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Conaway A, Todorovic I, Mould DL, Hogan DA. Loss of LasR function leads to decreased repression of Pseudomonas aeruginosa PhoB activity at physiological phosphate concentrations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.586856. [PMID: 38585852 PMCID: PMC10996656 DOI: 10.1101/2024.03.27.586856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
While the Pseudomonas aeruginosa LasR transcription factor plays a role in quorum sensing (QS) across phylogenetically-distinct lineages, isolates with loss-of-function mutations in lasR (LasR- strains) are commonly found in diverse settings including infections where they are associated with worse clinical outcomes. In LasR- strains, the transcription factor RhlR, which is controlled by LasR, can be alternately activated in low inorganic phosphate (Pi) concentrations via the two-component system PhoR-PhoB. Here, we demonstrate a new link between LasR and PhoB in which the absence of LasR increases PhoB activity at physiological Pi concentrations and raises the Pi concentration necessary for PhoB inhibition. PhoB activity was also less repressed by Pi in mutants lacking different QS regulators (RhlR and PqsR) and in mutants lacking genes required for the production of QS-regulated phenazines suggesting that decreased phenazine production was one reason for decreased PhoB repression by Pi in LasR- strains. In addition, the CbrA-CbrB two-component system, which is elevated in LasR- strains, was necessary for reduced PhoB repression by Pi and a Δcrc mutant, which lacks the CbrA-CbrB-controlled translational repressor, activated PhoB at higher Pi concentrations than the wild type. The ΔlasR mutant had a PhoB-dependent growth advantage in a medium with no added Pi and increased virulence-determinant gene expression in a medium with physiological Pi, in part through reactivation of QS. This work suggests PhoB activity may contribute to the virulence of LasR- P. aeruginosa and subsequent clinical outcomes.
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Manson DE, Ananiev GE, Guo S, Ericksen SS, Santa EE, Blackwell HE. Abiotic Small Molecule Inhibitors and Activators of the LasR Quorum Sensing Receptor in Pseudomonas aeruginosa with Potencies Comparable or Surpassing N-Acyl Homoserine Lactones. ACS Infect Dis 2024; 10:1212-1221. [PMID: 38506163 PMCID: PMC11014758 DOI: 10.1021/acsinfecdis.3c00593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa controls almost 10% of its genome, including myriad virulence genes, via a cell-to-cell chemical communication system called quorum sensing (QS). Small molecules that either inhibit or activate QS in P. aeruginosa represent useful research tools to study the role of this signaling pathway in infection and interrogate its viability as an antivirulence target. However, despite active research in this area over the past 20+ years, there are relatively few synthetic compounds known to strongly inhibit or activate QS in P. aeruginosa. Most reported QS modulators in this pathogen are of low potency or have structural liabilities that limit their application in biologically relevant environments such as mimics of the native N-acyl l-homoserine lactone (AHL) signals. Here, we report the results of a high-throughput screen for abiotic small molecules that target LasR, a key QS regulator in P. aeruginosa. We screened a 25,000-compound library and discovered four new structural classes of abiotic LasR modulators. These compounds include antagonists that surpass the potency of all known AHL-type compounds and mimetics thereof, along with an agonist with potency approaching that of LasR's native ligand. The novel structures of this compound set, along with their anticipated robust physicochemical profiles, underscore their potential value as probe molecules to interrogate the roles of QS in this formidable pathogen.
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Affiliation(s)
- Daniel E Manson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States
| | - Gene E Ananiev
- Small Molecule Screening Facility, University of Wisconsin Carbone Cancer Center, 600 Highland Ave., Madison, Wisconsin 53792, United States
| | - Song Guo
- Small Molecule Screening Facility, University of Wisconsin Carbone Cancer Center, 600 Highland Ave., Madison, Wisconsin 53792, United States
| | - Spencer S Ericksen
- Small Molecule Screening Facility, University of Wisconsin Carbone Cancer Center, 600 Highland Ave., Madison, Wisconsin 53792, United States
| | - Emma E Santa
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States
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3
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Vadakkan K, Ngangbam AK, Sathishkumar K, Rumjit NP, Cheruvathur MK. A review of chemical signaling pathways in the quorum sensing circuit of Pseudomonas aeruginosa. Int J Biol Macromol 2024; 254:127861. [PMID: 37939761 DOI: 10.1016/j.ijbiomac.2023.127861] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/26/2023] [Accepted: 11/01/2023] [Indexed: 11/10/2023]
Abstract
Pseudomonas aeruginosa, an increasingly common competitive and biofilm organism in healthcare infection with sophisticated, interlinked and hierarchic quorum systems (Las, Rhl, PQS, and IQS), creates the greatest threats to the medical industry and has rendered prevailing chemotherapy medications ineffective. The rise of multidrug resistance has evolved into a concerning and potentially fatal occurrence for human life. P. aeruginosa biofilm development is assisted by exopolysaccharides, extracellular DNA, proteins, macromolecules, cellular signaling and interaction. Quorum sensing is a communication process between cells that involves autonomous inducers and regulators. Quorum-induced infectious agent biofilms and the synthesis of virulence factors have increased disease transmission, medication resistance, infection episodes, hospitalizations and mortality. Hence, quorum sensing may be a potential therapeutical target for bacterial illness, and developing quorum inhibitors as an anti-virulent tool could be a promising treatment strategy for existing antibiotics. Quorum quenching is a prevalent technique for treating infections caused by microbes because it diminishes microbial pathogenesis and increases microbe biofilm sensitivity to antibiotics, making it a potential candidate for drug development. This paper examines P. aeruginosa quorum sensing, the hierarchy of quorum sensing mechanism, quorum sensing inhibition and quorum sensing inhibitory agents as a drug development strategy to supplement traditional antibiotic strategies.
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Affiliation(s)
- Kayeen Vadakkan
- Department of Biology, St. Mary's College, Thrissur, Kerala 680020, India; Manipur International University, Imphal, Manipur 795140, India.
| | | | - Kuppusamy Sathishkumar
- Rhizosphere Biology Laboratory, Department of Microbiology, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620024, India; Department of Computational Biology, Institute of Bioinformatics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Thandalam, Chennai 602 105, Tamil Nadu, India
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Tan X, Cheng X, Xiao J, Liu Q, Du D, Li M, Sun Y, Zhou J, Zhu G. Alkaline phosphatase LapA regulates quorum sensing-mediated virulence and biofilm formation in Pseudomonas aeruginosa PAO1 under phosphate depletion stress. Microbiol Spectr 2023; 11:e0206023. [PMID: 37796007 PMCID: PMC10715133 DOI: 10.1128/spectrum.02060-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/19/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Our previous study demonstrated that the expression of lapA was induced under phosphate depletion conditions, but its roles in virulence and biofilm formation by Pseudomonas aeruginosa remain largely unknown. This study presents a systematic investigation of the roles of lapA in virulence induction and biofilm formation by constructing a lapA-deficient strain with P. aeruginosa PAO1. The results showed that deletion of the lapA gene evidently reduced elastase activity, swimming motility, C4-HSL, and 3-oxo-C12-HSL production, and increased rhamnolipid production under phosphate depletion stress. Moreover, lapA gene deletion inhibited PAO1 biofilm formation in porcine skin explants by reducing the expression levels of las and rhl quorum sensing systems and extracellular polymeric substance synthesis. Finally, lapA gene deletion also reduced the virulence of PAO1 in Caenorhabditis elegans in fast-kill and slow-kill infection assays. This study provides insights into the roles of lapA in modulating P. aeruginosa virulence and biofilm formation under phosphate depletion stress.
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Affiliation(s)
- Xiaojuan Tan
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Xi Cheng
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Jingjing Xiao
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Qianqian Liu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Dongsheng Du
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Minghui Li
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Yang Sun
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Jinwei Zhou
- School of Food and Biology Engineering, Xuzhou University of Technology, Xuzhou, Jiangsu, China
| | - Guoping Zhu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
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5
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Abisado-Duque RG, Townsend KA, Mckee BM, Woods K, Koirala P, Holder AJ, Craddock VD, Cabeen M, Chandler JR. An Amino Acid Substitution in Elongation Factor EF-G1A Alters the Antibiotic Susceptibility of Pseudomonas aeruginosa LasR-Null Mutants. J Bacteriol 2023; 205:e0011423. [PMID: 37191503 PMCID: PMC10294626 DOI: 10.1128/jb.00114-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 04/22/2023] [Indexed: 05/17/2023] Open
Abstract
The opportunistic bacterium Pseudomonas aeruginosa uses the LasR-I quorum-sensing system to increase resistance to the aminoglycoside antibiotic tobramycin. Paradoxically, lasR-null mutants are commonly isolated from chronic human infections treated with tobramycin, suggesting there may be a mechanism that permits the emergence of lasR-null mutants under tobramycin selection. We hypothesized that some other genetic mutations that emerge in these isolates might modulate the effects of lasR-null mutations on antibiotic resistance. To test this hypothesis, we inactivated lasR in several highly tobramycin-resistant isolates from long-term evolution experiments. In some of these isolates, inactivating lasR further increased resistance, compared with decreasing resistance of the wild-type ancestor. These strain-dependent effects were due to a G61A nucleotide polymorphism in the fusA1 gene encoding amino acid substitution A21T in the translation elongation factor EF-G1A. The EF-G1A mutational effects required the MexXY efflux pump and the MexXY regulator ArmZ. The fusA1 mutation also modulated ΔlasR mutant resistance to two other antibiotics, ciprofloxacin and ceftazidime. Our results identify a gene mutation that can reverse the direction of the antibiotic selection of lasR mutants, a phenomenon known as sign epistasis, and provide a possible explanation for the emergence of lasR-null mutants in clinical isolates. IMPORTANCE One of the most common mutations in Pseudomonas aeruginosa clinical isolates is in the quorum sensing lasR gene. In laboratory strains, lasR disruption decreases resistance to the clinical antibiotic tobramycin. To understand how lasR mutations emerge in tobramycin-treated patients, we mutated lasR in highly tobramycin-resistant laboratory strains and determined the effects on resistance. Disrupting lasR enhanced the resistance of some strains. These strains had a single amino acid substitution in the translation factor EF-G1A. The EF-G1A mutation reversed the selective effects of tobramycin on lasR mutants. These results illustrate how adaptive mutations can lead to the emergence of new traits in a population and are relevant to understanding how genetic diversity contributes to the progression of disease during chronic infections.
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Affiliation(s)
| | - Kade A. Townsend
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Brielle M. Mckee
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Kathryn Woods
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Pratik Koirala
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Alexandra J. Holder
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Vaughn D. Craddock
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Matthew Cabeen
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
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6
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Zhang P, Chen W, Ma YC, Bai B, Sun G, Zhang S, Chang X, Wang Y, Jiang N, Zhang X, Ma S. Design and Synthesis of 4-Fluorophenyl-5-methylene-2(5 H)-furanone Derivatives as Potent Quorum Sensing Inhibitors. J Med Chem 2023. [PMID: 37310919 DOI: 10.1021/acs.jmedchem.2c01866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Quorum sensing inhibitors (QSIs) are a class of compounds that can reduce the pathogenicity of bacteria without affecting bacterial growth. In this study, we designed and synthesized four series of 4-fluorophenyl-5-methylene-2(5H)-furanone derivatives and evaluated their QSI activities. Among them, compound 23e not only showed excellent inhibitory activity against various virulence factors but also significantly enhanced the inhibitory activity of antibiotics ciprofloxacin and clarithromycin against two strains of Pseudomonas aeruginosa in vitro. What is even more exciting is that it remarkably increased the antibacterial effect in vivo in combination with ciprofloxacin in the bacteremia model infected with P. aeruginosa PAO1. Moreover, 23e had little hemolytic activity to mouse erythrocytes. Further, the results of GFP reporter fluorescence strain inhibition and β-galactosidase activity inhibition experiments demonstrated that 23e simultaneously targeted the three quorum sensing systems in P. aeruginosa. As a result, compound 23e could be used as an effective QSI for further development against bacterial infections.
