Inactivation of the rhlA gene in Pseudomonas aeruginosa prevents rhamnolipid production, disabling the protection against polymorphonuclear leukocytes

  title={Inactivation of the rhlA gene in Pseudomonas aeruginosa prevents rhamnolipid production, disabling the protection against polymorphonuclear leukocytes},
  author={Maria van Gennip and Louise Dahl Christensen and Morten Alhede and Richard Kerry Phipps and Peter {\O}strup Jensen and Lars Jackie Christophersen and S{\"u}nje Johanna Pamp and Claus E Moser and Per Jensen Mikkelsen and Andrew Y. Koh and Tim Tolker-Nielsen and Gerald B. Pier and Niels H{\O}iby and Michael Givskov and Thomas Bjarnsholt},
Many of the virulence factors produced by the opportunistic human pathogen Pseudomonas aeruginosa are quorum‐sensing (QS) regulated. Among these are rhamnolipids, which have been shown to cause lysis of several cellular components of the human immune system, e.g. monocyte‐derived macrophages and polymorphonuclear leukocytes (PMNs). We have previously shown that rhamnolipids produced by P. aeruginosa cause necrotic death of PMNs in vitro. This raises the possibility that rhamnolipids may… 

Pseudomonas aeruginosa‐derived rhamnolipids subvert the host innate immune response through manipulation of the human beta‐defensin‐2 expression

Rhamnolipids can be engaged by P. aeruginosa for a targeted attenuation of the innate immunity to manage its survival and colonization on compromised epithelia to neutralize this pathogen.

Structure‐Function Relationships of Rhamnolipid and Exopolysacharide Biosurfactants of Pseudomonas aeruginosa as Therapeutic Targets in Cystic Fibrosis Lung Infections

In the future, impairment of P. aeruginosa quorum sensing (QS) pathways and modification of host respiratory mucus epithelial membranes should be considered as potential approaches in preventing respiratory infections caused by this microbe in CF patients.

Assessment of the ahyI gene affected biofilm formation, motility, extracellular virulence and the pathogenicity in a fish model of infection

Results suggest that A. hydrophila is able to regulate its extracellular virulent factors and biofilm formation by quorum sensing systems, and indicate that disruption of quorum Sensing could be a good alternative strategy to combat infections caused by A. Hydrophila.

Role of Host and Bacterial Lipids in Pseudomonas aeruginosa Respiratory Infections

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Effects of null mutation of the heat-shock gene htpG on the production of virulence factors by Pseudomonas aeruginosa.

It is shown that ΔhtpG mutant affects many physiological processes containing: decreased activity of the LasA protease, reduction of biofilm formation, decreased motility, and diminished amount of rhamnolipids and pyoverdine/pyocyanin.

Genome-Wide Analysis Reveals a RhlA-Dependent Modulation of Flagellar Genes in Pseudomonas Aeruginosa PAO1

Significant evidence is shown that rhamnolipids and/or their precursors, 3-(3-hydroxyalkanoyloxy) alkanoic acids, the major biosynthetic products of rhlABC pathway, seem to modulate gene expression in P. aeruginosa.

Activity of Cinnamaldehyde on Quorum Sensing and Biofilm Susceptibility to Antibiotics in Pseudomonas aeruginosa

A proposed method to mitigate P. aeruginosa infection is a combination therapy of CAD with COL or CAD with TOB as alternatives to current individual drug therapies.

Impairment of Pseudomonas aeruginosa Biofilm Resistance to Antibiotics by Combining the Drugs with a New Quorum-Sensing Inhibitor

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The Major Outer Membrane Protein Oprf is Required for Rhamnolipid Production in Pseudomonas aeruginosa

The OprF porin is the major outer membrane protein of bacteria belonging to the Pseudomonas genus, and is partially exposed on the cellular surface, making it a serious target for limiting P. aeruginosa spreading in case of cystic fibrosis.



Rapid necrotic killing of polymorphonuclear leukocytes is caused by quorum-sensing-controlled production of rhamnolipid by Pseudomonas aeruginosa.

The results demonstrate the potential of the QS system to facilitate infections with P. aeruginosa by disabling the PMNs, which are a major first line of defence of the host.

Effects of Pseudomonas aeruginosa rhamnolipids on human monocyte‐derived macrophages

A simplified method for the isolation of these rhamnolipids is described and the possible significance of these extracellular bacterial glycolipids as a virulence factor in the pathogenesis of P. aeruginosa is discussed.

Impact of Pseudomonas aeruginosa quorum sensing on biofilm persistence in an in vivo intraperitoneal foreign-body infection model.

The present results support a model by which functional QS systems play a pivotal role in the ability of bacteria to resist clearing by the innate immune system and strongly suggest that the efficiency of the mouse innate defence against biofilm-forming P. aeruginosa is improved when the bacteria are treated with QS drugs that induce QS deficiency.

Rhamnolipid Surfactant Production Affects Biofilm Architecture in Pseudomonas aeruginosa PAO1

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Attenuation of Pseudomonas aeruginosa virulence by quorum sensing inhibitors

A synthetic derivate of natural furanone compounds can act as a potent antagonist of bacterial quorum sensing and inhibited virulence factor expression in a mouse pulmonary infection model.

A second N-acylhomoserine lactone signal produced by Pseudomonas aeruginosa.

The role of factor 2 in virulence gene regulation remains to be determined, but this compound may affect the expression of lasR, which in turn activation of numerous virulence genes in the presence of sufficient PAI.

Overexpression of the MexEF-OprN Multidrug Efflux System Affects Cell-to-Cell Signaling in Pseudomonas aeruginosa

It is reported that nfxC type mutants, overexpressing the MexEF-OprN efflux system, produce lower levels of extracellular virulence factors than the susceptible wild type.

Multiple Roles of Biosurfactants in Structural Biofilm Development by Pseudomonas aeruginosa

Genetic evidence is presented that during biofilm development by P. aeruginosa, biosurfactants promote microcolony formation in the initial phase and facilitate migration-dependent structural development in the later phase of biofilm formation.

Transcriptome analysis of Pseudomonas aeruginosa biofilm development: anaerobic respiration and iron limitation

This study shows that, when compared with planktonic bacteria, gene expression profiles of biofilm cells have the highest resemblance to the profiles of stationary-phase cells, and presents evidence that quorum sensing is participating in the control of iron-limitation responses in theBiofilm cells.

Microbial pathogenesis in cystic fibrosis: mucoid Pseudomonas aeruginosa and Burkholderia cepacia.

This review summarizes the latest advances in understanding host-pathogen interactions in CF with an emphasis on the role and control of conversion to mucoidy in P. aeruginosa and B. cepacia.