The Pseudomonas aeruginosa quorum sensing signal molecule N-(3-oxododecanoyl) homoserine lactone enhances keratinocyte migration and induces Mmp13 gene expression in vitro

Bacteria degrading the quorum-sensing (QS) signal molecule N-hexanoylhomoserine lactone were isolated from a tobacco rhizosphere. Twenty-five isolates degrading this homoserine lactone fell into six groups according to their genomic REP-PCR and rrs PCR-RFLP profiles. Representative strains from each group were identified as members of the genera Pseudomonas, Comamonas, Variovorax and Rhodococcus. All these isolates degraded N-acylhomoserine lactones other than the hexanoic acid derivative, albeit with different specificity and kinetics. One of these isolates, Rhodococcus erythropolis strain W2, was used to quench QS-regulated functions of other microbes. In vitro, W2 strongly interfered with violacein production by Chromobacterium violaceum, and transfer of pathogenicity in Agrobacterium tumefaciens. In planta, R. erythropolis W2 markedly reduced the pathogenicity of Pectobacterium carotovorum subsp. carotovorum in potato tubers. These series of results reveal the diversity of the QS-interfering bacteria in the rhizosphere and demonstrate the validity of targeting QS signal molecules to control pathogens with natural bacterial isolates.

Download Full-text

Azithromycin Inhibits MUC5AC Production Induced by the Pseudomonas aeruginosa Autoinducer N-(3-Oxododecanoyl) Homoserine Lactone in NCI-H292 Cells

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.48.9.3457-3461.2004 ◽

2004 ◽

Vol 48 (9) ◽

pp. 3457-3461 ◽

Cited By ~ 87

Author(s):

Yoshifumi Imamura ◽

Katsunori Yanagihara ◽

Yohei Mizuta ◽

Masafumi Seki ◽

Hideaki Ohno ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Bacterial Infection ◽

Core Protein ◽

Homoserine Lactone ◽

Signal Molecule ◽

Diffuse Panbronchiolitis ◽

Mucin Production ◽

Protein Levels ◽

Extracellular Signal

ABSTRACT The features of chronic airway diseases, including chronic bronchitis, cystic fibrosis, bronchiectasis, and diffuse panbronchiolitis, include chronic bacterial infection and airway obstruction by mucus. Pseudomonas aeruginosa is one of the most common pathogens in chronic lung infection, and quorum-sensing systems contribute to the pathogenesis of this disease. The quorum-sensing signal molecule [N-(3-oxododecanoyl) homoserine lactone (3O-C12-HSL)] not only regulates bacterial virulence but also is associated with the immune response. In this study, we investigated whether 3O-C12-HSL could stimulate the production of a major mucin core protein, MUC5AC. The effect of a macrolide on MUC5AC production was also studied. 3O-C12-HSL induced NCI-H292 cells to express MUC5AC at both the mRNA and the protein levels in time- and dose-dependent manners. A 15-membered macrolide, azithromycin, inhibited MUC5AC production that was activated by 3O-C12-HSL. 3O-C12-HSL induced extracellular signal-regulated kinase (ERK) 1/2 and I-κB phosphorylation in cells, and this induction was suppressed by azithromycin. 3O-C12-HSL-induced MUC5AC production was blocked by the ERK pathway inhibitor PD98059. Our findings suggest that the P. aeruginosa autoinducer 3O-C12-HSL contributes to excessive mucin production in chronic bacterial infection. Azithromycin seems to reduce this mucin production by interfering with intracellular signal transduction.

Download Full-text

Mechanistic analysis of a synthetic inhibitor of the Pseudomonas aeruginosa LasI quorum-sensing signal synthase

Scientific Reports ◽

10.1038/srep16569 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 29

Author(s):

