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Oxidative stress disrupts nitric oxide synthase activation in liver endothelial cells.
- Source :
-
Free radical biology & medicine [Free Radic Biol Med] 2005 Nov 15; Vol. 39 (10), pp. 1320-31. Date of Electronic Publication: 2005 Aug 10. - Publication Year :
- 2005
-
Abstract
- Oxidative stress may mediate vascular disruption associated with a loss of endothelial nitric oxide synthase (eNOS) activity and a hypersensitivity to the constrictor effects of endothelin-1 (ET-1). We hypothesize that this is due, in part, to uncoupling of ET(B) receptors from eNOS activation. Thus, we tested whether oxidative stress (OS) affects liver vascular relaxation by reducing basal and ET-1-induced NO production. Primary sinusoidal endothelial cell cultures were pretreated with H(2)O(2) (25 microM) for 1 or 6 h before a 10-min ET-1 stimulation. OS resulted in a significant basal and ET-1-induced decrease in NO production. Acute OS increased the monomeric form of the inhibitory protein caveolin-1 (1.2 +/- 0.05 vs 0.9 +/- 0.02, p < 0.01) and increased the eNOS-caveolin association as determined by coimmunoprecipitation (1.24 +/- 0.04 vs 0.97 +/- 0.04, p < 0.05). ET-1 stimulation further exacerbated these effects. Subacute OS inhibited ET-1-induced eNOS phosphorylation of serine 1177 (activation residue) (1 +/- 0.07 vs 1.6 +/- 0.04, p < 0.05) and dephosphorylation of the inhibitory residue threonine 495 (1.5 +/- 0.08 vs 0.7 +/- 0.02, p < 0.01). Additionally subacute OS resulted in dissociation of eNOS from ET(B) (0.8 +/- 0.09 vs 1.2 +/- 0.06, p < 0.05). Our findings indicate that acute and subacute oxidative stress result in the inhibition of induced nitric oxide synthase activity through distinct mechanisms dependent on caveolin-1 inhibition, ET(B) dissociation, and eNOS phosphorylation.
- Subjects :
- Animals
Blotting, Western
Caveolins metabolism
Cell Survival
Dose-Response Relationship, Drug
Endothelial Cells cytology
Endothelin-1 metabolism
Enzyme Activation
Free Radicals
Hydrogen Peroxide pharmacology
Immunoprecipitation
Liver metabolism
Male
Models, Biological
Nitric Oxide metabolism
Nitric Oxide Synthase Type III metabolism
Phosphorylation
RNA metabolism
Rats
Rats, Sprague-Dawley
Reverse Transcriptase Polymerase Chain Reaction
Signal Transduction
Threonine chemistry
Time Factors
Endothelium, Vascular cytology
Liver cytology
Nitric Oxide Synthase metabolism
Oxidative Stress
Subjects
Details
- Language :
- English
- ISSN :
- 0891-5849
- Volume :
- 39
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Free radical biology & medicine
- Publication Type :
- Academic Journal
- Accession number :
- 16257641
- Full Text :
- https://doi.org/10.1016/j.freeradbiomed.2005.06.014