Deoxynucleic acids from Cryptococcus neoformans activate myeloid dendritic cells via a TLR9-dependent pathway
Deoxynucleic acids from Cryptococcus neoformans activate myeloid dendritic cells via a TLR9-dependent pathway
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DOI：
10.4049/jimmunol.180.6.4067
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发表时间：
2008-03-15
影响因子：
4.4
通讯作者：
Kawakami, Kazuyoshi
中科院分区：
文献类型：
--
作者：
Nakamura, Kiwamu;Miyazato, Akiko;Kawakami, Kazuyoshi
新型隐球菌是免疫功能低下患者中的一种机会致病真菌，其宿主细胞识别机制仍知之甚少。在本研究中，我们问这种酵母的DNA是否激活小鼠骨髓来源的髓样树突状细胞（BM-DCs）。BM-DCs在隐球菌DNA刺激下释放IL-12 p40并表达CD 40，DNase处理可消除这种反应，但RNase不能。IL-12 p40的产生和CD 40的表达被氯喹、巴弗洛霉素A和抑制性寡脱氧核苷酸（ODN）减弱，所述抑制性寡脱氧核苷酸（ODN）抑制由CpG-ODN引起的反应。隐球菌DNA对TLR 9基因敲除（TLR 9（-/-））小鼠和MyD 88（-/-）小鼠BM-DCs的激活作用几乎完全消失，与CpG-ODN相似。此外，在用无囊新生隐球菌的完整酵母细胞刺激后，TLR 9（-/-）BM-DCs产生的IL-12 p40的量低于野生型小鼠，并且TLR 9（-/-）小鼠比野生型小鼠更容易受到这种真菌病原体的肺部感染，如肺中活菌落数量增加所示。用甲基化酶处理隐球菌DNA导致BM-DCs合成IL-12 p40减少。此外，使用荧光素酶报告基因测定，隐球菌DNA激活转染TLR 9基因的HEK 293细胞中的NF-κ B。最后，共聚焦显微镜显示荧光标记的隐球菌DNA与CpG-ODN共定位，并且该结果与TLR 9在BM-DCs中的分布部分合并。我们的研究结果表明，隐球菌DNA引起BM-DCs的TLR 9依赖性的方式激活，并建议CpG基序的DNA可能有助于感染后的炎症反应的发展。新人类
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-kappa B 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.