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Giraud E, Baucheron S, Foubert I, Doublet B, Nishino K, Cloeckaert A. Major primary bile salts repress Salmonella enterica serovar Typhimurium invasiveness partly via the efflux regulatory locus ramRA. Front Microbiol 2024; 15:1338261. [PMID: 38410385 PMCID: PMC10895713 DOI: 10.3389/fmicb.2024.1338261] [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: 11/14/2023] [Accepted: 01/29/2024] [Indexed: 02/28/2024] Open
Abstract
Bile represses Salmonella enterica serovar Typhimurium (S. Typhimurium) intestinal cell invasion, but it remains unclear which bile components and mechanisms are implicated. Previous studies reported that bile inhibits the RamR binding to the ramA promoter, resulting in ramA increased transcription, and that ramA overexpression is associated to decreased expression of type III secretion system 1 (TTSS-1) invasion genes and to impaired intestinal cell invasiveness in S. Typhimurium. In this study, we assessed the possible involvement of the ramRA multidrug efflux regulatory locus and individual bile salts in the bile-mediated repression of S. Typhimurium invasion, using Caco-2 intestinal epithelial cells and S. Typhimurium strain ATCC 14028s. Our results indicate that (i) major primary bile salts, chenodeoxycholate and its conjugated-derivative salts, cholate, and deoxycholate, activate ramA transcription in a RamR-dependent manner, and (ii) it results in repression of hilA, encoding the master activator of TTSS-1 genes, and as a consequence in the repression of cellular invasiveness. On the other hand, crude ox bile extract and cholate were also shown to repress the transcription of hilA independently of RamR, and to inhibit cell invasion independently of ramRA. Altogether, these data suggest that bile-mediated repression of S. Typhimurium invasion occurs through pleiotropic effects involving partly ramRA, as well as other unknown regulatory pathways. Bile components other than the bile salts used in this study might also participate in this phenomenon.
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Affiliation(s)
| | | | | | | | - Kunihiko Nishino
- Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
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2
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Joiner JD, Steinchen W, Mozer N, Kronenberger T, Bange G, Poso A, Wagner S, Hartmann MD. HilE represses the activity of the Salmonella virulence regulator HilD via a mechanism distinct from that of intestinal long-chain fatty acids. J Biol Chem 2023; 299:105387. [PMID: 37890783 PMCID: PMC10696396 DOI: 10.1016/j.jbc.2023.105387] [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: 03/19/2023] [Revised: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
The expression of virulence factors essential for the invasion of host cells by Salmonella enterica is tightly controlled by a network of transcription regulators. The AraC/XylS transcription factor HilD is the main integration point of environmental signals into this regulatory network, with many factors affecting HilD activity. Long-chain fatty acids, which are highly abundant throughout the host intestine, directly bind to and repress HilD, acting as environmental cues to coordinate virulence gene expression. The regulatory protein HilE also negatively regulates HilD activity, through a protein-protein interaction. Both of these regulators inhibit HilD dimerization, preventing HilD from binding to target DNA. We investigated the structural basis of these mechanisms of HilD repression. Long-chain fatty acids bind to a conserved pocket in HilD, in a comparable manner to that reported for other AraC/XylS regulators, whereas HilE forms a stable heterodimer with HilD by binding to the HilD dimerization interface. Our results highlight two distinct, mutually exclusive mechanisms by which HilD activity is repressed, which could be exploited for the development of new antivirulence leads.
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Affiliation(s)
- Joe D Joiner
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Wieland Steinchen
- Center for Synthetic Microbiology, Philipps University of Marburg, Marburg, Germany; Department of Chemistry, Philipps University of Marburg, Marburg, Germany
| | - Nick Mozer
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Thales Kronenberger
- Department of Internal Medicine VIII, University Hospital Tübingen, Tübingen, Germany; Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry and Tübingen Center for Academic Drug Discovery & Development (TüCAD2), Eberhard Karls University Tübingen, Tübingen, Germany; School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland; Excellence Cluster "Controlling Microbes to Fight Infections" (CMFI), Tübingen, Germany
| | - Gert Bange
- Center for Synthetic Microbiology, Philipps University of Marburg, Marburg, Germany; Department of Chemistry, Philipps University of Marburg, Marburg, Germany
| | - Antti Poso
- Department of Internal Medicine VIII, University Hospital Tübingen, Tübingen, Germany; Institute of Pharmacy, Pharmaceutical/Medicinal Chemistry and Tübingen Center for Academic Drug Discovery & Development (TüCAD2), Eberhard Karls University Tübingen, Tübingen, Germany; School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Samuel Wagner
- Excellence Cluster "Controlling Microbes to Fight Infections" (CMFI), Tübingen, Germany; Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany; Partner-site Tübingen, German Center for Infection Research (DZIF), Tübingen, Germany
| | - Marcus D Hartmann
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany; Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany.
