Recruitment and endo-lysosomal activation of TLR9 in dendritic cells infected with Trypanosoma cruzi
Recruitment and endo-lysosomal activation of TLR9 in dendritic cells infected with Trypanosoma cruzi
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DOI：
10.4049/jimmunol.181.2.1333
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发表时间：
2008-07-15
影响因子：
4.4
通讯作者：
Gazzinelli, Ricardo T.
中科院分区：
文献类型：
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作者：
Bartholomeu, Daniella C.;Ropert, Catherine;Gazzinelli, Ricardo T.
TLR 9在寄生虫识别和宿主对克氏锥虫实验感染的抗性中至关重要。然而，没有关于T上涉及的核苷酸序列和细胞事件的信息。通过TLR 9的cruzi识别。与体外筛选合成寡核苷酸相关的计算机模拟分析表明，T. cruzi基因组高度富集分别对小鼠和人TLR 9具有免疫刺激性的CpG基序。重要的是，T. cruzi在与人TLR 9共转染的HEK细胞中在NF-κ B依赖性转录下触发高水平的荧光素酶活性，但在对照（与人MD 2/TLR 4共转染）HEK细胞中不触发。此外，我们观察到TLR 9在T.克氏寄生虫通过树突状细胞。一致地，当高度未甲基化的T.将cruzi基因组DNA递送至表达TLR 9的宿主细胞的内溶酶体区室。因此，我们的研究结果表明，在T. cruzi基因组可能是主要的寄生虫靶标，并且当寄生虫在寄生虫入侵/被吞噬细胞摄取期间在溶酶体融合的空泡中被破坏时，可能变得可用于TLR 9。
TLR9 is critical in parasite recognition and host resistance to experimental infection with Trypanosoma cruzi. However, no information is available regarding nucleotide sequences and cellular events involved on T. cruzi recognition by TLR9. In silico wide analysis associated with in vitro screening of synthetic oligonucleotides demonstrates that the retrotransposon VIPER elements and mucin-like glycoprotein (TcMUC) genes in the T. cruzi genome are highly enriched for CpG motifs that are immunostimulatory for mouse and human TLR9, respectively. Importantly, infection with T. cruzi triggers high levels of luciferase activity under NF-kappa B-dependent transcription in HEK cells cotransfected with human TLR9, but not in control (cotransfected with human MD2/TLR4) HEK cells. Further, we observed translocation of TLR9 to the lysosomes during invasion/uptake of T. cruzi parasites by dendritic cells. Consistently, potent proinflammatory activity was observed when highly unmethylated T. cruzi genomic DNA was delivered to the endo-lysosomal compartment of host cells expressing TLR9. Thus, together our results indicate that the unmethylated CpG motifs found in the T. cruzi genome are likely to be main parasite targets and probably become available to TLR9 when parasites are destroyed in the lysosome-fused vacuoles during parasite invasion/uptake by phagocytes.