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Affiliation(s)
- Panpan Zhang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Weijin Chen
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Yang-Chun Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Bingfang Bai
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Guanglin Sun
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Shenyan Zhang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Xiaohong Chang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Yingmei Wang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Nan Jiang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Xianghui Zhang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
| | - Shutao Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan 250012, China
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7
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Al-Momani H, Almasri M, Al Balawi D, Hamed S, Albiss BA, Aldabaibeh N, Ibrahim L, Albalawi H, Al Haj Mahmoud S, Khasawneh AI, Kilani M, Aldhafeeri M, Bani-Hani M, Wilcox M, Pearson J, Ward C. The efficacy of biosynthesized silver nanoparticles against Pseudomonas aeruginosa isolates from cystic fibrosis patients. Sci Rep 2023; 13:8876. [PMID: 37264060 DOI: 10.1038/s41598-023-35919-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/25/2023] [Indexed: 06/03/2023] Open
Abstract
The high antibiotic resistance of Pseudomonas aeruginosa (PA) makes it critical to develop alternative antimicrobial agents that are effective and affordable. One of the many applications of silver nanoparticles (Ag NPs) is their use as an antimicrobial agent against bacteria resistant to common antibiotics. The key purpose of this research was to assess the antibacterial and antibiofilm effectiveness of biosynthesized Ag NPs against six biofilm-forming clinically isolated strains of PA and one reference strain (ATCC 27853). Ag NPs were biosynthesized using a seed extract of Peganum harmala as a reducing agent. Ag NPs were characterized by Ultraviolet-visible (UV-Vis) spectroscopy and scanning transmission electron microscopy (STEM). The effect of Ag NPs on biofilm formation and eradication was examined through micro-titer plate assays, and the minimal inhibitory (MIC) and minimum bactericidal (MBC) concentrations determined. In addition, real-time polymerase chain reactions (RT-PCR) were performed to examine the effects of Ag NPs on the expression of seven PA biofilm-encoding genes (LasR, LasI, LssB, rhIR, rhII, pqsA and pqsR). The biosynthesized Ag NPs were spherically-shaped with a mean diameter of 11 nm. The MIC for each PA strain was 15.6 µg/ml, while the MBC was 31.25 µg/ml. All PA strains exposed to Ag NPs at sub-inhibitory concentrations (0.22-7.5 µg/ml) showed significant inhibitory effects on growth and biofilm formation. Biomass and biofilm metabolism were reduced dependent on Ag NP concentration. The expression of the quorum-sensing genes of all strains were significantly reduced at an Ag NP concentration of 7.5 µg/ml. The results demonstrate the extensive in-vitro antibacterial and antibiofilm performance of Ag NPs and their potential in the treatment of PA infection. It is recommended that future studies examine the possible synergy between Ag NPs and antibiotics.
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Affiliation(s)
- Hafez Al-Momani
- Department of Microbiology, Pathology and Forensic Medicine, Faculty of Medicine, Hashemite University Medical School, The Hashemite University, Zarqa, 13133, Jordan.
| | - Muna Almasri
- Faculty of Applied Medical Sciences, The Hashemite University, Zarqa, 13133, Jordan
| | - Dua'A Al Balawi
- Faculty of Applied Medical Sciences, The Hashemite University, Zarqa, 13133, Jordan
| | - Saja Hamed
- Department of Pharmaceutical and Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, The Hashemite University, Zarqa, Jordan
| | - Borhan Aldeen Albiss
- Nanotechnology Institute, Jordan University of Science & Technology, P.O. Box 3030, Irbid, 22110, Jordan
| | - Nour Aldabaibeh
- Supervisor of Microbiology Laboratory, Laboratory Medicine Department, Jordan University Hospital, Amman, Jordan
| | - Lugain Ibrahim
- Faculty of Applied Medical Sciences, The Hashemite University, Zarqa, 13133, Jordan
| | - Hadeel Albalawi
- Faculty of Applied Medical Sciences, The Hashemite University, Zarqa, 13133, Jordan
| | - Sameer Al Haj Mahmoud
- Department of Basic Medical Science, Faculty of Medicine, Al-Balqa' Applied University, AL-Salt, Jordan
| | - Ashraf I Khasawneh
- Department of Microbiology, Pathology and Forensic Medicine, Faculty of Medicine, Hashemite University Medical School, The Hashemite University, Zarqa, 13133, Jordan
| | - Muna Kilani
- Department of Pediatrics, Faculty of Medicine, The Hashemite University, Zarqa, Jordan
| | - Muneef Aldhafeeri
- Biosciences Institute, Medical School, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK
| | - Muayyad Bani-Hani
- Department of Plant Production and Protection, Faculty of Agriculture, Jerash University, Jerash, Jordan
| | - Matthew Wilcox
- Institutes of Cellular Medicine and Cell & Molecular Biosciences, Newcastle University Medical School, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK
- Biosciences Institute, Medical School, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK
| | - Jeffrey Pearson
- Biosciences Institute, Medical School, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK
| | - Christopher Ward
- Institutes of Cellular Medicine and Cell & Molecular Biosciences, Newcastle University Medical School, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK
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Singh VK, Almpani M, Wheeler KM, Rahme LG. Interconnections of Pseudomonas aeruginosa Quorum-Sensing Systems in Intestinal Permeability and Inflammation. mBio 2023; 14:e0352422. [PMID: 36786582 PMCID: PMC10127598 DOI: 10.1128/mbio.03524-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 01/21/2023] [Indexed: 02/15/2023] Open
Abstract
Quorum sensing (QS) is a highly conserved microbial communication mechanism based on the production and sensing of secreted signaling molecules. The recalcitrant pathogen Pseudomonas aeruginosa is a problematic nosocomial pathogen with complex interconnected QS systems controlling multiple virulence functions. The relevance of QS in P. aeruginosa pathogenesis is well established; however, the regulatory interrelationships of the three major QS systems, LasR/LasI, MvfR (PqsR)/PqsABCD, and RhlR/RhlI, have been studied primarily in vitro. It is, therefore, unclear how these relationships translate to the host environment during infection. Here, we use a collection of P. aeruginosa QS mutants of the three major QS systems to assess the interconnections and contributions in intestinal inflammation and barrier function in vivo. This work reveals that MvfR, not LasR or RhlR, promotes intestinal inflammation during infection. In contrast, we find that P. aeruginosa-driven murine intestinal permeability is controlled by an interconnected QS network involving all three regulators, with MvfR situated upstream of LasR and RhlR. This study demonstrates the importance of understanding the interrelationships of the QS systems during infection and provides critical insights for developing successful antivirulence strategies. Moreover, this work provides a framework to interrogate QS systems in physiologically relevant settings. IMPORTANCE Pseudomonas aeruginosa is a common multidrug-resistant bacterial pathogen that seriously threatens critically ill and immunocompromised patients. Intestinal colonization by this pathogen is associated with elevated mortality rates. Disrupting bacterial communication is a desirable anti-infective approach since these systems coordinate multiple acute and chronic virulence functions in P. aeruginosa. Here, we investigate the role of each of the three major communication systems in the host intestinal functions. This work reveals that P. aeruginosa influences intestinal inflammation and permeability through distinct mechanisms.
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Affiliation(s)
- Vijay K. Singh
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Shriners Hospitals for Children, Boston, Massachusetts, USA
| | - Marianna Almpani
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Shriners Hospitals for Children, Boston, Massachusetts, USA
| | - Kelsey M. Wheeler
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Laurence G. Rahme
- Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Shriners Hospitals for Children, Boston, Massachusetts, USA
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9
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Abisado-Duquea RG, McKee BM, Townsend KA, Woods K, Koirala P, Holder AJ, Craddock VD, Cabeen MT, Chandler JR. Tobramycin adaptation alters the antibiotic susceptibility of Pseudomonas aeruginosa quorum sensing-null mutants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523864. [PMID: 36711731 PMCID: PMC9882136 DOI: 10.1101/2023.01.13.523864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The opportunistic bacterium Pseudomonas aeruginosa uses the LasR-I quorum sensing system to increase resistance to the aminioglycoside antibiotic tobramycin. Paradoxically, lasR-null mutants are commonly isolated from chronic human infections treated with tobramycin, suggesting there may be a mechanism allowing the lasR-null mutants to persist under tobramycin selection. We hypothesized that the effects of inactivating lasR on tobramycin resistance might be dependent on the presence or absence of other gene mutations in that strain, a phenomenon known as epistasis. To test this hypothesis, we inactivated lasR in several highly tobramycin-resistant isolates from long-term evolution experiments. We show that the effects of ΔlasR on tobramycin resistance are strain dependent. The effects can be attributed to a point mutation in the gene encoding the translation elongation factor fusA1 (G61A nucleotide substitution), which confers a strong selective advantage to lasR-null PA14 under tobramycin selection. This fusA1 G61A mutation results in increased activity of the MexXY efflux pump and expression of the mexXY regulator ArmZ. The fusA1 mutation can also modulate ΔlasR mutant resistance to two other antibiotics, ciprofloxacin and ceftazidime. Our results demonstrate the importance of epistatic gene interactions on antibiotic susceptibility of lasR-null mutants. These results support of the idea that gene interactions might play a significant role in the evolution of quorum sensing in P. aeruginosa.
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10
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Beenker WAG, Hoeksma J, Bannier-Hélaouët M, Clevers H, den Hertog J. Paecilomycone Inhibits Quorum Sensing in Gram-Negative Bacteria. Microbiol Spectr 2023; 11:e0509722. [PMID: 36920212 PMCID: PMC10100902 DOI: 10.1128/spectrum.05097-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/20/2023] [Indexed: 03/16/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes major health care concerns due to its virulence and high intrinsic resistance to antimicrobial agents. Therefore, new treatments are greatly needed. An interesting approach is to target quorum sensing (QS). QS regulates the production of a wide variety of virulence factors and biofilm formation in P. aeruginosa. This study describes the identification of paecilomycone as an inhibitor of QS in both Chromobacterium violaceum and P. aeruginosa. Paecilomycone strongly inhibited the production of virulence factors in P. aeruginosa, including various phenazines, and biofilm formation. In search of the working mechanism, we found that paecilomycone inhibited the production of 4-hydroxy-2-heptylquinoline (HHQ) and 3,4-dihydroxy-2-heptylquinoline (PQS), but not 2'-aminoacetophenone (2-AA). Therefore, we suggest that paecilomycone affects parts of QS in P. aeruginosa by targeting the PqsBC complex and alternative targets or alters processes that influence the enzymatic activity of the PqsBC complex. The toxicity of paecilomycone toward eukaryotic cells and organisms was low, making it an interesting lead for further clinical research. IMPORTANCE Antibiotics are becoming less effective against bacterial infections due to the evolution of resistance among bacteria. Pseudomonas aeruginosa is a Gram-negative pathogen that causes major health care concerns and is difficult to treat due to its high intrinsic resistance to antimicrobial agents. Therefore, new targets are needed, and an interesting approach is to target quorum sensing (QS). QS is the communication system in bacteria that regulates multiple pathways, including the production of virulence factors and biofilm formation, which leads to high toxicity in the host and low sensitivity to antibiotics, respectively. We found a compound, named paecilomycone, that inhibited biofilm formation and the production of various virulence factors in P. aeruginosa. The toxicity of paecilomycone toward eukaryotic cells and organisms was low, making it an interesting lead for further clinical research.
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Affiliation(s)
- Wouter A. G. Beenker
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jelmer Hoeksma
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marie Bannier-Hélaouët
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center, Utrecht, The Netherlands
| | - Hans Clevers
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center, Utrecht, The Netherlands
| | - Jeroen den Hertog
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
- Institute Biology Leiden, Leiden University, Leiden, The Netherlands
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Lima EMF, Almeida FAD, Sircili MP, Bueris V, Pinto UM. N-acetylcysteine (NAC) attenuates quorum sensing regulated phenotypes in Pseudomonas aeruginosa PAO1. Heliyon 2023; 9:e14152. [PMID: 36923901 PMCID: PMC10009464 DOI: 10.1016/j.heliyon.2023.e14152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023] Open
Abstract
The expression of many virulence genes in bacteria is regulated by quorum sensing (QS), and the inhibition of this mechanism has been intensely investigated. N-acetylcysteine (NAC) has good antibacterial activity and is able to interfere with biofilm-related respiratory infections, but little is known whether this compound has an effect on bacterial QS communication. This work aimed to evaluate the potential of NAC as a QS inhibitor (QSI) in Pseudomonas aeruginosa PAO1 through in silico and in vitro analyses, as well as in combination with the antibiotic tobramycin. Initially, a molecular docking analysis was performed between the QS regulatory proteins, LasR and RhlR, of P. aeruginosa with NAC, 3-oxo-C12-HSL, C4-HSL, and furanone C30. The NAC sub-inhibitory concentration was determined by growth curves. Then, we performed in vitro tests using the QS reporter strains P. aeruginosa lasB-gfp and rhlA-gfp, as well as the expression of QS-related phenotypes. Finally, the synergistic effect of NAC with the antibiotic tobramycin was calculated by fractional inhibitory concentrations index (FICi) and investigated against bacterial growth, pigment production, and biofilm formation. In the molecular docking study, NAC bound to LasR and RhlR proteins in a similar manner to the AHL cognate, suggesting that it may be able to bind to QS receptor proteins in vivo. In the biosensor assay, the GFP signal was turned down in the presence of NAC at 1000, 500, 250, and 125 μM for lasB-gfp and rhlA-gfp (p < 0.05), suggesting a QS inhibitory effect. Pyocyanin and rhamnolipids decreased (p < 0.05) up to 34 and 37%, respectively, in the presence of NAC at 125 μM. Swarming and swimming motilities were inhibited (p < 0.05) by NAC at 250 to 10000 μM. Additionally, 2500 and 10000 μM of NAC reduced biofilm formation. NAC-tobramycin combination showed synergistic effect with FICi of 0.8, and the best combination was 2500-1.07 μM, inhibiting biofilm formation up to 60%, besides reducing pyocyanin and pyoverdine production. Confocal microscopy images revealed a stronger, dense, and compact biofilm of P. aeruginosa PAO1 control, while the biofilm treated with NAC-tobramycin became thinner and more dispersed. Overall, NAC at low concentrations showed promising anti-QS properties against P. aeruginosa PAO1, adding to its already known effect as an antibacterial and antibiofilm agent.