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3
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Chowdhury R, Bitar PDP, Bell KE, Altier C. Shigella flexneri utilizes intestinal signals to control its virulence. Gut Microbes 2023; 15:2256767. [PMID: 37741806 PMCID: PMC10519361 DOI: 10.1080/19490976.2023.2256767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 09/05/2023] [Indexed: 09/25/2023] Open
Abstract
The enteric pathogens have evolved to utilize elements from their surroundings to optimize their infection strategies. A common mechanism to achieve this is to employ intestinal compounds as signals to control the activity of a master regulator of virulence. Shigella flexneri (S. flexneri) is a highly infectious entero-invasive pathogen which requires very few organisms to cause invasion of the colonic mucosa. The invasion program is controlled by the virulence master regulator VirF. Here, we show that the fatty acids commonly found in the colon can be exploited by S. flexneri to repress its virulence, allowing it to energetically finance its proliferation, thus increasing its pathogenicity. Colonic fatty acids such as oleic, palmitoleic and cis-2-hexadecenoic acid were shown to directly bind to VirF and mediate its prompt degradation. These fatty acids also disrupted the ability of VirF to bind to its target DNA, suppressing the transcription of the downstream virulence genes and significantly reducing the invasion of S. flexneri to colonic epithelial cells. Treatment with colonic fatty acids significantly increased the growth rate of the pathogen only under invasion-inducing conditions, showing that the reduction in the burden of virulence promotes a growth advantage. These results demonstrate the process by which S. flexneri can employ intestinal compounds as signals to increase its numbers at its preferred site of invasion, highlighting the mechanism by which the full spectrum of shigellosis is achieved despite a miniscule infectious dose. This highlights an elegant model of environmental adaption by S. flexneri to maximize the pathogenic benefit.
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Affiliation(s)
- Rimi Chowdhury
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA
| | | | - Katherine E. Bell
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA
| | - Craig Altier
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA
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4
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Zhou J, Ma H, Zhang L. Mechanisms of Virulence Reprogramming in Bacterial Pathogens. Annu Rev Microbiol 2023; 77:561-581. [PMID: 37406345 DOI: 10.1146/annurev-micro-032521-025954] [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] [Indexed: 07/07/2023]
Abstract
Bacteria are single-celled organisms that carry a comparatively small set of genetic information, typically consisting of a few thousand genes that can be selectively activated or repressed in an energy-efficient manner and transcribed to encode various biological functions in accordance with environmental changes. Research over the last few decades has uncovered various ingenious molecular mechanisms that allow bacterial pathogens to sense and respond to different environmental cues or signals to activate or suppress the expression of specific genes in order to suppress host defenses and establish infections. In the setting of infection, pathogenic bacteria have evolved various intelligent mechanisms to reprogram their virulence to adapt to environmental changes and maintain a dominant advantage over host and microbial competitors in new niches. This review summarizes the bacterial virulence programming mechanisms that enable pathogens to switch from acute to chronic infection, from local to systemic infection, and from infection to colonization. It also discusses the implications of these findings for the development of new strategies to combat bacterial infections.
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Affiliation(s)
- Jianuan Zhou
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China;
| | - Hongmei Ma
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China;
| | - Lianhui Zhang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China;
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Nava-Galeana J, Yakhnin H, Babitzke P, Bustamante VH. CsrA Positively and Directly Regulates the Expression of the pdu, pocR, and eut Genes Required for the Luminal Replication of Salmonella Typhimurium. Microbiol Spectr 2023; 11:e0151623. [PMID: 37358421 PMCID: PMC10433801 DOI: 10.1128/spectrum.01516-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 05/26/2023] [Indexed: 06/27/2023] Open
Abstract
Enteric pathogens, such as Salmonella, have evolved to thrive in the inflamed gut. Genes located within the Salmonella pathogenicity island 1 (SPI-1) mediate the invasion of cells from the intestinal epithelium and the induction of an intestinal inflammatory response. Alternative electron acceptors become available in the inflamed gut and are utilized by Salmonella for luminal replication through the metabolism of propanediol and ethanolamine, using the enzymes encoded by the pdu and eut genes. The RNA-binding protein CsrA inhibits the expression of HilD, which is the central transcriptional regulator of the SPI-1 genes. Previous studies suggest that CsrA also regulates the expression of the pdu and eut genes, but the mechanism for this regulation is unknown. In this work, we show that CsrA positively regulates the pdu genes by binding to the pocR and pduA transcripts as well as the eut genes by binding to the eutS transcript. Furthermore, our results show that the SirA-CsrB/CsrC-CsrA regulatory cascade controls the expression of the pdu and eut genes mediated by PocR or EutR, which are the positive AraC-like transcriptional regulators for the pdu and eut genes, respectively. By oppositely regulating the expression of genes for invasion and for luminal replication, the SirA-CsrB/CsrC-CsrA regulatory cascade could be involved in the generation of two Salmonella populations that cooperate for intestinal colonization and transmission. Our study provides new insight into the regulatory mechanisms that govern Salmonella virulence. IMPORTANCE The regulatory mechanisms that control the expression of virulence genes are essential for bacteria to infect hosts. Salmonella has developed diverse regulatory mechanisms to colonize the host gut. For instance, the SirA-CsrB/CsrC-CsrA regulatory cascade controls the expression of the SPI-1 genes, which are required for this bacterium to invade intestinal epithelium cells and for the induction of an intestinal inflammatory response. In this study, we determine the mechanisms by which the SirA-CsrB/CsrC-CsrA regulatory cascade controls the expression of the pdu and eut genes, which are necessary for the replication of Salmonella in the intestinal lumen. Thus, our data, together with the results of previous reports, indicate that the SirA-CsrB/CsrC-CsrA regulatory cascade has an important role in the intestinal colonization by Salmonella.
