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SHR Neuro Krebs Kardio Lipid

Graziani, A; Bricko, V; Carmignani, M; Graier, WF; Groschner, K.
Cholesterol- and caveolin-rich membrane domains are essential for phospholipase A2-dependent EDHF formation.
CARDIOVASC RES. 2004; 64(2): 234-242. [OPEN ACCESS]
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Autor/innen der Med Uni Graz:
Graier Wolfgang
Groschner Klaus

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Objective: Cholesterol-rich membrane domains, which contain the scaffold protein caveolin-1 (Cav-1) (caveolae), represent an important structural element involved in endothelial signal transduction. The present study was designed to investigate the role of these signaling platforms in the generation of endothelial-derived hyperpolarizing factor (EDHF). Methods: Caveolae were disrupted by cholesterol depletion with methyl-beta-cyclodextrin (MbetaCD 10 mM). MbetaCD-induced modulation of non-nitric oxide-/non-prostanoid-dependent (EDHF)-mediated vasorelaxation was Studied in pig coronary arteries. Effects of MbetaCD on endothelial Ca2+ signaling and phospholipase A(2) (cPLA(2)) activity were determined using fura-2 imaging and measurement of [H-3]-arachidonate mobilization in cultured pig aortic endothelial cells (PAEC). Cellular localization of caveolin-1 and phospholipase A(2) was investigated by cell fractionation, and interaction of cPLA(2) with caveolin-1 was tested by immunoprecipitation experiments. Results: MbetaCD inhibited EDHF-mediated relaxations of pig coronary arteries induced by bradykinin (100 nM) or ionomycin (300 nM) but not relaxations induced by the NO donor DEA/NO (1 muM). Exposure of arteries to cholesterol-saturated MbetaCD failed to affect EDHF-mediated relaxations. Cholesterol depletion with MbetaCD did not affect bradykinin or ionomycin-induced Ca2+ signaling in pig aortic endothelial cells, but was associated with enhanced basal and reduced Ca2+-dependent release of arachidonic acid (AA). Cell fractionation experiments indicated targeting of cPLA(2) to low density, caveolin-1 rich membranes and immunoprecipitation experiments demonstrated association of phospholipase A(2) with the scaffold protein of caveolae, caveolin-1. Cholesterol depletion with MbetaCD did not disrupt the interaction between cPLA(2) and caveolin-1 but prevented targeting of cPLA(2) to low density membranes. Exogenous supplementation of arachidonic acid after cholesterol depletion partially restored EHDF responses in pig coronary arteries. Conclusion: The integrity of caveolin-1-containing membrane microdomains is prerequisite for arachidonic acid recruitment and EDHF signaling in porcine arteries. (C) 2004 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.
Find related publications in this database (using NLM MeSH Indexing)
Animals -
Arachidonic Acid - metabolism Arachidonic Acid - pharmacology
Biological Factors - biosynthesis
Bradykinin - pharmacology
Calcium - metabolism
Calcium Signaling - drug effects
Caveolae - metabolism
Caveolin 1 -
Caveolins - metabolism
Cholesterol - metabolism
Coronary Vessels -
Culture Techniques -
Endothelium, Vascular - metabolism
Enzyme Activation -
Phospholipases A - metabolism
Phospholipases A2 -
Signal Transduction - physiology
Swine -

Find related publications in this database (Keywords)
endothelial-derived hyperpolarizing factor
lipid rafts
phospholipase A(2)
arachidonic acid
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