pulmonary microvasculature and the pulmonary microvascular endothelial cells (PMVEC), leading to barrier dysfunction and acute respiratory distress syndrome (ARDS). Our recent work identified a strong correlation between PMVEC apoptosis and microvascular leak in septic mice in vivo, but the specific role of apoptosis in septic PMVEC barrier dysfunction remains unclear. Thus, we hypothesize that PMVEC apoptosis is likely required for PMVEC barrier dysfunction under septic conditions in vitro. Septic stimulation (mixture of tumour necrosis factor α, interleukin 1β, and interferon γ [cytomix]) of isolated murine PMVEC resulted in a significant loss of barrier function as early as 4 h after stimulation, which persisted until 24 h. PMVEC apoptosis, as reflected by caspase activation, DNA fragmentation, and loss of membrane polarity, was first apparent at 8 h after cytomix. Pretreatment of PMVEC with the pan-caspase inhibitor Q-VD significantly decreased septic PMVEC apoptosis and was associated with reestablishment of PMVEC barrier function at 16 and 24 h after stimulation but had no effect on septic PMVEC barrier dysfunction over the first 8 h. Collectively, our data suggest that early septic murine PMVEC barrier dysfunction driven by proinflammatory cytokines is not mediated through apoptosis, but PMVEC apoptosis contributes to late septic PMVEC barrier dysfunction. PMID:28250575

  17. Regulation of endothelial and epithelial barrier functions by peptide hormones of the adrenomedullin family

    PubMed Central

    García-Ponce, Alexander; Chánez Paredes, Sandra; Castro Ochoa, Karla Fabiola; Schnoor, Michael

    2016-01-01

    ABSTRACT The correct regulation of tissue barriers is of utmost importance for health. Barrier dysfunction accompanies inflammatory disorders and, if not controlled properly, can contribute to the development of chronic diseases. Tissue barriers are formed by monolayers of epithelial cells that separate organs from their environment, and endothelial cells that cover the vasculature, thus separating the blood stream from underlying tissues. Cells within the monolayers are connected by intercellular junctions that are linked by adaptor molecules to the cytoskeleton, and the regulation of these interactions is critical for the maintenance of tissue barriers. Many endogenous and exogenous molecules are known to regulate barrier functions in both ways. Proinflammatory cytokines weaken the barrier, whereas anti-inflammatory mediators stabilize barriers. Adrenomedullin (ADM) and intermedin (IMD) are endogenous peptide hormones of the same family that are produced and secreted by many cell types during physiologic and pathologic conditions. They activate certain G-protein-coupled receptor complexes to regulate many cellular processes such as cytokine production, actin dynamics and junction stability. In this review, we summarize current knowledge about the barrier-stabilizing effects of ADM and IMD in health and disease. PMID:28123925

  18. Tesmilifene modifies brain endothelial functions and opens the blood-brain/blood-glioma barrier.

    PubMed

    Walter, Fruzsina R; Veszelka, Szilvia; Pásztói, Mária; Péterfi, Zoltán A; Tóth, András; Rákhely, Gábor; Cervenak, László; Ábrahám, Csongor S; Deli, Mária A

    2015-09-01

    Tesmilifene, a tamoxifen analog with antihistamine action, has chemopotentiating properties in experimental and clinical cancer studies. In our previous works, tesmilifene increased the permeability of the blood-brain barrier (BBB) in animal and culture models. Our aim was to investigate the effects of tesmilifene on brain microvessel permeability in the rat RG2 glioma model and to reveal its mode of action in brain endothelial cells. Tesmilifene significantly increased fluorescein extravasation in the glioma. Short-term treatment with tesmilifene reduced the resistance and increased the permeability for marker molecules in a rat triple co-culture BBB model. Tesmilifene also affected the barrier integrity in brain endothelial cells co-cultured with RG2 glioblastoma cells. Tesmilifene inhibited the activity of P-glycoprotein and multidrug resistance-associated protein-1 efflux pumps and down-regulated the mRNA expression of tight junction proteins, efflux pumps, solute carriers, and metabolic enzymes important for BBB functions. Among the possible signaling pathways that regulate BBB permeability, tesmilifene activated the early nuclear translocation of NFκB. The MAPK/ERK and PI3K/Akt kinase pathways were also involved. We demonstrate for the first time that tesmilifene increases permeability marker molecule extravasation in glioma and inhibits efflux pump activity in brain endothelial cells, which may have therapeutic relevance. Tesmilifene, a chemopotentiator in experimental and clinical cancer studies increases vascular permeability in RG2 glioma in rats and permeability for marker molecules in a culture model of the blood-brain barrier. Tesmilifene inhibits the activity of efflux pumps and down-regulates the mRNA expression of tight junction proteins, transporters, and metabolic enzymes important for the blood-brain barrier functions, which may have therapeutic relevance.

  19. Regulation of endothelial barrier function by p120-catenin∙VE-cadherin interaction

    PubMed Central

    Garrett, Joshua P.; Lowery, Anthony M.; Adam, Alejandro P.; Kowalczyk, Andrew P.; Vincent, Peter A.

    2017-01-01

    Endothelial p120-catenin (p120) maintains the level of vascular endothelial cadherin (VE-Cad) by inhibiting VE-Cad endocytosis. Loss of p120 results in a decrease in VE-Cad levels, leading to the formation of monolayers with decreased barrier function (as assessed by transendothelial electrical resistance [TEER]), whereas overexpression of p120 increases VE-Cad levels and promotes a more restrictive monolayer. To test whether reduced endocytosis mediated by p120 is required for VE-Cad formation of a restrictive barrier, we restored VE-Cad levels using an endocytic-defective VE-Cad mutant. This endocytic-defective mutant was unable to rescue the loss of TEER associated with p120 or VE-Cad depletion. In contrast, the endocytic-defective mutant was able to prevent sprout formation in a fibrin bead assay, suggesting that p120•VE-Cad interaction regulates barrier function and angiogenic sprouting through different mechanisms. Further investigation found that depletion of p120 increases Src activity and that loss of p120 binding results in increased VE-Cad phosphorylation. In addition, expression of a Y658F–VE-Cad mutant or an endocytic-defective Y658F–VE-Cad double mutant were both able to rescue TEER independently of p120 binding. Our results show that in addition to regulating endocytosis, p120 also allows the phosphorylated form of VE-Cad to participate in the formation of a restrictive monolayer. PMID:27852896

  20. Connexins in endothelial barrier function - novel therapeutic targets countering vascular hyperpermeability.

    PubMed

    Soon, Allyson Shook Ching; Chua, Jia Wang; Becker, David Laurence

    2016-10-28

    Prolonged vascular hyperpermeability is a common feature of many diseases. Vascular hyperpermeability is typically associated with changes in the expression patterns of adherens and tight junction proteins. Here, we focus on the less-appreciated contribution of gap junction proteins (connexins) to basal vascular permeability and endothelial dysfunction. First, we assess the association of connexins with endothelial barrier integrity by introducing tools used in connexin biology and relating the findings to customary readouts in vascular biology. Second, we explore potential mechanistic ties between connexins and junction regulation. Third, we review the role of connexins in microvascular organisation and development, focusing on interactions of the endothelium with mural cells and tissue-specific perivascular cells. Last, we see how connexins contribute to the interactions between the endothelium and components of the immune system, by using neutrophils as an example. Mounting evidence of crosstalk between connexins and other junction proteins suggests that we rethink the way in which different junction components contribute to endothelial barrier function. Given the multiple points of connexin-mediated communication arising from the endothelium, there is great potential for synergism between connexin-targeted inhibitors and existing immune-targeted therapeutics. As more drugs targeting connexins progress through clinical trials, it is hoped that some might prove effective at countering vascular hyperpermeability.

  1. Regulation of endothelial barrier function by p120-catenin∙VE-cadherin interaction.

    PubMed

    Garrett, Joshua P; Lowery, Anthony M; Adam, Alejandro P; Kowalczyk, Andrew P; Vincent, Peter A

    2017-01-01

    Endothelial p120-catenin (p120) maintains the level of vascular endothelial cadherin (VE-Cad) by inhibiting VE-Cad endocytosis. Loss of p120 results in a decrease in VE-Cad levels, leading to the formation of monolayers with decreased barrier function (as assessed by transendothelial electrical resistance [TEER]), whereas overexpression of p120 increases VE-Cad levels and promotes a more restrictive monolayer. To test whether reduced endocytosis mediated by p120 is required for VE-Cad formation of a restrictive barrier, we restored VE-Cad levels using an endocytic-defective VE-Cad mutant. This endocytic-defective mutant was unable to rescue the loss of TEER associated with p120 or VE-Cad depletion. In contrast, the endocytic-defective mutant was able to prevent sprout formation in a fibrin bead assay, suggesting that p120•VE-Cad interaction regulates barrier function and angiogenic sprouting through different mechanisms. Further investigation found that depletion of p120 increases Src activity and that loss of p120 binding results in increased VE-Cad phosphorylation. In addition, expression of a Y658F-VE-Cad mutant or an endocytic-defective Y658F-VE-Cad double mutant were both able to rescue TEER independently of p120 binding. Our results show that in addition to regulating endocytosis, p120 also allows the phosphorylated form of VE-Cad to participate in the formation of a restrictive monolayer. © 2017 Garrett et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  2. MicroRNAs regulate tight junction proteins and modulate epithelial/endothelial barrier functions.

    PubMed

    Cichon, Christoph; Sabharwal, Harshana; Rüter, Christian; Schmidt, M Alexander

    2014-01-01

    Tightly controlled epithelial and endothelial barriers are a prerequisite for life as these barriers separate multicellular organisms from their environment and serve as first lines of defense. Barriers between neighboring epithelial cells are formed by multiple intercellular junctions including the 'apical junctional complex-AJC' with tight junctions (TJ), adherens junctions (AJ), and desmosomes. TJ consist of tetraspan transmembrane proteins like occludin, various claudins that directly control paracellular permeability, and the 'Junctional Adhesion Molecules' (JAMs). For establishing tight barriers TJ are essential but at the same time have to allow also selective permeability. For this, TJ need to be tightly regulated and controlled. This is organized by a variety of adaptor molecules, i.e., protein kinases, phosphatases and GTPases, which in turn are regulated and fine-tuned involving microRNAs (miRNAs). In this review we summarize available data on the role and targeting of miRNAs in the maintenance of epithelial and/or endothelial barriers.

  3. Regulation of vascular endothelial cell barrier function and cytoskeleton structure by protein phosphatases of the PPP family.

    PubMed

    Csortos, Csilla; Kolosova, Irina; Verin, Alexander D

    2007-10-01

    Reversible phosphorylation of cytoskeletal and cytoskeleton-associated proteins is a significant element of endothelial barrier function regulation. Therefore, understanding the mechanisms of phosphorylation/dephosphorylation of endothelial cell cytoskeletal proteins is vital to the treatment of severe lung disorders such as high permeability pulmonary edema. In vivo, there is a controlled balance between the activities of protein kinases and phosphatases. Due to various external or internal signals, this balance may be shifted. The actual balances at a given time alter the phosphorylation level of certain proteins with appropriate physiological consequences. The latest information about the structure and regulation of different types of Ser/Thr protein phosphatases participating in the regulation of endothelial cytoskeletal organization and barrier function will be reviewed here.

  4. Iloprost improves endothelial barrier function in LPS-induced lung injury

    PubMed Central

    Birukova, Anna A.; Wu, Tinghuai; Tian, Yufeng; Meliton, Angelo; Sarich, Nicolene; Tian, Xinyong; Leff, Alan; Birukov, Konstantin G.

    2013-01-01

    RATIONALE Protective effects of prostacyclin and its stable analog Iloprost are mediated by elevation of intracellular cAMP leading to enhancement of peripheral actin cytoskeleton and cell-cell adhesive structures. This study tested hypothesis that iloprost may exhibit protective effects against lung injury and endothelial barrier dysfunction induced by bacterial wall lypopolysacharide (LPS). METHODS Endothelial barrier dysfunction was assessed by measurements of transendothelial permeability, morphologically, and analysis of LPS-activated inflammatory signaling. In vivo, C57BL/6J mice were challenged with LPS with or without iloprost or 8-bromoadenosine-3′,5′-cyclic monophosphate (Br-cAMP) treatment. Lung injury was monitored by measurements of bronchoalveolar lavage protein content, cell count, and Evans blue extravasation. RESULTS Iloprost and Br-cAMP attenuated disruption of endothelial monolayer and suppressed activation of p38 mitogen activated protein (MAP) kinase, NFκB pathway, Rho signaling, ICAM1 expression, and neutrophil migration after LPS challenge. In vivo, iloprost was effective against LPS-induced protein and neutrophil accumulation in bronchoalveolar lavage fluid and reduced myeloperoxidase activation, ICAM-1 expression, and Evans blue extravasation in the lungs. Inhibition of Rac activity abolished barrier protective and anti-inflammatory effects of iloprost and Br-cAMP. CONCLUSION Iloprost-induced elevation of intracellular cAMP triggers Rac signaling, which attenuates LPS-induced NFκB and p38 MAPK inflammatory pathways and Rho-dependent mechanism of endothelial permeability. PMID:22790920

  5. The Mouse Blood-Brain Barrier Transcriptome: A New Resource for Understanding the Development and Function of Brain Endothelial Cells

    PubMed Central

    Daneman, Richard; Zhou, Lu; Agalliu, Dritan; Cahoy, John D.; Kaushal, Amit; Barres, Ben A.

    2010-01-01

    The blood-brain barrier (BBB) maintains brain homeostasis and limits the entry of toxins and pathogens into the brain. Despite its importance, little is known about the molecular mechanisms regulating the development and function of this crucial barrier. In this study we have developed methods to highly purify and gene profile endothelial cells from different tissues, and by comparing the transcriptional profile of brain endothelial cells with those purified from the liver and lung, we have generated a comprehensive resource of transcripts that are enriched in the BBB forming endothelial cells of the brain. Through this comparison we have identified novel tight junction proteins, transporters, metabolic enzymes, signaling components, and unknown transcripts whose expression is enriched in central nervous system (CNS) endothelial cells. This analysis has identified that RXRalpha signaling cascade is specifically enriched at the BBB, implicating this pathway in regulating this vital barrier. This dataset provides a resource for understanding CNS endothelial cells and their interaction with neural and hematogenous cells. PMID:21060791

  6. Electric cell-substrate impedance sensing for the quantification of endothelial proliferation, barrier function, and motility.

    PubMed

    Szulcek, Robert; Bogaard, Harm Jan; van Nieuw Amerongen, Geerten P

    2014-03-28

    Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. To this end, cells are grown in special culture chambers on top of opposing, circular gold electrodes. A constant small alternating current is applied between the electrodes and the potential across is measured. The insulating properties of the cell membrane create a resistance towards the electrical current flow resulting in an increased electrical potential between the electrodes. Measuring cellular impedance in this manner allows the automated study of cell attachment, growth, morphology, function, and motility. Although the ECIS measurement itself is straightforward and easy to learn, the underlying theory is complex and selection of the right settings and correct analysis and interpretation of the data is not self-evident. Yet, a clear protocol describing the individual steps from the experimental design to preparation, realization, and analysis of the experiment is not available. In this article the basic measurement principle as well as possible applications, experimental considerations, advantages and limitations of the ECIS system are discussed. A guide is provided for the study of cell attachment, spreading and proliferation; quantification of cell behavior in a confluent layer, with regard to barrier function, cell motility, quality of cell-cell and cell-substrate adhesions; and quantification of wound healing and cellular responses to vasoactive stimuli. Representative results are discussed based on human microvascular (MVEC) and human umbilical vein endothelial cells (HUVEC), but are applicable to all adherent growing cells.

  7. Electric Cell-substrate Impedance Sensing for the Quantification of Endothelial Proliferation, Barrier Function, and Motility

    PubMed Central

    Szulcek, Robert; Bogaard, Harm Jan; van Nieuw Amerongen, Geerten P.

    2014-01-01

    Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. To this end, cells are grown in special culture chambers on top of opposing, circular gold electrodes. A constant small alternating current is applied between the electrodes and the potential across is measured. The insulating properties of the cell membrane create a resistance towards the electrical current flow resulting in an increased electrical potential between the electrodes. Measuring cellular impedance in this manner allows the automated study of cell attachment, growth, morphology, function, and motility. Although the ECIS measurement itself is straightforward and easy to learn, the underlying theory is complex and selection of the right settings and correct analysis and interpretation of the data is not self-evident. Yet, a clear protocol describing the individual steps from the experimental design to preparation, realization, and analysis of the experiment is not available. In this article the basic measurement principle as well as possible applications, experimental considerations, advantages and limitations of the ECIS system are discussed. A guide is provided for the study of cell attachment, spreading and proliferation; quantification of cell behavior in a confluent layer, with regard to barrier function, cell motility, quality of cell-cell and cell-substrate adhesions; and quantification of wound healing and cellular responses to vasoactive stimuli. Representative results are discussed based on human microvascular (MVEC) and human umbilical vein endothelial cells (HUVEC), but are applicable to all adherent growing cells. PMID:24747269

  8. MicroRNAs regulate tight junction proteins and modulate epithelial/endothelial barrier functions

    PubMed Central

    Cichon, Christoph; Sabharwal, Harshana; Rüter, Christian; Schmidt, M Alexander

    2014-01-01

    Tightly controlled epithelial and endothelial barriers are a prerequisite for life as these barriers separate multicellular organisms from their environment and serve as first lines of defense. Barriers between neighboring epithelial cells are formed by multiple intercellular junctions including the ‘apical junctional complex—AJC’ with tight junctions (TJ), adherens junctions (AJ), and desmosomes. TJ consist of tetraspan transmembrane proteins like occludin, various claudins that directly control paracellular permeability, and the ‘Junctional Adhesion Molecules’ (JAMs). For establishing tight barriers TJ are essential but at the same time have to allow also selective permeability. For this, TJ need to be tightly regulated and controlled. This is organized by a variety of adaptor molecules, i.e., protein kinases, phosphatases and GTPases, which in turn are regulated and fine-tuned involving microRNAs (miRNAs). In this review we summarize available data on the role and targeting of miRNAs in the maintenance of epithelial and/or endothelial barriers. PMID:25610754

  9. Iloprost improves endothelial barrier function in lipopolysaccharide-induced lung injury.

    PubMed

    Birukova, Anna A; Wu, Tinghuai; Tian, Yufeng; Meliton, Angelo; Sarich, Nicolene; Tian, Xinyong; Leff, Alan; Birukov, Konstantin G

    2013-01-01

    The protective effects of prostacyclin and its stable analogue iloprost are mediated by elevation of intracellular cyclic AMP (cAMP) leading to enhancement of the peripheral actin cytoskeleton and cell-cell adhesive structures. This study tested the hypothesis that iloprost may exhibit protective effects against lung injury and endothelial barrier dysfunction induced by bacterial wall lipopolysaccharide (LPS). Endothelial barrier dysfunction was assessed by measurements of transendothelial permeability, morphologically and by analysis of LPS-activated inflammatory signalling. In vivo, C57BL/6J mice were challenged with LPS with or without iloprost or 8-bromoadenosine-3',5'-cyclic monophosphate (Br-cAMP) treatment. Lung injury was monitored by measurements of bronchoalveolar lavage protein content, cell count and Evans blue extravasation. Iloprost and Br-cAMP attenuated the disruption of the endothelial monolayer, and suppressed the activation of p38 mitogen-activated protein kinase (MAPK), the nuclear factor (NF)-κB pathway, Rho signalling, intercellular adhesion molecular (ICAM)-1 expression and neutrophil migration after LPS challenge. In vivo, iloprost was effective against LPS-induced protein and neutrophil accumulation in bronchoalveolar lavage fluid, and reduced myeloperoxidase activation, ICAM-1 expression and Evans blue extravasation in the lungs. Inhibition of Rac activity abolished the barrier-protective and anti-inflammatory effects of iloprost and Br-cAMP. Iloprost-induced elevation of intracellular cAMP triggers Rac signalling, which attenuates LPS-induced NF-κB and p38 MAPK inflammatory pathways and the Rho-dependent mechanism of endothelial permeability.

  10. Heat stress-induced disruption of endothelial barrier function is via PAR1 signaling and suppressed by Xuebijing injection.

    PubMed

    Xu, Qiulin; Liu, Jingxian; Wang, Zhenglian; Guo, Xiaohua; Zhou, Gengbiao; Liu, Yanan; Huang, Qiaobing; Su, Lei

    2015-01-01

    Increased vascular permeability leading to acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is central to the pathogenesis of heatstroke. Protease-activated receptor 1 (PAR1), the receptor for thrombin, plays a key role in disruption of endothelial barrier function in response to extracellular stimuli. However, the role of PAR1 in heat stress-induced endothelial hyper-permeability is unknown. In this study, we measured PAR1 protein expression in heat-stressed human umbilical venous endothelial cells (HUVECs), investigated the influences of PAR1 on endothelial permeability, F-actin rearrangement, and moesin phosphorylation by inhibiting PAR1 with its siRNA, neutralizing antibody (anti-PAR1), specific inhibitor(RWJ56110), and Xuebijing injection (XBJ), a traditional Chinese medicine used for sepsis treatment, and evaluated the role of PAR1 in heatstroke-related ALI/ARDS in mice by suppressing PAR1 with RWJ56110, anti-PAR1and XBJ. We found that heat stress induced PAR1 protein expression 2h after heat stress in endothelial cells, caused the release of endothelial matrix metalloprotease 1, an activator of PAR1, after 60 or 120 min of heat stimulation, as well as promoted endothelial hyper-permeability and F-actin rearrangement, which were inhibited by suppressing PAR1 with RWJ56110, anti-PAR1 and siRNA. PAR1 mediated moesin phosphorylation, which caused F-actin rearrangement and disruption of endothelial barrier function. To corroborate findings from in vitro experiments, we found that RWJ56110 and the anti-PAR1 significantly decreased lung edema, pulmonary microvascular permeability, protein exudation, and leukocytes infiltrations in heatstroke mice. Additionally, XBJ was found to suppress PAR1-moesin signal pathway and confer protective effects on maintaining endothelial barrier function both in vitro and in vivo heat-stressed model, similar to those observed above with the inhibition of PAR1. These results suggest that PAR1 is a potential

  11. Impedance analysis of GPCR-mediated changes in endothelial barrier function: overview, and fundamental considerations for stable and reproducible measurements

    PubMed Central

    Stolwijk, Judith A.; Matrougui, Khalid; Renken, Christian W.; Trebak, Mohamed

    2014-01-01

    The past 20 years have seen significant growth in using impedance-based assays to understand the molecular underpinning of endothelial and epithelial barrier function in response to physiological agonists, pharmacological and toxicological compounds. Most studies on barrier function use G protein coupled receptor (GPCR) agonists which couple to fast and transient changes in barrier properties. The power of impedance based techniques such as Electric Cell-Substrate Impedance Sensing (ECIS) reside in its ability to detect minute changes in cell layer integrity label-free and in real-time ranging from seconds to days. We provide a comprehensive overview of the biophysical principles, applications and recent developments in impedance-based methodologies. Despite extensive application of impedance analysis in endothelial barrier research little attention has been paid to data analysis and critical experimental variables, which are both essential for signal stability and reproducibility. We describe the rationale behind common ECIS data presentation and interpretation and illustrate practical guidelines to improve signal intensity by adapting technical parameters such as electrode layout, monitoring frequency or parameter (resistance versus impedance magnitude). Moreover, we discuss the impact of experimental parameters, including cell source, liquid handling and agonist preparation on signal intensity and kinetics. Our discussions are supported by experimental data obtained from human microvascular endothelial cells challenged with three GPCR agonists, thrombin, histamine and Sphingosine-1-Phosphate. PMID:25537398

  12. Impedance analysis of GPCR-mediated changes in endothelial barrier function: overview and fundamental considerations for stable and reproducible measurements.

    PubMed

    Stolwijk, Judith A; Matrougui, Khalid; Renken, Christian W; Trebak, Mohamed

    2015-10-01

    The past 20 years has seen significant growth in using impedance-based assays to understand the molecular underpinning of endothelial and epithelial barrier function in response to physiological agonists and pharmacological and toxicological compounds. Most studies on barrier function use G protein-coupled receptor (GPCR) agonists which couple to fast and transient changes in barrier properties. The power of impedance-based techniques such as electric cell-substrate impedance sensing (ECIS) resides in its ability to detect minute changes in cell layer integrity label-free and in real-time ranging from seconds to days. We provide a comprehensive overview of the biophysical principles, applications, and recent developments in impedance-based methodologies. Despite extensive application of impedance analysis in endothelial barrier research, little attention has been paid to data analysis and critical experimental variables, which are both essential for signal stability and reproducibility. We describe the rationale behind common ECIS data presentation and interpretation and illustrate practical guidelines to improve signal intensity by adapting technical parameters such as electrode layout, monitoring frequency, or parameter (resistance versus impedance magnitude). Moreover, we discuss the impact of experimental parameters, including cell source, liquid handling, and agonist preparation on signal intensity and kinetics. Our discussions are supported by experimental data obtained from human microvascular endothelial cells challenged with three GPCR agonists, thrombin, histamine, and sphingosine-1-phosphate.

  13. Cyclosporin A induces hyperpermeability of the blood-brain barrier by inhibiting autocrine adrenomedullin-mediated up-regulation of endothelial barrier function.

    PubMed

    Dohgu, Shinya; Sumi, Noriko; Nishioku, Tsuyoshi; Takata, Fuyuko; Watanabe, Takuya; Naito, Mikihiko; Shuto, Hideki; Yamauchi, Atsushi; Kataoka, Yasufumi

    2010-10-10

    Cyclosporin A, a potent immunosuppressant, can often produce neurotoxicity in patients, although its penetration into the brain is restricted by the blood-brain barrier (BBB). Brain pericytes and astrocytes, which are periendothelial accessory structures of the BBB, can be involved in cyclosporin A-induced BBB disruption. However, the mechanism by which cyclosporin A causes BBB dysfunction remains unknown. Here, we show that in rodent brain endothelial cells, cyclosporin A decreased transendothelial electrical resistance (TEER) by inhibiting intracellular signal transduction downstream of adrenomedullin, an autocrine regulator of BBB function. Cyclosporin A stimulated adrenomedullin release from brain endothelial cells, but did not affect binding of adrenomedullin to its receptors. This cyclosporin A-induced decrease in TEER was attenuated by exogenous addition of adrenomedullin. Cyclosporin A dose-dependently decreased the total cAMP concentration in brain endothelial cells. A combination of cyclosporin A (1microM) with an adenylyl cyclase inhibitor, 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (SQ22536; 10microM), or a protein kinase A (PKA) inhibitor, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H89; 1microM), markedly increased sodium fluorescein permeability in brain endothelial cells, whereas each drug alone had no effect. Thus, these data suggest that cyclosporin A inhibits the adenylyl cyclase/cyclic AMP/PKA signaling pathway activated by adrenomedullin, leading to impairment of brain endothelial barrier function. Copyright 2010. Published by Elsevier B.V.

  14. Estrogen protects renal endothelial barrier function from ischemia-reperfusion in vitro and in vivo

    PubMed Central

    Fujiyoshi, Tetsuhiro; Komers, Radko; Herson, Paco S.; Anderson, Sharon

    2012-01-01

    Emerging evidence suggests that renal endothelial function may be altered in ischemia-reperfusion injury. Acute kidney injury is sexually dimorphic, and estrogen protects renal tubular function after experimental ischemic injury. This study tested the hypothesis that during ischemia-reperfusion, estrogen alters glomerular endothelial function to prevent hyperpermeability. Glomerular endothelial cells were exposed to 8-h oxygen-glucose deprivation (OGD) followed by 4- and 8-h reoxygenation-glucose repletion. After 4-h reoxygenation-glucose repletion, transendothelial permeability to Ficoll-70 was reduced, and transendothelial resistance increased, by 17β-estradiol vs. vehicle treatment during OGD (OGD-vehicle: 91.0 ± 11.8%, OGD-estrogen: 102.6 ± 10.8%, P < 0.05). This effect was reversed by coadministration of G protein-coupled receptor 30 (GPR30) antagonist G15 with 17β-estradiol (OGD-estrogen-G15: 89.5 ± 6.9, P < 0.05 compared with 17β-estradiol). To provide preliminary confirmation of this result in vivo, Ficoll-70 was administered to mice 24 h after cardiac arrest and cardiopulmonary resuscitation (CA/CPR). Blood urea nitrogen (BUN) and serum creatinine (SCr) in these mice were elevated within 12 h following CA/CPR and reduced at 24 h by pretreatment with 17β-estradiol (BUN/SCr 17β-estradiol: 34 ± 19/0.2 ± 0.1 vehicle: 92 ± 49/0.5 ± 0.3, n = 8–12, P < 0.05). Glomerular sieving of Ficoll 70 was increased by CA/CPR within 2 h of injury and 17β-estradiol treatment (θ; 17β-estradiol: 0.74 ± 0.26 vs. vehicle: 1.05 ± 0.53, n = 14–15, P < 0.05). These results suggest that estrogen reduces postischemic glomerular endothelial hyperpermeability at least in part through GPR30 and that estrogen may regulate post CA/CPR glomerular permeability in a similar fashion in vivo. PMID:22622457

  15. Pitfalls in assessing microvascular endothelial barrier function: impedance-based devices versus the classic macromolecular tracer assay

    PubMed Central

    Bischoff, Iris; Hornburger, Michael C.; Mayer, Bettina A.; Beyerle, Andrea; Wegener, Joachim; Fürst, Robert

    2016-01-01

    The most frequently used parameters to describe the barrier properties of endothelial cells (ECs) in vitro are (i) the macromolecular permeability, indicating the flux of a macromolecular tracer across the endothelium, and (ii) electrical impedance of ECs grown on gold-film electrodes reporting on the cell layer’s tightness for ion flow. Due to the experimental differences between these approaches, inconsistent observations have been described. Here, we present the first direct comparison of these assays applied to one single cell type (human microvascular ECs) under the same experimental conditions. The impact of different pharmacological tools (histamine, forskolin, Y-27632, blebbistatin, TRAP) on endothelial barrier function was analyzed by Transwell® tracer assays and two commercial impedance devices (xCELLigence®, ECIS®). The two impedance techniques provided very similar results for all compounds, whereas macromolecular permeability readings were found to be partly inconsistent with impedance. Possible reasons for these discrepancies are discussed. We conclude that the complementary combination of both approaches is highly recommended to overcome the restrictions of each assay. Since the nature of the growth support may contribute to the observed differences, structure-function relationships should be based on cells that are consistently grown on either permeable or impermeable growth supports in all experiments. PMID:27025965

  16. Phospholipase Cε Modulates Rap1 Activity and the Endothelial Barrier

    PubMed Central

    DiStefano, Peter V.; Smrcka, Alan V.; Glading, Angela J.

    2016-01-01

    The phosphoinositide-specific phospholipase C, PLCε, is a unique signaling protein with known roles in regulating cardiac myocyte growth, astrocyte inflammatory signaling, and tumor formation. PLCε is also expressed in endothelial cells, however its role in endothelial regulation is not fully established. We show that endothelial cells of multiple origins, including human pulmonary artery (HPAEC), human umbilical vein (HUVEC), and immortalized brain microvascular (hCMEC/D3) endothelial cells, express PLCε. Knockdown of PLCε in arterial endothelial monolayers decreased the effectiveness of the endothelial barrier. Concomitantly, RhoA activity and stress fiber formation were increased. PLCε-deficient arterial endothelial cells also exhibited decreased Rap1-GTP levels, which could be restored by activation of the Rap1 GEF, Epac, to rescue the increase in monolayer leak. Reintroduction of PLCε rescued monolayer leak with both the CDC25 GEF domain and the lipase domain of PLCε required to fully activate Rap1 and to rescue endothelial barrier function. Finally, we demonstrate that the barrier promoting effects PLCε are dependent on Rap1 signaling through the Rap1 effector, KRIT1, which we have previously shown is vital for maintaining endothelial barrier stability. Thus we have described a novel role for PLCε PIP2 hydrolytic and Rap GEF activities in arterial endothelial cells, where PLCε-dependent activation of Rap1/KRIT1 signaling promotes endothelial barrier stability. PMID:27612188

  17. Phospholipase Cε Modulates Rap1 Activity and the Endothelial Barrier.

    PubMed

    DiStefano, Peter V; Smrcka, Alan V; Glading, Angela J

    2016-01-01

    The phosphoinositide-specific phospholipase C, PLCε, is a unique signaling protein with known roles in regulating cardiac myocyte growth, astrocyte inflammatory signaling, and tumor formation. PLCε is also expressed in endothelial cells, however its role in endothelial regulation is not fully established. We show that endothelial cells of multiple origins, including human pulmonary artery (HPAEC), human umbilical vein (HUVEC), and immortalized brain microvascular (hCMEC/D3) endothelial cells, express PLCε. Knockdown of PLCε in arterial endothelial monolayers decreased the effectiveness of the endothelial barrier. Concomitantly, RhoA activity and stress fiber formation were increased. PLCε-deficient arterial endothelial cells also exhibited decreased Rap1-GTP levels, which could be restored by activation of the Rap1 GEF, Epac, to rescue the increase in monolayer leak. Reintroduction of PLCε rescued monolayer leak with both the CDC25 GEF domain and the lipase domain of PLCε required to fully activate Rap1 and to rescue endothelial barrier function. Finally, we demonstrate that the barrier promoting effects PLCε are dependent on Rap1 signaling through the Rap1 effector, KRIT1, which we have previously shown is vital for maintaining endothelial barrier stability. Thus we have described a novel role for PLCε PIP2 hydrolytic and Rap GEF activities in arterial endothelial cells, where PLCε-dependent activation of Rap1/KRIT1 signaling promotes endothelial barrier stability.

  18. TGF-β Is Required for Vascular Barrier Function, Endothelial Survival and Homeostasis of the Adult Microvasculature

    PubMed Central

    Maharaj, Arindel S. R.; Sekiyama, Eiichi; Maldonado, Angel E.; D'Amore, Patricia A.

    2009-01-01

    Pericyte-endothelial cell (EC) interactions are critical to both vascular development and vessel stability. We have previously shown that TGF-β signaling between EC and mural cells participates in vessel stabilization in vitro. We therefore investigated the role of TGF-β signaling in maintaining microvessel structure and function in the adult mouse retinal microvasculature. TGF-β signaling was inhibited by systemic expression of soluble endoglin (sEng) and inhibition was demonstrated by reduced phospho-smad2 in the adult retina. Blockade of TGF-β signaling led to increased vascular and neural cell apoptosis in the retina, which was associated with decreased retinal function, as measured by electroretinogram (ERG). Perfusion of the inner retinal vasculature was impaired and was accompanied by defective autoregulation and loss of capillary integrity. Fundus angiography and Evans blue permeability assay revealed a breakdown of the blood-retinal-barrier that was characterized by decreased association between the tight junction proteins zo-1 and occludin. Inhibition of TGF-β signaling in cocultures of EC and 10T1/2 cells corroborated the in vivo findings, with impaired EC barrier function, dissociation of EC from 10T1/2 cells, and endothelial cell death, supporting the role of EC-mesenchymal interactions in TGF-β signaling. These results implicate constitutive TGF-β signaling in maintaining the integrity and function of the adult microvasculature and shed light on the potential role of TGF-β signaling in vasoproliferative and vascular degenerative retinal diseases. PMID:19340291

  19. Synergism of MSC-secreted HGF and VEGF in stabilising endothelial barrier function upon lipopolysaccharide stimulation via the Rac1 pathway.

    PubMed

    Yang, Yi; Chen, Qi-Hong; Liu, Ai-Ran; Xu, Xiu-Ping; Han, Ji-Bin; Qiu, Hai-Bo

    2015-12-16

    Mesenchymal stem cells (MSCs) stabilise endothelial barrier function in acute lung injury via paracrine hepatocyte growth factor (HGF). Vascular endothelial growth factor (VEGF), which is secreted by MSCs, is another key regulator of endothelial permeability; however, its role in adjusting permeability remains controversial. In addition, whether an interaction occurs between HGF and VEGF, which are secreted by MSCs, is not completely understood. We introduced a co-cultured model of human pulmonary microvascular endothelial cells (HPMECs) and MSC conditioned medium (CM) collected from MSCs after 24 h of hypoxic culture. The presence of VEGF and HGF in the MSC-CM was neutralised by anti-VEGF and anti-HGF antibodies, respectively. To determine the roles and mechanisms of MSC-secreted HGF and VEGF, we employed recombinant humanised HGF and recombinant humanised VEGF to co-culture with HPMECs. Additionally, we employed the RhoA inhibitor C3 transferase and the Rac1 inhibitor NSC23766 to inhibit the activities of RhoA and Rac1 in HPMECs treated with MSC-CM or VEGF/HGF with the same dosage as in the MSC-CM. Then, endothelial paracellular and transcellular permeability was detected. VE-cadherin, occludin and caveolin-1 protein expression in HPMECs was measured by western blot. Adherens junction proteins, including F-actin and VE-cadherin, were detected by immunofluorescence. MSC-CM treatment significantly decreased lipopolysaccharide-induced endothelial paracellular and transcellular permeability, which was significantly inhibited by pretreatment with HGF antibody or with both VEGF and HGF antibodies. Furthermore, MSC-CM treatment increased the expression of the endothelial intercellular adherence junction proteins VE-cadherin and occludin and decreased the expression of caveolin-1 protein. MSC-CM treatment also decreased endothelial apoptosis and induced endothelial cell proliferation; however, the effects of MSC-CM treatment were inhibited by pretreatment with HGF

  20. The barrier within: endothelial transport of hormones.

    PubMed

    Kolka, Cathryn M; Bergman, Richard N

    2012-08-01

    Hormones are involved in a plethora of processes including development and growth, metabolism, mood, and immune responses. These essential functions are dependent on the ability of the hormone to access its target tissue. In the case of endocrine hormones that are transported through the blood, this often means that the endothelium must be crossed. Many studies have shown that the concentrations of hormones and nutrients in blood can be very different from those surrounding the cells on the tissue side of the blood vessel endothelium, suggesting that transport across this barrier can be rate limiting for hormone action. This transport can be regulated by altering the surface area of the blood vessel available for diffusion through to the underlying tissue or by the permeability of the endothelium. Many hormones are known to directly or indirectly affect the endothelial barrier, thus affecting their own distribution to their target tissues. Dysfunction of the endothelial barrier is found in many diseases, particularly those associated with the metabolic syndrome. The interrelatedness of hormones may help to explain why the cluster of diseases in the metabolic syndrome occur together so frequently and suggests that treating the endothelium may ameliorate defects in more than one disease. Here, we review the structure and function of the endothelium, its contribution to the function of hormones, and its involvement in disease.

  1. The Barrier Within: Endothelial Transport of Hormones

    PubMed Central

    Kolka, Cathryn M.; Bergman, Richard N.

    2015-01-01

    Hormones are involved in a plethora of processes including development and growth, metabolism, mood, and immune responses. These essential functions are dependent on the ability of the hormone to access its target tissue. In the case of endocrine hormones that are transported through the blood, this often means that the endothelium must be crossed. Many studies have shown that the concentrations of hormones and nutrients in blood can be very different from those surrounding the cells on the tissue side of the blood vessel endothelium, suggesting that transport across this barrier can be rate limiting for hormone action. This transport can be regulated by altering the surface area of the blood vessel available for diffusion through to the underlying tissue or by the permeability of the endothelium. Many hormones are known to directly or indirectly affect the endothelial barrier, thus affecting their own distribution to their target tissues. Dysfunction of the endothelial barrier is found in many diseases, particularly those associated with the metabolic syndrome. The interrelatedness of hormones may help to explain why the cluster of diseases in the metabolic syndrome occur together so frequently and suggests that treating the endothelium may ameliorate defects in more than one disease. Here, we review the structure and function of the endothelium, its contribution to the function of hormones, and its involvement in disease. PMID:22875454

  2. TNF-induced endothelial barrier disruption: beyond actin and Rho.

    PubMed

    Marcos-Ramiro, B; García-Weber, D; Millán, J

    2014-12-01

    The decrease of endothelial barrier function is central to the long-term inflammatory response. A pathological alteration of the ability of endothelial cells to modulate the passage of cells and solutes across the vessel underlies the development of inflammatory diseases such as atherosclerosis and multiple sclerosis. The inflammatory cytokine tumour necrosis factor (TNF) mediates changes in the barrier properties of the endothelium. TNF activates different Rho GTPases, increases filamentous actin and remodels endothelial cell morphology. However, inhibition of actin-mediated remodelling is insufficient to prevent endothelial barrier disruption in response to TNF, suggesting that additional molecular mechanisms are involved. Here we discuss, first, the pivotal role of Rac-mediated generation of reactive oxygen species (ROS) to regulate the integrity of endothelial cell-cell junctions and, second, the ability of endothelial adhesion receptors such as ICAM-1, VCAM-1 and PECAM-1, involved in leukocyte transendothelial migration, to control endothelial permeability to small molecules, often through ROS generation. These adhesion receptors regulate endothelial barrier function in ways both dependent on and independent of their engagement by immune cells, and orchestrate the crosstalk between leukocyte transendothelial migration and endothelial permeability during inflammation.

  3. Impaired endothelial barrier function in apolipoprotein M–deficient mice is dependent on sphingosine-1-phosphate receptor 1

    PubMed Central

    Christensen, Pernille M.; Liu, Catherine H.; Swendeman, Steven L.; Obinata, Hideru; Qvortrup, Klaus; Nielsen, Lars B.; Hla, Timothy; Christoffersen, Christina

    2016-01-01

    Apolipoprotein M (ApoM) transports sphingosine-1-phosphate (S1P) in plasma, and ApoM-deficient mice (Apom−/−) have ∼50% reduced plasma S1P levels. There are 5 known S1P receptors, and S1P induces adherens junction formation between endothelial cells through the S1P1 receptor, which in turn suppresses vascular leak. Increased vascular permeability is a hallmark of inflammation. The purpose of this study was to explore the relationships between vascular leakage in ApoM deficiency and S1P1 function in normal physiology and in inflammation. Vascular permeability in the lungs was assessed by accumulation of dextran molecules (70 kDa) and was increased ∼40% in Apom−/− mice compared to WT (C57Bl6/j) mice. Reconstitution of plasma ApoM/S1P or treatment with an S1P1 receptor agonist (SEW2871) rapidly reversed the vascular leakage to a level similar to that in WT mice, suggesting that it is caused by decreased plasma levels of S1P and reduced S1P1 stimulation. In a carrageenan-induced model of inflammation, Apom−/− mice had increased vascular leakage compared with that in WT mice. Adenoviral overexpression of ApoM in Apom−/− mice decreased the vascular leakage compared to adenoviral overexpression of green fluorescent protein. The study suggests that vascular leakage of albumin-sized particles in ApoM deficiency is S1P- and S1P1-dependent and this dependency exacerbates the response to inflammatory stimuli.—Christensen, P. M., Liu, C. H., Swendeman, S. L., Obinata, H., Qvortrup, K., Nielsen, L B., Hla, T., Di Lorenzo, A., Christoffersen, C. Impaired endothelial barrier function in apolipoprotein M-deficient mice is dependent on sphingosine-1-phosphate receptor 1. PMID:26956418

  4. Impaired endothelial barrier function in apolipoprotein M-deficient mice is dependent on sphingosine-1-phosphate receptor 1.

    PubMed

    Christensen, Pernille M; Liu, Catherine H; Swendeman, Steven L; Obinata, Hideru; Qvortrup, Klaus; Nielsen, Lars B; Hla, Timothy; Di Lorenzo, Annarita; Christoffersen, Christina

    2016-06-01

    Apolipoprotein M (ApoM) transports sphingosine-1-phosphate (S1P) in plasma, and ApoM-deficient mice (Apom(-/-)) have ∼50% reduced plasma S1P levels. There are 5 known S1P receptors, and S1P induces adherens junction formation between endothelial cells through the S1P1 receptor, which in turn suppresses vascular leak. Increased vascular permeability is a hallmark of inflammation. The purpose of this study was to explore the relationships between vascular leakage in ApoM deficiency and S1P1 function in normal physiology and in inflammation. Vascular permeability in the lungs was assessed by accumulation of dextran molecules (70 kDa) and was increased ∼40% in Apom(-/-) mice compared to WT (C57Bl6/j) mice. Reconstitution of plasma ApoM/S1P or treatment with an S1P1 receptor agonist (SEW2871) rapidly reversed the vascular leakage to a level similar to that in WT mice, suggesting that it is caused by decreased plasma levels of S1P and reduced S1P1 stimulation. In a carrageenan-induced model of inflammation, Apom(-/-) mice had increased vascular leakage compared with that in WT mice. Adenoviral overexpression of ApoM in Apom(-/-) mice decreased the vascular leakage compared to adenoviral overexpression of green fluorescent protein. The study suggests that vascular leakage of albumin-sized particles in ApoM deficiency is S1P- and S1P1-dependent and this dependency exacerbates the response to inflammatory stimuli.-Christensen, P. M., Liu, C. H., Swendeman, S. L., Obinata, H., Qvortrup, K., Nielsen, L B., Hla, T., Di Lorenzo, A., Christoffersen, C. Impaired endothelial barrier function in apolipoprotein M-deficient mice is dependent on sphingosine-1-phosphate receptor 1. © FASEB.

  5. Lipid rafts regulate PCB153-induced disruption of occludin and brain endothelial barrier function through protein phosphatase 2A and matrix metalloproteinase-2.

    PubMed

    Eum, Sung Yong; Jaraki, Dima; András, Ibolya E; Toborek, Michal

    2015-09-15

    Occludin is an essential integral transmembrane protein regulating tight junction (TJ) integrity in brain endothelial cells. Phosphorylation of occludin is associated with its localization to TJ sites and incorporation into intact TJ assembly. The present study is focused on the role of lipid rafts in polychlorinated biphenyl (PCB)-induced disruption of occludin and endothelial barrier function. Exposure of human brain endothelial cells to 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) induced dephosphorylation of threonine residues of occludin and displacement of occludin from detergent-resistant membrane (DRM)/lipid raft fractions within 1h. Moreover, lipid rafts modulated the reduction of occludin level through activation of matrix metalloproteinase 2 (MMP-2) after 24h PCB153 treatment. Inhibition of protein phosphatase 2A (PP2A) activity by okadaic acid or fostriecin markedly protected against PCB153-induced displacement of occludin and increased permeability of endothelial cells. The implication of lipid rafts and PP2A signaling in these processes was further defined by co-immunoprecipitation of occludin with PP2A and caveolin-1, a marker protein of lipid rafts. Indeed, a significant MMP-2 activity was observed in lipid rafts and was increased by exposure to PCB153. The pretreatment of MMP-2 inhibitors protected against PCB153-induced loss of occludin and disruption of lipid raft structure prevented the increase of endothelial permeability. Overall, these results indicate that lipid raft-associated processes, such as PP2A and MMP-2 activation, participate in PCB153-induced disruption of occludin function in brain endothelial barrier. This study contributes to a better understanding of the mechanisms leading to brain endothelial barrier dysfunction in response to exposure to environmental pollutants, such as ortho-substituted PCBs.

  6. Cellular crosstalk between airway epithelial and endothelial cells regulates barrier functions during exposure to double‐stranded RNA

    PubMed Central

    Reale, Riccardo; Held, Marie; Loxham, Matthew; Millar, Timothy M.; Collins, Jane E.; Swindle, Emily J.; Morgan, Hywel; Davies, Donna E.

    2017-01-01

    Abstract Introduction The epithelial and endothelial barriers of the airway mucosa are critical for regulation of tissue homeostasis and protection against pathogens or other tissue damaging agents. In response to a viral infection, epithelial cells must signal to the endothelium to initiate immune cell recruitment. This is a highly temporal regulated process; however, the mechanisms of this cross‐talk are not fully understood. Methods In a close‐contact co‐culture model of human airway epithelial and endothelial cells, cellular crosstalk was analyzed using transepithelial electrical resistance (TER) measurements, immunofluorescence, electron microscopy, and ELISA. Viral infections were simulated by exposing airway epithelial cells apically to double‐stranded RNA (Poly(I:C)). Using a microfluidic culture system, the temporal release of mediators was analyzed in the co‐culture model. Results Within 4 h of challenge, double‐stranded RNA induced the release of TNF‐α by epithelial cells. This activated endothelial cells by triggering the release of the chemoattractant CX3CL1 (fractalkine) by 8 h post‐challenge and expression of adhesion molecules E‐selectin and ICAM‐1. These responses were significantly reduced by neutralising TNF‐α. Conclusion By facilitating kinetic profiling, the microfluidic co‐culture system has enabled identification of a key signaling mechanism between the epithelial and endothelial barriers. Better understanding of cell–cell cross‐talk and its regulatory mechanisms has the potential to identify new therapeutic strategies to control airway inflammation. PMID:28250924

  7. Src Family Kinases Modulate the Loss of Endothelial Barrier Function in Response to TNF-α: Crosstalk with p38 Signaling

    PubMed Central

    Lowery, Anthony M.; Martino, Nina; Alsaffar, Hiba; Vincent, Peter A.

    2016-01-01

    Activation of Src Family Kinase (SFK) signaling is required for the increase in endothelial permeability induced by a variety of cytokines and growth factors. However, we previously demonstrated that activation of endogenous SFKs by expression of dominant negative C-terminal Src Kinase (DN-Csk) is not sufficient to decrease endothelial adherens junction integrity. Basal SFK activity has been observed in normal venular endothelia and was not associated with increased basal permeability. The basal SFK activity however was found to contribute to increased sensitivity of the venular endothelium to inflammatory mediator-induced leakage. How SFK activation achieves this is still not well understood. Here, we show that SFK activation renders human dermal microvascular endothelial cells susceptible to low doses of TNF-α. Treatment of DN-Csk-expressing cells with 50 pg/ml TNF-α induced a loss of TEER as well as drastic changes in the actin cytoskeleton and focal adhesion proteins. This synergistic effect was independent of ROCK or NF-κB activity. TNF-α-induced p38 signaling was required for the synergistic effect on barrier function, and activation of the p38 MAPK alone was also able to induce changes in permeability only in monolayers with active SFKs. These results suggest that the activation of endogenous levels of SFK renders the endothelial barrier more susceptible to low, physiologic doses of TNF-α through activation of p38 which leads to a loss of endothelial tight junctions. PMID:27603666

  8. Lipid rafts regulate PCB153-induced disruption of occludin and brain endothelial barrier function through protein phosphatase 2A and matrix metalloproteinase-2

    SciTech Connect

    Eum, Sung Yong Jaraki, Dima; András, Ibolya E.; Toborek, Michal

    2015-09-15

    Occludin is an essential integral transmembrane protein regulating tight junction (TJ) integrity in brain endothelial cells. Phosphorylation of occludin is associated with its localization to TJ sites and incorporation into intact TJ assembly. The present study is focused on the role of lipid rafts in polychlorinated biphenyl (PCB)-induced disruption of occludin and endothelial barrier function. Exposure of human brain endothelial cells to 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB153) induced dephosphorylation of threonine residues of occludin and displacement of occludin from detergent-resistant membrane (DRM)/lipid raft fractions within 1 h. Moreover, lipid rafts modulated the reduction of occludin level through activation of matrix metalloproteinase 2 (MMP-2) after 24 h PCB153 treatment. Inhibition of protein phosphatase 2A (PP2A) activity by okadaic acid or fostriecin markedly protected against PCB153-induced displacement of occludin and increased permeability of endothelial cells. The implication of lipid rafts and PP2A signaling in these processes was further defined by co-immunoprecipitation of occludin with PP2A and caveolin-1, a marker protein of lipid rafts. Indeed, a significant MMP-2 activity was observed in lipid rafts and was increased by exposure to PCB153. The pretreatment of MMP-2 inhibitors protected against PCB153-induced loss of occludin and disruption of lipid raft structure prevented the increase of endothelial permeability. Overall, these results indicate that lipid raft-associated processes, such as PP2A and MMP-2 activation, participate in PCB153-induced disruption of occludin function in brain endothelial barrier. This study contributes to a better understanding of the mechanisms leading to brain endothelial barrier dysfunction in response to exposure to environmental pollutants, such as ortho-substituted PCBs. - Highlights: • PCB153 disturbed human brain endothelial barrier through disruption of occludin. • Lipid raft-associated PP

  9. The RNA-binding protein quaking maintains endothelial barrier function and affects VE-cadherin and β-catenin protein expression

    PubMed Central

    de Bruin, Ruben G.; van der Veer, Eric P.; Prins, Jurriën; Lee, Dae Hyun; Dane, Martijn J. C.; Zhang, Huayu; Roeten, Marko K.; Bijkerk, Roel; de Boer, Hetty C.; Rabelink, Ton J.; van Zonneveld, Anton Jan; van Gils, Janine M.

    2016-01-01

    Proper regulation of endothelial cell-cell contacts is essential for physiological functioning of the endothelium. Interendothelial junctions are actively involved in the control of vascular leakage, leukocyte diapedesis, and the initiation and progression of angiogenesis. We found that the RNA-binding protein quaking is highly expressed by endothelial cells, and that its expression was augmented by prolonged culture under laminar flow and the transcription factor KLF2 binding to the promoter. Moreover, we demonstrated that quaking directly binds to the mRNA of VE-cadherin and β-catenin and can induce mRNA translation mediated by the 3′UTR of these genes. Reduced quaking levels attenuated VE-cadherin and β-catenin expression and endothelial barrier function in vitro and resulted in increased bradykinin-induced vascular leakage in vivo. Taken together, we report that quaking is essential in maintaining endothelial barrier function. Our results provide novel insight into the importance of post-transcriptional regulation in controlling vascular integrity. PMID:26905650

  10. Contacting co-culture of human retinal microvascular endothelial cells alters barrier function of human embryonic stem cell derived retinal pigment epithelial cells.

    PubMed

    Skottman, H; Muranen, J; Lähdekorpi, H; Pajula, E; Mäkelä, K; Koivusalo, L; Koistinen, A; Uusitalo, H; Kaarniranta, K; Juuti-Uusitalo, K

    2017-10-01

    Here we evaluated the effects of human retinal microvascular endothelial cells (hREC) on mature human embryonic stem cell (hESC) derived retinal pigment epithelial (RPE) cells. The hESC-RPE cells (Regea08/017, Regea08/023 or Regea11/013) and hREC (ACBRI 181) were co-cultured on opposite sides of transparent membranes for up to six weeks. Thereafter barrier function, small molecule permeability, localization of RPE and endothelial cell marker proteins, cellular fine structure, and growth factor secretion of were evaluated. After co-culture, the RPE specific CRALBP and endothelial cell specific von Willebrand factor were appropriately localized. In addition, the general morphology, pigmentation, and fine structure of hESC-RPE cells were unaffected. Co-culture increased the barrier function of hESC-RPE cells, detected both with TEER measurements and cumulative permeability of FD4 - although the differences varied among the cell lines. Co-culturing significantly altered VEGF and PEDF secretion, but again the differences were cell line specific. The results of this study showed that co-culture with hREC affects hESC-RPE functionality. In addition, co-culture revealed drastic cell line specific differences, most notably in growth factor secretion. This model has the potential to be used as an in vitro outer blood-retinal barrier model for drug permeability testing. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Soluble complement receptor 1 preserves endothelial barrier function and microcirculation in postischemic pancreatitis in the rat.

    PubMed

    von Dobschuetz, E; Bleiziffer, O; Pahernik, S; Dellian, M; Hoffmann, T; Messmer, K

    2004-05-01

    Components of the activated complement cascade are considered to play a pivotal role in ischemia-reperfusion-induced organ injury. With the use of intravital epifluorescence microscopy, we investigated the effect of complement inhibition by the recombinant soluble complement receptor 1 (sCR1; TP10) on the effect of macromolecular microvascular permeability, functional capillary perfusion, and leukocyte endothelium interaction in postischemic pancreatitis. Anaesthetized Sprague-Dawley rats were subjected to 60 min of normothermic pancreatic ischemia induced by microclipping of the blood-supplying arteries of the organ. Rats who received sCR1 (15 mg/kg body wt iv; n = 7) during reperfusion showed a significant reduction of permeability (1.77 +/- 1.34 x 10(-8) cm/s; n = 7) of tetramethylrhodamine isothiocyanate-labeled albumin injected 90 min after the onset of reperfusion compared with vehicle-treated animals (6.95 +/- 1.56 x 10(-8) cm/s; n = 7). At 120 min after the onset of reperfusion, the length of red blood cell-perfused capillaries (functional capillary density) was significantly improved (from 279 +/- 15.7 to 330 +/- 3.7 cm(-1); n = 7) and the number of leukocytes adherent to postcapillary venules was significantly reduced (from 314 +/- 87 to 163 +/- 71 mm(-2); n = 7) by sCR1 compared with vehicle treatment. Complement inhibition by sCR1 effectively ameliorates pancreatic ischemia-reperfusion-induced microcirculatory disturbances and might be considered for treatment of postischemic pancreatitis.

  12. Insulin-Like Growth Factor (IGF)-I Modulates Endothelial Blood-Brain Barrier Function in Ischemic Middle-Aged Female Rats.

    PubMed

    Bake, Shameena; Okoreeh, Andre K; Alaniz, Robert C; Sohrabji, Farida

    2016-01-01

    In comparison with young females, middle-aged female rats sustain greater cerebral infarction and worse functional recovery after stroke. These poorer stroke outcomes in middle-aged females are associated with an age-related reduction in IGF-I levels. Poststroke IGF-I treatment decreases infarct volume in older females and lowers the expression of cytokines in the ischemic hemisphere. IGF-I also reduces transfer of Evans blue dye to the brain, suggesting that this peptide may also promote blood-brain barrier function. To test the hypothesis that IGF-I may act at the blood-brain barrier in ischemic stroke, 2 approaches were used. In the first approach, middle-aged female rats were subjected to middle cerebral artery occlusion and treated with IGF-I after reperfusion. Mononuclear cells from the ischemic hemisphere were stained for CD4 or triple-labeled for CD4/CD25/FoxP3 and subjected to flow analyses. Both cohorts of cells were significantly reduced in IGF-I-treated animals compared with those in vehicle controls. Reduced trafficking of immune cells to the ischemic site suggests that blood-brain barrier integrity is better maintained in IGF-I-treated animals. The second approach directly tested the effect of IGF-I on barrier function of aging endothelial cells. Accordingly, brain microvascular endothelial cells from middle-aged female rats were cultured ex vivo and subjected to ischemic conditions (oxygen-glucose deprivation). IGF-I treatment significantly reduced the transfer of fluorescently labeled BSA across the endothelial monolayer as well as cellular internalization of fluorescein isothiocyanate-BSA compared with those in vehicle-treated cultures, Collectively, these data support the hypothesis that IGF-I improves blood-brain barrier function in middle-aged females.

  13. Insulin-Like Growth Factor (IGF)-I Modulates Endothelial Blood-Brain Barrier Function in Ischemic Middle-Aged Female Rats

    PubMed Central

    Bake, Shameena; Okoreeh, Andre K.; Alaniz, Robert C.

    2016-01-01

    In comparison with young females, middle-aged female rats sustain greater cerebral infarction and worse functional recovery after stroke. These poorer stroke outcomes in middle-aged females are associated with an age-related reduction in IGF-I levels. Poststroke IGF-I treatment decreases infarct volume in older females and lowers the expression of cytokines in the ischemic hemisphere. IGF-I also reduces transfer of Evans blue dye to the brain, suggesting that this peptide may also promote blood-brain barrier function. To test the hypothesis that IGF-I may act at the blood-brain barrier in ischemic stroke, 2 approaches were used. In the first approach, middle-aged female rats were subjected to middle cerebral artery occlusion and treated with IGF-I after reperfusion. Mononuclear cells from the ischemic hemisphere were stained for CD4 or triple-labeled for CD4/CD25/FoxP3 and subjected to flow analyses. Both cohorts of cells were significantly reduced in IGF-I–treated animals compared with those in vehicle controls. Reduced trafficking of immune cells to the ischemic site suggests that blood-brain barrier integrity is better maintained in IGF-I–treated animals. The second approach directly tested the effect of IGF-I on barrier function of aging endothelial cells. Accordingly, brain microvascular endothelial cells from middle-aged female rats were cultured ex vivo and subjected to ischemic conditions (oxygen-glucose deprivation). IGF-I treatment significantly reduced the transfer of fluorescently labeled BSA across the endothelial monolayer as well as cellular internalization of fluorescein isothiocyanate–BSA compared with those in vehicle-treated cultures, Collectively, these data support the hypothesis that IGF-I improves blood-brain barrier function in middle-aged females. PMID:26556536

  14. Flow shear stress regulates endothelial barrier function and expression of angiogenic factors in a 3D microfluidic tumor vascular model

    PubMed Central

    Buchanan, Cara F; Verbridge, Scott S; Vlachos, Pavlos P; Rylander, Marissa Nichole

    2014-01-01

    Endothelial cells lining blood vessels are exposed to various hemodynamic forces associated with blood flow. These include fluid shear, the tangential force derived from the friction of blood flowing across the luminal cell surface, tensile stress due to deformation of the vessel wall by transvascular flow, and normal stress caused by the hydrodynamic pressure differential across the vessel wall. While it is well known that these fluid forces induce changes in endothelial morphology, cytoskeletal remodeling, and altered gene expression, the effect of flow on endothelial organization within the context of the tumor microenvironment is largely unknown. Using a previously established microfluidic tumor vascular model, the objective of this study was to investigate the effect of normal (4 dyn/cm2), low (1 dyn/cm2), and high (10 dyn/cm2) microvascular wall shear stress (WSS) on tumor-endothelial paracrine signaling associated with angiogenesis. It is hypothesized that high WSS will alter the endothelial phenotype such that vascular permeability and tumor-expressed angiogenic factors are reduced. Results demonstrate that endothelial permeability decreases as a function of increasing WSS, while co-culture with tumor cells increases permeability relative to mono-cultures. This response is likely due to shear stress-mediated endothelial cell alignment and tumor-VEGF-induced permeability. In addition, gene expression analysis revealed that high WSS (10 dyn/cm2) significantly down-regulates tumor-expressed MMP9, HIF1, VEGFA, ANG1, and ANG2, all of which are important factors implicated in tumor angiogenesis. This result was not observed in tumor mono-cultures or static conditioned media experiments, suggesting a flow-mediated paracrine signaling mechanism exists with surrounding tumor cells that elicits a change in expression of angiogenic factors. Findings from this work have significant implications regarding low blood velocities commonly seen in the tumor vasculature

  15. Metformin induces up-regulation of blood-brain barrier functions by activating AMP-activated protein kinase in rat brain microvascular endothelial cells.

    PubMed

    Takata, Fuyuko; Dohgu, Shinya; Matsumoto, Junichi; Machida, Takashi; Kaneshima, Shuji; Matsuo, Mai; Sakaguchi, Shinya; Takeshige, Yuki; Yamauchi, Atsushi; Kataoka, Yasufumi

    2013-04-19

    Blood-brain barrier (BBB) disruption occurs frequently in CNS diseases and injuries. Few drugs have been developed as therapeutic candidates for facilitating BBB functions. Here, we examined whether metformin up-regulates BBB functions using rat brain microvascular endothelial cells (RBECs). Metformin, concentration- and time-dependently increased transendothelial electrical resistance of RBEC monolayers, and decreased RBEC permeability to sodium fluorescein and Evans blue albumin. These effects of metformin were blocked by compound C, an inhibitor of AMP-activated protein kinase (AMPK). AMPK stimulation with an AMPK activator, AICAR, enhanced BBB functions. These findings indicate that metformin induces up-regulation of BBB functions via AMPK activation.

  16. Three-dimensional culture conditions differentially affect astrocyte modulation of brain endothelial barrier function in response to transforming growth factor β1.

    PubMed

    Hawkins, Brian T; Grego, Sonia; Sellgren, Katelyn L

    2015-05-22

    Blood-brain barrier (BBB) function is regulated by dynamic interactions among cell types within the neurovascular unit, including astrocytes and endothelial cells. Co-culture models of the BBB typically involve astrocytes seeded on two-dimensional (2D) surfaces, which recent studies indicate cause astrocytes to express a phenotype similar to that of reactive astrocytes in situ. We hypothesized that the culture conditions of astrocytes would differentially affect their ability to modulate BBB function in vitro. Brain endothelial cells were grown alone or in co-culture with astrocytes. Astrocytes were grown either as conventional (2D) monolayers, or in a collagen-based gel which allows them to grow in a three-dimensional (3D) construct. Astrocytes were viable in 3D conditions, and displayed a marked reduction in their expression of glial fibrillary acidic protein (GFAP), suggesting reduced activation. Stimulation of astrocytes with transforming growth factor (TGF)β1 decreased transendothelial electrical resistance (TEER) and reduced expression of claudin-5 in co-cultures, whereas treatment of endothelial cells in the absence of astrocytes was without effect. The effect of TGFβ1 on TEER was significantly more pronounced in endothelial cells cultured with 3D astrocytes compared to 2D astrocytes. These results demonstrate that astrocyte culture conditions differentially affect their ability to modulate brain endothelial barrier function, and suggest a direct relationship between reactive gliosis and BBB permeability. Moreover, these studies demonstrate the potential importance of physiologically relevant culture conditions to in vitro modeling of disease processes that affect the neurovascular unit.

  17. Apoptosis of Endothelial Cells by 13-HPODE Contributes to Impairment of Endothelial Barrier Integrity

    PubMed Central

    Ryman, Valerie E.; Packiriswamy, Nandakumar

    2016-01-01

    Inflammation is an essential host response during bacterial infections such as bovine mastitis. Endothelial cells are critical for an appropriate inflammatory response and loss of vascular barrier integrity is implicated in the pathogenesis of Streptococcus uberis-induced mastitis. Previous studies suggested that accumulation of linoleic acid (LA) oxygenation products derived from 15-lipoxygenase-1 (15-LOX-1) metabolism could regulate vascular functions. The initial LA derivative from the 15-LOX-1 pathway, 13-hydroperoxyoctadecadienoic acid (HPODE), can induce endothelial death, whereas the reduced hydroxyl product, 13-hydroxyoctadecadienoic acid (HODE), is abundantly produced during vascular activation. However, the relative contribution of specific LA-derived metabolites on impairment of mammary endothelial integrity is unknown. Our hypothesis was that S. uberis-induced LA-derived 15-LOX-1 oxygenation products impair mammary endothelial barrier integrity by apoptosis. Exposure of bovine mammary endothelial cells (BMEC) to S. uberis did not increase 15-LOX-1 LA metabolism. However, S. uberis challenge of bovine monocytes demonstrated that monocytes may be a significant source of both 13-HPODE and 13-HODE during mastitis. Exposure of BMEC to 13-HPODE, but not 13-HODE, significantly reduced endothelial barrier integrity and increased apoptosis. Changing oxidant status by coexposure to an antioxidant during 13-HPODE treatment prevented adverse effects of 13-HPODE, including amelioration of apoptosis. A better understanding of how the oxidant status of the vascular microenvironment impacts endothelial barrier properties could lead to more efficacious treatments for S. uberis mastitis. PMID:27818578

  18. Crossing the endothelial barrier during metastasis.

    PubMed

    Reymond, Nicolas; d'Água, Bárbara Borda; Ridley, Anne J

    2013-12-01

    During metastasis, cancer cells disseminate to other parts of the body by entering the bloodstream in a process that is called intravasation. They then extravasate at metastatic sites by attaching to endothelial cells that line blood vessels and crossing the vessel walls of tissues or organs. This Review describes how cancer cells cross the endothelial barrier during extravasation and how different receptors, signalling pathways and circulating cells such as leukocytes and platelets contribute to this process. Identification of the mechanisms that underlie cancer cell extravasation could lead to the development of new therapies to reduce metastasis.

  19. IL-17A potentiates TNFα-induced secretion from human endothelial cells and alters barrier functions controlling neutrophils rights of passage.

    PubMed

    Bosteen, Markus H; Tritsaris, Katerina; Hansen, Anker J; Dissing, Steen

    2014-05-01

    Interleukin-17A (IL-17A) is an important pro-inflammatory cytokine that regulates leukocyte mobilization and recruitment. To better understand how IL-17A controls leukocyte trafficking across capillaries in the peripheral blood circulation, we used primary human dermal microvascular endothelial cells (HDMEC) to investigate their secretory potential and barrier function when activated with IL-17A and TNFα. Activation by TNFα and IL-17A causes phosphorylation of p38 as well as IκBα whereby NFκB subsequently becomes phosphorylated, a mechanism that initiates transcription of adhesion molecules such as E-selectin. Members of the neutrophil-specific GRO-family chemokines were significantly up-regulated upon IL-17A stimulation on the mRNA and protein level, whereas all tested non-neutrophil-specific chemokines remained unchanged in comparison. Moreover, a striking synergistic effect in the induction of granulocyte colony-stimulating factors (G-CSF) was elicited when IL-17A was used in combination with TNFα, and IL-17A was able to significantly augment the levels of TNFα-induced E-selectin and ICAM-1. In accordance with this observation, IL-17A was able to markedly increase TNFα-induced neutrophil adherence to HDMEC monolayers in an in vitro adhesion assay. Using a trans-well migration assay with an HDMEC monolayer as a barrier, we here show that pre-stimulating the endothelial cells with TNFα and IL-17A together enhances the rate of neutrophil transmigration compared to TNFα or IL-17A alone. These results show that IL-17A and TNFα act in cooperation to facilitate neutrophil migration across the endothelial cell barrier. In addition, the synergistic actions of IL-17A with TNFα to secrete G-CSF appear to be important for mobilizing neutrophils from the bone marrow to the blood stream.

  20. Vascular endothelial tight junctions and barrier function are disrupted by 15(S)-hydroxyeicosatetraenoic acid partly via protein kinase C ε-mediated zona occludens-1 phosphorylation at threonine 770/772.

    PubMed

    Chattopadhyay, Rima; Dyukova, Elena; Singh, Nikhlesh K; Ohba, Motoi; Mobley, James A; Rao, Gadiparthi N

    2014-02-07

    Disruption of tight junctions (TJs) perturbs endothelial barrier function and promotes inflammation. Previously, we have shown that 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), the major 15-lipoxygenase 1 (15-LO1) metabolite of arachidonic acid, by stimulating zona occludens (ZO)-2 tyrosine phosphorylation and its dissociation from claudins 1/5, induces endothelial TJ disruption and its barrier dysfunction. Here, we have studied the role of serine/threonine phosphorylation of TJ proteins in 15(S)-HETE-induced endothelial TJ disruption and its barrier dysfunction. We found that 15(S)-HETE enhances ZO-1 phosphorylation at Thr-770/772 residues via PKCε-mediated MEK1-ERK1/2 activation, causing ZO-1 dissociation from occludin, disrupting endothelial TJs and its barrier function, and promoting monocyte transmigration; these effects were reversed by T770A/T772A mutations. In the arteries of WT mice ex vivo, 15(S)-HETE also induced ZO-1 phosphorylation and endothelial TJ disruption in a PKCε and MEK1-ERK1/2-dependent manner. In line with these observations, in WT mice high fat diet feeding induced 12/15-lipoxygenase (12/15-LO) expression in the endothelium and caused disruption of its TJs and barrier function. However, in 12/15-LO(-/-) mice, high fat diet feeding did not cause disruption of endothelial TJs and barrier function. These observations suggest that the 12/15-LO-12/15(S)-HETE axis, in addition to tyrosine phosphorylation of ZO-2, also stimulates threonine phosphorylation of ZO-1 in the mediation of endothelial TJ disruption and its barrier dysfunction.

  1. [In vitro study of endothelial tolerance of 10 culture media with special reference to the pump and barrier function].

    PubMed

    Kloss, A; Böhnke, M

    1991-01-01

    We investigated ten commercially available tissue culture media in a series of perfusion experiments. Porcine cornea were perfused in groups of 10-15 with the media M 199 Earle, MEM Earle, MEM Hank, DMEM, RPMI 1640, Ham's F-12, BM-86 Wissler. Perfusions were done with and without the addition of 2% fetal calf serum. As a control, BSS PLUS (R) was used. We compared the change in corneal thickness in a 6-h perfusion interval. The corneal endothelium was present after all perfusion experiments. Evaluation of the changes in corneal thickness showed that culture media rich in bicarbonate support the endothelial pumping function. The presence of fetal calf serum had no influence on corneal thickness. The absence of glutathione in the culture media did not result in increased corneal thickness. Medium 199 with Earle salt, BSS Plus, DMEM, RPMI 1640 and Ham's F-12 gave the best results and may be considered possible intraocular irrigation solutions.

  2. Regulation on Toll-like Receptor 4 and Cell Barrier Function by Rab26 siRNA-loaded DNA Nanovector in Pulmonary Microvascular Endothelial Cells.

    PubMed

    Li, Hongli; He, Binfeng; Liu, Xueping; Li, Jingtong; Liu, Qian; Dong, Weijie; Xu, Zhi; Qian, Guisheng; Zuo, Hua; Hu, Changhua; Qian, Hang; Mao, Chengde; Wang, Guansong

    2017-01-01

    The small GTPase Rab26 is involved in multiple processes, such as vesicle-mediated secretion and autophagy. However, the mechanisms and functions of Rab26 in the human pulmonary microvascular endothelial cells (HPMVECs) are not clear. In this study, we thoroughly investigated the role and novel mechanism of Rab26 in permeability and apoptosis of HPMVECs using a self-assembled Rab26 siRNA loaded DNA Y-motif nanoparticle (siRab26-DYM) and Rab26 adenovirus. We found that siRab26-DYM could be efficiently transfected into HPMVECs in a time- and dose-dependent manner. Importantly, the siRab26-DYM nanovector markedly aggravated the LPS-induced apoptosis and hyper-permeability of HPMVECs by promoting the nuclear translocation of Foxo1, and subsequent activation of Toll-like receptor 4 (TLR4) signal pathway. Overexpression of Rab26 by Rab26 adenoviruses partially inactivated LPS-induced TLR4 signaling pathway, suppressed the cell apoptosis and attenuated the hyperpermeability of HPMVECs. These results suggest that the permeability and apoptosis of HPMVECs can be modulated by manipulating Rab26 derived TLR4 signaling pathway, and that Rab26 can be potential therapeutic target for the treatment of vascular diseases related to endothelial barrier functions.

  3. eNOS-derived nitric oxide regulates endothelial barrier function through VE-cadherin and Rho GTPases

    PubMed Central

    Di Lorenzo, Annarita; Lin, Michelle I.; Murata, Takahisa; Landskroner-Eiger, Shira; Schleicher, Michael; Kothiya, Milankumar; Iwakiri, Yasuko; Yu, Jun; Huang, Paul L.; Sessa, William C.

    2013-01-01

    Summary Transient disruption of endothelial adherens junctions and cytoskeletal remodeling are responsible for increases in vascular permeability induced by inflammatory stimuli and vascular endothelial growth factor (VEGF). Nitric oxide (NO) produced by endothelial NO synthase (eNOS) is crucial for VEGF-induced changes in permeability in vivo; however, the molecular mechanism by which endogenous NO modulates endothelial permeability is not clear. Here, we show that the lack of eNOS reduces VEGF-induced permeability, an effect mediated by enhanced activation of the Rac GTPase and stabilization of cortical actin. The loss of NO increased the recruitment of the Rac guanine-nucleotide-exchange factor (GEF) TIAM1 to adherens junctions and VE-cadherin (also known as cadherin 5), and reduced Rho activation and stress fiber formation. In addition, NO deficiency reduced VEGF-induced VE-cadherin phosphorylation and impaired the localization, but not the activation, of c-Src to cell junctions. The physiological role of eNOS activation is clear given that VEGF-, histamine- and inflammation-induced vascular permeability is reduced in mice bearing a non-phosphorylatable knock-in mutation of the key eNOS phosphorylation site S1176. Thus, NO is crucial for Rho GTPase-dependent regulation of cytoskeletal architecture leading to reversible changes in vascular permeability. PMID:24046447

  4. Using cultured endothelial cells to study endothelial barrier dysfunction: Challenges and opportunities

    PubMed Central

    Weijers, Ester M.; van Nieuw Amerongen, Geerten P.; Malik, Asrar B.; van Hinsbergh, Victor W. M.