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Affiliation(s)
- Jessica Nava-Galeana
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Helen Yakhnin
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Paul Babitzke
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Víctor H. Bustamante
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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6
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Trirocco R, Pasqua M, Tramonti A, Colonna B, Paiardini A, Prosseda G. Diffusible signal factors (DSFs) bind and repress VirF, the leading virulence activator of Shigella flexneri. Sci Rep 2023; 13:13170. [PMID: 37580399 PMCID: PMC10425336 DOI: 10.1038/s41598-023-40023-w] [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: 05/29/2023] [Accepted: 08/03/2023] [Indexed: 08/16/2023] Open
Abstract
Shigella, the aetiological agent of human bacillary dysentery, controls the expression of its virulence determinants through an environmentally stimulated cascade of transcriptional activators. VirF is the leading activator and is essential for proper virulence expression. In this work, we report on in vitro and in vivo experiments showing that two autoinducers of the DSF family, XcDSF and BDSF interact with the jelly roll module of VirF causing its inhibition and affecting the expression of the entire virulence system of Shigella, including its ability to invade epithelial cells. We propose a molecular model explaining how the binding of XcDSF and BDSF causes inhibition of VirF by preventing its dimerization. Overall, our experimental results suggest that XcDSF and BDSF may contribute to "colonisation resistance" in the human gut or, alternatively, may be exploited for the fine-tuning of Shigella virulence expression as the bacterium migrates from the lumen to approach the intestinal mucosa. Our findings also stress how a detailed understanding of the interaction of DSF ligands with VirF may contribute to the rational development of innovative antivirulence drugs to treat shigellosis.
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Affiliation(s)
- Rita Trirocco
- Institute Pasteur Italia, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy
| | - Martina Pasqua
- Institute Pasteur Italia, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy
| | - Angela Tramonti
- Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy
| | - Bianca Colonna
- Institute Pasteur Italia, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy
| | - Alessandro Paiardini
- Department of Biochemical Sciences, Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy
| | - Gianni Prosseda
- Institute Pasteur Italia, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy.
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Trirocco R, Pasqua M, Tramonti A, Grossi M, Colonna B, Paiardini A, Prosseda G. Fatty Acids Abolish Shigella Virulence by Inhibiting Its Master Regulator, VirF. Microbiol Spectr 2023; 11:e0077823. [PMID: 37140433 PMCID: PMC10269687 DOI: 10.1128/spectrum.00778-23] [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: 02/20/2023] [Accepted: 04/10/2023] [Indexed: 05/05/2023] Open
Abstract
The pathogenicity of Shigella, the intracellular pathogen responsible for human bacillary dysentery, depends on a coordinated and tightly regulated expression of its virulence determinants. This is the result of a cascade organization of its positive regulators, with VirF, a transcriptional activator belonging to the AraC-XylS family, in a pivotal position. VirF itself is submitted to several well-known regulations at the transcriptional level. In this work, we present evidence for a novel posttranslational regulatory mechanism of VirF mediated by the inhibitory interaction with specific fatty acids. By homology modeling and molecular docking analyses, we identify a jelly roll motif in the structure of ViF capable of interacting with medium-chain saturated and long-chain unsaturated fatty acids. In vitro and in vivo assays show that capric, lauric, myristoleic, palmitoleic, and sapienic acids interact effectively with the VirF protein, abolishing its transcription-promoting activity. This silences the virulence system of Shigella, leading to a drastic reduction in its ability to invade epithelial cells and proliferate in their cytoplasm. IMPORTANCE In the absence of a valid vaccine, the main therapeutic approach currently used to treat shigellosis is based on the use of antibiotics. The emergence of antibiotic resistance jeopardizes the future effectiveness of this approach. The importance of the present work resides both in the identification of a new level of posttranslational regulation of the Shigella virulence system and in the characterization of a mechanism offering new opportunities for the design of antivirulence compounds, which may change the treatment paradigm of Shigella infections by limiting the emergence of antibiotic-resistant bacteria.
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Affiliation(s)
- Rita Trirocco
- Institute Pasteur Italia, Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | - Martina Pasqua
- Institute Pasteur Italia, Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | - Angela Tramonti
- Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy
| | - Milena Grossi
- Institute Pasteur Italia, Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | - Bianca Colonna
- Institute Pasteur Italia, Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
| | | | - Gianni Prosseda
- Institute Pasteur Italia, Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University of Rome, Rome, Italy
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8
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Chowdhury R, Pavinski Bitar PD, Chapman HM, Altier C. Salmonella Invasion Is Controlled by Competition among Intestinal Chemical Signals. mBio 2023; 14:e0001223. [PMID: 37017539 PMCID: PMC10127606 DOI: 10.1128/mbio.00012-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/14/2023] [Indexed: 04/06/2023] Open
Abstract
The intestine is a complex, ever-changing environment replete with an array of signaling molecules. To colonize such a complex organ, pathogens have adapted to utilize specific cues from the local environment to intricately regulate the expression of their virulence determinants. Salmonella preferentially colonizes the distal ileum, a niche enriched in the metabolite formic acid. Here, we show that the relatively higher concentration of this metabolite in the distal ileum prevents other signals from repressing Salmonella invasion in that region. We show that imported and unmetabolized formic acid functions as a cytoplasmic signal that competitively binds to HilD, the master transcriptional regulator of Salmonella invasion, thus preventing repressive fatty acids from binding to the protein. This results in an increased lifetime of HilD and subsequent derepression of invasion genes. This study demonstrates an important mechanism by which Salmonella utilizes competition among signals in the gut to its advantage as a pathogen. IMPORTANCE Enteric pathogens acutely sense their environment for signals to regulate their virulence functions. We demonstrate here that the enteric pathogen Salmonella utilizes the competition among certain regional intestinal constituents to modulate its virulence determinants in that region. We show that the high concentration of formic acid in the ileum outcompetes other signals and triggers the activation of virulence genes in the ileum. This study shows a delicate spatial and temporal mechanism by which enteric pathogens may utilize the competition among environmental cues to optimize their pathogenicity.
