Involvement of p38 MAP kinase, but not ERK‐1/2, in histamine‐induced endothelial actin reorganization and barrier disruption

Abstract

We tested the hypothesis that histamine disrupts the endothelial barrier by activation of the p38 MAP kinase and ERK‐1/2. Transendothelial electrical resistance (TER) of human umbilical vein endothelial cells (HUVEC) grown on small gold electrodes served as an index of barrier function, before and after addition of 10 μM histamine. The role of p38 MAP kinase was tested with 6 μM SB203580 and ERK‐1/2 with 10 μM PD98059 or 1 μM U0126. Specific, dual phosphorylation of p38 MAP kinase or ERK‐1/2 on their activation sites was detected by Western blotting. Dynamics of GFP‐actin and VE‐cadherin‐GFP expressed in HUVEC were also evaluated. The results show that histamine increased phosphorylation of both p38 MAP kinase and ERK‐1/2, which was blocked by pretreatment with SB203580, or PD98059/U0126, respectively. Histamine‐induced decreases in TER were inhibited by SB203580, but not affected by PD98059 or U0126 pretreatment. Histamine did not change VE‐cadherin‐GFP organization, but did briefly stop GFP‐actin‐rich edge protrusions. However, these protrusions were not decreased by histamine when the cells were pretreated with SB203580. The data suggest that p38 MAP kinase, but not ERK‐1/2, mediates histamine‐induced endothelial barrier disruption by reducing endothelial cell spreading motions. Supported by NIH grants R01HL098215 and P20GM103424, NSF grant HRD0928797, and the Louisiana Board of Regents Support Fund.