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Sample records for hypertension-induced redox-mediated endothelial

  1. Selective Serotonin-norepinephrine Re-uptake Inhibition Limits Renovas-cular-hypertension Induced Cognitive Impairment, Endothelial Dysfunction, and Oxidative Stress Injury.

    PubMed

    Singh, Prabhat; Sharma, Bhupesh

    2016-01-01

    Hypertension has been reported to induce cognitive decline and dementia of vascular origin. Serotonin- norepinephrine reuptake transporters take part in the control of inflammation, cognitive functions, motivational acts and deterioration of neurons. This study was carried out to examine the effect of venlafaxine; a specific serotonin-norepinephrine reuptake inhibitor (SNRI), in two-kidney-one-clip-2K1C (renovascular hypertension) provoked vascular dementia (VaD) in albino rats. 2K1C technique was performed to provoke renovascular-hypertension in adult male albino Wistar rats. Learning and memory were assessed by using the elevated plus maze and Morris water maze. Mean arterial blood pressure- MABP, as well as endothelial function, were assessed by means of BIOPAC system. Serum nitrosative stress (nitrite/ nitrate), aortic superoxide anion, brain oxidative stress, inflammation, cholinergic dysfunction and brain damage (2,3,5-triphenylterazolium chloride staining) were also assessed. 2K1C has increased MABP, endothelial dysfunction as well as learning and memory impairments. 2K1C method has increased serum nitrosative stress (reduced nitrite/nitrate level), oxidative stress (increased brain thiobarbituric acid reactive species and aortic superoxide anion content along with decreased levels of brain superoxide dismutase, glutathione, and catalase), brain inflammation (increased myeloperoxidase), cholinergic dysfunction (increased acetylcholinesterase activity) and brain damage. Treatment with venlafaxine considerably attenuated renovascular-hypertension induced cognition impairment, endothelial dysfunction, serum nitrosative stress, brain and aortic oxidative stress, cholinergic function, inflammation as well as cerebral damage. The finding of this study indicates that specific modulation of the serotonin-norepinephrine transporter perhaps regarded as potential interventions for the management of renovascular hypertension provoked VaD. PMID:26915517

  2. A pivotal role of the vascular endothelial growth factor signaling pathway in the formation of venous hypertension-induced dural arteriovenous fistulas.

    PubMed

    Li, Qiang; Zhang, Qi; Huang, Qing-Hai; Fang, Yi-Bin; Zhang, Zhao-Long; Xu, Yi; Liu, Jian-Min

    2014-05-01

    angiogenesis in the dura mater. In conclusion, VEGF and its receptor may be important in the formation of venous hypertension-induced DAVFs. PMID:24626343

  3. Redox mediation and hydrogen-generation with bipyridinium reagents

    DOEpatents

    Wrighton, Mark S.; Bookbinder, Dana C.; Bruce, James A.; Dominey, Raymond N.; Lewis, Nathan S.

    1984-03-27

    A variety of redox mediating agents employing bipyridinium reagents and such reagents in conjunction with dispersed noble metals, such as platinium, are disclosed as coatings for substrates and electrodes. The agents may be charged by an applied voltage or by photoelectric effects or may be equilibrated with hydrogen. The agents are useful in reducing biological materials and electrolytic hydrogen production.

  4. A redox-mediated chromogenic reaction and application in immunoassay.

    PubMed

    Yu, Ru-Jia; Ma, Wei; Peng, Mao-Pan; Bai, Zhi-Shan; Long, Yi-Tao

    2016-08-31

    A novel redox-mediated chromogenic reaction was demonstrated based on the reaction between HAuCl4 and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), which generate various color responses from red to green in the resulting solutions. Various redox substance could be used to mediate the reaction and trigger a distinct color response. We established a sensitive hydrogen peroxide colorimetric sensor based on the redox-mediated chromogenic reaction and depicted the application both in detection of enzyme and in an immunoassay. Combining the traditional chromogenic reagent with gold nanoparticles, our assay has the advantage in short response time (within three minutes), high sensitivity (10(-12) g mL(-1) for HBsAg) and stability. PMID:27506364

  5. Enhanced microbial decolorization of methyl red with oxidized carbon fiber as redox mediator.

    PubMed

    Emilia Rios-Del Toro, E; Celis, Lourdes B; Cervantes, Francisco J; Rangel-Mendez, J Rene

    2013-09-15

    The anaerobic degradation of azo dyes under anaerobic conditions is possible but at a slow rate. Redox mediators (quinones, activated carbon) are used to improve the reduction rate. The aim of this work was to use activated carbon fiber (ACF) as a redox mediator for the anaerobic reduction of the azo dye methyl red. ACF was chemically modified with 8M HNO₃ to increase its redox-mediating capacity and used in chemical and anaerobic biological batch assays for the reduction of methyl red. ACF increased its redox-mediating capacity up to 3-fold in chemical assays; in biological assays ACF increased the reduction rate up to 8-fold compared to controls without ACF. However, since the ACF served as support for biomass, a biofilm formed on the fiber significantly reduced its redox-mediating capacity; substrate consumption suggested that the electron transport from ACF to methyl red was the rate-limiting step in the process. These results are the first evidence of the role of ACF as a redox mediator in the reductive decolorization of methyl red, in addition to the effect of biofilm attached to ACF on methyl red reduction. Due to the versatile characteristics of ACF and its redox-mediating capacity, carbon fibers could be used in biological wastewater treatment systems to accelerate the reductive transformation of pollutants commonly found in industrial effluents.

  6. Enhanced microbial decolorization of methyl red with oxidized carbon fiber as redox mediator.

    PubMed

    Emilia Rios-Del Toro, E; Celis, Lourdes B; Cervantes, Francisco J; Rangel-Mendez, J Rene

    2013-09-15

    The anaerobic degradation of azo dyes under anaerobic conditions is possible but at a slow rate. Redox mediators (quinones, activated carbon) are used to improve the reduction rate. The aim of this work was to use activated carbon fiber (ACF) as a redox mediator for the anaerobic reduction of the azo dye methyl red. ACF was chemically modified with 8M HNO₃ to increase its redox-mediating capacity and used in chemical and anaerobic biological batch assays for the reduction of methyl red. ACF increased its redox-mediating capacity up to 3-fold in chemical assays; in biological assays ACF increased the reduction rate up to 8-fold compared to controls without ACF. However, since the ACF served as support for biomass, a biofilm formed on the fiber significantly reduced its redox-mediating capacity; substrate consumption suggested that the electron transport from ACF to methyl red was the rate-limiting step in the process. These results are the first evidence of the role of ACF as a redox mediator in the reductive decolorization of methyl red, in addition to the effect of biofilm attached to ACF on methyl red reduction. Due to the versatile characteristics of ACF and its redox-mediating capacity, carbon fibers could be used in biological wastewater treatment systems to accelerate the reductive transformation of pollutants commonly found in industrial effluents. PMID:23892163

  7. Critical Role of Redox Mediator in Suppressing Charging Instabilities of Lithium-Oxygen Batteries.

    PubMed

    Liang, Zhuojian; Lu, Yi-Chun

    2016-06-22

    Redox mediators have been widely applied to reduce the charge overpotentials of lithium-oxygen (Li-O2) batteries. Here, we reveal the critical role of redox mediator in suppressing the charging instability of Li-O2 batteries. Using high temporal resolution online electrochemical mass spectrometry, we show that charging with redox mediators (using lithium bromide as a model system) significantly reduces parasitic gas evolution and improves oxygen recovery efficiency. Using redox mediator transforms the charge reactions from electrochemical pathways to chemical pathways, which unexpectedly bypasses the formation of highly reactive intermediates upon electro-oxidation of lithium peroxide (Li2O2). Such transformation reduces self-amplifying degradation reactions of electrode and electrolyte in Li-O2 cells. We further show that the improved stability associated with the redox mediator is much more pronounced at higher charging rates, owing to fast charge-transfer kinetics of the redox mediator. Together, we show that employing redox mediator not only reduces the charge overpotential but also suppresses side reactions of Li-O2 cells with improved charging rate. Our work demonstrates that transforming electro-oxidation of Li2O2 to chemical oxidation of Li2O2 is a promising strategy to simultaneously mitigate charging side reactions and achieve low overpotential for the Li-O2 batteries. PMID:27228413

  8. [Biocatalyst of redox mediators on the denitrification by Paracoccus versutus strain GW1].

    PubMed

    Li, Hai-Bo; Lian, Jing; Guo, Yan-Kai; Zhao, Li-Jun; Du, Hai-Feng; Yang, Jing-Liang; Guo, Jian-Bo

    2012-07-01

    The quinone respiration process of Paracoccus versutus strain GW1 was characterized and the effects of the four redox mediators on the denitrification process were studied. The experiment results suggested that quinones were utilized by Paracoccus versutus strain GW1 as electron acceptors in the respiratory chain and reduced to hydroquinone. Batch experiments were carried out to investigate the biocatalyst effect of redox mediators as catalyst on the denitrification process at 35 degrees C. All four redox mediators tested were able to enhance the nitrate removal efficiency and the denitrification efficiency by 1.14-1.63 fold and 1.12-2.02 fold, respectively. The accelerating effect from high to low was AQDS > 1,5-AQDS > AQS > alpha-AQS. In the presence of redox mediators, the stabilized ORP values in the nitrate decomposition process were reduced by 33-75 mV. The pH variations in denitrification with redox mediators showed similar tendency to that of the conventional nitrate removal process. In the concentration range of 0-0.32 mmol x L(-1), AQDS had the best accelerating effect and a linear correlation was found for the denitrification rate K and the AQDS concentration cAQDS. This study indicated that the application of redox mediators significantly improved the denitrification process by enhancing the decomposition rate. PMID:23002627

  9. Evaluation of redox mediators for amperometric biosensors: Ru-complex modified carbon-paste/enzyme electrodes.

    PubMed

    Ivanova, Ekaterina V; Sergeeva, Viktorya S; Oni, Joshua; Kurzawa, Christian; Ryabov, Alexander D; Schuhmann, Wolfgang

    2003-08-01

    The properties of reagentless amperometric biosensors are mainly governed by the interaction of the used redox enzyme and the redox mediators used to facilitate the electron-transfer reaction. Both the used redox mediators and the redox enzymes differ concerning their hydrophilicity and their properties within the matrix of a carbon-paste electrode. Since there is no general procedure which is applicable for any enzyme in combination with any redox mediator, optimisation is necessary for each possible combination. Three approaches for the development of biosensors were investigated using carbon-paste electrodes enriched with redox mediator as a base in all sensor architectures. A class of redox mediators with the common formula Ru(LL)(2)(X)(2) (where LL are 1,10-phenantroline or 2,2'-bipyridine type ligands, and X is an acido ligand) was investigated. In the first approach, enzymes were integrated into the carbon paste; in the second, the enzymes were adsorbed on the surface of the mediator-containing carbon-paste electrode and held in place by a Nafion film; and in the third approach, enzymes were entrapped in polymer films, which were electrochemically deposited onto the electrode's surface. The properties of the obtained biosensors strongly depend on the sensor architecture and the specific features of the used enzyme. Thus, our investigation using three different sensor architectures can provide valuable information about the possible interaction between a specific enzyme and a redox mediators with specific properties.

  10. A novel method to directionally stabilize enzymes together with redox mediators by electrodeposition.

    PubMed

    Shi, Wentao; Lin, Nansen; Song, Yilin; Liu, Chunxiu; Zhou, Shuai; Cai, Xinxia

    2014-01-15

    This paper depicts a novel method to directionally stabilize enzymes together with redox mediators by electrodeposition. Chitosan was used as a stabilizing matrix. By electrochemical removal of local H(+), chitosan close to working electrode became locally insoluble, and enzymes and redox mediators in chitosan were stabilized. The microelectrode on home-made microelectrode array (MEA) served as the working electrode. Three model enzymes--horseradish peroxidase (HRP), glucose oxidase (GOD), and glutamate oxidase (GlOD)--were used to fabricate different biosensors, and the redox mediator model was a poly(vinylpyridine) complex of Os(bpy)2Cl and a diepoxide (PVP-Os). Biosensors fabricated by the method exhibited very high performance. For HRP biosensor fabricated by this method, the sensitivity was 5.274 nA μM(-1) mm(-2), with linear detection range (LDR) of 2-220 μM and limit of detection (LOD) of 1 μM (S/N=3); for GOD biosensor, the sensitivity was 2.65 nA μM(-1) mm(-2), with LDR of 4-500 μM and LOD of 2 μM (S/N=3); for GlOD biosensor, the sensitivity was 0.33 nA μM(-1)mm(-2), with LDR of 4-500 μM and LOD of 2 μM (S/N=3). Since this method is very simple and especially suitable for directionally introducing enzymes and redox mediators onto microelectrode without contaminating other sites in the same microenvironment, it could be used for fabricating in vivo or in vitro 2nd generation biosensors in μm-scale, especially in neuroscience.

  11. Activated carbon as an electron acceptor and redox mediator during the anaerobic biotransformation of azo dyes.

    PubMed

    van der Zee, Frank P; Bisschops, Iemke A E; Lettinga, Gatze; Field, Jim A

    2003-01-15

    Activated carbon (AC) has a long history of applications in environmental technology as an adsorbent of pollutants for the purification of drinking waters and wastewaters. Here we describe novel role of AC as redox mediator in accelerating the reductive transformation of pollutants as well as a terminal electron acceptor in the biological oxidation of an organic substrate. This study explores the use of AC as an immobilized redox mediator for the reduction of a recalcitrant azo dye (hydrolyzed Reactive Red 2) in laboratory-scale anaerobic bioreactors, using volatile fatty acids as electron donor. The incorporation of AC in the sludge bed greatly improved dye removal and formation of aniline, a dye reduction product. These results indicate that AC acts as a redox mediator. In supporting batch experiments, bacteria were shown to oxidize acetate at the expense of reducing AC. Furthermore, AC greatly accelerated the chemical reduction of an azo dye by sulfide. The results taken as a whole clearly suggest that AC accepts electrons from the microbial oxidation of organic acids and transfers the electrons to azo dyes, accelerating their reduction. A possible role of quinone surface groups in the catalysis is discussed. PMID:12564915

  12. Influence of self-assembling redox mediators on charge transfer at hydrophobic electrodes.

    PubMed

    Smith, Timothy J; Wang, Chenxuan; Abbott, Nicholas L

    2015-10-01

    We report an investigation of the influence of reversible self-assembly of amphiphilic redox-mediators on interfacial charge transfer at chemically functionalized electrodes. Specifically, we employed (11-ferrocenylundecyl)-trimethylammonium bromide (FTMA) as a model self-assembling redox mediator and alkanethiol-modified gold films as hydrophobic electrodes. By performing cyclic voltammetry (CV, 10 mV/s) in aqueous solutions containing FTMA above its critical micellar concentration (CMC), we measured anodic (Ia) and cathodic (Ic) peak current densities of 18 ± 3 and 1.1 ± 0.1 μA/cm(2), respectively, revealing substantial current rectification (Ia/Ic= 17) at the hydrophobic electrodes. In contrast, hydroxymethyl ferrocene (a non-self-assembling redox mediator) at hydrophobic electrodes and FTMA at bare gold electrodes, yielded relatively low levels of rectification (Ia/Ic= 1.7 and 2.3, respectively). Scan-rate-dependent measurements revealed Ia of FTMA to arise largely from the diffusion of FTMA from bulk solution to the hydrophobic electrode whereas Ic was dominated by adsorbed FTMA, leading to the proposal that current rectification observed with FTMA is mediated by interfacial assemblies of reduced FTMA that block access of oxidized FTMA to the hydrophobic electrode. Support for this proposal was obtained by using atomic force microscopy and quartz crystal microbalance measurements to confirm the existence of interfacial assemblies of reduced FTMA (1.56 ± 0.2 molecules/nm(2)). Additional characterization of a mixed surfactant system containing FTMA and dodecyltrimethylammonium bromide (DTAB) revealed that interfacial assemblies of DTAB also block access of oxidized FTMA to hydrophobic electrodes; this system exhibited Ia/Ic > 80. These results and others reported in this paper suggest that current rectification occurs in this system because oxidized FTMA does not mix with interfacial assemblies of reduced FTMA or DTAB formed at hydrophobic electrodes. More

  13. Production of Cellobionate from Cellulose Using an Engineered Neurospora crassa Strain with Laccase and Redox Mediator Addition

    PubMed Central

    Hildebrand, Amanda; Kasuga, Takao; Fan, Zhiliang

    2015-01-01

    We report a novel production process for cellobionic acid from cellulose using an engineered fungal strain with the exogenous addition of laccase and a redox mediator. A previously engineered strain of Neurospora crassa (F5∆ace-1∆cre-1∆ndvB) was shown to produce cellobionate directly from cellulose without the addition of exogenous cellulases. Specifically, N. crassa produces cellulases, which hydrolyze cellulose to cellobiose, and cellobiose dehydrogenase (CDH), which oxidizes cellobiose to cellobionate. However, the conversion of cellobiose to cellobionate is limited by the slow re-oxidation of CDH by molecular oxygen. By adding low concentrations of laccase and a redox mediator to the fermentation, CDH can be efficiently oxidized by the redox mediator, with in-situ re-oxidation of the redox mediator by laccase. The conversion of cellulose to cellobionate was optimized by evaluating pH, buffer, and laccase and redox mediator addition time on the yield of cellobionate. Mass and material balances were performed, and the use of the native N. crassa laccase in such a conversion system was evaluated against the exogenous Pleurotus ostreatus laccase. This paper describes a working concept of cellobionate production from cellulose using the CDH-ATBS-laccase system in a fermentation system. PMID:25849253

  14. Aflatoxin B₁ and M₁ Degradation by Lac2 from Pleurotus pulmonarius and Redox Mediators.

    PubMed

    Loi, Martina; Fanelli, Francesca; Zucca, Paolo; Liuzzi, Vania C; Quintieri, Laura; Cimmarusti, Maria T; Monaci, Linda; Haidukowski, Miriam; Logrieco, Antonio F; Sanjust, Enrico; Mulè, Giuseppina

    2016-01-01

    Laccases (LCs) are multicopper oxidases that find application as versatile biocatalysts for the green bioremediation of environmental pollutants and xenobiotics. In this study we elucidate the degrading activity of Lac2 pure enzyme form Pleurotus pulmonarius towards aflatoxin B₁ (AFB₁) and M₁ (AFM₁). LC enzyme was purified using three chromatographic steps and identified as Lac2 through zymogram and LC-MS/MS. The degradation assays were performed in vitro at 25 °C for 72 h in buffer solution. AFB₁ degradation by Lac2 direct oxidation was 23%. Toxin degradation was also investigated in the presence of three redox mediators, (2,2'-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid]) (ABTS) and two naturally-occurring phenols, acetosyringone (AS) and syringaldehyde (SA). The direct effect of the enzyme and the mediated action of Lac2 with redox mediators univocally proved the correlation between Lac2 activity and aflatoxins degradation. The degradation of AFB₁ was enhanced by the addition of all mediators at 10 mM, with AS being the most effective (90% of degradation). AFM₁ was completely degraded by Lac2 with all mediators at 10 mM. The novelty of this study relies on the identification of a pure enzyme as capable of degrading AFB₁ and, for the first time, AFM₁, and on the evidence that the mechanism of an effective degradation occurs via the mediation of natural phenolic compounds. These results opened new perspective for Lac2 application in the food and feed supply chains as a biotransforming agent of AFB₁ and AFM₁. PMID:27563923

  15. Aflatoxin B1 and M1 Degradation by Lac2 from Pleurotus pulmonarius and Redox Mediators

    PubMed Central

    Loi, Martina; Fanelli, Francesca; Zucca, Paolo; Liuzzi, Vania C.; Quintieri, Laura; Cimmarusti, Maria T.; Monaci, Linda; Haidukowski, Miriam; Logrieco, Antonio F.; Sanjust, Enrico; Mulè, Giuseppina

    2016-01-01

    Laccases (LCs) are multicopper oxidases that find application as versatile biocatalysts for the green bioremediation of environmental pollutants and xenobiotics. In this study we elucidate the degrading activity of Lac2 pure enzyme form Pleurotus pulmonarius towards aflatoxin B1 (AFB1) and M1 (AFM1). LC enzyme was purified using three chromatographic steps and identified as Lac2 through zymogram and LC-MS/MS. The degradation assays were performed in vitro at 25 °C for 72 h in buffer solution. AFB1 degradation by Lac2 direct oxidation was 23%. Toxin degradation was also investigated in the presence of three redox mediators, (2,2′-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid]) (ABTS) and two naturally-occurring phenols, acetosyringone (AS) and syringaldehyde (SA). The direct effect of the enzyme and the mediated action of Lac2 with redox mediators univocally proved the correlation between Lac2 activity and aflatoxins degradation. The degradation of AFB1 was enhanced by the addition of all mediators at 10 mM, with AS being the most effective (90% of degradation). AFM1 was completely degraded by Lac2 with all mediators at 10 mM. The novelty of this study relies on the identification of a pure enzyme as capable of degrading AFB1 and, for the first time, AFM1, and on the evidence that the mechanism of an effective degradation occurs via the mediation of natural phenolic compounds. These results opened new perspective for Lac2 application in the food and feed supply chains as a biotransforming agent of AFB1 and AFM1. PMID:27563923

  16. Understanding the fundamentals of redox mediators in Li-O2 batteries: a case study on nitroxides.

    PubMed

    Bergner, Benjamin J; Hofmann, Christine; Schürmann, Adrian; Schröder, Daniel; Peppler, Klaus; Schreiner, Peter R; Janek, Jürgen

    2015-12-21

    The development of aprotic lithium-oxygen (Li-O2) batteries suffers from high charging overvoltages. Dissolved redox mediators, like nitroxides, providing increased energy efficiency and longer lifetime are promising tools to overcome this challenge. Since this auspicious concept is still in its infancy, the underlying chemical reactions as well as the impact of the different (electro)chemical parameters are poorly understood. Herein, we derive an electrochemical model for the charging reactions, which is validated by potentiostatic measurements. The model elucidates the impact of the major factors including basic cell parameters and the chemical properties of the redox mediator. The model is applied to the promising class of nitroxides, which is systematically investigated by using derivatives of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy), AZADO (2-azaadamantane-N-oxyl), and an azaphenalene based nitroxide. The nitroxides are electrochemically characterized by cyclic voltammetry and their performance as redox mediators is studied in Li-O2 batteries with an ether-based electrolyte. Based on the presented model, the charging profiles of the different nitroxide redox mediators are correlated with their molecular structures.

  17. Production of cellobionate from cellulose using an engineered Neurospora crassa strain with laccase and redox mediator addition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report a novel production process for cellobionic acid from cellulose using an engineered fungal strain with the exogenous addition of laccase and a redox mediator. A previously engineered strain of Neurospora crassa (F5'ace-1'cre-1'ndvB) was shown to produce cellobionate directly from cellulose ...

  18. Understanding the fundamentals of redox mediators in Li-O2 batteries: a case study on nitroxides.

    PubMed

    Bergner, Benjamin J; Hofmann, Christine; Schürmann, Adrian; Schröder, Daniel; Peppler, Klaus; Schreiner, Peter R; Janek, Jürgen

    2015-12-21

    The development of aprotic lithium-oxygen (Li-O2) batteries suffers from high charging overvoltages. Dissolved redox mediators, like nitroxides, providing increased energy efficiency and longer lifetime are promising tools to overcome this challenge. Since this auspicious concept is still in its infancy, the underlying chemical reactions as well as the impact of the different (electro)chemical parameters are poorly understood. Herein, we derive an electrochemical model for the charging reactions, which is validated by potentiostatic measurements. The model elucidates the impact of the major factors including basic cell parameters and the chemical properties of the redox mediator. The model is applied to the promising class of nitroxides, which is systematically investigated by using derivatives of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy), AZADO (2-azaadamantane-N-oxyl), and an azaphenalene based nitroxide. The nitroxides are electrochemically characterized by cyclic voltammetry and their performance as redox mediators is studied in Li-O2 batteries with an ether-based electrolyte. Based on the presented model, the charging profiles of the different nitroxide redox mediators are correlated with their molecular structures. PMID:26563563

  19. Decolorization of direct dyes by salt fractionated turnip proteins enhanced in the presence of hydrogen peroxide and redox mediators.

    PubMed

    Matto, Mahreen; Husain, Qayyum

    2007-09-01

    The present paper demonstrates the effect of salt fractionated turnip (Brassica rapa) proteins on the decolorization of direct dyes, used in textile industry, in the presence of various redox mediators. The rate and extent of decolorization of dyes was significantly enhanced by the presence of different types of redox mediators. Six out of 10 investigated compounds have shown their potential in enhancing the decolorization of direct dyes. The performance was evaluated at different concentrations of mediator and enzyme. The efficiency of each natural mediator depends on the type of dye treated. The decolorization of all tested direct dyes was maximum in the presence of 0.6mM redox mediator at pH 5.5 and 30 degrees C. Complex mixtures of dyes were also maximally decolorized in the presence of 0.6mM redox mediator (1-hydroxybenzotriazole/violuric acid). In order to examine the operational stability of the enzyme preparation, the enzyme was exploited for the decolorization of mixtures of dyes for different times in a stirred batch process. There was no further change in decolorization of an individual dye or their mixtures after 60 min; the enzyme caused more than 80% decolorization of all dyes in the presence of 1-hydroxybenzotriazole/violuric acid. However, there was no desirable increase in dye decolorization of the mixtures on overnight stay. Total organic carbon analysis of treated dyes or their mixtures showed that these results were quite comparable to the loss of color from solutions. However, the treatment of such polluted water in the presence of redox mediators caused the formation of insoluble precipitate, which could be removed by the process of centrifugation. The results suggested that catalyzed oxidative coupling reactions might be important for natural transformation pathways for dyes and indicate their potential use as an efficient means for removal of dyes color from waters and wastewaters.

  20. A Highly Active Low Voltage Redox Mediator for Enhanced Rechargeability of Lithium-Oxygen Batteries.

    PubMed

    Kundu, Dipan; Black, Robert; Adams, Brian; Nazar, Linda F

    2015-12-23

    Owing to its high theoretical specific energy, the Li-oxygen battery is one of the fundamentally most promising energy storage systems, but also one of the most challenging. Poor rechargeability, involving the oxidation of insoluble and insulating lithium peroxide (Li2O2), has remained the "Achilles' heel" of this electrochemical energy storage system. We report here on a new redox mediator tris[4-(diethylamino)phenyl]amine (TDPA), that-at 3.1 V-exhibits the lowest and closest potential redox couple compared to the equilibrium voltage of the Li-oxygen cell of those reported to date, with a second couple also at a low potential of 3.5 V. We show it is a soluble "catalyst" capable of lowering the Li2O2 charging potential by >0.8 V without requiring direct electrical contact of the peroxide and that it also facilitates high discharge capacities. Its chemical and electrochemical stability, fast diffusion kinetics, and two dynamic redox potentials represent a significant advance in oxygen-evolution catalysis. It enables Li-O2 cells that can be recharged more than 100 cycles with average round-trip efficiencies >80%, opening a new avenue for practical Li-oxygen batteries.

  1. Effects of redox mediators on azo dye decolorization by Shewanella algae under saline conditions.

    PubMed

    Meng, Xianming; Liu, Guangfei; Zhou, Jiti; Fu, Q Shiang

    2014-01-01

    Azo dye decolorization by Shewanella algae (SAL) in the presence of high concentrations of NaCl and different quinones or humic acids was investigated to reveal the effects of redox mediator under saline conditions. Growth of SAL and the other two marine Shewanella strains coupled to anthraquinone-2,6-disulfonate (AQDS) reduction was observed in a wide range of NaCl concentrations (0-7%). AQDS showed the best enhancing effects, whereas some other quinones demonstrated poorer stimulating or even inhibiting effects on acid red 27 (AR27) decolorization. Different humic acids could also enhance the decolorization. The correlation between specific AQDS-mediated reduction rate and initial AR27 concentration could be described with Michaelis-Menten kinetics (Km=0.2 mM and Vmax=9.3 μmol mg cell(-1) h(-1)). AQDS reduction by SAL was determined to be the rate-limiting step of mediated reduction. Mediated decolorization products of AR27 were determined to be less phytotoxic aromatic amines.

  2. A Highly Active Low Voltage Redox Mediator for Enhanced Rechargeability of Lithium–Oxygen Batteries

    PubMed Central

    2015-01-01

    Owing to its high theoretical specific energy, the Li-oxygen battery is one of the fundamentally most promising energy storage systems, but also one of the most challenging. Poor rechargeability, involving the oxidation of insoluble and insulating lithium peroxide (Li2O2), has remained the “Achilles’ heel” of this electrochemical energy storage system. We report here on a new redox mediator tris[4-(diethylamino)phenyl]amine (TDPA), that—at 3.1 V—exhibits the lowest and closest potential redox couple compared to the equilibrium voltage of the Li-oxygen cell of those reported to date, with a second couple also at a low potential of 3.5 V. We show it is a soluble “catalyst” capable of lowering the Li2O2 charging potential by >0.8 V without requiring direct electrical contact of the peroxide and that it also facilitates high discharge capacities. Its chemical and electrochemical stability, fast diffusion kinetics, and two dynamic redox potentials represent a significant advance in oxygen-evolution catalysis. It enables Li–O2 cells that can be recharged more than 100 cycles with average round-trip efficiencies >80%, opening a new avenue for practical Li-oxygen batteries. PMID:27163015

  3. Effects of Protonation State on a Tyrosine-Histidine Bioinspired Redox Mediator

    SciTech Connect

    Moore, Gary F.; Hambourger, Michael; Kodis, Gerdenis; Michl, Weston; Gust, Devens; Moore, Thomas A.; Moore, Ana L.

    2010-11-18

    The conversion of tyrosine to the corresponding tyrosyl radical in photosytem II (PSII) is an example of proton-coupled electron transfer. Although the tyrosine moiety (TyrZ) is known to function as a redox mediator between the photo-oxidized primary donor (P680 •+) and the Mn-containing oxygen-evolving complex, the protonation states involved in the course of the reaction remain an active area of investigation. Herein, we report on the optical, structural, and electrochemical properties of tyrosine-histidine constructs, which model the function of their naturally occurring counterparts in PSII. Electrochemical studies show that the phenoxyl/phenol couple of the model is chemically reversible and thermodynamically capable of water oxidation. Studies under acidic and basic conditions provide clear evidence that an ionizable proton controls the electrochemical potential of the tyrosine-histidine mimic and that an exogenous base or acid can be used to generate a low-potential or high-potential mediator, respectively. The phenoxyl/phenoxide couple associated with the low-potential mediator is thermodynamically incapable of water oxidation, whereas the relay associated with the high-potential mediator is thermodynamically incapable of reducing an attached photoexcited porphyrin. These studies provide insight regarding the mechanistic role of the tyrosine-histidine complex in water oxidation and strategies for making use of hydrogen bonds to affect the coupling between proton and electron transfer in artificial photosynthetic systems.

  4. Rational design of redox mediators for advanced Li-O2 batteries

    NASA Astrophysics Data System (ADS)

    Lim, Hee-Dae; Lee, Byungju; Zheng, Yongping; Hong, Jihyun; Kim, Jinsoo; Gwon, Hyeokjo; Ko, Youngmin; Lee, Minah; Cho, Kyeongjae; Kang, Kisuk

    2016-06-01

    The discovery of effective catalysts is an important step towards achieving Li-O2 batteries with long cycle life and high round-trip efficiency. Soluble-type catalysts or redox mediators (RMs) possess great advantages over conventional solid catalysts, generally exhibiting much higher efficiency. Here, we select a series of organic RM candidates as a model system to identify the key descriptor in determining the catalytic activities and stabilities in Li-O2 cells. It is revealed that the level of ionization energies, readily available parameters from a database of the molecules, can serve such a role when comparing with the formation energy of Li2O2 and the highest occupied molecular orbital energy of the electrolyte. It is demonstrated that they are critical in reducing the overpotential and improving the stability of Li-O2 cells, respectively. Accordingly, we propose a general principle for designing feasible catalysts and report a RM, dimethylphenazine, with a remarkably low overpotential and high stability.

  5. The accelerating effect and mechanism of a newly functional bio-carrier modified by redox mediators for the azo dyes decolorization.

    PubMed

    Guo, Jianbo; Kang, Li; Lian, Jing; Yang, Jingliang; Yan, Bin; Li, Zaixing; Liu, Chun; Yue, Lin

    2010-11-01

    In this study, a functional bio-carrier modified by redox meditors was developed as a redox mediator for application in azo dye decolorization processes. Its accelerating effect and mechanism for azo dyes decolorization were also examined. The decolorization rates of 10 azo dyes were enhanced about 1.5-3 fold by the functional bio-carrier modified with disperse turquoise blue S-GL, and the ORP value during the acid red GR decolorization process was changed to a more negative value of 20-25 mV. Non-dissolved redox mediator on the functional bio-carrier played a similar role as NADH during the azo dyes decolorization process. At the same time, the functional bio-carrier exhibited good reusability and the combinational technology of the redox mediator and bio-carrier was a great improvement of the redox mediator application and represents a new bio-treatment concept.

  6. Characteristics and Kinetic Analysis of AQS Transformation and Microbial Goethite Reduction:Insight into "Redox mediator-Microbe-Iron oxide" Interaction Process.

    PubMed

    Zhu, Weihuang; Shi, Mengran; Yu, Dan; Liu, Chongxuan; Huang, Tinglin; Wu, Fengchang

    2016-01-01

    The characteristics and kinetics of redox transformation of a redox mediator, anthraquinone-2-sulfonate (AQS), during microbial goethite reduction by Shewanella decolorationis S12, a dissimilatory iron reduction bacterium (DIRB), were investigated to provide insights into "redox mediator-iron oxide" interaction in the presence of DIRB. Two pre-incubation reaction systems of the "strain S12- goethite" and the "strain S12-AQS" were used to investigate the dynamics of goethite reduction and AQS redox transformation. Results show that the concentrations of goethite and redox mediator, and the inoculation cell density all affect the characteristics of microbial goethite reduction, kinetic transformation between oxidized and reduced species of the redox mediator. Both abiotic and biotic reactions and their coupling regulate the kinetic process for "Quinone-Iron" interaction in the presence of DIRB. Our results provide some new insights into the characteristics and mechanisms of interaction among "quinone-DIRB- goethite" under biotic/abiotic driven.

  7. Redox-mediated activation of latent transforming growth factor-beta 1

    NASA Technical Reports Server (NTRS)

    Barcellos-Hoff, M. H.; Dix, T. A.; Chatterjee, A. (Principal Investigator)

    1996-01-01

    Transforming growth factor beta 1 (TGF beta) is a multifunctional cytokine that orchestrates response to injury via ubiquitous cell surface receptors. The biological activity of TGF beta is restrained by its secretion as a latent complex (LTGF beta) such that activation determines the extent of TGF beta activity during physiological and pathological events. TGF beta action has been implicated in a variety of reactive oxygen-mediated tissue processes, particularly inflammation, and in pathologies such as reperfusion injury, rheumatoid arthritis, and atherosclerosis. It was recently shown to be rapidly activated after in vivo radiation exposure, which also generates reactive oxygen species (ROS). In the present studies, the potential for redox-mediated LTGF beta activation was investigated using a cell-free system in which ROS were generated in solution by ionizing radiation or metal ion-catalyzed ascorbate reaction. Irradiation (100 Gray) of recombinant human LTGF beta in solution induced 26% activation compared with that elicited by standard thermal activation. Metal-catalyzed ascorbate oxidation elicited extremely efficient recombinant LTGF beta activation that matched or exceeded thermal activation. The efficiency of ascorbate activation depended on ascorbate concentrations and the presence of transition metal ions. We postulate that oxidation of specific amino acids in the latency-conferring peptide leads to a conformation change in the latent complex that allows release of TGF beta. Oxidative activation offers a novel route for the involvement of TGF beta in tissue processes in which ROS are implicated and endows LTGF beta with the ability to act as a sensor of oxidative stress and, by releasing TGF beta, to function as a signal for orchestrating the response of multiple cell types. LTGF beta redox sensitivity is presumably directed toward recovery of homeostasis; however, oxidation may also be a mechanism of LTGF beta activation that can be deleterious during

  8. Potentials of high-temperature anaerobic treatment and redox mediators for the reductive decolorization of azo dyes from textile wastewaters.

    PubMed

    Dos Santos, A B; Cervantes, F J; van Lier, J B

    2006-01-01

    The discharge of dye-colored wastewaters in surface water represents a serious environmental problem because it may decrease the water transparency, therefore having an effect on photosynthesis, and a public health concern because dyes and their reducing products are carcinogenic. In recent years, big achievements have been made in the use of anaerobic granular sludge not only on colored wastewaters but also on the detoxification of other xenobiotics compounds. This paper compiles some important findings related to the potentials of high-temperature anaerobic treatment and redox mediators on the reductive decolorization of azo dyes from textile wastewaters.

  9. Discharging a Li-S battery with ultra-high sulphur content cathode using a redox mediator.

    PubMed

    Kim, Kwi Ryong; Lee, Kug-Seung; Ahn, Chi-Yeong; Yu, Seung-Ho; Sung, Yung-Eun

    2016-01-01

    Lithium-sulphur batteries are under intense research due to the high specific capacity and low cost. However, several problems limit their commercialization. One of them is the insulating nature of sulphur, which necessitates a large amount of conductive agent and binder in the cathode, reducing the effective sulphur load as well as the energy density. Here we introduce a redox mediator, cobaltocene, which acts as an electron transfer agent between the conductive surface and the polysulphides in the electrolyte. We confirmed that cobaltocene could effectively convert polysulphides to Li2S using scanning electron microscope, X-ray absorption near-edge structure and in-situ X-ray diffraction studies. This redox mediator enabled excellent electrochemical performance in a cathode with ultra-high sulphur content (80 wt%). It delivered 400 mAh g(-1)cathode capacity after 50 cycles, which is equivalent to 800 mAh g(-1)S in a typical cathode with 50 wt% sulphur. Furthermore, the volumetric capacity was also dramatically improved. PMID:27573528

  10. Discharging a Li-S battery with ultra-high sulphur content cathode using a redox mediator

    PubMed Central

    Kim, Kwi Ryong; Lee, Kug-Seung; Ahn, Chi-Yeong; Yu, Seung-Ho; Sung, Yung-Eun

    2016-01-01

    Lithium-sulphur batteries are under intense research due to the high specific capacity and low cost. However, several problems limit their commercialization. One of them is the insulating nature of sulphur, which necessitates a large amount of conductive agent and binder in the cathode, reducing the effective sulphur load as well as the energy density. Here we introduce a redox mediator, cobaltocene, which acts as an electron transfer agent between the conductive surface and the polysulphides in the electrolyte. We confirmed that cobaltocene could effectively convert polysulphides to Li2S using scanning electron microscope, X-ray absorption near-edge structure and in-situ X-ray diffraction studies. This redox mediator enabled excellent electrochemical performance in a cathode with ultra-high sulphur content (80 wt%). It delivered 400 mAh g−1cathode capacity after 50 cycles, which is equivalent to 800 mAh g−1S in a typical cathode with 50 wt% sulphur. Furthermore, the volumetric capacity was also dramatically improved. PMID:27573528

  11. Enzyme mediated synthesis of polypyrrole in the presence of chondroitin sulfate and redox mediators of natural origin.

    PubMed

    Grijalva-Bustamante, G A; Evans-Villegas, A G; del Castillo-Castro, T; Castillo-Ortega, M M; Cruz-Silva, R; Huerta, F; Morallón, E

    2016-06-01

    Polypyrrole (PPy) was synthesized by enzyme mediated oxidation of pyrrole using naturally occurring compounds as redox mediators. The catalytic mechanism is an enzymatic cascade reaction in which hydrogen peroxide is the oxidizer and soybean peroxidase, in the presence of acetosyringone, syringaldehyde or vanillin, acts as a natural catalysts. The effect of the initial reaction composition on the polymerization yield and electrical conductivity of PPy was analyzed. Morphology of the PPy particles was studied by scanning electron microscopy and transmission electron microscopy whereas the chemical structure was studied by X-ray photoelectron and Fourier transformed infrared spectroscopic techniques. The redox mediators increased the polymerization yield without a significant modification of the electronic structure of PPy. The highest conductivity of PPy was reached when chondroitin sulfate was used simultaneously as dopant and template during pyrrole polymerization. Electroactive properties of PPy obtained from natural precursors were successfully used in the amperometric quantification of uric acid concentrations. PPy increases the amperometric sensitivity of carbon nanotube screen-printed electrodes toward uric acid detection. PMID:27040261

  12. Discharging a Li-S battery with ultra-high sulphur content cathode using a redox mediator

    NASA Astrophysics Data System (ADS)

    Kim, Kwi Ryong; Lee, Kug-Seung; Ahn, Chi-Yeong; Yu, Seung-Ho; Sung, Yung-Eun

    2016-08-01

    Lithium-sulphur batteries are under intense research due to the high specific capacity and low cost. However, several problems limit their commercialization. One of them is the insulating nature of sulphur, which necessitates a large amount of conductive agent and binder in the cathode, reducing the effective sulphur load as well as the energy density. Here we introduce a redox mediator, cobaltocene, which acts as an electron transfer agent between the conductive surface and the polysulphides in the electrolyte. We confirmed that cobaltocene could effectively convert polysulphides to Li2S using scanning electron microscope, X-ray absorption near-edge structure and in-situ X-ray diffraction studies. This redox mediator enabled excellent electrochemical performance in a cathode with ultra-high sulphur content (80 wt%). It delivered 400 mAh g-1cathode capacity after 50 cycles, which is equivalent to 800 mAh g-1S in a typical cathode with 50 wt% sulphur. Furthermore, the volumetric capacity was also dramatically improved.

  13. Polymer Electrolyte Fuel Cells Employing Heteropolyacids as Redox Mediators for Oxygen Reduction Reactions: Pt-Free Cathode Systems.

    PubMed

    Matsui, Toshiaki; Morikawa, Eri; Nakada, Shintaro; Okanishi, Takeou; Muroyama, Hiroki; Hirao, Yoshifumi; Takahashi, Tsuyoshi; Eguchi, Koichi

    2016-07-20

    In this study, the heteropolyacids of H3+xPVxMO12-xO40 (x = 0, 2, and 3) were applied as redox mediators for the oxygen reduction reaction in polymer electrolyte fuel cells, of which the cathode is free from the usage of noble metals such as Pt/C. In this system, the electrochemical reduction of heteropolyacid over the carbon cathode and the subsequent reoxidation of the partially reduced heteropolyacid by exposure to the dissolved oxygen in the regenerator are important processes for continuous power generation. Thus, the redox properties of catholytes containing these heteropolyacids were investigated in detail. The substitution quantity of V in the heteropolyacid affected the onset reduction potential as well as the reduction current density, resulting in a difference in cell performance. The chemical composition of heteropolyacid also had a significant impact on the reoxidation property. Among the three compounds, H6PV3Mo9O40 was the most suitable redox mediator. Furthermore, the pH of the catholyte was found to be the crucial factor in determining the reoxidation rate of partially reduced heteropolyacid as well as cell performance.

  14. Enzyme mediated synthesis of polypyrrole in the presence of chondroitin sulfate and redox mediators of natural origin.

    PubMed

    Grijalva-Bustamante, G A; Evans-Villegas, A G; del Castillo-Castro, T; Castillo-Ortega, M M; Cruz-Silva, R; Huerta, F; Morallón, E

    2016-06-01

    Polypyrrole (PPy) was synthesized by enzyme mediated oxidation of pyrrole using naturally occurring compounds as redox mediators. The catalytic mechanism is an enzymatic cascade reaction in which hydrogen peroxide is the oxidizer and soybean peroxidase, in the presence of acetosyringone, syringaldehyde or vanillin, acts as a natural catalysts. The effect of the initial reaction composition on the polymerization yield and electrical conductivity of PPy was analyzed. Morphology of the PPy particles was studied by scanning electron microscopy and transmission electron microscopy whereas the chemical structure was studied by X-ray photoelectron and Fourier transformed infrared spectroscopic techniques. The redox mediators increased the polymerization yield without a significant modification of the electronic structure of PPy. The highest conductivity of PPy was reached when chondroitin sulfate was used simultaneously as dopant and template during pyrrole polymerization. Electroactive properties of PPy obtained from natural precursors were successfully used in the amperometric quantification of uric acid concentrations. PPy increases the amperometric sensitivity of carbon nanotube screen-printed electrodes toward uric acid detection.

  15. Polymer Electrolyte Fuel Cells Employing Heteropolyacids as Redox Mediators for Oxygen Reduction Reactions: Pt-Free Cathode Systems.

    PubMed

    Matsui, Toshiaki; Morikawa, Eri; Nakada, Shintaro; Okanishi, Takeou; Muroyama, Hiroki; Hirao, Yoshifumi; Takahashi, Tsuyoshi; Eguchi, Koichi

    2016-07-20

    In this study, the heteropolyacids of H3+xPVxMO12-xO40 (x = 0, 2, and 3) were applied as redox mediators for the oxygen reduction reaction in polymer electrolyte fuel cells, of which the cathode is free from the usage of noble metals such as Pt/C. In this system, the electrochemical reduction of heteropolyacid over the carbon cathode and the subsequent reoxidation of the partially reduced heteropolyacid by exposure to the dissolved oxygen in the regenerator are important processes for continuous power generation. Thus, the redox properties of catholytes containing these heteropolyacids were investigated in detail. The substitution quantity of V in the heteropolyacid affected the onset reduction potential as well as the reduction current density, resulting in a difference in cell performance. The chemical composition of heteropolyacid also had a significant impact on the reoxidation property. Among the three compounds, H6PV3Mo9O40 was the most suitable redox mediator. Furthermore, the pH of the catholyte was found to be the crucial factor in determining the reoxidation rate of partially reduced heteropolyacid as well as cell performance. PMID:27348019

  16. Continuous glucose monitoring microsensor with a nanoscale conducting matrix and redox mediator

    NASA Astrophysics Data System (ADS)

    Pesantez, Daniel

    vitro testing for glucose shows increasing current with increasing analyte concentration. Testing the glucose microsensor with known concentrations of glucose over a period of 48 hours demonstrated both the potential durability and sensitivity of the device. Unknown/blind in vitro glucose experiments showed the reproducibility and accuracy of the microsensor to detect various glucose levels. Thinner polymer matrix films lead to better sensing performance during in vitro tests (0.6nA/mM lower limit sensitivity and 0.2nA/mM upper limit sensitivity). In vitro experiments using electroactive ascorbic acid (AA) and uric acid (UA) showed the selectivity of the sensor for glucose. In an effort to reduce the sensor's oxidation potential (0.7V) and noise, a second generation electron transfer approach was developed by incorporating into a modified Platinum WE with a nanoscale PPy and GOx matrix, a redox mediator. Ferrocene (Fc) was selected as the artificial electron carrier, substituting molecular oxygen in the enzymatic reaction. The incorporation of Fc into the polymer matrix is done by a simple electrochemical synthesis. Modifications in the microsensor design, materials and fabrication process are presented. Experiments with the new sensor generation resulted in higher sensitivity values (22.8nA/mM lower limit sensitivity and 12.5nA/mM upper limit sensitivity) for glucose and noise was further eliminated by operating the sensor at a lower oxidation potential (0.3V). The final experimental work consisted of preliminary ex vivo tests with the MetaSense microdevice on bovine kidney samples, which showed a qualitatively correlation between glucose consumption trend profile during preservation and viability histology outcome.

  17. Exploring redox-mediating characteristics of textile dye-bearing microbial fuel cells: thionin and malachite green.

    PubMed

    Chen, Bor-Yann; Xu, Bin; Qin, Lian-Jie; Lan, John Chi-Wei; Hsueh, Chung-Chuan

    2014-10-01

    Prior studies indicated that biodecolorized intermediates of azo dyes could act as electron shuttles to stimulate wastewater decolorization and bioelectricity generation (WD&BG) in microbial fuel cells (MFCs). This study tended to explore whether non-azo textile dyes (i.e., thionin and malachite green) could also own such redox-mediating capabilities for WD&BG. Prior findings mentioned that OH and/or NH2 substitute-containing auxochrome compounds (e.g., 2-aminophenol and 1,2-dihydroxybenzene) could effectively mediate electron transport in MFCs for simultaneous WD&BG. This work clearly suggested that the presence of electron-mediating textile dyes (e.g., thionin and malachite green (MG)) in MFCs is promising to stimulate color removal and bioelectricity generation. That is, using MFCs as operation strategy for wastewater biodecolorization is economically promising in industrial applications due to autocatalytic acceleration of electron-flux for WD&BG in MFCs.

  18. Exploring redox-mediating characteristics of textile dye-bearing microbial fuel cells: thionin and malachite green.

    PubMed

    Chen, Bor-Yann; Xu, Bin; Qin, Lian-Jie; Lan, John Chi-Wei; Hsueh, Chung-Chuan

    2014-10-01

    Prior studies indicated that biodecolorized intermediates of azo dyes could act as electron shuttles to stimulate wastewater decolorization and bioelectricity generation (WD&BG) in microbial fuel cells (MFCs). This study tended to explore whether non-azo textile dyes (i.e., thionin and malachite green) could also own such redox-mediating capabilities for WD&BG. Prior findings mentioned that OH and/or NH2 substitute-containing auxochrome compounds (e.g., 2-aminophenol and 1,2-dihydroxybenzene) could effectively mediate electron transport in MFCs for simultaneous WD&BG. This work clearly suggested that the presence of electron-mediating textile dyes (e.g., thionin and malachite green (MG)) in MFCs is promising to stimulate color removal and bioelectricity generation. That is, using MFCs as operation strategy for wastewater biodecolorization is economically promising in industrial applications due to autocatalytic acceleration of electron-flux for WD&BG in MFCs. PMID:25062539

  19. Redox-Mediated Indirect Fluorescence Immunoassay for the Detection of Disease Biomarkers Using Dopamine-Functionalized Quantum Dots.

    PubMed

    Zhang, Wen-Hui; Ma, Wei; Long, Yi-Tao

    2016-05-17

    Here, we report a redox-mediated indirect fluorescence immunoassay (RMFIA) for the detection of the disease biomarker α-fetoprotein (AFP) using dopamine (DA)-functionalized CdSe/ZnS quantum dots (QDs). In this immunoassay, tyrosinase was conjugated with the detection antibody and acted as a bridge connecting the fluorescence signals of the QDs with the concentration of the disease biomarkers. The tyrosinase label used for RMFIA catalyzed the enzymatic oxidation of DAs on the surface of functionalized QDs and caused fluorescence quenching in the presence of the analyte. Using this technique, we obtained a limit of detection as low as 10 pM for AFP. This assay's potential for clinical analysis was demonstrated by detecting the real sera of patients with hepatocellular carcinoma (HCC). This study makes the first use of RMFIA for the rapid detection of AFP, opening up a new pathway for the detection of disease biomarkers.

  20. Study the biocatalyzing effect and mechanism of cellulose acetate immobilized redox mediators technology (CE-RM) on nitrite denitrification.

    PubMed

    Li, Haibo; Guo, Jianbo; Lian, Jing; Xi, Zhenhua; Zhao, Lijun; Liu, Xiaoyu; Zhang, Chenxiao; Yang, Jingliang

    2014-06-01

    The biocatalyzing effect of a novel cellulose acetate immobilized redox mediators technology (CE-RM) on nitrite denitrification process was studied with anthraquinone, 1,8-dichloroanthraquinone, 1,5-dichloroanthraquinone and 1,4,5,8-tetrachloroanthraquinone. The results showed that the immobilized 1,4,5,8-tetrachloroanthraquinone presented the best biocatalyzed effect which increased nitrite denitrification rate to 2.3-fold with 12 mmol/L 1,4,5,8-tetrachloroanthraquinone. The unequal biocatalyzing effect was due to the quantity and position of -Cl substituent in anthraquinone-structure. Moreover, the nitrite denitrification rate was increased with the oxidation reduction potential (ORP) values becoming more negative during the biocatalyzing process. The stabilized ORP value with 12 mmol/L immobilized 1,4,5,8-tetrachloroanthraquinone were 81 mV lower than the control. At the same time, the more OH(-) was produced with the higher nitrite removal rate achieved in the nitrite denitrification process. In addition, a positive linear correlation was found between the nitrite removal reaction constants k [gNO2(-)-N/(gVSS d)] and immobilized 1,4,5,8-tetrachloroanthraquinone concentration (C1,4,5,8-tetrachloroanthraquinone), which was k = 1.8443 C1,4,5,8-tetrachloroanthraquinone + 33.75(R(2) = 0.9411). The initial nitrite concentration of 179 mgNO2(-)-N/L resulted in the maximum nitrite removal rate, which was 6.526[gNO2(-)-N/(gVSS d)]. These results show that the application of cellulose acetate immobilized redox mediators (CE-RM) can be valuable for increasing nitrite denitrification rate.

  1. Characteristics and Kinetic Analysis of AQS Transformation and Microbial Goethite Reduction:Insight into “Redox mediator-Microbe-Iron oxide” Interaction Process

    NASA Astrophysics Data System (ADS)

    Zhu, Weihuang; Shi, Mengran; Yu, Dan; Liu, Chongxuan; Huang, Tinglin; Wu, Fengchang

    2016-03-01

    The characteristics and kinetics of redox transformation of a redox mediator, anthraquinone-2-sulfonate (AQS), during microbial goethite reduction by Shewanella decolorationis S12, a dissimilatory iron reduction bacterium (DIRB), were investigated to provide insights into “redox mediator-iron oxide” interaction in the presence of DIRB. Two pre-incubation reaction systems of the “strain S12- goethite” and the “strain S12-AQS” were used to investigate the dynamics of goethite reduction and AQS redox transformation. Results show that the concentrations of goethite and redox mediator, and the inoculation cell density all affect the characteristics of microbial goethite reduction, kinetic transformation between oxidized and reduced species of the redox mediator. Both abiotic and biotic reactions and their coupling regulate the kinetic process for “Quinone-Iron” interaction in the presence of DIRB. Our results provide some new insights into the characteristics and mechanisms of interaction among “quinone-DIRB- goethite” under biotic/abiotic driven.

  2. Aging exacerbates hypertension-induced cerebral microhemorrhages in mice: role of resveratrol treatment in vasoprotection

    PubMed Central

    Toth, Peter; Tarantini, Stefano; Springo, Zsolt; Tucsek, Zsuzsanna; Gautam, Tripti; Giles, Cory B; Wren, Jonathan D; Koller, Akos; Sonntag, William E; Csiszar, Anna; Ungvari, Zoltan

    2015-01-01

    Recent studies demonstrate that aging exacerbates hypertension-induced cognitive decline, but the specific age-related mechanisms remain elusive. Cerebral microhemorrhages (CMHs) are associated with rupture of small intracerebral vessels and are thought to progressively impair neuronal function. To determine whether aging exacerbates hypertension-induced CMHs young (3 months) and aged (24 months) mice were treated with angiotensin II plus L-NAME. We found that the same level of hypertension leads to significantly earlier onset and increased incidence of CMHs in aged mice than in young mice, as shown by neurological examination, gait analysis, and histological assessment of CMHs in serial brain sections. Hypertension-induced cerebrovascular oxidative stress and redox-sensitive activation of matrix metalloproteinases (MMPs) were increased in aging. Treatment of aged mice with resveratrol significantly attenuated hypertension-induced oxidative stress, inhibited vascular MMP activation, significantly delayed the onset, and reduced the incidence of CMHs. Collectively, aging promotes CMHs in mice likely by exacerbating hypertension-induced oxidative stress and MMP activation. Therapeutic strategies that reduce microvascular oxidative stress and MMP activation may be useful for the prevention of CMHs, protecting neurocognitive function in high-risk elderly patients. PMID:25677910

  3. Aging exacerbates hypertension-induced cerebral microhemorrhages in mice: role of resveratrol treatment in vasoprotection.

    PubMed

    Toth, Peter; Tarantini, Stefano; Springo, Zsolt; Tucsek, Zsuzsanna; Gautam, Tripti; Giles, Cory B; Wren, Jonathan D; Koller, Akos; Sonntag, William E; Csiszar, Anna; Ungvari, Zoltan

    2015-06-01

    Recent studies demonstrate that aging exacerbates hypertension-induced cognitive decline, but the specific age-related mechanisms remain elusive. Cerebral microhemorrhages (CMHs) are associated with rupture of small intracerebral vessels and are thought to progressively impair neuronal function. To determine whether aging exacerbates hypertension-induced CMHs young (3 months) and aged (24 months) mice were treated with angiotensin II plus L-NAME. We found that the same level of hypertension leads to significantly earlier onset and increased incidence of CMHs in aged mice than in young mice, as shown by neurological examination, gait analysis, and histological assessment of CMHs in serial brain sections. Hypertension-induced cerebrovascular oxidative stress and redox-sensitive activation of matrix metalloproteinases (MMPs) were increased in aging. Treatment of aged mice with resveratrol significantly attenuated hypertension-induced oxidative stress, inhibited vascular MMP activation, significantly delayed the onset, and reduced the incidence of CMHs. Collectively, aging promotes CMHs in mice likely by exacerbating hypertension-induced oxidative stress and MMP activation. Therapeutic strategies that reduce microvascular oxidative stress and MMP activation may be useful for the prevention of CMHs, protecting neurocognitive function in high-risk elderly patients. PMID:25677910

  4. Three-Dimensional Growth of Li2S in Lithium-Sulfur Batteries Promoted by a Redox Mediator.

    PubMed

    Gerber, Laura C H; Frischmann, Peter D; Fan, Frank Y; Doris, Sean E; Qu, Xiaohui; Scheuermann, Angelique M; Persson, Kristin; Chiang, Yet-Ming; Helms, Brett A

    2016-01-13

    During the discharge of a lithium-sulfur (Li-S) battery, an electronically insulating 2D layer of Li2S is electrodeposited onto the current collector. Once the current collector is enveloped, the overpotential of the cell increases, and its discharge is arrested, often before reaching the full capacity of the active material. Guided by a new computational platform known as the Electrolyte Genome, we advance and apply benzo[ghi]peryleneimide (BPI) as a redox mediator for the reduction of dissolved polysulfides to Li2S. With BPI present, we show that it is now possible to electrodeposit Li2S as porous, 3D deposits onto carbon current collectors during cell discharge. As a result, sulfur utilization improved 220% due to a 6-fold increase in Li2S formation. To understand the growth mechanism, electrodeposition of Li2S was carried out under both galvanostatic and potentiostatic control. The observed kinetics under potentiostatic control were modeled using modified Avrami phase transformation kinetics, which showed that BPI slows the impingement of insulating Li2S islands on carbon. Conceptually, the pairing of conductive carbons with BPI can be viewed as a vascular approach to the design of current collectors for energy storage devices: here, conductive carbon "arteries" dominate long-range electron transport, while BPI "capillaries" mediate short-range transport and electron transfer between the storage materials and the carbon electrode. PMID:26691496

  5. SPINDLY, ERECTA, and its ligand STOMAGEN have a role in redox-mediated cortex proliferation in the Arabidopsis root.

    PubMed

    Cui, Hongchang; Kong, Danyu; Wei, Pengcheng; Hao, Yueling; Torii, Keiko U; Lee, Jin Suk; Li, Jie

    2014-12-01

    Reactive oxygen species (ROS) are harmful to all living organisms and therefore they must be removed to ensure normal growth and development. ROS are also signaling molecules, but so far little is known about the mechanisms of ROS perception and developmental response in plants. We here report that hydrogen peroxide induces cortex proliferation in the Arabidopsis root and that SPINDLY (SPY), an O-linked glucosamine acetyltransferase, regulates cortex proliferation by maintaining cellular redox homeostasis. We also found that mutation in the leucine-rich receptor kinase ERECTA and its putative peptide ligand STOMAGEN block the effect of hydrogen peroxide on root cortex proliferation. However, ERECTA and STOMAGEN are expressed in the vascular tissue, whereas extra cortex cells are produced from the endodermis, suggesting the involvement of intercellular signaling. SPY appears to act downstream of ERECTA, because the spy mutation still caused cortex proliferation in the erecta mutant background. We therefore have not only gained insight into the mechanism by which SPY regulates root development but also uncovered a novel pathway for ROS signaling in plants. The importance of redox-mediated cortex proliferation as a protective mechanism against oxidative stress is also discussed. PMID:25267734

  6. SPINDLY, ERECTA, and Its Ligand STOMAGEN Have a Role in Redox-Mediated Cortex Proliferation in the Arabidopsis Root

    PubMed Central

    Cui, Hongchang; Kong, Danyu; Wei, Pengcheng; Hao, Yueling; Torii, Keiko U.; Lee, Jin Suk; Li, Jie

    2014-01-01

    Reactive oxygen species (ROS) are harmful to all living organisms and therefore they must be removed to ensure normal growth and development. ROS are also signaling molecules, but so far little is known about the mechanisms of ROS perception and developmental response in plants. We here report that hydrogen peroxide induces cortex proliferation in the Arabidopsis root and that SPINDLY (SPY), an O-linked glucosamine acetyltransferase, regulates cortex proliferation by maintaining cellular redox homeostasis. We also found that mutation in the leucine-rich receptor kinase ERECTA and its putative peptide ligand STOMAGEN block the effect of hydrogen peroxide on root cortex proliferation. However, ERECTA and STOMAGEN are expressed in the vascular tissue, whereas extra cortex cells are produced from the endodermis, suggesting the involvement of intercellular signaling. SPY appears to act downstream of ERECTA, because the spy mutation still caused cortex proliferation in the erecta mutant background. We therefore have not only gained insight into the mechanism by which SPY regulates root development but also uncovered a novel pathway for ROS signaling in plants. The importance of redox-mediated cortex proliferation as a protective mechanism against oxidative stress is also discussed. PMID:25267734

  7. The effect of salinity, redox mediators and temperature on anaerobic biodegradation of petroleum hydrocarbons in microbial fuel cells.

    PubMed

    Adelaja, Oluwaseun; Keshavarz, Tajalli; Kyazze, Godfrey

    2015-01-01

    Microbial fuel cells (MFCs) need to be robust if they are to be applied in the field for bioremediation. This study investigated the effect of temperature (20-50°C), salinity (0.5-2.5% (w/v) as sodium chloride), the use of redox mediators (riboflavin and anthraquinone-2-sulphonate, AQS) and prolonged fed-batch operation (60 days) on biodegradation of a petroleum hydrocarbon mix (i.e. phenanthrene and benzene) in MFCs. The performance criteria were degradation efficiency, % COD removal and electrochemical performance. Good electrochemical and degradation performance were maintained up to a salinity of 1.5% (w/v) but deteriorated by 35-fold and 4-fold respectively as salinity was raised to 2.5%w/v. Degradation rates and maximum power density were both improved by approximately 2-fold at 40°C compared to MFC performance at 30°C but decreased sharply by 4-fold when operating temperature was raised to 50°C. The optimum reactor performance obtained at 40°C was 1.15 mW/m(2) maximum power density, 89.1% COD removal and a degradation efficiency of 97.10%; at moderately saline (1% w/v) conditions the maximum power density was 1.06 mW/m(2), 79.1% COD removal and 91.6% degradation efficiency. This work suggests the possible application of MFC technology in the effective treatment of petroleum hydrocarbons contaminated site and refinery effluents.

  8. Losartan-antioxidant hybrids: novel molecules for the prevention of hypertension-induced cardiovascular damage.

    PubMed

    García, Gonzalo; Rodríguez-Puyol, Manuel; Alajarín, Ramón; Serrano, Isabel; Sánchez-Alonso, Patricia; Griera, Mercedes; Vaquero, Juan J; Rodríguez-Puyol, Diego; Alvarez-Builla, Julio; Díez-Marqués, María L

    2009-11-26

    We report the first examples of a new series of antioxidant-sartan hybrids (AO-sartans), which were made by adding an antioxidant fragment to the hydroxymethyl side chain of losartan. Experiments performed in cultured cells demonstrate that these new hybrids retain the ability to block the angiotensin II effect with increased antioxidant ability. In hypertensive rats, these compounds show properties that suggest they may be more useful than losartan for controlling hypertension and preventing hypertension-induced cardiovascular damage.

  9. p66Shc regulates renal vascular tone in hypertension-induced nephropathy.

    PubMed

    Miller, Bradley; Palygin, Oleg; Rufanova, Victoriya A; Chong, Andrew; Lazar, Jozef; Jacob, Howard J; Mattson, David; Roman, Richard J; Williams, Jan M; Cowley, Allen W; Geurts, Aron M; Staruschenko, Alexander; Imig, John D; Sorokin, Andrey

    2016-07-01

    Renal preglomerular arterioles regulate vascular tone to ensure a large pressure gradient over short distances, a function that is extremely important for maintaining renal microcirculation. Regulation of renal microvascular tone is impaired in salt-sensitive (SS) hypertension-induced nephropathy, but the molecular mechanisms contributing to this impairment remain elusive. Here, we assessed the contribution of the SH2 adaptor protein p66Shc (encoded by Shc1) in regulating renal vascular tone and the development of renal vascular dysfunction associated with hypertension-induced nephropathy. We generated a panel of mutant rat strains in which specific modifications of Shc1 were introduced into the Dahl SS rats. In SS rats, overexpression of p66Shc was linked to increased renal damage. Conversely, deletion of p66Shc from these rats restored the myogenic responsiveness of renal preglomerular arterioles ex vivo and promoted cellular contraction in primary vascular smooth muscle cells (SMCs) that were isolated from renal vessels. In primary SMCs, p66Shc restricted the activation of transient receptor potential cation channels to attenuate cytosolic Ca2+ influx, implicating a mechanism by which overexpression of p66Shc impairs renal vascular reactivity. These results establish the adaptor protein p66Shc as a regulator of renal vascular tone and a driver of impaired renal vascular function in hypertension-induced nephropathy. PMID:27270176

  10. Efficient dye regeneration at low driving force achieved in triphenylamine dye LEG4 and TEMPO redox mediator based dye-sensitized solar cells.

    PubMed

    Yang, Wenxing; Vlachopoulos, Nick; Hao, Yan; Hagfeldt, Anders; Boschloo, Gerrit

    2015-06-28

    Minimizing the driving force required for the regeneration of oxidized dyes using redox mediators in an electrolyte is essential to further improve the open-circuit voltage and efficiency of dye-sensitized solar cells (DSSCs). Appropriate combinations of redox mediators and dye molecules should be explored to achieve this goal. Herein, we present a triphenylamine dye, LEG4, in combination with a TEMPO-based electrolyte in acetonitrile (E(0) = 0.89 V vs. NHE), reaching an efficiency of up to 5.4% under one sun illumination and 40% performance improvement compared to the previously and widely used indoline dye D149. The origin of this improvement was found to be the increased dye regeneration efficiency of LEG4 using the TEMPO redox mediator, which regenerated more than 80% of the oxidized dye with a driving force of only ∼0.2 eV. Detailed mechanistic studies further revealed that in addition to electron recombination to oxidized dyes, recombination of electrons from the conducting substrate and the mesoporous TiO2 film to the TEMPO(+) redox species in the electrolyte accounts for the reduced short circuit current, compared to the state-of-the-art cobalt tris(bipyridine) electrolyte system. The diffusion length of the TEMPO-electrolyte based DSSCs was determined to be ∼0.5 μm, which is smaller than the ∼2.8 μm found for cobalt-electrolyte based DSSCs. These results show the advantages of using LEG4 as a sensitizer, compared to previously record indoline dyes, in combination with a TEMPO-based electrolyte. The low driving force for efficient dye regeneration presented by these results shows the potential to further improve the power conversion efficiency (PCE) of DSSCs by utilizing redox couples and dyes with a minimal need of driving force for high regeneration yields.

  11. Efficient dye regeneration at low driving force achieved in triphenylamine dye LEG4 and TEMPO redox mediator based dye-sensitized solar cells.

    PubMed

    Yang, Wenxing; Vlachopoulos, Nick; Hao, Yan; Hagfeldt, Anders; Boschloo, Gerrit

    2015-06-28

    Minimizing the driving force required for the regeneration of oxidized dyes using redox mediators in an electrolyte is essential to further improve the open-circuit voltage and efficiency of dye-sensitized solar cells (DSSCs). Appropriate combinations of redox mediators and dye molecules should be explored to achieve this goal. Herein, we present a triphenylamine dye, LEG4, in combination with a TEMPO-based electrolyte in acetonitrile (E(0) = 0.89 V vs. NHE), reaching an efficiency of up to 5.4% under one sun illumination and 40% performance improvement compared to the previously and widely used indoline dye D149. The origin of this improvement was found to be the increased dye regeneration efficiency of LEG4 using the TEMPO redox mediator, which regenerated more than 80% of the oxidized dye with a driving force of only ∼0.2 eV. Detailed mechanistic studies further revealed that in addition to electron recombination to oxidized dyes, recombination of electrons from the conducting substrate and the mesoporous TiO2 film to the TEMPO(+) redox species in the electrolyte accounts for the reduced short circuit current, compared to the state-of-the-art cobalt tris(bipyridine) electrolyte system. The diffusion length of the TEMPO-electrolyte based DSSCs was determined to be ∼0.5 μm, which is smaller than the ∼2.8 μm found for cobalt-electrolyte based DSSCs. These results show the advantages of using LEG4 as a sensitizer, compared to previously record indoline dyes, in combination with a TEMPO-based electrolyte. The low driving force for efficient dye regeneration presented by these results shows the potential to further improve the power conversion efficiency (PCE) of DSSCs by utilizing redox couples and dyes with a minimal need of driving force for high regeneration yields. PMID:26016854

  12. A redox-mediator-free solar-driven Z-scheme water-splitting system consisting of modified Ta3N5 as an oxygen-evolution photocatalyst.

    PubMed

    Ma, Su Su Khine; Maeda, Kazuhiko; Hisatomi, Takashi; Tabata, Masashi; Kudo, Akihiko; Domen, Kazunari

    2013-06-01

    Tantalum nitride (Ta3N5) modified with various O2-evolution cocatalysts was employed as a photocatalyst for water oxidation under visible light (λ>420 nm) in an attempt to construct a redox-mediator-free Z-scheme water-splitting system. Ta3N5 was prepared by nitriding Ta2O5 powder under a flow of NH3 at 1023-1223 K. The activity of Ta3N5 for water oxidation from an aqueous AgNO3 solution as an electron acceptor without cocatalyst was dependent on the generation of a well-crystallized Ta3N5 phase with a low density of anionic defects. Modification of Ta3N5 with nanoparticulate metal oxides as cocatalysts for O2 evolution improved water-oxidation activity. Of the cocatalysts examined, cobalt oxide (CoO(x)) was found to be the most effective, improving the water-oxidation efficiency of Ta3N5 by six to seven times. Further modification of CoO(x)/Ta3N5 with metallic Ir as an electron sink allowed one to achieve Z-scheme water splitting under simulated sunlight through interparticle electron transfer without the need for a shuttle redox mediator in combination with Ru-loaded SrTiO3 doped with Rh as a H2-evolution photocatalyst.

  13. Anaerobic degradation of azo dye Drimaren blue HFRL in UASB reactor in the presence of yeast extract a source of carbon and redox mediator.

    PubMed

    Baêta, B E L; Aquino, S F; Silva, S Q; Rabelo, C A

    2012-04-01

    This paper presents results on anaerobic degradation of the azo dye blue HFRL in a bench scale Upflow anaerobic sludge blanket (UASB) reactor operated at ambient temperature. The results show that the addition of yeast extract (500 mg/L) increased color removal (P < 0.05) from 62 to 93% despite the low chemical oxygen demand (COD) removal (~35%) which happened due to volatile fatty acids (VFA) accumulation. There were no differences in color removal (~91%) when yeast extract (500 mg/L) was used in the presence or absence of glucose, suggesting that yeast extract acted as source of redox mediator (riboflavin) and carbon. The specific rate of dye removal increased along the operational phases and depended on the presence of yeast extract, suggesting progressive biomass acclimatization. Analysis of bacterial diversity by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) method showed there was biomass selection along the bioreactor operation and no evidence of azo dye degrading bacteria predominance. This strengthens the hypothesis that color removal happens extracellularly by the reduction of azo bond by reduced redox mediators, such as riboflavin, which is present in high amount in the yeast extract.

  14. Glucose/O2 biofuel cell based on enzymes, redox mediators, and multiple-walled carbon nanotubes deposited by AC-electrophoresis then stabilized by electropolymerized polypyrrole.

    PubMed

    Ammam, Malika; Fransaer, Jan

    2012-07-01

    In this study, we developed an automated strategy to manufacture an enzyme BFC powered by glucose/O(2). The bioanode consists of GOx enzyme and PQQ redox mediator adsorbed over night on MWCNTs then deposited by means of AC-electrophoresis at 30 Hz and 160 V(p-p) and, finally stabilized by electropolymerized polypyrrole. The biocathode is constructed from LAc enzyme and ABTS redox mediator adsorbed over night on MWCNTs, then electrophoretically deposited under AC-electric field at 30 Hz and 160 V(p-p) and, finally stabilized by electrodeposited polypyrrole. The BFC was studied under air in phosphate buffer solution pH 7.4 containing 10 mM glucose and in human serum with 5 mM glucose addition at the physiological temperature of 37°C. Under these conditions, the maximum power density reaches 1.1 µW · mm(-2) at a cell voltage of 0.167 V in buffer solution and 0.69 µW · mm(-2) at cell voltage of 0.151 V in human serum. Such automated BFCs have a great potential to be optimized, miniaturized to micro and nanoscale devices suitable for in vivo studies.

  15. p66Shc regulates renal vascular tone in hypertension-induced nephropathy

    PubMed Central

    Miller, Bradley; Palygin, Oleg; Rufanova, Victoriya A.; Lazar, Jozef; Jacob, Howard J.; Mattson, David; Roman, Richard J.; Williams, Jan M.; Cowley, Allen W.; Geurts, Aron M.; Imig, John D.

    2016-01-01

    Renal preglomerular arterioles regulate vascular tone to ensure a large pressure gradient over short distances, a function that is extremely important for maintaining renal microcirculation. Regulation of renal microvascular tone is impaired in salt-sensitive (SS) hypertension–induced nephropathy, but the molecular mechanisms contributing to this impairment remain elusive. Here, we assessed the contribution of the SH2 adaptor protein p66Shc (encoded by Shc1) in regulating renal vascular tone and the development of renal vascular dysfunction associated with hypertension-induced nephropathy. We generated a panel of mutant rat strains in which specific modifications of Shc1 were introduced into the Dahl SS rats. In SS rats, overexpression of p66Shc was linked to increased renal damage. Conversely, deletion of p66Shc from these rats restored the myogenic responsiveness of renal preglomerular arterioles ex vivo and promoted cellular contraction in primary vascular smooth muscle cells (SMCs) that were isolated from renal vessels. In primary SMCs, p66Shc restricted the activation of transient receptor potential cation channels to attenuate cytosolic Ca2+ influx, implicating a mechanism by which overexpression of p66Shc impairs renal vascular reactivity. These results establish the adaptor protein p66Shc as a regulator of renal vascular tone and a driver of impaired renal vascular function in hypertension-induced nephropathy. PMID:27270176

  16. Effect of metal ions and redox mediators on decolorization of synthetic dyes by crude laccase from a novel white rot fungus Peniophora sp. (NFCCI-2131).

    PubMed

    Shankar, Shiv; Shikha; Nill, Shikha

    2015-01-01

    The effect of different metal ions and two redox mediators on laccase activity and laccase-catalyzed decolorization of five synthetic dyes was investigated in vitro using crude laccase from a novel white rot fungus Peniophora sp. (NFCCI-2131). The fungus effectively decolorized crystal violet and brilliant green on malt extract agar medium. Laccase activity was enhanced by metal ions such as Cd(2+), Mn(2+), Ni(2+), Co(2+), Na(+) Ca(2+), and Cu(2+). Among the different dyes tested, highest decolorization of crystal violet (96.30 %) was obtained in the presence of 1 mM ABTS followed by 86.01 % by HBT. The results conspicuously indicated that laccase from Peniophora sp. has the potential for color removal from textile dye effluent even in the presence of toxic metal ions.

  17. Biochemical characterization of laccase from hairy root culture of Brassica juncea L. and role of redox mediators to enhance its potential for the decolorization of textile dyes.

    PubMed

    Telke, Amar A; Kagalkar, Anuradha N; Jagtap, Umesh B; Desai, Neetin S; Bapat, Vishwas A; Govindwar, Sanjay P

    2011-12-01

    In vitro transgenic hairy root cultures provide a rapid system for physiological, biochemical studies and screening of plants for their phytoremediation potential. The hairy root cultures of Brassica juncea L. showed 92% decolorization of Methyl orange within 4 days. Out of the different redox mediators that were used to achieve enhanced decolorization, 2, 2'-Azinobis, 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) was found to be the most efficient. Laccase activity of 4.5 U mg(-1) of protein was observed in hairy root cultures of Brassica juncea L., after the decolorization of Methyl orange. Intracellular laccase produced by B. juncea root cultures grown in MS basal medium was purified up to 2.0 fold with 6.62 U mg(-1) specific activity using anion-exchange chromatography. Molecular weight of the purified laccase was estimated to be 148 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified enzyme efficiently oxidized ABTS which was also required for oxidation of the other tested substrates. The pH and temperature optimum for laccase activity were 4.0 and 40°C, respectively. The purified enzyme was stable up to 50°C and was stable in the pH range of 4.0-6.0. Laccase activity was strongly inhibited by sodium azide, EDTA, dithiothreitol and L: -cysteine. The purified enzyme decolorized various textile dyes in the presence of ABTS as an efficient redox mediator. These findings contribute to a better understanding of the enzymatic process involved in phytoremediation of textile dyes by using hairy roots.

  18. Evaluation of docosahexaenoic acid in a dog model of hypertension induced left ventricular hypertrophy.

    PubMed

    Stanley, William C; Cox, James W; Asemu, Girma; O'Connell, Kelly A; Dabkowski, Erinne R; Xu, Wenhong; Ribeiro, Rogerio F; Shekar, Kadambari C; Hoag, Stephen W; Rastogi, Sharad; Sabbah, Hani N; Daneault, Caroline; des Rosiers, Christine

    2013-12-01

    Marine n-3 polyunsaturated fatty acids alter cardiac phospholipids and prevent cardiac pathology in rodents subjected to pressure overload. This approach has not been evaluated in humans or large animals with hypertension-induced pathological hypertrophy. We evaluated docosahexaenoic acid (DHA) in old female dogs with hypertension caused by 16 weeks of aldosterone infusion. Aldosterone-induced hypertension resulted in concentric left ventricular (LV) hypertrophy and impaired diastolic function in placebo-treated dogs. DHA supplementation increased DHA and depleted arachidonic acid in cardiac phospholipids, but did not improve LV parameters compared to placebo. Surprisingly, DHA significantly increased serum aldosterone concentration and blood pressure compared to placebo. Cardiac mitochondrial yield was decreased in placebo-treated hypertensive dogs compared to normal animals, which was prevented by DHA. Extensive analysis of mitochondrial function found no differences between DHA and placebo groups. In conclusion, DHA did not favorably impact mitochondrial or LV function in aldosterone hypertensive dogs.

