Pujol C, Eugène E, Marceau M, Nassif X
Laboratoire de Microbiologie, Institut National de la Santé et de la Recherche Médicale Unité 411, Faculté de Médecine Necker-Enfants Malades, 156 rue de Vaugirard, 75730 Paris Cedex 15, France.
Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):4017-22. doi: 10.1073/pnas.96.7.4017.
The ability of Neisseria meningitidis (MC) to interact with cellular barriers is essential to its pathogenesis. With epithelial cells, this process has been modeled in two steps. The initial stage of localized adherence is mediated by bacterial pili. After this phase, MC disperse and lose piliation, thus leading to a diffuse adherence. At this stage, microvilli have disappeared, and MC interact intimately with cells and are, in places, located on pedestals of actin, thus realizing attaching and effacing (AE) lesions. The bacterial attributes responsible for these latter phenotypes remain unidentified. Considering that bacteria are nonpiliated at this stage, pili cannot be directly responsible for this effect. However, the initial phase of pilus-mediated localized adherence is required for the occurrence of diffuse adherence, loss of microvilli, and intimate attachment, because nonpiliated bacteria are not capable of such a cellular interaction. In this work, we engineered a mutation in the cytoplasmic nucleotide-binding protein PilT and showed that this mutation increased piliation and abolished the dispersal phase of bacterial clumps as well as the loss of piliation. Furthermore, no intimate attachment nor AE lesions were observed. On the other hand, PilT- MC remained adherent as piliated clumps at all times. Taken together these data demonstrate that the induction of diffuse adherence, intimate attachment, and AE lesions after pilus-mediated adhesion requires the cytoplasmic PilT protein.
脑膜炎奈瑟菌（MC）与细胞屏障相互作用的能力对其发病机制至关重要。对于上皮细胞，这一过程已被分为两个阶段进行模拟。局部黏附的初始阶段由细菌菌毛介导。在此阶段之后，MC 分散并失去菌毛，从而导致弥漫性黏附。在这个阶段，微绒毛消失，MC 与细胞紧密相互作用，并且在某些部位位于肌动蛋白的基座上，从而形成紧密黏附并抹平（AE）损伤。导致这些后期表型的细菌属性仍未确定。考虑到细菌在此阶段没有菌毛，菌毛不能直接导致这种效应。然而，菌毛介导的局部黏附的初始阶段是弥漫性黏附、微绒毛丧失和紧密黏附发生所必需的，因为没有菌毛的细菌无法进行这种细胞相互作用。在这项工作中，我们对细胞质核苷酸结合蛋白 PilT 进行了突变工程改造，结果表明该突变增加了菌毛形成，并消除了细菌团块的分散阶段以及菌毛丧失。此外，未观察到紧密黏附或 AE 损伤。另一方面，PilT - MC 始终以有菌毛的团块形式保持黏附。综上所述，这些数据表明菌毛介导的黏附后弥漫性黏附、紧密黏附以及 AE 损伤的诱导需要细胞质 PilT 蛋白。
