title: Human transcriptome analysis reveals a potential role for active transport in the metabolism of Pseudomonas aeruginosa autoinducers.
abstract: The opportunistic pathogen Pseudomonas aeruginosa employs acyl homoserine lactones (AHL) as signaling compounds to regulate virulence gene expression via quorum sensing. The AHL N-3-oxo-dodecanoyl-l-homoserine lactone (3OC(12)-HSL) also induces mammalian cell responses, including apoptosis and immune modulation. In certain cell types the apoptotic effects of 3OC(12)-HSL are mediated via a calcium-dependent signaling pathway, while some pro-inflammatory effects involve intracellular transcriptional regulators. However, the mechanisms by which mammalian cells perceive and respond to 3OC(12)-HSL are still not completely understood. Here we used microarray analysis to investigate the transcriptional response of human lung epithelial cells after exposure to 3OC(12)-HSL. These data revealed that mRNA levels for several genes involved in xenobiotic sensing and drug transport were increased in cells exposed to 3OC(12)-HSL, which led us to examine the intracellular fate of 3OC(12)-HSL. Using radiolabeled autoinducer uptake assays, we discovered that intracellular 3OC(12)-HSL levels increased after exposure and achieved maximal levels after 20-30 min. Intracellular 3OC(12)-HSL decreased to background levels over the next 90 min and this process was blocked by pre-treatment with an inhibitor of the ABC transporter ABCA1. Taken together, these data suggest that mammalian cells detect 3OC(12)-HSL and activate protective mechanisms to expel it from the cell.
authors.affiliation: Dept. of Cell Biology & Biochemistry, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Bryan
authors.forename: Chase
authors.initials: C
authors.lastname: Watters
authors.forename: Lars
authors.initials: L
authors.lastname: Koenig
authors.forename: Eunseog
authors.initials: E
authors.lastname: Youn
authors.forename: Aaron
authors.initials: A
authors.lastname: Olmos
authors.forename: Guigen
authors.initials: G
authors.lastname: Li
authors.forename: Simon C
authors.initials: SC
authors.lastname: Williams
authors.forename: Kendra P
authors.initials: KP
authors.lastname: Rumbaugh
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002478:Cells, Cultured; D003593:Cytoplasm / Q000737:chemistry; D004847:Epithelial Cells / Q000187:drug effects* / Q000276:immunology*; D020869:Gene Expression Profiling; D006714:Homoserine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D053858:Metabolic Networks and Pathways / Q000235:genetics; D051379:Mice; D046228:Microarray Analysis; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation
chemical_list: C109860:N-(3-oxododecanoyl)homoserine lactone; D006714:Homoserine; D015107:4-Butyrolactone