  19. Increased Klk9 Urinary Excretion Is Associated to Hypertension-Induced Cardiovascular Damage and Renal Alterations

    PubMed Central

    Blázquez-Medela, Ana M.; García-Sánchez, Omar; Quirós, Yaremi; Blanco-Gozalo, Victor; Prieto-García, Laura; Sancho-Martínez, Sandra M.; Romero, Miguel; Duarte, Juan M.; López-Hernández, Francisco J.; López-Novoa, José M.; Martínez-Salgado, Carlos

    2015-01-01

    Abstract Early detection of hypertensive end-organ damage and secondary diseases are key determinants of cardiovascular prognosis in patients suffering from arterial hypertension. Presently, there are no biomarkers for the detection of hypertensive target organ damage, most outstandingly including blood vessels, the heart, and the kidneys. We aimed to validate the usefulness of the urinary excretion of the serine protease kallikrein-related peptidase 9 (KLK9) as a biomarker of hypertension-induced target organ damage. Urinary, plasma, and renal tissue levels of KLK9 were measured by the Western blot in different rat models of hypertension, including angiotensin-II infusion, DOCA-salt, L-NAME administration, and spontaneous hypertension. Urinary levels were associated to cardiovascular and renal injury, assessed by histopathology. The origin of urinary KLK9 was investigated through in situ renal perfusion experiments. The urinary excretion of KLK9 is increased in different experimental models of hypertension in rats. The ACE inhibitor trandolapril significantly reduced arterial pressure and the urinary level of KLK9. Hypertension did not increase kidney, heart, liver, lung, or plasma KLK9 levels. Hypertension-induced increased urinary excretion of KLK9 results from specific alterations in its tubular reabsorption, even in the absence of overt nephropathy. KLK9 urinary excretion strongly correlates with cardiac hypertrophy and aortic wall thickening. KLK9 appears in the urine in the presence of hypertension as a result of subtle renal handling alterations. Urinary KLK9 might be potentially used as an indicator of hypertensive cardiac and vascular damage. PMID:26469898

  20. Effective killing of Gleevec-resistant CML cells with T315I mutation by a natural compound PEITC through redox-mediated mechanism

    PubMed Central

    Zhang, H; Trachootham, D; Lu, W; Carew, J; Giles, FJ; Keating, MJ; Arlinghaus, RB; Huang, P

    2008-01-01

    Mutation of Bcr-Abl is an important mechanism by which chronic myelogenous leukemia (CML) cells become resistant to Gleevec. The T315I mutation is clinically significant since CML cells harboring this mutation are insensitive to Gleevec and other Bcr-Abl-targeted drugs. Identification of new agents capable of effectively killing CML cells with T315I mutation would have important therapeutic implications in Gleevec-resistant CML. Here, we showed that β-phenylethyl isothiocyanate (PEITC), a natural compound found in vegetables, is effective in killing CML cells expressing T315I BCR-ABL. Treatment of leukemia cell lines harboring wild-type or mutant Bcr-Abl with 10 μm PEITC resulted in an elevated ROS stress and a redox-mediated degradation of the BCR-ABL protein, leading to massive death of the leukemia cells. Antioxidant NAC attenuated the PEITC-induced oxidative stress in CML cells and prevented the degradation of BCR-ABL, caspase-3 activation and cell death. We further showed that the ROS-induced degradation of BCR-ABL was mediated partially by caspase-3 and the proteasome pathway. The ability of PEITC to effectively kill T315I-positive CML cells was further confirmed using primary leukemia cells isolated from CML patients. Our results suggest that PEITC is a promising compound capable of killing Gleevec-resistant CML cells through a ROS-mediated mechanism and warrants further investigations. PMID:18385754

  1. Genetic susceptibility to hypertension-induced renal damage in the rat. Evidence based on kidney-specific genome transfer.

    PubMed Central

    Churchill, P C; Churchill, M C; Bidani, A K; Griffin, K A; Picken, M; Pravenec, M; Kren, V; St Lezin, E; Wang, J M; Wang, N; Kurtz, T W

    1997-01-01

    To test the hypothesis that genetic factors can determine susceptibility to hypertension-induced renal damage, we derived an experimental animal model in which two genetically different yet histocompatible kidneys are chronically and simultaneously exposed to the same blood pressure profile and metabolic environment within the same host. Kidneys from normotensive Brown Norway rats were transplanted into unilaterally nephrectomized spontaneously hypertensive rats (SHR-RT1.N strain) that harbor the major histocompatibility complex of the Brown Norway strain. 25 d after the induction of severe hypertension with deoxycorticosterone acetate and salt, proteinuria, impaired glomerular filtration rate, and extensive vascular and glomerular injury were observed in the Brown Norway donor kidneys, but not in the SHR-RT1.N kidneys. Control experiments demonstrated that the strain differences in kidney damage could not be attributed to effects of transplantation-induced renal injury, immunologic rejection phenomena, or preexisting strain differences in blood pressure. These studies (a) demonstrate that the kidney of the normotensive Brown Norway rat is inherently much more susceptible to hypertension-induced damage than is the kidney of the spontaneously hypertensive rat, and (b) establish the feasibility of using organ-specific genome transplants to map genes expressed in the kidney that determine susceptibility to hypertension-induced renal injury in the rat. PMID:9294102

  2. Genetic susceptibility to hypertension-induced renal damage in the rat. Evidence based on kidney-specific genome transfer.

    PubMed

    Churchill, P C; Churchill, M C; Bidani, A K; Griffin, K A; Picken, M; Pravenec, M; Kren, V; St Lezin, E; Wang, J M; Wang, N; Kurtz, T W

    1997-09-15

    To test the hypothesis that genetic factors can determine susceptibility to hypertension-induced renal damage, we derived an experimental animal model in which two genetically different yet histocompatible kidneys are chronically and simultaneously exposed to the same blood pressure profile and metabolic environment within the same host. Kidneys from normotensive Brown Norway rats were transplanted into unilaterally nephrectomized spontaneously hypertensive rats (SHR-RT1.N strain) that harbor the major histocompatibility complex of the Brown Norway strain. 25 d after the induction of severe hypertension with deoxycorticosterone acetate and salt, proteinuria, impaired glomerular filtration rate, and extensive vascular and glomerular injury were observed in the Brown Norway donor kidneys, but not in the SHR-RT1.N kidneys. Control experiments demonstrated that the strain differences in kidney damage could not be attributed to effects of transplantation-induced renal injury, immunologic rejection phenomena, or preexisting strain differences in blood pressure. These studies (a) demonstrate that the kidney of the normotensive Brown Norway rat is inherently much more susceptible to hypertension-induced damage than is the kidney of the spontaneously hypertensive rat, and (b) establish the feasibility of using organ-specific genome transplants to map genes expressed in the kidney that determine susceptibility to hypertension-induced renal injury in the rat.

  3. The complex regulation of tanshinone IIA in rats with hypertension-induced left ventricular hypertrophy.

    PubMed

    Pang, Hui; Han, Bing; Yu, Tao; Peng, Zhen

    2014-01-01

    Tanshinone IIA has definite protective effects on various cardiovascular diseases. However, in hypertension-induced left ventricular hypertrophy (H-LVH), the signaling pathways of tanshinone IIA in inhibition of remodeling and cardiac dysfunction remain unclear. Two-kidney, one-clip induced hypertensive rats (n = 32) were randomized to receive tanshinone IIA (5, 10, 15 mg/kg per day) or 5% glucose injection (GS). Sham-operated rats (n = 8) received 5%GS as control. Cardiac function and dimensions were assessed by using an echocardiography system. Histological determination of the fibrosis and apoptosis was performed using hematoxylin eosin, Masson's trichrome and TUNEL staining. Matrix metalloproteinase 2 (MMP2) and tissue inhibitor of matrix metalloproteinases type 2 (TIMP2) protein expressions in rat myocardial tissues were detected by immunohistochemistry. Rat cardiomyocytes were isolated by a Langendorff perfusion method. After 48 h culture, the supernatant and cardiomyocytes were collected to determine the potential related proteins impact on cardiac fibrosis and apoptosis. Compared with the sham rats, the heart tissues of H-LVH (5%GS) group suffered severely from the oxidative damage, apoptosis of cardiomyocytes and extracellular matrix (ECM) deposition. In the H-LVH group, tanshinone IIA treated decreased malondialdehyde (MDA) content and increased superoxide dismutase (SOD) activity. Tanshinone IIA inhibited cardiomyocytes apoptosis as confirmed by the reduction of TUNEL positive cardiomyocytes and the down-regulation of Caspase-3 activity and Bax/Bcl-2 ratio. Meanwhile, plasma apelin level increased with down-regulation of APJ receptor. Tanshinone IIA suppressed cardiac fibrosis through regulating the paracrine factors released by cardiomyocytes and the TGF-β/Smads signaling pathway activity. In conclusion, our in vivo study showed that tanshinone IIA could improve heart function by enhancing myocardial contractility, inhibiting ECM deposition

  4. Fractal Dimension in Quantifying Experimental-Pulmonary-Hypertension-Induced Cardiac Dysfunction in Rats

    PubMed Central

    Pacagnelli, Francis Lopes; Sabela, Ana Karênina Dias de Almeida; Mariano, Thaoan Bruno; Ozaki, Guilherme Akio Tamura; Castoldi, Robson Chacon; do Carmo, Edna Maria; Carvalho, Robson Francisco; Tomasi, Loreta Casquel; Okoshi, Katashi; Vanderlei, Luiz Carlos Marques

    2016-01-01

    Background Right-sided heart failure has high morbidity and mortality, and may be caused by pulmonary arterial hypertension. Fractal dimension is a differentiated and innovative method used in histological evaluations that allows the characterization of irregular and complex structures and the quantification of structural tissue changes. Objective To assess the use of fractal dimension in cardiomyocytes of rats with monocrotaline-induced pulmonary arterial hypertension, in addition to providing histological and functional analysis. Methods Male Wistar rats were divided into 2 groups: control (C; n = 8) and monocrotaline-induced pulmonary arterial hypertension (M; n = 8). Five weeks after pulmonary arterial hypertension induction with monocrotaline, echocardiography was performed and the animals were euthanized. The heart was dissected, the ventricles weighed to assess anatomical parameters, and histological slides were prepared and stained with hematoxylin/eosin for fractal dimension analysis, performed using box-counting method. Data normality was tested (Shapiro-Wilk test), and the groups were compared with non-paired Student t test or Mann Whitney test (p < 0.05). Results Higher fractal dimension values were observed in group M as compared to group C (1.39 ± 0.05 vs. 1.37 ± 0.04; p < 0.05). Echocardiography showed lower pulmonary artery flow velocity, pulmonary acceleration time and ejection time values in group M, suggesting function worsening in those animals. Conclusion The changes observed confirm pulmonary-arterial-hypertension-induced cardiac dysfunction, and point to fractal dimension as an effective method to evaluate cardiac morphological changes induced by ventricular dysfunction. PMID:27223643

  5. Genetic isolation of a chromosome 1 region affecting susceptibility to hypertension-induced renal damage in the spontaneously hypertensive rat.

    PubMed

    St Lezin, E; Griffin, K A; Picken, M; Churchill, M C; Churchill, P C; Kurtz, T W; Liu, W; Wang, N; Kren, V; Zidek, V; Pravenec, M; Bidani, A K

    1999-08-01

    Linkage studies in the fawn-hooded hypertensive rat have suggested that genes influencing susceptibility to hypertension-associated renal failure may exist on rat chromosome 1q. To investigate this possibility in a widely used model of hypertension, the spontaneously hypertensive rat (SHR), we compared susceptibility to hypertension-induced renal damage between an SHR progenitor strain and an SHR congenic strain that is genetically identical except for a defined region of chromosome 1q. Backcross breeding with selection for the markers D1Mit3 and Igf2 on chromosome 1 was used to create the congenic strain (designated SHR.BN-D1Mit3/Igf2) that carries a 22 cM segment of chromosome 1 transferred from the normotensive Brown Norway rat onto the SHR background. Systolic blood pressure (by radiotelemetry) and urine protein excretion were measured in the SHR progenitor and congenic strains before and after the induction of accelerated hypertension by administration of DOCA-salt. At the same level of DOCA-salt hypertension, the SHR.BN-D1Mit3/Igf2 congenic strain showed significantly greater proteinuria and histologically assessed renal vascular and glomerular injury than the SHR progenitor strain. These findings demonstrate that a gene or genes that influence susceptibility to hypertension-induced renal damage have been trapped in the differential chromosome segment of the SHR.BN-D1Mit3/Igf2 congenic strain. This congenic strain represents an important new model for the fine mapping of gene(s) on chromosome 1 that affect susceptibility to hypertension-induced renal injury in the rat.

  6. Endothelial Lessons.

    PubMed

    Vanhoutte, Paul M

    2016-01-01

    This essay focuses on nine important lessons learned during more than thirty years of endothelial research. They include: the danger of hiding behind a word, the confusion generated by abbreviations, the need to define the physiological role of the response studied, the local role of endothelium- dependent responses, the strength of pharmacological analyses, endothelial dysfunction as consequence and cause of disease, the importance of rigorous protocols, the primacy of in vivo studies and the importance of serendipity. PMID:26638800

  7. The Effects of Hydroalchoholic Extract of Teucrium polium L. on Hypertension Induced by Angiotensin II in Rats

    PubMed Central

    Mahmoudabady, Maryam; Shafei, Mohammad Naser; Niazmand, Saeed; Khodaee, Esmaeel

    2014-01-01

    Background: Antispasmodic and vasorelaxant effects of Teucrium polium L. (TP) were mentioned in former studies, so we attempted to evaluate the eventual preventive effect of TP in an acute experimental model of hypertension induced by angiotensin II (Ang II). Methods: Forty-eight male Wistar rats were divided randomly into six groups (n = 8); control Group (C), which received only saline, group Ang II; which received Ang II (300 ng/min, IV), group losartan (Los); which received Los (10 mg/kg, IV) before Ang II injection, three groups of TP 100, TP 200, and TP 400; which received different doses of TP extract (100, 200 and 400 mg/kg, IP, respectively) before Ang II application. After cannulation of the femoral artery, mean arterial blood pressure (MAP) and heart rate (HR) was continuously measured and recorded during the experiments. Comparisons were performed using t-test with SPSS software, version 16 (SPSS, Chicago, IL). Results: MAP and HR in Ang group were significantly higher than the control group (P < 0.001), MAP in group Los significantly was lower than Ang group (P < 0.001) and pretreatment with three doses of TP extract also inhibited increasing of MAP after Ang II injection (P < 0.001). Los also inhibited the increase of HR due to Ang II (P < 0.001), but none of three doses of TP extract had a protective effect on tachycardia induced by Ang II. Conclusions: It seems TP extract could be effective in preventing of high blood pressure induced by Ang II pathway activation but could not have remarkable efficacy for improving the created tachycardia. PMID:25400883

  8. Oxidative stress exaggerates skeletal muscle contraction-evoked reflex sympathoexcitation in rats with hypertension induced by angiotensin II.

    PubMed

    Koba, Satoshi; Watanabe, Ryosuke; Kano, Naoko; Watanabe, Tatsuo

    2013-01-01

    Muscle contraction stimulates thin fiber muscle afferents and evokes reflex sympathoexcitation. In hypertension, this reflex is exaggerated. ANG II, which is elevated in hypertension, has been reported to trigger the production of superoxide and other reactive oxygen species. In the present study, we tested the hypothesis that increased ANG II in hypertension exaggerates skeletal muscle contraction-evoked reflex sympathoexcitation by inducing oxidative stress in the muscle. In rats, subcutaneous infusion of ANG II at 450 ng·kg(-1)·min(-1) for 14 days significantly (P < 0.05) elevated blood pressure compared with sham-operated (sham) rats. Electrically induced 30-s hindlimb muscle contraction in decerebrate rats with hypertension evoked larger renal sympathoexcitatory and pressor responses [+1,173 ± 212 arbitrary units (AU) and +35 ± 5 mmHg, n = 10] compared with sham normotensive rats (+419 ± 103 AU and +13 ± 2 mmHg, n = 11). Tempol, a SOD mimetic, injected intra-arterially into the hindlimb circulation significantly reduced responses in hypertensive rats, whereas this compound had no effect on responses in sham rats. Tiron, another SOD mimetic, also significantly reduced reflex renal sympathetic and pressor responses in a subset of hypertensive rats (n = 10). Generation of muscle superoxide, as evaluated by dihydroethidium staining, was increased in hypertensive rats. RT-PCR and immunoblot experiments showed that mRNA and protein for gp91(phox), a NADPH oxidase subunit, in skeletal muscle tissue were upregulated in hypertensive rats. Taken together, hese results suggest that increased ANG II in hypertension induces oxidative stress in skeletal muscle, thereby exaggerating the muscle reflex.

  9. Borane-protected phosphines are redox-active radioprotective agents for endothelial cells.

    PubMed

    Crowe, Megan E; Lieven, Christopher J; Thompson, Alex F; Sheibani, Nader; Levin, Leonard A

    2015-12-01

    Exposure to radiation can damage endothelial cells in the irradiated area via the production of reactive oxygen species. We synthesized phosphine-borane complexes that reduce disulfide bonds and had previously been shown to interfere with redox-mediated signaling of cell death. We hypothesized that this class of drugs could interfere with the downstream effects of oxidative stress after irradiation and rescue endothelial cells from radiation damage. Cultured bovine aortic endothelial cells were plated for clonogenic assay prior to exposure to varying doses of irradiation from a (137)Cs irradiator and treated with various concentrations of bis(3-propionic acid methyl ester)phenylphosphine borane complex (PB1) at different time points. The clone-forming ability of the irradiated cells was assessed seven days after irradiation. We compared the radioprotective effects of PB1 with the aminothiol radioprotectant WR1065 and known superoxide scavengers. PB1 significantly protected bovine aortic endothelial cells from radiation damage, particularly when treated both before and after radiation. The radioprotection with 1 µM PB1 corresponded to a dose-reduction factor of 1.24. Radioprotection by PB1 was comparable to the aminothiol WR1065, but was significantly less toxic and required much lower concentrations of drug (1 µM vs. 4 mM, respectively). Superoxide scavengers were not radioprotective in this paradigm, indicating the mechanisms for both loss of clonogenicity and PB1 radioprotection are independent of superoxide signaling. These data demonstrate that PB1 is an effective redox-active radioprotectant for endothelial cells in vitro, and is radioprotective at a concentration approximately 4 orders of magnitude lower than the aminothiol WR1065 with less toxicity. PMID:26188467

  10. Borane-protected phosphines are redox-active radioprotective agents for endothelial cells

    PubMed Central

    Crowe, Megan E.; Lieven, Christopher J.; Thompson, Alex F.; Sheibani, Nader; Levin, Leonard A.

    2015-01-01

    Exposure to radiation can damage endothelial cells in the irradiated area via the production of reactive oxygen species. We synthesized phosphine–borane complexes that reduce disulfide bonds and had previously been shown to interfere with redox-mediated signaling of cell death. We hypothesized that this class of drugs could interfere with the downstream effects of oxidative stress after irradiation and rescue endothelial cells from radiation damage. Cultured bovine aortic endothelial cells were plated for clonogenic assay prior to exposure to varying doses of irradiation from a 137Cs irradiator and treated with various concentrations of bis(3-propionic acid methyl ester)phenylphosphine borane complex (PB1) at different time points. The clone-forming ability of the irradiated cells was assessed seven days after irradiation. We compared the radioprotective effects of PB1 with the aminothiol radioprotectant WR1065 and known superoxide scavengers. PB1 significantly protected bovine aortic endothelial cells from radiation damage, particularly when treated both before and after radiation. The radioprotection with 1 µM PB1 corresponded to a dose-reduction factor of 1.24. Radioprotection by PB1 was comparable to the aminothiol WR1065, but was significantly less toxic and required much lower concentrations of drug (1 µM vs. 4 mM, respectively). Superoxide scavengers were not radioprotective in this paradigm, indicating the mechanisms for both loss of clonogenicity and PB1 radioprotection are independent of superoxide signaling. These data demonstrate that PB1 is an effective redox-active radioprotectant for endothelial cells in vitro, and is radioprotective at a concentration approximately 4 orders of magnitude lower than the aminothiol WR1065 with less toxicity. PMID:26188467

  11. Micro-biofuel cell powered by glucose/O2 based on electro-deposition of enzyme, conducting polymer and redox mediators: preparation, characterization and performance in human serum.

    PubMed

    Ammam, Malika; Fransaer, Jan

    2010-02-15

    In this study we report a new simple process to manufacture a biofuel cell consisting of a glucose oxidase (GOx) based anode and a laccase (LAc) based cathode. The process is based on the electro-deposition of the enzymes, conducting polymer and redox mediators from ultrapure water at a potential of 4V vs. AgCl/Ag. Contrary to the conventional electro-deposition from high ionic strength (buffer solution) at low applied potential (1V vs. AgCl/Ag) where only thin films could be deposited, leading to BFC with moderate power, the electro-deposition from ultrapure water at 4V allows the growth of thick films leading to BFC with high power output. It was observed that the combination of polypyrrole (PPy), with ferrocenium hexafluorophosphate (FHFP) and pyrroloquinoline quinone (PQQ) to be appropriate for the electron transfer at the GOx bioanode, while the combination of polypyrrole with bis-(bipyridine)-(5-amino-phenanthroline) ruthenium bis (hexafluorophosphate)(RuPy) and 4,4-sulfonyldiphenol (SDP) to be effective for the electron transfer at the LAc biocathode. The working biofuel cell was studied at 37 degrees C in phosphate buffer solution at pH 7.4 containing 10 mM glucose and in human serum. Under these conditions, the maximum power density reached 3.1 microW mm(-2) at a cell voltage of 0.28 V in buffer solution and 1.6 microW mm(-2) at a cell voltage of 0.21 V in human serum. This study offers a new route to the development of enzymatic BFCs with high performance and provides information on enzymatic BFCs as in vivo power sources.

  12. Micro-biofuel cell powered by glucose/O2 based on electro-deposition of enzyme, conducting polymer and redox mediators: preparation, characterization and performance in human serum.

    PubMed

    Ammam, Malika; Fransaer, Jan

    2010-02-15

    In this study we report a new simple process to manufacture a biofuel cell consisting of a glucose oxidase (GOx) based anode and a laccase (LAc) based cathode. The process is based on the electro-deposition of the enzymes, conducting polymer and redox mediators from ultrapure water at a potential of 4V vs. AgCl/Ag. Contrary to the conventional electro-deposition from high ionic strength (buffer solution) at low applied potential (1V vs. AgCl/Ag) where only thin films could be deposited, leading to BFC with moderate power, the electro-deposition from ultrapure water at 4V allows the growth of thick films leading to BFC with high power output. It was observed that the combination of polypyrrole (PPy), with ferrocenium hexafluorophosphate (FHFP) and pyrroloquinoline quinone (PQQ) to be appropriate for the electron transfer at the GOx bioanode, while the combination of polypyrrole with bis-(bipyridine)-(5-amino-phenanthroline) ruthenium bis (hexafluorophosphate)(RuPy) and 4,4-sulfonyldiphenol (SDP) to be effective for the electron transfer at the LAc biocathode. The working biofuel cell was studied at 37 degrees C in phosphate buffer solution at pH 7.4 containing 10 mM glucose and in human serum. Under these conditions, the maximum power density reached 3.1 microW mm(-2) at a cell voltage of 0.28 V in buffer solution and 1.6 microW mm(-2) at a cell voltage of 0.21 V in human serum. This study offers a new route to the development of enzymatic BFCs with high performance and provides information on enzymatic BFCs as in vivo power sources. PMID:20005695

  13. Imperatorin derivative OW1 inhibits the upregulation of TGF-β and MMP-2 in renovascular hypertension-induced cardiac remodeling

    PubMed Central

    ZHOU, NAN; ZHU, YANING; ZHANG, PENG; ZHANG, YU; ZHOU, MINGYAO; WANG, TAO; HE, LANGCHONG

    2016-01-01

    Chronic hypertension induces vascular and cardiac remodeling. OW1 is a novel imperatorin derivative that was previously reported to inhibit vascular remodeling and improve kidney function affected by hypertension. In the present study, the effect of OW1 on the cardiac remodeling induced by hypertension was investigated. OW1 inhibited vascular smooth muscle cell (VSMC) proliferation and the phenotypic modulation of VSMCs induced by angiotensin II (Ang II). The OW1-induced vasodilatation of rat cardiac arteries was evaluated in vitro. Renovascular hypertensive rats were developed using the two-kidney one-clip method and treated with OW1 (40 or 80 mg/kg/day) or nifedipine (30 mg/kg per day) for 5 weeks. OW1 markedly reduced the systolic and diastolic blood pressure compared with that in the hypertension group or the respective baseline value during the first week. OW1 also reduced cardiac weight, and the concentrations of Ang II, aldosterone and transforming growth factor-β1 (TGF-β1). Histological examination demonstrated that OW1 exerted an inhibitory effect on vascular and cardiac remodeling. These inhibitory effects were associated with decreased cardiac levels of Ang II, matrix metalloproteinase-2 and TGF-β1 in the hypertensive rats. In summary, OW1 exhibited a clear antihypertensive effect. More importantly, it inhibited vascular and cardiovascular remodeling, which may reduce the risk of hypertension-induced cardiovascular diseases. These results have potential implications in the development of new antihypertensive drugs. PMID:27168797

  14. [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.

  15. Facile Synthesis of Novel Redox-Mediator-free Direct Z-Scheme CaIn2S4 Marigold-Flower-like/TiO2 Photocatalysts with Superior Photocatalytic Efficiency.

    PubMed

    Jo, Wan-Kuen; Sivakumar Natarajan, Thillai

    2015-08-12

    Novel redox-mediator-free direct Z-scheme CaIn2S4 marigold-flower-like/TiO2 (CIS/TNP) photocatalysts with different CaIn2S4 weight percentages were synthesized using a facile wet-impregnation method. Uniform hierarchical marigold-flower-like CaIn2S4 (CIS) microspheres were synthesized using a hydrothermal method. Field-emission scanning electron microscopy and transmission electron microscopy analyses suggested that the formation and aggregation of nanoparticles, followed by the growth of petals or sheets and their subsequent self-assembly, led to the formation of the uniform hierarchical marigold-flower-like CIS structures. The photocatalytic degradation efficiency of the direct Z-scheme CIS/TNP photocatalysts was evaluated through the degradation of the pharmaceutical compounds isoniazid (ISN) and metronidazole (MTZ). The direct Z-scheme CaIn2S4 marigold-flower-like/TiO2 (1%-CIS/TNP) photocatalyst showed enhanced performance in the ISN (71.9%) and MTZ (86.5%) photocatalytic degradations as compared to composites with different CaIn2S4 contents or the individual TiO2 and CaIn2S4. A possible enhancement mechanism based on the Z-scheme formed between the CIS and TNP for the improved photocatalytic efficiency was also proposed. The recombination rate of the photoinduced charge carriers was significantly suppressed for the direct Z-scheme CIS/TNP photocatalyst, which was confirmed by photoluminescence analysis. Radical-trapping studies revealed that photogenerated holes (h+), •OH, and O2•- are the primary active species, and suggested that the enhanced photocatalytic efficiency of the 1%-CIS/TNP follows the Z-scheme mechanism for transferring the charge carriers. It was further confirmed by hydroxyl (•OH) radical determination via fluorescence techniques revealed that higher concentration of •OH radical were formed over 1%-CIS/TNP than over bare CIS and TNP. The separation of the charge carriers was further confirmed using photocurrent and electron spin

  16. Fabrication of hierarchically structured novel redox-mediator-free ZnIn2S4 marigold flower/Bi2WO6 flower-like direct Z-scheme nanocomposite photocatalysts with superior visible light photocatalytic efficiency.

    PubMed

    Jo, Wan-Kuen; Lee, Joon Yeob; Natarajan, Thillai Sivakumar

    2016-01-14

    Novel, hierarchically nanostructured, redox-mediator-free, direct Z-scheme nanocomposite photocatalysts were synthesized via a facile hydrothermal method followed by wet-impregnation. The photocatalysts had a ZnIn2S4 marigold flower/Bi2WO6 flower-like (ZIS/BW) composition, which led to superior visible-light photocatalytic efficiency with excellent stability and reusability. The hierarchical marigold flower and flower-like morphologies of ZIS and BW were confirmed by FE-SEM and TEM analyses and further revealed that formation of the hierarchical marigold flower-like ZIS structure followed the formation of nanoparticles, growth of the ZIS petals, and self-assembly of these species. Powder X-ray diffraction and UV-visible diffuse reflectance spectroscopy analyses as well as the enhancement in the surface area and pore volume of the composite provide evidence of strong coupling between hierarchical BW and the ZIS nanostructures. The efficiency of the hierarchical direct Z-scheme photocatalysts for photocatalytic decomposition of metronidazole (MTZ) under visible-light irradiation was evaluated. The hierarchically nanostructured ZIS/BW nanocomposites with 50% loading of ZIS exhibited superior visible-light photocatalytic decomposition efficiency (PDE) compared to the composites with other percentages of ZIS and pristine BW. A probable mechanism for the enhanced photocatalytic efficiency of the ZIS/BW composite in MTZ degradation under visible irradiation was proposed. Radical quenching studies demonstrated that h(+), ˙OH, and O2˙(-) are the primary reactive radicals involved, which confirms that the Z-scheme mechanism of transfer of charge carriers accounts for the higher photocatalytic activity. Kinetic analysis revealed that MTZ degradation follows pseudo-first-order kinetics and the reusability of the composite catalyst for up to four cycles confirms the excellent stability of the hierarchical structure. It is concluded that the hierarchical structure of the ZIS

  17. [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.

  18. Effect of rosuvastatin on hyperuricemic rats and the protective effect on endothelial dysfunction.

    PubMed

    Xilifu, Dilidaer; Abudula, Abulizi; Rehemu, Nijiati; Zhao, Long; Zhou, Xinrong; Zhang, Xiangyang

    2014-12-01

    Endothelial dysfunction plays a key role in the development of cardiovascular diseases, renal injuries and hypertension induced by hyperuricemia. Therapies targeting uric acid (UA) may be beneficial in cardiovascular diseases. In the present study, the effect of rosuvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, was investigated to determine whether rosuvastatin improves endothelial dysfunction via the endothelial nitric oxide (NO) pathway and delays the pathogenesis of endothelial dysfunction in hyperuricemic rats. A total of 72 Sprague-Dawley rats (age, 8 weeks) were randomly divided into six groups (12 rats per group), including the control, model, 2.5 mg/kg/day rosuvastatin, 5 mg/kg/day rosuvastatin, 10 mg/kg/day rosuvastatin and 53.57 mg/kg/day allopurinol groups. The model, rosuvastatin and allopurinol rats were subjected to hyperuricemia, induced by the administration of yeast extract powder (21 g/kg/day) and oxonic acid potassium salt (200 mg/kg/day). The hyperuricemic rats were treated with 2.5, 5.0 or 10.0 mg/kg/day rosuvastatin orally for six weeks, while rats treated with allopurinol (53.57 mg/kg/day) were used as a positive control. The serum levels of NO and the gene expression levels of endothelial NO synthase in the aortic tissue increased, whereas the serum levels of UA, endothelin-1 and angiotensin II decreased in the hyperuricemic rats treated with rosuvastatin, particularly at a high rosuvastatin dose (10 mg/kg/day). In addition, the curative effect of the 10 mg/kg/day rosuvastatin group was evidently higher compared with the allopurinol group. Therefore, rosuvastatin may be a novel drug candidate for the treatment of hyperuricemia due to its endothelial protective properties.

  19. Adipose-derived stromal cell autologous transplantation ameliorates pulmonary arterial hypertension induced by shunt flow in rat models.

    PubMed

    Liu, Kai; Liu, Ruifang; Cao, Guangqing; Sun, Hourong; Wang, Xuping; Wu, Shuming

    2011-06-01

    Hyperkinetic pulmonary arterial hypertension (PAH) severely influences the success of operation for congenital heart disease and deteriorates the prognosis of disease. Adipose-derived stromal cell (ADSC) is a good alternative multipotent stem cell for regeneration medicine. PAH rat models were established by arteriovenous shunt and ADSCs were isolated, cultured, and labeled in vitro. Twelve weeks after shunt operation, rats received an injection of 5 × 10(7) ADSCs. Two weeks after transplantation, hemodynamic abnormality induced by the shunt flow and the hypertrophy of right ventricle were reversed, which was confirmed by invasive measurement and echocardiography examination. The PAH rats receiving cell transplantation demonstrated decreased remodeling of small arteries in the lung; immunohistochemistry analysis showed augmented expression of hepatocyte growth factor (HGF) and increased number of pulmonary small arteries. Western blot and real-time reverse transcriptase-polymerase chain reaction indicated that the protein and mRNA levels of HGF and endothelial nitric oxide synthase increased, respectively, in the lung after cell transplantation. Our results suggested that ADSC transplantation can ameliorate PAH induced by shunt flow by enhancing the expression of HGF and subsequently promoting angiogenesis in the injured lung tissue. PMID:20828291

  20. Icariin Inhibits Pulmonary Hypertension Induced by Monocrotaline through Enhancement of NO/cGMP Signaling Pathway in Rats

    PubMed Central

    Li, Li-sheng; Luo, Yun-mei; Liu, Juan; Zhang, Yu; Fu, Xiao-xia; Yang, Dan-li

    2016-01-01

    It has been reported that icariin (ICA) increased contents of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) by improving expression of endothelial nitric oxide synthase (eNOS) and inhibition of phosphodiesterase type 5 (PDE5). In addition, dysfunction of the NO/cGMP pathway may play a crucial role in the pathogenesis of pulmonary hypertension (PH). In this study, the potential protective effects of ICA on PH induced by monocrotaline (MCT, 50 mg/kg) singly subcutaneous injection were investigated and the possible mechanisms involved in NO/cGMP pathway were explored in male Sprague Dawley rats. The results showed that ICA (20, 40, and 80 mg/kg/d) treatment by intragastric administration could significantly ameliorate PH and upregulate the expression of eNOS gene and downregulate the expression of PDE5 gene in MCT-treated rats. Both ICA (40 mg/kg/d) and L-arginine (200 mg/kg/d), a precursor of NO as positive control, notably increased the contents of NO and cGMP in lung tissue homogenate, which were inversed by treatment with NG-nitro-L-arginine-methyl ester (L-NAME), a NOS inhibitor, and L-NAME-treatment could also inhibit the protective effects of ICA (40 mg/kg/d) on mean pulmonary artery pressure and artery remodeling and tends to inhibit right ventricle hypertrophy index. In summary, ICA is effective in protecting against MCT-induced PH in rats through enhancement of NO/cGMP signaling pathway in rats. PMID:27366192

  1. Effects of fixed-dose isosorbide dinitrate/hydralazine on diastolic function and exercise capacity in hypertension-induced diastolic heart failure.

    PubMed

    Wilson, Richard M; De Silva, Deepa S; Sato, Kaori; Izumiya, Yasuhiro; Sam, Flora

    2009-09-01

    Hypertension-induced diastolic heart failure accounts for a large proportion of all heart failure presentations. Hypertension also induces left ventricular (LV) hypertrophy. Fixed-dose isosorbide dinitrate/hydralazine (HISDN) decreased mortality in human systolic heart failure but it is unknown whether it improves maladaptive myocardial remodeling. We sought to test the hypothesis that chronic HISDN modulates LV hypertrophy and myocardial remodeling in hypertension-induced diastolic heart failure. FVB mice underwent either saline (n=18) or aldosterone (n=28) infusion. All underwent uninephrectomy and drank 1% salt water for 4 weeks. Mice were randomized after surgery to regular chow or chow containing HISDN (isosorbide dinitrate: 26 mg/kg per day; hydralazine: 50 mg/kg per day) for 4 weeks. Aldosterone infusion increased tail-cuff blood pressure (161+/-3 mm Hg) versus saline-infused mice (129+/-2 mm Hg). Aldosterone induced LV hypertrophy versus saline-infused mice (LV:body weight ratio: 4.2+/-0.1 versus 3.6+/-0.1 mg/g). HISDN attenuated the aldosterone-induced increased in systolic blood pressure (137+/-5 mm Hg) and also lowered blood pressure in saline-infused mice (114+/-2 mm Hg). However, HISDN did not cause LV hypertrophy regression in aldosterone-infused mice. Aldosterone increased LV end-diastolic dimensions that were not attenuated by HISDN. Similarly, neither aldosterone infusion nor HISDN affected LV end-systolic dimensions. LV ejection fraction and wet:dry lung ratio were not different between aldosterone-untreated and aldosterone-HISDN mice. However, mitral Doppler E/A ratio (a measure of diastolic function), exercise capacity, and plasma soluble vascular cell adhesion molecule 1 levels were improved in aldosterone-HISDN hearts. In conclusion, fixed-dose HISDN improved hypertension, diastolic function, and exercise capacity and reduced soluble vascular cell adhesion molecule 1 levels. There were no reductions in LV hypertrophy, cardiac fibrosis, or

  2. HDL and endothelial protection

    PubMed Central

    Tran-Dinh, A; Diallo, D; Delbosc, S; Varela-Perez, L Maria; Dang, QB; Lapergue, B; Burillo, E; Michel, JB; Levoye, A; Martin-Ventura, JL; Meilhac, O

    2013-01-01

    High-density lipoproteins (HDLs) represent a family of particles characterized by the presence of apolipoprotein A-I (apoA-I) and by their ability to transport cholesterol from peripheral tissues back to the liver. In addition to this function, HDLs display pleiotropic effects including antioxidant, anti-apoptotic, anti-inflammatory, anti-thrombotic or anti-proteolytic properties that account for their protective action on endothelial cells. Vasodilatation via production of nitric oxide is also a hallmark of HDL action on endothelial cells. Endothelial cells express receptors for apoA-I and HDLs that mediate intracellular signalling and potentially participate in the internalization of these particles. In this review, we will detail the different effects of HDLs on the endothelium in normal and pathological conditions with a particular focus on the potential use of HDL therapy to restore endothelial function and integrity. PMID:23488589

  3. Hypoxia activates 15-PGDH and its metabolite 15-KETE to promote pulmonary artery endothelial cells proliferation via ERK1/2 signalling

    PubMed Central

    Ma, Cui; Liu, Yun; Wang, Yanyan; Zhang, Chen; Yao, Hongmin; Ma, Jun; Zhang, Lei; Zhang, Dandan; Shen, Tingting; Zhu, Daling

    2014-01-01

    BACKGROUND AND PURPOSE Dysfunction and injury of endothelial cells in the pulmonary artery play critical roles in the hypertension induced by chronic hypoxia. One consequence of hypoxia is increased activity of 15-hydroxyprostaglandin dehydrogenase (PGDH). Here, we have explored, in detail, the effects of hypoxia on the proliferation of pulmonary artery endothelial cells. EXPERIMENTAL APPROACH We used bromodeoxyuridine incorporation, cell-cycle analysis, immunohistochemistry and Western blot analysis to study the effects of hypoxia, induced 15-PGDH) activity and its product, 15-keto-6Z, 8Z, 11Z, 13E-eicosatetraenoic acid (15-KETE), on endothelial cell proliferation. Scratch-wound and tube formation assays were also used to study migration of endothelial cells. KEY RESULTS 15-KETE increased DNA synthesis and enhanced the transition from the G0/G1 phase to the S phase in hypoxia. Inhibition of 15-PGDH or siRNA for 15-PGDH reversed these effects. 15-KETE also activated the ERK1/2 signalling pathway. 15-KETE-induced cell migration and tube formation were reversed by blocking ERK1/2, but not the p38 MAPK pathway. CONCLUSIONS AND IMPLICATIONS Hypoxia-induced endothelial proliferation and migration, an important underlying mechanism contributing to hypoxic pulmonary vascular remodelling, appears to be mediated by 15-PGDH and 15-KETE, via the ERK1/2 signalling pathway. PMID:24467360

  4. Evolution of endothelial keratoplasty.

    PubMed

    Price, Francis W; Price, Marianne O

    2013-11-01

    Endothelial keratoplasty has evolved into a popular alternative to penetrating keratoplasty (PK) for the treatment of endothelial dysfunction. Although the earliest iterations were challenging and were not widely adopted, the iteration known as Descemet stripping endothelial keratoplasty (DSEK) has gained widespread acceptance. DSEK combines a simplified technique for stripping dysfunctional endothelium from the host cornea and microkeratome dissection of the donor tissue, a step now commonly completed in advance by eye bank technicians. Studies show that a newer endothelial keratoplasty iteration, known as Descemet membrane endothelial keratoplasty (DMEK), provides an even faster and better visual recovery than DSEK does. In addition, DMEK significantly reduces the risk of immunologic graft rejection episodes compared with that in DSEK or in PK. Although the DMEK donor tissue, consisting of the bare endothelium and Descemet membrane without any stroma, is more challenging to prepare and position in the recipient eye, recent improvements in instrumentation and surgical techniques are increasing the ease and the reliability of the procedure. DSEK successfully mitigates 2 of the main liabilities of PK: ocular surface complications and structural problems (including induced astigmatism and perpetually weak wounds), whereas DMEK further mitigates the 2 principal remaining liabilities of PK: immunologic graft reactions and secondary glaucoma from prolonged topical corticosteroid use.

  5. HYPAZ: Hypertension Induced by Pazopanib

    ClinicalTrials.gov

    2016-01-04

    Renal Cell Carcinoma; Soft Tissue Sarcoma; Glioblastoma; Ovarian Cancer; Cervical Cancer; Breast Cancer; Non-small Cell Lung Cancer; Small Cell Lung Cancer; Pancreatic Cancer; Melanoma; Gastrointestinal Cancer

  6. PARP-inhibitor treatment prevents hypertension induced cardiac remodeling by favorable modulation of heat shock proteins, Akt-1/GSK-3β and several PKC isoforms.

    PubMed

    Deres, Laszlo; Bartha, Eva; Palfi, Anita; Eros, Krisztian; Riba, Adam; Lantos, Janos; Kalai, Tamas; Hideg, Kalman; Sumegi, Balazs; Gallyas, Ferenc; Toth, Kalman; Halmosi, Robert

    2014-01-01

    Spontaneously hypertensive rat (SHR) is a suitable model for studies of the complications of hypertension. It is known that activation of poly(ADP-ribose) polymerase enzyme (PARP) plays an important role in the development of postinfarction as well as long-term hypertension induced heart failure. In this study, we examined whether PARP-inhibitor (L-2286) treatment could prevent the development of hypertensive cardiopathy in SHRs. 6-week-old SHR animals were treated with L-2286 (SHR-L group) or placebo (SHR-C group) for 24 weeks. Wistar-Kyoto rats were used as aged-matched, normotensive controls (WKY group). Echocardiography was performed, brain-derived natriuretic peptide (BNP) activity and blood pressure were determined at the end of the study. We detected the extent of fibrotic areas. The amount of heat-shock proteins (Hsps) and the phosphorylation state of Akt-1(Ser473), glycogen synthase kinase (GSK)-3β(Ser9), forkhead transcription factor (FKHR)(Ser256), mitogen activated protein kinases (MAPKs), and protein kinase C (PKC) isoenzymes were monitored. The elevated blood pressure in SHRs was not influenced by PARP-inhibitor treatment. Systolic left ventricular function and BNP activity did not differ among the three groups. L-2286 treatment decreased the marked left ventricular (LV) hypertrophy which was developed in SHRs. Interstitial collagen deposition was also decreased by L-2286 treatment. The phosphorylation of extracellular signal-regulated kinase (ERK)1/2(Thr183-Tyr185), Akt-1(Ser473), GSK-3β(Ser9), FKHR(Ser256), and PKC ε(Ser729) and the level of Hsp90 were increased, while the activity of PKC α/βII(Thr638/641), ζ/λ(410/403) were mitigated by L-2286 administration. We could detect signs of LV hypertrophy without congestive heart failure in SHR groups. This alteration was prevented by PARP inhibition. Our results suggest that PARP-inhibitor treatment has protective effect already in the early stage of hypertensive myocardial remodeling. PMID

  7. Reactive oxygen species' role in endothelial dysfunction by electron paramagnetic resonance

    NASA Astrophysics Data System (ADS)

    Wassall, Cynthia D.

    % increase in ROS generation; this implies that higher ROS concentrations in sliced tissue indicate extraneous ROS generation not associated with the ROS stimulus of interest. We also investigated the role of ROS in chronic flow overload (CFO). Elevation of shear stress that increases production of vascular ROS has not been well investigated. We hypothesize that CFO increases ROS production mediated in part by NADPH oxidase, which leads to endothelial dysfunction. ROS production increased threefold in response to CFO. The endothelium dependent vasorelaxation was compromised in the CFO group. Treatment with apocynin significantly reduced ROS production in the vessel wall, preserved endothelial function, and inhibited expressions of p22/p47phox and NOX2/NOX4. The present data implicate NADPH oxidase produced ROS and eNOS uncoupling in endothelial dysfunction at 1 wk of CFO. In further work, a swine right ventricular hypertrophy (RVH) model induced by pulmonary artery (PA) banding was used to study right coronary artery (RCA) endothelial function and ROS level. Endothelial function was compromised in RCA of RVH as attributed to insufficient endothelial nitric oxide synthase cofactor tetrahydrobiopterin. In conclusion, stretch due to outward remodeling of RCA during RVH (at constant wall shear stress), similar to vessel stretch in hypertension, appears to induce ROS elevation, endothelial dysfunction, and an increase in basal tone. Finally, although hypertension-induced vascular stiffness and dysfunction are well established in patients and animal models, we hypothesize that stretch or distension due to hypertension and outward expansion is the cause of endothelial dysfunction mediated by angiotensin II type 1 (AT1) receptor in coronary arteries. The expression and activation of AT1 receptor and the production of ROS were up regulated and endothelial function deteriorated in the RCA. The acute inhibition of AT1 receptor and NADPH oxidase partially restored the endothelial

  8. 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.

  9. In Vitro Endothelialization Test of Biomaterials Using Immortalized Endothelial Cells

    PubMed Central

    Kono, Ken; Hiruma, Hitomi; Kobayashi, Shingo; Sato, Yoji; Tanaka, Masaru; Sawada, Rumi; Niimi, Shingo

    2016-01-01

    Functionalizing biomaterials with peptides or polymers that enhance recruitment of endothelial cells (ECs) can reduce blood coagulation and thrombosis. To assess endothelialization of materials in vitro, primary ECs are generally used, although the characteristics of these cells vary among the donors and change with time in culture. Recently, primary cell lines immortalized by transduction of simian vacuolating virus 40 large T antigen or human telomerase reverse transcriptase have been developed. To determine whether immortalized ECs can substitute for primary ECs in material testing, we investigated endothelialization on biocompatible polymers using three lots of primary human umbilical vein endothelial cells (HUVEC) and immortalized microvascular ECs, TIME-GFP. Attachment to and growth on polymer surfaces were comparable between cell types, but results were more consistent with TIME-GFP. Our findings indicate that TIME-GFP is more suitable for in vitro endothelialization testing of biomaterials. PMID:27348615

  10. Cytochrome P4501A1 Is Required for Vascular Dysfunction and Hypertension Induced by 2,3,7,8-Tetrachlorodibenzo-p-Dioxin

    PubMed Central

    Kopf, Phillip G.; Scott, Jason A.; Agbor, Larry N.; Boberg, Jason R.; Elased, Khalid M.; Huwe, Janice K.; Walker, Mary K.

    2010-01-01

    National Health and Nutrition Examination Survey data show an association between hypertension and exposure to dioxin-like halogenated aromatic hydrocarbons (HAHs). Furthermore, chronic exposure of mice to the prototypical HAH, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), induces reactive oxygen species (ROS), endothelial dysfunction, and hypertension. Because TCDD induces cytochrome P4501A1 (CYP1A1) and CYP1A1 can increase ROS, we tested the hypothesis that TCDD-induced endothelial dysfunction and hypertension are mediated by CYP1A1. CYP1A1 wild-type (WT) and knockout (KO) mice were fed one control or TCDD-containing pill (180 ng TCDD/kg, 5 days/week) for 35 days (n = 10–14/genotype/treatment). Blood pressure was monitored by radiotelemetry, and liver TCDD concentration, CYP1A1 induction, ROS, and aortic reactivity were measured at 35 days. TCDD accumulated to similar levels in livers of both genotypes. TCDD induced CYP1A1 in endothelium of aorta and mesentery without detectable expression in the vessel wall. TCDD also induced superoxide anion production, measured by NADPH-dependent lucigenin luminescence, in aorta, heart, and kidney of CYP1A1 WT mice but not KO mice. In contrast, TCDD induced hydrogen peroxide, measured by amplex red assay, to similar levels in aorta of CYP1A1 WT and KO mice but not in heart or kidney. TCDD reduced acetylcholine-dependent vasorelaxation in aortic rings of CYP1A1 WT mice but not in KO mice. Finally, TCDD steadily increased blood pressure after 15 days, which plateaued after 25 days (+20 mmHg) in CYP1A1 WT mice but failed to alter blood pressure in KO mice. These results demonstrate that CYP1A1 is required for TCDD-induced cardiovascular superoxide anion production, endothelial dysfunction, and hypertension. PMID:20634294

  11. Reactive oxygen species' role in endothelial dysfunction by electron paramagnetic resonance

    NASA Astrophysics Data System (ADS)

    Wassall, Cynthia D.

    % increase in ROS generation; this implies that higher ROS concentrations in sliced tissue indicate extraneous ROS generation not associated with the ROS stimulus of interest. We also investigated the role of ROS in chronic flow overload (CFO). Elevation of shear stress that increases production of vascular ROS has not been well investigated. We hypothesize that CFO increases ROS production mediated in part by NADPH oxidase, which leads to endothelial dysfunction. ROS production increased threefold in response to CFO. The endothelium dependent vasorelaxation was compromised in the CFO group. Treatment with apocynin significantly reduced ROS production in the vessel wall, preserved endothelial function, and inhibited expressions of p22/p47phox and NOX2/NOX4. The present data implicate NADPH oxidase produced ROS and eNOS uncoupling in endothelial dysfunction at 1 wk of CFO. In further work, a swine right ventricular hypertrophy (RVH) model induced by pulmonary artery (PA) banding was used to study right coronary artery (RCA) endothelial function and ROS level. Endothelial function was compromised in RCA of RVH as attributed to insufficient endothelial nitric oxide synthase cofactor tetrahydrobiopterin. In conclusion, stretch due to outward remodeling of RCA during RVH (at constant wall shear stress), similar to vessel stretch in hypertension, appears to induce ROS elevation, endothelial dysfunction, and an increase in basal tone. Finally, although hypertension-induced vascular stiffness and dysfunction are well established in patients and animal models, we hypothesize that stretch or distension due to hypertension and outward expansion is the cause of endothelial dysfunction mediated by angiotensin II type 1 (AT1) receptor in coronary arteries. The expression and activation of AT1 receptor and the production of ROS were up regulated and endothelial function deteriorated in the RCA. The acute inhibition of AT1 receptor and NADPH oxidase partially restored the endothelial

  12. [Medical significance of endothelial glycocalyx].

    PubMed

    Frati-Munari, Alberto C

    2013-01-01

    Endothelial glycocalyx is a layer composed by glycosaminoglycans, proteoglycans and glycoproteins attached to the vascular endothelial luminal surface. It has several physiological roles: shear stress mechanotransduction to the endothelial cells, regulation of fluids and macromolecules vascular permeability, of coagulation cascade activation and fibrinolysis, and protects the endothelium from platelets and leukocytes adhesion. In general, glycocalyx protects vascular wall against pathogenic insults. The glycocalyx may be damaged by abnormal shear stress, reactive oxygen species, hypernatremia, hyperglycemia, hypercholesterolemia and inflammatory molecules, resulting in endothelial dysfunction, enhanced vascular permeability, lipoproteins leakage to subendothelial space, activation of plasma coagulation, and increased adherence of platelets and leukocytes to the endothelial cells. Shredding of glycocalyx appears as an important initial step in the pathophysiology of vascular diseases.

  13. Liver Sinusoidal Endothelial Cells.

    PubMed

    Sørensen, Karen Kristine; Simon-Santamaria, Jaione; McCuskey, Robert S; Smedsrød, Bård

    2015-10-01

    The liver sinusoidal endothelial cell (LSEC) forms the fenestrated wall of the hepatic sinusoid and functions as a control post regulating and surveying the trafficking of molecules and cells between the liver parenchyma and the blood. The cell acts as a scavenger cell responsible for removal of potential dangerous macromolecules from blood, and is increasingly acknowledged as an important player in liver immunity. This review provides an update of the major functions of the LSEC, including its role in plasma ultrafiltration and regulation of the hepatic microcirculation, scavenger functions, immune functions, and role in liver aging, as well as issues that are either undercommunicated or confusingly dealt with in the literature. These include metabolic functions, including energy metabolic interplay between the LSEC and the hepatocyte, and adequate ways of identifying and distinguishing the cells.

  14. Endothelial-regenerating cells: an expanding universe.

    PubMed

    Steinmetz, Martin; Nickenig, Georg; Werner, Nikos

    2010-03-01

    Atherosclerosis is the most common cause for cardiovascular diseases and is based on endothelial dysfunction. A growing body of evidence suggests the contribution of bone marrow-derived endothelial progenitor cells, monocytic cells, and mature endothelial cells to vessel formation and endothelial rejuvenation. To this day, various subsets of these endothelial-regenerating cells have been identified according to cellular origin, phenotype, and properties in vivo and in vitro. However, the definition and biology, especially of endothelial progenitor cells, is complex and under heavy debate. In this review, we focus on current definitions of endothelial progenitor cells, highlight the clinical relevance of endothelial-regenerating cells, and provide new insights into cell-cell interactions involved in endothelial cell rejuvenation.

  15. Endothelial function in obstructive sleep apnea.

    PubMed

    Atkeson, Amy; Yeh, Susie Yim; Malhotra, Atul; Jelic, Sanja

    2009-01-01

    Untreated obstructive sleep apnea (OSA) is an independent risk factor for hypertension, myocardial infarction, and stroke. The repetitive hypoxia/reoxygenation and sleep fragmentation associated with OSA impair endothelial function. Endothelial dysfunction, in turn, may mediate increased risk for cardiovascular diseases. Specifically, in OSA, endothelial nitric oxide availability and repair capacity are reduced, whereas oxidative stress and inflammation are enhanced. Treatment of OSA improves endothelial vasomotor tone and reduces inflammation. We review the evidence and possible mechanisms of endothelial dysfunction as well as the effect of treatment on endothelial function in OSA.

  16. Estetrol Modulates Endothelial Nitric Oxide Synthesis in Human Endothelial Cells

    PubMed Central

    Montt-Guevara, Maria Magdalena; Giretti, Maria Silvia; Russo, Eleonora; Giannini, Andrea; Mannella, Paolo; Genazzani, Andrea Riccardo; Genazzani, Alessandro David; Simoncini, Tommaso

    2015-01-01

    Estetrol (E4) is a natural human estrogen that is present at high concentrations during pregnancy. E4 has been reported to act as an endogenous estrogen receptor modulator, exerting estrogenic actions on the endometrium or the central nervous system but presenting antagonistic effects on the breast. Due to these characteristics, E4 is currently being developed for a number of clinical applications, including contraception and menopausal hormone therapy. Endothelial nitric oxide (NO) is a key player for vascular function and disease during pregnancy and throughout aging in women. Endothelial NO is an established target of estrogens that enhance its formation in human endothelial cells. We here addressed the effects of E4 on the activity and expression of the endothelial nitric oxide synthase (eNOS) in cultured human umbilical vein endothelial cells (HUVEC). E4 stimulated the activation of eNOS and NO secretion in HUVEC. E4 was significantly less effective compared to E2, and a peculiar concentration-dependent effect was found, with higher amounts of E4 being less effective than lower concentrations. When E2 was combined with E4, an interesting pattern was noted. E4 antagonized NO synthesis induced by pregnancy-like E2 concentrations. However, E4 did not impede the modest induction of NO synthesis associated with postmenopausal-like E2 levels. These results support the hypothesis that E4 may be a regulator of NO synthesis in endothelial cells and raise questions on its peculiar signaling in this context. Our results may be useful to interpret the role of E4 during human pregnancy and possibly to help develop this interesting steroid for clinical use. PMID:26257704

  17. Estetrol Modulates Endothelial Nitric Oxide Synthesis in Human Endothelial Cells.

    PubMed

    Montt-Guevara, Maria Magdalena; Giretti, Maria Silvia; Russo, Eleonora; Giannini, Andrea; Mannella, Paolo; Genazzani, Andrea Riccardo; Genazzani, Alessandro David; Simoncini, Tommaso

    2015-01-01

    Estetrol (E4) is a natural human estrogen that is present at high concentrations during pregnancy. E4 has been reported to act as an endogenous estrogen receptor modulator, exerting estrogenic actions on the endometrium or the central nervous system but presenting antagonistic effects on the breast. Due to these characteristics, E4 is currently being developed for a number of clinical applications, including contraception and menopausal hormone therapy. Endothelial nitric oxide (NO) is a key player for vascular function and disease during pregnancy and throughout aging in women. Endothelial NO is an established target of estrogens that enhance its formation in human endothelial cells. We here addressed the effects of E4 on the activity and expression of the endothelial nitric oxide synthase (eNOS) in cultured human umbilical vein endothelial cells (HUVEC). E4 stimulated the activation of eNOS and NO secretion in HUVEC. E4 was significantly less effective compared to E2, and a peculiar concentration-dependent effect was found, with higher amounts of E4 being less effective than lower concentrations. When E2 was combined with E4, an interesting pattern was noted. E4 antagonized NO synthesis induced by pregnancy-like E2 concentrations. However, E4 did not impede the modest induction of NO synthesis associated with postmenopausal-like E2 levels. These results support the hypothesis that E4 may be a regulator of NO synthesis in endothelial cells and raise questions on its peculiar signaling in this context. Our results may be useful to interpret the role of E4 during human pregnancy and possibly to help develop this interesting steroid for clinical use. PMID:26257704

  18. How cholesterol regulates endothelial biomechanics

    PubMed Central

    Hong, Zhongkui; Staiculescu, Marius C.; Hampel, Paul; Levitan, Irena; Forgacs, Gabor

    2012-01-01

    As endothelial cells form the barrier between blood flow and surrounding tissue, many of their functions depend on mechanical integrity, in particular those of the plasma membrane. As component and organizer of the plasma membrane, cholesterol is a regulator of cellular mechanical properties. Disruption of cholesterol balance leads to impairment of endothelial functions and eventually to disease. The mechanical properties of the membrane are strongly affected by the cytoskeleton. As Phosphatidylinositol-4,5-bisphosphate (PIP2) is a key mediator between the membrane and cytoskeleton, it also affects cellular biomechanical properties. Typically, PIP2 is concentrated in cholesterol-rich microdomains, such as caveolae and lipid rafts, which are particularly abundant in the endothelial plasma membrane. We investigated the connection between cholesterol and PIP2 by extracting membrane tethers from bovine aortic endothelial cells (BAEC) at different cholesterol levels and PIP2 conditions. Our results suggest that in BAEC the role of PIP2, as a mediator of membrane-cytoskeleton adhesion, is regulated by cholesterol. Our findings confirm the specific role of cholesterol in endothelial cells and may have implications for cholesterol-dependent vascular pathologies. PMID:23162471

  19. Regulation of endothelial permeability by second messengers.

    PubMed

    Siflinger-Birnboim, A; Malik, A B

    1996-02-01

    The mechanisms by which mediators such as oxidants released by neutrophil (PMN) activation increase endothelial permeability are poorly understood. The focus of this article is to identify some of these mechanisms. Studies using endothelial cell monolayers in culture have shown that PMN activation increases endothelial permeability both in the presence and absence of PMN-endothelial monolayer contact. Hydrogen peroxide (H2O2), an oxidant released by PMN activation, plays an important role in PMN-induced increases in endothelial permeability. The results of these studies suggest that, as with other mediators of inflammation (e.g., histamine, thrombin) the mechanism of H2O2-induced increase in endothelial permeability involves activation of endothelial protein kinase C (PKC) and increase in endothelial cytosolic Ca2+.

  20. Evaluation of photosynthetic electrons derivation by exogenous redox mediators.

    PubMed

    Longatte, Guillaume; Fu, Han-Yi; Buriez, Olivier; Labbé, Eric; Wollman, Francis-André; Amatore, Christian; Rappaport, Fabrice; Guille-Collignon, Manon; Lemaître, Frédéric

    2015-10-01

    Oxygenic photosynthesis is the complex process that occurs in plants or algae by which the energy from the sun is converted into an electrochemical potential that drives the assimilation of carbon dioxide and the synthesis of carbohydrates. Quinones belong to a family of species commonly found in key processes of the Living, like photosynthesis or respiration, in which they act as electron transporters. This makes this class of molecules a popular candidate for biofuel cell and bioenergy applications insofar as they can be used as cargo to ship electrons to an electrode immersed in the cellular suspension. Nevertheless, such electron carriers are mostly selected empirically. This is why we report on a method involving fluorescence measurements to estimate the ability of seven different quinones to accept photosynthetic electrons downstream of photosystem II, the first protein complex in the light-dependent reactions of oxygenic photosynthesis. To this aim we use a mutant of Chlamydomonas reinhardtii, a unicellular green alga, impaired in electron downstream of photosystem II and assess the ability of quinones to restore electron flow by fluorescence. In this work, we defined and extracted a "derivation parameter" D that indicates the derivation efficiency of the exogenous quinones investigated. D then allows electing 2,6-dichlorobenzoquinone, 2,5-dichlorobenzoquinone and p-phenylbenzoquinone as good candidates. More particularly, our investigations suggested that other key parameters like the partition of quinones between different cellular compartments and their propensity to saturate these various compartments should also be taken into account in the process of selecting exogenous quinones for the purpose of deriving photoelectrons from intact algae.

  1. Redox-mediated reactions of vinylferrocene: toward redox auxiliaries.

    PubMed

    Wiles, Alan A; Zhang, Xiaolu; Fitzpatrick, Brian; Long, De-Liang; Macgregor, Stuart A; Cooke, Graeme

    2016-05-01

    Chemical redox reactions have been exploited to transform unreactive vinylferrocene into a powerful dienophile for the Diels-Alder reaction and reactive substrate for thiol addition reactions upon conversion to its ferrocenium state. We have further investigated the ability of these reactions to facilitate redox-auxiliary-like reactivity by further hydrogenolyisis of the Diels-Alder adduct to the corresponding cyclopentane derivative.

  2. Evaluation of photosynthetic electrons derivation by exogenous redox mediators.

    PubMed

    Longatte, Guillaume; Fu, Han-Yi; Buriez, Olivier; Labbé, Eric; Wollman, Francis-André; Amatore, Christian; Rappaport, Fabrice; Guille-Collignon, Manon; Lemaître, Frédéric

    2015-10-01

    Oxygenic photosynthesis is the complex process that occurs in plants or algae by which the energy from the sun is converted into an electrochemical potential that drives the assimilation of carbon dioxide and the synthesis of carbohydrates. Quinones belong to a family of species commonly found in key processes of the Living, like photosynthesis or respiration, in which they act as electron transporters. This makes this class of molecules a popular candidate for biofuel cell and bioenergy applications insofar as they can be used as cargo to ship electrons to an electrode immersed in the cellular suspension. Nevertheless, such electron carriers are mostly selected empirically. This is why we report on a method involving fluorescence measurements to estimate the ability of seven different quinones to accept photosynthetic electrons downstream of photosystem II, the first protein complex in the light-dependent reactions of oxygenic photosynthesis. To this aim we use a mutant of Chlamydomonas reinhardtii, a unicellular green alga, impaired in electron downstream of photosystem II and assess the ability of quinones to restore electron flow by fluorescence. In this work, we defined and extracted a "derivation parameter" D that indicates the derivation efficiency of the exogenous quinones investigated. D then allows electing 2,6-dichlorobenzoquinone, 2,5-dichlorobenzoquinone and p-phenylbenzoquinone as good candidates. More particularly, our investigations suggested that other key parameters like the partition of quinones between different cellular compartments and their propensity to saturate these various compartments should also be taken into account in the process of selecting exogenous quinones for the purpose of deriving photoelectrons from intact algae. PMID:26051794

  3. Endothelial Caveolar Subcellular Domain Regulation of Endothelial Nitric Oxide Synthase

    PubMed Central

    Ramadoss, Jayanth; Pastore, Mayra B.; Magness, Ronald R.

    2015-01-01

    SUMMARY Complex regulatory processes alter the activity of endothelial nitric oxide synthase (eNOS) leading to nitric oxide (NO) production by endothelial cells under various physiological states. These complex processes require specific sub-cellular eNOS partitioning between plasma membrane caveolar domains and non-caveolar compartments.eNOS translocation from the plasma membrane to intracellular compartments is important for eNOS activation and subsequent NO biosynthesis. We present data reviewing and interpreting information: 1) the coupling of endothelial plasma membrane receptor systems in the caveolar structure relative to eNOS trafficking; 2) how eNOS trafficking relates to specific protein-protein interaction for inactivation and activation of eNOS; and 3) how these complex mechanisms confer specific subcellular location relative to eNOS multi-site phosphorylation and signaling.Dysfunction in regulation of eNOS activation may contribute to several disease states; in particular gestational endothelial abnormalities (preeclampsia, gestational diabetes, etc) that have life-long deleterious health consequences that predispose the offspring to develop hypertensive disease, type II diabetes and adiposity.1 PMID:23745825

  4. Retinal Endothelial Cell Apoptosis Stimulates Recruitment of Endothelial Progenitor Cells

    PubMed Central

    Bhatwadekar, Ashay D.; Glenn, Josephine V.; Curtis, Tim M.; Grant, Maria B.; Stitt, Alan W.; Gardiner, Tom A.

    2013-01-01

    Purpose Bone marrow–derived endothelial progenitor cells (EPCs) contribute to vascular repair although it is uncertain how local endothelial cell apoptosis influences their reparative function. This study was conducted to determine how the presence of apoptotic bodies at sites of endothelial damage may influence participation of EPCs in retinal microvascular repair. Methods Microlesions of apoptotic cell death were created in monolayers of retinal microvascular endothelial cells (RMECs) by using the photodynamic drug verteporfin. The adhesion of early-EPCs to these lesions was studied before detachment of the apoptotic cells or after their removal from the wound site. Apoptotic bodies were fed to normal RMECs and mRNA levels for adhesion molecules were analyzed. Results Endothelial lesions where apoptotic bodies were left attached at the wound site showed a fivefold enhancement in EPC recruitment (P < 0.05) compared with lesions where the apoptotic cells had been removed. In intact RMEC monolayers exposed to apoptotic bodies, expression of ICAM, VCAM, and E-selectin was upregulated by 5- to 15-fold (P < 0.05– 0.001). EPCs showed a characteristic chemotactic response (P < 0.05) to conditioned medium obtained from apoptotic bodies, whereas analysis of the medium showed significantly increased levels of VEGF, IL-8, IL-6, and TNF-α when compared to control medium; SDF-1 remained unchanged. Conclusions The data indicate that apoptotic bodies derived from retinal capillary endothelium mediate release of proangiogenic cytokines and chemokines and induce adhesion molecule expression in a manner that facilitates EPC recruitment. PMID:19474402

  5. Analysis of Endothelial Barrier Function In Vitro

    PubMed Central

    Wang, Yuping; Alexander, J. Steven

    2016-01-01

    Increased microvascular solute permeability underlies many forms of pathophysiological conditions, including inflammation. Endothelial monolayer cultures provide an excellent model system which allows systemic and mechanistic study of endothelial barrier function and paracellular permeability in vitro. The endothelial-specific complexus adherens junction protein VE-cadherin and their intracellular complex form pericellular structures along the cell borders which are critical to regulate endothelial barrier function by controlling pericellular permeability of vasculature. Here, we describe methods for both visualizing and quantifying junctional permeability and barrier changes in endothelial monolayers in vitro. PMID:21874457

  6. 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. PMID:17893694

  7. Analysis of endothelial barrier function in vitro.

    PubMed

    Wang, Yuping; Alexander, J Steven

    2011-01-01

    Increased microvascular solute permeability underlies many forms of pathophysiological conditions, including inflammation. Endothelial monolayer cultures provide an excellent model system which allows systemic and mechanistic study of endothelial barrier function and paracellular permeability in vitro. The endothelial-specific complexus adherens junction protein VE-cadherin and their intracellular complex form pericellular structures along the cell borders which are critical to regulate endothelial barrier function by controlling pericellular permeability of vasculature. Here, we describe methods for both visualizing and quantifying junctional permeability and barrier changes in endothelial monolayers in vitro. PMID:21874457

  8. Endothelial Plasticity: Shifting Phenotypes through Force Feedback

    PubMed Central

    Krenning, Guido; Barauna, Valerio G.; Krieger, José E.; Harmsen, Martin C.; Moonen, Jan-Renier A. J.

    2016-01-01

    The endothelial lining of the vasculature is exposed to a large variety of biochemical and hemodynamic stimuli with different gradients throughout the vascular network. Adequate adaptation requires endothelial cells to be highly plastic, which is reflected by the remarkable heterogeneity of endothelial cells in tissues and organs. Hemodynamic forces such as fluid shear stress and cyclic strain are strong modulators of the endothelial phenotype and function. Although endothelial plasticity is essential during development and adult physiology, proatherogenic stimuli can induce adverse plasticity which contributes to disease. Endothelial-to-mesenchymal transition (EndMT), the hallmark of endothelial plasticity, was long thought to be restricted to embryonic development but has emerged as a pathologic process in a plethora of diseases. In this perspective we argue how shear stress and cyclic strain can modulate EndMT and discuss how this is reflected in atherosclerosis and pulmonary arterial hypertension. PMID:26904133

  9. Endothelial dysfunction: a comprehensive appraisal

    PubMed Central

    Esper, Ricardo J; Nordaby, Roberto A; Vilariño, Jorge O; Paragano, Antonio; Cacharrón, José L; Machado, Rogelio A

    2006-01-01

    The endothelium is a thin monocelular layer that covers all the inner surface of the blood vessels, separating the circulating blood from the tissues. It is not an inactive organ, quite the opposite. It works as a receptor-efector organ and responds to each physical or chemical stimulus with the release of the correct substance with which it may maintain vasomotor balance and vascular-tissue homeostasis. It has the property of producing, independently, both agonistic and antagonistic substances that help to keep homeostasis and its function is not only autocrine, but also paracrine and endocrine. In this way it modulates the vascular smooth muscle cells producing relaxation or contraction, and therefore vasodilatation or vasoconstriction. The endothelium regulating homeostasis by controlling the production of prothrombotic and antithrombotic components, and fibrynolitics and antifibrynolitics. Also intervenes in cell proliferation and migration, in leukocyte adhesion and activation and in immunological and inflammatory processes. Cardiovascular risk factors cause oxidative stress that alters the endothelial cells capacity and leads to the so called endothelial "dysfunction" reducing its capacity to maintain homeostasis and leads to the development of pathological inflammatory processes and vascular disease. There are different techniques to evaluate the endothelium functional capacity, that depend on the amount of NO produced and the vasodilatation effect. The percentage of vasodilatation with respect to the basal value represents the endothelial functional capacity. Taking into account that shear stress is one of the most important stimulants for the synthesis and release of NO, the non-invasive technique most often used is the transient flow-modulate "endothelium-dependent" post-ischemic vasodilatation, performed on conductance arteries such as the brachial, radial or femoral arteries. This vasodilatation is compared with the vasodilatation produced by drugs that

  10. Salt controls endothelial and vascular phenotype.

    PubMed

    Kusche-Vihrog, Kristina; Schmitz, Boris; Brand, Eva

    2015-03-01

    High salt (NaCl) intake promotes the development of vascular diseases independent of a rise in blood pressure, whereas reduction of salt consumption has beneficial effects for the arterial system. This article summarizes our current understanding of the molecular mechanisms of high salt-induced alterations of the endothelial phenotype, the impact of the individual endothelial genotype, and the overall vascular phenotype. We focus on the endothelial Na(+) channel (EnNaC)-controlled nanomechanical properties of the endothelium, since high Na(+) leads to an EnNaC-induced Na(+)-influx and subsequent stiffening of endothelial cells. The mechanical stiffness of the endothelial cell (i.e., the endothelial phenotype) plays a crucial role as it controls the production of the endothelium-derived vasodilator nitric oxide (NO) which directly affects the tone of the vascular smooth muscle cells. In contrast to soft endothelial cells, stiff endothelial cells release reduced amounts of NO, the hallmark of endothelial dysfunction. This endothelium-born process is followed by the development of arterial stiffness (i.e., the vascular phenotype), predicting the development of vascular end-organ damage such as myocardial infarction, stroke, and renal impairment. In this context, we outline the potential clinical implication of direct (amiloride) and indirect (spironolactone) EnNaC inhibition on vascular function. However, interindividual differences exist in the response to high salt intake which involves different endothelial genotypes. Thus, selected genes and genetic variants contributing to the development of salt-induced endothelial dysfunction and hypertension are discussed. In this review, we focus on the role of salt in endothelial and vascular (dys)function and the link between salt-induced changes of the endothelial and vascular phenotype and its clinical implications.

  11. Culture of human endothelial cells.

    PubMed

    Gallicchio, M A

    2001-01-01

    Endothelial cells line the luminal surface of all blood vessels in the body. The endothelial surface in adult humans is composed of approximately l-6×l0(13) cells and covers an area of 1-7 m(2). Endothelium serves many functions, including fluid and solute exchange through cell contraction, provision of an antithrombogenic surface through tissue plasminogen activator (tPA) and prostacyclin release, synthesis of angiogenic factors such as adenosine, allowance of leukocyte trafficking through adhesion molecule synthesis, presentation of antigens to the immune system, maintenance of vascular tone through nitric oxide and endothelin synthesis, and metabolism of circulating molecules through the release of enzymes such as lipoprotein lipase. PMID:21340938

  12. Do incretins improve endothelial function?

    PubMed Central

    2014-01-01

    An impaired endothelial function has been recognized in the early stage of atherosclerosis, and is a major factor affecting the future development of cardiovascular events. Type 2 diabetes mellitus (T2DM) is widely prevalent, and is one of the most important risk factors for cardiovascular disease. T2DM is associated with increases in both morbidity and mortality, particularly from cardiovascular disease. New therapies based on the incretin hormone and its actions are now becoming widely used, and appear to offer advantages over conventional therapies by keeping the body weight steady and limiting hypoglycemia, while also achieving attractive glycemic control. However, there is little data available about the effects of incretins on the cardiovascular system. This review will focus on the effects of incretin therapies, including glucagon-like peptide-1 (GLP-1) analogs and dipeptidyl peptidase (DPP)-4 inhibitors, on the endothelial function, and will discuss the potential mechanisms underlying these effects. PMID:24428883

  13. Flow-Mediated Endothelial Mechanotransduction

    PubMed Central

    Davies, Peter F.

    2011-01-01

    Mechanical forces associated with blood flow play important roles in the acute control of vascular tone, the regulation of arterial structure and remodeling, and the localization of atherosclerotic lesions. Major regulation of the blood vessel responses occurs by the action of hemodynamic shear stresses on the endothelium. The transmission of hemodynamic forces throughout the endothelium and the mechanotransduction mechanisms that lead to biophysical, biochemical, and gene regulatory responses of endothelial cells to hemodynamic shear stresses are reviewed. PMID:7624393

  14. ENDOTHELIAL CELLS IN ALLOGRAFT REJECTION

    PubMed Central

    Al-Lamki, Rafia S.; Bradley, John R.; Pober, Jordan S.

    2008-01-01

    In organ transplantation, blood borne cells and macromolecules (e.g. antibodies) of the host immune system are brought into direct contact with the endothelial cell (EC) lining of graft vessels. In this location, graft ECs play several roles in allograft rejection, including the initiation of rejection responses by presentation of alloantigen to circulating T cells; the development of inflammation and thrombosis; and as targets of injury and agents of repair. PMID:19034000

  15. 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

  16. Replication of human endothelial cells in culture.

    PubMed

    Lewis, L J; Hoak, J C; Maca, R D; Fry, G L

    1973-08-01

    Investigative studies dealing with the properties and functions of endothelial cells have been hampered because there has been little or no success in the isolation, growth, and passage of individual cells in large numbers. We have developed a system whereby pure cultures of endothelial cells derived from umbilical veins can be subcultured for at least five serial passages. Many facets of endothelial function and interaction can be evaluated with the use of this new adaptive system of isolation and culture. PMID:4718112

  17. Renal Endothelial Dysfunction in Diabetic Nephropathy

    PubMed Central

    Cheng, Huifang; Harris, Raymond C.

    2015-01-01

    Endothelial dysfunction has been posited to play an important role in the pathogenesis of diabetic nephropathy (DN). Due to the heterogeneity of endothelial cells (ECs), it is difficult to generalize about endothelial responses to diabetic stimuli. At present, there are limited techniques fordirectly measuring EC function in vivo, so diagnosis of endothelial disorders still largely depends on indirect assessment of mediators arising from EC injury. In the kidney microcirculation, both afferent and efferent arteries, arterioles and glomerular endothelial cells (GEnC) have all been implicated as targets of diabetic injury. Both hyperglycemia per se, as well as the metabolic consequences of glucose dysregulation, are thought to lead to endothelial cell dysfunction. In this regard, endothelial nitric oxide synthase (eNOS) plays a central role in EC dysfunction. Impaired eNOS activity can occur at numerous levels, including enzyme uncoupling, post-translational modifications, internalization and decreased expression. Reduced nitric oxide (NO) bioavailability exacerbates oxidative stress, further promoting endothelial dysfunction and injury. The injured ECs may then function as active signal transducers of metabolic, hemodynamic and inflammatory factors that modify the function and morphology of the vessel wall and interact with adjacent cells, which may activate a cascade of inflammatory and proliferative and profibrotic responses in progressive DN. Both pharmacological approaches and potential regenerative therapies hold promise for restoration of impaired endothelial cells in diabetic nephropathy. PMID:24720460

  18. Molecular mechanisms that control endothelial cell contacts.

    PubMed

    Vestweber, D

    2000-02-01

    Endothelial cell contacts control the permeability of the blood vessel wall. This allows the endothelium to form a barrier for solutes, macromolecules, and leukocytes between the vessel lumen and the interstitial space. Loss of this barrier function in pathophysiological situations can lead to extracellular oedema. The ability of leukocytes to enter tissue at sites of inflammation is dependent on molecular mechanisms that allow leukocytes to adhere to the endothelium and to migrate through the endothelial cell layer and the underlying basal lamina. It is a commonly accepted working hypothesis that inter-endothelial cell contacts are actively opened and closed during this process. Angiogenesis is another important process that requires well-controlled regulation of inter-endothelial cell contacts. The formation of new blood vessels by sprouting from pre-existing vessels depends on the loosening of established endothelial cell contacts and the migration of endothelial cells that form the outgrowing sprouts. This review focuses on the molecular composition of endothelial cell surface proteins and proteins of the cytoskeletal undercoat of the plasma membrane at sites of inter-endothelial cell contacts and discusses the current knowledge about the potential role of such molecules in the regulation of endothelial cell contacts. PMID:10685062

  19. Progenitor endothelial cell involvement in Alzheimer's disease

    SciTech Connect

    Budinger, Thomas F.

    2003-05-01

    There is compelling evidence that endothelial cells of the brain and periphery are dysfunctional in Alzheimer's Disease. There is evidence for a fundamental defect in, or abnormal aging of, endothelial progenitor cells in atherosclerosis. The possibility that endothelial cell defects are a primary cause for Alzheimer's Disease or other dementias can be researched by molecular and cell biology studies as well as cell trafficking studies using recently demonstrated molecular imaging methods. The evidence for abnormal endothelial function and the methods to explore this hypothesis are presented.

  20. Endothelial cells in health and disease.

    PubMed

    Eckers, Anna; Haendeler, Judith

    2015-05-10

    According to the World Health Organization, from 2014, cardiovascular diseases (CVD) are the number one cause of death worldwide. One of the key players in maintaining proper cardiovascular function is the endothelium, the inner layer of all blood vessels. This monolayer of cells on one hand serves as a barrier between blood and the surrounding tissue and on the other hand regulates many aspects of vessel function. Therefore, it is not surprising that interventions reducing the risk for CVD improve endothelial function. There is a clear correlation between endothelial dysfunction, in which the endothelial homeostasis is disturbed, and the development and progression of many CVD. Thus, the development of diagnostic tools for early detection of disturbances in endothelial homeostasis or interventions aimed at improving endothelial function after insults require a comprehensive knowledge not only of the cellular reactions to the positive or negative stimuli but also of the molecular mechanisms relaying these responses. Thus, this Forum on "endothelial cells in health and disease" focuses on key molecules and processes intimately involved in endothelial cell function and covers areas from endothelial nitric oxide synthase-dependent processes, over the group of Phox-Bem1 domain proteins, cytochrome P450 epoxygenase-derived metabolites, and pre-mRNA splicing to microRNAs. Finally, one has to conclude that keeping endothelial homeostasis is the central key for a healthy long life of the human individual.

