Thiophenesulfonamides are specific inhibitors of quorum sensing in pathogenic Vibrios

Vibrio bacteria are pathogens of fish, shellfish, coral, and humans due to contaminated seafood consumption. Vibrio virulence factors are controlled by the cell-to-cell communication called quorum sensing, thus this signaling system is a promising target for therapeutic design. We screened a compound library and identified nine compounds, including several 2-thiophenesulfonamides, that inhibit the master quorum sensing transcription factor LuxR in Vibrio campbellii but do not affect cell growth. We synthesized a panel of 50 thiophenesulfonamide compounds to examine the structure-activity relationship effects on quorum sensing in vivo. The most potent molecule identified, PTSP (3-phenyl-1-(thiophen-2-ylsulfonyl)-1H-pyrazole), specifically inhibits LuxR homologs in multiple strains of Vibrio vulnificus, Vibrio parahaemolyticus, and V. campbellii with sub-micromolar concentrations. PTSP efficacy is driven by amino acid conservation in the binding pocket, which is accurately predicted using in silico modeling of inhibitors. Our results underscore the potential for developing thiophenesulfonamides as specific quorum sensing-directed treatments for Vibrio infections.

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N-3-Hydroxy Dodecanoyl-DL-homoserine Lactone (OH-dDHL) Triggers Apoptosis of Bone Marrow-Derived Macrophages through the ER- and Mitochondria-Mediated Pathways

International Journal of Molecular Sciences ◽

10.3390/ijms22147565 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7565

Author(s):

Kyungho Woo ◽

Dong Ho Kim ◽

Man Hwan Oh ◽

Ho Sung Park ◽

Chul Hee Choi

Keyword(s):

Bone Marrow ◽

Quorum Sensing ◽

Deletion Mutant ◽

Transmembrane Protein ◽

Cell Communication ◽

Homoserine Lactone ◽

Host Responses ◽

Wild Type ◽

Mutant Strains

Quorum sensing of Acinetobacter nosocomialis for cell-to-cell communication produces N-3-hydroxy dodecanoyl-DL-homoserine lactone (OH-dDHL) by an AnoR/I two-component system. However, OH-dDHL-driven apoptotic mechanisms in hosts have not been clearly defined. Here, we investigated the induction of apoptosis signaling pathways in bone marrow-derived macrophages treated with synthetic OH-dDHL. Moreover, the quorum-sensing system for virulence regulation was evaluated in vivo using wild-type and anoI-deletion mutant strains. OH-dDHL decreased the viability of macrophage and epithelial cells in dose- and time-dependent manners. OH-dDHL induced Ca2+ efflux and caspase-12 activation by ER stress transmembrane protein (IRE1 and ATF6a p50) aggregation and induced mitochondrial dysfunction through reactive oxygen species (ROS) production, which caused cytochrome c to leak. Pretreatment with a pan-caspase inhibitor reduced caspase-3, -8, and -9, which were activated by OH-dDHL. Pro-inflammatory cytokine and paraoxonase-2 (PON2) gene expression were increased by OH-dDHL. We showed that the anoI-deletion mutant strains have less intracellular invasion compared to the wild-type strain, and their virulence, such as colonization and dissemination, was decreased in vivo. Consequently, these findings revealed that OH-dDHL, as a virulence factor, contributes to bacterial infection and survival as well as the modification of host responses in the early stages of infection.

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Pseudomonas aeruginosa tolerance to tobramycin, hydrogen peroxide and polymorphonuclear leukocytes is quorum-sensing dependent

Microbiology ◽

10.1099/mic.0.27463-0 ◽

2005 ◽

Vol 151 (2) ◽

pp. 373-383 ◽

Cited By ~ 312

Author(s):

Thomas Bjarnsholt ◽

Peter Østrup Jensen ◽

Mette Burmølle ◽

Morten Hentzer ◽

Janus A. J. Haagensen ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Polymorphonuclear Leukocytes ◽

