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Durante-Rodríguez G, de Francisco-Polanco S, García JL, Díaz E. Characterization of a MHYT domain-coupled transcriptional regulator that responds to carbon monoxide. Nucleic Acids Res 2024:gkae575. [PMID: 38966994 DOI: 10.1093/nar/gkae575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/11/2024] [Accepted: 06/25/2024] [Indexed: 07/06/2024] Open
Abstract
The MHYT domain, identified over two decades ago for its potential to detect diatomic gases like CO, O2 or NO, has awaited experimental validation as a protein sensory domain. Here, we characterize the MHYT domain-containing transcriptional regulator CoxC, which governs the expression of the cox genes responsible for aerobic CO oxidation in the carboxidotrophic bacterium Afipia carboxidovorans OM5. The C-terminal LytTR-type DNA-binding domain of CoxC binds to an operator region consisting of three direct repeats sequences overlapping the -35 box at the target PcoxB promoter, which is consistent with the role of CoxC as a specific transcriptional repressor of the cox genes. Notably, the N-terminal transmembrane MHYT domain endows CoxC with the ability to sense CO as an effector molecule, as demonstrated by the relief of CoxC-mediated repression and binding to the PcoxB promoter upon CO exposure. Furthermore, copper serves as the essential divalent cation for the interaction of CO with CoxC, thereby confirming previous hypothesis regarding the role of copper in the gas-sensing mechanism of MHYT domains. CoxC represents the prototype of a novel subfamily of single-component LytTR transcriptional regulators, characterized by the fusion of a DNA-binding domain with a membrane-bound MHYT sensor domain.
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Affiliation(s)
- Gonzalo Durante-Rodríguez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas Margarita Salas-CSIC, Calle Ramiro de Maeztu, 9, 28040 Madrid. Spain
| | - Sofía de Francisco-Polanco
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas Margarita Salas-CSIC, Calle Ramiro de Maeztu, 9, 28040 Madrid. Spain
| | - José Luis García
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas Margarita Salas-CSIC, Calle Ramiro de Maeztu, 9, 28040 Madrid. Spain
| | - Eduardo Díaz
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas Margarita Salas-CSIC, Calle Ramiro de Maeztu, 9, 28040 Madrid. Spain
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2
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Ali L, Abdel Aziz MH. Crosstalk involving two-component systems in Staphylococcus aureus signaling networks. J Bacteriol 2024; 206:e0041823. [PMID: 38456702 PMCID: PMC11025333 DOI: 10.1128/jb.00418-23] [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] [Indexed: 03/09/2024] Open
Abstract
Staphylococcus aureus poses a serious global threat to human health due to its pathogenic nature, adaptation to environmental stress, high virulence, and the prevalence of antimicrobial resistance. The signaling network in S. aureus coordinates and integrates various internal and external inputs and stimuli to adapt and formulate a response to the environment. Two-component systems (TCSs) of S. aureus play a central role in this network where surface-expressed histidine kinases (HKs) receive and relay external signals to their cognate response regulators (RRs). Despite the purported high fidelity of signaling, crosstalk within TCSs, between HK and non-cognate RR, and between TCSs and other systems has been detected widely in bacteria. The examples of crosstalk in S. aureus are very limited, and there needs to be more understanding of its molecular recognition mechanisms, although some crosstalk can be inferred from similar bacterial systems that share structural similarities. Understanding the cellular processes mediated by this crosstalk and how it alters signaling, especially under stress conditions, may help decipher the emergence of antibiotic resistance. This review highlights examples of signaling crosstalk in bacteria in general and S. aureus in particular, as well as the effect of TCS mutations on signaling and crosstalk.
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Affiliation(s)
- Liaqat Ali
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - May H. Abdel Aziz
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
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3
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Yamaguchi J, Manome T, Hara Y, Yamazaki Y, Nakamura Y, Ishibashi M, Takaya A. Physalin H, physalin B, and isophysalin B suppress the quorum-sensing function of Staphylococcus aureus by binding to AgrA. Front Pharmacol 2024; 15:1365815. [PMID: 38659576 PMCID: PMC11039898 DOI: 10.3389/fphar.2024.1365815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The virulence of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), depends on the expression of toxins and virulence factors controlled by the quorum-sensing (QS) system, encoded on the virulence accessory gene regulator (agr) locus. The aim of this study was to identify a phytochemical that inhibits Agr-QS function and to elucidate its mechanism. We screened 577 compounds and identified physalin H, physalin B, and isophysalin B--phytochemicals belonging to physalins found in plants of the Solanaceae family--as novel Agr-QS modulators. Biological analyses and in vitro protein-DNA binding assays suggested that these physalins suppress gene expression related to the Agr-QS system by inhibiting binding of the key response regulator AgrA to the agr promoters, reducing the function of hemolytic toxins downstream of these genes in MRSA. Furthermore, although physalin F suppressed gene expression in the Agr-QS system, its anti-hemolytic activity was lower than that of physalins H, B, and isophysalin B. Conversely, five physalins isolated from the same plant with the ability to suppress Agr-QS did not reduce bacterial Agr-QS activity but inhibited AgrA binding to DNA in vitro. A docking simulation revealed that physalin interacts with the DNA-binding site of AgrA in three docking states. The carbonyl oxygens at C-1 and C-18 of physalins, which can suppress Agr-QS, were directed to residues N201 and R198 of AgrA, respectively, whereas these carbonyl oxygens of physalins, without Agr-QS suppression activity, were oriented in different directions. Next, 100-ns molecular dynamics simulations revealed that the hydrogen bond formed between the carbonyl oxygen at C-15 of physalins and L186 of AgrA functions as an anchor, sustaining the interaction between the carbonyl oxygen at C-1 of physalins and N201 of AgrA. Thus, these results suggest that physalin H, physalin B, and isophysalin B inhibit the interaction of AgrA with the agr promoters by binding to the DNA-binding site of AgrA, suppressing the Agr-QS function of S. aureus. Physalins that suppress the Agr-QS function are proposed as potential lead compounds in the anti-virulence strategy for MRSA infections.
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Affiliation(s)
- Junpei Yamaguchi
- Department of Infection Control Science, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Teruhisa Manome
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
- Laboratory of Natural Products Chemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Yasumasa Hara
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
- Faculty of Agriculture, Kagawa University, Takamatsu, Japan
| | - Yuriko Yamazaki
- Cutaneous Allergy and Host Defense, Immunology Frontier Research Center, Osaka University, Osaka, Japan
- Department of Dermatology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yuumi Nakamura
- Cutaneous Allergy and Host Defense, Immunology Frontier Research Center, Osaka University, Osaka, Japan
- Department of Dermatology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Masami Ishibashi
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
- School of Pharmacy at Fukuoka, International University of Health and Welfare, Okawa, Japan
| | - Akiko Takaya
- Department of Infection Control Science, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
- Medical Mycology Research Center, Chiba University, Chiba, Japan
- Plant Molecular Science Center, Chiba University, Chiba, Japan
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4
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Díaz MA, Vega-Hissi EG, Blázquez MA, Alberto MR, Arena ME. Restraining Staphylococcus aureus Virulence Factors and Quorum Sensing through Lactic Acid Bacteria Supernatant Extracts. Antibiotics (Basel) 2024; 13:297. [PMID: 38666973 PMCID: PMC11047364 DOI: 10.3390/antibiotics13040297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 03/19/2024] [Accepted: 03/23/2024] [Indexed: 04/29/2024] Open
Abstract
The escalating prevalence of antibiotic-resistant bacteria poses a grave threat to human health, necessitating the exploration of novel alternatives to conventional antibiotics. This study investigated the impact of extracts derived from the supernatant of four lactic acid bacteria strains on factors contributing to the pathogenicity of three Staphylococcus aureus strains. The study evaluated the influence of lactic acid bacteria supernatant extracts on the growth, biofilm biomass formation, biofilm metabolic activity, and biofilm integrity of the S. aureus strains. Additionally, the impact on virulence factors (hemolysin and coagulase) was examined. Gas chromatography coupled with mass spectrometry was used to identify the bioactive compounds in the extracts, while molecular docking analyses explored potential interactions. Predominantly, the extracts contain eight 2,5-diketopiperazines, which are cyclic forms of peptides. The extracts demonstrated inhibitory effects on biofilm formation, the ability to disrupt mature biofilms, and reduce the biofilm cell metabolic activity of the S. aureus strains. Furthermore, they exhibited the ability to inhibit α-hemolysin production and reduce coagulase activity. An in silico docking analysis reveals promising interactions between 2,5-diketopiperazines and key proteins (SarA and AgrA) in S. aureus, confirming their antivirulence and antibiofilm activities. These findings suggest that 2,5-diketopiperazines could serve as a promising lead compound in the fight against antibiotic-resistant S. aureus.
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Affiliation(s)
- Myriam Anabel Díaz
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), Chacabuco 461, San Miguel de Tucumán CP 4000, Argentina;
| | - Esteban Gabriel Vega-Hissi
- Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO-SL), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Ejército de Los Andes 950, San Luis CP 5700, Argentina;
| | - María Amparo Blázquez
- Departament de Farmacologia, Facultat de Farmàcia i Ciències de l’Alimentació, Universitat de València, Avd. Vicent Andrés Estellés s/n, Burjasot, 46100 Valencia, Spain
| | - María Rosa Alberto
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán (UNT), Ayacucho 471, San Miguel de Tucumán CP 4000, Argentina
- Instituto de Biotecnología Farmacéutica y Alimentaria (INBIOFAL, CONICET-UNT), Avenida Kirchner 1900, San Miguel de Tucumán CP 4000, Argentina
| | - Mario Eduardo Arena
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán (UNT), Ayacucho 471, San Miguel de Tucumán CP 4000, Argentina
- Instituto de Biotecnología Farmacéutica y Alimentaria (INBIOFAL, CONICET-UNT), Avenida Kirchner 1900, San Miguel de Tucumán CP 4000, Argentina
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Qiu J, Gasperotti A, Sisattana N, Zacharias M, Jung K. The LytS-type histidine kinase BtsS is a 7-transmembrane receptor that binds pyruvate. mBio 2023; 14:e0108923. [PMID: 37655896 PMCID: PMC10653868 DOI: 10.1128/mbio.01089-23] [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: 05/02/2023] [Accepted: 07/17/2023] [Indexed: 09/02/2023] Open
Abstract
IMPORTANCE Here, we studied the LytS-type histidine kinase BtsS of E. coli and identified the pyruvate binding site within the membrane-spanning domains. It is a small cavity, and pyruvate forms interactions with the side chains of Arg72, Arg99, Cys110, and Ser113 located in transmembrane helices III, IV, and V, respectively. Our results can serve as a starting point to convert BtsS into a sensor for structurally similar ligands such as lactate, which can be used as biosensor in medicine.
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Affiliation(s)
- Jin Qiu
- Faculty of Biology, Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Ana Gasperotti
- Faculty of Biology, Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Nathalie Sisattana
- Faculty of Biology, Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Martin Zacharias
- Center of Functional Protein Assemblies, Technical University of Munich, Garching, Germany
| | - Kirsten Jung
- Faculty of Biology, Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
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Iobbi V, Parisi V, Bernabè G, De Tommasi N, Bisio A, Brun P. Anti-Biofilm Activity of Carnosic Acid from Salvia rosmarinus against Methicillin-Resistant Staphylococcus aureus. PLANTS (BASEL, SWITZERLAND) 2023; 12:3679. [PMID: 37960038 PMCID: PMC10647425 DOI: 10.3390/plants12213679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/17/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
The Salvia rosmarinus "Eretto Liguria" ecotype was studied as a source of valuable bioactive compounds. LC-MS analysis of the methanolic extract underlined the presence of diterpenoids, triterpenoids, polyphenolic acids, and flavonoids. The anti-virulence activity of carnosic acid along with the other most abundant compounds against methicillin-resistant Staphylococcus aureus (MRSA) was evaluated. Only carnosic acid induced a significant reduction in the expression of agrA and rnaIII genes, which encode the key components of quorum sensing (QS), an intracellular signaling mechanism controlling the virulence of MRSA. At a concentration of 0.05 mg/mL, carnosic acid inhibited biofilm formation by MRSA and the expression of genes involved in toxin production and made MRSA more susceptible to intracellular killing, with no toxic effects on eukaryotic cells. Carnosic acid did not affect biofilm formation by Pseudomonas aeruginosa, a human pathogen that often coexists with MRSA in complex infections. The selected ecotype showed a carnosic acid content of 94.3 ± 4.3 mg/g. In silico analysis highlighted that carnosic acid potentially interacts with the S. aureus AgrA response regulator. Our findings suggest that carnosic acid could be an anti-virulence agent against MRSA infections endowed with a species-specific activity useful in multi-microbial infections.