  1. Comparison of endothelial evaluation techniques.

    PubMed

    Langston, R H; Roisman, T S

    1981-01-01

    Comparative evaluation of the corneal endothelium with the Heyer-Schulte specular photomicroscope, the McIntyre CEB reticle affixed to a slitlamp, and a slitlamp alone found the reticle-slitlamp combination to give results within a 10% average of endothelial cell counts determined with the specular microscope. The reticle also compared favorably in time and cost savings. All three methods of corneal evaluation were effective for observation of polymegathism. Because of its lower magnification, the slitlamp without the reticle was best suited for evaluation of cornea guttata. PMID:7287565

  2. Vascular endothelial dysfunction and pharmacological treatment

    PubMed Central

    Su, Jin Bo

    2015-01-01

    The endothelium exerts multiple actions involving regulation of vascular permeability and tone, coagulation and fibrinolysis, inflammatory and immunological reactions and cell growth. Alterations of one or more such actions may cause vascular endothelial dysfunction. Different risk factors such as hypercholesterolemia, homocystinemia, hyperglycemia, hypertension, smoking, inflammation, and aging contribute to the development of endothelial dysfunction. Mechanisms underlying endothelial dysfunction are multiple, including impaired endothelium-derived vasodilators, enhanced endothelium-derived vasoconstrictors, over production of reactive oxygen species and reactive nitrogen species, activation of inflammatory and immune reactions, and imbalance of coagulation and fibrinolysis. Endothelial dysfunction occurs in many cardiovascular diseases, which involves different mechanisms, depending on specific risk factors affecting the disease. Among these mechanisms, a reduction in nitric oxide (NO) bioavailability plays a central role in the development of endothelial dysfunction because NO exerts diverse physiological actions, including vasodilation, anti-inflammation, antiplatelet, antiproliferation and antimigration. Experimental and clinical studies have demonstrated that a variety of currently used or investigational drugs, such as angiotensin-converting enzyme inhibitors, angiotensin AT1 receptors blockers, angiotensin-(1-7), antioxidants, beta-blockers, calcium channel blockers, endothelial NO synthase enhancers, phosphodiesterase 5 inhibitors, sphingosine-1-phosphate and statins, exert endothelial protective effects. Due to the difference in mechanisms of action, these drugs need to be used according to specific mechanisms underlying endothelial dysfunction of the disease. PMID:26635921

  3. Vascular endothelial dysfunction and pharmacological treatment.

    PubMed

    Su, Jin Bo

    2015-11-26

    The endothelium exerts multiple actions involving regulation of vascular permeability and tone, coagulation and fibrinolysis, inflammatory and immunological reactions and cell growth. Alterations of one or more such actions may cause vascular endothelial dysfunction. Different risk factors such as hypercholesterolemia, homocystinemia, hyperglycemia, hypertension, smoking, inflammation, and aging contribute to the development of endothelial dysfunction. Mechanisms underlying endothelial dysfunction are multiple, including impaired endothelium-derived vasodilators, enhanced endothelium-derived vasoconstrictors, over production of reactive oxygen species and reactive nitrogen species, activation of inflammatory and immune reactions, and imbalance of coagulation and fibrinolysis. Endothelial dysfunction occurs in many cardiovascular diseases, which involves different mechanisms, depending on specific risk factors affecting the disease. Among these mechanisms, a reduction in nitric oxide (NO) bioavailability plays a central role in the development of endothelial dysfunction because NO exerts diverse physiological actions, including vasodilation, anti-inflammation, antiplatelet, antiproliferation and antimigration. Experimental and clinical studies have demonstrated that a variety of currently used or investigational drugs, such as angiotensin-converting enzyme inhibitors, angiotensin AT1 receptors blockers, angiotensin-(1-7), antioxidants, beta-blockers, calcium channel blockers, endothelial NO synthase enhancers, phosphodiesterase 5 inhibitors, sphingosine-1-phosphate and statins, exert endothelial protective effects. Due to the difference in mechanisms of action, these drugs need to be used according to specific mechanisms underlying endothelial dysfunction of the disease. PMID:26635921

  4. Endothelial Dysfunction in Type 2 Diabetes Mellitus.

    PubMed

    Dhananjayan, R; Koundinya, K S Srivani; Malati, T; Kutala, Vijay Kumar

    2016-10-01

    Endothelial dysfunction is an imbalance in the production of vasodilator factors and when this balance is disrupted, it predisposes the vasculature towards pro-thrombotic and pro-atherogenic effects. This results in vasoconstriction, leukocyte adherence, platelet activation, mitogenesis, pro-oxidation, impaired coagulation and nitric oxide production, vascular inflammation, atherosclerosis and thrombosis. Endothelial dysfunction is focussed as it is a potential contributor to the pathogenesis of vascular disease in diabetes mellitus. Under physiological conditions, there is a balanced release of endothelial-derived relaxing and contracting factors, but this delicate balance is altered in diabetes mellitus and atherosclerosis, thereby contributing to further progression of vascular and end-organ damage. This review focuses on endothelial dysfunction in atherosclerosis, insulin resistance, metabolic syndrome, oxidative stress associated with diabetes mellitus, markers and genetics that are implicated in endothelial dysfunction.

  5. Endothelial cell micropatterning: Methods, effects, and applications

    PubMed Central

    Anderson, Deirdre E.J.; Hinds, Monica T.

    2012-01-01

    The effects of flow on endothelial cells have been widely examined for the ability of fluid shear stress to alter cell morphology and function; however, the effects of endothelial cell morphology without flow have only recently been observed. An increase in lithographic techniques in cell culture spurred a corresponding increase in research aiming to confine cell morphology. These studies lead to a better understanding of how morphology and cytoskeletal configuration affect the structure and function of the cells. This review examines endothelial cell micropatterning research by exploring both the many alternative methods used to alter endothelial cell morphology and the resulting changes in cellular shape and phenotype. Micropatterning induced changes in endothelial cell proliferation, apoptosis, cytoskeletal organization, mechanical properties, and cell functionality. Finally, the ways these cellular manipulation techniques have been applied to biomedical engineering research, including angiogenesis, cell migration, and tissue engineering, is discussed. PMID:21761242

  6. Endothelial Dysfunction in Type 2 Diabetes Mellitus.

    PubMed

    Dhananjayan, R; Koundinya, K S Srivani; Malati, T; Kutala, Vijay Kumar

    2016-10-01

    Endothelial dysfunction is an imbalance in the production of vasodilator factors and when this balance is disrupted, it predisposes the vasculature towards pro-thrombotic and pro-atherogenic effects. This results in vasoconstriction, leukocyte adherence, platelet activation, mitogenesis, pro-oxidation, impaired coagulation and nitric oxide production, vascular inflammation, atherosclerosis and thrombosis. Endothelial dysfunction is focussed as it is a potential contributor to the pathogenesis of vascular disease in diabetes mellitus. Under physiological conditions, there is a balanced release of endothelial-derived relaxing and contracting factors, but this delicate balance is altered in diabetes mellitus and atherosclerosis, thereby contributing to further progression of vascular and end-organ damage. This review focuses on endothelial dysfunction in atherosclerosis, insulin resistance, metabolic syndrome, oxidative stress associated with diabetes mellitus, markers and genetics that are implicated in endothelial dysfunction. PMID:27605734

  7. SNAP23 Regulates Endothelial Exocytosis of von Willebrand Factor

    PubMed Central

    Zhu, Qiuyu; Yamakuchi, Munekazu; Lowenstein, Charles J.

    2015-01-01

    Endothelial exocytosis regulates vascular thrombosis and inflammation. The trafficking and release of endothelial vesicles is mediated by SNARE (Soluble NSF Attachment protein REceptors) molecules, but the exact identity of endothelial SNAREs has been unclear. Three SNARE molecules form a ternary complex, including isoforms of the syntaxin (STX), vesicle-associated membrane protein (VAMP), and synaptosomal-associated protein (SNAP) families. We now identify SNAP23 as the predominant endothelial SNAP isoform that mediates endothelial exocytosis of von Willebrand Factor (VWF). SNAP23 was localized to the plasma membrane. Knockdown of SNAP23 decreased endothelial exocytosis, suggesting it is important for endothelial exocytosis. SNAP23 interacted with the endothelial exocytic machinery, and formed complexes with other known endothelial SNARE molecules. Taken together, these data suggest that SNAP23 is a key component of the endothelial SNARE machinery that mediates endothelial exocytosis. PMID:26266817

  8. [Endothelial function: role, assessment and limits].

    PubMed

    Puissant, C; Abraham, P; Durand, S; Humeau-Heurtier, A; Faure, S; Rousseau, P; Mahé, G

    2014-02-01

    For several years, detecting and preventing cardiovascular diseases have become a major issue. Different methods have been developed to evaluate endothelial function. Endothelial dysfunction is one of the first steps leading to atherosclerosis. This review presents an insight into endothelial function, the interests of its assessment and methods for studying endothelial function. To date, the vascular endothelium must be considered as a specific organ with its own functions that contribute to the homeostasis of the cardiovascular system. Endothelial dysfunction typically corresponds to a decrease of nitric oxide NO bioavailability. Biological or physico-chemical methods may be used to assess dysfunction. Biological methods allow measuring NO metabolites and pro-inflammatory and vasoconstrictor mediators released by the endothelium. The physico-chemical methods include intra-coronary injections, plethysmography, flow-mediated dilation (FMD), digital plethysmography and optical techniques using laser (laser Doppler single-point, laser Doppler imager, laser speckle contrast imaging) that can be coupled with provocation tests (iontophoresis, microdialysis, post-ischemic hyperemia, local heating). The principle of each technique and its use in clinical practice are discussed. Studying endothelial dysfunction is a particularly promising field because of new drugs being developed. Nevertheless, assessment methodology still needs further development to enable reliable, non-invasive, reproducible, and inexpensive ways to analyze endothelial dysfunction.

  9. Endothelial Heparan Sulfate in Angiogenesis

    PubMed Central

    Fuster, Mark M.; Wang, Lianchun

    2013-01-01

    Heparan sulfate (HS) is a linear polysaccharide composed of 50–200 glucosamine and uronic acid (glucuronic acid or iduronic acid) disaccharide repeats with epimerization and various sulfation modifications. HS is covalently attached to core proteins to form HS-proteoglycans. Most of the functions of HS-proteoglycans are mediated by their HS moieties. The biosynthesis of HS is initiated by chain polymerization and is followed by stepwise modification reactions, including sulfation and epimerization. These modifications generate ligand-binding sites that modulate cell functions and activities of proteinases and/or proteinase inhibitors. HS is abundantly expressed in developing and mature vasculature, and understanding its roles in vascular biology and related human diseases is an area of intense investigation. In this chapter, we summarize the significant recent advances in our understanding of the roles of HS in developmental and pathological angiogenesis with a major focus on studies using transgenic as well as gene knockout/knockdown models in mice and zebrafish. These studies have revealed that HS critically regulates angiogenesis by playing a proangiogenic role, and this regulatory function critically depends on HS fine structure. The latter is responsible for facilitating cell-surface binding of various proangiogenic growth factors that in turn mediate endothelial growth signaling. In cancer, mouse studies have revealed important roles for endothelial cell-surface HS as well as matrix-associated HS, wherein signaling by multiple growth factors as well as matrix storage of growth factors may be regulated by HS. We also discuss important mediators that may fine-tune such regulation, such as heparanase and sulfatases; and models wherein targeting HS (or core protein) biosynthesis may affect tumor growth and vascularization. Finally, the importance of targeting HS in other human diseases wherein angiogenesis may play pathophysiologic (or even therapeutic) roles

  10. Role of Lipotoxicity in Endothelial Dysfunction

    PubMed Central

    Kim, Jeong-a; Montagnani, Monica; Chandrasekran, Sruti; Quon, Michael J.

    2014-01-01

    SUMMARY Lipotoxicity, caused in large part by overnutrition, directly leads to endothelial dysfunction. Excess lipids in both the circulation and at the tissue level contribute to endothelial dysfunction that underlies much of the pathophysiology of both metabolic disease, including obesity and diabetes and their CV complications. Direct lipotoxic effects on other organs as well as secondary insults from endothelial dysfunction synergize to cause substantial morbidity and mortality. Lifestyle interventions, including reduced calorie intake, diet, and exercise as well as a variety of pharmacologic interventions targeting various mechanisms underlying lipotoxicity in vascular endothelium significantly modify metabolic and CV risk. PMID:22999242

  11. Circulating endothelial cells: a new biomarker of endothelial dysfunction in hematological diseases.

    PubMed

    Gendron, Nicolas; Smadja, David M

    2016-08-01

    The endothelium and its integrity are in the center of numerous cardiovascular, pulmonary and tumoral diseases. Several studies identified different circulating cellular sub-populations, which allow a noninvasive exploration of endothelial dysfunction. Furthermore, angiogenesis plays a major role in the biology of benign and malignant hematologic diseases. Among these biomarkers, circulating endothelial cells could be considered as a marker of endothelial injury and/or endothelial activation as well as vascular remodeling, whereas circulating endothelial progenitor cells would be only involved in the vascular regeneration. In the future, the quantification of circulating endothelial cells in many diseases could be a noninvasive biomarker used in diagnosis, prognostic and therapeutic follow-up of lung vasculopathy and/or residual disease of hematological malignancies.

  12. Asiaticoside Inhibits TNF-α-Induced Endothelial Hyperpermeability of Human Aortic Endothelial Cells.

    PubMed

    Fong, Lai Yen; Ng, Chin Theng; Zakaria, Zainul Amiruddin; Baharuldin, Mohamad Taufik Hidayat; Arifah, Abdul Kadir; Hakim, Muhammad Nazrul; Zuraini, Ahmad

    2015-10-01

    The increase in endothelial permeability often promotes edema formation in various pathological conditions. Tumor necrosis factor-alpha (TNF-α), a pro-atherogenic cytokine, impairs endothelial barrier function and causes endothelial dysfunction in early stage of atherosclerosis. Asiaticoside, one of the triterpenoids derived from Centella asiatica, is known to possess antiinflammatory activity. In order to examine the role of asiaticoside in preserving the endothelial barrier, we assessed its effects on endothelial hyperpermeability and disruption of actin filaments evoked by TNF-α in human aortic endothelial cells (HAEC). TNF-α caused an increase in endothelial permeability to fluorescein isothiocyanate (FITC)-dextran. Asiaticoside pretreatment significantly suppressed TNF-α-induced increased permeability. Asiaticoside also prevented TNF-α-induced actin redistribution by suppressing stress fiber formation. However, the increased F to G actin ratio stimulated by TNF-α was not changed by asiaticoside. Cytochalasin D, an actin depolymerizing agent, was used to correlate the anti-hyperpermeability effect of asiaticoside with actin cytoskeleton. Surprisingly, asiaticoside failed to prevent cytochalasin D-induced increased permeability. These results suggest that asiaticoside protects against the disruption of endothelial barrier and actin rearrangement triggered by TNF-α without a significant change in total actin pool. However, asiaticoside seems to work by other mechanisms to maintain the integrity of endothelial barrier rather than stabilizing the F-actin organization.

  13. The relationship between oxidised LDL, endothelial progenitor cells and coronary endothelial function in patients with CHD

    PubMed Central

    Watt, Jonathan; Kennedy, Simon; Ahmed, Nadeem; Hayhurst, James; McClure, John D; Berry, Colin; Wadsworth, Roger M; Oldroyd, Keith G

    2016-01-01

    Objective The balance between coronary endothelial dysfunction and repair is influenced by many protective and deleterious factors circulating in the blood. We studied the relationship between oxidised low-density lipoprotein (oxLDL), circulating endothelial progenitor cells (EPCs) and coronary endothelial function in patients with stable coronary heart disease (CHD). Methods 33 patients with stable CHD were studied. Plasma oxLDL was measured using ELISA, coronary endothelial function was assessed using intracoronary acetylcholine infusion and EPCs were quantified using flow cytometry for CD34+/KDR+ cells. Results Plasma oxLDL correlated positively with the number of EPCs in the blood (r=0.46, p=0.02). There was a positive correlation between the number of circulating EPCs and coronary endothelial function (r=0.42, p=0.04). There was no significant correlation between oxLDL and coronary endothelial function. Conclusions Plasma levels of oxLDL are associated with increased circulating EPCs in the blood of patients with CHD, which may reflect a host-repair response to endothelial injury. Patients with stable CHD had a high prevalence of coronary endothelial dysfunction, which was associated with lower numbers of circulating EPCs, suggesting a mechanistic link between endothelial dysfunction and the pathogenesis of atherosclerosis. PMID:26848395

  14. Soluble endoglin, hypercholesterolemia and endothelial dysfunction.

    PubMed

    Rathouska, Jana; Jezkova, Katerina; Nemeckova, Ivana; Nachtigal, Petr

    2015-12-01

    A soluble form of endoglin (sEng) is known to be an extracellular domain of the full-length membrane endoglin, which is elevated during various pathological conditions related to vascular endothelium. In the current review, we tried to summarize a possible role of soluble endoglin in cardiovascular pathologies, focusing on its relation to endothelial dysfunction and cholesterol levels. We discussed sEng as a proposed biomarker of cardiovascular disease progression, cardiovascular disease treatment and endothelial dysfunction. We also addressed a potential interaction of sEng with TGF-β/eNOS or BMP-9 signaling. We suggest soluble endoglin levels to be monitored, because they reflect the progression/treatment efficacy of cardiovascular diseases related to endothelial dysfunction and hypercholesterolemia. A possible role of soluble endoglin as an inducer of endothelial dysfunction however remains to be elucidated. PMID:26520890

  15. [Descemet's stripping automated endothelial keratoplasty (DSAEK)].

    PubMed

    Cursiefen, C; Kruse, F E

    2009-10-01

    Penetrating keratoplasty has been the gold standard for the surgical treatment of corneal endothelial pathologies, but tremendous progress has been made in recent years in improving the technology of posterior lamellar keratoplasty techniques such as Descemet's stripping automated endothelial keratoplasty (DSAEK). This progress is shown by a literature review using PubMed sources and our own clinical and experimental data. Posterior lamellar keratoplasty using a microkeratome is a reliable surgical technique for Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy. Visual rehabilitation is faster with lamellar compared with penetrating keratoplasty, but final visual acuity seems to be a bit reduced. Posterior lamellar keratoplasty techniques such as DSAEK may replace penetrating keratoplasty as the gold standard for treating a large proportion of corneal endothelial pathologies. PMID:19798505

  16. Mitochondria, endothelial cell function, and vascular diseases

    PubMed Central

    Tang, Xiaoqiang; Luo, Yu-Xuan; Chen, Hou-Zao; Liu, De-Pei

    2014-01-01

    Mitochondria are perhaps the most sophisticated and dynamic responsive sensing systems in eukaryotic cells. The role of mitochondria goes beyond their capacity to create molecular fuel and includes the generation of reactive oxygen species, the regulation of calcium, and the activation of cell death. In endothelial cells, mitochondria have a profound impact on cellular function under both healthy and diseased conditions. In this review, we summarize the basic functions of mitochondria in endothelial cells and discuss the roles of mitochondria in endothelial dysfunction and vascular diseases, including atherosclerosis, diabetic vascular dysfunction, pulmonary artery hypertension, and hypertension. Finally, the potential therapeutic strategies to improve mitochondrial function in endothelial cells and vascular diseases are also discussed, with a focus on mitochondrial-targeted antioxidants and calorie restriction. PMID:24834056

  17. Circulating and tissue resident endothelial progenitor cells.

    PubMed

    Basile, David P; Yoder, Mervin C

    2014-01-01

    Progenitor cells for the endothelial lineage have been widely investigated for more than a decade, but continue to be controversial since no unique identifying marker has yet been identified. This review will begin with a discussion of the basic tenets originally proposed for proof that a cell displays properties of an endothelial progenitor cell. We then provide an overview of the methods for putative endothelial progenitor cell derivation, expansion, and enumeration. This discussion includes consideration of cells that are present in the circulation as well as cells resident in the vascular endothelial intima. Finally, we provide some suggested changes in nomenclature that would greatly clarify and demystify the cellular elements involved in vascular repair.

  18. Genetics Home Reference: Fuchs endothelial dystrophy

    MedlinePlus

    ... a protein that is part of type VIII collagen. Type VIII collagen is largely found within the cornea, surrounding the endothelial cells. Specifically, type VIII collagen is a major component of a tissue at ...

  19. Endothelial glucocorticoid receptor suppresses atherogenesis- Brief Report

    PubMed Central

    Zhang, Xinbo; Rotllan, Noemi; Feng, Yan; Zhou, Han; Fernández-Hernando, Carlos; Yu, Jun; Sessa, William C.

    2015-01-01

    Objective The purpose of this study was to determine the role of the endothelial glucocorticoid receptor in the pathogenesis of atherosclerosis. Approach and Results Control mice and mice lacking the endothelial glucocorticoid receptor were bred onto an Apoe knockout background and subjected to high-fat diet feeding for 12 weeks. Assessment of body weight and total cholesterol and triglycerides before and after the diet revealed no differences between the two groups of mice. However, mice lacking the endothelial glucocorticoid receptor developed more severe atherosclerotic lesions in the aorta, brachiocephalic artery and aortic sinus as well as a heightened inflammatory milieu as evidence by increased macrophage recruitment in the lesions. Conclusions These data suggest the endothelial glucocorticoid receptor is important for tonic inhibition of inflammation and limitation of atherosclerosis progression in this model. PMID:25810297

  20. Endothelial progenitor cells in cardiovascular diseases.

    PubMed

    Lee, Poay Sian Sabrina; Poh, Kian Keong

    2014-07-26

    Endothelial dysfunction has been associated with the development of atherosclerosis and cardiovascular diseases. Adult endothelial progenitor cells (EPCs) are derived from hematopoietic stem cells and are capable of forming new blood vessels through a process of vasculogenesis. There are studies which report correlations between circulating EPCs and cardiovascular risk factors. There are also studies on how pharmacotherapies may influence levels of circulating EPCs. In this review, we discuss the potential role of endothelial progenitor cells as both diagnostic and prognostic biomarkers. In addition, we look at the interaction between cardiovascular pharmacotherapies and endothelial progenitor cells. We also discuss how EPCs can be used directly and indirectly as a therapeutic agent. Finally, we evaluate the challenges facing EPC research and how these may be overcome.

  1. Mesenchymal-endothelial-transition contributes to cardiac neovascularization

    PubMed Central

    Ubil, Eric; Duan, Jinzhu; Pillai, Indulekha C.L.; Rosa-Garrido, Manuel; Wu, Yong; Bargiacchi, Francesca; Lu, Yan; Stanbouly, Seta; Huang, Jie; Rojas, Mauricio; Vondriska, Thomas M.; Stefani, Enrico; Deb, Arjun

    2014-01-01

    Endothelial cells contribute to a subset of cardiac fibroblasts by undergoing endothelial-to-mesenchymal-transition, but whether cardiac fibroblasts can adopt an endothelial cell fate and directly contribute to neovascularization after cardiac injury is not known. Here, using genetic fate map techniques, we demonstrate that cardiac fibroblasts rapidly adopt an endothelial cell like phenotype after acute ischemic cardiac injury. Fibroblast derived endothelial cells exhibit anatomical and functional characteristics of native endothelial cells. We show that the transcription factor p53 regulates such a switch in cardiac fibroblast fate. Loss of p53 in cardiac fibroblasts severely decreases the formation of fibroblast derived endothelial cells, reduces post infarct vascular density and worsens cardiac function. Conversely, stimulation of the p53 pathway in cardiac fibroblasts augments mesenchymal to endothelial transition, enhances vascularity and improves cardiac function. These observations demonstrate that mesenchymal-to-endothelial-transition contributes to neovascularization of the injured heart and represents a potential therapeutic target for enhancing cardiac repair. PMID:25317562

  2. Vascular endothelial growth factor B, a novel growth factor for endothelial cells.

    PubMed Central

    Olofsson, B; Pajusola, K; Kaipainen, A; von Euler, G; Joukov, V; Saksela, O; Orpana, A; Pettersson, R F; Alitalo, K; Eriksson, U

    1996-01-01

    We have isolated and characterized a novel growth factor for endothelial cells, vascular endothelial growth factor B (VEGF-B), with structural similarities to vascular endothelial growth factor (VEGF) and placenta growth factor. VEGF-B was particularly abundant in heart and skeletal muscle and was coexpressed with VEGF in these and other tissues. VEGF-B formed cell-surface-associated disulfide-linked homodimers and heterodimerized with VEGF when coexpressed. Conditioned medium from transfected 293EBNA cells expressing VEGF-B stimulated DNA synthesis in endothelial cells. Our results suggest that VEGF-B has a role in angiogenesis and endothelial cell growth, particularly in muscle. Images Fig. 3 Fig. 4 Fig. 5 PMID:8637916

  3. Modulation of endothelial cell phenotype by physical activity: impact on obesity-related endothelial dysfunction.

    PubMed

    Bender, Shawn B; Laughlin, M Harold

    2015-07-01

    Increased levels of physical activity are associated with reduced cardiovascular disease (CVD) risk and mortality in obesity and diabetes. Available evidence suggests that local factors, including local hemodynamics, account for a significant portion of this CVD protection, and numerous studies have interrogated the therapeutic benefit of physical activity/exercise training in CVD. Less well established is whether basal differences in endothelial cell phenotype between/among vasculatures related to muscle recruitment patterns during activity may account for reports of nonuniform development of endothelial dysfunction in obesity. This is the focus of this review. We highlight recent work exploring the vulnerability of two distinct vasculatures with established differences in endothelial cell phenotype. Specifically, based largely on dramatic differences in underlying hemodynamics, arteries perfusing soleus muscle (slow-twitch muscle fibers) and those perfusing gastrocnemius muscle (fast-twitch muscle fibers) in the rat exhibit an exercise training-like versus an untrained endothelial cell phenotype, respectively. In the context of obesity, therefore, arteries to soleus muscle exhibit protection from endothelial dysfunction compared with vulnerable arteries to gastrocnemius muscle. This disparate vulnerability is consistent with numerous animal and human studies, demonstrating increased skeletal muscle blood flow heterogeneity in obesity coincident with reduced muscle function and exercise intolerance. Mechanistically, we highlight emerging areas of inquiry exploring novel aspects of hemodynamic-sensitive signaling in endothelial cells and the time course of physical activity-associated endothelial adaptations. Lastly, further exploration needs to consider the impact of endothelial heterogeneity on the development of endothelial dysfunction because endothelial dysfunction independently predicts CVD events.

  4. Endothelial progenitor cells in diabetic foot syndrome.

    PubMed

    Drela, Ewelina; Stankowska, Katarzyna; Kulwas, Arleta; Rość, Danuta

    2012-01-01

    In the late 20th century endothelial progenitor cells (EPCs) were discovered and identified as cells capable of differentiating into endothelial cells. Antigens characteristic of endothelial cells and hematopoietic cells are located on their surface. EPCs can proliferate, adhere, migrate and have the specific ability to form vascular structure, and they have a wide range of roles: They participate in maintaining hemostasis, and play an important part in the processes of vasculogenesis and angiogenesis. They are sources of angiogenic factors, especially vascular endothelial growth factor (VEGF). EPCs exist in bone marrow, from which they are recruited into circulation in response to specific stimuli. Tissue ischemia is thought to be the strongest inductor of EPC mobilization. Local ischemia accompanies many pathological states, including diabetic foot syndrome (DFS). Impaired angiogenesis--in which EPCs participate--is typical of DFS. An analysis of the available literature indicates that in diabetic patients the number of EPCs declines and their functioning is impaired. Endothelial progenitor cells are crucial to vasculogenesis and angiogenesis during ischemic neovascularization. The pathomechanisms underlying impaired angiogenesis in patients with DFS is complicated, but the discovery of EPCs has shed new light on the pathogenesis of many diseases, including diabetes foot syndrome.

  5. [Cytokines, endothelial dysfunction, and insulin resistance].

    PubMed

    de Carvalho, Maria Helena C; Colaço, André Luiz; Fortes, Zuleica Bruno

    2006-04-01

    Endothelial dysfunction is associated with several vascular conditions as atherosclerosis, hypertension, hyperlipidemia and diabetes mellitus. In all these conditions insulin resistance (IR) is present. Cytokines are low molecular weight proteins with several endocrine and metabolic functions that participate of inflammation and immune response. Several of these cytokines are independent risk factors for cerebrovascular and coronary artery disease. The major sources of cytokines (adipokines) are the visceral and subcutaneous adipose tissues. Thus, increased adipose tissue mass is associated with alteration in adipokine production as over expression of tumor necrosis factor alpha, interleukin 6, plasminogen activator inhibitor 1, and under expression of adiponectin in adipocite tissue. The pro-inflammatory status associated with these changes provides a potential link between IR and endothelial dysfunction, the early stage in the atherosclerotic process, in obese individuals, and type 2 diabetic patients. Reduction of adipose tissue mass through weight reduction in association with exercise reduces TNF-alpha, IL-6, and PAI-1, increases adiponectin, and is associated with improved insulin sensitivity and endothelial function. This review will focus on the evidence for regulation of endothelial function by insulin and the adypokines such as adyponectin, leptin, resistin, IL-6 and TNF-alpha. Interaction between insulin signaling and adypokines will be discussed, as well as the concept that aberrant adypokine secretion in IR and/or obesity impairs endothelial function and contributes further to reduce insulin sensitivity.

  6. PECAM-1: regulator of endothelial junctional integrity.

    PubMed

    Privratsky, Jamie R; Newman, Peter J

    2014-03-01

    PECAM-1 (also known as CD31) is a cellular adhesion and signaling receptor comprising six extracellular immunoglobulin (Ig)-like homology domains, a short transmembrane domain and a 118 amino acid cytoplasmic domain that becomes serine and tyrosine phosphorylated upon cellular activation. PECAM-1 expression is restricted to blood and vascular cells. In circulating platelets and leukocytes, PECAM-1 functions largely as an inhibitory receptor that, via regulated sequential phosphorylation of its cytoplasmic domain, limits cellular activation responses. PECAM-1 is also highly expressed at endothelial cell intercellular junctions, where it functions as a mechanosensor, as a regulator of leukocyte trafficking and in the maintenance of endothelial cell junctional integrity. In this review, we will describe (1) the functional domains of PECAM-1 and how they contribute to its barrier-enhancing properties, (2) how the physical properties of PECAM-1 influence its subcellular localization and its ability to influence endothelial cell barrier function, (3) various stimuli that initiate PECAM-1 signaling and/or function at the endothelial junction and (4) cross-talk of PECAM-1 with other junctional molecules, which can influence endothelial cell function. PMID:24435645

  7. Endothelial Cell Response to Fusobacterium nucleatum.

    PubMed

    Mendes, Reila Tainá; Nguyen, Daniel; Stephens, Danielle; Pamuk, Ferda; Fernandes, Daniel; Van Dyke, Thomas E; Kantarci, Alpdogan

    2016-07-01

    Vascular response is an essential aspect of an effective immune response to periodontal disease pathogens, as new blood vessel formation contributes to wound healing and inflammation. Gaining a greater understanding of the factors that affect vascular response may then contribute to future breakthroughs in dental medicine. In this study, we have characterized the endothelial cell response to the common bacterium Fusobacterium nucleatum, an important bridging species that facilitates the activity of late colonizers of the dental biofilm. Endothelial cells were infected with Fusobacterium nucleatum (strain 25586) for periods of 4, 12, 24, or 48 h. Cell proliferation and tube formation were analyzed, and expression of adhesion molecules (CD31 and CD34) and vascular endothelial growth factor (VEGF) receptors 1 and 2 was measured by fluorescence-activated cell sorter (FACS) analysis. Data indicate that F. nucleatum impaired endothelial cell proliferation and tube formation. The findings suggest that the modified endothelial cell response acts as a mechanism promoting the pathogenic progression of periodontal diseases and may potentially suggest the involvement of periodontopathogens in systemic diseases associated with periodontal inflammation.

  8. KRIT1 Protein Depletion Modifies Endothelial Cell Behavior via Increased Vascular Endothelial Growth Factor (VEGF) Signaling*

    PubMed Central

    DiStefano, Peter V.; Kuebel, Julia M.; Sarelius, Ingrid H.; Glading, Angela J.

    2014-01-01

    Disruption of endothelial cell-cell contact is a key event in many cardiovascular diseases and a characteristic of pathologically activated vascular endothelium. The CCM (cerebral cavernous malformation) family of proteins (KRIT1 (Krev-interaction trapped 1), PDCD10, and CCM2) are critical regulators of endothelial cell-cell contact and vascular homeostasis. Here we show novel regulation of vascular endothelial growth factor (VEGF) signaling in KRIT1-depleted endothelial cells. Loss of KRIT1 and PDCD10, but not CCM2, increases nuclear β-catenin signaling and up-regulates VEGF-A protein expression. In KRIT1-depleted cells, increased VEGF-A levels led to increased VEGF receptor 2 (VEGFR2) activation and subsequent alteration of cytoskeletal organization, migration, and barrier function and to in vivo endothelial permeability in KRIT1-deficient animals. VEGFR2 activation also increases β-catenin phosphorylation but is only partially responsible for KRIT1 depletion-dependent disruption of cell-cell contacts. Thus, VEGF signaling contributes to modifying endothelial function in KRIT1-deficient cells and microvessel permeability in Krit1+/− mice; however, VEGF signaling is likely not the only contributor to disrupted endothelial cell-cell contacts in the absence of KRIT1. PMID:25320085

  9. Development of Endothelial-Specific Single Inducible Lentiviral Vectors for Genetic Engineering of Endothelial Progenitor Cells.

    PubMed

    Yang, Guanghua; Kramer, M Gabriela; Fernandez-Ruiz, Veronica; Kawa, Milosz P; Huang, Xin; Liu, Zhongmin; Prieto, Jesus; Qian, Cheng

    2015-11-27

    Endothelial progenitor cells (EPC) are able to migrate to tumor vasculature. These cells, if genetically modified, can be used as vehicles to deliver toxic material to, or express anticancer proteins in tumor. To test this hypothesis, we developed several single, endothelial-specific, and doxycycline-inducible self-inactivating (SIN) lentiviral vectors. Two distinct expression cassettes were inserted into a SIN-vector: one controlled by an endothelial lineage-specific, murine vascular endothelial cadherin (mVEcad) promoter for the expression of a transactivator, rtTA2S-M2; and the other driven by an inducible promoter, TREalb, for a firefly luciferase reporter gene. We compared the expression levels of luciferase in different vector constructs, containing either the same or opposite orientation with respect to the vector sequence. The results showed that the vector with these two expression cassettes placed in opposite directions was optimal, characterized by a robust induction of the transgene expression (17.7- to 73-fold) in the presence of doxycycline in several endothelial cell lines, but without leakiness when uninduced. In conclusion, an endothelial lineage-specific single inducible SIN lentiviral vector has been developed. Such a lentiviral vector can be used to endow endothelial progenitor cells with anti-tumor properties.

  10. 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.

  11. Glassy Dynamics, Cell Mechanics and Endothelial Permeability

    PubMed Central

    Hardin, Corey; Rajendran, Kavitha; Manomohan, Greeshma; Tambe, Dhananjay T.; Butler, James P.; Fredberg, Jeffrey J.; Martinelli, Roberta; Carman, Christopher V.; Krishnan, Ramaswamy

    2013-01-01

    A key feature of all inflammatory processes is disruption of the vascular endothelial barrier. Such disruption is initiated in part through active contraction of the cytoskeleton of the endothelial cell (EC). Because contractile forces are propagated from cell to cell across a great many cell-cell junctions, this contractile process is strongly cooperative and highly nonlocal. We show here that the characteristic length scale of propagation is modulated by agonists and antagonists that impact permeability of the endothelial barrier. In the presence of agonists including thrombin, histamine, and H202, force correlation length increases, whereas in the presence of antagonists including sphingosine-1-phosphate, hepatocyte growth factor, and the rho kinase inhibitor, Y27632, force correlation length decreases. Intercellular force chains and force clusters are also evident, both of which are reminiscent of soft glassy materials approaching a glass transition. PMID:23638866

  12. Establishment of outgrowth endothelial cells from peripheral blood.

    PubMed

    Martin-Ramirez, Javier; Hofman, Menno; van den Biggelaar, Maartje; Hebbel, Robert P; Voorberg, Jan

    2012-09-01

    Blood outgrowth endothelial cells (BOECs) are important tools when investigating diagnostic and therapeutic approaches for vascular disease. In this protocol, mononuclear cells are isolated from peripheral blood and plated on type I collagen at ∼135,000 cells per cm(2) in endothelial cell differentiation medium. On average, 0.34 colonies of endothelial cells per milliliter of blood can be obtained. Colonies of endothelial cells become visible after 14-28 d. Upon confluence, these rapidly expanding colonies can be passaged and have been shown to propagate up to 10(18)-fold. Isolated BOECs are phenotypically similar to vascular endothelial cells, as revealed by their cobblestone morphology, the presence of endothelial cell-specific Weibel-Palade bodies and the expression of endothelial cell markers such as VE-cadherin. The protocol presented here also provides a particularly useful tool for the ex vivo assessment of endothelial cell function from patients with different vascular abnormalities. PMID:22918388

  13. Isolation and culture of pulmonary endothelial cells.

    PubMed

    Ryan, U S

    1984-06-01

    Methods for isolation, identification and culture of pulmonary endothelial cells are now routine. In the past, methods of isolation have used proteolytic enzymes to detach cells; thereafter, traditional methods for cell passaging have used trypsin/EDTA mixtures. Cells isolated and passaged using proteolytic enzymes have been useful in establishing the field and in verifying certain endothelial properties. However, there is a growing awareness of the role of endothelial cells in processing vasoactive substances, in responding to hormones and other agonists and in cell-cell interactions with other cell types of the vascular wall, with blood cells and with cellular products. Consequently, a new requirement has arisen for cells in vitro that maintain the differentiated properties of their counterparts in vivo. The deleterious effects of trypsin and other proteolytic enzymes commonly used in cell culture on surface structures of endothelial cells such as enzymes, receptors and junctional proteins, as well as on extracellular layers such as the glycocalyx or "endothelial fuzz," have led to the development of methods that avoid use of proteolytic enzymes at both the isolation step and during subsequent subculture. This chapter describes traditional methods for isolating pulmonary endothelial cells but emphasizes newer approaches using mechanical harvest and scale-up using microcarriers. The new methods allow maintenance of long-term, large-scale cultures of cells that retain the full complement of surface properties and that maintain the cobblestone monolayer morphology and differentiated functional properties. Methods for identification of isolated cells are therefore also considered as methods for validation of cultures during their in vitro lifespan. PMID:6090112

  14. 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.

  15. Enhancing endothelial progenitor cell for clinical use

    PubMed Central

    Ye, Lei; Poh, Kian-Keong

    2015-01-01

    Circulating endothelial progenitor cells (EPCs) have been demonstrated to correlate negatively with vascular endothelial dysfunction and cardiovascular risk factors. However, translation of basic research into the clinical practice has been limited by the lack of unambiguous and consistent definitions of EPCs and reduced EPC cell number and function in subjects requiring them for clinical use. This article critically reviews the definition of EPCs based on commonly used protocols, their value as a biomarker of cardiovascular risk factor in subjects with cardiovascular disease, and strategies to enhance EPCs for treatment of ischemic diseases. PMID:26240678

  16. Enhancing endothelial progenitor cell for clinical use.

    PubMed

    Ye, Lei; Poh, Kian-Keong

    2015-07-26

    Circulating endothelial progenitor cells (EPCs) have been demonstrated to correlate negatively with vascular endothelial dysfunction and cardiovascular risk factors. However, translation of basic research into the clinical practice has been limited by the lack of unambiguous and consistent definitions of EPCs and reduced EPC cell number and function in subjects requiring them for clinical use. This article critically reviews the definition of EPCs based on commonly used protocols, their value as a biomarker of cardiovascular risk factor in subjects with cardiovascular disease, and strategies to enhance EPCs for treatment of ischemic diseases.

  17. Endothelial progenitor cells--an evolving story.

    PubMed

    Pearson, Jeremy D

    2010-05-01

    The first description of endothelial progenitor cells (EPC) in 1997 led rapidly to substantial changes in our understanding of angiogenesis, and within 5 years to the first clinical studies in humans using bone marrow derived EPC to enhance coronary neovascularisation and cardiac function after myocardial ischemia. However, to improve the success of this therapy a clearer understanding of the biology of EPC is needed. This article summarises recent data indicating that most EPC are not, in fact, endothelial progenitors but can be better described as angiogenic monocytes, and explores the implications this has for their future therapeutic use.

  18. Rapamycin inhibits re-endothelialization after percutaneous coronary intervention by impeding the proliferation and migration of endothelial cells and inducing apoptosis of endothelial progenitor cells.

    PubMed

    Liu, Hai-Tao; Li, Fei; Wang, Wen-Yong; Li, Xiao-Jing; Liu, Yi-Meng; Wang, Rui-An; Guo, Wen-Yi; Wang, Hai-Chang

    2010-01-01

    Endothelial-cell function is important in the healing of damaged endothelium after percutaneous coronary artery damage. In 3 different animal models, we sought to determine whether rapamycin (sirolimus) affects the proliferation and migration of endothelial cells and endothelial progenitor cells. First, after we implanted stents in dogs, we found that re-endothelialization was impeded more by drug-eluting stents than by bare-metal stents, 30 days after percutaneous coronary intervention. Second, in vitro in rats, we found that 1-100 ng/mL of rapamycin time- and dose-dependently inhibited proliferation over 72 hr (with effects evident as early as 24 hr) and also dose-dependently induced endothelial progenitor-cell apoptosis. Finally, in vivo in rats, we observed that vascular endothelial growth factor expression was decreased after 5 days of rapamycin treatment. We conclude that rapamycin impedes re-endothelialization after drug-eluting stent implantation by inhibiting the proliferation and migration of coronary endothelial cells, inducing endothelial progenitor-cell apoptosis, and decreasing vascular endothelial growth factor expression in the circulation. PMID:20401293

  19. Platelet endothelial cell adhesion molecule-1 and mechanotransduction in vascular endothelial cells.

    PubMed

    Fujiwara, K

    2006-04-01

    Endothelial cells are known to respond to mechanical forces such as fluid shear stress and cyclic stretch, but elucidating the mechanism for mechanosensing has been difficult. Experimental data indicate that there are probably several sensing mechanisms. We have recently proposed a novel mechanoresponse mechanism that involves platelet endothelial cell adhesion molecule-1 (PECAM-1). When endothelial cells are stimulated by fluid shear stress, PECAM-1 is tyrosine phosphorylated and activates the extracellular signal-regulated kinase 1 and 2 (ERK1/2) signalling cascade. The same signalling events occurred when we applied pulling force directly on PECAM-1 on the endothelial cell surface using magnetic beads coated with antibodies against the external domain of PECAM-1. These results appear to indicate that PECAM-1 is a mechanotransduction molecule. To our knowledge, this is the first mammalian molecule that is shown to respond to mechanical force directly exerted to it. PMID:16594905

  20. Adipose-derived stem cells (ASCs) as a source of endothelial cells in the reconstruction of endothelialized skin equivalents.

    PubMed

    Auxenfans, C; Lequeux, C; Perrusel, E; Mojallal, A; Kinikoglu, B; Damour, O

    2012-07-01

    Tissue-engineered autologous skin is a potential alternative to autograft for burn coverage, but produces poor clinical responses such as unsatisfactory graft intake due to insufficient vascularization. Endothelialized skin equivalents comprising human umbilical vein endothelial cells (HUVECs) survive significantly longer due to inosculation with the capillaries of the host, but these cells are allogeneic by definition. The aim of this study was to reconstruct an autologous endothelialized skin equivalent by incorporating progenitor or pre-differentiated endothelial cells derived from adipose tissue, easily accessible source for autologous transplantation. Human adipose tissue-derived stem cells were isolated from lipoaspirates and amplified to obtain endothelial progenitor cells, which were subsequently differentiated into endothelial cells. These cells were then seeded along with human fibroblasts into a porous collagen-glycosaminoglycan-chitosan scaffold to obtain an endothelialized dermal equivalent. Then, human keratinocytes give rise to a endothelialized skin equivalent. Immunohistochemistry and transmission electron microscopy results demonstrate the presence of capillary-like tubular structures in skin equivalents comprising pre-differentiated endothelial cells, but not endothelial progenitor cells. The former expressed both EN4 and von Willebrand factor, and Weibel-Palade bodies were detected in their cytoplasm. This study demonstrates that adipose tissue is an excellent source of autologous endothelial cells to reconstruct endothelialized tissue equivalents, and that pre-differentiation of stem cells is necessary to obtain vasculature in such models. PMID:21755603

  1. 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

  2. Protective effects of vascular endothelial growth factor in cultured brain endothelial cells against hypoglycemia.

    PubMed

    Zhao, Fei; Deng, Jiangshan; Yu, Xiaoyan; Li, Dawei; Shi, Hong; Zhao, Yuwu

    2015-08-01

    Hypoglycemia is a common and serious problem among patients with type 1 diabetes receiving treatment with insulin. Clinical studies have demonstrated that hypoglycemic edema is involved in the initiation of hypoglycemic brain damage. However, the mechanisms of this edema are poorly understood. Vascular endothelial growth factor (VEGF), a potent regulator of blood vessel function, has been observed an important candidate hormone induced by hypoglycemia to protect neurons by restoring plasma glucose. Whether VEGF has a protective effect against hypoglycemia-induced damage in brain endothelial cells is still unknown. To investigate the effects of hypoglycemia on cerebral microvascular endothelial cells and assess the protective effect of exogenous VEGF on endothelial cells during hypoglycemia, confluent monolayers of the brain endothelial cell line bEnd.3 were treated with normal (5.5 mM glucose), hypoglycemic (0, 0.5, 1 mM glucose) medium or hypoglycemic medium in the presence of VEGF. The results clearly showed that hypoglycemia significantly downregulated the expression of claudin-5 in bEnd.3 cells, without affecting ZO-1 and occludin expression and distribution. Besides, transendothelial permeability significantly increased under hypoglycemic conditions compared to that under control conditions. Moreover, the hypoglycemic medium in presence of VEGF decreased endothelial permeability via the inhibition of claudin-5 degradation and improved hypoglycemia-induced cell toxicity. Furthermore, Glucose transporter-1 (Glut-1) and apoptosis regulator Bcl-2 expression were significantly upregulated. Taken together, hypoglycemia can significantly increase paraendocellular permeability by downregulating claudin-5 expression. We further showed that VEGF protected brain endothelial cells against hypoglycemia by enhancing glucose passage, reducing endothelial cell death, and ameliorating paraendocellular permeability.

  3. Genetic Variation in the Platelet Endothelial Aggregation Receptor 1 Gene Results in Endothelial Dysfunction.

    PubMed

    Fisch, Adam S; Yerges-Armstrong, Laura M; Backman, Joshua D; Wang, Hong; Donnelly, Patrick; Ryan, Kathleen A; Parihar, Ankita; Pavlovich, Mary A; Mitchell, Braxton D; O'Connell, Jeffrey R; Herzog, William; Harman, Christopher R; Wren, Jonathan D; Lewis, Joshua P

    2015-01-01

    Platelet Endothelial Aggregation Receptor 1 (PEAR1) is a newly identified membrane protein reported to be involved in multiple vascular and thrombotic processes. While most studies to date have focused on the effects of this receptor in platelets, PEAR1 is located in multiple tissues including the endothelium, where it is most highly expressed. Our first objective was to evaluate the role of PEAR1 in endothelial function by examining flow-mediated dilation of the brachial artery in 641 participants from the Heredity and Phenotype Intervention Heart Study. Our second objective was to further define the impact of PEAR1 on cardiovascular disease computationally through meta-analysis of 75,000 microarrays, yielding insights regarding PEAR1 function, and predictions of phenotypes and diseases affected by PEAR1 dysregulation. Based on the results of this meta-analysis we examined whether genetic variation in PEAR1 influences endothelial function using an ex vivo assay of endothelial cell migration. We observed a significant association between rs12041331 and flow-mediated dilation in participants of the Heredity and Phenotype Intervention Heart Study (P = 0.02). Meta-analysis results revealed that PEAR1 expression is highly correlated with several genes (e.g. ANG2, ACVRL1, ENG) and phenotypes (e.g. endothelial cell migration, angiogenesis) that are integral to endothelial function. Functional validation of these results revealed that PEAR1 rs12041331 is significantly associated with endothelial migration (P = 0.04). Our results suggest for the first time that genetic variation of PEAR1 is a significant determinant of endothelial function through pathways implicated in cardiovascular disease. PMID:26406321

  4. Brain endothelial dysfunction in cerebral adrenoleukodystrophy.

    PubMed

    Musolino, Patricia L; Gong, Yi; Snyder, Juliet M T; Jimenez, Sandra; Lok, Josephine; Lo, Eng H; Moser, Ann B; Grabowski, Eric F; Frosch, Matthew P; Eichler, Florian S

    2015-11-01

    See Aubourg (doi:10.1093/awv271) for a scientific commentary on this article.X-linked adrenoleukodystrophy is caused by mutations in the ABCD1 gene leading to accumulation of very long chain fatty acids. Its most severe neurological manifestation is cerebral adrenoleukodystrophy. Here we demonstrate that progressive inflammatory demyelination in cerebral adrenoleukodystrophy coincides with blood-brain barrier dysfunction, increased MMP9 expression, and changes in endothelial tight junction proteins as well as adhesion molecules. ABCD1, but not its closest homologue ABCD2, is highly expressed in human brain microvascular endothelial cells, far exceeding its expression in the systemic vasculature. Silencing of ABCD1 in human brain microvascular endothelial cells causes accumulation of very long chain fatty acids, but much later than the immediate upregulation of adhesion molecules and decrease in tight junction proteins. This results in greater adhesion and transmigration of monocytes across the endothelium. PCR-array screening of human brain microvascular endothelial cells after ABCD1 silencing revealed downregulation of both mRNA and protein levels of the transcription factor c-MYC (encoded by MYC). Interestingly, MYC silencing mimicked the effects of ABCD1 silencing on CLDN5 and ICAM1 without decreasing the levels of ABCD1 protein itself. Together, these data demonstrate that ABCD1 deficiency induces significant alterations in brain endothelium via c-MYC and may thereby contribute to the increased trafficking of leucocytes across the blood-brain barrier as seen in cerebral adrenouleukodystrophy. PMID:26377633

  5. Endothelial FAK is required for tumour angiogenesis

    PubMed Central

    Tavora, Bernardo; Batista, Silvia; Reynolds, Louise E; Jadeja, Shalini; Robinson, Stephen; Kostourou, Vassiliki; Hart, Ian; Fruttiger, Marcus; Parsons, Maddy; Hodivala-Dilke, Kairbaan M

    2010-01-01

    Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that plays a fundamental role in integrin and growth factor mediated signalling and is an important player in cell migration and proliferation, processes vital for angiogenesis. However, the role of FAK in adult pathological angiogenesis is unknown. We have generated endothelial-specific tamoxifen-inducible FAK knockout mice by crossing FAK-floxed (FAKfl/fl) mice with the platelet derived growth factor b (Pdgfb)-iCreER mice. Tamoxifen-treatment of Pdgfb-iCreER;FAKfl/fl mice results in FAK deletion in adult endothelial cells (ECs) without any adverse effects. Importantly however, endothelial FAK-deletion in adult mice inhibited tumour growth and reduced tumour angiogenesis. Furthermore, in in vivo angiogenic assays FAK deletion impairs vascular endothelial growth factor (VEGF)-induced neovascularization. In addition, in vitro deletion of FAK in ECs resulted in reduced VEGF-stimulated Akt phosphorylation and correlating reduced cellular proliferation as well as increased cell death. Our data suggest that FAK is required for adult pathological angiogenesis and validates FAK as a possible target for anti-angiogenic therapies. PMID:21154724

  6. Endothelial progenitor cells in hematologic malignancies

    PubMed Central

    Saulle, Ernestina; Castelli, Germana; Pelosi, Elvira

    2016-01-01

    Studies carried out in the last years have improved the understanding of the cellular and molecular mechanisms controlling angiogenesis during adult life in normal and pathological conditions. Some of these studies have led to the identification of some progenitor cells that sustain angiogenesis through indirect, paracrine mechanisms (hematopoietic angiogenic cells) and through direct mechanisms, i.e., through their capacity to generate a progeny of phenotypically and functionally competent endothelial cells [endothelial colony forming cells (ECFCs)]. The contribution of these progenitors to angiogenetic processes under physiological and pathological conditions is intensively investigated. Angiogenetic mechanisms are stimulated in various hematological malignancies, including chronic myeloid leukemia (CML), acute myeloid leukemia (AML), myelodysplastic syndromes and multiple myeloma, resulting in an increased angiogenesis that contributes to disease progression. In some of these conditions there is preliminary evidence that some endothelial cells could derive from the malignant clone, thus leading to the speculation that the leukemic cell derives from the malignant transformation of a hemangioblastic progenitor, i.e., of a cell capable of differentiation to the hematopoietic and to the endothelial cell lineages. Our understanding of the mechanisms underlying increased angiogenesis in these malignancies not only contributed to a better knowledge of the mechanisms responsible for tumor progression, but also offered the way for the discovery of new therapeutic targets. PMID:27583252

  7. Lymphatic endothelial lineage assemblage during corneal lymphangiogenesis

    PubMed Central

    Connor, Alicia L.; Kelley, Philip M.; Tempero, Richard M.

    2015-01-01

    Post natal inflammatory lymphangiogenesis presumably requires precise regulatory processes to properly assemble proliferating lymphatic endothelial cells (LECs). The specific mechanisms that regulate the assembly of LECs during new lymphatic vessel synthesis are unclear. Dynamic endothelial shuffling and rearrangement has been proposed as a mechanism of blood vessel growth. We developed genetic lineage tracing strategies using an inductive transgenic technology to track the fate of entire tandem dimer tomato positive (tdT) lymphatic vessels or small, in some cases clonal, populations of LECs. We coupled this platform with a suture induced mouse model of corneal lymphangiogenesis and used different analytic microscopy techniques including serial live imaging to study the spatial properties of proliferating tdT+ LEC progenies. LEC precursors and their progeny expanded from the corneal limbal lymphatic vessel and were assembled contiguously to comprise a subunit within a new lymphatic vessel. VE-cadherin blockade induced morphologic abnormalities in newly synthesized lymphatic vessels, but did not disrupt the tdT+ lymphatic endothelial lineage assembly. Analysis of this static and dynamic data based largely on direct in vivo observations supports a model of lymphatic endothelial lineage assemblage during corneal inflammatory lymphangiogenesis. PMID:26658452

  8. Endothelial progenitor cells in hematologic malignancies.

    PubMed

    Testa, Ugo; Saulle, Ernestina; Castelli, Germana; Pelosi, Elvira

    2016-01-01

    Studies carried out in the last years have improved the understanding of the cellular and molecular mechanisms controlling angiogenesis during adult life in normal and pathological conditions. Some of these studies have led to the identification of some progenitor cells that sustain angiogenesis through indirect, paracrine mechanisms (hematopoietic angiogenic cells) and through direct mechanisms, i.e., through their capacity to generate a progeny of phenotypically and functionally competent endothelial cells [endothelial colony forming cells (ECFCs)]. The contribution of these progenitors to angiogenetic processes under physiological and pathological conditions is intensively investigated. Angiogenetic mechanisms are stimulated in various hematological malignancies, including chronic myeloid leukemia (CML), acute myeloid leukemia (AML), myelodysplastic syndromes and multiple myeloma, resulting in an increased angiogenesis that contributes to disease progression. In some of these conditions there is preliminary evidence that some endothelial cells could derive from the malignant clone, thus leading to the speculation that the leukemic cell derives from the malignant transformation of a hemangioblastic progenitor, i.e., of a cell capable of differentiation to the hematopoietic and to the endothelial cell lineages. Our understanding of the mechanisms underlying increased angiogenesis in these malignancies not only contributed to a better knowledge of the mechanisms responsible for tumor progression, but also offered the way for the discovery of new therapeutic targets. PMID:27583252

  9. Chronic Inflammatory Diseases and Endothelial Dysfunction

    PubMed Central

    Castellon, Xavier; Bogdanova, Vera

    2016-01-01

    Chronic inflammatory diseases are associated with increases in cardiovascular diseases (CVD) and subclinical atherosclerosis as well as early-stage endothelial dysfunction screening using the FMD method (Flow Mediated Dilation). This phenomenon, referred to as accelerated pathological remodeling of arterial wall, could be attributed to traditional risk factors associated with atherosclerosis. Several new non-invasive techniques have been used to study arterial wall’s structural and functional alterations. These techniques (based of Radio Frequency, RF) allow for an assessment of artery age through calculations of intima-media thickness (RF- QIMT), pulse wave rate (RF- QAS) and endothelial dysfunction degree (FMD). The inflammatory and autoimmune diseases should now be considered as new cardiovascular risk factors, result of the major consequences of oxidative stress and RAS (Renin Angiotensin System) imbalance associated with the deleterious effect of known risk factors that lead to the alteration of the arterial wall. Inflammation plays a key role in all stages of the formation of vascular lesions maintained and exacerbated by the risk factors. The consequence of chronic inflammation is endothelial dysfunction that sets in and we can define it as an integrated marker of the damage to arterial walls by classic risk factors. The atherosclerosis, which develops among these patients, is the main cause for cardiovascular morbi-mortality and uncontrolled chronic biological inflammation, which quickly favors endothelial dysfunction. These inflammatory and autoimmune diseases should now be considered as new cardiovascular risk factors. PMID:26815098

  10. Flow over glycocalyx covered endothelial cells.

    NASA Astrophysics Data System (ADS)

    Waters, Sarah L.; Liu, Shu Q.; Grotberg, James B.

    1997-11-01

    Blood vessels are lined with a monolayer of endothelial cells that interact with the blood flow. Two structural features of the endothelial membrane may influence the fluid dynamics over the endothelium: 1) the endothelial membrane bumpiness; and 2) the porous glycocalyx layer covering the cell surface. The bumpiness of the endothelium may induce regions of recirculation, and the glycocalyx may effect the flow pattern at the cell surface. An analytical study is presented for pressure driven blood flow in the microcirculation. The vessel is modeled as a rigid, impermeable, symmetric two--dimensional channel, which has sinusoidally wavy walls. The vessel has two regions: 1) the glycocalyx layer which is modeled as a uniformly thick poroelastic deformable wall layer using biphasic mixture theory; and 2) the free lumen where the Navier--Stokes equations of motion apply. Analytical results are obtained by making the long wavelength approximation. The model predicts the fluid flow and hence the shear stress exerted by the flow on the individual endothelial cells and at the glycocalyx--lumen interface. Implications of the results for biological events such as molecular transport and signal transduction are considered.

  11. Brain endothelial dysfunction in cerebral adrenoleukodystrophy.

    PubMed

    Musolino, Patricia L; Gong, Yi; Snyder, Juliet M T; Jimenez, Sandra; Lok, Josephine; Lo, Eng H; Moser, Ann B; Grabowski, Eric F; Frosch, Matthew P; Eichler, Florian S

    2015-11-01

    See Aubourg (doi:10.1093/awv271) for a scientific commentary on this article.X-linked adrenoleukodystrophy is caused by mutations in the ABCD1 gene leading to accumulation of very long chain fatty acids. Its most severe neurological manifestation is cerebral adrenoleukodystrophy. Here we demonstrate that progressive inflammatory demyelination in cerebral adrenoleukodystrophy coincides with blood-brain barrier dysfunction, increased MMP9 expression, and changes in endothelial tight junction proteins as well as adhesion molecules. ABCD1, but not its closest homologue ABCD2, is highly expressed in human brain microvascular endothelial cells, far exceeding its expression in the systemic vasculature. Silencing of ABCD1 in human brain microvascular endothelial cells causes accumulation of very long chain fatty acids, but much later than the immediate upregulation of adhesion molecules and decrease in tight junction proteins. This results in greater adhesion and transmigration of monocytes across the endothelium. PCR-array screening of human brain microvascular endothelial cells after ABCD1 silencing revealed downregulation of both mRNA and protein levels of the transcription factor c-MYC (encoded by MYC). Interestingly, MYC silencing mimicked the effects of ABCD1 silencing on CLDN5 and ICAM1 without decreasing the levels of ABCD1 protein itself. Together, these data demonstrate that ABCD1 deficiency induces significant alterations in brain endothelium via c-MYC and may thereby contribute to the increased trafficking of leucocytes across the blood-brain barrier as seen in cerebral adrenouleukodystrophy.

  12. Endothelial FAK is required for tumour angiogenesis.

    PubMed

    Tavora, Bernardo; Batista, Silvia; Reynolds, Louise E; Jadeja, Shalini; Robinson, Stephen; Kostourou, Vassiliki; Hart, Ian; Fruttiger, Marcus; Parsons, Maddy; Hodivala-Dilke, Kairbaan M

    2010-12-01

    Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that plays a fundamental role in integrin and growth factor mediated signalling and is an important player in cell migration and proliferation, processes vital for angiogenesis. However, the role of FAK in adult pathological angiogenesis is unknown. We have generated endothelial-specific tamoxifen-inducible FAK knockout mice by crossing FAK-floxed (FAKfl/fl) mice with the platelet derived growth factor b (Pdgfb)-iCreER mice. Tamoxifen-treatment of Pdgfb-iCreER;FAKfl/fl mice results in FAK deletion in adult endothelial cells (ECs) without any adverse effects. Importantly however, endothelial FAK-deletion in adult mice inhibited tumour growth and reduced tumour angiogenesis. Furthermore, in in vivo angiogenic assays FAK deletion impairs vascular endothelial growth factor (VEGF)-induced neovascularization. In addition, in vitro deletion of FAK in ECs resulted in reduced VEGF-stimulated Akt phosphorylation and correlating reduced cellular proliferation as well as increased cell death. Our data suggest that FAK is required for adult pathological angiogenesis and validates FAK as a possible target for anti-angiogenic therapies.

  13. Circulating endothelial cells in cardiovascular disease.

    PubMed

    Boos, Christopher J; Lip, Gregory Y H; Blann, Andrew D

    2006-10-17

    Quantification of circulating endothelial cells (CECs) in peripheral blood is developing as a novel and reproducible method of assessing endothelial damage/dysfunction. The CECs are thought to be mature cells that have detached from the intimal monolayer in response to endothelial injury and are a different cell population to endothelial progenitor cells (EPCs). The EPCs are nonleukocytes derived from the bone marrow that are believed to have proliferative potential and may be important in vascular regeneration. Currently accepted methods of CEC quantification include the use of immunomagnetic bead separation (with cell counting under fluorescence microscopy) and flow cytometry. Several recent studies have shown increased numbers of CECs in cardiovascular disease and its risk factors, such as unstable angina, acute myocardial infarction, stroke, diabetes mellitus, and critical limb ischemia, but no change in stable intermittent claudication, essential hypertension, or atrial fibrillation. Furthermore, CEC quantification at 48 h after acute myocardial infarction has been shown to be an accurate predictor of major adverse coronary events and death at both 1 month and 1 year. This article presents an overview of the pathophysiology of CECs in the setting of cardiovascular disease and a brief comparison with EPCs. PMID:17045885

  14. Lymphatic endothelial lineage assemblage during corneal lymphangiogenesis.

    PubMed

    Connor, Alicia L; Kelley, Philip M; Tempero, Richard M

    2016-03-01

    Postnatal inflammatory lymphangiogenesis presumably requires precise regulatory processes to properly assemble proliferating lymphatic endothelial cells (LECs). The specific mechanisms that regulate the assembly of LECs during new lymphatic vessel synthesis are unclear. Dynamic endothelial shuffling and rearrangement has been proposed as a mechanism of blood vessel growth. We developed genetic lineage-tracing strategies using an inductive transgenic technology to track the fate of entire tandem dimer tomato-positive (tdT) lymphatic vessels or small, in some cases clonal, populations of LECs. We coupled this platform with a suture-induced mouse model of corneal lymphangiogenesis and used different analytic microscopy techniques including serial live imaging to study the spatial properties of proliferating tdT(+) LEC progenies. LEC precursors and their progeny expanded from the corneal limbal lymphatic vessel and were assembled contiguously to comprise a subunit within a new lymphatic vessel. VE-cadherin blockade induced morphologic abnormalities in newly synthesized lymphatic vessels, but did not disrupt the tdT(+) lymphatic endothelial lineage assembly. Analysis of this static and dynamic data based largely on direct in vivo observations supports a model of lymphatic endothelial lineage assemblage during corneal inflammatory lymphangiogenesis. PMID:26658452

  15. Endothelialized ePTFE Graft by Nanobiotechnology

    ClinicalTrials.gov

    2013-11-29

    The Apparatus for Processing the Tubular Graft Modification Will be Designed and Evaluated.; The On-site Capturing of the Endothelial (Progenitor) Cells by Peptide-mediated Selective Adhesion in Vitro and in Vivo Will Also be Elucidated.; The Patency Rate of ITRI-made Artificial Blood Vessels Will be Evaluated by the Porcine Animal Model.

  16. Endothelial Cell Density to Predict Endothelial Graft Failure After Penetrating Keratoplasty

    PubMed Central

    Lass, Jonathan H.; Sugar, Alan; Benetz, Beth Ann; Beck, Roy W.; Dontchev, Mariya; Gal, Robin L.; Kollman, Craig; Gross, Robert; Heck, Ellen; Holland, Edward J.; Mannis, Mark J.; Raber, Irving; Stark, Walter; Stulting, R. Doyle

    2010-01-01

    Objective To determine whether preoperative and/or postoperative central endothelial cell density (ECD) and its rate of decline postoperatively are predictive of graft failure caused by endothelial decompensation following penetrating keratoplasty to treat a moderate-risk condition, principally, Fuchs dystrophy or pseudophakic corneal edema. Methods In a subset of Cornea Donor Study participants, a central reading center determined preoperative and postoperative ECD from available specular images for 17 grafts that failed because of endothelial decompensation and 483 grafts that did not fail. Results Preoperative ECD was not predictive of graft failure caused by endothelial decompensation (P = .91). However, the 6-month ECD was predictive of subsequent failure (P < .001). Among those that had not failed within the first 6 months, the 5-year cumulative incidence (±95% confidence interval) of failure was 13% (±12%) for the 33 participants with a 6-month ECD of less than 1700 cells/mm2 vs 2%(±3%) for the 137 participants with a 6-monthECDof 2500 cells/mm2 or higher. After 5 years’ follow-up, 40 of 277 participants (14%) with a clear graft had an ECD below 500 cells/mm2. Conclusions Preoperative ECD is unrelated to graft failure from endothelial decompensation, whereas there is a strong correlation of ECD at 6 months with graft failure from endothelial decompensation. A graft can remain clear after 5 years even when the ECD is below 500 cells/mm2. PMID:20065219

  17. Reduced Ang2 expression in aging endothelial cells.

    PubMed

    Hohensinner, P J; Ebenbauer, B; Kaun, C; Maurer, G; Huber, K; Wojta, J

    2016-06-01

    Aging endothelial cells are characterized by increased cell size, reduced telomere length and increased expression of proinflammatory cytokines. In addition, we describe here that aging reduces the migratory distance of endothelial cells. Furthermore, we observe an increase of the quiescence protein Ang1 and a decrease of the endothelial activation protein Ang2 upon aging. Supplementing Ang2 to aged endothelial cells restored their migratory capacity. We conclude that aging shifts the balance of the Ang1/Ang2 network favouring a quiescent state. Activation of endothelial cells in aging might be necessary to enhance wound healing capacities. PMID:27137842

  18. Endothelial TWIST1 Promotes Pathological Ocular Angiogenesis

    PubMed Central

    Li, Jie; Liu, Chi-Hsiu; Sun, Ye; Gong, Yan; Fu, Zhongjie; Evans, Lucy P.; Tian, Katherine T.; Juan, Aimee M.; Hurst, Christian G.; Mammoto, Akiko; Chen, Jing

    2014-01-01

    Purpose. Pathological neovessel formation impacts many blinding vascular eye diseases. Identification of molecular signatures distinguishing pathological neovascularization from normal quiescent vessels is critical for developing new interventions. Twist-related protein 1 (TWIST1) is a transcription factor important in tumor and pulmonary angiogenesis. This study investigated the potential role of TWIST1 in modulating pathological ocular angiogenesis in mice. Methods. Twist1 expression and localization were analyzed in a mouse model of oxygen-induced retinopathy (OIR). Pathological ocular angiogenesis in Tie2-driven conditional Twist1 knockout mice were evaluated in both OIR and laser-induced choroidal neovascularization models. In addition, the effects of TWIST1 on angiogenesis and endothelial cell function were analyzed in sprouting assays of aortic rings and choroidal explants isolated from Twist1 knockout mice, and in human retinal microvascular endothelial cells treated with TWIST1 small interfering RNA (siRNA). Results. TWIST1 is highly enriched in pathological neovessels in OIR retinas. Conditional Tie2-driven depletion of Twist1 significantly suppressed pathological neovessels in OIR without impacting developmental retinal angiogenesis. In a laser-induced choroidal neovascularization model, Twist1 deficiency also resulted in significantly smaller lesions with decreased vascular leakage. In addition, loss of Twist1 significantly decreased vascular sprouting in both aortic ring and choroid explants. Knockdown of TWIST1 in endothelial cells led to dampened expression of vascular endothelial growth factor receptor 2 (VEGFR2) and decreased endothelial cell proliferation. Conclusions. Our study suggests that TWIST1 is a novel regulator of pathologic ocular angiogenesis and may represent a new molecular target for developing potential therapeutic treatments to suppress pathological neovascularization in vascular eye diseases. PMID:25414194

  19. Transport of lipoprotein lipase across endothelial cells

    SciTech Connect

    Saxena, U.; Klein, M.G.; Goldberg, I.J. )

    1991-03-15

    Lipoprotein lipase (LPL), synthesized in muscle and fat, hydrolyzes plasma triglycerides primarily while bound to luminal endothelial cell surfaces. To obtain information about the movement of LPL from the basal to the luminal endothelial cell surface, the authors studied the transport of purified bovine milk LPL across bovine aortic endothelial cell monolayers. {sup 125}I-labeled LPL ({sup 125}I-LPL) added to the basal surface of the monolayers was detected on the apical side of the cells in two compartments: (1) in the medium of the upper chamber, and (2) bound to the apical cell surface. The amount of {sup 125}I-LPL on the cell surface, but not in the medium, reached saturation with time and LPL dose. Catalytically active LPL was transported to the apical surface but very little LPL activity appeared in the medium. Heparinase treatment of the basal cell surface and addition of dextran sulfate to the lower chamber decreased the amount of {sup 125}I-LPL appearing on the apical surface. Similarly, the presence of increasing molar ratios of oleic acid/bovine serum albumin at the basal surface decreased the transport of active LPL across the monolayer. Thus, a saturable transport system, which requires haparan sulfate proteoglycans and is inhibited by high concentrations of free fatty acids on the basal side of the cells, appears to exist for passage of enzymatically active LPL across endothelial cells. They postulate that regulation of LPL transport to the endothelial luminal surface modulates the physiologically active pool of LPL in vivo.

  20. Endothelial cells enhance migration of meniscus cells

    PubMed Central

    Yuan, Xiaoning; Eng, George M.; Arkonac, Derya E.; Chao, Pen-hsiu Grace; Vunjak-Novakovic, Gordana

    2014-01-01

    Objective To study the interactions between vascular endothelial cells and meniscal fibrochondrocytes from the inner avascular and outer vascular regions of the meniscus, and identify angiogenic factors that enhance cell migration and integrative repair. Methods Bovine meniscal fibrochondrocytes (bMFCs) from the inner and outer regions of meniscus were cultured for seven days with and without human umbilical vein endothelial cells (HUVECs) in a micropatterned three-dimensional hydrogel system for cell migration. Angiogenic factors secreted by HUVECs were probed for their role in paracrine mechanisms governing bMFC migration, and applied to a full-thickness defect model of meniscal repair in explants from the inner and outer regions over four weeks. Results Endothelial cells enhanced migration of inner and outer bMFCs in the micropatterned system via endothelin-1 (ET-1) signaling. Supplementation of ET-1 significantly enhanced integration strength of full-thickness defects in inner and outer explants, and cell migration at the macro-scale, compared to controls without ET-1 treatment. Conclusion We report for the first time that bMFCs from both the avascular and vascular regions respond to the presence of endothelial cells with increased migration. Paracrine signaling by endothelial cells regulates the bMFCs differentially by region, but we identify ET-1 as an angiogenic factor that stimulates migration of inner and outer cells at the micro-scale, and integrative repair of inner and outer explants at the macro-scale. These findings reveal the regional interactions between vasculature and MFCs, and suggest ET-1 as a potential new treatment modality for avascular meniscal injuries, in order to prevent the development of osteoarthritis. PMID:25307081

  1. 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

  2. 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. PMID:27612188

  3. Phagocytosis of platelets enhances endothelial cell survival under serum deprivation.

    PubMed

    Jiang, Ping; Ren, Ya-Li; Lan, Yong; Li, Jia-Liang; Luo, Jun; Li, Jian; Cai, Jian-Ping

    2015-07-01

    Platelets are key players in fundamental processes of vascular biology, such as angiogenesis, tissue regeneration, and tumor metastasis. However, the underlying mechanisms remain unclear. In this study, some tumor vascular endothelial cells were positively stained by antiplatelet antibodies. Further investigation revealed that platelets were taken up by endothelial cells in vitro and in vivo. Human umbilical vascular endothelial cells were rendered apoptotic under conditions of serum deprivation. However, endothelial apoptosis was suppressed and cell viability was enhanced when platelets were added to the cultures. Endothelial survival was paralleled by an upregulation of phosphorylated Akt and p70 S6K. In conclusion, this study demonstrated that platelets can be phagocytosed by endothelial cells, and the phagocytosed platelets could suppress endothelial apoptosis and promote cell viability level. The mechanism underlying this process involves the activation of Akt signaling.

  4. The role of H2S bioavailability in endothelial dysfunction

    PubMed Central

    Wang, Rui; Szabo, Csaba; Ichinose, Fumito; Ahmed, Asif; Whiteman, Matthew; Papapetropoulos, Andreas

    2015-01-01

    Endothelial dysfunction reflects pathophysiological changes in the phenotype and functions of endothelial cells that result from and/or contribute to a plethora of cardiovascular diseases. Here we review the role of hydrogen sulfide (H2S) in the pathogenesis of endothelial dysfunction, one of the fastest advanced and hottest research topics. Conventionally treated as an environment pollutant, H2S is also produced in endothelial cells and participates in the fine regulation of endothelial integrity and functions. Disturbed H2S bioavailability has been suggested to be a novel indicator of the progress and prognosis of endothelial dysfunction. Endothelial dysfunction appears to exhibit in different forms in different pathologies but therapeutics aimed at remedying the altered H2S bioavailability may benefit all. PMID:26071118

  5. Phagocytosis of platelets enhances endothelial cell survival under serum deprivation

    PubMed Central

    Ren, Ya-Li; Lan, Yong; Li, Jia-Liang; Luo, Jun; Li, Jian; Cai, Jian-Ping

    2015-01-01

    Platelets are key players in fundamental processes of vascular biology, such as angiogenesis, tissue regeneration, and tumor metastasis. However, the underlying mechanisms remain unclear. In this study, some tumor vascular endothelial cells were positively stained by antiplatelet antibodies. Further investigation revealed that platelets were taken up by endothelial cells in vitro and in vivo. Human umbilical vascular endothelial cells were rendered apoptotic under conditions of serum deprivation. However, endothelial apoptosis was suppressed and cell viability was enhanced when platelets were added to the cultures. Endothelial survival was paralleled by an upregulation of phosphorylated Akt and p70 S6K. In conclusion, this study demonstrated that platelets can be phagocytosed by endothelial cells, and the phagocytosed platelets could suppress endothelial apoptosis and promote cell viability level. The mechanism underlying this process involves the activation of Akt signaling. PMID:25577801

  6. Targeted endothelial nanomedicine for common acute pathological conditions.

    PubMed

    Shuvaev, Vladimir V; Brenner, Jacob S; Muzykantov, Vladimir R

    2015-12-10

    Endothelium, a thin monolayer of specialized cells lining the lumen of blood vessels is the key regulatory interface between blood and tissues. Endothelial abnormalities are implicated in many diseases, including common acute conditions with high morbidity and mortality lacking therapy, in part because drugs and drug carriers have no natural endothelial affinity. Precise endothelial drug delivery may improve management of these conditions. Using ligands of molecules exposed to the bloodstream on the endothelial surface enables design of diverse targeted endothelial nanomedicine agents. Target molecules and binding epitopes must be accessible to drug carriers, carriers must be free of harmful effects, and targeting should provide desirable sub-cellular addressing of the drug cargo. The roster of current candidate target molecules for endothelial nanomedicine includes peptidases and other enzymes, cell adhesion molecules and integrins, localized in different domains of the endothelial plasmalemma and differentially distributed throughout the vasculature. Endowing carriers with an affinity to specific endothelial epitopes enables an unprecedented level of precision of control of drug delivery: binding to selected endothelial cell phenotypes, cellular addressing and duration of therapeutic effects. Features of nanocarrier design such as choice of epitope and ligand control delivery and effect of targeted endothelial nanomedicine agents. Pathological factors modulate endothelial targeting and uptake of nanocarriers. Selection of optimal binding sites and design features of nanocarriers are key controllable factors that can be iteratively engineered based on their performance from in vitro to pre-clinical in vivo experimental models. Targeted endothelial nanomedicine agents provide antioxidant, anti-inflammatory and other therapeutic effects unattainable by non-targeted counterparts in animal models of common acute severe human disease conditions. The results of animal

  7. 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.

  8. Androgen receptor in human endothelial cells

    PubMed Central

    Torres-Estay, Verónica; Carreño, Daniela V; San Francisco, Ignacio F; Sotomayor, Paula; Godoy, Alejandro S; Smith, Gary J

    2015-01-01

    Androgen receptor (AR) is a ligand-inducible transcription factor, and a member of the steroid-thyroid-retinoid receptor superfamily, that mediates the biological effects of androgens in a wide range of physiological and pathological processes. AR expression was identified in vascular cells nearly 20 years ago, and recent research has shown that AR mediates a variety of actions of androgens in endothelial and vascular smooth muscle cells. In this mini-review, we review evidence indicating the importance of AR in human endothelial cell (HUVEC) homeostatic and pathogenic processes. Although a role for AR in the modulation of HUVEC biology is evident, the molecular mechanisms by which AR regulates HUVEC homeostasis and disease processes are not fully understood. Understanding these mechanisms could provide critical insights into the processes of pathogenesis of diseases ranging from cardiovascular disease to cancer that are major causes of human morbidity and mortality. PMID:25563353

  9. Endothelial progenitor cell dysfunction in rheumatic disease.

    PubMed

    Westerweel, Peter E; Verhaar, Marianne C

    2009-06-01

    Rheumatic disease is characterized by inflammation and endothelial dysfunction, which contribute to accelerated atherosclerosis. Circulating endothelial progenitor cells (EPCs) can restore dysfunctional endothelium and thereby protect against atherosclerotic vascular disease. The number and function of EPCs are, however, affected in rheumatic diseases such as psoriatic arthritis, rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, and antineutrophil cytoplasmic autoantibody-associated vasculitis. rheumatic disease is often characterized by decreased numbers, and impaired function, of EPCs, although numbers of these cells might increase during the initial years of systemic sclerosis. Pioneering studies show that EPC dysfunction might be improved with pharmacological treatment. How best to restore EPC function, and whether achieving this aim can prevent long-term cardiovascular complications in rheumatic disease, remain to be established.

  10. Activation of Endothelial Nitric Oxide (eNOS) Occurs through Different Membrane Domains in Endothelial Cells.

    PubMed

    Tran, Jason; Magenau, Astrid; Rodriguez, Macarena; Rentero, Carles; Royo, Teresa; Enrich, Carlos; Thomas, Shane R; Grewal, Thomas; Gaus, Katharina

    2016-01-01

    Endothelial cells respond to a large range of stimuli including circulating lipoproteins, growth factors and changes in haemodynamic mechanical forces to regulate the activity of endothelial nitric oxide synthase (eNOS) and maintain blood pressure. While many signalling pathways have been mapped, the identities of membrane domains through which these signals are transmitted are less well characterized. Here, we manipulated bovine aortic endothelial cells (BAEC) with cholesterol and the oxysterol 7-ketocholesterol (7KC). Using a range of microscopy techniques including confocal, 2-photon, super-resolution and electron microscopy, we found that sterol enrichment had differential effects on eNOS and caveolin-1 (Cav1) colocalisation, membrane order of the plasma membrane, caveolae numbers and Cav1 clustering. We found a correlation between cholesterol-induced condensation of the plasma membrane and enhanced high density lipoprotein (HDL)-induced eNOS activity and phosphorylation suggesting that cholesterol domains, but not individual caveolae, mediate HDL stimulation of eNOS. Vascular endothelial growth factor (VEGF)-induced and shear stress-induced eNOS activity was relatively independent of membrane order and may be predominantly controlled by the number of caveolae on the cell surface. Taken together, our data suggest that signals that activate and phosphorylate eNOS are transmitted through distinct membrane domains in endothelial cells.

