Lux R, Miller J N, Park N H, Shi W
School of Dentistry and Molecular Biology Institute, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095-1668, USA.
Infect Immun. 2001 Oct;69(10):6276-83. doi: 10.1128/IAI.69.10.6276-6283.2001.
The ability to penetrate tissue is an important virulence factor for pathogenic spirochetes. Previous studies have recognized the role of motility in allowing pathogenic spirochetes to invade tissues and migrate to sites favorable for bacterial proliferation. However, the nature of the movements, whether they are random or controlled by chemotaxis systems, has yet to be established. In this study, we addressed the role of motility and chemotaxis in tissue penetration by the periodontal disease-associated oral spirochete Treponema denticola using an oral epithelial cell line-based experimental approach. Wild-type T. denticola ATCC 35405 was found to penetrate the tissue layers effectively, whereas a nonmotile mutant was unable to overcome the tissue barrier. Interestingly, the chemotaxis mutants also showed impaired tissue penetration. A cheA mutant that is motile but lacks the central kinase of the chemotaxis pathway showed only about 2 to 3% of the wild-type penetration rate. The two known chemoreceptors of T. denticola, DmcA and DmcB, also appear to be involved in the invasion process. The dmc mutants were actively motile but exhibited reduced tissue penetration of about 30 and 10% of the wild-type behavior, respectively. These data suggest that not only motility but also chemotaxis is involved in the tissue penetration by T. denticola.
穿透组织的能力是致病性螺旋体的一个重要毒力因子。先前的研究已经认识到运动性在使致病性螺旋体侵入组织并迁移到有利于细菌增殖的部位中所起的作用。然而，这些运动的性质，无论是随机的还是由趋化系统控制的，尚未确定。在本研究中，我们使用基于口腔上皮细胞系的实验方法，探讨了运动性和趋化性在与牙周病相关的口腔螺旋体齿垢密螺旋体穿透组织中的作用。发现野生型齿垢密螺旋体ATCC 35405能够有效地穿透组织层，而一个不运动的突变体则无法克服组织屏障。有趣的是，趋化性突变体也表现出组织穿透受损。一个具有运动能力但缺乏趋化途径中心激酶的cheA突变体，其穿透率仅为野生型的约2%至3%。齿垢密螺旋体的两个已知化学感受器DmcA和DmcB似乎也参与了入侵过程。dmc突变体具有活跃的运动能力，但组织穿透率分别降低至野生型行为的约30%和10%。这些数据表明，不仅运动性，而且趋化性也参与了齿垢密螺旋体的组织穿透过程。