Present Report ◽

Cell Communication ◽

A Cell ◽

Opportunistic Human Pathogen ◽

Conventional Antibiotics

The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis (CF) patients. P. aeruginosa colonizes the CF lungs by forming biofilm structures in the alveoli. In the biofilm mode of growth the bacteria are highly tolerant to otherwise lethal doses of antibiotics and are protected from bactericidal activity of polymorphonuclear leukocytes (PMNs). P. aeruginosa controls the expression of many of its virulence factors by means of a cell–cell communication system termed quorum sensing (QS). In the present report it is demonstrated that biofilm bacteria in which QS is blocked either by mutation or by administration of QS inhibitory drugs are sensitive to treatment with tobramycin and H2O2, and are readily phagocytosed by PMNs, in contrast to bacteria with functional QS systems. In contrast to the wild-type, QS-deficient biofilms led to an immediate respiratory-burst activation of the PMNs in vitro. In vivo QS-deficient mutants provoked a higher degree of inflammation. It is suggested that quorum signals and QS-inhibitory drugs play direct and opposite roles in this process. Consequently, the faster and highly efficient clearance of QS-deficient bacteria in vivo is probably a two-sided phenomenon: down regulation of virulence and activation of the innate immune system. These data also suggest that a combination of the action of PMNs and QS inhibitors along with conventional antibiotics would eliminate the biofilm-forming bacteria before a chronic infection is established.

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Quorum-quenching microbial infections: mechanisms and implications

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2007.2045 ◽

2007 ◽

Vol 362 (1483) ◽

pp. 1201-1211 ◽

Cited By ~ 207

Author(s):

Yi-Hu Dong ◽

Lian-Hui Wang ◽

Lian-Hui Zhang

Keyword(s):

Quorum Sensing ◽

Mammalian Species ◽

Cell Communication ◽

Quorum Quenching ◽

Past Century ◽

The Past ◽

Microbial Infections ◽

Quenching Mechanisms ◽

Conventional Antibiotics

The discovery of antibiotics early in the past century marked the beginning of active control and prevention of infectious microbial diseases. However, extensive use of antibiotics has also unavoidably resulted in the emergence of ‘superbugs’ that resist conventional antibiotics. The finding that many pathogens rely on cell-to-cell communication mechanisms, known as quorum sensing, to synchronize microbial activities essential for infection and survival in the host suggests a promising disease control strategy, i.e. quenching microbial quorum sensing or in short, quorum quenching. Work over the past few years has demonstrated that quorum-quenching mechanisms are widely conserved in many prokaryotic and eukaryotic organisms. These naturally occurring quorum-quenching mechanisms appear to play important roles in microbe–microbe and pathogen–host interactions and have been used, or served as lead compounds, in developing and formulating a new generation of antimicrobials. Characterization of the crystal structures of several types of quorum-quenching enzymes has provided valuable information to elucidate the catalytic mechanisms, as well as clues for future protein tailoring and molecular improvement. The discovery of quorum-sensing signal degradation enzymes in mammalian species represents a new milestone in quorum sensing and quorum quenching research. The finding highlights the importance of investigating their roles in host innate defence against infectious diseases and to determine the factors influencing their in vivo concentrations and catalytic activities.

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Review: Inhibition of bacterial quorum sensing by plant extracts

Israel Journal of Plant Sciences ◽

10.1080/07929978.2015.1067076 ◽

2015 ◽

Vol 62 (4) ◽

pp. 294-297 ◽

Cited By ~ 2

Author(s):

Ludmila Yarmolinsky ◽

Moshe Bronstein ◽

Jonathan Gorelick

Keyword(s):

Quorum Sensing ◽

Medicinal Plants ◽

Cell Communication ◽

Antibiotic Development ◽

Promising Target ◽

Microbial Infections ◽

Bacterial Quorum Sensing ◽

The Face ◽

Bacterial Quorum ◽

New Treatments

Bacterial quorum sensing (QS) is a form of cell-to-cell communication which is vital to the pathogenicity of many bacteria, and therefore a promising target for the development of new treatments for microbial infections. While many medicinal plants possess antibacterial activity, only a few plants have been shown to target quorum sensing. In the face of increased microbial resistance to existing antibiotics coupled with the decline in novel antibiotic development, QS inhibitors from medicinal plants is a promising direction for new antibacterial treatments,. The purpose of this review is to summarize the verified data on the anti-QS properties of medicinal plants and the various mechanisms of their actions.

