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Activation of NF-kappaB by palmitate in endothelial cells: a key role for NADPH oxidase-derived superoxide in response to TLR4 activation
- Source :
- Arteriosclerosis, thrombosis, and vascular biology. 29(9)
- Publication Year :
- 2009
-
Abstract
- Objective— We investigated whether NADPH oxidase–dependent production of superoxide contributes to activation of NF-κB in endothelial cells by the saturated free fatty acid palmitate. Methods and Results— After incubation of human endothelial cells with palmitate at a concentration known to induce cellular inflammation (100 μmol/L), we measured superoxide levels by using electron spin resonance spectroscopy and the spin trap 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CMH). Palmitate exposure induced a >2-fold increase in superoxide levels, an effect associated with activation of NF-κB signaling as measured by phospho-IκBα, NF-κB activity, IL-6, and ICAM expression. Reduction in superoxide levels by each of 3 different interventions—pretreatment with superoxide dismutase (SOD), diphenylene iodinium (DPI), or knockdown of NADPH oxidase 4 (NOX4) by siRNA—attenuated palmitate-mediated NF-κB signaling. Inhibition of toll like receptor-4 (TLR4) signaling also suppressed palmitate-mediated superoxide production and associated inflammation, whereas palmitate-mediated superoxide production was not affected by overexpression of a phosphorylation mutant IκBα (NF-κB super repressor) that blocks cellular inflammation downstream of IKKβ/NF-κB. Finally, high-fat feeding increased expression of NOX4 and an upstream activator, bone morphogenic protein (BMP4), in thoracic aortic tissue from C57BL/6 mice, but not in TLR4 −/− mice, compared to low-fat fed controls. Conclusions— These results suggest that NADPH oxidase–dependent superoxide production links palmitate-stimulated TLR4 activation to NF-κB signaling in endothelial cells.
- Subjects :
- Time Factors
Palmitic Acid
Aorta, Thoracic
Bone Morphogenetic Protein 4
chemistry.chemical_compound
Mice
Onium Compounds
NF-KappaB Inhibitor alpha
Superoxides
Phosphorylation
Cells, Cultured
chemistry.chemical_classification
Mice, Knockout
NADPH oxidase
Superoxide
NF-kappa B
NOX4
Intercellular Adhesion Molecule-1
Endothelial stem cell
medicine.anatomical_structure
Interleukin-1 Receptor-Associated Kinases
NADPH Oxidase 4
I-kappa B Proteins
RNA Interference
Cardiology and Cardiovascular Medicine
Signal Transduction
medicine.medical_specialty
Endothelium
Biology
Article
Superoxide dismutase
Internal medicine
medicine
Animals
Humans
RNA, Messenger
Reactive oxygen species
Interleukin-6
Superoxide Dismutase
Endothelial Cells
NADPH Oxidases
Molecular biology
Dietary Fats
Mice, Inbred C57BL
Toll-Like Receptor 4
IκBα
Endocrinology
chemistry
Myeloid Differentiation Factor 88
biology.protein
Subjects
Details
- ISSN :
- 15244636
- Volume :
- 29
- Issue :
- 9
- Database :
- OpenAIRE
- Journal :
- Arteriosclerosis, thrombosis, and vascular biology
- Accession number :
- edsair.doi.dedup.....d2f4927a8c274cb42d6daa24e1a45986