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Affiliation(s)
- Valeria Iobbi
- Department of Pharmacy, University of Genova, Viale Cembrano 4, 16148 Genova, Italy;
| | - Valentina Parisi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Salerno, Italy; (V.P.); (N.D.T.)
| | - Giulia Bernabè
- Department of Molecular Medicine, University of Padova, Via Gabelli 63, 35121 Padova, Italy; (G.B.); (P.B.)
| | - Nunziatina De Tommasi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Salerno, Italy; (V.P.); (N.D.T.)
| | - Angela Bisio
- Department of Pharmacy, University of Genova, Viale Cembrano 4, 16148 Genova, Italy;
| | - Paola Brun
- Department of Molecular Medicine, University of Padova, Via Gabelli 63, 35121 Padova, Italy; (G.B.); (P.B.)
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Patil RS, Sharma S, Bhaskarwar AV, Nambiar S, Bhat NA, Koppolu MK, Bhukya H. TetR and OmpR family regulators in natural product biosynthesis and resistance. Proteins 2023. [PMID: 37874037 DOI: 10.1002/prot.26621] [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: 05/28/2023] [Revised: 08/30/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023]
Abstract
This article provides a comprehensive review and sequence-structure analysis of transcription regulator (TR) families, TetR and OmpR/PhoB, involved in specialized secondary metabolite (SSM) biosynthesis and resistance. Transcription regulation is a fundamental process, playing a crucial role in orchestrating gene expression to confer a survival advantage in response to frequent environmental stress conditions. This process, coupled with signal sensing, enables bacteria to respond to a diverse range of intra and extracellular signals. Thus, major bacterial signaling systems use a receptor domain to sense chemical stimuli along with an output domain responsible for transcription regulation through DNA-binding. Sensory and output domains on a single polypeptide chain (one component system, OCS) allow response to stimuli by allostery, that is, DNA-binding affinity modulation upon signal presence/absence. On the other hand, two component systems (TCSs) allow cross-talk between the sensory and output domains as they are disjoint and transmit information by phosphorelay to mount a response. In both cases, however, TRs play a central role. Biosynthesis of SSMs, which includes antibiotics, is heavily regulated by TRs as it diverts the cell's resources towards the production of these expendable compounds, which also have clinical applications. These TRs have evolved to relay information across specific signals and target genes, thus providing a rich source of unique mechanisms to explore towards addressing the rapid escalation in antimicrobial resistance (AMR). Here, we focus on the TetR and OmpR family TRs, which belong to OCS and TCS, respectively. These TR families are well-known examples of regulators in secondary metabolism and are ubiquitous across different bacteria, as they also participate in a myriad of cellular processes apart from SSM biosynthesis and resistance. As a result, these families exhibit higher sequence divergence, which is also evident from our bioinformatic analysis of 158 389 and 77 437 sequences from TetR and OmpR family TRs, respectively. The analysis of both sequence and structure allowed us to identify novel motifs in addition to the known motifs responsible for TR function and its structural integrity. Understanding the diverse mechanisms employed by these TRs is essential for unraveling the biosynthesis of SSMs. This can also help exploit their regulatory role in biosynthesis for significant pharmaceutical, agricultural, and industrial applications.
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Affiliation(s)
- Rachit S Patil
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Siddhant Sharma
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Aditya V Bhaskarwar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Souparnika Nambiar
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Niharika A Bhat
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Mani Kanta Koppolu
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
| | - Hussain Bhukya
- Department of Biology, Indian Institute of Science Education and Research, Tirupati, India
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Rubio-Mendoza D, Martínez-Meléndez A, Maldonado-Garza HJ, Córdova-Fletes C, Garza-González E. Review of the Impact of Biofilm Formation on Recurrent Clostridioides difficile Infection. Microorganisms 2023; 11:2525. [PMID: 37894183 PMCID: PMC10609348 DOI: 10.3390/microorganisms11102525] [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: 09/05/2023] [Revised: 09/25/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
Clostridioides difficile infection (CDI) may recur in approximately 10-30% of patients, and the risk of recurrence increases with each successive recurrence, reaching up to 65%. C. difficile can form biofilm with approximately 20% of the bacterial genome expressed differently between biofilm and planktonic cells. Biofilm plays several roles that may favor recurrence; for example, it may act as a reservoir of spores, protect the vegetative cells from the activity of antibiotics, and favor the formation of persistent cells. Moreover, the expression of several virulence genes, including TcdA and TcdB toxins, has been associated with recurrence. Several systems and structures associated with adhesion and biofilm formation have been studied in C. difficile, including cell-wall proteins, quorum sensing (including LuxS and Agr), Cyclic di-GMP, type IV pili, and flagella. Most antibiotics recommended for the treatment of CDI do not have activity on spores and do not eliminate biofilm. Therapeutic failure in R-CDI has been associated with the inadequate concentration of drugs in the intestinal tract and the antibiotic resistance of a biofilm. This makes it challenging to eradicate C. difficile in the intestine, complicating antibacterial therapies and allowing non-eliminated spores to remain in the biofilm, increasing the risk of recurrence. In this review, we examine the role of biofilm on recurrence and the challenges of treating CDI when the bacteria form a biofilm.
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Affiliation(s)
- Daira Rubio-Mendoza
- Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey 64460, Mexico; (D.R.-M.); (H.J.M.-G.); (C.C.-F.)
| | - Adrián Martínez-Meléndez
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza 66455, Mexico;
| | - Héctor Jesús Maldonado-Garza
- Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey 64460, Mexico; (D.R.-M.); (H.J.M.-G.); (C.C.-F.)
| | - Carlos Córdova-Fletes
- Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey 64460, Mexico; (D.R.-M.); (H.J.M.-G.); (C.C.-F.)
| | - Elvira Garza-González
- Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey 64460, Mexico; (D.R.-M.); (H.J.M.-G.); (C.C.-F.)
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Williams P, Hill P, Bonev B, Chan WC. Quorum-sensing, intra- and inter-species competition in the staphylococci. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001381. [PMID: 37578829 PMCID: PMC10482373 DOI: 10.1099/mic.0.001381] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/31/2023] [Indexed: 08/15/2023]
Abstract
In Gram-positive bacteria such as Staphylococcus aureus and the coagulase-negative staphylococci (CoNS), the accessory gene regulator (agr) is a highly conserved but polymorphic quorum-sensing system involved in colonization, virulence and biofilm development. Signalling via agr depends on the interaction of an autoinducing peptide (AIP) with AgrC, a transmembrane sensor kinase that, once phosphorylated activates the response regulator AgrA. This in turn autoinduces AIP biosynthesis and drives target gene expression directly via AgrA or via the post-transcriptional regulator, RNAIII. In this review we describe the molecular mechanisms underlying the agr-mediated generation of, and response to, AIPs and the molecular basis of AIP-dependent activation and inhibition of AgrC. How the environment impacts on agr functionality is considered and the consequences of agr dysfunction for infection explored. We also discuss the concept of AIP-driven competitive interference between S. aureus and the CoNS and its anti-infective potential.
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Affiliation(s)
- Paul Williams
- Biodiscovery Institute and School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Phil Hill
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough, LE12 5RD, UK
| | - Boyan Bonev
- Biodiscovery Institute and School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Weng C. Chan
- School of Pharmacy, Biodiscovery Institute, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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10
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Jiang X, Kang R, Yu T, Jiang X, Chen H, Zhang Y, Li Y, Wang H. Cinnamaldehyde Targets the LytTR DNA-Binding Domain of the Response Regulator AgrA to Attenuate Biofilm Formation of Listeria monocytogenes. Microbiol Spectr 2023; 11:e0030023. [PMID: 37140461 PMCID: PMC10269664 DOI: 10.1128/spectrum.00300-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 04/19/2023] [Indexed: 05/05/2023] Open
Abstract
The Agr quorum sensing (QS) system is known to contribute to biofilm formation in Listeria monocytogenes. Cinnamaldehyde, a natural food preservative, is considered an inhibitor of Agr-mediated QS in L. monocytogenes. However, the exact mechanism by which cinnamaldehyde acts on Agr remains unclear. In this study, we assessed the effects of cinnamaldehyde on the histidine kinase AgrC and the response regulator AgrA in the Agr system. AgrC kinase activity was not influenced by cinnamaldehyde, and binding between AgrC and cinnamaldehyde was not observed when microscale thermophoresis (MST) was performed, indicating that AgrC was not the target of cinnamaldehyde. AgrA is specifically bound to the agr promoter (P2) to activate the transcription of the Agr system. However, AgrA-P2 binding was prevented by cinnamaldehyde. The interaction between cinnamaldehyde and AgrA was further confirmed with MST. Two conserved amino acids, Asn-178 and Arg-179, located in the LytTR DNA-binding domain of AgrA, were identified as the key sites for cinnamaldehyde-AgrA binding by alanine mutagenesis and MST. Coincidentally, Asn-178 was also involved in the AgrA-P2 interaction. Taken together, these results suggest that cinnamaldehyde acts as a competitive inhibitor of AgrA in AgrA-P2 binding, which leads to suppressed transcription of the Agr system and reduced biofilm formation in L. monocytogenes. IMPORTANCE Listeria monocytogenes can form biofilms on various food contact surfaces, posing a serious threat to food safety. Biofilm formation of L. monocytogenes is positively regulated by the Agr quorum sensing system. Thus, an alternative strategy for controlling L. monocytogenes biofilms is interfering with the Agr system. Cinnamaldehyde is considered an inhibitor of the L. monocytogenes Agr system; however, its exact mechanism of action is still unclear. Here, we found that AgrA (response regulator), rather than AgrC (histidine kinase), was the target of cinnamaldehyde. The conserved Asn-178 in the LytTR DNA-binding domain of AgrA was involved in cinnamaldehyde-AgrA and AgrA-P2 binding. Therefore, the occupation of Asn-178 by cinnamaldehyde suppressed transcription of the Agr system and reduced biofilm formation in L. monocytogenes. Our findings could provide a better understanding of the mechanism by which cinnamaldehyde inhibits L. monocytogenes biofilm formation.
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Affiliation(s)
- Xiaobing Jiang
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Rui Kang
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Tao Yu
- School of Life Sciences & Basic Medicine, Xinxiang University, Xinxiang, China
- Key Laboratory of Biomedicine and Health Risk Warning of Xinxiang City, Xinxiang, China
| | - Xiaojie Jiang
- School of Life Sciences & Basic Medicine, Xinxiang University, Xinxiang, China
| | - Hong Chen
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Yiping Zhang
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Yi Li
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Hailei Wang
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
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11
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Polaske TJ, West KHJ, Zhao K, Widner DL, York JT, Blackwell HE. Chemical and biomolecular insights into the Staphylococcus aureus agr quorum sensing system: Current progress and ongoing challenges. Isr J Chem 2023; 63:e202200096. [PMID: 38765792 PMCID: PMC11101167 DOI: 10.1002/ijch.202200096] [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: 10/31/2022] [Indexed: 03/19/2023]
Abstract
Staphylococcus aureus is a ubiquitous bacterium that has become a major threat to human health due to its extensive toxin production and tremendous capacity for antibiotic resistance (e.g., MRSA "superbug" infections). Amid a worsening antibiotic resistance crisis, new strategies to combat this deadly microbe that remove the selective pressure of traditional approaches are in high demand. S. aureus utilizes an accessory gene regulator (agr) quorum sensing network to monitor its local cellular population and trigger a devastating communal attack, like an invading horde, once a threshold cell density has been reached. The role of the agr system in a range of disease types is still being unraveled. Herein, we discuss the present-day biochemical understanding of agr along with unresolved details, describe its connection to the progression of infection, and review how chemical strategies have been implemented to study and intercept this signaling pathway. This research is illuminating the potential of agr as an anti-virulence target in S. aureus and should inform the study of similar, yet less studied, agr systems in related bacterial pathogens.
