The mechanism of G-protein-coupled receptor kinase 2 on the pulmonary microvascular endothelial cell injury induced by platelet activating factor

Objective To investigate the mechanism of G protein-coupled receptor kinase(GRK2)on the pulmonary microvascular endothelial cell(PMVEC) injury induced by platelet-activating factor(PAF).Methods PMVEC was isolated and cultured in vitro.The effects of PAF on monolayer permeability of PMVEC was observed with microfilter. F-actin expression of PMVEC was evaluated by flow cytometry.Western blot was also used to measure the expression of GRK2.Results 10mg·L -1 of PAF made the monolayer permeability of PMVEC increase and F-actin depolymerise within 120 min. The expression of GRK2 in PAF group increased significantly compared with normal control group. Phorbol ester inhibited the monolayer permeability to increase and depolymerization of F-actin which was probably mediated by further increased expression of GRK2. Conclusion PAF can induce significant increase in monolayer permeability and expression of GRK2 in PMVEC .The increased monolayer permeability of PMVEC is significantly correlated with the depolymerization of F-actin. These effects of PAF were markedly inhibited by GRK2 over expression induced by phorbol ester, which exerts a protective action on PMVEC injury induced by PAF.