title: Activation of NF-κB and respiratory burst following Aspergillus fumigatus stimulation of macrophages.
abstract: Dectin-2, a C-type lectin receptor (CLR), plays an essential role in mediating nuclear factor-kappa B (NF-κB) activation and anti-fungal immunity in response to Candida albicans infection. However, the molecular mechanisms and function of Dectin-2 signaling in response to infection by the pathogenic fungus Aspergillus fumigatus have not been characterized. In order to characterize Dectin-2 signaling in response to A. fumigatus infection, activation of Dectin-2 was analyzed at both transcriptional and translational levels. Spleen tyrosine kinase (Syk) phosphorylation, NF-κB activation and cytokine production downstream of Dectin-2 activation were also investigated. In addition, Dectin-2-Syk function and its ability to mediate reactive oxygen species (ROS) production and elimination of A. fumigatus conidia was examined. We demonstrate that Syk is involved in Dectin-2-induced IκBα (inhibitor of kappa B protein) phosphorylation and NF-κB activation following A. fumigatus stimulation in a time dependent manner. Silencing of Dectin-2 and Syk as well as Syk inhibition blocks NF-κB activation and cytokine secretion. Furthermore, the killing of A. fumigatus conidia and ROS production are significantly affected by Dectin-2 or Syk silencing as well as Syk inhibition. Swelling and germination of the fungus followed by hyphae formation and not the resting and heat-inactivated form of A. fumigatus mediate the activation of Dectin-2 signaling. In conclusion, Syk plays an essential role in IκBα kinase phosphorylation, NF-κB activation, and ROS production mediated by Dectin-2 activation in response to A. fumigatus infection.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Jinling Hospital, Clinical School of Nanjing, Second Military Medical University, Nanjing 210002, China.
authors.forename: He
authors.initials: H
authors.lastname: Sun
authors.forename: Xiao-yong
authors.initials: XY
authors.lastname: Xu
authors.forename: Xiao-li
authors.initials: XL
authors.lastname: Tian
authors.forename: Hong-tao
authors.initials: HT
authors.lastname: Shao
authors.forename: Xiao-dong
authors.initials: XD
authors.lastname: Wu
authors.forename: Quan
authors.initials: Q
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Su
authors.forename: Yi
authors.initials: Y
authors.lastname: Shi
mesh_terms: D001232:Aspergillus fumigatus / Q000276:immunology* / Q000502:physiology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression / Q000276:immunology; D054884:Host-Pathogen Interactions / Q000276:immunology; D006801:Humans; D025301:Hyphae / Q000276:immunology / Q000502:physiology; D051550:I-kappa B Kinase / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D037181:Lectins, C-Type / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D010766:Phosphorylation / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000276:immunology / Q000378:metabolism; D016897:Respiratory Burst / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013172:Spores, Fungal / Q000276:immunology / Q000502:physiology; D000072377:Syk Kinase; D013997:Time Factors
chemical_list: D016207:Cytokines; D047908:Intracellular Signaling Peptides and Proteins; D037181:Lectins, C-Type; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; D051550:I-kappa B Kinase
keywords: Aspergillus fumigatus; B cell lymphoma 10; BCL10; C-type lectin receptors; CARD9; CLRs; Dectin-2; Fc receptor γ chain; FcRγ; GAPDH; IKK; IL-10; IL-12p70; IL-1β; IL-23p19; ITAM; IκBα; MALT1; MAPK; MOI; NADPH; NF-κB; PMA; ROS; Reactive oxygen species; SDS; SOD; Syk; Syk kinase; T helper cell type 1; T helper cell type 17; TLRs; TNF-α; Th1; Th17; Toll-like receptors; caspase recruitment domain 9; glyceraldehyde-3-phosphate dehydrogenase; immunoreceptor tyrosine-based activation-like motif; inhibitor of kappa B protein; interleukin-10; interleukin-12 subunit p70; interleukin-1β; interleukin-23 subunit p19; mitogen-activated protein kinase; mucosa-associated lymphoid tissue lymphoma-translocation gene 1; multiplicity of infection; nicotinamide-adenine dinucleotide phosphate; nuclear factor-kappa B; phorbol-12-myristate-13-acetate; reactive oxygen species; sodium dodecyl sulfate; spleen tyrosine kinase; superoxide dismutases; the IκBα kinase; tumor necrosis factor-α