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Affiliation(s)
- Emília Maria França Lima
- Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo (USP), São Paulo, SP, Brazil
| | - Felipe Alves de Almeida
- Instituto de Laticínios Cândido Tostes (ILCT), Empresa de Pesquisa Agropecuária de Minas Gerais (EPAMIG), Juiz de Fora, MG, Brazil
| | | | - Vanessa Bueris
- Microbiology Department, Institute of Biomedical Science, University of São Paulo (USP), São Paulo, SP, Brazil
| | - Uelinton Manoel Pinto
- Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo (USP), São Paulo, SP, Brazil
- Corresponding author.
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12
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Gahan CG, Van Lehn RC, Blackwell HE, Lynn DM. Interactions of Bacterial Quorum Sensing Signals with Model Lipid Membranes: Influence of Membrane Composition on Membrane Remodeling. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:295-307. [PMID: 36534123 PMCID: PMC10038191 DOI: 10.1021/acs.langmuir.2c02506] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
We report the influence of membrane composition on the multiscale remodeling of multicomponent lipid bilayers initiated by contact with the amphiphilic bacterial quorum sensing signal N-(3-oxo)-dodecanoyl-l-homoserine lactone (3-oxo-C12-AHL) and its anionic headgroup hydrolysis product, 3-oxo-C12-HS. We used fluorescence microscopy and quartz crystal microbalance with dissipation (QCM-D) to characterize membrane reformation that occurs when these amphiphiles are placed in contact with supported lipid bilayers (SLBs) composed of (i) 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) containing varying amounts of cholesterol or (ii) mixtures of DOPC and either 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE, a conical zwitterionic lipid) or 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS, a model anionic lipid). In general, we observe these mixed-lipid membranes to undergo remodeling events, including the formation and subsequent collapse of long tubules and the formation of hemispherical caps, upon introduction to biologically relevant concentrations of 3-oxo-C12-AHL and 3-oxo-C12-HS in ways that differ substantially from those observed in single-component DOPC membranes. These differences in bilayer reformation and their associated dynamics can be understood in terms of the influence of membrane composition on the time scales of molecular flip-flop, lipid packing defects, and lipid phase segregation in these materials. The lipid components investigated here are representative of classes of lipids that comprise both naturally occurring cell membranes and many useful synthetic soft materials. These studies thus represent a first step toward understanding the ways in which membrane composition can impact interactions with this important class of bacterial signaling molecules.
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Affiliation(s)
- Curran G. Gahan
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, 1415 Engineering Dr., Madison, WI 53706, USA
| | - Reid C. Van Lehn
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, 1415 Engineering Dr., Madison, WI 53706, USA
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706, USA
| | - David M. Lynn
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, 1415 Engineering Dr., Madison, WI 53706, USA
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706, USA
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13
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Kasthuri T, Barath S, Nandhakumar M, Karutha Pandian S. Proteomic profiling spotlights the molecular targets and the impact of the natural antivirulent umbelliferone on stress response, virulence factors, and the quorum sensing network of Pseudomonas aeruginosa. Front Cell Infect Microbiol 2022; 12:998540. [PMID: 36530435 PMCID: PMC9748083 DOI: 10.3389/fcimb.2022.998540] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/18/2022] [Indexed: 12/05/2022] Open
Abstract
Pseudomonas aeruginosa easily adapts to newer environments and acquires several genome flexibilities to overcome the effect of antibiotics during therapeutics, especially in cystic fibrosis patients. During adaptation to the host system, the bacteria employ various tactics including virulence factor production and biofilm formation to escape from the host immune system and resist antibiotics. Hence, identifying alternative strategies to combat recalcitrant pathogens is imperative for the successful elimination of drug-resistant microbes. In this context, this study portrays the anti-virulence efficacy of umbelliferone (UMB) against P. aeruginosa. UMB (7-hydroxy coumarin) is pervasively found among the plant family of Umbelliferae and Asteraceae. The UMB impeded biofilm formation in the P. aeruginosa reference strain and clinical isolates on polystyrene and glass surfaces at the concentration of 125 µg/ml. Global proteomic analysis of UMB-treated cells revealed the downregulation of major virulence-associated proteins such as RhlR, LasA, AlgL, FliD, Tpx, HtpG, KatA, FusA1, Tsf, PhzM, PhzB2, CarB, DctP, MtnA, and MscL. A functional interaction study, gene ontology, and KEGG pathway analysis revealed that UMB could modulate the global regulators, enzymes, co-factors, and transcription factors related to quorum sensing (QS), stress tolerance, siderophore production, motility, and microcolony formation. In vitro biochemical assays further affirmed the anti-virulence efficacy of UMB by reducing pyocyanin, protease, elastase, and catalase production in various strains of P. aeruginosa. Besides the antibiofilm activity, UMB-treated cells exhibited enhanced antibiotic susceptibility to various antibiotics including amikacin, kanamycin, tobramycin, ciprofloxacin, and cefotaxime. Furthermore, in vitro cytotoxicity analysis revealed the biocompatibility of UMB, and the IC50 value was determined to be 249.85 µg/ml on the HepG2 cell line. Altogether, the study substantiates the anti-virulence efficacy of UMB against P. aeruginosa, and the proteomic analysis reveals the differential expression of the regulators related to QS, stress response, and motility factors.
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14
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Nyffeler KE, Santa EE, Blackwell HE. Small Molecules with Either Receptor-Selective or Pan-Receptor Activity in the Three LuxR-Type Receptors that Regulate Quorum Sensing in Pseudomonas aeruginosa. ACS Chem Biol 2022; 17:2979-2985. [PMID: 36239990 PMCID: PMC9675725 DOI: 10.1021/acschembio.2c00675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Quorum sensing (QS) allows bacteria to assess their local cell density using chemical signals and plays a prominent role in the ability of common pathogens to infect a host. Non-native molecules capable of attenuating bacterial QS represent useful tools to explore the role of this pathway in virulence. As individual bacterial species can have multiple QS systems and/or reside in mixed communities with other bacteria capable of QS, chemical tools that are either selective for one QS system or "pan-active" and target all QS pathways are of significant interest. Herein we outline the analysis of a set of compounds reported to target one QS system in Pseudomonas aeruginosa for their activity in two other QS circuits in this pathogen and the discovery of molecules with novel activity profiles, including subsets that agonize all three QS systems, agonize one but antagonize the other two, or strongly antagonize just one.
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Affiliation(s)
- Kayleigh E. Nyffeler
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706, USA,Microbiology Doctoral Training Program, University of Wisconsin–Madison, 1550 Linden Dr., Madison, WI 53706, USA
| | - Emma E. Santa
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706, USA
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15
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Beenker WAG, Hoeksma J, den Hertog J. Gregatins, a Group of Related Fungal Secondary Metabolites, Inhibit Aspects of Quorum Sensing in Gram-Negative Bacteria. Front Microbiol 2022; 13:934235. [PMID: 35865924 PMCID: PMC9296082 DOI: 10.3389/fmicb.2022.934235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/02/2022] [Indexed: 12/11/2022] Open
Abstract
Quorum sensing (QS) is a process that regulates gene expression based on cell density. In bacteria, QS facilitates collaboration and controls a large number of pathways, including biofilm formation and virulence factor production, which lead to lower sensitivity to antibiotics and higher toxicity in the host, respectively. Inhibition of QS is a promising strategy to combat bacterial infections. In this study, we tested the potential of secondary metabolites from fungi to inhibit bacterial QS using a library derived from more than ten thousand different fungal strains. We used the reporter bacterium, Chromobacterium violaceum, and identified 39 fungal strains that produced QS inhibitor activity. These strains expressed two QS inhibitors that had been described before and eight QS inhibitors that had not been described before. Further testing for QS inhibitor activity against the opportunistic pathogen Pseudomonas aeruginosa led to the identification of gregatins as an interesting family of compounds with QS inhibitor activity. Although various gregatins inhibited QS in P. aeruginosa, these gregatins did not inhibit virulence factor production and biofilm formation. We conclude that gregatins inhibit some, but not all aspects of QS.
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Affiliation(s)
- Wouter A. G. Beenker
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, Netherlands
| | - Jelmer Hoeksma
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, Netherlands
| | - Jeroen den Hertog
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, Netherlands
- Institute Biology Leiden, Leiden University, Leiden, Netherlands
- *Correspondence: Jeroen den Hertog
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16
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Biofilm production: A strategic mechanism for survival of microbes under stress conditions. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2022. [DOI: 10.1016/j.bcab.2022.102337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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17
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Polaske TJ, Gahan CG, Nyffeler KE, Lynn DM, Blackwell HE. Identification of small molecules that strongly inhibit bacterial quorum sensing using a high-throughput lipid vesicle lysis assay. Cell Chem Biol 2021; 29:605-614.e4. [PMID: 34932995 PMCID: PMC9035047 DOI: 10.1016/j.chembiol.2021.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/27/2021] [Accepted: 11/29/2021] [Indexed: 01/15/2023]
Abstract
Strategies to both monitor and block bacterial quorum sensing (QS), and thus associated infections, are of significant interest. We developed a straightforward assay to monitor biosurfactants and lytic agents produced by bacteria under the control of QS. The method is based on the lysis of synthetic lipid vesicles containing the environmentally sensitive fluorescent dye calcein. This assay allows for the in situ screening of compounds capable of altering biosurfactant production by bacteria, and thereby the identification of molecules that could potentially modulate QS pathways, and avoids the constraints of many of the cell-based assays in use today. Application of this assay in a high-throughput format revealed five molecules capable of blocking vesicle lysis by S. aureus. Two of these compounds were found to almost completely inhibit agr-based QS in S. aureus and represent the most potent small-molecule-derived QS inhibitors reported in this formidable pathogen.
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Affiliation(s)
- Thomas J Polaske
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Curran G Gahan
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706, USA
| | - Kayleigh E Nyffeler
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA; Microbiology Doctoral Training Program, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706, USA
| | - David M Lynn
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA; Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706, USA.
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA.
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18
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Ruiz CH, Osorio-Llanes E, Trespalacios MH, Mendoza-Torres E, Rosales W, Gómez CMM. Quorum Sensing Regulation as a Target for Antimicrobial Therapy. Mini Rev Med Chem 2021; 22:848-864. [PMID: 34856897 DOI: 10.2174/1389557521666211202115259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 05/20/2021] [Accepted: 09/04/2021] [Indexed: 11/22/2022]
Abstract
Some bacterial species use a cell-to-cell communication mechanism called Quorum Sensing (QS). Bacteria release small diffusible molecules, usually termed signals which allow the activation of beneficial phenotypes that guarantee bacterial survival and the expression of a diversity of virulence genes in response to an increase in population density. The study of the molecular mechanisms that relate signal molecules with bacterial pathogenesis is an area of growing interest due to its use as a possible therapeutic alternative through the development of synthetic analogues of autoinducers as a strategy to regulate bacterial communication as well as the study of bacterial resistance phenomena, the study of these relationships is based on the structural diversity of natural or synthetic autoinducers and their ability to inhibit bacterial QS, which can be approached with a molecular perspective from the following topics: i) Molecular signals and their role in QS regulation; ii) Strategies in the modulation of Quorum Sensing; iii) Analysis of Bacterial QS circuit regulation strategies; iv) Structural evolution of natural and synthetic autoinducers as QS regulators. This mini-review allows a molecular view of the QS systems, showing a perspective on the importance of the molecular diversity of autoinducer analogs as a strategy for the design of new antimicrobial agents.
