RRC ID 46911
Author Bhatia S, Fei M, Yarlagadda M, Qi Z, Akira S, Saijo S, Iwakura Y, van Rooijen N, Gibson GA, St Croix CM, Ray A, Ray P.
Title Rapid host defense against Aspergillus fumigatus involves alveolar macrophages with a predominance of alternatively activated phenotype.
Journal PLoS One
Abstract The ubiquitous fungus Aspergillus fumigatus is associated with chronic diseases such as invasive pulmonary aspergillosis in immunosuppressed patients and allergic bronchopulmonary aspergillosis (ABPA) in patients with cystic fibrosis or severe asthma. Because of constant exposure to this fungus, it is critical for the host to exercise an immediate and decisive immune response to clear fungal spores to ward off disease. In this study, we observed that rapidly after infection by A. fumigatus, alveolar macrophages predominantly express Arginase 1 (Arg1), a key marker of alternatively activated macrophages (AAMs). The macrophages were also found to express Ym1 and CD206 that are also expressed by AAMs but not NOS2, which is expressed by classically activated macrophages. The expression of Arg1 was reduced in the absence of the known signaling axis, IL-4Rα/STAT6, for AAM development. While both Dectin-1 and TLR expressed on the cell surface have been shown to sense A. fumigatus, fungus-induced Arg1 expression in CD11c(+) alveolar macrophages was not dependent on either Dectin-1 or the adaptor MyD88 that mediates intracellular signaling by most TLRs. Alveolar macrophages from WT mice efficiently phagocytosed fungal conidia, but those from mice deficient in Dectin-1 showed impaired fungal uptake. Depletion of macrophages with clodronate-filled liposomes increased fungal burden in infected mice. Collectively, our studies suggest that alveolar macrophages, which predominantly acquire an AAM phenotype following A. fumigatus infection, have a protective role in defense against this fungus.
Volume 6(1)
Pages e15943
Published 2011-1-5
DOI 10.1371/journal.pone.0015943
PMID 21246055
PMC PMC3016416
MeSH Animals Arginase / immunology Aspergillus fumigatus / immunology* Cells, Cultured Gene Expression Immunity Lectins, C-Type Macrophages, Alveolar / immunology* Macrophages, Alveolar / metabolism Macrophages, Alveolar / microbiology* Membrane Proteins / immunology Mice Nerve Tissue Proteins / immunology Opportunistic Infections Phagocytosis / immunology Phenotype
IF 2.74
Times Cited 62
WOS Category IMMUNOLOGY
Resource
Pathogenic microorganisms