Changes in the Distribution of Type II Transmembrane Serine Protease, TMPRSS2 and in Paracellular Permeability in IPEC-J2 Cells Exposed to Oxidative Stress

The effect of oxidative stress on barrier integrity and localization of transmembrane serine proteinase 2 (TMPRSS2) were studied using porcine epithelial IPEC-J2 cells on membrane inserts. Increased paracellular permeability of FITC-dextran 4 kDa (fluorescence intensity 43,508 +/- 2,391 versus 3,550 +/- 759) and that of gentamicin (3.41 +/- 0.06 % increase to controls) were measured parallel with the reduced transepithelial electrical resistance (23.3 +/- 4.06 % decrease) of cell layers 6 h after 1 h 1 mM H2O2 treatment. The immunohistochemical localization of adherens junctional beta-catenin was not affected by reactive oxygen species (ROS) up to 4 mM H2O2. Peroxide-triggered enhanced paracellular permeability of IPEC-J2 cell layer was accompanied by predominantly cytoplasmic occurrence of TMPRSS2 embedded in cell membrane under physiological conditions. These results support that ROS can influence paracellular gate opening via multifaceted mode of action without involvement of beta-catenin redistribution in adherens junction. Altered distribution pattern of TMPRSS2 and relocalized transmembrane serine protease activity may contribute to weakening of epithelial barrier integrity under acute oxidative stress.