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Co‐regulation of Transcellular and Paracellular Leak Across Microvascular Endothelium By Dynamin and Rac
Author(s) -
Lee Warren Lester,
Armstrong Susan,
Khajoee Vahid,
Wang Changsen,
Wang Tieling,
Tigdi Jayesh,
Yin Jun,
Kuebler Wolfgang M.,
Gillrie Mark,
Davis Shevaun,
Ho May
Publication year - 2012
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.26.1_supplement.862.1
Subject(s) - paracellular transport , transcytosis , transcellular , microbiology and biotechnology , dynamin , endocytosis , vascular permeability , internalization , chemistry , biology , biochemistry , permeability (electromagnetism) , endocrinology , receptor , membrane
Increased permeability of the endothelium is the hallmark of inflammation. Leakage can occur between (paracellular) or through (transcytosis) endothelial cells, yet little is known about whether these pathways are linked. We investigated whether transcytosis and paracellular leakage are co‐regulated. Using molecular and pharmacologic approaches, we inhibited transcytosis of albumin in primary human microvascular endothelium and measured paracellular permeability. Blockade of transcytosis induced an increase in paracellular leak that was not explained by decreases in caveolin‐1 or by increased activity of nitric oxide synthase. The effect required caveolin‐1 but occurred in cells depleted of clathrin, indicating that it was not due to the general inhibition of endocytosis. Inhibiting transcytosis by blocking dynamin increased paracellular leak concomitantly with the loss of cortical actin from the plasma membrane and the displacement of active Rac from the plasmalemma. Importantly, inhibition of paracellular leak by sphingosine‐1‐phosphate, which activates Rac and induces cortical actin, caused a significant increase in transcytosis of albumin in vitro and in an ex vivo whole lung model. Dominant‐negative Rac diminished albumin uptake by endothelia. Thus, transcytosis and paracellular permeability are co‐regulated through a signalling pathway linking dynamin, Rac and actin.