Study of the level of ERM proteins in pulmonary microvascular endothelial cells induced by tumor necrosis factor-α / 中华急诊医学杂志

ABSTRACT

Objective To investigate the effect of tumor necrosis factor-α (TNF-α) on the levels of ezrin-radixin-moesin (ERM) proteins and the phosphorylated ERM proteins (p-ERM) in rat pulmonary microvascular endothelial cells (PMVEC),and to explore Rho kinase (ROCK) influencing on modulation of the ERM proteins phosphorylation.Methods Cultured rat pulmonary microvascular endothelial cells were randomly divided into dose-dependent and time-dependent groups.In dose-dependent group,cells were cultured with different doses of TNF-α (0,0.1,1,10 μg/LTNF-α) for 60 min.In time-dependent group,cells were cultured with TNF-α (10 μg/L) for 0,15,30,60,90,120,180 min.In ROCK inhibitor (Y27632) intervention group,cells were cultured with TNF-α (10 μg/L) or Y27632 (30 μmol/L) + TNF-α (10 μg/L) for 60 min respectively.The levels of ERM proteins and p-ERM were determined by western blot.One way analysis of variance (ANOVA) was employed for statistical analysis by using SPSS version 16.0 software to compare values among all groups.A significant difference was presumed as a P value ＜ 0.05.Results Western blot revealed that ERM and p -ERM proteins were present in rat PMVEC.Stimulation withTNF-α gradually up-regulated the level of pERM proteins in a dose-dependent manner [0 μg/LTNF-α group(0.648 ± 0.102),0.1 μg/LTNF-αgroup(0.728-±0.082),1 μg/LTNF-α group(0.926±0.121),10 μg/LTNF-α group(1.245 ±0.134),all P =0.000].In time-dependent group,the level of p-ERM proteins rose at 15 min (0.777 ±0.151),peaked at 90 min (1.295 ±0.176),then decreased gradually at 120 min (0.802 ±0.139),but stayed higher level at 180 min (0.669 ±0.128) than that in un-stimulated 0 min group (0.631 ±0.123,P=0.004,0.000,0.001,0.016,respectively).When PMVEC pre-incubated with ROCK inhibitor and TNF-t,the level of p-ERM proteins caused a marked attenuation of TNF-αstimulation [(0.634 ± 0.112) vs.(0.875 ± 0.164),P =0.002],however,there are no significant differences compared to ROCK inhibitor alone group (0.661 ± 0.108) and no intervention group (0.654 ± 0.125),P =0.973,P =0.900,respectively).Conclusions TNF-α could induce up-regulation of the level of the phosphorylated ERM proteins in rat PMVEC,and ROCK signal molecules might involve in modulation of the ERM proteins phosphorylation.