title: Lipopolysaccharide enhances bactericidal activity in Dictyostelium discoideum cells.
abstract: Innate immune cells respond to invading microbes upon detection of pathogen-associated molecular patterns (PAMPS). PAMP-recognition machinery is evolutionarily conserved, allowing for characterization in model organisms. The model organism Dictyostelium discoideum can exist as single-celled amoebae, which phagocytize bacteria for nutrients. Although D. discoideum is used extensively to study phagocytosis, it has not been determined if D. discoideum detects bacterial PAMPs using pattern-recognition machinery. Here we show that D. discoideum mounts responses against the bacterial cell wall PAMP, lipopolysaccharide (LPS). Upon treatment with LPS or its active component Lipid A, D. discoideum cells more efficiently clear phagocytized bacteria. LPS-enhanced bactericidal activity appears dependent both on MAPK signaling pathways as well as on the D. discoideum toll/interleukin-1 receptor domain-containing protein, TirA. These findings indicate that pattern-recognition machinery required to detect and respond to bacterial PAMPs may be conserved in D. discoideum.
authors.affiliation: Department of Biological Sciences, Towson University, MD 21252-0001, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Walk
authors.forename: Jennifer
authors.initials: J
authors.lastname: Callahan
authors.forename: Pat
authors.initials: P
authors.lastname: Srisawangvong
authors.forename: Jessica
authors.initials: J
authors.lastname: Leuschner
authors.forename: Dave
authors.initials: D
authors.lastname: Samaroo
authors.forename: Daniel
authors.initials: D
authors.lastname: Cassilly
authors.forename: Michelle L D
authors.initials: ML
authors.lastname: Snyder
mesh_terms: D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D004023:Dictyostelium / Q000187:drug effects / Q000382:microbiology*; D055786:Gene Knockout Techniques; D006090:Gram-Negative Bacteria / Q000166:cytology; D006094:Gram-Positive Bacteria / Q000166:cytology; D008050:Lipid A / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D050296:Microbial Viability; D010587:Phagocytosis / Q000187:drug effects / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D051192:Receptors, Pattern Recognition / Q000378:metabolism*; D000099173:Natural Resistance-associated Macrophage Protein 1
chemical_list: D027682:Cation Transport Proteins; D008050:Lipid A; D008070:Lipopolysaccharides; D015800:Protozoan Proteins; D051192:Receptors, Pattern Recognition; D000099173:Natural Resistance-associated Macrophage Protein 1