Identification of the host factors involved in the response of macrophage cells to Legionella pneumophila infection

为了研究NAIP5在巨噬细胞存活中的作用，构建了表达NAIP5的RAW264巨噬细胞。Naip5可促进嗜肺军团菌感染细胞的细胞毒作用。这种细胞毒性与caspase-1有关。此外，Naip5还抑制了嗜肺乳杆菌在RAW264细胞内的生长。嗜肺乳杆菌鞭毛蛋白是细胞毒性、激活caspase-1和限制细胞内细菌生长所必需的。此外，Naip5还能抑制喜树碱诱导的巨噬细胞凋亡。这些数据表明，Naip5通过抑制细胞凋亡或促进特定细胞信号的下垂来调节细胞存活。

To investigate the role of Naip5 in macrophage survival, RAW264 macrophages expressing Naip5 were constructed. Naip5 promoted cytotoxicity in Legionella pneumophila-infected cells. This cytotoxicity was associated with caspase-1. In addition, Naip5 restricted the intracellular growth of L. pneumophila in RAW264 cells. L. pneumophila flagellin was required for cytotoxicity, caspase-1 activation, and restriction of intracellular bacterial growth. Moreover, Naip5 inhibited camptothecin-induced apoptosis in macrophages. These data indicate that Naip5 regulate cell survival by inhibiting apoptosis or by promoting pyroptosis in response to specific cellular signals.