RhoA/mDia1 pathway involved in the expression of p-ERM in the pulmonary micro-vascular endothelial cell induced by lipopolysaccharide / 中华急诊医学杂志

Objective To investigate the possibility of the involvement of RhoA/mDia1 pathway to cause the expression of phosphorylate ezrin-radixin-moesin (p-ERM) in rat pulmonary micro-vascular endothelial cell (PMVEC) after the stimulation of lipopolysaccharide (LPS).Methods The specimens of lung tissue were taken from healthy male SPF grade SD rat with 100-120 g body weight which was purchased from the laboratory animal center of Anhui province.After culture,the PMVECs were randomly divided into dose-dependent groups (0,0.1,1,10 μg/mL LPS added in PMVECs and cultured for30 min,n =8 in each),time-dependent groups (10 μg/mL LPS added to PMVECs cultured for 0,15,30,60,120 min,n =8 in each) and intervention group (n =8).In the intervention group,PMVECs were cultured with 1 μg/mL C3 transferase in serum free media for 240 min,followed by treatment with 10 μg/mL LPS for 30 min.Meanwhile,two control groups in serum-free DMEM medium were made by adding 10.μg/mL LPS to PMVECs and 1 μg/mL C3 transferase to PMVECs respectively cultured for 30 min (n =8 in each).Western blot was used to detect the level of p-ERM,ERM and mDia1.Data were analyzed with SPSS 16.0 software,while one way analysis of variance (ANOVA) was used to compare multiple sets of variables,the intergroup comparisons were analyzed by the least-significant-difference (LSD) tests,with P ＜0.05 for the statistically significant difference.Results ERM,p-ERM and mDia1 were presented in rat PMVEC.Stimulation with LPS up-regulated p-ERM,mDia1 in a dose-dependent manner:LPS [0 μg/mL LPS group:(0.520±0.101),0.1 μg/mL LPS group:(0.657 ±0.092),1 μg/mL LPS group:(0.891 ±0.167),10 μg/mL LPS group:(1.227 ±0.106);0 μg/mL group vs.0.1 μg/mL group,P ＞0.05;the rest P ＜0.01];and mDia1 [0 μg/mL LPS group:(0.200 ±0.102),0.1 μg/mL LPS group:(0.430 ±0.121),1 μg/mL LPS group:(0.603 ±0.154),10 μg/mL LPS group:(0.887 ±0.204);0.1 μg/mL group vs.1 μg/mL group,P ＞ 0.05;the rest P ＜ 0.05].In time-dependent group,the level of p-ERM protein increased at 15 min (0.670 ±0.149),peaked at 30 min (1.175 ±0.103),then decreased,at 60 min (0.959 ±0.189),90 min (0.842 ±0.129),but kept at higher level at 120 min (0.767 ±0.097) than that in control group (0.471 ±0.157,15 min group vs.120 min group,60 min group vs.90 min group and 90 min group vs.120 min group,P ＞ 0.05;the rest P ＜ 0.05);and the level of mDia1 increased at 15 min (0.779 ±0.035),peaked at 30 min (0.889 ±0.036) then decreased at 60 min (0.648 ±0.019),90 min (0.582 ±0.068),but kept at higher level at 120 min (0.526 ±0.059) than that in control group (0.284±0.118,all P ＜ 0.01).C3 transferase caused a marked attenuation of LPS induced p-ERM expression [control group:(0.339 ± 0.069);C3 + LPS group:(0.438 ± 0.07);C3 control group:(0.352 ± 0.071);LPS control group:(0.634 ± 0.191),C3 + LPS group vs.LPS control group,P =0.01],as the same in mDia1 [control group:(0.449 ±0.122);C3 + LPS group:(0.380 ±0.148);C3 control group:(0.404 ±0.164);LPS control group:(0.622 ±0.174),C3 + LPS group vs.LPS control group,P ＜ 0.01].Conclusions LPS could up-regulated the expression of p-ERM protein,and inhibition of RhoA/mDia1 signal pathway by C3 transferase could down-regulated the p-ERM levels.

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

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.

Amphetamine-induced ERM Proteins Phosphorylation Is through PKCbeta Activation in PC12 Cells

Amphetamine, a synthetic psychostimulant, is transported by the dopamine transporter (DAT) to the cytosol and increases the exchange of extracellular amphetamine by intracellular dopamine. Recently, we reported that the phosphorylation levels of ezrin-radixin-moesin (ERM) proteins are regulated by psychostimulant drugs in the nucleus accumbens, a brain area important for drug addiction. However, the significance of ERM proteins phosphorylation in response to drugs of abuse has not been fully investigated. In this study, using PC12 cells as an in vitro cell model, we showed that amphetamine increases ERM proteins phosphorylation and protein kinase C (PKC) beta inhibitor, but not extracellular signal-regulated kinase (ERK) or phosphatidylinositol 3-kinases (PI3K) inhibitors, abolished this effect. Further, we observed that DAT inhibitor suppressed amphetamine-induced ERM proteins phosphorylation in PC12 cells. These results suggest that PKCbeta-induced DAT regulation may be involved in amphetmaine-induced ERM proteins phosphorylation.

Mechanism of advanced glycation end products-stimulated phosphorylation of ERM protein in human umbilical vein endothelial cells / 中华内分泌代谢杂志

The effects of advanced glycation end products(AGE)on phosphorylation of ezrin/radixin/ moesin(ERM)protein in human umbilical vein endothelial ceils were detected by immunofluorescence cytochemistry and its mechanism was explored.AGE stimulated the phosphorylation of ERM protein in dose-and time-dependent manners(all P<0.05),which was involved in AGE receptor,Rho kinase,and p38 mitogen-activated protein kinase pathways.