Serine protease‐induced decrease in epithelial ion permeability is dependent on an intact actin cytoskeleton

Abstract

The serine proteases trypsin, chymotrypsin and elastase induce a sustained increase in transepithelial electrical resistance (RTE) when applied to the apical surface of polarised epithelial cell monolayers that is reflected by decreases in Na+ and Cl− paracellular permeabilities. Paracellular permeability is controlled at the intercellular tight junctions and the adherens junctions, with the epithelial actin cytoskeleton linked to proteins comprising both. We show that manipulation of the actin cytoskeleton with latruculin B and jasplakinolide reduces the protease‐induced increase in RTE by 92 ± 5 and 50 ± 8% respectively. Immunocytostaining for F‐ and G‐ actin indicate a shift in the filamentous actin pool. Inhibition of Rho kinases decreased baseline RTE but did not inhibit the protease‐induced increase in RTE.