Pseudomonas virulence and OprF

http://www.ncbi.nlm.nih.gov/pubmed/21189321

Infect Immun. 2010 Dec 28. [Epub ahead of print]
Full virulence of Pseudomonas aeruginosa requires OprF.
Fito-Boncompte L, Chapalain A, Bouffartigues E, Chaker H, Lesouhaitier O, Gicquel G, Bazire A, Madi A, Connil N, Véron W, Taupin L, Toussaint B, Cornelis P, Wei Q, Shioya K, Déziel E, Feuilloley MG, Orange N, Dufour A, Chevalier S.

Laboratoire de Microbiologie du Froid, Signaux et Micro-environnement. EA 4312. Normandie Sécurité Sanitaire. Université de Rouen (France); Laboratoire de Biotechnologie et Chimie Marines. EA 3884. Université de Bretagne Sud, UEB, Lorient (France); Laboratory of Microbial interactions, Department of Molecular and Cellular Interactions, Flanders Institute of Biotechnology (VIB), Vrije Universiteit Brussel (Belgium); INRS-Institut Armand-Frappier, Laval, Québec (Canada); TIMC-IMAG, TheREx, Thérapeutiques recombinantes expérimentales, UMR5525 CNRS-Université Joseph Fourier, Grenoble (France).
Abstract
OprF is a general outer membrane porin of Pseudomonas aeruginosa, a well known human opportunistic pathogen associated with severe hospital-acquired sepsis and chronic lung infections of cystic fibrosis patients. A multiphenotypic approach, based on the comparative study of a wildtype strain of P. aeruginosa, its isogenic mutant oprF and the oprF complemented strain, showed that OprF is required for P. aeruginosa virulence. The absence of OprF results in impaired adhesion to animal cells, secretion of ExoT and ExoS toxins through the type III secretion system (T3SS), and production of the quorum sensing-dependent virulence factors pyocyanin, elastase, lectin PA-1L and exotoxin A. Accordingly, in the oprF mutant, production of the signal molecules N-(3-oxododecanoyl)-L-homoserine lactone and N-butanoyl-L-homoserine lactone was found to be reduced or delayed, respectively. The Pseudomonas Quinolone Signal (PQS) production was decreased while its precursor the 4-hydroxy-2-heptylquinoline (HHQ) accumulated in the cells. Taken together, these results show the involvement of OprF in P. aeruginosa virulence, at least partly through modulation of the quorum sensing network. This is the first study showing a link between OprF, PQS synthesis, T3SS and virulence factor production, providing novel insights on virulence expression.