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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Woods KE, Akhter S, Rodriguez B, Townsend KA, Smith N, Smith B, Wambua A, Craddock V, Abisado-Duque RG, Santa EE, Manson DE, Oakley BR, Hancock LE, Miao Y, Blackwell HE, Chandler JR. Characterization of natural product inhibitors of quorum sensing in Pseudomonas aeruginosa reveals competitive inhibition of RhlR by ortho-vanillin. bioRxiv 2024:2024.02.24.581676. [PMID: 38559250 PMCID: PMC10979890 DOI: 10.1101/2024.02.24.581676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Quorum sensing (QS) is a cell-cell signaling system that enables bacteria to coordinate population density-dependent changes in behavior. This chemical communication pathway is mediated by diffusible N-acyl L-homoserine lactone signals and cytoplasmic signal-responsive LuxR-type receptors in Gram-negative bacteria. As many common pathogenic bacteria use QS to regulate virulence, there is significant interest in disrupting QS as a potential therapeutic strategy. Prior studies have implicated the natural products salicylic acid, cinnamaldehyde and other related benzaldehyde derivatives as inhibitors of QS in the opportunistic pathogen Pseudomonas aeruginosa, yet we lack an understanding of the mechanisms by which these compounds function. Herein, we evaluate the activity of a set of benzaldehyde derivatives using heterologous reporters of the P. aeruginosa LasR and RhlR QS signal receptors. We find that most tested benzaldehyde derivatives can antagonize LasR or RhlR reporter activation at micromolar concentrations, although certain molecules also caused mild growth defects and nonspecific reporter antagonism. Notably, several compounds showed promising RhlR or LasR specific inhibitory activities over a range of concentrations below that causing toxicity. Ortho-Vanillin, a previously untested compound, was the most promising within this set. Competition experiments against the native ligands for LasR and RhlR revealed that ortho-vanillin can interact competitively with RhlR but not with LasR. Overall, these studies expand our understanding of benzaldehyde activities in the LasR and RhlR receptors and reveal potentially promising effects of ortho-vanillin as a small molecule QS modulator against RhlR.
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Affiliation(s)
- Kathryn E. Woods
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Sana Akhter
- Center for Computational Biology, University of Kansas, Lawrence, KS 66045
| | - Blanca Rodriguez
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Kade A. Townsend
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Nathan Smith
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Ben Smith
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Alice Wambua
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Vaughn Craddock
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | | | - Emma E. Santa
- Department of Chemistry, University of Wisconsin–Madison, Madison, WI 53706
| | - Daniel E. Manson
- Department of Chemistry, University of Wisconsin–Madison, Madison, WI 53706
| | - Berl R. Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Lynn E. Hancock
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Yinglong Miao
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
- Center for Computational Biology, University of Kansas, Lawrence, KS 66045
- Current location: Department of Pharmacology and Computational Medicine Program, University of North Carolina–Chapel Hill, Chapel Hill, NC 27599
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin–Madison, Madison, WI 53706
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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