Mechanism of HMGB1-induced hyperpermeability in endothelial cells

GUO Xiao-hua; WU Jie; WENG Jie; ZHANG Wei-jin; ZHOU Xiao-yan; WANG Wei-ju; HUANG Qiao-bing; JIANG Yong; XU Jing

Abstract：Objective To investigate the effects of high mobility group protein B1 ( HMGB1) on the permeability of endothelial cells, as well as the roles of receptor for advanced glycation end products ( RAGE) and p38 MAPK pathway in this pathological process.Methods Human umbilical vein endothelium cells ( HUVECs) were incubated with HMGB1 in concentrations of 200 ng/ml for 3、6、12 and 24 h, to detect the time effect of endothelial cell permeability.Pretreated HMVECs with 25 μmol/L p38 MAPK inhibitor SB203580 for 1 h, followed by HMGB1 for another 12 h,compared the change of cell permeability in different groups.Treatment of HUVECs with 200 ng/mL HMGB1 for 0、10、20、30、60 min to observe the time effect of p38 phosphorylation.Treatment with siRNA against RAGE and culturing RAGE knockout pulmo-nary microvascular endothelial cells, to observe the changes of p38 phosphorylation under HMGB1 stimulation.Experi-ments were accomplished by using western blot, endothelial monolayer permeability assay and transendothelial electrical resistance.Results The permeability of endothelial cells and p38 phosphorylation was significantly increased in a time-dependent manner upon the stimulation of HMGB1.The pharmacological inhibition of p38 MAPK kinase greatly attenuated the HMGB1-induced hyperpermeability.Blockade of cell surface receptors RAGE with RAGE siRNA or using RAGE knock out PMVECs significantly reduced HMGB1-induced p38 phosphorylation.Conclusion HMGB1 induces hyper-meability of endothelial cells through binding with RAGE and activating p38 signaling pathway.