    2016-01-01

    Despite considerable progress in the understanding of endothelial barrier regulation and the identification of approaches that have the potential to improve endothelial barrier function, no drug- or stem cell-based therapy is presently available to reverse the widespread vascular leak that is observed in acute respiratory distress syndrome (ARDS) and sepsis. The translational gap suggests a need to develop experimental approaches and tools that better mimic the complex environment of the microcirculation in which the vascular leak develops. Recent studies have identified several elements of this microenvironment. Among these are composition and stiffness of the extracellular matrix, fluid shear stress, interaction of endothelial cells (ECs) with pericytes, oxygen tension, and the combination of toxic and mechanic injurious stimuli. Development of novel cell culture techniques that integrate these elements would allow in-depth analysis of EC biology that closely approaches the (patho)physiological conditions in situ. In parallel, techniques to isolate organ-specific ECs, to define EC heterogeneity in its full complexity, and to culture patient-derived ECs from inducible pluripotent stem cells or endothelial progenitor cells are likely to advance the understanding of ARDS and lead to development of therapeutics. This review 1) summarizes the advantages and pitfalls of EC cultures to study vascular leak in ARDS, 2) provides an overview of elements of the microvascular environment that can directly affect endothelial barrier function, and 3) discusses alternative methods to bridge the gap between basic research and clinical application with the intent of improving the translational value of present EC culture approaches. PMID:27343194

  5. Endothelial Progenitor Cells Physiology and Metabolic Plasticity in Brain Angiogenesis and Blood-Brain Barrier Modeling

    PubMed Central

    Malinovskaya, Natalia A.; Komleva, Yulia K.; Salmin, Vladimir V.; Morgun, Andrey V.; Shuvaev, Anton N.; Panina, Yulia A.; Boitsova, Elizaveta B.; Salmina, Alla B.

    2016-01-01

    Currently, there is a considerable interest to the assessment of blood-brain barrier (BBB) development as a part of cerebral angiogenesis developmental program. Embryonic and adult angiogenesis in the brain is governed by the coordinated activity of endothelial progenitor cells, brain microvascular endothelial cells, and non-endothelial cells contributing to the establishment of the BBB (pericytes, astrocytes, neurons). Metabolic and functional plasticity of endothelial progenitor cells controls their timely recruitment, precise homing to the brain microvessels, and efficient support of brain angiogenesis. Deciphering endothelial progenitor cells physiology would provide novel engineering approaches to establish adequate microfluidically-supported BBB models and brain microphysiological systems for translational studies. PMID:27990124

  6. RhoA S-nitrosylation as a regulatory mechanism influencing endothelial barrier function in response to G(+)-bacterial toxins.

    PubMed

    Chen, F; Wang, Y; Rafikov, R; Haigh, S; Zhi, W B; Kumar, S; Doulias, P T; Rafikova, O; Pillich, H; Chakraborty, T; Lucas, R; Verin, A D; Catravas, J D; She, J X; Black, S M; Fulton, D J R

    2017-03-01

    Disruption of the endothelial barrier in response to Gram positive (G(+)) bacterial toxins is a major complication of acute lung injury (ALI) and can be further aggravated by antibiotics which stimulate toxin release. The integrity of the pulmonary endothelial barrier is mediated by the balance of disruptive forces such as the small GTPase RhoA, and protective forces including endothelium-derived nitric oxide (NO). How NO protects against the barrier dysfunction is incompletely understood and our goal was to determine whether NO and S-nitrosylation can modulate RhoA activity and whether this mechanism is important for G(+) toxin-induced microvascular permeability. We found that the G(+) toxin listeriolysin-O (LLO) increased RhoA activity and that NO and S-NO donors inhibit RhoA activity. RhoA was robustly S-nitrosylated as determined by biotin-switch and mercury column analysis. MS revealed that three primary cysteine residues are S-nitrosylated including cys16, cys20 and cys159. Mutation of these residues to serine diminished S-nitrosylation to endogenous NO and mutant RhoA was less sensitive to inhibition by S-NO. G(+)-toxins stimulated the denitrosylation of RhoA which was not mediated by S-nitrosoglutathione reductase (GSNOR), thioredoxin (TRX) or thiol-dependent enzyme activity but was instead stimulated directly by elevated calcium levels. Calcium-promoted the direct denitrosylation of WT but not mutant RhoA and mutant RhoA adenovirus was more effective than WT in disrupting the barrier integrity of human lung microvascular endothelial cells. In conclusion, we reveal a novel mechanism by which NO and S-nitrosylation reduces RhoA activity which may be of significance in the management of pulmonary endothelial permeability induced by G(+)-toxins. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. RhoB controls endothelial barrier recovery by inhibiting Rac1 trafficking to the cell border

    PubMed Central

    Marcos-Ramiro, Beatriz; García-Weber, Diego; Barroso, Susana; Feito, Jorge; Ortega, María C.; Cernuda-Morollón, Eva; Reglero-Real, Natalia; Fernández-Martín, Laura; Durán, Maria C.; Alonso, Miguel A.; Correas, Isabel; Cox, Susan; Ridley, Anne J.

    2016-01-01

    Endothelial barrier dysfunction underlies chronic inflammatory diseases. In searching for new proteins essential to the human endothelial inflammatory response, we have found that the endosomal GTPase RhoB is up-regulated in response to inflammatory cytokines and expressed in the endothelium of some chronically inflamed tissues. We show that although RhoB and the related RhoA and RhoC play additive and redundant roles in various aspects of endothelial barrier function, RhoB specifically inhibits barrier restoration after acute cell contraction by preventing plasma membrane extension. During barrier restoration, RhoB trafficking is induced between vesicles containing RhoB nanoclusters and plasma membrane protrusions. The Rho GTPase Rac1 controls membrane spreading and stabilizes endothelial barriers. We show that RhoB colocalizes with Rac1 in endosomes and inhibits Rac1 activity and trafficking to the cell border during barrier recovery. Inhibition of endosomal trafficking impairs barrier reformation, whereas induction of Rac1 translocation to the plasma membrane accelerates it. Therefore, RhoB-specific regulation of Rac1 trafficking controls endothelial barrier integrity during inflammation. PMID:27138256

  8. Ethanol Disrupts Vascular Endothelial Barrier: Implication in Cancer Metastasis

    PubMed Central

    Xu, Mei; Chen, Gang; Fu, Wei; Liao, Mingjun; Frank, Jacqueline A.; Bower, Kimberly A.; Fang, Shengyun; Zhang, Zhuo; Shi, Xianglin; Luo, Jia

    2012-01-01

    Both epidemiological and experimental studies indicate that ethanol exposure enhances tumor progression. Ethanol exposure promotes cancer cell invasion and is implicated in tumor metastasis. Metastasis consists of multiple processes involving intravasation and extravasation of cancer cells across the blood vessel walls. The integrity of the vascular endothelial barrier that lines the inner surface of blood vessels plays a critical role in cancer cell intravasation/extravasation. We examined the effects of ethanol on the endothelial integrity in vitro. Ethanol at physiologically relevant concentrations did not alter cell viability but disrupted the endothelial monolayer integrity, which was evident by a decrease in the electric resistance and the appearance of intercellular gaps in the endothelial monolayer. The effect of ethanol was reversible once ethanol was removed. The disruption of the endothelial monolayer integrity was associated with an increased invasion of cancer cells through the endothelial monolayer. Ethanol induced the formation of stress fibers; stabilization of actin filaments by jasplakinolide prevented ethanol-induced disruption of endothelial integrity and cancer cell invasion. VE-cadherin is a critical component of the adherens junctions, which regulates vascular endothelial integrity. Ethanol induced the endocytosis of VE-cadherin and the effect was blocked by jasplakinolide. Our results indicate that ethanol may facilitate cancer metastasis by disrupting the vascular endothelial barrier. PMID:22331491

  9. Lung endothelial cells strengthen, but brain endothelial cells weaken barrier properties of a human alveolar epithelium cell culture model.

    PubMed

    Neuhaus, Winfried; Samwer, Fabian; Kunzmann, Steffen; Muellenbach, Ralf M; Wirth, Michael; Speer, Christian P; Roewer, Norbert; Förster, Carola Y

    2012-11-01

    The blood-air barrier in the lung consists of the alveolar epithelium, the underlying capillary endothelium, their basement membranes and the interstitial space between the cell layers. Little is known about the interactions between the alveolar and the blood compartment. The aim of the present study was to gain first insights into the possible interplay between these two neighbored cell layers. We established an in vitro Transwell model of the alveolar epithelium based on human cell line H441 and investigated the influence of conditioned medium obtained from human lung endothelial cell line HPMEC-ST1.6R on the barrier properties of the H441 layers. As control for tissue specificity H441 layers were exposed to conditioned medium from human brain endothelial cell line hCMEC/D3. Addition of dexamethasone was necessary to obtain stable H441 cell layers. Moreover, dexamethasone increased expression of cell type I markers (caveolin-1, RAGE) and cell type II marker SP-B, whereas decreased the transepithelial electrical resistance (TEER) in a concentration dependent manner. Soluble factors obtained from the lung endothelial cell line increased the barrier significantly proven by TEER values and fluorescein permeability on the functional level and by the differential expression of tight junctional proteins on the molecular level. In contrast to this, soluble factors derived from brain endothelial cells weakened the barrier significantly. In conclusion, soluble factors from lung endothelial cells can strengthen the alveolar epithelium barrier in vitro, which suggests communication between endothelial and epithelial cells regulating the integrity of the blood-air barrier.

  10. Cannabidiol attenuates high glucose-induced endothelial cell inflammatory response and barrier disruption.

    PubMed

    Rajesh, Mohanraj; Mukhopadhyay, Partha; Bátkai, Sándor; Haskó, György; Liaudet, Lucas; Drel, Viktor R; Obrosova, Irina G; Pacher, Pál

    2007-07-01

    A nonpsychoactive cannabinoid cannabidiol (CBD) has been shown to exert potent anti-inflammatory and antioxidant effects and has recently been reported to lower the incidence of diabetes in nonobese diabetic mice and to preserve the blood-retinal barrier in experimental diabetes. In this study we have investigated the effects of CBD on high glucose (HG)-induced, mitochondrial superoxide generation, NF-kappaB activation, nitrotyrosine formation, inducible nitric oxide synthase (iNOS) and adhesion molecules ICAM-1 and VCAM-1 expression, monocyte-endothelial adhesion, transendothelial migration of monocytes, and disruption of endothelial barrier function in human coronary artery endothelial cells (HCAECs). HG markedly increased mitochondrial superoxide generation (measured by flow cytometry using MitoSOX), NF-kappaB activation, nitrotyrosine formation, upregulation of iNOS and adhesion molecules ICAM-1 and VCAM-1, transendothelial migration of monocytes, and monocyte-endothelial adhesion in HCAECs. HG also decreased endothelial barrier function measured by increased permeability and diminished expression of vascular endothelial cadherin in HCAECs. Remarkably, all the above mentioned effects of HG were attenuated by CBD pretreatment. Since a disruption of the endothelial function and integrity by HG is a crucial early event underlying the development of various diabetic complications, our results suggest that CBD, which has recently been approved for the treatment of inflammation, pain, and spasticity associated with multiple sclerosis in humans, may have significant therapeutic benefits against diabetic complications and atherosclerosis.

  11. Dephosphorylation of Y685-VE-Cadherin Involved in Pulmonary Microvascular Endothelial Barrier Injury Induced by Angiotensin II

    PubMed Central

    Wang, Zhiwei; Dai, Feifeng; Liu, Huagang; Ren, Wei; Chang, Jinxing; Li, Bowen

    2016-01-01

    Angiotensin II (AngII) caused pulmonary microvascular endothelial barrier injury, which induced acute aortic dissection (AAD) combined with acute lung injury (ALI). However, the exact mechanism is unclear. We investigated the role of dephosphorylation of Y685-VE-cadherin in the AngII induced pulmonary microvascular endothelial barrier injury. Mice or pulmonary microvascular endothelial cells (PMVECs) were divided into control group, AngII group, AngII+PP2 (Src kinase inhibitor) group, and PP2 group. PP2 was used to inhibit the phosphorylation of Y685-VE-cadherin. Pathological changes, infiltration of macrophages and neutrophils, and pulmonary microvascular permeability were used to determine the pulmonary microvascular endothelial barrier function. Flow cytometry was used to determine the apoptosis of PMVECs, and immunofluorescence was used to determine the skeletal arrangement. Transendothelial resistance was used to detect the permeability of endothelial barrier. Phosphorylation of Y685-VE-cadherin was significantly reduced after AngII stimulation (P < 0.05), together with skeletal rearrangement, and elevation of endothelial permeability which finally induced endothelial barrier injury. After PP2 interference, the phosphorylation of Y685-VE-cadherin was further reduced and the endothelial permeability was further elevated. These data indicated that AngII could induce pulmonary injury by triggering endothelial barrier injury, and such process may be related to the dephosphorylation of Y685-VE-cadherin and the endothelial skeletal rearrangement. PMID:28119542

  12. Dephosphorylation of Y685-VE-Cadherin Involved in Pulmonary Microvascular Endothelial Barrier Injury Induced by Angiotensin II.

    PubMed

    Wu, Zhiyong; Wang, Zhiwei; Dai, Feifeng; Liu, Huagang; Ren, Wei; Chang, Jinxing; Li, Bowen

    2016-01-01

    Angiotensin II (AngII) caused pulmonary microvascular endothelial barrier injury, which induced acute aortic dissection (AAD) combined with acute lung injury (ALI). However, the exact mechanism is unclear. We investigated the role of dephosphorylation of Y685-VE-cadherin in the AngII induced pulmonary microvascular endothelial barrier injury. Mice or pulmonary microvascular endothelial cells (PMVECs) were divided into control group, AngII group, AngII+PP2 (Src kinase inhibitor) group, and PP2 group. PP2 was used to inhibit the phosphorylation of Y685-VE-cadherin. Pathological changes, infiltration of macrophages and neutrophils, and pulmonary microvascular permeability were used to determine the pulmonary microvascular endothelial barrier function. Flow cytometry was used to determine the apoptosis of PMVECs, and immunofluorescence was used to determine the skeletal arrangement. Transendothelial resistance was used to detect the permeability of endothelial barrier. Phosphorylation of Y685-VE-cadherin was significantly reduced after AngII stimulation (P < 0.05), together with skeletal rearrangement, and elevation of endothelial permeability which finally induced endothelial barrier injury. After PP2 interference, the phosphorylation of Y685-VE-cadherin was further reduced and the endothelial permeability was further elevated. These data indicated that AngII could induce pulmonary injury by triggering endothelial barrier injury, and such process may be related to the dephosphorylation of Y685-VE-cadherin and the endothelial skeletal rearrangement.

  13. Terminal sialic acids are an important determinant of pulmonary endothelial barrier integrity

    PubMed Central

    Cioffi, Donna L.; Pandey, Subha; Alvarez, Diego F.

    2012-01-01

    The surface of vascular endothelium bears a glycocalyx comprised, in part, of a complex mixture of oligosaccharide chains attached to cell-surface proteins and membrane lipids. Importantly, understanding of the structure and function of the endothelial glycocalyx is poorly understood. Preliminary studies have demonstrated structural differences in the glycocalyx of pulmonary artery endothelial cells compared with pulmonary microvascular endothelial cells. Herein we begin to probe in more detail structural and functional attributes of endothelial cell-surface carbohydrates. In this study we focus on the expression and function of sialic acids in pulmonary endothelium. We observed that, although pulmonary microvascular endothelial cells express similar amounts of total sialic acids as pulmonary artery endothelial cells, the nature of the sialic acid linkages differs between the two cell types such that pulmonary artery endothelial cells express both α(2,3)- and α(2,6)-linked sialic acids on the surface (i.e., surficially), whereas microvascular endothelial cells principally express α(2,3)-linked sialic acids. To determine whether sialic acids play a role in endothelial barrier function, cells were treated with neuraminidases to hydrolyze sialic acid moieties. Disruption of cell-cell and cell-matrix adhesions was observed following neuraminidase treatment, suggesting that terminal sialic acids promote endothelial barrier integrity. When we measured transendothelial resistance, differential responses of pulmonary artery and microvascular endothelial cells to neuraminidase from Clostridium perfringens suggest that the molecular architecture of the sialic acid glycomes differs between these two cell types. Collectively our observations reveal critical structural and functional differences of terminally linked sialic acids on the pulmonary endothelium. PMID:22387293

  14. Endothelial RIG-I activation impairs endothelial function

    SciTech Connect

    Asdonk, Tobias; Nickenig, Georg; Zimmer, Sebastian

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer RIG-I activation impairs endothelial function in vivo. Black-Right-Pointing-Pointer RIG-I activation alters HCAEC biology in vitro. Black-Right-Pointing-Pointer EPC function is affected by RIG-I stimulation in vitro. -- Abstract: Background: Endothelial dysfunction is a crucial part of the chronic inflammatory atherosclerotic process and is mediated by innate and acquired immune mechanisms. Recent studies suggest that pattern recognition receptors (PRR) specialized in immunorecognition of nucleic acids may play an important role in endothelial biology in a proatherogenic manner. Here, we analyzed the impact of endothelial retinoic acid inducible gene I (RIG-I) activation upon vascular endothelial biology. Methods and results: Wild type mice were injected intravenously with 32.5 {mu}g of the RIG-ligand 3pRNA (RNA with triphosphate at the 5 Prime end) or polyA control every other day for 7 days. In 3pRNA-treated mice, endothelium-depended vasodilation was significantly impaired, vascular oxidative stress significantly increased and circulating endothelial microparticle (EMP) numbers significantly elevated compared to controls. To gain further insight in RIG-I dependent endothelial biology, cultured human coronary endothelial cells (HCAEC) and endothelial progenitor cells (EPC) were stimulated in vitro with 3pRNA. Both cells types express RIG-I and react with receptor upregulation upon stimulation. Reactive oxygen species (ROS) formation is enhanced in both cell types, whereas apoptosis and proliferation is not significantly affected in HCAEC. Importantly, HCAEC release significant amounts of proinflammatory cytokines in response to RIG-I stimulation. Conclusion: This study shows that activation of the cytoplasmatic nucleic acid receptor RIG-I leads to endothelial dysfunction. RIG-I induced endothelial damage could therefore be an important pathway in atherogenesis.

  15. Intracellular Ascorbate Prevents Endothelial Barrier Permeabilization by Thrombin*

    PubMed Central

    Parker, William H.; Qu, Zhi-chao; May, James M.

    2015-01-01

    Intracellular ascorbate (vitamin C) has previously been shown to tighten the endothelial barrier and maintain barrier integrity during acute inflammation in vitro. However, the downstream effectors of ascorbate in the regulation of endothelial permeability remain unclear. In this study, we evaluated ascorbate as a mediator of thrombin-induced barrier permeabilization in human umbilical vein endothelial cells and their immortalized hybridoma line, EA.hy926. We found that the vitamin fully prevented increased permeability to the polysaccharide inulin by thrombin in a dose-dependent manner, and it took effect both before and after subjection to thrombin. Thrombin exposure consumed intracellular ascorbate but not the endogenous antioxidant GSH. Likewise, the antioxidants dithiothreitol and tempol did not reverse permeabilization. We identified a novel role for ascorbate in preserving cAMP during thrombin stimulation, resulting in two downstream effects. First, ascorbate maintained the cortical actin cytoskeleton in a Rap1- and Rac1-dependent manner, thus preserving stable adherens junctions between adjacent cells. Second, ascorbate prevented actin polymerization and formation of stress fibers by reducing the activation of RhoA and phosphorylation of myosin light chain. Although ascorbate and thrombin both required calcium for their respective effects, ascorbate did not prevent thrombin permeabilization by obstructing calcium influx. However, preservation of cAMP by ascorbate was found to depend on both the production of nitric oxide by endothelial nitric-oxide synthase, which ascorbate is known to activate, and the subsequent generation cGMP by guanylate cyclase. Together, these data implicate ascorbate in the prevention of inflammatory endothelial barrier permeabilization and explain the underlying signaling mechanism. PMID:26152729

  16. Intracellular Ascorbate Prevents Endothelial Barrier Permeabilization by Thrombin.

    PubMed

    Parker, William H; Qu, Zhi-chao; May, James M

    2015-08-28

    Intracellular ascorbate (vitamin C) has previously been shown to tighten the endothelial barrier and maintain barrier integrity during acute inflammation in vitro. However, the downstream effectors of ascorbate in the regulation of endothelial permeability remain unclear. In this study, we evaluated ascorbate as a mediator of thrombin-induced barrier permeabilization in human umbilical vein endothelial cells and their immortalized hybridoma line, EA.hy926. We found that the vitamin fully prevented increased permeability to the polysaccharide inulin by thrombin in a dose-dependent manner, and it took effect both before and after subjection to thrombin. Thrombin exposure consumed intracellular ascorbate but not the endogenous antioxidant GSH. Likewise, the antioxidants dithiothreitol and tempol did not reverse permeabilization. We identified a novel role for ascorbate in preserving cAMP during thrombin stimulation, resulting in two downstream effects. First, ascorbate maintained the cortical actin cytoskeleton in a Rap1- and Rac1-dependent manner, thus preserving stable adherens junctions between adjacent cells. Second, ascorbate prevented actin polymerization and formation of stress fibers by reducing the activation of RhoA and phosphorylation of myosin light chain. Although ascorbate and thrombin both required calcium for their respective effects, ascorbate did not prevent thrombin permeabilization by obstructing calcium influx. However, preservation of cAMP by ascorbate was found to depend on both the production of nitric oxide by endothelial nitric-oxide synthase, which ascorbate is known to activate, and the subsequent generation cGMP by guanylate cyclase. Together, these data implicate ascorbate in the prevention of inflammatory endothelial barrier permeabilization and explain the underlying signaling mechanism.

  17. Genetic Regulation of Endothelial Vasomotor Function

    PubMed Central

    Kim, Seung Kyum; Massett, Michael P.

    2016-01-01

    The endothelium plays an important role in the regulation of vasomotor tone and the maintenance of vascular integrity. Endothelial dysfunction, i.e., impaired endothelial dependent dilation, is a fundamental component of the pathogenesis of cardiovascular disease. Although endothelial dysfunction is associated with a number of cardiovascular disease risk factors, those risk factors are not the only determinants of endothelial dysfunction. Despite knowing many molecules involved in endothelial signaling pathways, the genetic contribution to endothelial function has yet to be fully elucidated. This mini-review summarizes current evidence supporting the genetic contribution to endothelial vasomotor function. Findings from population-based studies, association studies for candidate genes, and unbiased large genomic scale studies in humans and rodent models are discussed. A brief synopsis of the current studies addressing the genetic regulation of endothelial responses to exercise training is also included. PMID:27932996

  18. Regulation of Endothelial Barrier Function by TGF-β type I Receptor ALK5: Potential Role of Contractile Mechanisms and Heat Shock Protein 90

    PubMed Central

    Antonov, Alexander S.; Antonova, Galina N.; Fujii, Makiko; Dijke, Peter ten; Handa, Vaishali; Catravas, John D.; Verin, Alexander D.

    2013-01-01

    Multifunctional cytokine transforming growth factor-beta (TGF-β1) plays a critical role in the pathogenesis of acute lung inflammation by controlling endothelial monolayer permeability. TGF-β1 regulates endothelial cell (EC) functions via two distinct receptors, activin receptor-like kinase 1 (ALK1) and activin receptor-like kinase 5 (ALK5). The precise roles of ALK1 and ALK5 in the regulation of TGF-β1-induced lung endothelium dysfunction remain mostly unknown. We now report that adenoviral infection with constitutively active ALK5 (caALK5), but not caALK1, induces EC retraction and that this receptor predominantly controls EC permeability. We demonstrate that ubiquitinated ALK5 and phosphorylated heat shock protein 27 (phospho-Hsp27) specifically accumulate in the cytoskeleton fraction, which parallels with microtubule collapse, cortical actin disassembly and increased EC permeability. We have found that ALK1 and ALK5 interact with heat shock protein 90 (Hsp90). Moreover, the Hsp90 inhibitor radicicol (RA) prevents accumulation of ubiquitinated caALK5 and phospho-Hsp27 in the cytoskeletal fraction and restore the decreased EC permeability induced by caALK5. We hypothesize that specific translocation of ubiquitinated ALK5 receptor into the cytoskeleton compartment due to its lack of degradation is the mechanism that causes the divergence of caALK1 and caALK5 signaling. PMID:21465483

  19. Protein kinase C-mediated endothelial barrier regulation is caveolin-1-dependent.

    PubMed

    Waschke, Jens; Golenhofen, Nikola; Kurzchalia, Teymuras V; Drenckhahn, Detlev

    2006-07-01

    Protein kinase C (PKC) is activated in response to various inflammatory mediators and contributes significantly to the endothelial barrier breakdown. However, the mechanisms underlying PKC-mediated permeability regulation are not well understood. We prepared microvascular myocardial endothelial cells from both wild-type (WT) and caveolin-1-deficient mice. Activation of PKC by phorbol myristate acetate (PMA) (100 nM) for 30 min induced intercellular gap formation and fragmentation of VE-cadherin immunoreactivity in WT but not in caveolin-1-deficient monolayers. To test the effect of PKC activation on VE-cadherin-mediated adhesion, we allowed VE-cadherin-coated microbeads to bind to the endothelial cell surface and probed their adhesion by laser tweezers. PMA significantly reduced bead binding to 78+/-6% of controls in WT endothelial cells without any effect in caveolin-1-deficient cells. In WT cells, PMA caused an 86+/-18% increase in FITC-dextran permeability whereas no increase in permeability was observed in caveolin-1-deficient monolayers. Inhibition of PKC by staurosporine (50 nM, 30 min) did not affect barrier functions in both WT and caveolin-1-deficient MyEnd cells. Theses data indicate that PKC activation reduces endothelial barrier functions at least in part by the reduction of VE-cadherin-mediated adhesion and demonstrate that PKC-mediated permeability regulation depends on caveolin-1.

  20. Astrocytes contribute to Aβ-induced blood-brain barrier damage through activation of endothelial MMP9.

    PubMed

    Spampinato, Simona Federica; Merlo, Sara; Sano, Yasuteru; Kanda, Takashi; Sortino, Maria Angela

    2017-08-01

    The blood-brain barrier (BBB) plays an important role in the maintenance of the brain homeostasis, and its proper functions are warranted by the interplay between different cellular components (endothelial cells, astrocytes and pericytes). BBB dysfunctions in pathological conditions, and particularly in Alzheimer's disease, have been documented. Here, using an in vitroBBB model, the interaction between endothelial cells and astrocytes exposed to Aβ1-42 was investigated. Human endothelial cells, cultured in monolayer or co-cultured with astrocytes, were exposed to Aβ1-42 (2 μM for 18 h). Aβ induced dysfunction of endothelial barrier, as assessed by enhanced permeability to FITC-conjugated dextran and reduced expression of claudin-5; these modifications were observed in the co-culture model, but not in endothelial cells cultured in monolayer. Similarly, Aβ-induced damage at the barrier was observed when endothelial cells were challenged in the presence of conditioned medium generated by astrocytes previously exposed to Aβ (ACM Aβ). Endothelial barrier damages were associated with enhanced matrix metalloprotease 9 (MMP9) activity, known to mediate claudin-5 disruption. These events were not related to the direct effects played by Aβ on endothelial cells, but they were rather the consequence of Aβ-induced vascular endothelial growth factor (VEGF) expression in astrocytes. Indeed, when vascular endothelial growth factor expression was down-regulated in astrocytes, neither barrier properties or MMP9 expression in endothelial cells were affected after Aβ exposure both in the co-culture model or in the presence of ACM Aβ. These data point out the importance of astrocytes' mediation in inducing endothelial sensitivity to Aβ1-42. © 2017 International Society for Neurochemistry.

  1. Vascular endothelial growth factor blockade alters magnetic resonance imaging biomarkers of vascular function and decreases barrier permeability in a rat model of lung cancer brain metastasis.

    PubMed

    Pishko, Gregory L; Muldoon, Leslie L; Pagel, Michael A; Schwartz, Daniel L; Neuwelt, Edward A

    2015-02-17

    Blockade of vascular endothelial growth factor (VEGF) to promote vascular normalization and inhibit angiogenesis has been proposed for the treatment of brain metastases; however, vascular normalization has not been well-characterized in this disease. We investigated the effect of treatment with bevacizumab anti-VEGF antibody on magnetic resonance imaging (MRI) biomarkers of brain tumor vascular characteristics in comparison to small molecule delivery in a rat model of human lung cancer brain metastasis. Athymic rats with A549 human lung adenocarcinoma intracerebral xenografts underwent MRI at 11.75 T before and one day after treatment with bevacizumab (n = 8) or saline control (n = 8) to evaluate tumor volume, free water content (edema), blood volume and vascular permeability (Ktrans). One day later, permeability to 14C-aminoisobutyric acid (AIB) was measured in tumor and brain to assess the penetration of a small drug-like molecule. In saline control animals, tumor volume, edema and permeability increased over the two day assessment period. Compared to controls, bevacizumab treatment slowed the rate of tumor growth (P = 0.003) and blocked the increase in edema (P = 0.033), but did not alter tumor blood volume. Bevacizumab also significantly reduced Ktrans (P = 0.033) and AIB passive permeability in tumor (P = 0.04), but not to peritumoral tissue or normal brain. Post-treatment Ktrans correlated with AIB levels in the bevacizumab-treated rats but not in the saline controls. The correlation of an MRI biomarker for decreased vascular permeability with decreased AIB concentration in tumor after antiangiogenic treatment suggests that bevacizumab partially restored the normal low permeability characteristics of the blood-brain barrier in a model of human lung cancer brain metastasis.

  2. Effects of Escherichia coli hemolysin on endothelial cell function.

    PubMed Central

    Suttorp, N; Flöer, B; Schnittler, H; Seeger, W; Bhakdi, S

    1990-01-01

    Escherichia coli hemolysin is considered an important virulence factor in extraintestinal E. coli infections. The present study demonstrates that cultured pulmonary artery endothelial cells are susceptible to attack by low concentrations of E. coli hemolysin (greater than or equal to 0.05 hemolytic units/ml; greater than or equal to 5 ng/ml). Sublytic amounts of hemolysin increased the permeability of endothelial cell monolayers in a time- and dose-dependent manner. The hydraulic conductivity increased approximately 30-fold and the reflection coefficient for large molecules dropped from 0.71 to less than 0.05, indicating a toxin-induced loss of endothelial barrier function. The alterations of endothelial monolayer permeability were accompanied by cell retraction and interendothelial gap formation. In addition, E. coli hemolysin stimulated prostacyclin synthesis in endothelial cells. This effect was strictly dependent on the presence of extracellular Ca2+ but not of Mg2+. An enhanced passive influx of 45Ca2+ and 3H-sucrose but not of tritiated inulin and dextran was noted in toxin-treated cells, indicating that small transmembrane pores comparable to those detected in rabbit erythrocytes had been generated in endothelial cell membranes. These pores may act as nonphysiologic Ca2+ gates, thereby initiating different Ca2+-dependent cellular processes. We conclude that endothelial cells are highly susceptible to E. coli hemolysin and that two major endothelial cell functions are altered by very low concentrations of hemolysin. Images PMID:2121650

  3. Skin Barrier Function

    PubMed Central

    Elias, Peter M.

    2010-01-01

    Like other inflammatory dermatoses, the pathogenesis of atopic dermatitis (AD) has been largely attributed to abnormalities in adaptive immunity. T helper (Th) cell types 1 and 2 cell dysregulation, IgE production, mast cell hyperactivity, and dendritic cell signaling are thought to account for the chronic, pruritic, and inflammatory dermatosis that characterizes AD. Not surprisingly, therapy has been directed toward ameliorating Th2-mediated inflammation and pruritus. Here, we review emerging evidence that inflammation in AD occurs downstream to inherited and acquired insults to the barrier. Therapy based upon this new view of pathogenesis should emphasize approaches that correct the primary abnormality in barrier function, which drives downstream inflammation and allows unrestricted antigen access. PMID:18606081

  4. Nox2-dependent glutathionylation of endothelial NOS leads to uncoupled superoxide production and endothelial barrier dysfunction in acute lung injury.

    PubMed

    Wu, Feng; Szczepaniak, William S; Shiva, Sruti; Liu, Huanbo; Wang, Yinna; Wang, Ling; Wang, Ying; Kelley, Eric E; Chen, Alex F; Gladwin, Mark T; McVerry, Bryan J

    2014-12-15

    Microvascular barrier integrity is dependent on bioavailable nitric oxide (NO) produced locally by endothelial NO synthase (eNOS). Under conditions of limited substrate or cofactor availability or by enzymatic modification, eNOS may become uncoupled, producing superoxide in lieu of NO. This study was designed to investigate how eNOS-dependent superoxide production contributes to endothelial barrier dysfunction in inflammatory lung injury and its regulation. C57BL/6J mice were challenged with intratracheal LPS. Bronchoalveolar lavage fluid was analyzed for protein accumulation, and lung tissue homogenate was assayed for endothelial NOS content and function. Human lung microvascular endothelial cell (HLMVEC) monolayers were exposed to LPS in vitro, and barrier integrity and superoxide production were measured. Biopterin species were quantified, and coimmunoprecipitation (Co-IP) assays were performed to identify protein interactions with eNOS that putatively drive uncoupling. Mice exposed to LPS demonstrated eNOS-dependent increased alveolar permeability without evidence for altered canonical NO signaling. LPS-induced superoxide production and permeability in HLMVEC were inhibited by the NOS inhibitor nitro-l-arginine methyl ester, eNOS-targeted siRNA, the eNOS cofactor tetrahydrobiopterin, and superoxide dismutase. Co-IP indicated that LPS stimulated the association of eNOS with NADPH oxidase 2 (Nox2), which correlated with augmented eNOS S-glutathionylation both in vitro and in vivo. In vitro, Nox2-specific inhibition prevented LPS-induced eNOS modification and increases in both superoxide production and permeability. These data indicate that eNOS uncoupling contributes to superoxide production and barrier dysfunction in the lung microvasculature after exposure to LPS. Furthermore, the results implicate Nox2-mediated eNOS-S-glutathionylation as a mechanism underlying LPS-induced eNOS uncoupling in the lung microvasculature.

  5. Evolving functions of endothelial cells in inflammation.

    PubMed

    Pober, Jordan S; Sessa, William C

    2007-10-01

    Inflammation is usually analysed from the perspective of tissue-infiltrating leukocytes. Microvascular endothelial cells at a site of inflammation are both active participants in and regulators of inflammatory processes. The properties of endothelial cells change during the transition from acute to chronic inflammation and during the transition from innate to adaptive immunity. Mediators that act on endothelial cells also act on leukocytes and vice versa. Consequently, many anti-inflammatory therapies influence the behaviour of endothelial cells and vascular therapeutics influence inflammation. This Review describes the functions performed by endothelial cells at each stage of the inflammatory process, emphasizing the principal mediators and signalling pathways involved and the therapeutic implications.

  6. Methamphetamine-induced nitric oxide promotes vesicular transport in blood–brain barrier endothelial cells

    PubMed Central

    Martins, Tânia; Burgoyne, Thomas; Kenny, Bridget-Ann; Hudson, Natalie; Futter, Clare E.; Ambrósio, António F.; Silva, Ana P.; Greenwood, John; Turowski, Patric

    2013-01-01

    Methamphetamine's (METH) neurotoxicity is thought to be in part due to its ability to induce blood–brain barrier (BBB) dysfunction. Here, we investigated the effect of METH on barrier properties of cultured rat primary brain microvascular endothelial cells (BMVECs). Transendothelial flux doubled in response to METH, irrespective of the size of tracer used. At the same time, transendothelial electrical resistance was unchanged as was the ultrastructural appearance of inter-endothelial junctions and the distribution of key junction proteins, suggesting that METH promoted vesicular but not junctional transport. Indeed, METH significantly increased uptake of horseradish peroxidase into vesicular structures. METH also enhanced transendothelial migration of lymphocytes indicating that the endothelial barrier against both molecules and cells was compromised. Barrier breakdown was only observed in response to METH at low micromolar concentrations, with enhanced vesicular uptake peaking at 1 μM METH. The BMVEC response to METH also involved rapid activation of endothelial nitric oxide synthase and its inhibition abrogated METH-induced permeability and lymphocyte migration, indicating that nitric oxide was a key mediator of BBB disruption in response to METH. This study underlines the key role of nitric oxide in BBB function and describes a novel mechanism of drug-induced fluid-phase transcytosis at the BBB. PMID:22960442

  7. Methamphetamine-induced nitric oxide promotes vesicular transport in blood-brain barrier endothelial cells.

    PubMed

    Martins, Tânia; Burgoyne, Thomas; Kenny, Bridget-Ann; Hudson, Natalie; Futter, Clare E; Ambrósio, António F; Silva, Ana P; Greenwood, John; Turowski, Patric

    2013-02-01

    Methamphetamine's (METH) neurotoxicity is thought to be in part due to its ability to induce blood-brain barrier (BBB) dysfunction. Here, we investigated the effect of METH on barrier properties of cultured rat primary brain microvascular endothelial cells (BMVECs). Transendothelial flux doubled in response to METH, irrespective of the size of tracer used. At the same time, transendothelial electrical resistance was unchanged as was the ultrastructural appearance of inter-endothelial junctions and the distribution of key junction proteins, suggesting that METH promoted vesicular but not junctional transport. Indeed, METH significantly increased uptake of horseradish peroxidase into vesicular structures. METH also enhanced transendothelial migration of lymphocytes indicating that the endothelial barrier against both molecules and cells was compromised. Barrier breakdown was only observed in response to METH at low micromolar concentrations, with enhanced vesicular uptake peaking at 1 μM METH. The BMVEC response to METH also involved rapid activation of endothelial nitric oxide synthase and its inhibition abrogated METH-induced permeability and lymphocyte migration, indicating that nitric oxide was a key mediator of BBB disruption in response to METH. This study underlines the key role of nitric oxide in BBB function and describes a novel mechanism of drug-induced fluid-phase transcytosis at the BBB.

  8. TIGHT JUNCTION PROTEIN EXPRESSION AND BARRIER PROPERTIES OF IMMORTALIZED MOUSE BRAIN MICROVESSEL ENDOTHELIAL CELLS

    PubMed Central

    Brown, Rachel C.; Morris, Andrew P.; O’Neil, Roger G.

    2007-01-01

    Understanding the molecular and biochemical mechanisms regulating the blood-brain barrier is aided by in vitro model systems. Many studies have used primary cultures of brain microvessel endothelial cells for this purpose. However, primary cultures limit the generation of material for molecular and biochemical assays since cells grow slowly, are prone to contamination by other neurovascular unit cells, and lose blood-brain barrier characteristics when passaged. To address these issues, immortalized cell lines have been generated. In these studies, we assessed the suitability of the immortalized mouse brain endothelial cell line, bEnd3, as a blood-brain barrier model. RT-PCR and immunofluorescence indicated expression of multiple tight junction proteins. bEnd3 cells formed barriers to radiolabeled sucrose, and responded like primary cultures to disrupting stimuli. Exposing cells to serum-free media on their basolateral side significantly decreased paracellular permeability; astrocyte-conditioned media did not enhance barrier properties. The serum-free media-induced decrease in permeability was correlated with an increase in claudin-5 and zonula occludens-1 immunofluorescence at cell-cell contracts. We conclude that bEnd3 cells are an attractive candidate as a model of the blood-brain barrier due to their rapid growth, maintenance of blood-brain barrier characteristics over repeated passages, formation of functional barriers and amenability to numerous molecular interventions. PMID:17169347

  9. Tight junction protein expression and barrier properties of immortalized mouse brain microvessel endothelial cells.

    PubMed

    Brown, Rachel C; Morris, Andrew P; O'Neil, Roger G

    2007-01-26

    Understanding the molecular and biochemical mechanisms regulating the blood-brain barrier is aided by in vitro model systems. Many studies have used primary cultures of brain microvessel endothelial cells for this purpose. However, primary cultures limit the generation of material for molecular and biochemical assays since cells grow slowly, are prone to contamination by other neurovascular unit cells, and lose blood-brain barrier characteristics when passaged. To address these issues, immortalized cell lines have been generated. In these studies, we assessed the suitability of the immortalized mouse brain endothelial cell line, bEnd3, as a blood-brain barrier model. RT-PCR and immunofluorescence indicated expression of multiple tight junction proteins. bEnd3 cells formed barriers to radiolabeled sucrose, and responded like primary cultures to disrupting stimuli. Exposing cells to serum-free media on their basolateral side significantly decreased paracellular permeability; astrocyte-conditioned media did not enhance barrier properties. The serum-free media-induced decrease in permeability was correlated with an increase in claudin-5 and zonula occludens-1 immunofluorescence at cell-cell contracts. We conclude that bEnd3 cells are an attractive candidate as a model of the blood-brain barrier due to their rapid growth, maintenance of blood-brain barrier characteristics over repeated passages, formation of functional barriers and amenability to numerous molecular interventions.

  10. Regulation of human cerebro-microvascular endothelial baso-lateral adhesion and barrier function by S1P through dual involvement of S1P1 and S1P2 receptors.

    PubMed

    Wiltshire, Rachael; Nelson, Vicky; Kho, Dan Ting; Angel, Catherine E; O'Carroll, Simon J; Graham, E Scott

    2016-01-27

    Herein we show that S1P rapidly and acutely reduces the focal adhesion strength and barrier tightness of brain endothelial cells. xCELLigence biosensor technology was used to measure focal adhesion, which was reduced by S1P acutely and this response was mediated through both S1P1 and S1P2 receptors. S1P increased secretion of several pro-inflammatory mediators from brain endothelial cells. However, the magnitude of this response was small in comparison to that mediated by TNFα or IL-1β. Furthermore, S1P did not significantly increase cell-surface expression of any key cell adhesion molecules involved in leukocyte recruitment, included ICAM-1 and VCAM-1. Finally, we reveal that S1P acutely and dynamically regulates microvascular endothelial barrier tightness in a manner consistent with regulated rapid opening followed by closing and strengthening of the barrier. We hypothesise that the role of the S1P receptors in this process is not to cause barrier dysfunction, but is related to controlled opening of the endothelial junctions. This was revealed using real-time measurement of barrier integrity using ECIS ZΘ TEER technology and endothelial viability using xCELLigence technology. Finally, we show that these responses do not occur simply though the pharmacology of a single S1P receptor but involves coordinated action of S1P1 and S1P2 receptors.

  11. Regulation of human cerebro-microvascular endothelial baso-lateral adhesion and barrier function by S1P through dual involvement of S1P1 and S1P2 receptors

    PubMed Central

    Wiltshire, Rachael; Nelson, Vicky; Kho, Dan Ting; Angel, Catherine E.; O’Carroll, Simon J.; Graham, E. Scott

    2016-01-01

    Herein we show that S1P rapidly and acutely reduces the focal adhesion strength and barrier tightness of brain endothelial cells. xCELLigence biosensor technology was used to measure focal adhesion, which was reduced by S1P acutely and this response was mediated through both S1P1 and S1P2 receptors. S1P increased secretion of several pro-inflammatory mediators from brain endothelial cells. However, the magnitude of this response was small in comparison to that mediated by TNFα or IL-1β. Furthermore, S1P did not significantly increase cell-surface expression of any key cell adhesion molecules involved in leukocyte recruitment, included ICAM-1 and VCAM-1. Finally, we reveal that S1P acutely and dynamically regulates microvascular endothelial barrier tightness in a manner consistent with regulated rapid opening followed by closing and strengthening of the barrier. We hypothesise that the role of the S1P receptors in this process is not to cause barrier dysfunction, but is related to controlled opening of the endothelial junctions. This was revealed using real-time measurement of barrier integrity using ECIS ZΘ TEER technology and endothelial viability using xCELLigence technology. Finally, we show that these responses do not occur simply though the pharmacology of a single S1P receptor but involves coordinated action of S1P1 and S1P2 receptors. PMID:26813587

  12. Anesthetic propofol overdose causes endothelial cytotoxicity in vitro and endothelial barrier dysfunction in vivo

    SciTech Connect

    Lin, Ming-Chung; Chen, Chia-Ling; Yang, Tsan-Tzu; Choi, Pui-Ching; Hsing, Chung-Hsi; Lin, Chiou-Feng

    2012-12-01

    An overdose and a prolonged treatment of propofol may cause cellular cytotoxicity in multiple organs and tissues such as brain, heart, kidney, skeletal muscle, and immune cells; however, the underlying mechanism remains undocumented, particularly in vascular endothelial cells. Our previous studies showed that the activation of glycogen synthase kinase (GSK)-3 is pro-apoptotic in phagocytes during overdose of propofol treatment. Regarding the intravascular administration of propofol, we therefore hypothesized that propofol overdose also induces endothelial cytotoxicity via GSK-3. Propofol overdose (100 μg/ml) inhibited growth in human arterial and microvascular endothelial cells. After treatment, most of the endothelial cells experienced caspase-independent necrosis-like cell death. The activation of cathepsin D following lysosomal membrane permeabilization (LMP) determined necrosis-like cell death. Furthermore, propofol overdose also induced caspase-dependent apoptosis, at least in part. Caspase-3 was activated and acted downstream of mitochondrial transmembrane potential (MTP) loss; however, lysosomal cathepsins were not required for endothelial cell apoptosis. Notably, activation of GSK-3 was essential for propofol overdose-induced mitochondrial damage and apoptosis, but not necrosis-like cell death. Intraperitoneal administration of a propofol overdose in BALB/c mice caused an increase in peritoneal vascular permeability. These results demonstrate the cytotoxic effects of propofol overdose, including cathepsin D-regulated necrosis-like cell death and GSK-3-regulated mitochondrial apoptosis, on endothelial cells in vitro and the endothelial barrier dysfunction by propofol in vivo. Highlights: ► Propofol overdose causes apoptosis and necrosis in endothelial cells. ► Propofol overdose triggers lysosomal dysfunction independent of autophagy. ► Glycogen synthase kinase-3 facilitates propofol overdose-induced apoptosis. ► Propofol overdose causes an increase

  13. Instruction of Circulating Endothelial Progenitors In Vitro towards Specialized Blood-Brain Barrier and Arterial Phenotypes

    PubMed Central

    Ponio, Julie Boyer-Di; El-Ayoubi, Fida; Glacial, Fabienne; Ganeshamoorthy, Kayathiri; Driancourt, Catherine; Godet, Maeva; Perrière, Nicolas; Guillevic, Oriane; Couraud, Pierre Olivier; Uzan, Georges

    2014-01-01

    Objective The vascular system is adapted to specific functions in different tissues and organs. Vascular endothelial cells are important elements of this adaptation, leading to the concept of ‘specialized endothelial cells’. The phenotype of these cells is highly dependent on their specific microenvironment and when isolated and cultured, they lose their specific features after few passages, making models using such cells poorly predictive and irreproducible. We propose a new source of specialized endothelial cells based on cord blood circulating endothelial progenitors (EPCs). As prototype examples, we evaluated the capacity of EPCs to acquire properties characteristic of cerebral microvascular endothelial cells (blood-brain barrier (BBB)) or of arterial endothelial cells, in specific inducing culture conditions. Approach and Results First, we demonstrated that EPC-derived endothelial cells (EPDCs) co-cultured with astrocytes acquired several BBB phenotypic characteristics, such as restricted paracellular diffusion of hydrophilic solutes and the expression of tight junction proteins. Second, we observed that culture of the same EPDCs in a high concentration of VEGF resulted, through activation of Notch signaling, in an increase of expression of most arterial endothelial markers. Conclusions We have thus demonstrated that in vitro culture of early passage human cord blood EPDCs under specific conditions can induce phenotypic changes towards BBB or arterial phenotypes, indicating that these EPDCs maintain enough plasticity to acquire characteristics of a variety of specialized phenotypes. We propose that this property of EPDCs might be exploited for producing specialized endothelial cells in culture to be used for drug testing and predictive in vitro assays. PMID:24392113

  14. Differential role of actin in lung endothelial and epithelial barrier properties in perfused rabbit lungs.

    PubMed

    Ermert, L; Rössig, R; Hansen, T; Schütte, H; Aktories, K; Seeger, W

    1996-01-01

    Lung fluid balance is critically dependent on capillary endothelial and alveolar epithelial barrier properties, and cytoskeletal components have been implicated in these barrier functions. In an earlier study, we perfused Clostridium botulinum C2 toxin, which effects selective loss of non-muscle F-actin, through isolated rabbit lungs: a severalfold increase in the capillary filtration coefficient (Kfc) was noted, together with attenuations and disruptions of endothelial cells upon electron microscopic examination. In this model we have investigated the influence of the C2 toxin on alveolar epithelial barrier properties. Epithelial permeability was assessed by continuous monitoring of the transepithelial passage of technetium-labelled diethylenetriamine penta-acetic acid (99mTc-DTPA), offered to the alveolar surface by aerosol technique. Intravascular administration of hydrogen peroxide, used as control agent, was shown to provoke a four- to fivefold increase in the clearance rate of 99mTc-DTPA under conditions of severe fluid leakage into the lung interstitial and alveolar space. Intravascular administration of C2 toxin caused a dose- and time-dependent increase in Kfc values (8-15 fold), but the Tc-DTPA clearance rate was entirely unaffected. Moreover, transbronchial application of C2 toxin again reproduced the manifold increase in Kfc data (about six fold), but the rate of transepithelial passage of the hydrophilic Tc-DTPA complex remained unchanged. We conclude that the barrier properties of the lung microvascular endothelial and epithelial layer are differentially regulated. It is suggested that the actin microfilament system plays a decisive role in the structural and functional integrity of the endothelial but not the epithelial barrier.

  15. Novel Identity and Functional Markers for Human Corneal Endothelial Cells

    PubMed Central

    Bartakova, Alena; Alvarez-Delfin, Karen; Weisman, Alejandra D.; Salero, Enrique; Raffa, Gabriella A.; Merkhofer, Richard M.; Kunzevitzky, Noelia J.; Goldberg, Jeffrey L.

    2016-01-01

    Purpose Human corneal endothelial cell (HCEC) density decreases with age, surgical complications, or disease, leading to vision impairment. Such endothelial dysfunction is an indication for corneal transplantation, although there is a worldwide shortage of transplant-grade tissue. To overcome the current poor donor availability, here we isolate, expand, and characterize HCECs in vitro as a step toward cell therapy. Methods Human corneal endothelial cells were isolated from cadaveric corneas and expanded in vitro. Cell identity was evaluated based on morphology and immunocytochemistry, and gene expression analysis and flow cytometry were used to identify novel HCEC-specific markers. The functional ability of HCEC to form barriers was assessed by transendothelial electrical resistance (TEER) assays. Results Cultured HCECs demonstrated canonical morphology for up to four passages and later underwent endothelial-to-mesenchymal transition (EnMT). Quality of donor tissue influenced cell measures in culture including proliferation rate. Cultured HCECs expressed identity markers, and microarray analysis revealed novel endothelial-specific markers that were validated by flow cytometry. Finally, canonical HCECs expressed higher levels of CD56, which correlated with higher TEER than fibroblastic HCECs. Conclusions In vitro expansion of HCECs from cadaveric donor corneas yields functional cells identifiable by morphology and a panel of novel markers. Markers described correlated with function in culture, suggesting a basis for cell therapy for corneal endothelial dysfunction. PMID:27196322

  16. Selective HDAC6 inhibition prevents TNF-α-induced lung endothelial cell barrier disruption and endotoxin-induced pulmonary edema.

    PubMed

    Yu, Jinyan; Ma, Zhongsen; Shetty, Sreerama; Ma, Mengshi; Fu, Jian

    2016-07-01

    Lung endothelial damage contributes to the pathogenesis of acute lung injury. New strategies against lung endothelial barrier dysfunction may provide therapeutic benefits against lung vascular injury. Cell-cell junctions and microtubule cytoskeleton are basic components in maintaining endothelial barrier integrity. HDAC6, a deacetylase primarily localized in the cytoplasm, has been reported to modulate nonnuclear protein function through deacetylation. Both α-tubulin and β-catenin are substrates for HDAC6. Here, we examined the effects of tubastatin A, a highly selective HDAC6 inhibitor, on TNF-α induced lung endothelial cell barrier disruption and endotoxin-induced pulmonary edema. Selective HDAC6 inhibition by tubastatin A blocked TNF-α-induced lung endothelial cell hyperpermeability, which was associated with increased α-tubulin acetylation and microtubule stability. Tubastatin A pretreatment inhibited TNF-α-induced endothelial cell contraction and actin stress fiber formation with reduced myosin light chain phosphorylation. Selective HDAC6 inhibition by tubastatin A also induced β-catenin acetylation in human lung endothelial cells, which was associated with increased membrane localization of β-catenin and stabilization of adherens junctions. HDAC6 knockdown by small interfering RNA also prevented TNF-α-induced barrier dysfunction and increased α-tubulin and β-catenin acetylation in endothelial cells. Furthermore, in a mouse model of endotoxemia, tubastatin A was able to prevent endotoxin-induced deacetylation of α-tubulin and β-catenin in lung tissues, which was associated with reduced pulmonary edema. Collectively, our data indicate that selective HDAC6 inhibition by tubastatin A is a potent approach against lung endothelial barrier dysfunction.

  17. Effects of space mission factors on the morphology and function of endothelial cells.

    PubMed

    Kapitonova, M Yu; Kuznetsov, S L; Froemming, G R A; Muid, S; Nor-Ashikin, M N K; Otman, S; Shahir, A R M; Nawawi, H

    2013-04-01

    The structure and functions of endothelial cells after space mission were studied by electron and laser confocal microscopy, image analysis, and MTT test. The endothelial cells changed significantly (proliferative activity, size, contours, shape, distribution of mitochondria and microtubules) in comparison with controls on the Earth. These changes indicated injuries in the cytoskeleton and impairment of the barrier function of the cells, which presumably contributed to the development of endothelial dysfunction.

  18. Functional expression of a proton-coupled organic cation (H+/OC) antiporter in human brain capillary endothelial cell line hCMEC/D3, a human blood–brain barrier model

    PubMed Central

    2013-01-01

    Background Knowledge of the molecular basis and transport function of the human blood–brain barrier (BBB) is important for not only understanding human cerebral physiology, but also development of new central nervous system (CNS)-acting drugs. However, few studies have been done using human brain capillary endothelial cells, because human brain materials are difficult to obtain. The purpose of this study is to clarify the functional expression of a proton-coupled organic cation (H+/OC) antiporter in human brain capillary endothelial cell line hCMEC/D3, which has been recently developed as an in vitro human BBB model. Methods Diphenhydramine, [3H]pyrilamine and oxycodone were used as cationic drugs that proved to be H+/OC antiporter substrates. The in vitro uptake experiments by hCMEC/D3 cells were carried out under several conditions. Results Diphenhydramine and [3H]pyrilamine were both transported into hCMEC/D3 cells in a time- and concentration-dependent manner with Km values of 59 μM and 19 μM, respectively. Each inhibited uptake of the other in a competitive manner, suggesting that a common mechanism is involved in their transport. The diphenhydramine uptake was significantly inhibited by amantadine and quinidine, but not tetraethylammonium and 1-methyl-4-phenylpyridinium (substrates for well-known organic cation transporters). The uptake was inhibited by metabolic inhibitors, but was insensitive to extracellular sodium and membrane potential. Further, the uptake was increased by extracellular alkalization and intracellular acidification. These transport properties are completely consistent with those of previously characterized H+/OC antiporter in rat BBB. Conclusions The present results suggest that H+/OC antiporter is functionally expressed in hCMEC/D3 cells. PMID:23351963

  19. Netrin 1 regulates blood-brain barrier function and neuroinflammation.

    PubMed

    Podjaski, Cornelia; Alvarez, Jorge I; Bourbonniere, Lyne; Larouche, Sandra; Terouz, Simone; Bin, Jenea M; Lécuyer, Marc-André; Saint-Laurent, Olivia; Larochelle, Catherine; Darlington, Peter J; Arbour, Nathalie; Antel, Jack P; Kennedy, Timothy E; Prat, Alexandre

    2015-06-01

    Blood-brain barrier function is driven by the influence of astrocyte-secreted factors. During neuroinflammatory responses the blood-brain barrier is compromised resulting in central nervous system damage and exacerbated pathology. Here, we identified endothelial netrin 1 induction as a vascular response to astrocyte-derived sonic hedgehog that promotes autocrine barrier properties during homeostasis and increases with inflammation. Netrin 1 supports blood-brain barrier integrity by upregulating endothelial junctional protein expression, while netrin 1 knockout mice display disorganized tight junction protein expression and barrier breakdown. Upon inflammatory conditions, blood-brain barrier endothelial cells significantly upregulated netrin 1 levels in vitro and in situ, which prevented junctional breach and endothelial cell activation. Finally, netrin 1 treatment during experimental autoimmune encephalomyelitis significantly reduced blood-brain barrier disruption and decreased clinical and pathological indices of disease severity. Our results demonstrate that netrin 1 is an important regulator of blood-brain barrier maintenance that protects the central nervous system against inflammatory conditions such as multiple sclerosis and experimental autoimmune encephalomyelitis. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Irritants and Skin Barrier Function.

    PubMed

    Angelova-Fischer, Irena

    2016-01-01

    The barrier response to irritant challenge involves complex biologic events and can be modulated by various environmental, exposure and host-related factors. Irritant damage to the epidermal barrier elicits a cascade of homeostatic or pathologic responses that could be investigated by both in vitro and in vivo methods providing different information at biochemical and functional level. The present chapter summarizes the changes in key barrier function parameters following irritant exposure with focus on experimental controlled in vivo human skin studies.

  1. Hypoxia/Aglycemia-induced endothelial barrier dysfunction and tight junction protein downregulation can be ameliorated by citicoline.

    PubMed

    Ma, Xiaotang; Zhang, Huiting; Pan, Qunwen; Zhao, Yuhui; Chen, Ji; Zhao, Bin; Chen, Yanfang

    2013-01-01

    This study explores the effect of citicoline on the permeability and expression of tight junction proteins (TJPs) in endothelial cells under hypoxia/aglycemia conditions. Hypoxia or oxygen and glucose deprivation (OGD) was utilized to induce endothelial barrier breakdown model on human umbilical vein endothelial cells (HUVECs) and mouse brain microvascular endothelial cells (bEnd.3s). The effect of citicoline on endothelial barrier breakdown models was determined at either low or high concentrations. FITC-Dextran flux was used to examine the endothelial permeability. The expression of TJPs was measured by immunofluorescence, Real-time PCR and Western Blot methods. Results showed that hypoxia or OGD increased the permeability of HUVECs accompanied with down-regulation of occludens-1 (ZO-1) and occludin at both mRNA and protein levels. Similarly in bEnd.3s, hypoxia increased the permeability and decreased the expression of ZO-1 and claudin-5. Citicoline treatment dose-dependently decreased the permeability in these two models, which paralleled with elevated expression of TJPs. The data demonstrate that citicoline restores the barrier function of endothelial cells compromised by hypoxia/aglycemia probably via up-regulating the expression of TJPs.

  2. NF-κB-to-AP-1 Switch: A Mechanism Regulating Transition From Endothelial Barrier Injury to Repair in Endotoxemic Mice

    PubMed Central

    Liu, Gang; Ye, Xiaobing; Miller, Edmund J.; Liu, Shu Fang

    2014-01-01

    Endothelial barrier disruption is a hallmark of multiple organ injury (MOI). However, mechanisms governing the restoration of endothelial barrier function are poorly understood. Here, we uncovered an NF-κB-to-AP-1 switch that regulates the transition from barrier injury to repair following endotoxemic MOI. Endothelial NF-κB mediates barrier repair by inhibiting endothelial cell (EC) apoptosis. Blockade of endothelial NF-κB pathway activated the activator protein (AP)-1 pathway (NF-κB-to-AP-1 switch), which compensated for the anti-apoptotic and barrier-repair functions of NF-κB. The NF-κB-to-AP-1 switch occurred at 24 hours (injury to repair transition phase), but not at 48 hours (repair phase) post-LPS, and required an inflammatory signal within the endothelium. In the absence of an inflammatory signal, the NF-κB-to-AP-1 switch failed, resulting in enhanced EC apoptosis, augmented endothelial permeability, and impeded transition from barrier injury to recovery. The NF-κB-to-AP-1 switch is a protective mechanism to ensure timely transition from endothelial barrier injury to repair, accelerating barrier restoration following MOI. PMID:24986487

  3. Modelling the endothelial blood-CNS barriers: a method for the production of robust in vitro models of the rat blood-brain barrier and blood-spinal cord barrier

    PubMed Central

    2013-01-01

    Background Modelling the blood-CNS barriers of the brain and spinal cord in vitro continues to provide a considerable challenge for research studying the passage of large and small molecules in and out of the central nervous system, both within the context of basic biology and for pharmaceutical drug discovery. Although there has been considerable success over the previous two decades in establishing useful in vitro primary endothelial cell cultures from the blood-CNS barriers, no model fully mimics the high electrical resistance, low paracellular permeability and selective influx/efflux characteristics of the in vivo situation. Furthermore, such primary-derived cultures are typically labour-intensive and generate low yields of cells, limiting scope for experimental work. We thus aimed to establish protocols for the high yield isolation and culture of endothelial cells from both rat brain and spinal cord. Our aim was to optimise in vitro conditions for inducing phenotypic characteristics in these cells that were reminiscent of the in vivo situation, such that they developed into tight endothelial barriers suitable for performing investigative biology and permeability studies. Methods Brain and spinal cord tissue was taken from the same rats and used to specifically isolate endothelial cells to reconstitute as in vitro blood-CNS barrier models. Isolated endothelial cells were cultured to expand the cellular yield and then passaged onto cell culture inserts for further investigation. Cell culture conditions were optimised using commercially available reagents and the resulting barrier-forming endothelial monolayers were characterised by functional permeability experiments and in vitro phenotyping by immunocytochemistry and western blotting. Results Using a combination of modified handling techniques and cell culture conditions, we have established and optimised a protocol for the in vitro culture of brain and, for the first time in rat, spinal cord endothelial cells

  4. Transendothelial migration of effector T cells across inflamed endothelial barriers does not require heparan sulfate proteoglycans.

    PubMed

    Stoler-Barak, Liat; Barzilai, Sagi; Zauberman, Ayelet; Alon, Ronen

    2014-06-01

    Leukocyte diapedesis is a chemotactic multistep process that requires optimal chemoattractant presentation by the endothelial barrier. Recent studies have described a critical role for heparan sulfate glycosaminoglycans (HSGAGs) in the presentation and functions of chemokines essential for lymphocyte interactions with the lymph node vasculature. We wished to test whether HS expression by a prototypic endothelial cell type, i.e. human umbilical vein endothelial cells (HUVECs), is critical for their ability to support neutrophil and lymphocyte adhesion and transendothelial migration (TEM) under shear flow. We found that HUVECs deposit HS GAGs mainly at their basolateral compartments in both their resting and inflamed states. We next inactivated the key enzyme involved in HS biosynthesis, exostosin-1 (Ext1). Silencing Ext1 resulted in a complete loss of HS biosynthesis; nonetheless, TNF-α and IL-1β stimulation of key adhesion molecules and inflammatory chemokines necessary for neutrophil or lymphocyte adhesion and TEM remained intact. Ext1 silencing reduced neutrophil arrest and markedly impaired TEM, consistent with a role of basolateral HS GAGs in directing neutrophil crossing of inflamed endothelial barriers. Strikingly, however, the TEM of effector T cells across identically Ext1-silenced HUVECs remained normal. Importantly, the biosynthesis of the main promigratory chemokines for effector T cells and neutrophils, respectively, CCL2 and CXCL1, and their vesicle distributions were also Ext1 independent. These results suggest that transmigrating neutrophils must respond to chemokines transiently presented by apical and basolateral endothelial HS GAGs. In contrast, effector T cells can integrate chemotactic TEM signals directly from intra-endothelial chemokine stores rather than from externally deposited chemokines.

  5. Cancer cells remodel themselves and vasculature to overcome the endothelial barrier.

    PubMed

    Shenoy, Anitha K; Lu, Jianrong

    2016-10-01

    Metastasis refers to the spread of cancer cells from a primary tumor to distant organs mostly via the bloodstream. During the metastatic process, cancer cells invade blood vessels to enter circulation, and later exit the vasculature at a distant site. Endothelial cells that line blood vessels normally serve as a barrier to the movement of cells into or out of the blood. It is thus critical to understand how metastatic cancer cells overcome the endothelial barrier. Epithelial cancer cells acquire increased motility and invasiveness through epithelial-to-mesenchymal transition (EMT), which enables them to move toward vasculature. Cancer cells also express a variety of adhesion molecules that allow them to attach to vascular endothelium. Finally, cancer cells secrete or induce growth factors and cytokines to actively prompt vascular hyperpermeability that compromises endothelial barrier function and facilitates transmigration of cancer cells through the vascular wall. Elucidation of the mechanisms underlying metastatic dissemination may help develop new anti-metastasis therapeutics. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  6. Vinculin phosphorylation and barrier failure of coronary endothelial monolayers under energy depletion.

    PubMed

    Muhs, A; Noll, T; Piper, H M

    1997-08-01

    We studied the hypothesis that, in energy-depleted endothelial cells, Ca(2+)-dependent activation of protein kinase C (PKC) causes phosphorylation of vinculin and that this effect is involved in the early loss of endothelial barrier function. Vinculin localization and phosphorylation, PKC activity, and albumin permeability were studied in cultured coronary endothelial monolayers from rats. Ten minutes after the onset of metabolic inhibition by 5 mM potassium cyanide and 5 mM 2-deoxy-D-glucose, immunofluorescence of vinculin at cell-to-cell and cell-to-matrix contacts faded, whereas total cellular vinculin content remained unchanged. During the same time period, vinculin phosphorylation at tyrosine and serine sites increased by 3.9- and 3.5-fold, respectively. Vinculin phosphorylation was related to activation of PKC and an unidentified tyrosine kinase and was elicited by a rise in cytosolic Ca2+ within energy-depleted endothelial cells. Conditions inhibiting vinculin phosphorylation also reduced monolayer permeability induced by energy depletion. These data indicate that vinculin phosphorylation is involved in the progression of hyperpermeability during energy depletion in coronary endothelial monolayers.

  7. Insulin resistance and vessel endothelial function.

    PubMed Central

    van Oostrom, A J H H M; Cabezas, M Castro; Rabelink, T J

    2002-01-01

    IRS is a complex disease consisting of a clustering of metabolic disorders, of which hyperglycaemia, hyper-insulinaemia and dyslipidaemia are the most important. Endothelial dysfunction plays an important role in the pathogenesis of atherosclerosis. The effects of hyperinsulinaemia seem to depend on lipidaemia and glycaemia. Hyperglycaemia and hyperlipidaemia have detrimental effects on endothelial function in the fasting as well as the postprandial states. In both situations, the generation of ROS and vasoactive molecules plays a major role in interfering with the atheroprotective endothelium-dependent NO system. Treatment of IRS in regard to endothelial function should be focused initially on lifestyle improvement, such as stopping smoking and eating a balanced diet containing antioxidant vitamins, folic-acid, L-arginine and long-chain omega-3 unsaturated FA. Strict glucose control has shown to improve endothelial function and decrease microvascular complications. However, macrovascular complications, in line with endothelial functional improvement, have so far been reduced only when treatment was focused on other characteristics of the IRS syndrome, in particular dyslipidaemia. Other relevant treatments include ACE inhibitors and thiazolidinediones, and probably tetrahydrobiopterin and folic acid supplementation. Future studies should address the effects of therapeutic neovascularization on endothelial dysfunction. PMID:12216328

  8. Phytoestrogen Genistein Protects Against Endothelial Barrier Dysfunction in Vascular Endothelial Cells Through PKA-Mediated Suppression of RhoA Signaling

    PubMed Central

    Jia, Zhenquan; Zhen, Wei; Velayutham Anandh Babu, Pon

    2013-01-01

    The soy-derived phytoestrogen genistein has received attention for its potential to improve vascular function, but its mechanism remains unclear. Here, we report that genistein at physiologically relevant concentrations (0.1–10 μM) significantly inhibited thrombin-induced increase in endothelial monolayer permeability. Genistein also reduced the formation of stress fibers by thrombin and suppressed thrombin-induced phosphorylation of myosin light chain (MLC) on Ser19/Thr18 in endothelial cells (ECs). Genistein had no effect on resting intracellular [Ca2+] or thrombin-induced increase in Ca2+ mobilization. Addition of the inhibitors of endothelial nitric oxide synthase or estrogen receptor did not alter the protective effect of genistein. RhoA is a small GTPase that plays an important role in actin-myosin contraction and endothelial barrier dysfunction. RhoA inhibitor blocked the protective effect of genistein on endothelial permeability and also ablated thrombin-induced MLC-phosphorylation in ECs. Inhibition of PKA significantly attenuated the effect of genistein on thrombin-induced EC permeability, MLC phosphorylation, and RhoA membrane translocation in ECs. Furthermore, thrombin diminished cAMP production in ECs, which were prevented by treatment with genistein. These findings demonstrated that genistein improves thrombin-induced endothelial barrier dysfunction in ECs through PKA-mediated suppression of RhoA signaling. PMID:23254196

  9. Caveolae, Caveolins, Cavins, and Endothelial Cell Function: New Insights

    PubMed Central

    Sowa, Grzegorz

    2012-01-01

    Caveolae are cholesterol and glycosphingolipid-rich flask-shaped invaginations of the plasma membrane which are particularly abundant in vascular endothelium and present in all other cell types of the cardiovascular system, including vascular smooth-muscle cells, macrophages, cardiac myocytes, and fibroblasts. Caveolins and the more recently discovered cavins are the major protein components of caveolae. When caveolae were discovered, their functional role was believed to be limited to transport across the endothelial cell barrier. Since then, however, a large body of evidence has accumulated, suggesting that these microdomains are very important in regulating many other important endothelial cell functions, mostly due to their ability to concentrate and compartmentalize various signaling molecules. Over the course of several years, multiple studies involving knockout mouse and small interfering RNA approaches have considerably enhanced our understanding of the role of caveolae and caveolin-1 in regulating many cardiovascular functions. New findings have been reported implicating other caveolar protein components in endothelial cell signaling and function, such as the understudied caveolin-2 and newly discovered cavin proteins. The aim of this review is to focus primarily on molecular and cellular aspects of the role of caveolae, caveolins, and cavins in endothelial cell signaling and function. In addition, where appropriate, the possible implications for the cardiovascular and pulmonary physiology and pathophysiology will be discussed. PMID:22232608

  10. Myosin di-phosphorylation and peripheral actin bundle formation as initial events during endothelial barrier disruption.

    PubMed

    Hirano, Mayumi; Hirano, Katsuya

    2016-02-11

    The phosphorylation of the 20-kD myosin light chain (MLC) and actin filament formation play a key role in endothelial barrier disruption. MLC is either mono- or di-phosphorylated (pMLC and ppMLC) at T18 or S19. The present study investigated whether there are any distinct roles of pMLC and ppMLC in barrier disruption induced by thrombin. Thrombin induced a modest bi-phasic increase in pMLC and a robust mono-phasic increase in ppMLC. pMLC localized in the perinuclear cytoplasm during the initial phase, while ppMLC localized in the cell periphery, where actin bundles were formed. Later, the actin bundles were rearranged into stress fibers, where pMLC co-localized. Rho-kinase inhibitors inhibited thrombin-induced barrier disruption and peripheral localization of ppMLC and actin bundles. The double, but not single, mutation of phosphorylation sites abolished the formation of peripheral actin bundles and the barrier disruption, indicating that mono-phosphorylation of MLC at either T18 or S19 is functionally sufficient for barrier disruption. Namely, the peripheral localization, but not the degree of phosphorylation, is suggested to be essential for the functional effect of ppMLC. These results suggest that MLC phosphorylation and actin bundle formation in cell periphery are initial events during barrier disruption.

  11. 12(S)-HETE increases intracellular Ca(2+) in lymph-endothelial cells disrupting their barrier function in vitro; stabilization by clinical drugs impairing calcium supply.

    PubMed

    Nguyen, Chi Huu; Brenner, Stefan; Huttary, Nicole; Li, Yuanfang; Atanasov, Atanas Georgiev; Dirsch, Verena M; Holzner, Silvio; Stadler, Serena; Riha, Juliane; Krieger, Sigurd; Milovanovic, Danijela; Fristiohardy, Adryan; Simonitsch-Klupp, Ingrid; Dolznig, Helmut; Saiko, Philipp; Szekeres, Thomas; Giessrigl, Benedikt; Jäger, Walter; Krupitza, Georg

    2016-09-28

    Secretion of 12(S)-HETE by breast cancer emboli provokes "circular chemorepellent induced defects" (CCIDs) in the adjacent lymphatic vasculature facilitating their intravasation and lymph node metastasis which determines prognosis. Therefore, elucidating the mechanism of lymph endothelial cell (LEC) wall disintegration may provide cues for anti-metastatic intervention. The role of intracellular free Ca(2+) for CCID formation was investigated in LECs using MCF-7 or MDA-MB231 breast cancer cell spheroids in a three-dimensional cell co-culture model. 12(S)-HETE elevated the Ca(2+) level in LEC by activating PLC/IP3. Downstream, the Ca(2+)-calmodulin kinase MYLK contributed to the phosphorylation of Ser19-MLC2, LEC contraction and CCID formation. Approved clinical drugs, lidoflazine, ketotifen, epiandrosterone and cyclosporine, which reportedly disturb cellular calcium supply, inhibited 12(S)-HETE-induced Ca(2+) increase, Ser19-MLC2 phosphorylation and CCID formation. This treatment strategy may reduce spreading of breast cancer through lymphatics.

  12. Endothelial barrier dysfunction in diabetic conduit arteries: a novel method to quantify filtration

    PubMed Central

    Lu, Xiao; Huxley, Virginia H.

    2013-01-01

    The endothelial barrier plays an important role in atherosclerosis, hyperglycemia, and hypercholesterolemia. In the present study, an accurate, reproducible, and user-friendly method was used to further understand endothelial barrier function of conduit arteries. An isovolumic method was used to measure the hydraulic conductivity (Lp) of the intact vessel wall and medial-adventitial layer. Normal arterial segments with diameters from 0.2 to 5.5 mm were used to validate the method, and femoral arteries of diabetic rats were studied as an example of pathological specimens. Various arterial segments confirmed that the volume flux of water per unit surface area was linearly related to intraluminal pressure, as confirmed in microvessels. Lp of the intact wall varied from 3.5 to 22.1 × 10−7 cm·s−1·cmH2O−1 over the pressure range of 7–180 mmHg. Over the same pressure range, Lp of the endothelial barrier changed from 4.4 to 25.1 × 10−7 cm·s−1·cmH2O−1. During perfusion with albumin-free solution, Lp of rat femoral arteries increased from 6.1 to 13.2 × 10−7 cm·s−1·cmH2O−1 over the pressure range of 10–180 mmHg. Hyperglycemia increased Lp of the femoral artery in diabetic rats from 2.9 to 5.5 × 10−7 cm·s−1·cmH2O−1 over the pressure range of 20–135 mmHg. In conclusion, the Lp of a conduit artery can be accurately and reproducibly measured using a novel isovolumic method, which in diabetic rats is hyperpermeable. This is likely due to disruption of the endothelial glycocalyx. PMID:23220330

  13. Interleukin-34 Restores Blood–Brain Barrier Integrity by Upregulating Tight Junction Proteins in Endothelial Cells

    PubMed Central

    Jin, Shijie; Sonobe, Yoshifumi; Kawanokuchi, Jun; Horiuchi, Hiroshi; Cheng, Yi; Wang, Yue; Mizuno, Tetsuya; Takeuchi, Hideyuki; Suzumura, Akio

    2014-01-01

    Interleukin-34 (IL-34) is a newly discovered cytokine as an additional ligand for colony stimulating factor-1 receptor (CSF1R), and its functions are expected to overlap with colony stimulating factor-1/macrophage-colony stimulating factor. We have previously shown that the IL-34 is primarily produced by neurons in the central nervous system (CNS) and induces proliferation and neuroprotective properties of microglia which express CSF1R. However, the functions of IL-34 in the CNS are still elucidative. Here we show that CNS capillary endothelial cells also express CSF1R. IL-34 protected blood–brain barrier integrity by restored expression levels of tight junction proteins, which were downregulated by pro-inflammatory cytokines. The novel function of IL-34 on the blood–brain barrier may give us a clue for new therapeutic strategies in neuroinflammatory and neurodegenerative diseases such as multiple sclerosis and Alzheimer's disease. PMID:25535736

  14. Interleukin-34 restores blood-brain barrier integrity by upregulating tight junction proteins in endothelial cells.

    PubMed

    Jin, Shijie; Sonobe, Yoshifumi; Kawanokuchi, Jun; Horiuchi, Hiroshi; Cheng, Yi; Wang, Yue; Mizuno, Tetsuya; Takeuchi, Hideyuki; Suzumura, Akio

    2014-01-01

    Interleukin-34 (IL-34) is a newly discovered cytokine as an additional ligand for colony stimulating factor-1 receptor (CSF1R), and its functions are expected to overlap with colony stimulating factor-1/macrophage-colony stimulating factor. We have previously shown that the IL-34 is primarily produced by neurons in the central nervous system (CNS) and induces proliferation and neuroprotective properties of microglia which express CSF1R. However, the functions of IL-34 in the CNS are still elucidative. Here we show that CNS capillary endothelial cells also express CSF1R. IL-34 protected blood-brain barrier integrity by restored expression levels of tight junction proteins, which were downregulated by pro-inflammatory cytokines. The novel function of IL-34 on the blood-brain barrier may give us a clue for new therapeutic strategies in neuroinflammatory and neurodegenerative diseases such as multiple sclerosis and Alzheimer's disease.

