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Histamine causes endothelial barrier disruption via Ca 2+ ‐mediated RhoA activation and enhanced force generation at intercellular junctions
Author(s) -
Rotkopf Lukas,
Kugelmann Daniela,
Walter Elias,
Radeva Mariya,
Waschke Jens
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.978.1
Subject(s) - rhoa , adherens junction , histamine , tight junction , chemistry , cell junction , rock1 , microbiology and biotechnology , biophysics , signal transduction , biochemistry , pharmacology , biology , cadherin , cell
During inflammation, disruption of endothelial adherens junctions (AJ) and tight junctions (TJ) leads to increased microvascular permeability. In this study we used histamine to induce acute endothelial barrier breakdown in primary human microvascular endothelial cells. Using FURA‐2AM we observed a rapid Ca 2+ influx induced by both histamine and thrombin accompanied by reduced transendothelial electric resistance (TER). Breakdown coincided with increased stress fiber and focal adhesion formation. The histamine response was blocked by the histamine receptor type 1 antagonist (H1R) diphenhydramine but not by the H2R antagonist ranitidine. Interestingly, GLISA measurements revealed activation of RhoA but not inactivation of Rac1 at the time‐point of barrier breakdown. FRET measurements showed activation of RhoA at intercellular junctions after both thrombin and histamine exposure. At the same time course we observed increased tension at AJs indicated by immunostaining with a conformation‐sensitive antibody targeting the α18‐subunit of α‐catenin. Both Ca 2+ chelation by BAPTA‐AM and inhibition of ROCK1 abolished increased tension along AJs and barrier dysfunction in TER. Since BAPTA‐AM decreased RhoA activation following histamine stimulation, the data suggest a key role of Ca 2+ signaling in barrier breakdown. Our data suggest that the patterns of signaling mechanisms engaged in acute inflammatory barrier disruption differ to more delayed responses as seen in sepsis. In response to histamine, Ca 2+ via RhoA/ROCK activation leading to increased tension along junctions appears to be critical for barrier disruption.