Induction of Native c-di-GMP Phosphodiesterases Leads to Dispersal of Pseudomonas aeruginosa Biofilms

Abstract

A decade of research has shown that the molecule c-di-GMP functions as a central second messenger in many bacteria. A high level of c-di-GMP is associated with biofilm formation whereas a low level of c-di-GMP is associated with a planktonic single-cell bacterial lifestyle. C-di-GMP is formed by diguanylate cyclases and is degraded by specific phosphodiesterases. We have previously presented evidence that ectopic expression in Pseudomonas aeruginosa of the Escherichia coli phosphodiesterase YhjH results in biofilm dispersal. More recently, however, evidence has been presented that induction of native c-di-GMP phosphodiesterases does not lead to dispersal of P. aeruginosa biofilms. The latter result may discourage attempts to use c-di-GMP signaling as a target for development of anti-biofilm drugs. However, here we demonstrate that induction of the P. aeruginosa c-di-GMP phosphodiesterases PA2133 and BifA indeed does result in dispersal of P. aeruginosa biofilms in both a microtiter tray biofilm assay and in a flow-cell biofilm system.

Identification of small molecules that interfere with c-di-GMP signaling and induce dispersal of Pseudomonas aeruginosa biofilms

“…On the contrary, Sauer and coworkers reported that induction of native PDEs does not lead to dispersal of P. aeruginosa biofilms [63][64][65] . In the present study, we provide evidence that H6-335-P1-mediated activation of BifA is sufficient to induce dispersal of P. aeruginosa biofilms, which is in accordance with our previous findings 11 . In our previous study, we used two different P. aeruginosa strains with inducible native PDE genes; one that harbored a P BAD -bifA fusion and one that harbored a P BAD -PA2133 fusion.…”

“…Through the use of PDE genes engineered with inducible promoters, we have previously demonstrated that induction of PDEs inhibits P. aeruginosa biofilm formation and results in dispersal of already established P. aeruginosa biofilms 8,11 . On the contrary, Sauer and coworkers reported that induction of native PDEs does not lead to dispersal of P. aeruginosa biofilms [63][64][65] .…”

“…Accordingly, H6-335-P1-mediated activation of ectopically expressed BifA in E. coli would strongly indicate that BifA is the direct target of H6-335-P1. We transformed E. coli AR3110 with, respectively, the pJN105 vector and plasmid pJN105::bifA 11 , enabling ectopic expression of BifA by induction with arabinose. The E. coli AR3110 strain has intact cellulose biosynthesis genes and forms red colonies on CR agar plates, as the cellulose binds CR 37 .…”

“…In response to a variety of environmental and chemical signals, a number of different DGC and PDE enzymes modulate the internal c-di-GMP content either by catalyzing the synthesis or the breakdown of cdi-GMP. We have previously provided evidence that induction of PDEs in Pseudomonas putida and Pseudomonas aeruginosa leads to biofilm dispersal [8][9][10][11] . In the case of P. aeruginosa, this was demonstrated in vitro as well as in a murine biofilm infection model 8,11 .…”

“…We have previously provided evidence that induction of PDEs in Pseudomonas putida and Pseudomonas aeruginosa leads to biofilm dispersal [8][9][10][11] . In the case of P. aeruginosa, this was demonstrated in vitro as well as in a murine biofilm infection model 8,11 . Owing to the highly conserved nature of c-di-GMP signaling systems in Gram-negative bacteria and the strong evidence for their role in regulating biofilm formation, c-di-GMP signaling systems are promising targets for the development of drugs for the treatment of biofilm-associated infections in combination with antibiotics capable of killing planktonic bacteria [12][13][14] .…”