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Affiliation(s)
- Caterine Henríquez Ruiz
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
| | - Estefanie Osorio-Llanes
- Faculty of Exact and Natural sciences. Grupo de Investigación Avanzada en Biomedicina. Universidad Libre. Barranquilla. Colombia
| | - Mayra Hernández Trespalacios
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
| | - Evelyn Mendoza-Torres
- Faculty of Health Sciences. Grupo de Investigación Avanzada en Biomedicina-Universidad Libre. Barranquilla. Colombia
| | - Wendy Rosales
- Faculty of Exact and Natural sciences. Grupo de Investigación Avanzada en Biomedicina. Universidad Libre. Barranquilla. Colombia
| | - Carlos Mario Meléndez Gómez
- Grupo de Investigación en Química Orgánica y Biomédica. Faculty of Basic Sciences. Universidad del Atlántico. Barranquilla. Colombia
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19
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Soukarieh F, Mashabi A, Richardson W, Oton EV, Romero M, Roberston SN, Grossman S, Sou T, Liu R, Halliday N, Kukavica-Ibrulj I, Levesque RC, Bergstrom CAS, Kellam B, Emsley J, Heeb S, Williams P, Stocks MJ, Cámara M. Design and Evaluation of New Quinazolin-4(3 H)-one Derived PqsR Antagonists as Quorum Sensing Quenchers in Pseudomonas aeruginosa. ACS Infect Dis 2021; 7:2666-2685. [PMID: 34503335 DOI: 10.1021/acsinfecdis.1c00175] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
P. aeruginosa (PA) continues to pose a threat to global public health due to its high levels of antimicrobial resistance (AMR). The ongoing AMR crisis has led to an alarming shortage of effective treatments for resistant microbes, and hence there is a pressing demand for the development of novel antimicrobial interventions. The potential use of antivirulence therapeutics to tackle bacterial infections has attracted considerable attention over the past decades as they hamper the pathogenicity of target microbes with reduced selective pressure, minimizing the emergence of resistance. One such approach is to interfere with the PA pqs quorum sensing system which upon the interaction of PqsR, a Lys-R type transcriptional regulator, with its cognate signal molecules 4-hydroxy-2-heptylquinoline (HHQ) and 2-heptyl-3-hydroxy-4-quinolone (PQS), governs multiple virulence traits and host-microbe interactions. In this study, we report the hit identification and optimization of PqsR antagonists using virtual screening coupled with whole cell assay validation. The optimized hit compound 61 ((R)-2-(4-(3-(6-chloro-4-oxoquinazolin-3(4H)-yl)-2-hydroxypropoxy)phenyl)acetonitrile) was found to inhibit the expression of the PA PpqsA promoter controlled by PqsR with an IC50 of 1 μM. Using isothermal titration calorimetry, a Kd of 10 nM for the PqsR ligand binding domain (PqsRLBD) was determined for 61. Furthermore, the crystal structure of 61 with PqsRLBD was attained with a resolution of 2.65 Å. Compound 61 significantly reduced levels of pyocyanin, PQS, and HHQ in PAO1-L, PA14 lab strains and PAK6085 clinical isolate. Furthermore, this compound potentiated the effect of ciprofloxacin in early stages of biofilm treatment and in Galleria mellonella infected with PA. Altogether, this data shows 61 as a potent PqsR inhibitor with potential for hit to lead optimization toward the identification of a PA QS inhibitor which can be advanced into preclinical development.
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Affiliation(s)
- Fadi Soukarieh
- School of Life Sciences, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
- The National Biofilms Innovation Centre, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Alaa Mashabi
- School of Pharmacy, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - William Richardson
- School of Pharmacy, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Eduard Vico Oton
- School of Life Sciences, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Manuel Romero
- School of Life Sciences, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
- The National Biofilms Innovation Centre, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Shaun N. Roberston
- School of Life Sciences, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
- The National Biofilms Innovation Centre, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Scott Grossman
- School of Pharmacy, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Tomas Sou
- Department of Pharmacy, Uppsala University, Uppsala SE-751 23, Sweden
| | - Ruiling Liu
- School of Pharmacy, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Nigel Halliday
- School of Life Sciences, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Irena Kukavica-Ibrulj
- Institut de Biologie Integrative et des Systemes, Universite Laval, Quebec G1 V 0A6, Canada
| | - Roger C. Levesque
- Institut de Biologie Integrative et des Systemes, Universite Laval, Quebec G1 V 0A6, Canada
| | | | - Barrie Kellam
- School of Pharmacy, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Jonas Emsley
- School of Pharmacy, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
- The National Biofilms Innovation Centre, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Stephan Heeb
- School of Life Sciences, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Paul Williams
- School of Life Sciences, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
- The National Biofilms Innovation Centre, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Michael J. Stocks
- School of Pharmacy, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
- The National Biofilms Innovation Centre, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Miguel Cámara
- School of Life Sciences, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
- The National Biofilms Innovation Centre, University of Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, U.K
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20
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Vetrivel A, Natchimuthu S, Subramanian V, Murugesan R. High-Throughput Virtual Screening for a New Class of Antagonist Targeting LasR of Pseudomonas aeruginosa. ACS OMEGA 2021; 6:18314-18324. [PMID: 34308062 PMCID: PMC8296597 DOI: 10.1021/acsomega.1c02191] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/16/2021] [Indexed: 05/28/2023]
Abstract
Pseudomonas aeruginosa, an opportunistic human pathogen, causes fatal effects in patients with cystic fibrosis and immunocompromised individuals and leads to around 1000 deaths annually. The quorum sensing mechanism of P. aeruginosa plays a major role in promoting biofilm formation and expression of virulent genes. Hence, quorum sensing inhibition is a promising novel approach to treat these bacterial infections as these organisms show a wide range of antibiotic resistance. Among the interconnected quorum sensing network of P. aeruginosa, targeting the las system is of increased interest as its principal receptor protein LasR is the earliest activated gene. It is also shown to be involved in the regulation of other virulence-associated genes. In this study, we have applied high-throughput virtual screening, an in silico computational method to identify a new class of LasR inhibitors that could serve as potent antagonists to treat P. aeruginosa-associated infections. Three-tire structure-based virtual screening was performed on the Schrödinger small molecule database, which resulted in 12 top hit compounds with docking scores lesser than -11.0 kcal/mol. Three of these best-scored compounds CACPD2011a-0001928786 (C1), CACPD2011a-0001927437 (C2), and CACPD2011a-0000896051 (C3) were further analyzed. The binding free energies of these compounds in complex with the target protein LasR (3IX4) were evaluated, and the pharmacokinetic properties were determined. The stability of the docked complexes was assessed by running a molecular dynamics simulation for 100 ns. Molecular dynamics simulation analysis revealed that all three compounds were found to be in stable contact with the protein over the entire simulation period. The antagonistic effect of these compounds was validated using the LasR reporter gene assay in the presence of acyl homoserine lactone. Significant reduction in the β-galactosidase enzyme activity was achieved at 100 nM concentration for all three compounds pursued. Hence, the present study provides strong evidence that these three compounds could serve as quorum sensing inhibitors of P. aeruginosa LasR protein and can be a probable candidate to treat Pseudomonas-associated infections.
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Affiliation(s)
- Aishwarya Vetrivel
- Department
of Biochemistry, Biotechnology and Bioinformatics, Avinashilingam Institute for Home Science and Higher Education for
Women, Coimbatore 641043, Tamil Nadu, India
| | - Santhi Natchimuthu
- Department
of Biochemistry, Biotechnology and Bioinformatics, Avinashilingam Institute for Home Science and Higher Education for
Women, Coimbatore 641043, Tamil Nadu, India
| | | | - Rajeswari Murugesan
- Department
of Biochemistry, Biotechnology and Bioinformatics, Avinashilingam Institute for Home Science and Higher Education for
Women, Coimbatore 641043, Tamil Nadu, India
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21
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Tobramycin Adaptation Enhances Policing of Social Cheaters in Pseudomonas aeruginosa. Appl Environ Microbiol 2021; 87:e0002921. [PMID: 33837019 DOI: 10.1128/aem.00029-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The Pseudomonas aeruginosa LasR-LasI (LasR-I) quorum sensing system regulates secreted proteases that can be exploited by cheaters, such as quorum sensing receptor-defective (lasR) mutants. lasR mutants emerge in populations growing on casein as a sole source of carbon and energy. These mutants are exploitative cheaters because they avoid the substantial cost of engaging in quorum sensing. Previous studies showed that quorum sensing increases resistance to some antibiotics, such as tobramycin. Here, we show that tobramycin suppressed the emergence of lasR mutants in casein-passaged populations. Several mutations accumulated in those populations, indicating evidence of antibiotic adaptation. We found that mutations in one gene, ptsP, increased antibiotic resistance and also pleiotropically increased production of a quorum sensing-controlled phenazine, pyocyanin. When passaged on casein, ptsP mutants suppressed cheaters in a manner that was tobramycin independent. We found that the mechanism of cheater suppression in ptsP mutants relied on pyocyanin, which acts as a policing toxin by selectively blocking growth of cheaters. Thus, tobramycin suppresses lasR mutants through two mechanisms: first, through direct effects on cheaters and, second, by selecting mutations in ptsP that suppressed cheating in a tobramycin-independent manner. This work demonstrates how adaptive mutations can alter the dynamics of cooperator-cheater relationships, which might be important for populations adapting to antibiotics during interspecies competition or infections. IMPORTANCE The opportunistic pathogen Pseudomonas aeruginosa is a model for understanding quorum sensing, a type of cell-cell signaling important for cooperation. Quorum sensing controls production of cooperative goods, such as exoenzymes, which are vulnerable to cheating by quorum sensing-defective mutants. Because uncontrolled cheating can ultimately cause a population to collapse, much focus has been on understanding how P. aeruginosa can control cheaters. We show that an antibiotic, tobramycin, can suppress cheaters in cooperating P. aeruginosa populations. Tobramycin suppresses cheaters directly because the cheaters are more susceptible to tobramycin than cooperators. Tobramycin also selects for mutations in a gene, ptsP, that suppresses cheaters independent of tobramycin through pleiotropic regulation of a policing toxin, pyocyanin. This work supports the idea that adaptation to antibiotics can have unexpected effects on the evolution of quorum sensing and has implications for understanding how cooperation evolves in dynamic bacterial communities.
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Migiyama Y, Sakata S, Iyama S, Tokunaga K, Saruwatari K, Tomita Y, Saeki S, Okamoto S, Ichiyasu H, Sakagami T. Airway Pseudomonas aeruginosa density in mechanically ventilated patients: clinical impact and relation to therapeutic efficacy of antibiotics. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2021; 25:59. [PMID: 33573691 PMCID: PMC7876981 DOI: 10.1186/s13054-021-03488-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/04/2021] [Indexed: 01/31/2023]
Abstract
Background The bacterial density of Pseudomonas aeruginosa is closely related to its pathogenicity. We evaluated the effect of airway P. aeruginosa density on the clinical course of mechanically ventilated patients and the therapeutic efficacy of antibiotics. Methods We retrospectively analyzed data of mechanically ventilated ICU patients with P. aeruginosa isolated from endotracheal aspirates. Patients were divided into three groups according to the peak P. aeruginosa density during ICU stay: low (≤ 104 cfu/mL), moderate (105‒106 cfu/mL), and high (≥ 107 cfu/mL) peak density groups. The relationship between peak P. aeruginosa density and weaning from mechanical ventilation, risk factors for isolation of high peak density of P. aeruginosa, and antibiotic efficacy were investigated using multivariate and propensity score-matched analyses. Results Four-hundred-and-sixty-one patients were enrolled. Patients with high peak density of P. aeruginosa had higher inflammation and developed more severe respiratory infections. High peak density of P. aeruginosa was independently associated with few ventilator-free days on day 28 (P < 0.01) and increased ICU mortality (P = 0.047). Risk factors for high peak density of P. aeruginosa were prolonged mechanical ventilation (odd ratio [OR] 3.07 95% confidence interval [CI] 1.35‒6.97), non-antipseudomonal cephalosporins (OR 2.17, 95% CI 1.35‒3.49), hyperglycemia (OR 2.01, 95% CI 1.26‒3.22) during ICU stay, and respiratory diseases (OR 1.9, 95% CI 1.12‒3.23). Isolation of commensal colonizer was associated with lower risks of high peak density of P. aeruginosa (OR 0.43, 95% CI 0.26‒0.73). Propensity score-matched analysis revealed that antibiotic therapy for patients with ventilator-associated tracheobronchitis improved weaning from mechanical ventilation only in the high peak P. aeruginosa group. Conclusions Patients with high peak density of P. aeruginosa had worse ventilator outcome and ICU mortality. In patients with ventilator-associated tracheobronchitis, antibiotic therapy was associated with favorable ventilator weaning only in the high peak P. aeruginosa density group, and bacterial density could be a good therapeutic indicator for ventilator-associated tracheobronchitis due to P. aeruginosa.![]()
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Affiliation(s)
- Yohei Migiyama
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan. .,Demachi Naika, Kumamoto, Japan.
| | - Shinya Sakata
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Shinji Iyama
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Kentaro Tokunaga
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan.,Department of Critical Care Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Koichi Saruwatari
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Yusuke Tomita
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Sho Saeki
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Shinichiro Okamoto
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Hidenori Ichiyasu
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan
| | - Takuro Sakagami
- Department of Respiratory Medicine, Kumamoto University Hospital, Kumamoto, Japan
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23
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Molecular simulations of lipid membrane partitioning and translocation by bacterial quorum sensing modulators. PLoS One 2021; 16:e0246187. [PMID: 33561158 PMCID: PMC7872223 DOI: 10.1371/journal.pone.0246187] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/15/2021] [Indexed: 12/18/2022] Open
Abstract
Quorum sensing (QS) is a bacterial communication process mediated by both native and non-native small-molecule quorum sensing modulators (QSMs), many of which have been synthesized to disrupt QS pathways. While structure-activity relationships have been developed to relate QSM structure to the activation or inhibition of QS receptors, less is known about the transport mechanisms that enable QSMs to cross the lipid membrane and access intracellular receptors. In this study, we used atomistic MD simulations and an implicit solvent model, called COSMOmic, to analyze the partitioning and translocation of QSMs across lipid bilayers. We performed umbrella sampling at atomistic resolution to calculate partitioning and translocation free energies for a set of naturally occurring QSMs, then used COSMOmic to screen the water-membrane partition and translocation free energies for 50 native and non-native QSMs that target LasR, one of the LuxR family of quorum-sensing receptors. This screening procedure revealed the influence of systematic changes to head and tail group structures on membrane partitioning and translocation free energies at a significantly reduced computational cost compared to atomistic MD simulations. Comparisons with previously determined QSM activities suggest that QSMs that are least likely to partition into the bilayer are also less active. This work thus demonstrates the ability of the computational protocol to interrogate QSM-bilayer interactions which may help guide the design of new QSMs with engineered membrane interactions.
