RRC ID 43293
Author Nakamura K, Miyazato A, Xiao G, Hatta M, Inden K, Aoyagi T, Shiratori K, Takeda K, Akira S, Saijo S, Iwakura Y, Adachi Y, Ohno N, Suzuki K, Fujita J, Kaku M, Kawakami K.
Title Deoxynucleic acids from Cryptococcus neoformans activate myeloid dendritic cells via a TLR9-dependent pathway.
Journal J Immunol
Abstract The mechanism of host cell recognition of Cryptococcus neoformans, an opportunistic fungal pathogen in immunocompromised patients, remains poorly understood. In the present study, we asked whether the DNA of this yeast activates mouse bone marrow-derived myeloid dendritic cells (BM-DCs). BM-DCs released IL-12p40 and expressed CD40 upon stimulation with cryptococcal DNA, and the response was abolished by treatment with DNase, but not with RNase. IL-12p40 production and CD40 expression were attenuated by chloroquine, bafilomycin A, and inhibitory oligodeoxynucleotides (ODN) that suppressed the responses caused by CpG-ODN. Activation of BM-DCs by cryptococcal DNA was almost completely abrogated in TLR9 gene-disrupted (TLR9(-/-)) mice and MyD88(-/-) mice, similar to that by CpG-ODN. In addition, upon stimulation with whole yeast cells of acapsular C. neoformans, TLR9(-/-) BM-DCs produced a lower amount of IL-12p40 than those from wild-type mice, and TLR9(-/-) mice were more susceptible to pulmonary infection with this fungal pathogen than wild-type mice, as shown by increased number of live colonies in lungs. Treatment of cryptococcal DNA with methylase resulted in reduced IL-12p40 synthesis by BM-DCs. Furthermore, using a luciferase reporter assay, cryptococcal DNA activated NF-kappaB in HEK293 cells transfected with the TLR9 gene. Finally, confocal microscopy showed colocalization of fluorescence-labeled cryptococcal DNA with CpG-ODN and the findings merged in part with the distribution of TLR9 in BM-DCs. Our results demonstrate that cryptococcal DNA causes activation of BM-DCs in a TLR9-dependent manner and suggest that the CpG motif-containing DNA may contribute to the development of inflammatory responses after infection with C. neoformans.
Volume 180(6)
Pages 4067-74
Published 2008-3-15
DOI 10.4049/jimmunol.180.6.4067
PII 180/6/4067
PMID 18322216
MeSH Animals Bone Marrow Cells / immunology Bone Marrow Cells / metabolism Cells, Cultured Cryptococcus neoformans / chemistry* Cryptococcus neoformans / immunology* DNA, Fungal / metabolism DNA, Fungal / physiology* Dendritic Cells / immunology* Dendritic Cells / metabolism Female Humans Interleukin-12 Subunit p40 / metabolism Male Mice Mice, Inbred C57BL Mice, Knockout Myeloid Cells / immunology* Myeloid Cells / metabolism Oligodeoxyribonucleotides / metabolism Oligodeoxyribonucleotides / pharmacology Signal Transduction / immunology* Toll-Like Receptor 9 / deficiency Toll-Like Receptor 9 / genetics Toll-Like Receptor 9 / physiology*
IF 4.718
Times Cited 71
Human and Animal Cells