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Affiliation(s)
- Rimi Chowdhury
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Paulina D. Pavinski Bitar
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Hanora M. Chapman
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Craig Altier
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
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9
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Dolores Arista-Regalado A, Barba-León J, Humberto Bustamante V, Alberto Flores-Valdez M, Gaona J, Juliana Fajardo-Guerrero M. hilD is required for the active internalization of Salmonella Newport into cherry tomatoes. J Food Prot 2023; 86:100085. [PMID: 37003533 DOI: 10.1016/j.jfp.2023.100085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 04/03/2023]
Abstract
Salmonella enterica is a foodborne pathogen that can be internalized into fresh produce. Most of the Salmonella virulence genes are clustered in regions denominated Salmonella Pathogenicity Islands (SPI). SPI-1 encodes a Type Three Secretion System (T3SS-1) and effector proteins that allow the internalization of Salmonella into animal cells. HilD is a transcriptional regulator that induces expression of SPI-1 genes and other related virulence genes located outside of this island. Here, we assessed the role of hilD in the internalization of Salmonella Newport and Typhimurium into cherry tomatoes, by evaluating either an isolate from an avocado orchard, S. Newport-45, and the laboratory strain S. Typhimurium SL1344 and their isogenic mutants in hilD. The internalization of these bacteria was carried out by using a temperature gradient of 12 °C. The transcription of hilD and invA was tested by qRT-PCR experiments. Our results show that S. Newport-45 hilD mutant viable cells obtained from the interior of the fruit were decreased (2.7-fold), compared with those observed for S. Typhimurium SL1344. Interestingly, at 3 days post-inoculation, the cells recovered from S. Newport-45 hilD mutant were similar to those recovered from all the strains evaluated, suggesting that hilD is required only for the initial internalization of S. Newport.
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10
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Inflammatory Response: A Crucial Way for Gut Microbes to Regulate Cardiovascular Diseases. Nutrients 2023; 15:nu15030607. [PMID: 36771313 PMCID: PMC9921390 DOI: 10.3390/nu15030607] [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: 12/13/2022] [Revised: 01/09/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
Gut microbiota is the largest and most complex microflora in the human body, which plays a crucial role in human health and disease. Over the past 20 years, the bidirectional communication between gut microbiota and extra-intestinal organs has been extensively studied. A better comprehension of the alternative mechanisms for physiological and pathophysiological processes could pave the way for health. Cardiovascular disease (CVD) is one of the most common diseases that seriously threatens human health. Although previous studies have shown that cardiovascular diseases, such as heart failure, hypertension, and coronary atherosclerosis, are closely related to gut microbiota, limited understanding of the complex pathogenesis leads to poor effectiveness of clinical treatment. Dysregulation of inflammation always accounts for the damaged gastrointestinal function and deranged interaction with the cardiovascular system. This review focuses on the characteristics of gut microbiota in CVD and the significance of inflammation regulation during the whole process. In addition, strategies to prevent and treat CVD through proper regulation of gut microbiota and its metabolites are also discussed.
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11
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Yang X, Stein KR, Hang HC. Anti-infective bile acids bind and inactivate a Salmonella virulence regulator. Nat Chem Biol 2023; 19:91-100. [PMID: 36175659 PMCID: PMC9805502 DOI: 10.1038/s41589-022-01122-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 07/26/2022] [Indexed: 01/03/2023]
Abstract
Bile acids are prominent host and microbiota metabolites that modulate host immunity and microbial pathogenesis. However, the mechanisms by which bile acids suppress microbial virulence are not clear. To identify the direct protein targets of bile acids in bacterial pathogens, we performed activity-guided chemical proteomic studies. In Salmonella enterica serovar Typhimurium, chenodeoxycholic acid (CDCA) most effectively inhibited the expression of virulence genes and invasion of epithelial cells and interacted with many proteins. Notably, we discovered that CDCA can directly bind and inhibit the function of HilD, an important transcriptional regulator of S. Typhimurium virulence and pathogenesis. Our characterization of bile acid-resistant HilD mutants in vitro and in S. Typhimurium infection models suggests that HilD is one of the key protein targets of anti-infective bile acids. This study highlights the utility of chemical proteomics to identify the direct protein targets of microbiota metabolites for mechanistic studies in bacterial pathogens.
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Affiliation(s)
- Xinglin Yang
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA, USA
| | - Kathryn R Stein
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA, USA
| | - Howard C Hang
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA, USA.