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24
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Yashkin A, Rayo J, Grimm L, Welch M, Meijler MM. Short-chain reactive probes as tools to unravel the Pseudomonas aeruginosa quorum sensing regulon. Chem Sci 2021; 12:4570-4581. [PMID: 34163722 PMCID: PMC8179429 DOI: 10.1039/d0sc04444j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 01/28/2021] [Indexed: 11/21/2022] Open
Abstract
In recent years, the world has seen a troubling increase in antibiotic resistance among bacterial pathogens. In order to provide alternative strategies to combat bacterial infections, it is crucial deepen our understanding into the mechanisms that pathogens use to thrive in complex environments. Most bacteria use sophisticated chemical communication systems to sense their population density and coordinate gene expression in a collective manner, a process that is termed "quorum sensing" (QS). The human pathogen Pseudomonas aeruginosa uses several small molecules to regulate QS, and one of them is N-butyryl-l-homoserine lactone (C4-HSL). Using an activity-based protein profiling (ABPP) strategy, we designed biomimetic probes with a photoreactive group and a 'click' tag as an analytical handle. Using these probes, we have identified previously uncharacterized proteins that are part of the P. aeruginosa QS network, and we uncovered an additional role for this natural autoinducer in the virulence regulon of P. aeruginosa, through its interaction with PhzB1/2 that results in inhibition of pyocyanin production.
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Affiliation(s)
- Alex Yashkin
- Dept. of Chemistry, The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev Be'er Sheva 8410501 Israel
| | - Josep Rayo
- Dept. of Chemistry, The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev Be'er Sheva 8410501 Israel
| | - Larson Grimm
- Dept. of Biochemistry, University of Cambridge UK
| | - Martin Welch
- Dept. of Biochemistry, University of Cambridge UK
| | - Michael M Meijler
- Dept. of Chemistry, The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev Be'er Sheva 8410501 Israel
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25
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Juárez-Rodríguez MM, Cortes-López H, García-Contreras R, González-Pedrajo B, Díaz-Guerrero M, Martínez-Vázquez M, Rivera-Chávez JA, Soto-Hernández RM, Castillo-Juárez I. Tetradecanoic Acids With Anti-Virulence Properties Increase the Pathogenicity of Pseudomonas aeruginosa in a Murine Cutaneous Infection Model. Front Cell Infect Microbiol 2021; 10:597517. [PMID: 33585272 PMCID: PMC7876447 DOI: 10.3389/fcimb.2020.597517] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/08/2020] [Indexed: 12/25/2022] Open
Abstract
Blocking virulence is a promising alternative to counteract Pseudomonas aeruginosa infections. In this regard, the phenomenon of cell-cell communication by quorum sensing (QS) is an important anti-virulence target. In this field, fatty acids (FA) have gained notoriety for their role as autoinducers, as well as anti-virulence molecules in vitro, like some saturated FA (SAFA). In this study, we analyzed the anti-virulence activity of SAFA with 12 to18 carbon atoms and compared their effect with the putative autoinducer cis-2-decenoic acid (CDA). The effect of SAFA on six QS-regulated virulence factors and on the secretion of the exoenzyme ExoU was evaluated. In addition, a murine cutaneous infection model was used to determine their influence on the establishment and damage caused by P. aeruginosa PA14. Dodecanoic (lauric, C12:0) and tetradecanoic (myristic, C14:0) acids (SAFA C12-14) reduced the production of pyocyanin by 35-58% at 40 and 1,000 µM, while CDA inhibited it 62% at a 3.1 µM concentration. Moreover, the SAFA C12-14 reduced swarming by 90% without affecting biofilm formation. In contrast, CDA reduced the biofilm by 57% at 3 µM but did not affect swarming. Furthermore, lauric and myristic acids abolished ExoU secretion at 100 and 50 µM respectively, while CDA reduced it by ≈ 92% at 100 µM. Remarkably, the coadministration of myristic acid (200 and 1,000 µM) with P. aeruginosa PA14 induced greater damage and reduced survival of the animals up to 50%, whereas CDA to 500 µM reduced the damage without affecting the viability of the PA14 strain. Hence, our results show that SAFA C12-14 and CDA have a role in regulation of P. aeruginosa virulence, although their inhibition/activation molecular mechanisms are different in complex environments such as in vivo systems.
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Affiliation(s)
| | - Humberto Cortes-López
- Laboratorio de Fitoquímica, Posgrado de Botánica, Colegio de Postgraduados, Texcoco, Mexico
| | - Rodolfo García-Contreras
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Miguel Díaz-Guerrero
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Mariano Martínez-Vázquez
- Departamento de Productos Naturales, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - José Alberto Rivera-Chávez
- Departamento de Productos Naturales, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | - Israel Castillo-Juárez
- Laboratorio de Fitoquímica, Posgrado de Botánica, Colegio de Postgraduados, Texcoco, Mexico
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Iron interferes with quorum sensing-mediated cooperation in Pseudomonas aeruginosa by affecting the expression of ppyR and mexT, in addition to rhlR. J Microbiol 2020; 58:938-944. [PMID: 32997304 DOI: 10.1007/s12275-020-0264-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 10/23/2022]
Abstract
The stabilization of quorum sensing (QS) is vital for bacterial survival in various environments. Although the mechanisms of QS stabilization in certain conditions have been well studied, the impact of environmental factors has received much less attention. In this study, we show that the supplementation of 25 µM iron in competition experiments and 50 µM in evolution experiments to casein growth cultures significantly increased the possibility of population collapse by affecting elastase production. However, the expression of lasI and lasR remained constant regardless of iron concentration and hence this effect was not through interference with the LasIR circuit, which mainly regulates the secretion of elastase in Pseudomonas aeruginosa. However, the expression of rhlR was significantly inhibited by iron treatment, which could affect the production of elastase. Further, based on both reverse transcription quantitative polymerase chain reaction and gene knock-out assays, we show that iron inhibits the transcription of ppyR and enhances the expression of mexT, both of which decrease elastase production and correspondingly interfere with QS stabilization. Our findings show that environmental factors can affect the genes of QS circuits, interfering with QS stabilization. These findings are not only beneficial in understanding the mechanistic effect of iron on QS stabilization, but also demonstrate the complexity of QS stabilization by linking non-QS-related genes with QS traits.
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27
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Microbial biofilm ecology, in silico study of quorum sensing receptor-ligand interactions and biofilm mediated bioremediation. Arch Microbiol 2020; 203:13-30. [PMID: 32785735 DOI: 10.1007/s00203-020-02012-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 07/17/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022]
Abstract
Biofilms are structured microbial communities of single or multiple populations in which microbial cells adhere to a surface and get embedded in extracellular polymeric substances (EPS). This review attempts to explain biofilm architecture, development phases, and forces that drive bacteria to promote biofilm mode of growth. Bacterial chemical communication, also known as Quorum sensing (QS), which involves the production, detection, and response to small molecules called autoinducers, is highlighted. The review also provides a brief outline of interspecies and intraspecies cell-cell communication. Additionally, we have performed docking studies using Discovery Studio 4.0, which has enabled our understanding of the prominent interactions between autoinducers and their receptors in different bacterial species while also scoring their interaction energies. Receptors, such as LuxN (Phosphoreceiver domain and RecA domain), LuxP, and LuxR, interacted with their ligands (AI-1, AI-2, and AHL) with a CDocker interaction energy of - 31.6083 kcal/mole; - 34.5821 kcal/mole, - 48.2226 kcal/mole and - 41.5885 kcal/mole, respectively. Since biofilms are ideal for the remediation of contaminants due to their high microbial biomass and their potential to immobilize pollutants, this article also provides an overview of biofilm-mediated bioremediation.
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28
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Badal D, Jayarani AV, Kollaran MA, Kumar A, Singh V. Pseudomonas aeruginosa biofilm formation on endotracheal tubes requires multiple two-component systems. J Med Microbiol 2020; 69:906-919. [PMID: 32459613 DOI: 10.1099/jmm.0.001199] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Introduction. Indwelling medical devices such as endotracheal tubes (ETTs), urinary catheters, vascular access devices, tracheostomies and feeding tubes are often associated with hospital-acquired infections. Bacterial biofilm formed on the ETTs in intubated patients is a significant risk factor associated with ventilator-associated pneumonia. Pseudomonas aeruginosa is one of the four frequently encountered bacteria responsible for causing pneumonia, and the biofilm formation on ETTs. However, understanding of biofilm formation on ETT and interventions to prevent biofilm remains lagging. The ability to sense and adapt to external cues contributes to their success. Thus, the biofilm formation is likely to be influenced by the two-component systems (TCSs) that are composed of a membrane-associated sensor kinase and an intracellular response regulator.Aim. This study aims to establish an in vitro method to analyse the P. aeruginosa biofilm formation on ETTs, and identify the TCSs that contribute to this process.Methodology. In total, 112 P. aeruginosa PA14 TCS mutants were tested for their ability to form biofilm on ETTs, their effect on quorum sensing (QS) and motility.Results. Out of 112 TCS mutants studied, 56 had altered biofilm biomass on ETTs. Although the biofilm formation on ETTs is QS-dependent, none of the 56 loci controlled quorum signal. Of these, 18 novel TCSs specific to ETT biofilm were identified, namely, AauS, AgtS, ColR, CopS, CprR, NasT, KdpD, ParS, PmrB, PprA, PvrS, RcsC, PA14_11120, PA14_32580, PA14_45880, PA14_49420, PA14_52240, PA14_70790. The set of 56 included the GacS network, TCS proteins involved in fimbriae synthesis, TCS proteins involved in antimicrobial peptide resistance, and surface-sensing. Additionally, several of the TCS-encoding genes involved in biofilm formation on ETTs were found to be linked to flagellum-dependent swimming motility.Conclusions. Our study established an in vitro method for studying P. aeruginosa biofilm formation on the ETT surfaces. We also identified novel ETT-specific TCSs that could serve as targets to prevent biofilm formation on indwelling devices frequently used in clinical settings.
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Affiliation(s)
- Divakar Badal
- Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Abhijith Vimal Jayarani
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Mohammed Ameen Kollaran
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Aloke Kumar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA.,Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
| | - Varsha Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, INDIA.,Department of Biosystems Sciences and Engineering, Indian Institute of Science, Bangalore, Karnataka, INDIA
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29
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Rémy B, Plener L, Decloquement P, Armstrong N, Elias M, Daudé D, Chabrière É. Lactonase Specificity Is Key to Quorum Quenching in Pseudomonas aeruginosa. Front Microbiol 2020; 11:762. [PMID: 32390993 PMCID: PMC7193897 DOI: 10.3389/fmicb.2020.00762] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/30/2020] [Indexed: 12/31/2022] Open
Abstract
The human opportunistic pathogen Pseudomonas aeruginosa orchestrates the expression of many genes in a cell density-dependent manner by using quorum sensing (QS). Two acyl-homoserine lactones (AHLs) are involved in QS circuits and contribute to the regulation of virulence factors production, biofilm formation, and antimicrobial sensitivity. Disrupting QS, a strategy referred to as quorum quenching (QQ) can be achieved using exogenous AHL-degrading lactonases. However, the importance of enzyme specificity on quenching efficacy has been poorly investigated. Here, we used two lactonases both targeting the signal molecules N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12 HSL) and butyryl-homoserine lactone (C4 HSL) albeit with different efficacies on C4 HSL. Interestingly, both lactonases similarly decreased AHL concentrations and comparably impacted the expression of AHL-based QS genes. However, strong variations were observed in Pseudomonas Quinolone Signal (PQS) regulation depending on the lactonase used. Both lactonases were also found to decrease virulence factors production and biofilm formation in vitro, albeit with different efficiencies. Unexpectedly, only the lactonase with lower efficacy on C4 HSL was able to inhibit P. aeruginosa pathogenicity in vivo in an amoeba infection model. Similarly, proteomic analysis revealed large variations in protein levels involved in antibiotic resistance, biofilm formation, virulence and diverse cellular mechanisms depending on the chosen lactonase. This global analysis provides evidences that QQ enzyme specificity has a significant impact on the modulation of QS-associated behavior in P. aeruginosa PA14.