  15. Glomerular endothelial surface layer acts as a barrier against albumin filtration.

    PubMed

    Dane, Martijn J C; van den Berg, Bernard M; Avramut, M Cristina; Faas, Frank G A; van der Vlag, Johan; Rops, Angelique L W M M; Ravelli, Raimond B G; Koster, Bram J; van Zonneveld, Anton Jan; Vink, Hans; Rabelink, Ton J

    2013-05-01

    Glomerular endothelium is highly fenestrated, and its contribution to glomerular barrier function is the subject of debate. In recent years, a polysaccharide-rich endothelial surface layer (ESL) has been postulated to act as a filtration barrier for large molecules, such as albumin. To test this hypothesis, we disturbed the ESL in C57Bl/6 mice using long-term hyaluronidase infusion for 4 weeks and monitored albumin passage using immunolabeling and correlative light-electron microscopy that allows for complete and integral assessment of glomerular albumin passage. ESL ultrastructure was visualized by transmission electron microscopy using cupromeronic blue and by localization of ESL binding lectins using confocal microscopy. We demonstrate that glomerular fenestrae are filled with dense negatively charged polysaccharide structures that are largely removed in the presence of circulating hyaluronidase, leaving the polysaccharide surfaces of other glomerular cells intact. Both retention of native ferritin [corrected] in the glomerular basement membrane and systemic blood pressure were unaltered. Enzyme treatment, however, induced albumin passage across the endothelium in 90% of glomeruli, whereas this could not be observed in controls. Yet, there was no net albuminuria due to binding and uptake of filtered albumin by the podocytes and parietal epithelium. ESL structure and function completely recovered within 4 weeks on cessation of hyaluronidase infusion. Thus, the polyanionic ESL component, hyaluronan, is a key component of the glomerular endothelial protein permeability barrier. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  16. Histamine Induces Vascular Hyperpermeability by Increasing Blood Flow and Endothelial Barrier Disruption In Vivo.

    PubMed

    Ashina, Kohei; Tsubosaka, Yoshiki; Nakamura, Tatsuro; Omori, Keisuke; Kobayashi, Koji; Hori, Masatoshi; Ozaki, Hiroshi; Murata, Takahisa

    2015-01-01

    Histamine is a mediator of allergic inflammation released mainly from mast cells. Although histamine strongly increases vascular permeability, its precise mechanism under in vivo situation remains unknown. We here attempted to reveal how histamine induces vascular hyperpermeability focusing on the key regulators of vascular permeability, blood flow and endothelial barrier. Degranulation of mast cells by antigen-stimulation or histamine treatment induced vascular hyperpermeability and tissue swelling in mouse ears. These were abolished by histamine H1 receptor antagonism. Intravital imaging showed that histamine dilated vasculature, increased blood flow, while it induced hyperpermeability in venula. Whole-mount staining showed that histamine disrupted endothelial barrier formation of venula indicated by changes in vascular endothelial cadherin (VE-cadherin) localization at endothelial cell junction. Inhibition of nitric oxide synthesis (NOS) by L-NAME or vasoconstriction by phenylephrine strongly inhibited the histamine-induced blood flow increase and hyperpermeability without changing the VE-cadherin localization. In vitro, measurements of trans-endothelial electrical resistance of human dermal microvascular endothelial cells (HDMECs) showed that histamine disrupted endothelial barrier. Inhibition of protein kinase C (PKC) or Rho-associated protein kinase (ROCK), NOS attenuated the histamine-induced barrier disruption. These observations suggested that histamine increases vascular permeability mainly by nitric oxide (NO)-dependent vascular dilation and subsequent blood flow increase and maybe partially by PKC/ROCK/NO-dependent endothelial barrier disruption.

  17. [Assessment of endothelial function in autoimmune diseases].

    PubMed

    Benhamou, Y; Bellien, J; Armengol, G; Gomez, E; Richard, V; Lévesque, H; Joannidès, R

    2014-08-01

    Numerous autoimmune-inflammatory rheumatic diseases have been associated with accelerated atherosclerosis or other types of vasculopathy leading to an increase in cardiovascular disease incidence. In addition to traditional cardiovascular risk factors, endothelial dysfunction is an important early event in the pathogenesis of atherosclerosis, contributing to plaque initiation and progression. Endothelial dysfunction is characterized by a shift of the actions of the endothelium toward reduced vasodilation, a proinflammatory and a proadhesive state, and prothrombic properties. Therefore, assessment of endothelial dysfunction targets this vascular phenotype using several biological markers as indicators of endothelial dysfunction. Measurements of soluble adhesion molecules (ICAM-1, VCAM-1, E-selectin), pro-thrombotic factors (thrombomodulin, von Willebrand factor, plasminogen activator inhibitor-1) and inflammatory cytokines are most often performed. Regarding the functional assessment of the endothelium, the flow-mediated dilatation of conduit arteries is a non-invasive method widely used in pathophysiological and interventional studies. In this review, we will briefly review the most relevant information upon endothelial dysfunction mechanisms and explorations. We will summarize the similarities and differences in the biological and functional assessments of the endothelium in different autoimmune diseases.

  18. Short-Term Effects of Low-LET Radiation on the Endothelial Barrier: Uncoupling of PECAM-1 and the Production of Endothelial Microparticles.

    PubMed

    Templin, Thomas; Sharma, Preety; Guida, Peter; Grabham, Peter

    2016-12-01

    A significant target for radiation-induced effects is the microvascular system, which is critical to healthy tissue function and its pathology is linked to disrupted endothelial barrier function. Low-linear energy transfer (LET) ionizing radiation is a source of noncancer pathologies in humans and little is known about the early events that could initiate subsequent diseases. However, it is well known that gamma radiation causes a very early disruption of the endothelial barrier at doses below those required for cytotoxic effects. After irradiation of human umbilical vein endothelial cells (HUVECs) to doses as low as 2 Gy, transendothelial electrical resistance (TEER) is transiently reduced at 3 h, and the platelet-derived endothothelial cell adhesion molecule (PECAM-1 or CD31) is uncoupled from the cells along with the release of endothelial microparticles (EMPs). In this study, we measured TEER reduction as an indicator of barrier function loss, and specifically examined the shedding of EMPs from human endothelial barrier models after a variety of low-LET irradiations, including photons and charged particles. Our findings showed two TEER responses, dependent on radiation type and environmental conditions. The first response was diminishing oscillations of TEER, which occurred during the first 10 h postirradiation. This response occurred after a 5 Gy proton or helium-ion (1 GeV/n) dose in addition to a 5 Gy gamma or X radiation dose. This occurred only in the presence of multiple growth factors and did not show a dose response, nor was it associated with EMP release. The second response was a single acute drop in TEER at 3 h after photon irradiation. Dose response was observed and was associated with the shedding of EMPs in 2D barrier cultures and in 3D vessel models. In this case, helium-ion and proton irradiations did not induce a drop in TEER or shedding of EMPs. The photon radiation effects was observed both in serum-free media and in the presence of multiple

  19. Disruption of in vitro endothelial barrier integrity by Japanese encephalitis virus-Infected astrocytes.

    PubMed

    Chang, Cheng-Yi; Li, Jian-Ri; Chen, Wen-Ying; Ou, Yen-Chuan; Lai, Ching-Yi; Hu, Yu-Hui; Wu, Chih-Cheng; Chang, Chen-Jung; Chen, Chun-Jung

    2015-05-08

    Blood-brain barrier (BBB) characteristics are induced and maintained by crosstalk between brain microvascular endothelial cells and neighboring cells. Using in vitro cell models, we previously found that a bystander effect was a cause for Japanese encephalitis-associated endothelial barrier disruption. Brain astrocytes, which neighbor BBB endothelial cells, play roles in the maintenance of BBB integrity. By extending the scope of relevant studies, a potential mechanism has been shown that the activation of neighboring astrocytes could be a cause of disruption of endothelial barrier integrity during the course of Japanese encephalitis viral (JEV) infection. JEV-infected astrocytes were found to release biologically active molecules that activated ubiquitin proteasome, degraded zonula occludens-1 (ZO-1) and claudin-5, and disrupted endothelial barrier integrity in cultured brain microvascular endothelial cells. JEV infection caused astrocytes to release vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), and matrix metalloproteinases (MMP-2/MMP-9). Our data demonstrated that VEGF and IL-6 released by JEV-infected astrocytes were critical for the proteasomal degradation of ZO-1 and the accompanying disruption of endothelial barrier integrity through the activation of Janus kinase-2 (Jak2)/signal transducer and activator of transcription-3 (STAT3) signaling as well as the induction of ubiquitin-protein ligase E3 component, n-recognin-1 (Ubr 1) in endothelial cells. MMP-induced endothelial barrier disruption was accompanied by MMP-mediated proteolytic degradation of claudin-5 and ubiquitin proteasome-mediated degradation of ZO-1 via extracellular VEGF release. Collectively, these data suggest that JEV infection could activate astrocytes and cause release of VEGF, IL-6, and MMP-2/MMP-9, thereby contributing, in a concerted action, to the induction of Japanese encephalitis-associated BBB breakdown. GLIA 2015.

  20. Junctional proteins of the blood-brain barrier: New insights into function and dysfunction

    PubMed Central

    Stamatovic, Svetlana M; Johnson, Allison M; Keep, Richard F; Andjelkovic, Anuska V

    2016-01-01

    abstract The blood-brain barrier (BBB) is a highly complex and dynamic barrier. It is formed by an interdependent network of brain capillary endothelial cells, endowed with barrier properties, and perivascular cells (astrocytes and pericytes) responsible for inducing and maintaining those properties. One of the primary properties of the BBB is a strict regulation of paracellular permeability due to the presence of junctional complexes (tight, adherens and gap junctions) between the endothelial cells. Alterations in junction assembly and function significantly affect BBB properties, particularly barrier permeability. However, such alterations are also involved in remodeling the brain endothelial cell surface and regulating brain endothelial cell phenotype. This review summarizes the characteristics of brain endothelial tight, adherens and gap junctions and highlights structural and functional alterations in junctional proteins that may contribute to BBB dysfunction. PMID:27141427

  1. Connexin channels provide a target to manipulate brain endothelial calcium dynamics and blood–brain barrier permeability

    PubMed Central

    De Bock, Marijke; Culot, Maxime; Wang, Nan; Bol, Mélissa; Decrock, Elke; De Vuyst, Elke; da Costa, Anaelle; Dauwe, Ine; Vinken, Mathieu; Simon, Alexander M; Rogiers, Vera; De Ley, Gaspard; Evans, William Howard; Bultynck, Geert; Dupont, Geneviève; Cecchelli, Romeo; Leybaert, Luc

    2011-01-01

    The cytoplasmic Ca2+ concentration ([Ca2+]i) is an important factor determining the functional state of blood–brain barrier (BBB) endothelial cells but little is known on the effect of dynamic [Ca2+]i changes on BBB function. We applied different agonists that trigger [Ca2+]i oscillations and determined the involvement of connexin channels and subsequent effects on endothelial permeability in immortalized and primary brain endothelial cells. The inflammatory peptide bradykinin (BK) triggered [Ca2+]i oscillations and increased endothelial permeability. The latter was prevented by buffering [Ca2+]i with BAPTA, indicating that [Ca2+]i oscillations are crucial in the permeability changes. Bradykinin-triggered [Ca2+]i oscillations were inhibited by interfering with connexin channels, making use of carbenoxolone, Gap27, a peptide blocker of connexin channels, and Cx37/43 knockdown. Gap27 inhibition of the oscillations was rapid (within minutes) and work with connexin hemichannel-permeable dyes indicated hemichannel opening and purinergic signaling in response to stimulation with BK. Moreover, Gap27 inhibited the BK-triggered endothelial permeability increase in in vitro and in vivo experiments. By contrast, [Ca2+]i oscillations provoked by exposure to adenosine 5′ triphosphate (ATP) were not affected by carbenoxolone or Gap27 and ATP did not disturb endothelial permeability. We conclude that interfering with endothelial connexin hemichannels is a novel approach to limiting BBB-permeability alterations. PMID:21654699

  2. Filaggrin and Skin Barrier Function.

    PubMed

    Kezic, Sanja; Jakasa, Ivone

    2016-01-01

    The skin barrier function is greatly dependent on the structure and composition of the uppermost layer of the epidermis, the stratum corneum (SC), which is made up of flattened anucleated cells surrounded by highly organized and continuous lipid matrix. The interior of the corneocytes consists mainly of keratin filaments aggregated by filaggrin (FLG) protein. Next, together with several other proteins, FLG is cross-linked into a mechanically robust cornified cell envelope providing a scaffold for the extracellular lipid matrix. In addition to its role for the SC structural and mechanical integrity, FLG degradation products account in part for the water-holding capacity and maintenance of acidic pH of the SC, both crucial for the epidermal barrier homoeostasis by regulating activity of multiple enzymes that control desquamation, lipid synthesis and inflammation. The major determinant of FLG expression in the skin are loss-of-function mutations in FLG, the strongest genetic risk factor for atopic dermatitis (AD), an inflammatory skin disease characterized by a reduced skin barrier function. The prevalence of FLG mutations varies greatly among different populations and ranges from about 10% in Northern Europeans to less than 1% in the African populations. An impaired skin barrier facilitates absorption of potentially hazardous chemicals, which might cause adverse effects in the skin, such as contact dermatitis, or systemic toxicity after their passage into blood. In another direction, a leaky epidermal barrier will lead to enhanced loss of water from the skin. A recent study has shown that even subtle increase in epidermal water loss in newborns increases the risk for AD. Although there are multiple modes of action by which FLG might affect skin barrier it is still unclear whether and how FLG deficiency leads to the reduced skin barrier function. This chapter summarizes the current knowledge in this field obtained from clinical studies, and animal and in vitro models

  3. Dietary phosphorus acutely impairs endothelial function.

    PubMed

    Shuto, Emi; Taketani, Yutaka; Tanaka, Rieko; Harada, Nagakatsu; Isshiki, Masashi; Sato, Minako; Nashiki, Kunitaka; Amo, Kikuko; Yamamoto, Hironori; Higashi, Yukihito; Nakaya, Yutaka; Takeda, Eiji

    2009-07-01

    Excessive dietary phosphorus may increase cardiovascular risk in healthy individuals as well as in patients with chronic kidney disease, but the mechanisms underlying this risk are not completely understood. To determine whether postprandial hyperphosphatemia may promote endothelial dysfunction, we investigated the acute effect of phosphorus loading on endothelial function in vitro and in vivo. Exposing bovine aortic endothelial cells to a phosphorus load increased production of reactive oxygen species, which depended on phosphorus influx via sodium-dependent phosphate transporters, and decreased nitric oxide production via inhibitory phosphorylation of endothelial nitric oxide synthase. Phosphorus loading inhibited endothelium-dependent vasodilation of rat aortic rings. In 11 healthy men, we alternately served meals containing 400 mg or 1200 mg of phosphorus in a double-blind crossover study and measured flow-mediated dilation of the brachial artery before and 2 h after the meals. The high dietary phosphorus load increased serum phosphorus at 2 h and significantly decreased flow-mediated dilation. Flow-mediated dilation correlated inversely with serum phosphorus. Taken together, these findings suggest that endothelial dysfunction mediated by acute postprandial hyperphosphatemia may contribute to the relationship between serum phosphorus level and the risk for cardiovascular morbidity and mortality.

  4. Dietary Phosphorus Acutely Impairs Endothelial Function

    PubMed Central

    Shuto, Emi; Taketani, Yutaka; Tanaka, Rieko; Harada, Nagakatsu; Isshiki, Masashi; Sato, Minako; Nashiki, Kunitaka; Amo, Kikuko; Yamamoto, Hironori; Higashi, Yukihito; Nakaya, Yutaka; Takeda, Eiji

    2009-01-01

    Excessive dietary phosphorus may increase cardiovascular risk in healthy individuals as well as in patients with chronic kidney disease, but the mechanisms underlying this risk are not completely understood. To determine whether postprandial hyperphosphatemia may promote endothelial dysfunction, we investigated the acute effect of phosphorus loading on endothelial function in vitro and in vivo. Exposing bovine aortic endothelial cells to a phosphorus load increased production of reactive oxygen species, which depended on phosphorus influx via sodium-dependent phosphate transporters, and decreased nitric oxide production via inhibitory phosphorylation of endothelial nitric oxide synthase. Phosphorus loading inhibited endothelium-dependent vasodilation of rat aortic rings. In 11 healthy men, we alternately served meals containing 400 mg or 1200 mg of phosphorus in a double-blind crossover study and measured flow-mediated dilation of the brachial artery before and 2 h after the meals. The high dietary phosphorus load increased serum phosphorus at 2 h and significantly decreased flow-mediated dilation. Flow-mediated dilation correlated inversely with serum phosphorus. Taken together, these findings suggest that endothelial dysfunction mediated by acute postprandial hyperphosphatemia may contribute to the relationship between serum phosphorus level and the risk for cardiovascular morbidity and mortality. PMID:19406976

  5. The EP1/EP3 receptor agonist 17-pt-PGE2 acts as an EP4 receptor agonist on endothelial barrier function and in a model of LPS-induced pulmonary inflammation.

    PubMed

    Theiler, Anna; Konya, Viktoria; Pasterk, Lisa; Maric, Jovana; Bärnthaler, Thomas; Lanz, Ilse; Platzer, Wolfgang; Schuligoi, Rufina; Heinemann, Akos

    2016-12-01

    Endothelial dysfunction is a hallmark of inflammatory conditions. We recently demonstrated that prostaglandin (PG)E2 enhances the resistance of pulmonary endothelium in vitro and counteracts lipopolysaccharide (LPS)-induced pulmonary inflammation in vivo via EP4 receptors. The aim of this study was to investigate the role of the EP1/EP3 receptor agonist 17-phenyl-trinor-(pt)-PGE2 on acute lung inflammation in a mouse model. In LPS-induced pulmonary inflammation in mice, 17-pt-PGE2 reduced neutrophil infiltration and inhibited vascular leakage. These effects were unaltered by an EP1 antagonist, but reversed by EP4 receptor antagonists. 17-pt-PGE2 increased the resistance of pulmonary microvascular endothelial cells and prevented thrombin-induced disruption of endothelial junctions. Again, these effects were not mediated via EP1 or EP3 but through activation of the EP4 receptor, as demonstrated by the lack of effect of more selective EP1 and EP3 receptor agonists, prevention of these effects by EP4 antagonists and EP4 receptor knock-down by siRNA. In contrast, the aggregation enhancing effect of 17-pt-PGE2 in human platelets was mediated via EP3 receptors. Our results demonstrate that 17-pt-PGE2 enhances the endothelial barrier in vitro on pulmonary microvascular endothelial cells, and accordingly ameliorates the recruitment of neutrophils, via EP4 receptors in vivo. This suggests a beneficial effect of 17-pt-PGE2 on pulmonary inflammatory diseases. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Clinically important factors influencing endothelial function.

    PubMed

    Vapaatalo, H; Mervaala, E

    2001-01-01

    The endothelium, a continuous cellular monolayer lining the blood vessels, has an enormous range of important homeostatic roles. It serves and participates in highly active metabolic and regulatory functions including control of primary hemostasis, blood coagulation and fibrinolysis, platelet and leukocyte interactions with the vessel wall, interaction with lipoprotein metabolism, presentation of histocompatibility antigens, regulation of vascular tone and growth and further of blood pressure. Many crucial vasoactive endogenous compounds like prostacyclin, thromboxane, nitric oxide, endothelin, angiotensin, endothelium derived hyperpolarizing factor, free radicals and bradykinin are formed in the endothelial cells to control the functions of vascular smooth muscle cells and of circulating blood cells. These versatile and complex systems and cellular interactions are extremely vulnerable. The balances may be disturbed by numerous endogenous and exogenous factors including psychological and physical stress, disease states characterized by vasospasm, inflammation, leukocyte and platelet adhesion and aggregation, thrombosis, abnormal vascular proliferation, atherosclerosis and hypertension. The endothelial cells are also the site of action of many drugs and exogenous toxic substances (e.g. smoking, alcohol). As markers and assays for endothelial dysfunction, direct measurement of nitric oxide, its metabolites from plasma and urine, functional measurement of vascular nitric oxide dependent responses and assay of different circulating markers have been used. In numerous pathological conditions (e.g. atherosclerosis, hypertension, congestive heart failure, hyperhomocysteinemia, diabetes, renal failure, transplantation, liver cirrhosis) endothelial dysfunction has been described to exist. Some of them, as well as hormonal and nutritional factors and drug treatment will be discussed in this short review.

  7. Immortalized endothelial cell lines for in vitro blood-brain barrier models: A systematic review.

    PubMed

    Rahman, Nurul Adhwa; Rasil, Alifah Nur'ain Haji Mat; Meyding-Lamade, Uta; Craemer, Eva Maria; Diah, Suwarni; Tuah, Ani Afiqah; Muharram, Siti Hanna

    2016-07-01

    Endothelial cells play the most important role in construction of the blood-brain barrier. Many studies have opted to use commercially available, easily transfected or immortalized endothelial cell lines as in vitro blood-brain barrier models. Numerous endothelial cell lines are available, but we do not currently have strong evidence for which cell lines are optimal for establishment of such models. This review aimed to investigate the application of immortalized endothelial cell lines as in vitro blood-brain barrier models. The databases used for this review were PubMed, OVID MEDLINE, ProQuest, ScienceDirect, and SpringerLink. A narrative systematic review was conducted and identified 155 studies. As a result, 36 immortalized endothelial cell lines of human, mouse, rat, porcine and bovine origins were found for the establishment of in vitro blood-brain barrier and brain endothelium models. This review provides a summary of immortalized endothelial cell lines as a guideline for future studies and improvements in the establishment of in vitro blood-brain barrier models. It is important to establish a good and reproducible model that has the potential for multiple applications, in particular a model of such a complex compartment such as the blood-brain barrier. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Bicarbonate disruption of the pulmonary endothelial barrier via activation of endogenous soluble adenylyl cyclase, isoform 10

    PubMed Central

    Obiako, Boniface; Calchary, Wendy; Xu, Ningyong; Kunstadt, Ryan; Richardson, Bianca; Nix, Jessica

    2013-01-01

    It is becoming increasingly apparent that cAMP signals within the pulmonary endothelium are highly compartmentalized, and this compartmentalization is critical to maintaining endothelial barrier integrity. Studies demonstrate that the exogenous soluble bacterial toxin, ExoY, and heterologous expression of the forskolin-stimulated soluble mammalian adenylyl cyclase (AC) chimera, sACI/II, elevate cytosolic cAMP and disrupt the pulmonary microvascular endothelial barrier. The barrier-disruptive effects of cytosolic cAMP generated by exogenous soluble ACs are in contrast to the barrier-protective effects of subplasma membrane cAMP generated by transmembrane AC, which strengthens endothelial barrier integrity. Endogenous soluble AC isoform 10 (AC10 or commonly known as sAC) lacks transmembrane domains and localizes within the cytosolic compartment. AC10 is uniquely activated by bicarbonate to generate cytosolic cAMP, yet its role in regulation of endothelial barrier integrity has not been addressed. Here we demonstrate that, within the pulmonary circulation, AC10 is expressed in pulmonary microvascular endothelial cells (PMVECs) and pulmonary artery endothelial cells (PAECs), yet expression in PAECs is lower. Furthermore, pulmonary endothelial cells selectively express bicarbonate cotransporters. While extracellular bicarbonate generates a phosphodiesterase 4-sensitive cAMP pool in PMVECs, no such cAMP response is detected in PAECs. Finally, addition of extracellular bicarbonate decreases resistance across the PMVEC monolayer and increases the filtration coefficient in the isolated perfused lung above osmolality controls. Collectively, these findings suggest that PMVECs have a bicarbonate-sensitive cytosolic cAMP pool that disrupts endothelial barrier integrity. These studies could provide an alternative mechanism for the controversial effects of bicarbonate correction of acidosis of acute respiratory distress syndrome patients. PMID:23686854

  9. Activation of RhoA, but Not Rac1, Mediates Early Stages of S1P-Induced Endothelial Barrier Enhancement.

    PubMed

    Zhang, Xun E; Adderley, Shaquria P; Breslin, Jerome W

    2016-01-01

    Compromised endothelial barrier function is a hallmark of inflammation. Rho family GTPases are critical in regulating endothelial barrier function, yet their precise roles, particularly in sphingosine-1-phosphate (S1P)-induced endothelial barrier enhancement, remain elusive. Confluent cultures of human umbilical vein endothelial cells (HUVEC) or human dermal microvascular endothelial cells (HDMEC) were used to model the endothelial barrier. Barrier function was assessed by determining the transendothelial electrical resistance (TER) using an electrical cell-substrate impedance sensor (ECIS). The roles of Rac1 and RhoA were tested in S1P-induced barrier enhancement. The results show that pharmacologic inhibition of Rac1 with Z62954982 failed to block S1P-induced barrier enhancement. Likewise, expression of a dominant negative form of Rac1, or knockdown of native Rac1 with siRNA, failed to block S1P-induced elevations in TER. In contrast, blockade of RhoA with the combination of the inhibitors Rhosin and Y16 significantly reduced S1P-induced increases in TER. Assessment of RhoA activation in real time using a fluorescence resonance energy transfer (FRET) biosensor showed that S1P increased RhoA activation primarily at the edges of cells, near junctions. This was complemented by myosin light chain-2 phosphorylation at cell edges, and increased F-actin and vinculin near intercellular junctions, which could all be blocked with pharmacologic inhibition of RhoA. The results suggest that S1P causes activation of RhoA at the cell periphery, stimulating local activation of the actin cytoskeleton and focal adhesions, and resulting in endothelial barrier enhancement. S1P-induced Rac1 activation, however, does not appear to have a significant role in this process.

  10. Rab5-mediated VE-cadherin internalization regulates the barrier function of the lung microvascular endothelium

    PubMed Central

    Yang, Junjun; Yao, Wei; Qian, Guisheng; Wei, Zhenghua

    2016-01-01

    The small GTPase Rab5 has been well defined to control the vesicle-mediated plasma membrane protein transport to the endosomal compartment. However, its function in the internalization of vascular endothelial (VE)-cadherin, an important component of adherens junctions, and as a result regulating the endothelial cell polarity and barrier function remain unknown. Here, we demonstrated that lipopolysaccharide (LPS) simulation markedly enhanced the activation and expression of Rab5 in human pulmonary microvascular endothelial cells (HPMECs), which is accompanied by VE-cadherin internalization. In parallel, LPS challenge also induced abnormal cell polarity and dysfunction of the endothelial barrier in HPMECs. LPS stimulation promoted the translocation of VE-cadherin from the plasma membrane to intracellular compartments, and intracellularly expressed VE-cadherin was extensively colocalized with Rab5. Small interfering RNA (siRNA)-mediated depletion of Rab5a expression attenuated the disruption of LPS-induced internalization of VE-cadherin and the disorder of cell polarity. Furthermore, knockdown of Rab5 inhibited the vascular endothelial hyperpermeability and protected endothelial barrier function from LPS injury, both in vitro and in vivo. These results suggest that Rab5 is a critical mediator of LPS-induced endothelial barrier dysfunction, which is likely mediated through regulating VE-cadherin internalization. These findings provide evidence, implicating that Rab5a is a potential therapeutic target for preventing endothelial barrier disruption and vascular inflammation. PMID:26112597

  11. Rab5-mediated VE-cadherin internalization regulates the barrier function of the lung microvascular endothelium.

    PubMed

    Yang, Junjun; Yao, Wei; Qian, Guisheng; Wei, Zhenghua; Wu, Guangyu; Wang, Guansong

    2015-12-01

    The small GTPase Rab5 has been well defined to control the vesicle-mediated plasma membrane protein transport to the endosomal compartment. However, its function in the internalization of vascular endothelial (VE)-cadherin, an important component of adherens junctions, and as a result regulating the endothelial cell polarity and barrier function remain unknown. Here, we demonstrated that lipopolysaccharide (LPS) simulation markedly enhanced the activation and expression of Rab5 in human pulmonary microvascular endothelial cells (HPMECs), which is accompanied by VE-cadherin internalization. In parallel, LPS challenge also induced abnormal cell polarity and dysfunction of the endothelial barrier in HPMECs. LPS stimulation promoted the translocation of VE-cadherin from the plasma membrane to intracellular compartments, and intracellularly expressed VE-cadherin was extensively colocalized with Rab5. Small interfering RNA (siRNA)-mediated depletion of Rab5a expression attenuated the disruption of LPS-induced internalization of VE-cadherin and the disorder of cell polarity. Furthermore, knockdown of Rab5 inhibited the vascular endothelial hyperpermeability and protected endothelial barrier function from LPS injury, both in vitro and in vivo. These results suggest that Rab5 is a critical mediator of LPS-induced endothelial barrier dysfunction, which is likely mediated through regulating VE-cadherin internalization. These findings provide evidence, implicating that Rab5a is a potential therapeutic target for preventing endothelial barrier disruption and vascular inflammation.

  12. Endothelial cells use dynamic actin to facilitate lymphocyte transendothelial migration and maintain the monolayer barrier.

    PubMed

    Mooren, Olivia L; Li, Jinmei; Nawas, Julie; Cooper, John A

    2014-12-15

    The vascular endothelium is a highly dynamic structure, and the integrity of its barrier function is tightly regulated. Normally impenetrable to cells, the endothelium actively assists lymphocytes to exit the bloodstream during inflammation. The actin cytoskeleton of the endothelial cell (EC) is known to facilitate transmigration, but the cellular and molecular mechanisms are not well understood. Here we report that actin assembly in the EC, induced by Arp2/3 complex under control of WAVE2, is important for several steps in the process of transmigration. To begin transmigration, ECs deploy actin-based membrane protrusions that create a cup-shaped docking structure for the lymphocyte. We found that docking structure formation involves the localization and activation of Arp2/3 complex by WAVE2. The next step in transmigration is creation of a migratory pore, and we found that endothelial WAVE2 is needed for lymphocytes to follow a transcellular route through an EC. Later, ECs use actin-based protrusions to close the gap behind the lymphocyte, which we discovered is also driven by WAVE2. Finally, we found that ECs in resting endothelial monolayers use lamellipodial protrusions dependent on WAVE2 to form and maintain contacts and junctions between cells.

  13. Arterial endothelial function measurement method and apparatus

    DOEpatents

    Maltz, Jonathan S; Budinger, Thomas F

    2014-03-04

    A "relaxoscope" (100) detects the degree of arterial endothelial function. Impairment of arterial endothelial function is an early event in atherosclerosis and correlates with the major risk factors for cardiovascular disease. An artery (115), such as the brachial artery (BA) is measured for diameter before and after several minutes of either vasoconstriction or vasorelaxation. The change in arterial diameter is a measure of flow-mediated vasomodification (FMVM). The relaxoscope induces an artificial pulse (128) at a superficial radial artery (115) via a linear actuator (120). An ultrasonic Doppler stethoscope (130) detects this pulse 10-20 cm proximal to the point of pulse induction (125). The delay between pulse application and detection provides the pulse transit time (PTT). By measuring PTT before (160) and after arterial diameter change (170), FMVM may be measured based on the changes in PTT caused by changes in vessel caliber, smooth muscle tone and wall thickness.

  14. CD36 and Fyn kinase mediate malaria-induced lung endothelial barrier dysfunction in mice infected with Plasmodium berghei.

    PubMed

    Anidi, Ifeanyi U; Servinsky, Laura E; Rentsendorj, Otgonchimeg; Stephens, R Scott; Scott, Alan L; Pearse, David B

    2013-01-01

    Severe malaria can trigger acute lung injury characterized by pulmonary edema resulting from increased endothelial permeability. However, the mechanism through which lung fluid conductance is altered during malaria remains unclear. To define the role that the scavenger receptor CD36 may play in mediating this response, C57BL/6J (WT) and CD36-/- mice were infected with P. berghei ANKA and monitored for changes in pulmonary endothelial barrier function employing an isolated perfused lung system. WT lungs demonstrated a >10-fold increase in two measures of paracellular fluid conductance and a decrease in the albumin reflection coefficient (σalb) compared to control lungs indicating a loss of barrier function. In contrast, malaria-infected CD36-/- mice had near normal fluid conductance but a similar reduction in σalb. In WT mice, lung sequestered iRBCs demonstrated production of reactive oxygen species (ROS). To determine whether knockout of CD36 could protect against ROS-induced endothelial barrier dysfunction, mouse lung microvascular endothelial monolayers (MLMVEC) from WT and CD36-/- mice were exposed to H2O2. Unlike WT monolayers, which showed dose-dependent decreases in transendothelial electrical resistance (TER) from H2O2 indicating loss of barrier function, CD36-/- MLMVEC demonstrated dose-dependent increases in TER. The differences between responses in WT and CD36-/- endothelial cells correlated with important differences in the intracellular compartmentalization of the CD36-associated Fyn kinase. Malaria infection increased total lung Fyn levels in CD36-/- lungs compared to WT, but this increase was due to elevated production of the inactive form of Fyn further suggesting a dysregulation of Fyn-mediated signaling. The importance of Fyn in CD36-dependent endothelial signaling was confirmed using in vitro Fyn knockdown as well as Fyn-/- mice, which were also protected from H2O2- and malaria-induced lung endothelial leak, respectively. Our results demonstrate

  15. Plasmodium falciparum Histidine-Rich Protein II Compromises Brain Endothelial Barriers and May Promote Cerebral Malaria Pathogenesis.

    PubMed

    Pal, Priya; Daniels, Brian P; Oskman, Anna; Diamond, Michael S; Klein, Robyn S; Goldberg, Daniel E

    2016-06-07

    Cerebral malaria (CM) is a disease of the vascular endothelium caused by Plasmodium falciparum It is characterized by parasite sequestration, inflammatory cytokine production, and vascular leakage. A distinguishing feature of P. falciparum infection is parasite production and secretion of histidine-rich protein II (HRPII). Plasma HRPII is a diagnostic and prognostic marker for falciparum malaria. We demonstrate that disruption of a human cerebral microvascular endothelial barrier by P. falciparum-infected erythrocytes depends on expression of HRPII. Purified recombinant or native HRPII can recapitulate these effects. HRPII action occurs via activation of the inflammasome, resulting in decreased integrity of tight junctions and increased endothelial permeability. We propose that HRPII is a virulence factor that may contribute to cerebral malaria by compromising endothelial barrier integrity within the central nervous system. Cerebral malaria is a devastating disease. Patients have high levels of the protein HRPII in their blood. We have found that endothelial cell barriers become leaky when treated with concentrations of HRPII similar to those found in patients. This result suggests that HRPII may be important in cerebral malaria. Our finding that HRPII functions by causing inflammation suggests points of intervention for therapy or vaccination against this disease. Copyright © 2016 Pal et al.

  16. Molecular Mechanisms in Compromised Endothelial Barrier during Breast Cancer Metastasis

    DTIC Science & Technology

    2008-03-01

    diapedesis . We proposed to examine these transient and localized signaling events using a three dimensional (3D) assay with superior spatio-temporal...reports have documented the phenomenon of transcellular diapedesis by leukocytes through the endothelial layer over the years, the actual transcellular...the surface of the endothelial cell [9]. However, the actual process of diapedesis of the tumor cell triggered a marked regional activation of MLCK

  17. Helminths and intestinal barrier function.

    PubMed

    McKay, Derek M; Shute, Adam; Lopes, Fernando

    2017-01-02

    Approximately one-sixth of the worlds' population is infected with helminths and this class of parasite takes a major toll on domestic livestock. The majority of species of parasitic helminth that infect mammals live in the gut (the only niche for tapeworms) where they contact the hosts' epithelial cells. Here, the helminth-intestinal epithelial interface is reviewed in terms of the impact on, and regulation of epithelial barrier function, both intrinsic (epithelial permeability) and extrinsic (mucin, bacterial peptides, commensal bacteria) elements of the barrier. The data available on direct effects of helminths on epithelial permeability are scant, fragmentary and pales in comparison with knowledge of mobilization of immune reactions and effector cells in response to helminth parasites and how these impact intestinal barrier function. The interaction of helminth-host and helminth-host-bacteria is an important determinant of gut form and function and precisely defining these interactions will radically alter our understanding of normal gut physiology and pathophysiological reactions, revealing new approaches to infection with parasitic helminths, bacterial pathogens and idiopathic auto-inflammatory disease.

  18. Intracellular ascorbate tightens the endothelial permeability barrier through Epac1 and the tubulin cytoskeleton.

    PubMed

    Parker, William H; Rhea, Elizabeth Meredith; Qu, Zhi-Chao; Hecker, Morgan R; May, James M

    2016-10-01

    Vitamin C, or ascorbic acid, both tightens the endothelial permeability barrier in basal cells and also prevents barrier leak induced by inflammatory agents. Barrier tightening by ascorbate in basal endothelial cells requires nitric oxide derived from activation of nitric oxide synthase. Although ascorbate did not affect cyclic AMP levels in our previous study, there remains a question of whether it might activate downstream cyclic AMP-dependent pathways. In this work, we found in both primary and immortalized cultured endothelial cells that ascorbate tightened the endothelial permeability barrier by ∼30%. In human umbilical vein endothelial cells, this occurred at what are likely physiologic intracellular ascorbate concentrations. In so doing, ascorbate decreased measures of oxidative stress and also flattened the cells to increase cell-to-cell contact. Inhibition of downstream cyclic AMP-dependent proteins via protein kinase A did not prevent ascorbate from tightening the endothelial permeability barrier, whereas inhibition of Epac1 did block the ascorbate effect. Although Epac1 was required, its mediator Rap1 was not activated. Furthermore, ascorbate acutely stabilized microtubules during depolymerization induced by colchicine and nocodazole. Over several days in culture, ascorbate also increased the amount of stable acetylated α-tubulin. Microtubule stabilization was further suggested by the finding that ascorbate increased the amount of Epac1 bound to α-tubulin. These results suggest that physiologic ascorbate concentrations tighten the endothelial permeability barrier in unstimulated cells by stabilizing microtubules in a manner downstream of cyclic AMP that might be due both to increasing nitric oxide availability and to scavenging of reactive oxygen or nitrogen species.

  19. Glutamine and intestinal barrier function.

    PubMed

    Wang, Bin; Wu, Guoyao; Zhou, Zhigang; Dai, Zhaolai; Sun, Yuli; Ji, Yun; Li, Wei; Wang, Weiwei; Liu, Chuang; Han, Feng; Wu, Zhenlong

    2015-10-01

    The intestinal barrier integrity is essential for the absorption of nutrients and health in humans and animals. Dysfunction of the mucosal barrier is associated with increased gut permeability and development of multiple gastrointestinal diseases. Recent studies highlighted a critical role for glutamine, which had been traditionally considered as a nutritionally non-essential amino acid, in activating the mammalian target of rapamycin cell signaling in enterocytes. In addition, glutamine has been reported to enhance intestinal and whole-body growth, to promote enterocyte proliferation and survival, and to regulate intestinal barrier function in injury, infection, weaning stress, and other catabolic conditions. Mechanistically, these effects were mediated by maintaining the intracellular redox status and regulating expression of genes associated with various signaling pathways. Furthermore, glutamine stimulates growth of the small intestinal mucosa in young animals and also enhances ion transport by the gut in neonates and adults. Growing evidence supports the notion that glutamine is a nutritionally essential amino acid for neonates and a conditionally essential amino acid for adults. Thus, as a functional amino acid with multiple key physiological roles, glutamine holds great promise in protecting the gut from atrophy and injury under various stress conditions in mammals and other animals.

  20. Skin Barrier Function and Allergens.

    PubMed

    Engebretsen, Kristiane Aasen; Thyssen, Jacob Pontoppidan

    2016-01-01

    The skin is an important barrier protecting us from mechanical insults, microorganisms, chemicals and allergens, but, importantly, also reducing water loss. A common hallmark for many dermatoses is a compromised skin barrier function, and one could suspect an elevated risk of contact sensitization (CS) and allergy following increased penetration of potential allergens. However, the relationship between common dermatoses such as psoriasis, atopic dermatitis (AD) and irritant contact dermatitis (ICD) and the development of contact allergy (CA) is complex, and depends on immunologic responses and skin barrier status. Psoriasis has traditionally been regarded a Th1-dominated disease, but the discovery of Th17 cells and IL-17 provides new and interesting information regarding the pathogenesis of the disease. Research suggests an inverse relationship between psoriasis and CA, possibly due to increased levels of Th17 cells and its associated cytokines. As for AD, a positive association to CS has been established in epidemiological studies, but is still unresolved. Experimental studies show, however, an inverse relationship between AD and CS. The opposing and antagonistic influences of Th1 (CS) and Th2 (AD) have been proposed as an explanation. Finally, there is convincing evidence that exposure to irritants increases the risk of CS, and patients with ICD are, therefore, at great risk of developing CA. Skin irritation leads to the release of IL-1 and TNF-α, which affects the function of antigen-presenting cells and promotes their migration to local lymph nodes, thus increasing the probability of CS and ultimately the development of CA.

  1. Arterial endothelial barrier dysfunction: actions of homocysteine and the hypoxanthine-xanthine oxidase free radical generating system.

    PubMed

    Berman, R S; Martin, W

    1993-04-01

    1. Endothelial barrier function was assessed by use of an in vitro model in which transfer of trypan blue-labelled albumin was measured across monolayers of bovine aortic endothelial cells grown on polycarbonate membranes. 2. Addition of either hypoxanthine (0.2 mM) or xanthine oxidase (20 mu ml-1) alone during a 90 min incubation did not affect albumin transfer across endothelial cell monolayers, but a combination of both increased transfer. 3. The increase in albumin transfer induced by hypoxanthine and xanthine oxidase was abolished by catalase (3 u ml-1), reduced by allopurinol (4 mM), but unaffected by superoxide dismutase (6000 u ml-1), the hydroxyl radical scavengers, mannitol (15 mM), dimethylthiourea (10 mM) and N-(2-mercaptopropionyl)-glycine (1 mM), the iron chelator, deferoxamine (0.5 mM), ferric chloride (50 microM), an inhibitor of nitric oxide synthase, NG-nitro-L-arginine (30 microM), or the antioxidant, dithiothreitol (3 mM). 4. Hydrogen peroxide (0.1-30 mM) itself increased albumin transfer across endothelial cell monolayers, exhibiting a biphasic concentration-response curve. The increase induced by 0.1 mM hydrogen peroxide was abolished in the presence of 0.3 u ml-1 catalase whilst that induced by 10 mM hydrogen peroxide was abolished by 3000 u ml-1 catalase. 5. Homocysteine (0.5-1.5 mM) did not affect albumin transfer across endothelial monolayers when added alone, but when added in combination with copper sulphate (50 microM), which catalyses its oxidation, a significant increase in albumin transfer was observed. 6. The increase in albumin transfer induced by the combination of homocysteine (1.5 mM) and copper sulphate was abolished by catalase (1 u ml-1), but was unaffected by superoxide dismutase (6000 u ml-1), mannitol (15 mM), dimethylthiourea (1 mM) or deferoxamine (0.5 mM).7. The data suggest that the endothelial barrier dysfunction induced by the combination of hypoxanthine and xanthine oxidase is mediated solely by the action of

  2. Neurothelin: an inducible cell surface glycoprotein of blood-brain barrier-specific endothelial cells and distinct neurons

    PubMed Central

    1990-01-01

    The blood-brain barrier is characterized by still poorly understood barrier and transport functions performed by specialized endothelial cells. Hybridoma technology has been used to identify a protein termed neurothelin that is specific for these endothelial cells. Neurothelin is defined by the species-specific mouse mAb 1W5 raised against lentil- lectin-binding proteins of neural tissue from embryonic chick. In the posthatch chick, neurothelin expression is found on endothelial cells within the brain but not on those of the systemic vascular system. Injection of the monoclonal antibody in vivo leads to labeling of brain capillaries, indicating that the corresponding antigen is expressed on the luminal surface of brain endothelial cells. Transplantation of embryonic mouse brain onto the chick chorioallantoic membrane results in rodent brain vascularization by the avian vascular system. Subsequently, normally mAb 1W5-negative endothelial cells, originating from blood vessels of the chick chorioallantoic membrane, are induced to express neurothelin when they are in contact with mouse neural tissue. In contrast to differentiated brain neurons that do not express neurothelin, neurons of the nonvascularized chick retina synthesize neurothelin. However, neurothelin is not found on retinal ganglion cell axons terminating on 1W5-negative brain cells. 1W5 immunoreactivity was also found in the pigment epithelium that forms the blood-eye barrier. Putting epithelial cells into culture results in concentration of neurothelin at cell-cell contact sites, leaving other cell surface areas devoid of antigen. Therefore, the distribution of neurothelin appears to be regulated by cell-cell interactions. In Western blot analysis, neurothelin was identified as a protein with a molecular mass of approximately 43 kD. The protein bears at least one intramolecular disulfide bridge and sulfated glucuronic acid as well as alpha-D- substituted mannose/glucose moieties. The exclusive

  3. Histamine activates p38 MAP kinase and alters local lamellipodia dynamics, reducing endothelial barrier integrity and eliciting central movement of actin fibers.

    PubMed

    Adderley, Shaquria P; Lawrence, Curtis; Madonia, Eyong; Olubadewo, Joseph O; Breslin, Jerome W

    2015-07-01

    The role of the actin cytoskeleton in endothelial barrier function has been debated for nearly four decades. Our previous investigation revealed spontaneous local lamellipodia in confluent endothelial monolayers that appear to increase overlap at intercellular junctions. We tested the hypothesis that the barrier-disrupting agent histamine would reduce local lamellipodia protrusions and investigated the potential involvement of p38 mitogen-activated protein (MAP) kinase activation and actin stress fiber formation. Confluent monolayers of human umbilical vein endothelial cells (HUVEC) expressing green fluorescent protein-actin were studied using time-lapse fluorescence microscopy. The protrusion and withdrawal characteristics of local lamellipodia were assessed before and after addition of histamine. Changes in barrier function were determined using electrical cell-substrate impedance sensing. Histamine initially decreased barrier function, lamellipodia protrusion frequency, and lamellipodia protrusion distance. A longer time for lamellipodia withdrawal and reduced withdrawal distance and velocity accompanied barrier recovery. After barrier recovery, a significant number of cortical fibers migrated centrally, eventually resembling actin stress fibers. The p38 MAP kinase inhibitor SB203580 attenuated the histamine-induced decreases in barrier function and lamellipodia protrusion frequency. SB203580 also inhibited the histamine-induced decreases in withdrawal distance and velocity, and the subsequent actin fiber migration. These data suggest that histamine can reduce local lamellipodia protrusion activity through activation of p38 MAP kinase. The findings also suggest that local lamellipodia have a role in maintaining endothelial barrier integrity. Furthermore, we provide evidence that actin stress fiber formation may be a reaction to, rather than a cause of, reduced endothelial barrier integrity.

  4. Transient Intervals of Hyper-Gravity Enhance Endothelial Barrier Integrity: Impact of Mechanical and Gravitational Forces Measured Electrically.

    PubMed

    Szulcek, Robert; van Bezu, Jan; Boonstra, Johannes; van Loon, Jack J W A; van Nieuw Amerongen, Geerten P

    2015-01-01

    Endothelial cells (EC) guard vascular functions by forming a dynamic barrier throughout the vascular system that sensitively adapts to 'classical' biomechanical forces, such as fluid shear stress and hydrostatic pressure. Alterations in gravitational forces might similarly affect EC integrity, but remain insufficiently studied. In an unique approach, we utilized Electric Cell-substrate Impedance Sensing (ECIS) in the gravity-simulators at the European Space Agency (ESA) to study dynamic responses of human EC to simulated micro- and hyper-gravity as well as to classical forces. Short intervals of micro- or hyper-gravity evoked distinct endothelial responses. Stimulated micro-gravity led to decreased endothelial barrier integrity, whereas hyper-gravity caused sustained barrier enhancement by rapid improvement of cell-cell integrity, evidenced by a significant junctional accumulation of VE-cadherin (p = 0.011), significant enforcement of peripheral F-actin (p = 0.008) and accompanied by a slower enhancement of cell-matrix interactions. The hyper-gravity triggered EC responses were force dependent and nitric-oxide (NO) mediated showing a maximal resistance increase of 29.2±4.8 ohms at 2g and 60.9±6.2 ohms at 4g vs. baseline values that was significantly suppressed by NO blockage (p = 0.011). In conclusion, short-term application of hyper-gravity caused a sustained improvement of endothelial barrier integrity, whereas simulated micro-gravity weakened the endothelium. In clear contrast, classical forces of shear stress and hydrostatic pressure induced either short-lived or no changes to the EC barrier. Here, ECIS has proven a powerful tool to characterize subtle and distinct EC gravity-responses due to its high temporal resolution, wherefore ECIS has a great potential for the study of gravity-responses such as in real space flights providing quantitative assessment of a variety of cell biological characteristics of any adherent growing cell type in an automated and

  5. Endothelial cell heterogeneity of blood-brain barrier gene expression along the cerebral microvasculature.

    PubMed

    Macdonald, Jennifer A; Murugesan, Nivetha; Pachter, Joel S

    2010-05-15

    The blood-brain barrier (BBB) refers to the network of microvessels that selectively restricts the passage of substances between the circulation and the central nervous system (CNS). This microvascular network is comprised of arterioles, capillaries and venules, yet the respective contribution of each of these to the BBB awaits clarification. In this regard, it has been postulated that brain microvascular endothelial cells (BMEC) from these different tributaries might exhibit considerable heterogeneity in form and function, with such diversity underlying unique roles in physiological and pathophysiological processes. Means to begin exploring such endothelial differences in situ, free from caveats associated with cell isolation and culturing procedures, are crucial to comprehending the nature and treatment of CNS diseases with vascular involvement. Here, the recently validated approach of immuno-laser capture microdissection (immuno-LCM) coupled to quantitative real-time PCR (qRT-PCR) was used to analyze gene expression patterns of BMEC retrieved in situ from either capillaries or venules. From profiling 87 genes known to play a role in BBB function and/or be enriched in isolated brain microvessels, results imply that most BBB properties reside in both segments, but that capillaries preferentially express some genes related to solute transport, while venules tend toward higher expression of an assortment of genes involved in inflammatory-related tasks. Fuller appreciation of such heterogeneity will be critical for efficient therapeutic targeting of the endothelium and the management of CNS disease.

  6. Derivation of blood-brain barrier endothelial cells from human pluripotent stem cells.

    PubMed

    Lippmann, Ethan S; Azarin, Samira M; Kay, Jennifer E; Nessler, Randy A; Wilson, Hannah K; Al-Ahmad, Abraham; Palecek, Sean P; Shusta, Eric V

    2012-08-01

    The blood-brain barrier (BBB) is crucial to the health of the brain and is often compromised in neurological disease. Moreover, because of its barrier properties, this endothelial interface restricts uptake of neurotherapeutics. Thus, a renewable source of human BBB endothelium could spur brain research and pharmaceutical development. Here we show that endothelial cells derived from human pluripotent stem cells (hPSCs) acquire BBB properties when co-differentiated with neural cells that provide relevant cues, including those involved in Wnt/β-catenin signaling. The resulting endothelial cells have many BBB attributes, including well-organized tight junctions, appropriate expression of nutrient transporters and polarized efflux transporter activity. Notably, they respond to astrocytes, acquiring substantial barrier properties as measured by transendothelial electrical resistance (1,450 ± 140 Ω cm2), and they possess molecular permeability that correlates well with in vivo rodent blood-brain transfer coefficients.

  7. Microcapsules functionalized with neuraminidase can enter vascular endothelial cells in vitro

    PubMed Central

    Liu, Weizhi; Wang, Xiaocong; Bai, Ke; Lin, Miao; Sukhorukov, Gleb; Wang, Wen

    2014-01-01

    Microcapsules made of polyelectrolyte multilayers exhibit no or low toxicity, appropriate mechanical stability, variable controllable degradation and can incorporate remote release mechanisms triggered by various stimuli, making them well suited for targeted drug delivery to live cells. This study investigates interactions between microcapsules made of synthetic (i.e. polystyrenesulfonate sodium salt/polyallylamine hydrochloride) or natural (i.e. dextran sulfate/poly-l-arginine) polyelectrolyte and human umbilical vein endothelial cells with particular focus on the effect of the glycocalyx layer on the intake of microcapsules by endothelial cells. Neuraminidase cleaves N-acetyl neuraminic acid residues of glycoproteins and targets the sialic acid component of the glycocalyx on the cell membrane. Three-dimensional confocal images reveal that microcapsules, functionalized with neuraminidase, can be internalized by endothelial cells. Capsules without neuraminidase are blocked by the glycocalyx layer. Uptake of the microcapsules is most significant in the first 2 h. Following their internalization by endothelial cells, biodegradable DS/PArg capsules rupture by day 5; however, there is no obvious change in the shape and integrity of PSS/PAH capsules within the period of observation. Results from the study support our hypothesis that the glycocalyx functions as an endothelial barrier to cross-membrane movement of microcapsules. Neuraminidase-loaded microcapsules can enter endothelial cells by localized cleavage of glycocalyx components with minimum disruption of the glycocalyx layer and therefore have high potential to act as drug delivery vehicles to reach tissues beyond the endothelial barrier of blood vessels. PMID:25339691

  8. CD146 coordinates brain endothelial cell-pericyte communication for blood-brain barrier development.

    PubMed

    Chen, Jianan; Luo, Yongting; Hui, Hui; Cai, Tanxi; Huang, Hongxin; Yang, Fuquan; Feng, Jing; Zhang, Jingjing; Yan, Xiyun

    2017-09-05

    The blood-brain barrier (BBB) establishes a protective interface between the central neuronal system and peripheral blood circulation and is crucial for homeostasis of the CNS. BBB formation starts when the endothelial cells (ECs) invade the CNS and pericytes are recruited to the nascent vessels during embryogenesis. Despite the essential function of pericyte-EC interaction during BBB development, the molecular mechanisms coordinating the pericyte-EC behavior and communication remain incompletely understood. Here, we report a single cell receptor, CD146, that presents dynamic expression patterns in the cerebrovasculature at the stages of BBB induction and maturation, coordinates the interplay of ECs and pericytes, and orchestrates BBB development spatiotemporally. In mouse brain, CD146 is first expressed in the cerebrovascular ECs of immature capillaries without pericyte coverage; with increased coverage of pericytes, CD146 could only be detected in pericytes, but not in cerebrovascular ECs. Specific deletion of Cd146 in mice ECs resulted in reduced brain endothelial claudin-5 expression and BBB breakdown. By analyzing mice with specific deletion of Cd146 in pericytes, which have defects in pericyte coverage and BBB integrity, we demonstrate that CD146 functions as a coreceptor of PDGF receptor-β to mediate pericyte recruitment to cerebrovascular ECs. Moreover, we found that the attached pericytes in turn down-regulate endothelial CD146 by secreting TGF-β1 to promote further BBB maturation. These results reveal that the dynamic expression of CD146 controls the behavior of ECs and pericytes, thereby coordinating the formation of a mature and stable BBB.

  9. Mineralocorticoid receptor antagonists and endothelial function

    PubMed Central

    Maron, Bradley A.; Leopold, Jane A.

    2010-01-01

    Hyperaldosteronism has been associated with endothelial dysfunction and impaired vascular reactivity in patients with hypertension or congestive heart failure. The mineralocorticoid receptor (MR) antagonists spironolactone and eplerenone have been shown to reduce morbidity and mortality, in part, by ameliorating the adverse effects of aldosterone on vascular function. Although spironolactone and eplerenone are increasingly utilized in patients with cardiovascular disease, widespread clinical use is limited by the development of gynecomastia with spironolactone and hyperkalemia with both agents. This suggests that the development of newer agents with favorable side effect profiles is warranted. PMID:18729003

  10. Plasmodium falciparum Histones Induce Endothelial Proinflammatory Response and Barrier Dysfunction

    PubMed Central

    Gillrie, Mark R.; Lee, Kristine; Gowda, D. Channe; Davis, Shevaun P.; Monestier, Marc; Cui, Liwang; Hien, Tran Tinh; Day, Nicholas P.J.; Ho, May

    2012-01-01

    Plasmodium falciparum is a protozoan parasite of human erythrocytes that causes the most severe form of malaria. Severe P. falciparum infection is associated with endothelial activation and permeability, which are important determinants of the outcome of the infection. How endothelial cells become activated is not fully understood, particularly with regard to the effects of parasite subcomponents. We demonstrated that P. falciparum histones extracted from merozoites (HeH) directly stimulated the production of IL-8 and other inflammatory mediators by primary human dermal microvascular endothelial cells through a signaling pathway that involves Src family kinases and p38 MAPK. The stimulatory effect of HeH and recombinant P. falciparum H3 (PfH3) was abrogated by histone-specific antibodies. The release of nuclear contents on rupture of infected erythrocytes was captured by live cell imaging and confirmed by detecting nucleosomes in the supernatants of parasite cultures. HeH and recombinant parasite histones also induced endothelial permeability through a charge-dependent mechanism that resulted in disruption of junctional protein expression and cell death. Recombinant human activated protein C cleaved HeH and PfH3 and abrogated their proinflammatory effects. Circulating nucleosomes of both human and parasite origin were detected in the plasma of patients with falciparum malaria and correlated positively with disease severity. These results support a pathogenic role for both host- and pathogen-derived histones in P. falciparum-caused malaria. PMID:22260922

  11. Stiffness of polyelectrolyte multilayer film influences endothelial function of endothelial cell monolayer.

    PubMed

    Chang, Hao; Zhang, He; Hu, Mi; Chen, Jia-Yan; Li, Bo-Chao; Ren, Ke-Feng; Martins, M Cristina L; Barbosa, Mário A; Ji, Jian

    2017-01-01

    Endothelialization has proved to be critical for maintaining long-term success of implantable vascular devices. The formation of monolayer of endothelial cells (ECs) on the implant surfaces is one of the most important factors for the endothelialization. However, endothelial function of regenerated EC monolayer, which plays a much more important role in preventing the complications of post-implantation, has not received enough attention. Here, a vascular endothelial growth factor (VEGF)-incorporated poly(l-lysine)/hyaluronan (PLL/HA) polyelectrolyte multilayer film was fabricated. Through varying the crosslinking degree, stiffness of the film was manipulated, offering either soft or stiff film. We demonstrated that ECs were able to adhere and proliferate on both soft and stiff films, subsequently forming an integrated EC monolayer. Furthermore, endothelial functions were evaluated by characterizing EC monolayer integrity, expression of genes correlated with the endothelial functions, and nitric oxide production. It demonstrated that EC monolayer on the soft film displayed higher endothelial function compared to that on the stiff film. Our study highlights the influence of substrate stiffness on endothelial function, which offers a new criterion for surface design of vascular implants. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Methamphetamine is not Toxic but Disrupts the Cell Cycle of Blood-Brain Barrier Endothelial Cells.

    PubMed

    Fisher, D; Gamieldien, K; Mafunda, P S

    2015-07-01

    The cytotoxic effects of methamphetamine (MA) are well established to be caused via induced oxidative stress which in turn compromises the core function of the blood-brain barrier (BBB) by reducing its ability to regulate the homeostatic environment of the brain. While most studies were conducted over a period of 24-48 h, this study investigated the mechanisms by which chronic exposure of MA adversely affect the endothelial cells of BBB over an extended period of 96 h. MA induced significant depression of cell numbers at 96 h. This result was supported by flow cytometric data on the cell cycle which showed that brain endothelial cells (bEnd5) at 96 h were significantly suppressed in the S-phase of the cell cycle. In contrast, at 24-72 h control cell numbers for G1, S and G2-M phases were similar to MA-exposed cells. MA (0-1,000 µM) did not, however, statistically affect the viability and cytotoxicity of the bEnd5 cells, and the profile of ATP production and DNA synthesis (BrdU) across 96 h did not provide a rationale for the suppression of cell division. Our study reports for the first time that chronic exposure to MA results in long-term disruption of the cell cycle phases which eventuates in the attenuation of brain capillary endothelial cell growth after 96 h, compounding and contributing to the already well-known adverse short-term permeability effects of MA exposure on the BBB.

  13. Akt1 promotes stimuli-induced endothelial-barrier protection through FoxO-mediated tight-junction protein turnover.

    PubMed

    Gao, Fei; Artham, Sandeep; Sabbineni, Harika; Al-Azayzih, Ahmad; Peng, Xiao-Ding; Hay, Nissim; Adams, Ralf H; Byzova, Tatiana V; Somanath, Payaningal R

    2016-10-01

    Vascular permeability regulated by the vascular endothelial growth factor (VEGF) through endothelial-barrier junctions is essential for inflammation. Mechanisms regulating vascular permeability remain elusive. Although 'Akt' and 'Src' have been implicated in the endothelial-barrier regulation, it is puzzling how both agents that protect and disrupt the endothelial-barrier activate these kinases to reciprocally regulate vascular permeability. To delineate the role of Akt1 in endothelial-barrier regulation, we created endothelial-specific, tamoxifen-inducible Akt1 knockout mice and stable ShRNA-mediated Akt1 knockdown in human microvascular endothelial cells. Akt1 loss leads to decreased basal and angiopoietin1-induced endothelial-barrier resistance, and enhanced VEGF-induced endothelial-barrier breakdown. Endothelial Akt1 deficiency resulted in enhanced VEGF-induced vascular leakage in mice ears, which was rescued upon re-expression with Adeno-myrAkt1. Furthermore, co-treatment with angiopoietin1 reversed VEGF-induced vascular leakage in an Akt1-dependent manner. Mechanistically, our study revealed that while VEGF-induced short-term vascular permeability is independent of Akt1, its recovery is reliant on Akt1 and FoxO-mediated claudin expression. Pharmacological inhibition of FoxO transcription factors rescued the defective endothelial barrier due to Akt1 deficiency. Here we provide novel insights on the endothelial-barrier protective role of VEGF in the long term and the importance of Akt1-FoxO signaling on tight-junction stabilization and prevention of vascular leakage through claudin expression.

  14. Human Blood-Brain Barrier Endothelial Cells Derived from Pluripotent Stem Cells

    PubMed Central

    Lippmann, Ethan S.; Azarin, Samira M.; Kay, Jennifer E.; Nessler, Randy A.; Wilson, Hannah K.; Al-Ahmad, Abraham; Palecek, Sean P.; Shusta, Eric V.

    2012-01-01

    The blood-brain barrier (BBB) plays an important role in brain health and is often compromised in disease. Moreover, as a result of its significant barrier properties, this endothelial interface restricts neurotherapeutic uptake. Thus, a renewable source of human BBB endothelium could prove enabling for brain research and pharmaceutical development. Herein, we demonstrate that endothelial cells generated from human pluripotent stem cells (hPSCs) can be specified to possess many BBB attributes, including well-organized tight junctions, expression of nutrient transporters, and polarized efflux transporter activity. Importantly, hPSC-derived BBB endothelial cells respond to astrocytic cues yielding impressive barrier properties as measured by transendothelial electrical resistance (1450±140 Ωxcm2) and molecular permeability that correlates well with in vivo brain uptake. In addition, specification of hPSC-derived BBB endothelial cells occurs in concert with neural cell co-differentiation via Wnt/β-catenin signaling, consistent with previous transgenic studies. This study represents the first example of organ-specific endothelial differentiation from hPSCs. PMID:22729031

  15. Moisturization and skin barrier function.

    PubMed

    Rawlings, A V; Harding, C R

    2004-01-01

    Over the past decade, great progress has been made toward elucidating the structure and function of the stratum corneum (SC), the outermost layer of the epidermis. SC cells (corneocytes) protect against desiccation and environmental challenge by regulating water flux and retention. Maintenance of an optimal level of hydration by the SC is largely dependent on several factors. First, intercellular lamellar lipids, organized predominantly in an orthorhombic gel phase, provide an effective barrier to the passage of water through the tissue. Secondly, the diffusion path length also retards water loss, since water must traverse the tortuous path created by the SC layers and corneocyte envelopes. Thirdly, and equally important, is natural moisturizing factor (NMF), a complex mixture of low-molecular-weight, water-soluble compounds first formed within the corneocytes by degradation of the histidine-rich protein known as filaggrin. Each maturation step leading to the formation of an effective moisture barrier--including corneocyte strengthening, lipid processing, and NMF generation--is influenced by the level of SC hydration. These processes, as well as the final step of corneodesmolysis that mediates exfoliation, are often disturbed upon environmental challenge, resulting in dry, flaky skin conditions. The present paper reviews our current understanding of the biology of the SC, particularly its homeostatic mechanisms of hydration.

  16. The role of intrinsic apoptotic signaling in hemorrhagic shock-induced microvascular endothelial cell barrier dysfunction.

    PubMed

    Sawant, Devendra A; Tharakan, Binu; Hunter, Felicia A; Childs, Ed W

    2014-11-01

    Hemorrhagic shock leads to endothelial cell barrier dysfunction resulting in microvascular hyperpermeability. Hemorrhagic shock-induced microvascular hyperpermeability is associated with worse clinical outcomes in patients with traumatic injuries. The results from our laboratory have illustrated a possible pathophysiological mechanism showing involvement of mitochondria-mediated "intrinsic" apoptotic signaling in regulating hemorrhagic shock-induced microvascular hyperpermeability. Hemorrhagic shock results in overexpression of Bcl-2 family of pro-apoptotic protein, BAK, in the microvascular endothelial cells. The increase in BAK initiates "intrinsic" apoptotic signaling cascade with the release of mitochondrial cytochrome c in the cytoplasm and activation of downstream effector caspase-3, leading to loss of endothelial cell barrier integrity. Thus, this review article offers a brief overview of important findings from our past and present research work along with new leads for future research. The summary of our research work will provide information leading to different avenues in developing novel strategies against microvascular hyperpermeability following hemorrhagic shock.

  17. MALT1 Protease Activation Triggers Acute Disruption of Endothelial Barrier Integrity via CYLD Cleavage.

    PubMed

    Klei, Linda R; Hu, Dong; Panek, Robert; Alfano, Danielle N; Bridwell, Rachel E; Bailey, Kelly M; Oravecz-Wilson, Katherine I; Concel, Vincent J; Hess, Emily M; Van Beek, Matthew; Delekta, Phillip C; Gu, Shufang; Watkins, Simon C; Ting, Adrian T; Gough, Peter J; Foley, Kevin P; Bertin, John; McAllister-Lucas, Linda M; Lucas, Peter C

    2016-09-27

    Microvascular endothelial cells maintain a tight barrier to prevent passage of plasma and circulating immune cells into the extravascular tissue compartment, yet endothelial cells respond rapidly to vasoactive substances, including thrombin, allowing transient paracellular permeability. This response is a cornerstone of acute inflammation, but the mechanisms responsible are still incompletely understood. Here, we demonstrate that thrombin triggers MALT1 to proteolytically cleave cylindromatosis (CYLD). Fragmentation of CYLD results in microtubule disruption and a cascade of events leading to endothelial cell retraction and an acute permeability response. This finding reveals an unexpected role for the MALT1 protease, which previously has been viewed mostly as a driver of pro-inflammatory NF-κB signaling in lymphocytes. Thus, MALT1 not only promotes immune cell activation but also acutely regulates endothelial cell biology, actions that together facilitate tissue inflammation. Pharmacologic inhibition of MALT1 may therefore have synergistic impact by targeting multiple disparate steps in the overall inflammatory response.

  18. Functions for the cAMP/Epac/Rap1 Signaling Pathway in Low-Dose Endothelial Monocyte-Activating Polypeptide-II-Induced Opening of Blood-Tumor Barrier.

    PubMed

    Li, Zhen; Liu, Xiao-Bai; Liu, Yun-Hui; Xue, Yi-Xue; Wang, Ping; Liu, Li-Bo; Yao, Yi-Long; Ma, Jun

    2015-09-01

    Previous studies have demonstrated that low-dose endothelial monocyte-activating polypeptide-II (EMAP-II) induces blood-tumor barrier (BTB) hyperpermeability via both paracellular and transcellular pathways. In a recent study, we revealed that cAMP/PKA-dependent and cAMP/PKA-independent signaling pathways are both involved in EMAP-II-induced BTB hyperpermeability. The present study further investigated the exact mechanisms through which the cAMP/PKA-independent signaling pathway affects EMAP-II-induced BTB hyperpermeability. In an in vitro BTB model, low-dose EMAP-II (0.05 nM) induced a significant decrease in Rap1 activity in RBMECs. Pretreatment with forskolin to elevate intracellular cAMP concentration completely blocked EMAP-II-induced Rap1 inactivation. Epac/Rap1 activation by 8-pCPT-2'-O-Me-cAMP significantly prevented EMAP-II-induced activation of RhoA/ROCK. Furthermore, 8-pCPT-2'-O-Me-cAMP pretreatment significantly inhibited EMAP-II-induced decreases in TEER and increases in HRP flux. Pretreatment also significantly prevented EMAP-II-induced changes in MLC phosphorylation, actin cytoskeleton arrangement, and expression and distribution of ZO-1 in RBMECs. This study demonstrates that the cAMP/Epac/Rap1 signaling cascade is a crucial pathway in EMAP-II-induced BTB hyperpermeability.

  19. Epidermal Vascular Endothelial Growth Factor Production Is Required for Permeability Barrier Homeostasis, Dermal Angiogenesis, and the Development of Epidermal Hyperplasia

    PubMed Central

    Elias, Peter M.; Arbiser, Jack; Brown, Barbara E.; Rossiter, Heidemarie; Man, Mao-Qiang; Cerimele, Francesca; Crumrine, Debra; Gunathilake, Roshan; Choi, Eung Ho; Uchida, Yoshikazu; Tschachler, Erwin; Feingold, Kenneth R.

    2008-01-01

    Primary abnormalities in permeability barrier function appear to underlie atopic dermatitis and epidermal trauma; a concomitant barrier dysfunction could also drive other inflammatory dermatoses, including psoriasis. Central to this outside-inside view of disease pathogenesis is the epidermal generation of cytokines/growth factors, which in turn signal downstream epidermal repair mechanisms. Yet, this cascade, if sustained, signals downstream epidermal hyperplasia and inflammation. We found here that acute barrier disruption rapidly stimulates mRNA and protein expression of epidermal vascular endothelial growth factor-A (VEGF-A) in normal hairless mice, a specific response to permeability barrier requirements because up-regulation is blocked by application of a vapor-impermeable membrane. Moreover, epidermal vegf−/− mice display abnormal permeability barrier homeostasis, attributable to decreased VEGF signaling of epidermal lamellar body production; a paucity of dermal capillaries with reduced vascular permeability; and neither angiogenesis nor epidermal hyperplasia in response to repeated tape stripping (a model of psoriasiform hyperplasia). These results support a central role for epidermal VEGF in the maintenance of epidermal permeability barrier homeostasis and a link between epidermal VEGF production and both dermal angiogenesis and the development of epidermal hyperplasia. Because psoriasis is commonly induced by external trauma [isomorphic (Koebner) phenomenon] and is associated with a prominent permeability barrier abnormality, excess VEGF production, prominent angiogenesis, and epidermal hyperplasia, these results could provide a potential outside-inside mechanistic basis for the development of psoriasis. PMID:18688025

  20. Exosomes derived from endothelial progenitor cells attenuate vascular repair and accelerate reendothelialization by enhancing endothelial function.

    PubMed

    Li, Xiaocong; Chen, Chunyuan; Wei, Liming; Li, Qing; Niu, Xin; Xu, Yanjun; Wang, Yang; Zhao, Jungong

    2016-02-01

    Exosomes, a key component of cell paracrine secretion, can exert protective effects in various disease models. However, application of exosomes in vascular repair and regeneration has rarely been reported. In this study, we tested whether endothelial progenitor cell (EPC)-derived exosomes possessed therapeutic effects in rat models of balloon-induced vascular injury by accelerating reendothelialization. Exosomes were obtained from the conditioned media of EPCs isolated from human umbilical cord blood. Induction of the endothelial injury was performed in the rats' carotid artery, and the pro-re-endothelialization capacity of EPC-derived exosomes was measured. The in vitro effects of exosomes on the proliferation and migration of endothelial cells were investigated. We found that the EPC-derived exosomes accelerated the re-endothelialization in the early phase after endothelial damage in the rat carotid artery. We also demonstrated that these exosomes enhanced the proliferation and migration of endothelial cells in vitro. Moreover, endothelial cells stimulated with these exosomes showed increased expression of angiogenesis-related molecules. Taken together, our results indicate that exosomes are an active component of the paracrine secretion of human EPCs and can promote vascular repair in rat models of balloon injury by up-regulating endothelial cells function. Copyright © 2015. Published by Elsevier Inc.

  1. Concepts for Functional Restoration of Barrier Islands

    DTIC Science & Technology

    2009-09-01

    Frisian barrier islands to sea-level rise: An investigation of past and future evolution. Geomorphology 15, 57-65. Farley, P. P. 1923. Coney Island ...ERDC/CHL CHETN-IV-74 September 2009 Concepts for Functional Restoration of Barrier Islands by Julie Dean Rosati PURPOSE: This Coastal and...Hydraulics Engineering Technical Note (CHETN) presents guid- ance for functional restoration of barrier islands . The concept of functional restoration

  2. Loss of cortactin causes endothelial barrier dysfunction via disturbed adrenomedullin secretion and actomyosin contractility.

    PubMed

    García Ponce, Alexander; Citalán Madrid, Alí F; Vargas Robles, Hilda; Chánez Paredes, Sandra; Nava, Porfirio; Betanzos, Abigail; Zarbock, Alexander; Rottner, Klemens; Vestweber, Dietmar; Schnoor, Michael

    2016-06-30

    Changes in vascular permeability occur during inflammation and the actin cytoskeleton plays a crucial role in regulating endothelial cell contacts and permeability. We demonstrated recently that the actin-binding protein cortactin regulates vascular permeability via Rap1. However, it is unknown if the actin cytoskeleton contributes to increased vascular permeability without cortactin. As we consistently observed more actin fibres in cortactin-depleted endothelial cells, we hypothesised that cortactin depletion results in increased stress fibre contractility and endothelial barrier destabilisation. Analysing the contractile machinery, we found increased ROCK1 protein levels in cortactin-depleted endothelium. Concomitantly, myosin light chain phosphorylation was increased while cofilin, mDia and ERM were unaffected. Secretion of the barrier-stabilising hormone adrenomedullin, which activates Rap1 and counteracts actomyosin contractility, was reduced in plasma from cortactin-deficient mice and in supernatants of cortactin-depleted endothelium. Importantly, adrenomedullin administration and ROCK1 inhibition reduced actomyosin contractility and rescued the effect on permeability provoked by cortactin deficiency in vitro and in vivo. Our data suggest a new role for cortactin in controlling actomyosin contractility with consequences for endothelial barrier integrity.

  3. Electroporation of Brain Endothelial Cells on Chip toward Permeabilizing the Blood-Brain Barrier

    PubMed Central

    Bonakdar, Mohammad; Wasson, Elisa M.; Lee, Yong W.; Davalos, Rafael V.