- Department of Chemistry, Scripps Research, La Jolla, CA, USA.
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12
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Rather MA, Chowdhury R, Pavinski Bitar PD, Altier C. Recombinant production of a diffusible signal factor inhibits Salmonella invasion and animal carriage. Gut Microbes 2023; 15:2208498. [PMID: 37158497 PMCID: PMC10171134 DOI: 10.1080/19490976.2023.2208498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/21/2023] [Indexed: 05/10/2023] Open
Abstract
The complex chemical environment of the intestine is defined largely by the metabolic products of the resident microbiota. Enteric pathogens, elegantly evolved to thrive in the gut, use these chemical products as signals to recognize specific niches and to promote their survival and virulence. Our previous work has shown that a specific class of quorum-sensing molecules found within the gut, termed diffusible signal factors (DSF), signals the repression of Salmonella tissue invasion, thus defining a means by which this pathogen recognizes its location and modulates virulence to optimize its survival. Here, we determined whether the recombinant production of a DSF could reduce Salmonella virulence in vitro and in vivo. We found that the most potent repressor of Salmonella invasion, cis-2-hexadecenoic acid (c2-HDA), could be recombinantly produced in E. coli by the addition of a single exogenous gene encoding a fatty acid enoyl-CoA dehydratase/thioesterase and that co-culture of the recombinant strain with Salmonella potently inhibited tissue invasion by repressing Salmonella genes required for this essential virulence function. Using the well characterized E. coli Nissle 1917 strain and a chicken infection model, we found that the recombinant DSF-producing strain could be stably maintained in the large intestine. Further, challenge studies demonstrated that this recombinant organism could significantly reduce Salmonella colonization of the cecum, the site of carriage in this animal species. These findings thus describe a plausible means by which Salmonella virulence may be affected in animals by in situ chemical manipulation of functions essential for colonization and virulence.
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Affiliation(s)
- Mudasir Ali Rather
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA
| | - Rimi Chowdhury
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA
| | | | - Craig Altier
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA
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13
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Disarming the pathogen. Nat Chem Biol 2023; 19:5-6. [PMID: 36175660 DOI: 10.1038/s41589-022-01133-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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14
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Zhao X, Yang X, Hang HC. Chemoproteomic Analysis of Microbiota Metabolite-Protein Targets and Mechanisms. Biochemistry 2022; 61:2822-2834. [PMID: 34989554 PMCID: PMC9256862 DOI: 10.1021/acs.biochem.1c00758] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The microbiota have emerged as an important factor in host physiology, disease, and response to therapy. These diverse microbes (bacteria, virus, fungi, and protists) encode unique functions and metabolites that regulate intraspecies and interspecies interactions. While the mechanisms of some microbiota species and metabolites have been elucidated, the diversity and abundance of different microbiota species and their associated pathways suggest many more metabolites and mechanisms of action remain to be discovered. In this Perspective, we highlight how the advances in chemical proteomics have provided new opportunities to elucidate the molecular targets of specific microbiota metabolites and reveal new mechanisms of action. The continued development of specific microbiota metabolite reporters and more precise proteomic methods should reveal new microbiota mechanisms of action, therapeutic targets, and biomarkers for a variety of human diseases.
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Zhang X, Liu B, Ding X, Bin P, Yang Y, Zhu G. Regulatory Mechanisms between Quorum Sensing and Virulence in Salmonella. Microorganisms 2022; 10:2211. [PMID: 36363803 PMCID: PMC9693372 DOI: 10.3390/microorganisms10112211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 08/28/2023] Open
Abstract
Salmonella is a foodborne pathogen that causes enterogastritis among humans, livestock and poultry, and it not only causes huge economic losses for the feed industry but also endangers public health around the world. However, the prevention and treatment of Salmonella infection has remained poorly developed because of its antibiotic resistance. Bacterial quorum sensing (QS) system is an intercellular cell-cell communication mechanism involving multiple cellular processes, especially bacterial virulence, such as biofilm formation, motility, adherence, and invasion. Therefore, blocking the QS system may be a new strategy for Salmonella infection independent of antibiotic treatment. Here, we have reviewed the central role of the QS system in virulence regulation of Salmonella and summarized the most recent advances about quorum quenching (QQ) in virulence attenuation during Salmonella infection. Unraveling the complex relationship between QS and bacterial virulence may provide new insight into the therapy of pathogen infection.