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Affiliation(s)
- Benjamin Rémy
- Aix Marseille University, Institut de Recherche pour le Développement, Assistance Publique - Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infections, Institut Hospitalo-Universitaire-Méditerranée Infection, Marseille, France.,Gene&GreenTK, Marseille, France
| | | | - Philippe Decloquement
- Aix Marseille University, Institut de Recherche pour le Développement, Assistance Publique - Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infections, Institut Hospitalo-Universitaire-Méditerranée Infection, Marseille, France
| | - Nicholas Armstrong
- Aix Marseille University, Institut de Recherche pour le Développement, Assistance Publique - Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infections, Institut Hospitalo-Universitaire-Méditerranée Infection, Marseille, France
| | - Mikael Elias
- Department of Biochemistry, Molecular Biology and Biophysics - BioTechnology Institute, University of Minnesota, St. Paul, MN, United States
| | | | - Éric Chabrière
- Aix Marseille University, Institut de Recherche pour le Développement, Assistance Publique - Hôpitaux de Marseille, Microbes Evolution Phylogeny and Infections, Institut Hospitalo-Universitaire-Méditerranée Infection, Marseille, France
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30
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Manson DE, O’Reilly MC, Nyffeler KE, Blackwell HE. Design, Synthesis, and Biochemical Characterization of Non-Native Antagonists of the Pseudomonas aeruginosa Quorum Sensing Receptor LasR with Nanomolar IC 50 Values. ACS Infect Dis 2020; 6:649-661. [PMID: 32037806 DOI: 10.1021/acsinfecdis.9b00518] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Quorum sensing (QS), a bacterial cell-to-cell communication system mediated by small molecules and peptides, has received significant interest as a potential target to block infection. The common pathogen Pseudomonas aeruginosa uses QS to regulate many of its virulence phenotypes at high cell densities, and the LasR QS receptor plays a critical role in this process. Small molecule tools that inhibit LasR activity would serve to illuminate its role in P. aeruginosa virulence, but we currently lack highly potent and selective LasR antagonists, despite considerable research in this area. V-06-018, an abiotic small molecule discovered in a high-throughput screen, represents one of the most potent known LasR antagonists but has seen little study since its initial report. Herein, we report a systematic study of the structure-activity relationships (SARs) that govern LasR antagonism by V-06-018. We synthesized a focused library of V-06-018 derivatives and evaluated the library for bioactivity using a variety of cell-based LasR reporter systems. The SAR trends revealed by these experiments allowed us to design probes with 10-fold greater potency than that of V-06-018 and 100-fold greater potency than other commonly used N-acyl-l-homoserine lactone (AHL)-based LasR antagonists, along with high selectivities for LasR. Biochemical experiments to probe the mechanism of antagonism by V-06-018 and its analogues support these compounds interacting with the native ligand-binding site in LasR and, at least in part, stabilizing an inactive form of the protein. The compounds described herein are the most potent and efficacious antagonists of LasR known and represent robust probes both for characterizing the mechanisms of LuxR-type QS and for chemical biology research in general in the growing QS field.
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Affiliation(s)
- Daniel E. Manson
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Matthew C. O’Reilly
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Kayleigh E. Nyffeler
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin−Madison, 110 University Ave., Madison, Wisconsin 53706 United States
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Abstract
It is not fully understood how phosphate deficiency could influence the virulence of Pseudomonas aeruginosa through modulation of the bacterial QS systems. This report presents a systemic investigation on the impact of phosphate depletion on the hierarchy of quorum sensing systems of P. aeruginosa. The results showed that phosphate stress could have an extensive impact on the QS networks of this bacterial pathogen. Among the 7 QS regulatory genes representing the 3 sets of QS systems tested, 4 were significantly upregulated by phosphate depletion stress through the PhoR/PhoB two-component regulatory system, especially the upstream QS regulatory gene lasI. We also present evidence that the response regulator PhoB was a strong competitor against the las regulators LasR and RsaL for the lasI promoter, unveiling the mechanistic basis of the process by which phosphate stress could modulate the bacterial QS systems. The hierarchical quorum sensing (QS) systems of Pseudomonas aeruginosa, consisting of las, pqs, and rhl, coordinate the expression of bacterial virulence genes. Previous studies showed that under phosphate deficiency conditions, two-component regulatory system PhoRB could activate various genes involved in cytotoxicity through modulation of QS systems, but the mechanism by which PhoR/PhoB influences QS remains largely unknown. Here, we provide evidence that among the key QS regulatory genes in P. aeruginosa, rhlR, pqsA, mvfR, and lasI were activated by the response regulator PhoB under phosphate-depleted conditions. We show that PhoB is a strong competitor against LasR and RsaL for binding to the promoter of lasI and induces significant expression of lasI, rhlR, and mvfR. However, expression of lasI, encoding the signal 3-oxo-C12-HSL, was increased only marginally under the same phosphate-depleted conditions. This seeming inconsistency was attributed to the induction of pvdQ, which encodes an enzyme for degradation of 3-oxo-C12-HSL signal molecules. Taken together, the results from this study demonstrate that through the two-component regulatory system PhoR/PhoB, phosphate depletion stress could influence the QS network by modulating several key regulators, including lasI, rhlR, mvfR, and pvdQ. The findings highlight not only the potency of the PhoR/PhoB-mediated bacterial stress response mechanism but also the plasticity of the P. aeruginosa QS systems in coping with the changed environmental conditions. IMPORTANCE It is not fully understood how phosphate deficiency could influence the virulence of Pseudomonas aeruginosa through modulation of the bacterial QS systems. This report presents a systemic investigation on the impact of phosphate depletion on the hierarchy of quorum sensing systems of P. aeruginosa. The results showed that phosphate stress could have an extensive impact on the QS networks of this bacterial pathogen. Among the 7 QS regulatory genes representing the 3 sets of QS systems tested, 4 were significantly upregulated by phosphate depletion stress through the PhoR/PhoB two-component regulatory system, especially the upstream QS regulatory gene lasI. We also present evidence that the response regulator PhoB was a strong competitor against the las regulators LasR and RsaL for the lasI promoter, unveiling the mechanistic basis of the process by which phosphate stress could modulate the bacterial QS systems.
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32
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Malešević M, Di Lorenzo F, Filipić B, Stanisavljević N, Novović K, Senerovic L, Polović N, Molinaro A, Kojić M, Jovčić B. Pseudomonas aeruginosa quorum sensing inhibition by clinical isolate Delftia tsuruhatensis 11304: involvement of N-octadecanoylhomoserine lactones. Sci Rep 2019; 9:16465. [PMID: 31712724 PMCID: PMC6848482 DOI: 10.1038/s41598-019-52955-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 10/26/2019] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is one of the most common opportunistic pathogens that use quorum sensing (QS) system to regulate virulence factors expression and biofilm development. Delftia sp. 11304 was selected among 663 Gram-negative clinical isolates based on its QS inhibitory activity against P. aeruginosa MMA83 clinical isolate. Whole genome sequencing identified this isolate as D. tsuruhatensis and revealed genetic armamentarium of virulence factors and antibiotic resistance determinants. Ethyl acetate extract of D. tsuruhatensis 11304 culture supernatant (QSI extract) prevented biofilm formation of P. aeruginosa MMA83, but was unable to cause biofilm decomposition. QSI extract showed a synergistic effect in combination with meropenem and gentamycin, against P. aeruginosa MMA83. A dose-dependent reduction of the virulence factors: elastase, rhamnolipid and pyocyanin production by P. aeruginosa MMA83 and significant downregulation of lasI, lasR, rhlI, rhlR, pqs and mvfR expression were observed. Matrix-assisted Laser Desorption Ionization (MALDI) mass spectrometry of D. tsuruhatensis 11304 QSI extract revealed the presence of N-acyl homoserine lactones (AHL) with chain lengths of C12 to C18. The main ion peak was identified as N-octadecanoylhomoserine lactone (C18-HSL). Commercial C18-HSL (20 µM) reduced pyocyanin production as well as mRNA level of the lasI gene. A novel AHL species, dihydroxy-N-octadecanoylhomoserine lactone, was also described.
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Affiliation(s)
- Milka Malešević
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, 11010, Serbia
| | - Flaviana Di Lorenzo
- University of Napoli Federico II, Department of Chemical Sciences, Napoli, 80126, Italy
| | - Brankica Filipić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, 11010, Serbia.,Faculty of Pharmacy, University of Belgrade, Belgrade, 11221, Serbia
| | - Nemanja Stanisavljević
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, 11010, Serbia
| | - Katarina Novović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, 11010, Serbia
| | - Lidija Senerovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, 11010, Serbia
| | - Natalija Polović
- Faculty of Chemistry, University of Belgrade, Belgrade, 11000, Serbia
| | - Antonio Molinaro
- University of Napoli Federico II, Department of Chemical Sciences, Napoli, 80126, Italy
| | - Milan Kojić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, 11010, Serbia
| | - Branko Jovčić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, 11010, Serbia. .,Faculty of Biology, University of Belgrade, Belgrade, 11000, Serbia.
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33
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Mion S, Rémy B, Plener L, Brégeon F, Chabrière E, Daudé D. Quorum Quenching Lactonase Strengthens Bacteriophage and Antibiotic Arsenal Against Pseudomonas aeruginosa Clinical Isolates. Front Microbiol 2019; 10:2049. [PMID: 31551983 PMCID: PMC6734170 DOI: 10.3389/fmicb.2019.02049] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 08/20/2019] [Indexed: 01/21/2023] Open
Abstract
Many bacteria use quorum sensing (QS), a bacterial communication system based on the diffusion and perception of small signaling molecules, to synchronize their behavior in a cell-density dependent manner. QS regulates the expression of many genes associated with virulence factor production and biofilm formation. This latter is known to be involved in antibiotic and phage resistance mechanisms. Therefore, disrupting QS, a strategy known as quorum quenching (QQ), appears to be an interesting way to reduce bacterial virulence and increase antibiotic and phage treatment efficiency. In this study, the ability of the QQ enzyme SsoPox-W263I, a lactonase able to degrade acyl-homoserine lactones, was investigated for quenching both virulence and biofilm formation in clinical isolates of Pseudomonas aeruginosa from diabetic foot ulcers, as well as in the PA14 model strain. These strains were further evolved to resist to bacteriophage cocktails. Overall, 10 antibiotics or bacteriophage resistant strains were evaluated and SsoPox-W263I was shown to decrease pyocyanin, protease and elastase production in all strains. Furthermore, a reduction of more than 70% of biofilm formation was achieved in six out of ten strains. This anti-virulence potential was confirmed in vivo using an amoeba infection model, showing enhanced susceptibility toward amoeba of nine out of ten P. aeruginosa isolates upon QQ. This amoeba model was further used to demonstrate the ability of SsoPox-W263I to enhance the susceptibility of sensitive and phage resistant bacteria to bacteriophage and antibiotic.
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Affiliation(s)
- Sonia Mion
- Aix-Marseille University, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
| | - Benjamin Rémy
- Aix-Marseille University, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France.,Gene&GreenTK, Marseille, France
| | | | - Fabienne Brégeon
- Aix-Marseille University, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France.,Service des Explorations Fonctionnelles Respiratoires Centre Hospitalo Universitaire Nord, Pôle Cardio-Vasculaire et Thoracique, Assistance Publique des Hôpitaux de Marseille, Marseille, France
| | - Eric Chabrière
- Aix-Marseille University, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
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34
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Mion S, Plener L, Rémy B, Daudé D, Chabrière É. Lactonase SsoPox modulates CRISPR-Cas expression in gram-negative proteobacteria using AHL-based quorum sensing systems. Res Microbiol 2019; 170:296-299. [PMID: 31279087 DOI: 10.1016/j.resmic.2019.06.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/24/2019] [Accepted: 06/25/2019] [Indexed: 01/15/2023]
Abstract
Quorum sensing (QS) is a molecular communication system that bacteria use to harmonize the regulation of genes in a cell density-dependent manner. In proteobacteria, QS is involved, among others, in virulence, biofilm formation or CRISPR-Cas gene regulation. Here, we report for the first time the effect of a QS-interfering enzyme to alter the regulation of CRISPR-Cas systems in model and clinical strains of Pseudomonas aeruginosa, as well as in the marine bacterium Chromobacterium violaceum CV12472. The expression of CRISPR-Cas genes decreased in most cases suggesting that enzymatic disruption of QS is promising for modulating phage-bacteria interactions.
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Affiliation(s)
- Sonia Mion
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France
| | - Laure Plener
- Gene&GreenTK, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
| | - Benjamin Rémy
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France; Gene&GreenTK, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
| | - David Daudé
- Gene&GreenTK, 19-21 Boulevard Jean Moulin, 13005 Marseille, France.
| | - Éric Chabrière
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU-Méditerranée Infection, Marseille, France.
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35
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Quorum Sensing as Antivirulence Target in Cystic Fibrosis Pathogens. Int J Mol Sci 2019; 20:ijms20081838. [PMID: 31013936 PMCID: PMC6515091 DOI: 10.3390/ijms20081838] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/11/2019] [Accepted: 04/11/2019] [Indexed: 12/17/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive genetic disorder which leads to the secretion of a viscous mucus layer on the respiratory epithelium that facilitates colonization by various bacterial pathogens. The problem of drug resistance has been reported for all the species able to colonize the lung of CF patients, so alternative treatments are urgently needed. In this context, a valid approach is to investigate new natural and synthetic molecules for their ability to counteract alternative pathways, such as virulence regulating quorum sensing (QS). In this review we describe the pathogens most commonly associated with CF lung infections: Staphylococcus aureus, Pseudomonas aeruginosa, species of the Burkholderia cepacia complex and the emerging pathogens Stenotrophomonas maltophilia, Haemophilus influenzae and non-tuberculous Mycobacteria. For each bacterium, the QS system(s) and the molecules targeting the different components of this pathway are described. The amount of investigations published in the last five years clearly indicate the interest and the expectations on antivirulence therapy as an alternative to classical antibiotics.
