Inhibition of the respiratory burst by resveratrol in human monocytes: correlation with inhibition of PI3K signaling.
trans-Resveratrol (t-RVT) has been shown to have a wide range of anti-inflammatory properties, some of which have been suggested to contribute to the molecular explanation of the French Paradox, a possible reason for the low incidence of heart disease in France. The ability of t-RVT to inhibit the production of reactive oxygen species (ROS) from monocytes (differentiated U937) was investigated using isoluminol, luminol, lucigenin, and 2',7'-dichlorofluorescein (DCF). t-RVT (0.1-50 microM) was found to significantly inhibit cellular ROS production stimulated by f-Met-Leu-Phe (fMLP), 12-phorbol 13-myristate, and arachidonic acid after a 1-h preincubation. The efficacy of t-RVT could be increased if it was added directly into the assay. NADPH-dependent superoxide production was measured in cell homogenates and t-RVT (10-50 microM) was found to have no effect on this activity. The majority of these redox probes require a peroxidase to be oxidized; therefore, the inhibitory effect of t-RVT on ROS measured by these probes is complicated by its ability to be oxidized by peroxidase enzymes and thus compete with the probe. t-RVT, known to be oxidized by the horseradish peroxidase (HRP)/H(2)O(2) system, was found to inhibit the HRP-dependent oxidation of the fluorescent probe DCF and the chemiluminescent probe isoluminol. However, using a redox probe that did not require oxidation by a peroxidase (lucigenin), significant inhibition was still observed. Moreover, the inhibitory effects of t-RVT on fMLP-induced ROS production correlated with significant inhibitory effects on fMLP-induced phosphatidylinositol 3-kinase (PI3K) activity at 50 microM and Akt phosphorylation (10-50 microM). Other known inhibitors of both PI3K and Akt were also found to inhibit this response. Therefore, inhibition of signaling through the PI3K to NADPH oxidase by t-RVT might represent an important anti-inflammatory mechanism.
Poolman
Toryn M
TM
Pharmacology and Therapeutics Group, Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Building, Leicester Royal Infirmary, UK. tmp5@le.ac.uk
Ng
Leong L
LL
Farmer
Peter B
PB
Manson
Margaret M
MM
D000166:Acridines / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005456:Fluorescent Dyes / Q000494:pharmacology; D006801:Humans; D009000:Monocytes / Q000187:drug effects* / Q000502:physiology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors; D016897:Respiratory Burst / Q000187:drug effects*; D000077185:Resveratrol; D015398:Signal Transduction / Q000187:drug effects; D013267:Stilbenes / Q000494:pharmacology*; D020298:U937 Cells
D000166:Acridines; D048049:Extracellular Signal-Regulated MAP Kinases; D005456:Fluorescent Dyes; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019255:NADPH Oxidases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D017382:Reactive Oxygen Species; D000077185:Resveratrol; D013267:Stilbenes; C033472:10,10'-dimethyl-9,9'-biacridinium; C494918:AKT1 protein, human