The aliphatic amidase AmiE is involved in regulation of Pseudomonas aeruginosa virulence

© The Author(s) 2017.We have previously shown that the eukaryotic C-type natriuretic peptide hormone (CNP) regulates Pseudomonas aeruginosa virulence and biofilm formation after binding on the AmiC sensor, triggering the amiE transcription. Herein, the involvement of the aliphatic amidase AmiE in P. aeruginosa virulence regulation has been investigated. The proteome analysis of an AmiE over-producing strain (AmiE +) revealed an expression change for 138 proteins, including some that are involved in motility, synthesis of quorum sensing compounds and virulence regulation. We observed that the AmiE + strain produced less biofilm compared to the wild type, and over-produced rhamnolipids. In the same line, AmiE is involved in P. aeruginosa motilities (swarming and twitching) and production of the quorum sensing molecules N-acyl homoserine lactones and Pseudomonas Quinolone Signal (PQS). We observed that AmiE overproduction reduced levels of HCN and pyocyanin causing a decreased virulence in different hosts (i.e. Dictyostelium discoideum and Caenorhabditis elegans). This phenotype was further confirmed in a mouse model of acute lung infection, in which AmiE overproduction resulted in an almost fully virulence decrease. Taken together, our data suggest that, in addition to its role in bacterial secondary metabolism, AmiE is involved in P. aeruginosa virulence regulation by modulating pilus synthesis and cell-to-cell communication

The involvement of the ami operon in Pseudomonas aeruginosa virulence regulation and biofilm formation reveals new functions for the amidase AmiE

International audienceWe have previously shown that the C-type Natriuretic Peptide (CNP), a peptide produced by the lung, prevents Pseudomonas aeruginosa biofilm formation. In the present study, we identified AmiC as the bacterial target explaining CNP effects, and we studied the involvement of the aliphatic amidase AmiE in these effects. Comparison of 3D structures of human natriuretic peptide receptors and Pseudomonas proteins revealed that the bacterial protein AmiC shows significant similarity with the human C-type natriuretic peptide receptor (hNPR-C). Recombinant protein AmiC was purified and protein/peptide interactions assessed using MicroScale Thermophoresis. Results showed that both CNP and hNPR-C agonists bind the AmiC protein. The amiC gene belongs to the ami operon. This operon also encodes the aliphatic amidase AmiE which hydrolyses short-chain aliphatic amides to their corresponding organic acids. We investigated AmiE potential alternative functions in P. aeruginosa. We observed that over expression of AmiE protein altered biofilm formation, bacterial motilities and quorum sensing molecules production. Using several infection models, we demonstrated that AmiE overproduction led to a strong decrease in P. aeruginosa virulence both in vitro and in vivo, suggesting that in addition to its carbon-nitrogen metabolic process activities, AmiE would have multiple other functions. We demonstrate that the bacterial protein AmiC is an ortholog of the eukaryotic receptor hNPR-C, acting as a CNP sensor in P. aeruginosa. Our data show that the whole ami operon has new functions in bacteria, allowing to modulate the switch between chronic and acute infection depending on exposition to host factors

The involvement of the ami operon in Pseudomonas aeruginosa virulence regulation and biofilm formation reveals new functions for the amidase AmiE

International audienceWe have previously shown that the C-type Natriuretic Peptide (CNP), a peptide produced by the lung, prevents Pseudomonas aeruginosa biofilm formation. In the present study, we identified AmiC as the bacterial target explaining CNP effects, and we studied the involvement of the aliphatic amidase AmiE in these effects. Comparison of 3D structures of human natriuretic peptide receptors and Pseudomonas proteins revealed that the bacterial protein AmiC shows significant similarity with the human C-type natriuretic peptide receptor (hNPR-C). Recombinant protein AmiC was purified and protein/peptide interactions assessed using MicroScale Thermophoresis. Results showed that both CNP and hNPR-C agonists bind the AmiC protein. The amiC gene belongs to the ami operon. This operon also encodes the aliphatic amidase AmiE which hydrolyses short-chain aliphatic amides to their corresponding organic acids. We investigated AmiE potential alternative functions in P. aeruginosa. We observed that over expression of AmiE protein altered biofilm formation, bacterial motilities and quorum sensing molecules production. Using several infection models, we demonstrated that AmiE overproduction led to a strong decrease in P. aeruginosa virulence both in vitro and in vivo, suggesting that in addition to its carbon-nitrogen metabolic process activities, AmiE would have multiple other functions. We demonstrate that the bacterial protein AmiC is an ortholog of the eukaryotic receptor hNPR-C, acting as a CNP sensor in P. aeruginosa. Our data show that the whole ami operon has new functions in bacteria, allowing to modulate the switch between chronic and acute infection depending on exposition to host factors