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36
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Kollaran AM, Joge S, Kotian HS, Badal D, Prakash D, Mishra A, Varma M, Singh V. Context-Specific Requirement of Forty-Four Two-Component Loci in Pseudomonas aeruginosa Swarming. iScience 2019; 13:305-317. [PMID: 30877999 PMCID: PMC6423354 DOI: 10.1016/j.isci.2019.02.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/18/2018] [Accepted: 02/26/2019] [Indexed: 11/30/2022] Open
Abstract
Swarming in Pseudomonas aeruginosa is a coordinated movement of bacteria over semisolid surfaces (0.5%-0.7% agar). On soft agar, P. aeruginosa exhibits a dendritic swarm pattern, with multiple levels of branching. However, the swarm patterns typically vary depending upon the experimental design. In the present study, we show that the pattern characteristics of P. aeruginosa swarm are highly environment dependent. We define several quantifiable, macroscale features of the swarm to study the plasticity of the swarm, observed across different nutrient formulations. Furthermore, through a targeted screen of 113 two-component system (TCS) loci of the P. aeruginosa strain PA14, we show that forty-four TCS genes regulate swarming in PA14 in a contextual fashion. However, only four TCS genes-fleR, fleS, gacS, and PA14_59770-were found essential for swarming. Notably, many swarming-defective TCS mutants were found highly efficient in biofilm formation, indicating opposing roles for many TCS loci.
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Affiliation(s)
- Ameen M Kollaran
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Shubham Joge
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Harshitha S Kotian
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Divakar Badal
- Biosystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Deep Prakash
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Ayushi Mishra
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Manoj Varma
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India; Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Varsha Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka 560012, India; Biosystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India.
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37
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Fontaine BM, Duggal Y, Weinert EE. Exploring the Links between Nucleotide Signaling and Quorum Sensing Pathways in Regulating Bacterial Virulence. ACS Infect Dis 2018; 4:1645-1655. [PMID: 30381948 DOI: 10.1021/acsinfecdis.8b00255] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The survival of all organisms depends on implementation of appropriate phenotypic responses upon perception of relevant environmental stimuli. Sensory inputs are propagated via interconnected biochemical and/or electrical cascades mediated by diverse signaling molecules, including gases, metal cations, lipids, peptides, and nucleotides. These networks often comprise second messenger signaling systems in which a ligand (the primary messenger) binds to an extracellular receptor, thereby altering the intracellular concentration of a second messenger molecule which ultimately modulates gene expression through interaction with various effectors. The identification of intersections of these signaling pathways, such as nucleotide second messengers and quorum sensing, provides new insights into the mechanisms by which bacteria use multiple inputs to regulate cellular metabolism and phenotypes. Further investigations of the overlap between bacterial signaling pathways may yield new targets and methods to control bacterial behavior, such as biofilm formation and virulence.
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Affiliation(s)
- Benjamin M. Fontaine
- Department of Chemistry, Emory University, 1515 Dickey Drive NE, Atlanta, Georgia 30322, United States
| | - Yashasvika Duggal
- Department of Chemistry, Emory University, 1515 Dickey Drive NE, Atlanta, Georgia 30322, United States
| | - Emily E. Weinert
- Department of Chemistry, Emory University, 1515 Dickey Drive NE, Atlanta, Georgia 30322, United States
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38
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Alcalde-Rico M, Olivares-Pacheco J, Alvarez-Ortega C, Cámara M, Martínez JL. Role of the Multidrug Resistance Efflux Pump MexCD-OprJ in the Pseudomonas aeruginosa Quorum Sensing Response. Front Microbiol 2018; 9:2752. [PMID: 30532741 PMCID: PMC6266676 DOI: 10.3389/fmicb.2018.02752] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/26/2018] [Indexed: 11/15/2022] Open
Abstract
Multidrug efflux pumps constitute a category of antibiotic resistance determinants that are a part of the core bacterial genomes. Given their conservation, it is conceivable that they present functions beyond the extrusion of antibiotics currently used for therapy. Pseudomonas aeruginosa stands as a relevant respiratory pathogen, with a high prevalence at hospitals and in cystic fibrosis patients. Part of its success relies on its low susceptibility to antibiotics and on the production of virulence factors, whose expression is regulated in several cases by quorum sensing (QS). We found that overexpression of the MexCD-OprJ multidrug efflux pump shuts down the P. aeruginosa QS response. Our results support that MexCD-OprJ extrudes kynurenine, a precursor of the alkyl-quinolone signal (AQS) molecules. Anthranilate and octanoate, also AQS precursors, do not seem to be extruded by MexCD-OprJ. Kynurenine extrusion is not sufficient to reduce the QS response in a mutant overexpressing this efflux pump. Impaired QS response is mainly due to the extrusion of 4-hydroxy-2-heptylquinoline (HHQ), the precursor of the Pseudomonas Quinolone Signal (PQS), leading to low PQS intracellular levels and reduced production of QS signal molecules. As the consequence, the expression of QS-regulated genes is impaired and the production of QS-regulated virulence factors strongly decreases in a MexCD-OprN P. aeruginosa overexpressing mutant. Previous work showed that MexEF-OprJ, another P. aeruginosa efflux pump, is also able of extruding kynurenine and HHQ. However, opposite to our findings, the QS defect in a MexEF-OprN overproducer is due to kynurenine extrusion. These results indicate that, although efflux pumps can share some substrates, the affinity for each of them can be different. Although the QS response is triggered by population density, information on additional elements able of modulating such response is still scarce. This is particularly important in the case of P. aeruginosa lung chronic infections, a situation in which QS-defective mutants are accumulated. If MexCD-OprJ overexpression alleviates the cost associated to triggering the QS response when un-needed, it could be possible that MexCD-OprJ antibiotic resistant overproducer strains might be selected even in the absence of antibiotic selective pressure, acting as antibiotic resistant cheaters in heterogeneous P. aeruginosa populations.
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Affiliation(s)
- Manuel Alcalde-Rico
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Jorge Olivares-Pacheco
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carolina Alvarez-Ortega
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Miguel Cámara
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - José Luis Martínez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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39
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Yu Z, Ding Y, Yin J, Yu D, Zhang J, Zhang M, Ding M, Zhong W, Qiu J, Li J. Dissemination of Genetic Acquisition/Loss Provides a Variety of Quorum Sensing Regulatory Properties in Pseudoalteromonas. Int J Mol Sci 2018; 19:E3636. [PMID: 30453700 PMCID: PMC6275029 DOI: 10.3390/ijms19113636] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 01/20/2023] Open
Abstract
A bstract: Quorum sensing (QS) enables single-celled bacteria to communicate with chemical signals in order to synchronize group-level bacterial behavior. Pseudoalteromonas are marine bacteria found in versatile environments, of which QS regulation for their habitat adaptation is extremely fragmentary. To distinguish genes required for QS regulation in Pseudoalteromonas, comparative genomics was deployed to define the pan-genomics for twelve isolates and previously-sequenced genomes, of which acyl-homoserine lactone (AHL)-based QS traits were characterized. Additionally, transposon mutagenesis was used to identify the essential QS regulatory genes in the selected Pseudoalteromonas isolate. A remarkable feature showed that AHL-based colorization intensity of biosensors induced by Pseudoalteromonas most likely correlates with QS regulators genetic heterogeneity within the genus. This is supported by the relative expression levels of two of the main QS regulatory genes (luxO and rpoN) analyzed in representative Pseudoalteromonas isolates. Notably, comprehensive QS regulatory schema and the working model proposed in Pseudoalteromonas seem to phylogenetically include the network architectures derived from Escherichia coli, Pseudomonas, and Vibrio. Several associated genes were mapped by transposon mutagenesis. Among them, a right origin-binding protein-encoding gene (robp) was functionally identified as a positive QS regulatory gene. This gene lies on a genomic instable region and exists in the aforementioned bioinformatically recruited QS regulatory schema. The obtained data emphasize that the distinctly- and hierarchically-organized mechanisms probably target QS association in Pseudoalteromonas dynamic genomes, thus leading to bacterial ability to accommodate their adaption fitness and survival advantages.
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Affiliation(s)
- Zhiliang Yu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Yajuan Ding
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Dongliang Yu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Jiadi Zhang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Mengting Zhang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Mengdan Ding
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Weihong Zhong
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Juanping Qiu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Jun Li
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
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40
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Palmer AG, Senechal AC, Haire TC, Mehta NP, Valiquette SD, Blackwell HE. Selection of Appropriate Autoinducer Analogues for the Modulation of Quorum Sensing at the Host-Bacterium Interface. ACS Chem Biol 2018; 13:3115-3122. [PMID: 30296049 PMCID: PMC6239973 DOI: 10.1021/acschembio.8b00676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacteria regulate a variety of phenotypes in response to their population density using quorum sensing (QS). This phenomenon is regulated by small molecule or peptide signals, the best characterized of which are the N-acyl l-homoserine lactones (AHLs) utilized by Gram-negative bacteria. As many QS-controlled phenotypes, notably pathogenicity and symbiosis, can profoundly impact host eukaryotes, there is significant interest in developing methods for modulating QS signaling and either ameliorating or augmenting these phenotypes. One strategy has been the use of non-native AHL analogues to agonize or antagonize specific AHL receptors. This approach is complicated, however, by the potential for prospective hosts to respond to both native AHLs and synthetic analogues. Accordingly, identifying AHL analogues with little or no activity toward eukaryotes is important in developing QS modulation as a strategy for the regulation of prokaryotic behaviors. Herein, we utilize the model plant Arabidopsis thaliana to characterize eukaryotic responses to a variety of synthetic AHL analogues to identify structural elements of existing scaffolds that may elicit responses in prospective hosts. Our results indicate that, while many of these compounds have no discernible effect on A. thaliana, some elicit strong phenotypes similar to those produced by auxin, a hormone involved in almost all aspects of plant development. We outline concentrations and chemical scaffolds that are ideal for deployment on plant hosts for the regulation of QS. This approach should be exportable to other eukaryotes for the selection of optimal AHL tools for the study of QS at the host-microbe interface.
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Affiliation(s)
- Andrew G. Palmer
- Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901
| | - Amanda C. Senechal
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706
| | - Timothy C. Haire
- Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901
| | - Nidhi P. Mehta
- Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901
| | - Sara D. Valiquette
- Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706
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41
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Styles MJ, Blackwell HE. Non-native autoinducer analogs capable of modulating the SdiA quorum sensing receptor in Salmonella enterica serovar Typhimurium. Beilstein J Org Chem 2018; 14:2651-2664. [PMID: 30410627 PMCID: PMC6204753 DOI: 10.3762/bjoc.14.243] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/26/2018] [Indexed: 12/19/2022] Open
Abstract
Quorum sensing (QS) allows many common bacterial pathogens to coordinate group behaviors such as virulence factor production, host colonization, and biofilm formation at high population densities. This cell–cell signaling process is regulated by N-acyl L-homoserine lactone (AHL) signals, or autoinducers, and LuxR-type receptors in Gram-negative bacteria. SdiA is an orphan LuxR-type receptor found in Escherichia, Salmonella, Klebsiella, and Enterobacter genera that responds to AHL signals produced by other species and regulates genes involved in several aspects of host colonization. The inhibition of QS using non-native small molecules that target LuxR-type receptors offers a non-biocidal approach for studying, and potentially controlling, virulence in these bacteria. To date, few studies have characterized the features of AHLs and other small molecules capable of SdiA agonism, and no SdiA antagonists have been reported. Herein, we report the screening of a set of AHL analogs to both uncover agonists and antagonists of SdiA and to start to delineate structure–activity relationships (SARs) for SdiA:AHL interactions. Using a cell-based reporter of SdiA in Salmonella enterica serovar Typhimurium, several non-natural SdiA agonists and the first set of SdiA antagonists were identified and characterized. These compounds represent new chemical probes for exploring the mechanisms by which SdiA functions during infection and its role in interspecies interactions. Moreover, as SdiA is highly stable when produced in vitro, these compounds could advance fundamental studies of LuxR-type receptor:ligand interactions that engender both agonism and antagonism.
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Affiliation(s)
- Matthew J Styles
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
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42
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Schütz C, Empting M. Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers. Beilstein J Org Chem 2018; 14:2627-2645. [PMID: 30410625 PMCID: PMC6204780 DOI: 10.3762/bjoc.14.241] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/28/2018] [Indexed: 12/12/2022] Open
Abstract
The Gram-negative opportunistic pathogen Pseudomonas aeruginosa causes severe nosocomial infections. It uses quorum sensing (QS) to regulate and coordinate population-wide group behaviours in the infection process like concerted secretion of virulence factors. One very important signalling network is the Pseudomonas quinolone signal (PQS) QS. With the aim to devise novel and innovative anti-infectives, inhibitors have been designed to address the various potential drug targets present within pqs QS. These range from enzymes within the biosynthesis cascade of the signal molecules PqsABCDE to the receptor of these autoinducers PqsR (MvfR). This review shortly introduces P. aeruginosa and its pathogenicity traits regulated by the pqs system and highlights the published drug discovery efforts providing insights into the compound binding modes if available. Furthermore, suitability of the individual targets for pathoblocker design is discussed.