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Affiliation(s)
- Xiaojie Zhang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Baobao Liu
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Xueyan Ding
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Peng Bin
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Yang Yang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Guoqiang Zhu
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint Laboratory of International Cooperation on Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou University, Yangzhou 225009, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
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16
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Tate H, Hsu CH, Chen JC, Han J, Foley SL, Folster JP, Francois Watkins LK, Reynolds J, Tillman GE, Nyirabahizi E, Zhao S. Genomic Diversity, Antimicrobial Resistance, and Virulence Gene Profiles of Salmonella Serovar Kentucky Isolated from Humans, Food, and Animal Ceca Content Sources in the United States. Foodborne Pathog Dis 2022; 19:509-521. [PMID: 35960531 DOI: 10.1089/fpd.2022.0005] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Salmonella serovar Kentucky is frequently isolated from chickens and dairy cattle, but recovery from humans is comparatively low based on the U.S. National Antimicrobial Resistance Monitoring System (NARMS) reports. We aimed to better describe the genetic diversity, antimicrobial resistance, and virulence determinants of Salmonella Kentucky isolates from humans, food animal ceca, retail meat and poultry products, imported foods and food products, and other samples. We analyzed the genomes of 774 Salmonella Kentucky isolates and found that 63% (54/86) of human isolates were sequence type (ST)198, 33% (29/86) were ST152, and 3.5% (3/86) were ST314. Ninety-one percent (570/629) of cecal isolates and retail meat and poultry isolates were ST152 or ST152-like (one allele difference), and 9.2% (58/629) were ST198. Isolates from imported food were mostly ST198 (60%, 22/37) and ST314 (29.7%, 11/37). ST198 isolates clustered into two main lineages. Clade ST198.2 comprised almost entirely isolates from humans and imported foods, all containing triple mutations in the quinolone resistance-determining region (QRDR) that confer resistance to fluoroquinolones. Clade ST198.1 contained isolates from humans, ceca, retail meat and poultry products, and imported foods that largely lacked QRDR mutations. ST152 isolates from cattle had a lineage (Clade 2) distinct from ST152 isolates from chicken (Clade 4), and half of ST152 human isolates clustered within two other clades (Clades 1 and 3), largely distinct from Clades 2 and 4. Although clinical illness associated with Salmonella Kentucky is low, ST198 appears to account for most human infections in the Unites States but is uncommon among ceca of domestic food animals and retail meat and poultry products. These findings, combined with human exposure data, suggest that fluoroquinolone-resistant ST198 infections may be linked to the consumption of food products that are imported or consumed while traveling. We also found unique differences in the composition of virulence genes and antimicrobial resistance genes among the clades, which may provide clues to the host specificity and pathogenicity of Salmonella Kentucky lineages.
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Affiliation(s)
- Heather Tate
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, Maryland, USA
| | - Chih-Hao Hsu
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, Maryland, USA
| | - Jessica C Chen
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jing Han
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Steven L Foley
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA
| | - Jason P Folster
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Louise K Francois Watkins
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jared Reynolds
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Glenn E Tillman
- Food Safety and Inspection Service, U.S. Department of Agriculture, Athens, Georgia, USA
| | - Epiphanie Nyirabahizi
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, Maryland, USA
| | - Shaohua Zhao
- Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, Maryland, USA
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17
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Mitchell MK, Ellermann M. Long Chain Fatty Acids and Virulence Repression in Intestinal Bacterial Pathogens. Front Cell Infect Microbiol 2022; 12:928503. [PMID: 35782143 PMCID: PMC9247172 DOI: 10.3389/fcimb.2022.928503] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
When bacterial pathogens enter the gut, they encounter a complex milieu of signaling molecules and metabolites produced by host and microbial cells or derived from external sources such as the diet. This metabolomic landscape varies throughout the gut, thus establishing a biogeographical gradient of signals that may be sensed by pathogens and resident bacteria alike. Enteric bacterial pathogens have evolved elaborate mechanisms to appropriately regulate their virulence programs, which involves sensing and responding to many of these gut metabolites to facilitate successful gut colonization. Long chain fatty acids (LCFAs) represent major constituents of the gut metabolome that can impact bacterial functions. LCFAs serve as important nutrient sources for all cellular organisms and can function as signaling molecules that regulate bacterial metabolism, physiology, and behaviors. Moreover, in several enteric pathogens, including Salmonella enterica, Listeria monocytogenes, Vibrio cholerae, and enterohemorrhagic Escherichia coli, LCFA sensing results in the transcriptional repression of virulence through two general mechanisms. First, some LCFAs function as allosteric inhibitors that decrease the DNA binding affinities of transcriptional activators of virulence genes. Second, some LCFAs also modulate the activation of histidine kinase receptors, which alters downstream intracellular signaling networks to repress virulence. This mini-review will summarize recent studies that have investigated the molecular mechanisms by which different LCFA derivatives modulate the virulence of enteric pathogens, while also highlighting important gaps in the field regarding the roles of LCFAs as determinants of infection and disease.
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18
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Making Sense of Quorum Sensing at the Intestinal Mucosal Interface. Cells 2022; 11:cells11111734. [PMID: 35681429 PMCID: PMC9179481 DOI: 10.3390/cells11111734] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 12/12/2022] Open
Abstract
The gut microbiome can produce metabolic products that exert diverse activities, including effects on the host. Short chain fatty acids and amino acid derivatives have been the focus of many studies, but given the high microbial density in the gastrointestinal tract, other bacterial products such as those released as part of quorum sensing are likely to play an important role for health and disease. In this review, we provide of an overview on quorum sensing (QS) in the gastrointestinal tract and summarise what is known regarding the role of QS molecules such as auto-inducing peptides (AIP) and acyl-homoserine lactones (AHL) from commensal, probiotic, and pathogenic bacteria in intestinal health and disease. QS regulates the expression of numerous genes including biofilm formation, bacteriocin and toxin secretion, and metabolism. QS has also been shown to play an important role in the bacteria–host interaction. We conclude that the mechanisms of action of QS at the intestinal neuro–immune interface need to be further investigated.
