[ODP6B] b. 毒素・エフェクター・生理活性物質

[ODP-146] Aeromonas セリンプロテアーゼの腸管上皮バリア破壊機構の解析

○小林 秀丈¹，清家 総史¹，高橋 栄造²，岡本 敬の介³，山中 浩泰¹ (¹広島国際大・薬・分子微生物科学，²横浜薬科大・感染予防学，³岡山大学院・医歯薬・インド感染症共同研究センター)

Aeromonas is a pathogen causing food-borne illness. In immunocompromised patients, however, the symptoms may progress to severe extraintestinal diseases. To cause such extraintestinal diseases, Aeromonas must pass through the intestinal epithelial barrier. The mechanism of such bacterial translocation has not been established. Herein we used intestinal (T84) cultured cells to investigate the effect of Aeromonas serine protease (ASP) on junctional complexes that maintain the intercellular adhesion of the intestinal epithelium. When several Aeromonas strains were inoculated into T84 monolayer grown on Transwell inserts, the strain with higher ASP production markedly caused bacterial translocation from the apical surface into the basolateral side of T84 monolayer. Western blotting analysis revealed that degradation of zona occludens proteins (ZO-1, ZO-2 and ZO-3) and claudin-7 were observed in highly permeable bacteria strains. Further experiments revealed that ASP acts on tight junctions (TJs) and causes the destruction of ZO proteins and claudin-7, which are components of TJs. We therefore speculate that the destruction of ZO proteins and claudin-7 by the action of ASP increases the ability of Aeromonas to pass through intestinal epithelial tissue and contributes to the severity of pathological conditions.