TY - JOUR
T1 - Deoxynucleic acids from Cryptococcus neoformans activate myeloid dendritic cells via a TLR9-dependent pathway
AU - Nakamura, Kiwamu
AU - Miyazato, Akiko
AU - Xiao, Gang
AU - Hatta, Masumitsu
AU - Inden, Ken
AU - Aoyagi, Tetsuji
AU - Shiratori, Kohei
AU - Takeda, Kiyoshi
AU - Akira, Shizuo
AU - Saijo, Shinobu
AU - Iwakura, Yoichiro
AU - Adachi, Yoshiyuki
AU - Ohno, Naohito
AU - Suzuki, Kazuo
AU - Fujita, Jiro
AU - Kaku, Mitsuo
AU - Kawakami, Kazuyoshi
PY - 2008/3/15
Y1 - 2008/3/15
N2 - 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-κB 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.
AB - 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-κB 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.
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U2 - 10.4049/jimmunol.180.6.4067
DO - 10.4049/jimmunol.180.6.4067
M3 - Article
C2 - 18322216
AN - SCOPUS:44849093666
VL - 180
SP - 4067
EP - 4074
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 6
ER -