title: The development of early host response to Pseudomonas aeruginosa lung infection is critically dependent on myeloid differentiation factor 88 in mice.
abstract: Toll-like receptors (TLR) induce distinct patterns of host responses through myeloid differentiation factor 88 (MyD88)-dependent and/or -independent pathways, depending on the nature of the pathogen. Pseudomonas aeruginosa is a cause of serious lung infection in immunocompromised individuals and cystic fibrosis patients. The role of the TLR-MyD88 pathway in P. aeruginosa-induced lung infection in vivo was examined in this study. MyD88-/- mice demonstrated an impaired clearance of P. aeruginosa from the lung. Little or no neutrophil recruitment was observed in the airways of MyD88-/- mice following P. aeruginosa lung infection. This observation was associated with a reduced production of inflammatory mediators that affect neutrophil recruitment, including macrophage-inflammatory protein-2, tumor necrosis factor, and interleukin-1beta in the airways of MyD88-/- mice. Similarly, MyD88-/- mice showed inhibited NF-kappaB activation in the lung following P. aeruginosa infection. Interestingly, P. aeruginosa infection induced a 7.5-fold increase of TLR2 mRNA expression in the lungs of MyD88+/+ mice. Furthermore, host responses to P. aeruginosa lung infection in TLR2-/- and TLR4 mutant mice were partially inhibited compared with the responses of respective control mice. Taken together, our results indicate that the MyD88-dependent pathway is essential for the development of early host responses to P. aeruginosa infection, leading to the clearance of this bacterium, and that TLR2 and TLR4 are involved in this process.
authors.affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3J 3G9, Canada.
authors.forename: Melanie R
authors.initials: MR
authors.lastname: Power
authors.forename: Yongde
authors.initials: Y
authors.lastname: Peng
authors.forename: Elana
authors.initials: E
authors.lastname: Maydanski
authors.forename: Jean S
authors.initials: JS
authors.lastname: Marshall
authors.forename: Tong-Jun
authors.initials: TJ
authors.lastname: Lin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism / Q000502:physiology*; D001992:Bronchoalveolar Lavage Fluid; D054426:Chemokine CXCL2; D016207:Cytokines / Q000096:biosynthesis; D007375:Interleukin-1 / Q000378:metabolism; D008168:Lung / Q000382:microbiology / Q000473:pathology; D008562:Membrane Glycoproteins / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D015846:Monokines / Q000378:metabolism; D009154:Mutation; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B / Q000378:metabolism; D009504:Neutrophils / Q000382:microbiology; D009195:Peroxidase / Q000378:metabolism; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000502:physiology*; D011971:Receptors, Immunologic / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D054426:Chemokine CXCL2; D016207:Cytokines; D007375:Interleukin-1; D008562:Membrane Glycoproteins; D015846:Monokines; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; D009195:Peroxidase