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Affiliation(s)
- Thomas J. Polaske
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Korbin H. J. West
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Ke Zhao
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Danielle L. Widner
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave., Madison, WI 53706 USA
| | - Jordan T. York
- 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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12
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Dent MR, Weaver BR, Roberts MG, Burstyn JN. Carbon Monoxide-Sensing Transcription Factors: Regulators of Microbial Carbon Monoxide Oxidation Pathway Gene Expression. J Bacteriol 2023; 205:e0033222. [PMID: 37154694 PMCID: PMC10210986 DOI: 10.1128/jb.00332-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
Carbon monoxide (CO) serves as a source of energy and carbon for a diverse set of microbes found in anaerobic and aerobic environments. The enzymes that bacteria and archaea use to oxidize CO depend upon complex metallocofactors that require accessory proteins for assembly and proper function. This complexity comes at a high energetic cost and necessitates strict regulation of CO metabolic pathways in facultative CO metabolizers to ensure that gene expression occurs only when CO concentrations and redox conditions are appropriate. In this review, we examine two known heme-dependent transcription factors, CooA and RcoM, that regulate inducible CO metabolism pathways in anaerobic and aerobic microorganisms. We provide an analysis of the known physiological and genomic contexts of these sensors and employ this analysis to contextualize known biochemical properties. In addition, we describe a growing list of putative transcription factors associated with CO metabolism that potentially use cofactors other than heme to sense CO.
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Affiliation(s)
- Matthew R. Dent
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Brian R. Weaver
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Madeleine G. Roberts
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Judith N. Burstyn
- Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin, USA
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13
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Li X, Chen G, Gao QQ, Xiang CF, Yuan CX, Li XN, Shu YY, Zhang GH, Liang YL, Yang SC, Zhai CX, Zhao Y. Site-directed mutagenesis identified the key active site residues of 2,3-oxidosqualene cyclase HcOSC6 responsible for cucurbitacins biosynthesis in Hemsleya chinensis. FRONTIERS IN PLANT SCIENCE 2023; 14:1138893. [PMID: 37056503 PMCID: PMC10086137 DOI: 10.3389/fpls.2023.1138893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/21/2023] [Indexed: 06/19/2023]
Abstract
Hemsleya chinensis is a Chinese traditional medicinal plant, containing cucurbitacin IIa (CuIIa) and cucurbitacin IIb (CuIIb), both of which have a wide range of pharmacological effects, including antiallergic, anti-inflammatory, and anticancer properties. However, few studies have been explored on the key enzymes that are involved in cucurbitacins biosynthesis in H. chinensis. Oxidosqualene cyclase (OSC) is a vital enzyme for cyclizing 2,3-oxidosqualene and its analogues. Here, a gene encoding the oxidosqualene cyclase of H. chinensis (HcOSC6), catalyzing to produce cucurbitadienol, was used as a template of mutagenesis. With the assistance of AlphaFold2 and molecular docking, we have proposed for the first time to our knowledge the 3D structure of HcOSC6 and its binding features to 2,3-oxidosqualene. Mutagenesis experiments on HcOSC6 generated seventeen different single-point mutants, showing that single-residue changes could affect its activity. Three key amino acid residues of HcOSC6, E246, M261 and D490, were identified as a prominent role in controlling cyclization ability. Our findings not only comprehensively characterize three key residues that are potentially useful for producing cucurbitacins, but also provide insights into the significant role they could play in metabolic engineering.
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Affiliation(s)
- Xia Li
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
| | - Geng Chen
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
| | - Qing-Qing Gao
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
| | - Chun-Fan Xiang
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
| | - Cheng-Xiao Yuan
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
| | - Xiao-Ning Li
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
| | - Yan-Yu Shu
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
| | - Guang-Hui Zhang
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
| | - Yan-Li Liang
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
| | - Sheng-Chao Yang
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
| | - Chen-Xi Zhai
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States
| | - Yan Zhao
- Key Laboratory of Medicinal Plant Biology of Yunnan Province, National and Local Joint Engineering Research Center on Germplasms Innovation and Utilization of Chinese Medicinal Materials in Southwest China, Yunnan Agricultural University, Kunming, China
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming, China
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14
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In Vivo Role of Two-Component Regulatory Systems in Models of Urinary Tract Infections. Pathogens 2023; 12:pathogens12010119. [PMID: 36678467 PMCID: PMC9861413 DOI: 10.3390/pathogens12010119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/23/2022] [Accepted: 01/08/2023] [Indexed: 01/12/2023] Open
Abstract
Two-component signaling systems (TCSs) are finely regulated mechanisms by which bacteria adapt to environmental conditions by modifying the expression of target genes. In bacterial pathogenesis, TCSs play important roles in modulating adhesion to mucosal surfaces, resistance to antibiotics, and metabolic adaptation. In the context of urinary tract infections (UTI), one of the most common types infections causing significant health problems worldwide, uropathogens use TCSs for adaptation, survival, and establishment of pathogenicity. For example, uropathogens can exploit TCSs to survive inside bladder epithelial cells, sense osmolar variations in urine, promote their ascension along the urinary tract or even produce lytic enzymes resulting in exfoliation of the urothelium. Despite the usefulness of studying the function of TCSs in in vitro experimental models, it is of primary necessity to study bacterial gene regulation also in the context of host niches, each displaying its own biological, chemical, and physical features. In light of this, the aim of this review is to provide a concise description of several bacterial TCSs, whose activity has been described in mouse models of UTI.
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Huang Y, Qin F, Li S, Yin J, Hu L, Zheng S, He L, Xia H, Liu J, Hu W. The mechanisms of biofilm antibiotic resistance in chronic rhinosinusitis: A review. Medicine (Baltimore) 2022; 101:e32168. [PMID: 36626427 PMCID: PMC9750636 DOI: 10.1097/md.0000000000032168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Chronic rhinosinusitis (CRS) is a common but burdensome ailment that is still poorly understood in terms of its pathogenesis. The existence of biofilms on the sinonasal mucosa of individuals with CRS has been proven by current biofilm identification methods. Current treatments for CRS generally include functional endoscopic sinus surgery, biofilm-removing strategies, and limited therapies that target quorum sensing (QS), patients with CRS are often resistant to antimicrobial therapy at degrees achievable by oral or intravenous administration, and even a subset of patients fail to react to either medical or surgical intervention. Multidrug-resistant Pseudomonas aeruginosa, Staphylococcus aureus, especially methicillin-resistant S. aureus, Streptococcus pneumoniae, and Haemophilus influenzae are the most commonly implicated bacteria in CRS patients, which may lead to the persistence and severity of CRS and antibiotic treatment failure via the formation of biofilms. Resistance to antibiotics is attributed to the 3-dimensional structure and QS of biofilms, and the latter describes the communication of bacteria within biofilms. A better understanding of biofilms in CRS and their contribution to the antibiotic resistance of CRS is critical for novel treatment strategies. This review mainly discusses the special structure of biofilms, QS, and their mechanisms of antibiotic resistance in order to investigate prospective anti-biofilm therapies, suggest future directions for study, and potentially refine the CRS prevention paradigm.
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Affiliation(s)
- Yanlin Huang
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Fengfeng Qin
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Sen Li
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Ji Yin
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Lanxin Hu
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Sihan Zheng
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Lu He
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Hui Xia
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Jing Liu
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Wenjian Hu
- Data sharing not applicable to this article as no datasets were generated or analyzed during the current study. The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
- * Correspondence: Wenjian Hu, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China (e-mail: )
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16
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Inhibition of Staphylococcus aureus Biofilm Formation and Virulence Factor Production by Petroselinic Acid and Other Unsaturated C18 Fatty Acids. Microbiol Spectr 2022; 10:e0133022. [PMID: 35647620 PMCID: PMC9241682 DOI: 10.1128/spectrum.01330-22] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen that secretes several toxins associated with the pathogenesis of sepsis and pneumonia. Its antibiotic resistance is notorious, and its biofilms play a critical role in antibiotic tolerance. We hypothesized fatty acids might inhibit S. aureus biofilm formation and the expressions of its virulence factors. Initially, the antibiofilm activities of 27 fatty acids against a methicillin-sensitive S. aureus strain were investigated. Of the fatty acids tested, three C18 unsaturated fatty acids, that is, petroselinic, vaccenic, and oleic acids at 100 μg/mL, inhibited S. aureus biofilm formation by more than 65% without affecting its planktonic cell growth (MICs were all > 400 μg/mL). Notably, petroselinic acid significantly inhibited biofilm formation of two methicillin-resistant S. aureus strains and two methicillin-sensitive S. aureus strains. In addition, petroselinic acid significantly suppressed the production of three virulence factors, namely, staphyloxanthin, lipase, and α-hemolysin. Transcriptional analysis showed that petroselinic acid repressed the gene expressions of quorum sensing regulator agrA, effector of quorum sensing RNAIII, α-hemolysin hla, nucleases nuc1 and nuc2, and the virulence regulator saeR. Furthermore, petroselinic acid dose-dependently inhibited S. aureus biofilm formation on abiotic surfaces and porcine skin. These findings suggest that fatty acids, particularly petroselinic acid, are potentially useful for controlling biofilm formation by S. aureus. IMPORTANCE Fatty acids with a long carbon chain have recently attracted attention because of their antibiofilm activities against microbes. Here, we report the antibiofilm activities of 27 fatty acids against S. aureus. Of the fatty acids tested, three C18 unsaturated fatty acids (petroselinic, vaccenic, and oleic acids) significantly inhibited biofilm formation by S. aureus. Furthermore, petroselinic acid inhibited the production of several virulence factors in S. aureus. The study also reveals that the action mechanism of petroselinic acid involves repression of quorum-sensing-related and virulence regulator genes. These findings show that natural and nontoxic petroselinic acid has potential use as a treatment for S. aureus infections, including infections by methicillin-resistant S. aureus strains, and in food processing facilities.
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17
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Anti-Quorum Sensing Activities of Gliptins against Pseudomonas aeruginosa and Staphylococcus aureus. Biomedicines 2022; 10:biomedicines10051169. [PMID: 35625906 PMCID: PMC9138634 DOI: 10.3390/biomedicines10051169] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/16/2022] [Accepted: 05/16/2022] [Indexed: 12/24/2022] Open
Abstract
The development of bacterial resistance to traditional antibiotics constitutes an emerging public health issue. Promising approaches have been innovated to conquer bacterial resistance, and targeting bacterial virulence is one of these approaches. Bacterial virulence mitigation offers several merits, as antivirulence agents do not affect the growth of bacteria and hence do not induce bacteria to develop resistance. In this direction, numerous drugs have been repurposed as antivirulence agents prior to their clinical use alone or in combination with traditional antibiotics. Quorum sensing (QS) plays a key role in controlling bacterial virulence. In the current study, dipeptidase inhibitor-4 (DPI-4) antidiabetic gliptins were screened for their antivirulence and anti-quorum sensing (anti-QS) activities against Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. Upon assessing their antibiofilm activities, the ten tested gliptins significantly diminished biofilm formation. In particular, sitagliptin exhibited the most efficient antibiofilm activity, so it was chosen as a representative of all gliptins to further investigate its antivirulence activity. Sitagliptin significantly protected mice from P. aeruginosa and S. aureus pathogenesis. Furthermore, sitagliptin downregulated QS-encoding genes in P. aeruginosa and S. aureus. To test the anti-QS activities of gliptins, a detailed molecular docking study was conducted to evaluate the gliptins’ binding affinities to P. aeruginosa and S. aureus QS receptors, which helped explain the anti-QS activities of gliptins, particularly sitagliptin and omarigliptin. In conclusion, this study evaluates the possible antivirulence and anti-QS activities of gliptins that could be promising novel candidates for the treatment of aggressive Gram-negative or -positive bacterial infections either alone or as adjuvants to other antibiotics.