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19
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Fan Q, Zuo J, Wang H, Grenier D, Yi L, Wang Y. Contribution of quorum sensing to virulence and antibiotic resistance in zoonotic bacteria. Biotechnol Adv 2022; 59:107965. [PMID: 35487393 DOI: 10.1016/j.biotechadv.2022.107965] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/15/2022] [Accepted: 04/21/2022] [Indexed: 11/02/2022]
Abstract
Quorum sensing (QS), which is a key part of cell/cell communication, is widely distributed in microorganisms, especially in bacteria. Bacteria can produce and detect the presence of QS signal molecule, perceive the composition and density of microorganisms in their complex habitat, and then dynamically regulate their own gene expression to adapt to their environment. Among the many traits controlled by QS in pathogenic bacteria is the expression of virulence factors and antibiotic resistance. Many pathogenic bacteria rely on QS to govern the production of virulence factors and express drug-resistance, especially in zoonotic bacteria. The threat of antibiotic resistant zoonotic bacteria has called for alternative antimicrobial strategies that would mitigate the increase of classical resistance mechanism. Targeting QS has proven to be a promising alternative to conventional antibiotic for controlling infections. Here we review the QS systems in common zoonotic pathogenic bacteria and outline how QS may control the virulence and antibiotic resistance of zoonotic bacteria.
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Affiliation(s)
- Qingying Fan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Jing Zuo
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Haikun Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Daniel Grenier
- Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire, Université Laval, Quebec City, Canada
| | - Li Yi
- Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China; College of Life Science, Luoyang Normal University, Luoyang, China.
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China.
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20
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Scala V, Salustri M, Loreti S, Pucci N, Cacciotti A, Tatulli G, Scortichini M, Reverberi M. Mass Spectrometry-Based Targeted Lipidomics and Supervised Machine Learning Algorithms in Detecting Disease, Cultivar, and Treatment Biomarkers in Xylella fastidiosa subsp. pauca-Infected Olive Trees. FRONTIERS IN PLANT SCIENCE 2022; 13:833245. [PMID: 35528940 PMCID: PMC9072861 DOI: 10.3389/fpls.2022.833245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/08/2022] [Indexed: 06/14/2023]
Abstract
In 2013, Xylella fastidiosa (Xf) was detected for the first time in Apulia and, subsequently, recognized as the causal agent of the olive quick decline syndrome (OQDS). To contain the disease, the olive germplasm was evaluated for resistance to Xf, identifying cultivars with different susceptibility to the pathogen. Regarding this, the resistant cultivar Leccino has generally a lower bacterial titer compared with the susceptible cultivar Ogliarola salentina. Among biomolecules, lipids could have a pivotal role in the interaction of Xf with its host. In the grapevine Pierce's disease, fatty acid molecules, the diffusible signaling factors (DSFs), act as regulators of Xf lifestyle and are crucial for its virulence. Other lipid compounds derived from fatty acid oxidation, namely, oxylipins, can affect, in vitro, biofilm formation in Xf subsp. pauca (Xfp) strain De Donno, that is, the strain causing OQDS. In this study, we combined high-performance liquid chromatography-mass spectrometry-MS-based targeted lipidomics with supervised learning algorithms (random forest, support vector machine, and neural networks) to classify olive tree samples from Salento. The dataset included samples from either OQDS-positive or OQDS-negative olive trees belonging either to cultivar Ogliarola salentina or Leccino treated or not with the zinc-copper-citric acid biocomplex Dentamet®. We built classifiers using the relative differences in lipid species able to discriminate olive tree samples, namely, (1) infected and non-infected, (2) belonging to different cultivars, and (3) treated or untreated with Dentamet®. Lipid entities emerging as predictors of the thesis are free fatty acids (C16:1, C18:1, C18:2, C18:3); the LOX-derived oxylipins 9- and 13-HPOD/TrE; the DOX-derived oxylipin 10-HPOME; and diacylglyceride DAG36:4(18:1/18:3).
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Affiliation(s)
- Valeria Scala
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, Rome, Italy
| | - Manuel Salustri
- Department of Environmental Biology, Sapienza University, Rome, Italy
| | - Stefania Loreti
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, Rome, Italy
| | - Nicoletta Pucci
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, Rome, Italy
| | - Andrea Cacciotti
- Department of Environmental Biology, Sapienza University, Rome, Italy
| | - Giuseppe Tatulli
- Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification, Rome, Italy
| | - Marco Scortichini
- Council for Agricultural Research and Economics (CREA), Research Centre for Olive, Fruit and Citrus Crops, Rome, Italy
| | - Massimo Reverberi
- Department of Environmental Biology, Sapienza University, Rome, Italy
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21
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Shao S, Zhang Y, Yin K, Zhang Y, Wei L, Wang Q. FabR senses long-chain unsaturated fatty acids to control virulence in pathogen Edwardsiella piscicida. Mol Microbiol 2022; 117:737-753. [PMID: 34932231 DOI: 10.1111/mmi.14869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/11/2021] [Accepted: 12/18/2021] [Indexed: 11/28/2022]
Abstract
Long-chain unsaturated fatty acids (UFAs) can serve as nutrient sources or building blocks for bacterial membranes. However, little is known about how UFAs may be incorporated into the virulence programs of pathogens. A previous investigation identified FabR as a positive regulator of virulence gene expression in Edwardsiella piscicida. Here, chromatin immunoprecipitation-sequencing coupled with RNA-seq analyses revealed that 10 genes were under the direct control of FabR, including fabA, fabB, and cfa, which modulate the composition of UFAs. The binding of FabR to its target DNA was facilitated by oleoyl-CoA and inhibited by stearoyl-CoA. In addition, analyses of enzyme mobility shift assay and DNase I footprinting with wild-type and a null mutant (F131A) of FabR demonstrated crucial roles of FabR in binding to the promoters of fabA, fabB, and cfa. Moreover, FabR also binds to the promoter region of the virulence regulator esrB for its activation, facilitating the expression of the type III secretion system (T3SS) in response to UFAs. Furthermore, FabR coordinated with RpoS to modulate the expression of T3SS. Collectively, our results elucidate the molecular machinery of FabR regulating bacterial fatty acid composition and virulence in enteric pathogens, further expanding our knowledge of its crucial role in host-pathogen interactions.