  11. Ulinastatin attenuates pulmonary endothelial glycocalyx damage and inhibits endothelial heparanase activity in LPS-induced ARDS.

    PubMed

    Wang, Lipeng; Huang, Xiao; Kong, Guiqing; Xu, Haixiao; Li, Jiankui; Hao, Dong; Wang, Tao; Han, Shasha; Han, Chunlei; Sun, Yeying; Liu, Xiangyong; Wang, Xiaozhi

    2016-09-16

    Acute respiratory distress syndrome (ARDS) is a syndrome of acute respiratory failure characterized by major pathologic mechanisms of increased microvascular permeability and inflammation. The glycocalyx lines on the endothelial surface, which determines the vascular permeability, and heparanase play pivotal roles in the degradation of heparan sulfate (HS). HS is the major component of the glycocalyx. The aim of this study is to examine the effects of Ulinastatin (UTI) on vascular permeability and pulmonary endothelial glycocalyx dysfunction induced by lipopolysaccharide (LPS). In our study, C57BL/6 mice and human umbilical vein endothelial cells were stimulated with LPS to induce injury models. After 6 h of LPS stimulation, pulmonary pathological changes, pulmonary edema, and vascular permeability were notably attenuated by UTI. UTI inhibited LPS-induced endothelial glycocalyx destruction and significantly decreased the production of HS as determined by ELISA and immunofluorescence. UTI also reduced the active form of heparanase (50 kDa) expression and heparanase activity. Moreover, lysosome pH was investigated because heparanase (65 kDa) can be reduced easily in its active form at 50 kDa in a low pH environment within lysosome. Results showed that UTI could inhibit LPS-induced pH elevation in lysosome. In conclusion, UTI protects pulmonary endothelial glycocalyx integrity and inhibits heparanase activity during LPS-induced ARDS.

  12. Activation of Endothelial Nitric Oxide (eNOS) Occurs through Different Membrane Domains in Endothelial Cells.

    PubMed

    Tran, Jason; Magenau, Astrid; Rodriguez, Macarena; Rentero, Carles; Royo, Teresa; Enrich, Carlos; Thomas, Shane R; Grewal, Thomas; Gaus, Katharina

    2016-01-01

    Endothelial cells respond to a large range of stimuli including circulating lipoproteins, growth factors and changes in haemodynamic mechanical forces to regulate the activity of endothelial nitric oxide synthase (eNOS) and maintain blood pressure. While many signalling pathways have been mapped, the identities of membrane domains through which these signals are transmitted are less well characterized. Here, we manipulated bovine aortic endothelial cells (BAEC) with cholesterol and the oxysterol 7-ketocholesterol (7KC). Using a range of microscopy techniques including confocal, 2-photon, super-resolution and electron microscopy, we found that sterol enrichment had differential effects on eNOS and caveolin-1 (Cav1) colocalisation, membrane order of the plasma membrane, caveolae numbers and Cav1 clustering. We found a correlation between cholesterol-induced condensation of the plasma membrane and enhanced high density lipoprotein (HDL)-induced eNOS activity and phosphorylation suggesting that cholesterol domains, but not individual caveolae, mediate HDL stimulation of eNOS. Vascular endothelial growth factor (VEGF)-induced and shear stress-induced eNOS activity was relatively independent of membrane order and may be predominantly controlled by the number of caveolae on the cell surface. Taken together, our data suggest that signals that activate and phosphorylate eNOS are transmitted through distinct membrane domains in endothelial cells. PMID:26977592

  13. Vascular Endothelial Function & Self-Reported Sleep

    PubMed Central

    Behl, Muskaan; Bliwise, Donald; Veledar, Emir; Cunningham, Lynn; Vazquez, Jennifer; Brigham, Kenneth; Quyyumi, Arshed

    2013-01-01

    Background We investigated the relationship between self-reported sleep characteristics and brachial artery flow-mediated dilation (FMD) in a community-based population. Prior studies document that sleep apnea may be related to endothelial dysfunction but disagree whether subjective reports of sleep may also reflect such associations. Methods In 684 subjects (32% male) between 37 and 60 years enrolled in the Emory-Georgia Tech Predictive Health Institute study, we measured reported sleep characteristics using the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI) along with cardiovascular risk factors. Endothelial function was assessed using brachial artery FMD. Multivariate analysis of covariance was used to adjust for various cardiovascular risk factors including age, race, gender, smoking, hypertension, diabetes, and body mass index. Results Lower brachial artery FMD values were correlated with higher ESS scores (p = 0.0275), even after adjustment for risk factors (p = 0.03). Total PSQI score was unrelated to brachial artery FMD. However, lower sleep quality (PSQI component 1) was associated with lower brachial artery FMD (multivariate p = 0.038), and participants who coughed or snored during sleep also had lower brachial artery FMD (6.24±3.42%) compared to those who did not (6.92±4.30%) (p = 0.056). This difference remained significant after adjustment for risk factors (p = 0.03). Conclusion In a community-based population, our analysis indicates a significant association between sleepiness and snoring assessed by questionnaires and endothelial function. Simple subjective reports about individuals’ sleep may be highly revealing indicators of endothelial function impairment and thus important indicators of cardiovascular disease risk. PMID:23842206

  14. ADP Signaling in Vascular Endothelial Cells

    PubMed Central

    Hess, Connie Ng; Kou, Ruqin; Johnson, Rosalyn P.; Li, Gordon K.; Michel, Thomas

    2009-01-01

    ADP responses underlie therapeutic approaches to many cardiovascular diseases, and ADP receptor antagonists are in widespread clinical use. The role of ADP in platelet biology has been extensively studied, yet ADP signaling pathways in endothelial cells remain incompletely understood. We found that ADP promoted phosphorylation of the endothelial isoform of nitric-oxide synthase (eNOS) at Ser1179 and Ser635 and dephosphorylation at Ser116 in cultured endothelial cells. Although eNOS activity was stimulated by both ADP and ATP, only ADP signaling was significantly inhibited by the P2Y1 receptor antagonist MRS 2179 or by knockdown of P2Y1 using small interfering RNA (siRNA). ADP activated the small GTPase Rac1 and promoted endothelial cell migration. siRNA-mediated knockdown of Rac1 blocked ADP-dependent eNOS Ser1179 and Ser635 phosphorylation, as well as eNOS activation. We analyzed pathways known to regulate eNOS, including phosphoinositide 3-kinase/Akt, ERK1/2, Src, and calcium/calmodulin-dependent kinase kinase-β (CaMKKβ) using the inhibitors wortmannin, PD98059, PP2, and STO-609, respectively. None of these inhibitors altered ADP-modulated eNOS phosphorylation. In contrast, siRNA-mediated knockdown of AMP-activated protein kinase (AMPK) inhibited ADP-dependent eNOS Ser635 phosphorylation and eNOS activity but did not affect eNOS Ser1179 phosphorylation. Importantly, the AMPK enzyme inhibitor compound C had no effect on ADP-stimulated eNOS activity, despite completely blocking AMPK activity. CaMKKβ knockdown suppressed ADP-stimulated eNOS activity, yet inhibition of CaMKKβ kinase activity using STO-609 failed to affect eNOS activation by ADP. These data suggest that the expression, but not the kinase activity, of AMPK and CaMKKβ is necessary for ADP signaling to eNOS. PMID:19783664

  15. Schwann cells promote endothelial cell migration

    PubMed Central

    Ramos, Tiago; Ahmed, Maqsood; Wieringa, Paul; Moroni, Lorenzo

    2015-01-01

    Directed cell migration is a crucial orchestrated process in embryonic development, wound healing, and immune response. The underlying substrate can provide physical and/or chemical cues that promote directed cell migration. Here, using electrospinning we developed substrates of aligned poly(lactic-co-glycolic acid) nanofibres to study the influence of glial cells on endothelial cells (ECs) in a 3-dimensional (3D) co-culture model. ECs build blood vessels and regulate their plasticity in coordination with neurons. Likewise, neurons construct nerves and regulate their circuits in coordination with ECs. In our model, the neuro-vascular cross-talk was assessed using a direct co-culture model of human umbilical vein endothelial cells (HUVECs) and rat Schwann cells (rSCs). The effect of rSCs on ECs behavior was demonstrated by earlier and higher velocity values and genetic expression profiles different of those of HUVECs when seeded alone. We observed 2 different gene expression trends in the co-culture models: (i) a later gene expression of angiogenic factors, such as interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF), and (ii) an higher gene expression of genes involved in actin filaments rearrangement, such as focal adhesion kinase (FAK), Mitogen-activated protein kinase-activated protein kinase 13 (MAPKAPK13), Vinculin (VCL), and Profilin (PROF). These results suggested that the higher ECs migration is mainly due to proteins involved in the actin filaments rearrangement and in the directed cell migration rather than the effect of angiogenic factors. This co-culture model provides an approach to enlighten the neurovascular interactions, with particular focus on endothelial cell migration. PMID:26491999

  16. [Endothelial microparticles (EMP) in physiology and pathology].

    PubMed

    Sierko, Ewa; Sokół, Monika; Wojtukiewicz, Marek Z

    2015-08-18

    Endothelial microparticles (EMP) are released from endothelial cells (ECs) in the process of activation and/or apoptosis. They harbor adhesive molecules, enzymes, receptors and cytoplasmic structures and express a wide range of various constitutive antigens, typical for ECs, at their surface. Under physiological conditions the concentration of EMP in the blood is clinically insignificant. However, it was reported that under pathological conditions EMP concentration in the blood might slightly increase and contribute to blood coagulation, angiogenesis and inflammation. It has been shown that EMP directly and indirectly contribute to the activation of blood coagulation. Endothelial microparticles directly participate in blood coagulation through their surface tissue factor (TF) - a major initiator of blood coagulation. Furthermore, EMP exhibit procoagulant potential via expression of negatively charged phospholipids at their surface, which may promote assembly of coagulation enzymes (TF/VII, tenases and prothrombinase complexes), leading to thrombus formation. In addition, they provide a binding surface for coagulation factors: IXa, VIII, Va and IIa. Moreover, it is possible that EMP transfer TF from TF-bearing EMP to activated platelets and monocytes by binding them through adhesion molecules. Also, EMP express von Willebrand factor, which may facilitate platelet aggregation. Apart from their procoagulant properties, it was demonstrated that EMP may express adhesive molecules and metalloproteinases (MMP-2, MMP-9) at their surface and release growth factors, which may contribute to angiogenesis. Additionally, surface presence of C3 and C4 - components of the classical pathway - suggests pro-inflammatory properties of these structures. This article contains a summary of available data on the biology and pathophysiology of endothelial microparticles and their potential role in blood coagulation, angiogenesis and inflammation.

  17. Endothelial Mechanosignaling: Does One Sensor Fit All?

    PubMed Central

    Givens, Chris

    2016-01-01

    Abstract Significance: Forces are important in the cardiovascular system, acting as regulators of vascular physiology and pathology. Residing at the blood vessel interface, cells (endothelial cell, EC) are constantly exposed to vascular forces, including shear stress. Shear stress is the frictional force exerted by blood flow, and its patterns differ based on vessel geometry and type. These patterns range from uniform laminar flow to nonuniform disturbed flow. Although ECs sense and differentially respond to flow patterns unique to their microenvironment, the mechanisms underlying endothelial mechanosensing remain incompletely understood. Recent Advances: A large body of work suggests that ECs possess many mechanosensors that decorate their apical, junctional, and basal surfaces. These potential mechanosensors sense blood flow, translating physical force into biochemical signaling events. Critical Issues: Understanding the mechanisms by which proposed mechanosensors sense and respond to shear stress requires an integrative approach. It is also critical to understand the role of these mechanosensors not only during embryonic development but also in the different vascular beds in the adult. Possible cross talk and integration of mechanosensing via the various mechanosensors remain a challenge. Future Directions: Determination of the hierarchy of endothelial mechanosensors is critical for future work, as is determination of the extent to which mechanosensors work together to achieve force-dependent signaling. The role and primary sensors of shear stress during development also remain an open question. Finally, integrative approaches must be used to determine absolute mechanosensory function of potential mechanosensors. Antioxid. Redox Signal. 25, 373–388. PMID:27027326

  18. Endothelial Matrix Assembly during Capillary Morphogenesis

    PubMed Central

    Chang, Fumin; Lemmon, Christopher A.; Nilaratanakul, Voraphoj; Rotter, Varda

    2014-01-01

    Biologically relevant, three-dimensional extracellular matrix is an essential component of in vitro vasculogenesis models. WI-38 fibroblasts assemble a 3D matrix that induces endothelial tubulogenesis, but this model is challenged by fibroblast senescence and the inability to distinguish endothelial cell-derived matrix from matrix made by WI-38 fibroblasts. Matrices produced by hTERT-immortalized WI-38 recapitulated those produced by wild type fibroblasts. ECM fibrils were heavily populated by tenascin-C, fibronectin, and type VI collagen. Nearly half of the total type I collagen, but only a small fraction of the type IV collagen, were incorporated into ECM. Stable hTERT-WI-38 transfectants expressing TagRFP-fibronectin incorporated TagRFP into ~90% of the fibronectin in 3D matrices. TagRFP-fibronectin colocalized with tenascin-C and with type I collagen in a pattern that was similar to that seen in matrices from wild type WI-38. Human Umbilical Vein Endothelial Cells (HUVEC) formed 3D adhesions and tubes on WI38-hTERT-TagRFP-FN-derived matrices, and the TagRFP-fibronectin component of this new 3D human fibroblast matrix model facilitated the demonstration of concentrated membrane type 1 metalloprotease and new HUVEC FN and collagen type IV fibrils during EC tubulogenesis. These findings indicate that WI-38-hTERT- and WI-38-hTERT-TagRFP-FN-derived matrices provide platforms for the definition of new matrix assembly and remodeling events during vasculogenesis. PMID:25063001

  19. Viscoelastic response of a model endothelial glycocalyx

    NASA Astrophysics Data System (ADS)

    Nijenhuis, Nadja; Mizuno, Daisuke; Spaan, Jos A. E.; Schmidt, Christoph F.

    2009-06-01

    Many cells cover themselves with a multifunctional polymer coat, the pericellular matrix (PCM), to mediate mechanical interactions with the environment. A particular PCM, the endothelial glycocalyx (EG), is formed by vascular endothelial cells at their luminal side, forming a mechanical interface between the flowing blood and the endothelial cell layer. The glycosaminoglycan (GAG) hyaluronan (HA) is involved in the main functions of the EG, mechanotransduction of fluid shear stress and molecular sieving. HA, due to its length, is the only GAG in the EG or any other PCM able to form an entangled network. The mechanical functions of the EG are, however, impaired when any one of its components is removed. We here used microrheology to measure the effect of the EG constituents heparan sulfate, chondroitin sulfate, whole blood plasma and albumin on the high-bandwidth mechanical properties of a HA solution. Furthermore, we probed the effect of the hyaldherin aggrecan, a constituent of the PCM of chondrocytes, and very similar to versican (present in the PCM of various cells, and possibly in the EG). We show that components directly interacting with HA (chondroitin sulfate and aggrecan) can increase the viscoelastic shear modulus of the polymer composite.

  20. Isolation of Murine Embryonic Hemogenic Endothelial Cells

    PubMed Central

    Marcelo, Kathrina L.; Hirschi, Karen K.

    2016-01-01

    The specification of hemogenic endothelial cells from embryonic vascular endothelium occurs during brief developmental periods within distinct tissues, and is necessary for the emergence of definitive HSPC from the murine extra embryonic yolk sac, placenta, umbilical vessels, and the embryonic aorta-gonad-mesonephros (AGM) region. The transient nature and small size of this cell population renders its reproducible isolation for careful quantification and experimental applications technically difficult. We have established a fluorescence-activated cell sorting (FACS)-based protocol for simultaneous isolation of hemogenic endothelial cells and HSPC during their peak generation times in the yolk sac and AGM. We demonstrate methods for dissection of yolk sac and AGM tissues from mouse embryos, and we present optimized tissue digestion and antibody conjugation conditions for maximal cell survival prior to identification and retrieval via FACS. Representative FACS analysis plots are shown that identify the hemogenic endothelial cell and HSPC phenotypes, and describe a methylcellulose-based assay for evaluating their blood forming potential on a clonal level. PMID:27341393

  1. [The role of endothelial lipase in atherogenesis].

    PubMed

    Pierart Z, Camila; Serrano L, Valentina

    2012-03-01

    Endothelial lipase (EL) is synthetized by endothelial cells and its main substrates are lipoprotein phospholipids. Over expression of EL reduces high density lipoprotein (HDL) cholesterol and phospholipids, in vivo and in vitro. Inhibition of the enzyme achieves the opposite effects. The synthesis of the enzyme is regulated by interleukin 1 and tumor necrosis factor a. These inflammatory cytokines play a role in diabetes and vascular disease. An increase in vascular mechanical forces, that play a role in atherogenesis, also increase the synthesis of EL. There is expression of EL in endothelial cells, macrophages and muscle cells of atherosclerotic lesions of coronary arteries of humans. This evidence leads to the suspicion that EL plays a role in atherogenesis. There are also higher plasma levels of EL in subjects with type 2 diabetes, who are especially susceptible to the development of vascular lesions. Therefore the inhibition of EL could play an important role in HDL metabolism and could be a new therapeutic strategy for the prevention of atherosclerosis. PMID:22689120

  2. Electrical method for detection of endothelial cell shape change in real time: assessment of endothelial barrier function.

    PubMed Central

    Tiruppathi, C; Malik, A B; Del Vecchio, P J; Keese, C R; Giaever, I

    1992-01-01

    We have developed an electrical method to study endothelial cell shape changes in real time in order to examine the mechanisms of alterations in the endothelial barrier function. Endothelial shape changes were quantified by using a monolayer of endothelial cells grown on a small (10(-3) cm2) evaporated gold electrode and measuring the changes in electrical impedance. Bovine pulmonary microvessel endothelial cells and bovine pulmonary artery endothelial cells were used to study the effects of alpha-thrombin on cell-shape dynamics by the impedance measurement. alpha-Thrombin produced a dose-dependent decrease in impedance that occurred within 0.5 min in both cell types, indicative of retraction of endothelial cells and widening of interendothelial junctions because of "rounding up" of the cells. The alpha-thrombin-induced decrease in impedance persisted for approximately 2 hr, after which the value recovered to basal levels. Pretreatment of endothelial cells with the protein kinase C inhibitor, calphostin C, or with 8-bromoadenosine 3',5'-cyclic monophosphate prevented the decreased impedance, suggesting that the endothelial cell change is modulated by activation of second-messenger pathways. The alpha-thrombin-induced decrease in impedance was in agreement with the previously observed increases in transendothelial albumin permeability and evidence of formation of intercellular gaps after alpha-thrombin challenge. The impedance measurement may be a valuable in vitro method for the assessment of mechanisms of decreased endothelial barrier function occurring with inflammatory mediators. Since the rapidly occurring changes in endothelial cell shape in response to mediators such as thrombin are mediated activation of second-messenger pathways, the ability to monitor endothelial cell dynamics in real time may provide insights into the signal-transduction events mediating the increased endothelial permeability. PMID:1518814

  3. Conserved signaling through vascular endothelial growth (VEGF) receptor family members in murine lymphatic endothelial cells.

    PubMed

    Coso, Sanja; Zeng, Yiping; Sooraj, Dhanya; Williams, Elizabeth D

    2011-10-15

    Lymphatic vessels guide interstitial fluid, modulate immune responses by regulating leukocyte and antigen trafficking to lymph nodes, and in a cancer setting enable tumor cells to track to regional lymph nodes. The aim of the study was to determine whether primary murine lymphatic endothelial cells (mLECs) show conserved vascular endothelial growth factor (VEGF) signaling pathways with human LECs (hLECs). LECs were successfully isolated from murine dermis and prostate. Similar to hLECs, vascular endothelial growth factor (VEGF) family ligands activated MAPK and pAkt intracellular signaling pathways in mLECs. We describe a robust protocol for isolation of mLECs which, by harnessing the power of transgenic and knockout mouse models, will be a useful tool to study how LEC phenotype contributes to alterations in lymphatic vessel formation and function.

  4. 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

  5. Descemet stripping and endothelial keratoplasty in endothelial dysfunctions: Three-month results in 75 eyes

    PubMed Central

    2008-01-01

    Purpose: To analyze the results of Descemet stripping and endothelial keratoplasty (DSEK) in the first consecutive 75 cases. Materials and Methods: Prospective, non-randomized, non-comparative interventional case series. Seventy- five eyes of 75 patients with endothelial dysfunctions of different etiology, scheduled for DSEK, were included in this study. Healthy donor cornea with a cell count of >2000 cells/sq mm was considered for transplantation in each case. Indications, operative problems and postoperative complications were noted. Best corrected visual acuity (BCVA), refractive and keratometric astigmatism, central corneal thickness (CCT) and endothelial cell density (ECD) were analyzed for each patient after a minimum follow-up of three months. Results: Main indication was pseudophakic corneal edema and bullous keratopathy in 53 (70.7%) eyes. Seventeen (22.7%) cases had moderate to severe Fuchs′ dystrophy with various grades of cataract; and DSEK was combined with manual small-incision cataract surgery (MSICS) with posterior chamber intraocular lens (PCIOL) in those cases. After three months, BCVA was 20/60 or better in 62 (82.7%) cases. Mean refractive and keratometric astigmatism were 1.10 ± 0.55 diopter cylinder (DCyl) and 1.24 ± 0.92 DCyl. The CCT and ECD were 670.8 ± 0.32 µm and 1485.6 ± 168.6/sq mm respectively. The mean endothelial cell loss after three months was 26.8 ± 4.24% (range: 13.3-38.4%). Dislocation of donor lenticule occurred in six (8.0%) eyes. Graft failure occurred in one case. Conclusions: Descemet stripping and endothelial keratoplasty is a safe and effective procedure in patients with endothelial dysfunctions with encouraging surgical and visual outcomes. It can be safely combined with MSICS with PCIOL in patients with moderate to severe Fuchs′ dystrophy with cataract. PMID:18579987

  6. Radiation Effects on the Cytoskeleton of Endothelial Cells and Endothelial Monolayer Permeability

    SciTech Connect

    Gabrys, Dorota; Greco, Olga; Patel, Gaurang; Prise, Kevin M.; Tozer, Gillian M.; Kanthou, Chryso

    2007-12-01

    Purpose: To investigate the effects of radiation on the endothelial cytoskeleton and endothelial monolayer permeability and to evaluate associated signaling pathways, which could reveal potential mechanisms of known vascular effects of radiation. Methods and Materials: Cultured endothelial cells were X-ray irradiated, and actin filaments, microtubules, intermediate filaments, and vascular endothelial (VE)-cadherin junctions were examined by immunofluorescence. Permeability was determined by the passage of fluorescent dextran through cell monolayers. Signal transduction pathways were analyzed using RhoA, Rho kinase, and stress-activated protein kinase-p38 (SAPK2/p38) inhibitors by guanosine triphosphate-RhoA activation assay and transfection with RhoAT19N. The levels of junction protein expression and phosphorylation of myosin light chain and SAPK2/p38 were assessed by Western blotting. The radiation effects on cell death were verified by clonogenic assays. Results: Radiation induced rapid and persistent actin stress fiber formation and redistribution of VE-cadherin junctions in microvascular, but not umbilical vein endothelial cells, and microtubules and intermediate filaments remained unaffected. Radiation also caused a rapid and persistent increase in microvascular permeability. RhoA-guanosine triphosphatase and Rho kinase were activated by radiation and caused phosphorylation of downstream myosin light chain and the observed cytoskeletal and permeability changes. SAPK2/p38 was activated by radiation but did not influence either the cytoskeleton or permeability. Conclusion: This study is the first to show rapid activation of the RhoA/Rho kinase by radiation in endothelial cells and has demonstrated a link between this pathway and cytoskeletal remodeling and permeability. The results also suggest that the RhoA pathway might be a useful target for modulating the permeability and other effects of radiation for therapeutic gain.

  7. MicroRNA-34a regulation of endothelial senescence

    SciTech Connect

    Ito, Takashi; Yagi, Shusuke; Yamakuchi, Munekazu

    2010-08-06

    Research highlights: {yields} MicroRNA-34a (miR-34a) regulates senescence and cell cycle progression in endothelial cells. {yields} MiR-34a expression increases during endothelial cell senescence and in older mice. {yields} SIRT1 is a miR-34a target gene in endothelial cells. {yields} SIRT1 mediates the effects of miR-34a upon cell senescence in endothelial cells. -- Abstract: Endothelial senescence is thought to play a role in cardiovascular diseases such as atherosclerosis. We hypothesized that endothelial microRNAs (miRNAs) regulate endothelial survival and senescence. We found that miR-34a is highly expressed in primary endothelial cells. We observed that miR-34a expression increases in senescent human umbilical cord vein endothelial cells (HUVEC) and in heart and spleen of older mice. MiR-34a over-expression induces endothelial cell senescence and also suppresses cell proliferation by inhibiting cell cycle progression. Searching for how miR-34a affects senescence, we discovered that SIRT1 is a target of miR-34a. Over-expressing miR-34a inhibits SIRT1 protein expression, and knocking down miR-34a enhances SIRT1 expression. MiR-34a triggers endothelial senescence in part through SIRT1, since forced expression of SIRT1 blocks the ability of miR-34a to induce senescence. Our data suggest that miR-34a contributes to endothelial senescence through suppression of SIRT1.

  8. Endothelial Cell Implantation and Survival within Experimental Gliomas

    NASA Astrophysics Data System (ADS)

    Lal, Bachchu; Indurti, Ravi R.; Couraud, Pierre-Olivier; Goldstein, Gary W.; Laterra, John

    1994-10-01

    The delivery of therapeutic genes to primary brain neoplasms opens new opportunities for treating these frequently fatal tumors. Efficient gene delivery to tissues remains an important obstacle to therapy, and this problem has unique characteristics in brain tumors due to the blood-brain and blood-tumor barriers. The presence of endothelial mitogens and vessel proliferation within solid tumors suggests that genetically modified endothelial cells might efficiently transplant to brain tumors. Rat brain endothelial cells immortalized with the adenovirus E1A gene and further modified to express the β-galactosidase reporter were examined for their ability to survive implantation to experimental rat gliomas. Rats received 9L, F98, or C6 glioma cells in combination with endothelial cells intracranially to caudate/putamen or subcutaneously to flank. Implanted endothelial cells were identified by β-galactosidase histochemistry or by polymerase chain reaction in all tumors up to 35 days postimplantation, the latest time examined. Implanted endothelial cells appeared to cooperate in tumor vessel formation and expressed the brain-specific endothelial glucose transporter type 1 as identified by immunohistochemistry. The proliferation of implanted endothelial cells was supported by their increased number within tumors between postimplantation days 14 and 21 (P = 0.015) and by their expression of the proliferation antigen Ki67. These findings establish that genetically modified endothelial cells can be stably engrafted to growing gliomas and suggest that endothelial cell implantation may provide a means of delivering therapeutic genes to brain neoplasms and other solid tumors. In addition, endothelial implantation to brain may be useful for defining mechanisms of brain-specific endothelial differentiation.

  9. Sickle erythrocytes inhibit human endothelial cell DNA synthesis

    SciTech Connect

    Weinstein, R.; Zhou, M.A.; Bartlett-Pandite, A.; Wenc, K. )

    1990-11-15

    Patients with sickle cell anemia experience severe vascular occlusive phenomena including acute pain crisis and cerebral infarction. Obstruction occurs at both the microvascular and the arterial level, and the clinical presentation of vascular events is heterogeneous, suggesting a complex etiology. Interaction between sickle erythrocytes and the endothelium may contribute to vascular occlusion due to alteration of endothelial function. To investigate this hypothesis, human vascular endothelial cells were overlaid with sickle or normal erythrocytes and stimulated to synthesize DNA. The erythrocytes were sedimented onto replicate monolayers by centrifugation for 10 minutes at 17 g to insure contact with the endothelial cells. Incorporation of 3H-thymidine into endothelial cell DNA was markedly inhibited during contact with sickle erythrocytes. This inhibitory effect was enhanced more than twofold when autologous sickle plasma was present during endothelial cell labeling. Normal erythrocytes, with or without autologous plasma, had a modest effect on endothelial cell DNA synthesis. When sickle erythrocytes in autologous sickle plasma were applied to endothelial monolayers for 1 minute, 10 minutes, or 1 hour and then removed, subsequent DNA synthesis by the endothelial cells was inhibited by 30% to 40%. Although adherence of sickle erythrocytes to the endothelial monolayers was observed under these experimental conditions, the effect of sickle erythrocytes on endothelial DNA synthesis occurred in the absence of significant adherence. Hence, human endothelial cell DNA synthesis is partially inhibited by contact with sickle erythrocytes. The inhibitory effect of sickle erythrocytes occurs during a brief (1 minute) contact with the endothelial monolayers, and persists for at least 6 hours of 3H-thymidine labeling.

  10. Endothelial glycocalyx on brain endothelial cells is lost in experimental cerebral malaria.

    PubMed

    Hempel, Casper; Hyttel, Poul; Kurtzhals, Jørgen A L

    2014-07-01

    We hypothesized that the glycocalyx, which is important for endothelial integrity, is lost in severe malaria. C57BL/6 mice were infected with Plasmodium berghei ANKA, resulting in cerebral malaria, or P. chabaudi AS, resulting in uncomplicated malaria. We visualized the glycocalyx with transmission electron microscopy and measured circulating glycosaminoglycans by dot blot and ELISA. The glycocalyx was degraded in brain vasculature in cerebral and to a lesser degree uncomplicated malaria. It was affected on both intact and apoptotic endothelial cells. Circulating glycosaminoglycan levels suggested that glycocalyx disruption preceded cerebral manifestations. The contribution of this loss to pathogenesis should be studied further.

  11. Clinicopathological study of lymphocyte attachment to endothelial cells (endothelialitis) in various liver diseases.

    PubMed

    Nonomura, A; Mizukami, Y; Matsubara, F; Kobayashi, K

    1991-04-01

    An attachment of lymphocytes to the vascular wall, a feature called "endothelialitis" (ETL) or "endotheliitis", was investigated in various liver biopsies, including acute hepatitis (AH), hepatic infectious mononucleosis (IM), drug-induced hepatitis, alcoholic hepatitis and fibrosis, chronic persistent hepatitis (CPH), chronic active hepatitis (CAH), liver cirrhosis (LC), primary biliary cirrhosis (PBC), nonspecific reactive hepatitis (NSRH), and cases with a variety of diseases having almost normal liver histology as control material. Although ETL has been considered to be nearly pathognomic of graft-versus-host disease (GVHD) and acute transplant rejection, ETL was found in both portal and central veins with a variable incidence, not only in all categories of liver diseases, but also in the control group. The incidence of central vein ETL was significantly higher in AH, CAH, PBC, IM, alcoholic fibrosis, and NSRH than that of the control group, and that of portal vein ETL was significantly higher in AH, CPH, CAH, LC, PBC, IM, and alcoholic fibrosis. Even under the light microscope, lymphocytes attached to the endothelial cells had irregular cytoplasmic processes making contact with endothelial cells. Also lymphocytes located beneath the endothelial lining were frequently found. When ETL-positive and -negative cases in the same category were compared, the levels of serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) were usually higher in the ETL-positive group, and statistically significant differences were observed in CPH, CAH, LC, PBC and NSRH. In chronic hepatitis, the occurrence of portal vein ETL paralleled the histologic activity of portal inflammation, whereas central vein endothelialitis was associated with active parenchymal inflammation such as sinusoidal lymphocyte infiltration and spotty hepatocyte necrosis, indicating that ETL may be a phenomenon more frequently associated with active hepatic inflammation

  12. Endothelial progenitor cells: a new player in lupus?

    PubMed

    Haque, Sahena; Alexander, M Yvonne; Bruce, Ian N

    2012-01-01

    Patients with systemic lupus erythematosus (SLE) have a greatly increased risk of cardiovascular disease. There is growing interest in the link between vascular damage and lupus-specific inflammatory factors. Impaired endothelial repair could account for the endothelial dysfunction in this patient group. This review describes the contribution that endothelial progenitor cells could play in the pathogenesis of premature vascular damage in this disease. The methods of isolation, detection, and characterization of endothelial progenitor cells, together with their potential role in repair of the endothelium and as a therapeutic target in SLE, are discussed. PMID:22356717

  13. Cilostazol suppresses angiotensin II-induced apoptosis in endothelial cells.

    PubMed

    Shi, Miao-Qian; Su, Fei-Fei; Xu, Xuan; Liu, Xiong-Tao; Wang, Hong-Tao; Zhang, Wei; Li, Xue; Lian, Cheng; Zheng, Qiang-Sun; Feng, Zhi-Chun

    2016-03-01

    Patients with essential hypertension undergo endothelial dysfunction, particularly in the conduit arteries. Cilostazol, a type III phosphodiesterase inhibitor, serves a role in the inhibition of platelet aggregation and it is widely used in the treatment of peripheral vascular diseases. Previous studies have suggested that cilostazol suppresses endothelial dysfunction; however, it remains unknown whether cilostazol protects the endothelial function in essential hypertension. The aim of the present study was to investigate whether, and how, cilostazol suppresses angiotensin II (angII)‑induced endothelial dysfunction. Human umbilical vein endothelial cells (HUVECs) and Sprague Dawley rats were exposed to angII and treated with cilostazol. Endothelial cell apoptosis and function, nitric oxide and superoxide production, phosphorylation (p) of Akt, and caspase‑3 protein expression levels were investigated. AngII exposure resulted in the apoptosis of endothelial cells in vitro and in vivo. In vitro, cilostazol significantly suppressed the angII‑induced apoptosis of HUVECs; however, this effect was reduced in the presence of LY294002, a phosphoinositide 3 kinase (PI3K) inhibitor. Furthermore, cilostazol suppressed the angII‑induced p‑Akt downregulation and cleaved caspase‑3 upregulation. These effects were also alleviated by LY294002. In vivo, cilostazol suppressed the angII‑induced endothelial cell apoptosis and dysfunction. Cilostazol was also demonstrated to partially reduced the angII‑induced increase in superoxide production. The results of the present study suggested that cilostazol suppresses endothelial apoptosis and dysfunction by modulating the PI3K/Akt pathway.

  14. Mechanisms of endothelial dysfunction in obstructive sleep apnea.

    PubMed

    Atkeson, Amy; Jelic, Sanja

    2008-01-01

    Endothelial activation and inflammation are important mediators of accelerated atherogenesis and consequent increased cardiovascular morbidity in obstructive sleep apnea (OSA). Repetitive episodes of hypoxia/reoxygenation associated with transient cessation of breathing during sleep in OSA resemble ischemia/reperfusion injury and may be the main culprit underlying endothelial dysfunction in OSA. Additional factors such as repetitive arousals resulting in sleep fragmentation and deprivation and individual genetic susceptibility to vascular manifestations of OSA contribute to impaired endothelial function in OSA. The present review focuses on possible mechanisms that underlie endothelial activation and inflammation in OSA.

  15. Cilostazol suppresses angiotensin II-induced apoptosis in endothelial cells

    PubMed Central

    SHI, MIAO-QIAN; SU, FEI-FEI; XU, XUAN; LIU, XIONG-TAO; WANG, HONG-TAO; ZHANG, WEI; LI, XUE; LIAN, CHENG; ZHENG, QIANG-SUN; FENG, ZHI-CHUN

    2016-01-01

    Patients with essential hypertension undergo endothelial dysfunction, particularly in the conduit arteries. Cilostazol, a type III phosphodiesterase inhibitor, serves a role in the inhibition of platelet aggregation and it is widely used in the treatment of peripheral vascular diseases. Previous studies have suggested that cilostazol suppresses endothelial dysfunction; however, it remains unknown whether cilostazol protects the endothelial function in essential hypertension. The aim of the present study was to investigate whether, and how, cilostazol suppresses angiotensin II (angII)-induced endothelial dysfunction. Human umbilical vein endothelial cells (HUVECs) and Sprague Dawley rats were exposed to angII and treated with cilostazol. Endothelial cell apoptosis and function, nitric oxide and superoxide production, phosphorylation (p) of Akt, and caspase-3 protein expression levels were investigated. AngII exposure resulted in the apoptosis of endothelial cells in vitro and in vivo. In vitro, cilostazol significantly suppressed the angII-induced apoptosis of HUVECs; however, this effect was reduced in the presence of LY294002, a phosphoinositide 3 kinase (PI3K) inhibitor. Furthermore, cilostazol suppressed the angII-induced p-Akt downregulation and cleaved caspase-3 upregulation. These effects were also alleviated by LY294002. In vivo, cilostazol suppressed the angII-induced endothelial cell apoptosis and dysfunction. Cilostazol was also demonstrated to partially reduced the angII-induced increase in superoxide production. The results of the present study suggested that cilostazol suppresses endothelial apoptosis and dysfunction by modulating the PI3K/Akt pathway. PMID:26862035

  16. Eldecalcitol prevents endothelial dysfunction in postmenopausal osteoporosis model rats.

    PubMed

    Serizawa, Kenichi; Yogo, Kenji; Tashiro, Yoshihito; Takeda, Satoshi; Kawasaki, Ryohei; Aizawa, Ken; Endo, Koichi

    2016-02-01

    Postmenopausal women have high incidence of cardiovascular events as estrogen deficiency can cause endothelial dysfunction. Vitamin D is reported to be beneficial on endothelial function, but it remains controversial whether vitamin D is effective for endothelial dysfunction under the treatment for osteoporosis in postmenopausal women. The aim of this study was to evaluate the endothelial protective effect of eldecalcitol (ELD) in ovariectomized (OVX) rats. ELD (20  ng/kg) was orally administrated five times a week for 4 weeks from 1 day after surgery. After that, flow-mediated dilation (FMD) as an indicator of endothelial function was measured by high-resolution ultrasound in the femoral artery of living rats. ELD ameliorated the reduction of FMD in OVX rats. ELD inhibited the increase in NOX4, nitrotyrosine, and p65 and the decrease in dimer/monomer ratio of nitric oxide synthase in OVX rat femoral arteries. ELD also prevented the decrease in peroxisome proliferator-activated receptor gamma (PPARγ) in femoral arteries and cultured endothelial cells. Although PPARγ is known to inhibit osteoblastogenesis, ELD understandably increased bone mineral density of OVX rats without increase in PPARγ in bone marrow. These results suggest that ELD prevented the deterioration of endothelial function under condition of preventing bone loss in OVX rats. This endothelial protective effect of ELD might be exerted through improvement of endothelial nitric oxide synthase uncoupling, which is mediated by an antioxidative effect through normalization of vascular PPARγ/NF-κB signaling.

  17. Regulation of allergic lung inflammation by endothelial cell transglutaminase 2.

    PubMed

    Soveg, Frank; Abdala-Valencia, Hiam; Campbell, Jackson; Morales-Nebreda, Luisa; Mutlu, Gökhan M; Cook-Mills, Joan M

    2015-09-15

    Tissue transglutaminase 2 (TG2) is an enzyme with multiple functions, including catalysis of serotonin conjugation to proteins (serotonylation). Previous research indicates that TG2 expression is upregulated in human asthma and in the lung endothelium of ovalbumin (OVA)-challenged mice. It is not known whether endothelial cell TG2 is required for allergic inflammation. Therefore, to determine whether endothelial cell TG2 regulates allergic inflammation, mice with an endothelial cell-specific deletion of TG2 were generated, and these mice were sensitized and challenged in the airways with OVA. Deletion of TG2 in endothelial cells blocked OVA-induced serotonylation in lung endothelial cells, but not lung epithelial cells. Interestingly, deletion of endothelial TG2 reduced allergen-induced increases in respiratory system resistance, number of eosinophils in the bronchoalveolar lavage, and number of eosinophils in the lung tissue. Endothelial cell deletion of TG2 did not alter expression of adhesion molecules, cytokines, or chemokines that regulate leukocyte recruitment, consistent with other studies, demonstrating that deletion of endothelial cell signals does not alter lung cytokines and chemokines during allergic inflammation. Taken together, the data indicate that endothelial cell TG2 is required for allergic inflammation by regulating the recruitment of eosinophils into OVA-challenged lungs. In summary, TG2 functions as a critical signal for allergic lung responses. These data identify potential novel targets for intervention in allergy/asthma.

  18. Transcriptional Regulation oa Endothelial Cell And Vascular Development

    PubMed Central

    Park, Changwon; Kim, Tae Min; Malik, Asrar B.

    2013-01-01

    The establishment and maintenance of the vascular system is critical for embryonic development and postnatal life. Defects in endothelial cell development and vessel formation and function lead to embryonic lethality and are important in the etiology of vascular diseases. Here we review the underlying molecular mechanisms of endothelial cell differentiation, plasticity, and the development of the vasculature. This review focuses on the interplay among transcription factors and signaling molecules that specify the differentiation of vascular endothelial cells. We also discuss recent progress on reprogramming of somatic cells towards distinct endothelial cell lineages and its promise in regenerative vascular medicine. PMID:23661712

  19. Propofol ameliorates endothelial inflammation induced by hypoxia/reoxygenation in human umbilical vein endothelial cells: Role of phosphatase A2.

    PubMed

    Zhu, Minmin; Ding, Juan; Jiang, Hui; Kong, Lingchao; Sun, Zhirong; Chen, Jiawei; Miao, Changhong

    2015-10-01

    Hypoxia/reoxygenation (H/R) induces endothelial inflammation with augmentation of endothelial adhesion molecules over-expression. Propofol was reported to attenuate endothelial adhesion molecule expression in some situations. Here, we examined the molecular mechanism for how propofol restored H/R-mediated up-regulation of endothelial adhesion molecules in human umbilical vein endothelial cells (HUVECs). Compared with the control group, H/R up-regulated expression of Pin-1 and PP2A, increased p66(Shc)-Ser(36) phosphorylation, induced p66(Shc) mitochondrial translocation, O2(-) accumulation and NF-κB activation, and decreased eNOS-Ser(1177) phosphorylation and nitric oxide (NO) production, thus up-regulating expression of endothelial adhesion molecules and increasing mononuclear-endothelial interaction. More importantly, except that propofol had no effect on H/R-induced p66(Shc)-Ser(36) phosphorylation, most of H/R-mediated changes were alleviated by propofol, resulting in the reduction of endothelial adhesion molecules expression and mononuclear-endothelial adhesion. Moreover, we demonstrated the protective effect of propofol on H/R-induced endothelial inflammation was similar to that of calyculin A, an inhibitor of PP2A. In contrast, FTY720, an activator of PP2A, antagonized the effect of propofol. Our data indicated that propofol down-regulated PP2A expression, leading to reduced dephosphorylation of p66(Shc)-Ser(36) and eNOS-Ser(1177), which is associated with ROS accumulation and NO reduction, resulting in inhibition of endothelial adhesion molecule expression and mononuclear-endothelial interaction.

  20. Adherence of Candida to cultured vascular endothelial cells: mechanisms of attachment and endothelial cell penetration.

    PubMed

    Rotrosen, D; Edwards, J E; Gibson, T R; Moore, J C; Cohen, A H; Green, I

    1985-12-01

    To elucidate the pathogenesis of hematogenous Candida infections, we developed an in vitro model of Candida adherence to and penetration of human endothelial cells. We enhanced or inhibited adherence in order to probe mechanisms of attachment. Adherence of Candida albicans showed a linear relation to Candida inoculum (range, 10(2)-10(5) cfu, r = .99, P less than .01) and exceeded that of less virulent Candida species and that of Saccharomyces cerevisiae (P less than .01). Candida immune serum blocked attachment (greater than 95% inhibition; P less than .001), however, this activity was abolished by immunoprecipitation of immune serum with C. albicans mannan (P less than .001) and was unaffected by immunoprecipitation with S. cerevisiae mannan or by adsorption with particulate chitin. Adherence was diminished by exposing C. albicans to heat (greater than 99% inhibition; P less than .01), UV light (98% inhibition; P less than .01), or sodium periodate (greater than 72% inhibition; P less than .01). An extract from heat-exposed C. albicans blocked adherence (greater than 51% inhibition; P less than .001). Transmission electron microscopy demonstrated that viable or killed Candida organisms were attached to endothelial cells, were enveloped by membrane processes from the endothelial cell surface, and were incorporated into the endothelial cells within phagosomes. Cytochalasin B blocked incorporation without blocking surface attachment. PMID:3905987

  1. Loss of endothelial barrier integrity in mice with conditional ablation of podocalyxin (Podxl) in endothelial cells.

    PubMed

    Horrillo, Angélica; Porras, Gracia; Ayuso, Matilde S; González-Manchón, Consuelo

    2016-08-01

    Podocalyxin (Podxl) has an essential role in the development and function of the kidney glomerular filtration barrier. It is also expressed by vascular endothelia but perinatal lethality of podxl(-/-) mice has precluded understanding of its function in adult vascular endothelial cells (ECs). In this work, we show that conditional knockout mice with deletion of Podxl restricted to the vascular endothelium grow normally but most die spontaneously around three months of age. Histological analysis showed a nonspecific inflammatory infiltrate within the vessel wall frequently associated with degenerative changes, and involving vessels of different caliber in one or more organs. Podxl-deficient lung EC cultures exhibit increased permeability to dextran and macrophage transmigration. After thrombin stimulation, ECs lacking Podxl showed delayed recovery of VE-cadherin cell contacts, persistence of F-actin stress fibers, and sustained phosphorylation of the ERM complex and activation of RhoA, suggesting a failure in endothelial barrier stabilization. The results suggest that Podxl has an essential role in the regulation of endothelial permeability by influencing the mechanisms involved in the restoration of endothelial barrier integrity after injury. PMID:27289182

  2. Endothelial glycocalyx dysfunction in disease: albuminuria and increased microvascular permeability.

    PubMed

    Salmon, Andrew H J; Satchell, Simon C

    2012-03-01

    Appreciation of the glomerular microcirculation as a specialized microcirculatory bed, rather than as an entirely separate entity, affords important insights into both glomerular and systemic microvascular pathophysiology. In this review we compare regulation of permeability in systemic and glomerular microcirculations, focusing particularly on the role of the endothelial glycocalyx, and consider the implications for disease processes. The luminal surface of vascular endothelium throughout the body is covered with endothelial glycocalyx, comprising surface-anchored proteoglycans, supplemented with adsorbed soluble proteoglycans, glycosaminoglycans and plasma constituents. In both continuous and fenestrated microvessels, this endothelial glycocalyx provides resistance to the transcapillary escape of water and macromolecules, acting as an integral component of the multilayered barrier provided by the walls of these microvessels (ie acting in concert with clefts or fenestrae across endothelial cell layers, basement membranes and pericytes). Dysfunction of any of these capillary wall components, including the endothelial glycocalyx, can disrupt normal microvascular permeability. Because of its ubiquitous nature, damage to the endothelial glycocalyx alters the permeability of multiple capillary beds: in the glomerulus this is clinically apparent as albuminuria. Generalized damage to the endothelial glycocalyx can therefore manifest as both albuminuria and increased systemic microvascular permeability. This triad of altered endothelial glycocalyx, albuminuria and increased systemic microvascular permeability occurs in a number of important diseases, such as diabetes, with accumulating evidence for a similar phenomenon in ischaemia-reperfusion injury and infectious disease. The detection of albuminuria therefore has implications for the function of the microcirculation as a whole. The importance of the endothelial glycocalyx for other aspects of vascular function

  3. [Hypertension, endothelial dysfunction and cardiovascular risk].

    PubMed

    Nitenberg, A

    2006-10-01

    Increased blood pressure induces functional and structural changes of the vascular endothelium. Depression of endothelium-dependant vasodilatation is an early manifestation of endothelial dysfunction due to hypertension. It can be demonstrated by pharmacological or physiological tests. Decreased availability of nitric oxide (NO) is a major determinant of the depression of vasodilatation. It may be caused by a reduction in the activity of NO-endothelial synthase (NOSe) related to: 1) a deficit in substrate (L-arginine), 2) an inhibition by asymmetrical dimethylarginine, 3) a deficit in the cofactor tetrahydrobiopterin (BH4). However, the increase in oxidative stress, a producer of superoxide radicals which combine with NO to form peroxynitrates (ONOO-), is the determining factor. It is related to activation of membranous NAD(P)H oxidases initiated by the stimulation of activating mecanosensors of protein C kinase. The message is amplified by oxidation of BH4 which transforms the NOSe into a producer of superoxide radicals. A cascade of auto-amplification loops leading to atherosclerosis and its complications is then triggered. The superoxide radicals and the peroxynitrates oxidise the LDL-cholesterol. They activate the nuclear factor-kappaB which controls the genes stimulating the expression of many proteins: angiotensinogen and AT1 receptors which stimulate the sympathetic system, receptors of oxidised LDL, adhesion and migration factors (ICAM-1, VCAM-1, E-selectin and MCP-1), pro-inflammatory cytokins (interleukines and TNF-alpha), growth factors (MAP kinases), plasminogen activator inhibitor 1. The monocytes and smooth muscle cells produce metalloproteinases and pro-inflammatory cytokins which destabilise the atheromatous plaque and favourise vascular remodelling. Inshort, the endothelial dysfunction due to hypertension plays a role in a complex physiopathological process and is a marker of future cardiovascular events.

  4. Production of soluble Neprilysin by endothelial cells.

    PubMed

    Kuruppu, Sanjaya; Rajapakse, Niwanthi W; Minond, Dmitriy; Smith, A Ian

    2014-04-01

    A non-membrane bound form of Neprilysin (NEP) with catalytic activity has the potential to cleave substrates throughout the circulation, thus leading to systemic effects of NEP. We used the endothelial cell line Ea.hy926 to identify the possible role of exosomes and A Disintegrin and Metalloprotease 17 (ADAM-17) in the production of non-membrane bound NEP. Using a bradykinin based quenched fluorescent substrate (40 μM) assay, we determined the activity of recombinant human NEP (rhNEP; 12 ng), and NEP in the media of endothelial cells (10% v/v; after 24 h incubation with cells) to be 9.35±0.70 and 6.54±0.41 μmols of substrate cleaved over 3h, respectively. The presence of NEP in the media was also confirmed by Western blotting. At present there are no commercially available inhibitors specific for ADAM-17. We therefore synthesised two inhibitors TPI2155-14 and TPI2155-17, specific for ADAM-17 with IC50 values of 5.36 and 4.32 μM, respectively. Treatment of cells with TPI2155-14 (15 μM) and TPI2155-17 (4.3 μM) resulted in a significant decrease in NEP activity in media (62.37±1.43 and 38.30±4.70, respectively as a % of control; P<0.0001), implicating a possible role for ADAM-17 in NEP release. However, centrifuging media (100,000g for 1 h at 4 °C) removed all NEP activity from the supernatant indicating the likely role of exosomes in the release of NEP. Our data therefore indicated for the first time that NEP is released from endothelial cells via exosomes, and that this process is dependent on ADAM-17.

  5. Production of soluble Neprilysin by endothelial cells

    SciTech Connect

    Kuruppu, Sanjaya; Rajapakse, Niwanthi W.; Minond, Dmitriy; Smith, A. Ian

    2014-04-04

    Highlights: • A soluble full-length form of Neprilysin exists in media of endothelial cells. • Exosomal release is the key mechanism for the production of soluble Neprilysin. • Inhibition of ADAM-17 by specific inhibitors reduce Neprilysin release. • Exosome mediated release of Neprilysin is dependent on ADAM-17 activity. - Abstract: A non-membrane bound form of Neprilysin (NEP) with catalytic activity has the potential to cleave substrates throughout the circulation, thus leading to systemic effects of NEP. We used the endothelial cell line Ea.hy926 to identify the possible role of exosomes and A Disintegrin and Metalloprotease 17 (ADAM-17) in the production of non-membrane bound NEP. Using a bradykinin based quenched fluorescent substrate (40 μM) assay, we determined the activity of recombinant human NEP (rhNEP; 12 ng), and NEP in the media of endothelial cells (10% v/v; after 24 h incubation with cells) to be 9.35 ± 0.70 and 6.54 ± 0.41 μmols of substrate cleaved over 3 h, respectively. The presence of NEP in the media was also confirmed by Western blotting. At present there are no commercially available inhibitors specific for ADAM-17. We therefore synthesised two inhibitors TPI2155-14 and TPI2155-17, specific for ADAM-17 with IC{sub 50} values of 5.36 and 4.32 μM, respectively. Treatment of cells with TPI2155-14 (15 μM) and TPI2155-17 (4.3 μM) resulted in a significant decrease in NEP activity in media (62.37 ± 1.43 and 38.30 ± 4.70, respectively as a % of control; P < 0.0001), implicating a possible role for ADAM-17 in NEP release. However, centrifuging media (100,000g for 1 h at 4 °C) removed all NEP activity from the supernatant indicating the likely role of exosomes in the release of NEP. Our data therefore indicated for the first time that NEP is released from endothelial cells via exosomes, and that this process is dependent on ADAM-17.

  6. 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

  7. The female athlete triad and endothelial dysfunction.

    PubMed

    Lanser, Erica M; Zach, Karie N; Hoch, Anne Z

    2011-05-01

    A tremendous increase in the number of female athletes of all ages and abilities has occurred in the past 35 years. In general, sports and athletic competition produce healthier and happier women. However, explosion in participation has revealed clear gender-specific injuries and medical conditions unique to the female athlete. This article focuses on the latest advances in our knowledge of the female athlete triad and the relationship between athletic-associated amenorrhea and endothelial dysfunction. Treatment of vascular dysfunction with folic acid is also discussed. PMID:21570034

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

    PubMed

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

    2016-08-01

    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

  9. Endothelial juxtaposition of distinct adult stem cells activates angiogenesis signaling molecules in endothelial cells.

    PubMed

    Mohammadi, Elham; Nassiri, Seyed Mahdi; Rahbarghazi, Reza; Siavashi, Vahid; Araghi, Atefeh

    2015-12-01

    Efficacy of therapeutic angiogenesis needs a comprehensive understanding of endothelial cell (EC) function and biological factors and cells that interplay with ECs. Stem cells are considered the key components of pro- and anti-angiogenic milieu in a wide variety of physiopathological states, and interactions of EC-stem cells have been the subject of controversy in recent years. In this study, the potential effects of three tissue-specific adult stem cells, namely rat marrow-derived mesenchymal stem cells (rBMSCs), rat adipose-derived stem cells (rADSCs) and rat muscle-derived satellite cells (rSCs), on the endothelial activation of key angiogenic signaling molecules, including VEGF, Ang-2, VEGFR-2, Tie-2, and Tie2-pho, were investigated. Human umbilical vein endothelial cells (HUVECs) and rat lung microvascular endothelial cells (RLMECs) were cocultured with the stem cells or incubated with the stem cell-derived conditioned media on Matrigel. Following HUVEC-stem cell coculture, CD31-positive ECs were flow sorted and subjected to western blotting to analyze potential changes in the expression of the pro-angiogenic signaling molecules. Elongation and co-alignment of the stem cells were seen along the EC tubes in the EC-stem cell cocultures on Matrigel, with cell-to-cell dye communication in the EC-rBMSC cocultures. Moreover, rBMSCs and rADSCs significantly improved endothelial tubulogenesis in both juxtacrine and paracrine manners. These two latter stem cells dynamically up-regulated VEGF, Ang-2, VREGR-2, and Tie-2 but down-regulated Tie2-pho and the Tie2-pho/Tie-2 ratio in HUVECs. Induction of pro-angiogenic signaling in ECs by marrow- and adipose-derived MSCs further indicates the significance of stem cell milieu in angiogenesis dynamics. PMID:26068799

  10. Vascular endothelial growth factor signalling in endothelial cell survival: A role for NF{kappa}B

    SciTech Connect

    Grosjean, Jennifer . E-mail: Jennifer.grosjean@imperial.ac.uk; Kiriakidis, Serafim; Reilly, Kerri; Feldmann, Marc; Paleolog, Ewa

    2006-02-17

    Angiogenesis is the development of blood capillaries from pre-existing vessels. Vascular endothelial growth factor (VEGF) is a key regulator of vessel growth and regression, and acts as an endothelial survival factor by protecting endothelial cells from apoptosis. Many genes involved in cell proliferation and apoptosis are regulated by the nuclear factor kappa B (NF{kappa}B) transcription factor family. This study aimed to address the hypothesis that VEGF-mediated survival effects on endothelium involve NF{kappa}B. Using an NF{kappa}B-luciferase reporter adenovirus, we observed activation of NF{kappa}B following VEGF treatment of human umbilical vein endothelial cells. This was confirmed using electrophoretic mobility shift assay and found to involve nuclear translocation of NF{kappa}B sub-unit p65. However, NF{kappa}B activation occurred without degradation of inhibitory I{kappa}B proteins (I{kappa}B{alpha}, I{kappa}B{beta}, and I{kappa}B{epsilon}). Instead, tyrosine phosphorylation of I{kappa}B{alpha} was observed following VEGF treatment, suggesting NF{kappa}B activation was mediated by degradation-independent dissociation of I{kappa}B{alpha} from NF{kappa}B. Adenovirus-mediated over-expression of either native I{kappa}B{alpha}, or of I{kappa}B{alpha} in which tyrosine residue 42 was mutated to phenylalanine, inhibited induction of NF{kappa}B-dependent luciferase activity in response to VEGF. Furthermore, VEGF-induced upregulation of mRNA for the anti-apoptotic protein Bcl-2 and cell survival following serum withdrawal was reduced following I{kappa}B{alpha} over-expression. This study highlights that different molecular mechanisms of NF{kappa}B activation may be involved downstream of stimuli which activate the endothelial lining of blood vessels.

  11. Metformin improves endothelial function in aortic tissue and microvascular endothelial cells subjected to diabetic hyperglycaemic conditions.

    PubMed

    Ghosh, Suparna; Lakshmanan, Arun P; Hwang, Mu Ji; Kubba, Haidar; Mushannen, Ahmed; Triggle, Chris R; Ding, Hong

    2015-12-01

    The cellular mechanisms whereby metformin, the first line drug for type 2 diabetes (T2DM), mediates its antidiabetic effects remain elusive, particularly as to whether metformin has a direct protective action on the vasculature. This study was designed to determine if a brief 3-h exposure to metformin protects endothelial function against the effects of hyperglycaemia. We investigated the protective effects of metformin on endothelial-dependent vasodilatation (EDV) in thoracic aortae from T2DM db/db mice and on high glucose (HG, 40 mM) induced changes in endothelial nitric oxide synthase (eNOS) signaling in mouse microvascular endothelial cells (MMECs) in culture. Exposure of aortae from db+/? non-diabetic control mice to high glucose (HG, 40 mM) containing Krebs for 3-h significantly (P<0.05) reduced acetylcholine (ACh)-induced EDV compared to ACh-induced EDV in aortae maintained in normal glucose (NG, 11 mM) Krebs. The reduction of EDV was partially reversed following a 3-h exposure to 50 μM metformin; metformin also improved ACh-induced EDV in aortae from diabetic db/db mice. Immunoblot analysis of MMECs cultured in HG versus NG revealed a significant reduction of the ratio of phosphorylated (p-eNOS)/eNOS and p-Akt/Akt, but not the expression of total eNOS or Akt. The 3-h exposure of MMECs to metformin significantly (P<0.05) reversed the HG-induced reduction in phosphorylation of both eNOS and Akt; however, no changes were detected for phosphorylation of AMPK or the expression of SIRT1. Our data indicate that a 3-h exposure to metformin can reverse/reduce the impact of HG on endothelial function, via mechanisms linked to increased phosphorylation of eNOS and Akt.

  12. Effect of fat and carbohydrate consumption on endothelial function.

    PubMed

    Ong, P J; Dean, T S; Hayward, C S; Della Monica, P L; Sanders, T A; Collins, P

    Consumption of a meal high in monounsaturated fat was associated with acute impairment of endothelial function when compared with a carbohydrate-rich meal. Such a divergent response in endothelial function may be important in the modulation of vascular function in health and disease.

  13. Ionizing Radiation-Induced Endothelial Cell Senescence and Cardiovascular Diseases

    PubMed Central

    Wang, Yingying; Boerma, Marjan; Zhou, Daohong

    2016-01-01

    Exposure to ionizing radiation induces not only apoptosis but also senescence. While the role of endothelial cell apoptosis in mediating radiation-induced acute tissue injury has been extensively studied, little is known about the role of endothelial cell senescence in the pathogenesis of radiation-induced late effects. Senescent endothelial cells exhibit decreased production of nitric oxide and expression of thrombomodulin, increased expression of adhesion molecules, elevated production of reactive oxygen species and inflammatory cytokines and an inability to proliferate and form capillary-like structures in vitro. These findings suggest that endothelial cell senescence can lead to endothelial dysfunction by dysregulation of vasodilation and hemostasis, induction of oxidative stress and inflammation and inhibition of angiogenesis, which can potentially contribute to radiation-induced late effects such as cardiovascular diseases (CVDs). In this article, we discuss the mechanisms by which radiation induces endothelial cell senescence, the roles of endothelial cell senescence in radiation-induced CVDs and potential strategies to prevent, mitigate and treat radiation-induced CVDs by targeting senescent endothelial cells. PMID:27387862

  14. Endothelial-to-mesenchymal transition drives atherosclerosis progression

    PubMed Central

    Chen, Pei-Yu; Qin, Lingfeng; Baeyens, Nicolas; Li, Guangxin; Afolabi, Titilayo; Budatha, Madhusudhan; Tellides, George; Schwartz, Martin A.; Simons, Michael

    2015-01-01

    The molecular mechanisms responsible for the development and progression of atherosclerotic lesions have not been fully established. Here, we investigated the role played by endothelial-to-mesenchymal transition (EndMT) and its key regulator FGF receptor 1 (FGFR1) in atherosclerosis. In cultured human endothelial cells, both inflammatory cytokines and oscillatory shear stress reduced endothelial FGFR1 expression and activated TGF-β signaling. We further explored the link between disrupted FGF endothelial signaling and progression of atherosclerosis by introducing endothelial-specific deletion of FGF receptor substrate 2 α (Frs2a) in atherosclerotic (Apoe–/–) mice. When placed on a high-fat diet, these double-knockout mice developed atherosclerosis at a much earlier time point compared with that their Apoe–/– counterparts, eventually demonstrating an 84% increase in total plaque burden. Moreover, these animals exhibited extensive development of EndMT, deposition of fibronectin, and increased neointima formation. Additionally, we conducted a molecular and morphometric examination of left main coronary arteries from 43 patients with various levels of coronary disease to assess the clinical relevance of these findings. The extent of coronary atherosclerosis in this patient set strongly correlated with loss of endothelial FGFR1 expression, activation of endothelial TGF-β signaling, and the extent of EndMT. These data demonstrate a link between loss of protective endothelial FGFR signaling, development of EndMT, and progression of atherosclerosis. PMID:26517696

  15. Endothelial dysfunction as a potential contributor in diabetic nephropathy

    PubMed Central

    Nakagawa, Takahiko; Tanabe, Katsuyuki; Croker, Byron P.; Johnson, Richard J.; Grant, Maria B.; Kosugi, Tomoki; Li, Qiuhong

    2013-01-01

    The mechanisms that drive the development of diabetic nephropathy remain undetermined. Only 30–40% of patients with diabetes mellitus develop overt nephropathy, which suggests that other contributing factors besides the diabetic state are required for the progression of diabetic nephropathy. Endothelial dysfunction is associated with human diabetic nephropathy and retinopathy, and advanced diabetic glomerulopathy often exhibits thrombotic microangiopathy, including glomerular capillary microaneurysms and mesangiolysis, which are typical manifestations of endothelial dysfunction in the glomerulus. Likewise, diabetic mice with severe endothelial dysfunction owing to deficiency of endothelial nitric oxide synthase develop progressive nephropathy and retinopathy similar to the advanced lesions observed in humans with diabetes mellitus. Additionally, inhibitors of the renin–angiotensin system fail to be renoprotective in some individuals with diabetic nephropathy (due in part to aldosterone breakthrough) and in some mouse models of the disease. In this Review, we discuss the clinical and experimental evidence that supports a role for endothelial nitric oxide deficiency and subsequent endothelial dysfunction in the progression of diabetic nephropathy and retinopathy. If endothelial dysfunction is the key factor required for diabetic nephropathy, then agents that improve endothelial function or raise intraglomerular nitric oxide level could be beneficial in the treatment of diabetic nephropathy. PMID:21045790

  16. Cellular and molecular biology of aging endothelial cells.

    PubMed

    Donato, Anthony J; Morgan, R Garrett; Walker, Ashley E; Lesniewski, Lisa A

    2015-12-01

    Cardiovascular disease (CVD) is the leading cause of death in the United States and aging is a major risk factor for CVD development. One of the major age-related arterial phenotypes thought to be responsible for the development of CVD in older adults is endothelial dysfunction. Endothelial function is modulated by traditional CVD risk factors in young adults, but advancing age is independently associated with the development of vascular endothelial dysfunction. This endothelial dysfunction results from a reduction in nitric oxide bioavailability downstream of endothelial oxidative stress and inflammation that can be further modulated by traditional CVD risk factors in older adults. Greater endothelial oxidative stress with aging is a result of augmented production from the intracellular enzymes NADPH oxidase and uncoupled eNOS, as well as from mitochondrial respiration in the absence of appropriate increases in antioxidant defenses as regulated by relevant transcription factors, such as FOXO. Interestingly, it appears that NFkB, a critical inflammatory transcription factor, is sensitive to this age-related endothelial redox change and its activation induces transcription of pro-inflammatory cytokines that can further suppress endothelial function, thus creating a vicious feed-forward cycle. This review will discuss the two macro-mechanistic processes, oxidative stress and inflammation, that contribute to endothelial dysfunction with advancing age as well as the cellular and molecular events that lead to the vicious cycle of inflammation and oxidative stress in the aged endothelium. Other potential mediators of this pro-inflammatory endothelial phenotype are increases in immune or senescent cells in the vasculature. Of note, genomic instability, telomere dysfunction or DNA damage has been shown to trigger cell senescence via the p53/p21 pathway and result in increased inflammatory signaling in arteries from older adults. This review will discuss the current state

  17. Diagnosis and Management of Iridocorneal Endothelial Syndrome.

    PubMed

    Sacchetti, Marta; Mantelli, Flavio; Marenco, Marco; Macchi, Ilaria; Ambrosio, Oriella; Rama, Paolo

    2015-01-01

    The iridocorneal endothelial (ICE) syndrome is a rare ocular disorder that includes a group of conditions characterized by structural and proliferative abnormalities of the corneal endothelium, the anterior chamber angle, and the iris. Common clinical features include corneal edema, secondary glaucoma, iris atrophy, and pupillary anomalies, ranging from distortion to polycoria. The main subtypes of this syndrome are the progressive iris atrophy, the Cogan-Reese syndrome, and the Chandler syndrome. ICE syndrome is usually diagnosed in women in the adult age. Clinical history and complete eye examination including tonometry and gonioscopy are necessary to reach a diagnosis. Imaging techniques, such as in vivo confocal microscopy and ultrasound biomicroscopy, are used to confirm the diagnosis by revealing the presence of "ICE-cells" on the corneal endothelium and the structural changes of the anterior chamber angle. An early diagnosis is helpful to better manage the most challenging complications such as secondary glaucoma and corneal edema. Treatment of ICE-related glaucoma often requires glaucoma filtering surgery with antifibrotic agents and the use of glaucoma drainage implants should be considered early in the management of these patients. Visual impairment and pain associated with corneal edema can be successfully managed with endothelial keratoplasty.

  18. Endothelial Cell Dynamics during Anastomosis in vitro

    PubMed Central

    Diaz-Santana, Anthony; Shan, Mengrou; Stroock, Abraham D.

    2015-01-01

    Vascular anastomosis –the fusion of vessels from two distinct branches of the vascular system – represents a critical step in vascular growth under both healthy and pathological conditions, in vivo, and presents an important target for engineering of vascularized tissues, in vitro. Recent works in animal models have advanced our understanding of the molecular and cellular players in vascular anastomosis, but questions remain related to cellular dynamics and control of this process, in vitro. In this study, we exploited a three-dimensional (3-D) culture platform to examine the dynamics of endothelial cell (EC) during and after vascular anastomosis by allowing angiogenesis and vasculogenesis to proceed in parallel. We show that anastomosis occurs between sprouts formed by angiogenesis from an endothelium and tubes formed by vasculogenesis in the bulk of a 3-D matrix. This fusion leads to highly connected vessels that span from the surface of the matrix into the bulk in a manner that depends on cell density and identity. Further, we observe and analyze intermixing of endothelial cells of distinct origin (surface versus bulk) within the vessels structures that are formed; we provide evidence that the cells migrate along pre-existing vessels segments as part of this intermixing process. We conclude that anastomosis can occur between vessels emerging by angiogenesis and vasculogenesis and that this process may play an important role in contexts such as wound healing. PMID:25790315

  19. Endothelial Cellular Responses to Biodegradable Metal Zinc

    PubMed Central

    Ma, Jun; Zhao, Nan; Zhu, Donghui

    2016-01-01

    Biodegradable zinc (Zn) metals, a new generation of biomaterials, have attracted much attention due to their excellent biodegradability, bioabsorbability, and adaptability to tissue regeneration. Compared with magnesium (Mg) and iron (Fe), Zn exhibits better corrosion and mechanical behaviors in orthopedic and stent applications. After implantation, Zn containing material will slowly degrade, and Zn ions (Zn2+) will be released to the surrounding tissue. For stent applications, the local Zn2+concentration near endothelial tissue/cells could be high. However, it is unclear how endothelia will respond to such high concentrations of Zn2+, which is pivotal to vascular remodeling and regeneration. Here, we evaluated the short-term cellular behaviors of primary human coronary artery endothelial cells (HCECs) exposed to a concentration gradient (0−140 μM) of extracellular Zn2+. Zn2+ had an interesting biphasic effect on cell viability, proliferation, spreading, and migration. Generally, low concentrations of Zn2+ promoted viability, proliferation, adhesion, and migration, while high concentrations of Zn2+ had opposite effects. For gene expression profiles, the most affected functional genes were related to cell adhesion, cell injury, cell growth, angiogenesis, inflammation, vessel tone, and coagulation. These results provide helpful information and guidance for Zn-based alloy design as well as the controlled release of Zn2+in stent and other related medical applications. PMID:27689136

  20. Arsenic, reactive oxygen, and endothelial dysfunction.

    PubMed

    Ellinsworth, David C

    2015-06-01

    Human exposure to drinking water contaminated with arsenic is a serious global health concern and predisposes to cardiovascular disease states, such as hypertension, atherosclerosis, and microvascular disease. The most sensitive target of arsenic toxicity in the vasculature is the endothelium, and incubation of these cells with low concentrations of arsenite, a naturally occurring and highly toxic inorganic form of arsenic, rapidly induces reactive oxygen species (ROS) formation via activation of a specific NADPH oxidase (Nox2). Arsenite also induces ROS accumulation in vascular smooth muscle cells, but this is relatively delayed because, depending on the vessel from which they originate, these cells often lack Nox2 and/or its essential regulatory cytosolic subunits. The net effect of such activity is attenuation of endothelium-dependent conduit artery dilation via superoxide anion-mediated scavenging of nitric oxide (NO) and inhibition and downregulation of endothelial NO synthase, events that are temporally matched to the accumulation of oxidants across the vessel wall. By contrast, ROS induced by the more toxic organic trivalent arsenic metabolites (monomethylarsonous and dimethylarsinous acids) may originate from sources other than Nox2. As such, the mechanisms through which vascular oxidative stress develops in vivo under continuous exposure to all three of these potent arsenicals are unknown. This review is a comprehensive analysis of the mechanisms that mediate arsenic effects associated with Nox2 activation, ROS activity, and endothelial dysfunction, and also considers future avenues of research into what is a relatively poorly understood topic with major implications for human health.

  1. Morphological study of endothelial cells during freezing

    NASA Astrophysics Data System (ADS)

    Zhang, A.; Xu, L. X.; Sandison, G. A.; Cheng, S.

    2006-12-01

    Microvascular injury is recognized as a major tissue damage mechanism of ablative cryosurgery. Endothelial cells lining the vessel wall are thought to be the initial target of freezing. However, details of this injury mechanism are not yet completely understood. In this study, ECMatrix™ 625 was used to mimic the tumour environment and to allow the endothelial cells cultured in vitro to form the tube-like structure of the vasculature. The influence of water dehydration on the integrity of this structure was investigated. It was found that the initial cell shape change was mainly controlled by water dehydration, dependent on the cooling rate, resulting in the shrinkage of cells in the direction normal to the free surface. As the cooling was prolonged and temperature was lowered, further cell shape change could be induced by the chilling effects on intracellular proteins, and focal adhesions to the basement membrane. Quantitative analysis showed that the freezing induced dehydration greatly enhanced the cell surface stresses, especially in the axial direction. This could be one of the major causes of the final breaking of the cell junction and cell detachment.

  2. The involvement of endothelial mediators in leprosy

    PubMed Central

    Nogueira, Maria Renata Sales; Latini, Ana Carla Pereira; Nogueira, Maria Esther Salles

    2016-01-01

    Leprosy is a chronic infectious disease that requires better understanding since it continues to be a significant health problem in many parts of the world. Leprosy reactions are acute inflammatory episodes regarded as the central etiology of nerve damage in the disease. The activation of endothelium is a relevant phenomenon to be investigated in leprosy reactions. The present study evaluated the expression of endothelial factors in skin lesions and serum samples of leprosy patients. Immunohistochemical analysis of skin samples and serum measurements of VCAM-1, VEGF, tissue factor and thrombomodulin were performed in 77 leprosy patients and 12 controls. We observed significant increase of VCAM-1 circulating levels in non-reactional leprosy (p = 0.0009). The immunostaining of VEGF and tissue factor was higher in endothelium of non-reactional leprosy (p = 0.02 for both) than healthy controls. Patients with type 1 reaction presented increased thrombomodulin serum levels, compared with non-reactional leprosy (p = 0.02). In type 2 reaction, no significant modifications were observed for the endothelial factors investigated. The anti-inflammatory and antimicrobial activities of the endotfhelial factors may play key-roles in the pathogenesis of leprosy and should be enrolled in studies focusing on alternative targets to improve the management of leprosy and its reactions. PMID:27706378

  3. 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.

  4. Endothelial Cellular Responses to Biodegradable Metal Zinc

    PubMed Central

    Ma, Jun; Zhao, Nan; Zhu, Donghui

    2016-01-01

    Biodegradable zinc (Zn) metals, a new generation of biomaterials, have attracted much attention due to their excellent biodegradability, bioabsorbability, and adaptability to tissue regeneration. Compared with magnesium (Mg) and iron (Fe), Zn exhibits better corrosion and mechanical behaviors in orthopedic and stent applications. After implantation, Zn containing material will slowly degrade, and Zn ions (Zn2+) will be released to the surrounding tissue. For stent applications, the local Zn2+concentration near endothelial tissue/cells could be high. However, it is unclear how endothelia will respond to such high concentrations of Zn2+, which is pivotal to vascular remodeling and regeneration. Here, we evaluated the short-term cellular behaviors of primary human coronary artery endothelial cells (HCECs) exposed to a concentration gradient (0−140 μM) of extracellular Zn2+. Zn2+ had an interesting biphasic effect on cell viability, proliferation, spreading, and migration. Generally, low concentrations of Zn2+ promoted viability, proliferation, adhesion, and migration, while high concentrations of Zn2+ had opposite effects. For gene expression profiles, the most affected functional genes were related to cell adhesion, cell injury, cell growth, angiogenesis, inflammation, vessel tone, and coagulation. These results provide helpful information and guidance for Zn-based alloy design as well as the controlled release of Zn2+in stent and other related medical applications.

  5. Simulated microgravity upregulates an endothelial vasoconstrictor prostaglandin

    NASA Technical Reports Server (NTRS)

    Sangha, D. S.; Han, S.; Purdy, R. E.

    2001-01-01

    Endothelial nitric oxide contributes to the vascular hyporesponsiveness to norepinephrine (NE) observed in carotid arteries from rats exposed to simulated microgravity. The goal of the present study was to determine whether a cyclooxygenase product of arachidonic acid also influences vascular responsiveness in this setting. Microgravity was simulated in rats by hindlimb unweighting (HU). After 20 days of HU, carotid arteries were isolated from control and HU-treated rats, and vascular rings were mounted in tissue baths for the measurement of isometric contraction. Two cyclooxygenase inhibitors, indomethacin and ibuprofen, and the selective thromboxane A(2) prostanoid-receptor antagonist, SQ-29548, had no effect on the contraction to NE in control vessels but markedly reduced contraction to NE in HU vessels. When the endothelium was removed, indomethacin no longer had any effect on the NE-induced contraction in HU vessels. In endothelium-intact vessels in the presence of indomethacin, the addition of the nitric oxide synthase inhibitor, N(G)-L-nitro-arginine methyl ester, to the medium bathing HU vessels increased the contraction to NE to the level of that of the control vessels. These results indicate that HU treatment induced two endothelial changes in carotid artery that opposed each other. Nitric oxide activity was increased and was responsible for the vascular hyporesponsiveness to NE. The activity of a vasoconstrictor prostaglandin was also increased, and attenuated the vasodilating effect of nitric oxide.

  6. Endothelial cell permeability to water and antipyrine

    SciTech Connect

    Garrick, R.A.

    1986-03-05

    The endothelium provides a structural barrier between plasma constituents and the tissues. The permeability characteristics of the the endothelial cells regulate the transcellular movement of materials across this barrier while other movement is paracellular. In this study the permeability of the endothelial cells to tritiated water (/sup 3/HHO) and /sup 14/C-labeled antipyrine (AP) was investigated. The cells were isolated non-enzymatically from calf pulmonary artery and were maintained in culture and used between the seventh and fifteenth passage. The cells were removed from the T-flasks with a rubber policeman, titurated with a 22g needle and centrifuged. The cells were mixed with an extracellular marker, drawn into polyethylene tubing and packed by centrifugation for use in the linear diffusion technique. All measurements were made at 37 C. The diffusion coefficients for /sup 3/HHO through the packed cells (D), the intracellular material (D/sub 2/), and the extracellular material (D/sub 1/) were 0.682, 0.932 and 2.45 x 10/sup -5/ cm/sup 2/ s/sup -1/ and for AP were 0.273, 0.355 and 1.13 x 10/sup -5/ cm/sup 2/ s/sup -1/ respectively. The permeability coefficient calculated by the series-parallel pathway model for /sup 3/HHO was higher than that for AP and for both /sup 3/HHO and AP were lower than those calculated for isolated lung cells and erythrocytes.

  7. Arsenic, reactive oxygen, and endothelial dysfunction.

    PubMed

    Ellinsworth, David C

    2015-06-01

    Human exposure to drinking water contaminated with arsenic is a serious global health concern and predisposes to cardiovascular disease states, such as hypertension, atherosclerosis, and microvascular disease. The most sensitive target of arsenic toxicity in the vasculature is the endothelium, and incubation of these cells with low concentrations of arsenite, a naturally occurring and highly toxic inorganic form of arsenic, rapidly induces reactive oxygen species (ROS) formation via activation of a specific NADPH oxidase (Nox2). Arsenite also induces ROS accumulation in vascular smooth muscle cells, but this is relatively delayed because, depending on the vessel from which they originate, these cells often lack Nox2 and/or its essential regulatory cytosolic subunits. The net effect of such activity is attenuation of endothelium-dependent conduit artery dilation via superoxide anion-mediated scavenging of nitric oxide (NO) and inhibition and downregulation of endothelial NO synthase, events that are temporally matched to the accumulation of oxidants across the vessel wall. By contrast, ROS induced by the more toxic organic trivalent arsenic metabolites (monomethylarsonous and dimethylarsinous acids) may originate from sources other than Nox2. As such, the mechanisms through which vascular oxidative stress develops in vivo under continuous exposure to all three of these potent arsenicals are unknown. This review is a comprehensive analysis of the mechanisms that mediate arsenic effects associated with Nox2 activation, ROS activity, and endothelial dysfunction, and also considers future avenues of research into what is a relatively poorly understood topic with major implications for human health. PMID:25788710

  8. On-chip endothelial inflammatory phenotyping.

    PubMed

    DeVerse, J Sherrod; Bailey, Keith A; Foster, Greg A; Mittal, Vaishali; Altman, Stuart M; Simon, Scott I; Passerini, Anthony G

    2012-07-21

    Atherogenesis is potentiated by metabolic abnormalities that contribute to a heightened state of systemic inflammation resulting in endothelial dysfunction. However, early functional changes in endothelium that signify an individual's level of risk are not directly assessed clinically to help guide therapeutic strategy. Moreover, the regulation of inflammation by local hemodynamics contributes to the non-random spatial distribution of atherosclerosis, but the mechanisms are difficult to delineate in vivo. We describe a lab-on-a-chip based approach to quantitatively assay metabolic perturbation of inflammatory events in human endothelial cells (EC) and monocytes under precise flow conditions. Standard methods of soft lithography are used to microfabricate vascular mimetic microfluidic chambers (VMMC), which are bound directly to cultured EC monolayers. These devices have the advantage of using small volumes of reagents while providing a platform for directly imaging the inflammatory events at the membrane of EC exposed to a well-defined shear field. We have successfully applied these devices to investigate cytokine-, lipid- and RAGE-induced inflammation in human aortic EC (HAEC). Here we document the use of the VMMC to assay monocytic cell (THP-1) rolling and arrest on HAEC monolayers that are conditioned under differential shear characteristics and activated by the inflammatory cytokine TNF-α. Studies such as these are providing mechanistic insight into atherosusceptibility under metabolic risk factors.

