PilY1 Promotes Legionella pneumophila Infection of Human Lung Tissue Explants and Contributes to Bacterial Adhesion, Host Cell Invasion, and Twitching Motility.
PilY1 Promotes Legionella pneumophila Infection of Human Lung Tissue Explants and Contributes to Bacterial Adhesion, Host Cell Invasion, and Twitching Motility.
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DOI：
10.3389/fcimb.2017.00063
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发表时间：
2017
影响因子：
5.7
通讯作者：
Steinert M
中科院分区：
文献类型：
--
作者：
Hoppe J;Ünal CM;Thiem S;Grimpe L;Goldmann T;Gaßler N;Richter M;Shevchuk O;Steinert M
军团病是一种急性纤维蛋白脓性肺炎。在感染过程中，嗜肺军团菌粘附在肺泡内壁，并在募集的巨噬细胞内进行细胞内复制。在这里，我们提供了一个序列和结构域组成分析的L。pneumophila PilY 1蛋白，其与铜绿假单胞菌的PilY 1具有高度同源性。两种病原体的PilY 1蛋白都含有血管性血友病因子A（vWFa）和C-末端PilY结构域。使用细胞分级，我们将L。pneumophila PilY 1作为外膜蛋白，其仅在透射稳定生长期期间表达。PilY 1有助于感染人肺组织外植体（HLTEs）。使用THP-1巨噬细胞和A549肺上皮细胞的详细分析揭示，这种贡献是由于取决于宿主细胞类型的多种效应。PilY 1的缺失导致THP-1巨噬细胞的复制率降低，但在A549细胞中没有。进一步，与THP-1巨噬细胞和A549上皮细胞的粘附减少。此外，当PilY 1不存在时，对非吞噬性A549上皮细胞的侵袭显著减少。PilY 1阴性突变体的互补变体显示，C-末端PilY结构域对于恢复粘附中的野生型表型是必不可少的，而pupillin机械敏感性vWFa结构域促进侵入非吞噬细胞。由于PilY 1也促进L. pneumophila，我们讨论了这种新描述的毒力因子感染的肺组织内的细菌传播的假定贡献。
Legionnaires' disease is an acute fibrinopurulent pneumonia. During infection Legionella pneumophila adheres to the alveolar lining and replicates intracellularly within recruited macrophages. Here we provide a sequence and domain composition analysis of the L. pneumophila PilY1 protein, which has a high homology to PilY1 of Pseudomonas aeruginosa. PilY1 proteins of both pathogens contain a von Willebrand factor A (vWFa) and a C-terminal PilY domain. Using cellular fractionation, we assigned the L. pneumophila PilY1 as an outer membrane protein that is only expressed during the transmissive stationary growth phase. PilY1 contributes to infection of human lung tissue explants (HLTEs). A detailed analysis using THP-1 macrophages and A549 lung epithelial cells revealed that this contribution is due to multiple effects depending on host cell type. Deletion of PilY1 resulted in a lower replication rate in THP-1 macrophages but not in A549 cells. Further on, adhesion to THP-1 macrophages and A549 epithelial cells was decreased. Additionally, the invasion into non-phagocytic A549 epithelial cells was drastically reduced when PilY1 was absent. Complementation variants of a PilY1-negative mutant revealed that the C-terminal PilY domain is essential for restoring the wild type phenotype in adhesion, while the putatively mechanosensitive vWFa domain facilitates invasion into non-phagocytic cells. Since PilY1 also promotes twitching motility of L. pneumophila, we discuss the putative contribution of this newly described virulence factor for bacterial dissemination within infected lung tissue.