OBJECTIVETo study the effect of cGMP-dependent protein kinase (PKG) on the pathogenesis of septic shock.

METHODSConfluent endothelial cells were disintegrated and centrifugated to obtain cell lysates after being treated with LPS or PKG activator 8-Br-cGMP. PKG activity of lysates was measured with radioactive isotope label method in a reaction system of phosphorylation of specific substrate H2B by PKG, and the shape and the distribution of intracellular filamentous actin were detected by specific fluorescence staining. For the control study, the PKG specific inhibitor KT5823 was used to pretreat the endothelial cells before the administration of LPS or PKG activator 8-Br-cGMP.

RESULTSExposure to LPS for 5, 10, 30 and 60 minutes led to a rapid time-dependent increase in endothelial PKG activity (P < 0.01 compared to the blank) and the polar distribution of intracellular filamentous actin and preincubation with KT5823 abolished these effects. 8-Br-cGMP was similar to LPS.

CONCLUSIONSThe results suggested that LPS can mediate PKG activation and the stress variety of filamentous actin in the vascular endothelial cells, which probably induce the endothelial hyperpermeability after septic shock.

Capillary Permeability ; Cyclic GMP ; analogs & derivatives ; pharmacology ; Cyclic GMP-Dependent Protein Kinases ; physiology ; Cytoskeleton ; metabolism ; Endothelium, Vascular ; cytology ; metabolism ; Humans ; Lipopolysaccharides ; pharmacology ; Shock, Septic ; metabolism ; Signal Transduction