  9. Vascular Endothelial Growth Factor is a Secreted Angiogenic Mitogen

    NASA Astrophysics Data System (ADS)

    Leung, David W.; Cachianes, George; Kuang, Wun-Jing; Goeddel, David V.; Ferrara, Napoleone

    1989-12-01

    Vascular endothelial growth factor (VEGF) was purified from media conditioned by bovine pituitary folliculostellate cells (FC). VEGF is a heparin-binding growth factor specific for vascular endothelial cells that is able to induce angiogenesis in vivo. Complementary DNA clones for bovine and human VEGF were isolated from cDNA libraries prepared from FC and HL60 leukemia cells, respectively. These cDNAs encode hydrophilic proteins with sequences related to those of the A and B chains of platelet-derived growth factor. DNA sequencing suggests the existence of several molecular species of VEGF. VEGFs are secreted proteins, in contrast to other endothelial cell mitogens such as acidic or basic fibroblast growth factors and platelet-derived endothelial cell growth factor. Human 293 cells transfected with an expression vector containing a bovine or human VEGF cDNA insert secrete an endothelial cell mitogen that behaves like native VEGF.

  10. Impact of Hemorheological and Endothelial Factors on Microcirculation

    NASA Astrophysics Data System (ADS)

    Turchetti, Vera; Boschi, Letizia; Donati, Giovanni; Trabalzini, Luca; Forconi, Sandro

    Previous studies showed that endothelial alterations caused by physical stress worsened the hemorheological parameters mainly in patients affected by ischemic vascular diseases: major vascular alterations have been found in patients with very high endothelial dysfunction indexes: these indexes are given by the various substances produced by the endothelium, but it is very difficult to have a value which clearly identifies the real state of the endothelial alteration. The function of the NO, an endogenous vasodilator whose synthesis is catalyzed by NOs, can be determined by the Citrulline/Arginine ratio, which represents the level of activity of the enzyme. A very good index of the endothelial dysfunction is asymmetric dimethylarginine (ADMA), a powerful endogenous inhibitor of NOs; in fact several studies have demonstrated a strong relationship between ischemic vascular disease and high levels of plasmatic ADMA. Our recent studies on heart failure and on ischemic cerebrovascular diseases evaluate endothelial dysfunctions and hemorheological parameters.

  11. Transcriptional targeting of tumor endothelial cells for gene therapy

    PubMed Central

    Dong, Zhihong; Nör, Jacques E.

    2009-01-01

    It is well known that angiogenesis plays a critical role in the pathobiology of tumors. Recent clinical trials have shown that inhibition of angiogenesis can be an effective therapeutic strategy for patients with cancer. However, one of the outstanding issues in anti-angiogenic treatment for cancer is the development of toxicities related to off-target effects of drugs. Transcriptional targeting of tumor endothelial cells involves the use of specific promoters for selective expression of therapeutic genes in the endothelial cells lining the blood vessels of tumors. Recently, several genes that are expressed specifically in tumor-associated endothelial cells have been identified and characterized. These discoveries have enhanced the prospectus of transcriptionaly targeting tumor endothelial cells for cancer gene therapy. In this manuscript, we review the promoters, vectors, and therapeutic genes that have been used for transcriptional targeting of tumor endothelial cells, and discuss the prospects of such approaches for cancer gene therapy. PMID:19393703

  12. Constructive remodeling of a synthetic endothelial extracellular matrix

    PubMed Central

    Han, Sewoon; Shin, Yoojin; Jeong, Hyo Eun; Jeon, Jessie S.; Kamm, Roger D.; Huh, Dongeun; Sohn, Lydia L.; Chung, Seok

    2015-01-01

    The construction of well-controllable in vitro models of physiological and pathological vascular endothelium remains a fundamental challenge in tissue engineering and drug development. Here, we present an approach for forming a synthetic endothelial extracellular matrix (ECM) that closely resembles that of the native structure by locally depositing basement membrane materials onto type 1 collagen nanofibers only in a region adjacent to the endothelial cell (EC) monolayer. Culturing the EC monolayer on this synthetic endothelial ECM remarkably enhanced its physiological properties, reducing its vascular permeability, and promoting a stabilized, quiescent phenotype. We demonstrated that the EC monolayer on the synthetic endothelial ECM neither creates non-physiological barriers to cell-cell or cell-ECM interactions, nor hinders molecular diffusion of growth factors and other molecules. The synthetic endothelial ECM and vascular endothelium on it may help us enter in a new phase of research in which various models of the biological barrier behavior can be tested experimentally. PMID:26687334

  13. Treating Coronary Disease and the Impact of Endothelial Dysfunction

    PubMed Central

    Matsuzawa, Yasushi; Guddeti, Raviteja R.; Kwon, Taek-Geun; Lerman, Lilach O.; Lerman, Amir

    2014-01-01

    Ischemic heart disease is the leading cause of morbidity and mortality throughout the world. Many clinical trials have suggested that lifestyle and pharmacologic interventions are effective in attenuating atherosclerotic disease progression and events development. However, an individualized approach with careful consideration to comprehensive vascular health is necessary to perform successful intervention strategies. Endothelial dysfunction plays a pivotal role in the early stage of atherosclerosis and is also associated with plaque progression and occurrence of atherosclerotic complications. The assessment of endothelial function provides us with important information about individual patient risk, progress and vulnerability of disease, and guidance of therapy. Thus, the application of endothelial function assessment might enable clinicians to innovate ideal individualized medicine. In this review, we summarize the current knowledge on the impact of pharmacological therapies for atherosclerotic cardiovascular disease on endothelial dysfunction, and argue for the utility of non-invasive assessment of endothelial function aiming at individualized medicine. PMID:25459974

  14. Endothelial cell heterogeneity: antioxidant profiles determine vulnerability to oxidant injury.

    PubMed

    Vercellotti, G M; Dobson, M; Schorer, A E; Moldow, C F

    1988-02-01

    Human umbilical vein endothelial cells were more sensitive to hydrogen peroxide lysis than cow pulmonary artery endothelial cells. Conversely, activated neutrophils which utilize hydrogen peroxide-mediated cell cytotoxicity cell mechanisms were more toxic to the cow pulmonary artery cells. This discordance was not related to neutrophil adhesion to either cell type or cell passage number. The antioxidant profiles of the endothelial cells revealed that cow pulmonary artery cells were rich in catalase to consume bolus hydrogen peroxide presented to them, while human umbilical vein endothelial cells utilize glutathione peroxidase-linked mechanisms to detoxify a slower more sustained release of hydrogen peroxide generated by neutrophils. Endothelial cells from different species and sites may utilize diversified antioxidant protective mechanisms. PMID:3340627

  15. Hemostasis and endothelial damage during sepsis.

    PubMed

    Johansen, Maria Egede

    2015-08-01

    The sepsis syndrome represents a disease continuum, including severe sepsis and septic shock associated with high mortality. One of the main problems in severe sepsis and septic shock, resulting in organ failure and death, are disturbances in the hemostasis due to sepsis-related coagulopathy. Sepsis-related coagulopathy affects not only traditional coagulation factors, but also the platelets and endothelium. Functional testing of the hemostatic system has found application in critical illness. Thrombelastography (TEG) provides an overview of the hemostatic system allowing for an evaluation of interactions between coagulation factors and platelets. Additionally, the role of the endothelium during sepsis can be explored through testing of biomarkers of endothelial damage. The three studies comprising this PhD thesis all investigate important aspects of the disturbed hemostasis during sepsis, including endothelial damage. Together, the specific findings from the three studies improve the existing understanding of sepsis-related coagulopathy, and the possible influences of some of the treatments offered these patients. The first study investigates the occurrence of antimicrobial-induced thrombocytopenia among critically ill patients. In sepsis, thrombocytopenia is a predictor of poor outcome, and reports, of mainly casuistic nature, have previously hypothesized that specific antimicrobial agents could induce in sepsis-related thrombocytopenia. This hypothesis was tested using a randomized designed set-up, encompassing 1147 critically ill patients, and no significant difference in risk of thrombocytopenia was observed among patients receiving large amounts of antimicrobials vs. patients receiving standard-of-care. As a consequence, the risk of antimicrobial-induced thrombocytopenia in the general population of critically ill patients seemingly does not represent a substantial problem and thrombocytopenia during critical illness is most likely due to other factors such

  16. Propranolol treatment of infantile hemangioma endothelial cells: A molecular analysis.

    PubMed

    Stiles, Jessica; Amaya, Clarissa; Pham, Robert; Rowntree, Rebecca K; Lacaze, Mary; Mulne, Arlynn; Bischoff, Joyce; Kokta, Victor; Boucheron, Laura E; Mitchell, Dianne C; Bryan, Brad A

    2012-10-01

    Infantile hemangiomas (IHs) are non-malignant, largely cutaneous vascular tumors affecting approximately 5-10% of children to varying degrees. During the first year of life, these tumors are strongly proliferative, reaching an average size ranging from 2 to 20 cm. These lesions subsequently stabilize, undergo a spontaneous slow involution and are fully regressed by 5 to 10 years of age. Systemic treatment of infants with the non-selective β-adrenergic receptor blocker, propranolol, has demonstrated remarkable efficacy in reducing the size and appearance of IHs. However, the mechanism by which this occurs is largely unknown. In this study, we sought to understand the molecular mechanisms underlying the effectiveness of β blocker treatment in IHs. Our data reveal that propranolol treatment of IH endothelial cells, as well as a panel of normal primary endothelial cells, blocks endothelial cell proliferation, migration, and formation of the actin cytoskeleton coincident with alterations in vascular endothelial growth factor receptor-2 (VEGFR-2), p38 and cofilin signaling. Moreover, propranolol induces major alterations in the protein levels of key cyclins and cyclin-dependent kinase inhibitors, and modulates global gene expression patterns with a particular affect on genes involved in lipid/sterol metabolism, cell cycle regulation, angiogenesis and ubiquitination. Interestingly, the effects of propranolol were endothelial cell-type independent, affecting the properties of IH endothelial cells at similar levels to that observed in neonatal dermal microvascular and coronary artery endothelial cells. This data suggests that while propranolol markedly inhibits hemangioma and normal endothelial cell function, its lack of endothelial cell specificity hints that the efficacy of this drug in the treatment of IHs may be more complex than simply blockage of endothelial function as previously believed.

  17. Endothelial cells modulate renin secretion from isolated mouse juxtaglomerular cells.

    PubMed Central

    Kurtz, A; Kaissling, B; Busse, R; Baier, W

    1991-01-01

    Utilizing cocultures of mouse renal juxtaglomerular cells with bovine microvascular endothelial cells, we have examined whether endothelial cells exert direct influence on renin secretion from renal juxtaglomerular cells. In the presence of endothelial cells both spontaneous and forskolin (10 microM) or isoproterenol (10 microM) stimulated renin release were markedly attenuated. The stimulatory effect of the calmodulin antagonist calmidazolium (10 microM) on renin secretion was not altered by endothelial cells, whereas the stimulatory effect of ethylisopropylamiloride (50 microM) an inhibitor of sodium-proton exchange was enhanced in the presence of endothelial cells. Indomethacin (10 microM) and NG-monomethyl-l-arginine (NMMA) (1 mM) used to inhibit cyclooxygenase activity and production of endothelium-derived relaxing factor (EDRF) decreased spontaneous renin release in the presence of endothelial cells only, but had no effect on forskolin stimulated renin secretion. Endothelin (1 microM) inhibited cAMP stimulated renin release both in the absence and in the presence of endothelial cells. ATP (10 microM) which acts on both endothelial and juxtaglomerular cells via purinergic P2 receptors inhibited cAMP stimulated renin release only in the absence but not in the presence of endothelial cells. This modulatory effect of endothelial cells was no altered by indomethacin nor by NMMA. Taken together, our findings provide first evidence for a local control function of the endothelium on cAMP stimulated renin secretion from renal juxtaglomerular cells, which could in part be mediated by endothelin. Images PMID:1717509

  18. Transient disruptions of aortic endothelial cell plasma membranes.

    PubMed Central

    Yu, Q. C.; McNeil, P. L.

    1992-01-01

    Cells of gut, skin, and muscle frequently suffer transient survivable plasma membrane disruptions ("wounds") under physiological conditions, but it is not known whether endothelial cells of the aorta, which are constantly exposed to hemodynamically generated mechanical forces, similarly are injured in vivo. We have used serum albumin as a molecular probe for identifying endothelial cells of the rat aorta that incurred and survived transient plasma membrane wounds in vivo. Such wounded endothelial cells were in fact observed in the aortas of all rats examined. However, the percentage of wounded cells in the total aortic endothelial population varied remarkably between individuals ranging from 1.4% to 17.9% with a mean of 6.5% (+/- 4.6% SD). Wounded endothelial cells were heterogeneously distributed, being found in distinct clusters often in the shape of streaks aligned with the long axis of the vessel, or in the shape of partial or complete rims surrounding bifurcation openings, such as the ostia of the intercostal arteries. Physical exercise (running) did not increase the frequency of aortic endothelial cell membrane wounding, nor did spontaneous hypertension. Surprisingly, 80% of mitotic endothelial cell figures were identified as wounded. This article identified a previously unrecognized form of endothelial cell injury, survivable disruptions of the plasma membrane, and shows that injury to the endothelial cells of the normal aorta is far more commonplace than previously suspected. Plasma membrane wounding of endothelial cells could be linked to the initiation of atherosclerosis. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 11 Figure 6 Figure 8 PMID:1466399

  19. Endothelial nitric oxide: protector of a healthy mind.

    PubMed

    Katusic, Zvonimir S; Austin, Susan A

    2014-04-01

    Endothelial nitric oxide (NO) is generated by constitutively active endothelial nitric oxide synthase (eNOS), an essential enzyme responsible for cardiovascular homeostasis. Historically, endothelial NO was first recognized as a major vasodilator involved in control of vasomotor function and local blood flow. In this review, our attention is focused on the emerging role of endothelial NO in linking cerebrovascular function with cognition. We will discuss the recognized ability of endothelial NO to modulate processing of amyloid precursor protein (APP), influence functional status of microglia, and affect cognitive function. Existing evidence suggests that the loss of NO in cultured human cerebrovascular endothelium causes increased expression of APP and β-site APP-cleaving enzyme 1 (BACE1) thereby resulting in increased secretion of amyloid β peptides (Aβ1-40 and Aβ1-42). Furthermore, increased expression of APP and BACE1 as well as increased production of Aβ peptides was detected in the cerebral microvasculature and brain tissue of eNOS-deficient mice. Since Aβ peptides are considered major cytotoxic molecules responsible for the pathogenesis of Alzheimer's disease, these observations support the concept that a loss of endothelial NO might significantly contribute to the initiation and progression of cognitive decline. In addition, genetic inactivation of eNOS causes activation of microglia and promotes a pro-inflammatory phenotype in the brain. Behavioural analysis revealed that eNOS-deficient mice exhibit impaired cognitive performance thereby indicating that selective loss of endothelial NO has a detrimental effect on the function of neuronal cells. Together with findings from prior studies demonstrating the ability of endothelial NO to affect synaptic plasticity, mitochondrial biogenesis, and function of neuronal progenitor cells, it is becoming apparent that the role of endothelial NO in the control of central nervous system function is very complex. We

  20. Novel role of lactosylceramide in vascular endothelial growth factor-mediated angiogenesis in human endothelial cells.

    PubMed

    Rajesh, Mohanraj; Kolmakova, Antonina; Chatterjee, Subroto

    2005-10-14

    Vascular endothelial growth factor (VEGF) has been implicated in angiogenesis associated with coronary heart disease, vascular complications in diabetes, inflammatory vascular diseases, and tumor metastasis. The mechanism of VEGF-driven angiogenesis involving glycosphingolipids such as lactosylceramide (LacCer), however, is not known. To demonstrate the involvement of LacCer in VEGF-induced angiogenesis, we used small interfering RNA (siRNA)-mediated silencing of LacCer synthase expression (GalT-V) in human umbilical vein endothelial cells. This gene silencing markedly inhibited VEGF-induced platelet endothelial cell adhesion molecule-1 (PECAM-1) expression and angiogenesis. Second, we used D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), an inhibitor of LacCer synthase and glucosylceramide synthase, that significantly mitigated VEGF-induced PECAM-1 expression and angiogenesis. Interestingly, these phenotypic changes were reversed by LacCer but not by structurally related compounds such as glucosylceramide, digalactosylceramide, and ceramide. In a human mesothelioma cell line (REN) that lacks the endogenous expression of PECAM-1, VEGF/LacCer failed to stimulate PECAM-1 expression and tube formation/angiogenesis. In REN cells expressing human PECAM-1 gene/protein, however, both VEGF and LacCer-induced PECAM-1 protein expression and tube formation/angiogenesis. In fact, VEGF-induced but not LacCer-induced angiogenesis was mitigated by SU-1498, a VEGF receptor tyrosine kinase inhibitor. Also, VEGF/LacCer-induced PECAM-1 expression and angiogenesis was mitigated by protein kinase C and phospholipase A2 inhibitors. These results indicate that LacCer generated in VEGF-treated endothelial cells may serve as an important signaling molecule for PECAM-1 expression and in angiogenesis. This finding and the reagents developed in our report may be useful as anti-angiogenic drugs for further studies in vitro and in vivo. PMID:16151023

  1. Haemodynamical variables versus endothelial hormones in hypertensive and type 2 diabetic patients with endothelial dysfunction.

    PubMed

    Fouillioux, Christian; Contreras, Freddy; Lares, Mary; Magaldi, Luis; Velasco, Manuel; La Mayda, Claudia; Pacheco, Betsy; Rojas, Joselyn; Chacín, Maricarmen; Cano, Raquel; Gotera, Daniela; Bermúdez, Valmore

    2010-01-01

    Leptin is a 167 aminoacid peptidic hormone secreted by adipose tissue. It works mainly in the hypothalamus at thirst signal, but given its closed connections with inflammatory and endothelial systems, also has been postulated that it may exert a regulatory control over blood pressure (BP), interacting with nitric oxide (NO) and C reactive protein (CRP). The cold pressor test (CPT) is a simple test that indirectly determines endothelial dysfunction. In this work, biochemical indicators (CRP, leptin, and NO) and hemodynamic indicators (systolic and diastolic BP) were performed and evaluated in hypertensive, type 2 diabetic, and control subjects during a single CPT for assessment of endothelial dysfunction. A total of 43 subjects, males and females aged 25 to 60 years and divided in three groups, 15 healthy volunteers, 13 hypertensive patients, and 15 patients with type 2 diabetes, were included in the study. A complete clinical history was obtained from each subject, and a complete physical examination, including an electrocardiogram was carried out. During the assay of 30 minutes, 0.9% saline was infused intravenously. CPT was performed to assess the cardiovascular reactivity at minute 15. The cardiovascular variables (systolic and diastolic BP) were measured in minute 0, 16, and 30. In addition, serum variables were obtained at the beginning and at the end of the experiment, and statistical analysis was performed. CPT caused in all subjects a significant increase of BP and pulse. There were no significant differences to CPR and leptin in any group, although we observed significant differences for NO (P < 0.05). Sensitivity and specificity for all biochemical variables resulted in nonsignificant statistical or clinical importance as markers of endothelial dysfunction; however, a positive association was found when leptin and NO were evaluated together (sensitivity: 0.2; specificity. 0.8). CRP, leptin, and NO did not shown any direct and significant association with

  2. Tumor endothelial cells with distinct patterns of TGFβ-driven endothelial-to-mesenchymal transition

    PubMed Central

    Xiao, Lin; Kim, Dae Joong; Davis, Clayton L.; McCann, James V.; Dunleavey, James M.; Vanderlinden, Alissa; Xu, Nuo; Pattenden, Samantha G.; Frye, Stephen V.; Xu, Xia; Onaitis, Mark; Monaghan-Benson, Elizabeth; Burridge, Keith; Dudley, Andrew C.

    2015-01-01

    Endothelial-to-mesenchymal transition (EndMT) occurs during development and underlies the pathophysiology of multiple diseases. In tumors, unscheduled EndMT generates cancer-associated myofibroblasts that fuel inflammation and fibrosis, and may contribute to vascular dysfunction that promotes tumor progression. We report that freshly isolated subpopulations of tumor-specific endothelial cells (TEC) from a spontaneous mammary tumor model undergo distinct forms of EndMT in response to TGFβ stimulation. Whereas some TEC strikingly up-regulate alpha smooth muscle actin (SMA), a principal marker of EndMT and activated myofibroblasts, counterpart normal mammary gland endothelial cells (NEC) showed little change in SMA expression after TGFβ treatment. Compared with NEC, SMA+ TEC were 40 % less motile in wound healing assays and formed more stable vascular-like networks in vitro when challenged with TGFβ. Lineage tracing using ZsGreenCdh5-Cre reporter mice confirmed that only a fraction of vessels in breast tumors contain SMA+ TEC, suggesting that not all endothelial cells (EC) respond identically to TGFβ in vivo. Indeed, examination of 84 TGFβ-regulated target genes revealed entirely different genetic signatures in TGFβ-stimulated NEC and TEC cultures. Finally, we found that basic FGF (bFGF) exerts potent inhibitory effects on many TGFβ-regulated genes but operates in tandem with TGFβ to up-regulate others. EC challenged with TGFβ secrete bFGF which blocks SMA expression in secondary cultures suggesting a cell-autonomous or lateral-inhibitory mechanism for impeding mesenchymal differentiation. Together, our results suggest that TGFβ-driven EndMT produces a spectrum of EC phenotypes with different functions that could underlie the plasticity and heterogeneity of the tumor vasculature. PMID:25634211

  3. Activation of endothelial β-catenin signaling induces heart failure.

    PubMed

    Nakagawa, Akito; Naito, Atsuhiko T; Sumida, Tomokazu; Nomura, Seitaro; Shibamoto, Masato; Higo, Tomoaki; Okada, Katsuki; Sakai, Taku; Hashimoto, Akihito; Kuramoto, Yuki; Oka, Toru; Lee, Jong-Kook; Harada, Mutsuo; Ueda, Kazutaka; Shiojima, Ichiro; Limbourg, Florian P; Adams, Ralf H; Noda, Tetsuo; Sakata, Yasushi; Akazawa, Hiroshi; Komuro, Issei

    2016-01-01

    Activation of β-catenin-dependent canonical Wnt signaling in endothelial cells plays a key role in angiogenesis during development and ischemic diseases, however, other roles of Wnt/β-catenin signaling in endothelial cells remain poorly understood. Here, we report that sustained activation of β-catenin signaling in endothelial cells causes cardiac dysfunction through suppressing neuregulin-ErbB pathway in the heart. Conditional gain-of-function mutation of β-catenin, which activates Wnt/β-catenin signaling in Bmx-positive arterial endothelial cells (Bmx/CA mice) led to progressive cardiac dysfunction and 100% mortality at 40 weeks after tamoxifen treatment. Electron microscopic analysis revealed dilatation of T-tubules and degeneration of mitochondria in cardiomyocytes of Bmx/CA mice, which are similar to the changes observed in mice with decreased neuregulin-ErbB signaling. Endothelial expression of Nrg1 and cardiac ErbB signaling were suppressed in Bmx/CA mice. The cardiac dysfunction of Bmx/CA mice was ameliorated by administration of recombinant neuregulin protein. These results collectively suggest that sustained activation of Wnt/β-catenin signaling in endothelial cells might be a cause of heart failure through suppressing neuregulin-ErbB signaling, and that the Wnt/β-catenin/NRG axis in cardiac endothelial cells might become a therapeutic target for heart failure. PMID:27146149

  4. Tracing behavior of endothelial cells promotes vascular network formation.

    PubMed

    Yasuda, Noriko; Sekine, Hidekazu; Bise, Ryoma; Okano, Teruo; Shimizu, Tatsuya

    2016-05-01

    The in vitro formation of network structures derived from endothelial cells in grafts before transplantation contributes to earlier engraftment. In a previous study, endothelial cells migrated to form a net-shaped structure in co-culture. However, the specific network formation behavior of endothelial cells during migration remains unclear. In this study, we demonstrated the tracing behavior and cell cycle of endothelial cells using Fucci-labeled (Fluorescent Ubiquitination-based Cell Cycle Indicator) endothelial cells. Here, we observed the co-culture of Fucci-labeled human umbilical vein endothelial cells (HUVECs) together with normal human dermal fibroblasts (NHDFs) using time-lapse imaging and analyzed by multicellular concurrent tracking. In the G0/G1 period, HUVECs migrate faster than in the S/G2/M period, because G0/G1 is the mobile phase and S/G2/M is the proliferation phase in the cell cycle. When HUVECs are co-cultured, they tend to move randomly until they find existing tracks that they then follow to form clusters. Extracellular matrix (ECM) staining showed that collagen IV, laminin and thrombospondin deposited in accordance with endothelial cell networks. Therefore the HUVECs may migrate on the secreted ECM and exhibit tracing behavior, where the HUVECs migrate toward each other. These results suggested that ECM and a cell phase contributed to form a network by accelerating cell migration.

  5. Immunohistochemical localization of endothelial cell markers in solitary fibrous tumor.

    PubMed

    Sawada, Namie; Ishiwata, Toshiyuki; Naito, Zenya; Maeda, Shotaro; Sugisaki, Yuichi; Asano, Goro

    2002-12-01

    Solitary fibrous tumor (SFT) is an uncommon tumor first reported in the pleura, but recently described in other tissues. CD34, which is expressed in hematopoietic stem cells, endothelial progenitor cells and vascular endothelial cells, is observed in most SFT and some investigators believe that its expression is a definitive marker of this tumor. In the present study, the expression of vascular endothelial cell markers, such as vascular endothelial growth factor receptor (VEGFR)-1 (flt-1), VEGFR-2 (flk-1/KDR), Tie-2 and c-Met, was examined in SFT to clarify the relationship between SFT and endothelial cells. By immunohistochemical staining of tumor cells from 26 patients, VEGFR-1 was detected in 24 (92%), VEGFR-2 in five (19%), Tie-2 in 14 (54%), and c-Met, a specific receptor of hepatocyte growth factor (HGF) in 23 patients (88%). Furthermore, VEGFR-3 (flt-4) immunoreactivity was detected in eight of 26 patients (31%). In contrast, VEGF, VEGF-C and HGF, which are ligands for the receptors, were not localized in the SFT cells. These findings indicate that most SFT may closely relate to vascular or lymphatic endothelial cells and the endothelial growth factors may contribute to the growth of SFT in a paracrine manner.

  6. Endothelial cells derived from human embryonic stem cells

    NASA Astrophysics Data System (ADS)

    Levenberg, Shulamit; Golub, Justin S.; Amit, Michal; Itskovitz-Eldor, Joseph; Langer, Robert

    2002-04-01

    Human embryonic stem cells have the potential to differentiate into various cell types and, thus, may be useful as a source of cells for transplantation or tissue engineering. We describe here the differentiation steps of human embryonic stem cells into endothelial cells forming vascular-like structures. The human embryonic-derived endothelial cells were isolated by using platelet endothelial cell-adhesion molecule-1 (PECAM1) antibodies, their behavior was characterized in vitro and in vivo, and their potential in tissue engineering was examined. We show that the isolated embryonic PECAM1+ cells, grown in culture, display characteristics similar to vessel endothelium. The cells express endothelial cell markers in a pattern similar to human umbilical vein endothelial cells, their junctions are correctly organized, and they have high metabolism of acetylated low-density lipoprotein. In addition, the cells are able to differentiate and form tube-like structures when cultured on matrigel. In vivo, when transplanted into SCID mice, the cells appeared to form microvessels containing mouse blood cells. With further studies, these cells could provide a source of human endothelial cells that could be beneficial for potential applications such as engineering new blood vessels, endothelial cell transplantation into the heart for myocardial regeneration, and induction of angiogenesis for treatment of regional ischemia.

  7. Endothelial Barrier and Its Abnormalities in Cardiovascular Disease

    PubMed Central

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

    2015-01-01

    Endothelial cells (ECs) form a unique barrier between the vascular lumen and the vascular wall. In addition, the endothelium is highly metabolically active. In cardiovascular disease such as atherosclerosis and hypertension, normal endothelial function could be severely disturbed leading to endothelial dysfunction that then could progress to complete and irreversible loss of EC functionality and contribute to entire vascular dysfunction. Proatherogenic stimuli such as diabetes, dyslipidemia, and oxidative stress could initiate endothelial dysfunction and in turn vascular dysfunction and lead to the development of atherosclerotic arterial disease, a background for multiple cardiovascular disorders including coronary artery disease, acute coronary syndrome, stroke, and thrombosis. Intercellular junctions between ECs mediate the barrier function. Proinflammatory stimuli destabilize the junctions causing the disruption of the endothelial barrier and increased junctional permeability. This facilitates transendothelial migration of immune cells to the arterial intima and induction of vascular inflammation. Proatherogenic stimuli attack endothelial microtubule function that is regulated by acetylation of tubulin, an essential microtubular constituent. Chemical modification of tubulin caused by cardiometabolic risk factors and oxidative stress leads to reorganization of endothelial microtubules. These changes destabilize vascular integrity and increase permeability, which finally results in increasing cardiovascular risk. PMID:26696899

  8. Endothelial Barrier and Its Abnormalities in Cardiovascular Disease.

    PubMed

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

    2015-01-01

    Endothelial cells (ECs) form a unique barrier between the vascular lumen and the vascular wall. In addition, the endothelium is highly metabolically active. In cardiovascular disease such as atherosclerosis and hypertension, normal endothelial function could be severely disturbed leading to endothelial dysfunction that then could progress to complete and irreversible loss of EC functionality and contribute to entire vascular dysfunction. Proatherogenic stimuli such as diabetes, dyslipidemia, and oxidative stress could initiate endothelial dysfunction and in turn vascular dysfunction and lead to the development of atherosclerotic arterial disease, a background for multiple cardiovascular disorders including coronary artery disease, acute coronary syndrome, stroke, and thrombosis. Intercellular junctions between ECs mediate the barrier function. Proinflammatory stimuli destabilize the junctions causing the disruption of the endothelial barrier and increased junctional permeability. This facilitates transendothelial migration of immune cells to the arterial intima and induction of vascular inflammation. Proatherogenic stimuli attack endothelial microtubule function that is regulated by acetylation of tubulin, an essential microtubular constituent. Chemical modification of tubulin caused by cardiometabolic risk factors and oxidative stress leads to reorganization of endothelial microtubules. These changes destabilize vascular integrity and increase permeability, which finally results in increasing cardiovascular risk.

  9. Assessment of Endothelial Dysfunction in Childhood Obesity and Clinical Use

    PubMed Central

    Hoymans, Vicky Y.; Van Craenenbroeck, Amaryllis H.; Vissers, Dirk K.; Vrints, Christiaan J.; Conraads, Viviane M.

    2013-01-01

    The association of obesity with noncommunicable diseases, such as cardiovascular complications and diabetes, is considered a major threat to the management of health care worldwide. Epidemiological findings show that childhood obesity is rapidly rising in Western society, as well as in developing countries. This pandemic is not without consequences and can affect the risk of future cardiovascular disease in these children. Childhood obesity is associated with endothelial dysfunction, the first yet still reversible step towards atherosclerosis. Advanced research techniques have added further insight on how childhood obesity and associated comorbidities lead to endothelial dysfunction. Techniques used to measure endothelial function were further brought to perfection, and novel biomarkers, including endothelial progenitor cells, were discovered. The aim of this paper is to provide a critical overview on both in vivo as well as in vitro markers for endothelial integrity. Additionally, an in-depth description of the mechanisms that disrupt the delicate balance between endothelial damage and repair will be given. Finally, the effects of lifestyle interventions and pharmacotherapy on endothelial dysfunction will be reviewed. PMID:23691262

  10. Phenotypic Expression of ADAMTS13 in Glomerular Endothelial Cells

    PubMed Central

    Tati, Ramesh; Kristoffersson, Ann-Charlotte; Ståhl, Anne-lie; Mörgelin, Matthias; Motto, David; Satchell, Simon; Mathieson, Peter; Manea-Hedström, Minola; Karpman, Diana

    2011-01-01

    Background ADAMTS13 is the physiological von Willebrand factor (VWF)-cleaving protease. The aim of this study was to examine ADAMTS13 expression in kidneys from ADAMTS13 wild-type (Adamts13+/+) and deficient (Adamts13−/−) mice and to investigate the expression pattern and bioactivity in human glomerular endothelial cells. Methodology/Principal Findings Immunohistochemistry was performed on kidney sections from ADAMTS13 wild-type and ADAMTS13-deficient mice. Phenotypic differences were examined by ultramorphology. ADAMTS13 expression in human glomerular endothelial cells and dermal microvascular endothelial cells was investigated by real-time PCR, flow cytometry, immunofluorescence and immunoblotting. VWF cleavage was demonstrated by multimer structure analysis and immunoblotting. ADAMTS13 was demonstrated in glomerular endothelial cells in Adamts13+/+ mice but no staining was visible in tissue from Adamts13−/− mice. Thickening of glomerular capillaries with platelet deposition on the vessel wall was detected in Adamts13−/− mice. ADAMTS13 mRNA and protein were detected in both human endothelial cells and the protease was secreted. ADAMTS13 activity was demonstrated in glomerular endothelial cells as cleavage of VWF. Conclusions/Significance Glomerular endothelial cells express and secrete ADAMTS13. The proteolytic activity could have a protective effect preventing deposition of platelets along capillary lumina under the conditions of high shear stress present in glomerular capillaries. PMID:21720563

  11. 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

  12. Prolonged cyclic strain inhibits human endothelial cell growth.

    PubMed

    Peyton, Kelly J; Liu, Xiao-ming; Durante, William

    2016-01-01

    The vascular endothelium is continuously exposed to cyclic mechanical strain due to the periodic change in vessel diameter as a result of pulsatile blood flow. Since emerging evidence indicates the cyclic strain plays an integral role in regulating endothelial cell function, the present study determined whether application of a physiologic regimen of cyclic strain (6% at 1 hertz) influences the proliferation of human arterial endothelial cells. Prolonged exposure of human dermal microvascular or human aortic endothelial cells to cyclic strain for up to 7 days resulted in a marked decrease in cell growth. The strain-mediated anti-proliferative effect was associated with the arrest of endothelial cells in the G2/M phase of the cell cycle, did not involve cell detachment or cytotoxicity, and was due to the induction of p21. Interestingly, the inhibition in endothelial cell growth was independent of the strain regimen since prolonged application of constant or intermittent 6% strain was also able to block endothelial cell proliferation. The ability of chronic physiologic cyclic strain to inhibit endothelial cell growth represents a previously unrecognized mechanism by which hemodynamic forces maintain these cells in a quiescent, non-proliferative state. PMID:26709656

  13. Endothelial HIF signaling regulates pulmonary fibrosis-associated pulmonary hypertension.

    PubMed

    Bryant, Andrew J; Carrick, Ryan P; McConaha, Melinda E; Jones, Brittany R; Shay, Sheila D; Moore, Christy S; Blackwell, Thomas R; Gladson, Santhi; Penner, Niki L; Burman, Ankita; Tanjore, Harikrishna; Hemnes, Anna R; Karwandyar, Ayub K; Polosukhin, Vasiliy V; Talati, Megha A; Dong, Hui-Jia; Gleaves, Linda A; Carrier, Erica J; Gaskill, Christa; Scott, Edward W; Majka, Susan M; Fessel, Joshua P; Haase, Volker H; West, James D; Blackwell, Timothy S; Lawson, William E

    2016-02-01

    Pulmonary hypertension (PH) complicating chronic parenchymal lung disease, such as idiopathic pulmonary fibrosis, results in significant morbidity and mortality. Since the hypoxia-inducible factor (HIF) signaling pathway is important for development of pulmonary hypertension in chronic hypoxia, we investigated whether HIF signaling in vascular endothelium regulates development of PH related to pulmonary fibrosis. We generated a transgenic model in which HIF is deleted within vascular endothelial cells and then exposed these mice to chronic intraperitoneal bleomycin to induce PH associated with lung fibrosis. Although no differences in the degree of fibrotic remodeling were observed, we found that endothelial HIF-deficient mice were protected against development of PH, including right ventricle and pulmonary vessel remodeling. Similarly, endothelial HIF-deficient mice were protected from PH after a 4-wk exposure to normobaric hypoxia. In vitro studies of pulmonary vascular endothelial cells isolated from the HIF-targeted mice and controls revealed that endothelial HIF signaling increases endothelial cell expression of connective tissue growth factor, enhances vascular permeability, and promotes pulmonary artery smooth muscle cell proliferation and wound healing ability, all of which have the potential to impact the development of PH in vivo. Taken together, these studies demonstrate that vascular endothelial cell HIF signaling is necessary for development of hypoxia and pulmonary fibrosis associated PH. As such, HIF and HIF-regulated targets represent a therapeutic target in these conditions.

  14. Phagocytosis by glomerular endothelial cells in infection-related glomerulopathy.

    PubMed

    van Velthuysen, M L; Mayen, A E; Prins, F A; de Heer, E; Bruijn, J A; Fleuren, G J

    1994-01-01

    Glomerulonephritis in BALB/c mice following infection with Trypanosoma brucei is characterized by albuminuria and glomerular deposition of immunoglobulins. Electron-dense deposits are present in the mesangium, as well as subendothelially and subepithelially along the glomerular capillary wall. In this study the nature of intracytoplasmic, electron-dense, round structures observed in glomerular endothelial cells was investigated by immunoelectron-microscopy and enzyme histochemistry. The presence of these structures was related in time with the development of proteinuria. Mice from the C57BL10 strain, which upon infection develop glomerular immune complexes without proteinuria, were examined as well. The results demonstrated that the first endothelial changes, occurring 3-4 weeks after infection, were swelling of endothelial cells containing intracytoplasmic, electron-dense, round structures. These changes were seen prior to the onset of proteinuria, and were not present in glomeruli of mice that did not develop proteinuria. The endothelial granules were shown to contain immunoglobulins and typical lysosomal enzymes, providing evidence for phagocytosis by the glomerular endothelial cells. Liver endothelial cells did not show comparable changes. Thus, local phagocytosis by glomerular endothelial cells is shown to be a specific event in the development of glomerular disease. PMID:7800204

  15. Effect of metformin on insulin-resistant endothelial cell function

    PubMed Central

    CHEN, HAIYAN; LI, JIE; YANG, OU; KONG, JIAN; LIN, GUANGZHU

    2015-01-01

    The aim of the present study was to investigate the effect of metformin on the function of insulin-resistant (IR) endothelial cells. A model of IR endothelial cells was established by incubating cells with 30 mM glucose, 1 μM dexamethasone and various concentrations of insulin. The nitric oxide (NO) content of the endothelial cells was determined by measuring the rate of nitroreductase production; the endothelin (ET) concentration was examined by enzyme-linked immunosorbent assay; and the expression levels of endothelial nitric oxide synthase (eNOS) were detected using western blotting. The optimal conditions for inducing insulin resistance in endothelial cells were a combination treatment of 10−4 mmol/l insulin, 30 mM glucose and 1 μM dexamethasone for 48 h. Notably, metformin administration significantly increased the NO content and reduced the ET-1 concentration in the IR cells compared with the non-treated control cells (P<0.05); furthermore, metformin significantly increased the intracellular eNOS protein expression in IR endothelial cells compared with the non-treated control cells (P<0.05), with an optimal metformin concentration of 10−3 mmol/l. Thus, the present study identified that metformin improves the function of IR endothelial cells, possibly through promoting eNOS protein expression and increasing the NO content. PMID:25663871

  16. Mechanotransduction at the basis of endothelial barrier function.

    PubMed

    Gulino-Debrac, Danielle

    2013-04-01

    Destabilization of cell-cell contacts involved in the maintenance of endothelial barrier function can lead to increased endothelial permeability. This increase in endothelial permeability results in an anarchical movement of fluid, solutes and cells outside the vasculature and into the surrounding tissues, thereby contributing to various diseases such as stroke or pulmonary edema. Thus, a better understanding of the molecular mechanisms regulating endothelial cell junction integrity is required for developing new therapies for these diseases. In this review, we describe the mechanotransduction mechanism at the basis of adherens junction strengthening at endothelial cell-cell contacts. More particularly, we report on the emerging role of α-catenin and EPLIN that act as a mechanotransmitter of myosin-IIgenerated traction forces. The interplay between α-catenin, EPLIN and the myosin-II machinery initiates the junctional recruitment of vinculin and α-actinin leading to a drastic remodeling of the actin cytoskeleton and to cortical actin ring reshaping. The pathways initiated by tyrosine phosphorylation of VE-cadherin at the basis of endothelial cell-cell junction remodeling is also reported, as it may be interrelated to α-catenin/ EPLIN-mediated mechanotransduction mechanisms. We also describe the junctional mechanosensory complex composed of PECAM-1, VE-cadherin and VEGFR2 that is able to transmit signaling pathway under the onset of shear stress. This mechanosensing mechanism, involved in the earliest events promoting atherogenesis, is required for endothelial cell alignment along flow direction. PMID:24665386

  17. Activation of endothelial β-catenin signaling induces heart failure

    PubMed Central

    Nakagawa, Akito; Naito, Atsuhiko T.; Sumida, Tomokazu; Nomura, Seitaro; Shibamoto, Masato; Higo, Tomoaki; Okada, Katsuki; Sakai, Taku; Hashimoto, Akihito; Kuramoto, Yuki; Oka, Toru; Lee, Jong-Kook; Harada, Mutsuo; Ueda, Kazutaka; Shiojima, Ichiro; Limbourg, Florian P.; Adams, Ralf H.; Noda, Tetsuo; Sakata, Yasushi; Akazawa, Hiroshi; Komuro, Issei

    2016-01-01

    Activation of β-catenin-dependent canonical Wnt signaling in endothelial cells plays a key role in angiogenesis during development and ischemic diseases, however, other roles of Wnt/β-catenin signaling in endothelial cells remain poorly understood. Here, we report that sustained activation of β-catenin signaling in endothelial cells causes cardiac dysfunction through suppressing neuregulin-ErbB pathway in the heart. Conditional gain-of-function mutation of β-catenin, which activates Wnt/β-catenin signaling in Bmx-positive arterial endothelial cells (Bmx/CA mice) led to progressive cardiac dysfunction and 100% mortality at 40 weeks after tamoxifen treatment. Electron microscopic analysis revealed dilatation of T-tubules and degeneration of mitochondria in cardiomyocytes of Bmx/CA mice, which are similar to the changes observed in mice with decreased neuregulin-ErbB signaling. Endothelial expression of Nrg1 and cardiac ErbB signaling were suppressed in Bmx/CA mice. The cardiac dysfunction of Bmx/CA mice was ameliorated by administration of recombinant neuregulin protein. These results collectively suggest that sustained activation of Wnt/β-catenin signaling in endothelial cells might be a cause of heart failure through suppressing neuregulin-ErbB signaling, and that the Wnt/β-catenin/NRG axis in cardiac endothelial cells might become a therapeutic target for heart failure. PMID:27146149

  18. Dermal stem cells can differentiate down an endothelial lineage.

    PubMed

    Bell, Emma; Richardson, Gavin D; Jahoda, Colin A; Gledhill, Karl; Phillips, Helen M; Henderson, Deborah; Owens, W Andrew; Hole, Nicholas

    2012-11-01

    In this study, we have demonstrated that cells of neural crest origin located in the dermal papilla (DP) exhibit endothelial marker expression and a functional activity. When grown in endothelial growth media, DP primary cultures upregulate expression of vascular endothelial growth factor receptor 1 (FLT1) mRNA and downregulate expression of the dermal stem cell marker α-smooth muscle actin. DP cells have demonstrated functional characteristics of endothelial cells, including the ability to form capillary-like structures on Matrigel, increase uptake of low-density lipoprotein and upregulate ICAM1 (CD54) in response to tumour necrosis factor alpha (TNF-α) stimulation. We confirmed that these observations were not due to contaminating endothelial cells, by using DP clones. We have also used the WNT1cre/ROSA26R and WNT1cre/YFP lineage-tracing mouse models to identify a population of neural crest-derived cells in DP cultures that express the endothelial marker PECAM (CD31); these cells also form capillary-like structures on Matrigel. Importantly, cells of neural crest origin that express markers of endothelial and mesenchymal lineages exist within the dermal sheath of the vibrissae follicle.

  19. [Endothelial function and the microcirculation in diabetes mellitus].

    PubMed

    Arosio, E; Minuz, P; Prior, M

    1999-01-01

    The role of endothelial dysfunction in the pathogenesis of diabetic microangiopathy is reviewed. Reversible alterations in microcirculation, consisting of increased capillary pressure, blood flow and endothelial permeability, can be detected at an early stage in diabetes mellitus. Irreversible structural modifications of the vascular wall, such as thickening of the basal membrane due to the extracellular accumulation of proteins, take place at later stages. Atherosclerosis further affects microcirculation in diabetes mellitus by decreasing autoregulatory capacity and blood flow reserve. Endothelial dysfunction has been observed to precede the onset of microvascular lesions, as demonstrated by reduction in the vasodilatory response to vasoactive agents and by alterations in the antithrombotic properties of the endothelium. Experimental data available so far suggest that endothelial dysfunction may be directly related to hyperglycemia. Abnormalities in lipoprotein metabolism, generation of glycation end products, and increased oxidative stress may also be responsible for the endothelial dysfunction in diabetes mellitus. Insulin resistance appears to be related to endothelial dysfunction in non-insulin-dependent diabetes mellitus through a reduction in the biological activity of endothelial-derived nitric oxide.

  20. Capture of endothelial cells under flow using immobilized vascular endothelial growth factor

    PubMed Central

    Smith, Randall J.; Koobatian, Maxwell T.; Shahini, Aref; Swartz, Daniel D.; Andreadis, Stelios T.

    2015-01-01

    We demonstrate the ability of immobilized vascular endothelial growth factor (VEGF) to capture endothelial cells (EC) with high specificity under fluid flow. To this end, we engineered a surface consisting of heparin bound to poly-L-lysine to permit immobilization of VEGF through the C-terminal heparin-binding domain. The immobilized growth factor retained its biological activity as shown by proliferation of EC and prolonged activation of KDR signaling. Using a microfluidic device we assessed the ability to capture EC under a range of shear stresses from low (0.5 dyne/cm2) to physiological (15 dyne/cm2). Capture was significant for all shear stresses tested. Immobilized VEGF was highly selective for EC as evidenced by significant capture of human umbilical vein and ovine pulmonary artery EC but no capture of human dermal fibroblasts, human hair follicle derived mesenchymal stem cells, or mouse fibroblasts. Further, VEGF could capture EC from mixtures with non-EC under low and high shear conditions as well as from complex fluids like whole human blood under high shear. Our findings may have far reaching implications, as they suggest that VEGF could be used to promote endothelialization of vascular grafts or neovascularization of implanted tissues by rare but continuously circulating EC. PMID:25771020

  1. 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

  2. Endothelial Microparticle-Derived Reactive Oxygen Species: Role in Endothelial Signaling and Vascular Function.

    PubMed

    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, p47(phox), p67(phox), and p22(phox) 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

  3. Endothelial nitric oxide synthase in the microcirculation.

    PubMed

    Shu, Xiaohong; Keller, T C Stevenson; Begandt, Daniela; Butcher, Joshua T; Biwer, Lauren; Keller, Alexander S; Columbus, Linda; Isakson, Brant E

    2015-12-01

    Endothelial nitric oxide synthase (eNOS, NOS3) is responsible for producing nitric oxide (NO)--a key molecule that can directly (or indirectly) act as a vasodilator and anti-inflammatory mediator. In this review, we examine the structural effects of regulation of the eNOS enzyme, including post-translational modifications and subcellular localization. After production, NO diffuses to surrounding cells with a variety of effects. We focus on the physiological role of NO and NO-derived molecules, including microvascular effects on vessel tone and immune response. Regulation of eNOS and NO action is complicated; we address endogenous and exogenous mechanisms of NO regulation with a discussion of pharmacological agents used in clinical and laboratory settings and a proposed role for eNOS in circulating red blood cells.

  4. Endothelial glycocalyx: sweet shield of blood vessels.

    PubMed

    Van Teeffelen, Jurgen W; Brands, Judith; Stroes, Erik S; Vink, Hans

    2007-04-01

    At the time that the term glycocalyx ("sweet husk") was introduced as a description of the extracellular polysaccharide coating on cells (Bennett HS: 1963. Morphological aspects of extracellular polysaccharides. J Hist Cytochem 11:14-23.), early electron microscopic observations had shown that anionic polysaccharides were also presented by the inner surface of blood vessels but the length of these structures was considered to be small and their functional significance was unknown. Research in the past decades in the glycocalyx field has evolved, and recent estimations indicate that the endothelial glycocalyx constitutes a voluminous intravascular compartment that plays an important role in vascular wall homeostasis. Pathologic loss of glycocalyx may be associated with an impaired vascular wall protection throughout the circulatory system, whereas agonist-induced modulation of glycocalyx accessibility for circulating blood may constitute a physiologically relevant mechanism to regulate functionally perfused volume and exchange area at the microvascular level. Both aspects are discussed in the current review.

  5. The actin cytoskeleton in endothelial cell phenotypes

    PubMed Central

    Prasain, Nutan; Stevens, Troy

    2009-01-01

    Endothelium forms a semi-permeable barrier that separates blood from the underlying tissue. Barrier function is largely determined by cell-cell and cell-matrix adhesions that define the limits of cell borders. Yet, such cell-cell and cell-matrix tethering is critically reliant upon the nature of adherence within the cell itself. Indeed, the actin cytoskeleton fulfills this essential function, to provide a strong, dynamic intracellular scaffold that organizes integral membrane proteins with the cell’s interior, and responds to environmental cues to orchestrate appropriate cell shape. The actin cytoskeleton is comprised of three distinct, but interrelated structures, including actin cross-linking of spectrin within the membrane skeleton, the cortical actin rim, and actomyosin-based stress fibers. This review addresses each of these actin-based structures, and discusses cellular signals that control the disposition of actin in different endothelial cell phenotypes. PMID:19028505

  6. Endothelial-Mesenchymal Transition in Regenerative Medicine

    PubMed Central

    Medici, Damian

    2016-01-01

    Endothelial-mesenchymal transition (EndMT) is a fundamental cellular mechanism that regulates embryonic development and diseases such as cancer and fibrosis. Recent developments in biomedical research have shown remarkable potential to harness the EndMT process for tissue engineering and regeneration. As an alternative to traditional or artificial stem cell therapies, EndMT may represent a safe method for engineering new tissues to treat degenerative diseases by mimicking a process that occurs in nature. This review discusses the signaling mechanisms and therapeutic inhibitors of EndMT, as well as the role of EndMT in development, disease, acquiring stem cell properties and generating connective tissues, and its potential as a novel mechanism for tissue regeneration. PMID:27143978

  7. Effects of ultrasound upon endothelial cell ultrastructure

    NASA Astrophysics Data System (ADS)

    Rodemer, Claus; Jenne, Jürgen; Fatar, Marc; Hennerici, Michael G.; Meairs, Stephen

    2012-11-01

    A number of new brain applications for therapeutic ultrasound are emerging including drug delivery through BBB opening, enhancement of angiogenesis, sonothrombolysis and neuromodulation. Safety remains important as alterations in the cytoskeleton and tight junctions of endothelial cells have been described. In this study we characterize the in vitro effects of ultrasound on cell morphology using a new human brain cell line (hCMEC/D3). Changes in ultrastructure were analyzed with antibodies against tubulin, actin and catenin. Transport was analyzed by measuring transferrin uptake. No significant changes were seen after continuous wave ultrasound treatment of hCMEC/D3 cells grown in Opticell{trade mark, serif} chambers. We could not observe disassembled actin stress fibers or variations in the microtubule network. However, severe damage occurred in cells cultured in petri dishes.

  8. Autocrine VEGF Isoforms Differentially Regulate Endothelial Cell Behavior

    PubMed Central

    Yamamoto, Hideki; Rundqvist, Helene; Branco, Cristina; Johnson, Randall S.

    2016-01-01

    Vascular endothelial growth factor A (VEGF) is involved in all the essential biology of endothelial cells, from proliferation to vessel function, by mediating intercellular interactions and monolayer integrity. It is expressed as three major alternative spliced variants. In mice, these are VEGF120, VEGF164, and VEGF188, each with different affinities for extracellular matrices and cell surfaces, depending on the inclusion of heparin-binding sites, encoded by exons 6 and 7. To determine the role of each VEGF isoform in endothelial homeostasis, we compared phenotypes of primary endothelial cells isolated from lungs of mice expressing single VEGF isoforms in normoxic and hypoxic conditions. The differential expression and distribution of VEGF isoforms affect endothelial cell functions, such as proliferation, adhesion, migration, and integrity, which are dependent on the stability of and affinity to VEGF receptor 2 (VEGFR2). We found a correlation between autocrine VEGF164 and VEGFR2 stability, which is also associated with increased expression of proteins involved in cell adhesion. Endothelial cells expressing only VEGF188, which localizes to extracellular matrices or cell surfaces, presented a mesenchymal morphology and weakened monolayer integrity. Cells expressing only VEGF120 lacked stable VEGFR2 and dysfunctional downstream processes, rendering the cells unviable. Endothelial cells expressing these different isoforms in isolation also had differing rates of apoptosis, proliferation, and signaling via nitric oxide (NO) synthesis. These data indicate that autocrine signaling of each VEGF isoform has unique functions on endothelial homeostasis and response to hypoxia, due to both distinct VEGF distribution and VEGFR2 stability, which appears to be, at least partly, affected by differential NO production. This study demonstrates that each autocrine VEGF isoform has a distinct effect on downstream functions, namely VEGFR2-regulated endothelial cell homeostasis in

  9. Differentiation state determines neural effects on microvascular endothelial cells

    SciTech Connect

    Muffley, Lara A.; Pan, Shin-Chen; Smith, Andria N.; Ga, Maricar; Hocking, Anne M.; Gibran, Nicole S.

    2012-10-01

    Growing evidence indicates that nerves and capillaries interact paracrinely in uninjured skin and cutaneous wounds. Although mature neurons are the predominant neural cell in the skin, neural progenitor cells have also been detected in uninjured adult skin. The aim of this study was to characterize differential paracrine effects of neural progenitor cells and mature sensory neurons on dermal microvascular endothelial cells. Our results suggest that neural progenitor cells and mature sensory neurons have unique secretory profiles and distinct effects on dermal microvascular endothelial cell proliferation, migration, and nitric oxide production. Neural progenitor cells and dorsal root ganglion neurons secrete different proteins related to angiogenesis. Specific to neural progenitor cells were dipeptidyl peptidase-4, IGFBP-2, pentraxin-3, serpin f1, TIMP-1, TIMP-4 and VEGF. In contrast, endostatin, FGF-1, MCP-1 and thrombospondin-2 were specific to dorsal root ganglion neurons. Microvascular endothelial cell proliferation was inhibited by dorsal root ganglion neurons but unaffected by neural progenitor cells. In contrast, microvascular endothelial cell migration in a scratch wound assay was inhibited by neural progenitor cells and unaffected by dorsal root ganglion neurons. In addition, nitric oxide production by microvascular endothelial cells was increased by dorsal root ganglion neurons but unaffected by neural progenitor cells. -- Highlights: Black-Right-Pointing-Pointer Dorsal root ganglion neurons, not neural progenitor cells, regulate microvascular endothelial cell proliferation. Black-Right-Pointing-Pointer Neural progenitor cells, not dorsal root ganglion neurons, regulate microvascular endothelial cell migration. Black-Right-Pointing-Pointer Neural progenitor cells and dorsal root ganglion neurons do not effect microvascular endothelial tube formation. Black-Right-Pointing-Pointer Dorsal root ganglion neurons, not neural progenitor cells, regulate

  10. Angiotensin-converting enzyme 2 activation improves endothelial function.

    PubMed

    Fraga-Silva, Rodrigo A; Costa-Fraga, Fabiana P; Murça, Tatiane M; Moraes, Patrícia L; Martins Lima, Augusto; Lautner, Roberto Q; Castro, Carlos H; Soares, Célia Maria A; Borges, Clayton L; Nadu, Ana Paula; Oliveira, Marilene L; Shenoy, Vinayak; Katovich, Michael J; Santos, Robson A S; Raizada, Mohan K; Ferreira, Anderson J

    2013-06-01

    Diminished release and function of endothelium-derived nitric oxide coupled with increases in reactive oxygen species production is critical in endothelial dysfunction. Recent evidences have shown that activation of the protective axis of the renin-angiotensin system composed by angiotensin-converting enzyme 2, angiotensin-(1-7), and Mas receptor promotes many beneficial vascular effects. This has led us to postulate that activation of intrinsic angiotensin-converting enzyme 2 would improve endothelial function by decreasing the reactive oxygen species production. In the present study, we tested 1-[[2-(dimetilamino)etil]amino]-4-(hidroximetil)-7-[[(4-metilfenil)sulfonil]oxi]-9H-xantona-9 (XNT), a small molecule angiotensin-converting enzyme 2 activator, on endothelial function to validate this hypothesis. In vivo treatment with XNT (1 mg/kg per day for 4 weeks) improved the endothelial function of spontaneously hypertensive rats and of streptozotocin-induced diabetic rats when evaluated through the vasorelaxant responses to acetylcholine/sodium nitroprusside. Acute in vitro incubation with XNT caused endothelial-dependent vasorelaxation in aortic rings of rats. This vasorelaxation effect was attenuated by the Mas antagonist D-pro7-Ang-(1-7), and it was reduced in Mas knockout mice. These effects were associated with reduction in reactive oxygen species production. In addition, Ang II-induced reactive oxygen species production in human aortic endothelial cells was attenuated by preincubation with XNT. These results showed that chronic XNT administration improves the endothelial function of hypertensive and diabetic rat vessels by attenuation of the oxidative stress. Moreover, XNT elicits an endothelial-dependent vasorelaxation response, which was mediated by Mas. Thus, this study indicated that angiotensin-converting enzyme 2 activation promotes beneficial effects on the endothelial function and it is a potential target for treating cardiovascular disease.

  11. Vascular Accessibility of Endothelial Targeted Ferritin Nanoparticles.

    PubMed

    Khoshnejad, Makan; Shuvaev, Vladimir V; Pulsipher, Katherine W; Dai, Chuanyun; Hood, Elizabeth D; Arguiri, Evguenia; Christofidou-Solomidou, Melpo; Dmochowski, Ivan J; Greineder, Colin F; Muzykantov, Vladimir R

    2016-03-16

    Targeting nanocarriers to the endothelium, using affinity ligands to cell adhesion molecules such as ICAM-1 and PECAM-1, holds promise to improve the pharmacotherapy of many disease conditions. This approach capitalizes on the observation that antibody-targeted carriers of 100 nm and above accumulate in the pulmonary vasculature more effectively than free antibodies. Targeting of prospective nanocarriers in the 10-50 nm range, however, has not been studied. To address this intriguing issue, we conjugated monoclonal antibodies (Ab) to ICAM-1 and PECAM-1 or their single chain antigen-binding fragments (scFv) to ferritin nanoparticles (FNPs, size 12 nm), thereby producing Ab/FNPs and scFv/FNPs. Targeted FNPs retained their typical symmetric core-shell structure with sizes of 20-25 nm and ∼4-5 Ab (or ∼7-9 scFv) per particle. Ab/FNPs and scFv/FNPs, but not control IgG/FNPs, bound specifically to cells expressing target molecules and accumulated in the lungs after intravenous injection, with pulmonary targeting an order of magnitude higher than free Ab. Most intriguing, the targeting of Ab/FNPs to ICAM-1, but not PECAM-1, surpassed that of larger Ab/carriers targeted by the same ligand. These results indicate that (i) FNPs may provide a platform for targeting endothelial adhesion molecules with carriers in the 20 nm size range, which has not been previously reported; and (ii) ICAM-1 and PECAM-1 (known to localize in different domains of endothelial plasmalemma) differ in their accessibility to circulating objects of this size, common for blood components and nanocarriers. PMID:26718023

  12. Rac regulates vascular endothelial growth factor stimulated motility.

    PubMed

    Soga, N; Connolly, J O; Chellaiah, M; Kawamura, J; Hruska, K A

    2001-01-01

    During angiogenesis endothelial cells migrate towards a chemotactic stimulus. Understanding the mechanism of endothelial cell migration is critical to the therapeutic manipulation of angiogenesis and ultimately cancer prevention. Vascular endothelial growth factor (VEGF) is a potent chemotactic stimulus of endothelial cells during angiogenesis. The endothelial cell signal transduction pathway of VEGF represents a potential target for cancer therapy, but the mechanisms of post-receptor signal transduction including the roles of rho family GTPases in regulating the cytoskeletal effects of VEGF in endothelial cells are not understood. Here we analyze the mechanisms of cell migration in the mouse brain endothelial cell line (bEND3). Stable transfectants containing a tetracycline repressible expression vector were used to induce expression of Rac mutants. Endothelial cell haptotaxis was stimulated by constitutively active V12Rac on collagen and vitronectin coated supports, and chemotaxis was further stimulated by VEGF. Osteopontin coated supports were the most stimulatory to bEND3 haptotaxis, but VEGF was not effective in further increasing migration on osteopontin coated supports. Haptotaxis on support coated with collagen, vitronectin, and to a lesser degree osteopontin was inhibited by N17 Rac. N17 Rac expression blocked stimulation of endothelial cell chemotaxis by VEGF. As part of the chemotactic stimulation, VEGF caused a loss of actin organization at areas of cell-cell contact and increased stress fiber expression in endothelial cells which were directed towards pores in the transwell membrane. N17 Rac prevented the stimulation of cell-cell contact disruption and the stress fiber stimulation by VEGF. These data demonstrate two pathways of regulating endothelial cell motility, one in which Rac is activated by matrix/integrin stimulation and is a crucial modulator of endothelial cell haptotaxis. The other pathway, in the presence of osteopontin, is Rac independent

  13. Implantation of Vascular Grafts Lined with Genetically Modified Endothelial Cells

    NASA Astrophysics Data System (ADS)

    Wilson, James M.; Birinyi, Louis K.; Salomon, Robert N.; Libby, Peter; Callow, Allan D.; Mulligan, Richard C.

    1989-06-01

    The possibility of using the vascular endothelial cell as a target for gene replacement therapy was explored. Recombinant retroviruses were used to transduce the lacZ gene into endothelial cells harvested from mongrel dogs. Prosthetic vascular grafts seeded with the genetically modified cells were implanted as carotid interposition grafts into the dogs from which the original cells were harvested. Analysis of the graft 5 weeks after implantation revealed genetically modified endothelial cells lining the luminal surface of the graft. This technology could be used in the treatment of atherosclerosis disease and the design of new drug delivery systems.

  14. Rac regulates vascular endothelial growth factor stimulated motility.

    PubMed

    Soga, N; Connolly, J O; Chellaiah, M; Kawamura, J; Hruska, K A

    2001-01-01

    During angiogenesis endothelial cells migrate towards a chemotactic stimulus. Understanding the mechanism of endothelial cell migration is critical to the therapeutic manipulation of angiogenesis and ultimately cancer prevention. Vascular endothelial growth factor (VEGF) is a potent chemotactic stimulus of endothelial cells during angiogenesis. The endothelial cell signal transduction pathway of VEGF represents a potential target for cancer therapy, but the mechanisms of post-receptor signal transduction including the roles of rho family GTPases in regulating the cytoskeletal effects of VEGF in endothelial cells are not understood. Here we analyze the mechanisms of cell migration in the mouse brain endothelial cell line (bEND3). Stable transfectants containing a tetracycline repressible expression vector were used to induce expression of Rac mutants. Endothelial cell haptotaxis was stimulated by constitutively active V12Rac on collagen and vitronectin coated supports, and chemotaxis was further stimulated by VEGF. Osteopontin coated supports were the most stimulatory to bEND3 haptotaxis, but VEGF was not effective in further increasing migration on osteopontin coated supports. Haptotaxis on support coated with collagen, vitronectin, and to a lesser degree osteopontin was inhibited by N17 Rac. N17 Rac expression blocked stimulation of endothelial cell chemotaxis by VEGF. As part of the chemotactic stimulation, VEGF caused a loss of actin organization at areas of cell-cell contact and increased stress fiber expression in endothelial cells which were directed towards pores in the transwell membrane. N17 Rac prevented the stimulation of cell-cell contact disruption and the stress fiber stimulation by VEGF. These data demonstrate two pathways of regulating endothelial cell motility, one in which Rac is activated by matrix/integrin stimulation and is a crucial modulator of endothelial cell haptotaxis. The other pathway, in the presence of osteopontin, is Rac independent

  15. Neutrophil Elastase-Generated Fragment of Vascular Endothelial Growth Factor-A Stimulates Macrophage and Endothelial Progenitor Cell Migration

    PubMed Central

    Kurtagic, Elma; Rich, Celeste B.; Buczek-Thomas, Jo Ann; Nugent, Matthew A.

    2015-01-01

    Elastase released from neutrophils as part of the innate immune system has been implicated in chronic diseases such as emphysema and cardiovascular disease. We have previously shown that neutrophil elastase targets vascular endothelial growth factor-A (VEGF) for partial degradation to generate a fragment of VEGF (VEGFf) that has distinct activities. Namely, VEGFf binds to VEGF receptor 1 but not to VEGF receptor 2 and shows altered signaling compared to intact VEGF. In the present study we investigated the chemotactic function of VEGF and VEGFf released from cells by neutrophil elastase. We found that endothelial cells migrated in response to intact VEGF but not VEGFf whereas RAW 264.7 macrophages/monocytes and embryonic endothelial progenitor cells were stimulated to migrate by either VEGF or VEGFf. To investigate the role of elastase-mediated release of VEGF from cells/extracellular matrices, a co-culture system was established. High or low VEGF producing cells were co-cultured with macrophages, endothelial or endothelial progenitor cells and treated with neutrophil elastase. Elastase treatment stimulated macrophage and endothelial progenitor cell migration with the response being greater with the high VEGF expressing cells. However, elastase treatment led to decreased endothelial cell migration due to VEGF cleavage to VEGF fragment. These findings suggest that the tissue response to NE-mediated injury might involve the generation of diffusible VEGF fragments that stimulate inflammatory cell recruitment. PMID:26672607

  16. Neisseria meningitidis infection of human endothelial cells interferes with leukocyte transmigration by preventing the formation of endothelial docking structures

    PubMed Central

    Doulet, Nicolas; Donnadieu, Emmanuel; Laran-Chich, Marie-Pierre; Niedergang, Florence; Nassif, Xavier; Couraud, Pierre Olivier; Bourdoulous, Sandrine

    2006-01-01

    Neisseria meningitidis elicits the formation of membrane protrusions on vascular endothelial cells, enabling its internalization and transcytosis. We provide evidence that this process interferes with the transendothelial migration of leukocytes. Bacteria adhering to endothelial cells actively recruit ezrin, moesin, and ezrin binding adhesion molecules. These molecules no longer accumulate at sites of leukocyte–endothelial contact, preventing the formation of the endothelial docking structures required for proper leukocyte diapedesis. Overexpression of exogenous ezrin or moesin is sufficient to rescue the formation of docking structures on and leukocyte migration through infected endothelial monolayers. Inversely, expression of the dominant-negative NH2-terminal domain of ezrin markedly inhibits the formation of docking structures and leukocyte diapedesis through noninfected monolayers. Ezrin and moesin thus appear as pivotal endothelial proteins required for leukocyte diapedesis that are titrated away by N. meningitidis. These results highlight a novel strategy developed by a bacterial pathogen to hamper the host inflammatory response by interfering with leukocyte–endothelial cell interaction. PMID:16717131

  17. Conditioned medium from human umbilical vein endothelial cells markedly improves the proliferation and differentiation of circulating endothelial progenitors.

    PubMed

    Castelli, Germana; Parolini, Isabella; Cerio, Anna Maria; D'Angiò, Agnese; Pasquini, Luca; Carollo, Maria; Sargiacomo, Massimo; Testa, Ugo; Pelosi, Elvira

    2016-10-01

    Circulating endothelial progenitor cells (EPCs) have been suggested as a precious source for generating functionally competent endothelial cells (ECs), candidate for various clinical applications. However, the paucity of these progenitor cells and the technical difficulties for their in vitro growth represent a main limitation to their use. In the present study we hypothesized that the paracrine effects of human umbilical vein endothelial cells (HUVECs) may improve endothelial cell generation from cord blood (CB) EPCs. In line with this hypothesis we showed that HUVEC conditioned medium (CM) or co-culture with HUVECs markedly improved the proliferation and differentiation and delayed the senescence of CB EPCs. The endothelial-promoting effect of CM seems to be related to smaller vesicles including exosomes (sEV/exo) contained in this medium and transferred to CB CD34(+) EPCs: in fact, purified preparations of sEV/exo isolated from CM mimicked the effect of CM to sustain endothelial formation. These observations provided the interesting indication that mature ECs exert a stimulatory effect on endothelial cell differentiation from CD34(+) cells. PMID:27667168

  18. Endothelial cell markers reflecting endothelial cell dysfunction in patients with mixed connective tissue disease

    PubMed Central

    2010-01-01

    Introduction The aim of the present study was to investigate the association between cardiovascular risk factors and endothelial dysfunction in patients with mixed connective tissue disease (MCTD) and to determine which biomarkers are associated with atherosclerotic complications, such as cardiovascular disease. Methods Fifty MCTD patients and 38 healthy age-matched and sex-matched controls were enrolled in this study. In order to describe endothelial dysfunction, we assessed flow-mediated dilation (FMD), nitrate-mediated dilation (NMD) and carotid artery intima-media thickness (IMT). We investigated FMD of the brachial artery after reactive hyperemia and NMD after sublingual nitroglycerin administration, while the IMT of the common carotid artery was determined by ultrasound. Anti-U1 ribonucleoprotein (anti-U1RNP) antibodies, anti-cardiolipin (anti-CL) antibodies, anti-endothelial cell antibody (AECA) and endothelial cell markers, such as soluble thrombomodulin (TM) and von Willebrand factor antigen (vWFAg), were assessed. Results The endothelium-dependent vasodilation (FMD) was significantly impaired in patients with MCTD, as compared with controls (%FMD: 4.7 ± 4.2% vs. 8.7 ± 5.0%; P < 0.001), while the percentage NMD did not differ (%NMD: 14.3 ± 6.6% vs. 17.1 ± 6.7%; P = 0.073). Mean carotid IMT values were higher in patients than in controls (IMT: MCTD, 0.64 ± 0.13 mm vs. controls, 0.53 ± 0.14 mm; P < 0.001). FMD negatively correlated with disease duration, the levels of apolipoprotein A1, the paraoxonase-1 activity, and systolic blood pressure in MCTD patients. The percentage FMD was significantly lower in MCTD patients with cardiovascular diseases (CVD), than in those without CVD (%FMD: 3.5 ± 2.9 vs. 5.8 ± 4.8, P < 0.0002), while percentage NMD did not differ between patients with and without CVDs. Serum levels of autoantibodies (anti-U1RNP, AECA and anti-CL) were significantly higher in MCTD patients and differed between MCTD patients with and

  19. Validation of an endothelial roll preparation for Descemet Membrane Endothelial Keratoplasty by a cornea bank using "no touch" dissection technique.

    PubMed

    Marty, Anne-Sophie; Burillon, Carole; Desanlis, Adeline; Damour, Odile; Kocaba, Viridiana; Auxenfans, Céline

    2016-06-01

    Descemet Membrane Endothelial Keratoplasty (DMEK) selectively replaces the damaged posterior part of the cornea. However, the DMEK technique relies on a manually-performed dissection that is time-consuming, requires training and presents a potential risk of endothelial graft damages leading to surgery postponement when performed by surgeons in the operative room. To validate precut corneal tissue preparation for DMEK provided by a cornea bank in order to supply a quality and security precut endothelial tissue. The protocol was a technology transfer from the Netherlands Institute for Innovative Ocular Surgery (NIIOS) to Lyon Cornea Bank, after formation in NIIOS to the DMEK "no touch" dissection technique. The technique has been validated in selected conditions (materials, microscope) and after a learning curve, cornea bank technicians prepared endothelial tissue for DMEK. Endothelial cells densities (ECD) were evaluated before and after preparation, after storage and transport to the surgery room. Microbiological and histological controls have been done. Twenty corneas were manually dissected; 18 without tears. Nineteen endothelial grafts formed a double roll. The ECD loss after cutting was 3.3 % (n = 19). After transportation 7 days later, we found an ECD loss of 25 % (n = 12). Three days after cutting and transportation, we found 2.1 % of ECD loss (n = 7). Histology found an endothelial cells monolayer lying on Descemet membrane. The mean thickness was 12 ± 2.2 µm (n = 4). No microbial contamination was found (n = 19). Endothelial roll stability has been validated at 3 days in our cornea bank. Cornea bank technicians trained can deliver to surgeons an ECD controlled, safety and ready to use endothelial tissue, for DMEK by "no touch" technique, allowing time saving, quality and security for surgeons.

  20. Electrochemical Rectification of Redox Mediators Using Porphyrin-Based Molecular Multilayered Films on ITO Electrodes.

    PubMed

    Civic, Marissa R; Dinolfo, Peter H

    2016-08-10

    Electrochemical charge transfer through multilayer thin films of zinc and nickel 5,10,15,20-tetra(4-ethynylphenyl) porphyrin constructed via copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) "click" chemistry was examined. Current rectification toward various outer-sphere redox probes is revealed with increasing numbers of layers, as these films possess insulating properties over the neutral potential range of the porphyrin, then become conductive upon reaching its oxidation potential. Interfacial electron transfer rates of mediator-dye interactions toward [Co(bpy)3](2+), [Co(dmb)3](2+), [Co(NO2-phen)3](2+), [Fe(bpy)3](2+), and ferrocene (Fc), all outer-sphere redox species, were measured by hydrodynamic methods. The ability to modify electroactive films' interfacial electron transfer rates, as well as current rectification toward redox species, has broad applicability in a number of devices, particularly photovoltaics and photogalvanics.

  1. Heme biomolecule as redox mediator and oxygen shuttle for efficient charging of lithium-oxygen batteries

    PubMed Central

    Ryu, Won-Hee; Gittleson, Forrest S.; Thomsen, Julianne M.; Li, Jinyang; Schwab, Mark J.; Brudvig, Gary W.; Taylor, André D.

    2016-01-01

    One of the greatest challenges with lithium-oxygen batteries involves identifying catalysts that facilitate the growth and evolution of cathode species on an oxygen electrode. Heterogeneous solid catalysts cannot adequately address the problematic overpotentials when the surfaces become passivated. However, there exists a class of biomolecules which have been designed by nature to guide complex solution-based oxygen chemistries. Here, we show that the heme molecule, a common porphyrin cofactor in blood, can function as a soluble redox catalyst and oxygen shuttle for efficient oxygen evolution in non-aqueous Li-O2 batteries. The heme's oxygen binding capability facilitates battery recharge by accepting and releasing dissociated oxygen species while benefiting charge transfer with the cathode. We reveal the chemical change of heme redox molecules where synergy exists with the electrolyte species. This study brings focus to the rational design of solution-based catalysts and suggests a sustainable cross-link between biomolecules and advanced energy storage. PMID:27759005

  2. Cyclometalated ruthenium(II) complexes as efficient redox mediators in peroxidase catalysis.

    PubMed

    Alpeeva, Inna S; Soukharev, Valentin S; Alexandrova, Larissa; Shilova, Nadezhda V; Bovin, Nicolai V; Csöregi, Elisabeth; Ryabov, Alexander D; Sakharov, Ivan Yu

    2003-07-01

    Cyclometalated ruthenium(II) complexes, [Ru(II)(C~N)(N~N)(2)]PF(6) [HC~N=2-phenylpyridine (Hphpy) or 2-(4'-tolyl)pyridine; N~N=2,2'-bipyridine, 1,10-phenanthroline, or 4,4'-dimethyl-2,2'-bipyridine], are rapidly oxidized by H(2)O(2) catalyzed by plant peroxidases to the corresponding Ru(III) species. The commercial isoenzyme C of horseradish peroxidase (HRP-C) and two recently purified peroxidases from sweet potato (SPP) and royal palm tree (RPTP) have been used. The most favorable conditions for the oxidation have been evaluated by varying the pH, buffer, and H(2)O(2) concentrations and the apparent second-order rate constants ( k(app)) have been measured. All the complexes studied are oxidized by HRP-C at similar rates and the rate constants k(app) are identical to those known for the best substrates of HRP-C (10(6)-10(7) M(-1) s(-1)). Both cationic (HRP-C) and anionic (SPP and RPTP) peroxidases show similar catalytic efficiency in the oxidation of the Ru(II) complexes. The mediating capacity of the complexes has been evaluated using the SPP-catalyzed co-oxidation of [Ru(II)(phpy)(bpy)(2)]PF(6) and catechol as a poor peroxidase substrate as an example. The rate of enzyme-catalyzed oxidation of catechol increases more than 10000-fold in the presence of the ruthenium complex. A simple routine for calculating the rate constant k(c) for the oxidation of catechol by the Ru(III) complex generated enzymatically from [Ru(II)(phpy)(bpy)(2)](+) is proposed. It is based on the accepted mechanism of peroxidase catalysis and involves spectrophotometric measurements of the limiting Ru(II) concentration at different concentrations of catechol. The calculated k(c) value of 0.75 M(-1) s(-1) shows that the cyclometalated Ru(II) complexes are efficient mediators in peroxidase catalysis. PMID:12774217

  3. Dietary selenium protect against redox-mediated immune suppression induced by methylmercury exposure.

    PubMed

    Li, Xuan; Yin, Daqiang; Yin, Jiaoyang; Chen, Qiqing; Wang, Rui

    2014-10-01

    The antagonism between selenium (Se) and mercury (Hg) has been widely recognized, however, the protective role of Se against methylmercury (MeHg) induced immunotoxicity and the underlying mechanism is still unclear. In the current study, MeHg exposure (0.01 mM via drinking water) significantly inhibited the lymphoproliferation and NK cells functions of the female Balb/c mice, while dietary Se supplementation (as Se-rich yeast) partly or fully recovered the observed immunotoxicity, indicating the protective role of Se against MeHg-induced immune suppression in mice. Besides, MeHg exposure promoted the generation of the reactive oxygen species (ROS), reduced the levels of nonenzymic and enzymic antioxidants in target organs, while dietary Se administration significantly diminished the MeHg-induced oxidative stress and subsequent cellular dysfunctions (lipid peroxidation and protein oxidation). Two possible mechanisms of Se's protective effects were further revealed. Firstly, the reduction of mercury concentrations (less than 25%, modulated by Se supplementation) in the target organs might contribute, but not fully explain the alleviated immune suppression. Secondly and more importantly, Se could help to maintain/or elevate the activities of several key antioxidants, therefore protect the immune cells against MeHg-induced oxidative damage.

