title: Lipopolysaccharide induction of autophagy is associated with enhanced bactericidal activity in Dictyostelium discoideum.
abstract: Innate immune cells respond to microbial invaders using pattern recognition receptors that detect conserved microbial patterns. Among the cellular processes stimulated downstream of pattern recognition machinery is the initiation of autophagy, which plays protective roles against intracellular microbes. We have shown recently that Dictyostelium discoideum, which takes up bacteria for nutritive purposes, may employ pattern recognition machinery to respond to bacterial prey, as D. discoideum cells upregulate bactericidal activity upon stimulation by lipopolysaccharide (LPS). Here we extend these findings, showing that LPS treatment leads to induction of autophagosomal maturation in cells responding to the bacteria Staphylococcus aureus. Cells treated with the autophagy-inducing drug rapamycin clear internalized bacteria at an accelerated rate, while LPS-enhanced clearance of bacteria is reduced in cells deficient for the autophagy-related genes atg1 and atg9. These findings link microbial pattern recognition with autophagy in the social amoeba D. discoideum.
authors.affiliation: Department of Biological Sciences, Towson University, 8000 York Rd, Towson, MD 21252-0001, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Pflaum
authors.forename: Kimberly
authors.initials: K
authors.lastname: Gerdes
authors.forename: Kossi
authors.initials: K
authors.lastname: Yovo
authors.forename: Jennifer
authors.initials: J
authors.lastname: Callahan
authors.forename: Michelle L D
authors.initials: ML
authors.lastname: Snyder
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001343:Autophagy / Q000187:drug effects / Q000276:immunology*; D004023:Dictyostelium / Q000276:immunology / Q000382:microbiology*; D008070:Lipopolysaccharides / Q000276:immunology*; D010588:Phagosomes / Q000276:immunology / Q000382:microbiology*; D020123:Sirolimus / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000276:immunology
chemical_list: D000900:Anti-Bacterial Agents; D008070:Lipopolysaccharides; D020123:Sirolimus