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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 156 (1993), S. 24-34 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have previously shown that supplementing cultured porcine pulmonary artery endothelial cells (PAEC) with exogenous oleic acid (18:1ω9) alters the fatty acid composition of the cells and reduces oxidant-mediated cytotoxicity. Because the mechanisms by which lipid alterations modulate oxidant susceptibility have not been defined, the ability of 18:1 to reduce hydrogen peroxide (H2O2)-mediated PAEC dysfunction was evaluated. PAEC monolayers on polycarbonate filters were incubated for 3 h in maintenance medium supplemented with either 0.1 mM 18.1 in ethanol vehicle (ETOH) or with an equivalent volume of vehicle alone. Twenty-four hours later monolayers were treated for 30 min with 50 or 100 μM H2O2 in Hanks' balanced salt solution (HBSS) or with HBSS alone (nonoxidant control). As a functional index of PAEC monolayer integrity, the permeability of monolayers to albumin was then measured for 3 h. Treatment with 100 μM H2O2 caused cytotoxicity and progressive increases in PAEC monolayer permeability that were attenuated by 18:1 supplementation, whereas 50 μM H2O2 caused only a transient increase in permeability without cytotoxicity. Supplementation with 18:1 also attenuated H2O2-induced reductions in PAEC adenosine triphosphate (ATP) content and disruption of PAEC microfilament architecture. The ATP content of PAEC monolayers was reversibly reduced in the absence of oxidant stress by incubation with glucose-depleted medium containing deoxyglucose and antimycin A. Metabolic inhibitor-induced ATP depletion increased monolayer permeability and altered cytoskeletal architecture, alterations that resolved during recovery of PAEC ATP content. These results demonstrate that ATP depletion plays a critical role in barrier dysfunction and suggests that the ability of 18:1 to reduce oxidant-mediated PAEC dysfunction and injury may relate directly to its ability to preserve PAEC ATP content. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Endothelial cell activation by thrombin is a key event in wound healing, Inflammation, and hemostasis. To better define thrombin-endothelial cell interactions we synthesized several peptides of varying length corresponding to the initial 14 amino acid sequence of the cloned human platelet thrombin receptor after cleavage at an arginine41 site (R/SFLLRNPNDKYEPF). Thrombin receptor activating peptides (TRAPs) as short as 5 amino acids induced significant levels of PGl2 synthesis and expression of PDGF mRNA in human endothelium and produced dose-dependent cellular contraction and permeability of confluent human umbilical vein and bovine pulmonary artery endothelial monolayers. To explore whether TRAPs utilized similar signal transducing pathways as α-thrombin to accomplish endothelial cell activation, phospholipase C production of the Ca2+ secretagogue IP3 was measured and detected 10 seconds after either TRAP 7 or α-thrombin. Furthermore, TRAPs ranging from 5-14 residues induced significant dose-dependent incsreases in Fura-2 fluorescence indicative of Ca2+ 1 mobilization. These results indicate that thrombin-mediated proteolytic cleavage of the human and bovine thrombin receptor initiates stimulus/coupling respones such phospholipase C activation, Ca2+ mobilization, and protein kinase C activation. The functional consequence of this cellular activation via the cleaved receptor is enhanced cellular contraction, barrier dysfunction, PGI2 synthesis, and expression of PDGF mRNA. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Supplemental fatty acids can modify the oxidant susceptibility of pulmonary artery endothelial cells (PAEC) in monolayer culture. In addition, in vivo dietary modifications have altered tissue and animal susceptibility to a variety of forms of oxidant stress. These modifications of oxidant injury have been attributed to changes in the numbers of fatty acid double bonds in cell lipids. We tested this hypothesis by incubating porcine PAEC in culture medium supplemented with either 0.1 mM oieic acid (18: 1ω9) or with an equivalent volume of ethanol vehicle alone (ETOH-0.1%) for 3 h. After supplementation, PAEC were exposed to either oxidant stress, 100 μM hydrogen peroxide (H2O2) in Hanks' balanced salt solution (HBSS), or to control condition, HBSS alone, for 30 min. Supplemented PAEC were exposed to HBSS or H2O2 either immediately or 24, 48, or 72 h after supplementation. Supplementation with 18:1 protected PAEC from H2O2-induced injury at all time points. The fatty acid composition of PAEC phospholipid (PL), triglyceride (TG), and free fatty acid (FFA) subclasses was determined using thin layer and gas chromatography. The PL fraction contained the majority of PAEC fatty acids, and H2O2 reduced the polyunsaturates in this fraction regardless of supplementation. Supplementation with 18:1 increased the 18:1 content of PAEC PL, TG, and FFA at all time points, modified other fatty acids to a lesser extent, but failed to alter the overall number of fatty acid double bonds at all time points. These results indicate that modification of double bond number does not fully explain the mechanisms by which changes in lipid composition can modulate oxidant injury. © 1992 Wiley-Liss, Inc © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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