[ODP22] 5. Pathogenicity -b. Toxins, effectors and physically active substances

[ODP-125/W6-3] Aeromonas sobria serine protease disrupts tight junctions and contributes to bacterial translocation

Hidetomo Kobayashi¹, Soshi Seike¹, Eizo Takahashi², Keinosuke Okamoto³, Hiroyasu Yamanaka¹ (¹Labo. Mol. Microbiol. Sci., Fac. Pharm. Sci., Hiroshima International Univ., ²Labo. Med. Microbiol., Dept. Health Pharm., Yokohama Univ. of Pharmacy, ³Collaborative Research Center of Okayama Univ. for Infect. Diseases in India)

Aeromonas sobria is a pathogen causing food-borne illness. In immunocompromised patients and the elderly, A. sobria opportunistically leads to severe extraintestinal diseases. When A. sobria causes such an extraintestinal infection, the pathogen must pass through the intestinal epithelial barrier. Using intestinal cultured cells (T84 cells), we previously observed that an A. sobria strain with higher serine protease (ASP) production markedly caused bacterial translocation across the T84 intestinal epithelial monolayer. We also observed that ASP acts on adherens junctions (AJs) of T84 cells and causes the destruction of both nectin-2 and afadin. However, not only AJs but also tight junctions (TJs), gap junctions (GPs), and desmosomes contribute to cell-cell junctions of intestinal epithelial cells. Herein, we further investigated the effect of ASP on TJs in T84 cells, and we observed that ASP acts on TJs and causes the destruction of ZO-1, ZO-2, ZO-3, and claudin-7. We therefore propose that ASP may cause a disruption of the barrier function of the intestinal epithelium as a whole due to the destruction of both TJs and AJs, and that ASP promotes the invasion of the pathogens from the intestinal epithelium into the deep parts of the human body.