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18
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Khayat MT, Abbas HA, Ibrahim TS, Khayyat AN, Alharbi M, Darwish KM, Elhady SS, Khafagy ES, Safo MK, Hegazy WAH. Anti-Quorum Sensing Activities of Gliptins against Pseudomonas aeruginosa and Staphylococcus aureus. Biomedicines 2022; 10:1169. [PMID: 35625906 PMCID: PMC9138634 DOI: 10.3389/fmolb.2023.1203672activities 10.3390/biomedicines10051169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/16/2022] [Accepted: 05/16/2022] [Indexed: 07/07/2024] Open
Abstract
The development of bacterial resistance to traditional antibiotics constitutes an emerging public health issue. Promising approaches have been innovated to conquer bacterial resistance, and targeting bacterial virulence is one of these approaches. Bacterial virulence mitigation offers several merits, as antivirulence agents do not affect the growth of bacteria and hence do not induce bacteria to develop resistance. In this direction, numerous drugs have been repurposed as antivirulence agents prior to their clinical use alone or in combination with traditional antibiotics. Quorum sensing (QS) plays a key role in controlling bacterial virulence. In the current study, dipeptidase inhibitor-4 (DPI-4) antidiabetic gliptins were screened for their antivirulence and anti-quorum sensing (anti-QS) activities against Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. Upon assessing their antibiofilm activities, the ten tested gliptins significantly diminished biofilm formation. In particular, sitagliptin exhibited the most efficient antibiofilm activity, so it was chosen as a representative of all gliptins to further investigate its antivirulence activity. Sitagliptin significantly protected mice from P. aeruginosa and S. aureus pathogenesis. Furthermore, sitagliptin downregulated QS-encoding genes in P. aeruginosa and S. aureus. To test the anti-QS activities of gliptins, a detailed molecular docking study was conducted to evaluate the gliptins' binding affinities to P. aeruginosa and S. aureus QS receptors, which helped explain the anti-QS activities of gliptins, particularly sitagliptin and omarigliptin. In conclusion, this study evaluates the possible antivirulence and anti-QS activities of gliptins that could be promising novel candidates for the treatment of aggressive Gram-negative or -positive bacterial infections either alone or as adjuvants to other antibiotics.
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Affiliation(s)
- Maan T. Khayat
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.S.I.); (A.N.K.); (M.A.)
| | - Hisham A. Abbas
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt;
| | - Tarek S. Ibrahim
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.S.I.); (A.N.K.); (M.A.)
| | - Ahdab N. Khayyat
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.S.I.); (A.N.K.); (M.A.)
| | - Majed Alharbi
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (T.S.I.); (A.N.K.); (M.A.)
| | - Khaled M. Darwish
- Department of Medicinal Chemistry, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt;
| | - Sameh S. Elhady
- Department of Natural Products, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
| | - El-Sayed Khafagy
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia;
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Suez Canal University, Ismailia 41552, Egypt
| | - Martin K. Safo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23219, USA;
| | - Wael A. H. Hegazy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt;
- Department of Pharmaceutical Sciences, Pharmacy Program, Oman College of Health Sciences, Muscat 113, Oman
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19
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Dent MR, Roberts MG, Bowman HE, Weaver BR, McCaslin DR, Burstyn JN. Quaternary Structure and Deoxyribonucleic Acid-Binding Properties of the Heme-Dependent, CO-Sensing Transcriptional Regulator PxRcoM. Biochemistry 2022; 61:678-688. [PMID: 35394749 PMCID: PMC11155679 DOI: 10.1021/acs.biochem.2c00086] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
RcoM, a heme-containing, CO-sensing transcription factor, is one of two known bacterial regulators of CO metabolism. Unlike its analogue CooA, the structure and DNA-binding properties of RcoM remain largely uncharacterized. Using a combination of size exclusion chromatography and sedimentation equilibrium, we demonstrate that RcoM-1 from Paraburkholderia xenovorans is a dimer, wherein the heme-binding domain mediates dimerization. Using bioinformatics, we show that RcoM is found in three distinct genomic contexts, in accordance with the previous literature. We propose a refined consensus DNA-binding sequence for RcoM based on sequence alignments of coxM-associated promoters. The RcoM promoter consensus sequence bears two well-conserved direct repeats, consistent with other LytTR domain-containing transcription factors. In addition, there is a third, moderately conserved direct repeat site. Surprisingly, PxRcoM-1 requires all three repeat sites to cooperatively bind DNA with a [P]1/2 of 250 ± 10 nM and an average Hill coefficient, n, of 1.7 ± 0.1. The paralog PxRcoM-2 binds to the same triplet motif with comparable affinity and cooperativity. Considering this unusual DNA binding stoichiometry, that is, a dimeric protein with a triplet DNA repeat-binding site, we hypothesize that RcoM interacts with DNA in a manner distinct from other LytTR domain-containing transcription factors.
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Affiliation(s)
- Matthew R Dent
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Madeleine G Roberts
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Hannah E Bowman
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Brian R Weaver
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Darrell R McCaslin
- Biophysics Instrumentation Facility, Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Judith N Burstyn
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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20
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Bremer E, Hoffmann T, Dempwolff F, Bedrunka P, Bange G. The many faces of the unusual biofilm activator RemA. Bioessays 2022; 44:e2200009. [PMID: 35289951 DOI: 10.1002/bies.202200009] [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: 01/11/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 11/08/2022]
Abstract
Biofilms can be viewed as tissue-like structures in which microorganisms are organized in a spatial and functional sophisticated manner. Biofilm formation requires the orchestration of a highly integrated network of regulatory proteins to establish cell differentiation and production of a complex extracellular matrix. Here, we discuss the role of the essential Bacillus subtilis biofilm activator RemA. Despite intense research on biofilms, RemA is a largely underappreciated regulatory protein. RemA forms donut-shaped octamers with the potential to assemble into dimeric superstructures. The presumed DNA-binding mode suggests that RemA organizes its target DNA into nucleosome-like structures, which are the basis for its role as transcriptional activator. We discuss how RemA affects gene expression in the context of biofilm formation, and its regulatory interplay with established components of the biofilm regulatory network, such as SinR, SinI, SlrR, and SlrA. We emphasize the additional role of RemA played in nitrogen metabolism and osmotic-stress adjustment.
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Affiliation(s)
- Erhard Bremer
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Tamara Hoffmann
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Felix Dempwolff
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Patricia Bedrunka
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany.,Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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21
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Desouky SE, Abu-Elghait M, Fayed EA, Selim S, Yousuf B, Igarashi Y, Abdel-Wahab BA, Mohammed Alsuhaibani A, Sonomoto K, Nakayama J. Secondary Metabolites of Actinomycetales as Potent Quorum Sensing Inhibitors Targeting Gram-Positive Pathogens: In Vitro and In Silico Study. Metabolites 2022; 12:metabo12030246. [PMID: 35323689 PMCID: PMC8955454 DOI: 10.3390/metabo12030246] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 02/07/2023] Open
Abstract
Anti-virulence agents are non-bacteriostatic and non-bactericidal emerging therapeutic options which hamper the production of virulence factors in pathogenic flora. In Staphylococcus aureus and Enterococcus faecalis, regulation of virulence genes’ expression occurs through the cyclic peptide-mediated accessory gene regulator (agr) and its ortholog fsr quorum sensing systems, respectively. In the present study, we screened a set of 54 actinomycetales secondary metabolites as novel anti-virulence compounds targeting quorum sensing system of the Gram-positive bacteria. The results indicated that four compounds, Phenalinolactones A–D, BU–4664LMe, 4,5-dehydrogeldamycin, and Questinomycin A, potentially inhibit the agr quorum sensing system and hemolytic activity of S. aureus. On the other hand, Decatromicin A and B, Okilactomycin, Rishirilide A, Abyssomicin I, and Rebeccamycin selectively blocked the fsr quorum sensing system and the gelatinase production in E. faecalis at sub-lethal concentrations. Interestingly, Synerazol uniquely showed the capability to inhibit both fsr and agr quorum sensing systems. Further, in silico molecular docking studies were performed which provided closer insights into the mode of action of these compounds and proposed that the inhibitory activity of these compounds could be attributed to their potential ability to bind to the ATP-active site of S. aureus AgrA. Taken together, our study highlights the potential of actinomycetales secondary metabolites with diverse structures as anti-virulence quorum sensing inhibitors.
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Affiliation(s)
- Said E. Desouky
- Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt;
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
- Correspondence:
| | - Mohammed Abu-Elghait
- Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt;
| | - Eman A. Fayed
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo 11754, Egypt;
| | - Samy Selim
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 72341, Saudi Arabia;
| | - Basit Yousuf
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
| | - Yasuhiro Igarashi
- Biotechnology Research Center, Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan;
| | - Basel A. Abdel-Wahab
- Department of Medical Pharmacology, College of Medicine, Assiut University, Assiut 7111, Egypt;
- Department of Pharmacology, College of Pharmacy, Najran University, Najran 1988, Saudi Arabia
| | - Amnah Mohammed Alsuhaibani
- Department of Physical Sport Science, College of Education, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia;
| | - Kenji Sonomoto
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
| | - Jiro Nakayama
- Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan; (B.Y.); (K.S.); (J.N.)
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Ahmed UKB, Ballard JD. Autoinducing peptide-based quorum signaling systems in Clostridioides difficile. Curr Opin Microbiol 2022; 65:81-86. [PMID: 34773906 PMCID: PMC8792308 DOI: 10.1016/j.mib.2021.10.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 02/03/2023]
Abstract
The autoinducing peptide-based Agr system in Clostridioides difficile is involved in virulence factor expression, motility, and sporulation. This review highlights several of the recent discoveries regarding C. difficile Agr. Typical Agr systems rely on the combined activities of four proteins involved in peptide expression, peptide processing, peptide sensing, and transcriptional regulation. As emphasized in this review, at least two C. difficile Agr systems (Agr1 and Agr3) lack the set of proteins associated with this regulatory network. In line with this, recent finding indicate Agr1 can function in ways that may not depend on accumulation of extracellular peptide. Also, described are the similarities and differences in Agr systems within the pathogenic Clostridia.
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Expression, Purification, and Characterization of the Recombinant, Two-Component, Response Regulator ArlR from Fusobacterium nucleatum. Appl Biochem Biotechnol 2022; 194:2093-2107. [PMID: 35029789 DOI: 10.1007/s12010-021-03785-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2021] [Indexed: 11/02/2022]
Abstract
Fusobacterium nucleatum is associated with the incidence and development of multiple diseases, such as periodontitis and colorectal cancer (CRC). Until now, studies have proved only a few proteins to be associated with such pathogenic diseases. The two-component system is one of the most prevalent forms of bacterial signal transduction related to intestinal diseases. Here, we report a novel, recombinant, two-component, response regulator protein ArlR from the genome of F. nucleatum strain ATCC 25,586. We optimized the expression and purification conditions of ArlR; in addition, we characterized the interaction of this response regulator protein with the corresponding histidine kinase and DNA sequence. The full-length ArlR was successfully expressed in six E. coli host strains. However, optimum expression conditions of ArlR were present only in E. coli strain BL21 CodonPlus (DE3) RIL that was later induced with isopropyl β-D-1-thiogalactopyranoside (IPTG) for 8 h at 25 °C. The SDS-PAGE analysis revealed the molecular weight of the recombinant protein as 27.3 kDa with approximately 90% purity after gel filtration chromatography. Because ArlR was biologically active after its purification, it accepted the corresponding phosphorylated histidine kinase phosphate group and bound to the analogous DNA sequence. The binding constant between ArlR and the corresponding histidine kinase was about 2.1 μM, whereas the binding constant between ArlR and its operon was 6.4 μM. Altogether, these results illustrate an effective expression and purification method for the novel two-component system protein ArlR.
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24
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Laabei M, Peacock SJ, Blane B, Baines SL, Howden BP, Stinear TP, Massey RC. Significant variability exists in the cytotoxicity of global methicillin-resistant Staphylococcus aureus lineages. MICROBIOLOGY (READING, ENGLAND) 2021; 167. [PMID: 34928202 PMCID: PMC8744995 DOI: 10.1099/mic.0.001119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Staphylococcus aureus is a major human pathogen where the emergence of antibiotic resistant lineages, such as methicillin-resistant S. aureus (MRSA), is a major health concern. While some MRSA lineages are restricted to the healthcare setting, the epidemiology of MRSA is changing globally, with the rise of specific lineages causing disease in healthy people in the community. In the past two decades, community-associated MRSA (CA-MRSA) has emerged as a clinically important and virulent pathogen associated with serious skin and soft-tissue infections (SSTI). These infections are primarily cytotoxin driven, leading to the suggestion that hypervirulent lineages/multi-locus sequence types (STs) exist. To examine this, we compared the cytotoxicity of 475 MRSA isolates representing five major MRSA STs (ST22, ST93, ST8, ST239 and ST36) by employing a monocyte-macrophage THP-1 cell line as a surrogate for measuring gross cytotoxicity. We demonstrate that while certain MRSA STs contain highly toxic isolates, there is such variability within lineages to suggest that this aspect of virulence should not be inferred from the genotype of any given isolate. Furthermore, by interrogating the accessory gene regulator (Agr) sequences in this collection we identified several Agr mutations that were associated with reduced cytotoxicity. Interestingly, the majority of isolates that were attenuated in cytotoxin production contained no mutations in the agr locus, indicating a role of other undefined genes in S. aureus toxin regulation.
