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Caveolin-1 mediates endotoxin inhibition of endothelin-1-induced endothelial nitric oxide synthase activity in liver sinusoidal endothelial cells.
- Source :
-
American journal of physiology. Gastrointestinal and liver physiology [Am J Physiol Gastrointest Liver Physiol] 2009 Nov; Vol. 297 (5), pp. G930-9. - Publication Year :
- 2009
-
Abstract
- Endothelin-1 (ET-1) plays a key role in the regulation of endothelial nitric oxide synthase (eNOS) activation in liver sinusoidal endothelial cells (LSECs). In the presence of endotoxin, an increase in caveolin-1 (Cav-1) expression impairs ET-1/eNOS signaling; however, the molecular mechanism is unknown. The objective of this study was to investigate the molecular mechanism of Cav-1 in the regulation of LPS suppression of ET-1-mediated eNOS activation in LSECs by examining the effect of caveolae disruption using methyl-beta-cyclodextrin (CD) and filipin. Treatment with 5 mM CD for 30 min increased eNOS activity (+255%, P < 0.05). A dose (0.25 microg/ml) of filipin for 30 min produced a similar effect (+111%, P < 0.05). CD induced the perinuclear localization of Cav-1 and eNOS and stimulated NO production in the same region. Readdition of 0.5 mM cholesterol to saturate CD reversed these effects. Both the combined treatment with CD and ET-1 (CD + ET-1) and with filipin and ET-1 stimulated eNOS activity; however, pretreatment with endotoxin (LPS) abrogated these effects. Following LPS pretreatment, CD + ET-1 failed to stimulate eNOS activity (+51%, P > 0.05), which contributed to the reduced levels of eNOS-Ser1177 phosphorylation and eNOS-Thr495 dephosphorylation, the LPS/CD-induced overexpression and translocation of Cav-1 in the perinuclear region, and the increased perinuclear colocalization of eNOS with Cav-1. These results supported the hypothesis that Cav-1 mediates the action of endotoxin in suppressing ET-1-mediated eNOS activation and demonstrated that the manipulation of caveolae produces significant effects on ET-1-mediated eNOS activity in LSECs.
- Subjects :
- Animals
Anticholesteremic Agents pharmacology
Caveolae drug effects
Cell Membrane metabolism
Cells, Cultured
Cholesterol pharmacology
Cytoplasm metabolism
Endothelial Cells drug effects
Filipin pharmacology
Male
Models, Biological
Nitric Oxide metabolism
Nuclear Envelope metabolism
Phosphorylation drug effects
Protein Binding drug effects
Protein Binding physiology
Protein Transport drug effects
Rats
Rats, Sprague-Dawley
beta-Cyclodextrins pharmacology
Caveolin 1 metabolism
Endothelial Cells metabolism
Endothelin-1 pharmacology
Endotoxins pharmacology
Liver cytology
Nitric Oxide Synthase Type III metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1522-1547
- Volume :
- 297
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Gastrointestinal and liver physiology
- Publication Type :
- Academic Journal
- Accession number :
- 20501440
- Full Text :
- https://doi.org/10.1152/ajpgi.00106.2009