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Diversity in Natural Transformation Frequencies and Regulation across Vibrio Species

mBio ◽

10.1128/mbio.02788-19 ◽

2019 ◽

Vol 10 (6) ◽

Cited By ~ 7

Author(s):

Chelsea A. Simpson ◽

Ram Podicheti ◽

Douglas B. Rusch ◽

Ankur B. Dalia ◽

Julia C. van Kessel

Keyword(s):

Quorum Sensing ◽

Dna Sequences ◽

Vibrio Vulnificus ◽

Natural Transformation ◽

Ectopic Expression ◽

Transformation Frequency ◽

Content Type ◽

Competence Gene ◽

Regulatory Systems ◽

Vibrio Campbellii

ABSTRACT In Vibrio species, chitin-induced natural transformation enables bacteria to take up DNA from the external environment and integrate it into their genome. Expression of the master competence regulator TfoX bypasses the need for chitin induction and drives expression of the genes required for competence in several Vibrio species. Here, we show that TfoX expression in Vibrio campbellii strains DS40M4 and NBRC 15631 enables high natural transformation frequencies. Conversely, transformation was not achieved in the model quorum-sensing strain V. campbellii BB120 (previously classified as Vibrio harveyi). Surprisingly, we find that quorum sensing is not required for transformation in V. campbellii DS40M4 or Vibrio parahaemolyticus in contrast to the established regulatory pathway in Vibrio cholerae in which quorum sensing is required to activate the competence regulator QstR. Similar to V. cholerae, expression of both QstR and TfoX is necessary for transformation in DS40M4. There is a wide disparity in transformation frequencies among even closely related Vibrio strains, with V. vulnificus having the lowest functional transformation frequency. Ectopic expression of both TfoX and QstR is sufficient to produce a significant increase in transformation frequency in Vibrio vulnificus. To explore differences in competence regulation, we used previously studied V. cholerae competence genes to inform a comparative genomics analysis coupled with transcriptomics. We find that transformation capability cannot necessarily be predicted by the level of gene conservation but rather correlates with competence gene expression following TfoX induction. Thus, we have uncovered notable species- and strain-level variations in the competence gene regulation pathway across the Vibrio genus. IMPORTANCE Naturally transformable, or competent, bacteria are able to take up DNA from their environment, a key method of horizontal gene transfer for acquisition of new DNA sequences. Our research shows that Vibrio species that inhabit marine environments exhibit a wide diversity in natural transformation capability ranging from nontransformability to high transformation rates in which 10% of cells measurably incorporate new DNA. We show that the role of regulatory systems controlling the expression of competence genes (e.g., quorum sensing) differs throughout both the species and strain levels. We explore natural transformation capabilities of Vibrio campbellii species which have been thus far uncharacterized and find novel regulation of competence. Expression of two key transcription factors, TfoX and QstR, is necessary to stimulate high levels of transformation in Vibrio campbellii and recover low rates of transformation in Vibrio vulnificus.

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LuxR Homologue SmcR Is Essential for Vibrio vulnificus Pathogenesis and Biofilm Detachment, and Its Expression is Induced by Host Cells

Infection and Immunity ◽

10.1128/iai.00561-13 ◽

2013 ◽

Vol 81 (10) ◽

pp. 3721-3730 ◽

Cited By ~ 37

Author(s):

Seung Min Kim ◽

Jin Hwan Park ◽

Hyun Sung Lee ◽

Won Bin Kim ◽

Jung Min Ryu ◽

...

Keyword(s):