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Affiliation(s)
- Maisem Laabei
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
- *Correspondence: Maisem Laabei,
| | - Sharon J. Peacock
- Department of Medicine, Addenbrooke’s Hospital, University of Cambridge, Hills Road, Box 157, Cambridge, CB2 0QQ, UK
| | - Beth Blane
- Department of Medicine, Addenbrooke’s Hospital, University of Cambridge, Hills Road, Box 157, Cambridge, CB2 0QQ, UK
| | - Sarah L. Baines
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Benjamin P. Howden
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Microbiological Diagnostic Unit Public Health Laboratory, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Timothy P. Stinear
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Ruth C. Massey
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, UK
- *Correspondence: Ruth C. Massey,
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El-Ganiny AM, Gad AI, El-Sayed MA, Shaldam MA, Abbas HA. The promising anti-virulence activity of candesartan, domperidone, and miconazole on Staphylococcus aureus. Braz J Microbiol 2021; 53:1-18. [PMID: 34773629 DOI: 10.1007/s42770-021-00655-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 10/17/2021] [Indexed: 12/15/2022] Open
Abstract
Staphylococcus aureus is a primary cause of hospital and community-acquired infections. With the emergence of multidrug-resistant S. aureus strains, there is a need for new drugs discovery. Due to the poor supply of new antimicrobials, targeting virulence of S. aureus may generate weaker selection for resistant strains, anti-virulence agents disarm the pathogen instead of killing it. In this study, the ability of the FDA-approved drugs domperidone, candesartan, and miconazole as inhibitors of S. aureus virulence was investigated. The effect of tested drugs was evaluated against biofilm formation, lipase, protease, hemolysin, and staphyloxanthin production by using phenotypic and genotypic methods. At sub-inhibitory concentrations, candesartan, domperidone, and miconazole showed a significant inhibition of hemolysin (75.8-96%), staphyloxanthin (81.2-85%), lipase (50-65%), protease (40-64%), and biofilm formation (71.4-90%). Domperidone and candesartan have similar activity and were more powerful than miconazole against S. aureus virulence. The hemolysins and lipase inhibition were the greatest under the domperidone effect. Candesartan showed a remarkable reduction in staphyloxanthin production. The highest inhibitory effect of proteolytic activity was obtained with domperidone and candesartan. Biofilm was significantly reduced by miconazole. Expression levels of crtM, sigB, sarA, agrA, hla, fnbA, and icaA genes were significantly reduced under candesartan (68.98-82.7%), domperidone (62.6-77.2%), and miconazole (32.96-52.6%) at sub-MIC concentrations. Candesartan showed the highest inhibition activity against crtM, sigB, sarA, agrA, hla, and icaA expression followed by domperidone then miconazole. Domperidone showed the highest downregulation activity against fnbA gene. In conclusion, candesartan, domperidone, and miconazole could serve as anti-virulence agents for attenuation of S. aureus pathogenicity.
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Affiliation(s)
- Amira M El-Ganiny
- Microbiology and Immunology Department, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Amany I Gad
- Microbiology and Immunology Department, School of Pharmacy and Pharmaceutical Industries, Badr University in Cairo (BUC), Badr City, 11829, Cairo, Egypt.
| | - Mona A El-Sayed
- Microbiology and Immunology Department, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Moataz A Shaldam
- Pharmaceutical Chemistry Department, Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh, 33516, Egypt
| | - Hisham A Abbas
- Microbiology and Immunology Department, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
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Redox Sensing Modulates the Activity of the ComE Response Regulator of Streptococcus mutans. J Bacteriol 2021; 203:e0033021. [PMID: 34516285 DOI: 10.1128/jb.00330-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans, a dental pathogen, encodes the ComDE two-component system comprised of a histidine kinase (ComD) and a response regulator (ComE). This system is necessary for production of bacteriocins and development of genetic competence. ComE interacts with its cognate promoters to activate the transcription of bacteriocin and competence-related genes. Previous transcriptomic studies indicated that expressions of bacteriocin genes were upregulated in the presence of oxygen. To understand the relationship between the aerobic condition and bacteriocin expression, we analyzed the S. mutans ComE sequence and its close homologs. Surprisingly, we noticed the presence of cysteine (Cys) residues located at positions 200 and 229, which are highly conserved among the ComE homologs. Here, we investigated the role of Cys residues of S. mutans ComE in the activation of bacteriocin transcription using the PnlmA promoter that expresses bacteriocin NlmA. We constructed both single mutants and double mutants by replacing the Cys residues with serine and performed complementation assays. We observed that the presence of Cys residues is essential for PnlmA activation. With purified ComE mutant proteins, we found that ComE double mutants displayed a nearly 2-fold lower association rate than wild-type ComE. Furthermore, 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence studies indicated that the double mutants displayed wider conformation changes than wild-type ComE. Finally, we demonstrated that close streptococcal ComE homologs successfully activate the PnlmA expression in vivo. This is the first report suggesting that S. mutans ComE and its homologs can sense the oxidation status of the cell, a phenomenon similar to the AgrA system of Staphylococcus aureus but with different outcomes. IMPORTANCE Streptococci are an important species that prefer to grow under anaerobic or microaerophilic environments. Studies have shown that streptococci growth in an aerobic environment generates oxidative stress responses by activating various defense systems, including production of antimicrobial peptides called bacteriocins. This study highlights the importance of a two-component response regulator (ComE) that senses the aerobic environment and induces bacteriocin production in Streptococcus mutans, a dental pathogen. We believe increased bacteriocin secretion under aerobic conditions is necessary for survival and colonization of S. mutans in the oral cavity by inhibiting other competing organisms. Redox sensing by response regulator might be a widespread phenomenon since two other ComE homologs from pathogenic streptococci that inhabit diverse environmental niches also perform a similar function.
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27
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Iobbi V, Brun P, Bernabé G, Dougué Kentsop RA, Donadio G, Ruffoni B, Fossa P, Bisio A, De Tommasi N. Labdane Diterpenoids from Salvia tingitana Etl. Synergize with Clindamycin against Methicillin-Resistant Staphylococcus aureus. Molecules 2021; 26:6681. [PMID: 34771089 PMCID: PMC8587691 DOI: 10.3390/molecules26216681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 01/21/2023] Open
Abstract
Quorum-sensing (QS) is a regulatory mechanism in bacterial communication, important for pathogenesis control. The search for small molecules active as quorum-sensing inhibitors (QSI) that can synergize with antibiotics is considered a good strategy to counteract the problem of antibiotic resistance. Here the antimicrobial labdane diterpenoids sclareol (1) and manool (2) extracted from Salvia tingitana were considered as potential QSI against methicillin-resistant Staphylococcus aureus. Only sclareol showed synergistic activity with clindamycin. The quantification of these compounds by LC-MS analysis in the organs and in the calli of S. tingitana showed that sclareol is most abundant in the flower spikes and is produced by calli, while manool is the major labdane of the roots, and is abundant also in the leaves. Other metabolites of the roots were abietane diterpenoids, common in Salvia species, and pentacyclic triterpenoids, bearing a γ-lactone moiety, previously undescribed in Salvia. Docking simulations suggested that 1 and 2 bind to key residues, involved in direct interactions with DNA. They may prevent accessory gene regulator A (AgrA) binding to DNA or AgrA activation upon phosphorylation, to suppress virulence factor expression. The antimicrobial activity of these two compounds probably achieves preventing upregulation of the accessory gene regulator (agr)-regulated genes.
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Affiliation(s)
- Valeria Iobbi
- Department of Pharmacy, University of Genova, Viale Cembrano 4, 16148 Genova, Italy; (V.I.); (R.A.D.K.); (P.F.)
| | - Paola Brun
- Department of Molecular Medicine, University of Padova, Via Gabelli 63, 35121 Padova, Italy; (P.B.); (G.B.)
| | - Giulia Bernabé
- Department of Molecular Medicine, University of Padova, Via Gabelli 63, 35121 Padova, Italy; (P.B.); (G.B.)
| | - Roméo Arago Dougué Kentsop
- Department of Pharmacy, University of Genova, Viale Cembrano 4, 16148 Genova, Italy; (V.I.); (R.A.D.K.); (P.F.)
- Consiglio per la Ricerca e la Sperimentazione in Agricoltura–CREA Centro di ricerca Orticoltura e Florovivaismo, 18038 San Remo, Italy;
| | - Giuliana Donadio
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Salerno, Italy; (G.D.); (N.D.T.)
| | - Barbara Ruffoni
- Consiglio per la Ricerca e la Sperimentazione in Agricoltura–CREA Centro di ricerca Orticoltura e Florovivaismo, 18038 San Remo, Italy;
| | - Paola Fossa
- Department of Pharmacy, University of Genova, Viale Cembrano 4, 16148 Genova, Italy; (V.I.); (R.A.D.K.); (P.F.)
| | - Angela Bisio
- Department of Pharmacy, University of Genova, Viale Cembrano 4, 16148 Genova, Italy; (V.I.); (R.A.D.K.); (P.F.)
| | - Nunziatina De Tommasi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II 132, 84084 Salerno, Italy; (G.D.); (N.D.T.)
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Structural and functional characterization of the bacterial biofilm activator RemA. Nat Commun 2021; 12:5707. [PMID: 34588455 PMCID: PMC8481266 DOI: 10.1038/s41467-021-26005-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 09/07/2021] [Indexed: 11/23/2022] Open
Abstract
Bacillus subtilis can form structurally complex biofilms on solid or liquid surfaces, which requires expression of genes for matrix production. The transcription of these genes is activated by regulatory protein RemA, which binds to poorly conserved, repetitive DNA regions but lacks obvious DNA-binding motifs or domains. Here, we present the structure of the RemA homologue from Geobacillus thermodenitrificans, showing a unique octameric ring with the potential to form a 16-meric superstructure. These results, together with further biochemical and in vivo characterization of B. subtilis RemA, suggests that the protein can wrap DNA around its ring-like structure through a LytTR-related domain. Biofilm formation in Bacillus subtilis requires expression of matrix production genes, which are upregulated by transcriptional activator RemA. Here, the authors show that RemA forms octameric rings with the potential to form a 16-meric superstructure, suggesting that the protein can wrap DNA through a LytTR-related domain.
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Singh S, Bhatia S. Quorum Sensing Inhibitors: Curbing Pathogenic Infections through Inhibition of Bacterial Communication. IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2021; 20:486-514. [PMID: 34567177 PMCID: PMC8457738 DOI: 10.22037/ijpr.2020.113470.14318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Currently, most of the developed and developing countries are facing the problem of infectious diseases. The genius way of an exaggerated application of antibiotics led the infectious agents to respond by bringing a regime of persisters to resist antibiotics attacks prolonging their survival. Persisters have the dexterity to communicate among themself using signal molecules via the process of Quorum Sensing (QS), which regulates virulence gene expression and biofilms formation, making them more vulnerable to antibiotic attack. Our review aims at the different approaches applied in the ordeal to solve the riddle for QS inhibitors. QS inhibitors, their origin, structures and key interactions for QS inhibitory activity have been summarized. Solicitation of a potent QS inhibitor molecule would be beneficial, giving new life to the simplest antibiotics in adjuvant therapy.
