Translocation of protein kinase C isoforms is involved in propofol-induced endothelial nitric oxide synthase activation
Background. Previous studies have indicated that protein kinase C (PKC) may enhance endothelial nitric oxide synthase (eNOS) activation, although the detailed mechanism(s) remains unclear. In this study, we investigated the roles of PKC isoforms in regulating propofol-induced eNOS activation in human umbilical vein endothelial cells (HUVECs).Methods. We applied western blot (WB) analysis to investigate the effects of propofol on Ser1177 phosphorylation-dependent eNOS activation in HUVECs. Nitrite (NO 2-) accumulation was measured using the Griess assay. The phosphatidylinositol 3-kinase/Akt (PI3K/Akt) pathway was examined by WB assay. Propofol-induced translocation of individual PKC isoforms in subcellular fractions in HUVECs was analysed using WB assay.Results. In HUVECs, protocol treatment (1-100 μM) for 10 min induced a concentration-dependent increase in phosphorylation of eNOS at Ser1177. The NO production was also increased accordingly. PKC inhibitors, bisindolylmaleimide I (0.1-1 μM), and staurosporine (20 and 100 nM), effectively blocked propofol-induced eNOS activation and NO production. Further analyses in fractionated endothelial lysate showed that short-term propofol treatment (50 μM) led to translocation of PKC-α, PKC-δ, PKC-ζ, PKC-η, and PKC-ε from cytosolic to membrane fractions, which could also be inhibited by both PKC inhibitors. These data revealed that the differential redistribution of these isozymes is ndispensable for propofol-induced eNOS activation. In addition, Akt was not phosphorylated in response to propofol at Ser473 or Thr 308.Conclusions. Propofol induces the Ser1177 phosphorylation-dependent eNOS activation through the drug-stimulated translocation of PKC isoforms to distinct intracellular sites in HUVECs, which is independent of PI3K/Akt-independent pathway. © The Author [2010]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved.
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- Anesthesiology
- 3202 Clinical sciences
- 1103 Clinical Sciences
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Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Anesthesiology
- 3202 Clinical sciences
- 1103 Clinical Sciences