O. Lidor ◽

A. Al-Quntar ◽

E. C. Pesci ◽

D. Steinberg

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

In Silico ◽

Biofilm Formation ◽

Homoserine Lactone ◽

Site Directed Mutagenesis ◽

Great Promise ◽

Acyl Homoserine Lactone ◽

Virulence Determinants

Abstract Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen responsible for many human infections. LasI is an acyl-homoserine lactone synthase that produces a quorum-sensing (QS) signal that positively regulates numerous P. aeruginosa virulence determinants. The inhibition of the LasI protein is therefore an attractive drug target. In this study, a novel in silico to in vitro complementation was applied to screen thiazolidinedione-type compounds for their ability to inhibit biofilm formation at concentrations not affecting bacterial growth. The compound (z)-5-octylidenethiazolidine-2, 4-dione (TZD-C8) was a strong inhibitor of biofilm formation and chosen for further study. Structural exploration of in silico docking predicted that the compound had high affinity for the LasI activity pocket. The TZD-C8 compound was also predicted to create hydrogen bonds with residues Arg30 and Ile107. Site-directed mutagenesis (SDM) of these two sites demonstrated that TZD-C8 inhibition was abolished in the lasI double mutant PAO-R30D, I107S. In addition, in vitro swarming motility and quorum sensing signal production were affected by TZD-C 8, confirming this compound alters the cell to cell signalling circuitry. Overall, this novel inhibitor of P. aeruginosa quorum sensing shows great promise and validates our mechanistic approach to discovering inhibitors of LuxI-type acyl-homoserine lactone synthases.

Download Full-text

ThePseudomonas aeruginosaOrphan Quorum Sensing Signal Receptor QscR Regulates Global Quorum Sensing Gene Expression by Activating a Single Linked Operon

mBio ◽

10.1128/mbio.01274-18 ◽

2018 ◽

Vol 9 (4) ◽

Cited By ~ 15

Author(s):

Fengming Ding ◽

Ken-Ichi Oinuma ◽

Nicole E. Smalley ◽

Amy L. Schaefer ◽

Omar Hamwy ◽

...

Keyword(s):

Gene Expression ◽

Pseudomonas Aeruginosa ◽

Transcription Factor ◽

Quorum Sensing ◽

Cell Communication ◽

Homoserine Lactone ◽

Acyl Homoserine Lactone ◽

Null Mutant ◽

Content Type ◽

Single Operon

ABSTRACTPseudomonas aeruginosauses two acyl-homoserine lactone signals and two quorum sensing (QS) transcription factors, LasR and RhlR, to activate dozens of genes. LasR responds toN-3-oxo-dodecanoyl-homoserine lactone (3OC12-HSL) and RhlR toN-butanoyl-homoserine lactone (C4-HSL). There is a thirdP. aeruginosaacyl-homoserine-lactone-responsive transcription factor, QscR, which acts to dampen or delay activation of genes by LasR and RhlR by an unknown mechanism. To better understand the role of QscR inP. aeruginosaQS, we performed a chromatin immunoprecipitation analysis, which showed this transcription factor bound the promoter of only a single operon of three genes linked toqscR, PA1895 to PA1897. Other genes that appear to be regulated by QscR in transcriptome studies were not direct targets of QscR. Deletion of PA1897 recapitulates the early QS activation phenotype of a QscR-null mutant, and the phenotype of a QscR-null mutant was complemented by PA1895-1897 but not by PA1897 alone. We conclude that QscR acts to modulate quorum sensing through regulation of a single operon, apparently raising the QS threshold of the population and providing a “brake” on QS autoinduction.IMPORTANCEQuorum sensing, a cell-cell communication system, is broadly distributed among bacteria and is commonly used to regulate the production of shared products. An important consequence of quorum sensing is a delay in production of certain products until the population density is high. The bacteriumPseudomonas aeruginosahas a particularly complicated quorum sensing system involving multiple signals and receptors. One of these receptors, QscR, downregulates gene expression, unlike the other receptors inP. aeruginosa. QscR does so by inducing the expression of a single operon whose function provides an element of resistance to a population reaching a quorum. This finding has importance for design of quorum sensing inhibitory strategies and can also inform design of synthetic biological circuits that use quorum sensing receptors to regulate gene expression.