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Affiliation(s)
- Shaminder Singh
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3 Milestone, Faridabad-Gurugram Expressway, Faridabad - 121 001, Haryana, India
| | - Sonam Bhatia
- Department of Pharmaceutical Science, SHALOM Institute of Health and Allied Sciences, Sam Higginbottom University of Agriculture, Technology and Sciences (SHUATS), Naini-211007, Prayagraj, Uttar Pradesh, India
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30
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Silva MA, Salgueiro CA. Multistep Signaling in Nature: A Close-Up of Geobacter Chemotaxis Sensing. Int J Mol Sci 2021; 22:ijms22169034. [PMID: 34445739 PMCID: PMC8396549 DOI: 10.3390/ijms22169034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/30/2021] [Accepted: 08/09/2021] [Indexed: 11/23/2022] Open
Abstract
Environmental changes trigger the continuous adaptation of bacteria to ensure their survival. This is possible through a variety of signal transduction pathways involving chemoreceptors known as methyl-accepting chemotaxis proteins (MCP) that allow the microorganisms to redirect their mobility towards favorable environments. MCP are two-component regulatory (or signal transduction) systems (TCS) formed by a sensor and a response regulator domain. These domains synchronize transient protein phosphorylation and dephosphorylation events to convert the stimuli into an appropriate cellular response. In this review, the variability of TCS domains and the most common signaling mechanisms are highlighted. This is followed by the description of the overall cellular topology, classification and mechanisms of MCP. Finally, the structural and functional properties of a new family of MCP found in Geobacter sulfurreducens are revisited. This bacterium has a diverse repertoire of chemosensory systems, which represents a striking example of a survival mechanism in challenging environments. Two G. sulfurreducens MCP—GSU0582 and GSU0935—are members of a new family of chemotaxis sensor proteins containing a periplasmic PAS-like sensor domain with a c-type heme. Interestingly, the cellular location of this domain opens new routes to the understanding of the redox potential sensing signaling transduction pathways.
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Affiliation(s)
- Marta A. Silva
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal;
- UCIBIO—Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Carlos A. Salgueiro
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal;
- UCIBIO—Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
- Correspondence:
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Interference in Staphylococcus Aureus Biofilm and Virulence Factors Production by Human Probiotic Bacteria with Antimutagenic Activity. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2021. [DOI: 10.1007/s13369-021-05934-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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32
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Baković J, Yu BYK, Silva D, Baczynska M, Peak-Chew SY, Switzer A, Burchell L, Wigneshweraraj S, Vandanashree M, Gopal B, Filonenko V, Skehel M, Gout I. Redox Regulation of the Quorum-sensing Transcription Factor AgrA by Coenzyme A. Antioxidants (Basel) 2021; 10:antiox10060841. [PMID: 34070323 PMCID: PMC8228455 DOI: 10.3390/antiox10060841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/21/2021] [Accepted: 05/21/2021] [Indexed: 12/23/2022] Open
Abstract
Staphylococcus aureus (S. aureus) is an aggressive opportunistic pathogen of prominent virulence and antibiotic resistance. These characteristics are due in part to the accessory gene regulator (agr) quorum-sensing system, which allows for the rapid adaptation of S. aureus to environmental changes and thus promotes virulence and the development of pathogenesis. AgrA is the agr system response regulator that binds to the P2 and P3 promoters and upregulates agr expression. In this study, we reveal that S. aureus AgrA is modified by covalent binding of CoA (CoAlation) in response to oxidative or metabolic stress. The sites of CoAlation were mapped by liquid chromatography tandem mass spectrometry (LC-MS/MS) and revealed that oxidation-sensing Cys199 is modified by CoA. Surface plasmon resonance (SPR) analysis showed an inhibitory effect of CoAlation on the DNA-binding activity, as CoAlated AgrA had significantly lower affinity towards the P2 and P3 promoters than non-CoAlated AgrA. Overall, this study provides novel insights into the mode of transcriptional regulation in S. aureus and further elucidates the link between the quorum-sensing and oxidation-sensing roles of the agr system.
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Affiliation(s)
- Jovana Baković
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
| | - Bess Yi Kun Yu
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
| | - Daniel Silva
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
| | - Maria Baczynska
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
| | - Sew Yeu Peak-Chew
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK; (S.Y.P.-C.); (M.S.)
| | - Amy Switzer
- Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; (A.S.); (L.B.); (S.W.)
| | - Lynn Burchell
- Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; (A.S.); (L.B.); (S.W.)
| | - Sivaramesh Wigneshweraraj
- Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; (A.S.); (L.B.); (S.W.)
| | | | - Balasubramanian Gopal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India; (M.V.); (B.G.)
| | - Valeriy Filonenko
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, 143 Kyiv, Ukraine;
| | - Mark Skehel
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK; (S.Y.P.-C.); (M.S.)
| | - Ivan Gout
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, 143 Kyiv, Ukraine;
- Correspondence: ; Tel.: +0044-2076794482; Fax: +0044-2076797193
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Bernabè G, Dal Pra M, Ronca V, Pauletto A, Marzaro G, Saluzzo F, Stefani A, Artusi I, De Filippis V, Ferlin MG, Brun P, Castagliuolo I. A Novel Aza-Derivative Inhibits agr Quorum Sensing Signaling and Synergizes Methicillin-Resistant Staphylococcus aureus to Clindamycin. Front Microbiol 2021; 12:610859. [PMID: 33633702 PMCID: PMC7899991 DOI: 10.3389/fmicb.2021.610859] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 01/15/2021] [Indexed: 01/21/2023] Open
Abstract
Increasing antibiotic resistance and diminishing pharmaceutical industry investments have increased the need for molecules that can treat infections caused by dangerous pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). Quorum Sensing (QS) is a signaling mechanism that regulates bacterial virulence in pathogens. A report demonstrating that the anti-inflammatory drug Diflunisal reduces MRSA virulence factors' expression prompted us to design, synthesize and test 16 aza-analogs as inhibitors of S. aureus virulence factors controlled by the accessory gene regulator (agr) QS system. At first, we evaluated by qRT-PCR the activity of compounds on rnaIII expression, a QS related gene. Azan-7 was the most active molecule tested and it did not show cytotoxic activity in human cell lines. Moreover, we demonstrated that it did not affect bacterial proliferation. Regulation of MRSA virulence genes by Azan-7 was investigated using qRT-PCR and RNAseq. Azan-7 significantly reduced hla, psmα, hysA, agrA, cap1A, and cap1C gene expression. In silico docking demonstrated that Azan-7 binds the response regulator AgrA. This data was confirmed by electrophoretic mobility shift assay (EMSA) reporting that Azan-7 binding to AgrA protein strongly reduced the AgrA-DNA complex formation at the P3 promoter region involved in the regulation of rnaIII transcription. Azan-7 inhibited MRSA-mediated haemolysis, reduced survival of the pathogen at low pH levels, and increased macrophage killing. In addition, Azan-7 enhanced MRSA susceptibility to clindamycin both in planktonic growth and biofilm. Azan-7 did not induce resistance over 10 days in culture. It was equally active against all the AgrA MRSA subtypes encountered among clinical isolates, but it was not active against Staphylococcus epidermidis, although the AgrA proteins show an approximate 80% homology. These results demonstrate that Azan-7 inhibits the expression of MRSA virulence factors by interfering in the QS and synergizes MRSA biofilm with clindamycin, indicating the compound as a promising candidate for the treatment of MRSA infections.
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Affiliation(s)
- Giulia Bernabè
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Matteo Dal Pra
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Vittoria Ronca
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Anthony Pauletto
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Giovanni Marzaro
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | | | - Annalisa Stefani
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Ilaria Artusi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Vincenzo De Filippis
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Maria Grazia Ferlin
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Paola Brun
- Department of Molecular Medicine, University of Padua, Padua, Italy
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Patel DT, O'Bier NS, Schuler EJA, Marconi RT. The Treponema denticola DgcA protein (TDE0125) is a functional diguanylate cyclase. Pathog Dis 2021; 79:6102550. [PMID: 33452878 DOI: 10.1093/femspd/ftab004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/13/2021] [Indexed: 11/12/2022] Open
Abstract
Periodontal disease (PD) is a progressive inflammatory condition characterized by degradation of the gingival epithelium, periodontal ligament, and alveolar bone ultimately resulting in tooth loss. Treponema denticola is a keystone periopathogen that contributes to immune dysregulation and direct tissue destruction. As periodontal disease develops, T. denticola must adapt to environmental, immunological and physiochemical changes in the subgingival crevice. Treponema denticola produces bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), an important regulatory nucleotide. While T. denticola encodes several putative diguanylate cyclases (DGCs), none have been studied and hence the biological role of c-di-GMP in oral treponemes remains largely unexplored. Here, we demonstrate that the T. denticola open reading frame, TDE0125, encodes a functional DGC designated as DgcA (Diguanylate cyclase A). The dgcA gene is universal among T. denticola isolates, highly conserved and is a stand-alone GGEEF protein with a GAF domain. Recombinant DgcA converts GTP to c-di-GMP using either manganese or magnesium under aerobic and anaerobic reaction conditions. Size exclusion chromatography revealed that DgcA exists as a homodimer and in larger oligomers. Site-directed mutagenesis of residues that define the putative inhibitory site of DgcA suggest that c-di-GMP production is allosterically regulated. This report is the first to characterize a DGC of an oral treponeme.
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Affiliation(s)
- Dhara T Patel
- Department of Microbiology and Immunology, VCU Medical Center, 1112 East Clay Street, Room 101 McGuire Hall, PO Box 980678, Richmond, VA 23298-0678, USA
| | - Nathaniel S O'Bier
- Department of Microbiology and Immunology, VCU Medical Center, 1112 East Clay Street, Room 101 McGuire Hall, PO Box 980678, Richmond, VA 23298-0678, USA
| | - Edward J A Schuler
- Department of Microbiology and Immunology, VCU Medical Center, 1112 East Clay Street, Room 101 McGuire Hall, PO Box 980678, Richmond, VA 23298-0678, USA
| | - Richard T Marconi
- Department of Microbiology and Immunology, VCU Medical Center, 1112 East Clay Street, Room 101 McGuire Hall, PO Box 980678, Richmond, VA 23298-0678, USA
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2-(2-Methyl-2-nitrovinyl)furan but Not Furvina Interfere with Staphylococcus aureus Agr Quorum-Sensing System and Potentiate the Action of Fusidic Acid against Biofilms. Int J Mol Sci 2021; 22:ijms22020613. [PMID: 33435417 PMCID: PMC7827229 DOI: 10.3390/ijms22020613] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/31/2020] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
Quorum sensing (QS) plays an essential role in the production of virulence factors, in biofilm formation and antimicrobial resistance. Consequently, inhibiting QS is being considered a promising target for antipathogenic/anti-virulence therapies. This study aims to screen 2-nitrovinylfuran derivatives structurally related to Furvina (a broad-spectrum antibiotic already used for therapeutic purposes) for their effects on QS and in biofilm prevention/control. Furvina and four 2-nitrovinylfuran derivatives (compounds 1–4) were tested to assess the ability to interfere with QS of Staphylococcus aureus using bioreporter strains (S. aureus ALC1742 and ALC1743). The activity of Furvina and the most promising quorum-sensing inhibitor (QSI) was evaluated in biofilm prevention and in biofilm control (combined with fusidic acid). The biofilms were further characterized in terms of biofilm mass, viability and membrane integrity. Compound 2 caused the most significant QS inhibition with reductions between 60% and 80%. Molecular docking simulations indicate that this compound interacts preferentially with the protein hydrophobic cleft in the LytTR domain of AgrA pocket. Metabolic inactivations of 40% for S. aureus ALC1742 and 20% for S. aureus ALC1743 were reached. A 24 h-old biofilm formed in the presence of the QSI increased the metabolic inactivation by fusidic acid to 80%, for both strains. The overall results highlight the effects of compound 2 as well as the potential of combining QSI with in-use antibiotics for the management of skin and soft tissues infections.