    2016-01-01

    The blood-brain barrier, mainly composed of brain microvascular endothelial cells, poses an obstacle to drug delivery to the brain. Controlled permeabilization of the constituent brain endothelial cells can result in overcoming this barrier and increasing transcellular transport across it. Electroporation is a biophysical phenomenon that has shown potential in permeabilizing and overcoming this barrier. In this study we developed a microengineered in vitro model to characterize the permeabilization of adhered brain endothelial cells to large molecules in response to applied pulsed electric fields. We found the distribution of affected cells by reversible and irreversible electroporation, and quantified the uptaken amount of naturally impermeable molecules into the cells as a result of applied pulse magnitude and number of pulses. We achieved 81 ± 1.7% (N = 6) electroporated cells with 17 ± 8% (N = 5) cell death using an electric-field magnitude of ∼580 V/cm and 10 pulses. Our results provide the proper range for applied electric-field intensity and number of pulses for safe permeabilization without significantly compromising cell viability. Our results demonstrate that it is possible to permeabilize the endothelial cells of the BBB in a controlled manner, therefore lending to the feasibility of using pulsed electric fields to increase drug transport across the BBB through the transcellular pathway. PMID:26789772

  4. Electroporation of Brain Endothelial Cells on Chip toward Permeabilizing the Blood-Brain Barrier.

    PubMed

    Bonakdar, Mohammad; Wasson, Elisa M; Lee, Yong W; Davalos, Rafael V

    2016-01-19

    The blood-brain barrier, mainly composed of brain microvascular endothelial cells, poses an obstacle to drug delivery to the brain. Controlled permeabilization of the constituent brain endothelial cells can result in overcoming this barrier and increasing transcellular transport across it. Electroporation is a biophysical phenomenon that has shown potential in permeabilizing and overcoming this barrier. In this study we developed a microengineered in vitro model to characterize the permeabilization of adhered brain endothelial cells to large molecules in response to applied pulsed electric fields. We found the distribution of affected cells by reversible and irreversible electroporation, and quantified the uptaken amount of naturally impermeable molecules into the cells as a result of applied pulse magnitude and number of pulses. We achieved 81 ± 1.7% (N = 6) electroporated cells with 17 ± 8% (N = 5) cell death using an electric-field magnitude of ∼580 V/cm and 10 pulses. Our results provide the proper range for applied electric-field intensity and number of pulses for safe permeabilization without significantly compromising cell viability. Our results demonstrate that it is possible to permeabilize the endothelial cells of the BBB in a controlled manner, therefore lending to the feasibility of using pulsed electric fields to increase drug transport across the BBB through the transcellular pathway.

  5. Loss of cortactin causes endothelial barrier dysfunction via disturbed adrenomedullin secretion and actomyosin contractility

    PubMed Central

    García Ponce, Alexander; Citalán Madrid, Alí F.; Vargas Robles, Hilda; Chánez Paredes, Sandra; Nava, Porfirio; Betanzos, Abigail; Zarbock, Alexander; Rottner, Klemens; Vestweber, Dietmar; Schnoor, Michael

    2016-01-01

    Changes in vascular permeability occur during inflammation and the actin cytoskeleton plays a crucial role in regulating endothelial cell contacts and permeability. We demonstrated recently that the actin-binding protein cortactin regulates vascular permeability via Rap1. However, it is unknown if the actin cytoskeleton contributes to increased vascular permeability without cortactin. As we consistently observed more actin fibres in cortactin-depleted endothelial cells, we hypothesised that cortactin depletion results in increased stress fibre contractility and endothelial barrier destabilisation. Analysing the contractile machinery, we found increased ROCK1 protein levels in cortactin-depleted endothelium. Concomitantly, myosin light chain phosphorylation was increased while cofilin, mDia and ERM were unaffected. Secretion of the barrier-stabilising hormone adrenomedullin, which activates Rap1 and counteracts actomyosin contractility, was reduced in plasma from cortactin-deficient mice and in supernatants of cortactin-depleted endothelium. Importantly, adrenomedullin administration and ROCK1 inhibition reduced actomyosin contractility and rescued the effect on permeability provoked by cortactin deficiency in vitro and in vivo. Our data suggest a new role for cortactin in controlling actomyosin contractility with consequences for endothelial barrier integrity. PMID:27357373

  6. Fragmented oxidation products define barrier disruptive endothelial cell response to OxPAPC

    PubMed Central

    Birukova, Anna A.; Starosta, Vitaliy; Tian, Xinyong; Higginbotham, Katherine; Koroniak, Lukas; Berliner, Judith A.; Birukov, Konstantin G.

    2013-01-01

    Excessive concentrations of oxidized phospholipids (OxPL), the products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (PAPC) oxidation have been detected in atherosclerosis, septic inflammation, and ALI; and have been shown to induce vascular barrier dysfunction. In contrast, oxidized PAPC (OxPAPC) at low concentrations exhibit potent barrier protective effects. The nature of such biphasic effects remains unclear. We tested the hypothesis that barrier-disruptive effects of high OxPAPC doses on endothelial cell (EC) monolayer are defined by fragmented products of PAPC oxidation (lyso-PC, POVPC, PGPC), while barrier enhancing effects are mediated by full length oxidated PAPC products and may be reproduced by single compounds contained in the OxPAPC such as PEIPC. All three fragmented OxPAPC products increased EC permeability in a dose-dependent manner, while PEIPC decreased it and reversed barrier disruptive effects of lyso-PC, POVPC and PGPC monitored by measurements of transendothelial electrical resistance. Immunofluorescence staining and western blot analysis showed that PGPC mimicked the cytoskeletal remodeling and tyrosine phosphorylation of adherens junction (AJ) protein VE-cadherin leading to EC barrier dysfunction induced by high OxPAPC concentrations. Barrier-disruptive effects of PGPC were abrogated by ROS inhibitor, N-acetyl cysteine, or Src kinase inhibitor, PP-2. The results of this study show that barrier disruptive effects of fragmented OxPAPC constituents (lyso-PC, POVPC, PGPC) are balanced by barrier enhancing effects of full length oxygenated products (PEIPC). These data strongly suggest that barrier disruptive effects of OxPAPC at higher concentrations are dictated by predominant effects of fragmented phospholipids such as PGPC, which promote ROS-dependent activation of Src kinase and VE-cadherin phosphorylation at Tyr658 and Tyr731 leading to disruption of endothelial cell AJs. PMID:23305708

  7. miR-155 Modifies Inflammation, Endothelial Activation and Blood-Brain Barrier Dysfunction in Cerebral Malaria

    PubMed Central

    Barker, Kevin R; Lu, Ziyue; Kim, Hani; Zheng, Ying; Chen, Junmei; Conroy, Andrea L; Hawkes, Michael; Cheng, Henry S; Njock, Makon-Sébastien; Fish, Jason E; Harlan, John M; López, Jose A; Liles, W Conrad; Kain, Kevin C

    2017-01-01

    miR-155 has been shown to participate in host response to infection and neuroinflammation via negative regulation of blood-brain barrier (BBB) integrity and T cell function. We hypothesized that miR-155 may contribute to the pathogenesis of cerebral malaria (CM). To test this hypothesis, we used a genetic approach to modulate miR-155 expression in an experimental model of cerebral malaria (ECM). In addition, an engineered endothelialized microvessel system and serum samples from Ugandan children with CM were used to examine anti–miR-155 as a potential adjunctive therapeutic for severe malaria. Despite higher parasitemia, survival was significantly improved in miR-155-/- mice versus wild-type littermate mice in ECM. Improved survival was associated with preservation of BBB integrity and reduced endothelial activation, despite increased levels of proinflammatory cytokines. Pretreatment with antagomir-155 reduced vascular leak induced by human CM sera in an ex vivo endothelial microvessel model. These data provide evidence supporting a mechanistic role for miR-155 in host response to malaria via regulation of endothelial activation, microvascular leak and BBB dysfunction in CM. PMID:28182191

  8. 25-Hydroxycholesterol impairs endothelial function and vasodilation by uncoupling and inhibiting endothelial nitric oxide synthase.

    PubMed

    Ou, Zhi-Jun; Chen, Jing; Dai, Wei-Ping; Liu, Xiang; Yang, Yin-Ke; Li, Yan; Lin, Ze-Bang; Wang, Tian-Tian; Wu, Ying-Ying; Su, Dan-Hong; Cheng, Tian-Pu; Wang, Zhi-Ping; Tao, Jun; Ou, Jing-Song

    2016-10-01

    Endothelial dysfunction is a key early step in atherosclerosis. 25-Hydroxycholesterol (25-OHC) is found in atherosclerotic lesions. However, whether 25-OHC promotes atherosclerosis is unclear. Here, we hypothesized that 25-OHC, a proinflammatory lipid, can impair endothelial function, which may play an important role in atherosclerosis. Bovine aortic endothelial cells were incubated with 25-OHC. Endothelial cell proliferation, migration, and tube formation were measured. Nitric oxide (NO) production and superoxide anion generation were determined. The expression and phosphorylation of endothelial NO synthase (eNOS) and Akt as well as the association of eNOS and heat shock protein (HSP)90 were detected by immunoblot analysis and immunoprecipitation. Endothelial cell apoptosis was monitored by TUNEL staining and caspase-3 activity, and expression of Bcl-2, Bax, cleaved caspase-9, and cleaved caspase-3 were detected by immunoblot analysis. Finally, aortic rings from Sprague-Dawley rats were isolated and treated with 25-OHC, and endothelium-dependent vasodilation was evaluated. 25-OHC significantly inhibited endothelial cell proliferation, migration, and tube formation. 25-OHC markedly decreased NO production and increased superoxide anion generation. 25-OHC reduced the phosphorylation of Akt and eNOS and the association of eNOS and HSP90. 25-OHC also enhanced endothelial cell apoptosis by decreasing Bcl-2 expression and increasing cleaved caspase-9 and cleaved caspase-3 expressions as well as caspase-3 activity. 25-OHC impaired endothelium-dependent vasodilation. These data demonstrated that 25-OHC could impair endothelial function by uncoupling and inhibiting eNOS activity as well as by inducing endothelial cell apoptosis. Our findings indicate that 25-OHC may play an important role in regulating atherosclerosis. Copyright © 2016 the American Physiological Society.

  9. Androgens Modulate Endothelial Function and Endothelial Progenitor Cells in Erectile Physiology

    PubMed Central

    Galoosian, Artin

    2013-01-01

    The incidence of erectile dysfunction (ED) increases with age and cardiovascular disease risk factors, such as hypertension, hyperlipidemia, insulin resistance, obesity, and diabetes. These risk factors are thought to contribute to endothelial dysfunction and atherosclerosis, thus contributing to the pathophysiology of ED. The role of the endothelium in regulating erectile physiology is well established. However, the role of androgens in modulating endothelial function and endothelial repair mechanisms subsequent to vascular injury in erectile tissue remains a subject of intensive research. The clinical and preclinical evidence discussed in this review suggests that androgens regulate endothelial function and also play an important role in the development and maturation of endothelial progenitor cells (EPCs), which are thought to play a critical role in repair of endothelial injury in vascular beds. In this review, we discuss the data available on the effects of androgens on endothelial function and EPCs in the repair of vascular injury. Indeed, more research is needed to fully understand the molecular and cellular basis of androgen action in regulating the development, differentiation, maturation, migration, and homing of EPCs to the site of injury. A better understanding of these processes will be critical to the development of new therapeutic approaches to the treatment of vascular ED. PMID:24255752

  10. In vitro models of the blood-brain barrier: An overview of commonly used brain endothelial cell culture models and guidelines for their use.

    PubMed

    Helms, Hans C; Abbott, N Joan; Burek, Malgorzata; Cecchelli, Romeo; Couraud, Pierre-Olivier; Deli, Maria A; Förster, Carola; Galla, Hans J; Romero, Ignacio A; Shusta, Eric V; Stebbins, Matthew J; Vandenhaute, Elodie; Weksler, Babette; Brodin, Birger

    2016-05-01

    The endothelial cells lining the brain capillaries separate the blood from the brain parenchyma. The endothelial monolayer of the brain capillaries serves both as a crucial interface for exchange of nutrients, gases, and metabolites between blood and brain, and as a barrier for neurotoxic components of plasma and xenobiotics. This "blood-brain barrier" function is a major hindrance for drug uptake into the brain parenchyma. Cell culture models, based on either primary cells or immortalized brain endothelial cell lines, have been developed, in order to facilitate in vitro studies of drug transport to the brain and studies of endothelial cell biology and pathophysiology. In this review, we aim to give an overview of established in vitro blood-brain barrier models with a focus on their validation regarding a set of well-established blood-brain barrier characteristics. As an ideal cell culture model of the blood-brain barrier is yet to be developed, we also aim to give an overview of the advantages and drawbacks of the different models described. © The Author(s) 2016.

  11. VE-cadherin involved in the pulmonary microvascular endothelial cell barrier injury induced by angiotensin II through modulating the cellular apoptosis and skeletal rearrangement

    PubMed Central

    Wu, Zhiyong; Liu, Huagang; Ren, Wei; Dai, Feifeng; Chang, Jinxing; Li, Bowen

    2016-01-01

    Objective: Angiotensin II (AngII) involved in the pathogenesis of pulmonary injury through impairing the integrity of pulmonary microvascular endothelial barrier, but the mechanism is still not clear. We aim to determine the roles of VE-cadherin, playing crucial roles in the adhesion of the vascular endothelial barrier and the barrier function, in the pulmonary microvascular endothelial cell (PMVEC) barrier injury mediated by AngII. Methods: Mice acute lung injury (ALI) model was induced through pumping of AngII. The infiltration of macrophages and neutrophils as well as the PMVEC permeability were determined in order to determine the barrier injury in vivo and in vitro. Knockdown of VE-cadherin was established using siRNA technique, and its roles in the apoptosis and skeletal rearrangement in the PMVECs were evaluated. Results: After AngII interference, the expression of VE-cadherin in the PMVECs and pulmonary tissues in mice was down-regulated. Upon VE-cadherin knockdown through siRNA technique, AngII induced susceptibility of PMVECs to apoptosis. Knockdown of VE-cadherin contributed to the skeletal rearrangement in the endothelial cells, together with increase of permeability. Conclusions: VE-cadherin expression is closely related to the apoptosis and skeletal rearrangement of PMVECs induced by AngII. PMID:27830014

  12. Treatments Improving Skin Barrier Function.

    PubMed

    Lodén, Marie

    2016-01-01

    Moisturizers affect the stratum corneum architecture and barrier homeostasis, i.e. topically applied ingredients are not as inert to the skin as one might expect. A number of different mechanisms behind the barrier-influencing effects of moisturizers have been suggested, such as simple deposition of lipid material outside the skin. Ingredients in the moisturizers may also change the lamellar organization and the packing of the lipid matrix and thereby skin permeability. Topically applied substances may also penetrate deeper into the skin and interfere with the production of barrier lipids and the maturation of corneocytes. Furthermore, moisturizing creams may influence the desquamatory proteases and alter the thickness of the stratum corneum.

  13. Early radiation-induced endothelial cell loss and blood-spinal cord barrier breakdown in the rat spinal cord.

    PubMed

    Li, Yu-Qing; Chen, Paul; Jain, Vipan; Reilly, Raymond M; Wong, C Shun

    2004-02-01

    Using a rat spinal cord model, this study was designed to characterize radiation-induced vascular endothelial cell loss and its relationship to early blood-brain barrier disruption in the central nervous system. Adult rats were given a single dose of 0, 2, 8, 19.5, 22, 30 or 50 Gy to the cervical spinal cord. At various times up to 2 weeks after irradiation, the spinal cord was processed for histological and immunohistochemical analysis. Radiation-induced apoptosis was assessed by morphology and TdT-mediated dUTP nick end labeling combined with immunohistochemical markers for endothelial and glial cells. Image analysis was performed to determine endothelial cell and microvessel density using immunohistochemistry with endothelial markers, namely endothelial barrier antigen, glucose transporter isoform 1, laminin and zonula occludens 1. Blood-spinal cord barrier permeability was assessed using immunohistochemistry for albumin and (99m)Tc-diethylenetriamine pentaacetic acid as a vascular tracer. Endothelial cell proliferation was assessed using in vivo BrdU labeling. During the first 24 h after irradiation, apoptotic endothelial cells were observed in the rat spinal cord. The decrease in endothelial cell density at 24 h after irradiation was associated with an increase in albumin immunostaining around microvessels. The decrease in the number of endothelial cells persisted for 7 days and recovery of endothelial density was apparent by day 14. A similar pattern of blood-spinal cord barrier disruption and recovery of permeability was observed over the 2 weeks, and an increase in BrdU-labeled endothelial cells was seen at day 3. These results are consistent with an association between endothelial cell death and acute blood-spinal cord barrier disruption in the rat spinal cord after irradiation.

  14. Evaluation of Bioenergetic Function in Cerebral Vascular Endothelial Cells.

    PubMed

    Rellick, Stephanie L; Hu, Heng; Simpkins, James W; Ren, Xuefang

    2016-11-19

    The integrity of the blood-brain-barrier (BBB) is critical to prevent brain injury. Cerebral vascular endothelial (CVE) cells are one of the cell types that comprise the BBB; these cells have a very high-energy demand, which requires optimal mitochondrial function. In the case of disease or injury, the mitochondrial function in these cells can be altered, resulting in disease or the opening of the BBB. In this manuscript, we introduce a method to measure mitochondrial function in CVE cells by using whole, intact cells and a bioanalyzer. A mito-stress assay is used to challenge the cells that have been perturbed, either physically or chemically, and evaluate their bioenergetic function. Additionally, this method also provides a useful way to screen new therapeutics that have direct effects on mitochondrial function. We have optimized the cell density necessary to yield oxygen consumption rates that allow for the calculation of a variety of mitochondrial parameters, including ATP production, maximal respiration, and spare capacity. We also show the sensitivity of the assay by demonstrating that the introduction of the microRNA, miR-34a, leads to a pronounced and detectable decrease in mitochondrial activity. While the data shown in this paper is optimized for the bEnd.3 cell line, we have also optimized the protocol for primary CVE cells, further suggesting the utility in preclinical and clinical models.

  15. Sphingosine 1 Phosphate at the Blood Brain Barrier: Can the Modulation of S1P Receptor 1 Influence the Response of Endothelial Cells and Astrocytes to Inflammatory Stimuli?

    PubMed

    Spampinato, Simona F; Obermeier, Birgit; Cotleur, Anne; Love, Anna; Takeshita, Yukio; Sano, Yasuteru; Kanda, Takashi; Ransohoff, Richard M

    2015-01-01

    The ability of the Blood Brain Barrier (BBB) to maintain proper barrier functions, keeping an optimal environment for central nervous system (CNS) activity and regulating leukocytes' access, can be affected in CNS diseases. Endothelial cells and astrocytes are the principal BBB cellular constituents and their interaction is essential to maintain its function. Both endothelial cells and astrocytes express the receptors for the bioactive sphingolipid S1P. Fingolimod, an immune modulatory drug whose structure is similar to S1P, has been approved for treatment in multiple sclerosis (MS): fingolimod reduces the rate of MS relapses by preventing leukocyte egress from the lymph nodes. Here, we examined the ability of S1P and fingolimod to act on the BBB, using an in vitro co-culture model that allowed us to investigate the effects of S1P on endothelial cells, astrocytes, and interactions between the two. Acting selectively on endothelial cells, S1P receptor signaling reduced cell death induced by inflammatory cytokines. When acting on astrocytes, fingolimod treatment induced the release of a factor, granulocyte macrophage colony-stimulating factor (GM-CSF) that reduced the effects of cytokines on endothelium. In an in vitro BBB model incorporating shear stress, S1P receptor modulation reduced leukocyte migration across the endothelial barrier, indicating a novel mechanism that might contribute to fingolimod efficacy in MS treatment.

  16. Dasatinib-loaded albumin nanoparticles possess diminished endothelial cell barrier disruption and retain potent anti-leukemia cell activity

    PubMed Central

    Li, Zhenyu; Shetty, Sreerama; Fu, Jian

    2016-01-01

    Dasatinib (DAS), a second-generation tyrosine kinase inhibitor, is highly effective in treating chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia. However, its clinical use is limited due to serious adverse effects. DAS can disrupt endothelial barrier integrity and increase endothelial permeability which may cause peripheral edema and pleural effusion. Albumin nanoparticles (NPs) as a drug carrier may serve as a useful tool for cell-selective drug delivery to reduce DAS-induced endothelial hyperpermeability and maintain endothelial barrier integrity. In this study, we reported that DAS-loaded NPs exhibited potent anti-leukemia efficacy as DAS alone. Importantly, albumin NPs as a drug carrier markedly reduced DAS-induced endothelial hyperpermeability by restraining the inhibition of Lyn kinase signaling pathway in endothelial cells. Therefore, albumin NPs could be a potential tool to improve anti-leukemia efficacy of DAS through its cell-selective effects. PMID:27391073

  17. Transient Intervals of Hyper-Gravity Enhance Endothelial Barrier Integrity: Impact of Mechanical and Gravitational Forces Measured Electrically

    PubMed Central

    Szulcek, Robert; van Bezu, Jan; Boonstra, Johannes; van Loon, Jack J. W. A.; van Nieuw Amerongen, Geerten P.

    2015-01-01

    Background Endothelial cells (EC) guard vascular functions by forming a dynamic barrier throughout the vascular system that sensitively adapts to ‘classical’ biomechanical forces, such as fluid shear stress and hydrostatic pressure. Alterations in gravitational forces might similarly affect EC integrity, but remain insufficiently studied. Methods In an unique approach, we utilized Electric Cell-substrate Impedance Sensing (ECIS) in the gravity-simulators at the European Space Agency (ESA) to study dynamic responses of human EC to simulated micro- and hyper-gravity as well as to classical forces. Results Short intervals of micro- or hyper-gravity evoked distinct endothelial responses. Stimulated micro-gravity led to decreased endothelial barrier integrity, whereas hyper-gravity caused sustained barrier enhancement by rapid improvement of cell-cell integrity, evidenced by a significant junctional accumulation of VE-cadherin (p = 0.011), significant enforcement of peripheral F-actin (p = 0.008) and accompanied by a slower enhancement of cell-matrix interactions. The hyper-gravity triggered EC responses were force dependent and nitric-oxide (NO) mediated showing a maximal resistance increase of 29.2±4.8 ohms at 2g and 60.9±6.2 ohms at 4g vs. baseline values that was significantly suppressed by NO blockage (p = 0.011). Conclusion In conclusion, short-term application of hyper-gravity caused a sustained improvement of endothelial barrier integrity, whereas simulated micro-gravity weakened the endothelium. In clear contrast, classical forces of shear stress and hydrostatic pressure induced either short-lived or no changes to the EC barrier. Here, ECIS has proven a powerful tool to characterize subtle and distinct EC gravity-responses due to its high temporal resolution, wherefore ECIS has a great potential for the study of gravity-responses such as in real space flights providing quantitative assessment of a variety of cell biological characteristics of any adherent

  18. Curcumin and Endothelial Function: Evidence and Mechanisms of Protective Effects.

    PubMed

    Karimian, Maryam S; Pirro, Matteo; Johnston, Thomas P; Majeed, Muhammed; Sahebkar, Amirhossein

    2017-01-01

    The endothelium is a large paracrine organ regulating cell growth, vascular tone and thrombogenicity as well as platelet and leukocyte interactions. Endothelial function can be assessed by noninvasive techniques [e.g. flow-mediated vasodilation, nitroglycerin-mediated dilation and pulse wave velocity] and measuring specific circulating biomarkers [cell adhesion molecules, endothelial microparticles and endothelial progenitor cells]. Impaired endothelial function plays a key role in the development of atherosclerosis, arterial hypertension, heart failure, ischemia-reperfusion injury, Alzheimer's disease and other conditions. Endothelial function is also involved in growth and proliferation of tumor cells. We performed a literature review and assessed the role of the natural polyphenol, curcumin, as a potential inexpensive, well-tolerated, and safe agent for improving endothelial function. Curcumin exerts several positive pharmacological effects; these include anti-inflammatory, antioxidant, anti-hypertensive, anti-cancer, antiviral, anti-infective and wound-healing properties. Specifically, curcumin's anti-inflammatory effects are thought to be caused by reducing trans-endothelial monocyte migration by reduction of mRNA and protein expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and P-selectin and by modulating NFκB, JNK, p38 and STAT-3 in endothelial cells. Dietary curcumin supplementation can also increase antioxidant activity through the induction of heme oxygenase-1, a scavenger of free radicals, and by reduction of reactive oxygen species and Nox-2. Curcumin appears to improve endothelial function but additional research is needed to determine the precise mechanism(s) and biomarkers involved in curcumin's therapeutic effects on endothelial dysfunction. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  19. Phospholipase C-ε signaling mediates endothelial cell inflammation and barrier disruption in acute lung injury

    PubMed Central

    Bijli, Kaiser M.; Fazal, Fabeha; Slavin, Spencer A.; Leonard, Antony; Grose, Valerie; Alexander, William B.; Smrcka, Alan V.

    2016-01-01

    Phospholipase C-ε (PLC-ε) is a unique PLC isoform that can be regulated by multiple signaling inputs from both Ras family GTPases and heterotrimeric G proteins and has primary sites of expression in the heart and lung. Whereas the role of PLC-ε in cardiac function and pathology has been documented, its relevance in acute lung injury (ALI) is unclear. We used PLC-ε−/− mice to address the role of PLC-ε in regulating lung vascular inflammation and injury in an aerosolized bacterial LPS inhalation mouse model of ALI. PLC-ε−/− mice showed a marked decrease in LPS-induced proinflammatory mediators (ICAM-1, VCAM-1, TNF-α, IL-1β, IL-6, macrophage inflammatory protein 2, keratinocyte-derived cytokine, monocyte chemoattractant protein 1, and granulocyte-macrophage colony-stimulating factor), lung neutrophil infiltration and microvascular leakage, and loss of VE-cadherin compared with PLC-ε+/+ mice. These data identify PLC-ε as a critical determinant of proinflammatory and leaky phenotype of the lung. To test the possibility that PLC-ε activity in endothelial cells (EC) could contribute to ALI, we determined its role in EC inflammation and barrier disruption. RNAi knockdown of PLC-ε inhibited NF-κB activity in response to diverse proinflammatory stimuli, thrombin, LPS, TNF-α, and the nonreceptor agonist phorbol 13-myristate 12-acetate (phorbol esters) in EC. Depletion of PLC-ε also inhibited thrombin-induced expression of NF-κB target gene, VCAM-1. Importantly, PLC-ε knockdown also protected against thrombin-induced EC barrier disruption by inhibiting the loss of VE-cadherin at adherens junctions and formation of actin stress fibers. These data identify PLC-ε as a novel regulator of EC inflammation and permeability and show a hitherto unknown role of PLC-ε in the pathogenesis of ALI. PMID:27371732

  20. Intermittent Hypoxia Impairs Endothelial Function in Early Preatherosclerosis.

    PubMed

    Tuleta, I; França, C N; Wenzel, D; Fleischmann, B; Nickenig, G; Werner, N; Skowasch, D

    2015-01-01

    Intermittent hypoxia seems to be a major pathomechanism of obstructive sleep apnea-associated progression of atherosclerosis. The goal of the present study was to assess the influence of hypoxia on endothelial function depending on the initial stage of vasculopathy. We used 16 ApoE-/- mice were exposed to a 6-week-intermittent hypoxia either immediately (early preatherosclerosis) or after 5 weeks of high-cholesterol diet (advanced preatherosclerosis). Another 16 ApoE-/- mice under normoxia served as corresponding controls. Endothelial function was measured by an organ bath technique. Blood plasma CD31+/annexin V+ endothelial microparticles as well as sca1/flk1+ endothelial progenitor cells in blood and bone marrow were analyzed by flow cytometry. The findings were that intermittent hypoxia impaired endothelial function (56.6±6.2% of maximal phenylephrine-induced vasoconstriction vs. 35.2±4.1% in control) and integrity (increased percentage of endothelial microparticles: 0.28±0.05% vs. 0.15±0.02% in control) in early preatherosclerosis. Peripheral repair capacity expressed as the number of endothelial progenitor cells in blood was attenuated under hypoxia (2.0±0.5% vs. 5.3±1.9% in control), despite the elevated number of these cells in the bone marrow (2.0±0.4% vs. 1.1±0.2% in control). In contrast, endothelial function, as well as microparticle and endothelial progenitor cell levels were similar under hypoxia vs. control in advanced preatherosclerosis. We conclude that hypoxia aggravates endothelial dysfunction and destruction in early preatherosclerosis.

  1. Metformin restores endothelial function in aorta of diabetic rats

    PubMed Central

    Sena, Cristina M; Matafome, Paulo; Louro, Teresa; Nunes, Elsa; Fernandes, Rosa; Seiça, Raquel M

    2011-01-01

    BACKGROUND AND PURPOSE The effects of metformin, an antidiabetic agent that improves insulin sensitivity, on endothelial function have not been fully elucidated. This study was designed to assess the effect of metformin on impaired endothelial function, oxidative stress, inflammation and advanced glycation end products formation in type 2 diabetes mellitus. EXPERIMENTAL APPROACH Goto-Kakizaki (GK) rats, an animal model of nonobese type 2 diabetes, fed with normal and high-fat diet during 4 months were treated with metformin for 4 weeks before evaluation. Systemic oxidative stress, endothelial function, insulin resistance, nitric oxide (NO) bioavailability, glycation and vascular oxidative stress were determined in the aortic rings of the different groups. A pro-inflammatory biomarker the chemokine CCL2 (monocyte chemoattractant protein-1) was also evaluated. KEY RESULTS High-fat fed GK rats with hyperlipidaemia showed increased vascular and systemic oxidative stress and impaired endothelial-dependent vasodilatation. Metformin treatment significantly improved glycation, oxidative stress, CCL2 levels, NO bioavailability and insulin resistance and normalized endothelial function in aorta. CONCLUSION AND IMPLICATIONS Metformin restores endothelial function and significantly improves NO bioavailability, glycation and oxidative stress in normal and high-fat fed GK rats. This supports the concept of the central role of metformin as a first-line therapeutic to treat diabetic patients in order to protect against endothelial dysfunction associated with type 2 diabetes mellitus. PMID:21250975

  2. Arterial endothelial barrier dysfunction: actions of homocysteine and the hypoxanthine-xanthine oxidase free radical generating system.

    PubMed Central

    Berman, R. S.; Martin, W.

    1993-01-01

    1. Endothelial barrier function was assessed by use of an in vitro model in which transfer of trypan blue-labelled albumin was measured across monolayers of bovine aortic endothelial cells grown on polycarbonate membranes. 2. Addition of either hypoxanthine (0.2 mM) or xanthine oxidase (20 mu ml-1) alone during a 90 min incubation did not affect albumin transfer across endothelial cell monolayers, but a combination of both increased transfer. 3. The increase in albumin transfer induced by hypoxanthine and xanthine oxidase was abolished by catalase (3 u ml-1), reduced by allopurinol (4 mM), but unaffected by superoxide dismutase (6000 u ml-1), the hydroxyl radical scavengers, mannitol (15 mM), dimethylthiourea (10 mM) and N-(2-mercaptopropionyl)-glycine (1 mM), the iron chelator, deferoxamine (0.5 mM), ferric chloride (50 microM), an inhibitor of nitric oxide synthase, NG-nitro-L-arginine (30 microM), or the antioxidant, dithiothreitol (3 mM). 4. Hydrogen peroxide (0.1-30 mM) itself increased albumin transfer across endothelial cell monolayers, exhibiting a biphasic concentration-response curve. The increase induced by 0.1 mM hydrogen peroxide was abolished in the presence of 0.3 u ml-1 catalase whilst that induced by 10 mM hydrogen peroxide was abolished by 3000 u ml-1 catalase. 5. Homocysteine (0.5-1.5 mM) did not affect albumin transfer across endothelial monolayers when added alone, but when added in combination with copper sulphate (50 microM), which catalyses its oxidation, a significant increase in albumin transfer was observed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8485631

  3. Poly(I:C) Induces Human Lung Endothelial Barrier Dysfunction by Disrupting Tight Junction Expression of Claudin-5

    DOE PAGES

    Huang, Li -Yun; Stuart, Christine; Takeda, Kazuyo; ...

    2016-08-09

    Viral infections are often accompanied by pulmonary microvascular leakage and vascular endothelial dysfunction via mechanisms that are not completely defined. Here, we investigated the effect of the Toll-like receptor 3 (TLR3) ligand polyinosinic-polycytidylic acid [Poly(I:C)], a synthetic analog of viral double-stranded RNA (dsRNA) commonly used to simulate viral infections, on the barrier function and tight junction integrity of primary human lung microvascular endothelial cells. Poly(I:C) stimulated IL-6, IL-8, TNFα, and IFNβ production in conjunction with the activation of NF-κB and IRF3 confirming the Poly(I:C)-responsiveness of these cells. Poly(I:C) increased endothelialmonolayer permeability with a corresponding dose- and time-dependent decrease in themore » expression of claudin-5, a transmembrane tight junction protein and reduction of CLDN5 mRNA levels. Immunofluorescence experiments revealed disappearance of membrane-associated claudin-5 and co-localization of cytoplasmic claudin-5 with lysosomal-associated membrane protein 1. Chloroquine and Bay11-7082, inhibitors of TLR3 and NF-κB signaling, respectively, protected against the loss of claudin-5. Altogether, these findings provide new insight on how dsRNA-activated signaling pathways may disrupt vascular endothelial function and contribute to vascular leakage pathologies.« less

  4. Poly(I:C) Induces Human Lung Endothelial Barrier Dysfunction by Disrupting Tight Junction Expression of Claudin-5

    SciTech Connect

    Huang, Li -Yun; Stuart, Christine; Takeda, Kazuyo; D’Agnillo, Felice; Golding, Basil; Deli, Mária A.

    2016-08-09

    Viral infections are often accompanied by pulmonary microvascular leakage and vascular endothelial dysfunction via mechanisms that are not completely defined. Here, we investigated the effect of the Toll-like receptor 3 (TLR3) ligand polyinosinic-polycytidylic acid [Poly(I:C)], a synthetic analog of viral double-stranded RNA (dsRNA) commonly used to simulate viral infections, on the barrier function and tight junction integrity of primary human lung microvascular endothelial cells. Poly(I:C) stimulated IL-6, IL-8, TNFα, and IFNβ production in conjunction with the activation of NF-κB and IRF3 confirming the Poly(I:C)-responsiveness of these cells. Poly(I:C) increased endothelialmonolayer permeability with a corresponding dose- and time-dependent decrease in the expression of claudin-5, a transmembrane tight junction protein and reduction of CLDN5 mRNA levels. Immunofluorescence experiments revealed disappearance of membrane-associated claudin-5 and co-localization of cytoplasmic claudin-5 with lysosomal-associated membrane protein 1. Chloroquine and Bay11-7082, inhibitors of TLR3 and NF-κB signaling, respectively, protected against the loss of claudin-5. Altogether, these findings provide new insight on how dsRNA-activated signaling pathways may disrupt vascular endothelial function and contribute to vascular leakage pathologies.

  5. In vitro models of the blood–brain barrier: An overview of commonly used brain endothelial cell culture models and guidelines for their use

    PubMed Central

    Helms, Hans C; Abbott, N Joan; Burek, Malgorzata; Cecchelli, Romeo; Couraud, Pierre-Olivier; Deli, Maria A; Förster, Carola; Galla, Hans J; Romero, Ignacio A; Shusta, Eric V; Stebbins, Matthew J; Vandenhaute, Elodie; Weksler, Babette

    2016-01-01

    The endothelial cells lining the brain capillaries separate the blood from the brain parenchyma. The endothelial monolayer of the brain capillaries serves both as a crucial interface for exchange of nutrients, gases, and metabolites between blood and brain, and as a barrier for neurotoxic components of plasma and xenobiotics. This “blood-brain barrier” function is a major hindrance for drug uptake into the brain parenchyma. Cell culture models, based on either primary cells or immortalized brain endothelial cell lines, have been developed, in order to facilitate in vitro studies of drug transport to the brain and studies of endothelial cell biology and pathophysiology. In this review, we aim to give an overview of established in vitro blood–brain barrier models with a focus on their validation regarding a set of well-established blood–brain barrier characteristics. As an ideal cell culture model of the blood–brain barrier is yet to be developed, we also aim to give an overview of the advantages and drawbacks of the different models described. PMID:26868179

  6. Lipopolysaccharide-induced pulmonary endothelial barrier disruption and lung edema: critical role for bicarbonate stimulation of AC10.

    PubMed

    Nickols, Jordan; Obiako, Boniface; Ramila, K C; Putinta, Kevin; Schilling, Sarah; Sayner, Sarah L

    2015-12-15

    Bacteria-induced sepsis is a common cause of pulmonary endothelial barrier dysfunction and can progress toward acute respiratory distress syndrome. Elevations in intracellular cAMP tightly regulate pulmonary endothelial barrier integrity; however, cAMP signals are highly compartmentalized: whether cAMP is barrier-protective or -disruptive depends on the compartment (plasma membrane or cytosol, respectively) in which the signal is generated. The mammalian soluble adenylyl cyclase isoform 10 (AC10) is uniquely stimulated by bicarbonate and is expressed in pulmonary microvascular endothelial cells (PMVECs). Elevated extracellular bicarbonate increases cAMP in PMVECs to disrupt the endothelial barrier and increase the filtration coefficient (Kf) in the isolated lung. We tested the hypothesis that sepsis-induced endothelial barrier disruption and increased permeability are dependent on extracellular bicarbonate and activation of AC10. Our findings reveal that LPS-induced endothelial barrier disruption is dependent on extracellular bicarbonate: LPS-induced barrier failure and increased permeability are exacerbated in elevated bicarbonate compared with low extracellular bicarbonate. The AC10 inhibitor KH7 attenuated the bicarbonate-dependent LPS-induced barrier disruption. In the isolated lung, LPS failed to increase Kf in the presence of minimal perfusate bicarbonate. An increase in perfusate bicarbonate to the physiological range (24 mM) revealed the LPS-induced increase in Kf, which was attenuated by KH7. Furthermore, in PMVECs treated with LPS for 6 h, there was a dose-dependent increase in AC10 expression. Thus these findings reveal that LPS-induced pulmonary endothelial barrier failure requires bicarbonate activation of AC10. Copyright © 2015 the American Physiological Society.

  7. Lipopolysaccharide-induced pulmonary endothelial barrier disruption and lung edema: critical role for bicarbonate stimulation of AC10

    PubMed Central

    Nickols, Jordan; Obiako, Boniface; Ramila, K. C.; Putinta, Kevin; Schilling, Sarah

    2015-01-01

    Bacteria-induced sepsis is a common cause of pulmonary endothelial barrier dysfunction and can progress toward acute respiratory distress syndrome. Elevations in intracellular cAMP tightly regulate pulmonary endothelial barrier integrity; however, cAMP signals are highly compartmentalized: whether cAMP is barrier-protective or -disruptive depends on the compartment (plasma membrane or cytosol, respectively) in which the signal is generated. The mammalian soluble adenylyl cyclase isoform 10 (AC10) is uniquely stimulated by bicarbonate and is expressed in pulmonary microvascular endothelial cells (PMVECs). Elevated extracellular bicarbonate increases cAMP in PMVECs to disrupt the endothelial barrier and increase the filtration coefficient (Kf) in the isolated lung. We tested the hypothesis that sepsis-induced endothelial barrier disruption and increased permeability are dependent on extracellular bicarbonate and activation of AC10. Our findings reveal that LPS-induced endothelial barrier disruption is dependent on extracellular bicarbonate: LPS-induced barrier failure and increased permeability are exacerbated in elevated bicarbonate compared with low extracellular bicarbonate. The AC10 inhibitor KH7 attenuated the bicarbonate-dependent LPS-induced barrier disruption. In the isolated lung, LPS failed to increase Kf in the presence of minimal perfusate bicarbonate. An increase in perfusate bicarbonate to the physiological range (24 mM) revealed the LPS-induced increase in Kf, which was attenuated by KH7. Furthermore, in PMVECs treated with LPS for 6 h, there was a dose-dependent increase in AC10 expression. Thus these findings reveal that LPS-induced pulmonary endothelial barrier failure requires bicarbonate activation of AC10. PMID:26475732

  8. Effects of diabetic HDL on endothelial cell function.

    PubMed

    He, Dan; Pan, Bing; Ren, Hui; Zheng, Lemin

    2014-01-01

    Type 2 diabetes mellitus (T2DM) is accompanied by dysfunctional high-density lipoprotein (HDL) and this is characterized by alterations in its composition and structure compared with HDL from normal subjects (N-HDL). HDL from diabetic subjects (D-HDL) has a diminished endothelial protective capacity including reducted ability to exert antioxidative activity, stimulate endothelial cell (EC) production of nitric oxide (NO) and endothelium-dependent vasomotion, promote endothelial progenitor cell (EPC)-mediated endothelial repair. In addition, D-HDL promotes EC proliferation, migration and adhesion to the matrix. The present review provides an overview of these effects of diabetic HDL on EC function, as well as the possible changes of D-HDL structure and composition which may be responsible for the diminished endothelial protective capacity of D-HDL.

  9. Long Noncoding RNA MANTIS Facilitates Endothelial Angiogenic Function.

    PubMed

    Leisegang, Matthias S; Fork, Christian; Josipovic, Ivana; Richter, Florian Martin; Preussner, Jens; Hu, Jiong; Miller, Matthew J; Epah, Jeremy; Hofmann, Patrick; Günther, Stefan; Moll, Franziska; Valasarajan, Chanil; Heidler, Juliana; Ponomareva, Yuliya; Freiman, Thomas M; Maegdefessel, Lars; Plate, Karl H; Mittelbronn, Michel; Uchida, Shizuka; Künne, Carsten; Stellos, Konstantinos; Schermuly, Ralph T; Weissmann, Norbert; Devraj, Kavi; Wittig, Ilka; Boon, Reinier A; Dimmeler, Stefanie; Pullamsetti, Soni Savai; Looso, Mario; Miller, Francis J; Brandes, Ralf P

    2017-07-04

    The angiogenic function of endothelial cells is regulated by numerous mechanisms, but the impact of long noncoding RNAs (lncRNAs) has hardly been studied. We set out to identify novel and functionally important endothelial lncRNAs. Epigenetically controlled lncRNAs in human umbilical vein endothelial cells were searched by exon-array analysis after knockdown of the histone demethylase JARID1B. Molecular mechanisms were investigated by RNA pulldown and immunoprecipitation, mass spectrometry, microarray, several knockdown approaches, CRISPR-Cas9, assay for transposase-accessible chromatin sequencing, and chromatin immunoprecipitation in human umbilical vein endothelial cells. Patient samples from lung and tumors were studied for MANTIS expression. A search for epigenetically controlled endothelial lncRNAs yielded lncRNA n342419, here termed MANTIS, as the most strongly regulated lncRNA. Controlled by the histone demethylase JARID1B, MANTIS was downregulated in patients with idiopathic pulmonary arterial hypertension and in rats treated with monocrotaline, whereas it was upregulated in carotid arteries of Macaca fascicularis subjected to atherosclerosis regression diet, and in endothelial cells isolated from human glioblastoma patients. CRISPR/Cas9-mediated deletion or silencing of MANTIS with small interfering RNAs or GapmeRs inhibited angiogenic sprouting and alignment of endothelial cells in response to shear stress. Mechanistically, the nuclear-localized MANTIS lncRNA interacted with BRG1, the catalytic subunit of the switch/sucrose nonfermentable chromatin-remodeling complex. This interaction was required for nucleosome remodeling by keeping the ATPase function of BRG1 active. Thereby, the transcription of key endothelial genes such as SOX18, SMAD6, and COUP-TFII was regulated by ensuring efficient RNA polymerase II machinery binding. MANTIS is a differentially regulated novel lncRNA facilitating endothelial angiogenic function. © 2017 The Authors.

  10. Long Noncoding RNA MANTIS Facilitates Endothelial Angiogenic Function

    PubMed Central

    Leisegang, Matthias S.; Fork, Christian; Josipovic, Ivana; Richter, Florian Martin; Preussner, Jens; Hu, Jiong; Miller, Matthew J.; Epah, Jeremy; Hofmann, Patrick; Günther, Stefan; Moll, Franziska; Valasarajan, Chanil; Heidler, Juliana; Ponomareva, Yuliya; Freiman, Thomas M.; Maegdefessel, Lars; Plate, Karl H.; Mittelbronn, Michel; Uchida, Shizuka; Künne, Carsten; Stellos, Konstantinos; Schermuly, Ralph T.; Weissmann, Norbert; Devraj, Kavi; Wittig, Ilka; Boon, Reinier A.; Dimmeler, Stefanie; Pullamsetti, Soni Savai; Looso, Mario; Miller, Francis J.

    2017-01-01

    Background: The angiogenic function of endothelial cells is regulated by numerous mechanisms, but the impact of long noncoding RNAs (lncRNAs) has hardly been studied. We set out to identify novel and functionally important endothelial lncRNAs. Methods: Epigenetically controlled lncRNAs in human umbilical vein endothelial cells were searched by exon-array analysis after knockdown of the histone demethylase JARID1B. Molecular mechanisms were investigated by RNA pulldown and immunoprecipitation, mass spectrometry, microarray, several knockdown approaches, CRISPR-Cas9, assay for transposase-accessible chromatin sequencing, and chromatin immunoprecipitation in human umbilical vein endothelial cells. Patient samples from lung and tumors were studied for MANTIS expression. Results: A search for epigenetically controlled endothelial lncRNAs yielded lncRNA n342419, here termed MANTIS, as the most strongly regulated lncRNA. Controlled by the histone demethylase JARID1B, MANTIS was downregulated in patients with idiopathic pulmonary arterial hypertension and in rats treated with monocrotaline, whereas it was upregulated in carotid arteries of Macaca fascicularis subjected to atherosclerosis regression diet, and in endothelial cells isolated from human glioblastoma patients. CRISPR/Cas9-mediated deletion or silencing of MANTIS with small interfering RNAs or GapmeRs inhibited angiogenic sprouting and alignment of endothelial cells in response to shear stress. Mechanistically, the nuclear-localized MANTIS lncRNA interacted with BRG1, the catalytic subunit of the switch/sucrose nonfermentable chromatin-remodeling complex. This interaction was required for nucleosome remodeling by keeping the ATPase function of BRG1 active. Thereby, the transcription of key endothelial genes such as SOX18, SMAD6, and COUP-TFII was regulated by ensuring efficient RNA polymerase II machinery binding. Conclusion: MANTIS is a differentially regulated novel lncRNA facilitating endothelial angiogenic

  11. The function of vascular endothelial growth factor.

    PubMed

    Nieves, Bonnie J; D'Amore, Patricia A; Bryan, Brad A

    2009-01-01

    Vascular endothelial growth factor (VEGF) is considered the master regulator of angiogenesis during growth and development, as well as in disease states such as cancer, diabetes, and macular degeneration. This review details our current understanding of VEGF signaling and discusses the benefits and unexpected side effects of promising anti-angiogenic therapeutics that are currently being used to inhibit neovacularization in tumors.

  12. Barrier function of airway tract epithelium

    PubMed Central

    Ganesan, Shyamala; Comstock, Adam T; Sajjan, Uma S

    2013-01-01

    Airway epithelium contributes significantly to the barrier function of airway tract. Mucociliary escalator, intercellular apical junctional complexes which regulate paracellular permeability and antimicrobial peptides secreted by the airway epithelial cells are the three primary components of barrier function of airway tract. These three components act cooperatively to clear inhaled pathogens, allergens and particulate matter without inducing inflammation and maintain tissue homeostasis. Therefore impairment of one or more of these essential components of barrier function may increase susceptibility to infection and promote exaggerated and prolonged innate immune responses to environmental factors including allergens and pathogens resulting in chronic inflammation. Here we review the regulation of components of barrier function with respect to chronic airways diseases. PMID:24665407

  13. Asef mediates HGF protective effects against LPS-induced lung injury and endothelial barrier dysfunction.

    PubMed

    Meng, Fanyong; Meliton, Angelo; Moldobaeva, Nurgul; Mutlu, Gokhan; Kawasaki, Yoshihiro; Akiyama, Tetsu; Birukova, Anna A

    2015-03-01

    Increased vascular endothelial permeability and inflammation are major pathological mechanisms of pulmonary edema and its life-threatening complication, the acute respiratory distress syndrome (ARDS). We have previously described potent protective effects of hepatocyte growth factor (HGF) against thrombin-induced hyperpermeability and identified the Rac pathway as a key mechanism of HGF-mediated endothelial barrier protection. However, anti-inflammatory effects of HGF are less understood. This study examined effects of HGF on the pulmonary endothelial cell (EC) inflammatory activation and barrier dysfunction caused by the gram-negative bacterial pathogen lipopolysaccharide (LPS). We tested involvement of the novel Rac-specific guanine nucleotide exchange factor Asef in the HGF anti-inflammatory effects. HGF protected the pulmonary EC monolayer against LPS-induced hyperpermeability, disruption of monolayer integrity, activation of NF-kB signaling, expression of adhesion molecules intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, and production of IL-8. These effects were critically dependent on Asef. Small-interfering RNA-induced downregulation of Asef attenuated HGF protective effects against LPS-induced EC barrier failure. Protective effects of HGF against LPS-induced lung inflammation and vascular leak were also diminished in Asef knockout mice. Taken together, these results demonstrate potent anti-inflammatory effects by HGF and delineate a key role of Asef in the mediation of the HGF barrier protective and anti-inflammatory effects. Modulation of Asef activity may have important implications in therapeutic strategies aimed at the treatment of sepsis and acute lung injury/ARDS-induced gram-negative bacterial pathogens.

  14. Atrial natriuretic peptide protects against Staphylococcus aureus-induced lung injury and endothelial barrier dysfunction

    PubMed Central

    Xing, Junjie; Moldobaeva, Nurgul

    2011-01-01

    Lung inflammation and alterations in endothelial cell (EC) permeability are key events to development of acute lung injury (ALI). Protective effects of atrial natriuretic peptide (ANP) have been shown against inflammatory signaling and endothelial barrier dysfunction induced by gram-negative bacterial wall liposaccharide. We hypothesized that ANP may possess more general protective effects and attenuate lung inflammation and EC barrier dysfunction by suppressing inflammatory cascades and barrier-disruptive mechanisms shared by gram-negative and gram-positive pathogens. C57BL/6J wild-type or ANP knockout mice (Nppa−/−) were treated with gram-positive bacterial cell wall compounds, Staphylococcus aureus-derived peptidoglycan (PepG) and/or lipoteichoic acid (LTA) (intratracheal, 2.5 mg/kg each), with or without ANP (intravenous, 2 μg/kg). In vitro, human pulmonary EC barrier properties were assessed by morphological analysis of gap formation and measurements of transendothelial electrical resistance. LTA and PepG markedly increased pulmonary EC permeability and activated p38 and ERK1/2 MAP kinases, NF-κB, and Rho/Rho kinase signaling. EC barrier dysfunction was further elevated upon combined LTA and PepG treatment, but abolished by ANP pretreatment. In vivo, LTA and PepG-induced accumulation of protein and cells in the bronchoalveolar lavage fluid, tissue neutrophil infiltration, and increased Evans blue extravasation in the lungs was significantly attenuated by intravenous injection of ANP. Accumulation of bronchoalveolar lavage markers of LTA/PepG-induced lung inflammation and barrier dysfunction was further augmented in ANP−/− mice and attenuated by exogenous ANP injection. These results strongly suggest a protective role of ANP in the in vitro and in vivo models of ALI associated with gram-positive infection. Thus ANP may have important implications in therapeutic strategies aimed at the treatment of sepsis and ALI-induced gram-positive bacterial

  15. Insulin transcriptionally regulates argininosuccinate synthase to maintain vascular endothelial function.

    PubMed

    Haines, Ricci J; Corbin, Karen D; Pendleton, Laura C; Meininger, Cynthia J; Eichler, Duane C

    2012-04-27

    Diminished vascular endothelial cell nitric oxide (NO) production is a major factor in the complex pathogenesis of diabetes mellitus. In this report, we demonstrate that insulin not only maintains endothelial NO production through regulation of endothelial nitric oxide synthase (eNOS), but also via the regulation of argininosuccinate synthase (AS), which is the rate-limiting step of the citrulline-NO cycle. Using serum starved, cultured vascular endothelial cells, we show that insulin up-regulates AS and eNOS transcription to support NO production. Moreover, we show that insulin enhances NO production in response to physiological cues such as bradykinin. To translate these results to an in vivo model, we show that AS transcription is diminished in coronary endothelial cells isolated from rats with streptozotocin (STZ)-induced diabetes. Importantly, we demonstrate restoration of AS and eNOS transcription by insulin treatment in STZ-diabetic rats, and show that this restoration was accompanied by improved endothelial function as measured by endothelium-dependent vasorelaxation. Overall, this report demonstrates, both in cell culture and whole animal studies, that insulin maintains vascular function, in part, through the maintenance of AS transcription, thus ensuring an adequate supply of arginine to maintain vascular endothelial response to physiological cues. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Galectin-1 suppresses methamphetamine induced neuroinflammation in human brain microvascular endothelial cells: Neuroprotective role in maintaining blood brain barrier integrity.

    PubMed

    Parikh, Neil U; Aalinkeel, R; Reynolds, J L; Nair, B B; Sykes, D E; Mammen, M J; Schwartz, S A; Mahajan, S D

    2015-10-22

    Methamphetamine (Meth) abuse can lead to the breakdown of the blood-brain barrier (BBB) integrity leading to compromised CNS function. The role of Galectins in the angiogenesis process in tumor-associated endothelial cells (EC) is well established; however no data are available on the expression of Galectins in normal human brain microvascular endothelial cells and their potential role in maintaining BBB integrity. We evaluated the basal gene/protein expression levels of Galectin-1, -3 and -9 in normal primary human brain microvascular endothelial cells (BMVEC) that constitute the BBB and examined whether Meth altered Galectin expression in these cells, and if Galectin-1 treatment impacted the integrity of an in-vitro BBB. Our results showed that BMVEC expressed significantly higher levels of Galectin-1 as compared to Galectin-3 and -9. Meth treatment increased Galectin-1 expression in BMVEC. Meth induced decrease in TJ proteins ZO-1, Claudin-3 and adhesion molecule ICAM-1 was reversed by Galectin-1. Our data suggests that Galectin-1 is involved in BBB remodeling and can increase levels of TJ proteins ZO-1 and Claudin-3 and adhesion molecule ICAM-1 which helps maintain BBB tightness thus playing a neuroprotective role. Galectin-1 is thus an important regulator of immune balance from neurodegeneration to neuroprotection, which makes it an important therapeutic agent/target in the treatment of drug addiction and other neurological conditions.

  17. Novel Peptide for Attenuation of Hyperoxia-induced Disruption of Lung Endothelial Barrier and Pulmonary Edema via Modulating Peroxynitrite Formation*

    PubMed Central

    Kondrikov, Dmitry; Gross, Christine; Black, Stephen M.; Su, Yunchao

    2014-01-01

    Pulmonary damages of oxygen toxicity include vascular leakage and pulmonary edema. We have previously reported that hyperoxia increases the formation of NO and peroxynitrite in lung endothelial cells via increased interaction of endothelial nitric oxide (eNOS) with β-actin. A peptide (P326TAT) with amino acid sequence corresponding to the actin binding region of eNOS residues 326–333 has been shown to reduce the hyperoxia-induced formation of NO and peroxynitrite in lung endothelial cells. In the present study, we found that exposure of pulmonary artery endothelial cells to hyperoxia (95% oxygen and 5% CO2) for 48 h resulted in disruption of monolayer barrier integrity in two phases, and apoptosis occurred in the second phase. NOS inhibitor NG-nitro-l-arginine methyl ester attenuated the endothelial barrier disruption in both phases. Peroxynitrite scavenger uric acid did not affect the first phase but ameliorated the second phase of endothelial barrier disruption and apoptosis. P326TAT inhibited hyperoxia-induced disruption of monolayer barrier integrity in two phases and apoptosis in the second phase. More importantly, injection of P326TAT attenuated vascular leakage, pulmonary edema, and endothelial apoptosis in the lungs of mice exposed to hyperoxia. P326TAT also significantly reduced the increase in eNOS-β-actin association and protein tyrosine nitration. Together, these results indicate that peptide P326TAT ameliorates barrier dysfunction of hyperoxic lung endothelial monolayer and attenuates eNOS-β-actin association, peroxynitrite formation, endothelial apoptosis, and pulmonary edema in lungs of hyperoxic mice. P326TAT can be a novel therapeutic agent to treat or prevent acute lung injury in oxygen toxicity. PMID:25315770

  18. Circulating humanin levels are associated with preserved coronary endothelial function

    PubMed Central

    Widmer, R. J.; Flammer, A. J.; Herrmann, J.; Rodriguez-Porcel, M.; Wan, J.; Cohen, P.; Lerman, L. O.

    2013-01-01

    Humanin is a small endogenous antiapoptotic peptide, originally identified as protective against Alzheimer's disease, but subsequently also found on human endothelium as well as carotid artery plaques. Endothelial dysfunction is a precursor to the development of atherosclerotic plaques, which are characterized by a highly proinflammatory, reactive oxygen species, and apoptotic milieu. Previous animal studies demonstrated that humanin administration may improve endothelial function. Thus the aim of this study was to test the hypothesis that patients with coronary endothelial dysfunction have reduced systemic levels of humanin. Forty patients undergoing coronary angiography and endothelial function testing were included and subsequently divided into two groups based on coronary blood flow (CBF) response to intracoronary acetylcholine (normal ≥ 50% increase from baseline, n = 20 each). Aortic plasma samples were obtained at the time of catheterization for the analysis of humanin levels and traditional biomarkers of atherosclerosis including C-reactive protein, Lp-Pla2, and homocysteine. Baseline characteristics were similar in both groups. Patients with coronary endothelial dysfunction (change in CBF = −33 ± 25%) had significantly lower humanin levels (1.3 ± 1.1 vs. 2.2 ± 1.5 ng/ml, P = 0.03) compared with those with normal coronary endothelial function (change in CBF = 194 ± 157%). There was a significant and positive correlation between improved CBF and humanin levels (P = 0.0091) not seen with changes in coronary flow reserve (P = 0.76). C-reactive protein, Lp-Pla2, and homocysteine were not associated with humanin levels. Thus we observed that preserved human coronary endothelial function is uniquely associated with higher systemic humanin levels, introducing a potential diagnostic and/or therapeutic target for patients with coronary endothelial function. PMID:23220334

  19. ZO-1 controls endothelial adherens junctions, cell–cell tension, angiogenesis, and barrier formation

    PubMed Central

    Tornavaca, Olga; Chia, Minghao; Dufton, Neil; Almagro, Lourdes Osuna; Conway, Daniel E.; Randi, Anna M.; Schwartz, Martin A.; Matter, Karl

    2015-01-01

    Intercellular junctions are crucial for mechanotransduction, but whether tight junctions contribute to the regulation of cell–cell tension and adherens junctions is unknown. Here, we demonstrate that the tight junction protein ZO-1 regulates tension acting on VE-cadherin–based adherens junctions, cell migration, and barrier formation of primary endothelial cells, as well as angiogenesis in vitro and in vivo. ZO-1 depletion led to tight junction disruption, redistribution of active myosin II from junctions to stress fibers, reduced tension on VE-cadherin and loss of junctional mechanotransducers such as vinculin and PAK2, and induced vinculin dissociation from the α-catenin–VE-cadherin complex. Claudin-5 depletion only mimicked ZO-1 effects on barrier formation, whereas the effects on mechanotransducers were rescued by inhibition of ROCK and phenocopied by JAM-A, JACOP, or p114RhoGEF down-regulation. ZO-1 was required for junctional recruitment of JACOP, which, in turn, recruited p114RhoGEF. ZO-1 is thus a central regulator of VE-cadherin–dependent endothelial junctions that orchestrates the spatial actomyosin organization, tuning cell–cell tension, migration, angiogenesis, and barrier formation. PMID:25753039

  20. ZO-1 controls endothelial adherens junctions, cell-cell tension, angiogenesis, and barrier formation.

    PubMed

    Tornavaca, Olga; Chia, Minghao; Dufton, Neil; Almagro, Lourdes Osuna; Conway, Daniel E; Randi, Anna M; Schwartz, Martin A; Matter, Karl; Balda, Maria S

    2015-03-16

    Intercellular junctions are crucial for mechanotransduction, but whether tight junctions contribute to the regulation of cell-cell tension and adherens junctions is unknown. Here, we demonstrate that the tight junction protein ZO-1 regulates tension acting on VE-cadherin-based adherens junctions, cell migration, and barrier formation of primary endothelial cells, as well as angiogenesis in vitro and in vivo. ZO-1 depletion led to tight junction disruption, redistribution of active myosin II from junctions to stress fibers, reduced tension on VE-cadherin and loss of junctional mechanotransducers such as vinculin and PAK2, and induced vinculin dissociation from the α-catenin-VE-cadherin complex. Claudin-5 depletion only mimicked ZO-1 effects on barrier formation, whereas the effects on mechanotransducers were rescued by inhibition of ROCK and phenocopied by JAM-A, JACOP, or p114RhoGEF down-regulation. ZO-1 was required for junctional recruitment of JACOP, which, in turn, recruited p114RhoGEF. ZO-1 is thus a central regulator of VE-cadherin-dependent endothelial junctions that orchestrates the spatial actomyosin organization, tuning cell-cell tension, migration, angiogenesis, and barrier formation.

  1. Effect of moisturizers on epidermal barrier function.

    PubMed

    Lodén, Marie

    2012-01-01

    A daily moisturizing routine is a vital part of the management of patients with atopic dermatitis and other dry skin conditions. The composition of the moisturizer determines whether the treatment strengthens or deteriorates the skin barrier function, which may have consequences for the outcome of the dermatitis. One might expect that a patient's impaired skin barrier function should improve in association with a reduction in the clinical signs of dryness. Despite visible relief of the dryness symptoms, however, the abnormal transepidermal water loss has been reported to remain high, or even to increase under certain regimens, whereas other moisturizers improve skin barrier function. Differing outcomes have also been reported in healthy skin: some moisturizers produce deterioration in skin barrier function and others improve the skin. Possible targets for barrier-influencing moisturizing creams include the intercellular lipid bilayers, where the fraction of lipids forming a fluid phase might be changed due to compositional or organizational changes. Other targets are the projected size of the corneocytes or the thickness of the stratum corneum. Moisturizers with barrier-improving properties may delay relapse of dermatitis in patients with atopic dermatitis. In a worst-case scenario, treatment with moisturizing creams could increase the risks of dermatitis and asthma. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Diverse Functions of Endothelial NO Synthases System: NO and EDH

    PubMed Central

    Godo, Shigeo

    2016-01-01

    Abstract: Endothelium-dependent relaxations are predominantly regulated by nitric oxide (NO) in large conduit arteries and by endothelium-dependent hyperpolarization (EDH) in small resistance vessels. Although the nature of EDH factors varies depending on species and vascular beds, we have previously demonstrated that endothelial NO synthases (eNOS)-derived hydrogen peroxide (H2O2) is an EDH factor in animals and humans. This vessel size-dependent contribution of NO and EDH is, at least in part, attributable to the diverse roles of endothelial NOSs system; in large conduit arteries, eNOS mainly serves as a NO-generating system to elicit soluble guanylate cyclase–cyclic guanosine monophosphate-mediated relaxations, whereas in small resistance vessels, it serves as a superoxide-generating system to cause EDH/H2O2-mediated relaxations. Endothelial caveolin-1 may play an important role for the diverse roles of NOSs. Although reactive oxygen species are generally regarded harmful, the physiological roles of H2O2 have attracted much attention as accumulating evidence has shown that endothelium-derived H2O2 contributes to cardiovascular homeostasis. The diverse functions of endothelial NOSs system with NO and EDH/H2O2 could account for a compensatory mechanism in the setting of endothelial dysfunction. In this review, we will briefly summarize the current knowledge on the diverse functions of endothelial NOSs system: NO and EDH/H2O2. PMID:26647119

  3. Diverse Functions of Endothelial NO Synthases System: NO and EDH.

    PubMed

    Shimokawa, Hiroaki; Godo, Shigeo

    2016-05-01

    Endothelium-dependent relaxations are predominantly regulated by nitric oxide (NO) in large conduit arteries and by endothelium-dependent hyperpolarization (EDH) in small resistance vessels. Although the nature of EDH factors varies depending on species and vascular beds, we have previously demonstrated that endothelial NO synthases (eNOS)-derived hydrogen peroxide (H2O2) is an EDH factor in animals and humans. This vessel size-dependent contribution of NO and EDH is, at least in part, attributable to the diverse roles of endothelial NOSs system; in large conduit arteries, eNOS mainly serves as a NO-generating system to elicit soluble guanylate cyclase-cyclic guanosine monophosphate-mediated relaxations, whereas in small resistance vessels, it serves as a superoxide-generating system to cause EDH/H2O2-mediated relaxations. Endothelial caveolin-1 may play an important role for the diverse roles of NOSs. Although reactive oxygen species are generally regarded harmful, the physiological roles of H2O2 have attracted much attention as accumulating evidence has shown that endothelium-derived H2O2 contributes to cardiovascular homeostasis. The diverse functions of endothelial NOSs system with NO and EDH/H2O2 could account for a compensatory mechanism in the setting of endothelial dysfunction. In this review, we will briefly summarize the current knowledge on the diverse functions of endothelial NOSs system: NO and EDH/H2O2.

  4. Human brain endothelial barrier cells are distinctly less vulnerable to silver nanoparticles toxicity than human blood vessel cells: A cell-specific mechanism of the brain barrier?

    PubMed

    Sokołowska, Paulina; Białkowska, Kamila; Siatkowska, Małgorzata; Rosowski, Marcin; Kucińska, Magdalena; Komorowski, Piotr; Makowski, Krzysztof; Walkowiak, Bogdan

    2017-10-01

    The blood-brain barrier (BBB) constitutes a distinctive and tightly regulated interface between the brain and the peripheral circulation. The objective of studies was to compare responses of human endothelial cells representing the model of blood vessels - EA.hy926 and HUVEC cells and the model of the brain endothelial barrier - HBEC5i cells to silver nanoparticles (SNPs). A contact of SNPs with endothelial cells resulted in a formation of SNP agglomerates. Consequently, the SNPs uptake by endothelial cells affected cell viability and membrane integrity however observed responses were different. Brain endothelial barrier HBEC5i cells were much less vulnerable to SNPs toxicity comparing to EA.hy926 and HUVEC cells. It can be ascribed to the presence of specialized cellular components of the brain barrier, protecting HBEC5i cells against toxic SNPs. Fundamental understanding of SNPs inducing the BBB dysfunction may initiate engineering novel SNPs which are safe for the BBB and thereby safe for the brain. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Intercellular transfer of P-glycoprotein in human blood-brain barrier endothelial cells is increased by histone deacetylase inhibitors

    PubMed Central

    Noack, Andreas; Noack, Sandra; Buettner, Manuela; Naim, Hassan Y.; Löscher, Wolfgang

    2016-01-01

    The blood–brain barrier (BBB) controls the entry of compounds into the brain, thereby regulating brain homeostasis. Efflux transporters such as P-glycoprotein (Pgp) significantly contribute to BBB function. Multiple signaling pathways modulate the expression and activity of Pgp in response to xenobiotics and disease. A non-genetic way of intercellular transfer of Pgp occurs in cancer cells, but whether this also occurs in non-cancer cells such as endothelial cells that form the BBB is not known. A human brain endothelial cell line (hCMEC/D3) was used to study whether cell-to-cell Pgp transfer occurs during co-culturing with Pgp-EGFP expressing hCMEC/D3 cells. The Pgp-EGFP fusion protein was transferred from donor to recipient cells by cell-to-cell contact and Pgp-EGFP enriched vesicles, which were exocytosed by donor cells and endocytosed by adherent recipient cells. Flow cytometry experiments with the Pgp substrate eFLUXX-ID Gold demonstrated that the transferred Pgp is functional in the recipient cells. Exposure of the donor cells with inhibitors of histone deacetylases (HDACs) resulted in an enhanced intercellular Pgp transfer. Non-genetic transfer of a resistance phenotype and its regulation by HDACs is a novel mechanism of altering BBB functionality. This mechanism may have important implications for understanding drug-induced alterations in Pgp expression and activity. PMID:27375084

  6. Endothelial cell laminin isoforms, laminins 8 and 10, play decisive roles in T cell recruitment across the blood-brain barrier in experimental autoimmune encephalomyelitis.

    PubMed

    Sixt, M; Engelhardt, B; Pausch, F; Hallmann, R; Wendler, O; Sorokin, L M

    2001-05-28

    An active involvement of blood-brain barrier endothelial cell basement membranes in development of inflammatory lesions in the central nervous system (CNS) has not been considered to date. Here we investigated the molecular composition and possible function of the extracellular matrix encountered by extravasating T lymphocytes during experimental autoimmune encephalomyelitis (EAE). Endothelial basement membranes contained laminin 8 (alpha4beta1gamma1) and/or 10 (alpha5beta1gamma1) and their expression was influenced by proinflammatory cytokines or angiostatic agents. T cells emigrating into the CNS during EAE encountered two biochemically distinct basement membranes, the endothelial (containing laminins 8 and 10) and the parenchymal (containing laminins 1 and 2) basement membranes. However, inflammatory cuffs occurred exclusively around endothelial basement membranes containing laminin 8, whereas in the presence of laminin 10 no infiltration was detectable. In vitro assays using encephalitogenic T cell lines revealed adhesion to laminins 8 and 10, whereas binding to laminins 1 and 2 could not be induced. Downregulation of integrin alpha6 on cerebral endothelium at sites of T cell infiltration, plus a high turnover of laminin 8 at these sites, suggested two possible roles for laminin 8 in the endothelial basement membrane: one at the level of the endothelial cells resulting in reduced adhesion and, thereby, increased penetrability of the monolayer; and secondly at the level of the T cells providing direct signals to the transmigrating cells.

  7. Effects of irrigation solutions on corneal endothelial function.

    PubMed

    Yagoubi, M I; Armitage, W J; Diamond, J; Easty, D L

    1994-04-01

    Rabbit corneas were perfused in vitro with an irrigation solution for 90 minutes. This was followed by 6 hours of perfusion with tissue culture medium TC199 during which endothelial function was assessed by monitoring rates of swelling during a period of perfusion in the absence of bicarbonate ions, and subsequent rates of thinning when bicarbonate ions were restored to the perfusate. Corneal thickness (measured with an ultrasonic pachymeter) immediately following excision was 401 microns (SD 19, n = 23). During the 90 minute perfusion at 35 degrees C, corneas exposed to balanced salt solution (BSS), Hartmann's solution or 0.9% NaCl (all initially at room temperature) swelled, respectively, at 14 (SD 2.3, n = 4), 11 (SD 2.6, n = 4), and 70 (SD 4.3, n = 4) microns/h. Cold Hartmann's solution (initially at 4 degrees C) caused corneas to swell at 9 (SD 2.3, n = 4) microns/h. On the other hand, corneas perfused with BSS Plus thinned at 9 (SD 3.4, n = 4) microns/h and TC199 with Earle's salts had little effect on thickness. Rates of swelling and thinning during the following assessment perfusion showed no apparent effects of prior exposure to any of the irrigation solutions on the barrier properties or pump function of the endothelium. Despite this, the increased thickness of corneas exposed initially to BSS, cold Hartmann's solution, or 0.9% NaCl was not fully reversed, even by the end of the 6 hour assessment perfusion. In contrast, the swelling observed in corneas exposed to Hartmann's solution at room temperature was reversed and these corneas had returned to their normal thickness by the end of the assessment period. All corneas, even those exposed to 0.9% NaCl, had an intact endothelial mosaic with no evidence of damage or cell loss, although morphological differences in cell shape and the appearance of cell borders were evident compared with freshly isolated cornea.

  8. Overexpression of actin-depolymerizing factor blocks oxidized low-density lipoprotein-induced mouse brain microvascular endothelial cell barrier dysfunction.

    PubMed

    Wang, Jun; Sun, Lu; Si, Yan-Fang; Li, Bao-Min

    2012-12-01

    The aim of present work was to elucidate the role of actin-depolymerizing factor (ADF), an important regulator of actin cytoskeleton, in the oxidized low-density lipoprotein (ox-LDL)-induced blood-brain barrier (BBB) disruption. The primary mouse brain microvascular endothelial cells (MBMECs) were exposed to ox-LDL. Treatment with LDL served as control. It was found that ADF mRNA level and protein expression were decreased when exposed to ox-LDL in MBMECs. Then, we investigated the influence of ADF overexpression on ox-LDL-treated MBMECs. Structurally, overexpression of ADF inhibited ox-LDL-induced F-actin formation. Functionally, overexpression of ADF attenuated ox-LDL-induced disruption of endothelial barrier marked by restoration of transendothelial electrical resistance, permeability of Evans Blue and expression of tight junction-associated proteins including ZO-1 and occludin, and blocked ox-LDL-induced oxidative stress marked by inhibition of reactive oxygen species (ROS) formation and activity of NADPH oxidase and Nox2 expression. However, overexpression of ADF in control cells had no significant effect on endothelial permeability and ROS formation. In conclusion, overexpression of ADF blocks ox-LDL-induced disruption of endothelial barrier. In addition, siRNA-mediated downregulation of ADF expression aggravated ox-LDL-induced disruption of endothelial barrier and ROS formation. These findings identify ADF as a key signaling molecule in the regulation of BBB integrity and suggest that ADF might be used as a target to modulate diseases accompanied by ox-LDL-induced BBB compromise.

  9. Calcium Channel Blockade and Peroxisome Proliferator Activated Receptor γ Agonism Diminish Cognitive Loss and Preserve Endothelial Function During Diabetes Mellitus.

    PubMed

    Jain, Swati; Sharma, B M; Sharma, Bhupesh

    2016-01-01

    Diabetes mellitus is considered as a main risk factor for vascular dementia. In the past, we have reported the induction of vascular dementia (VaD) by experimental diabetes. This study investigates the efficacy of a nifedipine, a calcium channel blocker and pioglitazone in the pharmacological interdiction of pancreatectomy diabetes (PaD) induced vascular endothelial dysfunction and subsequent VaD in rats. Attentional set shifting (ASST) and Morris water-maze (MWM) test were used for assessment of learning and memory. Vascular endothelial function, blood brain barrier permeability, serum glucose, serum nitrite/nitrate, oxidative stress (viz. aortic superoxide anion, brain thiobarbituric acid reactive species and brain glutathione), brain calcium and inflammation (myeloperoxidase) were also estimated. PaD rats have shown impairment of endothelial function, blood brain barrier permeability, learning and memory along with an increase in brain inflammation, oxidative stress and calcium. Administration of nifedipine and pioglitazone significantly attenuated PaD induced impairment of learning, memory, blood brain barrier permeability, endothelial function and biochemical parameters. It may be concluded that nifedipine, a calcium channel blocker may be considered as a potent pharmacological agent for the management of PaD induced endothelial dysfunction and subsequent VaD.

  10. Evaluation of brain-targeted chitosan nanoparticles through blood-brain barrier cerebral microvessel endothelial cells.

    PubMed

    Sahin, Adem; Yoyen-Ermis, Digdem; Caban-Toktas, Secil; Horzum, Utku; Aktas, Yesim; Couvreur, Patrick; Esendagli, Gunes; Capan, Yilmaz

    2017-09-13

    The blood-brain barrier (BBB) is the major problem for the treatment of central nervous system diseases. A previous study from our group showed that the brain-targeted chitosan nanoparticles-loaded with large peptide moieties can rapidly cross the barrier and provide neuroprotection. The present study aims to determine the efficacy of the brain-targeted chitosan nanoparticles' uptake by the human BBB cerebral microvessel endothelial cells (hCMECs) and to investigate the underlying mechanisms for enhanced cellular entry. Fluorescently labelled nanoparticles either conjugated with antibodies recognising human transferrin receptor (anti-TfR mAb) or not were prepared, characterised and their interaction with cerebral endothelial cells was evaluated. The antibody decoration of chitosan nanoparticles significantly increased their entry into hCMEC/D3 cell line. Inhibition of cellular uptake by chlorpromazine indicated that the anti-TfR mAb-conjugated nanoparticles were preferentially cell internalised through receptor-mediated endocytosis pathway. Alternatively, as primarily observed with control chitosan nanoparticles, aggregation of nanoparticles may also have induced macropinocytosis.

