Pathogen-mediated proteolysis of the cell death regulator RIPK1 and the host defense modulator RIPK2 in human aortic endothelial cells.
Pathogen-mediated proteolysis of the cell death regulator RIPK1 and the host defense modulator RIPK2 in human aortic endothelial cells.
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DOI：
10.1371/journal.ppat.1002723
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发表时间：
2012
期刊：
影响因子：
6.7
通讯作者：
Genco CA
中科院分区：
文献类型：
--
作者：
Madrigal AG;Barth K;Papadopoulos G;Genco CA
牙龈卟啉单胞菌是牙周病的主要病原体，与包括动脉粥样硬化在内的其他人类慢性炎症性疾病有关。牙龈假单胞菌侵袭并持续存在于人主动脉内皮细胞(HAEC)的能力被认为是导致低到中度慢性炎症状态的原因，尽管这一点具体是如何实现的还没有很好的定义。在这项研究中，我们证明了牙龈假单胞菌感染HAEC导致受体相互作用蛋白1(RIPK1)和RIPK2的快速裂解，RIPK1是肿瘤坏死因子受体1(TNF-R1)诱导的细胞激活或死亡的中介，RIPK2是天然免疫信号和获得性免疫的关键中介。RIPK1或RIPK2在经细胞凋亡刺激或受肿瘤坏死因子-R1、核苷酸寡聚结构域受体1(NOD1)、NOD2、Toll样受体2(TLR2)或TLR4激动剂刺激的细胞中均未观察到裂解。牙龈假单胞菌诱导的RIPK1和RIPK2的切割在赖氨酸特异性牙周疼痛(KGP)抑制剂的存在下被抑制。在HAEC中没有观察到RIPK1和RIPK2的裂解，证实了KGP在RIPK1和RIPK2的裂解中的作用。聚腺苷二磷酸核糖聚合酶(PARP)也有类似的蛋白降解。我们还证明了牙龈假单胞菌在无细胞体系中对RIPK2的直接蛋白分解，该体系在KGP特异性蛋白酶抑制剂的存在下被取消。因此，我们的研究揭示了病原体介导的细胞激酶修饰作为细菌在目标宿主细胞内持续存在的潜在策略的重要作用，这与低级别慢性炎症有关，这是病原体介导的慢性炎症性疾病的标志。一些成功的病原体已经进化出逃避宿主防御的机制，从而建立了持续和慢性感染。尽管包括Toll样受体在内的膜结合的天然免疫受体在口腔常见病原体牙龈卟啉单胞菌的炎症反应中发挥了作用，但目前尚不清楚细胞内对这种病原体的防御机制是如何促进持续感染和导致慢性炎症的。在这项研究中，我们定义了一种新的策略，通过它来调节参与细胞死亡和宿主防御反应的关键细胞内蛋白的水平。我们证明了牙龈假单胞菌赖氨酸特异的细菌半胱氨酸蛋白酶(KGP)可以诱导受体相互作用蛋白激酶1(RIPK1)、RIPK2和多聚ADP核糖聚合酶(PARP)的蛋白分解。尽管内源性宿主机制可能参与了这一过程，但仅靠激活先天免疫信号级联、半胱氨酸天冬氨酸氨基转移酶或细胞凋亡并不足以推动蛋白分解。这些发现支持病原体介导的细胞激酶修饰作为细菌在目标宿主细胞内持续存在的一种策略。与其他最近描述的牙龈假单胞菌宿主免疫逃避机制一起，我们的工作支持这样一个新的概念，即病原体介导的慢性炎症疾病是由特定的病原体介导的逃避策略导致的，从而导致低级别的慢性炎症。
Porphyromonas gingivalis is the primary etiologic agent of periodontal disease that is associated with other human chronic inflammatory diseases, including atherosclerosis. The ability of P. gingivalis to invade and persist within human aortic endothelial cells (HAEC) has been postulated to contribute to a low to moderate chronic state of inflammation, although how this is specifically achieved has not been well defined. In this study, we demonstrate that P. gingivalis infection of HAEC resulted in the rapid cleavage of receptor interacting protein 1 (RIPK1), a mediator of tumor necrosis factor (TNF) receptor-1 (TNF-R1)-induced cell activation or death, and RIPK2, a key mediator of both innate immune signaling and adaptive immunity. The cleavage of RIPK1 or RIPK2 was not observed in cells treated with apoptotic stimuli, or cells stimulated with agonists to TNF-R1, nucleotide oligomerization domain receptor 1(NOD1), NOD2, Toll-like receptor 2 (TLR2) or TLR4. P. gingivalis-induced cleavage of RIPK1 and RIPK2 was inhibited in the presence of a lysine-specific gingipain (Kgp) inhibitor. RIPK1 and RIPK2 cleavage was not observed in HAEC treated with an isogenic mutant deficient in the lysine-specific gingipain, confirming a role for Kgp in the cleavage of RIPK1 and RIPK2. Similar proteolysis of poly (ADP-ribose) polymerase (PARP) was observed. We also demonstrated direct proteolysis of RIPK2 by P. gingivalis in a cell-free system which was abrogated in the presence of a Kgp-specific protease inhibitor. Our studies thus reveal an important role for pathogen-mediated modification of cellular kinases as a potential strategy for bacterial persistence within target host cells, which is associated with low-grade chronic inflammation, a hallmark of pathogen-mediated chronic inflammatory disorders. A number of successful pathogens have evolved mechanisms to evade host defenses, thus establishing persistent and chronic infections. Although membrane-bound innate immune receptors including Toll-like receptors play a role in inflammation in response to the common oral pathogen Porphyromonas gingivalis, it is not known how intracellular host defense mechanisms to this pathogen contribute to persistent infection and resulting chronic inflammation. In this study, we have defined a novel strategy by which P. gingivalis modulates the levels of key intracellular proteins involved in cell death and host defense responses. We demonstrate that the lysine-specific bacterial cysteine protease of P. gingivalis (Kgp) induces the proteolysis of receptor interacting protein kinase 1 (RIPK1), RIPK2 and poly (ADP-ribose) polymerase (PARP). Although endogenous host mechanisms may contribute to this process, activation of innate immune signaling cascades, caspases, or apoptosis alone were not sufficient to drive proteolysis. These findings support a role for pathogen-mediated modification of cellular kinases as a strategy for bacterial persistence within target host cells. Together with other recently described mechanisms for P. gingivalis host immune evasion, our work supports the emerging concept that pathogen-mediated chronic inflammatory disorders result from specific pathogen-mediated evasion strategies resulting in low-grade chronic inflammation.
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影响因子：
32.4
作者：
Bertrand, Mathieu J. M.;Doiron, Karine;Saleh, Maya
通讯作者：
Saleh, Maya
影响因子：
3.1
作者：
Bielig, H.;Rompikuntal, P. K.;Kufer, T. A.
通讯作者：
Kufer, T. A.
影响因子：
7.3
作者：
Bialas, A;Grembecka, J;Mucha, A
通讯作者：
Mucha, A
影响因子：
3.1
作者：
Chou, HH;Yumoto, H;Genco, CA
通讯作者：
Genco, CA
RIP3 的裂解通过去除激酶结构域使其不依赖 caspase 的细胞凋亡途径失活
影响因子：
4.8
作者：
Feng, Shanshan;Yang, Yonghui;Wu, Mian
通讯作者：
Wu, Mian