VE-Cadherin Cleavage by LasB Protease from Pseudomonas aeruginosa Facilitates Type III Secretion System Toxicity in Endothelial Cells

PLoS Pathogens

Romé Voulhoux¹  Philippe Huber²  Eric Faudry²  Guillaume Golovkine³  Ina Attrée³  Stéphanie Bouillot⁴ 

[1] CEA, DSV/iRTSV, Grenoble, France;CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France;INSERM, U1036, Biology of Cancer and Infection, Grenoble, France;Université Joseph Fourier-Grenoble I, Grenoble, France

关键词: Secretion systems;    Pseudomonas aeruginosa;    Proteases;    Endothelial cells;    Actins;    Mouse models;    Tight junctions;    Cell disruption;   

DOI  :  10.1371/journal.ppat.1003939

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

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.

【 授权许可】

CC BY