Expression and translocation of chlamydial protease during acute and persistent infection of the epithelial HEp-2 cells with Chlamydophila (Chlamydia) pneumoniae
Expression and translocation of chlamydial protease during acute and persistent infection of the epithelial HEp-2 cells with Chlamydophila (Chlamydia) pneumoniae
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DOI：
10.1046/j.1462-5822.2003.00278.x
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发表时间：
2003-05-01
影响因子：
3.4
通讯作者：
Szczepek, AJ
中科院分区：
文献类型：
--
作者：
Heuer, D;Brinkmann, V;Szczepek, AJ
衣原体蛋白酶样活性因子（CPAF）分泌到感染细胞的细胞质中，在那里它蛋白水解切割真核转录因子RFX 5。在这里，我们确定了本地化模式的CPAF过程中的急性和持续的上皮细胞系HEp-2与肺炎衣原体菌株VR 1310的体外感染。使用免疫印迹，共聚焦显微镜和电子显微镜，我们发现CPAF在包涵体腔或与细菌在第一个48小时的急性感染。72小时后，CPAF主要存在于感染细胞的细胞质中。免疫印迹证实，CPAF向细胞质中的转运与转录因子RFX 5的降解时间相关。有趣的是，在由IFN-γ或铁限制诱导的持续感染期间，CPAF向细胞质的易位被抑制，导致RFX 5的水平不受影响或仅部分降低。基于所提出的研究结果，我们提出，CPAF易位到细胞质是从其生产中分离的。在急性感染期间，易位机制似乎是完全活跃的;然而，在IFN-γ或铁限制分别诱导的持续感染期间，其被完全或部分抑制。因此，这项工作表明CPAF的亚细胞定位的重要性，衣原体的急性和持续感染上皮HEp-2细胞的特点。
Chlamydial protease-like activity factor (CPAF) is secreted to the cytoplasm of the infected cells where it proteolytically cleaves eukaryotic transcription factor RFX5. Here, we determined the localization pattern of CPAF during the course of an acute and persistent in vitro infection of the epithelial cell line HEp-2 with Chlamydophila pneumoniae strain VR1310. Using immunoblotting, confocal microscopy and electron microscopy, we found CPAF in the inclusion lumen or associated with bacteria during the first 48 h of an acute infection. Seventy-two hours and later, CPAF was present predominantly in the cytoplasm of the infected cells. Translocation of CPAF into cytoplasm correlated in time with degradation of the transcription factor RFX5, as confirmed by immunoblotting. Interestingly, during the persistent infection induced by either IFN-gamma or iron limitation CPAF translocation to the cytoplasm was inhibited resulting in unaffected or only partially reduced levels of RFX5. Based on presented findings, we propose that CPAF translocation to the cytoplasm is separated from its production. The translocation mechanism appears to be fully active during an acute infection; however, it is fully or partially inhibited during persistent infection induced by IFN-gamma or by iron limitation respectively. Consequently, this work demonstrates the importance of subcellular localization of CPAF for the characteristics of chlamydial acute and persistent infection in epithelial HEp-2 cells.