  4. Redox-mediated modification of PLZF by SUMO-1 and ubiquitin

    SciTech Connect

    Kang, Soo Im; Choi, Hae Woong; Kim, Ick Young

    2008-05-16

    Earlier, we reported that the transcriptional repressor promyelocytic leukemia zinc-finger protein (PLZF) is sumoylated at position K242, and the sumoylation regulated its biological function. Here, we show that the sumoylation site can be modified by ubiquitin. The stability and nuclear localization of PLZF were regulated by the antagonistic relationship between sumoylation and ubiquitination. We observed the antagonistic effects of ubiquitin and SUMO-1 on PLZF under oxidative stress induced by serum deprivation. Thus, the choice between modification of PLZF by SUMO or ubiquitin was determined by the intracellular level of ROS, which was generated by serum deprivation that inactivated the SUMO-conjugating enzymes Uba2 and Ubc9, and resulted in decrease of sumoylation. The ubiquitination was increased under these conditions. The expression of BID, a known transcriptional target protein of PLZF, was decreased, and the consequent apoptosis was induced by the ROS generated during serum starvation. On the basis of these results, we propose that PLZF post-translational modification is controlled by intracellular ROS, and the biological function of PLZF is regulated by sumoylation and ubiquitination.

  5. Surfactant-Templated Synthesis of Polypyrrole Nanocages as Redox Mediators for Efficient Energy Storage

    NASA Astrophysics Data System (ADS)

    Ahn, Ki-Jin; Lee, Younghee; Choi, Hojin; Kim, Min-Sik; Im, Kyungun; Noh, Seonmyeong; Yoon, Hyeonseok

    2015-09-01

    Preparation of conducting-polymer hollow nanoparticles with different diameters was accomplished by surfactant templating. An anionic surfactant, namely sodium dodecylbenzenesulfonate, formed vesicles to template with the pyrrole monomer. Subsequent chemical oxidative polymerization of the monomer yielded spherical polypyrrole (PPy) nanoparticles with hollow interiors. The diameter of the hollow nanoparticles was easily controlled by adjusting the concentration of the surfactant. Subsequently, the size-dependent electrochemical properties of the nanoparticles, including redox properties and charge/discharge behavior, were examined. By virtue of the structural advantages, the specific capacitance (max. 326 F g-1) of PPy hollow nanoparticles was approximately twice as large as that of solid PPy nanospheres. The hollow PPy nanostructure can easily be used as a conductive substrate for the preparation of metal/polymer nanohybrids through chemical and electrochemical deposition. Two different pseudocapacitive metal-oxide clusters were readily deposited on the inner and outer surfaces of the hollow nanoparticles, which resulted in an increase in the specific capacitance to 390 F g-1. In addition, the hollow nanoparticles acted as a nanocage to prevent metal ion leaching during charge/discharge, thus allowing an excellent capacitance retention of ca. 86%, even following 10,000 cycles.

  6. Surfactant-Templated Synthesis of Polypyrrole Nanocages as Redox Mediators for Efficient Energy Storage

    PubMed Central

    Ahn, Ki-Jin; Lee, Younghee; Choi, Hojin; Kim, Min-Sik; Im, Kyungun; Noh, Seonmyeong; Yoon, Hyeonseok

    2015-01-01

    Preparation of conducting-polymer hollow nanoparticles with different diameters was accomplished by surfactant templating. An anionic surfactant, namely sodium dodecylbenzenesulfonate, formed vesicles to template with the pyrrole monomer. Subsequent chemical oxidative polymerization of the monomer yielded spherical polypyrrole (PPy) nanoparticles with hollow interiors. The diameter of the hollow nanoparticles was easily controlled by adjusting the concentration of the surfactant. Subsequently, the size-dependent electrochemical properties of the nanoparticles, including redox properties and charge/discharge behavior, were examined. By virtue of the structural advantages, the specific capacitance (max. 326 F g−1) of PPy hollow nanoparticles was approximately twice as large as that of solid PPy nanospheres. The hollow PPy nanostructure can easily be used as a conductive substrate for the preparation of metal/polymer nanohybrids through chemical and electrochemical deposition. Two different pseudocapacitive metal-oxide clusters were readily deposited on the inner and outer surfaces of the hollow nanoparticles, which resulted in an increase in the specific capacitance to 390 F g−1. In addition, the hollow nanoparticles acted as a nanocage to prevent metal ion leaching during charge/discharge, thus allowing an excellent capacitance retention of ca. 86%, even following 10,000 cycles. PMID:26373685

  7. Redox-mediated reversible modulation of the photoluminescence of single quantum dots

    NASA Astrophysics Data System (ADS)

    Li, Ying; Liu, Ren-Wei; Ma, Li; Fan, Su-Na; Li, Hui; Hu, Shu-Xin; Li, Ming

    2015-07-01

    Precise control over the photoluminescence (PL) of single quantum dots (QDs) is important for their practical applications. We show that the PL of individual CdSe/ZnS core/shell QDs can be effectively enhanced and continuously modulated by electrochemically manipulating the electron transfer (ET) between the QDs and the attached redox-active ligands such as 2-mercaptoethanol (BME). We found that i) the ET from BME to the QDs’ surface trap states suppresses the blinking of the QDs, ii) the ET from the QDs’ conduction band to the oxidization product results in dimmed PL when BME is oxidized, and iii) further oxidization of BME results in a significant PL brightening. The single particle measurements help us unveil the important features hidden in ensemble measurements and understand the underlying mechanism of the PL modulation. The results also suggest a simple yet efficient method to produce bright and non-blinking QDs and offer opportunities for further development of high resolution fluorescent bioimaging and nanodevices. Project supported by the National Natural Science Foundation of China (Grant Nos. 10904164, 61275192, and 11104328).

  8. Redox-Mediated and Ionizing-Radiation-Induced Inflammatory Mediators in Prostate Cancer Development and Treatment

    PubMed Central

    Miao, Lu; Holley, Aaron K.; Zhao, Yanming; St. Clair, William H.

    2014-01-01

    Abstract Significance: Radiation therapy is widely used for treatment of prostate cancer. Radiation can directly damage biologically important molecules; however, most effects of radiation-mediated cell killing are derived from the generated free radicals that alter cellular redox status. Multiple proinflammatory mediators can also influence redox status in irradiated cells and the surrounding microenvironment, thereby affecting prostate cancer progression and radiotherapy efficiency. Recent Advances: Ionizing radiation (IR)–generated oxidative stress can regulate and be regulated by the production of proinflammatory mediators. Depending on the type and stage of the prostate cancer cells, these proinflammatory mediators may lead to different biological consequences ranging from cell death to development of radioresistance. Critical Issues: Tumors are heterogeneous and dynamic communication occurs between stromal and prostate cancer cells, and complicated redox-regulated mechanisms exist in the tumor microenvironment. Thus, antioxidant and anti-inflammatory strategies should be carefully evaluated for each patient at different stages of the disease to maximize therapeutic benefits while minimizing unintended side effects. Future Directions: Compared with normal cells, tumor cells are usually under higher oxidative stress and secrete more proinflammatory mediators. Thus, redox status is often less adaptive in tumor cells than in their normal counterparts. This difference can be exploited in a search for new cancer therapeutics and treatment regimes that selectively activate cell death pathways in tumor cells with minimal unintended consequences in terms of chemo- and radio-resistance in tumor cells and toxicity in normal tissues. Antioxid. Redox Signal. 20, 1481–1500. PMID:24093432

  9. Electrochemical Rectification of Redox Mediators Using Porphyrin-Based Molecular Multilayered Films on ITO Electrodes.

    PubMed

    Civic, Marissa R; Dinolfo, Peter H

    2016-08-10

    Electrochemical charge transfer through multilayer thin films of zinc and nickel 5,10,15,20-tetra(4-ethynylphenyl) porphyrin constructed via copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) "click" chemistry was examined. Current rectification toward various outer-sphere redox probes is revealed with increasing numbers of layers, as these films possess insulating properties over the neutral potential range of the porphyrin, then become conductive upon reaching its oxidation potential. Interfacial electron transfer rates of mediator-dye interactions toward [Co(bpy)3](2+), [Co(dmb)3](2+), [Co(NO2-phen)3](2+), [Fe(bpy)3](2+), and ferrocene (Fc), all outer-sphere redox species, were measured by hydrodynamic methods. The ability to modify electroactive films' interfacial electron transfer rates, as well as current rectification toward redox species, has broad applicability in a number of devices, particularly photovoltaics and photogalvanics. PMID:27410765

  10. Redox mediators modify end product distribution in biomass fermentations by mixed ruminal microbes in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fermentation system of mixed ruminal bacteria is capable of generating large amounts of short-chain volatile fatty acids (VFA) via the carboxylate platform in vitro. These VFAs are subject to elongation to larger, more energy-dense products through reverse beta-oxidation. This study examined the...

  11. The role of H2S bioavailability in endothelial dysfunction.

    PubMed

    Wang, Rui; Szabo, Csaba; Ichinose, Fumito; Ahmed, Asif; Whiteman, Matthew; Papapetropoulos, Andreas

    2015-09-01

    Endothelial dysfunction (EDF) reflects pathophysiological changes in the phenotype and functions of endothelial cells that result from and/or contribute to a plethora of cardiovascular diseases. We review the role of hydrogen sulfide (H2S) in the pathogenesis of EDF, one of the fastest advancing research topics. Conventionally treated as an environment pollutant, H2S is also produced in endothelial cells and participates in the fine regulation of endothelial integrity and functions. Disturbed H2S bioavailability has been suggested to be a novel indicator of EDF progress and prognosis. EDF manifests in different forms in multiple pathologies, but therapeutics aimed at remedying altered H2S bioavailability may benefit all. PMID:26071118

  12. 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...

  13. Diesel exhaust particles and endothelial cells dysfunction: An update.

    PubMed

    Lawal, A O; Davids, L M; Marnewick, J L

    2016-04-01

    Epidemiological studies have shown a consistent positive correlation between exposure to particulate matter (PM) and increased mortality largely due to increased rates of cardiovascular morbidity and mortality. Diesel exhaust particles (DEPs) are major constituents of atmospheric PM and have been shown to cause disruption of the endothelial cell monolayer integrity, thereby affecting organ functions. Endothelial cells are very active metabolic components of biological tissue that performs a number of important physiological functions. Therefore, anything that compromises the integrity and functions of the endothelium will lead to organ dysfunction and disease. This review focuses on scientific evidence that link DEP exposure to endothelial cell dysfunction in various pathophysiological conditions affecting the cardiovascular system. The various mechanisms involved in the DEP-induced endothelial cell dysfunction are also addressed together with the preventive and therapeutic approaches to overcoming these challenges.

  14. Endothelial Interfaces - Master Gatekeepers of the Cardiovascular System

    NASA Astrophysics Data System (ADS)

    Junghans, Sylvia Ann; Pocivavsek, Luka; Zebda, Noureddine; Birukov, Konstantin; Waltman, Mary Jo; Majewski, Jaroslaw

    2014-03-01

    Endothelial cells, master gatekeepers of the cardiovascular system, line its inner boundary from the heart to distant capillaries constantly exposed to blood flow. Inter-endothelial signaling and the monolayer's adhesion to the underlying collagen rich basal lamina are key in physiology and disease. Using neutron scattering, we report the first-ever interfacial structure of endothelial monolayers under dynamic flow conditions mimicking the cardiovascular system. Endothelial adhesion strength (defined as the separation distance l between the basal cell membrane and solid boundary) is explained using developed interfacial potentials and intra-membrane segregation of specific adhesion proteins. Our method provides a powerful tool for the biophysical study of cellular layer adhesion strength in living tissues.

  15. A microscopic view on the renal endothelial glycocalyx.

    PubMed

    Dane, Martijn J C; van den Berg, Bernard M; Lee, Dae Hyun; Boels, Margien G S; Tiemeier, Gesa L; Avramut, M Cristina; van Zonneveld, Anton Jan; van der Vlag, Johan; Vink, Hans; Rabelink, Ton J

    2015-05-01

    Endothelial cells perform key homeostatic functions such as regulating blood flow, permeability, and aiding immune surveillance for pathogens. While endothelial activation serves normal physiological adaptation, maladaptation of these endothelial functions has been identified as an important effector mechanism in the progression of renal disease as well as the associated development of cardiovascular disease. The primary interface between blood and the endothelium is the glycocalyx. This carbohydrate-rich gel-like structure with its associated proteins mediates most of the regulatory functions of the endothelium. Because the endothelial glycocalyx is a highly dynamic and fragile structure ex vivo, and traditional tissue processing for staining and perfusion-fixation usually results in a partial or complete loss of the glycocalyx, studying its dimensions and function has proven to be challenging. In this review, we will outline the core functions of the glycocalyx and focus on different techniques to study structure-function relationships in kidney and vasculature.

  16. The role of inflammatory cytokines in endothelial dysfunction

    PubMed Central

    Zhang, C.

    2009-01-01

    Clinical and experimental data support a link between endothelial dysfunction and inflammation. Inflammatory cytokines are important protagonists in formation of atherosclerotic plaque, eliciting effects throughout the atherosclerotic vessel. Importantly, the development of atherosclerotic lesions, regardless of the risk factor, e.g., diabetes, hypertension, obesity, is characterized by disruption in normal function of the endothelial cells. Endothelial cells, which line the internal lumen of the vasculature, are part of a complex system that regulates vasodilation and vasoconstriction, growth of vascular smooth muscle cells, inflammation, and hemostasis, maintaining a proper blood supply to tissues and regulating inflammation and coagulation. Current concepts suggest that the earliest event in atherogenesis is endothelial dysfunction, manifested by deficiencies in the production of nitric oxide (NO) and prostacyclin. The focus of this review is to summarize recent evidence showing the effects of inflammation on vascular dysfunction in ischemic-heart disease, which may prompt new directions for targeting inflammation in future therapies. PMID:18600364

  17. Impact of simulated microgravity on microvascular endothelial cell apoptosis.

    PubMed

    Kang, Chun-Yan; Zou, Lin; Yuan, Ming; Wang, Yang; Li, Tian-Zhi; Zhang, Ye; Wang, Jun-Feng; Li, Yan; Deng, Xiao-Wei; Liu, Chang-Ting

    2011-09-01

    Cardiovascular deconditioning is known to occur in astronauts exposed to microgravity. Endothelial dysfunction at microcirculatory sites might contribute to cardiovascular deconditioning induced by weightlessness. Recent studies have reported changes in the morphology and gene expression of endothelial cells exposed to conditions of simulated microgravity. The present study was aimed at examining the effects of microgravity on the apoptosis of microvascular endothelial cells and the mechanism underlying these effects. We simulated a microgravity environment and found that microgravity induced microvascular endothelial cell apoptosis and that this effect was correlated with the downregulation of the PI3K/Akt pathway, increased expression of NF-κB, and depolymerization of F-actin. These findings may provide important insights into the origin of the adverse physiological changes occurring due to exposure to microgravity conditions. PMID:21287193

  18. Impact of simulated microgravity on microvascular endothelial cell apoptosis.

    PubMed

    Kang, Chun-Yan; Zou, Lin; Yuan, Ming; Wang, Yang; Li, Tian-Zhi; Zhang, Ye; Wang, Jun-Feng; Li, Yan; Deng, Xiao-Wei; Liu, Chang-Ting

    2011-09-01

    Cardiovascular deconditioning is known to occur in astronauts exposed to microgravity. Endothelial dysfunction at microcirculatory sites might contribute to cardiovascular deconditioning induced by weightlessness. Recent studies have reported changes in the morphology and gene expression of endothelial cells exposed to conditions of simulated microgravity. The present study was aimed at examining the effects of microgravity on the apoptosis of microvascular endothelial cells and the mechanism underlying these effects. We simulated a microgravity environment and found that microgravity induced microvascular endothelial cell apoptosis and that this effect was correlated with the downregulation of the PI3K/Akt pathway, increased expression of NF-κB, and depolymerization of F-actin. These findings may provide important insights into the origin of the adverse physiological changes occurring due to exposure to microgravity conditions.

  19. Mesenchymal Stem Cells Ameliorate Atherosclerotic Lesions via Restoring Endothelial Function

    PubMed Central

    Lin, Yu-Ling; Yet, Shaw-Fang; Hsu, Yuan-Tong

    2015-01-01

    Transplantation of mesenchymal stem cells (MSCs) is beneficial in myocardial infarction and hind limb ischemia, but its ability to ameliorate atherosclerosis remains unknown. Here, the effects of MSCs on inhibiting endothelial dysfunction and atherosclerosis were investigated in human/mouse endothelial cells treated with oxidized low-density lipoprotein (oxLDL) and in apolipoprotein E-deficient (apoE−/−) mice fed a high-fat diet. Treatment with oxLDL inactivated the Akt/endothelial nitric-oxide synthase (eNOS) pathway, induced eNOS degradation, and inhibited nitric oxide (NO) production in endothelial cells. Coculture with human MSCs reversed the effects of oxLDL on endothelial cells and restored Akt/eNOS activity, eNOS level, and NO production. Reduction of endothelium-dependent relaxation and subsequent plaque formation were developed in apoE−/− mice fed a high-fat diet. Systemic infusion with mouse MSCs ameliorated endothelial dysfunction and plaque formation in high-fat diet-fed apoE−/− mice. Interestingly, treatment with interleukin-8 (IL8)/macrophage inflammatory protein-2 (MIP-2) alone induced the similar effects of human/mouse MSCs on oxLDL-treated human/mouse endothelial cells. Neutralization antibodies (Abs) against IL8/MIP-2 also blocked the effects of human/mouse MSCs on oxLDL-treated human/mouse endothelial cells. Consistently, MIP-2 injection alone induced the similar effect of MSCs on the endothelial function in high-fat diet-fed apoE−/− mice. The improvement in endothelial dysfunction by mouse MSCs was also blocked when pretreating MSCs with anti-MIP-2 Abs. In conclusion, MSC transplantation improved endothelial function and plaque formation in high-fat diet-fed apoE−/− mice. Activation of the Akt/eNOS pathway in endothelium by IL8/MIP-2 is involved in the protective effect of MSCs. The study helps support the use and clarify the mechanism of MSCs for ameliorating atherosclerosis. PMID:25504897

  20. Transcriptional Regulation of Endothelial Arginase 2 by HDAC2

    PubMed Central

    Pandey, Deepesh; Sikka, Gautam; Bergman, Yehudit; Kim, Jae Hyung; Ryoo, Sungwoo

    2015-01-01

    Objective Arginase 2 is a critical target in atherosclerosis as it controls endothelial NO, proliferation, fibrosis, and inflammation. Regulators of Arg2 transcription in the endothelium have not been characterized. The goal of the current study is to determine the role of specific HDACs in the regulation of endothelial Arg2 transcription and endothelial function. Approach and Results The HDAC inhibitor, trichostatin A (TSA) increased levels of Arg2 mRNA, protein, and activity in both HAEC and mouse aortic rings. These changes occurred with both time- and dose-dependent patterns, and resulted in Arg2-dependent endothelial dysfunction. TSA and the atherogenic stimulus OxLDL enhanced the activity of common promoter regions of Arg2. HDAC inhibition with TSA also decreased endothelial NO and these effects were blunted by arginase inhibition. Non-selective class I HDAC inhibitors enhanced Arg2 expression, while the only selective inhibitor that increased Arg2 expression was mocetinostat (MGCD) – a selective inhibitor of HDACs 1 and 2. Additionally, mouse aortic rings pre-incubated with MGCD exhibited dysfunctional relaxation. Overexpression of HDAC2 (but not HDAC 1, 3 or 8) cDNA in HAEC suppressed Arg2 expression in a concentration-dependent manner, and siRNA knockdown of HDAC2 enhanced Arg2 expression. Chromatin immunoprecipitation indicated direct binding of HDAC2 to the Arg2 promoter, and HDAC2 overexpression in HAEC blocked OxLDL-mediated activation of the Arg2 promoter. Finally, overexpression of HDAC2 blocked OxLDL-mediated vascular dysfunction. Conclusions HDAC2 is a critical regulator of Arg2 expression and thereby endothelial NO and endothelial function. Overexpression or activation of HDAC2 represents a novel therapy for endothelial dysfunction and atherosclerosis. PMID:24833798

  1. Toxicity of oxygen radicals in cultured pulmonary endothelial cells

    SciTech Connect

    Autor, A.P.; Bonham, A.C.; Thies, R.L.

    1984-01-01

    Superoxide dismutase and catalase, which catalytically remove superoxide radicals and hydrogen perioxide, respectively, each separately protected cultured pulmonary artery endothelial cells from loss of membrane integrity after exposure to oxygen radicals generated either cellularly (polymorphonuclear leukocytes) or chemically (dihydroxyfumarate). Nicotinamide, a precursor of nicotinamide-adenine dinucleotide (NAD) and an inhibitor of ADP-ribose synthetase, also protected cultured endothelial cells from loss of membrane integrity in a concentration-dependent manner after exposure to dihydroxyfumarate.

  2. Variations in mass transfer to single endothelial cells.

    PubMed

    Van Doormaal, Mark A; Zhang, Ji; Wada, Shigeo; Shaw, James E; Won, Doyon; Cybulsky, Myron I; Yip, Chris M; Ethier, C Ross

    2009-06-01

    Mass transfer between flowing blood and arterial mural cells (including vascular endothelial cells) may play an important role in atherogenesis. Endothelial cells are known to have an apical surface topography that is not flat, and hence mass transfer patterns to individual endothelial cells are likely affected by the local cellular topography. The purpose of this paper is to investigate the relationship between vascular endothelial cell surface topography and cellular level mass transfer. Confluent porcine endothelial monolayers were cultured under both shear and static conditions and atomic force microscopy was used to measure endothelial cell topography. Using finite element methods and the measured cell topography, flow and concentration fields were calculated for a typical, small, blood-borne solute. A relative Sherwood number was defined as the difference between the computed Sherwood number and that predicted by the Leveque solution for mass transfer over a flat surface: this eliminates the effects of axial location on mass transfer efficiency. The average intracellular relative Sherwood number range was found to be dependent on cell height and not dependent on cell elongation due to shear stress in culture. The mass flux to individual cells reached a maximum at the highest point on the endothelial cell surface, typically corresponding to the nucleus of the cell. Therefore, for small receptor-mediated solutes, increased solute uptake efficiency can be achieved by concentrating receptors near the nucleus. The main conclusion of the work is that although the rate of mass transfer varies greatly over an individual cell, the average mass transfer rate to a cell is close to that predicted for a flat cell. In comparison to other hemodynamic factors, the topography of endothelial cells therefore seems to have little effect on mass transfer rates and is likely physiologically insignificant.

  3. Skin microvascular endothelial function as a biomarker in cardiovascular diseases?

    PubMed

    Hellmann, Marcin; Roustit, Matthieu; Cracowski, Jean-Luc

    2015-08-01

    Skin microvascular endothelial function is impaired in many cardiovascular diseases, and could be therefore considered as a representative vascular bed. However, today, available evidence allows considering skin microvascular endothelial function neither as a diagnostic biomarker nor as a prognostic biomarker in cardiovascular diseases. Large follow-up studies using standardized methods should now be conducted to assess the potential predictive value of skin microvascular function in cardiovascular diseases.

  4. Modest Visceral Fat Gain Causes Endothelial Dysfunction In Healthy Humans

    PubMed Central

    Romero-Corral, Abel; Sert-Kuniyoshi, Fatima H.; Sierra-Johnson, Justo; Orban, Marek; Gami, Apoor; Davison, Diane; Singh, Prachi; Pusalavidyasagar, Snigdha; Huyber, Christine; Votruba, Susanne; Lopez-Jimenez, Francisco; Jensen, Michael D.; Somers, Virend K.

    2014-01-01

    Objective This study sought to determine the impact of fat gain and its distribution on endothelial function in lean healthy humans. Background Endothelial dysfunction has been identified as an independent predictor of cardiovascular events. Whether fat gain impairs endothelial function is unknown. Methods A randomized controlled study to assess the effects of fat gain on endothelial function. We recruited 43 normal weight healthy volunteers (mean age 29 years; 18 women). Subjects were assigned to gain weight (approximately 4 kg) (n=35) or to maintain weight (n=8). Endothelial function (brachial artery flow mediated dilation -FMD) was measured at baseline, after fat gain (8 weeks) and after weight loss (16 weeks) for fat-gainers and at baseline and follow-up (8 weeks) for weight-maintainers. Body composition was measured by DXA and abdominal CT scans. Results After an average weight gain of 4.1 kg, fat-gainers significantly increased their total, visceral and subcutaneous fat. Blood pressure and overnight polysomnography did not change after fat gain or loss. FMD remained unchanged in weight-maintainers. FMD decreased in fat-gainers (9.1 ± 3% vs. 7.8 ± 3.2%, p =0.003), but recovered to baseline when subjects shed the gained weight. There was a significant correlation between the decrease in FMD and the increase in visceral fat gain (rho = −0.42, p=0.004), but not with subcutaneous fat gain (rho = −0.22, p=0.15). Conclusions In normal weight healthy young subjects, modest fat gain results in impaired endothelial function, even in the absence of changes in blood pressure. Endothelial function recovers after weight loss. Increased visceral rather than subcutaneous fat predicts endothelial dysfunction. PMID:20705223

  5. Involvement of local lamellipodia in endothelial barrier function.

    PubMed

    Breslin, Jerome W; Zhang, Xun E; Worthylake, Rebecca A; Souza-Smith, Flavia M

    2015-01-01

    Recently we observed that endothelial cells cultured in tightly confluent monolayers display frequent local lamellipodia, and that thrombin, an agent that increases endothelial permeability, reduces lamellipodia protrusions. This led us to test the hypothesis that local lamellipodia contribute to endothelial barrier function. Movements of subcellular structures containing GFP-actin or VE-cadherin-GFP expressed in endothelial cells were recorded using time-lapse microscopy. Transendothelial electrical resistance (TER) served as an index of endothelial barrier function. Changes in both lamellipodia dynamics and TER were assessed during baseline and after cells were treated with either the barrier-disrupting agent thrombin, or the barrier-stabilizing agent sphingosine-1-phosphate (S1P). The myosin II inhibitor blebbistatin was used to selectively block lamellipodia formation, and was used to test their role in the barrier function of endothelial cell monolayers and isolated, perfused rat mesenteric venules. Myosin light chain (MLC) phosphorylation was assessed by immunofluorescence microscopy. Rac1 and RhoA activation were evaluated using G-LISA assays. The role of Rac1 was tested with the specific inhibitor NSC23766 or by expressing wild-type or dominant negative GFP-Rac1. The results show that thrombin rapidly decreased both TER and the lamellipodia protrusion frequency. S1P rapidly increased TER in association with increased protrusion frequency. Blebbistatin nearly abolished local lamellipodia protrusions while cortical actin fibers and stress fibers remained intact. Blebbistatin also significantly decreased TER of cultured endothelial cells and increased permeability of isolated rat mesenteric venules. Both thrombin and S1P increased MLC phosphorylation and activation of RhoA. However, thrombin and S1P had differential impacts on Rac1, correlating with the changes in TER and lamellipodia protrusion frequency. Overexpression of Rac1 elevated, while NSC23766 and

  6. Endothelial dysfunction correlates with decompression bubbles in rats.

    PubMed

    Zhang, Kun; Wang, Dong; Jiang, Zhongxin; Ning, Xiaowei; Buzzacott, Peter; Xu, Weigang

    2016-09-12

    Previous studies have documented that decompression led to endothelial dysfunction with controversial results. This study aimed to clarify the relationship between endothelial dysfunction, bubble formation and decompression rate. Rats were subjected to simulated air dives with one of four decompression rates: one slow and three rapid. Bubble formation was detected ultrasonically following decompression for two hours, before measurement of endothelial related indices. Bubbles were found in only rapid-decompressed rats and the amount correlated with decompression rate with significant variability. Serum levels of ET-1, 6-keto-PGF1α, ICAM-1, VCAM-1 and MDA, lung Wet/Dry weight ratio and histological score increased, serum NO decreased following rapid decompression. Endothelial-dependent vasodilatation to Ach was reduced in pulmonary artery rings among rapid-decompressed rats. Near all the above changes correlated significantly with bubble amounts. The results suggest that bubbles may be the causative agent of decompression-induced endothelial damage and bubble amount is of clinical significance in assessing decompression stress. Furthermore, serum levels of ET-1 and MDA may serve as sensitive biomarkers with the capacity to indicate endothelial dysfunction and decompression stress following dives.

  7. Recent insights into endothelial control of leukocyte extravasation.

    PubMed

    Hordijk, Peter L

    2016-04-01

    In the process of leukocyte migration from the circulation across the vascular wall, the crosstalk with endothelial cells that line the blood vessels is essential. It is now firmly established that in endothelial cells important signaling events are initiated upon leukocyte adhesion that impinge on the regulation of cell-cell contact and control the efficiency of transendothelial migration. In addition, several external factors such as shear force and vascular stiffness were recently identified as important regulators of endothelial signaling and, consequently, leukocyte transmigration. Here, I review recent insights into endothelial signaling events that are linked to leukocyte migration across the vessel wall. In this field, protein phosphorylation and Rho-mediated cytoskeletal dynamics are still widely studied using increasingly sophisticated mouse models. In addition, activation of tyrosine phosphatases, changes in endothelial cell stiffness as well as different vascular beds have all been established as important factors in endothelial signaling and leukocyte transmigration. Finally, I address less-well-studied but interesting components in the endothelium that also control transendothelial migration, such as the ephrins and their Eph receptors, that provide novel insights in the complexity associated with this process.

  8. Fibronectin coating of oxygenator membranes enhances endothelial cell attachment

    PubMed Central

    2013-01-01

    Background Extracorporeal membrane oxygenation (ECMO) can replace the lungs’ gas exchange capacity in refractory lung failure. However, its limited hemocompatibility, the activation of the coagulation and complement system as well as plasma leakage and protein deposition hamper mid- to long-term use and have constrained the development of an implantable lung assist device. In a tissue engineering approach, lining the blood contact surfaces of the ECMO device with endothelial cells might overcome these limitations. As a first step towards this aim, we hypothesized that coating the oxygenator’s gas exchange membrane with proteins might positively influence the attachment and proliferation of arterial endothelial cells. Methods Sheets of polypropylene (PP), polyoxymethylpentene (TPX) and polydimethylsiloxane (PDMS), typical material used for oxygenator gas exchange membranes, were coated with collagen, fibrinogen, gelatin or fibronectin. Tissue culture treated well plates served as controls. Endothelial cell attachment and proliferation were analyzed for a period of 4 days by microscopic examination and computer assisted cell counting. Results Endothelial cell seeding efficiency is within range of tissue culture treated controls for fibronectin treated surfaces only. Uncoated membranes as well as all other coatings lead to lower cell attachment. A confluent endothelial cell layer develops on fibronectin coated PDMS and the control surface only. Conclusions Fibronectin increases endothelial cells’ seeding efficiency on different oxygenator membrane material. PDMS coated with fibronectin shows sustained cell attachment for a period of four days in static culture conditions. PMID:23356939

  9. Mechanisms of Endothelial Dysfunction in Hypertensive Pregnancy and Preeclampsia.

    PubMed

    Possomato-Vieira, J S; Khalil, R A

    2016-01-01

    Preeclampsia is a pregnancy-related disorder characterized by hypertension and could lead to maternal and fetal morbidity and mortality. Although the causative factors and pathophysiological mechanisms are unclear, endothelial dysfunction is a major hallmark of preeclampsia. Clinical tests and experimental research have suggested that generalized endotheliosis in the systemic, renal, cerebral, and hepatic circulation could decrease endothelium-derived vasodilators such as nitric oxide, prostacyclin, and hyperpolarization factor and increase vasoconstrictors such as endothelin-1 and thromboxane A2, leading to increased vasoconstriction, hypertension, and other manifestation of preeclampsia. In search for the upstream mechanisms that could cause endothelial dysfunction, certain genetic, demographic, and environmental risk factors have been suggested to cause abnormal expression of uteroplacental integrins, cytokines, and matrix metalloproteinases, leading to decreased maternal tolerance, apoptosis of invasive trophoblast cells, inadequate spiral arteries remodeling, reduced uterine perfusion pressure (RUPP), and placental ischemia/hypoxia. RUPP may cause imbalance between the antiangiogenic factors soluble fms-like tyrosine kinase-1 and soluble endoglin and the proangiogenic factors vascular endothelial growth factor and placental growth factor, or stimulate the release of other circulating bioactive factors such as inflammatory cytokines, hypoxia-inducible factor-1, reactive oxygen species, and angiotensin AT1 receptor agonistic autoantibodies. These circulating factors could then target endothelial cells and cause generalized endothelial dysfunction. Therapeutic options are currently limited, but understanding the factors involved in endothelial dysfunction could help design new approaches for prediction and management of preeclampsia. PMID:27451103

  10. MicroRNAs in Hyperglycemia Induced Endothelial Cell Dysfunction

    PubMed Central

    Silambarasan, Maskomani; Tan, Jun Rong; Karolina, Dwi Setyowati; Armugam, Arunmozhiarasi; Kaur, Charanjit; Jeyaseelan, Kandiah

    2016-01-01

    Hyperglycemia is closely associated with prediabetes and Type 2 Diabetes Mellitus. Hyperglycemia increases the risk of vascular complications such as diabetic retinopathy, diabetic nephropathy, peripheral vascular disease and cerebro/cardiovascular diseases. Under hyperglycemic conditions, the endothelial cells become dysfunctional. In this study, we investigated the miRNA expression changes in human umbilical vein endothelial cells exposed to different glucose concentrations (5, 10, 25 and 40 mM glucose) and at various time intervals (6, 12, 24 and 48 h). miRNA microarray analyses showed that there is a correlation between hyperglycemia induced endothelial dysfunction and miRNA expression. In silico pathways analyses on the altered miRNA expression showed that the majority of the affected biological pathways appeared to be associated to endothelial cell dysfunction and apoptosis. We found the expression of ten miRNAs (miR-26a-5p, -26b-5p, 29b-3p, -29c-3p, -125b-1-3p, -130b-3p, -140-5p, -192-5p, -221-3p and -320a) to increase gradually with increasing concentration of glucose. These miRNAs were also found to be involved in endothelial dysfunction. At least seven of them, miR-29b-3p, -29c-3p, -125b-1-3p, -130b-3p, -221-3p, -320a and -192-5p, can be correlated to endothelial cell apoptosis. PMID:27070575

  11. Sepsis-induced elevation in plasma serotonin facilitates endothelial hyperpermeability

    PubMed Central

    Li, Yicong; Hadden, Coedy; Cooper, Anthonya; Ahmed, Asli; Wu, Hong; Lupashin, Vladimir V.; Mayeux, Philip R.; Kilic, Fusun

    2016-01-01

    Hyperpermeability of the endothelial barrier and resulting microvascular leakage are a hallmark of sepsis. Our studies describe the mechanism by which serotonin (5-HT) regulates the microvascular permeability during sepsis. The plasma 5-HT levels are significantly elevated in mice made septic by cecal ligation and puncture (CLP). 5-HT-induced permeability of endothelial cells was associated with the phosphorylation of p21 activating kinase (PAK1), PAK1-dependent phosphorylation of vimentin (P-vimentin) filaments, and a strong association between P-vimentin and ve-cadherin. These findings were in good agreement with the findings with the endothelial cells incubated in serum from CLP mice. In vivo, reducing the 5-HT uptake rates with the 5-HT transporter (SERT) inhibitor, paroxetine blocked renal microvascular leakage and the decline in microvascular perfusion. Importantly, mice that lack SERT showed significantly less microvascular dysfunction after CLP. Based on these data, we propose that the increased endothelial 5-HT uptake together with 5-HT signaling disrupts the endothelial barrier function in sepsis. Therefore, regulating intracellular 5-HT levels in endothelial cells represents a novel approach in improving sepsis-associated microvascular dysfunction and leakage. These new findings advance our understanding of the mechanisms underlying cellular responses to intracellular/extracellular 5-HT ratio in sepsis and refine current views of these signaling processes during sepsis. PMID:26956613

  12. Sepsis-induced elevation in plasma serotonin facilitates endothelial hyperpermeability.

    PubMed

    Li, Yicong; Hadden, Coedy; Cooper, Anthonya; Ahmed, Asli; Wu, Hong; Lupashin, Vladimir V; Mayeux, Philip R; Kilic, Fusun

    2016-01-01

    Hyperpermeability of the endothelial barrier and resulting microvascular leakage are a hallmark of sepsis. Our studies describe the mechanism by which serotonin (5-HT) regulates the microvascular permeability during sepsis. The plasma 5-HT levels are significantly elevated in mice made septic by cecal ligation and puncture (CLP). 5-HT-induced permeability of endothelial cells was associated with the phosphorylation of p21 activating kinase (PAK1), PAK1-dependent phosphorylation of vimentin (P-vimentin) filaments, and a strong association between P-vimentin and ve-cadherin. These findings were in good agreement with the findings with the endothelial cells incubated in serum from CLP mice. In vivo, reducing the 5-HT uptake rates with the 5-HT transporter (SERT) inhibitor, paroxetine blocked renal microvascular leakage and the decline in microvascular perfusion. Importantly, mice that lack SERT showed significantly less microvascular dysfunction after CLP. Based on these data, we propose that the increased endothelial 5-HT uptake together with 5-HT signaling disrupts the endothelial barrier function in sepsis. Therefore, regulating intracellular 5-HT levels in endothelial cells represents a novel approach in improving sepsis-associated microvascular dysfunction and leakage. These new findings advance our understanding of the mechanisms underlying cellular responses to intracellular/extracellular 5-HT ratio in sepsis and refine current views of these signaling processes during sepsis.

  13. MicroRNAs in Hyperglycemia Induced Endothelial Cell Dysfunction.

    PubMed

    Silambarasan, Maskomani; Tan, Jun Rong; Karolina, Dwi Setyowati; Armugam, Arunmozhiarasi; Kaur, Charanjit; Jeyaseelan, Kandiah

    2016-01-01

    Hyperglycemia is closely associated with prediabetes and Type 2 Diabetes Mellitus. Hyperglycemia increases the risk of vascular complications such as diabetic retinopathy, diabetic nephropathy, peripheral vascular disease and cerebro/cardiovascular diseases. Under hyperglycemic conditions, the endothelial cells become dysfunctional. In this study, we investigated the miRNA expression changes in human umbilical vein endothelial cells exposed to different glucose concentrations (5, 10, 25 and 40 mM glucose) and at various time intervals (6, 12, 24 and 48 h). miRNA microarray analyses showed that there is a correlation between hyperglycemia induced endothelial dysfunction and miRNA expression. In silico pathways analyses on the altered miRNA expression showed that the majority of the affected biological pathways appeared to be associated to endothelial cell dysfunction and apoptosis. We found the expression of ten miRNAs (miR-26a-5p, -26b-5p, 29b-3p, -29c-3p, -125b-1-3p, -130b-3p, -140-5p, -192-5p, -221-3p and -320a) to increase gradually with increasing concentration of glucose. These miRNAs were also found to be involved in endothelial dysfunction. At least seven of them, miR-29b-3p, -29c-3p, -125b-1-3p, -130b-3p, -221-3p, -320a and -192-5p, can be correlated to endothelial cell apoptosis. PMID:27070575

  14. Endothelial cell tumor growth is Ape/ref-1 dependent.

    PubMed

    Biswas, Ayan; Khanna, Savita; Roy, Sashwati; Pan, Xueliang; Sen, Chandan K; Gordillo, Gayle M

    2015-09-01

    Tumor-forming endothelial cells have highly elevated levels of Nox-4 that release H2O2 into the nucleus, which is generally not compatible with cell survival. We sought to identify compensatory mechanisms that enable tumor-forming endothelial cells to survive and proliferate under these conditions. Ape-1/ref-1 (Apex-1) is a multifunctional protein that promotes DNA binding of redox-sensitive transcription factors, such as AP-1, and repairs oxidative DNA damage. A validated mouse endothelial cell (EOMA) tumor model was used to demonstrate that Nox-4-derived H2O2 causes DNA oxidation that induces Apex-1 expression. Apex-1 functions as a chaperone to keep transcription factors in a reduced state. In EOMA cells Apex-1 enables AP-1 binding to the monocyte chemoattractant protein-1 (mcp-1) promoter and expression of that protein is required for endothelial cell tumor formation. Intraperitoneal injection of the small molecule inhibitor E3330, which specifically targets Apex-1 redox-sensitive functions, resulted in a 50% decrease in tumor volume compared with mice injected with vehicle control (n = 6 per group), indicating that endothelial cell tumor proliferation is dependent on Apex-1 expression. These are the first reported results to establish Nox-4 induction of Apex-1 as a mechanism promoting endothelial cell tumor formation.

  15. Endothelial Dysfunction in Idiopathic Sudden Sensorineural Hearing Loss: A Review

    PubMed Central

    Quaranta, Nicola; De Ceglie, Vincenzo; D’Elia, Alessandra

    2016-01-01

    An endothelial dysfunction has been described in idiopathic sudden sensorineural hearing loss (ISSHL) patients. The purpose of our review was to: i) identify, evaluate and review recent research about cardiovascular risk factors involvement and signs of endothelial dysfunction in ISSHL; ii) implication of these discovering in clinical practice and future research. A Medline literature search was conducted to identify any study on the involvement of endothelial dysfunction in ISSHL, published in the English language in the last decade. The following MEDLINE search terms were used: sudden sensorineural hearing loss (SSHL) and endothelial dysfunction (text words). Additional studies were identified by hand searching the references of original articles and review articles. Studies were not excluded on the basis of the qualitative or quantitative definitions of SSHL, treatment regimens, or outcome measures. Data were extracted from included papers by a reviewer. Information on the patients, investigations, methods, interventions, and outcomes were systematically analyzed. Characteristics and results of all included studies were reviewed systematically. High levels of adhesion molecules, hyperhomocysteinemia and lower folate levels, unbalanced oxidative status, a lower value of flow-mediated dilatation of brachial artery and a reduced percentage of circulating endothelial progenitor cells in patients affected by ISSHL support the hypothesis that this syndrome should be considered as a microcirculation disorder based on endothelial dysfunction and drive clinicians to implement all the traditional strategies used for preventing cardiovascular events, to also reduce the likelihood of ISSHL occurrence. PMID:27588164

  16. 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

  17. Endothelial Dysfunction in Idiopathic Sudden Sensorineural Hearing Loss: A Review.

    PubMed

    Quaranta, Nicola; De Ceglie, Vincenzo; D'Elia, Alessandra

    2016-04-20

    An endothelial dysfunction has been described in idiopathic sudden sensorineural hearing loss (ISSHL) patients. The purpose of our review was to: i) identify, evaluate and review recent research about cardiovascular risk factors involvement and signs of endothelial dysfunction in ISSHL; ii) implication of these discovering in clinical practice and future research. A Medline literature search was conducted to identify any study on the involvement of endothelial dysfunction in ISSHL, published in the English language in the last decade. The following MEDLINE search terms were used: sudden sensorineural hearing loss (SSHL) and endothelial dysfunction (text words). Additional studies were identified by hand searching the references of original articles and review articles. Studies were not excluded on the basis of the qualitative or quantitative definitions of SSHL, treatment regimens, or outcome measures. Data were extracted from included papers by a reviewer. Information on the patients, investigations, methods, interventions, and outcomes were systematically analyzed. Characteristics and results of all included studies were reviewed systematically. High levels of adhesion molecules, hyperhomocysteinemia and lower folate levels, unbalanced oxidative status, a lower value of flow-mediated dilatation of brachial artery and a reduced percentage of circulating endothelial progenitor cells in patients affected by ISSHL support the hypothesis that this syndrome should be considered as a microcirculation disorder based on endothelial dysfunction and drive clinicians to implement all the traditional strategies used for preventing cardiovascular events, to also reduce the likelihood of ISSHL occurrence.

  18. Endothelial dysfunction correlates with decompression bubbles in rats.

    PubMed

    Zhang, Kun; Wang, Dong; Jiang, Zhongxin; Ning, Xiaowei; Buzzacott, Peter; Xu, Weigang

    2016-01-01

    Previous studies have documented that decompression led to endothelial dysfunction with controversial results. This study aimed to clarify the relationship between endothelial dysfunction, bubble formation and decompression rate. Rats were subjected to simulated air dives with one of four decompression rates: one slow and three rapid. Bubble formation was detected ultrasonically following decompression for two hours, before measurement of endothelial related indices. Bubbles were found in only rapid-decompressed rats and the amount correlated with decompression rate with significant variability. Serum levels of ET-1, 6-keto-PGF1α, ICAM-1, VCAM-1 and MDA, lung Wet/Dry weight ratio and histological score increased, serum NO decreased following rapid decompression. Endothelial-dependent vasodilatation to Ach was reduced in pulmonary artery rings among rapid-decompressed rats. Near all the above changes correlated significantly with bubble amounts. The results suggest that bubbles may be the causative agent of decompression-induced endothelial damage and bubble amount is of clinical significance in assessing decompression stress. Furthermore, serum levels of ET-1 and MDA may serve as sensitive biomarkers with the capacity to indicate endothelial dysfunction and decompression stress following dives. PMID:27615160

  19. Lack of vimentin impairs endothelial differentiation of embryonic stem cells

    PubMed Central

    Boraas, Liana C.; Ahsan, Tabassum

    2016-01-01

    The cytoskeletal filament vimentin is inherent to the endothelial phenotype and is critical for the proper function of endothelial cells in adult mice. It is unclear, however, if the presence of vimentin is necessary during differentiation to the endothelial phenotype. Here we evaluated gene and protein expression of differentiating wild type embryonic stem cells (WT ESCs) and vimentin knockout embryonic stem cells (VIM −/− ESCs) using embryoid bodies (EBs) formed from both cell types. Over seven days of differentiation VIM −/− EBs had altered morphology compared to WT EBs, with a rippled outer surface and a smaller size due to decreased proliferation. Gene expression of pluripotency markers decreased similarly for EBs of both cell types; however, VIM −/− EBs had impaired differentiation towards the endothelial phenotype. This was quantified with decreased expression of markers along the specification pathway, specifically the early mesodermal marker Brachy-T, the lateral plate mesodermal marker FLK1, and the endothelial-specific markers TIE2, PECAM, and VE-CADHERIN. Taken together, these results indicate that the absence of vimentin impairs spontaneous differentiation of ESCs to the endothelial phenotype in vitro. PMID:27480130

  20. Protein kinase D activity controls endothelial nitric oxide synthesis.

    PubMed

    Aicart-Ramos, Clara; Sánchez-Ruiloba, Lucía; Gómez-Parrizas, Mónica; Zaragoza, Carlos; Iglesias, Teresa; Rodríguez-Crespo, Ignacio

    2014-08-01

    Vascular endothelial growth factor (VEGF) regulates key functions of the endothelium, such as angiogenesis or vessel repair in processes involving endothelial nitric oxide synthase (eNOS) activation. One of the effector kinases that become activated in endothelial cells upon VEGF treatment is protein kinase D (PKD). Here, we show that PKD phosphorylates eNOS, leading to its activation and a concomitant increase in NO synthesis. Using mass spectrometry, we show that the purified active kinase specifically phosphorylates recombinant eNOS on Ser1179. Treatment of endothelial cells with VEGF or phorbol 12,13-dibutyrate (PDBu) activates PKD and increases eNOS Ser1179 phosphorylation. In addition, pharmacological inhibition of PKD and gene silencing of both PKD1 and PKD2 abrogate VEGF signaling, resulting in a clear diminished migration of endothelial cells in a wound healing assay. Finally, inhibition of PKD in mice results in an almost complete disappearance of the VEGF-induced vasodilatation, as monitored through determination of the diameter of the carotid artery. Hence, our data indicate that PKD is a new regulatory kinase of eNOS in endothelial cells whose activity orchestrates mammalian vascular tone. PMID:24928905

  1. Endothelial dysfunction and angiogenesis in autosomal dominant polycystic kidney disease.

    PubMed

    Fick-Brosnahan, Godela M

    2013-02-01

    Autosomal dominant polycystic kidney disease (ADPKD) is the most common potentially lethal hereditary disease. The hall mark of the disease is the development of innumerable cysts in kidneys and liver. However, a vascular phenotype including the early occurrence of hypertension, abnormalities in renal blood flow, intracranial and aortic aneurysms, spontaneous coronary and cervicocephalic artery dissections, and dolichoectasias of intracranial arteries is also part of the spectrum of ADPKD. While endothelial dysfunction occurs early in ADPKD and precedes the onset of hypertension, the pathogenesis of endothelial dysfunction has not been extensively studied. Development of endothelial dysfunction in ADPKD (as in other conditions characterized by endothelial dysfunction) has been linked to oxidative stress and vascular inflammation. Vascular dysfunction with increased contraction and decreased relaxation causes downstream tissue ischemia, a potent stimulus for angiogenesis. Evidence of angiogenesis on the surface of renal cysts has been documented in human ADPKD. In addition, high levels of angiogenic growth factors including vascular endothelial growth factor have been reported in cyst fluid and in the circulation of patients with ADPKD. In the following chapter we summarize recent studies examining the role and pathogenesis of endothelial dysfunction and neoangiogenesis in ADPKD. PMID:23971642

  2. Endothelial dysfunction correlates with decompression bubbles in rats

    PubMed Central

    Zhang, Kun; Wang, Dong; Jiang, Zhongxin; Ning, Xiaowei; Buzzacott, Peter; Xu, Weigang

    2016-01-01

    Previous studies have documented that decompression led to endothelial dysfunction with controversial results. This study aimed to clarify the relationship between endothelial dysfunction, bubble formation and decompression rate. Rats were subjected to simulated air dives with one of four decompression rates: one slow and three rapid. Bubble formation was detected ultrasonically following decompression for two hours, before measurement of endothelial related indices. Bubbles were found in only rapid-decompressed rats and the amount correlated with decompression rate with significant variability. Serum levels of ET-1, 6-keto-PGF1α, ICAM-1, VCAM-1 and MDA, lung Wet/Dry weight ratio and histological score increased, serum NO decreased following rapid decompression. Endothelial-dependent vasodilatation to Ach was reduced in pulmonary artery rings among rapid-decompressed rats. Near all the above changes correlated significantly with bubble amounts. The results suggest that bubbles may be the causative agent of decompression–induced endothelial damage and bubble amount is of clinical significance in assessing decompression stress. Furthermore, serum levels of ET-1 and MDA may serve as sensitive biomarkers with the capacity to indicate endothelial dysfunction and decompression stress following dives. PMID:27615160

  3. Endothelial Dysfunction in Idiopathic Sudden Sensorineural Hearing Loss: A Review.

    PubMed

    Quaranta, Nicola; De Ceglie, Vincenzo; D'Elia, Alessandra

    2016-04-20

    An endothelial dysfunction has been described in idiopathic sudden sensorineural hearing loss (ISSHL) patients. The purpose of our review was to: i) identify, evaluate and review recent research about cardiovascular risk factors involvement and signs of endothelial dysfunction in ISSHL; ii) implication of these discovering in clinical practice and future research. A Medline literature search was conducted to identify any study on the involvement of endothelial dysfunction in ISSHL, published in the English language in the last decade. The following MEDLINE search terms were used: sudden sensorineural hearing loss (SSHL) and endothelial dysfunction (text words). Additional studies were identified by hand searching the references of original articles and review articles. Studies were not excluded on the basis of the qualitative or quantitative definitions of SSHL, treatment regimens, or outcome measures. Data were extracted from included papers by a reviewer. Information on the patients, investigations, methods, interventions, and outcomes were systematically analyzed. Characteristics and results of all included studies were reviewed systematically. High levels of adhesion molecules, hyperhomocysteinemia and lower folate levels, unbalanced oxidative status, a lower value of flow-mediated dilatation of brachial artery and a reduced percentage of circulating endothelial progenitor cells in patients affected by ISSHL support the hypothesis that this syndrome should be considered as a microcirculation disorder based on endothelial dysfunction and drive clinicians to implement all the traditional strategies used for preventing cardiovascular events, to also reduce the likelihood of ISSHL occurrence. PMID:27588164

  4. Lack of vimentin impairs endothelial differentiation of embryonic stem cells.

    PubMed

    Boraas, Liana C; Ahsan, Tabassum

    2016-01-01

    The cytoskeletal filament vimentin is inherent to the endothelial phenotype and is critical for the proper function of endothelial cells in adult mice. It is unclear, however, if the presence of vimentin is necessary during differentiation to the endothelial phenotype. Here we evaluated gene and protein expression of differentiating wild type embryonic stem cells (WT ESCs) and vimentin knockout embryonic stem cells (VIM -/- ESCs) using embryoid bodies (EBs) formed from both cell types. Over seven days of differentiation VIM -/- EBs had altered morphology compared to WT EBs, with a rippled outer surface and a smaller size due to decreased proliferation. Gene expression of pluripotency markers decreased similarly for EBs of both cell types; however, VIM -/- EBs had impaired differentiation towards the endothelial phenotype. This was quantified with decreased expression of markers along the specification pathway, specifically the early mesodermal marker Brachy-T, the lateral plate mesodermal marker FLK1, and the endothelial-specific markers TIE2, PECAM, and VE-CADHERIN. Taken together, these results indicate that the absence of vimentin impairs spontaneous differentiation of ESCs to the endothelial phenotype in vitro. PMID:27480130

  5. Activated Brain Endothelial Cells Cross-Present Malaria Antigen

    PubMed Central

    Howland, Shanshan W.; Poh, Chek Meng; Rénia, Laurent

    2015-01-01

    In the murine model of cerebral malaria caused by P. berghei ANKA (PbA), parasite-specific CD8+ T cells directly induce pathology and have long been hypothesized to kill brain endothelial cells that have internalized PbA antigen. We previously reported that brain microvessel fragments from infected mice cross-present PbA epitopes, using reporter cells transduced with epitope-specific T cell receptors. Here, we confirm that endothelial cells are the population responsible for cross-presentation in vivo, not pericytes or microglia. PbA antigen cross-presentation by primary brain endothelial cells in vitro confers susceptibility to killing by CD8+ T cells from infected mice. IFNγ stimulation is required for brain endothelial cross-presentation in vivo and in vitro, which occurs by a proteasome- and TAP-dependent mechanism. Parasite strains that do not induce cerebral malaria were phagocytosed and cross-presented less efficiently than PbA in vitro. The main source of antigen appears to be free merozoites, which were avidly phagocytosed. A human brain endothelial cell line also phagocytosed P. falciparum merozoites. Besides being the first demonstration of cross-presentation by brain endothelial cells, our results suggest that interfering with merozoite phagocytosis or antigen processing may be effective strategies for cerebral malaria intervention. PMID:26046849

  6. Rapid homogeneous endothelialization of high aspect ratio microvascular networks.

    PubMed

    Naik, Nisarga; Hanjaya-Putra, Donny; Haller, Carolyn A; Allen, Mark G; Chaikof, Elliot L

    2015-08-01

    Microvascularization of an engineered tissue construct is necessary to ensure the nourishment and viability of the hosted cells. Microvascular constructs can be created by seeding the luminal surfaces of microfluidic channel arrays with endothelial cells. However, in a conventional flow-based system, the uniformity of endothelialization of such an engineered microvascular network is constrained by mass transfer of the cells through high length-to-diameter (L/D) aspect ratio microchannels. Moreover, given the inherent limitations of the initial seeding process to generate a uniform cell coating, the large surface-area-to-volume ratio of microfluidic systems demands long culture periods for the formation of confluent cellular microconduits. In this report, we describe the design of polydimethylsiloxane (PDMS) and poly(glycerol sebacate) (PGS) microvascular constructs with reentrant microchannels that facilitates rapid, spatially homogeneous endothelial cell seeding of a high L/D (2 cm/35 μm; > 550:1) aspect ratio microchannels. MEMS technology was employed for the fabrication of a monolithic, elastomeric, reentrant microvascular construct. Isotropic etching and PDMS micromolding yielded a near-cylindrical microvascular channel array. A 'stretch - seed - seal' operation was implemented for uniform incorporation of endothelial cells along the entire microvascular area of the construct yielding endothelialized microvascular networks in less than 24 h. The feasibility of this endothelialization strategy and the uniformity of cellularization were established using confocal microscope imaging. PMID:26227213

  7. Rapid homogeneous endothelialization of high aspect ratio microvascular networks.

    PubMed

    Naik, Nisarga; Hanjaya-Putra, Donny; Haller, Carolyn A; Allen, Mark G; Chaikof, Elliot L

    2015-08-01

    Microvascularization of an engineered tissue construct is necessary to ensure the nourishment and viability of the hosted cells. Microvascular constructs can be created by seeding the luminal surfaces of microfluidic channel arrays with endothelial cells. However, in a conventional flow-based system, the uniformity of endothelialization of such an engineered microvascular network is constrained by mass transfer of the cells through high length-to-diameter (L/D) aspect ratio microchannels. Moreover, given the inherent limitations of the initial seeding process to generate a uniform cell coating, the large surface-area-to-volume ratio of microfluidic systems demands long culture periods for the formation of confluent cellular microconduits. In this report, we describe the design of polydimethylsiloxane (PDMS) and poly(glycerol sebacate) (PGS) microvascular constructs with reentrant microchannels that facilitates rapid, spatially homogeneous endothelial cell seeding of a high L/D (2 cm/35 μm; > 550:1) aspect ratio microchannels. MEMS technology was employed for the fabrication of a monolithic, elastomeric, reentrant microvascular construct. Isotropic etching and PDMS micromolding yielded a near-cylindrical microvascular channel array. A 'stretch - seed - seal' operation was implemented for uniform incorporation of endothelial cells along the entire microvascular area of the construct yielding endothelialized microvascular networks in less than 24 h. The feasibility of this endothelialization strategy and the uniformity of cellularization were established using confocal microscope imaging.

  8. Endothelial Gata5 transcription factor regulates blood pressure

    PubMed Central

    Messaoudi, Smail; He, Ying; Gutsol, Alex; Wight, Andrew; Hébert, Richard L.; Vilmundarson, Ragnar O.; Makrigiannis, Andrew P.; Chalmers, John; Hamet, Pavel; Tremblay, Johanne; McPherson, Ruth; Stewart, Alexandre F. R.; Touyz, Rhian M.; Nemer, Mona

    2015-01-01

    Despite its high prevalence and economic burden, the aetiology of human hypertension remains incompletely understood. Here we identify the transcription factor GATA5, as a new regulator of blood pressure (BP). GATA5 is expressed in microvascular endothelial cells and its genetic inactivation in mice (Gata5-null) leads to vascular endothelial dysfunction and hypertension. Endothelial-specific inactivation of Gata5 mimics the hypertensive phenotype of the Gata5-null mice, suggestive of an important role for GATA5 in endothelial homeostasis. Transcriptomic analysis of human microvascular endothelial cells with GATA5 knockdown reveals that GATA5 affects several genes and pathways critical for proper endothelial function, such as PKA and nitric oxide pathways. Consistent with a role in human hypertension, we report genetic association of variants at the GATA5 locus with hypertension traits in two large independent cohorts. Our results unveil an unsuspected link between GATA5 and a prominent human condition, and provide a new animal model for hypertension. PMID:26617239

  9. Transient receptor potential channels and regulation of lung endothelial permeability

    PubMed Central

    2013-01-01

    Abstract This review highlights our current knowledge regarding expression of transient receptor potential (TRP) cation channels in lung endothelium and evidence for their involvement in regulation of lung endothelial permeability. Six mammalian TRP families have been identified and organized on the basis of sequence homology: TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPML (mucolipin), TRPP (polycystin), and TRPA (ankyrin). To date, only TRPC1/4, TRPC6, TRPV4, and TRPM2 have been extensively studied in lung endothelium. Calcium influx through each of these channels has been documented to increase lung endothelial permeability, although their channel-gating mechanisms, downstream signaling mechanisms, and impact on endothelial structure and barrier integrity differ. While other members of the TRPC, TRPV, and TRPM families may be expressed in lung endothelium, we have little or no evidence linking these to regulation of lung endothelial permeability. Further, neither the expression nor functional role(s) of any TRPML, TRPP, and TRPA family members has been studied in lung endothelium. In addition to this assessment organized by TRP channel family, we also discuss TRP channels and lung endothelial permeability from the perspective of lung endothelial heterogeneity, using outcomes of studies focused on TRPC1/4 and TRPV4 channels. The diversity within the TRP channel family and the relative paucity of information regarding roles of a number of these channels in lung endothelium make this field ripe for continued investigation. PMID:25006396

  10. Stereoselectivity of ectonucleotidases on vascular endothelial cells.

    PubMed Central

    Cusack, N J; Pearson, J D; Gordon, J L

    1983-01-01

    We have investigated the stereoselectivity of ectonucleotidases (nucleoside triphosphatase, EC 3.6.1.15; nucleoside diphosphatase, EC 3.6.1.6; 5'-nucleotidase, EC 3.1.3.5) on pig aortic endothelial cells using two classes of nucleotide analogue. In experiments with nucleotide enantiomers in which the natural D-ribofuranosyl moiety is replaced by an L-ribofuranosyl moiety, the rate of catabolism of 100 microM-L-ATP was one-fifth that of D-ATP, the rate of catabolism of 100 microM-L-ADP was one-fifteenth that of D-ADP and there was no detectable catabolism of 100 microM-L-AMP. Each of the L-enantiomers inhibited, apparently competitively, the catabolism of the corresponding D-enantiomer; Ki values were approx. 0.6 mM, 1.0 mM and 3.9 mM for L-ATP, L-ADP and L-AMP respectively. Experiments with adenosine 5'-[beta, gamma-imido]triphosphate and with D- and L-enantiomers of adenosine 5'-[beta, gamma-methylene]triphosphate revealed modest ectopyrophosphatase activity, undetectable in experiments with natural nucleotides, which was also stereoselective. Use of phosphorothioate nucleotide analogues demonstrated that ATP catabolism was virtually stereospecific with respect to the geometry of the thiol group substituted on the beta-phosphate: the Rp isomer was degraded, whereas there was little or no breakdown of the Sp isomer. ADP catabolism was also stereospecific with respect to the geometry of the thiol group substituted on the alpha-phosphate: the Sp isomer but not the Rp isomer was degraded. The geometry of thiol-group substitution on the alpha-phosphate had no effect on ATP catabolism to ADP. There was no detectable catabolism of analogues with thiol-group substitution on the terminal phosphate. Each of the phosphorothioate analogues that was catabolized broke down at a rate similar to that of the natural nucleotide from which it was derived. These results demonstrate that the ectonucleotidases on pig aortic endothelial cells exhibit a high degree of stereoselectivity

  11. Endothelial RAGE exacerbates acute postischaemic cardiac inflammation.

    PubMed

    Ziegler, Tilman; Horstkotte, Melanie; Lange, Philipp; Ng, Judy; Bongiovanni, Dario; Hinkel, Rabea; Laugwitz, Karl-Ludwig; Sperandio, Markus; Horstkotte, Jan; Kupatt, Christian

    2016-08-01

    Advanced glycation end-products (AGEs) interact with their receptor RAGE, leading to an inflammatory state. We investigated the role of RAGE in postischaemic leukocyte adhesion after myocardial infarction and its effect on postischaemic myocardial function. Wildtype (WT), ICAM-1-/-, RAGE-/- or ICAM-1/RAGE-/- mice underwent 20 minutes (min) of LAD-occlusion followed by 15 min of reperfusion. We applied in vivo fluorescence microscopy visualising Rhodamine-6G labelled leukocytes. To differentiate between endothelial and leukocyte RAGE, we generated bone marrow chimeric mice. Invasive hemodynamic measurements were performed in mice undergoing 45 min of myocardial ischaemia (via LAD-occlusion) followed by 24 hours of reperfusion. Left-ventricular developed pressure (LVDP) was assessed by insertion of a millar-tip catheter into the left ventricle. In the acute model of myocardial ischaemia, leukocyte retention (WT 68 ± 4 cells/hpf) was significantly reduced in ICAM-1-/- (40 ± 3 cells/hpf) and RAGE-/- mice (38 ± 4 cells/hpf). ICAM-1/RAGE-/- mice displayed an additive reduction of leukocyte retention (ICAM-1/RAGE-/- 15 ± 3 cells/hpf). Ly-6G+ neutrophil were predominantly reduced in ICAM-1/RAGE-/- hearts (28 %), whereas Ly-6C+ proinflammatory monocytes decreased to a lesser extent (55 %). Interestingly, PMN recruitment was not affected in chimeric mice with RAGE deficiency in BM cells (WT mice reconstituted with ICAM-1/RAGE-/- BM: 55 ± 4 cells/hpf) while in mice with global RAGE deficiency (ICAM-1/RAGE-/- mice reconstituted with ICAM-1/RAGE-/- BM) leucocyte retention was significantly reduced (13 ± 1 cells/hpf), similar to non-transplanted ICAM/RAGE-/- mice. Furthermore, postischaemic LVDP increased in ICAM-1/RAGE-/- animals (98 ± 4 mmHg vs 86 ± 4 mmHg in WT mice). In conclusion, combined deficiency of ICAM-1 and RAGE reduces leukocyte influx into infarcted myocardium and improves LV function during the acute phase after myocardial ischaemia and reperfusion

  12. Regulation of endothelial proliferation by the renin-angiotensin system in human umbilical vein endothelial cells.

    PubMed

    Herr, D; Rodewald, M; Fraser, H M; Hack, G; Konrad, R; Kreienberg, R; Wulff, C

    2008-07-01

    This study was performed in order to evaluate the role of angiotensin II in physiological angiogenesis. Human umbilical vein endothelial cells (HUVEC) were stained for angiotensin II type 1 receptor (AGTR1) immunocytochemically and for gene expression of renin-angiotensin system (RAS) components. The regulation of the angiogenesis-associated genes vascular endothelial growth factor (VEGF) and angiopoietins (ANGPT1 and ANGPT2) were studied using quantitative RT-PCR. Furthermore, we examined the effect of angiotensin II on the proliferation of HUVEC using Ki-67 as well as BrdU immunocytochemistry and investigated whether the administration of the AGTR1 blocker candesartan or the VEGF antagonist FLT1-Fc could suppress the observed angiotensin II-dependent proangiogenic effect. AGTR1 was expressed in HUVEC and the administration of angiotensin II significantly increased the gene expression of VEGF and decreased the gene expression of ANGPT1. Since the expression of ANGPT2 was not affected significantly the ratio of ANGPT1/ANGPT2 was decreased. In addition, a significantly increased endothelial cell proliferation was observed after stimulation with angiotensin II, which was suppressed by the simultaneous administration of candesartan or the VEGF antagonist FLT1-Fc. These results indicate the potential capacity of angiotensin II in influencing angiogenesis by the regulation of angiogenesis-associated genes via AGTR1. Since VEGF blockade opposed the effect of angiotensin II on cell proliferation, it is hypothesised that VEGF mediates the angiotensin II-dependent effect in concert with the changes in angiopoietin expression. This is the first report of the RAS on the regulation of angiogenesis-associated genes in physiology.

  13. Nitrones reverse hyperglycemia-induced endothelial dysfunction in bovine aortic endothelial cells.

    PubMed

    Headley, Colwyn A; DiSilvestro, David; Bryant, Kelsey E; Hemann, Craig; Chen, Chun-An; Das, Amlan; Ziouzenkova, Ouliana; Durand, Grégory; Villamena, Frederick A

    2016-03-15

    Hyperglycemia has been implicated in the development of endothelial dysfunction through heightened ROS production. Since nitrones reverse endothelial nitric oxide synthase (eNOS) dysfunction, increase antioxidant enzyme activity, and suppress pro-apoptotic signaling pathway and mitochondrial dysfunction from ROS-induced toxicity, the objective of this study was to determine whether nitrone spin traps DMPO, PBN and PBN-LA were effective at duplicating these effects and improving glucose uptake in an in vitro model of hyperglycemia-induced dysfunction using bovine aortic endothelial cells (BAEC). BAEC were cultured in DMEM medium with low (5.5mM glucose, LG) or high glucose (50mM, HG) for 14 days to model in vivo hyperglycemia as experienced in humans with metabolic disease. Improvements in cell viability, intracellular oxidative stress, NO and tetrahydrobiopterin (BH4)​ levels, mitochondrial membrane potential, glucose transport, and activity of antioxidant enzymes were measured from single treatment of BAEC with nitrones for 24h after hyperglycemia. Chronic hyperglycemia significantly increased intracellular ROS by 50%, decreased cell viability by 25%, reduced NO bioavailability by 50%, and decreased (BH4) levels by 15% thereby decreasing NO production. Intracellular glucose transport and superoxide dismutase (SOD) activity were also decreased by 50% and 25% respectively. Nitrone (PBN and DMPO, 50 μM) treatment of BAEC grown in hyperglycemic conditions resulted in the normalization of outcome measures except for SOD and catalase activities. Our findings demonstrate that the nitrones reverse the deleterious effects of hyperglycemia in BAEC. We believe that in vivo testing of these nitrone compounds in models of cardiometabolic disease is warranted.

  14. Nitrones reverse hyperglycemia-induced endothelial dysfunction in bovine aortic endothelial cells.

    PubMed

    Headley, Colwyn A; DiSilvestro, David; Bryant, Kelsey E; Hemann, Craig; Chen, Chun-An; Das, Amlan; Ziouzenkova, Ouliana; Durand, Grégory; Villamena, Frederick A

    2016-03-15

    Hyperglycemia has been implicated in the development of endothelial dysfunction through heightened ROS production. Since nitrones reverse endothelial nitric oxide synthase (eNOS) dysfunction, increase antioxidant enzyme activity, and suppress pro-apoptotic signaling pathway and mitochondrial dysfunction from ROS-induced toxicity, the objective of this study was to determine whether nitrone spin traps DMPO, PBN and PBN-LA were effective at duplicating these effects and improving glucose uptake in an in vitro model of hyperglycemia-induced dysfunction using bovine aortic endothelial cells (BAEC). BAEC were cultured in DMEM medium with low (5.5mM glucose, LG) or high glucose (50mM, HG) for 14 days to model in vivo hyperglycemia as experienced in humans with metabolic disease. Improvements in cell viability, intracellular oxidative stress, NO and tetrahydrobiopterin (BH4)​ levels, mitochondrial membrane potential, glucose transport, and activity of antioxidant enzymes were measured from single treatment of BAEC with nitrones for 24h after hyperglycemia. Chronic hyperglycemia significantly increased intracellular ROS by 50%, decreased cell viability by 25%, reduced NO bioavailability by 50%, and decreased (BH4) levels by 15% thereby decreasing NO production. Intracellular glucose transport and superoxide dismutase (SOD) activity were also decreased by 50% and 25% respectively. Nitrone (PBN and DMPO, 50 μM) treatment of BAEC grown in hyperglycemic conditions resulted in the normalization of outcome measures except for SOD and catalase activities. Our findings demonstrate that the nitrones reverse the deleterious effects of hyperglycemia in BAEC. We believe that in vivo testing of these nitrone compounds in models of cardiometabolic disease is warranted. PMID:26774452

  15. Synthesis of an endothelial cell mimicking surface containing thrombomodulin and endothelial protein C receptor

    NASA Astrophysics Data System (ADS)

    Kador, Karl Erich

    Synthetic materials for use in blood contacting applications have been studied for many years with limited success. One of the main areas of need for these materials is the design of synthetic vascular grafts for use in the hundreds of thousands of patients who have coronary artery bypass grafting, many without suitable veins for autologous grafts. The design of these grafts is constrained by two common modes of failure, the formation of intimal hyperplasia (IH) and thrombosis. IH formation has been previously linked to a mismatching of the mechanical properties of the graft and has been overcome by creating grafts using materials whose compliance mimics that of the native artery. Several techniques and surface modification have been designed to limit thrombosis on the surface of synthetic materials. One which has shown the greatest promise is the immobilization of Thrombomodulin (TM), a protein found on the endothelial cell membrane lining native blood vessels involved in the activation of the anticoagulant Protein C (PC). While TM immobilization has been shown to arrest thrombin formation and limit fibrous formations in in-vitro and in-vivo experiments, it has shown to be transport limiting under arterial flow. On the endothelial cell surface, TM is co-localized with Endothelial Protein C Receptor (EPCR), which increases PC transport onto the cell surface and increases PC activation via TM between 20-100 fold. This dissertation will describe the chemical modification of medical grade polyurethane (PU), whose compliance has been shown to match that of native arteries. This modification will enable the immobilization of two proteins on an enzymatically relevant scale estimated at less than 10 nm. This dissertation will further describe the immobilization of the proteins TM and EPCR, and analyze the ability of a surface co-immobilized with these proteins to activate the anticoagulant PC. Finally, it will compare the ability of this co-immobilized surface to delay

  16. A biphasic endothelial stress-survival mechanism regulates the cellular response to vascular endothelial growth factor A

    SciTech Connect

    Latham, Antony M.; Odell, Adam F.; Mughal, Nadeem A.; Issitt, Theo; Ulyatt, Clare; Walker, John H.; Homer-Vanniasinkam, Shervanthi; Ponnambalam, Sreenivasan

    2012-11-01

    Vascular endothelial growth factor A (VEGF-A) is an essential cytokine that regulates endothelial function and angiogenesis. VEGF-A binding to endothelial receptor tyrosine kinases such as VEGFR1 and VEGFR2 triggers cellular responses including survival, proliferation and new blood vessel sprouting. Increased levels of a soluble VEGFR1 splice variant (sFlt-1) correlate with endothelial dysfunction in pathologies such as pre-eclampsia; however the cellular mechanism(s) underlying the regulation and function of sFlt-1 are unclear. Here, we demonstrate the existence of a biphasic stress response in endothelial cells, using serum deprivation as a model of endothelial dysfunction. The early phase is characterized by a high VEGFR2:sFlt-1 ratio, which is reversed in the late phase. A functional consequence is a short-term increase in VEGF-A-stimulated intracellular signaling. In the late phase, sFlt-1 is secreted and deposited at the extracellular matrix. We hypothesized that under stress, increased endothelial sFlt-1 levels reduce VEGF-A bioavailability: VEGF-A treatment induces sFlt-1 expression at the cell surface and VEGF-A silencing inhibits sFlt-1 anchorage to the extracellular matrix. Treatment with recombinant sFlt-1 inhibits VEGF-A-stimulated in vitro angiogenesis and sFlt-1 silencing enhances this process. In this response, increased VEGFR2 levels are regulated by the phosphatidylinositol-3-kinase and PKB/Akt signaling pathways and increased sFlt-1 levels by the ERK1/2 signaling pathway. We conclude that during serum withdrawal, cellular sensing of environmental stress modulates sFlt-1 and VEGFR2 levels, regulating VEGF-A bioavailability and ensuring cell survival takes precedence over cell proliferation and migration. These findings may underpin an important mechanism contributing to endothelial dysfunction in pathological states. -- Highlights: Black-Right-Pointing-Pointer Endothelial cells mount a stress response under conditions of low serum. Black

  17. Gene silencing of endothelial von Willebrand Factor attenuates angiotensin II-induced endothelin-1 expression in porcine aortic endothelial cells

    PubMed Central

    Dushpanova, Anar; Agostini, Silvia; Ciofini, Enrica; Cabiati, Manuela; Casieri, Valentina; Matteucci, Marco; Del Ry, Silvia; Clerico, Aldo; Berti, Sergio; Lionetti, Vincenzo

    2016-01-01

    Expression of endothelin (ET)-1 is increased in endothelial cells exposed to angiotensin II (Ang II), leading to endothelial dysfunction and cardiovascular disorders. Since von Willebrand Factor (vWF) blockade improves endothelial function in coronary patients, we hypothesized that targeting endothelial vWF with short interference RNA (siRNA) prevents Ang II-induced ET-1 upregulation. Nearly 65 ± 2% silencing of vWF in porcine aortic endothelial cells (PAOECs) was achieved with vWF-specific siRNA without affecting cell viability and growth. While showing ET-1 similar to wild type cells at rest, vWF-silenced cells did not present ET-1 upregulation during exposure to Ang II (100 nM/24 h), preserving levels of endothelial nitric oxide synthase activity similar to wild type. vWF silencing prevented AngII-induced increase in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity and superoxide anion (O2−) levels, known triggers of ET-1 expression. Moreover, no increase in O2− or ET-1 levels was found in silenced cells treated with AngII or NOX-agonist phorbol ester (PMA 5 nM/48 h). Finally, vWF was required for overexpression of NOX4 and NOX2 in response to AngII and PMA. In conclusion, endothelial vWF knockdown prevented Ang II-induced ET-1 upregulation through attenuation of NOX-mediated O2− production. Our findings reveal a new role of vWF in preventing of Ang II-induced endothelial dysfunction. PMID:27443965

  18. Platelet endothelial cell adhesion molecule-1 modulates endothelial cell motility through the small G-protein Rho.

    PubMed

    Gratzinger, Dita; Canosa, Sandra; Engelhardt, Britta; Madri, Joseph A

    2003-08-01

    Platelet endothelial cell adhesion molecule-1 (PECAM-1), an immunoglobulin family vascular adhesion molecule, is involved in endothelial cell migration and angiogenesis (1, 2). We found that endothelial cells lacking PECAM-1 exhibit increased single cell motility and extension formation but poor wound healing migration, reminiscent of cells in which Rho activity has been suppressed by overexpressing a GTPase-activating protein (3). The ability of PECAM-1 to restore wound healing migration to PECAM-1-deficient cells was independent of its extracellular domain or signaling via its immunoreceptor tyrosine-based inhibitory motif. PECAM-1-deficient endothelial cells had a selective defect in RhoGTP loading, and inhibition of Rho activity mimicked the PECAM-1-deficient phenotype of increased chemokinetic single cell motility at the expense of coordinated wound healing migration. The wound healing advantage of PECAM-1-positive endothelial cells was not only Rho mediated but pertussis toxin inhibitable, characteristic of migration mediated by heterotrimeric G-protein-linked seven-transmembrane receptor signaling such as signaling in response to the serum sphingolipid sphingosine-1-phosphate (S1P) (4, 5). Indeed, we found that the wound healing defect of PECAM-1 null endothelial cells is minimized in sphingolipid-depleted media; moreover, PECAM-1 null endothelial cells fail to increase their migration in response to S1P. We have also found that PECAM-1 localizes to rafts and that in its absence heterotrimeric G-protein components are differentially recruited to rafts, providing a potential mechanism for PECAM-1-mediated coordination of S1P signaling. PECAM-1 may thus support the effective S1P/RhoGTP signaling required for wound healing endothelial migration by allowing for the spatially directed, coordinated activation of Galpha signaling pathways. PMID:12890700

  19. The mechanics of endothelial gap formation

    NASA Astrophysics Data System (ADS)

    Chattoraj, Joyjit; Del Gado, Emanuela; Hardin, C. Corey; Krishnan, Ramaswamy

    The vascular endothelium is a layer of specialized cells, referred to as endothelial cells (EC) that line the internal surfaces of blood vessels and are largely responsible for regulating the transit of fluids, solutes and immune system cells from the circulation, across the vessel wall, and into the tissues. We investigate the physics of the mechanical events that may proceed and eventually lead to dramatic increase of its permeability, leading to serious illness. In combination with experiments measuring local stresses and gap formation in EC in different conditions, we devise a minimal model based on an amorphous assembly of adhesive particles, subjected to an imposed tension. Numerical simulations of the model show that, as a function of the rate at which the tension is imposed, the system goes from an elastic regime in which small gaps increase in number to a ``plastic'' one, where pre-existing gaps increase in size, and internal stresses display large hetereogeneities and long range correlations. This second regime bears intriguing similarities with the experimental finding in EC monolayers.

