Dictyostelium transcriptional host cell response upon infection with Legionella

Abstract

SummaryDifferential gene expression of Dictyostelium discoideum after infection with Legionella pneumophila was investigated using DNA microarrays. Investigation of a 48 h time course of infection revealed several clusters of co-regulated genes, an enrichment of preferentially up-or downregulated genes in distinct functional categories and also showed that most of the transcriptional changes occurred 24 h after infection. A detailed analysis of the 24 h time point post infection was performed in comparison to three controls, uninfected cells and co-incubation with Legionella hackeliae and L. pneumophila ∆ ∆ ∆ ∆ dotA . One hundred and thirty-one differentially expressed D. discoideum genes were identified as common to all three experiments and are thought to be involved in the pathogenic response. Functional annotation of the differentially regulated genes revealed that apart from triggering a stress response Legionella apparently not only interferes with intracellular vesicle fusion and destination but also profoundly influences and exploits the metabolism of its host. For some of the identified genes, e.g. rtoA involvement in the host response has been demonstrated in a recent study, for others such a role appears plausible. The results provide the basis for a better understanding of the complex host-pathogen interactions and for further studies on the Dictyostelium response to Legionella infection.

Burkholderia bacteria infectiously induce the proto-farming symbiosis of Dictyostelium amoebae and food bacteria

“…If food bacteria associate with Burkholderia-colonized fruiting bodies, what excludes food bacteria from these developing structures in noncolonized clones? The bacterial pathogens Legionella pneumophila and Mycobacterium species replicate and spread intracellularly within D. discoideum host cells by subverting a variety of host functions (50)(51)(52)(53)(54)(55). To our knowledge, susceptibility to secondary bacterial carriage has not been observed or specifically analyzed during D. discoideum infections with these bacterial pathogens.…”

Phosphoinositides differentially regulate bacterial uptake and Nramp1-induced resistance toLegionellainfection inDictyostelium

“…Despite the very low uptake, ingested Legionella survive and proliferate efficiently in Dictyostelium cells, as already shown by different labs (Farbrother et al, 2006;Hagele et al, 2000;Peracino et al, 1998;Solomon and Isberg, 2000;Weber et al, 2006). To investigate the involvement of phosphoinositides in Legionella infection, we first assayed Legionella growth in pi3k-null and/or pten-null mutants.…”

Dictyostelium Finds New Roles to Model

“…The complementary, more global approach, of identifying cellular components that change in response to Legionella infection, has also been informative. Expression profiling reveals changes in the expression of 5% of the genes represented on the array, and many of these encoded components that might be expected to be regulated in response to infection (Farbrother et al 2006). Purification of Legionella containing phagosomes from cells infected with Legionella and analysis of their proteome have given further insights into the infection process (Shevchuk et al 2009).…”