  11. Obstructive Sleep Apnoea Syndrome, Endothelial Function and Markers of Endothelialization. Changes after CPAP

    PubMed Central

    Sanchez Armengol, Angeles; Moreno-Luna, Rafael; Caballero-Eraso, Candela; Macher, Hada C.; Villar, Jose; Merino, Ana M; Castell, Javier; Capote, Francisco; Stiefel, Pablo

    2015-01-01

    Study objectives This study tries to assess the endothelial function in vivo using flow-mediated dilatation (FMD) and several biomarkers of endothelium formation/restoration and damage in patients with obstructive sleep apnoea (OSA) syndrome at baseline and after three months with CPAP therapy. Design Observational study, before and after CPAP therapy. Setting and Patients We studied 30 patients with apnoea/hypopnoea index (AHI) >15/h that were compared with themselves after three months of CPAP therapy. FMD was assessed non-invasively in vivo using the Laser-Doppler flowmetry. Circulating cell-free DNA (cf-DNA) and microparticles (MPs) were measured as markers of endothelial damage and the vascular endothelial growth factor (VEGF) was determined as a marker of endothelial restoration process. Measurements and results After three month with CPAP, FMD significantly increased (1072.26 ± 483.21 vs. 1604.38 ± 915.69 PU, p< 0.005) cf-DNA and MPs significantly decreased (187.93 ± 115.81 vs. 121.28 ± 78.98 pg/ml, p<0.01, and 69.60 ± 62.60 vs. 39.82 ± 22.14 U/μL, p<0.05, respectively) and VEGF levels increased (585.02 ± 246.06 vs. 641.11 ± 212.69 pg/ml, p<0.05). These changes were higher in patients with more severe disease. There was a relationship between markers of damage (r = -0.53, p<0.005) but not between markers of damage and restoration, thus suggesting that both types of markers should be measured together. Conclusions CPAP therapy improves FMD. This improvement may be related to an increase of endothelial restoration process and a decrease of endothelial damage. PMID:25815511

  12. Obstructive sleep apnoea syndrome, endothelial function and markers of endothelialization. Changes after CPAP.

    PubMed

    Muñoz-Hernandez, Rocio; Vallejo-Vaz, Antonio J; Sanchez Armengol, Angeles; Moreno-Luna, Rafael; Caballero-Eraso, Candela; Macher, Hada C; Villar, Jose; Merino, Ana M; Castell, Javier; Capote, Francisco; Stiefel, Pablo

    2015-01-01

    This study tries to assess the endothelial function in vivo using flow-mediated dilatation (FMD) and several biomarkers of endothelium formation/restoration and damage in patients with obstructive sleep apnoea (OSA) syndrome at baseline and after three months with CPAP therapy. Observational study, before and after CPAP therapy. We studied 30 patients with apnoea/hypopnoea index (AHI) >15/h that were compared with themselves after three months of CPAP therapy. FMD was assessed non-invasively in vivo using the Laser-Doppler flowmetry. Circulating cell-free DNA (cf-DNA) and microparticles (MPs) were measured as markers of endothelial damage and the vascular endothelial growth factor (VEGF) was determined as a marker of endothelial restoration process. After three month with CPAP, FMD significantly increased (1072.26 ± 483.21 vs. 1604.38 ± 915.69 PU, p< 0.005) cf-DNA and MPs significantly decreased (187.93 ± 115.81 vs. 121.28 ± 78.98 pg/ml, p<0.01, and 69.60 ± 62.60 vs. 39.82 ± 22.14 U/μL, p<0.05, respectively) and VEGF levels increased (585.02 ± 246.06 vs. 641.11 ± 212.69 pg/ml, p<0.05). These changes were higher in patients with more severe disease. There was a relationship between markers of damage (r = -0.53, p<0.005) but not between markers of damage and restoration, thus suggesting that both types of markers should be measured together. CPAP therapy improves FMD. This improvement may be related to an increase of endothelial restoration process and a decrease of endothelial damage.

  13. Platelet endothelial cell adhesion molecule-1 mediates endothelial-cardiomyocyte communication and regulates cardiac function.

    PubMed

    McCormick, Margaret E; Collins, Caitlin; Makarewich, Catherine A; Chen, Zhongming; Rojas, Mauricio; Willis, Monte S; Houser, Steven R; Tzima, Ellie

    2015-01-19

    Dilated cardiomyopathy is characterized by impaired contractility of cardiomyocytes, ventricular chamber dilatation, and systolic dysfunction. Although mutations in genes expressed in the cardiomyocyte are the best described causes of reduced contractility, the importance of endothelial-cardiomyocyte communication for proper cardiac function is increasingly appreciated. In the present study, we investigate the role of the endothelial adhesion molecule platelet endothelial cell adhesion molecule (PECAM-1) in the regulation of cardiac function. Using cell culture and animal models, we show that PECAM-1 expressed in endothelial cells (ECs) regulates cardiomyocyte contractility and cardiac function via the neuregulin-ErbB signaling pathway. Conscious echocardiography revealed left ventricular (LV) chamber dilation and systolic dysfunction in PECAM-1(-/-) mice in the absence of histological abnormalities or defects in cardiac capillary density. Despite deficits in global cardiac function, cardiomyocytes isolated from PECAM-1(-/-) hearts displayed normal baseline and isoproterenol-stimulated contractility. Mechanistically, absence of PECAM-1 resulted in elevated NO/ROS signaling and NRG-1 release from ECs, which resulted in augmented phosphorylation of its receptor ErbB2. Treatment of cardiomyocytes with conditioned media from PECAM-1(-/-) ECs resulted in enhanced ErbB2 activation, which was normalized by pre-treatment with an NRG-1 blocking antibody. To determine whether normalization of increased NRG-1 levels could correct cardiac function, PECAM-1(-/-) mice were treated with the NRG-1 blocking antibody. Echocardiography showed that treatment significantly improved cardiac function of PECAM-1(-/-) mice, as revealed by increased ejection fraction and fractional shortening. We identify a novel role for PECAM-1 in regulating cardiac function via a paracrine NRG1-ErbB pathway. These data highlight the importance of tightly regulated cellular communication for proper

  14. Regulation of Thrombin-Induced Lung Endothelial Cell Barrier Disruption by Protein Kinase C Delta

    PubMed Central

    Xie, Lishi; Chiang, Eddie T.; Kelly, Gabriel T.; Kanteti, Prasad; Singleton, Patrick A.; Camp, Sara M.; Zhou, Tingting; Dudek, Steven M.; Natarajan, Viswanathan; Wang, Ting; Black, Steven M.; Garcia, Joe G. N.; Jacobson, Jeffrey R.

    2016-01-01

    Protein Kinase C (PKC) plays a significant role in thrombin-induced loss of endothelial cell (EC) barrier integrity; however, the existence of more than 10 isozymes of PKC and tissue–specific isoform expression has limited our understanding of this important second messenger in vascular homeostasis. In this study, we show that PKCδ isoform promotes thrombin-induced loss of human pulmonary artery EC barrier integrity, findings substantiated by PKCδ inhibitory studies (rottlerin), dominant negative PKCδ construct and PKCδ silencing (siRNA). In addition, we identified PKCδ as a signaling mediator upstream of both thrombin-induced MLC phosphorylation and Rho GTPase activation affecting stress fiber formation, cell contraction and loss of EC barrier integrity. Our inhibitor-based studies indicate that thrombin-induced PKCδ activation exerts a positive feedback on Rho GTPase activation and contributes to Rac1 GTPase inhibition. Moreover, PKD (or PKCμ) and CPI-17, two known PKCδ targets, were found to be activated by PKCδ in EC and served as modulators of cytoskeleton rearrangement. These studies clarify the role of PKCδ in EC cytoskeleton regulation, and highlight PKCδ as a therapeutic target in inflammatory lung disorders, characterized by the loss of barrier integrity, such as acute lung injury and sepsis. PMID:27442243

  15. Rap-afadin axis in control of Rho signaling and endothelial barrier recovery

    PubMed Central

    Birukova, Anna A.; Tian, Xinyong; Tian, Yufeng; Higginbotham, Katherine; Birukov, Konstantin G.

    2013-01-01

    Activation of the Rho GTPase pathway determines endothelial cell (EC) hyperpermeability after injurious stimuli. To date, feedback mechanisms of Rho down-regulation critical for barrier restoration remain poorly understood. We tested a hypothesis that Rho down-regulation and barrier recovery of agonist-stimulated ECs is mediated by the Ras family GTPase Rap1. Thrombin-induced EC permeability driven by rapid activation of the Rho GTPase pathway was followed by Src kinase–dependent phosphorylation of the Rap1-specific guanine nucleotide exchange factor (GEF) C3G, activation of Rap1, and initiation of EC barrier recovery. Knockdown experiments showed that Rap1 activation was essential for down-regulation of Rho signaling and actin stress fiber dissolution. Rap1 activation also enhanced interaction between adherens junction (AJ) proteins VE-cadherin and p120-catenin and stimulated AJ reannealing mediated by the Rap1 effector afadin. This mechanism also included Rap1-dependent membrane translocation of the Rac1-specific GEF Tiam1 and activation of Rac1-dependent peripheral cytoskeletal dynamics, leading to resealing of intercellular gaps. These data demonstrate that activation of the Rap1-afadin axis is a physiological mechanism driving restoration of barrier integrity in agonist-stimulated EC monolayers via negative-feedback regulation of Rho signaling, stimulation of actin peripheral dynamics, and reestablishment of cell–cell adhesive complexes. PMID:23864716

  16. Junctional complex and focal adhesion rearrangement mediates pulmonary endothelial barrier enhancement by FTY720 S-phosphonate.

    PubMed

    Wang, Lichun; Bittman, Robert; Garcia, Joe G N; Dudek, Steven M

    2015-05-01

    Modulation of pulmonary vascular barrier function is an important clinical goal given the devastating effects of vascular leak in acute lung injury (ALI). We previously demonstrated that FTY720 S-phosphonate (Tys), an analog of sphingosine 1-phosphate (S1P) and FTY720, has more potent pulmonary barrier protective effects than these agents in vitro and in mouse models of ALI. Tys preserves expression of the barrier-promoting S1P1 receptor (S1PR1), whereas S1P and FTY720 induce its ubiquitination and degradation. Here we further characterize the novel barrier promoting effects of Tys in cultured human pulmonary endothelial cells (EC). In human lung EC, Tys significantly increased peripheral redistribution of adherens junction proteins VE-cadherin and β-catenin and tight junction protein ZO-1. Inhibition of VE-cadherin with blocking antibody significantly attenuated Tys-induced transendothelial resistance (TER) elevation, while ZO-1 siRNA partially inhibited this elevation. Tys significantly increased focal adhesion formation and phosphorylation of focal adhesion kinase (FAK). Pharmacologic inhibition of FAK significantly attenuated Tys-induced TER elevation. Tys significantly increased phosphorylation and peripheral redistribution of the actin-binding protein, cortactin, while cortactin siRNA partially attenuated Tys-induced TER elevation. Although Tys significantly increased phosphorylation of Akt and GSK3β, neither PI3 kinase nor GSK3β inhibition altered Tys-induced TER elevation. Tys significantly increased Rac1 activity, while inhibition of Rac1 activity significantly attenuated Tys-induced VE-cadherin redistribution and TER elevation. Junctional complex, focal adhesion rearrangement and Rac1 activation play critical roles in Tys-mediated barrier protection in pulmonary EC. These results provide mechanistic insights into the effects of this potential ALI therapy. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Lymph-Borne Chemokines and Other Low Molecular Weight Molecules Reach High Endothelial Venules via Specialized Conduits While a Functional Barrier Limits Access to the Lymphocyte Microenvironments in Lymph Node Cortex

    PubMed Central

    Gretz, J. Elizabeth; Norbury, Christopher C.; Anderson, Arthur O.; Proudfoot, Amanda E.I.; Shaw, Stephen

    2000-01-01

    Lymph-borne, soluble factors (e.g., chemokines and others) influence lymphocyte recirculation and endothelial phenotype at high endothelial venules (HEVs) in lymph node cortex. Yet the route lymph-borne soluble molecules travel from the subcapsular sinus to the HEVs is unclear. Therefore, we injected subcutaneously into mice and rats a wide variety of fluorophore-labeled, soluble molecules and examined their distribution in the draining lymph nodes. Rather than percolating throughout the draining lymph node, all molecules, including microbial lipopolysaccharide, were very visible in the subcapsular and medullary sinuses but were largely excluded from the cortical lymphocyte microenvironments. Exclusion prevailed even during the acute lymph node enlargement accompanying viral infection. However, low molecular mass (MW) molecules, including chemokines, did gain entry into the cortex, but in a very defined manner. Low MW, fluorophore-labeled molecules highlighted the subcapsular sinus, the reticular fibers, and the abluminal and luminal surfaces of the associated HEVs. These low MW molecules were in the fibers of the reticular network, a meshwork of collagen fibers ensheathed by fibroblastic reticular cells that connects the subcapsular sinus floor and the HEVs by intertwining with their basement membranes. Thus, low MW, lymph-borne molecules, including chemokines, traveled rapidly from the subcapsular sinus to the HEVs using the reticular network as a conduit. PMID:11085745

  18. β2 integrin-mediated crawling on endothelial ICAM-1 and ICAM-2 is a prerequisite for transcellular neutrophil diapedesis across the inflamed blood-brain barrier.

    PubMed

    Gorina, Roser; Lyck, Ruth; Vestweber, Dietmar; Engelhardt, Britta

    2014-01-01

    In acute neuroinflammatory states such as meningitis, neutrophils cross the blood-brain barrier (BBB) and contribute to pathological alterations of cerebral function. The mechanisms that govern neutrophil migration across the BBB are ill defined. Using live-cell imaging, we show that LPS-stimulated BBB endothelium supports neutrophil arrest, crawling, and diapedesis under physiological flow in vitro. Investigating the interactions of neutrophils from wild-type, CD11a(-/-), CD11b(-/-), and CD18(null) mice with wild-type, junctional adhesion molecule-A(-/-), ICAM-1(null), ICAM-2(-/-), or ICAM-1(null)/ICAM-2(-/-) primary mouse brain microvascular endothelial cells, we demonstrate that neutrophil arrest, polarization, and crawling required G-protein-coupled receptor-dependent activation of β2 integrins and binding to endothelial ICAM-1. LFA-1 was the prevailing ligand for endothelial ICAM-1 in mediating neutrophil shear resistant arrest, whereas Mac-1 was dominant over LFA-1 in mediating neutrophil polarization on the BBB in vitro. Neutrophil crawling was mediated by endothelial ICAM-1 and ICAM-2 and neutrophil LFA-1 and Mac-1. In the absence of crawling, few neutrophils maintained adhesive interactions with the BBB endothelium by remaining either stationary on endothelial junctions or displaying transient adhesive interactions characterized by a fast displacement on the endothelium along the direction of flow. Diapedesis of stationary neutrophils was unchanged by the lack of endothelial ICAM-1 and ICAM-2 and occurred exclusively via the paracellular pathway. Crawling neutrophils, although preferentially crossing the BBB through the endothelial junctions, could additionally breach the BBB via the transcellular route. Thus, β2 integrin-mediated neutrophil crawling on endothelial ICAM-1 and ICAM-2 is a prerequisite for transcellular neutrophil diapedesis across the inflamed BBB.

  19. Gold Nanoparticles Increase Endothelial Paracellular Permeability by Altering Components of Endothelial Tight Junctions, and Increase Blood-Brain Barrier Permeability in Mice.

    PubMed

    Li, Ching-Hao; Shyu, Ming-Kwang; Jhan, Cheng; Cheng, Yu-Wen; Tsai, Chi-Hao; Liu, Chen-Wei; Lee, Chen-Chen; Chen, Ruei-Ming; Kang, Jaw-Jou

    2015-11-01

    Gold nanoparticles (Au-NPs) are being increasingly used as constituents in cosmetics, biosensors, bioimaging, photothermal therapy, and targeted drug delivery. This elevated exposure to Au-NPs poses systemic risks in humans, particularly risks associated with the biodistribution of Au-NPs and their potent interaction with biological barriers. We treated human umbilical vein endothelial cells with Au-NPs and comprehensively examined the expression levels of tight junction (TJ) proteins such as occludin, claudin-5, junctional adhesion molecules, and zonula occludens-1 (ZO-1), as well as endothelial paracellular permeability and the intracellular signaling required for TJ organization. Moreover, we validated the effects of Au-NPs on the integrity of TJs in mouse brain microvascular endothelial cells in vitro and obtained direct evidence of their influence on blood-brain barrier (BBB) permeability in vivo. Treatment with Au-NPs caused a pronounced reduction of PKCζ-dependent threonine phosphorylation of occludin and ZO-1, which resulted in the instability of endothelial TJs and led to proteasome-mediated degradation of TJ components. This impairment in the assembly of TJs between endothelial cells increased the permeability of the transendothelial paracellular passage and the BBB. Au-NPs increased endothelial paracellular permeability in vitro and elevated BBB permeability in vivo. Future studies must investigate the direct and indirect toxicity caused by Au-NP-induced endothelial TJ opening and thereby address the double-edged-sword effect of Au-NPs. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Particulate matter air pollution disrupts endothelial cell barrier via calpain-mediated tight junction protein degradation

    PubMed Central

    2012-01-01

    Background Exposure to particulate matter (PM) is a significant risk factor for increased cardiopulmonary morbidity and mortality. The mechanism of PM-mediated pathophysiology remains unknown. However, PM is proinflammatory to the endothelium and increases vascular permeability in vitro and in vivo via ROS generation. Objectives We explored the role of tight junction proteins as targets for PM-induced loss of lung endothelial cell (EC) barrier integrity and enhanced cardiopulmonary dysfunction. Methods Changes in human lung EC monolayer permeability were assessed by Transendothelial Electrical Resistance (TER) in response to PM challenge (collected from Ft. McHenry Tunnel, Baltimore, MD, particle size >0.1 μm). Biochemical assessment of ROS generation and Ca2+ mobilization were also measured. Results PM exposure induced tight junction protein Zona occludens-1 (ZO-1) relocation from the cell periphery, which was accompanied by significant reductions in ZO-1 protein levels but not in adherens junction proteins (VE-cadherin and β-catenin). N-acetyl-cysteine (NAC, 5 mM) reduced PM-induced ROS generation in ECs, which further prevented TER decreases and atteneuated ZO-1 degradation. PM also mediated intracellular calcium mobilization via the transient receptor potential cation channel M2 (TRPM2), in a ROS-dependent manner with subsequent activation of the Ca2+-dependent protease calpain. PM-activated calpain is responsible for ZO-1 degradation and EC barrier disruption. Overexpression of ZO-1 attenuated PM-induced endothelial barrier disruption and vascular hyperpermeability in vivo and in vitro. Conclusions These results demonstrate that PM induces marked increases in vascular permeability via ROS-mediated calcium leakage via activated TRPM2, and via ZO-1 degradation by activated calpain. These findings support a novel mechanism for PM-induced lung damage and adverse cardiovascular outcomes. PMID:22931549

  1. Comparative evaluation of the impact on endothelial cells induced by different nanoparticle structures and functionalization

    PubMed Central

    Müller, Ines; Ernst, Peter; Schäfer, Miriam; Rosman, Christina; Schick, Isabel; Köhler, Oskar; Oehring, Hartmut; Breus, Vladimir V; Basché, Thomas; Sönnichsen, Carsten; Tremel, Wolfgang

    2015-01-01

    Summary In the research field of nanoparticles, many studies demonstrated a high impact of the shape, size and surface charge, which is determined by the functionalization, of nanoparticles on cell viability and internalization into cells. This work focused on the comparison of three different nanoparticle types to give a better insight into general rules determining the biocompatibility of gold, Janus and semiconductor (quantum dot) nanoparticles. Endothelial cells were subject of this study, since blood is the first barrier after intravenous nanoparticle application. In particular, stronger effects on the viability of endothelial cells were found for nanoparticles with an elongated shape in comparison to spherical ones. Furthermore, a positively charged nanoparticle surface (NH2, CyA) leads to the strongest reduction in cell viability, whereas neutral and negatively charged nanoparticles are highly biocompatible to endothelial cells. These findings are attributed to a rapid internalization of the NH2-functionalized nanoparticles in combination with the damage of intracellular membranes. Interestingly, the endocytotic pathway seems to be a size-dependent process whereas nanoparticles with a size of 20 nm are internalized by caveolae-mediated endocytosis and nanoparticles with a size of 40 nm are taken up by clathrin-mediated internalization and macropinocytosis. Our results can be summarized to formulate five general rules, which are further specified in the text and which determine the biocompatibility of nanoparticles on endothelial cells. Our findings will help to design new nanoparticles with optimized properties concerning biocompatibility and uptake behavior with respect to the respective intended application. PMID:25821668

  2. Hepatocyte growth factor triggers distinct mechanisms of Asef and Tiam1 activation to induce endothelial barrier enhancement

    PubMed Central

    Higginbotham, Katherine; Tian, Yufeng; Gawlak, Grzegorz; Moldobaeva, Nurgul; Shah, Alok; Birukova, Anna A.

    2014-01-01

    Previous reports described important role of hepatocyte growth factor (HGF) in mitigation of pulmonary endothelial barrier dysfunction and cell injury induced by pathologic agonists and mechanical forces. HGF protective effects have been associated with Rac-GTPase signaling pathway activated by Rac-specific guanine nucleotide exchange factor Tiam1 and leading to enhancement of intercellular adherens junctions. This study tested involvement of a novel Rac-specific activator, Asef, in endothelial barrier enhancement by HGF and investigated a mechanism of HGF-induced Asef activation. Si-RNA-based knockdown of Tiam1 and Asef had an additive effect on attenuation of HGF-induced Rac activation and endothelial cell (EC) barrier enhancement. Tiam1 and Asef activation was abolished by pharmacologic inhibitors of HGF receptor and PI3-kinase. In contrast to Tiam1, Asef interacted with APC and associated with microtubule fraction upon HGF stimulation. EC treatment by low dose nocodazole to inhibit peripheral microtubule dynamics partially attenuated HGF-induced Asef peripheral translocation, but had negligible effect on Tiam1 translocation. These effects were associated with attenuation of HGF-induced barrier enhancement in EC pretreated with low ND dose and activation of Rac and its cytoskeletal effectors PAK1 and cortactin. These data demonstrate, that in addition to microtubule-independent Tiam1 activation, HGF engages additional microtubule- and APC-dependent pathway of Asef activation. These mechanisms may complement each other to provide the fine tuning of Rac signaling and endothelial barrier enhancement in response to various agonists. PMID:25101856

  3. Permanent isolation surface barrier: Functional performance

    SciTech Connect

    Wing, N.R.

    1993-10-01

    This document presents the functional performance parameters for permanent isolation surface barriers. Permanent isolation surface barriers have been proposed for use at the Hanford Site (and elsewhere) to isolate and dispose of certain types of waste in place. Much of the waste that would be disposed of using in-place isolation techniques is located in subsurface structures, such as solid waste burial grounds, tanks, vaults, and cribs. Unless protected in some way, the wastes could be transported to the accessible environment via transport pathways, such as water infiltration, biointrusion, wind and water erosion, human interference, and/or gaseous release.

  4. Resveratrol attenuates lipopolysaccharide-induced dysfunction of blood-brain barrier in endothelial cells via AMPK activation

    PubMed Central

    2016-01-01

    Resveratrol, a phytoalexin, is reported to activate AMP-activated protein kinase (AMPK) in vascular cells. The blood-brain barrier (BBB), formed by specialized brain endothelial cells that are interconnected by tight junctions, strictly regulates paracellular permeability to maintain an optimal extracellular environment for brain homeostasis. The aim of this study was to elucidate the effects of resveratrol and the role of AMPK in BBB dysfunction induced by lipopolysaccharide (LPS). Exposure of human brain microvascular endothelial cells (HBMECs) to LPS (1 µg/ml) for 4 to 24 hours week dramatically increased the permeability of the BBB in parallel with lowered expression levels of occluding and claudin-5, which are essential to maintain tight junctions in HBMECs. In addition, LPS significantly increased the reactive oxygen species (ROS) productions. All effects induced by LPS in HBVMCs were reversed by adenoviral overexpression of superoxide dismutase, inhibition of NAD(P) H oxidase by apocynin or gain-function of AMPK by adenoviral overexpression of constitutively active mutant (AMPK-CA) or by resveratrol. Finally, upregulation of AMPK by either AMPK-CA or resveratrol abolished the levels of LPS-enhanced NAD(P)H oxidase subunits protein expressions. We conclude that AMPK activation by resveratrol improves the integrity of the BBB disrupted by LPS through suppressing the induction of NAD(P)H oxidase-derived ROS in HBMECs. PMID:27382348

  5. Epidermal Growth Factor and Intestinal Barrier Function

    PubMed Central

    Liu, Hu; Yang, Shufen; Li, Zuohua; Zhong, Jinfeng

    2016-01-01

    Epidermal growth factor (EGF) is a 53-amino acid peptide that plays an important role in regulating cell growth, survival, migration, apoptosis, proliferation, and differentiation. In addition, EGF has been established to be an effective intestinal regulator helping to protect intestinal barrier integrity, which was essential for the absorption of nutrients and health in humans and animals. Several researches have demonstrated that EGF via binding to the EGF receptor and subsequent activation of Ras/MAPK, PI3K/AKT, PLC-γ/PKC, and STATS signal pathways regulates intestinal barrier function. In this review, the relationship between epidermal growth factor and intestinal development and intestinal barrier is described, to provide a better understanding of the effects of EGF on intestine development and health. PMID:27524860

  6. Plant-derived triterpene celastrol ameliorates oxygen glucose deprivation-induced disruption of endothelial barrier assembly via inducing tight junction proteins.

    PubMed

    Luo, Dan; Zhao, Jia; Rong, Jianhui

    2016-12-01

    The integrity and functions of blood-brain barrier (BBB) are regulated by the expression and organization of tight junction proteins. The present study was designed to explore whether plant-derived triterpenoid celastrol could regulate tight junction integrity in murine brain endothelial bEnd3 cells. We disrupted the tight junctions between endothelial bEnd3 cells by oxygen glucose deprivation (OGD). We investigated the effects of celastrol on the permeability of endothelial monolayers by measuring transepithelial electrical resistance (TEER). To clarify the tight junction composition, we analyzed the expression of tight junction proteins by RT-PCR and Western blotting techniques. We found that celastrol recovered OGD-induced TEER loss in a concentration-dependent manner. Celastrol induced occludin, claudin-5 and zonula occludens-1 (ZO-1) in endothelial cells. As a result, celastrol effectively maintained tight junction integrity and inhibited macrophage migration through endothelial monolayers against OGD challenge. Further mechanistic studies revealed that celastrol induced the expression of occludin and ZO-1) via activating MAPKs and PI3K/Akt/mTOR pathway. We also observed that celastrol regulated claudin-5 expression through different mechanisms. The present study demonstrated that celastrol effectively protected tight junction integrity against OGD-induced damage. Thus, celastrol could be a drug candidate for the treatment of BBB dysfunction in various diseases. Copyright © 2016 Elsevier GmbH. All rights reserved.

  7. Proliferation status defines functional properties of endothelial cells.

    PubMed

    Lipps, Christoph; Badar, Muhammad; Butueva, Milada; Dubich, Tatyana; Singh, Vivek Vikram; Rau, Sophie; Weber, Axel; Kracht, Michael; Köster, Mario; May, Tobias; Schulz, Thomas F; Hauser, Hansjörg; Wirth, Dagmar

    2017-04-01

    Homeostasis of solid tissue is characterized by a low proliferative activity of differentiated cells while special conditions like tissue damage induce regeneration and proliferation. For some cell types it has been shown that various tissue-specific functions are missing in the proliferating state, raising the possibility that their proliferation is not compatible with a fully differentiated state. While endothelial cells are important players in regenerating tissue as well as in the vascularization of tumors, the impact of proliferation on their features remains elusive. To examine cell features in dependence of proliferation, we established human endothelial cell lines in which proliferation is tightly controlled by a doxycycline-dependent, synthetic regulatory unit. We observed that uptake of macromolecules and establishment of cell-cell contacts was more pronounced in the growth-arrested state. Tube-like structures were formed in vitro in both proliferating and non-proliferating conditions. However, functional vessel formation upon transplantation into immune-compromised mice was restricted to the proliferative state. Kaposi's sarcoma-associated herpes virus (KSHV) infection resulted in reduced expression of endothelial markers. Upon transplantation of infected cells, drastic differences were observed: proliferation arrested cells acquired a high migratory activity while the proliferating counterparts established a tumor-like phenotype, similar to Kaposi Sarcoma lesions. The study gives evidence that proliferation governs endothelial functions. This suggests that several endothelial functions are differentially expressed during angiogenesis. Moreover, since proliferation defines the functional properties of cells upon infection with KSHV, this process crucially affects the fate of virus-infected cells.

  8. Improvement of endothelial function following initiation of testosterone replacement therapy

    PubMed Central

    Tucky, Barbara; Polackwich, Allan S.

    2016-01-01

    Background Isolated recent studies have suggested an increased risk of heart attack as early as 3 months following testosterone replacement therapy (TRT). Such a rapid risk increase would likely require rapid deterioration of arterial endothelial function. Our goal was to assess arterial endothelial function in hypogonadal men prior to and at least 3 months after initiation of TRT. Methods Adult men were consented if they had symptoms of hypogonadism, a total testosterone <350 ng/dL, and planned to begin TRT. Endothelial function was non-invasively assessed using the EndoPAT-2000 machine. We measured the augmentation index (AI) (normal <3%), a measure of arterial stiffness and reactive hyperemia index (RHI), a measure of endothelial vasodilation (normal >1.69). Prior studies suggest that a 10% level of day-to-day test variability is expected. Endothelial function was reassessed at the next clinic visit, between 3 and 6 months if the patients were compliant with therapy. Changes in continuous variables were assessed with the paired t test. Results Twenty-three patients were consented with a mean age of 52.7 years (range, 34–68 years) and starting testosterone 196.9 ng/dL (range, 35–339 ng/dL). There was a history of diabetes in four, hypertension in ten and coronary artery disease in five. Mean RHI was 1.67±0.37 (70% were abnormal) and mean AI was 2.57%±14.0% (39% were abnormal). There were no cardiac events. At follow-up 20 patients were compliant with therapy and retested. Mean testosterone increased from 203 to 511 (P<0.0001). Mean RHI improved from 1.70 to 2.14 (P=0.01). Mean AI improved from 2.9% to −1.75% (P=0.01). In four men RHI worsened but in each case less than the 10% error of the test. No man had worsened AI. Conclusions Men with symptomatic hypogonadism often have abnormal arterial endothelial function. Following TRT, endothelial function either remains unchanged or improves. PMID:28078212

  9. Cerebral hemodynamics and endothelial function in patients with Fabry disease.

    PubMed

    Segura, Tomás; Ayo-Martín, Oscar; Gómez-Fernandez, Isabel; Andrés, Carolina; Barba, Miguel A; Vivancos, José

    2013-11-11

    Cerebral vasculopathy have been described in Fabry disease, in which altered cerebral blood flow, vascular remodelling or impairment of endothelial function could be involved. Our study aims to evaluate these three possibilities in a group of Fabry patients, and compare it to healthy controls. Cerebral hemodynamics, vascular remodelling and systemic endothelial function were investigated in 10 Fabry patients and compared to data from 17 healthy controls. Transcranial Doppler was used to study blood flow velocity of intracranial arteries and cerebral vasomotor reactivity. For the study of vascular remodelling and endothelial function, intima-media thickness of common carotid arteries, flow-mediated dilation in brachial artery and serum levels of soluble VCAM-1, TNF-α, high-sensitive CRP and IL-6 were measured. Differences between groups were evaluated using appropriate tests. No relevant differences were observed in cerebral hemodynamic parameters, intima-media thickness or flow-mediated dilation. There was a trend for low serum levels of IL-6 and high serum levels of TNF-α and high-sensitive CRP in Fabry patients; plasma concentrations of soluble VCAM-1 were significantly higher in Fabry disease patients than in healthy volunteers (p = 0.02). In our sample, we did not find relevant alterations of cerebral hemodynamics in Fabry disease patients. Increased levels of plasmatic endothelial biomarkers seem to be the most important feature indicative of possible vascular dysfunction in Fabry disease patients.

  10. Cerebral hemodynamics and endothelial function in patients with Fabry disease

    PubMed Central

    2013-01-01

    Background Cerebral vasculopathy have been described in Fabry disease, in which altered cerebral blood flow, vascular remodelling or impairment of endothelial function could be involved. Our study aims to evaluate these three possibilities in a group of Fabry patients, and compare it to healthy controls. Methods Cerebral hemodynamics, vascular remodelling and systemic endothelial function were investigated in 10 Fabry patients and compared to data from 17 healthy controls. Transcranial Doppler was used to study blood flow velocity of intracranial arteries and cerebral vasomotor reactivity. For the study of vascular remodelling and endothelial function, intima-media thickness of common carotid arteries, flow-mediated dilation in brachial artery and serum levels of soluble VCAM-1, TNF-α, high-sensitive CRP and IL-6 were measured. Differences between groups were evaluated using appropriate tests. Results No relevant differences were observed in cerebral hemodynamic parameters, intima-media thickness or flow-mediated dilation. There was a trend for low serum levels of IL-6 and high serum levels of TNF-α and high-sensitive CRP in Fabry patients; plasma concentrations of soluble VCAM-1 were significantly higher in Fabry disease patients than in healthy volunteers (p = 0.02). Conclusions In our sample, we did not find relevant alterations of cerebral hemodynamics in Fabry disease patients. Increased levels of plasmatic endothelial biomarkers seem to be the most important feature indicative of possible vascular dysfunction in Fabry disease patients. PMID:24207059

  11. Arginase inhibition restores endothelial function in diet-induced obesity.

    PubMed

    Chung, Ji Hyung; Moon, Jiyoung; Lee, Youn Sue; Chung, Hye-Kyung; Lee, Seung-Min; Shin, Min-Jeong

    2014-08-22

    Arginase may play a major role in the regulation of vascular function in various cardiovascular disorders by impairing nitric oxide (NO) production. In the current study, we investigated whether supplementation of the arginase inhibitor N(ω)-hydroxy-nor-l-arginine (nor-NOHA) could restore endothelial function in an animal model of diet-induced obesity. Arginase 1 expression was significantly lower in the aorta of C57BL/6J mice fed a high-fat diet (HFD) supplemented with nor-NOHA (40mgkg(-1)/day) than in mice fed HFD without nor-NOHA. Arginase inhibition led to considerable increases in eNOS expression and NO levels and significant decreases in the levels of circulating ICAM-1. These findings were further confirmed by the results of siRNA-mediated knockdown of Arg in human umbilical vein endothelial cells. In conclusion, arginase inhibition can help restore dysregulated endothelial function by increasing the eNOS-dependent NO production in the endothelium, indicating that arginase could be a therapeutic target for correcting obesity-induced vascular endothelial dysfunction.

  12. Cancer-secreted miR-105 destroys vascular endothelial barriers to promote metastasis

    PubMed Central

    Zhou, Weiying; Fong, Miranda Y.; Min, Yongfen; Somlo, George; Liu, Liang; Palomares, Melanie R.; Yu, Yang; Chow, Amy; O’Connor, Sean Timothy Francis; Chin, Andrew R.; Yen, Yun; Wang, Yafan; Marcusson, Eric G.; Chu, Peiguo; Wu, Jun; Wu, Xiwei; Li, Arthur Xuejun; Li, Zhuo; Gao, Hanlin; Ren, Xiubao; Boldin, Mark P.; Lin, Pengnian Charles; Wang, Shizhen Emily

    2014-01-01

    SUMMARY Cancer-secreted miRNAs are emerging mediators of cancer–host crosstalk. Here we show that miR-105, which is characteristically expressed and secreted by metastatic breast cancer cells, is a potent regulator of migration through targeting the tight junction protein ZO-1. In endothelial monolayers, exosome-mediated transfer of cancer-secreted miR-105 efficiently destroys tight junctions and the integrity of these natural barriers against metastasis. Overexpression of miR-105 in non-metastatic cancer cells induces metastasis and vascular permeability in distant organs, whereas inhibition of miR-105 in highly metastatic tumors alleviates these effects. MiR-105 can be detected in the circulation at the pre-metastatic stage, and its levels in the blood and tumor are associated with ZO-1 expression and metastatic progression in early-stage breast cancer. PMID:24735924

  13. Physiologically assessed hot flashes and endothelial function among midlife women.

    PubMed

    Thurston, Rebecca C; Chang, Yuefang; Barinas-Mitchell, Emma; Jennings, J Richard; von Känel, Roland; Landsittel, Doug P; Matthews, Karen A

    2017-08-01

    Hot flashes are experienced by most midlife women. Emerging data indicate that they may be associated with endothelial dysfunction. No studies have tested whether hot flashes are associated with endothelial function using physiologic measures of hot flashes. We tested whether physiologically assessed hot flashes were associated with poorer endothelial function. We also considered whether age modified associations. Two hundred seventy-two nonsmoking women reporting either daily hot flashes or no hot flashes, aged 40 to 60 years, and free of clinical cardiovascular disease, underwent ambulatory physiologic hot flash and diary hot flash monitoring; a blood draw; and ultrasound measurement of brachial artery flow-mediated dilation to assess endothelial function. Associations between hot flashes and flow-mediated dilation were tested in linear regression models controlling for lumen diameter, demographics, cardiovascular disease risk factors, and estradiol. In multivariable models incorporating cardiovascular disease risk factors, significant interactions by age (P < 0.05) indicated that among the younger tertile of women in the sample (age 40-53 years), the presence of hot flashes (beta [standard error] = -2.07 [0.79], P = 0.01), and more frequent physiologic hot flashes (for each hot flash: beta [standard error] = -0.10 [0.05], P = 0.03, multivariable) were associated with lower flow-mediated dilation. Associations were not accounted for by estradiol. Associations were not observed among the older women (age 54-60 years) or for self-reported hot flash frequency, severity, or bother. Among the younger women, hot flashes explained more variance in flow-mediated dilation than standard cardiovascular disease risk factors or estradiol. Among younger midlife women, frequent hot flashes were associated with poorer endothelial function and may provide information about women's vascular status beyond cardiovascular disease risk factors and estradiol.

  14. [Endothelial cell adhesion molecules].

    PubMed

    Ivanov, A N; Norkin, I A; Puchin'ian, D M; Shirokov, V Iu; Zhdanova, O Iu

    2014-01-01

    The review presents current data concerning the functional role of endothelial cell adhesion molecules belonging to different structural families: integrins, selectins, cadherins, and the immunoglobulin super-family. In this manuscript the regulatory mechanisms and factors of adhesion molecules expression and distribution on the surface of endothelial cells are discussed. The data presented reveal the importance of adhesion molecules in the regulation of structural and functional state of endothelial cells in normal conditions and in pathology. Particular attention is paid to the importance of these molecules in the processes of physiological and pathological angiogenesis, regulation of permeability of the endothelial barrier and cell transmigration.

  15. Bile duct epithelial tight junctions and barrier function.

    PubMed

    Rao, R K; Samak, G

    2013-10-01

    Bile ducts play a crucial role in the formation and secretion of bile as well as excretion of circulating xenobiotic substances. In addition to its secretory and excretory functions, bile duct epithelium plays an important role in the formation of a barrier to the diffusion of toxic substances from bile into the hepatic interstitial tissue. Disruption of barrier function and toxic injury to liver cells appear to be involved in the pathogenesis of a variety of liver diseases such as primary sclerosing cholangitis, primary biliary cirrhosis and cholangiocarcinoma. Although the investigations into understanding the structure and regulation of tight junctions in gut, renal and endothelial tissues have expanded rapidly, very little is known about the structure and regulation of tight junctions in the bile duct epithelium. In this article we summarize the current understanding of physiology and pathophysiology of bile duct epithelium, the structure and regulation of tight junctions in canaliculi and bile duct epithelia and different mechanisms involved in the regulation of disruption and protection of bile duct epithelial tight junctions. This article will make a case for the need of future investigations toward our understanding of molecular organization and regulation of canalicular and bile duct epithelial tight junctions.

  16. Bile duct epithelial tight junctions and barrier function

    PubMed Central

    Rao, R.K.; Samak, G.

    2013-01-01

    Bile ducts play a crucial role in the formation and secretion of bile as well as excretion of circulating xenobiotic substances. In addition to its secretory and excretory functions, bile duct epithelium plays an important role in the formation of a barrier to the diffusion of toxic substances from bile into the hepatic interstitial tissue. Disruption of barrier function and toxic injury to liver cells appear to be involved in the pathogenesis of a variety of liver diseases such as primary sclerosing cholangitis, primary biliary cirrhosis and cholangiocarcinoma. Although the investigations into understanding the structure and regulation of tight junctions in gut, renal and endothelial tissues have expanded rapidly, very little is known about the structure and regulation of tight junctions in the bile duct epithelium. In this article we summarize the current understanding of physiology and pathophysiology of bile duct epithelium, the structure and regulation of tight junctions in canaliculi and bile duct epithelia and different mechanisms involved in the regulation of disruption and protection of bile duct epithelial tight junctions. This article will make a case for the need of future investigations toward our understanding of molecular organization and regulation of canalicular and bile duct epithelial tight junctions. PMID:24665411

  17. Importance of Tight Junctions in Relation to Skin Barrier Function.

    PubMed

    Brandner, Johanna M

    2016-01-01

    Tight junctions (TJs) are complex cell-cell junctions that form a barrier in the stratum granulosum of mammalian skin. Besides forming a barrier themselves, TJs influence other skin barriers, e.g. the stratum corneum barrier, and are influenced by other skin barriers, e.g. by the chemical, the microbiome, or the immunological barrier and likely by the basement membrane. This review summarizes the dynamic interaction of the TJ barrier with other barriers in the skin and the central role of TJs in skin barrier function. © 2016 S. Karger AG, Basel.

  18. Examining the Role of Sphingosine Kinase-2 in the Regulation of Endothelial Cell Barrier Integrity.

    PubMed

    Dimasi, David P; Pitson, Stuart M; Bonder, Claudine S

    2016-04-01

    A key mediator of vascular EC barrier integrity, S1P, is derived from phosphorylation of sphingosine by the SK-1 and SK-2. While previous work indicates that SK-1 can regulate EC barrier integrity, whether SK-2 has a similar role remains to be determined. A cell impedance assay was used to assess human umbilical vein EC and bone marrow EC barrier integrity in vitro, with application of the SK inhibitors ABC294640, PF543, SKi, and MP-A08. In vivo studies were conducted using intravital microscopy to assess EC barrier integrity in SK-1 (Sphk1(-/-)) and SK-2 (Sphk2(-/-)) knock-out mice. Only ABC294640 and MP-A08, which can both inhibit SK-2, caused a decrease in EC barrier integrity in vitro in both cell types. Intravital microscopy revealed that Sphk1(-/-) mice had reduced EC barrier integrity compared to WT mice, whereas no change was evident in Sphk2(-/-) mice. Our data suggest that in vitro inhibition of SK-2, can compromise the integrity of the EC monolayer, while SK-1 exerts a more dominant control in vivo. These data may have clinical implications and could aid in the development of new treatments for disorders of vascular barrier function. © 2016 John Wiley & Sons Ltd.

  19. MicroRNA-107 prevents amyloid-beta induced blood-brain barrier disruption and endothelial cell dysfunction by targeting Endophilin-1.

    PubMed

    Liu, Wenjing; Cai, Heng; Lin, Meiqing; Zhu, Lu; Gao, Lili; Zhong, Renjia; Bi, Siwei; Xue, Yixue; Shang, Xiuli

    2016-05-01

    The disruption of blood-brain barrier (BBB) and endothelial cell dysfunction, associated with the cerebrovascular deposition of the amyloid-beta (Abeta) protein, have been characterized as the key pathological characteristics in Alzheimer's disease (AD). In various biologic processes of AD, researchers have proven that mircroRNAs (miRNAs) play critical roles. However, the role and function of miRNAs in the disruption of BBB of AD still remain unclear. Here, we found that mircroRNA-107 (miR-107) is endogenously expressed in human brain microvascular endothelial cells (ECs) of BBB model, while it is significantly down-regulated in ECs pre-incubated with Abeta. Abeta significantly impairs the integrity, increases the permeability of BBB, inhibits the viability of endothelial cells (ECs), and meanwhile down-regulates the expression of tight junction proteins ZO-1, Occludin and Claudin-5. Overexpression of miR-107 largely abrogated Abeta-induced disruption of BBB and endothelial cell dysfunction. Furthermore, overexpression of miR-107 also down-regulates endophilin-1, which is involved in the regulation of BBB permeability and the expression of ZO-1, Occludin, and Claudin-5. Both bioinformatics and luciferase reporter assays demonstrated that Endophilin-1 was a direct and functional downstream target of miR-107. In conclusion, our results indicate that overexpression of miR-107 is able to prevent Abeta-induced blood-brain barrier disruption and endothelial cell dysfunction by targeting endophilin-1. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Endothelial function markers in parkinsonian patients with hyperhomocysteinemia.

    PubMed

    Bostantjopoulou, Sevasti; Katsarou, Zoe; Frangia, Theodora; Hatzizisi, Olga; Papazisis, Kostas; Kyriazis, George; Kiosseoglou, Gregory; Kazis, Aristidis

    2005-08-01

    Hyperhomocysteinemia is considered a risk factor for vascular disease causing endothelial damage and consequently atherogenesis. The purpose of this study was to investigate the effect of elevated homocysteine on certain biochemical markers of endothelial function in patients with idiopathic Parkinson's disease (PD). Blood homocysteine levels were assessed in 57 PD patients and 40 matched normal controls. Investigation of the C677T 5,10 methylenetetrahydrofolate reductase (MTHFR) genotype was also performed in 43 PD patients. The following markers of endothelial function were assessed: superoxide dismutase (SOD), nitric oxide (NO), sICAM-1 and sE-selectin. Homocysteine levels were found mildly elevated in PD patients particularly in those treated with L-Dopa. MTHFR genotype did not influence significantly this finding. SOD activity was found reduced but it was not correlated to homocysteine levels. All other parameters measured were normal and were not related to hyperhomocysteinemia. Our findings indicate that mild hyperhomocysteinemia in PD patients was not associated with endothelial dysfunction.

  1. Endothelial MAPKs Direct ICAM-1 Signaling to Divergent Inflammatory Functions

    PubMed Central

    Dragoni, Silvia; Hudson, Natalie; Kenny, Bridget-Ann; Burgoyne, Thomas; McKenzie, Jenny A.; Gill, Yadvinder; Blaber, Robert; Futter, Clare E.; Adamson, Peter; Greenwood, John

    2017-01-01

    Lymphocyte transendothelial migration (TEM) is critically dependent on intraendothelial signaling triggered by adhesion to ICAM-1. Here we show that endothelial MAPKs ERK, p38, and JNK mediate diapedesis-related and diapedesis-unrelated functions of ICAM-1 in cerebral and dermal microvascular endothelial cells (MVECs). All three MAPKs were activated by ICAM-1 engagement, either through lymphocyte adhesion or Ab-mediated clustering. MAPKs were involved in ICAM-1–dependent expression of TNF-α in cerebral and dermal MVECs, and CXCL8, CCL3, CCL4, VCAM-1, and cyclooxygenase 2 (COX-2) in cerebral MVECs. Endothelial JNK and to a much lesser degree p38 were the principal MAPKs involved in facilitating diapedesis of CD4+ lymphocytes across both types of MVECs, whereas ERK was additionally required for TEM across dermal MVECs. JNK activity was critical for ICAM-1–induced F-actin rearrangements. Furthermore, activation of endothelial ICAM-1/JNK led to phosphorylation of paxillin, its association with VE-cadherin, and internalization of the latter. Importantly ICAM-1–induced phosphorylation of paxillin was required for lymphocyte TEM and converged functionally with VE-cadherin phosphorylation. Taken together we conclude that during lymphocyte TEM, ICAM-1 signaling diverges into pathways regulating lymphocyte diapedesis, and other pathways modulating gene expression thereby contributing to the long-term inflammatory response of the endothelium. PMID:28373581

  2. Endothelial function, folate pharmacogenomics, and neurocognition in psychotic disorders.

    PubMed

    Grove, Tyler; Taylor, Stephan; Dalack, Gregory; Ellingrod, Vicki

    2015-05-01

    Cardiovascular disease (CVD) is a well-described complication of schizophrenia, however, mechanisms connecting CVD with other facets of psychotic disorders, such as neurocognition, are not understood. The current study examined folate metabolism as a potential mechanism of CVD and neurocognitive deficits by: 1) using endothelial dysfunction as a biomarker of CVD, and 2) comparing enzymes associated with neurocognition, CVD, and critical to folate metabolism, methylenetetrahydrofolate reductase (MTHFR) and catechol-o-methyl transferase (COMT). Endothelial function was assessed in 147 participants with schizophrenia, schizoaffective disorder, and psychotic disorder not otherwise specified grouped by MTHFR and COMT allele status. Regression models were used to compare neurocognitive performance based on the Brief Assessment of Cognition in Schizophrenia (BACS). Overall, endothelial function predicted BACS composite z-scores after controlling for age, race, level of education, serum folate levels, and MTHFR/COMT risk allele status. Participants with at least one or more MTHFR and/or COMT risk alleles had lower BACS Composite and BACS Symbol Coding adjusted mean z-scores than those with both MTHFR CC and COMT Met/Met genotypes. Thus, endothelial dysfunction may contribute to the neurocognitive deficits seen in psychotic disorders. CVD interventions may not only reduce CVD-related morbidity, but also lessen progressive neurocognitive deficits reported in psychotic disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Simultaneous Non-Invasive Assessment of Systemic and Coronary Endothelial Function Iantorno et al: Cardiac MRI and Endothelial Function

    PubMed Central

    Schär, Michael; Krishnaswamy, Rupa; Soleimanifard, Sahar; Steinberg, Angela; Stuber, Matthias; Gerstenblith, Gary; Weiss, Robert G.

    2016-01-01

    Background Normal endothelial function is a measure of vascular health and dysfunction a predictor of coronary events. Nitric Oxide (NO)-mediated coronary artery endothelial function (CEF), as assessed by vasomotor reactivity during isometric handgrip exercise (IHE), was recently quantified noninvasively with MRI. Because the internal mammary artery (IMA) is often visualized during coronary MRI we propose the strategy of simultaneously assessing systemic and coronary endothelial function noninvasively by MRI during IHE. Methods and Results Changes in cross-sectional area (CSA) and blood flow (BF) in the right coronary artery (RCA) and the IMA in 25 CAD patients and 26 healthy subjects during IHE were assessed using 3T MRI. In 8 healthy subjects a NO synthase inhibitor was infused to evaluate the role of NO in the IMA-IHE response. Inter-observer IMA-IHE reproducibility was good for CSA (R=0.91) and BF (R=0.91). In healthy subjects, CSA and BF of the IMA increased during IHE and these responses were significantly attenuated by L-NMMA (p<0.01 vs. placebo). In CAD patients, the RCA did not dilate with IHE and dilation of the IMA was less than that of the healthy subjects (p=0.01). The BF responses of both the RCA and IMA to IHE were also significantly reduced in CAD patients. Conclusions MRI-detected IMA responses to IHE primarily reflect NO-dependent endothelial function, are reproducible and reduced in CAD patients. Endothelial function in both coronary and systemic (IMA) arteries can now be measured noninvasively with the same imaging technique and promises novel insights into systemic and local factors affecting vascular health. PMID:26919997

  4. Endothelial function in postmenopausal women with nighttime systolic hypertension

    PubMed Central

    Routledge, Faye S.; Hinderliter, Alan L.; McFetridge-Durdle, Judith; Blumenthal, James A.; Paine, Nicola J.; Sherwood, Andrew

    2014-01-01

    Objective Hypertension becomes more prevalent in women during their postmenopausal years. Nighttime systolic blood pressure (SBP) is especially predictive of adverse cardiac events and the relationship between rising nighttime SBP and cardiovascular risk increases more rapidly in women compared to men. The reasons for the prognostic significance of nighttime SBP are not completely known, but may involve vascular endothelial dysfunction. The purpose of this study was to examine the relationship of nighttime SBP and endothelial function, assessed by brachial artery flow-mediated dilation (FMD) and to determine whether postmenopausal women with nighttime hypertension (SBP≥120 mm Hg) evidenced greater endothelial dysfunction compared to women with normal nighttime SBP. Methods One-hundred postmenopausal women (mean age: 65.8 ± 7.5 years, body mass index: 28.3 ± 4.7 kg/m2, hypertension: 47%, coronary artery disease: 51%, mean clinic BP 137 ± 17/67 ± 11 mm Hg, 34 with nighttime hypertension) underwent 24-hour ambulatory BP monitoring, actigraphy, and brachial artery FMD assessments. Results Multivariate regression models showed that higher nighttime SBP and larger baseline artery diameter were inversely related to FMD. Nighttime SBP and baseline artery diameter accounted for 23% of the variance in FMD. After adjusting for baseline artery diameter, women with nighttime hypertension had lower FMD than women with normal nighttime SBP (2.95%±0.65 vs 5.52%±0.46, p = .002). Conclusions In postmenopausal women, nighttime hypertension was associated with reduced endothelial function. Research examining the therapeutic benefits of treating nighttime hypertension on endothelial function and future cardiovascular risk in postmenopausal women is warranted. PMID:25563797

  5. Endothelial β-Catenin Signaling Is Required for Maintaining Adult Blood-Brain Barrier Integrity and Central Nervous System Homeostasis.

    PubMed

    Tran, Khiem A; Zhang, Xianming; Predescu, Dan; Huang, Xiaojia; Machado, Roberto F; Göthert, Joachim R; Malik, Asrar B; Valyi-Nagy, Tibor; Zhao, You-Yang

    2016-01-12

    The blood-brain barrier (BBB) formed by brain endothelial cells interconnected by tight junctions is essential for the homeostasis of the central nervous system. Although studies have shown the importance of various signaling molecules in BBB formation during development, little is known about the molecular basis regulating the integrity of the adult BBB. Using a mouse model with tamoxifen-inducible endothelial cell-restricted disruption of ctnnb1 (iCKO), we show here that endothelial β-catenin signaling is essential for maintaining BBB integrity and central nervous system homeostasis in adult mice. The iCKO mice developed severe seizures accompanied by neuronal injury, multiple brain petechial hemorrhages, and central nervous system inflammation, and all had postictal death. Disruption of endothelial β-catenin induced BBB breakdown and downregulation of the specific tight junction proteins claudin-1 and -3 in adult brain endothelial cells. The clinical relevance of the data is indicated by the observation of decreased expression of claudin-1 and nuclear β-catenin in brain endothelial cells of hemorrhagic lesions of hemorrhagic stroke patients. These results demonstrate the prerequisite role of endothelial β-catenin in maintaining the integrity of adult BBB. The results suggest that BBB dysfunction secondary to defective β-catenin transcription activity is a key pathogenic factor in hemorrhagic stroke, seizure activity, and central nervous system inflammation. © 2015 American Heart Association, Inc.

  6. Epidermal vascular endothelial growth factor production is required for permeability barrier homeostasis, dermal angiogenesis, and the development of epidermal hyperplasia: implications for the pathogenesis of psoriasis.

    PubMed

    Elias, Peter M; Arbiser, Jack; Brown, Barbara E; Rossiter, Heidemarie; Man, Mao-Qiang; Cerimele, Francesca; Crumrine, Debra; Gunathilake, Roshan; Choi, Eung Ho; Uchida, Yoshikazu; Tschachler, Erwin; Feingold, Kenneth R

    2008-09-01

    Primary abnormalities in permeability barrier function appear to underlie atopic dermatitis and epidermal trauma; a concomitant barrier dysfunction could also drive other inflammatory dermatoses, including psoriasis. Central to this outside-inside view of disease pathogenesis is the epidermal generation of cytokines/growth factors, which in turn signal downstream epidermal repair mechanisms. Yet, this cascade, if sustained, signals downstream epidermal hyperplasia and inflammation. We found here that acute barrier disruption rapidly stimulates mRNA and protein expression of epidermal vascular endothelial growth factor-A (VEGF-A) in normal hairless mice, a specific response to permeability barrier requirements because up-regulation is blocked by application of a vapor-impermeable membrane. Moreover, epidermal vegf(-/-) mice display abnormal permeability barrier homeostasis, attributable to decreased VEGF signaling of epidermal lamellar body production; a paucity of dermal capillaries with reduced vascular permeability; and neither angiogenesis nor epidermal hyperplasia in response to repeated tape stripping (a model of psoriasiform hyperplasia). These results support a central role for epidermal VEGF in the maintenance of epidermal permeability barrier homeostasis and a link between epidermal VEGF production and both dermal angiogenesis and the development of epidermal hyperplasia. Because psoriasis is commonly induced by external trauma [isomorphic (Koebner) phenomenon] and is associated with a prominent permeability barrier abnormality, excess VEGF production, prominent angiogenesis, and epidermal hyperplasia, these results could provide a potential outside-inside mechanistic basis for the development of psoriasis.

  7. Mechanisms of modulation of brain microvascular endothelial cells function by thrombin.

    PubMed

    Brailoiu, Eugen; Shipsky, Megan M; Yan, Guang; Abood, Mary E; Brailoiu, G Cristina

    2017-02-15

    Brain microvascular endothelial cells are a critical component of the blood-brain barrier. They form a tight monolayer which is essential for maintaining the brain homeostasis. Blood-derived proteases such as thrombin may enter the brain during pathological conditions like trauma, stroke, and inflammation and further disrupts the permeability of the blood-brain barrier, via incompletely characterized mechanisms. We examined the underlying mechanisms evoked by thrombin in rat brain microvascular endothelial cells (RBMVEC). Our results indicate that thrombin, acting on protease-activated receptor 1 (PAR1) increases cytosolic Ca(2+) concentration in RBMVEC via Ca(2+) release from endoplasmic reticulum through inositol 1,4,5-trisphosphate receptors and Ca(2+) influx from extracellular space. Thrombin increases nitric oxide production; the effect is abolished by inhibition of the nitric oxide synthase or by antagonism of PAR1 receptors. In addition, thrombin increases mitochondrial and cytosolic reactive oxygen species production via PAR1-dependent mechanisms. Immunocytochemistry studies indicate that thrombin increases F-actin stress fibers, and disrupts the tight junctions. Thrombin increased the RBMVEC permeability assessed by a fluorescent flux assay. Taken together, our results indicate multiple mechanisms by which thrombin modulates the function of RBMVEC and may contribute to the blood-brain barrier dysfunction.

  8. Adult human dental pulp stem cells promote blood-brain barrier permeability through vascular endothelial growth factor-a expression.

    PubMed

    Winderlich, Joshua N; Kremer, Karlea L; Koblar, Simon A

    2016-06-01

    Stem cell therapy is a promising new treatment option for stroke. Intravascular administration of stem cells is a valid approach as stem cells have been shown to transmigrate the blood-brain barrier. The mechanism that causes this effect has not yet been elucidated. We hypothesized that stem cells would mediate localized discontinuities in the blood-brain barrier, which would allow passage into the brain parenchyma. Here, we demonstrate that adult human dental pulp stem cells express a soluble factor that increases permeability across an in vitro model of the blood-brain barrier. This effect was shown to be the result of vascular endothelial growth factor-a. The effect could be amplified by exposing dental pulp stem cell to stromal-derived factor 1, which stimulates vascular endothelial growth factor-a expression. These findings support the use of dental pulp stem cell in therapy for stroke. © The Author(s) 2015.

  9. Stress worsens endothelial function and ischemic stroke via glucocorticoids.

    PubMed

    Balkaya, Mustafa; Prinz, Vincent; Custodis, Florian; Gertz, Karen; Kronenberg, Golo; Kroeber, Jan; Fink, Klaus; Plehm, Ralph; Gass, Peter; Laufs, Ulrich; Endres, Matthias

    2011-11-01

    Chronic stress is associated with increased stroke risk. However, the underlying pathophysiological mechanisms are poorly understood. We examined the effects of chronic stress on endothelial function and ischemic brain injury in a mouse model. 129/SV mice were treated with glucocorticoid receptor antagonist mifepristone (25 mg kg(-1)/d) or vehicle and exposed to 28 days of chronic stress consisting of exposure to rat, restraint stress, and tail suspension. Heart rate and blood pressure were continuously recorded by telemetry. Endothelial nitric oxide synthase mRNA and protein expression as well as superoxide production and lipid hydroperoxides were quantified. Endothelium-dependent vasorelaxation was measured in aortic rings. Ischemic lesion volume was quantified after 30 minutes filamentous middle cerebral artery occlusion and 72 hours reperfusion. Chronic stress caused a significant increase in heart rate, impaired endothelium-dependent vasorelaxation, increased superoxide production, and reduced aortic and brain endothelial nitric oxide synthase levels. Animals exposed to chronic stress showed major increases in ischemic lesion size. These deleterious effects of stress were completely reversed by treatment with mifepristone. Chronic stress increases stroke vulnerability likely through endothelial dysfunction, which can be reversed by a glucocorticoid receptor antagonist.

  10. Non-invasive Assessment of Microvascular and Endothelial Function

    PubMed Central

    Cheng, Cynthia; Daskalakis, Constantine; Falkner, Bonita

    2013-01-01

    The authors have utilized capillaroscopy and forearm blood flow techniques to investigate the role of microvascular dysfunction in pathogenesis of cardiovascular disease. Capillaroscopy is a non-invasive, relatively inexpensive methodology for directly visualizing the microcirculation. Percent capillary recruitment is assessed by dividing the increase in capillary density induced by postocclusive reactive hyperemia (postocclusive reactive hyperemia capillary density minus baseline capillary density), by the maximal capillary density (observed during passive venous occlusion). Percent perfused capillaries represents the proportion of all capillaries present that are perfused (functionally active), and is calculated by dividing postocclusive reactive hyperemia capillary density by the maximal capillary density. Both percent capillary recruitment and percent perfused capillaries reflect the number of functional capillaries. The forearm blood flow (FBF) technique provides accepted non-invasive measures of endothelial function: The ratio FBFmax/FBFbase is computed as an estimate of vasodilation, by dividing the mean of the four FBFmax values by the mean of the four FBFbase values. Forearm vascular resistance at maximal vasodilation (FVRmax) is calculated as the mean arterial pressure (MAP) divided by FBFmax. Both the capillaroscopy and forearm techniques are readily acceptable to patients and can be learned quickly. The microvascular and endothelial function measures obtained using the methodologies described in this paper may have future utility in clinical patient cardiovascular risk-reduction strategies. As we have published reports demonstrating that microvascular and endothelial dysfunction are found in initial stages of hypertension including prehypertension, microvascular and endothelial function measures may eventually aid in early identification, risk-stratification and prevention of end-stage vascular pathology, with its potentially fatal consequences. PMID

  11. XIAP reverses various functional activities of FRNK in endothelial cells

    SciTech Connect

    Ahn, Sunyoung; Kim, Hyun Jeong; Chi, Sung-Gil; Park, Heonyong

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer FRNK domain is recruited into focal adhesion (FA), controlling endothelial cell adhesion. Black-Right-Pointing-Pointer XIAP binds the FRNK domain of FAK. Black-Right-Pointing-Pointer XIAP inhibits recruitment of FRNK into Fas and FRNK-promoted cell adhesion. Black-Right-Pointing-Pointer XIAP plays a key role in vascular functions of FRNK or FRNK domain-mediated vascular functions of FAK. -- Abstract: In endothelial cells, focal adhesion kinase (FAK) regulates cell proliferation, migration, adhesion, and shear-stimulated activation of MAPK. We recently found that FAK is recruited into focal adhesion (FA) sites through interactions with XIAP (X-chromosome linked inhibitor of apoptosis protein) and activated by Src kinase in response to shear stress. In this study, we examined which domain(s) of FAK is(are) important for various vascular functions such as FA recruiting, XIAP-binding and shear stress-stimulated ERK activation. Through a series of experiments, we determined that the FRNK domain is recruited into FA sites and promotes endothelial cell adhesion. Interestingly, XIAP knockdown was shown to reduce FA recruitment of FRNK and the cell adhesive effect of FRNK. In addition, we found that XIAP interacts with FRNK, suggesting cross-talk between XIAP and FRNK. We also demonstrated that FRNK inhibits endothelial cell migration and shear-stimulated ERK activation. These inhibitory effects of FRNK were reversed by XIAP knockdown. Taken together, we can conclude that XIAP plays a key role in vascular functions of FRNK or FRNK domain-mediated vascular functions of FAK.

  12. Caffeine improves barrier function in male skin.

    PubMed

    Brandner, J M; Behne, M J; Huesing, B; Moll, I

    2006-10-01

    The influence of androgens, especially testosterone and its effector dihydrotestosterone, results in a constitutive disadvantage for male skin, e.g. reduced viability of hair at the scalp and reduced epidermal permeability barrier repair capacity. Dihydrotestosterone can act, among others, as an adenyl cyclase inhibitor. Caffeine on the other hand is an inexpensive and (in regular doses) harmless substance used in various cosmetic products, which can act as a phosphodiesterase inhibitor. To prove the hypothesis that caffeine as a phosphodiesterase inhibitor is able to override testosterone-induced effects on barrier function, we performed a double-blind placebo controlled study with healthy volunteers. In this study, 0.5% caffeine in a hydroxyethylcellulose gel preparation (HEC) was applied on one forearm, HEC without caffeine on the other forearm of male and female volunteers for 7 days and transepidermal water loss (TEWL) was measured before and at the end of the treatment period. Basal TEWL did not differ significantly between male and female subjects but the application of caffeine significantly reduced TEWL in male skin compared with female skin. We conclude that caffeine is beneficial for barrier function in male skin.

  13. Alterations of blood brain barrier function in hyperammonemia: an overview.

    PubMed

    Skowrońska, Marta; Albrecht, Jan

    2012-02-01

    Ammonia is a neurotoxin involved in the pathogenesis of neurological conditions associated with hyperammonemia, including hepatic encephalopathy, a condition associated with acute--(ALF) or chronic liver failure. This article reviews evidence that apart from directly affecting the metabolism and function of the central nervous system cells, ammonia influences the passage of different molecules across the blood brain barrier (BBB). A brief description is provided of the tight junctions, which couple adjacent cerebral capillary endothelial cells to each other to form the barrier. Ammonia modulates the transcellular passage of low-to medium-size molecules, by affecting their carriers located at the BBB. Ammonia induces interrelated aberrations of the transport of the large neutral amino acids and aromatic amino acids (AAA), whose influx is augmented by exchange with glutamine produced in the course of ammonia detoxification, and maybe also modulated by the extracellularly acting gamma-glutamyl moiety transferring enzyme, gamma-glutamyl-transpeptidase. Impaired AAA transport affects neurotransmission by altering intracerebral synthesis of catecholamines (serotonin and dopamine), and producing "false neurotransmitters" (octopamine and phenylethylamine). Ammonia also modulates BBB transport of the cationic amino acids: the nitric oxide precursor, arginine, and ornithine, which is an ammonia trap, and affects the transport of energy metabolites glucose and creatine. Moreover, ammonia acting either directly or in synergy with liver injury-derived inflammatory cytokines also evokes subtle increases of the transcellular passage of molecules of different size (BBB "leakage"), which appears to be responsible for the vasogenic component of cerebral edema associated with ALF.

  14. Loss of Endothelial Barrier in Marfan Mice (mgR/mgR) Results in Severe Inflammation after Adenoviral Gene Therapy

    PubMed Central

    Weymann, Alexander; Arif, Rawa; Weber, Antje; Zaradzki, Marcin; Richter, Karsten; Ensminger, Stephan; Robinson, Peter Nicholas; Wagner, Andreas H.; Karck, Matthias; Kallenbach, Klaus

    2016-01-01

    Objectives Marfan syndrome is an autosomal dominant inherited disorder of connective tissue. The vascular complications of Marfan syndrome have the biggest impact on life expectancy. The aorta of Marfan patients reveals degradation of elastin layers caused by increased proteolytic activity of matrix metalloproteinases (MMPs). In this study we performed adenoviral gene transfer of human tissue inhibitor of matrix metalloproteinases-1 (hTIMP-1) in aortic grafts of fibrillin-1 deficient Marfan mice (mgR/mgR) in order to reduce elastolysis. Methods We performed heterotopic infrarenal transplantation of the thoracic aorta in female mice (n = 7 per group). Before implantation, mgR/mgR and wild-type aortas (WT, C57BL/6) were transduced ex vivo with an adenoviral vector coding for human TIMP-1 (Ad.hTIMP-1) or β-galactosidase (Ad.β-Gal). As control mgR/mgR and wild-type aortas received no gene therapy. Thirty days after surgery, overexpression of the transgene was assessed by immunohistochemistry (IHC) and collagen in situ zymography. Histologic staining was performed to investigate inflammation, the neointimal index (NI), and elastin breaks. Endothelial barrier function of native not virus-exposed aortas was evaluated by perfusion of fluorescent albumin and examinations of virus-exposed tissue were performed by transmission electron microscopy (TEM). Results IHC and ISZ revealed sufficient expression of the transgene. Severe cellular inflammation and intima hyperplasia were seen only in adenovirus treated mgR/mgR aortas (Ad.β-Gal, Ad.hTIMP-1 NI: 0.23; 0.43), but not in native and Ad.hTIMP-1 treated WT (NI: 0.01; 0.00). Compared to native mgR/mgR and Ad.hTIMP-1 treated WT aorta, the NI is highly significant greater in Ad.hTIMP-1 transduced mgR/mgR aorta (p = 0.001; p = 0.001). As expected, untreated Marfan grafts showed significant more elastolysis compared to WT (p = 0.001). However, elastolysis in Marfan aortas was not reduced by adenoviral overexpression of hTIMP-1

  15. Endothelial PECAM-1 and its function in vascular physiology and atherogenic pathology.

    PubMed

    Chistiakov, Dimitry A; Orekhov, Alexander N; Bobryshev, Yuri V

    2016-06-01

    Platelet endothelial cell adhesion molecule (PECAM-1) is highly expressed in vascular cells such as endothelial cells (ECs) and blood-borne cells like platelets and leukocytes. In ECs, this molecule controls junctional and adhesive properties. In physiological conditions, PECAM-1 supports the endothelial barrier function. In inflammation that is observed in vessels affected by atherosclerosis, the function of PECAM-1 is impaired, an event that leads to increased adhesion of neutrophils and other leukocytes to ECs, decreased vascular integrity, and higher leukocyte transmigration to the intima media. PECAM-1 has six extracellular immunoglobulin (Ig)-like domains that support attraction and adhesion of leukocytes to ECs. The cytoplasmic tail of PECAM-1 contains two tyrosine residues (Tyr-663 and Tyr-686) that could be phosphorylated by Src family protein kinases is involved in the intracellular signaling. Actually, those tyrosines are the part of the immunoreceptor tyrosine-based inhibition motifs (ITIMs) that inhibit inflammation. However, in atherosclerosis, the PECAM-1-dependent immune suppression is disturbed. This in turn facilitates recruitment of leukocytes and supports proatherogenic inflammation.

  16. Vitamin D Enhances Corneal Epithelial Barrier Function

    PubMed Central

    Yin, Zhaohong; Pintea, Victorina; Lin, Yanping; Hammock, Bruce D.

    2011-01-01

    Purpose. The purpose of this study was to determine whether 25-hydroxyvitamin D3 (25(OH)D3) and/or its active metabolite, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), can enhance corneal epithelial barrier function. The authors also determined if corneas contain mRNA for the vitamin D receptor (VDR) and 1α-hydroxylase, the enzyme required to convert 25(OH)D3 to 1,25(OH)2D3, and measured vitamin D metabolite concentrations in aqueous and vitreous humor. Methods. RT-PCR was used to examine mouse, rabbit, and human corneal epithelial VDR and 1α-hydroxylase mRNA. Vitamin D metabolites were measured using a selective vitamin D derivatizing agent and mass spectroscopy. Barrier function experiments were performed by measuring inulin permeability (IP) and/or transepithelial resistance (TER) in control, 25(OH)D3-, and 1,25(OH)2D3-treated human and rabbit corneal epithelial monolayers cultured on permeable inserts. Ca2+ was removed, then reintroduced to the culture medium while IP and TER readings were taken. Occludin levels were examined using Western blotting. Results. All corneal samples were positive for both VDR and 1α-hydroxylase mRNA. All vitamin D metabolites except for unhydroxylated vitamin D3 were detected in aqueous and vitreous humor. Epithelial cells showed increased TER, decreased IP, and increased occludin levels when cultured with 25(OH)D3 and 1,25(OH)2D3. Conclusions. We conclude that corneas contain mRNA for VDR and 1α-hydroxylase as well as significant vitamin D concentrations. 25(OH)D3 and its active metabolite 1,25(OH)2D3, both enhance corneal epithelial barrier function. PMID:21715350

  17. Defective barrier function in neosquamous epithelium.

    PubMed

    Jovov, Biljana; Shaheen, Nicholas J; Orlando, Geraldine S; Djukic, Zorka; Orlando, Roy C

    2013-03-01

    Radiofrequency ablation (RFA) of Barrett's esophagus (BE) is a common strategy for the prevention of esophageal adenocarcinoma (EAC). After RFA, the ablated esophagus heals on acid suppressive therapy, and is re-populated with a stratified squamous epithelium, referred to as "neosquamous epithelium (NSE)." Because the ability of the NSE to protect the underlying tissue from recurrent insult by reflux is unclear, we assessed the barrier function of NSE by comparing it to that of the native upper squamous epithelium (USE) in subjects having undergone RFA. At varying intervals following RFA, the barrier function of NSE and USE were assessed in endoscopic biopsies by light and electron microscopy, and by measurement of electrical resistance (R) and fluorescein flux in mini-Ussing chambers. Chamber results were further compared with results from control biopsies (healthy distal esophagus). A claudin expression profile in the tight junctions (TJs) of NSE and USE was determined using Quantitative reverse transcriptase PCR. Differential expression of claudin-4 between NSE and USE was assayed by immunoblots. USE was histologically normal whereas NSE showed dilated intercellular spaces and marked eosinophilia. NSE was also more permeable than USE and healthy controls, having lower mean R and higher fluorescein fluxes. Abnormally low R values for NSE were unrelated to the time period following RFA (or number of prior RFA sessions), being abnormal even 26 months after RFA. Abnormal permeability in NSE was associated with significantly lower values for claudin-4 and claudin-10 than in USE. NSE commonly exhibits defective barrier function. As this defect will make it vulnerable to injury, inflammation, and destruction by acidic and weakly acidic refluxates, it may in part explain incidences of recurrence of BE following ablation.

  18. Hepatocyte growth factor triggers distinct mechanisms of Asef and Tiam1 activation to induce endothelial barrier enhancement.

    PubMed

    Higginbotham, Katherine; Tian, Yufeng; Gawlak, Grzegorz; Moldobaeva, Nurgul; Shah, Alok; Birukova, Anna A

    2014-11-01

    Previous reports described an important role of hepatocyte growth factor (HGF) in mitigation of pulmonary endothelial barrier dysfunction and cell injury induced by pathologic agonists and mechanical forces. HGF protective effects have been associated with Rac-GTPase signaling pathway activated by Rac-specific guanine nucleotide exchange factor Tiam1 and leading to enhancement of intercellular adherens junctions. This study tested involvement of a novel Rac-specific activator, Asef, in endothelial barrier enhancement by HGF and investigated a mechanism of HGF-induced Asef activation. Si-RNA-based knockdown of Tiam1 and Asef had an additive effect on attenuation of HGF-induced Rac activation and endothelial cell (EC) barrier enhancement. Tiam1 and Asef activation was abolished by pharmacologic inhibitors of HGF receptor and PI3-kinase. In contrast to Tiam1, Asef interacted with APC and associated with microtubule fraction upon HGF stimulation. EC treatment by low dose nocodazole to inhibit peripheral microtubule dynamics partially attenuated HGF-induced Asef peripheral translocation, but had negligible effect on Tiam1 translocation. These effects were associated with attenuation of HGF-induced barrier enhancement in EC pretreated with low ND dose and activation of Rac and its cytoskeletal effectors PAK1 and cortactin. These data demonstrate, that in addition to microtubule-independent Tiam1 activation, HGF engages additional microtubule- and APC-dependent pathway of Asef activation. These mechanisms may complement each other to provide the fine tuning of Rac signaling and endothelial barrier enhancement in response to various agonists. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Impaired endothelial function and blood flow in repetitive strain injury.

    PubMed

    Brunnekreef, J; Brunnekreef, J J; Benda, N; Benda, N M M; Schreuder, T; Schreuder, T H A; Hopman, M; Hopman, M T E; Thijssen, D; Thijssen, D H J

    2012-10-01

    Repetitive Strain Injury (RSI) is a disabling upper extremity overuse injury that may be associated with pathophysiological changes in the vasculature. In this study we investigated whether RSI is associated with endothelial dysfunction and impaired exercise-induced blood flow in the affected forearm. 10 patients with RSI (age, 40.2 ± 10.3; BMI, 23.8 ± 3.3) and 10 gender- and age-matched control subjects (age, 38.0 ± 12.4; BMI, 22.7 ± 3.4) participated in this study. Brachial artery blood flow was measured at rest and during 3-min periods of isometric handgrip exercise at 15%, 30% and 45% of the individual maximal voluntary contraction. Brachial artery endothelial function was assessed as the flow mediated dilation (FMD), by measuring brachial artery diameter and velocity before and after 5-min ischemic occlusion. We found a lower exercise-induced brachial artery blood flow in patients with RSI than in controls (p=0.04). Brachial artery FMD was significantly lower in patients with RSI than in controls (p<0.01), whilst a lower FMD was also found in patient with unilateral RSI when comparing the affected arm with the non-affected arm (p=0.04). Our results suggest that patients with RSI have an attenuated exercise-induced blood flow and an impaired endothelial function in the affected arm. These findings importantly improve our understanding of the pathophysiological mechanism of RSI.