Quorum Sensing ◽

Vibrio Vulnificus ◽

Cell Communication ◽

Cellular Level ◽

Host Cells ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Content Type ◽

Biofilm Detachment

ABSTRACTQuorum sensing is a cell-to-cell communication system known to control many bacterial processes. In the present study, the functions of quorum sensing in the pathogenesis ofVibrio vulnificus, a food-borne pathogen, were assessed by evaluating the virulence of a mutant deficient in SmcR, a quorum-sensing regulator and homologue of LuxR. When biofilms were used as an inoculum, thesmcRmutant was impaired in virulence and colonization capacity in the infection of mice. The lack of SmcR also resulted in decreased histopathological damage in mouse jejunum tissue. These results indicated that SmcR is essential forV. vulnificuspathogenesis. Moreover, thesmcRmutant exhibited significantly reduced biofilm detachment. Upon exposure to INT-407 host cells, the wild type, but not thesmcRmutant, revealed accelerated biofilm detachment. The INT-407 cells increasedsmcRexpression by activating the expression of LuxS, an autoinducer-2 synthase, indicating that host cells manipulate the cellular level of SmcR through the quorum-sensing signaling ofV. vulnificus. A whole-genome microarray analysis revealed that the genes primarily involved in biofilm detachment and formation are up- and downregulated by SmcR, respectively. Among the SmcR-regulated genes,vvpEencoding an elastolytic protease was the most upregulated, and the purified VvpE appeared to dissolve established biofilms directly in a concentration-dependent mannerin vitro. These results suggest that the host cell-induced SmcR enhances the detachment ofV. vulnificusbiofilms entering the host intestine and thereby may promote the dispersal of the pathogen to new colonization loci, which is crucial for pathogenesis.

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Fungal Quorum-Sensing Molecules: A Review of Their Antifungal Effect against Candida Biofilms

Journal of Fungi ◽

10.3390/jof6030099 ◽

2020 ◽

Vol 6 (3) ◽

pp. 99 ◽

Cited By ~ 1

Author(s):

Renátó Kovács ◽

László Majoros

Keyword(s):

Quorum Sensing ◽

Opposite Effect ◽

Cell Communication ◽

Therapeutic Strategies ◽

Adjuvant Effect ◽

Antifungal Effect ◽

Extracellular Molecules ◽

Novel Therapeutic Strategies

The number of effective therapeutic strategies against biofilms is limited; development of novel therapies is urgently needed to treat a variety of biofilm-associated infections. Quorum sensing is a special form of microbial cell-to-cell communication that is responsible for the release of numerous extracellular molecules, whose concentration is proportional with cell density. Candida-secreted quorum-sensing molecules (i.e., farnesol and tyrosol) have a pivotal role in morphogenesis, biofilm formation, and virulence. Farnesol can mediate the hyphae-to-yeast transition, while tyrosol has the opposite effect of inducing transition from the yeast to hyphal form. A number of questions regarding Candida quorum sensing remain to be addressed; nevertheless, the literature shows that farnesol and tyrosol possess remarkable antifungal and anti-biofilm effect at supraphysiological concentration. Furthermore, previous in vitro and in vivo data suggest that they may have a potent adjuvant effect in combination with certain traditional antifungal agents. This review discusses the most promising farnesol- and tyrosol-based in vitro and in vivo results, which may be a foundation for future development of novel therapeutic strategies to combat Candida biofilms.

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Tocopherol and phytol possess anti-quorum sensing mediated anti-infective behavior against Vibrio campbellii in aquaculture: An in vitro and in vivo study

Microbial Pathogenesis ◽

10.1016/j.micpath.2021.105221 ◽

2021 ◽

Vol 161 ◽

pp. 105221

Author(s):

Rajaiah Alexpandi ◽

Gurusamy Abirami ◽

Lakkakula Satish ◽

Roshni Prithiviraj Swasthikka ◽

Nataraj Krishnaveni ◽

...

Keyword(s):

Quorum Sensing ◽

In Vivo Study ◽

Vibrio Campbellii

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Diversity in natural transformation frequencies and regulation acrossVibriospecies

10.1101/683029 ◽

2019 ◽

Author(s):

Chelsea A. Simpson ◽

Ram Podicheti ◽

Douglas B. Rusch ◽

Ankur B. Dalia ◽

Julia C. van Kessel

Keyword(s):

