Leishmania donovani targets tumor necrosis factor receptor-associated factor (TRAF) 3 for impairing TLR4-mediated host response
Leishmania donovani targets tumor necrosis factor receptor-associated factor (TRAF) 3 for impairing TLR4-mediated host response
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DOI：
10.1096/fj.13-238428
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发表时间：
2014-04-01
期刊：
影响因子：
4.8
通讯作者：
Ukil, Anindita
中科院分区：
文献类型：
--
作者：
Gupta, Purnima;Giri, Jayeeta;Ukil, Anindita
巨噬细胞内病原体杜氏利什曼原虫通过破坏 Toll 样受体 (TLR) 信号传导来逃避宿主免疫反应，而 Toll 样受体 (TLR) 信号传导受到蛋白质泛素化的严格调节。在本研究中，我们确定了肿瘤坏死因子受体相关因子 (TRAF) 3（其降解泛素化对于 TLR4 激活至关重要）作为利什曼原虫灭活 LPS 介导的 TLR4 信号传导的靶标。我们使用 LPS 处理的 RAW 264.7 细胞，并将这些细胞中 TLR4 介导的免疫反应与杜氏乳杆菌和杜氏乳杆菌 + LPS 共刺激的巨噬细胞进行比较。 TRAF3 在 lys 48 位点泛素化（是对照的 2.1 倍），随后在 LPS 处理后降解，由于 lys 48 泛素化缺陷，TRAF3 在杜氏乳杆菌和杜氏乳杆菌 + LPS 共刺激细胞中持续存在。级联中上游蛋白（cIAP1/2 和 TRAF6）的赖氨酸 63 连接的泛素化（TRAF3 降解所必需的）在感染后也减少了。这可能是由于感染期间泛素结合酶 Ubc13 和 TRAF6 之间的关联减少。 Balb/c 小鼠在 shRNA 感染前抑制 TRAF3，结果显示 IL-12 和 TNF-α 增强（分别是感染对照的 10.8 倍和 8.1 倍），并减少了脾脏寄生虫负担（抑制 61.3%，P < 0.001），从而标志着疾病进展的减缓。我们的研究结果确定 TRAF3 是利什曼原虫成功感染的新型分子调节因子。-Gupta, P.、Giri, J.、Srivastav, S.、Chande, A. G.、Mukhopadhyaya, R.、Das, P. K.、Ukil, A. 杜氏利什曼原虫靶向肿瘤坏死因子受体相关因子 (TRAF) 3，以损害 TLR4 介导的宿主反应。
Intramacrophage pathogen Leishmania donovani escapes host immune response by subverting Toll-like receptor (TLR) signaling, which is critically regulated by protein ubiquitination. In the present study, we identified tumor necrosis factor receptor-associated factor (TRAF) 3, degradative ubiquitination of which is essential for TLR4 activation, as a target for Leishmania to deactivate LPS-mediated TLR4 signaling. We used LPS-treated RAW 264.7 cells and compared the TLR4-mediated immune response in these cells with L. donovani and L. donovani + LPS costimulated macrophages. TRAF3, which was ubiquitinated (2.1-fold over control) at lys 48 position and subsequently degraded following LPS treatment, persisted in L. donovani and L. donovani + LPS costimulated cells due to defective lys 48 ubiquitination. Lys 63-linked ubiquitination of upstream proteins in the cascade (cIAP1/2 and TRAF6), mandatory for TRAF3 degradation, was also reduced postinfection. This may be attributed to reduced association between ubiquitin-conjugating enzyme Ubc13 and TRAF6 during infection. Inhibition of TRAF3 before infection by shRNA in Balb/c mice showed enhanced IL-12 and TNF-alpha (10.8- and 8.1-fold over infected control) and decreased spleen parasite burden (61.3% suppression, P < 0.001), thereby marking reduction in disease progression. Our findings identified TRAF3 as a novel molecular regulator exploited by Leishmania for successful infection.-Gupta, P., Giri, J., Srivastav, S., Chande, A. G., Mukhopadhyaya, R., Das, P. K., Ukil, A. Leishmania donovani targets tumor necrosis factor receptor-associated factor (TRAF) 3 for impairing TLR4-mediated host response.