Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
SHR Neuro Krebs Kardio Lipid Stoffw Microb
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.
Doi: 10.1016/j.cardiores.2004.06.026
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- Führende Autor*innen der Med Uni Graz
- Groschner Klaus
- Co-Autor*innen der Med Uni Graz
- Graier Wolfgang
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- Abstract:
- 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
- caveolin
- phospholipase A(2)
- arachidonic acid