VE-cadherin cleavage by LasB protease from Pseudomonas aeruginosa facilitates type III secretion system toxicity in endothelial cells.
VE-cadherin cleavage by LasB protease from Pseudomonas aeruginosa facilitates type III secretion system toxicity in endothelial cells.
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DOI：
10.1371/journal.ppat.1003939
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发表时间：
2014-03
期刊：
影响因子：
6.7
通讯作者：
Huber P
中科院分区：
文献类型：
--
作者：
Golovkine G;Faudry E;Bouillot S;Voulhoux R;Attrée I;Huber P
铜绿假单胞菌（Pa）对血管系统的感染发生在体内细菌传播或血液传播感染期间。来自Pa的3型分泌系统（T3 SS）毒素在注射到内皮细胞中时诱导大量收缩。在这里，我们解决了2型分泌系统（T2 SS）效应在这一过程中的作用。具有失活T2 SS的突变体在诱导细胞收缩方面比野生型菌株有效得多。此外，当应用于细胞时，野生型的分泌组足以触发细胞间连接打开，而T2 SS失活突变体的活性最低。中毒与血管内皮（VE）-钙粘蛋白（一种位于内皮细胞-细胞连接处的嗜同性粘附蛋白）水平降低有关。在此过程中，蛋白质在其胞外结构域的中间（位置335和349）被切割。VE-钙粘蛋白消耗是T3 SS独立的，但T2 SS依赖。有趣的是，上皮（E）-钙粘蛋白不受T2 SS效应物的影响，表明这种机制对内皮细胞是特异性的。我们发现，T2 SS效应子之一，蛋白酶LasB，直接影响VE-钙粘蛋白的蛋白水解，从而促进细胞间连接的破坏。此外，小鼠感染Pa诱导急性肺炎导致肺VE-钙粘蛋白水平显著降低，而T2 SS失活或LasB缺失突变株的降低最小。我们得出结论，T2 SS在Pa感染的血管系统中发挥了关键作用，通过突破内皮屏障，并提出了一个模型，其中T2 SS和T3 SS合作中毒内皮细胞。 铜绿假单胞菌（Pseudomonasaeruginosa，Pa）是人类医院感染的主要病原体，临床分离株往往对抗生素具有多重耐药性。与大多数革兰氏阴性细菌一样，Pa具有III型分泌系统，其由注射体组成，细菌通过注射体注射外毒素，诱导细胞骨架崩溃和细胞凋亡。Pa还通过II型分泌系统在细胞外环境中递送各种毒素，包括蛋白酶LasB。为了从感染部位扩散到全身并最终到达血液，细菌通常需要穿过生物体的主要屏障：上皮、基底层和血管内皮。在这里，我们表明，LasB特异性切割内皮细胞与细胞连接的一个主要组成部分，粘附蛋白VE-钙粘蛋白，从而导致连接中断和内皮屏障破坏。VE-钙粘蛋白的蛋白水解也促进了III型外毒素在内皮细胞中的作用。正如我们在小鼠中的细菌传播实验所表明的那样，这种切割机制可能在Pa发病机制中具有重要意义。
Infection of the vascular system by Pseudomonas aeruginosa (Pa) occurs during bacterial dissemination in the body or in blood-borne infections. Type 3 secretion system (T3SS) toxins from Pa induce a massive retraction when injected into endothelial cells. Here, we addressed the role of type 2 secretion system (T2SS) effectors in this process. Mutants with an inactive T2SS were much less effective than wild-type strains at inducing cell retraction. Furthermore, secretomes from wild-typeswere sufficient to trigger cell-cell junction opening when applied to cells, while T2SS-inactivated mutants had minimal activity. Intoxication was associated with decreased levels of vascular endothelial (VE)-cadherin, a homophilic adhesive protein located at endothelial cell-cell junctions. During the process, the protein was cleaved in the middle of its extracellular domain (positions 335 and 349). VE-cadherin attrition was T3SS-independent but T2SS-dependent. Interestingly, the epithelial (E)-cadherin was unaffected by T2SS effectors, indicating that this mechanism is specific to endothelial cells. We showed that one of the T2SS effectors, the protease LasB, directly affected VE-cadherin proteolysis, hence promoting cell-cell junction disruption. Furthermore, mouse infection with Pa to induce acute pneumonia lead to significant decreases in lung VE-cadherin levels, whereas the decrease was minimal with T2SS-inactivated or LasB-deleted mutant strains. We conclude that the T2SS plays a pivotal role during Pa infection of the vascular system by breaching the endothelial barrier, and propose a model in which the T2SS and the T3SS cooperate to intoxicate endothelial cells. Pseudomonas aeruginosa (Pa) is a leading agent of nosocomial infections in humans, and clinical isolates are often multiresistant to antibiotics. As with most Gram-negative bacteria, Pa possesses a type III secretion system which consists of an injectisome through which the bacterium injects exotoxins inducing cytoskeleton collapse and apoptosis. Pa also delivers various toxins in the extracellular milieu by the type II secretion system, including the protease LasB. In order to disseminate throughout the body from the infection site and eventually reach the blood, the bacterium generally needs to cross the main barriers of the organism: the epithelium, the basal lamina and the vascular endothelium. Here we show that LasB specifically cleaves one main component of endothelial cell-to-cell junctions, the adhesive protein VE-cadherin, thus leading to junction disruption and endothelial barrier breakdown. VE-cadherin proteolysis also facilitates the action of type III exotoxins in endothelial cells. This cleavage mechanism is likely of major importance in Pa pathogenesis, as suggested by our bacterial dissemination experiments in mice.
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影响因子：
20.3
作者：
Corada, M;Liao, F;Dejana, E
通讯作者：
Dejana, E
DOI：
10.1016/0090-1229(92)90065-v
发表时间：
1992-02-01
期刊：
CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY
影响因子：
--
作者：
HONG, YQ;GHEBREHIWET, B
通讯作者：
GHEBREHIWET, B
影响因子：
2.1
作者：
Pastor, A;Chabert, J;Attree, I
通讯作者：
Attree, I
DOI：
10.1038/nrmicro2199
发表时间：
2009-09
期刊：
Nature reviews. Microbiology
影响因子：
--
作者：
通讯作者：
--
影响因子：
4.8
作者：
Hermant, B;Bibert, S;Gulino-Debrac, D
通讯作者：
Gulino-Debrac, D