Ehrlichia chaffeensis Tandem Repeat Effector Targets Differentially Influence Infection.
Ehrlichia chaffeensis Tandem Repeat Effector Targets Differentially Influence Infection.
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DOI：
10.3389/fcimb.2017.00178
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发表时间：
2017
影响因子：
5.7
通讯作者：
McBride JW
中科院分区：
文献类型：
--
作者：
Luo T;Dunphy PS;McBride JW
恰菲埃里希体感染单核吞噬细胞，并通过利用宿主细胞过程逃避宿主防御而在细胞内存活。所涉及的机制尚未完全确定，但似乎很大程度上依赖于串联重复蛋白（TRP）效应子的子集。查菲埃里希菌 TRP 是 1 型分泌效应器，可与与各种生物过程相关的功能多样的宿主细胞靶标相互作用。在本研究中，我们通过 RNA 干扰研究了 TRP 宿主靶蛋白对埃利希体感染的影响。总共 138 个由酵母双杂交体鉴定出的 TRP 相互作用宿主蛋白被 siRNA 靶向，并通过实时 qPCR 确定感染水平。 124 个 (89%) TRP 靶蛋白的敲低通过抑制 (85%) 或促进 (15%) 埃利希体感染对感染产生显着影响。值得注意的是，敲低与 TRP120 相互作用的 18 个宿主蛋白促进了感染，表明这些靶标可能被降解以促进感染。与 TRP 相互作用的宿主蛋白参与细胞过程，包括细胞信号传导、囊泡运输和细胞内运输、转录调节、代谢、蛋白质翻译后修饰和细胞凋亡。在感染过程中通过免疫荧光显微镜检查选定的宿主靶标，发现它们位于桑葚胚内，或位于桑葚胚附近的宿主细胞细胞质中。这项研究证实，大多数已知与 TRP 效应子相互作用的宿主蛋白都会影响感染，并进一步扩展了目前的知识，即查菲埃里希菌 TRP 参与一系列复杂的宿主蛋白相互作用，以重新编程宿主细胞并促进细胞内存活。
Ehrlichia chaffeensis infects mononuclear phagocytes and survives intracellularly by exploiting host cell processes to evade host defenses. The mechanisms involved are not fully defined, but appear to rely largely on a subset of tandem repeat proteins (TRP) effectors. E. chaffeensis TRPs are type 1 secreted effectors that interact with a functionally diverse group of host cell targets associated with various biological processes. In this study, we investigated the influence of TRP host target proteins on ehrlichial infection by RNA interference. In total, 138 TRP-interacting host proteins identified by yeast two-hybrid were targeted by siRNA and the infection level determined by real-time qPCR. Knockdown of 124 (89%) TRP target proteins had significant influence on infection either by inhibiting (85%) or promoting (15%) ehrlichial infection. Notably, knockdown of 18 host proteins which interacted with TRP120 promoted the infection, suggesting that these targets may be degraded to promote infection. Host proteins that interact with TRPs are involved in cellular processes, including cell signaling, vesicle trafficking and intracellular transport, transcriptional regulation, metabolism, protein posttranslational modification, and apoptosis. Selected host targets were examined by immunofluorescent microscopy during infection and were found to localize with the morulae, or in the host cell cytoplasm adjacent to morulae. This study confirms that the majority of host proteins known to interact with TRP effectors influence infection and further extends the current knowledge that E. chaffeensis TRPs participate in a complex array of host protein interactions in order to reprogram the host cell and promote intracellular survival.