Download Full-text

A Distinct QscR Regulon in the Pseudomonas aeruginosa Quorum-Sensing Circuit

Journal of Bacteriology ◽

10.1128/jb.188.9.3365-3370.2006 ◽

2006 ◽

Vol 188 (9) ◽

pp. 3365-3370 ◽

Cited By ~ 144

Author(s):

Yannick Lequette ◽

Joon-Hee Lee ◽

Fouzia Ledgham ◽

Andrée Lazdunski ◽

E. Peter Greenberg

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Opportunistic Pathogen ◽

Homoserine Lactone ◽

Acyl Homoserine Lactone ◽

Signal Molecule ◽

Control Of Gene Expression ◽

Signaling Systems ◽

Sensing Systems

ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa possesses two complete acyl-homoserine lactone (acyl-HSL) signaling systems. One system consists of LasI and LasR, which generate a 3-oxododecanoyl-homoserine lactone signal and respond to that signal, respectively. The other system is RhlI and RhlR, which generate butanoyl-homoserine lactone and respond to butanoyl-homoserine lactone, respectively. These quorum-sensing systems control hundreds of genes. There is also an orphan LasR-RhlR homolog, QscR, for which there is no cognate acyl-HSL synthetic enzyme. We previously reported that a qscR mutant is hypervirulent and showed that QscR transiently represses a few quorum-sensing-controlled genes. To better understand the role of QscR in P. aeruginosa gene regulation and to better understand the relationship between QscR, LasR, and RhlR control of gene expression, we used transcription profiling to identify a QscR-dependent regulon. Our analysis revealed that QscR activates some genes and represses others. Some of the repressed genes are not regulated by the LasR-I or RhlR-I systems, while others are. The LasI-generated 3-oxododecanoyl-homoserine lactone serves as a signal molecule for QscR. Thus, QscR appears to be an integral component of the P. aeruginosa quorum-sensing circuitry. QscR uses the LasI-generated acyl-homoserine lactone signal and controls a specific regulon that overlaps with the already overlapping LasR- and RhlR-dependent regulons.

Download Full-text

Sub-lethal antimicrobial photodynamic inactivation: an in vitro study on quorum sensing-controlled gene expression of Pseudomonas aeruginosa biofilm formation

Lasers in Medical Science ◽

10.1007/s10103-018-02707-y ◽

2019 ◽

Vol 34 (6) ◽

pp. 1159-1165 ◽

Cited By ~ 4

Author(s):

Saghar Hendiani ◽

Majid Pornour ◽

Nasim Kashef

Keyword(s):

Gene Expression ◽

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Biofilm Formation ◽

In Vitro Study ◽

Vitro Study ◽

Photodynamic Inactivation

Download Full-text

Advancing the Quorum in Pseudomonas aeruginosa: MvaT and the Regulation of N-Acylhomoserine Lactone Production and Virulence Gene Expression

Journal of Bacteriology ◽

10.1128/jb.184.10.2576-2586.2002 ◽

2002 ◽

Vol 184 (10) ◽

pp. 2576-2586 ◽

Cited By ~ 182

Author(s):

Stephen P. Diggle ◽

Klaus Winzer ◽

Andrée Lazdunski ◽

Paul Williams ◽

Miguel Cámara

Keyword(s):

Gene Expression ◽

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Growth Phase ◽

Virulence Gene ◽

Homoserine Lactone ◽

Logarithmic Phase ◽

Signal Molecules ◽

Virulence Gene Expression ◽

Acylhomoserine Lactone

ABSTRACT Pseudomonas aeruginosa regulates the production of many exoproteins and secondary metabolites via a hierarchical quorum-sensing cascade through LasR and RhlR and their cognate signal molecules N-(3-oxododecanoyl)-l-homoserine lactone (3O-C12-HSL) and N-(butanoyl)-l-homoserine lactone (C4-HSL). In this study, we found that transcription of the quorum sensing-regulated genes lecA (coding for PA-IL lectin), lasB (coding for elastase), and rpoS appeared to be growth phase dependent and their expression could not be advanced to the logarithmic phase in cells growing in batch culture by the addition of exogenous C4-HSL and 3O-C12-HSL. To identify novel regulators responsible for this growth phase dependency, a P. aeruginosa lecA::lux reporter strain was subjected to random transposon mutagenesis. A number of mutants affected in lecA expression were found that exhibited altered production of multiple quorum sensing-dependent phenotypes. While some mutations were mapped to new loci such as clpA and mvaT and a putative efflux system, a number of mutations were also mapped to known regulators such as lasR, rhlR, and rpoS. MvaT was identified as a novel global regulator of virulence gene expression, as a mutation in mvaT resulted in enhanced lecA expression and pyocyanin production. This mutant also showed altered swarming ability and production of the LasB and LasA proteases, 3O-C12-HSL, and C4-HSL. Furthermore, addition of exogenous 3O-C12-HSL and C4-HSL to the mvaT mutant significantly advanced lecA expression, suggesting that MvaT is involved in the growth phase-dependent regulation of the lecA gene.

