title: VE-cadherin cleavage by LasB protease from Pseudomonas aeruginosa facilitates type III secretion system toxicity in endothelial cells.
abstract: 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-types were 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.
authors.affiliation: INSERM, U1036, Biology of Cancer and Infection, Grenoble, France; CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France; Université Joseph Fourier-Grenoble I, Grenoble, France; CEA, DSV/iRTSV, Grenoble, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Golovkine
authors.affiliation: INSERM, U1036, Biology of Cancer and Infection, Grenoble, France; CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France; Université Joseph Fourier-Grenoble I, Grenoble, France; CEA, DSV/iRTSV, Grenoble, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Faudry
authors.affiliation: INSERM, U1036, Biology of Cancer and Infection, Grenoble, France; CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France; Université Joseph Fourier-Grenoble I, Grenoble, France; CEA, DSV/iRTSV, Grenoble, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Bouillot
authors.affiliation: CNRS and Aix-Marseille Univ, Laboratoire d'Ingénierie des Systèmes Macromoléculaires (UMR7255), Marseille, France.
authors.forename: Romé
authors.initials: R
authors.lastname: Voulhoux
authors.affiliation: INSERM, U1036, Biology of Cancer and Infection, Grenoble, France; CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France; Université Joseph Fourier-Grenoble I, Grenoble, France; CEA, DSV/iRTSV, Grenoble, France.
authors.forename: Ina
authors.initials: I
authors.lastname: Attrée
authors.affiliation: INSERM, U1036, Biology of Cancer and Infection, Grenoble, France; CNRS, ERL 5261, Bacterial Pathogenesis and Cellular Responses, Grenoble, France; Université Joseph Fourier-Grenoble I, Grenoble, France; CEA, DSV/iRTSV, Grenoble, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Huber
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D058947:Bacterial Secretion Systems / Q000502:physiology*; D015153:Blotting, Western; D015820:Cadherins / Q000378:metabolism*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D008666:Metalloendopeptidases / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D011552:Pseudomonas Infections / Q000378:metabolism*; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D015820:Cadherins; D008666:Metalloendopeptidases; D000099152:Cadherin 5; C043859:pseudolysin, Pseudomonas aeruginosa