  20. Metoprolol Improves Endothelial Function in Patients with Cardiac Syndrome X

    PubMed Central

    Majidinia, Maryam; Rasmi, Yousef; Khadem Ansari, Mohammad Hassan; Seyed-Mohammadzad, MirHossein; Saboory, Ehsan; Shirpoor, Alireza

    2016-01-01

    Endothelial dysfunction which is manifested by the loss of nitric oxide bioavailability, is an increasingly recognized cause of cardiac syndrome X (CSX) and beta blockers are used for the treatment of this syndrome. Thus, the aim of this study was to investigate effects of metoprolol, as a beta blocker, on endothelial function in CSX patients. The study included 25 CSX patients (20 female/ 5 male, mean age: 55.36±10.31 years) who received metoprolol (50 mg BID) for one month. In addition, 25 healthy controls (20 female/ 5 male, mean age: 54.32 ±9.27 years) were enrolled. Levels of endothelin-1, E-selectin, and vascular cell adhesion molecule-1 (VCAM-1) in controls and CSX patients were measured, both at the baseline and after the treatment, by the enzyme-linked immunosorbent assay. In CSX patients, at the baseline, levels of E-selectin and VCAM-1 were significantly higher than those of the controls. In addition, levels of these biomarkers in CSX patients after the treatment significantly decreased compared to the baseline. In spite of similar tendency, these differences were not significant for endothelin-1. In conclusion, metoprolol therapy improves endothelial function. Thus, it may be a suggested choice for CSX treatment. However, further studies are needed to confirm the clinical significance of metoprolol therapy for CSX patients. PMID:27980592

  1. Endothelial function in patients with migraine during the interictal period.

    PubMed

    Silva, Federico A; Rueda-Clausen, Christian F; Silva, Sandra Y; Zarruk, Juan G; Guzmán, Juan C; Morillo, Carlos A; Vesga, Boris; Pradilla, Gustavo; Flórez, Mildred; López-Jaramillo, Patricio

    2007-01-01

    The aim of this study is to evaluate endothelial function in migraineurs subjects during the asymptomatic period. Migraine has been proposed as a risk factor for cerebrovascular events. The underlying mechanisms that relate these 2 pathologies are unknown. Nitric oxide (NO) has been proposed as the final causative molecule of migraine. Increased NO metabolites concentrations have been reported in migraineurs subjects during acute migraine attacks, but there is no evidence indicating alterations in endothelial NO release during the symptom free period in theses subjects. Fifty migraineurs subjects and 25 healthy subjects matched by gender and age were included. Every subject underwent a complete examination that included medical history, physical examination, resting electrocardiogram, forearm flow-mediated vasodilation (FMD), blood determinations of fasting nitrates and nitrites (NO(2) (-)+ NO(3) (-)), glucose, lipid profile, creatinine, C-reactive protein, and blood cell count. No differences in FMD or NO(2) (-)+ NO(3) (-) were detected among groups. The only difference between migraineurs and control subjects was a higher mean blood pressure 92.1 (8.8) mmHg versus 86.7 (8.2) mmHg P= .01. The endothelial function is not altered during the interictal period in migraineurs subjects.

  2. Hypoxia-induced oxygen tolerance: maintenance of endothelial metabolic function

    SciTech Connect

    Jackson, R.M.; Ann, H.S.; Oparil, S.

    1988-01-01

    Hypoxia (10%-12% O2) preadaptation for 4-7 days effectively protects rats from oxygen toxicity. The present study was designed to investigate the hypothesis that the lung's microvascular endothelium shares in development of oxygen tolerance and therefore that endothelial metabolic function would be protected from oxygen toxicity by prior adaptation to hypoxia. Since pulmonary oxygen toxicity decreases lung capillary angiotensin converting enzyme (ACE) activity, we assayed converting enzyme active sites in an isolated perfused rat lung preparation as a marker for the development of oxygen toxicity and tolerance. Rats were exposed to air, hypoxia (10% O2 for 4 days), hyperoxia (greater than 95% O2 for 2 days) alone, or hypoxia followed immediately by hyperoxia. Lung vascular ACE content was quantitated by measuring the single pass binding of an iodinated-converting enzyme inhibitor, 125I-MK351A, a derivative of lisinopril. Hypoxia adaptation per se had no effect on ACE content reflected in normal 125I-MK351A binding, whereas hyperoxia exposure caused a significant decrease in lung vascular ACE. Hyperoxia-induced decreases in ACE content were prevented partially by hypoxia adaptation, indicating that ACE content on luminal endothelial surfaces was protected from oxygen toxicity. In isolated perfused lungs 125I-MK351A binding reflects development of oxygen tolerance after hypoxia preadaptation and suggests that lung endothelial metabolic function is protected from oxygen toxicity.

  3. An integrative microfluidically supported in vitro model of an endothelial barrier combined with cortical spheroids simulates effects of neuroinflammation in neocortex development.

    PubMed

    Raasch, Martin; Rennert, Knut; Jahn, Tobias; Gärtner, Claudia; Schönfelder, Gilbert; Huber, Otmar; Seiler, Andrea E M; Mosig, Alexander S

    2016-07-01

    The development of therapeutic substances to treat diseases of the central nervous system is hampered by the tightness and selectivity of the blood-brain barrier. Moreover, testing of potential drugs is time-consuming and cost-intensive. Here, we established a new microfluidically supported, biochip-based model of the brain endothelial barrier in combination with brain cortical spheroids suitable to detect effects of neuroinflammation upon disruption of the endothelial layer in response to inflammatory signals. Unilateral perfusion of the endothelial cell layer with a cytokine mix comprising tumor necrosis factor, IL-1β, IFNγ, and lipopolysaccharide resulted in a loss of endothelial von Willebrand factor and VE-cadherin expression accompanied with an increased leakage of the endothelial layer and diminished endothelial cell viability. In addition, cytokine treatment caused a loss of neocortex differentiation markers Tbr1, Tbr2, and Pax6 in the cortical spheroids concomitant with reduced cell viability and spheroid integrity. From these observations, we conclude that our endothelial barrier/cortex model is suitable to specifically reflect cytokine-induced effects on barrier integrity and to uncover damage and impairment of cortical tissue development and viability. With all its limitations, the model represents a novel tool to study cross-communication between the brain endothelial barrier and underlying cortical tissue that can be utilized for toxicity and drug screening studies focusing on inflammation and neocortex formation.

  4. Activation of cannabinoid receptor 2 attenuates leukocyte-endothelial cell interactions and blood-brain barrier dysfunction under inflammatory conditions.

    PubMed

    Ramirez, Servio H; Haskó, János; Skuba, Andrew; Fan, Shongshan; Dykstra, Holly; McCormick, Ryan; Reichenbach, Nancy; Krizbai, Istvan; Mahadevan, Anu; Zhang, Ming; Tuma, Ronald; Son, Young-Jin; Persidsky, Yuri

    2012-03-21

    Previous studies have shown that modulation of the receptor-mediated cannabinoid system during neuroinflammation can produce potent neuroprotective and anti-inflammatory effects. However, in this context, little is known about how selective activation of the cannabinoid type-2 receptor (CB2R) affects the activated state of the brain endothelium and blood-brain barrier (BBB) function. Using human brain tissues and primary human brain microvascular endothelial cells (BMVECs), we demonstrate that the CB2R is highly upregulated during inflammatory insult. We then examined whether the CB2R agonists could attenuate inflammatory responses at the BBB using a mouse model of LPS-induced encephalitis and highly selective CB2R agonists. Visualization by intravital microscopy revealed that administration of JWH133 [(6aR,10aR)-3-(1,1-dimethylbutyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran] or a novel resorcinol-based compound, O-1966 (1-[4-(1,1-dimethyl-heptyl)-2,6-dimethoxy-phenyl]-3-methyl-cyclohexanol), greatly attenuated leukocyte adhesion in surface pial vessels and in deep ascending cortical postcapillary venules. BBB permeability assessments with small and large fluorescent tracers showed that CB2R agonists were effective at preventing barrier leakiness after LPS administration. To determine whether the effects by CB2R agonists on barrier protection are not only due to the CB2R modulation of immune cell function, we tested the agonists in vitro with barrier-forming primary BMVECs. Remarkably, the addition of CB2R agonist increased transendothelial electrical resistance and increased the amount of tight junction protein present in membrane fractions. Furthermore, CB2R agonists decreased the induction of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 surface expression in BMVECs exposed to various proinflammatory mediators. Together, these results suggest that pharmacological CB2R ligands offer a new strategy for BBB protection

  5. Cytokine Signaling Modulates Blood-Brain Barrier Function

    PubMed Central

    Pan, Weihong; Stone, Kirsten P.; Hsuchou, Hung; Manda, Vamshi K.; Zhang, Yan; Kastin, Abba J.

    2014-01-01

    The blood-brain barrier (BBB) provides a vast interface for cytokines to affect CNS function. The BBB is a target for therapeutic intervention. It is essential, therefore, to understand how cytokines interact with each other at the level of the BBB and how secondary signals modulate CNS functions beyond the BBB. The interactions between cytokines and lipids, however, have not been fully addressed at the level of the BBB. Here, we summarize current understanding of the localization of cytokine receptors and transporters in specific membrane microdomains, particularly lipid rafts, on the luminal (apical) surface of the microvascular endothelial cells composing the BBB. We then illustrate the clinical context of cytokine effects on the BBB by neuroendocrine regulation and amplification of inflammatory signals. Two unusual aspects discussed are signaling crosstalk by different classes of cytokines and genetic regulation of drug efflux transporters. We also introduce a novel area of focus on how cytokines may act through nuclear hormone receptors to modulate efflux transporters and other targets. A specific example discussed is the ATP-binding cassette transporter-1 (ABCA-1) that regulates lipid metabolism. Overall, cytokine signaling at the level of the BBB is a crucial feature of the dynamic regulation that can rapidly change BBB function and affect brain health and disease. PMID:21834767

  6. The Balance Between Metalloproteinases and TIMPs: Critical Regulator of Microvascular Endothelial Cell Function in Health and Disease.

    PubMed

    Masciantonio, Marcello G; Lee, Christopher K S; Arpino, Valerie; Mehta, Sanjay; Gill, Sean E

    2017-01-01

    Endothelial cells (EC), especially the microvascular EC (MVEC), have critical functions in health and disease. For example, healthy MVEC provide a barrier between the fluid and protein found within the blood, and the surrounding tissue. Following tissue injury or infection, the microvascular barrier is often disrupted due to activation and dysfunction of the MVEC. Multiple mechanisms promote MVEC activation and dysfunction, including stimulation by cytokines, mechanical interaction with activated leukocytes, and exposure to harmful leukocyte-derived molecules, which collectively result in a loss of MVEC barrier function. However, MVEC activation is also critical to facilitate recruitment of inflammatory cells, such as neutrophils (PMNs) and monocytes, into the injured or infected tissue. Metalloproteinases, including the matrix metalloproteinases (MMPs) and the closely related, a disintegrin and metalloproteinases (ADAMs), have been implicated in regulating both MVEC barrier function, through cleavage of adherens and tight junctions proteins between adjacent MVEC and through degradation of the extracellular matrix, as well as PMN-MVEC interaction, through shedding of cell surface PMN receptors. Moreover, the tissue inhibitors of metalloproteinases (TIMPs), which collectively inhibit most MMPs and ADAMs, are critical regulators of MVEC activation and dysfunction through their ability to inhibit metalloproteinases and thereby promote MVEC stability. However, TIMPs have been also found to modulate MVEC function through metalloproteinase-independent mechanisms, such as regulation of vascular endothelial growth factor signaling. This chapter is focused on examining the role of the metalloproteinases and TIMPs in regulation of MVEC function in both health and disease. © 2017 Elsevier Inc. All rights reserved.

  7. The balance between Gαi-Cdc42/Rac and Gα12/13-RhoA pathways determines endothelial barrier regulation by Sphingosine-1-Phosphate.

    PubMed

    Reinhard, Nathalie R; Mastop, Marieke; Yin, Taofei; Wu, Yi; Bosma, Esmeralda K; Gadella, Theodorus W J; Goedhart, Joachim; Hordijk, Peter L

    2017-09-27

    The bioactive sphingolipid S1P is present in plasma, bound to carrier proteins, and is involved in many physiological processes, including angiogenesis, inflammatory responses and vascular stabilization. S1P can bind to several G-protein-coupled receptors (GPCRs) activating a number of different signalling networks. At present, the dynamics and relative importance of signalling events activated immediately downstream of GPCR activation are unclear. To examine this, we used a set of FRET-based biosensors for different RhoGTPases (Rac1, RhoA/B/C, Cdc42) as well as for heterotrimeric G-proteins in a series of live-cell imaging experiments in primary human endothelial cells. These experiments were accompanied by biochemical GTPase activity assays and transendothelial resistance measurements. We show that S1P promotes cell spreading and endothelial barrier function through S1PR1-Gαi-Rac1 and S1PR1-Gαi-Cdc42 pathways. In parallel, a S1PR2-Gα12/13-RhoA pathway is activated which can induce cell contraction and loss of barrier function, but only if Gαi-mediated signalling is suppressed. Our results suggest that Gαq activity is not involved in S1P-mediated regulation of barrier integrity. Moreover, we show that early activation of RhoA by S1P inactivates Rac1, but not Cdc42, and vice versa. Together, our data show that the rapid S1P-induced increase in endothelial integrity is mediated by a S1PR1-Gαi-Cdc42 pathway. © 2017 by The American Society for Cell Biology.

  8. Functional CB1 cannabinoid receptors in human vascular endothelial cells.

    PubMed Central

    Liu, J; Gao, B; Mirshahi, F; Sanyal, A J; Khanolkar, A D; Makriyannis, A; Kunos, G

    2000-01-01

    Cannabinoid CB1 receptor mRNA was detected using reverse transcription-polymerase chain reaction (RT-PCR) in endothelial cells from human aorta and hepatic artery and in the ECV304 cell line derived from human umbilical vein endothelial cells. CB1 receptor-binding sites were detected by the high-affinity antagonist radioligand [(125)I]AM-251. In ECV304 cells, both the highly potent synthetic cannabinoid agonist HU-210 and the endogenous ligand anandamide induce activation of mitogen-activated protein (MAP) kinase, and the effect of HU-210 was completely blocked, whereas the effect of anandamide was partially inhibited by SR141716A, a selective CB1 receptor antagonist. Transfection of ECV304 cells with CB1 receptor antisense, but not sense, oligonucleotides caused the same pattern of inhibition as SR141716A. This provides more definitive evidence for the involvement of CB1 receptors in MAP kinase activation and suggests that anandamide may also activate MAP kinase via an additional, CB1 receptor-independent, SR141716A-resistant mechanism. The MAP kinase activation by anandamide in ECV304 cells requires genistein-sensitive tyrosine kinases and protein kinase C (PKC), and anandamide also activates p38 kinase and c-Jun kinase. These findings indicate that CB1 receptors located in human vascular endothelium are functionally coupled to the MAP kinase cascade. Activation of protein kinase cascades by anandamide may be involved in the modulation of endothelial cell growth and proliferation. PMID:10698714

  9. Trafficking of Endogenous Immunoglobulins by Endothelial Cells at the Blood-Brain Barrier

    PubMed Central

    Villaseñor, Roberto; Ozmen, Laurence; Messaddeq, Nadia; Grüninger, Fiona; Loetscher, Hansruedi; Keller, Annika; Betsholtz, Christer; Freskgård, Per-Ola; Collin, Ludovic

    2016-01-01

    The Blood-Brain Barrier (BBB) restricts access of large molecules to the brain. The low endocytic activity of brain endothelial cells (BECs) is believed to limit delivery of immunoglobulins (IgG) to the brain parenchyma. Here, we report that endogenous mouse IgG are localized within intracellular vesicles at steady state in BECs in vivo. Using high-resolution quantitative microscopy, we found a fraction of endocytosed IgG in lysosomes. We observed that loss of pericytes (key components of the BBB) in pdgf-bret/ret mice affects the intracellular distribution of endogenous mouse IgG in BECs. In these mice, endogenous IgG was not detected within lysosomes but instead accumulate at the basement membrane and brain parenchyma. Such IgG accumulation could be due to reduced lysosomal clearance and increased sorting to the abluminal membrane of BECs. Our results suggest that, in addition to low uptake from circulation, IgG lysosomal degradation may be a downstream mechanism by which BECs further restrict IgG access to the brain. PMID:27149947

  10. Correlation between Diastolic Function and Endothelial Function in Patients with Type 2 Diabetes and Hypertension

    PubMed Central

    Bedirian, Ricardo; Neves, Mario Fritsch; Oigman, Wille; Gismondi, Ronaldo Altenburg Odebrecht Curi; Pozzobon, Cesar Romaro; Ladeira, Marcia Cristina Boaventura; Castier, Marcia Bueno

    2016-01-01

    Background: Endothelial dysfunction may be involved in the pathophysiology of cardiac abnormalities in patients with diabetes mellitus (DM). A correlation between endothelial dysfunction and diastolic dysfunction in patients with type 1 DM has been demonstrated, but this relationship has not been well investigated in type 2 DM. Objective: Compare groups of patients with type 2 DM and hypertension with and without diastolic dysfunction using endothelial function indexes, and to assess whether correlations exist between the diastolic function and the endothelial function indexes. Method: This was a cross-sectional study of 34 men and women with type 2 DM and hypertension who were aged between 40 and 70 years and were categorized based on assessments of their Doppler echocardiographic parameters as having normal (14 patients) and abnormal (20 patients) diastolic function. Flow-mediated dilatation (FMD) assessments of the brachial artery evaluated the patients’ endothelial function. Results: The mean maximum FMD was 7.15 ± 2.80% for the patients with diastolic dysfunction and it was 11.85 ± 4.77% for the patients with normal diastolic function (p = 0.004). Correlations existed between the maximum FMD and the E/e' ratio (p = 0.040, r = -0.354) and the early wave velocity (e') at the lateral mitral annulus (p = 0.002, r = 0.509). Conclusion: The endothelial function assessed by FMD was worse in hypertensive diabetic patients with diastolic dysfunction. There were correlations between the diastolic function indexes and the endothelial function indexes in our sample. PMID:27867429

  11. Gastric barrier function and toxic damage.

    PubMed

    Niv, Yaron; Banić, Marko

    2014-01-01

    Gastric epithelium is the first significant barrier between the inner body and the potentially toxic material in the lumen. Nutrients affect gastric barrier continuously--alcohol, coffee, spices, salted food, etc. Also, very potent noxious agents are widely prescribed drugs--nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin and selective serotonin reuptake inhibitors. Helicobacter pylori is a well-known and well-investigated pathogen associated with serious gastric damage and gastric carcinoma. For its defense and maintenance of homeostasis and integrity, except acid secretion and maintenance of low luminal pH, gastric mucosa also has a specific structure, and its function is influenced by different control mechanisms. These include control of mucosal blood flow, control of mucus and bicarbonate secretion, constant cell renewal, and neuronal and hormonal control of defense mechanisms. These mechanisms are mediated by prostaglandins, nitric oxide, growth factors, heat-shock proteins and a neuropeptide called calcitonin gene-related protein. Adrenal glucocorticoids and the central nervous system also play an important role in regulating gastro-protection, especially hypothalamus and the dorsal vagal complex. Gastric mucosa is also an important component of the body's immune system and gut-associated lymphoid tissue which serves as the initiation site for antigen-specific humoral and cell-mediated immune response. Treatment options for gastric barrier dysfunction and damage due to aforementioned noxious agents are guided by the nature of damage and our understanding of the pathophysiological mechanisms involved. Currently, management is guideline driven and depends upon eradication treatment in patients infected with H. pylori and treatment or prevention of aspirin or NSAID ulceration. © 2014 S. Karger AG, Basel.

  12. Sleep Restriction Impairs Blood–Brain Barrier Function

    PubMed Central

    He, Junyun; Hsuchou, Hung; He, Yi; Kastin, Abba J.; Wang, Yuping

    2014-01-01

    The blood–brain barrier (BBB) is a large regulatory and exchange interface between the brain and peripheral circulation. We propose that changes of the BBB contribute to many pathophysiological processes in the brain of subjects with chronic sleep restriction (CSR). To achieve CSR that mimics a common pattern of human sleep loss, we quantified a new procedure of sleep disruption in mice by a week of consecutive sleep recording. We then tested the hypothesis that CSR compromises microvascular function. CSR not only diminished endothelial and inducible nitric oxide synthase, endothelin1, and glucose transporter expression in cerebral microvessels of the BBB, but it also decreased 2-deoxy-glucose uptake by the brain. The expression of several tight junction proteins also was decreased, whereas the level of cyclooxygenase-2 increased. This coincided with an increase of paracellular permeability of the BBB to the small tracers sodium fluorescein and biotin. CSR for 6 d was sufficient to impair BBB structure and function, although the increase of paracellular permeability returned to baseline after 24 h of recovery sleep. This merits attention not only in neuroscience research but also in public health policy and clinical practice. PMID:25355222

  13. Sleep restriction impairs blood-brain barrier function.

    PubMed

    He, Junyun; Hsuchou, Hung; He, Yi; Kastin, Abba J; Wang, Yuping; Pan, Weihong

    2014-10-29

    The blood-brain barrier (BBB) is a large regulatory and exchange interface between the brain and peripheral circulation. We propose that changes of the BBB contribute to many pathophysiological processes in the brain of subjects with chronic sleep restriction (CSR). To achieve CSR that mimics a common pattern of human sleep loss, we quantified a new procedure of sleep disruption in mice by a week of consecutive sleep recording. We then tested the hypothesis that CSR compromises microvascular function. CSR not only diminished endothelial and inducible nitric oxide synthase, endothelin1, and glucose transporter expression in cerebral microvessels of the BBB, but it also decreased 2-deoxy-glucose uptake by the brain. The expression of several tight junction proteins also was decreased, whereas the level of cyclooxygenase-2 increased. This coincided with an increase of paracellular permeability of the BBB to the small tracers sodium fluorescein and biotin. CSR for 6 d was sufficient to impair BBB structure and function, although the increase of paracellular permeability returned to baseline after 24 h of recovery sleep. This merits attention not only in neuroscience research but also in public health policy and clinical practice.

  14. An in vitro and in vivo study of peptide-functionalized nanoparticles for brain targeting: The importance of selective blood-brain barrier uptake.

    PubMed

    Bode, Gerard H; Coué, Gregory; Freese, Christian; Pickl, Karin E; Sanchez-Purrà, Maria; Albaiges, Berta; Borrós, Salvador; van Winden, Ewoud C; Tziveleka, Leto-Aikaterini; Sideratou, Zili; Engbersen, Johan F J; Singh, Smriti; Albrecht, Krystyna; Groll, Jürgen; Möller, Martin; Pötgens, Andy J G; Schmitz, Christoph; Fröhlich, Eleonore; Grandfils, Christian; Sinner, Frank M; Kirkpatrick, C James; Steinbusch, Harry W M; Frank, Hans-Georg; Unger, Ronald E; Martinez-Martinez, Pilar

    2016-11-21

    Targeted delivery of drugs across endothelial barriers remains a formidable challenge, especially in the case of the brain, where the blood-brain barrier severely limits entry of drugs into the central nervous system. Nanoparticle-mediated transport of peptide/protein-based drugs across endothelial barriers shows great potential as a therapeutic strategy in a wide variety of diseases. Functionalizing nanoparticles with peptides allows for more efficient targeting to specific organs. We have evaluated the hemocompatibilty, cytotoxicity, endothelial uptake, efficacy of delivery and safety of liposome, hyperbranched polyester, poly(glycidol) and acrylamide-based nanoparticles functionalized with peptides targeting brain endothelial receptors, in vitro and in vivo. We used an ELISA-based method for the detection of nanoparticles in biological fluids, investigating the blood clearance rate and in vivo biodistribution of labeled nanoparticles in the brain after intravenous injection in Wistar rats. Herein, we provide a detailed report of in vitro and in vivo observations.

  15. Organization of Endothelial Cells, Pericytes, and Astrocytes into a 3D Microfluidic in Vitro Model of the Blood-Brain Barrier.

    PubMed

    Wang, Jack D; Khafagy, El-Sayed; Khanafer, Khalil; Takayama, Shuichi; ElSayed, Mohamed E H

    2016-03-07

    The endothelial cells lining the capillaries supplying the brain with oxygen and nutrients form a formidable barrier known as the blood-brain barrier (BBB), which exhibits selective permeability to small drug molecules and virtually impermeable to macromolecular therapeutics. Current in vitro BBB models fail to replicate this restrictive behavior due to poor integration of the endothelial cells with supporting cells (pericytes and astrocytes) following the correct anatomical organization observed in vivo. We report the coculture of mouse brain microvascular endothelial cells (b.End3), pericytes, with/without C8-D1A astrocytes in layered microfluidic channels forming three-dimensional (3D) bi- and triculture models of the BBB. The live/dead assay indicated high viability of all cultured cells up to 21 days. Trans-endothelial electrical resistance (TEER) values confirmed the formation of intact monolayers after 3 days in culture and showed statistically higher values for the triculture model compared to the single and biculture models. Screening the permeability of [(14)C]-mannitol and [(14)C]-urea showed the ability of bi- and triculture models to discriminate between different markers based on their size. Further, permeability of [(14)C]-mannitol across the triculture model after 18 days in culture matched its reported permeability across the BBB in vivo. Mathematical calculations also showed that the radius of the tight junctions pores (R) in the triculture model is similar to the reported diameter of the BBB in vivo. Finally, both the bi- and triculture models exhibited functional expression of the P-glycoprotein efflux pump, which increased with the increase in the number of days in culture. These results collectively indicate that the triculture model is a robust in vitro model of the BBB.

  16. Drugs of abuse and blood-brain barrier endothelial dysfunction: A focus on the role of oxidative stress

    PubMed Central

    Sajja, Ravi K; Rahman, Shafiqur

    2015-01-01

    Psychostimulants and nicotine are the most widely abused drugs with a detrimental impact on public health globally. While the long-term neurobehavioral deficits and synaptic perturbations are well documented with chronic use of methamphetamine, cocaine, and nicotine, emerging human and experimental studies also suggest an increasing incidence of neurovascular complications associated with drug abuse. Short- or long-term administration of psychostimulants or nicotine is known to disrupt blood-brain barrier (BBB) integrity/function, thus leading to an increased risk of brain edema and neuroinflammation. Various pathophysiological mechanisms have been proposed to underlie drug abuse-induced BBB dysfunction suggesting a central and unifying role for oxidative stress in BBB endothelium and perivascular cells. This review discusses drug-specific effects of methamphetamine, cocaine, and tobacco smoking on brain microvascular crisis and provides critical assessment of oxidative stress-dependent molecular pathways focal to the global compromise of BBB. Additionally, given the increased risk of human immunodeficiency virus (HIV) encephalitis in drug abusers, we have summarized the synergistic pathological impact of psychostimulants and HIV infection on BBB integrity with an emphasis on unifying role of endothelial oxidative stress. This mechanistic framework would guide further investigations on specific molecular pathways to accelerate therapeutic approaches for the prevention of neurovascular deficits by drugs of abuse. PMID:26661236

  17. Drugs of abuse and blood-brain barrier endothelial dysfunction: A focus on the role of oxidative stress.

    PubMed

    Sajja, Ravi K; Rahman, Shafiqur; Cucullo, Luca

    2016-03-01

    Psychostimulants and nicotine are the most widely abused drugs with a detrimental impact on public health globally. While the long-term neurobehavioral deficits and synaptic perturbations are well documented with chronic use of methamphetamine, cocaine, and nicotine, emerging human and experimental studies also suggest an increasing incidence of neurovascular complications associated with drug abuse. Short- or long-term administration of psychostimulants or nicotine is known to disrupt blood-brain barrier (BBB) integrity/function, thus leading to an increased risk of brain edema and neuroinflammation. Various pathophysiological mechanisms have been proposed to underlie drug abuse-induced BBB dysfunction suggesting a central and unifying role for oxidative stress in BBB endothelium and perivascular cells. This review discusses drug-specific effects of methamphetamine, cocaine, and tobacco smoking on brain microvascular crisis and provides critical assessment of oxidative stress-dependent molecular pathways focal to the global compromise of BBB. Additionally, given the increased risk of human immunodeficiency virus (HIV) encephalitis in drug abusers, we have summarized the synergistic pathological impact of psychostimulants and HIV infection on BBB integrity with an emphasis on unifying role of endothelial oxidative stress. This mechanistic framework would guide further investigations on specific molecular pathways to accelerate therapeutic approaches for the prevention of neurovascular deficits by drugs of abuse. © The Author(s) 2015.

  18. Microbubbles shunting via a patent foramen ovale impair endothelial function

    PubMed Central

    Fok, Henry; Jiang, Benyu; Chowienczyk, Phil

    2015-01-01

    Objectives Exposure to intravascular microbubbles after diving and during medical procedures alters endothelial function. The aim of this study was to investigate whether a patent foramen ovale altered forearm endothelial function by facilitating microbubbles transfer. Design Patients attended on two separate visits, at least seven days apart receiving agitated saline or no active intervention in random order. On both days, flow-mediated dilatation of the brachial artery was measured using vascular ultrasound. On the intervention visit, agitated saline was injected and the passage of microbubbles into the arterial circulation was confirmed by echocardiography. Serial flow-mediated dilatation measurements were made after agitated saline and at the same time points after no intervention. Setting St Thomas’ Hospital in London. Participants Patients with a patent foramen ovale (PFO+n = 14, 9 male, mean ± SD age 42.2 ± 10.5 years) and patients without a patent foramen ovale (PFO− n = 10, 7 male, mean ± SD age 49.4 ± 18.4 years) were recruited. Main outcome measures Change in brachial artery flow-mediated dilatation. Results In patent foramen ovale + patients, flow-mediated dilatation did not change significantly on the control day but after agitated saline reduced by 2.3 ± 0.3%, 20 minutes after bubble injection (P < 0.005 vs. corresponding change in flow-mediated dilatation during control study). There was no significant change in flow-mediated dilatation for patent foramen ovale− patients at either visit. Conclusion These results suggest that the presence of a patent foramen ovale facilitated impairment of endothelial function acutely by the transfer of microbubbles into the arterial circulation. As a patent foramen ovale is a common condition, this may be relevant to microbubbles exposure in medical procedures and in decompression illness. PMID:26668739

  19. Microbubbles shunting via a patent foramen ovale impair endothelial function.

    PubMed

    Fok, Henry; Jiang, Benyu; Chowienczyk, Phil; Clapp, Brian

    2015-01-01

    Exposure to intravascular microbubbles after diving and during medical procedures alters endothelial function. The aim of this study was to investigate whether a patent foramen ovale altered forearm endothelial function by facilitating microbubbles transfer. Patients attended on two separate visits, at least seven days apart receiving agitated saline or no active intervention in random order. On both days, flow-mediated dilatation of the brachial artery was measured using vascular ultrasound. On the intervention visit, agitated saline was injected and the passage of microbubbles into the arterial circulation was confirmed by echocardiography. Serial flow-mediated dilatation measurements were made after agitated saline and at the same time points after no intervention. St Thomas' Hospital in London. Patients with a patent foramen ovale (PFO+n = 14, 9 male, mean ± SD age 42.2 ± 10.5 years) and patients without a patent foramen ovale (PFO- n = 10, 7 male, mean ± SD age 49.4 ± 18.4 years) were recruited. Change in brachial artery flow-mediated dilatation. In patent foramen ovale + patients, flow-mediated dilatation did not change significantly on the control day but after agitated saline reduced by 2.3 ± 0.3%, 20 minutes after bubble injection (P < 0.005 vs. corresponding change in flow-mediated dilatation during control study). There was no significant change in flow-mediated dilatation for patent foramen ovale- patients at either visit. These results suggest that the presence of a patent foramen ovale facilitated impairment of endothelial function acutely by the transfer of microbubbles into the arterial circulation. As a patent foramen ovale is a common condition, this may be relevant to microbubbles exposure in medical procedures and in decompression illness.

  20. Black tea improves endothelial function in renal transplant recipients.

    PubMed

    Ardalan, M R; Tarzamni, M K; Shoja, M M; Tubbs, R S; Rahimi-Ardabili, B; Ghabili, K; Khosroshahi, H T

    2007-05-01

    Endothelial damage and dysfunction are commonplace in renal transplant recipients. Impaired endothelial function is an important contributor to cardiovascular diseases. We hypothesized that short-term black tea consumption may improve endothelium-dependent arterial dilation in kidney recipients. Fifteen recipients were studied on an outpatient basis in a single, university-affiliated clinic. Inclusion criteria were stable and good allograft function. The main exclusion criteria were uncontrolled hypertension, smoking, alcohol consumption, coffee drinking, diabetes mellitus, and coronary artery disease, or a history of upper limb vascular manipulations. After overnight fasting, the brachial artery diameter (BAD) was measured at the end of diastole using an ultrasound machine before (basal BAD) and 1 minute after temporary ( approximately 3 minutes) external occlusion (posthyperemia BAD). Flow-mediated vasodilation (FMV) and percent of FMV (FMV%) were calculated by appropriate formula. FMV and FMV% were determined at baseline and 2 hours after consuming 0.5 L freshly brewed black tea. For control, the study was repeated for each patient the next day and FMV and FMV% were determined before and 2 hours after consuming 0.5 L of water. The men age of patients was 37.2 +/- 9.7 years (range, 25 to 50) with a male:female ratio of 3:2. Patients were 26.8 +/- 10.6 months postrenal transplantation. Black tea consumption significantly increased posthyperemia BAD, FMV, and FMV% (P<.05). However, water consumption did not alter the basal or posthyperemia BAD, FMV, or FMV% (P>.05). Based on our study, short-term consumption of black tea may improve endothelial function and endothelium-dependent arterial vasodilation in renal transplant recipients.

  1. Inhibition of Rho-kinase protects cerebral barrier from ischaemia-evoked injury through modulations of endothelial cell oxidative stress and tight junctions.

    PubMed

    Gibson, Claire L; Srivastava, Kirtiman; Sprigg, Nikola; Bath, Philip M W; Bayraktutan, Ulvi

    2014-06-01

    Ischaemic strokes evoke blood-brain barrier (BBB) disruption and oedema formation through a series of mechanisms involving Rho-kinase activation. Using an animal model of human focal cerebral ischaemia, this study assessed and confirmed the therapeutic potential of Rho-kinase inhibition during the acute phase of stroke by displaying significantly improved functional outcome and reduced cerebral lesion and oedema volumes in fasudil- versus vehicle-treated animals. Analyses of ipsilateral and contralateral brain samples obtained from mice treated with vehicle or fasudil at the onset of reperfusion plus 4 h post-ischaemia or 4 h post-ischaemia alone revealed these benefits to be independent of changes in the activity and expressions of oxidative stress- and tight junction-related parameters. However, closer scrutiny of the same parameters in brain microvascular endothelial cells subjected to oxygen-glucose deprivation ± reperfusion revealed marked increases in prooxidant NADPH oxidase enzyme activity, superoxide anion release and in expressions of antioxidant enzyme catalase and tight junction protein claudin-5. Cotreatment of cells with Y-27632 prevented all of these changes and protected in vitro barrier integrity and function. These findings suggest that inhibition of Rho-kinase after acute ischaemic attacks improves cerebral integrity and function through regulation of endothelial cell oxidative stress and reorganization of intercellular junctions. Inhibition of Rho-kinase (ROCK) activity in a mouse model of human ischaemic stroke significantly improved functional outcome while reducing cerebral lesion and oedema volumes compared to vehicle-treated counterparts. Studies conducted with brain microvascular endothelial cells exposed to OGD ± R in the presence of Y-27632 revealed restoration of intercellular junctions and suppression of prooxidant NADPH oxidase activity as important factors in ROCK inhibition-mediated BBB protection. © 2014 International Society

  2. Angiocrine functions of organ-specific endothelial cells

    PubMed Central

    Rafii, Shahin; Butler, Jason M; Ding, Bi-Sen

    2016-01-01

    Preface Endothelial cells lining blood vessel capillaries are not just passive conduits for delivering blood. Tissue-specific endothelium establish specialized vascular niches that deploy specific sets of growth factors, known as angiocrine factors, which actively participate in inducing, specifying, patterning, and guiding organ regeneration and maintaining homeostasis and metabolism. Angiocrine factors upregulated in response to injury orchestrates self-renewal and differentiation of tissue-specific repopulating resident stem and progenitor cells into functional organs. Uncovering the precise mechanisms whereby physiological-levels of angiocrine factors are spatially and temporally produced, and distributed by organotypic endothelium to repopulating cells, will lay the foundation for driving organ repair without scarring. PMID:26791722

  3. A novel approach to the assessment of vascular endothelial function

    NASA Astrophysics Data System (ADS)

    Sathasivam, S.; Phababpha, S.; Sengmeuan, P.; Detchaporn, P.; Siddiqui, Z.; Kukongviriyapan, U.; Greenwald, S.

    2011-08-01

    Impaired endothelial function (EF) is associated with atherogenesis, and its quantitative assessment has prognostic value. Currently, methods based on assessing flow-mediated dilation (FMD) are technically difficult and expensive. We tested a novel way of assessing EF by measuring the time difference between pulses arriving at the middle fingers of each hand (f-fΔT), whilst FMD is induced in one arm. We compared f-fΔT with standard methods in healthy and diseased subjects. Our findings suggest that the proposed simple and inexpensive technique gives comparable results and has the potential to qualitatively assess EF in the clinical setting, although further work is required.

  4. Salvianolic acid B improves vascular endothelial function in diabetic rats with blood glucose fluctuations via suppression of endothelial cell apoptosis.

    PubMed

    Ren, Younan; Tao, Shanjun; Zheng, Shuguo; Zhao, Mengqiu; Zhu, Yuanmei; Yang, Jieren; Wu, Yuanjie

    2016-11-15

    Vascular endothelial cell injury is an initial event in atherosclerosis. Salvianolic acid B (Sal B), a main bioactive component in the root of Salvia miltiorrhiza, has vascular protective effect in diabetes, but the underlying mechanisms remain unclear. The present study investigated the effect of Sal B on vascular endothelial function in diabetic rats with blood glucose fluctuations and the possible mechanisms implicated. The results showed that diabetic rats developed marked endothelial dysfunction as exhibited by impaired acetylcholine induced vasodilation. Supplementation with Sal B resulted in an evident improvement of endothelial function. Phosphorylation (Ser 1177) of endothelial nitric oxide synthase (eNOS) was significantly restored in Sal B treated diabetic rats, accompanied by an evident recovery of NO metabolites. Sal B effectively reduced vascular endothelial cell apoptosis, with Bcl-2 protein up-regulated and Bax protein down-regulated markedly. Treatment with Sal B led to an evident amelioration of oxidative stress in diabetic rats as manifested by enhanced antioxidant capacity and decreased contents of malondialdehyde in aortas. Protein levels of NOX2 and NOX4, two main isoforms of NADPH oxidase known as the major source of reactive oxygen species in the vasculature, were markedly decreased in Sal B treated groups. In addition, treatment with Sal B led to an evident decrease of serum lipids. Taken together, this study indicates that Sal B is capable of improving endothelial function in diabetic rats with blood glucose fluctuations, of which the underlying mechanisms might be related to suppression of endothelial cell apoptosis and stimulation of eNOS phosphorylation (Ser 1177).

  5. The Drosophila blood-brain barrier: development and function of a glial endothelium

    PubMed Central

    Limmer, Stefanie; Weiler, Astrid; Volkenhoff, Anne; Babatz, Felix; Klämbt, Christian

    2014-01-01

    The efficacy of neuronal function requires a well-balanced extracellular ion homeostasis and a steady supply with nutrients and metabolites. Therefore, all organisms equipped with a complex nervous system developed a so-called blood-brain barrier, protecting it from an uncontrolled entry of solutes, metabolites or pathogens. In higher vertebrates, this diffusion barrier is established by polarized endothelial cells that form extensive tight junctions, whereas in lower vertebrates and invertebrates the blood-brain barrier is exclusively formed by glial cells. Here, we review the development and function of the glial blood-brain barrier of Drosophila melanogaster. In the Drosophila nervous system, at least seven morphologically distinct glial cell classes can be distinguished. Two of these glial classes form the blood-brain barrier. Perineurial glial cells participate in nutrient uptake and establish a first diffusion barrier. The subperineurial glial (SPG) cells form septate junctions, which block paracellular diffusion and thus seal the nervous system from the hemolymph. We summarize the molecular basis of septate junction formation and address the different transport systems expressed by the blood-brain barrier forming glial cells. PMID:25452710

  6. Ceramides and barrier function in healthy skin.

    PubMed

    Mutanu Jungersted, Jakob; Hellgren, Lars I; Høgh, Julie K; Drachmann, T; Jemec, Gregor B E; Agner, Tove

    2010-07-01

    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal water loss and with information on dry skin from a questionnaire including 16 people. No statistically significant differences were found between young and old skin for ceramide subgroups or ceramide/cholesterol ratios, and there was no statistically significant correlation between answers about dry skin and ceramide levels. Interestingly, a statistically significant higher ceramide/cholesterol ratio was found for men than for women (p = 0.02).

  7. Impact of pubertal development on endothelial function and arterial elasticity.

    PubMed

    Marlatt, Kara L; Steinberger, Julia; Dengel, Donald R; Sinaiko, Alan; Moran, Antoinette; Chow, Lisa S; Steffen, Lyn M; Zhou, Xia; Kelly, Aaron S

    2013-11-01

    Little is known about the relation of pubertal development on endothelial function and arterial elasticity in children and adolescents; therefore, we compared brachial artery flow-mediated dilation and carotid artery elasticity across Tanner (pubertal) stages in children and adolescents. Blood pressure, fasting lipids, glucose and insulin, body fat, insulin sensitivity adjusted for lean body mass, brachial flow-mediated dilation (percent dilation and area under the curve), endothelium-independent dilation (peak dilation and area under the curve), and carotid artery elasticity were evaluated across pubertal stages (Tanner I vs Tanner II-IV vs Tanner V) in 344 children and adolescents (184 males, 160 females; ages 6 to 21 years). One hundred twenty-four subjects (mean age 8.23 ± 0.15 years; 52 females) were Tanner stage I; 105 subjects (mean age 13.19 ± 0.17 years; 47 females) were Tanner stages II-IV; and 115 subjects (mean age 17.19 ± 0.16 years; 61 females) were Tanner stage V. There were no significant differences for any of the measures of vascular structure and function across pubertal stages. Results of the current study indicate that smooth-muscle and endothelial function, as well as carotid artery elasticity, do not differ throughout pubertal development and that accounting for pubertal stage when reporting vascular data in children and adolescents may be unnecessary. Copyright © 2013 Mosby, Inc. All rights reserved.

  8. Amyloid β induces adhesion of erythrocytes to endothelial cells and affects endothelial viability and functionality.

    PubMed

    Nakagawa, Kiyotaka; Kiko, Takehiro; Kuriwada, Satoko; Miyazawa, Taiki; Kimura, Fumiko; Miyazawa, Teruo

    2011-01-01

    It has been suggested that amyloid β-peptide (Aβ) might mediate the adhesion of erythrocytes to the endothelium which could disrupt the properties of endothelial cells. We provide evidence here that Aβ actually induced the binding of erythrocytes to endothelial cells and decreased endothelial viability, perhaps by the generation of oxidative and inflammatory stress. These changes are likely to contribute to the pathogenesis of Alzheimer's disease.

  9. Lifestyle modification and endothelial function in obese subjects.

    PubMed

    Hamdy, Osama

    2005-03-01

    The metabolic syndrome is a cluster of metabolic and vascular abnormalities that include central obesity, insulin resistance, hyperinsulinemia, glucose intolerance, hypertension, dyslipidemia, hypercoagulability and an increased risk of coronary and cerebral vascular disease. These metabolic and vascular abnormalities are the main cause of cardiovascular mortality in western societies. Endothelial dysfunction, an early step in the development of atherosclerosis, has been reported in obese nondiabetic individuals and in patients with Type 2 diabetes. It has also been observed in individuals at high risk for Type 2 diabetes, including those with impaired glucose tolerance and the normoglycemic first-degree relatives of Type 2 diabetic patients. Recent evidence points to adipocytes as a complex and active endocrine tissue whose secretory products, including free fatty acids and several cytokines (i.e., leptin, adiponectin, tissue necrosis factor-alpha, interleukin-6, and resistin) play a major role in the regulation of human metabolic and vascular biology. These adipocytokines have been claimed to be the missing link between insulin resistance and cardiovascular disease. Interventions designed to improve endothelial and/or adipose-tissue functions may reduce cardiovascular events in obese individuals with either the metabolic syndrome or Type 2 diabetes. Lifestyle modification in the form of caloric restriction and increased physical activity are the most common modalities used for treating those individuals at risk and is unanimously agreed to be the initial step in managing Type 2 diabetes. Several recent studies have demonstrated favorable impacts of lifestyle modifications in improving endothelial function and insulin sensitivity, in addition to altering serum levels of adipocytokines and possibly reducing cardiovascular events. This review discusses current knowledge of the role of lifestyle modifications in ameliorating cardiovascular risk in obese subjects with

  10. Regular blood donation improves endothelial function in adult males.

    PubMed

    Yücel, Hasan; Zorlu, Ali; Kaya, Hakkı; Yılmaz, Mehmet Birhan

    2016-03-01

    Endothelial dysfunction, secondary to systemic inflammation and oxidative stress, is known to play a major role in the development and progression of atherosclerosis. It is hypothesized that the lower incidence of coronary artery disease in the premenopausal period in females when compared with males is associated with regular menstrual blood loss. We investigated whether regular blood donation (BD) is associated with improved endothelial function in healthy adult males. Fifty young healthy male volunteers volunteers with a mean age of 30 ± 6 years without overt cardiovascular disease were enrolled to participate in serial consecutive BDs. Serum iron levels as oxidative stress parameters, flow-mediated dilatation (FMD) for endothelial function, 24-h mean diastolic blood pressure for peripheral vascular resistance identification, and high-sensitivity C-reactive protein (hs-CRP) levels as systemic inflammatory markers were evaluated before and after BD. This study used a prospective observational cohort design. Patients with cardiovascular and inflammatory diseases were excluded. BD was found to improve FMD steadily and significantly when compared with the baseline (mean ± SD: 9.9% ± 3.8%, 10.44% ± 3.9%, 10.65% ± 3.9%, and 10.75 ± 3.9%, respectively, p=0.15, p=0.02, p=0.006 as compared with the baseline). A steady decrease was identified in hs-CRP levels after serial BDs, although this decrease was not statistically significant in the all phases (2.96 ± 3.3 mg/L, 2.26 ± 1.5 mg/L, and 2.12 ± 1.5 mg/L, respectively, p=0.829, p=0.558). The 24-h mean diastolic blood pressures were significantly lower in the chronic phase (77 ± 9 mm Hg, 75 ± 7 mm Hg, and 72 ± 8 mm Hg, respectively, p=0.50, p=0.003), whereas there was no significant change in iron levels in the acute and chronic phases (66 ± 32 mg/dL, 72 ± 43 mg/dL, and 68 ± 33 mg/dL, respectively, p=1.000, p=1.000). The results of the study indicate that regular BD improves endothelial function.

  11. Blood-nerve barrier: distribution of anionic sites on the endothelial plasma membrane and basal lamina of dorsal root ganglia.

    PubMed

    Bush, M S; Reid, A R; Allt, G

    1991-09-01

    Previous investigations of the blood-nerve barrier have correlated the greater permeability of ganglionic endoneurial vessels, compared to those of nerve trunks, with the presence of fenestrations and open intercellular junctions. Recent studies have demonstrated reduced endothelial cell surface charge in blood vessels showing greater permeability. To determine the distribution of anionic sites on the plasma membranes and basal laminae of endothelial cells in dorsal root ganglia, cationic colloidal gold and cationic ferritin were used. Electron microscopy revealed the existence of endothelial microdomains with differing labelling densities. Labelling indicated that caveolar and fenestral diaphragms and basal laminae are highly anionic at physiological pH, luminal plasma membranes and endothelial processes are moderately charged and abluminal plasma membranes are weakly anionic. Tracers did not occur in caveolae or cytoplasmic vesicles. In vitro tracer experiments at pH values of 7.3, 5.0, 3.5 and 2.0 indicated that the anionic charge on the various endothelial domains was contributed by chemical groups with differing pKa values. In summary, the labelling of ganglionic and sciatic nerve vessels was similar except for the heavy labelling of diaphragms in a minority of endoneurial vessels in ganglia. This difference is likely to account in part for the greater permeability of ganglionic endoneurial vessels. The results are discussed with regard to the blood-nerve and -brain barriers and vascular permeability in other tissues and a comparison made between the ultrastructure and anionic microdomains of epi-, peri- and endoneurial vessels of dorsal root ganglia and sciatic nerves.

  12. Lung endothelial barrier protection by iloprost in the two-hit models of VILI involves inhibition of Rho signaling

    PubMed Central

    Birukova, Anna A.; Fu, Panfeng; Xing, Junjie; Cokic, Ivan; Birukov, Konstantin G.

    2010-01-01

    Mechanical ventilation at high tidal volume may cause pulmonary capillary leakage and acute lung inflammation culminating in ventilator-induced lung injury. Iloprost is a stable synthetic analogue of prostaglandin I2 used for treatment of pulmonary hypertension, which also showed endothelium-dependent anti-edemagenic effects in the models of lung injury. To test the hypothesis that iloprost may attenuate lung inflammation and lung endothelial barrier disruption caused by pathologic lung distension and coagulation system component thrombin, we used cell and animal two-hit models of ventilator-induced lung injury. Mice received triple injection of iloprost (2 μg/kg, intravenous instillation) at 0, 40 and 80 min after onset of high tidal volume (HTV) mechanical ventilation (30 ml/kg, 4 hrs) combined with administration of thrombin receptor activating peptide 6 (TRAP6, 3 × 10−7 mol/mouse, intratracheal instillation). After 4 hrs of ventilation, bronchoalveolar lavage (BAL), histological analysis, and measurements of Evans blue accumulation in the lung tissue lung were performed. Effects of iloprost on endothelial barrier dysfunction were further assessed in pulmonary endothelial cells (EC) exposed to thrombin and pathologic (18%) cyclic stretch. Combination of HTV and TRAP6 enhanced accumulation of neutrophils in BAL fluid and lung parenchyma, increased BAL protein content and endothelial permeability judged by Evans blue extravasation in the lung tissue. These effects were markedly attenuated by iloprost. Application of 18% cyclic stretch to pulmonary EC enhanced thrombin-induced EC paracellular gap formation and Rho-GTPase-mediated phosphorylation of regulatory myosin light chains and myosin phosphatase. Iloprost markedly inhibited Rho-kinase mediated site-specific phosphorylation of myosin phosphatase, and prevented cyclic stretch- and thrombin-induced endothelial monolayer disruption. This study characterizes for the first time the protective effects of

  13. Organic nitrates differentially modulate circulating endothelial progenitor cells and endothelial function in patients with symptomatic coronary artery disease.

    PubMed

    Thum, Thomas; Wiebking, Volker; Ertl, Georg; Bauersachs, Johann

    2011-08-15

    Symptomatic coronary artery disease (CAD) is usually treated with organic nitrates. Endothelial progenitor cells (EPCs) are a circulating cell population participating in vascular homeostasis in a nitric oxide-dependent manner. We investigated the effects of the nitric oxide donors isosorbide dinitrate (ISDN) and pentaerythritol tetranitrate (PETN) on EPC and endothelial function in patients with symptomatic CAD. We randomized 36 patients with angiographically proven CAD to treatment with either ISDN (40 mg retarded release orally two times per day; n = 18) or PETN (80 mg orally two times per day; n = 18) for 14 days (clinical trial number: NCT01030367). PETN treatment substantially increased numbers of circulating CD34(+)/KDR(+) EPCs (p = 0.02), whereas no effects were observed in patients treated with ISDN. EPC function assessed by formation of endothelial colonies was enhanced by twofold (p = 0.04) in patients treated with PETN. No changes were observed after ISDN treatment. Endothelial function, assessed by peripheral arterial tonometry, remained unchanged during PETN treatment, but was significantly impaired in patients treated with ISDN. Treatment of symptomatic CAD patients with PETN for 14 days significantly increased levels of circulating EPC and improved markers for EPC function, whereas ISDN was without effects on EPCs and worsened endothelial function.

  14. Assessment of endothelial and neurovascular function in human skin microcirculation.

    PubMed

    Roustit, Matthieu; Cracowski, Jean-Luc

    2013-07-01

    Peripheral microvascular dysfunction has been described in many physiological and pathological conditions. Owing to its accessibility, the cutaneous microcirculation provides a unique index of microvascular function. Skin microvascular function has therefore been proposed as a prognostic marker or for evaluating the effect of drugs on the microcirculation. Various reactivity tests, coupled with techniques measuring skin blood flux, are used to non-invasively explore both endothelial and neurovascular microvascular functioning in humans. We review the advantages and limitations of the main reactivity tests, including post-occlusive reactive hyperemia, local thermal hyperemia, pressure-induced vasodilation, and iontophoresis of vasodilators, combined with measurement techniques such as laser Doppler and laser speckle contrast imaging. Recent advances in our comprehension of the physiological pathways underlying these reactivity tests, as well as technological developments in microcirculation imaging, have provided reliable and reproducible tools for studying the microcirculation.

  15. Alveolar macrophage inducible nitric oxide synthase-dependent pulmonary microvascular endothelial cell septic barrier dysfunction.

    PubMed

    Farley, K S; Wang, L F; Law, C; Mehta, S

    2008-11-01

    Inducible nitric oxide (NO) synthase (iNOS) from neutrophils and alveolar macrophages (AM) contributes to the pathophysiology of murine septic acute lung injury (ALI). It is not known if AM iNOS has a direct effect on septic pulmonary microvascular endothelial cell (PMVEC) permeability. We hypothesized that AM iNOS mediates PMVEC permeability in vitro under septic conditions through NO and peroxynitrite. 100,000 confluent PMVEC on cell-culture inserts were co-incubated with iNOS+/+ vs. iNOS-/- AM, in various ratios of AM to PMVEC. PMVEC injury was assessed by trans-PMVEC Evans Blue-labelled albumin flux in the presence or absence of cytomix (equimolar TNF-alpha, IL-1beta and IFN-gamma). Cytomix stimulation dose-dependently increased trans-PMVEC EB-albumin flux, which was exaggerated (1.4+/-0.1% vs. 0.4+/-0.1% in unstimulated PMVEC, p<0.05) in the presence of iNOS+/+, but not iNOS-/-, AM in the upper compartment. Similarly, iNOS+/+, but not iNOS-/-, AM in the lower compartment also enhanced septic trans-PMVEC albumin leak. The mechanism of iNOS-dependent septic PMVEC permeability was pursued through pharmacologic studies with inhibitors of NOS, and scavengers of NO, superoxide, and peroxynitrite, and treatment of PMVEC with the NO donor, DETA-NONOate. Septic iNOS+/+ AM-dependent trans-PMVEC albumin leak was significantly attenuated by pharmacologic iNOS inhibition (L-NAME and 1400W), and scavenging of either NO (oxyhemoglobin), superoxide (PEG-SOD), or peroxynitrite (FeTPPS). Exogenous NO (DETA-NONOate) had no effect on PMVEC permeability. These data are consistent with a direct role of AM iNOS in septic PMVEC barrier dysfunction, which is likely mediated, in part, through peroxynitrite.

  16. Shiftwork and Decline in Endothelial Function Among Police Officers

    PubMed Central

    Charles, Luenda E.; Zhao, Songzhu; Fekedulegn, Desta; Violanti, John M.; Andrew, Michael E.; Burchfiel, Cecil M.

    2016-01-01

    Background Our objective was to assess the influence of shiftwork on change in endothelial function. Methods This longitudinal study was conducted in 188 police officers (78.2% men). Shiftwork status (day, afternoon, night) was assessed objectively using daily Buffalo, NY payroll work history records. Brachial artery flow-mediated dilation (FMD) was assessed using ultrasound. Mean change in FMD% between 2004–2009 and 2010–2015 was compared across shiftwork using analysis of variance/covariance. Results Overall, mean FMD% decreased from 5.74 ± 2.83 to 3.88 ± 2.11 over an average of 7 years among all officers; P < 0.0001. Effect modification by gender was significant. Among men (but not women), those who worked day shifts had a smaller mean (±SE) decrease in FMD% (−0.89 ± 0.35) compared with those who worked the afternoon (−2.69 ± 0.39; P = 0.001) or night shifts (−2.31 ± 0.45; P = 0.020) after risk factor adjustment. Conclusions Larger declines in endothelial function were observed among men who worked afternoon or night shifts. Further investigation is warranted. Am. J. Ind. Med. Published 2016. This article is a U.S. Government work and is in the public domain in the USA PMID:27245641

  17. Brief Exposure to Secondhand Smoke Reversibly Impairs Endothelial Vasodilatory Function

    PubMed Central

    2014-01-01

    Introduction: We sought to determine the effects of brief exposures to low concentrations of tobacco secondhand smoke (SHS) on arterial flow-mediated dilation (FMD, a nitric oxide-dependent measure of vascular endothelial function), in a controlled animal model never before exposed to smoke. In humans, SHS exposure for 30min impairs FMD. It is important to gain a better understanding of the acute effects of exposure to SHS at low concentrations and for brief periods of time. Methods: We measured changes in FMD in rats exposed to a range of real-world levels of SHS for durations of 30min, 10min, 1min, and 4 breaths (roughly 15 s). Results: We observed a dose-response relationship between SHS particle concentration over 30min and post-exposure impairment of FMD, which was linear through the range typically encountered in smoky restaurants and then saturated at higher concentrations. One min of exposure to SHS at moderate concentrations was sufficient to impair FMD. Conclusions: Brief SHS exposure at real-world levels reversibly impairs FMD. Even 1min of SHS exposure can cause reduction of endothelial function. PMID:24302638

  18. Endothelial Function Is Associated with White Matter Microstructure and Executive Function in Older Adults

    PubMed Central

    Johnson, Nathan F.; Gold, Brian T.; Brown, Christopher A.; Anggelis, Emily F.; Bailey, Alison L.; Clasey, Jody L.; Powell, David K.

    2017-01-01

    Age-related declines in endothelial function can lead to cognitive decline. However, little is known about the relationships between endothelial function and specific neurocognitive functions. This study explored the relationship between measures of endothelial function (reactive hyperemia index; RHI), white matter (WM) health (fractional anisotropy, FA, and WM hyperintensity volume, WMH), and executive function (Trail Making Test (TMT); Trail B − Trail A). Participants were 36 older adults between the ages of 59 and 69 (mean age = 63.89 years, SD = 2.94). WMH volume showed no relationship with RHI or executive function. However, there was a positive relationship between RHI and FA in the genu and body of the corpus callosum. In addition, higher RHI and FA were each associated with better executive task performance. Tractography was used to localize the WM tracts associated with RHI to specific portions of cortex. Results indicated that the RHI-FA relationship observed in the corpus callosum primarily involved tracts interconnecting frontal regions, including the superior frontal gyrus (SFG) and frontopolar cortex, linked with executive function. These findings suggest that superior endothelial function may help to attenuate age-related declines in WM microstructure in portions of the corpus callosum that interconnect prefrontal brain regions involved in executive function. PMID:28824417

  19. Endothelial Function Is Associated with White Matter Microstructure and Executive Function in Older Adults.

    PubMed

    Johnson, Nathan F; Gold, Brian T; Brown, Christopher A; Anggelis, Emily F; Bailey, Alison L; Clasey, Jody L; Powell, David K

    2017-01-01

    Age-related declines in endothelial function can lead to cognitive decline. However, little is known about the relationships between endothelial function and specific neurocognitive functions. This study explored the relationship between measures of endothelial function (reactive hyperemia index; RHI), white matter (WM) health (fractional anisotropy, FA, and WM hyperintensity volume, WMH), and executive function (Trail Making Test (TMT); Trail B - Trail A). Participants were 36 older adults between the ages of 59 and 69 (mean age = 63.89 years, SD = 2.94). WMH volume showed no relationship with RHI or executive function. However, there was a positive relationship between RHI and FA in the genu and body of the corpus callosum. In addition, higher RHI and FA were each associated with better executive task performance. Tractography was used to localize the WM tracts associated with RHI to specific portions of cortex. Results indicated that the RHI-FA relationship observed in the corpus callosum primarily involved tracts interconnecting frontal regions, including the superior frontal gyrus (SFG) and frontopolar cortex, linked with executive function. These findings suggest that superior endothelial function may help to attenuate age-related declines in WM microstructure in portions of the corpus callosum that interconnect prefrontal brain regions involved in executive function.

  20. Oxidative and pro-inflammatory impact of regular and denicotinized cigarettes on blood brain barrier endothelial cells: is smoking reduced or nicotine-free products really safe?

    PubMed

    Naik, Pooja; Fofaria, Neel; Prasad, Shikha; Sajja, Ravi K; Weksler, Babette; Couraud, Pierre-Olivier; Romero, Ignacio A; Cucullo, Luca

    2014-04-23

    Both active and passive tobacco smoke (TS) potentially impair the vascular endothelial function in a causative and dose-dependent manner, largely related to the content of reactive oxygen species (ROS), nicotine, and pro-inflammatory activity. Together these factors can compromise the restrictive properties of the blood-brain barrier (BBB) and trigger the pathogenesis/progression of several neurological disorders including silent cerebral infarction, stroke, multiple sclerosis and Alzheimer's disease. Based on these premises, we analyzed and assessed the toxic impact of smoke extract from a range of tobacco products (with varying levels of nicotine) on brain microvascular endothelial cell line (hCMEC/D3), a well characterized human BBB model. Initial profiling of TS showed a significant release of reactive oxygen (ROS) and reactive nitrogen species (RNS) in full flavor, nicotine-free (NF, "reduced-exposure" brand) and ultralow nicotine products. This release correlated with increased oxidative cell damage. In parallel, membrane expression of endothelial tight junction proteins ZO-1 and occludin were significantly down-regulated suggesting the impairment of barrier function. Expression of VE-cadherin and claudin-5 were also increased by the ultralow or nicotine free tobacco smoke extract. TS extract from these cigarettes also induced an inflammatory response in BBB ECs as demonstrated by increased IL-6 and MMP-2 levels and up-regulation of vascular adhesion molecules, such as VCAM-1 and PECAM-1. In summary, our results indicate that NF and ultralow nicotine cigarettes are potentially more harmful to the BBB endothelium than regular tobacco products. In addition, this study demonstrates that the TS-induced toxicity at BBB ECs is strongly correlated to the TAR and NO levels in the cigarettes rather than the nicotine content.

  1. Low-Dose Lithium Stabilizes Human Endothelial Barrier by Decreasing MLC Phosphorylation and Universally Augments Cholinergic Vasorelaxation Capacity in a Direct Manner

    PubMed Central

    Bosche, Bert; Molcanyi, Marek; Rej, Soham; Doeppner, Thorsten R.; Obermann, Mark; Müller, Daniel J.; Das, Anupam; Hescheler, Jürgen; Macdonald, R. Loch; Noll, Thomas; Härtel, Frauke V.

    2016-01-01

    Lithium at serum concentrations up to 1 mmol/L has been used in patients suffering from bipolar disorder for decades and has recently been shown to reduce the risk for ischemic stroke in these patients. The risk for stroke and thromboembolism depend not only on cerebral but also on general endothelial function and health; the entire endothelium as an organ is therefore pathophysiologically relevant. Regardless, the knowledge about the direct impact of lithium on endothelial function remains poor. We conducted an experimental study using lithium as pharmacologic pretreatment for murine, porcine and human vascular endothelium. We predominantly investigated endothelial vasorelaxation capacities in addition to human basal and dynamic (thrombin-/PAR-1 receptor agonist-impaired) barrier functioning including myosin light chain (MLC) phosphorylation (MLC-P). Low-dose therapeutic lithium concentrations (0.4 mmol/L) significantly augment the cholinergic endothelium-dependent vasorelaxation capacities of cerebral and thoracic arteries, independently of central and autonomic nerve system influences. Similar concentrations of lithium (0.2–0.4 mmol/L) significantly stabilized the dynamic thrombin-induced and PAR-1 receptor agonist-induced permeability of human endothelium, while even the basal permeability appeared to be stabilized. The lithium-attenuated dynamic permeability was mediated by a reduced endothelial MLC-P known to be followed by a lessening of endothelial cell contraction and paracellular gap formation. The well-known lithium-associated inhibition of inositol monophosphatase/glycogen synthase kinase-3-β signaling-pathways involving intracellular calcium concentrations in neurons seems to similarly occur in endothelial cells, too, but with different down-stream effects such as MLC-P reduction. This is the first study discovering low-dose lithium as a drug directly stabilizing human endothelium and ubiquitously augmenting cholinergic endothelium

  2. Endothelial β-Catenin Signaling Is Required for Maintaining Adult Blood-Brain Barrier Integrity and CNS Homeostasis

    PubMed Central

    Tran, Khiem A.; Zhang, Xianming; Predescu, Dan; Huang, Xiaojia; Machado, Roberto F.; Göthert, Joachim R.; Malik, Asrar B.; Valyi-Nagy, Tibor; Zhao, You-Yang

    2015-01-01

    Background The blood-brain barrier (BBB) formed by brain endothelial cells (ECs) interconnected by tight junctions (TJs) is essential for the homeostasis of the central nervous system (CNS). Although studies have shown the importance of various signaling molecules in BBB formation during development, little is known about the molecular basis regulating the integrity of the adult BBB. Methods and Results Using a mouse model with tamoxifen-inducible EC-restricted disruption of ctnnb1 (iCKO), here we show that endothelial β-catenin signaling is essential for maintaining BBB integrity and CNS homeostasis in adult. The iCKO mice developed severe seizures accompanied by neuronal injury, multiple brain petechial hemorrhages, and CNS inflammation, and all died postictal. Disruption of endothelial β-catenin induced BBB breakdown and downregulation of specific TJ proteins Claudin-1 and -3 in adult brain ECs. The clinical relevance of the data is indicated by the observation of decreased expression of Claudin-1 and nuclear β-catenin in brain ECs of hemorrhagic lesions of hemorrhagic stroke patients. Conclusion These results demonstrate the prerequisite role of endothelial β-catenin in maintaining the integrity of adult BBB. The results suggest that BBB dysfunction secondary to defective β-catenin transcription activity is a key pathogenic factor in hemorrhagic stroke, seizure activity and CNS inflammation. PMID:26538583

  3. Permeability of Endothelial and Astrocyte Cocultures: In Vitro Blood–Brain Barrier Models for Drug Delivery Studies

    PubMed Central

    Li, Guanglei; Simon, Melissa J.; Cancel, Limary M.; Shi, Zhong-Dong; Ji, Xinying; Tarbell, John M.; Morrison, Barclay; Fu, Bingmei M.

    2014-01-01

    The blood–brain barrier (BBB) is a major obstacle for drug delivery to the brain. To seek for in vitro BBB models that are more accessible than animals for investigating drug transport across the BBB, we compared four in vitro cultured cell models: endothelial monoculture (bEnd3 cell line), coculture of bEnd3 and primary rat astrocytes (coculture), coculture with collagen type I and IV mixture, and coculture with Matrigel. The expression of the BBB tight junction proteins in these in vitro models was assessed using RT-PCR and immunofluorescence. We also quantified the hydraulic conductivity (Lp), transendothelial electrical resistance (TER) and diffusive solute permeability (P) of these models to three solutes: TAMRA, Dextran 10K and Dextran 70K. Our results show that Lp and P of the endothelial monoculture and coculture models are not different from each other. Compared with in vivo permeability data from rat pial microvessels, P of the endothelial monoculture and coculture models are not significantly different from in vivo data for Dextran 70K, but they are 2–4 times higher for TAMRA and Dextran 10K. This suggests that the endothelial monoculture and all of the coculture models are fairly good models for studying the transport of relatively large solutes across the BBB. PMID:20361260

  4. Permeability of endothelial and astrocyte cocultures: in vitro blood-brain barrier models for drug delivery studies.

    PubMed

    Li, Guanglei; Simon, Melissa J; Cancel, Limary M; Shi, Zhong-Dong; Ji, Xinying; Tarbell, John M; Morrison, Barclay; Fu, Bingmei M

    2010-08-01

    The blood-brain barrier (BBB) is a major obstacle for drug delivery to the brain. To seek for in vitro BBB models that are more accessible than animals for investigating drug transport across the BBB, we compared four in vitro cultured cell models: endothelial monoculture (bEnd3 cell line), coculture of bEnd3 and primary rat astrocytes (coculture), coculture with collagen type I and IV mixture, and coculture with Matrigel. The expression of the BBB tight junction proteins in these in vitro models was assessed using RT-PCR and immunofluorescence. We also quantified the hydraulic conductivity (L (p)), transendothelial electrical resistance (TER) and diffusive solute permeability (P) of these models to three solutes: TAMRA, Dextran 10K and Dextran 70K. Our results show that L (p) and P of the endothelial monoculture and coculture models are not different from each other. Compared with in vivo permeability data from rat pial microvessels, P of the endothelial monoculture and coculture models are not significantly different from in vivo data for Dextran 70K, but they are 2-4 times higher for TAMRA and Dextran 10K. This suggests that the endothelial monoculture and all of the coculture models are fairly good models for studying the transport of relatively large solutes across the BBB.

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

    PubMed Central

    Kassan, M.; Vikram, A.; Kim, Y. R.; Li, Q.; Kassan, A.; Patel, H. H.; Kumar, S.; Gabani, M.; Liu, J.; Jacobs, J. S.; Irani, K.

    2017-01-01

    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. PMID:28181559

  6. Multidrug-resistance gene (P-glycoprotein) is expressed by endothelial cells at blood-brain barrier sites

    SciTech Connect

    Cordon-Cardo, C.; O'Brien, J.P.; Casals, D.; Biedler, J.L.; Melamed, M.R.; Bertino, J.R. ); Rittman-Grauer, L. )

    1989-01-01

    Endothelial cells of human capillary blood vessels at the blood-brain and other blood-tissue barrier sites express P-glycoprotein as detected by mouse monoclonal antibodies against the human multidrug-resistance gene product. This pattern of endothelial cell expression may indicate a physiological role for P-glycoprotein in regulating the entry of certain molecules into the central nervous system and other anatomic compartments, such as the testes. These tissues, which limit the access of systemic drugs, are known pharmacologic sanctuaries for metastatic cancer. P-glycoprotein expression in capillary endothelium of brain and testes and not other tissues (i.e., kidney and placenta) may in part explain this phenomenon and could have important implications in cancer chemotherapy.

  7. Uptake Mechanism of ApoE-Modified Nanoparticles on Brain Capillary Endothelial Cells as a Blood-Brain Barrier Model

    PubMed Central

    Wagner, Sylvia; Zensi, Anja; Wien, Sascha L.; Tschickardt, Sabrina E.; Maier, Wladislaw; Vogel, Tikva; Worek, Franz; Pietrzik, Claus U.; Kreuter, Jörg; von Briesen, Hagen

    2012-01-01

    Background The blood-brain barrier (BBB) represents an insurmountable obstacle for most drugs thus obstructing an effective treatment of many brain diseases. One solution for overcoming this barrier is a transport by binding of these drugs to surface-modified nanoparticles. Especially apolipoprotein E (ApoE) appears to play a major role in the nanoparticle-mediated drug transport across the BBB. However, at present the underlying mechanism is incompletely understood. Methodology/Principal Findings In this study, the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells was investigated to differentiate between active and passive uptake mechanism by flow cytometry and confocal laser scanning microscopy. Furthermore, different in vitro co-incubation experiments were performed with competing ligands of the respective receptor. Conclusions/Significance This study confirms an active endocytotic uptake mechanism and shows the involvement of low density lipoprotein receptor family members, notably the low density lipoprotein receptor related protein, on the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells. This knowledge of the uptake mechanism of ApoE-modified nanoparticles enables future developments to rationally create very specific and effective carriers to overcome the blood-brain barrier. PMID:22396775

  8. VE-cadherin trans-interactions modulate Rac activation and enhancement of lung endothelial barrier by iloprost.

    PubMed

    Birukova, Anna A; Tian, Yufeng; Dubrovskyi, Oleksii; Zebda, Noureddine; Sarich, Nicolene; Tian, Xinyong; Wang, Yingxiao; Birukov, Konstantin G

    2012-10-01

    Small GTPase Rac is important regulator of endothelial cell (EC) barrier enhancement by prostacyclin characterized by increased peripheral actin cytoskeleton and increased interactions between VE-cadherin and other adherens junction (AJ) proteins. This study utilized complementary approaches including siRNA knockdown, culturing in Ca(2+) -free medium, and VE-cadherin blocking antibody to alter VE-cadherin extracellular interactions to investigate the role of VE-cadherin outside-in signaling in modulation of Rac activation and EC barrier regulation by prostacyclin analog iloprost. Spatial analysis of Rac activation in pulmonary EC by FRET revealed additional spike in iloprost-induced Rac activity at the sites of newly formed cell-cell junctions. In contrast, disruption of VE-cadherin extracellular trans-interactions suppressed iloprost-activated Rac signaling and attenuated EC barrier enhancement and cytoskeletal remodeling. These inhibitory effects were associated with decreased membrane accumulation and activation of Rac-specific guanine nucleotide exchange factors (GEFs) Tiam1 and Vav2. Conversely, plating of pulmonary EC on surfaces coated with extracellular VE-cadherin domain further promoted iloprost-induced Rac signaling. In the model of thrombin-induced EC barrier recovery, blocking of VE-cadherin trans-interactions attenuated activation of Rac pathway during recovery phase and delayed suppression of Rho signaling and restoration of EC barrier properties. These results suggest that VE-cadherin outside-in signaling controls locally Rac activity stimulated by barrier protective agonists. This control is essential for maximal EC barrier enhancement and accelerated barrier recovery.

  9. VE-cadherin trans-interactions modulate Rac activation and enhancement of lung endothelial barrier by iloprost

    PubMed Central

    Birukova, Anna A.; Tian, Yufeng; Dubrovskyi, Oleksii; Zebda, Noureddine; Sarich, Nicolene; Tian, Xinyong; Wang, Yingxiao; Birukov, Konstantin G.

    2012-01-01

    Small GTPase Rac is important regulator of endothelial cell (EC) barrier enhancement by prostacyclin characterized by increased peripheral actin cytoskeleton and increased interactions between VE-cadherin and other adherens junction (AJ) proteins. This study utilized complementary approaches including siRNA knockdown, culturing in Ca2+-free medium, and VE-cadherin blocking antibody to alter VE-cadherin extracellular interactions to investigate the role of VE-cadherin outside-in signaling in modulation of Rac activation and EC barrier regulation by prostacyclin analog iloprost. Spatial analysis of Rac activation in pulmonary EC by FRET revealed additional spike in iloprost-induced Rac activity at the sites of newly formed cell-cell junctions. In contrast, disruption of VE-cadherin extracellular trans-interactions suppressed iloprost-activated Rac signaling and attenuated EC barrier enhancement and cytoskeletal remodeling. These inhibitory effects were associated with decreased membrane accumulation and activation of Rac-specific guanine nucleotide exchange factors (GEF) Tiam1 and Vav2. Conversely, plating of pulmonary EC on surfaces coated with extracellular VE-cadherin domain further promoted iloprost-induced Rac signaling. In the model of thrombin-induced EC barrier recovery, blocking of VE-cadherin trans-interactions attenuated activation of Rac pathway during recovery phase and delayed suppression of Rho signaling and restoration of EC barrier properties. These results suggest that VE-cadherin outside-in signaling controls locally Rac activity stimulated by barrier protective agonists. This control is essential for maximal EC barrier enhancement and accelerated barrier recovery. PMID:22213015

  10. CD34 expression modulates tube-forming capacity and barrier properties of peripheral blood-derived endothelial colony-forming cells (ECFCs).

