Raw data of Fig 9.

B. parapertussis is one of the etiological agents of whooping cough. Once inhaled, the bacteria bind to the respiratory epithelium and start the infection. Little is known about this first step of host colonization and the role of the human airway epithelial barrier on B. parapertussis infection. We here investigated the outcome of the interaction of B. parapertussis with a polarized monolayer of respiratory epithelial cells. Our results show that B. parapertussis preferentially attaches to the intercellular boundaries, and causes the disruption of the tight junction integrity through the action of adenylate cyclase toxin (CyaA). We further found evidence indicating that this disruption enables the bacterial access to components of the basolateral membrane of epithelial cells to which B. parapertussis efficiently attaches and gains access to the intracellular location, where it can survive and eventually spread back into the extracellular environment. Altogether, these results suggest that the adenylate cyclase toxin enables B. parapertussis to overcome the epithelial barrier and eventually establish a niche of persistence within the respiratory epithelial cells.

副百日咳博德特氏菌（B. parapertussis）是百日咳（whooping cough）的病原体之一。该细菌经呼吸道吸入后，可黏附于呼吸道上皮组织并启动感染过程。目前针对宿主定植的这一首要步骤，以及人类气道上皮屏障在副百日咳博德特氏菌感染中所发挥的作用，学界仍所知有限。本研究针对副百日咳博德特氏菌与极化呼吸道上皮单层细胞的相互作用结局开展了探究。研究结果显示，副百日咳博德特氏菌优先黏附于细胞间边界，并通过腺苷酸环化酶毒素（adenylate cyclase toxin, CyaA）的作用破坏紧密连接的完整性。本研究进一步发现相关证据表明，这种紧密连接破坏可使细菌接触上皮细胞基底外侧膜的组分；副百日咳博德特氏菌可高效黏附于该组分，并进入细胞内定位，在此处存活并最终扩散回细胞外环境。综上，上述结果表明腺苷酸环化酶毒素可帮助副百日咳博德特氏菌突破上皮屏障，并最终在呼吸道上皮细胞内建立持续定植的微环境。