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Affiliation(s)
- Christian Schütz
- Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Department of Drug Design and Optimization (DDOP), Campus E8.1, 66123 Saarbrücken, Germany.,Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany
| | - Martin Empting
- Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Department of Drug Design and Optimization (DDOP), Campus E8.1, 66123 Saarbrücken, Germany.,Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.,German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Saarbrücken, Germany
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43
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Boursier ME, Moore JD, Heitman KM, Shepardson-Fungairino SP, Combs JB, Koenig LC, Shin D, Brown EC, Nagarajan R, Blackwell HE. Structure-Function Analyses of the N-Butanoyl l-Homoserine Lactone Quorum-Sensing Signal Define Features Critical to Activity in RhlR. ACS Chem Biol 2018; 13:2655-2662. [PMID: 30114353 DOI: 10.1021/acschembio.8b00577] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that coordinates the production of many virulence phenotypes at high population density via quorum sensing (QS). The LuxR-type receptor RhlR plays an important role in the P. aeruginosa QS process, and there is considerable interest in the development of chemical approaches to modulate the activity of this protein. RhlR is activated by a simple, low molecular weight N-acyl l-homoserine lactone signal, N-butanoyll-homoserine lactone (BHL). Despite the emerging prominence of RhlR in QS pathways, there has been limited exploration of the chemical features of the BHL scaffold that are critical to its function. In the current study, we sought to systematically delineate the structure-activity relationships (SARs) driving BHL activity for the first time. A focused library of BHL analogues was designed, synthesized, and evaluated in cell-based reporter gene assays for RhlR agonism and antagonism. These investigations allowed us to define a series of SARs for BHL-type ligands and identify structural motifs critical for both activation and inhibition of the RhlR receptor. Notably, we identified agonists that have ∼10-fold higher potencies in RhlR relative to BHL, are highly selective for RhlR agonism over LasR, and are active in the P. aeruginosa background. These compounds and the SARs reported herein should pave a route toward new chemical strategies to study RhlR in P. aeruginosa.
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Affiliation(s)
- Michelle E. Boursier
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Joseph D. Moore
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Katherine M. Heitman
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Sally P. Shepardson-Fungairino
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Joshua B. Combs
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Lea C. Koenig
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel Shin
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, Idaho 83725, United States
| | - Eric C. Brown
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, Idaho 83725, United States
| | - Rajesh Nagarajan
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, Idaho 83725, United States
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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Mayer C, Muras A, Romero M, López M, Tomás M, Otero A. Multiple Quorum Quenching Enzymes Are Active in the Nosocomial Pathogen Acinetobacter baumannii ATCC17978. Front Cell Infect Microbiol 2018; 8:310. [PMID: 30271754 PMCID: PMC6146095 DOI: 10.3389/fcimb.2018.00310] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/14/2018] [Indexed: 12/24/2022] Open
Abstract
Acinetobacter baumannii presents a typical luxI/luxR quorum sensing (QS) system (abaI/abaR) but the acyl-homoserine lactone (AHL) signal profile and factors controlling the production of QS signals in this species have not been determined yet. A very complex AHL profile was identified for A. baumannii ATCC17978 as well as for A. nosocomialis M2, but only when cultivated under static conditions, suggesting that surface or cell-to-cell contact is involved in the activation of the QS genes. The analysis of A. baumanni clinical isolates revealed a strain-specific AHL profile that was also affected by nutrient availability. The concentration of OHC12-HSL, the major AHL found in A. baumannii ATCC17978, peaked upon stationary-phase establishment and decreases steeply afterwards. Quorum quenching (QQ) activity was found in the cell extracts of A. baumannii ATCC17978, correlating with the disappearance of the AHLs from the culture media, indicating that AHL concentration may be self-regulated in this pathogen. Since QQ activity was observed in strains in which AidA, a novel α/β-hydrolase recently identified in A. baumannii, is not present, we have searched for additional QQ enzymes in A. baumannii ATCC17978. Seven putative AHL-lactonase sequences could be identified in the genome and the QQ activity of 3 of them could be confirmed. At least six of these lactonase sequences are also present in all clinical isolates as well as in A. nosocomialis M2. Surface-associated motility and biofilm formation could be blocked by the exogenous addition of the wide spectrum QQ enzyme Aii20J. The differential regulation of the QQ enzymes in A. baumannii ATCC17978 and the full dependence of important virulence factors on the QS system provides a strong evidence of the importance of the AHL-mediated QS/QQ network in this species.
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Affiliation(s)
- Celia Mayer
- Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Andrea Muras
- Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Manuel Romero
- Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - María López
- Department of Microbiology, Complejo Hospitalario Universitario A Coruña-INIBIC, A Coruña Spain
| | - María Tomás
- Department of Microbiology, Complejo Hospitalario Universitario A Coruña-INIBIC, A Coruña Spain
| | - Ana Otero
- Department of Microbiology and Parasitology, Faculty of Biology-CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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Soukarieh F, Williams P, Stocks MJ, Cámara M. Pseudomonas aeruginosa Quorum Sensing Systems as Drug Discovery Targets: Current Position and Future Perspectives. J Med Chem 2018; 61:10385-10402. [PMID: 29999316 DOI: 10.1021/acs.jmedchem.8b00540] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Antimicrobial resistance (AMR) is a serious threat to public health globally, manifested by the frequent emergence of multidrug resistant pathogens that render current chemotherapy inadequate. Health organizations worldwide have recognized the severity of this crisis and implemented action plans to contain its adverse consequences and prolong the utility of conventional antibiotics. Hence, there is a pressing need for new classes of antibacterial agents with novel modes of action. Quorum sensing (QS), a communication system employed by bacterial populations to coordinate virulence gene expression, is a potential target that has been intensively investigated over the past decade. This Perspective will focus on recent advances in targeting the three main quorum sensing systems ( las, rhl, and pqs) of a major opportunistic human pathogen, Pseudomonas aeruginosa, and will specifically evaluate the medicinal chemistry strategies devised to develop QS inhibitors from a drug discovery perspective.
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Affiliation(s)
- Fadi Soukarieh
- School of Life Sciences, Centre for Biomolecular Sciences , University of Nottingham , Nottingham , NG7 2RD , U.K
| | - Paul Williams
- School of Life Sciences, Centre for Biomolecular Sciences , University of Nottingham , Nottingham , NG7 2RD , U.K
| | - Michael J Stocks
- School of Pharmacy, Centre for Biomolecular Sciences , University of Nottingham , Nottingham , NG7 2RD , U.K
| | - Miguel Cámara
- School of Life Sciences, Centre for Biomolecular Sciences , University of Nottingham , Nottingham , NG7 2RD , U.K
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46
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O'Reilly MC, Dong SH, Rossi FM, Karlen KM, Kumar RS, Nair SK, Blackwell HE. Structural and Biochemical Studies of Non-native Agonists of the LasR Quorum-Sensing Receptor Reveal an L3 Loop "Out" Conformation for LasR. Cell Chem Biol 2018; 25:1128-1139.e3. [PMID: 30033130 DOI: 10.1016/j.chembiol.2018.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 02/27/2018] [Accepted: 06/20/2018] [Indexed: 02/06/2023]
Abstract
Chemical strategies to block quorum sensing (QS) could provide a route to attenuate virulence in bacterial pathogens. Considerable research has focused on this approach in Pseudomonas aeruginosa, which uses the LuxR-type receptor LasR to regulate much of its QS network. Non-native ligands that antagonize LasR have been developed, yet we have little understanding of the mode by which these compounds interact with LasR and alter its function, as the receptor is unstable in their presence. Herein, we report an approach to circumvent this challenge through the study of a series of synthetic LasR agonists with varying levels of potency. Structural investigations of these ligands with the LasR ligand-binding domain reveal that certain agonists can enforce a conformation that deviates from that observed for other, often more potent agonists. These results, when combined with cell-based and biophysical analyses, suggest a functional model for LasR that could guide future ligand design.
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Affiliation(s)
- Matthew C O'Reilly
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Shi-Hui Dong
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA
| | - Francis M Rossi
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Kaleigh M Karlen
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Rohan S Kumar
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Satish K Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA.
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
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47
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Brown SP, Blackwell HE, Hammer BK. The State of the Union Is Strong: a Review of ASM's 6th Conference on Cell-Cell Communication in Bacteria. J Bacteriol 2018; 200:e00291-18. [PMID: 29760210 PMCID: PMC6018360 DOI: 10.1128/jb.00291-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 6th American Society for Microbiology Conference on Cell-Cell Communication in Bacteria convened from 16 to 19 October 2017 in Athens, GA. In this minireview, we highlight some of the research presented at that meeting that addresses central questions emerging in the field, including the following questions. How are cell-cell communication circuits designed to generate responses? Where are bacteria communicating? Finally, why are bacteria engaging in such behaviors?
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Affiliation(s)
- Sam P Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Brian K Hammer
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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48
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Goswami M, Espinasse A, Carlson EE. Disarming the virulence arsenal of Pseudomonas aeruginosa by blocking two-component system signaling. Chem Sci 2018; 9:7332-7337. [PMID: 30542536 PMCID: PMC6237130 DOI: 10.1039/c8sc02496k] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 07/06/2018] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas aeruginosa infections have reached a “critical” threat status making novel therapeutic approaches required.
Pseudomonas aeruginosa infections have reached a “critical” threat status making novel therapeutic approaches required. Inhibiting key signaling enzymes known as the histidine kinases (HKs), which are heavily involved with its pathogenicity, has been postulated to be an effective new strategy for treatment. Herein, we demonstrate the potential of this approach with benzothiazole-based HK inhibitors that perturb multiple virulence pathways in the burn wound P. aeruginosa isolate, PA14. Specifically, our compounds significantly reduce the level of toxic metabolites generated by this organism that are involved in quorum-sensing and redox-balancing mechanisms. They also decrease the ability of this organism to swarm and attach to surfaces, likely by influencing their motility appendages. Quantitative transcription analysis of inhibitor-treated cultures showed substantial perturbations to multiple pathways including expression of response regulator GacA, the cognate partner of the “super regulator” of virulence, HK GacS, as well as flagella and pili formation. These promising results establish that blocking of bacterial signaling in P. aeruginosa has dramatic consequences on virulence behaviours, especially in the context of surface-associated infections.
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Affiliation(s)
- Manibarsha Goswami
- Department of Chemistry , University of Minnesota , 225 Pleasant St. SE , Minneapolis , MN 55454 , USA .
| | - Adeline Espinasse
- Department of Chemistry , University of Minnesota , 225 Pleasant St. SE , Minneapolis , MN 55454 , USA .
| | - Erin E Carlson
- Department of Chemistry , University of Minnesota , 225 Pleasant St. SE , Minneapolis , MN 55454 , USA . .,Department of Medicinal Chemistry , University of Minnesota , USA.,Department of Biochemistry, Molecular Biology and Biophysics , University of Minnesota , USA
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49
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Wase N, Black P, DiRusso C. Innovations in improving lipid production: Algal chemical genetics. Prog Lipid Res 2018; 71:101-123. [DOI: 10.1016/j.plipres.2018.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/25/2018] [Accepted: 07/06/2018] [Indexed: 01/01/2023]
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50
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Boursier ME, Manson DE, Combs JB, Blackwell HE. A comparative study of non-native N-acyl l-homoserine lactone analogs in two Pseudomonas aeruginosa quorum sensing receptors that share a common native ligand yet inversely regulate virulence. Bioorg Med Chem 2018; 26:5336-5342. [PMID: 29793752 DOI: 10.1016/j.bmc.2018.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/07/2018] [Accepted: 05/13/2018] [Indexed: 10/16/2022]
Abstract
Certain bacteria can coordinate group behaviors via a chemical communication system known as quorum sensing (QS). Gram-negative bacteria typically use N-acyl l-homoserine lactone (AHL) signals and their cognate intracellular LuxR-type receptors for QS. The opportunistic pathogen Pseudomonas aeruginosa has a relatively complex QS circuit in which two of its LuxR-type receptors, LasR and QscR, are activated by the same natural signal, N-(3-oxo)-dodecanoyl l-homoserine lactone. Intriguingly, once active, LasR activates virulence pathways in P. aeruginosa, while activated QscR can inactivate LasR and thus repress virulence. We have a limited understanding of the structural features of AHLs that engender either agonistic activity in both receptors or receptor-selective activity. Compounds with the latter activity profile could prove especially useful tools to tease out the roles of these two receptors in virulence regulation. A small collection of AHL analogs was assembled and screened in cell-based reporter assays for activity in both LasR and QscR. We identified several structural motifs that bias ligand activation towards each of the two receptors. These findings will inform the development of new synthetic ligands for LasR and QscR with improved potencies and selectivities.
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Affiliation(s)
- Michelle E Boursier
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Daniel E Manson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Joshua B Combs
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI 53706, USA.
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