    PubMed

    Tasev, Dimitar; Konijnenberg, Lara S F; Amado-Azevedo, Joana; van Wijhe, Michiel H; Koolwijk, Pieter; van Hinsbergh, Victor W M

    2016-07-01

    Endothelial colony-forming cells (ECFC) are grown from circulating CD34(+) progenitors present in adult peripheral blood, but during in vitro expansion part of the cells lose CD34. To evaluate whether the regulation of CD34 characterizes the angiogenic phenotypical features of PB-ECFCs, we investigated the properties of CD34(+) and CD34(-) ECFCs with respect to their ability to form capillary-like tubes in 3D fibrin matrices, tip-cell gene expression, and barrier integrity. Selection of CD34(+) and CD34(-) ECFCs from subcultured ECFCs was accomplished by magnetic sorting (FACS: CD34(+): 95 % pos; CD34(-): 99 % neg). Both fractions proliferated at same rate, while CD34(+) ECFCs exhibited higher tube-forming capacity and tip-cell gene expression than CD3(4-) cells. However, during cell culture CD34(-) cells re-expressed CD34. Cell-seeding density, cell-cell contact formation, and serum supplements modulated CD34 expression. CD34 expression in ECFCs was strongly suppressed by newborn calf serum. Stimulation with FGF-2, VEGF, or HGF prepared in medium supplemented with 3 % albumin did not change CD34 mRNA or surface expression. Silencing of CD34 with siRNA resulted in strengthening of cell-cell contacts and increased barrier function of ECFC monolayers as measured by ECIS. Furthermore, CD34 siRNA reduced tube formation by ECFC, but did not affect tip-cell gene expression. These findings demonstrate that CD34(+) and CD34(-) cells are different phenotypes of similar cells and that CD34 (1) can be regulated in ECFC; (2) is positively involved in capillary-like sprout formation; (3) is associated but not causally related to tip-cell gene expression; and (4) can affect endothelial barrier function.

  11. Effects of physical training on endothelial function and limb blood flow in type 2 diabetes.

    PubMed

    Sonne, Mette Paulli; Scheede-Bergdahl, Celena; Olsen, David Benee; Højbjerre, Lise; Alibegovic, Amra; Nielsen, Ninna Bo; Stallknecht, Bente; Helge, Jørn Wulff; Vaag, Allan; Dela, Flemming

    2007-10-01

    The term "endothelial dysfunction" refers to the inability or attenuated effect of the endothelial cells in participating in the relaxation of the adjacent smooth muscle, thus causing less vasodilation. Although endothelial dysfunction is often seen in patients with type 2 diabetes, it does not necessarily follow that insulin resistance and (or) hyperglycemia is causing the inability to respond properly to vasodilatory stimuli. Rather, this could be related to the impact of concomitant cardiovascular risk factors that are almost invariably present in patients with type 2 diabetes. The impact of physical training - or the opposite, inactivity - on endothelial function is not fully elucidated. Some studies have shown positive effects of physical training, whereas others have not. In general, physical training can improve endothelial function when this is impaired. However, physical training does not seem to have any effect on endothelial function when this is normal.

  12. Endothelial S100A1 modulates vascular function via nitric oxide.

    PubMed

    Pleger, Sven T; Harris, David M; Shan, Changguang; Vinge, Leif E; Chuprun, J Kurt; Berzins, Brett; Pleger, Wiebke; Druckman, Charles; Völkers, Mirko; Heierhorst, Jörg; Øie, Erik; Remppis, Andrew; Katus, Hugo A; Scalia, Rosario; Eckhart, Andrea D; Koch, Walter J; Most, Patrick

    2008-04-11

    S100A1, a Ca(2+)-binding protein of the EF-hand type, is known to modulate sarcoplasmic reticulum Ca(2+) handling in skeletal muscle and cardiomyocytes. Recently, S100A1 has been shown to be expressed in endothelial cells (ECs). Because intracellular Ca(2+) ([Ca(2+)](i)) transients can be involved in important EC functions and endothelial NO synthase activity, we sought to investigate the impact of endothelial S100A1 on the regulation of endothelial and vascular function. Thoracic aortas from S100A1 knockout mice (SKO) showed significantly reduced relaxation in response to acetylcholine compared with wild-type vessels, whereas direct vessel relaxation using sodium nitroprusside was unaltered. Endothelial dysfunction attributable to the lack of S100A1 expression could also be demonstrated in vivo and translated into hypertension of SKO. Mechanistically, both basal and acetylcholine-induced endothelial NO release of SKO aortas was significantly reduced compared with wild type. Impaired endothelial NO production in SKO could be attributed, at least in part, to diminished agonist-induced [Ca(2+)](i) transients in ECs. Consistently, silencing endothelial S100A1 expression in wild type also reduced [Ca(2+)](i) and NO generation. Moreover, S100A1 overexpression in ECs further increased NO generation that was blocked by the inositol-1,4,5-triphosphate receptor blocker 2-aminoethoxydiphenylborate. Finally, cardiac endothelial S100A1 expression was shown to be downregulated in heart failure in vivo. Collectively, endothelial S100A1 critically modulates vascular function because lack of S100A1 expression leads to decreased [Ca(2+)](i) and endothelial NO release, which contributes, at least partially, to impaired endothelium-dependent vascular relaxation and hypertension in SKO mice. Targeting endothelial S100A1 expression may, therefore, be a novel therapeutic means to improve endothelial function in vascular disease or heart failure.

  13. VEGF-A165 potently induces human blood-nerve barrier endothelial cell proliferation, angiogenesis and wound healing in vitro

    PubMed Central

    Reddy, Chetan Lakshmana; Yosef, Nejla; Ubogu, Eroboghene E.

    2013-01-01

    Several mitogens such as vascular endothelial growth factor (VEGF) have been implicated in mammalian vascular proliferation and repair. However, the molecular mediators of human blood-nerve barrier (BNB) development and specialization are unknown. Primary human endoneurial endothelial cells (pHEndECs) were expanded in vitro and specific mitogen receptors detected by western blot. pHEndECs were cultured with basal medium containing different mitogen concentrations with or without heparin. Non-radioactive cell proliferation, Matrigel™-induced angiogenesis and sterile micropipette injury wound healing assays were performed. Proliferation rates, number and total length of induced microvessels and rate of endothelial cell monolayer wound healing were determined and compared to basal conditions. VEGF-A165 in the presence of heparin, was the most potent inducer of pHEndEC proliferation, angiogenesis and wound healing in vitro. 1.31 nM VEGF-A165 induced ~110% increase in cell proliferation relative to basal conditions (~51% without heparin). 2.62 pM VEGF-A165 induced a 3-fold increase in mean number of microvessels and 3.9-fold increase in total capillary length/field relative to basal conditions. In addition, 0.26 nM VEGF-A165 induced ~1.3-fold increased average rate of endothelial wound healing 4–18 hours after endothelial monolayer injury, mediated by increased cell migration. VEGF-A165 was the only mitogen capable of complete wound closure, occurring within 30 hours following injury via increased cell proliferation. This study demonstrates that VEGF-A165, in the presence of heparin, is a potent inducer of pHEndEC proliferation, angiogenesis and wound healing in vitro. VEGF-A165 may be an important mitogen necessary for human BNB development and recovery in response to peripheral nerve injury. PMID:23712256

  14. Effect of high potassium diet on endothelial function.

    PubMed

    Blanch, N; Clifton, P M; Petersen, K S; Willoughby, S R; Keogh, J B

    2014-09-01

    Increased potassium intake is related to reduced blood pressure (BP) and reduced stroke rate. The effect of increased dietary potassium on endothelial function remains unknown. The aim was to determine the effect of increased dietary potassium from fruit and vegetables on endothelial function. Thirty five healthy men and women (age 32 ± 12 y) successfully completed a randomised cross-over study of 2 × 6 day diets either high or low in potassium. Flow mediated dilatation (FMD), BP, pulse wave velocity (PWV), augmentation index (AI) and a fasting blood sample for analysis of Intercellular Adhesion Molecule-1 (ICAM-1), E-selectin, asymmetric dimethylarginine (ADMA) and endothelin-1 were taken on completion of each intervention. Dietary change was achieved by including bananas and potatoes in the high potassium and apples and rice/pasta in the low potassium diet. Dietary adherence was assessed using 6 day weighed food diaries and a 24 h urine sample. The difference in potassium excretion between the two diets was 48 ± 32 mmol/d (P = 0.000). Fasting FMD was significantly improved by 0.6% ± 1.5% following the high compared to the low potassium diet (P = 0.03). There were no significant differences in BP, PWV, AI, ICAM-1, ADMA or endothelin-1 between the interventions. There was a significant reduction in E-selectin following the high (Median = 5.96 ng/ml) vs the low potassium diet (Median = 6.24 ng/ml), z = -2.49, P = 0.013. Increased dietary potassium from fruit and vegetables improves FMD within 1 week in healthy men and women but the mechanisms for this effect remain unclear. ACTRN12612000822886. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Serine protease inhibitor A3K protects rabbit corneal endothelium from barrier function disruption induced by TNF-α.

    PubMed

    Hu, Jiaoyue; Zhang, Zhenhao; Xie, Hui; Chen, Lelei; Zhou, Yueping; Chen, Wensheng; Liu, Zuguo

    2013-08-09

    To determine if a serine protease inhibitor A3K (SA3K) reduces TNF-α-induced declines in rabbit corneal endothelial junctional barrier integrity. New Zealand rabbit corneas were incubated ex vivo for 24 hours in Dulbecco's modified Eagle's medium (DMEM) containing 10% FBS with or without TNF-α, in the presence or absence of SA3K at different concentrations. Corneal endothelial barrier function permeability was determined based on measurements of FITC-dextran tissue accumulation. Apical junctional complex (AJC) integrity was evaluated of zonula occludens-1 (ZO-1), vascular endothelial (VE)-cadherin, and filamentous actin (F-actin) and associated microtubules, as well as myosin light chain (MLC) by immunofluorescent staining, Western blot analysis, and/or RT-PCR. TNF-α (20 ng/mL) increased corneal endothelial FITC-dextran permeability by 1.8-fold compared with the untreated control. SA3K (100-200 nM) dose dependently suppressed TNF-α-induced increases in permeability. SA3K nearly completely reversed TNF-α-induced disruptions of tight junctional ZO-1 and subjacent adherens junctions VE-cadherin integrity. Interestingly, SA3K reversed TNF-α-induced disruption of AJC linkage to the cytoskeletal F-actin array by restoring F-actin double-band structures. SA3K also attenuated TNF-α-induced microtubule disassembly. Furthermore, SA3K blocked increases in MLC phosphorylation status elicited by TNF-α. SA3K exposure markedly reduced TNF-α-induced disruption of barrier structure and function in the rabbit corneal endothelium by maintaining AJC integrity. These protective effects are due to suppression of MLC activation. SA3K may have, in vivo, a therapeutic potential to offset TNF-α-induced declines in endothelial barrier structural integrity and function.

  16. Disruption of the endothelial barrier by proteases from the bacterial pathogen Pseudomonas aeruginosa: implication of matrilysis and receptor cleavage.

    PubMed

    Beaufort, Nathalie; Corvazier, Elisabeth; Mlanaoindrou, Saouda; de Bentzmann, Sophie; Pidard, Dominique

    2013-01-01

    , pseudomonal LasB thus appears to induce endothelial anoikis not only via matrilysis, as observed for many pro-apoptotic proteinases, but also via cleavage of some essential cell-to-cell and cell-to-matrix adhesion receptors implicated in the maintenance of the endothelial barrier.

  17. Effect of vitamin D on endothelial progenitor cells function.

    PubMed

    Hammer, Yoav; Soudry, Alissa; Levi, Amos; Talmor-Barkan, Yeela; Leshem-Lev, Dorit; Singer, Joel; Kornowski, Ran; Lev, Eli I

    2017-01-01

    Endothelial progenitor cells (EPCs) are a population of bone marrow-derived cells, which have an important role in the process of endothelialization and vascular repair following injury. Impairment of EPCs, which occurs in patients with diabetes, was shown to be related to endothelial dysfunction, coronary artery disease (CAD) and adverse clinical outcomes. Recent evidence has shown that calcitriol, the active hormone of vitamin D, has a favorable impact on the endothelium and cardiovascular system. There is limited data on the effect of vitamin D on EPCs function. To examine the in vitro effects of Calcitriol on EPCs from healthy subjects and patients with diabetes. Fifty-one patients with type 2 diabetes (60±11 years, 40% women, HbA1C: 9.1±0.8%) and 23 healthy volunteers were recruited. EPCs were isolated and cultured with and without calcitriol. The capacity of the cells to form colony-forming units (CFUs), their viability (measured by MTT assay), KLF-10 levels and angiogenic markers were evaluated after 1 week of culture. In diabetic patients, EPC CFUs and cell viability were higher in EPCs exposed to calcitriol vs. EPCs not exposed to calcitriol [EPC CFUs: 1.25 (IQR 1.0-2.0) vs. 0.5 (IQR 0.5-1.9), p < 0.001; MTT:0.62 (IQR 0.44-0.93) vs. 0.52 (IQR 0.31-0.62), p = 0.001]. KLF-10 levels tended to be higher in EPCs exposed to vitamin D, with no differences in angiopoietic markers. In healthy subjects, calcitriol supplementation also resulted in higher cell viability [MTT: 0.23 (IQR 0.11-0.46) vs. 0.19 (0.09-0.39), p = 0.04], but without differences in CFU count or angiopoietic markers. In patients with diabetes mellitus, in vitro vitamin D supplementation improved EPCs capacity to form colonies and viability. Further studies regarding the mechanisms by which vitamin D exerts its effect are required.

  18. Adiponectin in Fresh Frozen Plasma Contributes to Restoration of Vascular Barrier Function After Hemorrhagic Shock.

    PubMed

    Deng, Xiyun; Cao, Yanna; Huby, Maria P; Duan, Chaojun; Baer, Lisa; Peng, Zhanglong; Kozar, Rosemary A; Doursout, Marie-Francoise; Holcomb, John B; Wade, Charles E; Ko, Tien C

    2016-01-01

    Hemorrhagic shock is the leading cause of preventable deaths in civilian and military trauma. Use of fresh frozen plasma (FFP) in patients requiring massive transfusion is associated with improved outcomes. FFP contains significant amounts of adiponectin, which is known to have vascular protective function. We hypothesize that FFP improves vascular barrier function largely via adiponectin. Plasma adiponectin levels were measured in 19 severely injured patients in hemorrhagic shock (HS). Compared with normal individuals, plasma adiponectin levels decreased to 49% in HS patients before resuscitation (P < 0.05) and increased to 64% post-resuscitation (but not significant). In a HS mouse model, we demonstrated a similar decrease in plasma adiponectin to 54% but a significant increase to 79% by FFP resuscitation compared with baseline (P < 0.05). HS disrupted lung vascular barrier function, leading to an increase in permeability. FFP resuscitation reversed these HS-induced effects. Immunodepletion of adiponectin from FFP abolished FFP's effects on blocking endothelial hyperpermeability in vitro, and on improving lung vascular barrier function in HS mice. Replenishment with adiponectin rescued FFP's effects. These findings suggest that adiponectin is an important component in FFP resuscitation contributing to the beneficial effects on vascular barrier function after HS.

  19. Adiponectin in Fresh Frozen Plasma Contributes to Restoration of Vascular Barrier Function after Hemorrhagic Shock

    PubMed Central

    Huby, Maria P.; Duan, Chaojun; Baer, Lisa; Peng, Zhanglong; Kozar, Rosemary A.; Doursout, Marie-Francoise; Holcomb, John B.; Wade, Charles E.; Ko, Tien C.

    2015-01-01

    Hemorrhagic shock is the leading cause of preventable deaths in civilian and military trauma. Use of fresh frozen plasma (FFP) in patients requiring massive transfusion is associated with improved outcomes. FFP contains significant amounts of adiponectin, which is known to have vascular protective function. We hypothesize that FFP improves vascular barrier function largely via adiponectin. Plasma adiponectin levels were measured in 19 severely injured patients in hemorrhagic shock (HS). Compared to normal individuals, plasma adiponectin levels decreased to 49% in HS patients prior to resuscitation (p<0.05) and increased to 64% post resuscitation (but not significant). In a HS mouse model, we demonstrated a similar decrease in plasma adiponectin to 54% but a significant increase to 79% by FFP resuscitation compared to baseline (p<0.05). HS disrupted lung vascular barrier function, leading to an increase in permeability. FFP resuscitation reversed these HS-induced effects. Immunodepletion of adiponectin from FFP abolished FFP's effects on blocking endothelial hyperpermeability in vitro, and on improving lung vascular barrier function in HS mice. Replenishment with adiponectin rescued FFP's effects. These findings suggest that adiponectin is an important component in FFP resuscitation contributing to the beneficial effects on vascular barrier function after HS. PMID:26263440

  20. Effects of Vitamin D on Blood Pressure and Endothelial Function

    PubMed Central

    2013-01-01

    Vitamin D deficiency is prevalent, primarily due to limited sun exposure, which may be observed in urban areas, or as a result of modern lifestyles. Common myths about vitamin D persist, including that it is mostly obtained from the diet and is only essential for bone and mineral homeostasis. Nonetheless, advances in biomedical science suggest that vitamin D is a hormone that is integral to numerous physiologic functions in most cells and tissues. Therefore, abnormal vitamin D levels may contribute to health disturbances. A number of recent reports on potential associations between vitamin D deficiency and cardiovascular disease have highlighted its role in this system. A focus over the previous decade has been to better understand the mechanisms behind vitamin D regulation and the pathophysiology associated with suboptimal vitamin D levels. Vitamin D deficiency is highly associated with the incidence of cardiovascular diseases, even when considering other well-known risk factors. In this process, the renin-angiotensin system is disrupted, and hypertension and endothelial dysfunction contribute to the risk of cardiovascular disease. Likewise, clinical outcomes upon the normalization of vitamin D levels have been investigated in different patient populations. It makes sense that vitamin D supplementation to improve vitamin D status among vitamin D-deficient individuals could be useful without requiring a sudden lifestyle change. This manuscript provides a brief overview of vitamin D metabolism and the vitamin D receptor. It also summarizes the current clinical research relating to vitamin D supplementation and its effects on hypertension and endothelial dysfunction in cardiovascular medicine. PMID:24227938

  1. Obstructive sleep apnea syndrome, vascular pathology, endothelial function and endothelial cells and circulating microparticles.

    PubMed

    Stiefel, Pablo; Sánchez-Armengol, Maria Angeles; Villar, José; Vallejo-Vaz, Antonio; Moreno-Luna, Rafael; Capote, Francisco

    2013-08-01

    Accelerated atherosclerosis and increased cardiovascular risk are frequently reported in patients with obstructive sleep apnea (OSA) syndrome. In this article the authors attempt a review of the current understanding of the relationship between vascular risk and OSA syndrome based on large cohort studies that related the disease to several cardiovascular risk factors and vascular pathologies. We also discuss the pathophysiological mechanisms that may be involved in this relationship, starting with endothelial dysfunction and its mediators. These include an increased oxidative stress and inflammation as well as several disorders of coagulation and lipid metabolism. Moreover, circulating microparticles from activated leukocytes (CD62L_MPs) are higher in patients with OSA and there is a positive correlation between circulating levels of CD62L_MPs and nocturnal hypoxemia severity. Finally, circulating level of endothelial microparticles and circulating endothelial cells seem to be increased in patients with OSA. Also, endothelial progenitor cells are reduced and plasma levels of the vascular endothelial growth factor are increased.

  2. Standards for the Protection of Skin Barrier Function.

    PubMed

    Giménez-Arnau, Ana

    2016-01-01

    The skin is a vital organ, and through our skin we are in close contact with the entire environment. If we lose our skin we lose our life. The barrier function of the skin is mainly driven by the sophisticated epidermis in close relationship with the dermis. The epidermal epithelium is a mechanically, chemically, biologically and immunologically active barrier submitted to continuous turnover. The barrier function of the skin needs to be protected and restored. Its own physiology allows its recovery, but many times this is not sufficient. This chapter is focused on the standards to restore, treat and prevent barrier function disruption. These standards were developed from a scientific, academic and clinical point of view. There is a lack of standardized administrative recommendations. Still, there is a walk to do that will help to reduce the social and economic burden of diseases characterized by an abnormal skin barrier function.

  3. Anandamide inhibits Theiler's virus induced VCAM-1 in brain endothelial cells and reduces leukocyte transmigration in a model of blood brain barrier by activation of CB1 receptors

    PubMed Central

    2011-01-01

    Background VCAM-1 represents one of the most important adhesion molecule involved in the transmigration of blood leukocytes across the blood-brain barrier (BBB) that is an essential step in the pathogenesis of MS. Several evidences have suggested the potential therapeutic value of cannabinoids (CBs) in the treatment of MS and their experimental models. However, the effects of endocannabinoids on VCAM-1 regulation are poorly understood. In the present study we investigated the effects of anandamide (AEA) in the regulation of VCAM-1 expression induced by Theiler's virus (TMEV) infection of brain endothelial cells using in vitro and in vivo approaches. Methods i) in vitro: VCAM-1 was measured by ELISA in supernatants of brain endothelial cells infected with TMEV and subjected to AEA and/or cannabinoid receptors antagonist treatment. To evaluate the functional effect of VCAM-1 modulation we developed a blood brain barrier model based on a system of astrocytes and brain endothelial cells co-culture. ii) in vivo: CB1 receptor deficient mice (Cnr1-/-) infected with TMEV were treated with the AEA uptake inhibitor UCM-707 for three days. VCAM-1 expression and microglial reactivity were evaluated by immunohistochemistry. Results Anandamide-induced inhibition of VCAM-1 expression in brain endothelial cell cultures was mediated by activation of CB1 receptors. The study of leukocyte transmigration confirmed the functional relevance of VCAM-1 inhibition by AEA. In vivo approaches also showed that the inhibition of AEA uptake reduced the expression of brain VCAM-1 in response to TMEV infection. Although a decreased expression of VCAM-1 by UCM-707 was observed in both, wild type and CB1 receptor deficient mice (Cnr1-/-), the magnitude of VCAM-1 inhibition was significantly higher in the wild type mice. Interestingly, Cnr1-/- mice showed enhanced microglial reactivity and VCAM-1 expression following TMEV infection, indicating that the lack of CB1 receptor exacerbated

  4. ADAM12 and ADAM17 are essential molecules for hypoxia-induced impairment of neural vascular barrier function

    PubMed Central

    Cui, Dan; Arima, Mitsuru; Takubo, Keiyo; Kimura, Tokuhiro; Horiuchi, Keisuke; Minagawa, Takuya; Matsuda, Satoshi; Ikeda, Eiji

    2015-01-01

    Neural vascular barrier is essential for the life of multicellular organisms, and its impairment by tissue hypoxia is known to be a central of pathophysiology accelerating the progression of various intractable neural diseases. Therefore, the molecules involved in hypoxia-induced impairment of vascular barrier can be the targets to establish new therapies for intractable diseases. Here, we demonstrate that a disintegrin and metalloproteinases (ADAMs) 12 and 17 expressed in endothelial cells are the molecules responsible for the impairment of neural vascular barrier by hypoxia. Brain microvascular endothelial cells in vitro lost their barrier properties immediately after hypoxic stimulation through diminished localization of claudin-5, a tight junction molecule, on cell membranes. Hypoxic disappearance of claudin-5 from cell membranes and the consequent loss of barrier properties were completely suppressed by inhibition of the metalloproteinase activity which was found to be attributed to ADAM12 and ADAM17. Inhibition of either ADAM12 or ADAM17 was sufficient to rescue the in vivo neural vasculature under hypoxia from the loss of barrier function. This is the first report to specify the molecules which are responsible for hypoxia-induced impairment of neural vascular barrier and furthermore can be the targets of new therapeutic strategies for intractable neural diseases. PMID:26242473

  5. ADAM12 and ADAM17 are essential molecules for hypoxia-induced impairment of neural vascular barrier function.

    PubMed

    Cui, Dan; Arima, Mitsuru; Takubo, Keiyo; Kimura, Tokuhiro; Horiuchi, Keisuke; Minagawa, Takuya; Matsuda, Satoshi; Ikeda, Eiji

    2015-08-05

    Neural vascular barrier is essential for the life of multicellular organisms, and its impairment by tissue hypoxia is known to be a central of pathophysiology accelerating the progression of various intractable neural diseases. Therefore, the molecules involved in hypoxia-induced impairment of vascular barrier can be the targets to establish new therapies for intractable diseases. Here, we demonstrate that a disintegrin and metalloproteinases (ADAMs) 12 and 17 expressed in endothelial cells are the molecules responsible for the impairment of neural vascular barrier by hypoxia. Brain microvascular endothelial cells in vitro lost their barrier properties immediately after hypoxic stimulation through diminished localization of claudin-5, a tight junction molecule, on cell membranes. Hypoxic disappearance of claudin-5 from cell membranes and the consequent loss of barrier properties were completely suppressed by inhibition of the metalloproteinase activity which was found to be attributed to ADAM12 and ADAM17. Inhibition of either ADAM12 or ADAM17 was sufficient to rescue the in vivo neural vasculature under hypoxia from the loss of barrier function. This is the first report to specify the molecules which are responsible for hypoxia-induced impairment of neural vascular barrier and furthermore can be the targets of new therapeutic strategies for intractable neural diseases.

  6. Cardiac microvascular endothelial cells express a functional Ca+ -sensing receptor.

    PubMed

    Berra Romani, Roberto; Raqeeb, Abdul; Laforenza, Umberto; Scaffino, Manuela Federica; Moccia, Francesco; Avelino-Cruz, Josè Everardo; Oldani, Amanda; Coltrini, Daniela; Milesi, Veronica; Taglietti, Vanni; Tanzi, Franco

    2009-01-01

    The mechanism whereby extracellular Ca(2+) exerts the endothelium-dependent control of vascular tone is still unclear. In this study, we assessed whether cardiac microvascular endothelial cells (CMEC) express a functional extracellular Ca(2+)-sensing receptor (CaSR) using a variety of techniques. CaSR mRNA was detected using RT-PCR, and CaSR protein was identified by immunocytochemical analysis. In order to assess the functionality of the receptor, CMEC were loaded with the Ca(2+)-sensitive fluorochrome, Fura-2/AM. A number of CaSR agonists, such as spermine, Gd(3+), La(3+) and neomycin, elicited a heterogeneous intracellular Ca(2+) signal, which was abolished by disruption of inositol 1,4,5-trisphosphate (InsP(3)) signaling and by depletion of intracellular stores with cyclopiazonic acid. The inhibition of the Na(+)/Ca(2+) exchanger upon substitution of extracellular Na(+) unmasked the Ca(2+) signal triggered by an increase in extracellular Ca(2+) levels. Finally, aromatic amino acids, which function as allosteric activators of CaSR, potentiated the Ca(2+) response to the CaSR agonist La(3+). These data provide evidence that CMEC express CaSR, which is able to respond to physiological agonists by mobilizing Ca(2+) from intracellular InsP(3)-sensitive stores. Copyright 2008 S. Karger AG, Basel.

  7. Activated T cell trans-endothelial migration relies on myosin-IIA contractility for squeezing the cell nucleus through endothelial cell barriers.

    PubMed

    Jacobelli, Jordan; Estin Matthews, Miriam; Chen, Stephanie; Krummel, Matthew F

    2013-01-01

    Following activation, T cells are released from lymph nodes to traffic via the blood to effector sites. The re-entry of these activated T cells into tissues represents a critical step for them to carry out local effector functions. Here we have assessed defects in effector T cells that are acutely depleted in Myosin-IIA (MyoIIA) and show a T cell intrinsic requirement for this motor to facilitate the diapedesis step of extravasation. We show that MyoIIA accumulates at the rear of T cells undergoing trans-endothelial migration. T cells can extend protrusions and project a substantial portion of their cytoplasm through the endothelial wall in the absence of MyoIIA. However, this motor protein plays a crucial role in allowing T cells to complete the movement of their relatively rigid nucleus through the endothelial junctions. In vivo, this defect manifests as poor entry into lymph nodes, tumors and into the spinal cord, during tissue-specific autoimmunity, but not the spleen. This suggests that therapeutic targeting of this molecule may allow for differential attenuation of tissue-specific inflammatory responses.

  8. PGC-1α dictates endothelial function through regulation of eNOS expression

    PubMed Central

    Craige, Siobhan M.; Kröller-Schön, Swenja; Li, Chunying; Kant, Shashi; Cai, Shenghe; Chen, Kai; Contractor, Mayur M.; Pei, Yongmei; Schulz, Eberhard; Keaney, John F.

    2016-01-01

    Endothelial dysfunction is a characteristic of many vascular related diseases such as hypertension. Peroxisome proliferator activated receptor gamma, coactivator 1α (PGC-1α) is a unique stress sensor that largely acts to promote adaptive responses. Therefore, we sought to define the role of endothelial PGC-1α in vascular function using mice with endothelial specific loss of function (PGC-1α EC KO) and endothelial specific gain of function (PGC-1α EC TG). Here we report that endothelial PGC-1α is suppressed in angiotensin-II (ATII)-induced hypertension. Deletion of endothelial PGC-1α sensitized mice to endothelial dysfunction and hypertension in response to ATII, whereas PGC-1α EC TG mice were protected. Mechanistically, PGC-1α promotes eNOS expression and activity, which is necessary for protection from ATII-induced dysfunction as mice either treated with an eNOS inhibitor (LNAME) or lacking eNOS were no longer responsive to transgenic endothelial PGC-1α expression. Finally, we determined that the orphan nuclear receptor, estrogen related receptor α (ERRα) is required to coordinate the PGC-1α -induced eNOS expression. In conclusion, endothelial PGC-1α expression protects from vascular dysfunction by promoting NO• bioactivity through ERRα induced expression of eNOS. PMID:27910955

  9. Methodological issues in the assessment of skin microvascular endothelial function in humans.

    PubMed

    Cracowski, Jean-Luc; Minson, Christopher T; Salvat-Melis, Muriel; Halliwill, John R

    2006-09-01

    The study of microvascular function can be performed in humans using laser Doppler flowmetry of the skin. This technology lends itself to a wide range of applications for studying the endothelial function of skin blood vessels. We review the advantages and limitations of postocclusive hyperemia, local thermal hyperemia, acetylcholine iontophoresis, flowmotion and association with microdialysis as tools with which to investigate skin microvascular endothelial function in humans. Postocclusive hyperemia, thermal hyperemia and acetylcholine iontophoresis provide integrated indexes of microvascular function rather than specific endothelial markers. However, they are valuable tools and can be used as surrogate endpoints in clinical trials in which the assessment of microvascular function in humans is required.

  10. Vascular Endothelial Growth Factor Increases during Blood-Brain Barrier-Enhanced Permeability Caused by Phoneutria nigriventer Spider Venom

    PubMed Central

    Mendonça, Monique C. P.; Soares, Edilene S.; Stávale, Leila M.; Kalapothakis, Evanguedes; Cruz-Höfling, Maria Alice

    2014-01-01

    Phoneutria nigriventer spider accidental envenomation provokes neurotoxic manifestations, which when critical, results in epileptic-like episodes. In rats, P. nigriventer venom (PNV) causes blood-brain barrier breakdown (BBBb). The PNV-induced excitotoxicity results from disturbances on Na+, K+ and Ca2+ channels and glutamate handling. The vascular endothelial growth factor (VEGF), beyond its angiogenic effect, also, interferes on synaptic physiology by affecting the same ion channels and protects neurons from excitotoxicity. However, it is unknown whether VEGF expression is altered following PNV envenomation. We found that adult and neonates rats injected with PNV showed immediate neurotoxic manifestations which paralleled with endothelial occludin, β-catenin, and laminin downregulation indicative of BBBb. In neonate rats, VEGF, VEGF mRNA, and Flt-1 receptors, glutamate decarboxylase, and calbindin-D28k increased in Purkinje neurons, while, in adult rats, the BBBb paralleled with VEGF mRNA, Flk-1, and calbindin-D28k increases and Flt-1 decreases. Statistically, the variable age had a role in such differences, which might be due to age-related unequal maturation of blood-brain barrier (BBB) and thus differential cross-signaling among components of the glial neurovascular unit. The concurrent increases in the VEGF/Flt-1/Flk-1 system in the cerebellar neuron cells and the BBBb following PNV exposure might imply a cytokine modulation of neuronal excitability consequent to homeostatic perturbations induced by ion channels-acting PNV neuropeptides. Whether such modulation represents neuroprotection needs further investigation. PMID:25247186

  11. Differential roles for endothelial ICAM-1, ICAM-2, and VCAM-1 in shear-resistant T cell arrest, polarization, and directed crawling on blood-brain barrier endothelium.

    PubMed

    Steiner, Oliver; Coisne, Caroline; Cecchelli, Roméo; Boscacci, Rémy; Deutsch, Urban; Engelhardt, Britta; Lyck, Ruth

    2010-10-15

    Endothelial ICAM-1 and ICAM-2 were shown to be essential for T cell diapedesis across the blood-brain barrier (BBB) in vitro under static conditions. Crawling of T cells prior to diapedesis was only recently revealed to occur preferentially against the direction of blood flow on the endothelial surface of inflamed brain microvessels in vivo. Using live cell-imaging techniques, we prove that Th1 memory/effector T cells predominantly crawl against the direction of flow on the surface of BBB endothelium in vitro. Analysis of T cell interaction with wild-type, ICAM-1-deficient, ICAM-2-deficient, or ICAM-1 and ICAM-2 double-deficient primary mouse brain microvascular endothelial cells under physiological flow conditions allowed us to dissect the individual contributions of endothelial ICAM-1, ICAM-2, and VCAM-1 to shear-resistant T cell arrest, polarization, and crawling. Although T cell arrest was mediated by endothelial ICAM-1 and VCAM-1, T cell polarization and crawling were mediated by endothelial ICAM-1 and ICAM-2 but not by endothelial VCAM-1. Therefore, our data delineate a sequential involvement of endothelial ICAM-1 and VCAM-1 in mediating shear-resistant T cell arrest, followed by endothelial ICAM-1 and ICAM-2 in mediating T cell crawling to sites permissive for diapedesis across BBB endothelium.

  12. Effect of thiol-oxidation of glutathione with diamide on corneal endothelial function, junctional complexes, and microfilaments.

    PubMed

    Edelhauser, H F; Van Horn, D L; Miller, P; Pederson, H J

    1976-03-01

    Intracellular-reduced glutathione (GSH) was removed by thiol-oxidation with diamide during in vitro perfusion of the corneal endothelium. By 15 min the normal mosaic-like pattern of the endothelial cells was disrupted by serpentine-like lines of cell separation at the cell juntions. After 45 min of perfusion, infividual clusters of cells formed cup-shaped islands. The resultant exposure of Descemet's membrane to the perfusion solution resulted in corneal swelling. Transmission electron microscopy revealed that the endothelial cells separated at the apical junctions and that the microfilaments in the apical cytoplasm of cells formed dense bands, whereas the other subcellular organelles were normal in appearance. The change in cellular shape may be due to loss of cellular adhesion which results in the condensation of the microfilaments or contraction of the microfilaments. The addition of glucose to the perfusate prevented the diamide effect, and the diamide effect could be reversed upon removal and perfusion of a glutathione bicarbonate Ringer's solution. These results suggest that the ratio of reduced to oxidized glutathione in the endothelial cells plays a role in the maintenance of the endothelial cell barrier function.

  13. Effect of thiol-oxidation of glutathione with diamide on corneal endothelial function, junctional complexes, and microfilaments

    PubMed Central

    1976-01-01

    Intracellular-reduced glutathione (GSH) was removed by thiol-oxidation with diamide during in vitro perfusion of the corneal endothelium. By 15 min the normal mosaic-like pattern of the endothelial cells was disrupted by serpentine-like lines of cell separation at the cell juntions. After 45 min of perfusion, infividual clusters of cells formed cup-shaped islands. The resultant exposure of Descemet's membrane to the perfusion solution resulted in corneal swelling. Transmission electron microscopy revealed that the endothelial cells separated at the apical junctions and that the microfilaments in the apical cytoplasm of cells formed dense bands, whereas the other subcellular organelles were normal in appearance. The change in cellular shape may be due to loss of cellular adhesion which results in the condensation of the microfilaments or contraction of the microfilaments. The addition of glucose to the perfusate prevented the diamide effect, and the diamide effect could be reversed upon removal and perfusion of a glutathione bicarbonate Ringer's solution. These results suggest that the ratio of reduced to oxidized glutathione in the endothelial cells plays a role in the maintenance of the endothelial cell barrier function. PMID:1035910

  14. Contrasting pediatric and adult cerebral malaria: the role of the endothelial barrier.

    PubMed

    Hawkes, Michael; Elphinstone, Robyn E; Conroy, Andrea L; Kain, Kevin C

    2013-08-15

    Malaria affects millions of people around the world and a small subset of those infected develop cerebral malaria. The clinical presentation of cerebral malaria differs between children and adults, and it has been suggested that age-related changes in the endothelial response may account for some of these differences. During cerebral malaria, parasites sequester within the brain microvasculature but do not penetrate into the brain parenchyma and yet, the infection causes severe neurological symptoms. Endothelial dysfunction is thought to play an important role in mediating these adverse clinical outcomes. During infection, the endothelium becomes activated and more permeable, which leads to increased inflammation, hemorrhages, and edema in the surrounding tissue. We hypothesize that post-natal developmental changes, occurring in both endothelial response and the neurovascular unit, account for the differences observed in the clinical presentations of cerebral malaria in children compared with adults.

  15. A Triple Culture Model of the Blood-Brain Barrier Using Porcine Brain Endothelial cells, Astrocytes and Pericytes

    PubMed Central

    Thomsen, Louiza Bohn; Burkhart, Annette; Moos, Torben

    2015-01-01

    In vitro blood-brain barrier (BBB) models based on primary brain endothelial cells (BECs) cultured as monoculture or in co-culture with primary astrocytes and pericytes are useful for studying many properties of the BBB. The BECs retain their expression of tight junction proteins and efflux transporters leading to high trans-endothelial electric resistance (TEER) and low passive paracellular permeability. The BECs, astrocytes and pericytes are often isolated from small rodents. Larger species as cows and pigs however, reveal a higher yield, are readily available and have a closer resemblance to humans, which make them favorable high-throughput sources for cellular isolation. The aim of the present study has been to determine if the preferable combination of purely porcine cells isolated from the 6 months old domestic pigs, i.e. porcine brain endothelial cells (PBECs) in co-culture with porcine astrocytes and pericytes, would compare with PBECs co-cultured with astrocytes and pericytes isolated from newborn rats with respect to TEER value and low passive permeability. The astrocytes and pericytes were grown both as contact and non-contact co-cultures as well as in triple culture to examine their effects on the PBECs for barrier formation as revealed by TEER, passive permeability, and expression patterns of tight junction proteins, efflux transporters and the transferrin receptor. This syngenic porcine in vitro BBB model is comparable to triple cultures using PBECs, rat astrocytes and rat pericytes with respect to TEER formation, low passive permeability, and expression of hallmark proteins signifying the brain endothelium (tight junction proteins claudin 5 and occludin, the efflux transporters P-glycoprotein (PgP) and breast cancer related protein (BCRP), and the transferrin receptor). PMID:26241648

  16. A Triple Culture Model of the Blood-Brain Barrier Using Porcine Brain Endothelial cells, Astrocytes and Pericytes.

    PubMed

    Thomsen, Louiza Bohn; Burkhart, Annette; Moos, Torben

    2015-01-01

    In vitro blood-brain barrier (BBB) models based on primary brain endothelial cells (BECs) cultured as monoculture or in co-culture with primary astrocytes and pericytes are useful for studying many properties of the BBB. The BECs retain their expression of tight junction proteins and efflux transporters leading to high trans-endothelial electric resistance (TEER) and low passive paracellular permeability. The BECs, astrocytes and pericytes are often isolated from small rodents. Larger species as cows and pigs however, reveal a higher yield, are readily available and have a closer resemblance to humans, which make them favorable high-throughput sources for cellular isolation. The aim of the present study has been to determine if the preferable combination of purely porcine cells isolated from the 6 months old domestic pigs, i.e. porcine brain endothelial cells (PBECs) in co-culture with porcine astrocytes and pericytes, would compare with PBECs co-cultured with astrocytes and pericytes isolated from newborn rats with respect to TEER value and low passive permeability. The astrocytes and pericytes were grown both as contact and non-contact co-cultures as well as in triple culture to examine their effects on the PBECs for barrier formation as revealed by TEER, passive permeability, and expression patterns of tight junction proteins, efflux transporters and the transferrin receptor. This syngenic porcine in vitro BBB model is comparable to triple cultures using PBECs, rat astrocytes and rat pericytes with respect to TEER formation, low passive permeability, and expression of hallmark proteins signifying the brain endothelium (tight junction proteins claudin 5 and occludin, the efflux transporters P-glycoprotein (PgP) and breast cancer related protein (BCRP), and the transferrin receptor).

  17. Role of Vascular Endothelial Growth Factor in the Breakdown of the Blood-Aqueous Barrier After Retinal Laser Photocoagulation in Pigmented Rabbits

    PubMed Central

    Chen, Muh-Shy; Chang, Ching-Chung; Lin, Chang-Ping; Wang, Peng-Chen; Lin, Li-Rong; Hou, Ping-Kang

    2012-01-01

    Abstract Purpose Retinal laser photocoagulation is used to treat a variety of retinal diseases. Breakdown of the blood-aqueous barrier has been noted after retinal laser photocoagulation. The effect of vascular endothelial growth factor (VEGF) on the function of the blood-aqueous barrier after retinal laser photocoagulation remains undetermined. The current study was designed to evaluate the relationship between intraocular levels of VEGF and breakdown of the blood-aqueous barrier after retinal laser photocoagulation in rabbits. Methods Pigmented rabbits were treated with retinal laser photocoagulation in one eye; the other served as control. Laser flare photometry was carried out on post-treatment days 1, 3, 7, and 14. Animals were sacrificed at the time period just mentioned postlaser, the eyes were removed, and samples of vitreous and aqueous humor were collected. Intraocular VEGF levels were measured by using an immunoassay. An intravitreal injection of VEGF was administered, and the aqueous flare intensity and VEGF levels in the aqueous and vitreous humor were measured at the time periods just mentioned. Results A significant increase in the aqueous flare intensity after retinal laser photocoagulation was noticed on postoperative day 1, with the values returning to baseline levels on day 14. The VEGF levels in the vitreous of the lasered eyes were significantly increased on day 1 compared with the nonlasered control eyes. The VEGF levels in the aqueous humor of the lasered eyes were also significantly increased on day 1 compared with the control eyes. An intravitreal injection of VEGF induced a significant increase in the aqueous flare intensity and VEGF levels in the aqueous and vitreous humor. Conclusions The current results suggested that retinal laser photocoagulation can produce a breakdown of the blood-aqueous barrier. VEGF may play a role in the blood-aqueous barrier dysfunction after retinal laser photocoagulation. PMID:22011077

  18. Effect of Hypergravity on Endothelial Cell Function and Gene Expression

    NASA Astrophysics Data System (ADS)

    Morbidelli, Lucia; Marziliano, Nicola; Basile, Venere; Pezzatini, Silvia; Romano, Giovanni; Conti, Antonio; Monici, Monica

    2009-01-01

    It is well known that endothelial cells (ECs), which play a major role in cardiovascular system functioning, are very sensitive to mechanical stimuli. It has been demonstrated that changes in inertial conditions (i.e. microgravity and hypergravity) can affect both phenotypic and genotypic expression in ECs. In this report we describe the effects of hypergravity on ECs isolated from bovine aorta (BAECs). ECs were repeatedly exposed to discontinuous hypergravity conditions (5 × 10 min at 10× g with 10 min at 1× g between sets), simulated in a hyperfuge. Then, cell morphology and metabolism were analyzed by autofluorescence techniques. The phenotypic expression of cytoskeleton constituents ( β-actin, vimentin, tubulin), adhesion and survival signals (integrins), mediators of inflammation and angiogenesis was evaluated by immunocytofluorescence. Quantitative PCR (Q-PCR) with Low Density Arrays (LDAs) was used to evaluate modifications in gene expression. After hypergravity exposure, no significant changes were observed in cell morphology and energy metabolism. Cells remained adherent to the substratum, but integrin distribution was modified. Accordingly, the cytoskeletal network reorganized, documenting cell activation. There was a reduction in expression of genes controlling vasoconstriction and inflammation. Proapoptotic signals were downregulated. On the whole, the results documented that hypergravity exposure maintained EC survival and function by activation of adaptive mechanisms.

  19. Cytotoxic effects of aflatoxin B1 on human brain microvascular endothelial cells of the blood-brain barrier.

    PubMed

    Qureshi, Humaira; Hamid, Saeed S; Ali, Syed Shayan; Anwar, Javeria; Siddiqui, Anwar Ali; Khan, Naveed Ahmed

    2015-05-01

    Aflatoxins are mycotoxins produced by Aspergillus spp. Although AFB1 is implicated as a carcinogen in hepatocellular carcinoma, brain autopsies in affected areas have revealed its presence in 81% of cases. Given its haematogenous spread, here we determined the cytotoxic effects of AFB1 on primary human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier, human umbilical vein endothelial cells (HUVEC) as well as immortalized epithelial cells of human hepatocellular carcinoma (Huh7). The cell types were exposed to AFB1 (3-32 nM) for 24 h and release of lactate dehydrogenase was measured as cell cytotoxicity marker. Furthermore, DNA was collected from both cell types and DNA adduct formation was determined by immunoblot using anti-AFB1-DNA adduct antibody. At 32 nM, AFB1 killed >85% HBMEC, while controls showed minimal effects (P < .05). Similar concentrations of AFB1 showed 22% cell death of HUVEC, while the same concentration did not kill Huh7. At low concentrations, in other words, 3.2 nM, AFB1 produced DNA adduct formation in HBMEC, while high concentration (32 nM) did not form DNA adducts. For HUVEC, 16 nM and 32 nM exhibited DNA adduct formation. For Huh7, 3.2 nM did not form DNA adducts, while 32 nM exhibited DNA adduct formation. For the first time, we report that AFB1 affected the viability of primary endothelial cells but not immortalized Huh7 cells. Cytotoxicity of brain endothelial cells suggests extra-hepatic complications post-AFB1 exposure.

  20. Polyploidy impairs human aortic endothelial cell function and is prevented by nicotinamide phosphoribosyltransferase.

    PubMed

    Borradaile, Nica M; Pickering, J Geoffrey

    2010-01-01

    Polyploid endothelial cells are found in aged and atherosclerotic arteries. However, whether increased chromosome content has an impact on endothelial cell function is unknown. We show here that human aortic endothelial cells become tetraploid as they approach replicative senescence. Furthermore, accumulation of tetraploid endothelial cells was accelerated during growth in high glucose. Interestingly, induction of polyploidy was completely prevented by modest overexpression of the NAD+ regenerating enzyme, nicotinamide phosphoribosyltransferase (Nampt). To determine the impact of polyploidy on endothelial cell function, independent of replicative senescence, we induced tetraploidy using the spindle poison, nocodazole. Global gene expression analyses of tetraploid endothelial cells revealed a dysfunctional phenotype characterized by a cell cycle arrest profile (decreased CCNE2/A2, RBL1, BUB1B; increased CDKN1A) and increased expression of genes involved in inflammation (IL32, TNFRSF21/10C, PTGS1) and extracellular matrix remodeling (COL5A1, FN1, MMP10/14). The protection from polyploidy conferred by Nampt was not associated with enhanced poly(ADP-ribose) polymerase-1 or sirtuin (SIRT) 2 activity, but with increased SIRT1 activity, which reduced cellular reactive oxygen species and the associated oxidative stress stimulus for the induction of polyploidy. We conclude that human aortic endothelial cells are prone to chromosome duplication that, in and of itself, can induce characteristics of endothelial dysfunction. Moreover, the emergence of polyploid endothelial cells during replicative aging and glucose overload can be prevented by optimizing the Nampt-SIRT1 axis.

  1. Cell surface levels of endothelial ICAM-1 influence the transcellular or paracellular T-cell diapedesis across the blood-brain barrier.

    PubMed

    Abadier, Michael; Haghayegh Jahromi, Neda; Cardoso Alves, Ludmila; Boscacci, Rémy; Vestweber, Dietmar; Barnum, Scott; Deutsch, Urban; Engelhardt, Britta; Lyck, Ruth

    2015-04-01

    The extravasation of CD4(+) effector/memory T cells (TEM cells) across the blood-brain barrier (BBB) is a crucial step in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) or multiple sclerosis (MS). Endothelial ICAM-1 and ICAM-2 are essential for CD4(+) TEM cell crawling on the BBB prior to diapedesis. Here, we investigated the influence of cell surface levels of endothelial ICAM-1 in determining the cellular route of CD4(+) TEM -cell diapedesis across cytokine treated primary mouse BBB endothelial cells under physiological flow. Inflammatory conditions, inducing high levels of endothelial ICAM-1, promoted rapid initiation of transcellular diapedesis of CD4(+) T cells across the BBB, while intermediate levels of endothelial ICAM-1 favored paracellular CD4(+) T-cell diapedesis. Importantly, the route of T-cell diapedesis across the BBB was independent of loss of BBB barrier properties. Unexpectedly, a low number of CD4(+) TEM cells was found to cross the inflamed BBB in the absence of endothelial ICAM-1 and ICAM-2 via an obviously alternatively regulated transcellular pathway. In vivo, this translated to the development of ameliorated EAE in ICAM-1(null) //ICAM-2(-/-) C57BL/6J mice. Taken together, our study demonstrates that cell surface levels of endothelial ICAM-1 rather than the inflammatory stimulus or BBB integrity influence the pathway of T-cell diapedesis across the BBB.

  2. Genetic variants of ApoE and ApoER2 differentially modulate endothelial function.

    PubMed

    Ulrich, Victoria; Konaniah, Eddy S; Herz, Joachim; Gerard, Robert D; Jung, Eunjeong; Yuhanna, Ivan S; Ahmed, Mohamed; Hui, David Y; Mineo, Chieko; Shaul, Philip W

    2014-09-16

    It is poorly understood why there is greater cardiovascular disease risk associated with the apolipoprotein E4 (apoE) allele vs. apoE3, and also greater risk with the LRP8/apolipoprotein E receptor 2 (ApoER2) variant ApoER2-R952Q. Little is known about the function of the apoE-ApoER2 tandem outside of the central nervous system. We now report that in endothelial cells apoE3 binding to ApoER2 stimulates endothelial NO synthase (eNOS) and endothelial cell migration, and it also attenuates monocyte-endothelial cell adhesion. However, apoE4 does not stimulate eNOS or endothelial cell migration or dampen cell adhesion, and alternatively it selectively antagonizes apoE3/ApoER2 actions. The contrasting endothelial actions of apoE4 vs. apoE3 require the N-terminal to C-terminal interaction in apoE4 that distinguishes it structurally from apoE3. Reconstitution experiments further reveal that ApoER2-R952Q is a loss-of-function variant of the receptor in endothelium. Carotid artery reendothelialization is decreased in ApoER2(-/-) mice, and whereas adenoviral-driven apoE3 expression in wild-type mice has no effect, apoE4 impairs reendothelialization. Moreover, in a model of neointima formation invoked by carotid artery endothelial denudation, ApoER2(-/-) mice display exaggerated neointima development. Thus, the apoE3/ApoER2 tandem promotes endothelial NO production, endothelial repair, and endothelial anti-inflammatory properties, and it prevents neointima formation. In contrast, apoE4 and ApoER2-R952Q display dominant-negative action and loss of function, respectively. Thus, genetic variants of apoE and ApoER2 impact cardiovascular health by differentially modulating endothelial function.

  3. Barrier protective effects of 2,4,6-trihydroxy-3-geranyl acetophenone on lipopolysaccharides-stimulated inflammatory responses in human umbilical vein endothelial cells.

    PubMed

    Chong, Yi Joong; Musa, Nazmi Firdaus; Ng, Chean Hui; Shaari, Khozirah; Israf, Daud Ahmad; Tham, Chau Ling

    2016-11-04

    2,4,6-trihydroxy-3-geranyl acetophenone (tHGA), is a phloroglucinol compound found naturally in Melicope ptelefolia. Melicope ptelefolia has been used traditionally for centuries as natural remedy for wound infections and inflammatory diseases. Endothelial barrier dysfunction is a pathological hallmark of many diseases and can be caused by lipopolysaccharides (LPS) stimulation. Therefore, this study aims to investigate the possible barrier protective effects of tHGA upon LPS-stimulated inflammatory responses in human umbilical vein endothelial cells (HUVECs). HUVECs were pretreated with tHGA prior to LPS stimulation, where inflammatory parameters including permeability, monocyte adhesion and migration, and release of pro-inflammatory mediators were examined. Additionally, the effect of tHGA on F-actin rearrangement and adhesion protein expression of LPS-stimulated HUVECs was evaluated. It was found that pretreatment with tHGA inhibited monocyte adhesion and transendothelial migration, reduced endothelial hyperpermeability and secretion of prostaglandin E2 (PGE2). Additionally, tHGA inhibited cytoskeletal rearrangement and adhesion protein expression on LPS-stimulated HUVECs. As the regulation of endothelial barrier dysfunction can be one of the therapeutic strategies to improve the outcome of inflammation, tHGA may be able to preserve vascular barrier integrity of endothelial cells following LPS-stimulated dysfunction, thereby endorsing its potential usefulness in vascular inflammatory diseases. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Associations of endothelial function and air temperature in diabetic subjects

    EPA Science Inventory

    Background and Objective: Epidemiological studies consistently show that air temperature is associated with changes in cardiovascular morbidity and mortality. However, the biological mechanisms underlying the association remain largely unknown. As one index of endothelial functio...

  5. Associations of endothelial function and air temperature in diabetic subjects

    EPA Science Inventory

    Background and Objective: Epidemiological studies consistently show that air temperature is associated with changes in cardiovascular morbidity and mortality. However, the biological mechanisms underlying the association remain largely unknown. As one index of endothelial functio...

  6. Endothelial NOS (NOS3) impairs myocardial function in developing sepsis.

    PubMed

    van de Sandt, Annette M; Windler, Rainer; Gödecke, Axel; Ohlig, Jan; Zander, Simone; Reinartz, Michael; Graf, Jürgen; van Faassen, Ernst E; Rassaf, Tienush; Schrader, Jürgen; Kelm, Malte; Merx, Marc W

    2013-03-01

    Endothelial nitric oxide synthase (NOS)3-derived nitric oxide (NO) modulates inotropic response and diastolic interval for optimal cardiac performance under non-inflammatory conditions. In sepsis, excessive NO production plays a key role in severe hypotension and myocardial dysfunction. We aimed to determine the role of NOS3 on myocardial performance, NO production, and time course of sepsis development. NOS3(-/-) and C57BL/6 wildtype mice were rendered septic by cecum ligation and puncture (CLP). Cardiac function was analyzed by serial echocardiography, in vivo pressure and isolated heart measurements. Cardiac output (CO) increased to 160 % of baseline at 10 h after sepsis induction followed by a decline to 63 % of baseline after 18 h in wildtype mice. CO was unaltered in septic NOS3(-/-) mice. Despite the hyperdynamic state, cardiac function and mean arterial pressure were impaired in septic wildtype as early as 6 h post CLP. At 12 h, cardiac function in septic wildtype was refractory to catecholamines in vivo and respective isolated hearts showed impaired pressure development and limited coronary flow reserve. Hemodynamics remained stable in NOS3(-/-) mice leading to significant survival benefit. Unselective NOS inhibition in septic NOS3(-/-) mice diminished this survival benefit. Plasma NO( x )- and local myocardial NO( x )- and NO levels (via NO spin trapping) demonstrated enhanced NO( x )- and bioactive NO levels in septic wildtype as compared to NOS3(-/-) mice. Significant contribution by inducible NOS (NOS2) during this early phase of sepsis was excluded. Our data suggest that NOS3 relevantly contributes to bioactive NO pool in developing sepsis resulting in impaired cardiac contractility.

  7. An Epoxyisoprostane is a Major Regulator of Endothelial Cell Function

    PubMed Central

    Zhong, Wei; Springstead, James R.; Al-Mubarak, Ramea; Lee, Sangderk; Li, Rongsong; Emert, Benjamin; Berliner, Judith A.; Jung, Michael E.

    2014-01-01

    The goal of these studies was to determine the effect of 5,6-epoxyisoprostane, EI, on human aortic endothelial cells (HAEC). EI can form as a phospholipase product of 1-palmitoyl-2-(5,6-epoxyisoprostane E2)-sn-glycero-3-phosphocholine, PEIPC, a pro-inflammatory molecule that accumulates in sites of inflammation where phospholipases are also increased. To determine the effect of EI on HAEC, we synthesized several stereoisomers of EI using a convergent approach from the individual optically pure building blocks, the epoxyaldehydes 5 and 6 and the bromoenones 14 and 16. The desired stereoisomer of EI can be prepared from these materials in only six operations and thus large amounts of the product can be obtained. The trans/trans isomers had the most potent activity, suggesting specificity in the interaction of EI with the cell surface. EI has potent anti-inflammatory effects in HAEC. EI strongly inhibits the production of MCP-1, a major monocyte chemotactic factor, and either decreases or minimally increases the levels of ten pro-inflammatory molecules increased by PEIPC. EI also strongly downregulates the inflammatory effects of IL-1β, a major inflammatory cytokine. Thus EI, a hydrolytic product of PEIPC, has potent anti-inflammatory function. PMID:24117045

  8. Impairment of Endothelial Function by Little Cigar Secondhand Smoke

    PubMed Central

    Liu, Jiangtao; Wang, Xiaoyin; Narayan, Shilpa; Glantz, Stanton A.; Schick, Suzaynn F.; Springer, Matthew L.

    2015-01-01

    Objectives Little cigars and cigarillos are gaining in popularity as cigarette use wanes, mainly due to relaxed regulatory standards that make them cheaper, easier to buy individually, and available in a variety of flavors not allowed in cigarettes. To address whether they should be regulated as strictly as cigarettes, we investigated whether little cigar secondhand smoke (SHS) decreases vascular endothelial function like that of cigarettes. Methods We exposed rats to SHS from little cigars, cigarettes, or chamber air, for 10 minutes and measured the resulting acute impairment of arterial flow-mediated dilation (FMD). Results SHS from both little cigars and cigarettes impaired FMD. Impairment was greater after exposure to little cigar SHS than by cigarette SHS relative to pre-exposure values, although the post-exposure FMD values were not significantly different from each other. Conclusions Exposure to little cigar SHS leads to impairment of FMD that is at least equal to that resulting from similar levels of cigarette SHS. Our findings support the need to prevent even brief exposure to little cigar SHS, and support tobacco control policies that regulate little cigars as strictly as cigarettes. PMID:26753171

  9. SIRT1 reduces endothelial activation without affecting vascular function in ApoE-/- mice.

    PubMed

    Stein, Sokrates; Schäfer, Nicola; Breitenstein, Alexander; Besler, Christian; Winnik, Stephan; Lohmann, Christine; Heinrich, Kathrin; Brokopp, Chad E; Handschin, Christoph; Landmesser, Ulf; Tanner, Felix C; Lüscher, Thomas F; Matter, Christian M

    2010-06-01

    Excessive production of reactive oxygen species (ROS) contributes to progression of atherosclerosis, at least in part by causing endothelial dysfunction and inflammatory activation. The class III histone deacetylase SIRT1 has been implicated in extension of lifespan. In the vasculature,SIRT1 gain-of-function using SIRT1 overexpression or activation has been shown to improve endothelial function in mice and rats via stimulation of endothelial nitric oxide (NO) synthase (eNOS). However, the effects of SIRT1 loss-of-function on the endothelium in atherosclerosis remain to be characterized. Thus, we have investigated the endothelial effects of decreased endogenous SIRT1 in hypercholesterolemic ApoE-/- mice. We observed no difference in endothelial relaxation and eNOS (Ser1177) phosphorylation between 20-week old male atherosclerotic ApoE-/- SIRT1+/- and ApoE-/- SIRT1+/+ mice. However, SIRT1 prevented endothelial superoxide production, inhibited NF-kappaB signaling, and diminished expression of adhesion molecules. Treatment of young hypercholesterolemic ApoE-/- SIRT1+/- mice with lipopolysaccharide to boost NF-kappaB signaling led to a more pronounced endothelial expression of ICAM-1 and VCAM-1 as compared to ApoE-/- SIRT1+/+ mice. In conclusion, endogenous SIRT1 diminishes endothelial activation in ApoE-/- mice, but does not affect endothelium-dependent vasodilatation.

  10. SIRT1 reduces endothelial activation without affecting vascular function in ApoE-/- mice

    PubMed Central

    Stein, Sokrates; Schäfer, Nicola; Breitenstein, Alexander; Besler, Christian; Winnik, Stephan; Lohmann, Christine; Heinrich, Kathrin; Brokopp, Chad E.; Handschin, Christoph; Landmesser, Ulf; Tanner, Felix C.; Lüscher, Thomas F.; Matter, Christian M.

    2010-01-01

    Excessive production of reactive oxygen species (ROS) contributes to progression of atherosclerosis, at least in part by causing endothelial dysfunction and inflammatory activation. The class III histone deacetylase SIRT1 has been implicated in extension of lifespan. In the vasculature,SIRT1 gain-of-function using SIRT1 overexpression or activation has been shown to improve endothelial function in mice and rats via stimulation of endothelial nitric oxide (NO) synthase (eNOS). However, the effects of SIRT1 loss-of-function on the endothelium in atherosclerosis remain to be characterized. Thus, we have investigated the endothelial effects of decreased endogenous SIRT1 in hypercholesterolemic ApoE-/- mice. We observed no difference in endothelial relaxation and eNOS (Ser1177) phosphorylation between 20-week old male atherosclerotic ApoE-/- SIRT1+/- and ApoE-/- SIRT1+/+ mice. However, SIRT1 prevented endothelial superoxide production, inhibited NF-κB signaling, and diminished expression of adhesion molecules. Treatment of young hypercholesterolemic ApoE-/- SIRT1+/- mice with lipopolysaccharide to boost NF-κB signaling led to a more pronounced endothelial expression of ICAM-1 and VCAM-1 as compared to ApoE-/- SIRT1+/+ mice. In conclusion, endogenous SIRT1 diminishes endothelial activation in ApoE-/- mice, but does not affect endothelium-dependent vasodilatation. PMID:20606253

  11. Assessing endothelial function and providing calibrated UFMD data using a blood pressure cuff

    DOEpatents

    Maltz, Jonathan S.

    2017-08-22

    Methods and apparatus are provided for assessing endothelial function in a mammal. In certain embodiments the methods involve using a cuff to apply pressure to an artery in a subject to determine a plurality of baseline values for a parameter related to endothelial function as a function of applied pressure (P.sub.m); b) applying a stimulus to the subject; and applying external pressure P.sub.m to the artery to determine a plurality of stimulus-effected values for the parameter related to endothelial function as a function of applied pressure (P.sub.m); where the baseline values are determined from measurements made when said mammal is not substantially effected by said stimulus and differences in said baseline values and said stimulus-effected values provide a measure of endothelial function in said mammal.

  12. Effect of nitrite on endothelial function in isolated lung.

    PubMed

    Ehrhart, I C; Zou, L; Theodorakis, M J; Parkerson, J B; Gu, X; Caldwell, R B; Catravas, J D

    2000-06-01

    Nitrated tyrosine, implicated in protein dysfunction, is increased in various tissues in association with diverse pathological processes. Angiotensin converting enzyme (ACE) is a luminal vascular endothelial enzyme whose dysfunction is an early sign of endothelial injury. ACE contains a tyrosine critical for its enzymatic activity. Others have shown that nitrite exacerbates the ACE dysfunction of cultured endothelial cells in contact with activated polymorphonuclear neutrophils (PMN). We hypothesized that exogenous nitrite would enhance endothelial ACE dysfunction associated with PMN activation in the isolated lung. Rats received lipopolysaccharide (LPS) 2 h prior to isolated lung perfusion with Ficoll containing buffer. Either formyl-Met-Leu-Phe (fMLP, 10(-7) M) or phorbol myristate acetate (PMA, 10(-7) M) was used to activate PMN in lungs treated or not treated with 300-microM nitrite. A first pass indicator dilution method and first order reaction kinetics were used to determine ACE activity, while lung Ficoll content served as an index of vascular permeability. Both fMLP and PMA decreased endothelial ACE activity and increased pulmonary artery pressure, edema and vascular permeability. Exogenous nitrate did not potentiate the decrease in ACE activity, the lung injury or nitrotyrosine immunoreactivity of lung homogenates. In contrast to observations in cultured endothelial cells, our findings in the whole lung are compatible with the speculation of others that the rat lung has an unidentified factor, which minimizes accumulation of nitrated proteins.

  13. [Functional regulation of endothelial Myosin light chain kinase in extravascular migration of fibrosarcoma cells].

    PubMed

    Xin, Hua; Han, Zhen-guo

    2009-03-01

    To evaluate the functional regulation of endothelial Myosin light chain kinase (MLCK) in extravascular migration of fibrosarcoma HT1080 cells. An in vitro model of fibrosarcoma cell transmigration across a monolayer of HUVEC cultured on collagen gel was applied to observe extravascular migration of HT1080 cells,and were the electrical resistance of HUVEC monolayer and endothelial MLC phosphorylation in extravascular migration of HT1080 cells. HT1080 cells migrated through endothelial cells into collagen gel, the electrical resistance of a HUVEC monolayer was reduced and endothelial MLC phosphorylation was enhanced in extravascular migration of fibrosarcoma cells. Endothelial MLCK inhibitor (ML-7) blocked extravascular migration of HT1080 cells and inhibited reduction of electrical resistance of a HUVEC monolayer and enhancement of endothelial MLC phosphorylation in extravascular migration of HT1080 cells in a dose-dependent manner. Endothelial MLCK regulates fibrosarcoma cell transendothelial migration through MLC phosphorylation, leading to cytoskeletal reorganization and endothelial cell constriction, then fibrosarcoma cells migrate into extravascular tissue through the gaps between endothelial cells.

  14. Basigin can be a therapeutic target to restore the retinal vascular barrier function in the mouse model of diabetic retinopathy

    PubMed Central

    Arima, Mitsuru; Cui, Dan; Kimura, Tokuhiro; Sonoda, Koh-Hei; Ishibashi, Tatsuro; Matsuda, Satoshi; Ikeda, Eiji

    2016-01-01

    Despite the advance in medical technology, diabetic retinopathy (DR) is still an intractable disease which leads to the damage of retinal cells and finally the visual loss. Impairment of retinal vascular barrier triggered by an admixture of multiple inflammatory cytokines is a core of pathophysiology of DR. Therefore, the molecules involved commonly in multiple cytokines-induced impairment of vascular barrier would be the targets of curative treatment of DR. Here, we demonstrate that basigin, a transmembrane molecule expressed in neural barrier-forming endothelial cells, is the molecule essential for vascular barrier impairment which is shared by various triggers including VEGF, TNFα and IL-1β. In vitro data with neural microvascular endothelial cells indicated that stimulation with cytokines decreases the levels of claudin-5 in cell membranes and consequently impairs the barrier function in a manner dependent on the interaction of claudin-5 with basigin and caveolin-1. In addition, the increased vascular permeability in retinas of streptozotocin-induced diabetic mice was shown to be clearly normalized by intravitreous injection of siRNAs specific for basigin. This study has highlighted basigin as a common essential molecule for various stimuli-induced impairment of retinal vascular barrier, which can be a target for strategies to establish a curative treatment of DR. PMID:27917946

  15. Assessments of arterial stiffness and endothelial function using pulse wave analysis.

    PubMed

    Stoner, Lee; Young, Joanna M; Fryer, Simon

    2012-01-01

    Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability.

  16. MicroRNA-155 negatively affects blood-brain barrier function during neuroinflammation.

    PubMed

    Lopez-Ramirez, Miguel Alejandro; Wu, Dongsheng; Pryce, Gareth; Simpson, Julie E; Reijerkerk, Arie; King-Robson, Josh; Kay, Oliver; de Vries, Helga E; Hirst, Mark C; Sharrack, Basil; Baker, David; Male, David Kingsley; Michael, Gregory J; Romero, Ignacio Andres

    2014-06-01

    Blood-brain barrier (BBB) dysfunction is a hallmark of neurological conditions such as multiple sclerosis (MS) and stroke. However, the molecular mechanisms underlying neurovascular dysfunction during BBB breakdown remain elusive. MicroRNAs (miRNAs) have recently emerged as key regulators of pathogenic responses, although their role in central nervous system (CNS) microvascular disorders is largely unknown. We have identified miR-155 as a critical miRNA in neuroinflammation at the BBB. miR-155 is expressed at the neurovascular unit of individuals with MS and of mice with experimental autoimmune encephalomyelitis (EAE). In mice, loss of miR-155 reduced CNS extravasation of systemic tracers, both in EAE and in an acute systemic inflammation model induced by lipopolysaccharide. In cultured human brain endothelium, miR-155 was strongly and rapidly upregulated by inflammatory cytokines. miR-155 up-regulation mimicked cytokine-induced alterations in junctional organization and permeability, whereas inhibition of endogenous miR-155 partially prevented a cytokine-induced increase in permeability. Furthermore, miR-155 modulated brain endothelial barrier function by targeting not only cell-cell complex molecules such as annexin-2 and claudin-1, but also focal adhesion components such as DOCK-1 and syntenin-1. We propose that brain endothelial miR-155 is a negative regulator of BBB function that may constitute a novel therapeutic target for CNS neuroinflammatory disorders. © FASEB.

  17. Wnt activation of immortalized brain endothelial cells as a tool for generating a standardized model of the blood brain barrier in vitro.

    PubMed

    Paolinelli, Roberta; Corada, Monica; Ferrarini, Luca; Devraj, Kavi; Artus, Cédric; Czupalla, Cathrin J; Rudini, Noemi; Maddaluno, Luigi; Papa, Eleanna; Engelhardt, Britta; Couraud, Pierre Olivier; Liebner, Stefan; Dejana, Elisabetta

    2013-01-01

    Reproducing the characteristics and the functional responses of the blood-brain barrier (BBB) in vitro represents an important task for the research community, and would be a critical biotechnological breakthrough. Pharmaceutical and biotechnology industries provide strong demand for inexpensive and easy-to-handle in vitro BBB models to screen novel drug candidates. Recently, it was shown that canonical Wnt signaling is responsible for the induction of the BBB properties in the neonatal brain microvasculature in vivo. In the present study, following on from earlier observations, we have developed a novel model of the BBB in vitro that may be suitable for large scale screening assays. This model is based on immortalized endothelial cell lines derived from murine and human brain, with no need for co-culture with astrocytes. To maintain the BBB endothelial cell properties, the cell lines are cultured in the presence of Wnt3a or drugs that stabilize β-catenin, or they are infected with a transcriptionally active form of β-catenin. Upon these treatments, the cell lines maintain expression of BBB-specific markers, which results in elevated transendothelial electrical resistance and reduced cell permeability. Importantly, these properties are retained for several passages in culture, and they can be reproduced and maintained in different laboratories over time. We conclude that the brain-derived endothelial cell lines that we have investigated gain their specialized characteristics upon activation of the canonical Wnt pathway. This model may be thus suitable to test the BBB permeability to chemicals or large molecular weight proteins, transmigration of inflammatory cells, treatments with cytokines, and genetic manipulation.

  18. Wnt Activation of Immortalized Brain Endothelial Cells as a Tool for Generating a Standardized Model of the Blood Brain Barrier In Vitro

    PubMed Central

    Paolinelli, Roberta; Artus, Cédric; Czupalla, Cathrin J.; Rudini, Noemi; Maddaluno, Luigi; Papa, Eleanna; Engelhardt, Britta; Couraud, Pierre Olivier; Liebner, Stefan; Dejana, Elisabetta

    2013-01-01

    Reproducing the characteristics and the functional responses of the blood–brain barrier (BBB) in vitro represents an important task for the research community, and would be a critical biotechnological breakthrough. Pharmaceutical and biotechnology industries provide strong demand for inexpensive and easy-to-handle in vitro BBB models to screen novel drug candidates. Recently, it was shown that canonical Wnt signaling is responsible for the induction of the BBB properties in the neonatal brain microvasculature in vivo. In the present study, following on from earlier observations, we have developed a novel model of the BBB in vitro that may be suitable for large scale screening assays. This model is based on immortalized endothelial cell lines derived from murine and human brain, with no need for co-culture with astrocytes. To maintain the BBB endothelial cell properties, the cell lines are cultured in the presence of Wnt3a or drugs that stabilize β-catenin, or they are infected with a transcriptionally active form of β-catenin. Upon these treatments, the cell lines maintain expression of BBB-specific markers, which results in elevated transendothelial electrical resistance and reduced cell permeability. Importantly, these properties are retained for several passages in culture, and they can be reproduced and maintained in different laboratories over time. We conclude that the brain-derived endothelial cell lines that we have investigated gain their specialized characteristics upon activation of the canonical Wnt pathway. This model may be thus suitable to test the BBB permeability to chemicals or large molecular weight proteins, transmigration of inflammatory cells, treatments with cytokines, and genetic manipulation. PMID:23940549

  19. Endothelial Microparticle-Derived Reactive Oxygen Species: Role in Endothelial Signaling and Vascular Function

    PubMed Central

    Burger, Dylan; Turner, Maddison; Munkonda, Mercedes N.; Touyz, Rhian M.

    2016-01-01

    Endothelial microparticles are effectors of endothelial damage; however mechanisms involved are unclear. We examined the effects of eMPs on cultured endothelial cells (ECs) and isolated vessels and investigated the role of eMP-derived reactive oxygen species (ROS) and redox signaling in these processes. eMPs were isolated from EC media and their ability to directly produce ROS was assessed by lucigenin and liquid chromatography. Nicotinamide adenine dinucleotide phosphate oxidase (Nox) subunits were probed by Western blot. ECs were treated with eMPs and effects on kinase signaling, superoxide anion (O2∙−) generation, and nitric oxide (NO) production were examined. Acetylcholine-mediated vasorelaxation was assessed by myography in eMP-treated mesenteric arteries. eMPs contained Nox1, Nox2, Nox4, p47phox, p67phox, and p22phox and they produced ROS which was inhibited by the Nox inhibitor, apocynin. eMPs increased phosphorylation of ERK1/2 and Src, increased O2∙− production, and decreased A23187-induced NO production in ECs. Pretreatment of eMPs with apocynin diminished eMP-mediated effects on ROS and NO production but had no effect on eMP-mediated kinase activation or impairment in vasorelaxation. Our findings identify a novel mechanism whereby eMP-derived ROS contributes to MP bioactivity. These interactions may be important in conditions associated with vascular injury and increased eMP formation. PMID:27313830

  20. The endothelial protein C receptor and malaria.

    PubMed

    van der Poll, Tom

    2013-08-01

    In this issue of Blood, Moxon et al provide novel insight into the pathogenesis of cerebral malaria, linking loss of the endothelial protein C receptor (EPCR) on brain vessels, caused by cytoadherent infected erythrocytes, with localized coagulation, inflammation, and disruption of endothelial barrier function.

  1. Modulation of vascular endothelial cell function by palm oil antioxidants.

    PubMed

    Abeywardena, M Y; Head, R J; Gapor, A

    1997-03-01

    Several cardiovascular risk factors including, hypercholesterolaemia and hypertension, lead to diseased blood vessels due to endothelial cell dysfunction. Recent studies also indicate that such alterations in blood vessel function may involve free radical related mechanism(s). Therefore, in the present study, two different preparations of palm oils with variable antioxidant profiles, as well as a purified antioxidant fraction extracted from unprocessed palm oil (tocotrienol-rich-factor; TRF), were tested for their ability to influence blood vessel dysfunction in the spontaneously hypertensive rat (SHR). Adult SHRs were fed a synthetic diet supplemented (5% w/w) with either physically refined palm oil (PO), golden palm cooking oil (Nutrolein; GPO) or olive oil (OO; control diet). Antioxidant rich diet (TRF diet) was prepared by supplementing the OO diet with 0.2% (w/w) TRF. After 12 weeks of pre-feeding, segments of thoracic aorta were used to evaluate vascular function. Compared to the normotensive Wistar-Kyoto (WKY) control rats, aortic rings from the SHR showed impaired endothelium dependent relaxation to acetylcholine (ACh) which was restored by dietary TRF (p<0.05, ANOVA and Tukey's test). In addition, the paradoxical increase in tension in control hypertensive vessels observed at higher doses of ACh was prevented by TRF and also by the PO and GPO diets. Although the development of thromboxane-like constrictor response, after the inhibition of nitric oxide in hypertensive vessels, was unaffected by test diets, both TRF and GPO feeding prevented the amplification of this unwanted constriction by a threshold dose (7.2x10-10 M) of noradrenaline. Results suggest a modulatory role for minor constituents of edible oils and are in agreement with the recently reported benefits of natural antioxidants against cardiovascular diseases.

  2. Isolation, Characterization, and Functional Analysis of Ferret Lymphatic Endothelial Cells

    PubMed Central

    Berendam, Stella J.; Fallert-Junecko, Beth A.; Murphy-Corb, Michael A.; Fuller, Deborah H.; Reinhart, Todd A.