Quorum Sensing ◽

Dna Sequences ◽

Vibrio Vulnificus ◽

Natural Transformation ◽

Ectopic Expression ◽

Transformation Frequency ◽

Regulatory Systems ◽

High Transformation ◽

The Difference ◽

Vibrio Campbellii

AbstractIn marineVibriospecies, chitin-induced natural transformation enables bacteria to take up DNA from the external environment and integrate it into their genome via homologous recombination. Expression of the master competence regulator TfoX bypasses the need for chitin induction and drives expression of the genes required for competence in severalVibriospecies. Here, we show that TfoX expression in twoVibrio campbelliistrains, DS40M4 and NBRC 15631, enables high frequencies of natural transformation. Conversely, transformation was not achieved in the model quorum-sensing strainV. campbelliiBB120 (previously classified asVibrio harveyi). Surprisingly, we find that quorum sensing is not required for transformation inV. campbelliiDS40M4. This result is in contrast toVibrio choleraethat requires the quorum-sensing regulator HapR to activate the competence regulator QstR. However, similar toV. cholerae, QstR is necessary for transformation in DS40M4. To investigate the difference in transformation frequencies between BB120 and DS40M4, we used previously studiedV. choleraecompetence genes to inform a comparative genomics analysis coupled with transcriptomics. BB120 encodes homologs of all known competence genes, but most of these genes were not induced by ectopic expression of TfoX, which likely accounts for the non-functional natural transformation in this strain. Comparison of transformation frequencies amongVibriospecies indicates a wide disparity among even closely related strains, withVibrio vulnificushaving the lowest functional transformation frequency. We show that ectopic expression of both TfoX and QstR is sufficient to produce a significant increase in transformation frequency inVibrio vulnificus.SignificanceNaturally transformable or competent bacteria are able to take up DNA from their environment, a key method of horizontal gene transfer for acquisition of new DNA sequences. Our research shows thatVibriospecies that inhabit marine environments exhibit a wide diversity in natural transformation capability ranging from non-transformable to high transformation rates in which 10% of cells measurably incorporate new DNA. We show that the role of regulatory systems controlling the expression of competence genes (e.g., quorum sensing) is conserved among closely related species but differs throughout the genus. Expression of two key transcription factors, TfoX and QstR, are necessary and sufficient to stimulate high levels of transformation inVibrio campbelliiand recover low rates of transformation inVibrio vulnificus.

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LuxR Solos from Environmental Fluorescent Pseudomonads

mSphere ◽

10.1128/msphere.01322-20 ◽

2021 ◽

Vol 6 (2) ◽

Author(s):

Cristina Bez ◽

Sonia Covaceuzach ◽

Iris Bertani ◽

Kumari Sonal Choudhary ◽

Vittorio Venturi

Keyword(s):

Quorum Sensing ◽

Cell Signaling ◽

Communication Networks ◽

Cell Communication ◽

Binding Pocket ◽

Homoserine Lactone ◽

Fluorescent Pseudomonads ◽

Content Type ◽

Gene Expression Studies ◽

Cell Cell

ABSTRACT LuxR solos are related to quorum sensing (QS) LuxR family regulators; however, they lack a cognate LuxI family protein. LuxR solos are widespread and almost exclusively found in proteobacteria. In this study, we investigated the distribution and conservation of LuxR solos in the fluorescent pseudomonads group. Our analysis of more than 600 genomes revealed that the majority of fluorescent Pseudomonas spp. carry one or more LuxR solos, occurring considerably more frequently than complete LuxI/LuxR archetypical QS systems. Based on the adjacent gene context and conservation of the primary structure, nine subgroups of LuxR solos have been identified that are likely to be involved in the establishment of communication networks. Modeling analysis revealed that the majority of subgroups shows some substitutions at the invariant amino acids of the ligand-binding pocket of QS LuxRs, raising the possibility of binding to non-acyl-homoserine lactone (AHL) ligands. Several mutants and gene expression studies on some LuxR solos belonging to different subgroups were performed in order to shed light on their response. The commonality of LuxR solos among fluorescent pseudomonads is an indication of their important role in cell-cell signaling. IMPORTANCE Cell-cell communication in bacteria is being extensively studied in simple settings and uses chemical signals and cognate regulators/receptors. Many Gram-negative proteobacteria use acyl-homoserine lactones (AHLs) synthesized by LuxI family proteins and cognate LuxR-type receptors to regulate their quorum sensing (QS) target loci. AHL-QS circuits are the best studied QS systems; however, many proteobacterial genomes also contain one or more LuxR solos, which are QS-related LuxR proteins which are unpaired to a cognate LuxI. A few LuxR solos have been implicated in intraspecies, interspecies, and interkingdom signaling. Here, we report that LuxR solo homologs occur considerably more frequently than complete LuxI/LuxR QS systems within the Pseudomonas fluorescens group of species and that they are characterized by different genomic organizations and primary structures and can be subdivided into several subgroups. The P. fluorescens group consists of more than 50 species, many of which are found in plant-associated environments. The role of LuxR solos in cell-cell signaling in fluorescent pseudomonads is discussed.

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