Download Full-text

Identification, Timing, and Signal Specificity of Pseudomonas aeruginosa Quorum-Controlled Genes: a Transcriptome Analysis

Journal of Bacteriology ◽

10.1128/jb.185.7.2066-2079.2003 ◽

2003 ◽

Vol 185 (7) ◽

pp. 2066-2079 ◽

Cited By ~ 703

Author(s):

Martin Schuster ◽

C. Phoebe Lostroh ◽

Tomoo Ogi ◽

E. P. Greenberg

Keyword(s):

Gene Expression ◽

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Stationary Phase ◽

Transcriptome Analysis ◽

Homoserine Lactone ◽

Logarithmic Phase ◽

Acyl Homoserine Lactone ◽

Global Regulators ◽

Signaling Systems

ABSTRACT There are two interrelated acyl-homoserine lactone quorum-sensing-signaling systems in Pseudomonas aeruginosa. These systems, the LasR-LasI system and the RhlR-RhlI system, are global regulators of gene expression. We performed a transcriptome analysis to identify quorum-sensing-controlled genes and to better understand quorum-sensing control of P. aeruginosa gene expression. We compared gene expression in a LasI-RhlI signal mutant grown with added signals to gene expression without added signals, and we compared a LasR-RhlR signal receptor mutant to its parent. In all, we identified 315 quorum-induced and 38 quorum-repressed genes, representing about 6% of the P. aeruginosa genome. The quorum-repressed genes were activated in the stationary phase in quorum-sensing mutants but were not activated in the parent strain. The analysis of quorum-induced genes suggests that the signal specificities are on a continuum and that the timing of gene expression is on a continuum (some genes are induced early in growth, most genes are induced at the transition from the logarithmic phase to the stationary phase, and some genes are induced during the stationary phase). In general, timing was not related to signal concentration. We suggest that the level of the signal receptor, LasR, is a critical trigger for quorum-activated gene expression. Acyl-homoserine lactone quorum sensing appears to be a system that allows ordered expression of hundreds of genes during P. aeruginosa growth in culture.

Download Full-text

Albumin Inhibits Pseudomonas aeruginosa Quorum Sensing and Alters Polymicrobial Interactions

Infection and Immunity ◽

10.1128/iai.00116-17 ◽

2017 ◽

Vol 85 (9) ◽

Cited By ~ 25

Author(s):

Allie Clinton Smith ◽

Anne Rice ◽

Bryan Sutton ◽

Rebecca Gabrilska ◽

Aimee K. Wessel ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Chronic Wounds ◽

Homoserine Lactone ◽

Individual Species ◽

Content Type ◽

The Individual ◽

Chronic Wound Infections ◽

Isolated Species

ABSTRACT Polymicrobial interactions are complex and can influence the course of an infection, as is the case when two or more species exhibit a synergism that produces a disease state not seen with any of the individual species alone. Cell-to-cell signaling is key to many of these interactions, but little is understood about how the host environment influences polymicrobial interactions or signaling between bacteria. Chronic wounds are typically polymicrobial, with Staphylococcus aureus and Pseudomonas aeruginosa being the two most commonly isolated species. While P. aeruginosa readily kills S. aureus in vitro, the two species can coexist for long periods together in chronic wound infections. In this study, we investigated the ability of components of the wound environment to modulate interactions between P. aeruginosa and S. aureus. We demonstrate that P. aeruginosa quorum sensing is inhibited by physiological levels of serum albumin, which appears to bind and sequester some homoserine lactone quorum signals, resulting in the inability of P. aeruginosa to produce virulence factors that kill S. aureus. These data could provide important clues regarding the virulence of P. aeruginosa in albumin-depleted versus albumin-rich infection sites and an understanding of the nature of friendly versus antagonistic interactions between P. aeruginosa and S. aureus.

Download Full-text