  20. Tetrahydrobiopterin restores endothelial function in hypercholesterolemia.

    PubMed Central

    Stroes, E; Kastelein, J; Cosentino, F; Erkelens, W; Wever, R; Koomans, H; Lüscher, T; Rabelink, T

    1997-01-01

    In hypercholesterolemia, impaired nitric oxide activity has been associated with increased nitric oxide degradation by oxygen radicals. Deficiency of tetrahydrobiopterin, an essential cofactor of nitric oxide synthase, causes both impaired nitric oxide activity and increased oxygen radical formation. In this study we tested whether tetrahydrobiopterin deficiency contributes to the decreased nitric oxide activity observed in hypercholesterolemic patients. Therefore, L-mono-methyl-arginine to inhibit basal nitric oxide activity, serotonin to stimulate nitric oxide activity, and nitroprusside as endothelium-independent vasodilator were infused in the brachial artery of 13 patients with familial hypercholesterolemia and 13 matched controls. The infusions were repeated during coinfusion of L-arginine (200 microg/kg/min), tetrahydrobiopterin (500 microg/min), or the combination of both compounds. Forearm vasomotion was assessed using forearm venous occlusion plethysmography and expressed as ratio of blood flow between measurement and control arm (M/C ratio). Tetrahydrobiopterin infusion alone did not alter M/C ratio. Both the attenuated L-mono-methyl-arginine-induced vasoconstriction as well as the impaired serotonin-induced vasodilation were restored in patients during tetrahydrobiopterin infusion. Tetrahydrobiopterin had no effect in controls. In conclusion, this study demonstrates restoration of endothelial dysfunction by tetrahydrobiopterin suppletion in hypercholesterolemic patients. PMID:9011574

  1. Immunological functions of liver sinusoidal endothelial cells

    PubMed Central

    Knolle, Percy A; Wohlleber, Dirk

    2016-01-01

    Liver sinusoidal endothelial cells (LSECs) line the liver sinusoids and separate passenger leukocytes in the sinusoidal lumen from hepatocytes. LSECs further act as a platform for adhesion of various liver-resident immune cell populations such as Kupffer cells, innate lymphoid cells or liver dendritic cells. In addition to having an extraordinary scavenger function, LSECs possess potent immune functions, serving as sentinel cells to detect microbial infection through pattern recognition receptor activation and as antigen (cross)-presenting cells. LSECs cross-prime naive CD8 T cells, causing their rapid differentiation into memory T cells that relocate to secondary lymphoid tissues and provide protection when they re-encounter the antigen during microbial infection. Cross-presentation of viral antigens by LSECs derived from infected hepatocytes triggers local activation of effector CD8 T cells and thereby assures hepatic immune surveillance. The immune function of LSECs complements conventional immune-activating mechanisms to accommodate optimal immune surveillance against infectious microorganisms while preserving the integrity of the liver as a metabolic organ. PMID:27041636

  2. Endothelial Thermotolerance Impairs Nanoparticle Transport in Tumors.

    PubMed

    Bagley, Alexander F; Scherz-Shouval, Ruth; Galie, Peter A; Zhang, Angela Q; Wyckoff, Jeffrey; Whitesell, Luke; Chen, Christopher S; Lindquist, Susan; Bhatia, Sangeeta N

    2015-08-15

    The delivery of diagnostic and therapeutic agents to solid tumors is limited by physical transport barriers within tumors, and such restrictions directly contribute to decreased therapeutic efficacy and the emergence of drug resistance. Nanomaterials designed to perturb the local tumor environment with precise spatiotemporal control have demonstrated potential to enhance drug delivery in preclinical models. Here, we investigated the ability of one class of heat-generating nanomaterials called plasmonic nanoantennae to enhance tumor transport in a xenograft model of ovarian cancer. We observed a temperature-dependent increase in the transport of diagnostic nanoparticles into tumors. However, a transient, reversible reduction in this enhanced transport was seen upon reexposure to heating, consistent with the development of vascular thermotolerance. Harnessing these observations, we designed an improved treatment protocol combining plasmonic nanoantennae with diffusion-limited chemotherapies. Using a microfluidic endothelial model and genetic tools to inhibit the heat-shock response, we found that the ability of thermal preconditioning to limit heat-induced cytoskeletal disruption is an important component of vascular thermotolerance. This work, therefore, highlights the clinical relevance of cellular adaptations to nanomaterials and identifies molecular pathways whose modulation could improve the exposure of tumors to therapeutic agents.

  3. Endothelial Surface Protrusion by a Point Force.

    PubMed

    Chen, Yong; Lu, Lan; Shao, Jin-Yu

    2016-03-01

    During leukocyte rolling on the endothelium, surface protrusion and membrane tether extraction occur consecutively on leukocytes. Both surface protrusion and tether extraction of leukocytes stabilize leukocyte rolling. Tethers can also be extracted from endothelial cells (ECs), but surface protrusion of ECs has never been confirmed to exist. In this study, we examined EC surface protrusion with the micropipette aspiration technique. We found that, like leukocytes, surface protrusion on an EC did exist when a point force was imposed. Both the protrusional stiffness and the crossover force of EC surface protrusion were dependent on the force loading rate and the cytoskeletal integrity, but neither of them was dependent on tumor necrosis factor α stimulation. Temperature (37°C) affected the protrusional stiffness only at small force loading rates. When a neutrophil was employed to directly impose the pulling force on the EC, simultaneous surface protrusion from both cells occurred, and it can be modeled as two springs connected in series, although the spring constants should be adjusted according to the force loading rate. Therefore, EC surface protrusion is an important aspect of leukocyte rolling, and it should not be ignored when leukocyte rolling stability is studied systematically.

  4. The endothelial function in cardiac surgery.

    PubMed

    Ranucci, M

    2006-06-01

    Cardiac operations with cardiopulmonary bypass exerts many different actions which modify the natural function of endothelial cells. The main determinant is the activation of the coagulation system both through the intrinsic and extrinsic pathways, leading to an overwhelming thrombin formation. To counteract the coagulant effects of thrombin, heparin is used in large doses. As a result, the endothelium is asked to promote all its anticoagulant properties, basically through the AT release from the surface, the tissue factor pathway inhibitor release, and the activation of the protein C protein S system. At the end of cardiac operations, all these systems are depleted, and low levels of antithrombin, tissue factor pathway inhibitor, protein C are available for further anticoagulant effects. There is the evidence that levels of antithrombin activity below 50% at the end of cardiac operations with cardiopulmonary bypass are associated to bad outcomes in terms of surgical revision rate, thromboembolic events, and neurological events. Exogenous antithrombin administration has a well defined action in limiting thrombin formation during cardiac operations; however, we are still lacking an evidence-based information about the clinical impact of this and others possible preventive strategies based on exogenous administration of antithrombin before or during cardiac operations. PMID:16682923

  5. Potential proinflammatory effects of hydroxyapatite nanoparticles on endothelial cells in a monocyte-endothelial cell coculture model.

    PubMed

    Liu, Xin; Sun, Jiao

    2014-01-01

    Currently, synthetic hydroxyapatite nanoparticles (HANPs) are used in nanomedicine fields. The delivery of nanomedicine to the bloodstream exposes the cardiovascular system to a potential threat. However, the possible adverse cardiovascular effects of HANPs remain unclear. Current observations using coculture models of endothelial cells and monocytes with HANPs to mimic the complex physiological functionality of the vascular system demonstrate that monocytes could play an important role in the mechanisms of endothelium dysfunction induced by the exposure to HANPs. Our transmission electron microscopy analysis revealed that both monocytes and endothelial cells could take up HANPs. Moreover, our findings demonstrated that at a subcytotoxic dose, HANPs alone did not cause direct endothelial cell injury, but they did induce an indirect activation of endothelial cells, resulting in increased interleukin-6 production and elevated adhesion molecule expression after coculture with monocytes. The potential proinflammatory effect of HANPs is largely mediated by the release of soluble factors from the activated monocytes, leading to an inflammatory response of the endothelium, which is possibly dependent on p38/c-Jun N-terminal kinase, and nuclear factor-kappa B signaling activation. The use of in vitro monocyte-endothelial cell coculture models for the biocompatibility assessment of HANPs could reveal their potential proinflammatory effects on endothelial cells, suggesting that exposure to HANPs possibly increases the risk of cardiovascular disease.

  6. Neuropilin2 expressed in gastric cancer endothelial cells increases the proliferation and migration of endothelial cells in response to VEGF

    SciTech Connect

    Kim, Woo Ho; Lee, Sun Hee; Jung, Myung Hwan; Seo, Ji Heun; Kim, Jin; Kim, Min A; Lee, You Mie

    2009-08-01

    The structure and characteristics of the tumor vasculature are known to be different from those of normal vessels. Neuropilin2 (Nrp2), which is expressed in non-endothelial cell types, such as neuronal or cancer cells, functions as a receptor for both semaphorin and vascular endothelial growth factor (VEGF). After isolating tumor and normal endothelial cells from advanced gastric cancer tissue and normal gastric mucosa tissues, respectively, we identified genes that were differentially expressed in gastric tumor endothelial (TEC) and normal endothelial cells (NEC) using DNA oligomer chips. Using reverse transcriptase-PCR, we confirmed the chip results by showing that Nrp2 gene expression is significantly up-regulated in TEC. Genes that were found to be up-regulated in TEC were also observed to be up-regulated in human umbilical vein endothelial cells (HUVECs) that were co-cultured with gastric cancer cells. In addition, HUVECs co-cultured with gastric cancer cells showed an increased reactivity to VEGF-induced proliferation and migration. Moreover, overexpression of Nrp2 in HUVECs significantly enhanced the proliferation and migration induced by VEGF. Observation of an immunohistochemical analysis of various human tumor tissue arrays revealed that Nrp2 is highly expressed in the tumor vessel lining and to a lesser extent in normal tissue microvessels. From these results, we suggest that Nrp2 may function to increase the response to VEGF, which is more significant in TEC than in NEC given the differential expression, leading to gastric TEC with aggressive angiogenesis phenotypes.

  7. Endothelial lipase is a major determinant of HDL level

    SciTech Connect

    Ishida, Tatsuro; Choi, Sungshin; Kundu, Ramendra K.; Hirata, Ken-Ichi; Rubin, Edward M.; Cooper, Allen D.; Quertermous, Thomas

    2003-01-30

    For the past three decades, epidemiologic studies have consistently demonstrated an inverse relationship between plasma HDL cholesterol (HDL-C) concentrations and coronary heart disease (CHD). Population-based studies have provided compelling evidence that low HDL-C levels are a risk factor for CHD, and several clinical interventions that increased plasma levels of HDL-C were associated with a reduction in CHD risk. These findings have stimulated extensive investigation into the determinants of plasma HDL-C levels. Turnover studies using radiolabeled apolipoprotein A-I, the major protein component of HDL, suggest that plasma HDL-C concentrations are highly correlated with the rate of clearance of apolipoprotein AI. However, the metabolic mechanisms by which HDL are catabolized have not been fully defined. Previous studies in humans with genetic deficiency of cholesteryl ester transfer protein, and in mice lacking the scavenger receptor BI (SR-BI), have demonstrated that these proteins participate in the removal of cholesterol from HDL, while observations in individuals with mutations in hepatic lipase indicate that this enzyme hydrolyzes HDL triglycerides. In this issue of the JCI, reports from laboratories of Tom Quertermous and Dan Rader now indicate that endothelial lipase (LIPG), a newly identified member of the lipase family, catalyzes the hydrolysis of HDL phospholipids and facilitates the clearance of HDL from the circulation. Endothelial lipase was initially cloned by both of these laboratories using entirely different strategies. Quertermous and his colleagues identified endothelial lipase as a transcript that was upregulated in cultured human umbilical vein endothelial cells undergoing tube formation, whereas the Rader group cloned endothelial lipase as a transcript that was upregulated in the human macrophage-like cell line THP-1 exposed to oxidized LDL. Database searches revealed that endothelial lipase shows strong sequence similarity to lipoprotein

  8. Marinobufagenin and cyclic strain may activate endothelial NADPH oxidase, contributing to the adverse impact of salty diets on vascular and cerebral health.

    PubMed

    McCarty, Mark F

    2012-02-01

    Limited but provocative ecologic epidemiology suggests that dietary salt may play a central role in the genesis of not only of stroke, but also dementia, including Alzheimer's disease. Impairment of nitric oxide bioactivity in the cerebral microvasculature is a likely mediator of this effect. Salted diets evoke increased adrenal secretion of the natriuretic steroid marinobufagenin (MBG), which promotes natriuresis via inhibition of renal tubular Na+/K+-ATPase; this effect is notably robust in salt-sensitive rodent strains in which other compensatory natriuretic mechanisms are subnormally efficient. MBG-mediated inhibition of sodium pumps in vascular smooth muscle likely plays a role in the hypertension induced by salty diets in these rodents. However, salt sensitivity in humans is associated with increased vascular mortality and ventricular hypertrophy independent of blood pressure; this suggests that MBG may be pathogenic via mechanisms unrelated to blood pressure control. Indeed, recent evidence indicates that MBG, via interaction with alpha1 isoforms of the sodium pump, can activate various intracellular signaling pathways at physiological concentrations too low to notably inhibit pump activity. An overview of current evidence suggests the hypothesis that MBG - as well as the cyclic strain induced by hypertension per se - may induce endothelial oxidative stress by activating NADPH oxidase. If so, this could rationalize the increase in vascular and systemic oxidative stress observed in salt-sensitive rodents fed salty diets, or in rodents infused with MBG; moreover, if this effect is a particularly prominent determinant of oxidative stress in cerebrovascular endothelium, it might help to explain the virtual absence of stroke and dementia in low-salt societies. As a corollary of this hypothesis, it can be predicted that spirulina-derived phycobilins, which appear to mimic the physiological role of bilirubin as an inhibitor of NAPDH oxidase complexes, may have

  9. A dual role for endothelial cells in cytomegalovirus infection? A study of cytomegalovirus infection in a series of rat endothelial cell lines.

    PubMed

    Vossen, R C; Derhaag, J G; Slobbe-van Drunen, M E; Duijvestijn, A M; van Dam-Mieras, M C; Bruggeman, C A

    1996-12-01

    Several clinical findings point to the involvement of microvascular endothelial cells in cytomegalovirus-related pathology. In this study the interactions of cytomegalovirus (CMV) with microvascular endothelial cells was investigated in an in vitro rat model. A series of rat endothelial cell lines, considered representative for the heterogeneity of heart microvascular endothelium in vivo, were infected with rat CMV (RCMV). The course of infection and production of infectious virus were examined using immunofluorescence staining and plaque titration assays, and was compared with infection of fully permissive rat fibroblasts. These endothelial cell lines displayed differences in susceptibility to CMV infection. Two endothelial cell lines (RHEC 50 and 191) were practically non-permissive, while four endothelial cell lines (RHEC 3, 10, 11 and 116) were partly permissive for CMV infection. In contrast to CMV infection in fibroblasts, only limited infection of the permissive endothelial cell lines was observed without spreading of CMV infection through the monolayer, although infectious virus was produced. Detachment of infected endothelial cells and recovery of the monolayer with time was observed. The detached endothelial cells were able to transmit CMV infection to fibroblast monolayers, but not to endothelial monolayers. Our in vitro results demonstrate differences in permissiveness for RCMV between the series of rat endothelial cell lines, which is suggestive for endothelial heterogeneity to CMV infection in vivo. Our findings indicate that endothelial cells are relatively resistant to CMV infection and that, upon infection, the endothelial monolayer may dispose of the virus via detachment of the infected cells. This points to a dual role for the endothelium in CMV infection in vivo: a barrier for CMV infection (by the endothelial monolayer) on the one hand and spreading of CMV infection (by detached infected cells) on the other hand.

  10. Effect of Polyelectrolyte Film Stiffness on Endothelial Cells During Endothelial-to-Mesenchymal Transition.

    PubMed

    Zhang, He; Chang, Hao; Wang, Li-mei; Ren, Ke-feng; Martins, M Cristina L; Barbosa, Mário A; Ji, Jian

    2015-11-01

    Endothelial-to-mesenchymal transition (EndMT), during which endothelial cells (ECs) transdifferentiate into mesenchymal phenotype, plays a key role in the development of vascular implant complications such as endothelium dysfunction and in-stent restenosis. Substrate stiffness has been confirmed as a key factor to influence EC behaviors; however, so far, the relationship between substrate stiffness and EndMT has been rarely studied. Here, ECs were cultured on the (poly(L-lysine)/hyaluronate acid) (PLL/HA) multilayer films with controlled stiffness for 2 weeks, and their EndMT behaviors were studied. We demonstrated that ECs lost their markers (vWf and CD31) in a stiffness-dependent manner even without supplement of growth factors, and the softer film favored the maintaining of EC phenotype. Further, induced by transforming growth factor β1 (TGF-β1), ECs underwent EndMT, as characterized by losing their typical cobblestone morphology and markers and gaining smooth muscle cell markers (α-smooth muscle actin and calponin). Interestingly, stronger EndMT was observed when ECs were cultured on the stiffer film. Collectively, our findings suggest that substrate stiffness has significant effects on EndMT, and a softer substrate is beneficial to ECs by keeping their phenotype and inhibiting EndMT, which presents a new strategy for surface design of vascular implant materials. PMID:26477358

  11. Acetylbritannilactone Modulates Vascular Endothelial Growth Factor Signaling and Regulates Angiogenesis in Endothelial Cells

    PubMed Central

    Zhao, Jingshan; Niu, Honglin; Li, Aiying; Nie, Lei

    2016-01-01

    The present study was conducted to determine the effects of 1-O-acetylbritannilactone (ABL), a compound extracted from Inula britannica L., on vascular endothelial growth factor (VEGF) signaling and angiogenesis in endothelial cells (ECs). We showed that ABL promotes VEGF-induced cell proliferation, growth, migration, and tube formation in cultured human ECs. Furthermore, the modulatory effect of ABL on VEGF-induced Akt, MAPK p42/44, and p38 phosphorylation, as well as on upstream VEGFR-2 phosphorylation, were associated with VEGF-dependent Matrigel angiogenesis in vivo. In addition, animals treated with ABL (26 mg/kg/day) recovered blood flow significantly earlier than control animals, suggesting that ABL affects ischemia-mediated angiogenesis and arteriogenesis in vivo. Finally, we demonstrated that ABL strongly reduced the levels of VEGFR-2 on the cell surface, enhanced VEGFR-2 endocytosis, which consistent with inhibited VE-cadherin, a negative regulator of VEGF signaling associated with VEGFR-2 complex formation, but did not alter VE-cadherin or VEGFR-2 expression in ECs. Our results suggest that ABL may serve as a novel therapeutic intervention for various cardiovascular diseases, including chronic ischemia, by regulating VEGF signaling and modulating angiogenesis. PMID:26863518

  12. The Novel Methods for Analysis of Exosomes Released from Endothelial Cells and Endothelial Progenitor Cells

    PubMed Central

    Wang, Jinju; Guo, Runmin; Yang, Yi; Jacobs, Bradley; Chen, Suhong; Iwuchukwu, Ifeanyi; Gaines, Kenneth J.; Chen, Yanfang; Simman, Richard; Lv, Guiyuan; Wu, Keng; Bihl, Ji C.

    2016-01-01

    Exosomes (EXs) are cell-derived vesicles that mediate cell-cell communication and could serve as biomarkers. Here we described novel methods for purification and phenotyping of EXs released from endothelial cells (ECs) and endothelial progenitor cells (EPCs) by combining microbeads and fluorescence quantum dots (Q-dots®) techniques. EXs from the culture medium of ECs and EPCs were isolated and detected with cell-specific antibody conjugated microbeads and second antibody conjugated Q-dots by using nanoparticle tracking analysis (NTA) system. The sensitivities of the cell origin markers for ECs (CD105, CD144) and EPCs (CD34, KDR) were evaluated. The sensitivity and specificity were determined by using positive and negative markers for EXs (CD63), platelets (CD41), erythrocytes (CD235a), and microvesicles (Annexin V). Moreover, the methods were further validated in particle-free plasma and patient samples. Results showed that anti-CD105/anti-CD144 and anti-CD34/anti-KDR had the highest sensitivity and specificity for isolating and detecting EC-EXs and EPC-EXs, respectively. The methods had the overall recovery rate of over 70% and were able to detect the dynamical changes of circulating EC-EXs and EPC-EXs in acute ischemic stroke. In conclusion, we have developed sensitive and specific microbeads/Q-dots fluorescence NTA methods for EC-EX and EPC-EX isolation and detection, which will facilitate the functional study and biomarker discovery. PMID:27118976

  13. The Novel Methods for Analysis of Exosomes Released from Endothelial Cells and Endothelial Progenitor Cells.

    PubMed

    Wang, Jinju; Guo, Runmin; Yang, Yi; Jacobs, Bradley; Chen, Suhong; Iwuchukwu, Ifeanyi; Gaines, Kenneth J; Chen, Yanfang; Simman, Richard; Lv, Guiyuan; Wu, Keng; Bihl, Ji C

    2016-01-01

    Exosomes (EXs) are cell-derived vesicles that mediate cell-cell communication and could serve as biomarkers. Here we described novel methods for purification and phenotyping of EXs released from endothelial cells (ECs) and endothelial progenitor cells (EPCs) by combining microbeads and fluorescence quantum dots (Q-dots®) techniques. EXs from the culture medium of ECs and EPCs were isolated and detected with cell-specific antibody conjugated microbeads and second antibody conjugated Q-dots by using nanoparticle tracking analysis (NTA) system. The sensitivities of the cell origin markers for ECs (CD105, CD144) and EPCs (CD34, KDR) were evaluated. The sensitivity and specificity were determined by using positive and negative markers for EXs (CD63), platelets (CD41), erythrocytes (CD235a), and microvesicles (Annexin V). Moreover, the methods were further validated in particle-free plasma and patient samples. Results showed that anti-CD105/anti-CD144 and anti-CD34/anti-KDR had the highest sensitivity and specificity for isolating and detecting EC-EXs and EPC-EXs, respectively. The methods had the overall recovery rate of over 70% and were able to detect the dynamical changes of circulating EC-EXs and EPC-EXs in acute ischemic stroke. In conclusion, we have developed sensitive and specific microbeads/Q-dots fluorescence NTA methods for EC-EX and EPC-EX isolation and detection, which will facilitate the functional study and biomarker discovery.

  14. Crosstalk between cancer cells and blood endothelial and lymphatic endothelial cells in tumour and organ microenvironment

    PubMed Central

    Lee, Esak; Pandey, Niranjan B.; Popel, Aleksander S.

    2015-01-01

    Tumour and organ microenvironments are crucial for cancer progression and metastasis. Crosstalk between multiple non-malignant cell types in the microenvironments and cancer cells promotes tumour growth and metastasis. Blood and lymphatic endothelial cells (BEC and LEC) are two of the components in the microenvironments. Tumour blood vessels (BV), comprising BEC, serve as conduits for blood supply into the tumour, and are important for tumour growth as well as haematogenous tumour dissemination. Lymphatic vessels (LV), comprising LEC, which are relatively leaky compared with BV, are essential for lymphogenous tumour dissemination. In addition to describing the conventional roles of the BV and LV, we also discuss newly emerging roles of these endothelial cells: their crosstalk with cancer cells via molecules secreted by the BEC and LEC (also called angiocrine and lymphangiocrine factors). This review suggests that BEC and LEC in various microenvironments can be orchestrators of tumour progression and proposes new mechanism-based strategies to discover new therapies to supplement conventional anti-angiogenic and anti-lymphangiogenic therapies. PMID:25634527

  15. Endothelial retention and phenotype on carbonized cardiovascular implant surfaces

    PubMed Central

    Frendl, Chris; Tucker, Scott; Khan, Nadeem; Esch, Mandy; Kanduru, Shrinidhi; Cao, Thong M.; García, Andrés J.; King, Michael R.; Butcher, Jonathan T.

    2014-01-01

    Heart valve disease is an increasing clinical burden for which there is no effective treatment outside of prosthetic replacement. Over the last 20 years, clinicians have increasingly preferred the use of biological prosthetics to mechanical valves despite their superior durability because of the lifelong anticoagulation therapy that is required. Mechanical valve surface engineering has largely focused on being as non-thrombogenic as possible, but despite decades of iteration has had insufficient impact on the anticoagulation burden. In this study, we systematically evaluate the potential for endothelialization of the pyrolytic carbon surface used in mechanical valves. We compared adsorbed adhesion ligand type (collagen I, fibronectin, laminin, and purified adhesion domain fragments GFOGER and FN7-10) and concentration on endothelial adhesion rates and adhesion strength on Medtronic-Hall prosthetic valve surfaces. Regardless of ligand type or concentration, endothelial adhesion strengthening was insufficient for their intended ultra-high shear stress environment. We then hypothesized that microfabricated trenches would reduce shear stress to tolerable levels while maintaining endothelial access to the flow stream, thereby promoting a confluent and anticoagulant endothelial monolayer. Computational fluid dynamics simulations predicted an empirical relationship of channel width, depth, and spacing that would maintain interior surface shear stress within tolerable levels. Endothelial cells seeded to confluence in these channels retained a confluent monolayer when exposed to 600 dynes/cm2 shear stress for 48 hours regardless of applied adhesive ligand. Furthermore, sheared EC expressed a mature anti-coagulant profile, including endothelial nitric oxide synthase (eNOS), VE-cadherin, and significantly downregulated plasminogen activator inhibitor-1 (PAI-1). As a final test, channeled pyrolytic carbon surfaces with confluent EC reduced human platelet adhesion 1000-fold

  16. Transfer of intracellular HIV Nef to endothelium causes endothelial dysfunction.

    PubMed

    Wang, Ting; Green, Linden A; Gupta, Samir K; Kim, Chul; Wang, Liang; Almodovar, Sharilyn; Flores, Sonia C; Prudovsky, Igor A; Jolicoeur, Paul; Liu, Ziyue; Clauss, Matthias

    2014-01-01

    With effective antiretroviral therapy (ART), cardiovascular diseases (CVD) are emerging as a major cause of morbidity and death in the aging HIV-infected population. To address whether HIV-Nef, a viral protein produced in infected cells even when virus production is halted by ART, can lead to endothelial activation and dysfunction, we tested Nef protein transfer to and activity in endothelial cells. We demonstrated that Nef is essential for major endothelial cell activating effects of HIV-infected Jurkat cells when in direct contact with the endothelium. In addition, we found that Nef protein in endothelial cells is sufficient to cause apoptosis, ROS generation and release of monocyte attractant protein-1 (MCP-1). The Nef protein-dependent endothelial activating effects can be best explained by our observation that Nef protein rapidly transfers from either HIV-infected or Nef-transfected Jurkat cells to endothelial cells between these two cell types. These results are of in vivo relevance as we demonstrated that Nef protein induces GFP transfer from T cells to endothelium in CD4.Nef.GFP transgenic mice and Nef is present in chimeric SIV-infected macaques. Analyzing the signal transduction effects of Nef in endothelial cells, we found that Nef-induced apoptosis is mediated through ROS-dependent mechanisms, while MCP-1 production is NF-kB dependent. Together, these data indicate that inhibition of Nef-associated pathways may be promising new therapeutic targets for reducing the risk for cardiovascular disease in the HIV-infected population.

  17. Angiogenic microenvironment augments impaired endothelial responses under diabetic conditions.

    PubMed

    Sheikh, Abdul Q; Kuesel, Courtney; Taghian, Toloo; Hurley, Jennifer R; Huang, Wei; Wang, Yigang; Hinton, Robert B; Narmoneva, Daria A

    2014-04-15

    Diabetes-induced cardiomyopathy is characterized by cardiac remodeling, fibrosis, and endothelial dysfunction, with no treatment options currently available. Hyperglycemic memory by endothelial cells may play the key role in microvascular complications in diabetes, providing a potential target for therapeutic approaches. This study tested the hypothesis that a proangiogenic environment can augment diabetes-induced deficiencies in endothelial cell angiogenic and biomechanical responses. Endothelial responses were quantified for two models of diabetic conditions: 1) an in vitro acute and chronic hyperglycemia where normal cardiac endothelial cells were exposed to high-glucose media, and 2) an in vivo chronic diabetes model where the cells were isolated from rats with type I streptozotocin-induced diabetes. Capillary morphogenesis, VEGF and nitric oxide expression, cell morphology, orientation, proliferation, and apoptosis were determined for cells cultured on Matrigel or proangiogenic nanofiber hydrogel. The effects of biomechanical stimulation were assessed following cell exposure to uniaxial strain. The results demonstrate that diabetes alters cardiac endothelium angiogenic response, with differential effects of acute and chronic exposure to high-glucose conditions, consistent with the concept that endothelial cells may have a long-term "hyperglycemic memory" of the physiological environment in the body. Furthermore, endothelial cell exposure to strain significantly diminishes their angiogenic potential following strain application. Both diabetes and strain-associated deficiencies can be augmented in the proangiogenic nanofiber microenvironment. These findings may contribute to the development of novel approaches to reverse hyperglycemic memory of endothelium and enhance vascularization of the diabetic heart, where improved angiogenic and biomechanical responses can be the key factor to successful therapy. PMID:24573084

  18. New thiazolidinediones affect endothelial cell activation and angiogenesis.

    PubMed

    Rudnicki, Martina; Tripodi, Gustavo L; Ferrer, Renila; Boscá, Lisardo; Pitta, Marina G R; Pitta, Ivan R; Abdalla, Dulcineia S P

    2016-07-01

    Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor-γ (PPARγ) agonists used in treating type 2 diabetes that may exhibit beneficial pleiotropic effects on endothelial cells. In this study, we characterized the effects of three new TZDs [GQ-32 (3-biphenyl-4-ylmethyl-5-(4-nitro-benzylidene)-thiazolidine-2,4-dione), GQ-169 (5-(4-chloro-benzylidene)-3-(2,6-dichloro-benzyl)-thiazolidine-2,4-dione), and LYSO-7 (5-(5-bromo-1H-indol-3-ylmethylene)-3-(4-chlorobenzyl)-thiazolidine-2,4-dione)] on endothelial cells. The effects of the new TZDs were evaluated on the production of nitric oxide (NO) and reactive oxygen species (ROS), cell migration, tube formation and the gene expression of adhesion molecules and angiogenic mediators in human umbilical vein endothelial cells (HUVECs). PPARγ activation by new TZDs was addressed with a reporter gene assay. The three new TZDs activated PPARγ and suppressed the tumor necrosis factor α-induced expression of vascular cell adhesion molecule 1 and intercellular adhesion molecule 1. GQ-169 and LYSO-7 also inhibited the glucose-induced ROS production. Although NO production assessed with 4-amino-5-methylamino-2',7'-difluorofluorescein-FM probe indicated that all tested TZDs enhanced intracellular levels of NO, only LYSO-7 treatment significantly increased the release of NO from HUVEC measured by chemiluminescence analysis of culture media. Additionally, GQ-32 and GQ-169 induced endothelial cell migration and tube formation by the up-regulation of angiogenic molecules expression, such as vascular endothelial growth factor A and interleukin 8. GQ-169 also increased the mRNA levels of basic fibroblast growth factor, and GQ-32 enhanced transforming growth factor-β expression. Together, the results of this study reveal that these new TZDs act as partial agonists of PPARγ and modulate endothelial cell activation and endothelial dysfunction besides to stimulate migration and tube formation. PMID:27108791

  19. Endothelial dysfunction in inflammatory bowel diseases: Pathogenesis, assessment and implications

    PubMed Central

    Cibor, Dorota; Domagala-Rodacka, Renata; Rodacki, Tomasz; Jurczyszyn, Artur; Mach, Tomasz; Owczarek, Danuta

    2016-01-01

    Endothelial dysfunction is considered one of the etiological factors of inflammatory bowel disease (IBD). An inflammatory process leads to functional and structural changes in the vascular endothelium. An increase of leukocyte adhesiveness and leukocyte diapedesis, as well as an increased vascular smooth muscle tone and procoagulant activity is observed. Structural changes of the vascular endothelium comprise as well capillary and venule remodeling and proliferation of endothelial cells. Hypoxia in the inflammatory area stimulates angiogenesis by up-regulation of vascular endothelial growth factor, fibroblast growth factor and tumor necrosis factor-α. Inflammatory mediators also alter the lymphatic vessel function and impair lymph flow, exacerbating tissue edema and accumulation of dead cells and bacteria. The endothelial dysfunction might be diagnosed by the use of two main methods: physical and biochemical. Physical methods are based on the assessment of large arteries vasodilatation in response to an increased flow and receptors stimulation. Flow-mediated vasodilatation (FMD) is the method that is the most widely used; however, it is less sensitive in detecting early changes of the endothelium function. Most of the studies demonstrated a decrease of FMD in IBD patients but no changes in the carotic intima-media thickness. Biochemical methods of detecting the endothelial dysfunction are based on the assessment of the synthesis of compounds produced both by the normal and damaged endothelium. The endothelial dysfunction is considered an initial step in the pathogenesis of atherosclerosis in the general population. In IBD patients, the risk of cardiovascular diseases is controversial. Large, prospective studies are needed to establish the role of particular medications or dietary elements in the endothelial dysfunction as well to determine the real risk of cardiovascular diseases. PMID:26811647

  20. Targeting brain microvascular endothelial cells: a therapeutic approach to neuroprotection against stroke

    PubMed Central

    Yu, Qi-jin; Tao, Hong; Wang, Xin; Li, Ming-chang

    2015-01-01

    Brain microvascular endothelial cells form the interface between nervous tissue and circulating blood, and regulate central nervous system homeostasis. Brain microvascular endothelial cells differ from peripheral endothelial cells with regards expression of specific ion transporters and receptors, and contain fewer fenestrations and pinocytotic vesicles. Brain microvascular endothelial cells also synthesize several factors that influence blood vessel function. This review describes the morphological characteristics and functions of brain microvascular endothelial cells, and summarizes current knowledge regarding changes in brain microvascular endothelial cells during stroke progression and therapies. Future studies should focus on identifying mechanisms underlying such changes and developing possible neuroprotective therapeutic interventions. PMID:26807131

  1. Descemet's Stripping Automated Endothelial Keratoplasty versus Descemet's Membrane Endothelial Keratoplasty in the Fellow Eye for Fuchs Endothelial Dystrophy: A Retrospective Study

    PubMed Central

    Bhandari, Vipul; Reddy, Jagdeesh K.; Relekar, Kirti; Prabhu, Vijayalakshmi

    2015-01-01

    Aim. To evaluate visual outcome and endothelial cell density (ECD) after Descemet's Membrane Endothelial Keratoplasty (DMEK) in comparison with Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) in the fellow eye for Fuchs endothelial dystrophy (FED). Design. Single-centre, retrospective case series. Methods. 30 eyes of 30 patients undergoing DMEK, who completed a 1-year follow-up, were compared with 30 fellow eyes which underwent DSAEK for bilateral FED. Main outcome measures studied included Best Corrected Visual Acuity (BCVA) and ECD during a 1-year follow-up period. Results. BCVA improved from 0.78 ± 0.35 logMAR, and 0.73 ± 0.31 logMAR before surgery to 0.22 ± 0.1 logMAR and 0.35 ± 0.12 logMAR 6 months after DMEK and DSEK, respectively (P < 0.001). At one year after surgery, the BCVA was maintained at 0.21 ± 0.12 logMAR and 0.34 ± 0.1 logMAR, respectively, after DMEK and DSAEK. A statistically better visual outcome was observed after DMEK compared to DSAEK (P < 0.05) in fellow eyes. Conclusions. DMEK provided better visual rehabilitation when compared to DSAEK. Nevertheless, there were no significant differences with regard to the ECD within a 1-year follow-up. PMID:26636101

  2. Mechanisms of Tubulogenesis and Endothelial Phenotype Expression by MSCs

    PubMed Central

    Rytlewski, Julie A; Aldon, M Alejandra; Lewis, Evan W; Suggs, Laura J

    2015-01-01

    Stem cell-based therapies are a promising new avenue for treating ischemic disease and chronic wounds. Mesenchymal stem cells (MSCs) have a proven ability to augment the neovascularization processes necessary for wound healing and are widely popular as an autologous source of progenitor cells. Our lab has previously reported on PEGylated fibrin as a unique hydrogel that promotes spontaneous tubulogenesis of encapsulated MSCs without exogenous factors. However, the mechanisms underlying this process have remained unknown. To better understand the therapeutic value of PEGylated fibrin delivery of MSCs, we sought to clarify the relationship between biomaterial properties and cell behavior. Here we find that fibrin PEGylation does not dramatically alter the macroscopic mechanical properties of the fibrin-based matrix (less than 10% difference). It does, however, dramatically reduce the rate of diffusion through the gel matrix. PEGylated fibrin enhances the tubulogenic growth of encapsulated MSCs demonstrating fluid-filled lumens by interconnected MSCs. Image analysis gave a value of 4320±1770µm total network length versus 618±443µm for unmodified fibrin. PEGylation promotes the endothelial phenotype of encapsulated MSCs—compared to unmodified fibrin—as evidenced by higher levels of endothelial markers (von Willebrand factor, 2.2-fold; vascular endothelial cadherin, 1.8-fold) and vascular endothelial growth factor (VEGF, up to 1.8-fold). Prospective analysis of underlying molecular pathways demonstrated that this endothelial-like MSC behavior is sensitively modulated by hypoxic stress, but not VEGF supplementation as evidenced by a significant increase in VEGF and MMP-2 secretion per cell under hypoxia. Further gain-of-function studies under hypoxic stress demonstrated that hypoxia culture of MSCs in unmodified fibrin could increase both vWF and VE-cadherin levels to values that were not significantly different than cells cultured in PEGylated fibrin. This

  3. Synergism of matrix stiffness and vascular endothelial growth factor on mesenchymal stem cells for vascular endothelial regeneration.

    PubMed

    Wingate, Kathryn; Floren, Michael; Tan, Yan; Tseng, Pi Ou Nancy; Tan, Wei

    2014-09-01

    Mesenchymal stem cells (MSCs) hold tremendous potential for vascular tissue regeneration. Research has demonstrated that individual factors in the cell microenvironment such as matrix elasticity and growth factors regulate MSC differentiation to vascular lineage. However, it is not well understood how matrix elasticity and growth factors combine to direct the MSC fate. This study examines the combined effects of matrix elasticity and vascular endothelial growth factor (VEGF) on both MSC differentiation into endothelial lineage and MSC paracrine signaling. MSCs were seeded in soft nanofibrous matrices with or without VEGF, and in Petri dishes with or without VEGF. Only MSCs seeded in three-dimensional soft matrices with VEGF showed significant increases in the expression of endothelial markers (vWF, eNOS, Flt-1, and Flk-1), while eliminating the expression of smooth muscle marker (SM-α-actin). MSCs cultured in VEGF alone on two-dimensional dishes showed increased expression of both early-stage endothelial and smooth muscle markers, indicating immature vascular differentiation. Furthermore, MSCs cultured in soft matrices with VEGF showed faster upregulation of endothelial markers compared with MSCs cultured in VEGF alone. Paracrine signaling studies found that endothelial cells cultured in the conditioned media from MSCs differentiated in the soft matrix and VEGF condition exhibited increased migration and formation of capillary-like structures. These results demonstrate that VEGF and soft matrix elasticity act synergistically to guide MSC differentiation into mature endothelial phenotype while enhancing paracrine signaling. Therefore, it is critical to control both mechanical and biochemical factors to safely regenerate vascular tissues with MSCs.

  4. Synergism of Matrix Stiffness and Vascular Endothelial Growth Factor on Mesenchymal Stem Cells for Vascular Endothelial Regeneration

    PubMed Central

    Wingate, Kathryn; Floren, Michael; Tan, Yan; Tseng, Pi Ou Nancy

    2014-01-01

    Mesenchymal stem cells (MSCs) hold tremendous potential for vascular tissue regeneration. Research has demonstrated that individual factors in the cell microenvironment such as matrix elasticity and growth factors regulate MSC differentiation to vascular lineage. However, it is not well understood how matrix elasticity and growth factors combine to direct the MSC fate. This study examines the combined effects of matrix elasticity and vascular endothelial growth factor (VEGF) on both MSC differentiation into endothelial lineage and MSC paracrine signaling. MSCs were seeded in soft nanofibrous matrices with or without VEGF, and in Petri dishes with or without VEGF. Only MSCs seeded in three-dimensional soft matrices with VEGF showed significant increases in the expression of endothelial markers (vWF, eNOS, Flt-1, and Flk-1), while eliminating the expression of smooth muscle marker (SM-α-actin). MSCs cultured in VEGF alone on two-dimensional dishes showed increased expression of both early-stage endothelial and smooth muscle markers, indicating immature vascular differentiation. Furthermore, MSCs cultured in soft matrices with VEGF showed faster upregulation of endothelial markers compared with MSCs cultured in VEGF alone. Paracrine signaling studies found that endothelial cells cultured in the conditioned media from MSCs differentiated in the soft matrix and VEGF condition exhibited increased migration and formation of capillary-like structures. These results demonstrate that VEGF and soft matrix elasticity act synergistically to guide MSC differentiation into mature endothelial phenotype while enhancing paracrine signaling. Therefore, it is critical to control both mechanical and biochemical factors to safely regenerate vascular tissues with MSCs. PMID:24702044

  5. Collaborative Enhancement of Endothelial Targeting of Nanocarriers by Modulating Platelet-Endothelial Cell Adhesion Molecule-1/CD31 Epitope Engagement.

    PubMed

    Chacko, Ann-Marie; Han, Jingyan; Greineder, Colin F; Zern, Blaine J; Mikitsh, John L; Nayak, Madhura; Menon, Divya; Johnston, Ian H; Poncz, Mortimer; Eckmann, David M; Davies, Peter F; Muzykantov, Vladimir R

    2015-07-28

    Nanocarriers (NCs) coated with antibodies (Abs) to extracellular epitopes of the transmembrane glycoprotein PECAM (platelet endothelial cell adhesion molecule-1/CD31) enable targeted drug delivery to vascular endothelial cells. Recent studies revealed that paired Abs directed to adjacent, yet distinct epitopes of PECAM stimulate each other's binding to endothelial cells in vitro and in vivo ("collaborative enhancement"). This phenomenon improves targeting of therapeutic fusion proteins, yet its potential role in targeting multivalent NCs has not been addressed. Herein, we studied the effects of Ab-mediated collaborative enhancement on multivalent NC spheres coated with PECAM Abs (Ab/NC, ∼180 nm diameter). We found that PECAM Abs do mutually enhance endothelial cell binding of Ab/NC coated by paired, but not "self" Ab. In vitro, collaborative enhancement of endothelial binding of Ab/NC by paired Abs is modulated by Ab/NC avidity, epitope selection, and flow. Cell fixation, but not blocking of endocytosis, obliterated collaborative enhancement of Ab/NC binding, indicating that the effect is mediated by molecular reorganization of PECAM molecules in the endothelial plasmalemma. The collaborative enhancement of Ab/NC binding was affirmed in vivo. Intravascular injection of paired Abs enhanced targeting of Ab/NC to pulmonary vasculature in mice by an order of magnitude. This stimulatory effect greatly exceeded enhancement of Ab targeting by paired Abs, indicating that '"collaborative enhancement"' effect is even more pronounced for relatively large multivalent carriers versus free Abs, likely due to more profound consequences of positive alteration of epitope accessibility. This phenomenon provides a potential paradigm for optimizing the endothelial-targeted nanocarrier delivery of therapeutic agents. PMID:26153796

  6. Glioma-associated endothelial cells show evidence of replicative senescence.

    PubMed

    Charalambous, Christiana; Virrey, Jenilyn; Kardosh, Adel; Jabbour, Mark N; Qazi-Abdullah, Lubna; Pen, Ligaya; Zidovetzki, Raphael; Schönthal, Axel H; Chen, Thomas C; Hofman, Florence M

    2007-04-01

    The innately programmed process of replicative senescence has been studied extensively with respect to cancer, but primarily from the perspective of tumor cells overcoming this stringent innate barrier and acquiring the capacity for unlimited proliferation. In this study, we focus on the potential role of replicative senescence affecting the non-transformed endothelial cells of the blood vessels within the tumor microenvironment. Based on the well-documented aberrant structural and functional features of blood vessels within solid tumors, we hypothesized that tumor-derived factors may lead to premature replicative senescence in tumor-associated brain endothelial cells (TuBEC). We show here that glioma tissue, but not normal brain tissue, contains cells that express the signature of replicative senescence, senescence-associated beta-galactosidase (SA-beta-gal), on CD31-positive endothelial cells. Primary cultures of human TuBEC stain for SA-beta-gal and exhibit characteristics of replicative senescence, including increased levels of the cell cycle inhibitors p21 and p27, increased resistance to cytotoxic drugs, increased growth factor production, and inability to proliferate. These data provide the first demonstration that tumor-derived brain endothelial cells may have reached an end-stage of differentiation known as replicative senescence and underscore the need for anti-angiogenic therapies to target this unique tumor-associated endothelial cell population.

  7. Endothelial cell phagocytosis of senescent neutrophils decreases procoagulant activity.

    PubMed

    Gao, Chunyan; Xie, Rui; Li, Wen; Zhou, Jin; Liu, Shuchuan; Cao, Fenglin; Liu, Yue; Ma, Ruishuang; Si, Yu; Liu, Yan; Bi, Yayan; Gilbert, Gary E; Shi, Jialan

    2013-06-01

    Abundant senescent neutrophils traverse the vascular compartment and may contribute to pathologic conditions. For example, they become procoagulant when undergoing apoptosis and may contribute to thrombosis or inflammation. Our previous studies demonstrated a dominant clearance pathway in which the neutrophils can be phagocytosed by liver macrophages. The aim of this study was to explore an alternate pathway of neutrophil clearance by endothelial cells. Phagocytosis of the neutrophils by endothelial cells was performed using various experimental approaches includingflow cytometry, confocal microscopy and electron microscopy assays in vitro and in vivo. Procoagulant activity of cultured neutrophils was evaluated by coagulation time, factor Xase and prothrombinase assays. Lactadherin functioned as a novel probe for the detection of phosphatidylserine on apoptotic cells, an opsonin (bridge) between apoptotic cell and phagocyte for promoting phagocytosis, and an efficient anticoagulant for inhibition of factor Xase and thrombin formation. When cultured, purified human neutrophils spontaneously entered apoptosis and developed procoagulant activity that was directly related to the degree of phosphatidylserine exposure. Co-culture of aged neutrophils and endothelial cells resulted in phagocytosis of the neutrophils and prolonged coagulation time. Lactadherin diminished the procoagulant activity and increased the rate of neutrophil clearance. In vivo, neutrophils were sequestered by endothelial cells after blockade of Kupffer cells, a process that was dependent upon both phosphatidylserine exposure and P-selectin expression. Thus, the ability of endothelial cells to clear senescent neutrophils may limit the procoagulant and/or inflammatory impact of these cells.

  8. Acrylamide induces accelerated endothelial aging in a human cell model.

    PubMed

    Sellier, Cyril; Boulanger, Eric; Maladry, François; Tessier, Frédéric J; Lorenzi, Rodrigo; Nevière, Rémi; Desreumaux, Pierre; Beuscart, Jean-Baptiste; Puisieux, François; Grossin, Nicolas

    2015-09-01

    Acrylamide (AAM) has been recently discovered in food as a Maillard reaction product. AAM and glycidamide (GA), its metabolite, have been described as probably carcinogenic to humans. It is widely established that senescence and carcinogenicity are closely related. In vitro, endothelial aging is characterized by replicative senescence in which primary cells in culture lose their ability to divide. Our objective was to assess the effects of AAM and GA on human endothelial cell senescence. Human umbilical vein endothelial cells (HUVECs) cultured in vitro were used as model. HUVECs were cultured over 3 months with AAM or GA (1, 10 or 100 μM) until growth arrest. To analyze senescence, β-galactosidase activity and telomere length of HUVECs were measured by cytometry and semi-quantitative PCR, respectively. At all tested concentrations, AAM or GA reduced cell population doubling compared to the control condition (p < 0.001). β-galactosidase activity in endothelial cells was increased when exposed to AAM (≥10 μM) or GA (≥1 μM) (p < 0.05). AAM (≥10 μM) or GA (100 μM) accelerated telomere shortening in HUVECs (p < 0.05). In conclusion, in vitro chronic exposure to AAM or GA at low concentrations induces accelerated senescence. This result suggests that an exposure to AAM might contribute to endothelial aging.

  9. Inhibition of cyclooxygenase (COX)-2 affects endothelial progenitor cell proliferation

    SciTech Connect

    Colleselli, Daniela; Bijuklic, Klaudija; Mosheimer, Birgit A.; Kaehler, Christian M. . E-mail: C.M.Kaehler@uibk.ac.at

    2006-09-10

    Growing evidence indicates that inducible cyclooxygenase-2 (COX-2) is involved in the pathogenesis of inflammatory disorders and various types of cancer. Endothelial progenitor cells recruited from the bone marrow have been shown to be involved in the formation of new vessels in malignancies and discussed for being a key point in tumour progression and metastasis. However, until now, nothing is known about an interaction between COX and endothelial progenitor cells (EPC). Expression of COX-1 and COX-2 was detected by semiquantitative RT-PCR and Western blot. Proliferation kinetics, cell cycle distribution and rate of apoptosis were analysed by MTT test and FACS analysis. Further analyses revealed an implication of Akt phosphorylation and caspase-3 activation. Both COX-1 and COX-2 expression can be found in bone-marrow-derived endothelial progenitor cells in vitro. COX-2 inhibition leads to a significant reduction in proliferation of endothelial progenitor cells by an increase in apoptosis and cell cycle arrest. COX-2 inhibition leads further to an increased cleavage of caspase-3 protein and inversely to inhibition of Akt activation. Highly proliferating endothelial progenitor cells can be targeted by selective COX-2 inhibition in vitro. These results indicate that upcoming therapy strategies in cancer patients targeting COX-2 may be effective in inhibiting tumour vasculogenesis as well as angiogenic processes.

  10. SIRT6 protects against endothelial dysfunction and atherosclerosis in mice

    PubMed Central

    Xu, Suowen; Yin, Meimei; Koroleva, Marina; Mastrangelo, Michael A.; Zhang, Wenbo; Bai, Peter; Little, Peter J.; Jin, Zheng Gen

    2016-01-01

    SIRT6 is an important member of sirtuin family that represses inflammation, aging and DNA damage, three of which are causing factors for endothelial dysfunction. SIRT6 expression is decreased in atherosclerotic lesions from ApoE−/− mice and human patients. However, the role of SIRT6 in regulating vascular endothelial function and atherosclerosis is not well understood. Here we show that SIRT6 protects against endothelial dysfunction and atherosclerosis. Global and endothelium-specific SIRT6 knockout mice exhibited impaired endothelium-dependent vasorelaxation. Moreover, SIRT6+/− haploinsufficient mice fed a high-fat diet (HFD) also displayed impaired endothelium-dependent vasorelaxation. Importantly, SIRT6+/−;ApoE−/− mice after HFD feeding exhibited exacerbated atherosclerotic lesion development, concurrent with increased expression of the proinflammatory cytokine VCAM-1. Loss- and gain-of-SIRT6 function studies in cultured human endothelial cells (ECs) showed that SIRT6 attenuated monocyte adhesion to ECs. RNA-sequencing profiling revealed that SIRT6 overexpression decreased the expression of multiple atherosclerosis-related genes, including proatherogenic gene TNFSF4 (tumor necrosis factor superfamily member 4). Chromatin immunoprecipitation assays showed that SIRT6 decreased TNFSF4 gene expression by binding to and deacetylating H3K9 at TNFSF4 gene promoter. Collectively, these findings demonstrate that SIRT6 play a pivotal role in maintaining endothelial function and increased SIRT6 activity could be a new therapeutic strategy to combat atherosclerotic disease. PMID:27249230

  11. Pulmonary metastasis after bleomycin-induced endothelial injury and repair

    SciTech Connect

    Adamson, I.Y.R.; Young, L.; Orr, F.W.

    1986-03-01

    Injury to the endothelial barrier is thought to enhance the localization and metastasis of circulating tumor cells. This hypothesis was tested by inducing pulmonary endothelial injury in C57bl/6 mice by injecting a single IV dose of bleomycine (120 mg/kg). After 5 days, severe endothelial injury was demonstrated by morphology and by increased levels of protein in lung lavage fluid. When /sup 131/I-iododeoxyuridine labeled syngeneic fibrosarcoma cells were injected IV at this time, a 9 fold increase in their localization was detected 24 hrs later in bleomycin-treated lungs compared to saline controls. By EM, tumor cells were observed at sites of denuded vascular basement membrane. There was also a significant increase in subsequent gross metastases and percentage of lung occupied by tumor in the bleomycin group. Animals examined 10 days after bleomycin showed less endothelial damage and a smaller increase in tumor cell localization and metastases. At 21 days, when endothelial structure and alveolar protein levels had returned to normal, and at 6 weeks, when there was focal fibrosis, no increase in tumor cell localization or metastases was found. It is concluded that damage to the pulmonary endothelium is a key factor in enhancing the trapping of circulating tumor cells and increasing metastatic tumor growth.

  12. Glioma-associated endothelial cells show evidence of replicative senescence

    SciTech Connect

    Charalambous, Christiana; Virrey, Jenilyn; Kardosh, Adel; Jabbour, Mark N.; Qazi-Abdullah, Lubna; Pen, Ligaya; Zidovetzki, Raphael; Schoenthal, Axel H.; Chen, Thomas C.; Hofman, Florence M. . E-mail: hofman@usc.edu

    2007-04-01

    The innately programmed process of replicative senescence has been studied extensively with respect to cancer, but primarily from the perspective of tumor cells overcoming this stringent innate barrier and acquiring the capacity for unlimited proliferation. In this study, we focus on the potential role of replicative senescence affecting the non-transformed endothelial cells of the blood vessels within the tumor microenvironment. Based on the well-documented aberrant structural and functional features of blood vessels within solid tumors, we hypothesized that tumor-derived factors may lead to premature replicative senescence in tumor-associated brain endothelial cells (TuBEC). We show here that glioma tissue, but not normal brain tissue, contains cells that express the signature of replicative senescence, senescence-associated {beta}-galactosidase (SA-{beta}-gal), on CD31-positive endothelial cells. Primary cultures of human TuBEC stain for SA-{beta}-gal and exhibit characteristics of replicative senescence, including increased levels of the cell cycle inhibitors p21 and p27, increased resistance to cytotoxic drugs, increased growth factor production, and inability to proliferate. These data provide the first demonstration that tumor-derived brain endothelial cells may have reached an end-stage of differentiation known as replicative senescence and underscore the need for anti-angiogenic therapies to target this unique tumor-associated endothelial cell population.

  13. Endothelial biocompatibility and accumulation of SPION under flow conditions

    NASA Astrophysics Data System (ADS)

    Matuszak, Jasmin; Zaloga, Jan; Friedrich, Ralf P.; Lyer, Stefan; Nowak, Johannes; Odenbach, Stefan; Alexiou, Christoph; Cicha, Iwona

    2015-04-01

    Magnetic targeting is considered a promising method to accumulate the nanoparticles at the sites of atherosclerotic lesions, but little is known about the biological effects of magnetic nanoparticles on the vascular wall. Here, we investigated endothelial cell growth and vitality upon treatment with SPION (0-60 μg/mL) using two complementing methods: real-time cell analysis and live-cell microscopy. Moreover, the uptake of circulating superparamagnetic iron oxide nanoparticles (SPIONs) was assessed in an in vitro model of arterial bifurcations. At the tested concentrations, SPIONs were well tolerated and had no major influence on endothelial cell growth. Our results further showed a uniform distribution of endothelial SPION uptake independent of channel geometry or hemodynamic conditions: In the absence of magnetic force, no increase in accumulation of SPIONs at non-uniform shear stress region at the outer walls of bifurcation was observed. Application of external magnet allowed enhanced accumulation of SPIONs at the regions of non-uniform shear stress. Increased uptake of SPIONs at non-uniform shear stress region was well tolerated by endothelial cells (ECs) and did not affect endothelial cell viability or attachment. These findings indicate that magnetic targeting can constitute a promising and safe technique for the delivery of imaging and therapeutic nanoparticles to atherosclerotic lesions.

  14. Effects of shear stress on endothelial progenitor cells.

    PubMed

    Obi, Syotaro; Yamamoto, Kimiko; Ando, Joji

    2014-10-01

    Endothelial progenitor cells (EPCs) are adult stem cells that play a central role in neovascularization. EPCs are mobilized from bone marrow into peripheral blood, attach to existing endothelial cells, and then transmigrate across the endothelium into tissues, where they proliferate, differentiate, and form new blood vessels. In the process, EPCs are exposed to shear stress, a biomechanical force generated by flowing blood and tissue fluid flow. When cultured EPCs are exposed to controlled levels of shear stress in a flow-loading device, their bioactivities in terms of proliferation, anti-apoptosis, migration, production of bioactive substances, anti-thrombosis, and tube formation increase markedly. Expression of endothelial marker genes and proteins by EPCs also increases in response to shear stress, and they differentiate into mature endothelial cells. Great advances have been made in elucidating the mechanisms by which mature endothelial cells sense and respond to shear stress, but not in EPCs. Further study of EPC responses to shear stress will be necessary to better understand the physiological and pathophysiological roles of EPCs and to apply EPCs to new therapies in the field of regenerative medicine. PMID:25992410

  15. Immunolocalization of endocan during the endothelial-mesenchymal transition process

    PubMed Central

    Carrillo, L.M.; Arciniegas, E.; Rojas, H.; Ramírez, R.

    2011-01-01

    Endocan is a dermatan sulfate proteoglycan (DSPG) that has been observed in the cytoplasm of endothelial cells of small and large vessels in lung, kidney, liver, colon, ovary and brain tumors. This DSPG has been implicated in the regulation of cellular activities such as adhesion, migration, and proliferation. Given the important roles played by endocan in such processes, we sought to determine whether this DSPG is present in the chicken embryo aortic wall in embryonic days 12 and 14, when intimal thickening and endothelial transformation are notorious. Immunolabeling of serial paraffin cross-sections revealed endocan immunoreactivity at the endothelium and some mesenchymal cells constituting the intimal thickening but not in the cells arranged in lamellar layers. We also investigated whether endocan was present in monolayers of primary embryonic aortic endothelial cells attached to fibronectin when they were deprived of serum and stimulated with epidermal growth factor. Immunofluorescence determined that in the epidermal growth factor (EGF) condition where separating, detaching, and migrating cells were observed, endocan appeared organized in arrays typical of focal complexes in the leading edge of these cells. In serum-free medium condition in which the endothelial cells displayed a cobblestone appearance, endocan appeared mainly delineating the margin of many cells. This study demonstrates for the first time the presence of endocan during the aortic wall remodeling, and provides evidence that suggests a possible contribution of this DSPG in the endothelial-mesenchymal transition (EndoMT) process. PMID:22201190

  16. Reversibility of endothelial dysfunction in diabetes: role of polyphenols.

    PubMed

    Suganya, N; Bhakkiyalakshmi, E; Sarada, D V L; Ramkumar, K M

    2016-07-01

    The endothelium, a thin single sheet of endothelial cells, is a metabolically active layer that coats the inner surface of blood vessels and acts as an interface between the circulating blood and the vessel wall. The endothelium through the secretion of vasodilators and vasoconstrictors serves as a critical mediator of vascular homeostasis. During the development of the vascular system, it regulates cellular adhesion and vessel wall inflammation in addition to maintaining vasculogenesis and angiogenesis. A shift in the functions of the endothelium towards vasoconstriction, proinflammatory and prothrombic states characterise improper functioning of these cells, leading to endothelial dysfunction (ED), implicated in the pathogenesis of many diseases including diabetes. Major mechanisms of ED include the down-regulation of endothelial nitric oxide synthase levels, differential expression of vascular endothelial growth factor, endoplasmic reticulum stress, inflammatory pathways and oxidative stress. ED tends to be the initial event in macrovascular complications such as coronary artery disease, peripheral arterial disease, stroke and microvascular complications such as nephropathy, neuropathy and retinopathy. Numerous strategies have been developed to protect endothelial cells against various stimuli, of which the role of polyphenolic compounds in modulating the differentially regulated pathways and thus maintaining vascular homeostasis has been proven to be beneficial. This review addresses the factors stimulating ED in diabetes and the molecular mechanisms of natural polyphenol antioxidants in maintaining vascular homeostasis. PMID:27264638

  17. Simvastatin Ameliorates Matrix Stiffness-Mediated Endothelial Monolayer Disruption.

    PubMed

    Lampi, Marsha C; Faber, Courtney J; Huynh, John; Bordeleau, Francois; Zanotelli, Matthew R; Reinhart-King, Cynthia A

    2016-01-01

    Arterial stiffening accompanies both aging and atherosclerosis, and age-related stiffening of the arterial intima increases RhoA activity and cell contractility contributing to increased endothelium permeability. Notably, statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors whose pleiotropic effects include disrupting small GTPase activity; therefore, we hypothesized the statin simvastatin could be used to attenuate RhoA activity and inhibit the deleterious effects of increased age-related matrix stiffness on endothelial barrier function. Using polyacrylamide gels with stiffnesses of 2.5, 5, and 10 kPa to mimic the physiological stiffness of young and aged arteries, endothelial cells were grown to confluence and treated with simvastatin. Our data indicate that RhoA and phosphorylated myosin light chain activity increase with matrix stiffness but are attenuated when treated with the statin. Increases in cell contractility, cell-cell junction size, and indirect measurements of intercellular tension that increase with matrix stiffness, and are correlated with matrix stiffness-dependent increases in monolayer permeability, also decrease with statin treatment. Furthermore, we report that simvastatin increases activated Rac1 levels that contribute to endothelial barrier enhancing cytoskeletal reorganization. Simvastatin, which is prescribed clinically due to its ability to lower cholesterol, alters the endothelial cell response to increased matrix stiffness to restore endothelial monolayer barrier function, and therefore, presents a possible therapeutic intervention to prevent atherogenesis initiated by age-related arterial stiffening.

  18. Simvastatin Ameliorates Matrix Stiffness-Mediated Endothelial Monolayer Disruption

    PubMed Central

    Lampi, Marsha C.; Faber, Courtney J.; Huynh, John; Bordeleau, Francois; Zanotelli, Matthew R.; Reinhart-King, Cynthia A.

    2016-01-01

    Arterial stiffening accompanies both aging and atherosclerosis, and age-related stiffening of the arterial intima increases RhoA activity and cell contractility contributing to increased endothelium permeability. Notably, statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors whose pleiotropic effects include disrupting small GTPase activity; therefore, we hypothesized the statin simvastatin could be used to attenuate RhoA activity and inhibit the deleterious effects of increased age-related matrix stiffness on endothelial barrier function. Using polyacrylamide gels with stiffnesses of 2.5, 5, and 10 kPa to mimic the physiological stiffness of young and aged arteries, endothelial cells were grown to confluence and treated with simvastatin. Our data indicate that RhoA and phosphorylated myosin light chain activity increase with matrix stiffness but are attenuated when treated with the statin. Increases in cell contractility, cell-cell junction size, and indirect measurements of intercellular tension that increase with matrix stiffness, and are correlated with matrix stiffness-dependent increases in monolayer permeability, also decrease with statin treatment. Furthermore, we report that simvastatin increases activated Rac1 levels that contribute to endothelial barrier enhancing cytoskeletal reorganization. Simvastatin, which is prescribed clinically due to its ability to lower cholesterol, alters the endothelial cell response to increased matrix stiffness to restore endothelial monolayer barrier function, and therefore, presents a possible therapeutic intervention to prevent atherogenesis initiated by age-related arterial stiffening. PMID:26761203

  19. Endothelial Notch activity promotes angiogenesis and osteogenesis in bone

    NASA Astrophysics Data System (ADS)

    Ramasamy, Saravana K.; Kusumbe, Anjali P.; Wang, Lin; Adams, Ralf H.

    2014-03-01

    Blood vessel growth in the skeletal system and osteogenesis seem to be coupled, suggesting the existence of molecular crosstalk between endothelial and osteoblastic cells. Understanding the nature of the mechanisms linking angiogenesis and bone formation should be of great relevance for improved fracture healing or prevention of bone mass loss. Here we show that vascular growth in bone involves a specialized, tissue-specific form of angiogenesis. Notch signalling promotes endothelial cell proliferation and vessel growth in postnatal long bone, which is the opposite of the well-established function of Notch and its ligand Dll4 in the endothelium of other organs and tumours. Endothelial-cell-specific and inducible genetic disruption of Notch signalling in mice not only impaired bone vessel morphology and growth, but also led to reduced osteogenesis, shortening of long bones, chondrocyte defects, loss of trabeculae and decreased bone mass. On the basis of a series of genetic experiments, we conclude that skeletal defects in these mutants involved defective angiocrine release of Noggin from endothelial cells, which is positively regulated by Notch. Administration of recombinant Noggin, a secreted antagonist of bone morphogenetic proteins, restored bone growth and mineralization, chondrocyte maturation, the formation of trabeculae and osteoprogenitor numbers in endothelial-cell-specific Notch pathway mutants. These findings establish a molecular framework coupling angiogenesis, angiocrine signals and osteogenesis, which may prove significant for the development of future therapeutic applications.

  20. Endothelial Notch activity promotes angiogenesis and osteogenesis in bone.

    PubMed

    Ramasamy, Saravana K; Kusumbe, Anjali P; Wang, Lin; Adams, Ralf H

    2014-03-20

    Blood vessel growth in the skeletal system and osteogenesis seem to be coupled, suggesting the existence of molecular crosstalk between endothelial and osteoblastic cells. Understanding the nature of the mechanisms linking angiogenesis and bone formation should be of great relevance for improved fracture healing or prevention of bone mass loss. Here we show that vascular growth in bone involves a specialized, tissue-specific form of angiogenesis. Notch signalling promotes endothelial cell proliferation and vessel growth in postnatal long bone, which is the opposite of the well-established function of Notch and its ligand Dll4 in the endothelium of other organs and tumours. Endothelial-cell-specific and inducible genetic disruption of Notch signalling in mice not only impaired bone vessel morphology and growth, but also led to reduced osteogenesis, shortening of long bones, chondrocyte defects, loss of trabeculae and decreased bone mass. On the basis of a series of genetic experiments, we conclude that skeletal defects in these mutants involved defective angiocrine release of Noggin from endothelial cells, which is positively regulated by Notch. Administration of recombinant Noggin, a secreted antagonist of bone morphogenetic proteins, restored bone growth and mineralization, chondrocyte maturation, the formation of trabeculae and osteoprogenitor numbers in endothelial-cell-specific Notch pathway mutants. These findings establish a molecular framework coupling angiogenesis, angiocrine signals and osteogenesis, which may prove significant for the development of future therapeutic applications.

  1. Endothelial cells regulate neural crest and second heart field morphogenesis

    PubMed Central

    Milgrom-Hoffman, Michal; Michailovici, Inbal; Ferrara, Napoleone; Zelzer, Elazar; Tzahor, Eldad

    2014-01-01

    ABSTRACT Cardiac and craniofacial developmental programs are intricately linked during early embryogenesis, which is also reflected by a high frequency of birth defects affecting both regions. The molecular nature of the crosstalk between mesoderm and neural crest progenitors and the involvement of endothelial cells within the cardio–craniofacial field are largely unclear. Here we show in the mouse that genetic ablation of vascular endothelial growth factor receptor 2 (Flk1) in the mesoderm results in early embryonic lethality, severe deformation of the cardio–craniofacial field, lack of endothelial cells and a poorly formed vascular system. We provide evidence that endothelial cells are required for migration and survival of cranial neural crest cells and consequently for the deployment of second heart field progenitors into the cardiac outflow tract. Insights into the molecular mechanisms reveal marked reduction in Transforming growth factor beta 1 (Tgfb1) along with changes in the extracellular matrix (ECM) composition. Our collective findings in both mouse and avian models suggest that endothelial cells coordinate cardio–craniofacial morphogenesis, in part via a conserved signaling circuit regulating ECM remodeling by Tgfb1. PMID:24996922

  2. Directed endothelial cell morphogenesis in micropatterned gelatin methacrylate hydrogels.

    PubMed

    Nikkhah, Mehdi; Eshak, Nouran; Zorlutuna, Pinar; Annabi, Nasim; Castello, Marco; Kim, Keekyoung; Dolatshahi-Pirouz, Alireza; Edalat, Faramarz; Bae, Hojae; Yang, Yunzhi; Khademhosseini, Ali

    2012-12-01

    Engineering of organized vasculature is a crucial step in the development of functional and clinically relevant tissue constructs. A number of previous techniques have been proposed to spatially regulate the distribution of angiogenic biomolecules and vascular cells within biomaterial matrices to promote vascularization. Most of these approaches have been limited to two-dimensional (2D) micropatterned features or have resulted in formation of random vasculature within three-dimensional (3D) microenvironments. In this study, we investigate 3D endothelial cord formation within micropatterned gelatin methacrylate (GelMA) hydrogels with varying geometrical features (50-150 μm height). We demonstrated the significant dependence of endothelial cells proliferation, alignment and cord formation on geometrical dimensions of the patterned features. The cells were able to align and organize within the micropatterned constructs and assemble to form cord structures with organized actin fibers and circular/elliptical cross-sections. The inner layer of the cord structure was filled with gel showing that the micropatterned hydrogel constructs guided the assembly of endothelial cells into cord structures. Notably, the endothelial cords were retained within the hydrogel microconstructs for all geometries after two weeks of culture; however, only the 100 μm-high constructs provided the optimal microenvironment for the formation of circular and stable cord structures. Our findings suggest that endothelial cord formation is a preceding step to tubulogenesis and the proposed system can be used to develop organized vasculature for engineered tissue constructs.

  3. Directed Endothelial Cell Morphogenesis in Micropatterned Gelatin Methacrylate Hydrogels

    PubMed Central

    Nikkhah, Mehdi; Eshak, Nouran; Zorlutuna, Pinar; Annabi, Nasim; Castello, Marco; Kim, Keekyoung; Dolatshahi-Pirouz, Alireza; Edalat, Faramarz; Bae, Hojae; Yang, Yunzhi; Khademhosseini, Ali

    2013-01-01

    Engineering of organized vasculature is a crucial step in the development of functional and clinically relevant tissue constructs. A number of previous techniques have been proposed to spatially regulate the distribution of angiogenic biomolecules and vascular cells within biomaterial matrices to promote vascularization. Most of these approaches have been limited to two-dimensional (2D) micropatterned features or have resulted in formation of random vasculature within three-dimensional (3D) microenvironments. In this study, we investigate 3D endothelial cord formation within micropatterned gelatin methacrylate (GelMA) hydrogels with varying geometrical features (50–150 µm height). We demonstrated the significance dependence of endothelial cells proliferation, alignment and cord formation on geometrical dimensions of the patterned features. The cells were able to align and organize within the micropatterned constructs and assemble to form cord structures with organized actin fibers and circular/elliptical cross-sections. The inner layer of the cord structure was filled with gel showing that the micropatterned hydrogel constructs guided the assembly of endothelial cells into cord structures. Notably, the endothelial cords were retained within the hydrogel microconstructs for all geometries after two weeks of culture; however, only the 100 µm-high constructs provided the optimal microenvironment for the formation of circular and stable cord structures. Our findings suggest that endothelial cord formation is a preceding step to tubulogenesis and the proposed system can be used to develop organized vasculature for engineered tissue constructs. PMID:23018132

  4. Role of Endothelial Cells in Myocardial Ischemia-Reperfusion Injury

    PubMed Central

    Singhal, Arun K.; Symons, J. David; Boudina, Sihem; Jaishy, Bharat; Shiu, Yan-Ting

    2014-01-01

    Minimizing myocardial ischemia-reperfusion injury has broad clinical implications and is a critical mediator of cardiac surgical outcomes. “Ischemic injury” results from a restriction in blood supply leading to a mismatch between oxygen supply and demand of a sufficient intensity and/or duration that leads to cell necrosis, whereas ischemia-reperfusion injury occurs when blood supply is restored after a period of ischemia and is usually associated with apoptosis (i.e. programmed cell death). Compared to vascular endothelial cells, cardiac myocytes are more sensitive to ischemic injury and have received the most attention in preventing myocardial ischemia-reperfusion injury. Many comprehensive reviews exist on various aspects of myocardial ischemia-reperfusion injury. The purpose of this review is to examine the role of vascular endothelial cells in myocardial ischemia-reperfusion injury, and to stimulate further research in this exciting and clinically relevant area. Two specific areas that are addressed include: 1) data suggesting that coronary endothelial cells are critical mediators of myocardial dysfunction after ischemia-reperfusion injury; and 2) the involvement of the mitochondrial permeability transition pore in endothelial cell death as a result of an ischemia-reperfusion insult. Elucidating the cellular signaling pathway(s) that leads to endothelial cell injury and/or death in response to ischemia-reperfusion is a key component to developing clinically applicable strategies that might minimize myocardial ischemia-reperfusion injury. PMID:25558187

  5. The Endothelial Glycocalyx: New Diagnostic and Therapeutic Approaches in Sepsis

    PubMed Central

    Koczera, Patrick

    2016-01-01

    Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. The endothelial glycocalyx is one of the earliest sites involved during sepsis. This fragile layer is a complex network of cell-bound proteoglycans, glycosaminoglycan side chains, and sialoproteins lining the luminal side of endothelial cells with a thickness of about 1 to 3 μm. Sepsis-associated alterations of its structure affect endothelial permeability and result in the liberation of endogenous damage-associated molecular patterns (DAMPs). Once liberated in the circulatory system, DAMPs trigger the devastating consequences of the proinflammatory cascades in sepsis and septic shock. In this way, the injury to the glycocalyx with the consecutive release of DAMPs contributes to a number of specific clinical effects of sepsis, including acute kidney injury, respiratory failure, and septic cardiomyopathy. Moreover, the extent of glycocalyx degradation serves as a marker of endothelial dysfunction and sepsis severity. In this review, we highlight the crucial role of the glycocalyx in sepsis as a diagnostic tool and discuss the potential of members of the endothelial glycocalyx serving as hopeful therapeutic targets in sepsis-associated multiple organ failures. PMID:27699168

  6. Traction Forces of Endothelial Cells under Slow Shear Flow

    PubMed Central

    Perrault, Cecile M.; Brugues, Agusti; Bazellieres, Elsa; Ricco, Pierre; Lacroix, Damien; Trepat, Xavier

    2015-01-01

    Endothelial cells are constantly exposed to fluid shear stresses that regulate vascular morphogenesis, homeostasis, and disease. The mechanical responses of endothelial cells to relatively high shear flow such as that characteristic of arterial circulation has been extensively studied. Much less is known about the responses of endothelial cells to slow shear flow such as that characteristic of venous circulation, early angiogenesis, atherosclerosis, intracranial aneurysm, or interstitial flow. Here we used a novel, to our knowledge, microfluidic technique to measure traction forces exerted by confluent vascular endothelial cell monolayers under slow shear flow. We found that cells respond to flow with rapid and pronounced increases in traction forces and cell-cell stresses. These responses are reversible in time and do not involve reorientation of the cell body. Traction maps reveal that local cell responses to slow shear flow are highly heterogeneous in magnitude and sign. Our findings unveil a low-flow regime in which endothelial cell mechanics is acutely responsive to shear stress. PMID:26488643

  7. Endothelial Dysfunction and Amyloid-β-Induced Neurovascular Alterations.

    PubMed

    Koizumi, Kenzo; Wang, Gang; Park, Laibaik

    2016-03-01

    Alzheimer's disease (AD) and cerebrovascular diseases share common vascular risk factors that have disastrous effects on cerebrovascular regulation. Endothelial cells, lining inner walls of cerebral blood vessels, form a dynamic interface between the blood and the brain and are critical for the maintenance of neurovascular homeostasis. Accordingly, injury in endothelial cells is regarded as one of the earliest symptoms of impaired vasoregulatory mechanisms. Extracellular buildup of amyloid-β (Aβ) is a central pathogenic factor in AD. Aβ exerts potent detrimental effects on cerebral blood vessels and impairs endothelial structure and function. Recent evidence implicates vascular oxidative stress and activation of the non-selective cationic channel transient receptor potential melastatin (TRPM)-2 on endothelial cells in the mechanisms of Aβ-induced neurovascular dysfunction. Thus, Aβ triggers opening of TRPM2 channels in endothelial cells leading to intracellular Ca(2+) overload and vasomotor dysfunction. The cerebrovascular dysfunction may contribute to AD pathogenesis by reducing the cerebral blood supply, leading to increased susceptibility to vascular insufficiency, and by promoting Aβ accumulation. The recent realization that vascular factors contribute to AD pathobiology suggests new targets for the prevention and treatment of this devastating disease. PMID:26328781

  8. Endothelial dysfunction and tendinopathy: how far have we come?

    PubMed

    Papalia, R; Moro, L; Franceschi, F; Albo, E; D'Adamio, S; Di Martino, A; Vadalà, G; Faldini, C; Denaro, V

    2013-12-01

    Symptomatic tendon tears are one of the most important causes of pain and joint dysfunction. Among the intrinsic causes, vascularization recently gained a major role. Endothelial function is indeed a key factor, as well as vascular tone and thrombotic factors, in the regulation of vascular homeostasis and the composition of vascular wall. In this review, we studied systematically whether there is a relationship between endothelial dysfunction and tendinopathy. A literature search was performed using the isolated or combined keywords endothelial dysfunction and tendon,' 'nitric oxide (NO) and tendinopathy,' and 'endothelial dysfunction in tendon healing.' We identified 21 published studies. Of the selected studies, 9 were in vivo studies, 2 focusing on animals and 7 on humans, while 12 reported about in vitro evaluations, where 7 were carried out on humans and 5 on animals. The evidence about a direct relationship between tendinopathy and endothelial dysfunction is still poor. As recent studies have shown, there is no significant improvement in clinical and functional assessments after treatment with NO in patients suffering from tendinopathy in different locations. No significant differences were identified in the outcomes reported for experiment group when compared with controls treated with conventional surgical procedures or rehabilitation programs. Nitric oxide could be a marker to quantify the response of the endothelium to mechanical stress or hypoxia indicating the final balance between vasodilatating and vasoconstricting factors and their effects, but more ad stronger evidence is still needed to fully support this practice. PMID:23907599

  9. The role of hydrogen peroxide in endothelial proliferative responses.

    PubMed

    Stone, James R; Collins, Tucker

    2002-01-01

    Hydrogen peroxide (H2O2) is a recently recognized second messenger regulating proliferation in mammalian cells. Endothelial cells possess NADPH oxidases, which produce the H202 precursor superoxide (.O2-) in response to receptor-mediated signaling. Multiple physiologic agents have been shown to stimulate endothelial cells to produce .O2-/H2O2, including growth factors, such as vascular endothelial growth factor and transforming growth factor-beta1, and alterations in biomechanical forces, such as shear stress and cyclic strain. Downstream effects of these stimuli can often be inhibited by scavenging H2O2. Low concentrations of H2O2 stimulate proliferation or enhanced survival in a wide variety of cell types. Also, low concentrations of H2O2 stimulate endothelial migration as well as tube formation in an in vitro model of angiogenesis. Although low concentrations of H2O2 have been shown to be involved in numerous signal transduction pathways and to independently stimulate mitogenesis, there has been little information presented on precisely how mammalian cells respond biochemically to these low concentrations of H2O2. Recently a functional proteomics approach has been utilized to identify proteins responsive to low concentrations of H2O2 in human endothelial cells.

  10. Filamin redistribution in an endothelial cell reoxygenation injury model.

    PubMed

    Hastie, L E; Patton, W F; Hechtman, H B; Shepro, D

    1997-01-01

    Ischemia-reperfusion injury increases vascular permeability in part by generating reactive oxygen species that disassemble the endothelial cell actin dense peripheral band. This is followed by an increase in the number and diameter of intercellular gaps. Millimolar concentrations of reactive oxygen metabolites lead to nonspecific endothelial cell injury, but micromolar concentrations activate inflammatory second messenger cascades which produce distributional changes in endothelial cell cytoskeletal proteins. H2O2 (100 microM) causes translocation of filamin, from the membrane to the cytosol within 1 min. Subsequently, gap formation occurs within 10-25 min, which is attributed to rearrangement of the dense peripheral band of F-actin. Plasma membrane blebbing occurs after 90 min and decreases in mitochondrial activity occur after 1-2 h. Deferoxamine (iron chelator) and TEMPO (nonspecific free radical scavenger) inhibit these changes. H2O2 (100-1000 microM) does not increase endothelial cell intracellular Ca2+ through 30 min and pretreating cells with a Ca2+-calmodulin kinase inhibitor or an intracellular Ca2+ chelator does not prevent filamin translocation. Filamin redistribution and actin rearrangement are early events in H2O2-mediated endothelial cell injury that appear to occur through Ca2+-independent pathways.

