Histamine causes endothelial barrier disruption via Ca2+-mediated RhoA activation and tension at adherens junctions

Abstract

During inflammation, the disruption of the endothelial barrier leads to increased microvascular permeability. Whether tension along cell junctions contributes to histamine-induced endothelial barrier disruption remains unknown. Rapid Ca2+ influx induced by both histamine and thrombin was accompanied by endothelial barrier breakdown revealed as drop of transendothelial electric resistance in primary human microvascular endothelial cells. 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. Breakdown coincided with increased stress fiber formation but not with translocation of vinculin, which was located along junctions in the resting state similar to postcapillary venules ex vivo. Moreover, increased tension at AJs was indicated by immunostaining with a conformation-sensitive antibody targeting the α18-subunit of α-catenin. Ca2+ chelation by BAPTA-AM and ROCK1 inhibition by Y27632 abolished both increase of tension along AJs as well as barrier dysfunction. Moreover, BAPTA-AM decreased RhoA activation following histamine stimulation, indicating a key role of Ca2+ signaling in barrier breakdown. Taken together, in response to histamine, Ca2+ via RhoA/ROCK activation along endothelial adherens junctions (AJs) appears to be critical for barrier disruption and presumably correlated with enhanced tension. However, vinculin appears not to be critical in this process.

Epac1−/− mice have elevated baseline permeability and do not respond to histamine as measured with dynamic contrast‐enhanced magnetic resonance imaging with contrast agents of different molecular weights

“…A recent study implicates the adherens junctions as being pivotal for the histamine‐induced tension of endothelial cells. The proposed mechanism is that the fibres induced to contract by histamine require anchoring to intact adherens junctions to achieve widening of the intercellular cleft . A working hypothesis that may explain previous observations by others as well as the present findings is therefore that histamine acts to widen the clefts between endothelial cells mainly when they have near basal cAMP/Epac1 stimulation.…”

A natural mouse model reveals genetic determinants of systemic capillary leak syndrome (Clarkson disease)

“…Although Cav3 knockout mice develop heart failure due to myocardial fibrosis and dilated cardiomyopathy 40 , functions of Cav3 in the peripheral vasculature have not been studied in mice. CTNNA2 / Ctnna2 encodes α-catenin 2, which functions as a linker between cadherin adhesion receptors and the cytoskeleton, and thereby regulates cell-cell adhesion dynamically in response to histamine 41 . However, since genome-wide knockout of Ctnna2 in mice is associated with neonatal lethality, with most homozygotes dying with 24 h after birth 42 , vascular-specific deletion of Ctnna2 may be necessary to interrogate its potential role in Histh and SCLS.…”

ROCK1 knockdown inhibits non-small-cell lung cancer progression by activating the LATS2-JNK signaling pathway

“…Several compounds have been identified that inhibit ROCK1 activity and might therefore prove effective for treating NSCLC. For example, histamine [ 52 ], fibroblast-derived hepatocyte growth factor [ 53 ], triptolide [ 54 ], and melatonin [ 55 , 56 ] have been used to inhibit ROCK1 activation. However, additional clinical studies and pre-clinical experiments are needed to support the use of these and other compounds as clinically useful targeted therapeutic agents in NSCLC patients.…”