    2014-01-01

    The lymphatic endothelium (LE) serves as a conduit for transport of immune cells and soluble antigens from peripheral tissues to draining lymph nodes (LNs), contributing to development of host immune responses and possibly dissemination of microbes. Lymphatic endothelial cells (LECs) are major constituents of the lymphatic endothelium. These specialized cells could play important roles in initiation of host innate immune responses through sensing of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs), including toll-like receptors (TLRs). LECs secrete pro-inflammatory cytokines and chemokines to create local inflammatory conditions for recruitment of naïve antigen presenting cells (APCs) such as dendritic cells (DCs) to sites of infection and/or vaccine administration. In this study, we examined the innate immune potential of primary LEC populations derived from multiple tissues of an animal model for human infectious diseases -- the ferret. We generated a total of six primary LEC populations from lung, tracheal, and mesenteric LN tissues from three different ferrets. Standard RT-PCR characterization of these primary LECs showed that they varied in their expression of LEC markers. The ferret LECs were examined for their ability to respond to poly I:C (TLR3 and RIG-1 ligand) and other known TLR ligands as measured by production of proinflammatory cytokine (IFNα, IL6, IL10, Mx1, and TNFα) and chemokine (CCL5, CCL20, and CXCL10) mRNAs using real time RT-PCR. Poly I:C exposure induced robust proinflammatory responses by all of the primary ferret LECs. Chemotaxis was performed to determine the functional activity of CCL20 produced by the primary lung LECs and showed that the LEC-derived CCL20 was abundant and functional. Taken together, our results continue to reveal the innate immune potential of primary LECs during pathogen-host interactions and expand our understanding of the roles of LECs might play in health and disease in

  3. Irisin improves endothelial function in obese mice through the AMPK-eNOS pathway.

    PubMed

    Han, Fang; Zhang, Shuxian; Hou, Ningning; Wang, Di; Sun, Xiaodong

    2015-11-01

    Irisin is a novel hormone secreted by myocytes. Lower levels of irisin are independently associated with endothelial dysfunction in obese subjects. The objective of this study was to explore whether irisin exerts a direct vascular protective effect on endothelial function in high-fat-diet-induced obese mice. Male C57BL/6 mice were given chow or a high-fat diet with or without treatment with irisin. Aortic endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV). Nitric oxide (NO) in the aorta was determined. The effect of irisin on the levels of AMP-activated protein kinase (AMPK), Akt, and endothelial NO synthase (eNOS) phosphorylation in endothelial cells was determined. Human umbilical vein endothelial cells were used to study the role of irisin in the AMPK-eNOS pathway. Acetylcholine-stimulated EDV was significantly lower in obese mice compared with control mice. Treatment of obese mice with irisin significantly enhanced EDV and improved endothelial function. This beneficial effect of irisin was partly attenuated in the presence of inhibitors of AMPK, Akt, and eNOS. Treatment of obese mice with irisin enhanced NO production and phosphorylation of AMPK, Akt, and eNOS in endothelial cells. These factors were also enhanced by irisin in human umbilical vein endothelial cells in vitro. Suppression of AMPK expression by small interfering RNA blocked irisin-induced eNOS and Akt phosphorylation and NO production. We have provided the first evidence that irisin improves endothelial function in aortas of high-fat-diet-induced obese mice. The mechanism for this protective effect is related to the activation of the AMPK-eNOS signaling pathway.

  4. BASIS FOR ENHANCED BARRIER FUNCTION OF PIGMENTED SKIN

    PubMed Central

    Man, Mao-Qiang; Lin, Tzu-Kai; Santiago, Juan Luis; Celli, Anna; Zhong, Lily; Huang, Zhi-Ming; Roelandt, Truus; Hupe, Melanie; Sundberg, John P.; Silva, Kathleen A.; Crumrine, Debra; Martin-Ezquerra, Gemma; Trullas, Carles; Sun, Richard; Wakefield, Joan S.; Wei, Maria L.; Feingold, Kenneth R.; Mauro, Theodora M.; Elias, Peter M.

    2014-01-01

    Humans with darkly-pigmented skin display superior permeability barrier function in comparison to humans with lightly-pigmented skin. The reduced pH of the stratum corneum (SC) of darkly-pigmented skin could account for enhanced function, because acidifying lightly-pigmented human SC resets barrier function to darkly-pigmented levels. In SKH1 (non-pigmented) vs. SKH2/J (pigmented) hairless mice, we evaluated how a pigment-dependent reduction in pH could influence epidermal barrier function. Permeability barrier homeostasis is enhanced in SKH2/J vs. SKH1 mice, correlating with a reduced pH in the lower SC that co-localizes with the extrusion of melanin granules. Darkly-pigmented human epidermis also shows substantial melanin extrusion in the outer epidermis. Both acute barrier disruption and topical basic pH challenges accelerate re-acidification of SKH2/J (but not SKH1) SC, while inducing melanin extrusion. SKH2/J mice also display enhanced expression of the SC acidifying enzyme, secretory phospholipase A2f (sPLA2f). Enhanced barrier function of SKH2/J mice could be attributed to enhanced activity of two acidic pH-dependent, ceramide-generating enzymes, β-glucocerebrosidase and acidic sphingomyelinase, leading to accelerated maturation of SC lamellar bilayers. Finally, organotypic cultures of darkly-pigmented-bearing human keratinocytes display enhanced barrier function in comparison to lightly-pigmented cultures. Together, these results suggest that the superior barrier function of pigmented epidermis can be largely attributed to the pH-lowering impact of melanin persistence/extrusion and enhanced sPLA2f expression. PMID:24732399

  5. Basis for enhanced barrier function of pigmented skin.

    PubMed

    Man, Mao-Qiang; Lin, Tzu-Kai; Santiago, Juan L; Celli, Anna; Zhong, Lily; Huang, Zhi-Ming; Roelandt, Truus; Hupe, Melanie; Sundberg, John P; Silva, Kathleen A; Crumrine, Debra; Martin-Ezquerra, Gemma; Trullas, Carles; Sun, Richard; Wakefield, Joan S; Wei, Maria L; Feingold, Kenneth R; Mauro, Theodora M; Elias, Peter M

    2014-09-01

    Humans with darkly pigmented skin display superior permeability barrier function in comparison with humans with lightly pigmented skin. The reduced pH of the stratum corneum (SC) of darkly pigmented skin could account for enhanced function, because acidifying lightly pigmented human SC resets barrier function to darkly pigmented levels. In SKH1 (nonpigmented) versus SKH2/J (pigmented) hairless mice, we evaluated how a pigment-dependent reduction in pH could influence epidermal barrier function. Permeability barrier homeostasis is enhanced in SKH2/J versus SKH1 mice, correlating with a reduced pH in the lower SC that colocalizes with the extrusion of melanin granules. Darkly pigmented human epidermis also shows substantial melanin extrusion in the outer epidermis. Both acute barrier disruption and topical basic pH challenges accelerate reacidification of SKH2/J (but not SKH1) SC, while inducing melanin extrusion. SKH2/J mice also display enhanced expression of the SC acidifying enzyme, secretory phospholipase A2f (sPLA2f). Enhanced barrier function of SKH2/J mice could be attributed to enhanced activity of two acidic pH-dependent, ceramide-generating enzymes, β-glucocerebrosidase and acidic sphingomyelinase, leading to accelerated maturation of SC lamellar bilayers. Finally, organotypic cultures of darkly pigmented human keratinocytes display enhanced barrier function in comparison with lightly pigmented cultures. Together, these results suggest that the superior barrier function of pigmented epidermis can be largely attributed to the pH-lowering impact of melanin persistence/extrusion and enhanced sPLA2f expression.

  6. Structure and function of the epidermis related to barrier properties.

    PubMed

    Baroni, Adone; Buommino, Elisabetta; De Gregorio, Vincenza; Ruocco, Eleonora; Ruocco, Vincenzo; Wolf, Ronni

    2012-01-01

    The most important function of the skin is the formation of a barrier between the "inside" and the "outside" of the organism, which prevents invasion of pathogens and fends off chemical assaults as well as the unregulated loss of water and solutes. The physical barrier is mainly localized in the stratum corneum, which consists of protein-enriched cells and lipid-enriched intercellular domains. Any modifications in epidermal differentiation and lipid composition results in altered barrier function, a central event in various skin alterations and diseases. This contribution presents a brief description of the structure of the skin, paying attention to the most important components responsible for skin barrier function. Copyright © 2012. Published by Elsevier Inc.

  7. Primary porcine brain microvascular endothelial cells: biochemical and functional characterisation as a model for drug transport and targeting.

    PubMed

    Smith, Mathew; Omidi, Yadollah; Gumbleton, Mark

    2007-05-01

    The blood-brain barrier (BBB) remains a significant obstacle to the delivery of therapeutic agents into the central nervous system (CNS). Primary cell cultures of brain capillary endothelial cells represent the closest possible phenotype to the in vivo BBB cell providing a convenient model for the study of transport systems and events that mediate solute delivery to the CNS. In this investigation we have characterized an in vitro primary BBB model from porcine brain microvascular endothelial capillary (PBMVEC) cells after recovery from cryopreservation of upto 12 months and studied their modulation by astrocytes. Co-cultures of PBMVECs with astrocytes (C6 astroglioma) resulted in trans-endothelial electrical resistance of up to approximately 900Omega cm2 and marked discrimination between the para- and trans- cellular markers sucrose and propranolol. Micrographs of confluent monolayers of PBMVECs showed the presence of tight junction complexes and vesicles with the morphological characteristics of either caveolae or clathrin coated pits. Extensive RT-PCR evaluation highlighted the expression of tight junction transcripts, ABC transporters, leptin receptor and select nutrient transporters. Functional studies examined the kinetics of transport of glucose, large neutral amino acids and p-glycoprotein (P-gp). Our findings indicate primary PBMVECs retain many barrier characteristics and transport pathways of the in vivo BBB. Further, primary cells can be stored as frozen stocks which can be thawed and cultured without phenotypic drift many months after isolation. Frozen PBMVECs therefore serve as a robust and convenient in vitro cell culture tool for research programs involving CNS drug delivery and targeting and in studies addressing blood-brain barrier transport mechanisms.

  8. Sphingosine 1-phosphate (S1P) carrier-dependent regulation of endothelial barrier: high density lipoprotein (HDL)-S1P prolongs endothelial barrier enhancement as compared with albumin-S1P via effects on levels, trafficking, and signaling of S1P1.

    PubMed

    Wilkerson, Brent A; Grass, G Daniel; Wing, Shane B; Argraves, W Scott; Argraves, Kelley M

    2012-12-28

    Sphingosine 1-phosphate (S1P) is a blood-borne lysosphingolipid that acts to promote endothelial cell (EC) barrier function. In plasma, S1P is associated with both high density lipoproteins (HDL) and albumin, but it is not known whether the carriers impart different effects on S1P signaling. Here we establish that HDL-S1P sustains EC barrier longer than albumin-S1P. We showed that the sustained barrier effects of HDL-S1P are dependent on signaling by the S1P receptor, S1P1, and involve persistent activation of Akt and endothelial NOS (eNOS), as well as activity of the downstream NO target, soluble guanylate cyclase (sGC). Total S1P1 protein levels were found to be higher in response to HDL-S1P treatment as compared with albumin-S1P, and this effect was not associated with increased S1P1 mRNA or dependent on de novo protein synthesis. Several pieces of evidence indicate that long term EC barrier enhancement activity of HDL-S1P is due to specific effects on S1P1 trafficking. First, the rate of S1P1 degradation, which is proteasome-mediated, was slower in HDL-S1P-treated cells as compared with cells treated with albumin-S1P. Second, the long term barrier-promoting effects of HDL-S1P were abrogated by treatment with the recycling blocker, monensin. Finally, cell surface levels of S1P1 and levels of S1P1 in caveolin-enriched microdomains were higher after treatment with HDL-S1P as compared with albumin-S1P. Together, the findings reveal S1P carrier-specific effects on S1P1 and point to HDL as the physiological mediator of sustained S1P1-PI3K-Akt-eNOS-sGC-dependent EC barrier function.

  9. Brain barriers: Crosstalk between complex tight junctions and adherens junctions.

    PubMed

    Tietz, Silvia; Engelhardt, Britta

    2015-05-25

    Unique intercellular junctional complexes between the central nervous system (CNS) microvascular endothelial cells and the choroid plexus epithelial cells form the endothelial blood-brain barrier (BBB) and the epithelial blood-cerebrospinal fluid barrier (BCSFB), respectively. These barriers inhibit paracellular diffusion, thereby protecting the CNS from fluctuations in the blood. Studies of brain barrier integrity during development, normal physiology, and disease have focused on BBB and BCSFB tight junctions but not the corresponding endothelial and epithelial adherens junctions. The crosstalk between adherens junctions and tight junctions in maintaining barrier integrity is an understudied area that may represent a promising target for influencing brain barrier function. © 2015 Tietz and Engelhardt.

  10. In vitro assessment of alkylglyceryl-functionalized chitosan nanoparticles as permeating vectors for the blood-brain barrier.

    PubMed

    Lien, Chun-Fu; Molnár, Eva; Toman, Petr; Tsibouklis, John; Pilkington, Geoffrey J; Górecki, Dariusz C; Barbu, Eugen

    2012-04-09

    A series of O-substituted alkylglyceryl chitosans with systematically varied alkyl chain length and degree of grafting has been employed for the formulation of aqueous nanoparticulate systems, which were in turn investigated for their effects on a modeled blood-brain-barrier system of mouse-brain endothelial cells. Barrier function measurements employing electric cell-substrate impedance sensing and analyses of tight junction-specific protein profiles have indicated that the alkylglyceryl-modified chitosan nanoparticles impact upon the integrity of the model blood-brain barrier, whereas confocal microscopy experiments have demonstrated the efficient cellular uptake and the perinuclear localization of these nanoparticles. The application of nanoparticles to the model blood-brain barrier effected an increase in its permeability, as demonstrated by following the transport of the tracer molecule fluorescein isothiocyanate.

  11. Mechanisms and regulation of iron trafficking across the capillary endothelial cells of the blood-brain barrier

    PubMed Central

    McCarthy, Ryan C.; Kosman, Daniel J.

    2015-01-01

    The transcellular trafficking of iron from the blood into the brain interstitium depends on iron uptake proteins in the apical membrane of brain microvascular capillary endothelial cells and efflux proteins at the basolateral, abluminal membrane. In this review, we discuss the three mechanisms by which these cells take-up iron from the blood and the sole mechanism by which they efflux this iron into the abluminal space. We then focus on the regulation of this efflux pathway by exocrine factors that are released from neighboring astrocytes. Also discussed are the cytokines secreted by capillary cells that regulate the expression of these glial cell signals. Among the interstitial factors that regulate iron efflux into the brain is the Amyloid precursor protein (APP). The role of this amyliodogenic species in brain iron metabolism is discussed. Last, we speculate on the potential relationship between iron transport at the blood-brain barrier and neurological disorders associated with iron mismanagement. PMID:26236187

  12. Glyoxalase 1-knockdown in human aortic endothelial cells – effect on the proteome and endothelial function estimates

    PubMed Central

    Stratmann, Bernd; Engelbrecht, Britta; Espelage, Britta C.; Klusmeier, Nadine; Tiemann, Janina; Gawlowski, Thomas; Mattern, Yvonne; Eisenacher, Martin; Meyer, Helmut E.; Rabbani, Naila; Thornalley, Paul J.; Tschoepe, Diethelm; Poschmann, Gereon; Stühler, Kai

    2016-01-01

    Methylglyoxal (MG), an arginine-directed glycating agent, is implicated in diabetic late complications. MG is detoxified by glyoxalase 1 (GLO1) of the cytosolic glyoxalase system. The aim was to investigate the effects of MG accumulation by GLO1-knockdown under hyperglycaemic conditions in human aortic endothelial cells (HAECs) hypothesizing that the accumulation of MG accounts for the deleterious effects on vascular function. SiRNA-mediated knockdown of GLO1 was performed and MG concentrations were determined. The impact of MG on the cell proteome and targets of MG glycation was analysed, and confirmed by Western blotting. Markers of endothelial function and apoptosis were assessed. Collagen content was assayed in cell culture supernatant. GLO1-knockdown increased MG concentration in cells and culture medium. This was associated with a differential abundance of cytoskeleton stabilisation proteins, intermediate filaments and proteins involved in posttranslational modification of collagen. An increase in fibrillar collagens 1 and 5 was detected. The extracellular concentration of endothelin-1 was increased following GLO1-knockdown, whereas the phosphorylation and amount of eNOS was not influenced by GLO1-knockdown. The expression of ICAM-1, VCAM-1 and of MCP-1 was elevated and apoptosis was increased. MG accumulation by GLO1-knockdown provoked collagen expression, endothelial inflammation and dysfunction and apoptosis which might contribute to vascular damage. PMID:27898103

  13. Development of a direct contact astrocyte-human cerebral microvessel endothelial cells blood-brain barrier coculture model.

    PubMed

    Kulczar, Chris; Lubin, Kelsey E; Lefebvre, Sylvia; Miller, Donald W; Knipp, Gregory T

    2017-09-05

    In conventional in-vitro blood-brain barrier (BBB) models, primary and immortalized brain microvessel endothelial cell (BMEC) lines are often cultured in a monolayer or indirect coculture or triculture configurations with astrocytes or pericytes, for screening permeation of therapeutic or potentially neurotoxic compounds. In each of these cases, the physiological relevancy associated with the direct contact between the BMECs, pericytes and astrocytes that form the BBB and resulting synergistic interactions are lost. We look to overcome this limitation with a direct contact coculture model. We established and optimized a direct interaction coculture system where primary human astrocytes are cultured on the apical surface of a Transwell® filter support and then human cerebral microvessel endothelial cells (hCMEC/D3) seeded directly on the astrocyte lawn. The studies suggest the direct coculture model may provide a more restrictive and physiologically relevant model through a significant reduction in paracellular transport of model compounds in comparison with monoculture and indirect coculture. In comparison with existing methods, the indirect coculture and monoculture models utilized may limit cell-cell signaling between human astrocytes and BMECs that are possible with direct configurations. Paracellular permeability reductions with the direct coculture system may enhance therapeutic agent and potential neurotoxicant screening for BBB permeability better than the currently available monoculture and indirect coculture in-vitro models. © 2017 Royal Pharmaceutical Society.

  14. The role of non-endothelial cells on the penetration of nanoparticles through the blood brain barrier.

    PubMed

    Moura, Rui Pedro; Almeida, Andreia; Sarmento, Bruno

    2017-09-09

    The blood brain barrier (BBB) is a well-established cell-based membrane that circumvents the central nervous system (CNS), protecting it from harmful substances. Due to its robustness and cell integrity, it is also an outstanding opponent when it comes to the delivery of several therapeutic agents to the brain, which requires the crossing through its highly-organized structure. This regulation and cell-cell communications occur mostly between astrocytes, pericytes and endothelial cells. Therefore, alternative ways to deliver drugs to the CNS, overcoming the BBB are required, to improve the efficacy of brain target drugs. Nanoparticles emerge here as a promising drug delivery strategy, due to their ability of high drug loading and the capability to exploit specific delivery pathways that most drugs are unable to when administered freely, increasing their bioavailability in the CNS. Thus, further attempts to assess the possible influence of non-endothelial may have on the BBB translocation of nanoparticles are here revised. Furthermore, the use of macrophages and/or monocytes as nanoparticle delivery cells are also approached. Lastly, the temporarily disruption of the overall organization and normal structure of the BBB to promote the penetration of nanoparticles aimed at the CNS is described, as a synergistic path. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Endothelial function and cardiovascular risk stratification in menopausal women.

    PubMed

    Mulvagh, S L; Behrenbeck, T; Lahr, B A; Bailey, K R; Zais, T G; Araoz, P A; Miller, V M

    2010-02-01

    Peripheral arterial, endothelium-dependent, flow-mediated reactive hyperemia is reduced in individuals with atherosclerosis. This study tested the hypothesis that digital tonometry, as a surrogate of endothelial function, is useful to stratify cardiovascular risk in recently menopausal women who are asymptomatic for cardiovascular disease. Women undergoing screening for the Kronos Early Estrogen Prevention Study (KEEPS) were evaluated for conventional risk factors, flow-mediated reactive hyperemia by digital tonometry (RHI), carotid intima-media thickness (CIMT) by ultrasound, and coronary arterial calcium (CAC) by 64-slice CT scanner. One hundred and two non-diabetic Caucasian women (53.0 +/- 2.3 years old, 18.0 +/- 9.0 months past their last menses) participated; 72% were never-smokers. Fourteen women had positive CAC scores (range 0.5-133 Agatston units); CIMT ranged from 0.57 to 1.06 mm. RHI ranged from 1.26 to 5.44. RHI did not correlate with time past menopause, CAC, CIMT, total cholesterol or low density lipoprotein cholesterol. The significant negative correlation of RHI with body mass index (r = -0.21, p = 0.031) was lost in non-smokers (r = - 0.17, p = 0.14). There was also a negative correlation of high density lipoprotein cholesterol with CAC, both in the overall group and non-smokers (rho = -0.20, p = 0.05 and rho = -0.27, p = 0.02, respectively). RHI varies widely in healthy women within the first 3 years of menopause. RHI was not associated with standard risk assessment algorithms, CAC or CIMT. RHI may indicate an additional, independent component and non-invasive tool to further stratify cardiovascular risk in recently menopausal women. As KEEPS continues, data on RHI will provide information regarding hormonal therapy, endovascular biology and atherosclerotic risk.

  16. Vascular Endothelial Growth Factor Modulates Skeletal Myoblast Function

    PubMed Central

    Germani, Antonia; Di Carlo, Anna; Mangoni, Antonella; Straino, Stefania; Giacinti, Cristina; Turrini, Paolo; Biglioli, Paolo; Capogrossi, Maurizio C.

    2003-01-01

    Vascular endothelial growth factor (VEGF) expression is enhanced in ischemic skeletal muscle and is thought to play a key role in the angiogenic response to ischemia. However, it is still unknown whether, in addition to new blood vessel growth, VEGF modulates skeletal muscle cell function. In the present study immunohistochemical analysis showed that, in normoperfused mouse hindlimb, VEGF and its receptors Flk-1 and Flt-1 were expressed mostly in quiescent satellite cells. Unilateral hindlimb ischemia was induced by left femoral artery ligation. At day 3 and day 7 after the induction of ischemia, Flk-1 and Flt-1 were expressed in regenerating muscle fibers and VEGF expression by these fibers was markedly enhanced. Additional in vitro experiments showed that in growing medium both cultured satellite cells and myoblast cell line C2C12 expressed VEGF and its receptors. Under these conditions, Flk-1 receptor exhibited constitutive tyrosine phosphorylation that was increased by VEGF treatment. During myogenic differentiation Flk-1 and Flt-1 were down-regulated. In a modified Boyden Chamber assay, VEGF enhanced C2C12 myoblasts migration approximately fivefold. Moreover, VEGF administration to differentiating C2C12 myoblasts prevented apoptosis, while inhibition of VEGF signaling either with selective VEGF receptor inhibitors (SU1498 and CB676475) or a neutralizing Flk-1 antibody, enhanced cell death approximately 3.5-fold. Finally, adenovirus-mediated VEGF165 gene transfer inhibited ischemia-induced apoptosis in skeletal muscle. These results support a role for VEGF in myoblast migration and survival, and suggest a novel autocrine role of VEGF in skeletal muscle repair during ischemia. PMID:14507649

  17. Inhibition of matrix metalloproteinase-2 improves endothelial function and prevents hypertension in insulin-resistant rats

    PubMed Central

    Nagareddy, PR; Rajput, PS; Vasudevan, H; McClure, B; Kumar, U; MacLeod, KM; McNeill, JH

    2012-01-01

    BACKGROUND AND PURPOSE Insulin resistance is often found to be associated with high blood pressure. We propose that in insulin-resistant hypertension, endothelial dysfunction is the consequence of increased activity of vascular MMP-2. As MMP-2 proteolytically cleaves a number of extracellular matrix proteins, we hypothesized that MMP-2 impairs endothelial function by proteolytic degradation of endothelial NOS (eNOS) or its cofactor, heat shock protein 90 (HSP90). EXPERIMENTAL APPROACH We tested our hypothesis in bovine coronary artery endothelial cells and fructose-fed hypertensive rats (FHR), a model of acquired systolic hypertension and insulin resistance. KEY RESULTS Treatment of FHRs with the MMP inhibitor doxycycline, preserved endothelial function as well as prevented the development of hypertension, suggesting that MMPs impair endothelial function. Furthermore, incubating endothelial cells in vitro with a recombinant MMP-2 decreased NO production in a dose-dependent manner. Using substrate cleavage assays and immunofluorescence microscopy studies, we found that MMP-2 not only cleaves and degrades HSP90, an eNOS cofactor but also co-localizes with both eNOS and HSP90 in endothelial cells, suggesting that MMPs functionally interact with the eNOS system. Treatment of FHRs with doxycycline attenuated the decrease in eNOS and HSP90 expression but did not improve insulin sensitivity. CONCLUSIONS AND IMPLICATIONS Our data suggest that increased activity of MMP-2 in FHRs impairs endothelial function and promotes hypertension. Inhibition of MMP-2 could be a potential therapeutic strategy for the management of hypertension. PMID:21740410

  18. Integrated Microfluidic Platform with Multiple Functions To Probe Tumor-Endothelial Cell Interaction.

    PubMed

    Lin, Ling; Lin, Xuexia; Lin, Luyao; Feng, Qiang; Kitamori, Takehiko; Lin, Jin-Ming; Sun, Jiashu

    2017-09-19

    Interaction between tumor and endothelial cells could affect tumor growth and progression and induce drug resistance during cancer therapy. Investigation of tumor-endothelial cell interaction involves cell coculture, protein detection, and analysis of drug metabolites, which are complicated and time-consuming. In this work, we present an integrated microfluidic device with three individual components (cell coculture component, protein detection component, and pretreatment component for drug metabolites) to probe the interaction between tumor and endothelial cells. Cocultured cervical carcinoma cells (CaSki cells) and human umbilical vein endothelial cells (HUVECs) show higher resistance to chemotherapeutic agents than single-cultured cells, indicated by higher cell viability, increased expression of angiogenic proteins, and elevated level of paclitaxel metabolites under coculture conditions. This integrated microfluidic platform with multiple functions facilitates understanding of the interaction between tumor and endothelial cells, and it may become a promising tool for drug screening within an engineered tumor microenvironment.

  19. Mechanism of action of collagenase on the blood-brain barrier permeability. Increase of endothelial cell pinocytotic activity as shown with horse-radish peroxidase as a tracer.

    PubMed

    Godeau, G; Robert, A M

    1979-12-01

    The ultrastructural mechanism of the protease induced blood-brain barrier permeability-increase was studied with horse-radish peroxidase as a tracer. After intravenous injection of collagenase or pronase, a significantly increased number of pinocytotic vesicles was found in brain capillary endothelial cells. alpha-Chymotrypsine did not exert such an action.

  20. PDCD10 (CCM3) regulates brain endothelial barrier integrity in cerebral cavernous malformation type 3: role of CCM3-ERK1/2-cortactin cross-talk.

    PubMed

    Stamatovic, Svetlana M; Sladojevic, Nikola; Keep, Richard F; Andjelkovic, Anuska V

    2015-11-01

    Impairment of brain endothelial barrier integrity is critical for cerebral cavernous malformation (CCM) lesion development. The current study investigates changes in tight junction (TJ) complex organization when PDCD10 (CCM3) is mutated/depleted in human brain endothelial cells. Analysis of lesions with CCM3 mutation and brain endothelial cells transfected with CCM3 siRNA (CCM3-knockdown) showed little or no increase in TJ transmembrane and scaffolding proteins mRNA expression, but proteins levels were generally decreased. CCM3-knockdown cells had a redistribution of claudin-5 and occludin from the membrane to the cytosol with no alterations in protein turnover but with diminished protein-protein interactions with ZO-1 and ZO-1 interaction with the actin cytoskeleton. The most profound effect of CCM3 mutation/depletion was on an actin-binding protein, cortactin. CCM3 depletion caused cortactin Ser-phosphorylation, dissociation from ZO-1 and actin, redistribution to the cytosol and degradation. This affected cortical actin ring organization, TJ complex stability and consequently barrier integrity, with constant hyperpermeability to inulin. A potential link between CCM3 depletion and altered cortactin was tonic activation of MAP kinase ERK1/2. ERK1/2 inhibition increased cortactin expression and incorporation into the TJ complex and improved barrier integrity. This study highlights the potential role of CCM3 in regulating TJ complex organization and brain endothelial barrier permeability.

  1. PDCD10 (CCM3) REGULATES BRAIN ENDOTHELIAL BARRIER INTEGRITY IN CEREBRAL CAVERNOUS MALFORMATION TYPE 3: ROLE OF CCM3-ERK1/2-CORTACTIN CROSS-TALK

    PubMed Central

    Stamatovic, Svetlana M.; Sladojevic, Nikola; Keep, Richard F.; Andjelkovic, Anuska V.

    2015-01-01

    Impairment of brain endothelial barrier integrity is critical for cerebral cavernous malformation (CCM) lesion development. The current study investigates changes in tight junction (TJ) complex organization when PDCD10 (CCM3) is mutated/depleted in human brain endothelial cells. Analysis of lesions with CCM3 mutation and brain endothelial cells transfected with CCM3 siRNA (CCM3-knockdown) showed little or no increase in TJ transmembrane and scaffolding proteins mRNA expression, but proteins levels were generally decreased. CCM3- knockdown cells had a redistribution of claudin-5 and occludin from the membrane to the cytosol with no alterations in protein turnover but with diminished protein-protein interactions with ZO-1 and ZO-1 interaction with the actin cytoskeleton. The most profound effect of CCM3 mutation/depletion was on an actin-binding protein, cortactin. CCM3 depletion caused cortactin Ser-phosphorylation, dissociation from ZO-1 and actin, redistribution to the cytosol and degradation. This affected cortical actin ring organization, TJ complex stability and consequently barrier integrity, with constant hyperpermeability to inulin. A potential link between CCM3 depletion and altered cortactin was tonic activation of MAP kinase ERK1/2. ERK1/2 inhibition increased cortactin expression and incorporation into the TJ complex and improved barrier integrity. This study highlights the potential role of CCM3 in regulating TJ complex organization and brain endothelial barrier permeability. PMID:26385474

  2. Functional Imaging of Working Memory and Peripheral Endothelial Function in Middle-Aged Adults

    PubMed Central

    Gonzales, Mitzi M.; Tarumi, Takashi; Tanaka, Hirofumi; Sugawara, Jun; Swann-Sternberg, Tali; Goudarzi, Katyoon; Haley, Andreana P.

    2010-01-01

    The current study examined the relationship between a prognostic indicator of vascular health, flow-mediated dilation (FMD), and working memory-related brain activation in healthy middle-aged adults. Forty-two participants underwent functional magnetic resonance imaging while completing a 2-Back working memory task. Brachial artery endothelial-dependent flow-mediated dilation (FMD) was assessed using B-mode ultrasound. The relationship between FMD and task-related brain activation in a priori regions of interest was modeled using hierarchical linear regression. Brachial FMD, was significantly related to reduced working memory-related activation in the right superior parietal lobule (β=0.338, p=0.027), independent of age, sex, systolic blood pressure, and full scale IQ (F(5,36)=2.66, p=0.038). These data provide preliminary support for the association between a preclinical marker of endothelial dysfunction and cerebral hemodynamic alterations in healthy middle-aged adults. Considering the modifiable nature of endothelial function, additional investigations on the prognostic significance of FMD on future cognitive impairment are warranted. PMID:20493622

  3. Molecular and functional characterization of riboflavin specific transport system in rat brain capillary endothelial cells

    PubMed Central

    Patel, Mitesh; Vadlapatla, Ramya Krishna; Pal, Dhananjay; Mitra, Ashim K.

    2012-01-01

    Riboflavin is an important water soluble vitamin (B2) required for metabolic reactions, normal cellular growth, differentiation and function. Mammalian brain cells cannot synthesize riboflavin and must import from systemic circulation. However, the uptake mechanism, cellular translocation and intracellular trafficking of riboflavin in brain capillary endothelial cells are poorly understood. The primary objective of this study is to investigate the existence of riboflavin-specific transport system and delineate the uptake and intracellular regulation of riboflavin in immortalized rat brain capillary endothelial cells (RBE4). The uptake of [3H]-Riboflavin is sodium, temperature and energy dependent but pH independent. [3H]-Riboflavin uptake is saturable with Km and Vmax values of 19 ± 3 µM and 0.235 ± 0.012 picomoles/min/mg protein, respectively. The uptake process is inhibited by unlabelled structural analogs (lumiflavin, lumichrome) but not by structurally unrelated vitamins. Ca++/calmodulin and protein kinase A (PKA) pathways are found to play an important role in the intracellular regulation of [3H]-Riboflavin. Apical and baso-lateral uptake of [3H]-Riboflavin clearly indicate that riboflavin specific transport system is predominantly localized on the apical side of RBE4 cells. A 628 bp band corresponding to riboflavin transporter is revealed in RT-PCR analysis. These findings, for the first time report the existence of a specialized and high affinity transport system for riboflavin in RBE4 cells. Blood-brain barrier (BBB) is a major obstacle limiting drug transport inside the brain as it regulates drug permeation from systemic circulation. This transporter can be utilized for targeted delivery in enhancing brain permeation of highly potent drugs on systemic administration. PMID:22683359

  4. Evaluation of the Effects of Different Energy Drinks and Coffee on Endothelial Function.

    PubMed

    Molnar, Janos; Somberg, John C

    2015-11-01

    Endothelial function plays an important role in circulatory physiology. There has been differing reports on the effect of energy drink on endothelial function. We set out to evaluate the effect of 3 energy drinks and coffee on endothelial function. Endothelial function was evaluated in healthy volunteers using a device that uses digital peripheral arterial tonometry measuring endothelial function as the reactive hyperemia index (RHI). Six volunteers (25 ± 7 years) received energy drink in a random order at least 2 days apart. Drinks studied were 250 ml "Red Bull" containing 80 mg caffeine, 57 ml "5-hour Energy" containing 230 mg caffeine, and a can of 355 ml "NOS" energy drink containing 120 mg caffeine. Sixteen volunteers (25 ± 5 years) received a cup of 473 ml coffee containing 240 mg caffeine. Studies were performed before drink (baseline) at 1.5 and 4 hours after drink. Two of the energy drinks (Red Bull and 5-hour Energy) significantly improved endothelial function at 4 hours after drink, whereas 1 energy drink (NOS) and coffee did not change endothelial function significantly. RHI increased by 82 ± 129% (p = 0.028) and 63 ± 37% (p = 0.027) after 5-hour Energy and Red Bull, respectively. The RHI changed after NOS by 2 ± 30% (p = 1.000) and by 7 ± 30% (p = 1.000) after coffee. In conclusion, some energy drinks appear to significantly improve endothelial function. Caffeine does not appear to be the component responsible for these differences. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Globular adiponectin improves high glucose-suppressed endothelial progenitor cell function through endothelial nitric oxide synthase dependent mechanisms.

    PubMed

    Huang, Po-Hsun; Chen, Jia-Shiong; Tsai, Hsiao-Ya; Chen, Yung-Hsiang; Lin, Feng-Yen; Leu, Hsin-Bang; Wu, Tao-Cheng; Lin, Shing-Jong; Chen, Jaw-Wen

    2011-07-01

    Plasma levels of adiponectin, an adipose-specific protein with putative anti-atherogenic properties, could be down-regulated in obese and diabetic subjects. Recent insights suggest that the injured endothelial monolayer is regenerated by circulating endothelial progenitor cells (EPCs), but high glucose reduces number and functions of EPCs. Here, we tested the hypothesis that globular adiponectin can improve high glucose-suppressed EPC functions by restoration of endothelial nitric oxide synthase (eNOS) activity. Late EPCs isolated from healthy subjects appeared with cobblestone shape at 2-4 weeks. EPCs were incubated with high glucose (25 mM) and treatment with globular adiponectin for functional study. Migration and tube formation assays were used to evaluate the vasculogenetic capacity of EPCs. The activities of eNOS, Akt and concentrations of nitric oxide (NO) were also determined. Administration of globular adiponectin at physiological concentrations promoted EPC migration and tube formation, and dose-dependently upregulated phosphorylation of eNOS, Akt and augmented NO production. Chronic incubation of EPCs in high-glucose medium significantly impaired EPC function and induced cellular senescence, but these suppression effects were reversed by treatment with globular adiponectin. Globular adiponectin reversed high glucose-impaired EPC functions through NO- and p38 MAPK-related mechanisms. In addition, nude mice that received EPCs treated with adiponectin in high glucose medium showed a significant improvement in blood flow than those received normal saline and EPCs incubated in high glucose conditions. The administration of globular adiponectin improved high glucose-impaired EPC functions in vasculogenesis by restoration of eNOS activity. These beneficial effects may provide some novel rational to the vascular protective properties of adiponectin.

  6. Nogo-B regulates endothelial sphingolipid homeostasis to control vascular function and blood pressure

    PubMed Central

    Kothiya, Milankumar; Galvani, Sylvain; Obinata, Hideru; Bucci, Mariarosaria; Giordano, Frank J; Jiang, Xian-Cheng; Hla, Timothy; Di Lorenzo, Annarita

    2015-01-01

    Endothelial dysfunction is a critical factor in many cardiovascular diseases, including hypertension. Although lipid signaling has been implicated in endothelial dysfunction and cardiovascular disease, specific molecular mechanisms are poorly understood. Here we report that Nogo-B, a membrane protein of the endoplasmic reticulum, regulates endothelial sphingolipid biosynthesis with direct effects on vascular function and blood pressure. Nogo-B inhibits serine palmitoyltransferase, the rate-limiting enzyme of the de novo sphingolipid biosynthetic pathway, thereby controlling production of endothelial sphingosine 1-phosphate and autocrine, G protein–coupled receptor–dependent signaling by this metabolite. Mice lacking Nogo-B either systemically or specifically in endothelial cells are hypotensive, resistant to angiotensin II–induced hypertension and have preserved endothelial function and nitric oxide release. In mice that lack Nogo-B, pharmacological inhibition of serine palmitoyltransferase with myriocin reinstates endothelial dysfunction and angiotensin II–induced hypertension. Our study identifies Nogo-B as a key inhibitor of local sphingolipid synthesis and shows that autocrine sphingolipid signaling within the endothelium is critical for vascular function and blood pressure homeostasis. PMID:26301690

  7. Down-regulation of pigment epithelium-derived factor in uveitic lesion associates with focal vascular endothelial growth factor expression and breakdown of the blood-retinal barrier.

    PubMed

    Deeg, Cornelia A; Altmann, Frank; Hauck, Stefanie M; Schoeffmann, Stephanie; Amann, Barbara; Stangassinger, Manfred; Ueffing, Marius

    2007-05-01

    Spontaneous equine recurrent uveitis (ERU) is an incurable autoimmune disease affecting the eye. Identifying biological markers or pathways associated with this disease may allow the understanding of its pathogenesis at a molecular level. The vitreous is the body fluid closest to the disease-affected tissue and possibly also an effector of pathological processes relevant for ERU. Surgical removal of vitreous leads to cessation of relapses in spontaneous uveitis of both man and horse, therefore vitreous composites are likely to contribute to disease progression. Uveitic vitreous is likely to contain potential biomarkers in relatively undiluted quantities. With the goal to identify these markers, we systematically compared vitreous from healthy and disease-affected eyes by proteomic profiling. Nine differentially expressed proteins were identified, that are functionally related to immune response, inflammation, and maintenance of the blood-retinal barrier. One of these, pigment epithelium-derived factor, a protein involved in maintaining a proper blood-retina barrier as well as protecting from neoangiogenesis was additionally found to be down-regulated within uveitic retinal lesions whereas, conversely, vascular endothelial growth factor was found to be up-regulated at these sites. Together, these changes point to as of yet undiscovered biological pathways involved in the pathogenesis of this autoimmune disease.

  8. Lung endothelial barrier protection by resveratrol involves inhibition of HMGB1 release and HMGB1-induced mitochondrial oxidative damage via an Nrf2-dependent mechanism.

    PubMed

    Dong, Wen-Wen; Liu, Yu-Jian; Lv, Zhou; Mao, Yan-Fei; Wang, Ying-Wei; Zhu, Xiao-Yan; Jiang, Lai

    2015-11-01

    High-mobility group box 1 (HMGB1) contributes to lung vascular hyperpermeability during ventilator-induced lung injury. We aimed to determine whether the natural antioxidant resveratrol protected against HMGB1-induced endothelial hyperpermeability both in vitro and in vivo. We found that HMGB1 decreased vascular endothelial (VE)-cadherin expression and increased endothelial permeability, leading to mitochondrial oxidative damage in primary cultured mouse lung vascular endothelial cells (MLVECs). Both the mitochondrial superoxide dismutase 2 mimetic MnTBAP and resveratrol blocked HMGB1-induced mitochondrial oxidative damage, VE-cadherin downregulation, and endothelial hyperpermeability. In in vivo studies, anesthetized male ICR mice were ventilated for 4h using low tidal volume (6 ml/kg) or high tidal volume (HVT; 30 ml/kg) ventilation. The mice were injected intraperitoneally with resveratrol immediately before the onset of ventilation. We found that resveratrol attenuated HVT-associated lung vascular hyperpermeability and HMGB1 production. HVT caused a significant increase in nuclear factor-erythroid 2-related factor 2 (Nrf2) nuclear translocation and Nrf2 target gene expression in lung tissues, which was further enhanced by resveratrol treatment. HMGB1 had no effect on Nrf2 activation, whereas resveratrol treatment activated the Nrf2 signaling pathway in HMGB1-treated MLVECs. Moreover, Nrf2 knockdown reversed the inhibitory effects of resveratrol on HMGB1-induced mitochondrial oxidative damage and endothelial hyperpermeability. The inhibitory effect of resveratrol on cyclic stretch-induced HMGB1 mRNA expression in primary cultured MLVECs was also abolished by Nrf2 knockdown. In summary, this study demonstrates that resveratrol protects against lung endothelial barrier dysfunction initiated by HVT. Lung endothelial barrier protection by resveratrol involves inhibition of mechanical stretch-induced HMGB1 release and HMGB1-induced mitochondrial oxidative damage

  9. Isolation, characterization, and functional analysis of ferret lymphatic endothelial cells.

    PubMed

    Berendam, Stella J; Fallert Junecko, Beth A; Murphey-Corb, Michael A; Fuller, Deborah H; Reinhart, Todd A

    2015-02-15

    The lymphatic endothelium (LE) serves as a conduit for transport of immune cells and soluble antigens from peripheral tissues to draining lymph nodes (LNs), contributing to development of host immune responses and possibly dissemination of microbes. Lymphatic endothelial cells (LECs) are major constituents of the lymphatic endothelium. These specialized cells could play important roles in initiation of host innate immune responses through sensing of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs), including toll-like receptors (TLRs). LECs secrete pro-inflammatory cytokines and chemokines to create local inflammatory conditions for recruitment of naïve antigen presenting cells (APCs) such as dendritic cells (DCs) to sites of infection and/or vaccine administration. In this study, we examined the innate immune potential of primary LEC populations derived from multiple tissues of an animal model for human infectious diseases - the ferret. We generated a total of six primary LEC populations from lung, tracheal, and mesenteric LN tissues from three different ferrets. Standard RT-PCR characterization of these primary LECs showed that they varied in their expression of LEC markers. The ferret LECs were examined for their ability to respond to poly I:C (TLR3 and RIG-I ligand) and other known TLR ligands as measured by production of proinflammatory cytokine (IFNα, IL6, IL10, Mx1, and TNFα) and chemokine (CCL5, CCL20, and CXCL10) mRNAs using real time RT-PCR. Poly I:C exposure induced robust proinflammatory responses by all of the primary ferret LECs. Chemotaxis was performed to determine the functional activity of CCL20 produced by the primary lung LECs and showed that the LEC-derived CCL20 was abundant and functional. Taken together, our results continue to reveal the innate immune potential of primary LECs during pathogen-host interactions and expand our understanding of the roles LECs might play in health and disease in animal

  10. Coronary heart disease risk equivalence in diabetes and arterial diseases characterized by endothelial function and endothelial progenitor cell.

    PubMed

    Liao, Yun-fei; Feng, Yong; Chen, Lu-Lu; Zeng, Tian-shu; Yu, Fan; Hu, Li-jun

    2014-01-01

    Peripheral Arterial Disease (PAD), Carotid Artery Disease (CAD), and Type 2 Diabetes Mellitus (DM) were considered as "Coronary Heart Disease (CHD) risk equivalents". Vascular endothelial dysfunction was recognized as an early event in the development of atherosclerosis. Involved in neovasculogenesis and maintenance of vascular homeostasis, endothelial progenitor cell (EPC) has been considered as a biological marker of cardiovascular disease. The purpose of this study was to assess the CHD risk equivalents concept by investigating the endothelial function and circulating EPC number in patients with CHD, PAD, CAD and T2DM. There were four groups in the study: CHD (n = 19), AD [PAD and CAD (n = 17)], DM (n = 21) and healthy controls (HC, n = 20). PAD and CAD were assessed by ultrasonography. Coronal artery angiography was used to identify CHD. The diagnosis of T2DM was based on oral glucose tolerance test and medical history. Vascular endothelial function was assessed by flow-mediated brachial artery dilatation (FMD). Circulating EPC was quantified by flow cytometry. The circulating EPC numbers in four groups were CHD, 973 ± 96; AD, 1048 ± 97; T2DM, 1210 ± 125; HC, 1649 ± 112 cells/ml. There were no significant differences in circulating EPC numbers between CHD and AD groups (P > 0.05). Compared with CHD or AD group, T2DM group was associated with a slight increase in circulating EPC numbers (P < 0.05). The results of FMD were almost similar to the circulating EPC numbers(CHD, 4.06 ± 0.54; AD, 3.90 ± 0.48; DM, 3.85 ± 0.57; HC, 5.52 ± 0.67%)except that there was no significant difference among the CHD, AD and T2DM groups (P > 0.05). Age, glycosylated hemoglobin, low density lipoprotein cholesterol, systolic blood pressure, body mass index (BMI) and medical history were the independent risk factors of circulating EPC number in all the patients (P < 0.05). Age, total cholesterol, BMI and medical history were the independent risk factors of FMD in all of the

  11. Fo Shou San, an ancient Chinese herbal decoction, protects endothelial function through increasing endothelial nitric oxide synthase activity.

    PubMed

    Bi, Cathy W C; Xu, Li; Tian, Xiao Yu; Liu, Jian; Zheng, Ken Y Z; Lau, Chi Wai; Lau, David T W; Choi, Roy C Y; Dong, Tina T X; Huang, Yu; Tsim, Karl W K

    2012-01-01

    Fo Shou San (FSS) is an ancient herbal decoction comprised of Chuanxiong Rhizoma (CR; Chuanxiong) and Angelicae Sinensis Radix (ASR; Danggui) in a ratio of 2:3. Previous studies indicate that FSS promotes blood circulation and dissipates blood stasis, thus which is being used widely to treat vascular diseases. Here, we aim to determine the cellular mechanism for the vascular benefit of FSS. The treatment of FSS reversed homocysteine-induced impairment of acetylcholine (ACh)-evoked endothelium-dependent relaxation in aortic rings, isolated from rats. Like radical oxygen species (ROS) scavenger tempol, FSS attenuated homocysteine-stimulated ROS generation in cultured human umbilical vein endothelial cells (HUVECs), and it also stimulated the production of nitric oxide (NO) as measured by fluorescence dye and biochemical assay. In addition, the phosphorylation levels of both Akt kinase and endothelial NO synthases (eNOS) were markedly increased by FSS treatment, which was abolished by an Akt inhibitor triciribine. Likewise, triciribine reversed FSS-induced NO production in HUVECs. Finally, FSS elevated intracellular Ca(2+) levels in HUVECs, and the Ca(2+) chelator BAPTA-AM inhibited the FSS-stimulated eNOS phosphorylation. The present results show that this ancient herbal decoction benefits endothelial function through increased activity of Akt kinase and eNOS; this effect is causally via a rise of intracellular Ca(2+) and a reduction of ROS.

  12. The Small GTPase Rap1 Is a Novel Regulator of RPE Cell Barrier Function

    PubMed Central

    Wittchen, Erika S.

    2011-01-01

    Purpose. To determine whether the small GTPase Rap1 regulates the formation and maintenance of the retinal pigment epithelial (RPE) cell junctional barrier. Methods. An in vitro model was used to study RPE barrier properties. To dissect the role of Rap1, two techniques were used to inhibit Rap1 function: overexpression of RapGAP, which acts as a negative regulator of endogenous Rap1 activity, and treatment with engineered, adenovirally-transduced microRNAs to knockdown Rap1 protein expression. Transepithelial electrical resistance (TER) and real-time cellular analysis (RTCA) of impedance were used as readouts for barrier properties. Immunofluorescence microscopy was used to visualize localization of cadherins under steady state conditions and also during junctional reassembly after calcium switch. Finally, choroidal endothelial cell (CEC) migration across RPE monolayers was quantified under conditions of Rap1 inhibition in RPE. Results. Knockdown of Rap1 or inhibition of its activity in RPE reduces TER and electrical impedance of the RPE monolayers. The loss of barrier function is also reflected by the mislocalization of cadherins and formation of gaps within the monolayer. TER measurement and immunofluorescent staining of cadherins after a calcium switch indicate that junctional reassembly kinetics are also impaired. Furthermore, CEC transmigration is significantly higher in Rap1-knockdown RPE monolayers compared with control. Conclusions. Rap1 GTPase is an important regulator of RPE cell junctions, and is required for maintenance of barrier function. This observation that RPE monolayers lacking Rap1 allow greater transmigration of CECs suggests a possible role for potentiating choroidal neovascularization during the pathology of neovascular age-related macular degeneration. PMID:21873678

  13. BBB on chip: microfluidic platform to mechanically and biochemically modulate blood-brain barrier function.

    PubMed

    Griep, L M; Wolbers, F; de Wagenaar, B; ter Braak, P M; Weksler, B B; Romero, I A; Couraud, P O; Vermes, I; van der Meer, A D; van den Berg, A

    2013-02-01

    The blood-brain barrier (BBB) is a unique feature of the human body, preserving brain homeostasis and preventing toxic substances to enter the brain. However, in various neurodegenerative diseases, the function of the BBB is disturbed. Mechanisms of the breakdown of the BBB are incompletely understood and therefore a realistic model of the BBB is essential. We present here the smallest model of the BBB yet, using a microfluidic chip, and the immortalized human brain endothelial cell line hCMEC/D3. Barrier function is modulated both mechanically, by exposure to fluid shear stress, and biochemically, by stimulation with tumor necrosis factor alpha (TNF-α), in one single device. The device has integrated electrodes to analyze barrier tightness by measuring the transendothelial electrical resistance (TEER). We demonstrate that hCMEC/D3 cells could be cultured in the microfluidic device up to 7 days, and that these cultures showed comparable TEER values with the well-established Transwell assay, with an average (± SEM) of 36.9 Ω.cm(2) (± 0.9 Ω.cm(2)) and 28.2 Ω.cm(2) (± 1.3 Ω.cm(2)) respectively. Moreover, hCMEC/D3 cells on chip expressed the tight junction protein Zonula Occludens-1 (ZO-1) at day 4. Furthermore, shear stress positively influenced barrier tightness and increased TEER values with a factor 3, up to 120 Ω.cm(2). Subsequent addition of TNF-α decreased the TEER with a factor of 10, down to 12 Ω.cm(2). This realistic microfluidic platform of the BBB is very well suited to study barrier function in detail and evaluate drug passage to finally gain more insight into the treatment of neurodegenerative diseases.

  14. Effects of Olmesartan on Endothelial Progenitor Cell Mobilization and Function in Carotid Atherosclerosis

    PubMed Central

    Gong, Xin; Shao, Li; Fu, Yi-Min; Zou, Yong

    2015-01-01

    Background Olmesartan is a type of angiotensin II receptor inhibitor that can reduce the incidence of cardiovascular events. However, its role in the function of endothelial progenitor cells in atherosclerosis patients is still unclear. Our study aimed to explore the effects and mechanism of olmesartan on endothelial progenitor cell mobilization and function in carotid atherosclerosis. Material/Methods Forty carotid atherosclerosis patients were enrolled. Patients were administrated olmesartan 20 mg/day for 3 months. Flow cytometry was used for counting circulating endothelial progenitor cells; colorimetric method was used to measure the serum levels of endothelial nitric oxide synthase and nitric oxide. Cell migration, adhesion, and proliferation capacity, and related signaling pathway were also analyzed. Spearman rank correlation analysis was used to investigate the influence of olmesartan on endothelial progenitor cells and clinical characteristics (e.g., sex, age, blood pressure). Results Compared with the control group, the number of circulating endothelial progenitor cells was significantly decreased. Olmesartan can increase circulating endothelial progenitor cells number and the serum levels of eNOS and NO. Furthermore, it can improve cell migration, adhesion, and proliferation capacities. Spearman rank correlation analysis showed there is no relationship between olmesartan promotion effects on endothelial progenitor cell mobilization and the clinical characteristics (P>0.05). P-eNOS and P-Akt expression can be unregulated by RNH-6270 treatment and blocked by LY294002. Conclusions Olmesartan can effectively promote the endothelial progenitor cells mobilization and improve their function in patients with carotid atherosclerosis, independent of basic characteristics. This process relies on the PI3K/Akt/eNOS signaling pathway. PMID:25913171

  15. Effects of olmesartan on endothelial progenitor cell mobilization and function in carotid atherosclerosis.

    PubMed

    Gong, Xin; Shao, Li; Fu, Yi-Min; Zou, Yong

    2015-04-26

    Olmesartan is a type of angiotensin II receptor inhibitor that can reduce the incidence of cardiovascular events. However, its role in the function of endothelial progenitor cells in atherosclerosis patients is still unclear. Our study aimed to explore the effects and mechanism of olmesartan on endothelial progenitor cell mobilization and function in carotid atherosclerosis. Forty carotid atherosclerosis patients were enrolled. Patients were administrated olmesartan 20 mg/day for 3 months. Flow cytometry was used for counting circulating endothelial progenitor cells; colorimetric method was used to measure the serum levels of endothelial nitric oxide synthase and nitric oxide. Cell migration, adhesion, and proliferation capacity, and related signaling pathway were also analyzed. Spearman rank correlation analysis was used to investigate the influence of olmesartan on endothelial progenitor cells and clinical characteristics (e.g., sex, age, blood pressure). Compared with the control group, the number of circulating endothelial progenitor cells was significantly decreased. Olmesartan can increase circulating endothelial progenitor cells number and the serum levels of eNOS and NO. Furthermore, it can improve cell migration, adhesion, and proliferation capacities. Spearman rank correlation analysis showed there is no relationship between olmesartan promotion effects on endothelial progenitor cell mobilization and the clinical characteristics (P>0.05). P-eNOS and P-Akt expression can be unregulated by RNH-6270 treatment and blocked by LY294002. Olmesartan can effectively promote the endothelial progenitor cells mobilization and improve their function in patients with carotid atherosclerosis, independent of basic characteristics. This process relies on the PI3K/Akt/eNOS signaling pathway.

  16. Phenotypic, genotypic, and functional characterization of normal and acute myeloid leukemia-derived marrow endothelial cells.

    PubMed

    Pizzo, Russell J; Azadniv, Mitra; Guo, Naxin; Acklin, Joshua; Lacagnina, Kimberly; Coppage, Myra; Liesveld, Jane L

    2016-05-01

    In addition to participation in homing, egress, and transmigration of hematopoietic cells, marrow endothelium also contributes to cell proliferation and survival. Endothelial cells from multiple vascular beds are able to prevent spontaneous or therapy-induced apoptosis in acute myelogenous leukemia (AML) blasts. Marrow-derived endothelial cells from leukemia patients have not been well-characterized, and in this work, endothelial cells were purified from marrow aspirates from normal subjects or from newly diagnosed AML patients to compare these cells phenotypically and functionally. By reverse transcription polymerase chain reaction, these cells express CD31, Tie-2, vascular endothelial growth factor (VEGF), and endothelial nitric oxide synthase (eNOS), supporting endothelial origin. They take up acetyl low-density lipoprotein and are able to form tubular structures. Culture of AML cells with endothelial cells from both normal and AML subjects supported adhesion, transmigration, and leukemia colony-forming unit outgrowth. RNA-sequencing analysis revealed 130 genes significantly up- or downregulated in AML-derived endothelial cells as compared with those derived from normal marrow. The genes differentially expressed (p < 0.001) were included in biological function categories involving cancer, cell development, cell growth and proliferation, cell signaling, inflammatory response, and cell death and survival. Further pathway analysis revealed upregulation of c-Fos and genes involved in chemotaxis such as CXCL16. AML-derived endothelial cells are similar in phenotype and function to their normal marrow-derived counterparts, but genomic analysis suggests a differential signature with altered expression of genes, which could play a role in leukemogenesis or leukemia cell maintenance in the marrow microenvironment. Copyright © 2016 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.

  17. Salmon-derived thrombin inhibits development of chronic pain through an endothelial barrier protective mechanism dependent on APC

    PubMed Central

    Smith, Jenell R; Galie, Peter A; Slochower, David R; Weisshaar, Christine L.; Janmey, Paul A; Winkelstein, Beth A

    2015-01-01

    Many neurological disorders are initiated by blood-brain barrier breakdown, which potentiates spinal neuroinflammation and neurodegeneration. Peripheral neuropathic injuries are known to disrupt the blood-spinal cord barrier (BSCB) and to potentiate inflammation. But, it is not known whether BSCB breakdown facilitates pain development. In this study, a neural compression model in the rat was used to evaluate relationships among BSCB permeability, inflammation and pain-related behaviors. BSCB permeability increases transiently only after injury that induces mechanical hyperalgesia, which correlates with serum concentrations of pro-inflammatory cytokines, IL-7, IL-12, IL-1α and TNF-α. Mammalian thrombin dually regulates vascular permeability through PAR1 and activated protein C (APC). Since thrombin protects vascular integrity through APC, directing its affinity towards protein C, while still promoting coagulation, might be an ideal treatment for BSCB-disrupting disorders. Salmon thrombin, which prevents the development of mechanical allodynia, also prevents BSCB breakdown after neural injury and actively inhibits TNF-α-induced endothelial permeability in vitro, which is not evident the case for human thrombin. Salmon thrombin’s production of APC faster than human thrombin is confirmed using a fluorogenic assay and APC is shown to inhibit BSCB breakdown and pain-related behaviors similar to salmon thrombin. Together, these studies highlight the impact of BSCB on pain and establish salmon thrombin as an effective blocker of BSCB, and resulting nociception, through its preferential affinity for protein C. PMID:26708087

  18. Human brain endothelial cell-derived COX-2 facilitates extravasation of breast cancer cells across the blood-brain barrier.

    PubMed

    Lee, Kyue Yim; Kim, Youn-Jae; Yoo, Heon; Lee, Seung Hoon; Park, Jong Bae; Kim, Ho Jin

    2011-12-01

    With improvements in systemic control, metastasis to the brain has been more frequently found in patients with breast cancer. In order to gain access to the brain, breast cancer cells must overcome the blood-brain barrier (BBB), a highly selective filter against cellular and soluble substances. Human brain endothelial cells (HBECs) comprise a major element of the BBB, and breast cancer cells first encounter and pass through them for extravasation. To date, however, the precise role of HBECs in metastasis to the brain is unknown. In this study, we examined how HBECs take part in the extravasation process. In an established in vitro model of the BBB, unexpectedly, the transmigration of breast cancer cells was markedly enhanced in the presence of HBECs than in their absence, suggesting that HBECs facilitate the transmigration of breast cancer cells rather than acting as a barrier against them. We then showed that cyclooxygenase (COX-2) induced from HBECs rather than that from breast cancer cells plays a key role in the transmigration. Moreover, expression of matrix metalloproteinase (MMP-2) mediating the transmigration was induced in HBECs by COX-2 after co-culture with breast cancer cells. Taken together, our results suggest that COX-2 and MMP-2 produced from HBECs facilitate the extravasation of breast cancer cells across the BBB.

  19. Anti-IL-6 neutralizing antibody modulates blood-brain barrier function in the ovine fetus.

    PubMed

    Zhang, Jiyong; Sadowska, Grazyna B; Chen, Xiaodi; Park, Seon Yeong; Kim, Jeong-Eun; Bodge, Courtney A; Cummings, Erin; Lim, Yow-Pin; Makeyev, Oleksandr; Besio, Walter G; Gaitanis, John; Banks, William A; Stonestreet, Barbara S

    2015-05-01

    Impaired blood-brain barrier function represents an important component of hypoxic-ischemic brain injury in the perinatal period. Proinflammatory cytokines could contribute to ischemia-related blood-brain barrier dysfunction. IL-6 increases vascular endothelial cell monolayer permeability in vitro. However, contributions of IL-6 to blood-brain barrier abnormalities have not been examined in the immature brain in vivo. We generated pharmacologic quantities of ovine-specific neutralizing anti-IL-6 mAbs and systemically infused mAbs into fetal sheep at 126 days of gestation after exposure to brain ischemia. Anti-IL-6 mAbs were measured by ELISA in fetal plasma, cerebral cortex, and cerebrospinal fluid, blood-brain barrier permeability was quantified using the blood-to-brain transfer constant in brain regions, and IL-6, tight junction proteins, and plasmalemma vesicle protein (PLVAP) were detected by Western immunoblot. Anti-IL-6 mAb infusions resulted in increases in mAb (P < 0.05) in plasma, brain parenchyma, and cerebrospinal fluid and decreases in brain IL-6 protein. Twenty-four hours after ischemia, anti-IL-6 mAb infusions attenuated ischemia-related increases in blood-brain barrier permeability and modulated tight junction and PLVAP protein expression in fetal brain. We conclude that inhibiting the effects of IL-6 protein with systemic infusions of neutralizing antibodies attenuates ischemia-related increases in blood-brain barrier permeability by inhibiting IL-6 and modulates tight junction proteins after ischemia.

  20. Systemic endothelial function is preserved in men with both active and inactive variant angina pectoris.

    PubMed

    Ito, K; Akita, H; Kanazawa, K; Yamada, S; Shiga, N; Terashima, M; Matsuda, Y; Takai, E; Iwai, C; Takaoka, H; Yokoyama, M

    1999-12-01

    To test the hypothesis that coronary spasm could be a coronary manifestation of systemic endothelial dysfunction and that the activity of coronary spasm could influence systemic endothelial function, we examined brachial flow-mediated, endothelium-dependent vasodilation and nitroglycerin-induced endothelium-independent vasodilation with high-resolution ultrasound in 11 men with variant angina pectoris (6 active and 5 inactive) without established coronary atherosclerosis. Endothelium-dependent vasodilation in peripheral circulation was preserved in men with active and inactive variant angina pectoris, suggesting that systemic endothelial dysfunction is not involved in either the pathogenesis or the activity of coronary spasm.

  1. Surfactants have multi-fold effects on skin barrier function.

    PubMed

    Lemery, Emmanuelle; Briançon, Stéphanie; Chevalier, Yves; Oddos, Thierry; Gohier, Annie; Boyron, Olivier; Bolzinger, Marie-Alexandrine

    2015-01-01

    The stratum corneum (SC) is responsible for the barrier properties of the skin and the role of intercorneocyte skin lipids, particularly their structural organization, in controlling SC permeability is acknowledged. Upon contacting the skin, surfactants interact with the SC components leading to barrier damage. To improve knowledge of the effect of several classes of surfactant on skin barrier function at three different levels. The influence of treatments of human skin explants with six non-ionic and four ionic surfactant solutions on the physicochemical properties of skin was investigated. Skin surface wettability and polarity were assessed through contact angle measurements. Infrared spectroscopy allowed monitoring the SC lipid organization. The lipid extraction potency of surfactants was evaluated thanks to HPLC-ELSD assays. One anionic and one cationic surfactant increased the skin polarity by removing the sebaceous and epidermal lipids and by disturbing the organization of the lipid matrix. Another cationic surfactant displayed a detergency effect without disturbing the skin barrier. Several non-ionic surfactants disturbed the lipid matrix organization and modified the skin wettability without any extraction of the skin lipids. Finally two non-ionic surfactants did not show any effect on the investigated parameters or on the skin barrier. The polarity, the organization of the lipid matrix and the lipid composition of the skin allowed describing finely how surfactants can interact with the skin and disturb the skin barrier function.

  2. Karyopherins regulate nuclear pore complex barrier and transport function.

    PubMed

    Kapinos, Larisa E; Huang, Binlu; Rencurel, Chantal; Lim, Roderick Y H

    2017-09-01

    Nucleocytoplasmic transport is sustained by karyopherins (Kaps) and a Ran guanosine triphosphate (RanGTP) gradient that imports nuclear localization signal (NLS)-specific cargoes (NLS-cargoes) into the nucleus. However, how nuclear pore complex (NPC) barrier selectivity, Kap traffic, and NLS-cargo release are systematically linked and simultaneously regulated remains incoherent. In this study, we show that Kapα facilitates Kapβ1 turnover and occupancy at the NPC in a RanGTP-dependent manner that is directly coupled to NLS-cargo release and NPC barrier function. This is underpinned by the binding affinity of Kapβ1 to phenylalanine-glycine nucleoporins (FG Nups), which is comparable with RanGTP·Kapβ1, but stronger for Kapα·Kapβ1. On this basis, RanGTP is ineffective at releasing standalone Kapβ1 from NPCs. Depleting Kapα·Kapβ1 by RanGTP further abrogates NPC barrier function, whereas adding back Kapβ1 rescues it while Kapβ1 turnover softens it. Therefore, the FG Nups are necessary but insufficient for NPC barrier function. We conclude that Kaps constitute integral constituents of the NPC whose barrier, transport, and cargo release functionalities establish a continuum under a mechanism of Kap-centric control. © 2017 Kapinos et al.

  3. Effects of different degrees of insulin sensitivity on endothelial function in obese patients.

    PubMed

    Galvão, Roberto; Plavnik, Frida Liane; Ribeiro, Fernando Flexa; Ajzen, Sérgio Aron; Christofalo, Dejaldo M de J; Kohlmann, Osvaldo

    2012-01-01

    Obesity derived from intra-abdominal fat deposition tends to increase hormonal and cytokine production, thus worsening insulin sensitivity and leading to endothelial dysfunction. Hyperinsulinemia is considered an independent risk factor for ischemic heart disease and cause of endothelial dysfunction in healthy individuals. To assess the impact of different degrees of insulin resistance, measured by HOMA-IR (Homeostasis Model Assessment of Insulin Resistance), on endothelial function in obese, non-diabetic patients without prior history of cardiovascular events and different metabolic syndrome components. Forty obese individuals were submitted to anthropometric measurements, BP measurements at office and ABPM and laboratory tests, in addition to non-invasive ultrasound assessment of endothelial function. Patients were divided into 3 groups according to the level of insulin resistance: patients with HOMA-IR values from 0.590 to 1.082 were assigned to Group 1 (n=13), from 1.083 to 1.410 to Group 2 (n=14) and from 1.610 to 2.510 to Group 3 (n=13). We found a significant difference in flow-mediated dilation in group 3 compared to group 1 (9.2 ± 7.0 vs 18.0 ± 7.5 %, p=0.006). There was a negative correlation between endothelial function and insulin, HOMA-IR and triglycerides. Our data suggest that mild changes in insulin resistance levels assessed by HOMA-IR may have an impact on vasodilatatory endothelial function in uncomplicated obese individuals with different cardiovascular risk factors.

  4. How hormones influence composition and physiological function of the brain-blood barrier.

    PubMed

    Hampl, R; Bičíková, M; Sosvorová, L

    2015-01-01

    Hormones exert many actions in the brain. Their access and effects in the brain are regulated by the blood-brain barrier (BBB). Hormones as other substances may enter the brain and vice versa either by paracellular way requiring breaching tight junctions stitching the endothelial cells composing the BBB, or by passage through the cells (transcellular way). Hormones influence both ways through their receptors, both membrane and intracellular, present on/in the BBB. In the review the main examples are outlined how hormones influence the expression and function of proteins forming the tight junctions, as well as how they regulate expression and function of major protein transporters mediating transport of various substances including hormone themselves.

  5. You're Only as Old as Your Arteries: Translational Strategies for Preserving Vascular Endothelial Function with Aging

    PubMed Central

    Kaplon, Rachelle E.; Gioscia-Ryan, Rachel A.; LaRocca, Thomas J.

    2014-01-01

    Endothelial dysfunction develops with age and increases the risk of age-associated vascular disorders. Nitric oxide insufficiency, oxidative stress, and chronic low-grade inflammation, induced by upregulation of adverse cellular signaling processes and imbalances in stress resistance pathways, mediate endothelial dysfunction with aging. Healthy lifestyle behaviors preserve endothelial function with aging by inhibiting these mechanisms, and novel nutraceutical compounds that favorably modulate these pathways hold promise as a complementary approach for preserving endothelial health. PMID:24985329

  6. Effects of propranolol and clonidine on brain edema, blood-brain barrier permeability and endothelial glycocalyx disruption following fluid-percussion brain injury in the rat.

    PubMed

    Genét, Gustav Folmer; Bentzer, Peter; Hansen, Morten Bagge; Ostrowski, Sisse Rye; Johansson, Pär Ingemar

    2017-09-20

    Traumatic brain injury causes a disruption of the vascular endothelial glycocalyx layer that is associated with an overactivation of the sympathoadrenal system. We hypothesized that early and unselective beta-blockade with propranolol alone or in combination with the alfa2-agonist clonidine would decrease brain edema, blood-brain-barrier permeability and glycocalyx disruption at 24 hours after trauma. We subjected fifty-three adult male Sprague-Dawley rats to lateral fluid-percussion brain injury and randomized infusion with propranolol (n=16), propranolol+clonidine (n=16), vehicle (n=16) or sham (n=5) for 24 hours. Primary outcome was brain water content at 24 hours. Secondary outcomes were blood-brain barrier permeability and plasma levels of syndecan-1 (glycocalyx disruption), cell damage (histone-complexed DNA fragments), epinephrine, norepinephrine, and animal motor function. We found no difference in brain water content (mean±SD) between propranolol (80.8±0.3%; 95% CI: 80.7-81.0) and vehicle (81.1±0.6%; 95% CI: 80.8-81.4) (p=0.668) or between propranolol/clonidine (80.8±0.3%; 95% CI: 80.7-81.0) and vehicle (p=0.555). We found no effect of propranolol and propranolol/clonidine on blood-brain barrier permeability and animal motor scores. Unexpectedly, propranolol and propranolol/clonidine caused an increase in epinephrine and syndecan-1 levels. This study does not provide any support for unselective beta-blockade with propranolol or the combination of propranolol and the alfa2-agonist clonidine on brain water content. The novel finding of an increase in plasma concentrations of epinephrine and syndecan-1 after propranolol treatment in traumatic brain injury is of unclear significance and should be investigated further.

  7. A study on the quantitative evaluation of skin barrier function

    NASA Astrophysics Data System (ADS)

    Maruyama, Tomomi; Kabetani, Yasuhiro; Kido, Michiko; Yamada, Kenji; Oikaze, Hirotoshi; Takechi, Yohei; Furuta, Tomotaka; Ishii, Shoichi; Katayama, Haruna; Jeong, Hieyong; Ohno, Yuko

    2015-03-01

    We propose a quantitative evaluation method of skin barrier function using Optical Coherence Microscopy system (OCM system) with coherency of near-infrared light. There are a lot of skin problems such as itching, irritation and so on. It has been recognized skin problems are caused by impairment of skin barrier function, which prevents damage from various external stimuli and loss of water. To evaluate skin barrier function, it is a common strategy that they observe skin surface and ask patients about their skin condition. The methods are subjective judgements and they are influenced by difference of experience of persons. Furthermore, microscopy has been used to observe inner structure of the skin in detail, and in vitro measurements like microscopy requires tissue sampling. On the other hand, it is necessary to assess objectively skin barrier function by quantitative evaluation method. In addition, non-invasive and nondestructive measuring method and examination changes over time are needed. Therefore, in vivo measurements are crucial for evaluating skin barrier function. In this study, we evaluate changes of stratum corneum structure which is important for evaluating skin barrier function by comparing water-penetrated skin with normal skin using a system with coherency of near-infrared light. Proposed method can obtain in vivo 3D images of inner structure of body tissue, which is non-invasive and non-destructive measuring method. We formulate changes of skin ultrastructure after water penetration. Finally, we evaluate the limit of performance of the OCM system in this work in order to discuss how to improve the OCM system.

  8. Insulin Downregulates the Transcriptional Coregulator CITED2, an Inhibitor of Proangiogenic Function in Endothelial Cells.

    PubMed

    Wang, Xuanchun; Lockhart, Samuel M; Rathjen, Thomas; Albadawi, Hassan; Sørensen, Ditte; O'Neill, Brian T; Dwivedi, Nishant; Preil, Simone R; Beck, Hans Christian; Dunwoodie, Sally L; Watkins, Michael T; Rasmussen, Lars Melholt; Rask-Madsen, Christian

    2016-12-01

    In patients with atherosclerotic complications of diabetes, impaired neovascularization of ischemic tissue in the myocardium and lower limb limits the ability of these tissues to compensate for poor perfusion. We identified 10 novel insulin-regulated genes, among them Adm, Cited2, and Ctgf, which were downregulated in endothelial cells by insulin through FoxO1. CBP/p300-interacting transactivator with ED-rich tail 2 (CITED2), which was downregulated by insulin by up to 54%, is an important negative regulator of hypoxia-inducible factor (HIF) and impaired HIF signaling is a key mechanism underlying the impairment of angiogenesis in diabetes. Consistent with impairment of vascular insulin action, CITED2 was increased in cardiac endothelial cells from mice with diet-induced obesity and from db/db mice and was 3.8-fold higher in arterial tissue from patients with type 2 diabetes than control subjects without diabetes. CITED2 knockdown promoted endothelial tube formation and endothelial cell proliferation, whereas CITED2 overexpression impaired HIF activity in vitro. After femoral artery ligation, induction of an endothelial-specific HIF target gene in hind limb muscle was markedly upregulated in mice with endothelial cell deletion of CITED2, suggesting that CITED2 can limit HIF activity in vivo. We conclude that vascular insulin resistance in type 2 diabetes contributes to the upregulation of CITED2, which impairs HIF signaling and endothelial proangiogenic function.

  9. Ecscr regulates insulin sensitivity and predisposition to obesity by modulating endothelial cell functions.

    PubMed

    Akakabe, Yoshiki; Koide, Masahiro; Kitamura, Youhei; Matsuo, Kiyonari; Ueyama, Tomomi; Matoba, Satoaki; Yamada, Hiroyuki; Miyata, Keishi; Oike, Yuichi; Ikeda, Koji

    2013-01-01

    Insulin resistance is closely associated with obesity and is one of the earliest symptoms of type-2 diabetes. Endothelial cells are involved in the pathogenesis of insulin resistance through their role in insulin delivery and adipose tissue angiogenesis. Here we show that Ecscr (endothelial cell surface expressed chemotaxis and apoptosis regulator; also known as ARIA), the transmembrane protein that regulates endothelial cell signalling, is highly expressed in white and brown adipose tissues, and regulates energy metabolism and glucose homeostasis by modulating endothelial cell functions. Ecscr-deficient mice fed a normal chow show improved glucose tolerance and enhanced insulin sensitivity. We demonstrate that Ecscr deletion enhances the insulin-mediated Akt/endothelial nitric oxide synthase activation in endothelial cells, which increases insulin delivery into the skeletal muscle. Ecscr deletion also protects mice on a high-fat diet from obesity and obesity-related metabolic disorders by enhancing adipose tissue angiogenesis. Conversely, targeted activation of Ecscr in endothelial cells impairs glucose tolerance and predisposes mice to diet-induced obesity. Our results suggest that the inactivation of Ecscr enhances insulin sensitivity and may represent a new therapeutic strategy for treating metabolic syndrome.

  10. Platelet Activating Factor-Induced Ceramide Micro-Domains Drive Endothelial NOS Activation and Contribute to Barrier Dysfunction

    PubMed Central

    Predescu, Sanda; Knezevic, Ivana; Bardita, Cristina; Neamu, Radu Florin; Brovcovych, Viktor; Predescu, Dan

    2013-01-01

    The spatial and functional relationship between platelet activating factor-receptor (PAF-R) and nitric oxide synthase (eNOS) in th