  11. Tumor necrosis factor alpha-induced pulmonary vascular endothelial injury.

    PubMed Central

    Goldblum, S E; Hennig, B; Jay, M; Yoneda, K; McClain, C J

    1989-01-01

    Tumor necrosis factor alpha (TNF-alpha) mediates components of the acute-phase response, stimulates granulocyte metabolism, and induces endothelial cell surface changes. We studied whether human recombinant TNF-alpha (rTNF-alpha) could increase pulmonary edema formation and pulmonary vascular permeability. Rabbits preinfused with 125I-albumin were administered rTNF-alpha or saline. Animals were sacrificed, and lung wet/dry weight ratios as well as bronchoalveolar lavage fluid and plasma 125I activities were determined. rTNF-alpha increased lung wet/dry weight ratios by 151% (P less than 0.02) and bronchoalveolar lavage fluid/plasma 125I activity ratios by 376% (P less than 0.01) compared with values for saline controls. Electron microscopy of lung sections demonstrated endothelial injury, perivascular edema, and extravasation of an ultrastructural permeability tracer. To demonstrate that rTNF-alpha could directly increase pulmonary vascular endothelial permeability in vitro, we studied albumin transfer across cultured porcine pulmonary artery endothelial cell monolayers. rTNF-alpha induced time-dependent dose-response increments in transendothelial albumin flux in the absence of granulocyte effector cells. These observations suggest that rTNF-alpha can provoke acute pulmonary vascular endothelial injury in vivo as well as in vitro. Images PMID:2925247

  12. The Endothelial Glycocalyx: New Diagnostic and Therapeutic Approaches in Sepsis

    PubMed Central

    Koczera, Patrick

    2016-01-01

    Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. The endothelial glycocalyx is one of the earliest sites involved during sepsis. This fragile layer is a complex network of cell-bound proteoglycans, glycosaminoglycan side chains, and sialoproteins lining the luminal side of endothelial cells with a thickness of about 1 to 3 μm. Sepsis-associated alterations of its structure affect endothelial permeability and result in the liberation of endogenous damage-associated molecular patterns (DAMPs). Once liberated in the circulatory system, DAMPs trigger the devastating consequences of the proinflammatory cascades in sepsis and septic shock. In this way, the injury to the glycocalyx with the consecutive release of DAMPs contributes to a number of specific clinical effects of sepsis, including acute kidney injury, respiratory failure, and septic cardiomyopathy. Moreover, the extent of glycocalyx degradation serves as a marker of endothelial dysfunction and sepsis severity. In this review, we highlight the crucial role of the glycocalyx in sepsis as a diagnostic tool and discuss the potential of members of the endothelial glycocalyx serving as hopeful therapeutic targets in sepsis-associated multiple organ failures.

  13. Tubedown regulation of retinal endothelial permeability signaling pathways

    PubMed Central

    Ho, Nhu; Gendron, Robert L.; Grozinger, Kindra; Whelan, Maria A.; Hicks, Emily Anne; Tennakoon, Bimal; Gardiner, Danielle; Good, William V.; Paradis, Hélène

    2015-01-01

    ABSTRACT Tubedown (Tbdn; Naa15), a subunit of the N-terminal acetyltransferase NatA, complexes with the c-Src substrate Cortactin and supports adult retinal homeostasis through regulation of vascular permeability. Here we investigate the role of Tbdn expression on signaling components of retinal endothelial permeability to understand how Tbdn regulates the vasculature and supports retinal homeostasis. Tbdn knockdown-induced hyperpermeability to Albumin in retinal endothelial cells was associated with an increase in the levels of activation of the Src family kinases (SFK) c-Src, Fyn and Lyn and phospho-Cortactin (Tyr421). The knockdown of Cortactin expression reduced Tbdn knockdown-induced permeability to Albumin and the levels of activated SFK. Inhibition of SFK in retinal endothelial cells decreased Tbdn knockdown-induced permeability to Albumin and phospho-Cortactin (Tyr421) levels. Retinal lesions of endothelial-specific Tbdn knockdown mice, with tissue thickening, fibrovascular growth, and hyperpermeable vessels displayed an increase in the levels of activated c-Src. Moreover, the retinal lesions of patients with proliferative diabetic retinopathy (PDR) associated with a loss of Tbdn expression and hyperpermeability to Albumin displayed increased levels of activated SFK in retinal blood vessels. Taken together, these results implicate Tbdn as an important regulator of retinal endothelial permeability and homeostasis by modulating a signaling pathway involving c-Src and Cortactin. PMID:26142315

  14. Fibroblast nemosis induces angiogenic responses of endothelial cells

    SciTech Connect

    Enzerink, Anna; Rantanen, Ville; Vaheri, Antti

    2010-03-10

    Increasing evidence points to a central link between inflammation and activation of the stroma, especially of fibroblasts therein. However, the mechanisms leading to such activation mostly remain undescribed. We have previously characterized a novel type of fibroblast activation (nemosis) where clustered fibroblasts upregulated the production of cyclooxygenase-2, secretion of prostaglandins, proteinases, chemotactic cytokines, and hepatocyte growth factor (HGF), and displayed activated nuclear factor-{kappa}B. Now we show that nemosis drives angiogenic responses of endothelial cells. In addition to HGF, nemotic fibroblasts secreted vascular endothelial growth factor (VEGF), and conditioned medium from spheroids promoted sprouting and networking of human umbilical venous endothelial cells (HUVEC). The response was partly inhibited by function-blocking antibodies against HGF and VEGF. Conditioned nemotic fibroblast medium promoted closure of HUVEC and human dermal microvascular endothelial cell monolayer wounds, by increasing the motility of the endothelial cells. Wound closure in HUVEC cells was partly inhibited by the antibodies against HGF. The stromal microenvironment regulates wound healing responses and often promotes tumorigenesis. Nemosis offers clues to the activation process of stromal fibroblasts and provides a model to study the part they play in angiogenesis-related conditions, as well as possibilities for therapeutical approaches desiring angiogenesis in tissue.

  15. Endostatin induces acute endothelial nitric oxide and prostacyclin release

    SciTech Connect

    Li Chunying; Harris, M. Brennan; Venema, Virginia J.; Venema, Richard C. . E-mail: rvenema@mcg.edu

    2005-04-15

    Chronic exposure to endostatin (ES) blocks endothelial cell (EC) proliferation, and migration and induces EC apoptosis thereby inhibiting angiogenesis. Nitric oxide (NO) and prostacyclin (PGI{sub 2}), in contrast, play important roles in promoting angiogenesis. In this study, we examined the acute effects of ES on endothelial NO and PGI{sub 2} production. Unexpectedly, a cGMP reporter cell assay showed that ES-induced acute endothelial NO release in cultured bovine aortic endothelial cells (BAECs). Enzyme immunoassay showed that ES also induced an acute increase in PGI{sub 2} production in BAECs. These results were confirmed by ex vivo vascular ring studies that showed vascular relaxation in response to ES. Immunoblot analysis showed that ES stimulated acute phosphorylation of endothelial nitric oxide synthase (eNOS) at Ser116, Ser617, Ser635, and Ser1179, and dephosphorylation at Thr497 in BAECs, events associated with eNOS activation. Short-term exposure of EC to ES, therefore, unlike long-term exposure which is anti-angiogenic, may be pro-angiogenic.

  16. The effects of glucocorticoids on cultured human endothelial cells.

    PubMed

    Maca, R D; Fry, G L; Hoak, J C

    1978-04-01

    The effects of hydrocortisone, dexamethasone and prednisone on the morphology, replication, DNA synthesis, cell protein content and protein synthesis of cultured, human endothelial cells were evaluated. After culturing the cells with these glucocorticoids for 24-48 h, the cells covered a greater portion of the culture surface area. The mean surface area of the individual endothelial cell treated with glucocorticoids was 1.53 times greater than that of the untreated control endothelial cell. When compared with controls, the endothelial cover provided by the cells treated with glucocorticoids was more extensive and in many instances covered the entire culture surface. The change in morphology was associated with an increase in protein synthesis and protein content of the cells without an increase in DNA synthesis or cellular replication. Dexamethasone was approximately 10-fold more effective than hydrocortisone, while prednisone was the least effective. Aldosterone, DOCA, testosterone, progesterone, oestradiol and oestriol were ineffective. These studies indicate that glucocorticoids can alter the morphology and biochemistry of cultured endothelial cells and may have implications for the effects of steroids in the treatment of thrombocytopenic states and vascular disorders in man. PMID:646949

  17. Rapid flow-induced responses in endothelial cells

    NASA Technical Reports Server (NTRS)

    Stamatas, G. N.; McIntire, L. V.

    2001-01-01

    Endothelial cells alter their morphology, growth rate, and metabolism in response to fluid shear stress. To study rapid flow-induced responses in the 3D endothelial cell morphology and calcium distribution, coupled fluorescence microscopy with optical sectioning, digital imaging, and numerical deconvolution techniques have been utilized. Results demonstrate that within the first minutes of flow application nuclear calcium is increasing. In the same time frame whole cell height and nuclear height are reduced by about 1 microm. Whole cell height changes may facilitate reduction of shear stress gradients on the luminal surface, whereas nuclear structural changes may be important for modulating endothelial growth rate and metabolism. To study the role of the cytoskeleton in these responses, endothelial cells have been treated with specific disrupters (acrylamide, cytochalasin D, and colchicine) of each of the cytoskeleton elements (intermediate filaments, microfilaments, and microtubules, respectively). None of these compounds had any effect on the shear-induced calcium response. Cytochalasin D and acrylamide did not affect the shear-induced nuclear morphology changes. Colchicine, however, completely abrogated the response, indicating that microtubules may be implicated in force transmission from the plasma membrane to the nucleus. A pedagogical model based on tensegrity theory principles is presented that is consistent with the results on the 3D endothelial morphology.

  18. Endothelial Cilia Are Essential for Developmental Vascular Integrity in Zebrafish

    PubMed Central

    Kallakuri, Sowjanya; Yu, Jianxin A.; Li, Jade; Li, Yuanyuan; Weinstein, Brant M.; Nicoli, Stefania

    2015-01-01

    The cilium is a signaling platform of the vertebrate cell. It has a critical role in polycystic kidney disease and nephronophthisis. Cilia have been detected on endothelial cells, but the function of these organelles in the vasculature remains incompletely defined. In this study, using genetic and chemical genetic tools in the model organism zebrafish, we reveal an essential role of cilia in developmental vascular integrity. Embryos expressing mutant intraflagellar transport genes, which are essential and specific for cilia biogenesis, displayed increased risk of developmental intracranial hemorrhage, whereas the morphology of the vasculature remained normal. Moreover, cilia were present on endothelial cells in the developing zebrafish vasculature. We further show that the involvement of cilia in vascular integrity is endothelial autonomous, because endothelial-specific re-expression of intraflagellar transport genes in respective mutants rescued the intracranial hemorrhage phenotype. Finally, whereas inhibition of Hedgehog signaling increased the risk of intracranial hemorrhage in ciliary mutants, activation of the pathway rescued this phenotype. In contrast, embryos expressing an inactivating mutation in pkd2, one of two autosomal dominant cystic kidney disease genes, did not show increased risk of developmental intracranial hemorrhage. These results suggest that Hedgehog signaling is a major mechanism for this novel role of endothelial cilia in establishing vascular integrity. PMID:25214579

  19. Human cultured endothelial cells do secrete endothelin-1

    SciTech Connect

    Clozel, M.; Fischli, W. )

    1989-01-01

    Endothelin-1 (ET-1) has been identified in the conditioned medium of porcine endothelial cells. Human endothelin (ET-1) cloned from a placenta cDNA library is similar to porcine, but it is not known whether endothelin itself is secreted by human endothelial cells. To answer this question, a conditioned medium taken every 48 h from confluent cultures of umbilical vein endothelial cells was analyzed by HPLC and all fractions were tested for their ability to inhibit ({sup 125}I)ET-1 binding on human placenta membranes. Only one fraction did inhibit ({sup 125}I)ET-1 binding. When the conditioned medium was spiked with ET-1, the same single fraction inhibited ({sup 125}I)ET-1 binding showing that ET-1, itself, is present in the conditioned medium of human endothelial cells. ET-1 accumulates with time, reaching a plateau at 48 h. ET-1 secretion is not increased by a 24-h incubation of endothelial cells with phorbol myristate acetate, interleukin-1, tumor necrosis factor, thrombin or neuropeptide Y.

  20. An exquisite cross-control mechanism among endothelial cell fate regulators directs the plasticity and heterogeneity of lymphatic endothelial cells

    PubMed Central

    Kang, Jinjoo; Yoo, Jaehyuk; Lee, Sunju; Tang, Wanli; Aguilar, Berenice; Ramu, Swapnika; Choi, Inho; Otu, Hasan H.; Shin, Jay W.; Dotto, G. Paolo; Koh, Chester J.; Detmar, Michael

    2010-01-01

    Arteriovenous-lymphatic endothelial cell fates are specified by the master regulators, namely, Notch, COUP-TFII, and Prox1. Whereas Notch is expressed in the arteries and COUP-TFII in the veins, the lymphatics express all 3 cell fate regulators. Previous studies show that lymphatic endothelial cell (LEC) fate is highly plastic and reversible, raising a new concept that all 3 endothelial cell fates may coreside in LECs and a subtle alteration can result in a reprogramming of LEC fate. We provide a molecular basis verifying this concept by identifying a cross-control mechanism among these cell fate regulators. We found that Notch signal down-regulates Prox1 and COUP-TFII through Hey1 and Hey2 and that activated Notch receptor suppresses the lymphatic phenotypes and induces the arterial cell fate. On the contrary, Prox1 and COUP-TFII attenuate vascular endothelial growth factor signaling, known to induce Notch, by repressing vascular endothelial growth factor receptor-2 and neuropilin-1. We show that previously reported podoplanin-based LEC heterogeneity is associated with differential expression of Notch1 in human cutaneous lymphatics. We propose that the expression of the 3 cell fate regulators is controlled by an exquisite feedback mechanism working in LECs and that LEC fate is a consequence of the Prox1-directed lymphatic equilibrium among the cell fate regulators. PMID:20351309

  1. An Antagonistic Vascular Endothelial Growth Factor (VEGF) Variant Inhibits VEGF-Stimulated Receptor Autophosphorylation and Proliferation of Human Endothelial Cells

    NASA Astrophysics Data System (ADS)

    Siemeister, Gerhard; Schirner, Michael; Reusch, Petra; Barleon, Bernhard; Marme, Dieter; Martiny-Baron, Georg

    1998-04-01

    Vascular endothelial growth factor (VEGF) is a potent mitogen with a unique specificity for endothelial cells and a key mediator of aberrant endothelial cell proliferation and vascular permeability in a variety of human pathological situations, such as tumor angiogenesis, diabetic retinopathy, rheumatoid arthritis, or psoriasis. VEGF is a symmetric homodimeric molecule with two receptor binding interfaces lying on each pole of the molecule. Herein we report on the construction and recombinant expression of an asymmetric heterodimeric VEGF variant with an intact receptor binding interface at one pole and a mutant receptor binding interface at the second pole of the dimer. This VEGF variant binds to VEGF receptors but fails to induce receptor activation. In competition experiments, the heterodimeric VEGF variant antagonizes VEGF-stimulated receptor autophosphorylation and proliferation of endothelial cells. A 15-fold excess of the heterodimer was sufficient to inhibit VEGF-stimulated endothelial cell proliferation by 50%, and a 100-fold excess resulted in an almost complete inhibition. By using a rational approach that is based on the structure of VEGF, we have shown the feasibility to construct a VEGF variant that acts as an VEGF antagonist.

  2. Interleukin 3 stimulates proliferation and triggers endothelial-leukocyte adhesion molecule 1 gene activation of human endothelial cells.

    PubMed

    Brizzi, M F; Garbarino, G; Rossi, P R; Pagliardi, G L; Arduino, C; Avanzi, G C; Pegoraro, L

    1993-06-01

    Proliferation and functional activation of endothelial cells within a tissue site of inflammation are regulated by humoral factors released by cells, such as T lymphocytes and monocytes, infiltrating the perivascular space. In the present study we investigated the effects of interleukin 3 (IL-3), an activated T lymphocyte-derived cytokine, on cultured human umbilical vein endothelial cells (HUVEC). Proliferative activity, evaluated both by estimation of the fraction of cells in the S phase and by direct cell count demonstrated that IL-3, at the dose of 25 ng/ml, enhances more than threefold both DNA synthesis and cell proliferation above baseline control conditions. Binding studies with radioiodinated ligand demonstrated that HUVEC constitutively express a smaller number of IL-3 binding sites (approximately 99 binding sites per cell, with an apparent Kd of 149 pM). Accordingly, molecular analysis showed the presence of transcripts for both alpha and beta subunits of the IL-3 receptor. Functional activation of endothelial cells was evaluated by the expression of the endothelial-leukocyte adhesion molecule 1 (ELAM-1) transcript and by leukocyte adhesion. The ELAM-1 gene transcript was clearly detectable 4 h after IL-3 addition and started to decrease after 12 h. Moreover, IL-3-induced ELAM-1 transcription was followed by enhanced adhesion of neutrophils and CD4+ T cells to HUVEC. The findings that IL-3 can stimulate both proliferation and functional activation of endothelial cells suggest that this cytokine can be involved in sustaining the process of chronic inflammation.

  3. In vivo modulation of endothelial polarization by Apelin receptor signalling

    PubMed Central

    Kwon, Hyouk-Bum; Wang, Shengpeng; Helker, Christian S. M.; Rasouli, S. Javad; Maischein, Hans-Martin; Offermanns, Stefan; Herzog, Wiebke; Stainier, Didier Y. R.

    2016-01-01

    Endothelial cells (ECs) respond to shear stress by aligning in the direction of flow. However, how ECs respond to flow in complex in vivo environments is less clear. Here we describe an endothelial-specific transgenic zebrafish line, whereby the Golgi apparatus is labelled to allow for in vivo analysis of endothelial polarization. We find that most ECs polarize within 4.5 h after the onset of vigorous blood flow and, by manipulating cardiac function, observe that flow-induced EC polarization is a dynamic and reversible process. Based on its role in EC migration, we analyse the role of Apelin signalling in EC polarization and find that it is critical for this process. Knocking down Apelin receptor function in human primary ECs also affects their polarization. Our study provides new tools to analyse the mechanisms of EC polarization in vivo and reveals an important role in this process for a signalling pathway implicated in cardiovascular disease. PMID:27248505

  4. Molecular control of endothelial cell behaviour during blood vessel morphogenesis

    PubMed Central

    Herbert, Shane P.; Stainier, Didier Y.R.

    2012-01-01

    The vertebrate vasculature forms an extensive branched network of blood vessels that supplies tissues with nutrients and oxygen. During vascular development, coordinated control of endothelial cell behaviour at the levels of cell migration, proliferation, polarity, differentiation and cell–cell communication is critical for functional blood vessel morphogenesis. Recent data uncover elaborate transcriptional, post-transcriptional and post-translational mechanisms that fine-tune key signalling pathways (such as the vascular endothelial growth factor and Notch pathways) to control endothelial cell behaviour during blood vessel sprouting (angiogenesis). These emerging frameworks controlling angiogenesis provide unique insights into fundamental biological processes common to other systems, such as tissue branching morphogenesis, mechanotransduction and tubulogenesis. PMID:21860391

  5. [Pulmonary arterial hypertension, bone marrow, endothelial cell precursors and serotonin].

    PubMed

    Ayme-Dietrich, Estelle; Banas, Sophie M; Monassier, Laurent; Maroteaux, Luc

    2016-01-01

    Serotonin and bone-marrow-derived stem cells participate together in triggering pulmonary hypertension. Our work has shown that the absence of 5-HT2B receptors generates permanent changes in the composition of the blood and bone-marrow in the myeloid lineages, particularly in endothelial cell progenitors. The initial functions of 5-HT2B receptors in pulmonary arterial hypertension (PAH) are restricted to bone-marrow cells. They contribute to the differentiation/proliferation/mobilization of endothelial progenitor cells from the bone-marrow. Those bone-marrow-derived cells have a critical role in the development of pulmonary hypertension and pulmonary vascular remodeling. These data indicate that bone-marrow derived endothelial progenitors play a key role in the pathogenesis of PAH and suggest that interactions involving serotonin and bone morphogenic protein type 2 receptor (BMPR2) could take place at the level of the bone-marrow. PMID:27687599

  6. Mechanisms for SU5416 as a radiosensitizer of endothelial cells.

    PubMed

    Kim, Eun Ho; Kim, Mi-Sook; Jeong, Youn Kyoung; Cho, Ilsung; You, Seung Hoon; Cho, Sung Ho; Lee, Hanna; Jung, Won-Gyun; Kim, Hag Dong; Kim, Joon

    2015-10-01

    Endothelial cells (ECs), that comprise the tumor vasculature, are critical targets for anticancer radiotherapy. The aim of this work was to study the mechanism by which SU5416, a known anti-angiogenesis inhibitor, modifies the radiation responses of human vascular ECs. Two human endothelial cell lines (HUVEC and 2H11) were treated with SU5416 alone, radiation alone, or a combination of both. In vitro tests were performed using colony forming assays, FACS analysis, western blotting, immunohistochemistry, migration assay, invasion assays and endothelial tube formation assays. The combination of radiation and SU5416 significantly inhibited cell survival, the repair of radiation-induced DNA damage, and induced apoptosis. It also caused cell cycle arrest, inhibited cell migration and invasion, and suppressed angiogenesis. In this study, our results first provide a scientific rationale to combine SU5416 with radiotherapy to target ECs and suggest its clinical application in combination cancer treatment with radiotherapy.

  7. Influence of food patterns on endothelial biomarkers: a systematic review

    PubMed Central

    Defagó; Elorriaga, N; Irazola, VE; Rubinstein, AL

    2014-01-01

    The purpose of this study was to conduct a systematic review on the association of food patterns (FPs) and endothelial biomarkers. An electronic literature search from 1990–2012 was conducted and reference lists and experts were consulted. Studies without dietary intervention and without language restrictions were considered. PRISMA guidelines were employed. Methodological quality was assessed by STROBE. 546 references were identified, out of which 8 were finally included. Several FPs were identified. Healthy FPs (abundant in fruits and vegetables) had a beneficial impact on endothelial function as estimated by circulating levels of biomarkers such as CRP, sICAM-1, sVCAM-1 and sSELE molecules. Westernized patterns (higher intakes of processed meats, sweets, fried foods, and refined grains) were positively associated to inflammation molecules and atherogenic promoters. The study of FPs in relation to endothelial function contributes to the development of dietary recommendations for an improved cardiovascular health and therefore a better lifestyle. PMID:25376124

  8. Brain endothelial TAK1 and NEMO safeguard the neurovascular unit

    PubMed Central

    Ridder, Dirk A.; Wenzel, Jan; Müller, Kristin; Töllner, Kathrin; Tong, Xin-Kang; Assmann, Julian C.; Stroobants, Stijn; Weber, Tobias; Niturad, Cristina; Fischer, Lisanne; Lembrich, Beate; Wolburg, Hartwig; Grand’Maison, Marilyn; Papadopoulos, Panayiota; Korpos, Eva; Truchetet, Francois; Rades, Dirk; Sorokin, Lydia M.; Schmidt-Supprian, Marc; Bedell, Barry J.; Pasparakis, Manolis; Balschun, Detlef; D’Hooge, Rudi; Löscher, Wolfgang; Hamel, Edith

    2015-01-01

    Inactivating mutations of the NF-κB essential modulator (NEMO), a key component of NF-κB signaling, cause the genetic disease incontinentia pigmenti (IP). This leads to severe neurological symptoms, but the mechanisms underlying brain involvement were unclear. Here, we show that selectively deleting Nemo or the upstream kinase Tak1 in brain endothelial cells resulted in death of endothelial cells, a rarefaction of brain microvessels, cerebral hypoperfusion, a disrupted blood–brain barrier (BBB), and epileptic seizures. TAK1 and NEMO protected the BBB by activating the transcription factor NF-κB and stabilizing the tight junction protein occludin. They also prevented brain endothelial cell death in a NF-κB–independent manner by reducing oxidative damage. Our data identify crucial functions of inflammatory TAK1–NEMO signaling in protecting the brain endothelium and maintaining normal brain function, thus explaining the neurological symptoms associated with IP. PMID:26347470

  9. Assessing vascular endothelial function using frequency and rank order statistics

    NASA Astrophysics Data System (ADS)

    Wu, Hsien-Tsai; Hsu, Po-Chun; Sun, Cheuk-Kwan; Liu, An-Bang; Lin, Zong-Lin; Tang, Chieh-Ju; Lo, Men-Tzung

    2013-08-01

    Using frequency and rank order statistics (FROS), this study analyzed the fluctuations in arterial waveform amplitudes recorded from an air pressure sensing system before and after reactive hyperemia (RH) induction by temporary blood flow occlusion to evaluate the vascular endothelial function of aged and diabetic subjects. The modified probability-weighted distance (PWD) calculated from the FROS was compared with the dilatation index (DI) to evaluate its validity and sensitivity in the assessment of vascular endothelial function. The results showed that the PWD can provide a quantitative determination of the structural changes in the arterial pressure signals associated with regulation of vascular tone and blood pressure by intact vascular endothelium after the application of occlusion stress. Our study suggests that the use of FROS is a reliable noninvasive approach to the assessment of vascular endothelial degeneration in aging and diabetes.

  10. Dynamic Endothelial Cell Rearrangements Drive Developmental Vessel Regression

    PubMed Central

    Franco, Claudio A.; Jones, Martin L.; Bernabeu, Miguel O.; Geudens, Ilse; Mathivet, Thomas; Rosa, Andre; Lopes, Felicia M.; Lima, Aida P.; Ragab, Anan; Collins, Russell T.; Phng, Li-Kun; Coveney, Peter V.; Gerhardt, Holger

    2015-01-01

    Patterning of functional blood vessel networks is achieved by pruning of superfluous connections. The cellular and molecular principles of vessel regression are poorly understood. Here we show that regression is mediated by dynamic and polarized migration of endothelial cells, representing anastomosis in reverse. Establishing and analyzing the first axial polarity map of all endothelial cells in a remodeling vascular network, we propose that balanced movement of cells maintains the primitive plexus under low shear conditions in a metastable dynamic state. We predict that flow-induced polarized migration of endothelial cells breaks symmetry and leads to stabilization of high flow/shear segments and regression of adjacent low flow/shear segments. PMID:25884288

  11. Descemet's Stripping Automated Endothelial Keratoplasty Tissue Insertion Devices

    PubMed Central

    Khan, Salman Nasir; Shiakolas, Panos S.; Mootha, Venkateswara Vinod

    2015-01-01

    This review study provides information regarding the construction, design, and use of six commercially available endothelial allograft insertion devices applied for Descemet's stripping automated endothelial keratoplasty (DSAEK). We also highlight issues being faced in DSAEK and discuss the methods through which medical devices such as corneal inserters may alleviate these issues. Inserter selection is of high importance in the DSAEK procedure since overcoming the learning curve associated with the use of an insertion device is a time and energy consuming process. In the present review, allograft insertion devices were compared in terms of design, construction material, insertion technique, dimensions, incision requirements and endothelial cell loss to show their relative merits and capabilities based on available data in the literature. Moreover, the advantages/disadvantages of various insertion devices used for allograft insertion in DSAEK are reviewed and compared. The information presented in this review can be utilized for better selection of an insertion device for DSAEK. PMID:27051492

  12. Anti-endothelial antibodies and neuropsychiatric systemic lupus erythematosus.

    PubMed

    Valesini, Guido; Alessandri, Cristiano; Celestino, Domenico; Conti, Fabrizio

    2006-06-01

    The pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) has been attributed to autoantibody-mediated neural dysfunction, vasculopathy, and coagulopathy. Several autoantibodies specificities have been reported in serum and cerebrospinal fluid of NPSLE patients (i.e., antineuronal, antiribosomal P proteins, antiglial fibrillary acidic proteins, antiphospholipid, and anti-endothelial antibodies). We have recently demonstrated an association between serum anti-endothelial antibodies and psychosis or depression in patients with SLE. Subsequently, by screening a cDNA library from human umbilical artery endothelial cells with serum from a SLE patient with psychosis, one positive strongly reactive clone was identified encoding the C-terminal region (C-ter) of Nedd5, an intracytoplasmatic protein of the septin family. Anti-Nedd5 antibodies have been found significantly associated with psychiatric manifestations in SLE patients, strengthening the view of a possible implication of autoantibodies in the development of psychiatric disorders.

  13. Endothelial progenitor cells and burn injury - exploring the relationship.

    PubMed

    Banyard, Derek A; Adnani, Blake O; Melkumyan, Satenik; Araniego, Cheryl Ann; Widgerow, Alan D

    2016-01-01

    Burn wounds result in varying degrees of soft tissue damage that are typically graded clinically. Recently a key participant in neovascularization, the endothelial progenitor cell, has been the subject of intense cardiovascular research to explore whether it can serve as a biomarker for vascular injury. In this review, we examine the identity of the endothelial progenitor cell as well as the evidence that support its role as a key responder after burn insult. While there is conflicting evidence with regards to the delta of endothelial progenitor cell mobilization and burn severity, it is clear that they play an important role in wound healing. Systematic and controlled studies are needed to clarify this relationship, and whether this population can serve as a biomarker for burn severity. PMID:27574674

  14. Brassinosteroids inhibit in vitro angiogenesis in human endothelial cells.

    PubMed

    Rárová, Lucie; Zahler, Stefan; Liebl, Johanna; Kryštof, Vladimír; Sedlák, David; Bartůněk, Petr; Kohout, Ladislav; Strnad, Miroslav

    2012-11-01

    Antiangiogenic activity of the brassinosteroid plant hormones (BRs) and their derivative cholestanon was investigated in human umbilical vein endothelial cells (HUVEC) and in human microvascular endothelial cells (HMEC-1). 24-Epibrassinolide and 28-homocastasterone from group of 21 tested natural BRs inhibited migration of HUVEC cells. Seven tested BRs decreased the number of tubes significantly. Synthetic analogue cholestanon inhibited angiogenesis in vitro more effectively than natural BRs. Because of the similarity of BRs to human steroids, we have also studied interactions of BRs with human steroid receptors. Synthetic BRs cholestanon showed agonistic effects on estrogen-receptor-α, estrogen-receptor-β and androgen receptor. Of the natural BRs, 24-epibrassinolide was found to be a weak antagonist of estrogen-receptor-α (ERα). Our results provide the first evidence that large group of BRs can inhibit in vitro angiogenesis of primary endothelial cells. BRs constitute a novel group of human steroid receptor activators or inhibitors with capacity to inhibit angiogenesis.

  15. [Endothelial glycocalyx of blood circulation. I. Finding, components, structure organization].

    PubMed

    Maksimenko, A V; Turashev, A D

    2014-01-01

    In normal state, a complex multicomponent system called glycocalyx is present on the surface of endothelial vascular system. The structure of the glycocalyx is determined by a group ofproteoglycans, glycoproteins and glycosaminoglycans, originating from endothelial cells and blood flow. Due to its complexity and location on the border of the system of blood circulation, glycocalyx participates in a number of functions supporting the metabolism of the vascular wall. Complete or partial loss of this structure in pathologicalconditions leads to inconsistencies in the vascular wall and changes in its functions. The first part of this review considers the history of detection and determination of endothelial glycocalyx structure, utilized methods and approaches. The molecular composition of the glycocalyx, properties of its components and glycocalyx structure organization are described. The English version of the paper: Russian Journal of Bioorganic Chemistry, see also http://www.maik.ru.

  16. Principles of targeting endothelial cell metabolism to treat angiogenesis and endothelial cell dysfunction in disease

    PubMed Central

    Goveia, Jermaine; Stapor, Peter; Carmeliet, Peter

    2014-01-01

    The endothelium is the orchestral conductor of blood vessel function. Pathological blood vessel formation (a process termed pathological angiogenesis) or the inability of endothelial cells (ECs) to perform their physiological function (a condition known as EC dysfunction) are defining features of various diseases. Therapeutic intervention to inhibit aberrant angiogenesis or ameliorate EC dysfunction could be beneficial in diseases such as cancer and cardiovascular disease, respectively, but current strategies have limited efficacy. Based on recent findings that pathological angiogenesis and EC dysfunction are accompanied by EC-specific metabolic alterations, targeting EC metabolism is emerging as a novel therapeutic strategy. Here, we review recent progress in our understanding of how EC metabolism is altered in disease and discuss potential metabolic targets and strategies to reverse EC dysfunction and inhibit pathological angiogenesis. PMID:25063693

  17. Toll-like receptor 4-induced endoplasmic reticulum stress contributes to endothelial dysfunction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Impairment of vasodilator action of insulin is associated with endothelial dysfunction and insulin resistance. Endoplasmic reticulum (ER) stress is implicated as one of the mechanisms for pathophysiology of various cardiometabolic syndromes, including insulin resistance and endothelial dysfunction. ...

  18. Phosphorylated endothelial nitric oxide synthase mediates vascular endothelial growth factor-induced penile erection.

    PubMed

    Musicki, Biljana; Palese, Michael A; Crone, Julie K; Burnett, Arthur L

    2004-02-01

    The objective of the present study was to evaluate whether vascular endothelial growth factor (VEGF)-induced penile erection is mediated by activation of endothelial nitric oxide synthase (eNOS) through its phosphorylation. We assessed the role of constitutively activated eNOS in VEGF-induced penile erection using wild-type (WT) and eNOS-knockout (eNOS(-/-)) mice with and without vasculogenic erectile dysfunction. Adult WT and eNOS(-/-) mice were subjected to sham operation or bilateral castration to induce vasculogenic erectile dysfunction. At the time of surgery, animals were injected intracavernosally with a replication-deficient adenovirus expressing human VEGF145 (10(9) particle units) or with empty virus (Ad.Null). After 7 days, erectile function was assessed in response to cavernous nerve electrical stimulation. Total and phosphorylated protein kinase B (Akt) as well as total and phosphorylated eNOS were quantitatively assessed in mice penes using Western immunoblot and immunohistochemistry. In intact WT mice, VEGF145 significantly increased erectile responses, and in WT mice after castration, it completely recovered penile erection. However, VEGF145 failed to increase erectile responses in intact eNOS(-/-) mice and only partially recovered erectile function in castrated eNOS(-/-) mice. In addition, VEGF145 significantly increased phosphorylation of eNOS at Serine 1177 by approximately 2-fold in penes of both intact and castrated WT mice. The data provide a molecular explanation for VEGF stimulatory effect on penile erection, which involves phosphorylated eNOS (Serine 1177) mediation. PMID:14522830

  19. Adhesion behavior of endothelial progenitor cells to endothelial cells in simple shear flow

    NASA Astrophysics Data System (ADS)

    Gong, Xiao-Bo; Li, Yu-Qing; Gao, Quan-Chao; Cheng, Bin-Bin; Shen, Bao-Rong; Yan, Zhi-Qiang; Jiang, Zong-Lai

    2011-12-01

    The adhesion of endothelial progenitor cells (EPCs) on endothelial cells (ECs) is one of the critical physiological processes for the regenesis of vascular vessels and the prevention of serious cardiovascular diseases. Here, the rolling and adhesion behavior of EPCs on ECs was studied numerically. A two-dimensional numerical model was developed based on the immersed boundary method for simulating the rolling and adhesion of cells in a channel flow. The binding force arising from the catch bond of a receptor and ligand pair was modeled with stochastic Monte Carlo method and Hookean spring model. The effect of tumor necrosis factor alpha (TNF- α) on the expression of the number of adhesion molecules in ECs was analyzed experimentally. A flow chamber system with CCD camera was set up to observe the top view of the rolling of EPCs on the substrate cultivated with ECs. Numerical results prove that the adhesion of EPC on ECs is closely related to membrane stiffness of the cell and shear rate of the flow. It also suggests that the adhesion force between EPC and EC by P-selectin glycoprotein ligand-1 only is not strong enough to bond the cell onto vessel walls unless contributions of other catch bond are considered. Experimental results demonstrate that TNF- α enhanced the expressions of VCAM, ICAM, P-selectin and E-selectin in ECs, which supports the numerical results that the rolling velocity of EPC on TNF- α treated EC substrate decreases obviously compared with its velocity on the untreated one. It is found that because the adhesion is affected by both the rolling velocity and the deformability of the cell, an optimal stiffness of EPC may exist at a given shear rate of flow for achieving maximum adhesion rates.

  20. Mussel-inspired immobilization of vascular endothelial growth factor (VEGF) for enhanced endothelialization of vascular grafts.

    PubMed

    Shin, Young Min; Lee, Yu Bin; Kim, Seok Joo; Kang, Jae Kyeong; Park, Jong-Chul; Jang, Wonhee; Shin, Heungsoo

    2012-07-01

    Most polymeric vascular prosthetic materials have low patency rate for replacement of small diameter vessels (<5 mm), mainly due to failure to generate healthy endothelium. In this study, we present polydopamine-mediated immobilization of growth factors on the surface of polymeric materials as a versatile tool to modify surface characteristics of vascular grafts potentially for accelerated endothelialization. Polydopamine was deposited on the surface of biocompatible poly(L-lactide-co-ε-caprolactone) (PLCL) elastomer, on which vascular endothelial growth factor (VEGF) was subsequently immobilized by simple dipping. Surface characteristics and composition were investigated by using scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Immobilization of VEGF on the polydopamine-deposited PLCL films was effective (19.8 ± 0.4 and 197.4 ± 19.7 ng/cm(2) for DPv20 and DPv200 films, respectively), and biotin-mediated labeling of immobilized VEGF revealed that the fluorescence intensity increased as a function of the concentration of VEGF solution. The effect of VEGF on adhesion of HUVECs was marginal, which may have been masked by polydopamine layer that also enhanced cell adhesion. However, VEGF-immobilized substrate significantly enhanced proliferation of HUVECs for over 7 days of in vitro culture and also improved their migration. In addition, immobilized VEGF supported robust cell to cell interactions with strong expression of CD 31 marker. The same process was effective for immobilization of basic fibroblast growth factor, demonstrating the robustness of polydopamine layer for secondary ligation of growth factors as a simple and novel surface modification strategy for vascular graft materials. PMID:22617001

  1. Vascular endothelial platelet endothelial cell adhesion molecule 1 (PECAM-1) regulates advanced metastatic progression

    PubMed Central

    DeLisser, Horace; Liu, Yong; Desprez, Pierre-Yves; Thor, Ann; Briasouli, Paraskevei; Handumrongkul, Chakrapong; Wilfong, Jonathon; Yount, Garret; Nosrati, Mehdi; Fong, Sylvia; Shtivelman, Emma; Fehrenbach, Melane; Cao, Gaoyuan; Moore, Dan H.; Nayak, Shruti; Liggitt, Denny; Kashani-Sabet, Mohammed; Debs, Robert

    2010-01-01

    Most patients who die from cancer succumb to treatment-refractory advanced metastatic progression. Although the early stages of tumor metastasis result in the formation of clinically silent micrometastatic foci, its later stages primarily reflect the progressive, organ-destructive growth of already advanced metastases. Early-stage metastasis is regulated by multiple factors within tumor cells as well as by the tumor microenvironment (TME). In contrast, the molecular determinants that control advanced metastatic progression remain essentially uncharacterized, precluding the development of therapies targeted against it. Here we show that the TME, functioning in part through platelet endothelial cell adhesion molecule 1 (PECAM-1), drives advanced metastatic progression and is essential for progression through its preterminal end stage. PECAM-1–KO and chimeric mice revealed that its metastasis-promoting effects are mediated specifically through vascular endothelial cell (VEC) PECAM-1. Anti–PECAM-1 mAb therapy suppresses both end-stage metastatic progression and tumor-induced cachexia in tumor-bearing mice. It reduces proliferation, but not angiogenesis or apoptosis, within advanced tumor metastases. Because its antimetastatic effects are mediated by binding to VEC rather than to tumor cells, anti–PECAM-1 mAb appears to act independently of tumor type. A modified 3D coculture assay showed that anti–PECAM-1 mAb inhibits the proliferation of PECAM-1–negative tumor cells by altering the concentrations of secreted factors. Our studies indicate that a complex interplay between elements of the TME and advanced tumor metastases directs end-stage metastatic progression. They also suggest that some therapeutic interventions may target late-stage metastases specifically. mAb-based targeting of PECAM-1 represents a TME-targeted therapeutic approach that suppresses the end stages of metastatic progression, until now a refractory clinical entity. PMID:20926749

  2. Phosphorylated endothelial nitric oxide synthase mediates vascular endothelial growth factor-induced penile erection.

    PubMed

    Musicki, Biljana; Palese, Michael A; Crone, Julie K; Burnett, Arthur L

    2004-02-01

    The objective of the present study was to evaluate whether vascular endothelial growth factor (VEGF)-induced penile erection is mediated by activation of endothelial nitric oxide synthase (eNOS) through its phosphorylation. We assessed the role of constitutively activated eNOS in VEGF-induced penile erection using wild-type (WT) and eNOS-knockout (eNOS(-/-)) mice with and without vasculogenic erectile dysfunction. Adult WT and eNOS(-/-) mice were subjected to sham operation or bilateral castration to induce vasculogenic erectile dysfunction. At the time of surgery, animals were injected intracavernosally with a replication-deficient adenovirus expressing human VEGF145 (10(9) particle units) or with empty virus (Ad.Null). After 7 days, erectile function was assessed in response to cavernous nerve electrical stimulation. Total and phosphorylated protein kinase B (Akt) as well as total and phosphorylated eNOS were quantitatively assessed in mice penes using Western immunoblot and immunohistochemistry. In intact WT mice, VEGF145 significantly increased erectile responses, and in WT mice after castration, it completely recovered penile erection. However, VEGF145 failed to increase erectile responses in intact eNOS(-/-) mice and only partially recovered erectile function in castrated eNOS(-/-) mice. In addition, VEGF145 significantly increased phosphorylation of eNOS at Serine 1177 by approximately 2-fold in penes of both intact and castrated WT mice. The data provide a molecular explanation for VEGF stimulatory effect on penile erection, which involves phosphorylated eNOS (Serine 1177) mediation.

  3. Regulation of human endothelial progenitor cell maturation by polyurethane nanocomposites.

    PubMed

    Hung, Huey-Shan; Yang, Yi-Chun; Lin, Yu-Chun; Lin, Shinn-Zong; Kao, Wei-Chien; Hsieh, Hsien-Hsu; Chu, Mei-Yun; Fu, Ru-Huei; Hsu, Shan-hui

    2014-08-01

    The mobilization and homing of endothelial progenitor cells (EPCs) are critical to the development of an antithrombotic cardiovascular prosthesis. Polyurethane (PU) with superior elasticity may provide a mechanical environment resembling that of the natural vascular tissues. The topographical cues of PU were maximized by making nanocomposites with a small amount of gold nanoparticles (AuNPs). The nanocomposites of PU-AuNPs ("PU-Au") with a favorable response of endothelial cells were previously established. In the current study, the effect of PU and PU-Au nanocomposites on the behavior of human peripheral blood EPCs was investigated in vitro and in vivo. It was found that PU-Au promoted EPCs to become differentiated endothelial cells in vitro, confirmed by the increased expressions of CD31 and VEGF-R2 surface markers. The increased maturation of EPCs was significantly more remarkable on PU-Au, probably through the stromal derived factor 1α (SDF-1α)/CXCR4 signaling pathway. In vivo experiments showed that EPCs seeded on PU-Au coated catheters effectively reduced thrombosis by differentiation into endothelial cells. Surface endothelialization with CD31 and CD34 expression as well as intimal formation with α-SMA expression was significantly accelerated in the group receiving EPC-seeded PU-Au catheters. Moreover, the analysis of collagen deposition revealed a reduction of fibrosis in the group receiving EPC-seeded PU-Au catheters as compared to the other groups. These results suggest that EPCs engineered with a proper elastic substrate may provide unique endothelialization and antithrombogenic properties that benefit vascular tissue regeneration. PMID:24836305

  4. Prolonged organ culture reduces the incidence of endothelial immune reactions.

    PubMed

    Maier, P; Heinzelmann, S; Böhringer, D; Reinhard, T

    2016-01-01

    PURPOSE The number of antigen-presenting cells decreases during organ culture of corneoscleral discs. This might result in a decrease of immune reactions with increasing duration of organ culture. To investigate this hypothesis, we performed a retrospective analysis of all penetrating keratoplasties that were consecutively performed over the last 5 years.PATIENTS AND METHODS All cases of penetrating keratoplasties (n=1006) were divided into two groups, with the division made at the median of the storage time (21 days). These two groups were compared by a Cox proportional hazards survival model regarding the incidence of endothelial immune reactions, clear graft survival, and chronic endothelial cell loss following penetrating keratoplasty considering patient's age, donor's age, and risk situation as co-variates.RESULTS We observed statistically significantly fewer endothelial immune reactions (20.1% (95% confidence interval 15.5-24.5%) after 2 years) in the group with a storage time of more than 21 days compared with the group with a storage time of <21 days (26.5% (95% confidence interval 21.6-31.2%) after 2 years). However, the duration of organ culture did not have a statistically significant effect on clear graft survival or chronic endothelial cell loss.CONCLUSION Our results demonstrate that an increased duration of organ culture leads to a lower incidence of endothelial immune reactions following penetrating keratoplasty. However, we do not recommend increased storage times in general as overall graft survival did not improve. The reason for this apparent paradox may be that the endothelial cell count decreases during storage time. PMID:26493031

  5. Binding of ATGs to Endothelial Cells In Vivo.

    PubMed

    Beiras-Fernandez, Andres; Hernandez-Sierra, Astrid; Schulz, Uwe; Richter, Manfred; Thein, Eckart; Moritz, Anton; Werner, Isabella

    2016-05-17

    BACKGROUND Polyclonal anti-thymocyte globulins (ATGs) are immunosuppressive drugs widely used in induction of immunosuppression and treatment of acute rejection after solid organ transplantation. We have previously demonstrated that ATGs bind to endothelial cells in vitro, and are able to modulate ECs. The aim of this study was to investigate the binding of ATGs to endothelial cells under in vivo conditions. MATERIAL AND METHODS Muscle biopsies from extremities of cynomolgus monkeys were obtained after ischemia/reperfusion at 4°C. ATGs (Thymoglobulin, Sanofi-Aventis, France; 1 mg/kg) were added to the blood 30 min prior to the reperfusion. Biopsies (n=10) of patients undergoing heart transplantation and preoperatively treated with ATGs (Thymoglobulin, Sanofi-Aventis, France; 1.5 mg/kg) as induction therapy were also analyzed 6 hours and 7 days after induction. Binding of ATGs to ECs was analyzed with an anti-rabbit IgG antibody by means of immunohistochemistry. RESULTS Binding of ATGs to endothelial cells could be demonstrated in vivo in our animal experiments 4 hours after reperfusion, as well as in the clinical biopsies 6 hours after induction of immunosuppression in heart transplant patients, showing a preferred localization in post-capillary veins. No expression of ATGs on the endothelial surface could be observed after 7 days, suggesting that ATGs may be washed out from the endothelial surface in a time-dependent manner. CONCLUSIONS Our results show that ATGs are able to bind to endothelial cells in an experimental model and in clinical practice, supporting preconditioning strategies with ATGs in solid organ transplantation.

  6. Mineralocorticoid Receptors Modulate Vascular Endothelial Function in Human Obesity

    PubMed Central

    Hwang, Moon-Hyon; Yoo, Jeung-Ki; Luttrell, Meredith; Kim, Han-Kyul; Meade, Thomas H.; English, Mark; Segal, Mark S.; Christou, Demetra D.

    2015-01-01

    Obesity increases linearly with age and is associated with impaired vascular endothelial function and increased risk for cardiovascular disease. Mineralocorticoid receptors (MR) contribute to impaired vascular endothelial function in cardiovascular disease; however, their role in uncomplicated human obesity is unknown. Because plasma aldosterone levels are elevated in obesity and adipocytes may be a source of aldosterone, we hypothesized that MR modulate vascular endothelial function in older adults in an adiposity-dependent manner. To test this hypothesis, we administered MR blockade (Eplerenone; 100 mg/day) for 1 month in a balanced, randomized, double-blind, placebo-controlled, crossover study to 22 older adults (10 men, 55–79 years) varying widely in adiposity (body mass index: 20–45 kg/m2) but who were free from overt cardiovascular disease. We evaluated vascular endothelial function (brachial artery flow-mediated dilation [FMD] via ultrasonography) and oxidative stress (plasma F2-isoprostanes and vascular endothelial cell protein expression of nitrotyrosine and NADPH oxidase p47phox) during placebo and MR blockade. In the whole group, oxidative stress (P>0.05) and FMD did not change with MR blockade (6.39±0.67 vs. 6.23±0.73 %, P=0.7, placebo vs. Eplerenone). However, individual improvements in FMD in response to Eplerenone were associated with higher total body fat (body mass index: r=0.45, P=0.02 and DXA-derived % body fat: r=0.50, P=0.009) and abdominal fat (total: r=0.61, P=0.005, visceral: r=0.67, P=0.002 and subcutaneous: r=0.48, P=0.03). In addition, greater improvements in FMD with Eplerenone were related with higher baseline fasting glucose (r=0.53, P=0.01). MR influence vascular endothelial function in an adiposity-dependent manner in healthy older adults. PMID:23786536

  7. Differential radiation response of cultured endothelial cells and smooth myocytes

    SciTech Connect

    Johnson, L.K.; Longenecker, J.P.; Fajardo, L.F.

    1982-09-01

    In vivo observations have suggested that endothelial cells are the most radiosensitive elements of the vascular wall. To test whether this represents an intrinsic differential sensitivity, the response of bovine aortic endothelial cells and smooth myocytes was investigated in confluent cell cultures exposed to single doses of gamma radiation (250, 500, 1,000 or 2,000 rad). Both cell types showed a dose-dependent decrease in attachment efficiency when dissociated and replated at six hours after radiation. However, the attachment efficiency in both cell types was similar when a 72-hour postirradiation incubation period was used prior to dissociation of the cells. Growth inhibition was significantly greater (7- to 10-fold) in endothelial cells than in myocytes when examined four days after attachment. Confluent endothelial monolayers showed a dose-dependent, progressive cell loss during the 72-hour postirradiation period (70% after 1,000 rad); the myocyte cultures showed no radiation effect on the cell numbers. In spite of the reduction in number, the endothelial cells maintained the continuity of their monolayer by compensation with an increase in mean cell size. Endothelial cells developed multiple structural lesions, including an increase in the number and size of residual and lysosomal bodies, electron-lucent cytoplasmic defects, interruptions in the plasma membrane and irregular aggregation of chromatin, causing electron-lucent nuclei. These changes increased in severity with time and dose and were most pronounced 24 to 72 hours after 1,000 rad. No significant ultrastructural alterations were detected in myocytes four days after 2,000 rad.

  8. Role of the Retinal Vascular Endothelial Cell in Ocular Disease

    PubMed Central

    Bharadwaj, Arpita S.; Appukuttan, Binoy; Wilmarth, Phillip A.; Pan, Yuzhen; Stempel, Andrew J.; Chipps, Timothy J.; Benedetti, Eric E.; Zamora, David O.; Choi, Dongseok; David, Larry L.; Smith, Justine R.

    2012-01-01

    Retinal endothelial cells line the arborizing microvasculature that supplies and drains the neural retina. The anatomical and physiological characteristics of these endothelial cells are consistent with nutritional requirements and protection of a tissue critical to vision. On the one hand, the endothelium must ensure the supply of oxygen and other nutrients to the metabolically active retina, and allow access to circulating cells that maintain the vasculature or survey the retina for the presence of potential pathogens. On the other hand, the endothelium contributes to the blood-retinal barrier that protects the retina by excluding circulating molecular toxins, microorganisms, and pro-inflammatory leukocytes. Features required to fulfill these functions may also predispose to disease processes, such as retinal vascular leakage and neovascularization, and trafficking of microbes and inflammatory cells. Thus, the retinal endothelial cell is a key participant in retinal ischemic vasculopathies that include diabetic retinopathy and retinopathy of prematurity, and retinal inflammation or infection, as occurs in posterior uveitis. Using gene expression and proteomic profiling, it has been possible to explore the molecular phenotype of the human retinal endothelial cell and contribute to understanding of the pathogenesis of these diseases. In addition to providing support for the involvement of well-characterized endothelial molecules, profiling has the power to identify new players in retinal pathologies. Findings may have implications for the design of new biological therapies. Additional progress in this field is anticipated as other technologies, including epigenetic profiling methods, whole transcriptome shotgun sequencing, and metabolomics, are used to study the human retinal endothelial cell. PMID:22982179

  9. Endothelial activation by platelets from sickle cell anemia patients.

    PubMed

    Proença-Ferreira, Renata; Brugnerotto, Ana Flávia; Garrido, Vanessa Tonin; Dominical, Venina Marcela; Vital, Daiana Morelli; Ribeiro, Marilene de Fátima Reis; dos Santos, Melissa Ercolin; Traina, Fabíola; Olalla-Saad, Sara T; Costa, Fernando Ferreira; Conran, Nicola

    2014-01-01

    Sickle cell anemia (SCA) is associated with a hypercoagulable state. Increased platelet activation is reported in SCA and SCA platelets may present augmented adhesion to the vascular endothelium, potentially contributing to the vaso-occlusive process. We sought to observe the effects of platelets (PLTs) from healthy control (CON) individuals and SCA individuals on endothelial activation, in vitro. Human umbilical vein endothelial cells (HUVEC) were cultured, in the presence, or not, of washed PLTs from CON or steady-state SCA individuals. Supernatants were reserved for cytokine quantification, and endothelial adhesion molecules (EAM) were analyzed by flow cytometry; gene expressions of ICAM1 and genes of the NF-κB pathway were analyzed by qPCR. SCA PLTs were found to be more inflammatory, displaying increased adhesive properties, an increased production of IL-1β and a tendency towards elevated expressions of P-selectin and activated αIIbβ3. Following culture in the presence of SCA PLTs, HUVEC presented significant augmentations in the expressions of the EAM, ICAM-1 and E-selectin, as well as increased IL-8 production and increased ICAM1 and NFKB1 (encodes p50 subunit of NF-κB) gene expressions. Interestingly, transwell inserts abolished the effects of SCA PLTs on EAM expression. Furthermore, an inhibitor of the NF-κB pathway, BAY 11-7082, also prevented the induction of EAM expression on the HUVEC surface by SCA PLTs. In conclusion, we find further evidence to indicate that platelets circulate in an activated state in sickle cell disease and are capable of stimulating endothelial cell activation. This effect appears to be mediated by direct contact, or even adhesion, between the platelets and endothelial cells and via NFκB-dependent signaling. As such, activated platelets in SCD may contribute to endothelial activation and, therefore, to the vaso-occlusive process. Results provide further evidence to support the use of anti-platelet approaches in association

  10. Antiangiogenic effects of melatonin in endothelial cell cultures.

    PubMed

    Alvarez-García, Virginia; González, Alicia; Alonso-González, Carolina; Martínez-Campa, Carlos; Cos, Samuel

    2013-05-01

    Endothelial cells represent one of the critical cellular elements in tumor microenvironment playing a crucial role in the growth and progression of cancer through controlling angiogenesis. Vascular endothelial growth factor (VEGF) produced from tumor cells is essential for the expansion of breast cancer and may function in both paracrine and autocrine manners to promote proliferation, growth, survival and migration of endothelial cells. Since melatonin regulates tumor microenvironment by decreasing the secretion of VEGF by malignant epithelial cells and also regulates VEGF expression in human breast cancer cells, the aim of the present study was to investigate the anti-angiogenic activity of melatonin against the pro-angiogenic effects of breast cancer cells. In this work, we demonstrate that melatonin strongly inhibited the proliferation as well as invasion/migration of human umbilical vein endothelial cells (HUVECs). Melatonin disrupted tube formation and counteracted the VEGF-stimulated tubular network formation by HUVEC. In addition, conditioned media collected from human breast cancer cells were angiogenically active and stimulated tubule length formation and this effect was significantly counteracted by the addition of anti-VEGF or melatonin. Melatonin also disintegrated preformed capillary network. All these findings demonstrate that melatonin may play a role in the paracrine interactions that take place between malignant epithelial cells and proximal endothelial cells. Melatonin could be important in reducing endothelial cell proliferation, invasion, migration and tube formation, through a downregulatory action on VEGF. Taken together, our findings suggest that melatonin could potentially be beneficial as an antiangiogenic agent in breast cancer with possible future clinical applications. PMID:23473980

  11. Extrarenal Progenitor Cells Do Not Contribute to Renal Endothelial Repair.

    PubMed

    Sradnick, Jan; Rong, Song; Luedemann, Anika; Parmentier, Simon P; Bartaun, Christoph; Todorov, Vladimir T; Gueler, Faikah; Hugo, Christian P; Hohenstein, Bernd

    2016-06-01

    Endothelial progenitor cells (EPCs) may be relevant contributors to endothelial cell (EC) repair in various organ systems. In this study, we investigated the potential role of EPCs in renal EC repair. We analyzed the major EPC subtypes in murine kidneys, blood, and spleens after induction of selective EC injury using the concanavalin A/anti-concanavalin A model and after ischemia/reperfusion (I/R) injury as well as the potential of extrarenal cells to substitute for injured local EC. Bone marrow transplantation (BMTx), kidney transplantation, or a combination of both were performed before EC injury to allow distinction of extrarenal or BM-derived cells from intrinsic renal cells. During endothelial regeneration, cells expressing markers of endothelial colony-forming cells (ECFCs) were the most abundant EPC subtype in kidneys, but were not detected in blood or spleen. Few cells expressing markers of EC colony-forming units (EC-CFUs) were detected. In BM chimeric mice (C57BL/6 with tandem dimer Tomato-positive [tdT+] BM cells), circulating and splenic EC-CFUs were BM-derived (tdT+), whereas cells positive for ECFC markers in kidneys were not. Indeed, most BM-derived tdT+ cells in injured kidneys were inflammatory cells. Kidneys from C57BL/6 donors transplanted into tdT+ recipients with or without prior BMTx from C57BL/6 mice were negative for BM-derived or extrarenal ECFCs. Overall, extrarenal cells did not substitute for any intrinsic ECs. These results demonstrate that endothelial repair in mouse kidneys with acute endothelial lesions depends exclusively on local mechanisms.

  12. Von Willebrand factor regulates complement on endothelial cells.

    PubMed

    Noone, Damien G; Riedl, Magdalena; Pluthero, Fred G; Bowman, Mackenzie L; Liszewski, M Kathryn; Lu, Lily; Quan, Yi; Balgobin, Steve; Schneppenheim, Reinhard; Schneppenheim, Sonja; Budde, Ulrich; James, Paula; Atkinson, John P; Palaniyar, Nades; Kahr, Walter H A; Licht, Christoph

    2016-07-01

    Atypical hemolytic uremic syndrome and thrombotic thrombocytopenic purpura have traditionally been considered separate entities. Defects in the regulation of the complement alternative pathway occur in atypical hemolytic uremic syndrome, and defects in the cleavage of von Willebrand factor (VWF)-multimers arise in thrombotic thrombocytopenic purpura. However, recent studies suggest that both entities are related as defects in the disease-causing pathways overlap or show functional interactions. Here we investigate the possible functional link of VWF-multimers and the complement system on endothelial cells. Blood outgrowth endothelial cells (BOECs) were obtained from 3 healthy individuals and 2 patients with Type 3 von Willebrand disease lacking VWF. Cells were exposed to a standardized complement challenge via the combination of classical and alternative pathway activation and 50% normal human serum resulting in complement fixation to the endothelial surface. Under these conditions we found the expected release of VWF-multimers causing platelet adhesion onto BOECs from healthy individuals. Importantly, in BOECs derived from patients with von Willebrand disease complement C3c deposition and cytotoxicity were more pronounced than on BOECs derived from normal individuals. This is of particular importance as primary glomerular endothelial cells display a heterogeneous expression pattern of VWF with overall reduced VWF abundance. Thus, our results support a mechanistic link between VWF-multimers and the complement system. However, our findings also identify VWF as a new complement regulator on vascular endothelial cells and suggest that VWF has a protective effect on endothelial cells and complement-mediated injury. PMID:27236750

  13. Involvement of Local Lamellipodia in Endothelial Barrier Function

    PubMed Central

    Breslin, Jerome W.; Zhang, Xun E.; Worthylake, Rebecca A.; Souza-Smith, Flavia M.

    2015-01-01

    Recently we observed that endothelial cells cultured in tightly confluent monolayers display frequent local lamellipodia, and that thrombin, an agent that increases endothelial permeability, reduces lamellipodia protrusions. This led us to test the hypothesis that local lamellipodia contribute to endothelial barrier function. Movements of subcellular structures containing GFP-actin or VE-cadherin-GFP expressed in endothelial cells were recorded using time-lapse microscopy. Transendothelial electrical resistance (TER) served as an index of endothelial barrier function. Changes in both lamellipodia dynamics and TER were assessed during baseline and after cells were treated with either the barrier-disrupting agent thrombin, or the barrier-stabilizing agent sphingosine-1-phosphate (S1P). The myosin II inhibitor blebbistatin was used to selectively block lamellipodia formation, and was used to test their role in the barrier function of endothelial cell monolayers and isolated, perfused rat mesenteric venules. Myosin light chain (MLC) phosphorylation was assessed by immunofluorescence microscopy. Rac1 and RhoA activation were evaluated using G-LISA assays. The role of Rac1 was tested with the specific inhibitor NSC23766 or by expressing wild-type or dominant negative GFP-Rac1. The results show that thrombin rapidly decreased both TER and the lamellipodia protrusion frequency. S1P rapidly increased TER in association with increased protrusion frequency. Blebbistatin nearly abolished local lamellipodia protrusions while cortical actin fibers and stress fibers remained intact. Blebbistatin also significantly decreased TER of cultured endothelial cells and increased permeability of isolated rat mesenteric venules. Both thrombin and S1P increased MLC phosphorylation and activation of RhoA. However, thrombin and S1P had differential impacts on Rac1, correlating with the changes in TER and lamellipodia protrusion frequency. Overexpression of Rac1 elevated, while NSC23766 and

  14. Involvement of local lamellipodia in endothelial barrier function.

    PubMed

    Breslin, Jerome W; Zhang, Xun E; Worthylake, Rebecca A; Souza-Smith, Flavia M

    2015-01-01

    Recently we observed that endothelial cells cultured in tightly confluent monolayers display frequent local lamellipodia, and that thrombin, an agent that increases endothelial permeability, reduces lamellipodia protrusions. This led us to test the hypothesis that local lamellipodia contribute to endothelial barrier function. Movements of subcellular structures containing GFP-actin or VE-cadherin-GFP expressed in endothelial cells were recorded using time-lapse microscopy. Transendothelial electrical resistance (TER) served as an index of endothelial barrier function. Changes in both lamellipodia dynamics and TER were assessed during baseline and after cells were treated with either the barrier-disrupting agent thrombin, or the barrier-stabilizing agent sphingosine-1-phosphate (S1P). The myosin II inhibitor blebbistatin was used to selectively block lamellipodia formation, and was used to test their role in the barrier function of endothelial cell monolayers and isolated, perfused rat mesenteric venules. Myosin light chain (MLC) phosphorylation was assessed by immunofluorescence microscopy. Rac1 and RhoA activation were evaluated using G-LISA assays. The role of Rac1 was tested with the specific inhibitor NSC23766 or by expressing wild-type or dominant negative GFP-Rac1. The results show that thrombin rapidly decreased both TER and the lamellipodia protrusion frequency. S1P rapidly increased TER in association with increased protrusion frequency. Blebbistatin nearly abolished local lamellipodia protrusions while cortical actin fibers and stress fibers remained intact. Blebbistatin also significantly decreased TER of cultured endothelial cells and increased permeability of isolated rat mesenteric venules. Both thrombin and S1P increased MLC phosphorylation and activation of RhoA. However, thrombin and S1P had differential impacts on Rac1, correlating with the changes in TER and lamellipodia protrusion frequency. Overexpression of Rac1 elevated, while NSC23766 and

  15. Raman microscopy as a novel tool to detect endothelial dysfunction.

    PubMed

    Baranska, Malgorzata; Kaczor, Agnieszka; Malek, Kamilla; Jaworska, Aleksandra; Majzner, Katarzyna; Staniszewska-Slezak, Emilia; Pacia, Marta Z; Zajac, Grzegorz; Dybas, Jakub; Wiercigroch, Ewelina

    2015-08-01

    Raman microscopy, a label-free method with high spatial resolution, shows growing potential in various fields of medical diagnostics. Several proof-of-concept studies related to the application of Raman microscopy to detect endothelial dysfunction are summarized in this work. Both ex vivo measurements of the tissues in the murine models of endothelial pathologies, as well as in vitro investigations of the cell cultures in the context of cellular transport, drug action and inflammation processes are discussed. The future directions in application of Raman spectroscopy-based methods in such studies are also described. PMID:26321275

  16. Human Endothelial Cells: Use of Heparin in Cloning and Long-Term Serial Cultivation

    NASA Astrophysics Data System (ADS)

    Thornton, Susan C.; Mueller, Stephen N.; Levine, Elliot M.

    1983-11-01

    Endothelial cells from human blood vessels were cultured in vitro, with doubling times of 17 to 21 hours for 42 to 79 population doublings. Cloned human endothelial cell strains were established for the first time and had similar proliferative capacities. This vigorous cell growth was achieved by addition of heparin to culture medium containing reduced concentrations of endothelial cell growth factor. The routine cloning and long-term culture of human endothelial cells will facilitate studying the human endothelium in vitro.

  17. Hydrogen-Rich Medium Attenuated Lipopolysaccharide-Induced Monocyte-Endothelial Cell Adhesion and Vascular Endothelial Permeability via Rho-Associated Coiled-Coil Protein Kinase.

    PubMed

    Xie, Keliang; Wang, Weina; Chen, Hongguang; Han, Huanzhi; Liu, Daquan; Wang, Guolin; Yu, Yonghao

    2015-07-01

    Sepsis is the leading cause of death in critically ill patients. In recent years, molecular hydrogen, as an effective free radical scavenger, has been shown a selective antioxidant and anti-inflammatory effect, and it is beneficial in the treatment of sepsis. Rho-associated coiled-coil protein kinase (ROCK) participates in junction between normal cells, and regulates vascular endothelial permeability. In this study, we used lipopolysaccharide to stimulate vascular endothelial cells and explored the effects of hydrogen-rich medium on the regulation of adhesion of monocytes to endothelial cells and vascular endothelial permeability. We found that hydrogen-rich medium could inhibit adhesion of monocytes to endothelial cells and decrease levels of adhesion molecules, whereas the levels of transepithelial/endothelial electrical resistance values and the expression of vascular endothelial cadherin were increased after hydrogen-rich medium treatment. Moreover, hydrogen-rich medium could lessen the expression of ROCK, as a similar effect of its inhibitor Y-27632. In addition, hydrogen-rich medium could also inhibit adhesion of polymorphonuclear neutrophils to endothelial cells. In conclusion, hydrogen-rich medium could regulate adhesion of monocytes/polymorphonuclear neutrophils to endothelial cells and vascular endothelial permeability, and this effect might be related to the decreased expression of ROCK protein.

  18. Epoxyeicosatrienoic Acids and 20-Hydroxyeicosatetraenoic Acid on Endothelial and Vascular Function.

    PubMed

    Imig, J D

    2016-01-01

    Endothelial and vascular smooth cells generate cytochrome P450 (CYP) arachidonic acid metabolites that can impact endothelial cell function and vascular homeostasis. The objective of this review is to focus on the physiology and pharmacology of endothelial CYP metabolites. The CYP pathway produces two types of eicosanoid products: epoxyeicosatrienoic acids (EETs), formed by CYP epoxygenases, and hydroxyeicosatetraenoic acids (HETEs), formed by CYP hydroxylases. Advances in CYP enzymes, EETs, and 20-HETE by pharmacological and genetic means have led to a more complete understanding of how these eicosanoids impact on endothelial cell function. Endothelial-derived EETs were initially described as endothelial-derived hyperpolarizing factors. It is now well recognized that EETs importantly contribute to numerous endothelial cell functions. On the other hand, 20-HETE is the predominant CYP hydroxylase synthesized by vascular smooth muscle cells. Like EETs, 20-HETE acts on endothelial cells and impacts importantly on endothelial and vascular function. An important aspect for EETs and 20-HETE endothelial actions is their interactions with hormonal and paracrine factors. These include interactions with the renin-angiotensin system, adrenergic system, puringeric system, and endothelin. Alterations in CYP enzymes, 20-HETE, or EETs contribute to endothelial dysfunction and cardiovascular diseases such as ischemic injury, hypertension, and atherosclerosis. Recent advances have led to the development of potential therapeutics that target CYP enzymes, 20-HETE, or EETs. Thus, future investigation is required to obtain a more complete understanding of how CYP enzymes, 20-HETE, and EETs regulate endothelial cell function.

  19. Scleroderma fibroblasts show increased responsiveness to endothelial cell-derived IL-1 and bFGF.

    PubMed

    Denton, C P; Xu, S; Black, C M; Pearson, J D

    1997-03-01

    Fibroblasts cultured from lesional skin in scleroderma (systemic sclerosis) demonstrate an activated phenotype that may be important in pathogenesis. Endothelial cell-derived cytokines can modulate fibroblast properties, and endothelial cell changes occur early in scleroderma. Thus, endothelial cell and fibroblast dysfunction may be linked through the paracrine activity of soluble endothelial cell products. We have explored endothelial cell-fibroblast interactions in vitro by investigating the modulation of scleroderma and control fibroblast properties by endothelial cell-conditioned medium (EC-CM). EC-CM caused a concentration-dependent stimulation of fibroblast DNA and protein synthesis and upregulation of cell surface ICAM-1 expression. Scleroderma fibroblasts showed consistently greater responses than control cells. Medium conditioned by mechanically wounded endothelial cells had a greater effect than that from resting endothelial cells. Pre-incubation of EC-CM with anti-bFGF significantly reduced the promotion of fibroblast thymidine incorporation but did not affect endothelial cell-induced leucine incorporation. Conversely, anti-IL-1 antibodies abrogated EC-CM-induced leucine incorporation and ICAM-1 expression but did not diminish thymidine incorporation. Recombinant bFGF or IL-1 modulated fibroblast properties similarly. These data demonstrate that endothelial cell-derived IL-1 and bFGF modulate fibroblast properties independently and that lesional scleroderma strains are more responsive than control fibroblasts to endothelial cell-induced modulation, which supports the hypothesis that altered endothelial cell-fibroblast communication may be involved in the pathogenesis of scleroderma.

  20. Augmentation of platelet and endothelial cell eNOS activity decreases sepsis-related neutrophil-endothelial cell interactions.

    PubMed

    Khan, Raymond; Kirschenbaum, Linda A; LaRow, Catherine; Berna, Gioiamaria; Griffin, Kelly; Astiz, Mark E

    2010-03-01

    NO is an important mediator of microvascular patency and blood flow. The purpose of this study was to examine the role of enhanced eNOS activity in attenuating sepsis-induced neutrophil-endothelial cell interactions. Microslides coated with human umbilical vein endothelial cells were stimulated with plasma from patients with septic shock. Neutrophil and platelets from control subjects were also stimulated with plasma from patients in septic shock and perfused over stimulated endothelial cells. l-Arginine (LA) with and without NG-monomethyl l-arginine (LNMMA), a nonselective NOS inhibitor, and N-(3-(aminomethyl) benzyl acetamide) ethanimidamide dihydrochloride (1400W), a highly selective iNOS inhibitor, were added to the septic plasma. The number of neutrophils adherent to endothelial cells, neutrophil rolling velocity, and the number of neutrophil aggregates were determined. Cell activation and the formation of platelet-neutrophil aggregates were assessed by flow cytometry. Separate experiments were done with isolated platelets using platelet aggregometry. l-Arginine significantly decreased sepsis-related neutrophil adhesion and aggregation and increased rolling velocity. The addition of LNMMA to LA and cell suspensions reversed the effects of LA on these parameters, whereas the addition of 1400W had no effect on LA-related changes. Platelet-neutrophil aggregation, platelet aggregation, platelet activation, and neutrophil activation induced by septic plasma were also significantly decreased by LA. Again, the addition of LNMMA reversed the effects of LA on these parameters, whereas 1400W had no effect on LA-related changes. These data suggest that enhancement of platelet and endothelial cell eNOS activity decreases sepsis-induced neutrophil-endothelial cell interactions and may play a role in maintaining microvascular patency in septic shock.

  1. Endothelial nitric oxide synthase negatively regulates hydrogen peroxide-stimulated AMP-activated protein kinase in endothelial cells.

    PubMed

    Jin, Benjamin Y; Sartoretto, Juliano L; Gladyshev, Vadim N; Michel, Thomas

    2009-10-13

    Hydrogen peroxide and other reactive oxygen species are intimately involved in endothelial cell signaling. In many cell types, the AMP-activated protein kinase (AMPK) has been implicated in the control of metabolic responses, but the role of endothelial cell redox signaling in the modulation of AMPK remains to be completely defined. We used RNA interference and pharmacological methods to establish that H(2)O(2) is a critical activator of AMPK in cultured bovine aortic endothelial cells (BAECs). H(2)O(2) treatment of BAECs rapidly and significantly increases the phosphorylation of AMPK. The EC(50) for H(2)O(2)-promoted phosphorylation of AMPK is 65 + or - 15 microM, within the physiological range of cellular H(2)O(2) concentrations. The Ca(2+)/calmodulin-dependent protein kinase kinase-beta (CaMKKbeta) inhibitor STO-609 abolishes H(2)O(2)-dependent AMPK activation, whereas eNOS inhibitors enhance AMPK activation. Similarly, siRNA-mediated knockdown of CaMKKbeta abrogates AMPK activation, whereas siRNA-mediated knockdown of eNOS leads to a striking increase in AMPK phosphorylation. Cellular imaging studies using the H(2)O(2) biosensor HyPer show that siRNA-mediated eNOS knockdown leads to a marked increase in intracellular H(2)O(2) generation, which is blocked by PEG-catalase. eNOS(-/-) mice show a marked increase in AMPK phosphorylation in liver and lung compared to wild-type mice. Lung endothelial cells from eNOS(-/-) mice also show a significant increase in AMPK phosphorylation. Taken together, these results establish that CaMKKbeta is critically involved in mediating the phosphorylation of AMPK promoted by H(2)O(2) in endothelial cells, and document that eNOS is an important negative regulator of AMPK phosphorylation and intracellular H(2)O(2) generation in endothelial cells. PMID:19805165

  2. Featured Article: Differential regulation of endothelial nitric oxide synthase phosphorylation by protease-activated receptors in adult human endothelial cells

    PubMed Central

    Tillery, Lakeisha C; Epperson, Tenille A; Eguchi, Satoru

    2016-01-01

    Protease-activated receptors have been shown to regulate endothelial nitric oxide synthase through the phosphorylation of specific sites on the enzyme. It has been established that PAR-2 activation phosphorylates eNOS-Ser-1177 and leads to the production of the potent vasodilator nitric oxide, while PAR-1 activation phosphorylates eNOS-Thr-495 and decreases nitric oxide production in human umbilical vein endothelial cells. In this study, we hypothesize a differential coupling of protease-activated receptors to the signaling pathways that regulates endothelial nitric oxide synthase and nitric oxide production in primary adult human coronary artery endothelial cells. Using Western Blot analysis, we showed that thrombin and the PAR-1 activating peptide, TFLLR, lead to the phosphorylation of eNOS-Ser-1177 in human coronary artery endothelial cells, which was blocked by SCH-79797 (SCH), a PAR-1 inhibitor. Using the nitrate/nitrite assay, we also demonstrated that the thrombin- and TFLLR-induced production of nitric oxide was inhibited by SCH and L-NAME, a NOS inhibitor. In addition, we observed that TFLLR, unlike thrombin, significantly phosphorylated eNOS-Thr-495, which may explain the observed delay in nitric oxide production in comparison to that of thrombin. Activation of PAR-2 by SLIGRL, a PAR-2 specific ligand, leads to dual phosphorylation of both catalytic sites but primarily regulated eNOS-Thr-495 phosphorylation with no change in nitric oxide production in human coronary artery endothelial cells. PAR-3, known as the non-signaling receptor, was activated by TFRGAP, a PAR-3 mimicking peptide, and significantly induced the phosphorylation of eNOS-Thr-495 with minimal phosphorylation of eNOS-Ser-1177 with no change in nitric oxide production. In addition, we confirmed that PAR-mediated eNOS-Ser-1177 phosphorylation was Ca2+-dependent using the Ca2+ chelator, BAPTA, while eNOS-Thr-495 phosphorylation was mediated via Rho kinase using the ROCK inhibitor, Y-27632

  3. Featured Article: Differential regulation of endothelial nitric oxide synthase phosphorylation by protease-activated receptors in adult human endothelial cells.

    PubMed

    Tillery, Lakeisha C; Epperson, Tenille A; Eguchi, Satoru; Motley, Evangeline D

    2016-03-01

    Protease-activated receptors have been shown to regulate endothelial nitric oxide synthase through the phosphorylation of specific sites on the enzyme. It has been established that PAR-2 activation phosphorylates eNOS-Ser-1177 and leads to the production of the potent vasodilator nitric oxide, while PAR-1 activation phosphorylates eNOS-Thr-495 and decreases nitric oxide production in human umbilical vein endothelial cells. In this study, we hypothesize a differential coupling of protease-activated receptors to the signaling pathways that regulates endothelial nitric oxide synthase and nitric oxide production in primary adult human coronary artery endothelial cells. Using Western Blot analysis, we showed that thrombin and the PAR-1 activating peptide, TFLLR, lead to the phosphorylation of eNOS-Ser-1177 in human coronary artery endothelial cells, which was blocked by SCH-79797 (SCH), a PAR-1 inhibitor. Using the nitrate/nitrite assay, we also demonstrated that the thrombin- and TFLLR-induced production of nitric oxide was inhibited by SCH and L-NAME, a NOS inhibitor. In addition, we observed that TFLLR, unlike thrombin, significantly phosphorylated eNOS-Thr-495, which may explain the observed delay in nitric oxide production in comparison to that of thrombin. Activation of PAR-2 by SLIGRL, a PAR-2 specific ligand, leads to dual phosphorylation of both catalytic sites but primarily regulated eNOS-Thr-495 phosphorylation with no change in nitric oxide production in human coronary artery endothelial cells. PAR-3, known as the non-signaling receptor, was activated by TFRGAP, a PAR-3 mimicking peptide, and significantly induced the phosphorylation of eNOS-Thr-495 with minimal phosphorylation of eNOS-Ser-1177 with no change in nitric oxide production. In addition, we confirmed that PAR-mediated eNOS-Ser-1177 phosphorylation was Ca(2+)-dependent using the Ca(2+) chelator, BAPTA, while eNOS-Thr-495 phosphorylation was mediated via Rho kinase using the ROCK inhibitor, Y-27632

  4. Internalization of Aspergillus fumigatus conidia by epithelial and endothelial cells.

    PubMed Central

    Paris, S; Boisvieux-Ulrich, E; Crestani, B; Houcine, O; Taramelli, D; Lombardi, L; Latgé, J P

    1997-01-01

    The internalization of conidia of the opportunistic fungus Aspergillus fumigatus by primary cell cultures of nonprofessional phagocytes was investigated. This study is the first to show that A. fumigatus conidia were able to be engulfed by tracheal epithelial, alveolar type II, and endothelial cells. PMID:9119494

  5. Angiotensin-converting enzyme kinetics in an endothelial cell column

    SciTech Connect

    Howell, R.E.; Haselton, F.R.; Mueller, S.N. )

    1990-04-01

    The kinetics of saturable endothelial metabolic functions have been assessed in vivo by transient (indicator-dilution) measurements and in culture by steady-state measurements, but comparisons between the two are difficult. Therefore, we used indicator-dilution methods to assess the kinetics of angiotensin-converting enzyme (ACE) activity in cultured endothelium. Bovine fetal aortic endothelial cells were grown to confluence on microcarrier beads. Cell-covered beads were poured into polypropylene columns and perfused with serum-free culture medium. Six injections, containing (3H)benzol-Phe-Ala-Pro (( 3H)BPAP, an ACE substrate) and varying amounts of unlabeled BPAP, were applied to each column and effluent was collected in serial samples. The apparent kinetics of BPAP metabolism were determined by four models used previously to determine pulmonary endothelial ACE kinetics in vivo, the most useful model incorporating transit time heterogeneity. The Km averaged 5 microM, which is close to values determined previously in vivo and in vitro. The Amax (Vmax.reaction volume) and Amax/Km averaged 6 nmol/min and 1.5 ml/min, respectively, which are lower than estimates in vivo. In conclusion, we have developed a new method for investigating saturable metabolic activity in cultured endothelium, which after further exploration should also enable better comparisons of endothelial metabolic functions in vivo and in culture.

  6. Zinc and dexamethasone induce metallothionein accumulation by endothelial cells

    SciTech Connect

    Briske-Anderson, M.; Bobilya, D.J.; Reeves, P.G. )

    1991-03-11

    Several tissues increase their metallothionein (MT) concentration when exposed to elevated amounts of plasma Zn. Endothelial cells form the blood vessels that supply all tissues and constitute a barrier between cells of tissues and the blood. This study examined the ability of endothelia