title: Pseudomonas aeruginosa Transmigrates at Epithelial Cell-Cell Junctions, Exploiting Sites of Cell Division and Senescent Cell Extrusion.
abstract: To achieve systemic infection, bacterial pathogens must overcome the critical and challenging step of transmigration across epithelial barriers. This is particularly true for opportunistic pathogens such as Pseudomonas aeruginosa, an agent which causes nosocomial infections. Despite extensive study, details on the mechanisms used by this bacterium to transmigrate across epithelial tissues, as well as the entry sites it uses, remain speculative. Here, using real-time microscopy and a model epithelial barrier, we show that P. aeruginosa employs a paracellular transmigration route, taking advantage of altered cell-cell junctions at sites of cell division or when senescent cells are expelled from the cell layer. Once a bacterium transmigrates, it is followed by a cohort of bacteria using the same entry point. The basal compartment is then invaded radially from the initial penetration site. Effective transmigration and propagation require type 4 pili, the type 3 secretion system (T3SS) and a flagellum, although flagellum-deficient bacteria can occasionally invade the basal compartment from wounded areas. In the basal compartment, the bacteria inject the T3SS toxins into host cells, disrupting the cytoskeleton and focal contacts to allow their progression under the cells. Thus, P. aeruginosa exploits intrinsic host cell processes to breach the epithelium and invade the subcellular compartment.
authors.affiliation: University Grenoble Alpes, Grenoble, France.|CNRS, ERL5261, Grenoble, France.|CEA, iRTSV-BCI, Grenoble, France.|INSERM, U1036, Grenoble, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Golovkine
authors.affiliation: University Grenoble Alpes, Grenoble, France.|CNRS, ERL5261, Grenoble, France.|CEA, iRTSV-BCI, Grenoble, France.|INSERM, U1036, Grenoble, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Faudry
authors.affiliation: University Grenoble Alpes, Grenoble, France.|CNRS, ERL5261, Grenoble, France.|CEA, iRTSV-BCI, Grenoble, France.|INSERM, U1036, Grenoble, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Bouillot
authors.affiliation: University Grenoble Alpes, Grenoble, France.|CNRS, ERL5261, Grenoble, France.|CEA, iRTSV-BCI, Grenoble, France.|INSERM, U1036, Grenoble, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Elsen
authors.affiliation: University Grenoble Alpes, Grenoble, France.|CNRS, ERL5261, Grenoble, France.|CEA, iRTSV-BCI, Grenoble, France.|INSERM, U1036, Grenoble, France.
authors.forename: Ina
authors.initials: I
authors.lastname: Attrée
authors.affiliation: University Grenoble Alpes, Grenoble, France.|CNRS, ERL5261, Grenoble, France.|CEA, iRTSV-BCI, Grenoble, France.|INSERM, U1036, Grenoble, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Huber
mesh_terms: D000818:Animals; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D016922:Cellular Senescence / Q000502:physiology; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007365:Intercellular Junctions / Q000378:metabolism; D061985:Madin Darby Canine Kidney Cells; D018613:Microscopy, Confocal; D011552:Pseudomonas Infections / Q000821:virology*; D011550:Pseudomonas aeruginosa / Q000472:pathogenicity*; D014162:Transfection