Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
Institute of Microbiology, University Cattolica del Sacro Cuore, Rome, Italy.
Sci Rep. 2017 Jul 4;7(1):4581. doi: 10.1038/s41598-017-04875-3.
The commensal bacterium Enterococcus faecalis is a common cause of nosocomial infections worldwide. The increasing prevalence of multi-antibiotic resistant E. faecalis strains reinforces this public health concern. Despite numerous studies highlighting several pathology-related genetic traits, the molecular mechanisms of E. faecalis virulence remain poorly understood. In this work, we studied 23 bacterial proteins that could be considered as virulence factors or involved in the Enterococcus interaction with the host. We systematically tested their interactions with human proteins using the Human ORFeome library, a set of 12,212 human ORFs, in yeast. Among the thousands of tested interactions, one involving the E. faecalis virulence factor ElrA and the human protein FHL2 was evidenced by yeast two-hybrid and biochemically confirmed. Further molecular characterizations allowed defining an FHL2-interacting domain (FID) of ElrA. Deletion of the FID led to an attenuated in vivo phenotype of the mutated strain clearly indicating that this interaction is likely to contribute to the multifactorial virulence of this opportunistic pathogen. Altogether, our results show that FHL2 is the first host cellular protein directly targeted by an E. faecalis virulence factor and that this interaction is involved in Enterococcus pathogenicity.
共生菌粪肠球菌是全世界医院感染的常见原因。越来越多的多抗生素耐药粪肠球菌菌株的出现加剧了这一公共卫生问题。尽管有许多研究强调了几种与病理学相关的遗传特征，但粪肠球菌毒力的分子机制仍知之甚少。在这项工作中，我们研究了 23 种细菌蛋白，这些蛋白可以被认为是毒力因子或参与肠球菌与宿主的相互作用。我们使用酵母中的人类 ORFeome 文库（一组 12212 个人类 ORF）系统地测试了它们与人类蛋白的相互作用。在数千种测试的相互作用中，通过酵母双杂交和生化验证证实了一种涉及粪肠球菌毒力因子 ElrA 和人类蛋白 FHL2 的相互作用。进一步的分子特征分析确定了 ElrA 的 FHL2 相互作用结构域（FID）。FID 的缺失导致突变菌株的体内表型减弱，这清楚地表明这种相互作用可能有助于这种机会性病原体的多因素毒力。总之，我们的研究结果表明，FHL2 是第一个被粪肠球菌毒力因子直接靶向的宿主细胞蛋白，并且这种相互作用参与了肠球菌的致病性。