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Ibrahim YM, Abouwarda AM, Nasr T, Omar FA, Bondock S. Antibacterial and anti-quorum sensing activities of a substituted thiazole derivative against methicillin-resistant Staphylococcus aureus and other multidrug-resistant bacteria. Microb Pathog 2020; 149:104500. [DOI: 10.1016/j.micpath.2020.104500] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/16/2020] [Accepted: 09/07/2020] [Indexed: 10/23/2022]
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Silence as a way of niche adaptation: mecC-MRSA with variations in the accessory gene regulator (agr) functionality express kaleidoscopic phenotypes. Sci Rep 2020; 10:14787. [PMID: 32901059 PMCID: PMC7479134 DOI: 10.1038/s41598-020-71640-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 08/19/2020] [Indexed: 11/09/2022] Open
Abstract
Functionality of the accessory gene regulator (agr) quorum sensing system is an important factor promoting either acute or chronic infections by the notorious opportunistic human and veterinary pathogen Staphylococcus aureus. Spontaneous alterations of the agr system are known to frequently occur in human healthcare-associated S. aureus lineages. However, data on agr integrity and function are sparse regarding other major clonal lineages. Here we report on the agr system functionality and activity level in mecC-carrying methicillin resistant S. aureus (MRSA) of various animal origins (n = 33) obtained in Europe as well as in closely related human isolates (n = 12). Whole genome analysis assigned all isolates to four clonal complexes (CC) with distinct agr types (CC599 agr I, CC49 agr II, CC130 agr III and CC1943 agr IV). Agr functionality was assessed by a combination of phenotypic assays and proteome analysis. In each CC, isolates with varying agr activity levels were detected, including the presence of completely non-functional variants. Genomic comparison of the agr I-IV encoding regions associated these phenotypic differences with variations in the agrA and agrC genes. The genomic changes were detected independently in divergent lineages, suggesting that agr variation might foster viability and adaptation of emerging MRSA lineages to distinct ecological niches.
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Abstract
Identifying new binding forces between electron donor and acceptor entities is key to properly understanding molecular recognition and aggregation phenomena, which are of inmense importance to biology. For decades, the halogenation of DNA/RNA bases has been routinely carried out to solve solid state structures of nucleic acids (NA). However, the effects of this modification might be deeper than just a simple atom substitution since halogens are also known to undergo noncovalent binding (halogen bonding). Herein we show that halogenated NAs with either Br or I atoms are able to establish halogen bonds with properly disposed protein residues. An inspection of the Protein Data Bank (PDB) reveals several examples involving 5-iodo/5-bromouracil, 8-bromoadenine, and 5-iodocytosine bases that are consistent with the halogen bond geometry features. Computations reveal the favorable and moderately strong nature of this interaction, thus confirming the ability of halogenated bases to actively participate in protein-NA binding.
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Affiliation(s)
- Antonio Frontera
- Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122 Palma, Baleares, Spain
| | - Antonio Bauzá
- Department of Chemistry, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122 Palma, Baleares, Spain
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Marchetti M, De Bei O, Bettati S, Campanini B, Kovachka S, Gianquinto E, Spyrakis F, Ronda L. Iron Metabolism at the Interface between Host and Pathogen: From Nutritional Immunity to Antibacterial Development. Int J Mol Sci 2020; 21:E2145. [PMID: 32245010 PMCID: PMC7139808 DOI: 10.3390/ijms21062145] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 02/08/2023] Open
Abstract
Nutritional immunity is a form of innate immunity widespread in both vertebrates and invertebrates. The term refers to a rich repertoire of mechanisms set up by the host to inhibit bacterial proliferation by sequestering trace minerals (mainly iron, but also zinc and manganese). This strategy, selected by evolution, represents an effective front-line defense against pathogens and has thus inspired the exploitation of iron restriction in the development of innovative antimicrobials or enhancers of antimicrobial therapy. This review focuses on the mechanisms of nutritional immunity, the strategies adopted by opportunistic human pathogen Staphylococcus aureus to circumvent it, and the impact of deletion mutants on the fitness, infectivity, and persistence inside the host. This information finally converges in an overview of the current development of inhibitors targeting the different stages of iron uptake, an as-yet unexploited target in the field of antistaphylococcal drug discovery.
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Affiliation(s)
- Marialaura Marchetti
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
| | - Omar De Bei
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (O.D.B.); (B.C.)
| | - Stefano Bettati
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
- Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
- Institute of Biophysics, National Research Council, 56124 Pisa, Italy
- National Institute of Biostructures and Biosystems, 00136 Rome, Italy
| | - Barbara Campanini
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (O.D.B.); (B.C.)
| | - Sandra Kovachka
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Eleonora Gianquinto
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Francesca Spyrakis
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Luca Ronda
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
- Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
- Institute of Biophysics, National Research Council, 56124 Pisa, Italy
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40
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Horswill AR, Gordon CP. Structure-Activity Relationship Studies of Small Molecule Modulators of the Staphylococcal Accessory Gene Regulator. J Med Chem 2019; 63:2705-2730. [PMID: 31658413 DOI: 10.1021/acs.jmedchem.9b00798] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The accessory gene regulator (agr) quorum-sensing system is arguably the most important regulator of Staphylococcus virulence. The agr-system serves a crucial role in pathogenesis by triggering substantive gene expression alterations to up-regulate the production of a wide variety of virulence determinants such as exoenzymes (proteases, lipases, nucleases) and downregulate the expression of surface binding proteins. Accordingly, the agr-system represents a compelling target for the development of antivirulence therapeutics as potential adjuncts, or alternatives, to conventional bactericidal and bacteriostatic antibiotics. Despite this potential, to date, no agr-system inhibitors have progressed to the clinic; however, several promising lead compounds have been identified through screens of synthetic and natural product libraries. On the basis of the molecular components within the agr-system, the current contingent of regulating compounds can be clustered into three broad groups, AgrA-P3 activation inhibitors, AgrB-AgrD processing inhibitors, and AgrC-AIP interaction inhibitors. This review aims to provide an overview of the development, structure-activity-relationships, and limitations of compounds within each of these groups in addition to the current opportunities for developing next-generation anologs.
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Affiliation(s)
- Alexander R Horswill
- Veterans Affairs Eastern Colorado Health Care System, Aurora, Colorado 80045, United States.,Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - Christopher P Gordon
- School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith South DC, NSW 2751, Australia.,Molecular Medicine Research Group, School of Medicine, Westerm Sydney University, Building 30, Campbelltown, NSW 2560, Australia
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Abstract
Response regulators function as the output components of two-component systems, which couple the sensing of environmental stimuli to adaptive responses. Response regulators typically contain conserved receiver (REC) domains that function as phosphorylation-regulated switches to control the activities of effector domains that elicit output responses. This modular design is extremely versatile, enabling different regulatory strategies tuned to the needs of individual signaling systems. This review summarizes structural features that underlie response regulator function. An abundance of atomic resolution structures and complementary biochemical data have defined the mechanisms for response regulator enzymatic activities, revealed trends in regulatory strategies utilized by response regulators of different subfamilies, and provided insights into interactions of response regulators with their cognate histidine kinases. Among the hundreds of thousands of response regulators identified, variations abound. This article provides a framework for understanding structural features that enable function of canonical response regulators and a basis for distinguishing noncanonical configurations.
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Affiliation(s)
- Rong Gao
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA; , ,
| | - Sophie Bouillet
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA; , ,
| | - Ann M Stock
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA; , ,
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42
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Bezar IF, Mashruwala AA, Boyd JM, Stock AM. Drug-like Fragments Inhibit agr-Mediated Virulence Expression in Staphylococcus aureus. Sci Rep 2019; 9:6786. [PMID: 31043623 PMCID: PMC6494831 DOI: 10.1038/s41598-019-42853-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 04/01/2019] [Indexed: 11/23/2022] Open
Abstract
In response to the increasingly problematic emergence of antibiotic resistance, novel strategies for combating pathogenic bacteria are being investigated. Targeting the agr quorum sensing system, which regulates expression of virulence in Staphylococcus aureus, is one potentially useful approach for combating drug-resistant pathogens that has not yet been fully explored. A previously published study of a fragment screen resulted in the identification of five compound fragments that interact with the DNA-binding domain of the response regulator AgrA from S. aureus. We have analyzed the ability of these compounds to affect agr-mediated virulence gene expression in cultured S. aureus cells. Three of the compounds demonstrated the ability to reduce agr-driven transcription at the P2 and P3 promoters of the agr operon and increase biofilm formation, and two of these compounds also showed the ability to reduce levels of secreted toxins. The finding that the compounds tested were able to reduce agr activity suggests that they could be useful tools for probing the effects of agr inhibition. Furthermore, the characteristics of compound fragments make them good starting materials for the development of compound libraries to iteratively improve the inhibitors.
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Affiliation(s)
- Ian F Bezar
- Department of Biochemistry and Molecular Biology, Center for Advanced Biotechnology and Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, 08854, USA
- Graduate School of Biomedical Sciences at Robert Wood Johnson Medical School, Piscataway, New Jersey, 08854, USA
| | - Ameya A Mashruwala
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey, 08901, USA
- Graduate School-New Brunswick, Rutgers University, New Brunswick, New Jersey, 08901, USA
- Department of Molecular Biology, Princeton University, Princeton, 08544, New Jersey, USA
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey, 08901, USA
| | - Ann M Stock
- Department of Biochemistry and Molecular Biology, Center for Advanced Biotechnology and Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, 08854, USA.
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43
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Jung K, Fabiani F, Hoyer E, Lassak J. Bacterial transmembrane signalling systems and their engineering for biosensing. Open Biol 2019; 8:rsob.180023. [PMID: 29695618 PMCID: PMC5936718 DOI: 10.1098/rsob.180023] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/03/2018] [Indexed: 12/27/2022] Open
Abstract
Every living cell possesses numerous transmembrane signalling systems that receive chemical and physical stimuli from the environment and transduce this information into an intracellular signal that triggers some form of cellular response. As unicellular organisms, bacteria require these systems for survival in rapidly changing environments. The receptors themselves act as ‘sensory organs’, while subsequent signalling circuits can be regarded as forming a ‘neural network’ that is involved in decision making, adaptation and ultimately in ensuring survival. Bacteria serve as useful biosensors in industry and clinical diagnostics, in addition to producing drugs for therapeutic purposes. Therefore, there is a great demand for engineered bacterial strains that contain transmembrane signalling systems with high molecular specificity, sensitivity and dose dependency. In this review, we address the complexity of transmembrane signalling systems and discuss principles to rewire receptors and their signalling outputs.
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Affiliation(s)
- Kirsten Jung
- Munich Center for Integrated Protein Science (CiPSM) at the Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Florian Fabiani
- Munich Center for Integrated Protein Science (CiPSM) at the Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Elisabeth Hoyer
- Munich Center for Integrated Protein Science (CiPSM) at the Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Jürgen Lassak
- Munich Center for Integrated Protein Science (CiPSM) at the Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
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44
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Xie Q, Zhao A, Jeffrey PD, Kim MK, Bassler BL, Stone HA, Novick RP, Muir TW. Identification of a Molecular Latch that Regulates Staphylococcal Virulence. Cell Chem Biol 2019; 26:548-558.e4. [PMID: 30773482 DOI: 10.1016/j.chembiol.2019.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 11/27/2018] [Accepted: 01/10/2019] [Indexed: 01/04/2023]
Abstract
Virulence induction in the Staphylococcus aureus is under the control of a quorum sensing (QS) circuit encoded by the accessory gene regulator (agr) locus. Allelic variation within agr produces four QS specificity groups, each producing a unique secreted autoinducer peptide (AIP) and receptor histidine kinase (RHK), AgrC. Cognate AIP-AgrC interactions activate virulence through a two-component signaling cascade, whereas non-cognate pairs are generally inhibitory. Here we pinpoint a key hydrogen-bonding interaction within AgrC that acts as a switch to convert helical motions propagating from the receptor sensor domain into changes in inter-domain association within the kinase module. AgrC mutants lacking this interaction are constitutively active in vitro and in vivo, the latter leading to a pronounced attenuation of S. aureus biofilm formation. Thus, our work sheds light on the regulation of this biomedically important RHK.
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Affiliation(s)
- Qian Xie
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Washington Road, Princeton, NJ 08544-0015, USA
| | - Aishan Zhao
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Washington Road, Princeton, NJ 08544-0015, USA
| | - Philip D Jeffrey
- Department of Molecular Biology, Princeton University, Schultz Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Minyoung Kevin Kim
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Washington Road, Princeton, NJ 08544-0015, USA
| | - Bonnie L Bassler
- Department of Molecular Biology, Princeton University, Schultz Laboratory, Washington Road, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Engineering Quadrangle, Olden Street, Princeton, NJ 08544, USA
| | - Richard P Novick
- Skirball Institute, Department of Microbiology, NYU Medical Center, 540-562 First Avenue, New York, NY 10016, USA
| | - Tom W Muir
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Washington Road, Princeton, NJ 08544-0015, USA.
