title: Calcium signalling during cell interactions with bacterial pathogens.
abstract: The ability of a pathogenic microorganism to cause a disease is conditioned by its ability to colonise a given niche and implicates the expression of specific determinants, i.e. virulence factors, that allow the pathogen to adhere to or to invade epithelial cells. Diseases may be induced by bacteria that replicate extracellularly and alter the epithelial mucosa by producing toxins. Ca2+ signalling has been implicated in various steps of bacterial infection. Bacterial toxins can induce an increase in free cytosolic Ca2+ in host cells, itself required for the toxin-mediated effects. Such toxins, by diffusing in the extracellular media, can act at a distance from the site of infection and have a global effect on the integrity of the epithelium by promoting the expression of pro-inflammatory cytokines. Independent on toxins, bacteria can induce Ca2+ responses that play a role in cytoskeletal rearrangements required for cell binding or internalisation of the microorganism. In some instances, invasion of the epithelium may be followed by bacterial access to deeper tissue, dissemination to other organs, and sometimes persistence in host cells in a parasitic-like mode. Such strategies underline the pathogen abilities to control innate defence cells such as professional phagocytes, and may implicate the diversion of Ca(2+)-dependent cellular processes that normally result in killing of the ingested bacteria. Finally, bacterial pathogens can also induce the cell release of ATP, a Ca2+ agonist, that may expand bacterial cell signalling by a paracrine or autocrine route, leading to enhanced colonisation or enhanced host cell responses to the invading microorganism.
authors.affiliation: Unité de Pathogénie Microbienne Moléculaire, INSERM U389, Institut Pasteur, 75724 Paris Cedex 15, France. gtranvan@pasteur.fr
authors.forename: Guy
authors.initials: G
authors.lastname: TranVan Nhieu
authors.forename: Caroline
authors.initials: C
authors.lastname: Clair
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Grompone
authors.forename: Philippe
authors.initials: P
authors.lastname: Sansonetti
mesh_terms: D000818:Animals; D001424:Bacterial Infections / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology*; D020013:Calcium Signaling / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism; D010586:Phagocytes / Q000276:immunology / Q000378:metabolism
chemical_list: D016328:NF-kappa B