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Affiliation(s)
- Shuai Shao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yi Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Kaiyu Yin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yuanxing Zhang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Lifan Wei
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Department of Endodontics and Operative Dentistry, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
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22
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Chowdhury R, Pavinski Bitar PD, Adams MC, Chappie JS, Altier C. AraC-type regulators HilC and RtsA are directly controlled by an intestinal fatty acid to regulate Salmonella invasion. Mol Microbiol 2021; 116:1464-1475. [PMID: 34687258 DOI: 10.1111/mmi.14835] [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: 07/29/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 01/30/2023]
Abstract
Invasion of the intestinal epithelium is an essential but energetically expensive survival strategy and is, therefore, tightly regulated by using specific cues from the environment. The enteric pathogen Salmonella controls its invasion machinery through the elegant coordination of three AraC-type transcription activators, HilD, HilC, and RtsA. Most environmental signals target HilD to control invasion, whereas HilC and RtsA are known only to augment these effects on HilD. Here we show that a fatty acid found in the murine colon, cis-2-hexadecenoic acid (c2-HDA), represses Salmonella invasion by directly targeting HilC and RtsA, in addition to HilD. c2-HDA directly binds each of these regulators and inhibits their attachment to DNA targets, repressing invasion even in the absence of HilD. Fatty acid binding, however, does not affect HilC and RtsA protein stability, unlike HilD. Importantly, we show that HilC and RtsA are highly effective in restoring HilD production and invasion gene expression after elimination of the repressive fatty acid c2-HDA. Together, these results illuminate a precise mechanism by which HilC and RtsA may modulate invasion as Salmonella navigates through different regions of the intestine, contributing to our understanding of how this enteric pathogen senses and adapts to a diverse intestinal environment while maintaining its virulence.
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Affiliation(s)
- Rimi Chowdhury
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Paulina D Pavinski Bitar
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Myfanwy C Adams
- Department of Molecular Medicine, Cornell University, Ithaca, New York, USA
| | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, New York, USA
| | - Craig Altier
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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23
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Lazar V, Holban AM, Curutiu C, Chifiriuc MC. Modulation of Quorum Sensing and Biofilms in Less Investigated Gram-Negative ESKAPE Pathogens. Front Microbiol 2021; 12:676510. [PMID: 34394026 PMCID: PMC8359898 DOI: 10.3389/fmicb.2021.676510] [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: 03/05/2021] [Accepted: 06/30/2021] [Indexed: 01/20/2023] Open
Abstract
Pathogenic bacteria have the ability to sense their versatile environment and adapt by behavioral changes both to the external reservoirs and the infected host, which, in response to microbial colonization, mobilizes equally sophisticated anti-infectious strategies. One of the most important adaptive processes is the ability of pathogenic bacteria to turn from the free, floating, or planktonic state to the adherent one and to develop biofilms on alive and inert substrata; this social lifestyle, based on very complex communication networks, namely, the quorum sensing (QS) and response system, confers them an increased phenotypic or behavioral resistance to different stress factors, including host defense mechanisms and antibiotics. As a consequence, biofilm infections can be difficult to diagnose and treat, requiring complex multidrug therapeutic regimens, which often fail to resolve the infection. One of the most promising avenues for discovering novel and efficient antibiofilm strategies is targeting individual cells and their QS mechanisms. A huge amount of data related to the inhibition of QS and biofilm formation in pathogenic bacteria have been obtained using the well-established gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa models. The purpose of this paper was to revise the progress on the development of antibiofilm and anti-QS strategies in the less investigated gram-negative ESKAPE pathogens Klebsiella pneumoniae, Acinetobacter baumannii, and Enterobacter sp. and identify promising leads for the therapeutic management of these clinically significant and highly resistant opportunistic pathogens.
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Affiliation(s)
- Veronica Lazar
- Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, Bucharest, Romania
- The Research Institute of the University of Bucharest, Bucharest, Romania
| | - Alina Maria Holban
- Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, Bucharest, Romania
- The Research Institute of the University of Bucharest, Bucharest, Romania
| | - Carmen Curutiu
- Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, Bucharest, Romania
- The Research Institute of the University of Bucharest, Bucharest, Romania
| | - Mariana Carmen Chifiriuc
- Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, Bucharest, Romania
- The Research Institute of the University of Bucharest, Bucharest, Romania
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