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45
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Greenberg M, Kuo D, Jankowsky E, Long L, Hager C, Bandi K, Ma D, Manoharan D, Shoham Y, Harte W, Ghannoum MA, Shoham M. Small-molecule AgrA inhibitors F12 and F19 act as antivirulence agents against Gram-positive pathogens. Sci Rep 2018; 8:14578. [PMID: 30275455 PMCID: PMC6167350 DOI: 10.1038/s41598-018-32829-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 09/17/2018] [Indexed: 01/20/2023] Open
Abstract
Small-molecule antivirulence agents represent a promising alternative or adjuvant to antibiotics. These compounds disarm pathogens of disease-causing toxins without killing them, thereby diminishing survival pressure to develop resistance. Here we show that the small-molecule antivirulence agents F12 and F19 block staphylococcal transcription factor AgrA from binding to its promoter. Consequently, toxin expression is inhibited, thus preventing host cell damage by Gram-positive pathogens. Broad spectrum efficacy against Gram-positive pathogens is due to the existence of AgrA homologs in many Gram-positive bacteria. F12 is more efficacious in vitro and F19 works better in vivo. In a murine MRSA bacteremia/sepsis model, F19 treatment alone resulted in 100% survival while untreated animals had 70% mortality. Furthermore, F19 enhances antibiotic efficacy in vivo. Notably, in a murine MRSA wound infection model, combination of F19 with antibiotics resulted in bacterial load reduction. Thus, F19 could be used alone or in combination with antibiotics to prevent and treat infections of Gram-positive pathogens.
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Affiliation(s)
- Michael Greenberg
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - David Kuo
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Eckhard Jankowsky
- Center for RNA and Therapeutics, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Lisa Long
- Department of Dermatology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Chris Hager
- Department of Dermatology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Kiran Bandi
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,University of Pittsburgh School of Medicine, Pittsburgh, USA
| | - Danyang Ma
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Divya Manoharan
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | | | - William Harte
- Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Mahmoud A Ghannoum
- Department of Dermatology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Menachem Shoham
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA. .,Q2 Pharma, Ltd., Haifa, Israel.
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Host Nitric Oxide Disrupts Microbial Cell-to-Cell Communication to Inhibit Staphylococcal Virulence. Cell Host Microbe 2018; 23:594-606.e7. [PMID: 29706505 DOI: 10.1016/j.chom.2018.04.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 03/07/2018] [Accepted: 04/05/2018] [Indexed: 12/11/2022]
Abstract
Staphylococcus aureus is a commensal bacterium that can asymptomatically colonize its host but also causes invasive infections. Quorum sensing regulates S. aureus virulence and the transition from a commensal to a pathogenic organism. However, little is known about how host innate immunity affects interbacterial communication. We show that nitric oxide suppresses staphylococcal virulence by targeting the Agr quorum sensing system. Nitric oxide-mediated inhibition occurs through direct modification of cysteine residues C55, C123, and C199 of the AgrA transcription factor. Cysteine modification decreases AgrA promoter occupancy as well as transcription of the agr operon and quorum sensing-activated toxin genes. In a staphylococcal pneumonia model, mice lacking inducible nitric oxide synthase develop more severe disease with heightened mortality and proinflammatory cytokine responses. In addition, staphylococcal α-toxin production increases in the absence of nitric oxide or nitric oxide-sensitive AgrA cysteine residues. Our findings demonstrate an anti-virulence mechanism for nitric oxide in innate immunity.
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Piñas GE, Reinoso-Vizcaino NM, Yandar Barahona NY, Cortes PR, Duran R, Badapanda C, Rathore A, Bichara DR, Cian MB, Olivero NB, Perez DR, Echenique J. Crosstalk between the serine/threonine kinase StkP and the response regulator ComE controls the stress response and intracellular survival of Streptococcus pneumoniae. PLoS Pathog 2018; 14:e1007118. [PMID: 29883472 PMCID: PMC6010298 DOI: 10.1371/journal.ppat.1007118] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 06/20/2018] [Accepted: 05/23/2018] [Indexed: 11/30/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic human bacterial pathogen that usually colonizes the upper respiratory tract, but the invasion and survival mechanism in respiratory epithelial cells remains elusive. Previously, we described that acidic stress-induced lysis (ASIL) and intracellular survival are controlled by ComE through a yet unknown activation mechanism under acidic conditions, which is independent of the ComD histidine kinase that activates this response regulator for competence development at pH 7.8. Here, we demonstrate that the serine/threonine kinase StkP is essential for ASIL, and show that StkP phosphorylates ComE at Thr128. Molecular dynamic simulations predicted that Thr128-phosphorylation induces conformational changes on ComE’s DNA-binding domain. Using nonphosphorylatable (ComET128A) and phosphomimetic (ComET128E) proteins, we confirmed that Thr128-phosphorylation increased the DNA-binding affinity of ComE. The non-phosphorylated form of ComE interacted more strongly with StkP than the phosphomimetic form at acidic pH, suggesting that pH facilitated crosstalk. To identify the ComE-regulated genes under acidic conditions, a comparative transcriptomic analysis was performed between the comET128A and wt strains, and differential expression of 104 genes involved in different cellular processes was detected, suggesting that the StkP/ComE pathway induced global changes in response to acidic stress. In the comET128A mutant, the repression of spxB and sodA correlated with decreased H2O2 production, whereas the reduced expression of murN correlated with an increased resistance to cell wall antibiotic-induced lysis, compatible with cell wall alterations. In the comET128A mutant, ASIL was blocked and acid tolerance response was higher compared to the wt strain. These phenotypes, accompanied with low H2O2 production, are likely responsible for the increased survival in pneumocytes of the comET128A mutant. We propose that the StkP/ComE pathway controls the stress response, thus affecting the intracellular survival of S. pneumoniae in pneumocytes, one of the first barriers that this pathogen must cross to establish an infection. Streptococcus pneumoniae is a major human pathogen and is the causal agent of otitis (media) and sinusitis. It is also responsible for severe infections such as bacteremia, pneumonia, and meningitis, associated with 2 million annual deaths. Although this bacterium is part of the human nasopharynx commensal microbiota, it can become a pathogen and cross the epithelial cell barrier to establishing infections of varying intensity. Although S. pneumoniae is considered to be a typical extracellular pathogen, transient intracellular life forms have been found in eukaryotic cells, suggesting a putative survival mechanism. Here, we report that the serine-threonine kinase StkP was able to phosphorylate the response regulator ComE to control different cellular processes in response to environmental stress. Moreover, the phosphorylation of ComE on Thr128, and the consequent conformational and functional changes resulting from this event, extended the current knowledge of molecular activation mechanisms of response regulators. In this report, we provide evidence for the regulatory control exerted by the StkP/ComE pathway on acid-induced autolysis (associated with pneumolysin release), the acid tolerance response, and H2O2 production to modulate tissue damage and intracellular survival, which are ultimately linked to pneumococcal pathogenesis.
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Affiliation(s)
- Germán E. Piñas
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
| | - Nicolás M. Reinoso-Vizcaino
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nubia Y. Yandar Barahona
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Paulo R. Cortes
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Rosario Duran
- Instituto Pasteur de Montevideo and Instituto de Investigaciones Biológicas Clemente Estable, Unidad de Bioquímica y Proteómica Analíticas, Montevideo, Uruguay
| | | | - Ankita Rathore
- Bioinformatics Division, Xcelris Lab Limited, Ahmedabad, India
| | | | - Melina B. Cian
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nadia B. Olivero
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Daniel R. Perez
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - José Echenique
- Departamento de Bioquímica Clínica—CIBICI (CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- * E-mail:
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The MerR-like protein BldC binds DNA direct repeats as cooperative multimers to regulate Streptomyces development. Nat Commun 2018; 9:1139. [PMID: 29556010 PMCID: PMC5859096 DOI: 10.1038/s41467-018-03576-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 02/22/2018] [Indexed: 01/18/2023] Open
Abstract
Streptomycetes are notable for their complex life cycle and production of most clinically important antibiotics. A key factor that controls entry into development and the onset of antibiotic production is the 68-residue protein, BldC. BldC is a putative DNA-binding protein related to MerR regulators, but lacks coiled-coil dimerization and effector-binding domains characteristic of classical MerR proteins. Hence, the molecular function of the protein has been unclear. Here we show that BldC is indeed a DNA-binding protein and controls a regulon that includes other key developmental regulators. Intriguingly, BldC DNA-binding sites vary significantly in length. Our BldC-DNA structures explain this DNA-binding capability by revealing that BldC utilizes a DNA-binding mode distinct from MerR and other known regulators, involving asymmetric head-to-tail oligomerization on DNA direct repeats that results in dramatic DNA distortion. Notably, BldC-like proteins radiate throughout eubacteria, establishing BldC as the founding member of a new structural family of regulators. BldC regulates the onset of differentiation in Streptomycetes by a yet unknown molecular mechanism. Using a combination of structural, biochemical and in vivo approaches, the authors show that BldC controls the transcription of several developmental regulators and unravel its DNA binding mode.
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Abstract
Antibiotics have saved millions of lives over the past decades. However, the accumulation of so many antibiotic resistance genes by some clinically relevant pathogens has begun to lead to untreatable infections worldwide. The current antibiotic resistance crisis will require greater efforts by governments and the scientific community to increase the research and development of new antibacterial drugs with new mechanisms of action. A major challenge is the identification of novel microbial targets, essential for in vivo growth or pathogenicity, whose inhibitors can overcome the currently circulating resistome of human pathogens. In this article, we focus on the potential high value of bacterial transcriptional regulators as targets for the development of new antibiotics, discussing in depth the molecular role of these regulatory proteins in bacterial physiology and pathogenesis. Recent advances in the search for novel compounds that inhibit the biological activity of relevant transcriptional regulators in pathogenic bacteria are reviewed.
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A Single-Cell View of the BtsSR/YpdAB Pyruvate Sensing Network in Escherichia coli and Its Biological Relevance. J Bacteriol 2017; 200:JB.00536-17. [PMID: 29038258 DOI: 10.1128/jb.00536-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/09/2017] [Indexed: 12/16/2022] Open
Abstract
Fluctuating environments and individual physiological diversity force bacteria to constantly adapt and optimize the uptake of substrates. We focus here on two very similar two-component systems (TCSs) of Escherichia coli belonging to the LytS/LytTR family: BtsS/BtsR (formerly YehU/YehT) and YpdA/YpdB. Both TCSs respond to extracellular pyruvate, albeit with different affinities, typically during postexponential growth, and each system regulates expression of a single transporter gene, yjiY and yhjX, respectively. To obtain insights into the biological significance of these TCSs, we analyzed the activation of the target promoters at the single-cell level. We found unimodal cell-to-cell variability; however, the degree of variance was strongly influenced by the available nutrients and differed between the two TCSs. We hypothesized that activation of either of the TCSs helps individual cells to replenish carbon resources. To test this hypothesis, we compared wild-type cells with the btsSR ypdAB mutant under two metabolically modulated conditions: protein overproduction and persister formation. Although all wild-type cells were able to overproduce green fluorescent protein (GFP), about half of the btsSR ypdAB population was unable to overexpress GFP. Moreover, the percentage of persister cells, which tolerate antibiotic stress, was significantly lower in the wild-type cells than in the btsSR ypdAB population. Hence, we suggest that the BtsS/BtsR and YpdA/YpdB network contributes to a balancing of the physiological state of all cells within a population.IMPORTANCE Histidine kinase/response regulator (HK/RR) systems enable bacteria to respond to environmental and physiological fluctuations. Escherichia coli and other members of the Enterobacteriaceae possess two similar LytS/LytTR-type HK/RRs, BtsS/BtsR (formerly YehU/YehT) and YpdA/YpdB, which form a functional network. Both systems are activated in response to external pyruvate, typically when cells face overflow metabolism during post-exponential growth. Single-cell analysis of the activation of their respective target genes yjiY and yhjX revealed cell-to-cell variability, and the range of variation was strongly influenced by externally available nutrients. Based on the phenotypic characterization of a btsSR ypdAB mutant compared to the parental strain, we suggest that this TCS network supports an optimization of the physiological state of the individuals within the population.
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